Report on the Work of the Institute of Physics and Technology

A. F. Ioffe, Leningrad

The Conditions of My Scientific Work

In a single report I must give an account of all my thirty years of scientific activity. Having begun scientific work in Munich, I transferred it in 1906 to what was then St. Petersburg. Through the years of tsarist reaction, imperialist war, and chauvinism, through the heroic but difficult years of the civil war, my scientific life passed into the epoch of the building of socialism. The Revolution changed its inner content. In the pre-revolutionary period, science was for me only a beloved occupation, whose social significance interested me little. From the beginning of the Revolution it at the same time became part of the greatest task of building a communist society. I am happy that I understood this new significance of science comparatively early and actively built physics as the scientific basis of socialist technology. For this purpose the Physico-Technical Institute was founded, with which all my scientific work is connected. It deepened and broadened considerably in the epoch of the Revolution; its most important results belong to this epoch; I hope that I have also brought some benefit to socialist construction.

In physics itself the last thirty years have been marked by radical shifts. The beginning of my work coincided with the victorious advance of atomism. From the phenomenological description of phenomena, physics was moving toward the study of their mechanism; from aggregate results—to elementary processes. By my works of 1909, 1911, and 1913 I took part in substantiating the atomic structure of electricity and the quantum nature of light.

In 1912 Laue discovered the interference of X-rays in the atomic lattices of crystals; on this basis Born constructed the electrical theory of crystal lattices. In 1913 Bohr’s model of the atom appeared, which became the guiding thread for all atomic physics. These were the foundations for my work on the study of solids. I tried to fill Born’s formal theory of lattices with physical content by studying the properties of crystals. One of the experiments establishing the quantum nature of light was carried out by me and Dobronravov in 1924.

The contradictions in the model of the atom led in 1925 to the appearance of wave mechanics, which in its logical harmony and

in the scope of accumulated experience surpasses everything that physics knew before. A fundamental revision of the foundations of all physics became necessary. At the same time, many of my views on processes in solids changed as well, and the character of their investigation also changed. The experiments on the polarization of electron waves, published by me and Arsen’eva, belong to the period of the substantiation of wave mechanics.

Having revealed the atomic nucleus, wave mechanics here reaches the limits of its applicability. We are entering a new stage of theoretical physics, which in technology is reflected in the transition from hundreds of thousands of volts to millions and tens of millions of volts. Here new discoveries and new radical shifts still await us.

My scientific life has passed through all these stages.

Far from everything that I thought 30 or 10 years ago has retained its significance for me even now. Not all directions of investigation proved fruitful and correct. In some works I later found direct errors. However, my principal scientific work over the course of all 30 years constitutes a systematic development and deepening of the problem of the solid body and electricity. In the modern scientific picture I see many areas established and clarified by our works or arising under their influence. The prolonged polemic that unfolded around our views proved fruitful, since it called forth a whole stream of new facts.

In 18 years I have printed about 40 works, while the Physico-Technical Institute has printed about 500; moreover, in recent years the number of works has been growing from year to year—the PTI is on the rise in its scientific output. A summary of the most important results of these works is given in the materials for my report. Without repeating them, I shall try to unfold before you the main points of our investigations of the solid body and the atomic nucleus. From our collective work I often cannot single out my personal share and therefore in what follows I shall speak of our work, in which I took an active part.

Mechanical Properties of Crystals

A typical solid body is considered to be a crystal with a strictly periodic arrangement of individual elements (atoms and molecules). This is that mutual arrangement of atoms which corresponds to the least free energy of the body. Any change in this most advantageous arrangement requires the expenditure of external work and creates forces striving to return the crystal to its natural state. Such is the origin of the elasticity of solid bodies.

Subjecting a crystal to the action of an electric field, we displace the positive charges present in it in the direction of the field, and the negative ones in the opposite direction. This is dielectric polarization. Finally, in a crystal there are charges capable, under the action of a field, of creating a current. Thus are represented the properties of crystals under static or very slowly varying actions; the model of the crystal qualitatively explains these its

properties. But the twentieth century created fast-acting machines, rotating not hundreds, but thousands and tens of thousands of times per minute; currents with a number of alternations not of one hundred, but of a million and one hundred million per second. It became necessary to study the action of mechanical and electrical forces in time, and here, too, a number of new phenomena unforeseen by the model of the crystal were discovered: elastic aftereffect, fatigue, work hardening, impact brittleness, dielectric losses, hysteresis, etc.

Physics at first reacted to these phenomena by a purely descriptive study of them. Experimental material began to accumulate, united under the term “anomalies,” dielectric and mechanical. The French physicist Bouasse, in his major work on the mechanical properties of metals, comes to the conclusion that in this field there are no laws at all, and that the properties of each piece of iron must be studied separately in order to predict its behavior in a machine. A gap had formed between our conceptions of a solid body and its actual behavior. Theory did not understand practice. The principal aim of my scientific work was to eliminate this gap.

The first phenomenon that I tried to understand was elastic aftereffect. Any deformation leaves a slowly disappearing trace, and the traces of all the actions experienced by a body are superposed upon one another. In a homogeneous, properly constructed crystal there should be no place for aftereffect. But the bodies in which elastic aftereffect was observed were not such crystals. I therefore undertook the study of aftereffect in a quartz crystal and showed experimentally that there is no true aftereffect in it, and that the observed lag phenomena can be reduced to piezoelectric and thermal changes. This result was used for measuring instruments and was brilliantly confirmed by radio engineering. Stabilization by piezoquartz in fact gives no damping whatever. That, on the contrary, with a complex chemical and physical structure of the body aftereffect arises, was shown in his time by Maxwell. A very important further advance in this question has recently been achieved at the Kharkov Physico-Technical Institute by V. Gorskii, who created a theory of elastic aftereffect in alloy crystals.

With elastic aftereffect, the body nevertheless, in the final analysis, returns to its original form. But under stronger actions a solid body flows like a viscous liquid and changes its form for a long time. This phenomenon of plasticity, especially sharply manifested at high temperatures, is widely used in technology in forging and rolling. Plasticity is observed not only in complex aggregates of crystallites, such as engineering metals, but also in individual crystals. Lehmann saw in the plasticity of rock-salt crystals the appearance of a new modification of a special kind; there were no other explanations at all. How can a crystal, without action from outside, remain bent, when its atoms strive to arrange themselves in regular rows?

The X-ray method made it possible to trace not only the external changes in the shape of a crystal, but also those rearrangements which the atoms undergo inside the crystal. As early as 1918 we used X-rays to study plastic deformation, observing in the dark, on a fluorescent screen, the reflection of an X-ray beam from certain internal crystallographic planes filled with atoms. And here it became clear that, beginning with a certain load, the reflected spots suddenly split, multiply, and finally stretch out into whole tails. This means that, on passing a certain stress limit, the crystal breaks up into separate crystallites, displaced and rotated relative to one another. There is no longer an integral crystal—it is a conglomerate of crystallites arranged in a definite way.

The study of this phenomenon of asterism and of the structures (textures) arising during deformation of a crystal has since constituted an entire science; it is widely applied in factory laboratories and institutes for the study of metals, fibrous substances, rubber, and so on.

