Direct writing of metal conductors with near-uv light

Deposition of micrometer-scale tungsten, molybdenum and platinum lines with the aid of the uv light from an argon-ion laser was investigated. Tungsten and molybdenum were deposited from their corresponding carbonyls and platinum from an acetylacetonate compound. High-quality metal conductors could be achieved for tungsten and platinum using a combined photolytic and pyrolytic, or hybrid, deposition scheme. The resistivity for these two deposited metals was approximately twice the bulk value. For molybdenum the deposition process was fast and dominated by the pyrolysis; the corresponding line resistivity was slightly higher than for the two other metals.     

The room-temperature decomposition of metastable phases precipitated in the Al-Zn alloys at 200 °C

The room-temperature decomposition of metastable phases in the Al-Zn alloys (from 25 to 50 wt. % Zn) was studied by the transmission electron microscopy and X-ray diffraction. Metastable phases, i.e. G.-P. zones, _R-and -phases, were grown at 200 °C and their decomposition into equilibrium -phase at 20 °C was investigated. Ageing times comprised 1 to 999 days.Both the decomposition mechanism and the rate of decomposition of coherent phases were found to be dependent on the particle sizes and their density reached at 200 °C. The local vacancy supersaturation around the -nucleus in a dense system of G.-P. zones leads to an enhanced growth rate of such nucleus and thus to the formation of one large -precipitate at the expense of several neighbouring G.-P. zones. The elastic stress field around this -particle promotes the further nucleation and growth of -precipitates and leads to their gradual spread throughout the matrix. The decomposition of intermediately sized _Rprecipitates results in the development of -precipitates of comparable sizes nucleated on the array of misfit dislocations at the periphery of _R-precipitates. The cooperative effect between neighbouring particles does not influence the decomposition of large _R-precipitated which split then into several smaller -particles. The rate of G.-P. zones or _R to -decomposition increases with the increasing sizes of transition precipitates and with the zinc content of the alloy. The kinetics of to -decomposition was found to be independent both on the annealing time at 200 °C and on the investigated alloy composition. This can be attributed to the constant density of misfit dislocations as nucleation sites for -precipitates along the -matrix interface and to the large mutual separation of -precipitates in all these alloys.In conclusion we would like to express our thanks to Doc. Dr. V.Syneek, CSc. for his valuable discussions and to Ing. V.íma for the preparation of Al-Zn alloys. Our thanks are also due to Mr. Z.iký for his help in the X-ray diffraction measurement and to P.Vyhlídka for the careful chemical analyses of the investigated alloys.     

The effect of microsegregation on the generation of dislocations in zinc single crystals

The applicability of Tiller's considerations on the production of dislocations is proved. The density of dislocations appearing during impurity microsegregation increases with increasing rate of growth as a consequence of the corresponding change in the effective distribution coefficient. The real value of C at the microsegregation boundaries is at least twice as great as the average value of the concentration of impurities in the crystal in question.

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. , , . C , .

     

Металлографические методы определепия нлотности дислокаци й В монокристаллах германия

, , . , .1) . .     

Nelson's symmetry and the infinite volume behavior of the vacuum inP(φ)2

LetH _l be the Hamiltonian in aP()₂ theory with sharp space cutoff in the interval (–l/2,l/2). LetE _l =inf(H _l ), (l)=–E _l /l, and let _l be the vacuum forH _l . discuss properties of (l) and _l . In particular, asl, there are finite constants <0 and such that (l), ((l)–)l, and hence (l)=+/l+o(l ^–1). Moreover exp(–c ₁ l) _{l 1}exp(–c ₂ l) forc ₁,c ₂ positive constants, where _{l 1} is theL ¹(Q, d₀) norm of ₁ with respect to the Fock vacuum measure. We also present a new proof of recent estimates of Glimm and Jaffe on local perturbations ofH _l in the infinite volume limit.Research sponsored by AFOSR under Contract No. F44620-71-C-0108.On leave from Istituto di Fisica Teorica, Universitá di Napoli and Istituto Nazionale di Fisica Nucleare, Sezione di Napoli.A. Sloan Foundation Fellow.     

Electronic processes andZ centres in NaCl and KC1 crystals

The paper gives the experimental results of the team-work study of coloured pure and Ca doped NaCl and KC1 crystals. The mechanism of the formation ofR centres by coagulation ofF centres and of the formation ofZ centres fromF centres, cation vacancies and Ca ions is discussed. An alternative model forZ ₃ centres is proposed. The possible connections between physical and chemical behaviour are indicated.

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Z- NaCl 1

NaCl KCl . R- F- Z- F-, Ca. Z ₃-. .

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This work was presented by the courtesy of Prof. R. Maurer at the Symposium on Color Centers, Corvallis, Oregon (1959).

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The authors wish to express their gratitude to K. Suk, K. Listoová and M. Javrková for carefully carrying out the measurements and I. Kunzlová and L. Nováková for preparing the crystals.     