At first I thought that the first splitting of the spots observed in X-rays characterizes the elastic limit, i.e. the very beginning of residual deformation. But precise measurement of deformation, and in particular the optical method developed for this purpose by Obreimov and Shubnikov, showed that long before the first distortions of the radiographic pattern appear, slips along definite crystallographic planes are observed in the crystal. The more correctly a crystal is built, the earlier the first slips can be noticed. Klassen-Neklyudova and Podashevsky observed them already at \(9\ \text{g}/\text{mm}^2\), whereas the X-ray limit lies at \(900\ \text{g}/\text{mm}^2\) and corresponds not to the elastic limit, but to the yield point—the flow of an already deformed crystal under a stress changing only slightly. The yield point decreases with increasing temperature and reaches zero at the melting temperature. This was shown both for rock salt and for crystals of aluminum and magnesium. As is known, a liquid is characterized by the fact that its yield point is equal to zero. When a crystal, under the action of any influence, begins to flow, the crystal lattice becomes unstable—melting sets in. Later Schmid found that the yield point of bismuth, just before melting, ceases to decrease and does not reach zero, but I think that this is the result of recrystallization, of the appearance of intercrystalline elasticity.

Later we noticed a new effect—jerky deformation: under a continuously applied load the crystal stretches in separate jumps, accompanied by a sound. In a quiet room the phenomenon resembles the regular ticking of a clock. It turned out that each jump represents a displacement of \(1\text{–}2\ \mu\) and consists of an entire system of almost simultaneous slips. The phenomenon was studied both by us and abroad. A theory of it based on recrystallization was given by Davidenkov and Klassen-Neklyudova. With these

research was also associated a new method for obtaining metal single crystals, widely used both in our country and abroad.

After solving the riddle of the plasticity of crystals, the next problem was that of their low strength. The electrical theory of molecular forces asserted that the cohesive forces exceed by several hundred times the stresses at which a crystal breaks. Rock salt should withstand stresses up to \(200\ \mathrm{kg/mm^2}\), whereas in experiment, at all temperatures, it breaks at \(400\ \mathrm{g/mm^2}\).

Comparing the course of strength and of the yield point with temperature, we first of all established a distinction between the regions of brittle and plastic fracture. If the yield point is reached before the crystal breaks, then the process of flow itself strengthens, as we have shown, the crystal by a factor of \(10\)—\(12\), and fracture occurs at \(5\ \mathrm{kg/mm^2}\) instead of \(0.4\ \mathrm{kg/mm^2}\). At lower temperatures we have brittle fracture without flow, although with preliminary slips.

The very phenomenon of strengthening during the flow of a crystal shows that the cohesive forces are considerably greater than the usual practical strength. Fracture occurs not because the external force exceeds the cohesive forces over the whole fracture surface. In brittle fracture, when the strength is especially low, fracture usually begins from a sharp surface inhomogeneity, a crack or a sharp slip. At the edge of this crack the stress is concentrated; the crack tears farther, until the whole crystal is broken. In order to eliminate these sharp surface inhomogeneities at the moment of their appearance, I tried breaking salt in water and indeed obtained a striking effect. The salt did not break brittly, but stretched, and under strong tension withstood up to several tens of \(\mathrm{kg/mm^2}\). The main point was thereby clarified: the cohesive forces do indeed reach the theoretically calculated values, while the weak practical strength is determined by the mechanism of fracture and, first of all, by phenomena at the surface.

In another experiment we avoided the dangerous influence of the surface without immersing the salt in water. A ball of salt, preliminarily cooled in liquid air, was suddenly introduced into molten tin. In this case stresses arose inside it reaching \(50\ \mathrm{kg/mm^2}\), while on the surface there were no tensile forces at all.

The experiment with breaking salt in water provoked a lively discussion. The fact itself was confirmed many times—it now serves as a lecture demonstration—but the most varied explanations were offered for it. Smekal, for example, ascribed the great strength of salt to the penetration of water into the salt. Such penetration does in fact take place, but, as special experiments showed, it is not connected with the strengthening of the salt. A saturated solution of salt, although it penetrates inward, changes nothing in the properties of salt. It is enough to protect from the action of water a small portion of the surface of the salt in order to ensure brittle fracture, although water still enters the salt as easily as usual. Our experiments directly show that

that the principal source of low strength lies on the surface of the crystal. This is shown by direct experiments in which scratches are made on salt. In Stepanov’s view, the foci of destruction of a crystal are displacements that emerge on the surface during deformation.

In plastic rupture during the flow of a material, the displacements within the crystal itself are the dangerous ones. The surface here does not play an essential role. Studying the conditions of transition from brittleness to plasticity, Stepanov found crystals that resemble metal even in their sonority.

The role of the surface is especially clearly manifested in the brittle rupture of thin plates of mica or of threads of glass and quartz. Moisture adsorbed on the surface of a thread reduces its strength fivefold, alcohol threefold, and benzene twofold, as compared with a clean dry surface. Thin and short threads have a greater specific strength than thick and long ones. It is enough to remove the surface layer of glass by immersion in hydrofluoric acid in order to increase its strength several times. The same properties are also observed in the brittle rupture of steel. Polished or copper-coated steel is stronger than ground steel. Chromium plating reduces brittle strength.

The study of the mechanism of displacements and strengthening of crystals, of the mechanism of brittle and plastic rupture, of recrystallization, and of the role of the surface is continuing both at the Leningrad and at the Ural and Ukrainian Physico-Technical Institutes. Along with this, we are setting ourselves problems concerning the properties of intercrystalline bonds in metals and concerning plastics. Now, on the basis of quantum mechanics, a new and more advanced theory of crystal lattices and molecular interactions is beginning to be constructed. One may hope that the theory will help us better understand the mechanical properties of a solid body.

Dielectrics

The picture of the electrical properties of solid dielectrics appeared even more confused. The so-called electrical aftereffect of complex aggregates disappears in individual crystals. But here, too, the current decreases with time under constant voltage; when it ceases, a current of the opposite direction appears. Some specimens conduct thousands of times better than others. After heating, drying, or illumination, the current changes by tens of times. Such eminent scientists as Pierre Curie and E. Warburg explained the properties of crystals by comparing them either with accumulators connected in series within the crystal, or with polarization of a special kind.

Into this chaos I succeeded in bringing a certain clarity: the main cause of the anomaly proved to be space charges, becoming trapped in the crystal on impurities and concentrating in certain regions. By removing successively one region after another, I was able to determine the location of the charges. With the aid of probes, arran-

placed along the crystals, I was able to study precisely their arrangement and magnitude.

Of particular interest was calcite, where the charges are concentrated in a layer on the order of 0.001 mm near the cathode and create there a field of several million V/cm. This phenomenon was carefully investigated by us and led to a complete elucidation of the laws and mechanism of formation of concentrated polarization.

Taking volume charges into account made it possible to give a clear definition of the electrical conductivity of dielectrics and of the method for determining it. Thus the anomalies of dielectrics were reduced to the motion within them of electric charges—ions.

The capricious variability of the current under various influences was successfully reduced to an increase in the number of free charges under the action of light, thermal motion, and X-rays.

An enormous influence of negligible impurities was discovered, both on the magnitude of the current and on the accumulation of charges in a dielectric. By repeated recrystallization we succeeded in obtaining chemically pure crystals that gave a strictly definite electrical conductivity and showed no polarization.

In contrast to these assertions, based on direct experimental data, Smekal advanced another point of view, according to which all “sensitive” phenomena in crystals (including electrical conductivity) are determined by one and the same cause—defective sites of the crystal lattice. This is true with respect to mechanical properties, but incorrect with respect to the majority of electrical phenomena. A large discussion organized in Berlin in 1931 ended with Smekal’s statement that in electrical conductivity he had in mind only chemical inhomogeneities. Several years later, however, Smekal returned to his assertions and succeeded in spreading his views among many physicists, while his faithful pupils still consider them immutable truth. Comparing the entire body of known facts, I still come to the conclusion that impurities, and not accidental distortions, are fundamental in electrical conductivity. The study of dielectrics led to investigation of their electrical strength. One of the causes of breakdown proved to be the avalanche-like heating that occurs at certain voltages. This process of thermal breakdown was systematically studied by N. N. Semenov and A. F. Walter, and its theory was given by V. A. Fock. But at sufficiently low temperatures the breakdown mechanism is not connected with heating—this is electrical breakdown. Usually it was observed at fields of several thousand V/cm. In thin accumulations of charges—in calcite, and then in thin layers of glass and mica—we succeeded in observing, without breakdown, fields of millions of V/cm. The experiments seemed to confirm the complete analogy with gas breakdown, where the accumulation of new charges occurs under the influence of collisions of previously created electrons and ions with neutral molecules. This theory of breakdown indicated a path toward radical improvement of insulation by transition to thin-layer insulation. Experiments carried out

in connection with this theory, Siemens’s laboratory in Berlin fully confirmed our results on technical insulating materials. However, a repetition of the same experiments in our laboratories showed them to be erroneous. We succeeded in establishing sources of error in our former experiments that had not previously been noticed by anyone. Having eliminated them, we became convinced that on the average the strength does not depend on thickness, but the deviations from the mean values are greater the thinner the specimen. The reasons for the erroneous results of the measurements made at Siemens I still do not know.

In any case, it became clear that the route to improving insulation that proceeded from ionization by collision of ions or electrons promises no technical success for solid dielectrics. However, the systematic study of the phenomenon of breakdown and the work on more perfect insulation did not remain fruitless: new, very advanced insulating materials were developed—polystyrene and cellulose acetate. Methods were developed for obtaining dielectrics with a high dielectric constant (titanium dioxide and tricresyl phosphate), as well as methods of protection against the most dangerous, edge breakdown. Finally, a school of specialists in insulation was created, which sharply improved production and reduced rejects at the “Elektrosignal” plant in Voronezh, the Ordzhonikidze plant in Moscow, the Kharkov Electromechanical Plant, and the “Burevestnik” plant in Leningrad.

Semiconductors

The motion of ions in crystals has, in the main, been clarified. The motion of ions in amorphous bodies is being studied, and here too the basic regularities have been established.

But of special theoretical interest are the motion of electrons in the periodic field of a crystal and the conditions for the transition of electrons from a metal into a solid and liquid dielectric. From electronic conductors, or, as they are called because of their low conductivity, semiconductors, a direct path opens to an understanding of metals, on the one hand, and insulators on the other. The problems of breakdown and of improving insulation, apparently, can be solved only through the study of semiconductors. On the other hand, in recent years semiconductors have found wide technical application as rectifiers and photoelements. Therefore, since 1931 this problem has been taken up at the Ukrainian and Leningrad Physico-Technical Institutes. Since then conferences have been held regularly, embracing both a number of laboratories and a number of factories.

Here are the most important results of our work.

What had previously been established by us for ionic conductors proved to apply also to electronic ones: the current is made up of the current created by the fundamental lattice of the crystal and of the current determined by chemical impurities. Dependences of the electrical properties on impurity concentration, on temperature, on electric and magnetic fields, and on illumination have been established.

This rich factual material led to more definite conceptions of the mechanism of current. It turned out, for example, that in the great majority of semiconductors there is no simple transport of electrons by an electric field. All the properties rather resemble the motion of a positive charge. Indeed, Peierls and Bronstein studied a mechanism of current that satisfies these experimental data. This mechanism resembles the motion of positrons. In the current it is not an electron torn out by light or by thermal motion that is displaced, but the positive charge left behind by it.

The work of tearing out electrons, contrary to expectation, depends on the amount of impurities.

As in ionic crystals, in semiconductors an accumulation of volume charges formed by nonconducting layers has been discovered.

According to Pohl and Gudden, photoconductivity is not observed, under strong absorption, precisely where it would be expected; it is observed only at considerably longer wavelengths, where the absorption is already small. By making, however, a correct optical allowance for the electrical conductivity and the light absorbed in cuprous oxide, we eliminated this contradiction (the so-called “photoeffect riddle”) and showed that photoconductivity is determined by the absorbed light and is observed only within the absorption band.

When semiconducting crystals are illuminated, electromotive forces appear. Their properties gave rise to lively discussion and to a number of incorrect and contradictory assertions. Experimental analysis of this phenomenon led us to a theory that is in good agreement with experience. This theory assumes that in an illuminated crystal two current carriers are formed, equal and opposite in sign. A remarkable confirmation of their presence was the discovery by Kikoin and Noskov of a new photomagnetic effect—electromotive forces reaching the previously unprecedented magnitude of 20 V when cuprous oxide placed in a magnetic field is illuminated. The effect has been studied in detail and led to the discovery of still another secondary photomagnetic effect.

The views of wave mechanics proved to be a successful theoretical scheme for the study of semiconductors. Experience, however, introduces substantial additions to it (the sticking of electrons, the appearance of an entire system of impurity levels, localization of free places, etc.). The work is not yet finished, but the contours of a physical theory of semiconductors have already been outlined.

In the question of the rectifying properties of semiconductors, the decisive success that led to an explanation of these properties was achieved by the creation of rectifiers with artificial blocking layers made of various dielectrics, as well as by the still unfinished investigation of the behavior of semiconductors in strong fields. Contradictions in the explanation of photoelements with a blocking layer have also been eliminated, and their direct connection with photoconductivity has been established.

The workers of VEI, TsRL, “Svetlana,” and the People’s Commissariat of Communications took part in the discussion of the problems of semiconductors. The main producer of solid rectifiers, the Kozitsky plant, constantly consults on questions of production and has at its disposal the results of our measurements.

Ferroelectrics and Amorphous Dielectrics

Studies of crystals of Rochelle salt led to the discovery of a new phenomenon—an electrical analogue of ferromagnetism, named by I. V. Kurchatov ferroelectricity. The phenomena of saturation, hysteresis, and the Curie point with the corresponding electrothermal effects, as well as the value of the dielectric constant, reaching 200,000, not only bring these phenomena closer together, but also raise the more general question of energy transformations in solids.

The study of amorphous solid bodies, the basis of technical insulation, established general laws for electrical conductivity and dielectric losses, unambiguously determined by the solidification temperature. The processes of bonding, and the conditions of viscosity and flexibility of such bodies, have been clarified. Here a theoretical basis is being created not only for insulation, but also for one of the most advanced industries—the manufacture of plastics.

The Atomic Nucleus

The atomic nucleus, in contrast to the solid body, is a new element in the subject matter of the Physico-Technical Institute. Until 1932, when the nucleus became a central problem of physics, only one laboratory, that of Skobeltsyn, studied the properties of radioactive rays. The Wilson-chamber technique in a magnetic field developed here has now become the principal method for studying the nucleus and cosmic rays, a method that led, for example, to the discovery of positrons.

A new stage in nuclear physics is closely connected with the successes of high-voltage and vacuum technology. The appearance of rectifiers at 500,000 V led to the successful bombardment of the nuclei of lithium and other elements. In their turn, the problems of the atomic nucleus are before our eyes creating a new technology of millions of volts. The Ukrainian and Leningrad Physico-Technical Institutes are taking the liveliest part in this work, at the same time creating the material base for the study of the atomic nucleus.

However, even without this base, and without radioactive preparations, the Physico-Technical Institute has achieved great successes over the last two years. In a number of nuclear reactions the independence of the properties of the nucleus from the initial products and from the process of transition has been established. It has been shown that nuclear reactions branch along all theoretically possible paths. In some cases (for example Br) new isotopes have been discovered which contradict the general laws of their formation, indicating the possibility of the simultaneous emission of two neutrons or

for isomerism in the nucleus. It has been established that, for this type of nuclei, there is a definite interval of velocities of slow neutrons which especially often leads to a nuclear reaction. The distributions of electrons and positrons by velocity in natural and artificial radioactive processes have been measured with great precision. These new and reliable results substantially change the picture of β-decay and the energy balances of nuclear reactions. Indications have been obtained of new ways in which fast electrons interact with nuclei. Contradictions in the phenomenon of the interaction of the neutron with the proton have been eliminated by Kurchatov’s precise measurements.

A new result of outstanding fundamental significance was obtained by the Alikhanov brothers and Artsimovich only two days ago, on the question of the applicability of the laws of conservation of energy and momentum to the atomic nucleus and to energy transformations of the order of millions of volts. In the very last months this law was again called into question by Shankland’s work, which found, contrary to previous measurements, that in the Compton effect (in the collision of a photon with an electron) the photon of lowered frequency and the electron appearing as a result of the collision do not fly out simultaneously in those directions dictated by the conservation laws. If this observation were correct, then not only the conservation laws but the very existence of the photon would have to be rejected or substantially modified. The foremost authorities of America and Europe acknowledged the experimental persuasiveness of the experiment.* However, the detailed analysis to which Shankland’s experiments were subjected in our institute revealed very serious contradictions that cast doubt on this sensational result. We have set up control experiments in as pure a form as possible, and in a few months we hope to obtain a final answer.

Another, no less fundamental experiment has now already been completed, proving, on the contrary, the applicability of the conservation laws to each individual act, and not only to their aggregate results. When a positron combines with an electron, their electric fields, and with them their energy, are emitted in the form of electromagnetic waves. Since the electromagnetic radiation of a photon carries away, together with energy, an amount of momentum that the colliding positron and electron did not possess, the only possible outcome satisfying the conservation laws is the simultaneous emission of two photons of identical frequency in exactly opposite directions. The experiments of Artsimovich and the Alikhanov brothers did indeed confirm this conclusion. They placed photon counters in two opposite directions from the point of positron combination—

* In the very recent period (summer 1936), a number of new works by various investigators (Jacobsen, Bothe and Maier-Leibnitz, and finally Shankland himself) showed the incorrectness of Shankland’s first experiments and the full applicability of the conservation laws also to the process of scattering of photons by electrons. See on this in one of the forthcoming issues of Uspekhi. Ed.

trons with electrons. In this, in agreement with the calculation, they obtained 80 cases in which the photons arrived in both counters simultaneously, whereas under the same conditions there were only 23 accidental coincidences. When the counters were placed at a right angle, only 22 accidental coincidences were obtained, as was to be expected.

The experiments of the Alikhanovs and Arzimovich prove:

1) that the combination of a positron and an electron strictly obeys both laws—the conservation of energy and of momentum;

2) that the emission of electrons in the Compton effect in the counters occurs simultaneously with the collision of the photon (this indirectly refutes Shankland).

In combination with other already known facts, these experiments establish the validity of the laws of conservation of energy and momentum and render Shankland’s results extremely doubtful.

Several dozen published works, about ten new isotopes, and a number of new nuclear reactions characterize only in part the work carried out over the last two years.

The atomic nucleus is now, without doubt, one of the central problems of physics. Here the question of the relation among matter, electricity, and light is being resolved. Here the next stage is opening in the knowledge and mastery of the phenomena of nature, an indication of which is the “showers” of particles discovered by Blackett. Here, protected by energy barriers of millions of volts, are hidden enormous reserves of energy and possibilities for the transformation of elements. The path to these alluring prospects leads through the creation of high-voltage technology for millions and tens of millions of volts. Mastery of it will signify the beginning of a new stage in physics, and perhaps also in energetics.

PROBLEMS OF SOCIALIST TECHNOLOGY

In addition to purely physical investigations, I tried to pose the more general question of the tasks of socialist technology arising from contemporary physics. In a number of reports and articles I formulated about 30 more remote tasks in the fields of energetics, electrification, new technical materials, building construction, and agriculture, for which preliminary investigations should be undertaken. These included the photochemical, photoelectric, thermoelectric, and thermal utilization of solar energy; the use of northern cold; cheap sources of energy; cheap and light storage batteries and galvanic cells; heating by the cycle of refrigerating machines; windowless construction; rational forms of windows and heating systems; new materials to replace glass; transmission of energy by direct current; changes in the thermal, light, and water conditions in the soil; and others.

Along with interest in the formulation of problems of future technology, expressed in print and in numerous letters, my proposals were also subjected to newspaper criticism.

Of course, I did not manage at once to develop work in all 30 directions. For the use of solar energy in Samarkand, a Heliotechnical Institute was organized, which, with the participation of local physicists, achieved notable successes. Unfortunately, the institute has not survived. However, work is now continuing both in Samarkand and in Tashkent. Approximate calculations of machines using northern cold were made at the Heat-Engineering Institute by Prof. Vlasov and gave a favorable result. Since then, in America such machines have been tested experimentally. Detailed calculations of heating by refrigerating machines have appeared in the French and American technical literature. Windowless construction has also appeared. Work on light galvanic cells is under way in several laboratories of the Union.

The task of creating durable dirt roads was posed by D. L. Talmud and me at the Automobile-Road Institute, and there it yielded favorable results. The Physico-Technical Institute is engaged in the improvement of solid photoelements and thermoelements made from semiconductors. Even now it is possible to build thermoelements with an efficiency of 4% instead of 2%.

Work on photoelements has not yet passed beyond the stage of fundamental research. Work is also being conducted on new materials and on the transition to constant high voltage in the transmission of energy.

Of all the tasks mentioned, I consider the application of physics in agriculture especially important. With the beginning of broad collectivization, in 1932 the People’s Commissariat for Agriculture organized under my direction the Physico-Agronomic Institute. Here I managed to set up work on some of the 30 problems. F. E. Kolyasev will speak about the results obtained in the first 4 years.*

I shall mention only the film developed by D. A. Fedorov on the basis of acetylcellulose, which successfully replaces glass in hotbeds and greenhouses. This is one of the outcomes of work on thin-layer insulation. Lightness, great transparency in the visible and ultraviolet regions, absorption of infrared rays, and mechanical strength give this film a number of advantages over glass and ensure a higher temperature and humidity in hotbeds and greenhouses and, as a consequence, a considerably higher yield. The film acquires special significance for the North and for such regions as mountainous Tajikistan, the Caucasus, and places far from the railway. Another successful agronomic technique is the covering of soil with bitumen emulsion. Raising the soil temperature by 5–10°, preserving moisture, fixing sands and protecting them from erosion, and protecting plants from pests open up great prospects for this cheap and easily implemented

* Co-report by F. E. Kolyasev: “Physics in the Service of Socialist Agriculture,” see Proceedings of the Academy of Sciences of the USSR, Physical Series, No. 1–2, 1936.

measure. Finally, I shall note the results of V. P. Malyshev’s systematic study of the influence of individual regions of the spectrum on certain functions of the plant organism.

In joint work with physicists and lighting engineers, biologists found economically advantageous ways of multiplying the yield of vegetables and shortening the growing period. Thanks to this method, the area in which tomatoes can ripen now includes even our North.

Looking now over my notes and calculations on all the 30 problems that I put forward 5 years ago, I think that, with a few exceptions, all of them can also be successfully solved. With the end of the period of mastering Western technology, the time will come to place on the agenda these more remote and more difficult tasks. Experience will show how correctly I marked out the ways to solve them.

Scientific Results

Allow me now to turn to a characterization of all the work carried out by me and by the Physico-Technical Institute, and to outline the prospects for further activity. I await discussion of them with the greatest interest.

The principal result of our activity I consider to be the growth of Soviet physics and of its relative weight in world science. I think it will be no exaggeration to say that, instead of one of the last places, our physics has taken fourth place, and technical physics perhaps even third place. The Physico-Technical Institute alone has published more than 500 scientific investigations.

In the outline of my report, more than 40 scientific problems are listed that attracted serious attention and exerted a noticeable influence on the general development of physics. Among them there are also some in which the PTI proved, over the course of many years, to be a leader. Such, for example, are the problems of the mechanical properties of crystals, the electrical properties of dielectrics and partly of semiconductors, ferroelectricity and amorphous bodies, the spectra of γ-rays, electrons, and positrons. From the PTI there emerged such new directions as N. N. Semenov’s chain theory and D. L. Talmud’s linear adsorption.

There were also mistakes during this time, such as, for example, the avalanche theory of breakdown and thin-layer insulation. Some new facts did not immediately receive the correct explanation—for example, the X-ray limit of fluidity, the mechanism of the increase in the strength of salt in water, and jump-like deformation. But I shall not exaggerate the significance of the PTI’s work if I say that the rise of Soviet physics, in its very first decade, to one of the leading positions is due mainly to the work of the PTI. This assessment found reflection also in the fact that I am a member of 5 academies,

Technical Outputs

The “Outline of the Report” gives a list of those results of the work of the Physico-Technical Institute that have been used by technology. The most important of them are: the string method for measuring stresses, the radiographic method for studying castings and the structure of steel and alloys, the magnetic method for monitoring rotor casting, new insulating materials, protection of lines and high-voltage transformers, the theory of adhesives, agrophysical techniques and new methods of agrotechnical and biological measurements.

It must be noted that, from the entire system of the Physico-Technical Institute, which embraced physics and its applications, all the divisions of applied physics—electrophysical, heat-engineering, chemical physics, and telemechanics—were separated into independent institutes and therefore are not taken into account here. Of the whole vast scope of physics, optics is concentrated in the Optical Institute; low temperatures with their technical applications and high voltages have been assigned to the Kharkov Physico-Technical Institute; the physics of metals—to the Ural Institute; radiography—to the Dnepropetrovsk Institute. The Leningrad Institute, numbering only 50 staff members, concentrated its work on molecular physics and the atomic nucleus. A fuller picture of the participation of the Physico-Technical Institute in solving technical problems would be given by the work of all 12 institutes that make up the system of the Physico-Technical Institute, and not of the Leningrad Physico-Technical Institute alone.

The connection between physics and technology at the present moment appears to me in the following form. Most technical disciplines are broadly developed branches of physics. The physical phenomena that constitute the process of production were, in their time, reduced to a system lying at the basis of the given branch of technology. Subsequently, technology created from the branch an independent science, accumulated extensive experience, and brought it into a system. Only a few, the youngest branches of technology, have still preserved a close connection with physics and are developing with the participation of physical laboratories; such, for example, are the optical and radio-engineering industries. Here even the calculation of a new objective and mirror, or of a new radio-reception system, requires the participation of physicists. In the overwhelming number of other industries, the engineer knows his machines and their calculation far better than the physicist.

But, since technology deals with physical phenomena, their deeper study continually improves the production process. Sometimes physical discoveries make it possible radically to change the course of production; then physics creates a revolution in production. Such was the replacement of spark and arc, as generators of radio waves, by electron tubes; such are the flotation method, solid rectifiers, and photoelements. Not only these moments of technical revolution, but also, in general, the tempo of technical progress is determined by the level of physical knowledge. Technology, in turn, gives physics technical means and continually enriches its content, setting before it new problems and providing experience on a scale inaccessible to the laboratory. Finally, physics and technology

come into close contact in the control of production, in methods of measurement and observation.

These elements of the connection between physics and technology require definite organizational forms and a high level of Soviet physics. But it would be quite wrong to expect physicists to replace engineers and to set technical tasks, or to calculate and design machines. This is the direct task of the branch institutes, which must be closely connected not only with factories but also with physical centers.

The relation between physics and technology can best be compared with the relation of physiology to medicine. Only in isolated cases of new, still undeveloped methods of treatment do physiologists take part in them. In general, however, the development of medicine is carried out by physicians. Yet it is clear that the successes of medicine are determined by the development of physiology. Here, thanks to VIEM, a direct connection has been established between physiology and technology and medicine. No such connection of physics with branch institutes and factory laboratories exists. It can be carried out by the All-Union Academy of Sciences.

On the question of the relation of physics to technology there are many misunderstandings and outright errors. Some expect physics to be able to direct technology, to create new industries; others consider it useless for practice. It is often demanded that physics introduce its methods into technology almost by force, without taking account of engineering and economic factors. And only a few understand that the chief duty of physics is to respond to the demands of technology when they arise from the state of production, and to prepare new methods. The physicist is, in the main, a consultant to technology, not its leader.

During the first two five-year plans the demands made by technology upon physics were very modest. Therefore the role of physics, too, was small. Nevertheless, Soviet physics responded to the demands of technology and is ready for the more responsible role that awaits it in the coming years.

My confidence is based on the high scientific level of Soviet scholars and on the broad development of technical physics, already twice exceeding the volume of purely physical work. The growth of technical physics is truly astonishing and worthy of the great land of the Soviets. It did not exist at all before the Revolution. It now occupies one of the first places in the world.

The organization of Soviet physics and its connection with technology evoke respect and imitation abroad. The French Minister of Public Education twice sent official delegates to acquaint themselves with the organization of physics in the USSR as an example that France should follow.

The chief speaker at the recently concluded American congress on the application of physics in industry came to the pessimistic conclusion that, under the capitalist conditions of America, the role of physics is essentially reduced to teaching engineers physics.

I personally had occasion to take part in the work of the best factory laboratories in Germany: Siemens and AEG. There, too, I saw nothing substantially surpassing our applied physics. The same may be said of the laboratories of “General Electric,” “Metro-Vickers,” and “Westinghouse.”

I could perhaps point to only one laboratory where physics is used substantially better than in our country—the Philips laboratory in Holland and its work on new light sources and on radio engineering.

I have heard reproaches addressed to physicists that they have done little for technology. With equal right this reproach may be directed at engineers, who were unable to formulate their order to physics. There was no such order, and there was little desire to depart from foreign recipes in the direction of proposals from Soviet science.

This is understandable for the past period. But this will no longer be the case in 2–3 years.

What, then, must be demanded of Soviet physics so that it may cope with the tasks that lie ahead?

1. For advanced industry it is necessary, first of all, to have a highly developed physics.

2. A broad development of technical physics is needed, one capable of embracing all fields of application.

3. Physical knowledge and methods must be allowed to penetrate unhindered into the factories through branch institutes and factory laboratories.

Least of all has so far been done in the third, organizational direction, evidently because production workers do not yet feel the need for the participation of physicists.

Organization of Soviet Physics

A considerable share of responsibility for the development of Soviet physics falls upon me; therefore I consider it my duty to set before you the principal stages of my activity in this direction.

In 1918 Lunacharsky proposed that I, together with M. I. Nemenov, organize the X-ray and Radiological Institute, and I was entrusted with the physicotechnical and radium departments of the institute, which later became independent institutes under the same names. The nucleus of the new institute was formed by a group of my pupils, among whom I shall mention Semenov, Frenkel, Kapitsa, Lukirsky, Dorfman, Mysovsky, Schmidt, Kirpichev. They were joined by Chernyshev, Bursian, Glagolev, Wulf, Uspensky, and later Kirpichev, Davidenkov, Selyakov, Obreimov, Rozhansky, Frederiks, Andreev, Papaleksi.

The first 5 years were devoted to creating a scientific collective capable of posing and solving scientific problems. Twice a week meetings were held at which all the work of the staff was discussed in detail: first the general formulation of the problem, then the experimental and theoretical difficulties that became clear in carrying it out…

were, finally, subjected to extensive criticism of the conclusions of the completed study. In the first years I personally directed all the work of the institute and determined its topics. Then, from among my pupils, independent scientists emerged who set their own topics and began to create their own scientific schools. Now there are already extensive schools of the third generation: Valter, Leipunsky, Tartakovsky, Sinelnikov, Kurchatov, Kobeko, Kondratyev, Kurdiumov, Alikhanov, Gokhberg, Shubnikov, Kikonin, Yakutovich, and others.

We paid great attention to selecting the most capable young people from among the students of the Faculty of Physics and Mechanics, of which I was dean throughout this period. The best students, already in their third year, carried out research work at the PTI, without interrupting their studies. Knowledge of foreign languages was, and remains, a compulsory requirement.

Now, among the fourth and fifth generations of PTI physicists there are such serious scientists as Stepanov, Aleksandrov, Dukelsky, Alikhanyan, Kuvshinsky, Artsimovich, Bobikovsky, Kornfeld, and others.

The fact that Soviet physics lost its former provincial character and at once became an advanced sector of the physical front is due, to a considerable degree, to my frequent trips abroad and my close acquaintance with the work of all the leading institutes. Reports and lecture courses on the content of our scientific work I delivered in Germany, France, Holland, America, England, Czechoslovakia, and Belgium.

A considerable number of PTI staff members (more than 30) became acquainted with various scientific schools and methods of work during their trips abroad. Unfortunately, these trips have almost ceased in recent years, which greatly hampers the proper growth of young physicists.

From its very foundation, the task of the PTI was to build physics in the republic in such a way as to create a solid scientific base for future socialist industry. In order to attract all of Soviet physics to this task, in January 1919 we convened a congress of physicists, which adopted these guidelines for all laboratories.

An Association of Physicists was created, of which I was chairman from 1923. The Association regularly convened congresses of physicists; of these, the congress of 1928 placed on the agenda the creation of centers of physical science in various regions of the Union, and the congress of 1930—the task of planning physics. Conferences on semiconductors, the atomic nucleus, and X-rays brought together the corresponding workers throughout the Union.

Thus, from the very beginning of the revolution, physics was built and developed in an organized manner.

For the new tasks of physics, new personnel were also required, with different training. Therefore, already in 1919 I organized the Physico-Technical (now Engineering-Physics) Faculty, which

trained physicists who know technology. This faculty exerted a great influence on the plans and tasks of university physics faculties. The new physicotechnical institutes in Kharkov and Sverdlovsk also organized physicotechnical faculties in the local higher technical schools. Believing that the basic condition for successful scientific work is creative initiative and invention, I tried to draw worker-inventors into the work of the PhTI. A twice-repeated attempt has so far yielded no positive results, but normal paths have now been created for involving inventors in scientific work.

Instead of concentrating all physical work in Leningrad alone, I considered it the duty of Soviet physics to organize scientific centers in the most important republics and regions of the Union. This idea received the approval and powerful support of the government. The People’s Commissariat for Education created the Siberian PhTI in Tomsk. Thanks to the personal participation of Comrade Chubar, a first-class Ukrainian PhTI was created in Kharkov. By decision of Comrade Ordzhonikidze, the Ural PhTI was organized in Sverdlovsk. The PhTI in Dnepropetrovsk grew up. All these are not branches, but specialized physics institutes connected with local industry and, in their own fields of specialty, constituting all-Union centers. Such are the field of low temperatures in Kharkov, the physics of metals in Sverdlovsk, and phase transformations in Dnepropetrovsk.

The PhTI of 1918 has grown over the past 18 years into a system of 14 institutes and 3 higher technical schools, encompassing up to 1000 scientific workers, of whom about 100 may be counted among major independent scholars, including more than 30 doctors of physical sciences.

I regard the creation of a system of factory laboratories as an important step in fulfilling the task set for the PhTI. With the active assistance of M. A. Shatelen and M. V. Kirpichev, we surveyed all the factories of Leningrad and drew up a plan for organizing 111 factory laboratories. This plan was approved and put into effect by the Supreme Council of the National Economy, and was then extended to other regions of the Union.

Thanks to the fact that Soviet physics occupied a prominent place in world science, it became possible to create a Soviet journal in foreign languages, published by the Ukrainian PhTI in Kharkov. The journal is already counted among the first ten physics journals in the world.

The development of technical physics, whose chief center was the PhTI, led to the creation of a special journal of technical physics, first in Russian and then also in foreign languages. In its scope this journal surpasses the physics journal, and the foreign-language one has found a wide response abroad. In three of them I serve as responsible editor, and in the fourth—as chairman of the editorial council. In recent years, a very valuable addition to this system has been the “Reports of the Academy of Sciences of the USSR.”

Since 1933, on the initiative of the PhTI, a series of monographs has begun to be printed, comprising more than 50 books on the most topical problems of physics.

Tasks and Prospects

I have already had occasion to note that in the coming years Soviet physics is entering a particularly responsible period. It will have to provide answers to the most diverse questions of the construction of new technology. In order to be prepared for this task, it must make full use of the exceptionally favorable conditions that have been created for science in our country. To ensure the assistance of physics to production, it is first of all necessary:

1. To supplement the plan of scientific work by organizing research in all directions that are needed by industry, transport, communications, and agriculture. At present Soviet, and indeed world, physics encompasses the physical processes of by no means all branches of production.

2. To strengthen the physics groups in branch institutes, and to reinforce their ties and the ties of factory laboratories with physics institutes. More often to convene specialized conferences on particular questions, bringing together physicists, chemists, and research engineers.

To improve and deepen scientific work it is necessary:

1. To organize the scientist’s time better, so that he can concentrate all his attention and will on solving a scientific problem. This requirement is fully compatible with the scientist’s participation in the pedagogical process, but it presupposes a sharp reduction in the number of meetings and the concentration of work in one place. This applies first of all to the work of academicians.

2. It is desirable to increase substantially the number of trips abroad and invitations to foreign scientists.

3. It is necessary to organize the production of physical instruments and to supply institutes working in the field of the atomic nucleus with the corresponding quantity of radium.

4. To organize systematic scientific criticism of the printed works of Soviet physics, both in bibliographical journals and in oral discussion.

5. Both in teaching and in scientific work, to strengthen the connection between theory and experiment, to ensure a correct Marxist methodology and knowledge of the history of physics.

6. To improve the training of physicists by developing in them initiative, scientific criticism, and familiarity with the literature. To organize the systematic selection and verification of scientific workers, increasing their number.

7. The Physics Institute of the Academy of Sciences must attract to itself the largest Soviet scientists and concentrate its work on the key problems of contemporary physics.

8. The physics group of the Academy of Sciences, encompassing all leading Soviet physics, must ensure the implementation of the measures indicated. With the help of other groups of the Academy, and especially with the participation of the technical division of the Academy, all departments of technical physics, biophysics,

agrophysics, geophysics, chemical physics, astrophysics, and the application of physics in geology.

With regard to the Physico-Technical Institute, it seems to me necessary to develop in it that line of work which has determined its growth in recent years, ensuring a more definite influence from the demands of technology. We are concentrating our work on the problem of the atomic nucleus and the physics of millions of volts, on the elucidation of molecular forces, on questions of strength and plasticity, on electric charges in solid, liquid, and gaseous bodies, on new technical materials, and on the preparation of energy and agrotechnical tasks. The Academy of Sciences will include our work in the general scientific plan of socialist construction. As for myself personally, I consider it my duty at the present stage above all to conduct laboratory work and pedagogical work with young physicists. Alongside this work of mine in the Academy of Sciences, I shall do everything in my power to assist in the solution of the physical problems of socialist technology.

Scheme for the Construction of Soviet Physics in the Third Decade of the Social Revolution

1. All basic factories, large state farms, transport and communications centers must have laboratories carrying out production control, the examination of all inventive and rationalization proposals of workers and engineering-technical personnel, and their adaptation to the conditions of the given factory. Each such laboratory must include engineer-physicists, or must be directly connected with the nearest physics center. The more complex questions arising from its activity or from the work of the factory are passed on by the factory laboratory to branch or physics institutes.

2. Branch institutes of all branches of the national economy must have a physics nucleus composed of leading physicists well acquainted with the given production. Here cadres of technical physics and new fields of physics are formed.

3. In all large industrial centers and in the national republics there must be created physics institutes connected both with branch institutes and with higher educational institutions.

Where broadly developed industry is absent, this connection may extend to the formation of an institute within a higher educational institution. In the largest centers, independent institutes are needed, whose workers give special courses in the higher educational institution, and whose laboratories serve as a base for the training of physics cadres.

1. The central organ of Soviet physics is the Physics Group of the Academy of Sciences, including representatives of the largest physics institutes of the Union.

The Physics Group of the Academy of Sciences: 1) brings up for discussion the most important scientific results obtained in the USSR and abroad; 2) organizes work on the key problems of physics; 3) provides

supports the development of physical research that is necessary, or that may subsequently acquire importance, for the national economy of the Union, and organizes consultation on all questions of physics; 4) monitors the state of physical work and the teaching of physics in higher educational institutions, physical and branch institutes, hearing reports, sending instructors and lecturers to localities, and arranging for local workers to be sent to the appropriate central institutes and abroad; 5) organizes systematic conferences on specialized questions in those places where work on these questions is being conducted or where there is serious interest in them; 6) is obliged to monitor and to assist, with all the forces of Soviet physics, the raising of physical knowledge among broad circles of workers and collective farmers, especially among Stakhanovites and inventors, making extensive use of scientific and educational cinema, physical demonstrations, and museums.

1. The Academy of Sciences of the USSR, building socialist science, organizes its work in such a way as to ensure a real mutual connection among all its groups, including the Physical Group. The Academy of Sciences sets before Soviet physics tasks arising from the development of technology, from the needs of the national economy, from the heightened demands of everyday life, and from the requests of neighboring scientific disciplines, especially promoting the development of border areas of knowledge: all types of technical physics, biophysics, geophysics, agrophysics, etc.

ADDENDUM

The Most Important Scientific Results

Among the investigations of the Physico-Technical Institute that have had the greatest influence on the development of physics, one may name:

I. Mechanical phenomena. 1. Shifts and periodic ruptures under plastic deformation. 2. X-ray and optical analysis of it. 3. Separation of brittle and plastic ruptures and their theory. 4. Influence of the condition of the surface on strength and the statistical theory of strength. 5. Study of phase transformations in metals. 6. Investigation of impact.

II. Electrical phenomena. 1. Electrical conductivity of dielectrics. 2. Study of volume charges in them. 3. Thermal breakdown and breakdown of liquids. 4. Incomplete breakdown and the edge effect. 5. Ohmic and dipole losses in dielectrics. 6. Relation of electrical properties to the solidification temperature. 7. Ferroelectricity. 8. Electrical conductivity of semiconductors. 9. Photoconductivity, photo-electromotive forces, and the photomagnetic effect. 10. Artificial blocking layers. 11. Galvanomagnetic phenomena in liquid metals and their relation to superconductivity.

III. Electronic phenomena. 1. Distribution of photoelectron velocities. 2. Influence of monomolecular layers on the photoelectric effect. 3. Influence of temperature on electron diffraction. 4. Determination of the pattern of internal potentials. 5. Total internal reflection of X-rays from thin layers. 6. Spectrum of elementary braking radiation of X-rays. 7. Spectra of X-rays at potentials of several hundred thousand volts.

IV. The atomic nucleus. 1. Spectra of γ-rays. 2. Observations of cosmic rays in a Wilson chamber. 3. Verification of the relativistic theory of the Compton effect. 4. Emission of positrons by radioactive bodies. 5. Spectra of positrons and electrons. 6. Study of a number of nuclear reactions. 7. New isotopes. 8. Properties of slow neutrons.

V. Molecular phenomena. 1. Critical temperature of adsorption. 2. Excitation potentials of molecules. 3. Linear adsorption. 4. Strength of surface layers. 5. Reactions with branched chains. 6. Theory of chain reactions. 7. Properties of liquid crystals in electric and magnetic fields. 8. Mechanical oscillations of liquid crystals.

VI. Theoretical physics. 1. Theory of adsorption. 2. Theory of crystals. 3. Diamagnetism of metals. 4. Theory of semiconductors. 5. Theory of liquids. 6. Secondary quantization. 7. Two methods of Fock. 8. Quantization of the gravitational field.

VII. Monographs printed abroad. 1. Ioffe’s Physics of Crystals. 2. Ioffe’s Semiconductors. 3. Semenov’s Chain Reactions. 4. Frenkel’s Wave Mechanics. 5. Frenkel’s Electrodynamics. 6. Semenov and Walther’s Electrical Breakdown. 7. Kurchatov’s Seignette Electricity. 8. Kobeko’s Amorphous Bodies.

Technical Outputs of the Work of the Physico-Technical Institute

From the very beginning, the Physico-Technical Institute set itself as its chief task the preparation of the physical basis for the future socialist technology. Long before the beginning of the First Five-Year Plan, a laboratory of technical physics had been organized, in which the methods of contemporary physics began to be applied to major technical problems (the method of similarity and the physical study of heat transfer in heat engineering, the string and radiometric method in construction engineering, the theory of breakdown in insulation, ionization of gases for protecting low-voltage lines from high-voltage networks, the radiographic method for production control). An entire network of factory laboratories was organized. Thus, by the beginning of the First Five-Year Plan for the reconstruction of industry, there was a sufficiently solid scientific base.

During the First Five-Year Plan, a beginning was made in new directions directly connected with the tasks of technology (chemical physics for the chemical and food industries, acoustics), and during the Second Five-Year Plan—in metal physics (alloys and steels), amorphous bodies (plastics, insulation, adhesives), semiconductors (rectifiers and photoelements), low temperatures (the coke-benzol industry), telemechanics and automation, magnetic methods of control and casting of metals, and, finally, agrophysics.

One may list a number of results of the work of the Physico-Technical and Physico-Agronomic Institutes that have entered Soviet technology.

In the Field of Electrical Engineering

1. Protection of low-voltage networks from high-voltage lines (developed under the direction of acad. Chernyshev).
   Transferred to Glavsesrom and being carried out by the Svetlana plant.
   All networks of Lenenergo, Mosenergo, Donenergo, Uralenergo, the Caucasus, etc., have been equipped.

2. New insulating materials and corona breakdown (under the direction of A. F. Ioffe). Polystyrol is being used by Glavesprom for high-frequency insulation, acetylcellulose—for insulation of machines at “Elektrosila.”

3. Radio prospecting (under the direction of A. A. Chernyshev).

All instruments for electrical prospecting (with the exception of the Schlumberger method) were manufactured and designed at the Physico-Technical Institute and the Leningrad Electrophysical Institute.

1. Electric dust precipitators. The designs and specialist personnel have been transferred to the “Gazoochistka” trust.

2. The first image-transmission system was proposed by Acad. Chernyshev \(1 \tfrac{1}{2}\) years before Karolus. Many of its details are now being used by Glavelektrom.

In the Field of Heat Engineering

1. The method of modeling thermal devices.
2. Physical methods for studying working processes.
3. Analysis of heat transfer in individual sections.

In the Field of Mechanical Properties

1. The string method (developed by N. N. Davidenkov). It has found wide application: a) Dneprostroy—about 200 instruments have been installed in the dam; b) Dzora-GES—measurements: earth pressure, stress in concrete, elastic rebound, stress in the frame supporting the turbine generator; c) Gizeldonstroy; d) Baksanstroy; e) Ulbastroy; f) Dalzheldorstroy; g) Metrostroy—measurement of rock pressure on supports, stresses in vaults and in the concrete lining behind the shield; h) the dam on the Kalmyus River; i) the sewerage works in Leningrad (more than 30 dynamometers); j) Svir-stroy—earth pressure on the walls of the lock; k) Nivastroy; l) the Moscow–Volga Canal. The pressures of structures on foundations and the stresses within the structures themselves are measured; m) the Middle Volga—experimental caisson; n) Giproshakht—pressures on timbering in the coal mines of the Moscow region and the Donbass; o) numerous structures in Leningrad (wooden trusses, concrete vaults, pressure pipes, networks for stones, columns of factory buildings, etc.); p) numerous investigations by a number of research institutes (NATI, LIKS, NIIT, etc.).

2. Determination of internal stresses. The method of the Physico-Technical Institute is used by the Institute of Metals, the Institute of Metrology, the Izhevsk Plant, printing line-casting machines, and cast sleeves.

3. Transillumination and roentgenographic control of production. The “Bolshevik” plant, the Perm plant, the Mariupol plant, the Izhevsk plant, the Zlatoust plant, and a number of others.

The use of X-rays for heat treatment, especially of low-carbon steels, and for the control of matting.

1. Magnetic defectoscopy of casting. According to a report in the newspaper Tekhnika, it is used at the Lepse plant. It is being studied by the Central Institute of Metals.

2. Magnetic testing of transformer iron. It is being applied according to the method of the Ural Physico-Technical Institute by the Verkh-Isetsky plant.

Industrial Applications of Physics Originating from the Physico-Technical and Physico-Agronomic Institutes

1. D. L. Talmud’s microflotation method for sugar production. It is used in the production of 10,000 centners per day by the Gaisin Sugar Plant in Kiev Oblast.

2. The creation of artificial soil structures, begun on the initiative of D. L. Talmud.

In addition to the experimental fields of the Physico-Agronomic Institute, experiments in practical application have been set up in Kaunas (cotton-growing zone) on gray soils, in Vyritsa—on heavy clays, and in Torzhok (flax-growing zone)—on podzols.

1. Reinforcement of dirt roads, as a development of the preceding problem. The problem has been posed at the Road Institute and has yielded favorable results on experimental sections in Turkmenia, Gorky Krai, and near Leningrad.

2. Bituminous emulsion for changing the thermal and water regime of the soil and for fixing sands.

After a two-year experiment at the sand-desert stations in Chelkar and Repetek, in 1936 experiments are being carried out on a broad scale, over an area of up to 200 ha in various regions of Turkmenistan.

In addition, experiments with a bituminous film are being conducted in Batum, Sukhum, Crimea, Kherson, Kirovsk, and Igarka to combat erosion and to change the thermal regime.

1. Transparent film for protected soil. Experiments on the use of the film in hotbeds and greenhouses are being conducted on an extensive scale by the Institute of Vegetable Crops and the Institute of Subtropics.

2. Stimulation by artificial light of seeds and seedlings is passing in 1936 into a semi-industrial scale at the Institute of Vegetable Farming. In addition, experiments on the application of the method are being conducted in the Nikitsky Botanical Garden and in the Khibiny.

3. The growing of tree species under artificial light will be carried out in 1936 not only at the Physico-Technical Institute, but also at the Institute of Agroforestry Reclamation.

New Methods in Agronomy and Biology

1. Determination of soil moisture.
2. Measurement of radiative cooling.
3. Radiation thermometer.
4. Ultraviolet photometers.
5. Nephelometer.
6. Ion generator.
7. Pyranometer.
8. Special light sources and filters for plants.

The instruments developed by the Physico-Technical Institute are being manufactured for a number of institutes of VASKhNIL. Some of them, such as, for example, photoelements, have been produced in quantities of more than one hundred specimens; others (the nephelometer)—more than ten; still others (determination of soil moisture, measurement of radiative cooling, pyranometers, ultraviolet photometers) are being transferred, as they are manufactured, to other institutes.

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