The propagation of excitation energy in perturbed crystals

The process of the propagation of excitation energy in perturbed dielectric crystals with a weak bond between the atoms having zero permanent dipole moment is studied. It is shown that on certain assumptions this process of propagation can be regarded as the motion of a Frenkel exciton in the electrostatic field of the defect. Frenkel's exciton can be characterized in this case as a neutral polarizable particle having induced dipole moment equal to the change in the induced dipole moment of the crystal during the excitation of one of its atoms.

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, . , . .

     

СВЕТОСИЛА ЭЛЕКТРОНН О-ОПТИЧЕСКИХ СИСТЕМ

, . g - D, D', D ₄ , - , ' - , ' (). , - S, S ( ) - - 2 _k , 2 _k' () - - , ₂ , -      

Основные соотношени я длн построения механических селект оров нейтронов

, . , , . . , , .     

The theory of the spinning impact of imperfectly elastic bodies

The first theoretical solution is given of the spinning impact of an imperfectly elastic sphere on a rigid, imperfectly rough plane. The method of solution is based on the general static theory of the impact of rough bodies, elaborated by one of the authors in 1952 [5]. The problem leads to a non-linear differential equation, which can be solved only by an approximate numerical method. The results of the theory are in good agreement with the experiments carried out in 1947 [4].

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, . , 1952 . , . .

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In conclusion the authors thank Dr. Vaclav Goldbach, lecturer at our department, for valuable help in making the experimental apparatus and in carrying out the difficult measurements by the method described in section 3 of this paper. Our thanks also go to O. Brha for help in the graphical solution and drawing of the figures.     

ВОЗНИКНОВЕНИЕ КАТОД НЫХ ПЯТЕН И РАСПРЕДЕЛЕНИЕ ПЛОТ НОСТИ ТОКА В КАТОДНЫХ ПЯТНАХ СИЛНОТОЧНОГО ЭЛЕКТРИЧЕСКОГО РАЗР ЯДА

. , 760 mm . .

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Formation of cathode spots and current density distribution in cathode spots of short-time high-intensity electric discharge

The connection between the current density distribution in a spot and the vapour jets was found for a short-time high-intensity electric discharge by studying the structure of partial cathode traces and measuring the current density on the cathode. The variation of the current density on the spot with the current gradient was also found and the etching of the cathode surface with ionic bombardment at a pressure of 760 mm Hg was observed.

     

An attempt at a phenomenological interpretation of the influence of a polarizing field on piezoelectric resonators

The change in frequency of quartz piezoelectric resonators in a d-c electric polarizing field cannot be explained merely by a change in the dimensions of the resonator due to the polarizing field caused by the inverse piezoelectric effect and electrostriction. We are forced to admit that the elastic constants also change in a polarizing field. A phenomenological interpretation of the influence of a d-c electric polarizing field on the frequency of quartz resonators is proposed here, based on newly introduced quantities characterizing such a change. In conclusion it is shown in what way the quantities, on which the phenomenological theory is based, can be determined experimentally.

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, . , . , , . , , .

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The author would like to thank Dr. J. Tichý for carefully reading the paper, for valuable discussion and numerous remarks on style and subject matter, which greatly helped to improve the text. He is also indebted to V. Janovec, C. Sc., for some new aspects and the exceptional interest with which he reviewed the paper.     

A contribution to direct processes in the Co59(p,n) reaction forE p ∼ 6·5 MeV

Nuclear emulsions were used to study the energy spectrum and forward-backward asymmetry of neutrons from the Co⁵⁹(p,n) reaction forE _p 6·5 MeV. It was found that the decay of the compound nucleus makes a maximum contribution of 50% to the reaction yield. Energies of some excited states of the Ni⁵⁹ nucleus were also determined.

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Co⁵⁹(p,n) E _p 6,5 MeV

- Co⁵⁹(p,n) E _p 6,5 MeV. , 50%. , Ni⁵⁹.

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The authors would like to thank all those who helped in this work, particularly all members of the cyclotron group of the Nuclear Research Institute of the Czechoslovak Academy of Sciences, who so willingly helped with the irradiation, and H. Koutová from the Faculty of Technical and Nuclear Physics, who carefully measured the emulsions. Our thanks are also due to R. Krejová from the Faculty of Technical and Nuclear Physics for developing the emulsions and J. Kopecký from the Nuclear Research Institute for providing the cobalt target.     

The basic equations of the dynamics of the continuous distribution of dislocations I. General theory

The basic equations of the dynamics of the continuous distribution of dislocations analogical to Maxwell's equations are derived in a series of papers I, II, III. The analogy of the elastic and electromagnetic fields is analyzed. In part I the basic equations of the continuous distribution of dislocations are derived for the dynamic case (especially for small deformations and for the Poisson ratio equal to zero in a continuum, infinite with respect to space and time, from the variational problem by means of the formal apparatus of the special theory of relativity.

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I.

, . . , , .

     

Spectral composition of thermoluminescence of coloured NaCl crystals

The paper gives the experimental results of studying the spectral composition of thermoluminescence in the different maxima in photo-chemically coloured pure NaCl crystals or NaCl-crystals containing Cu in different concentrations.

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NaCl

NaCl .

     

The scattering of waves by a periodic surface

The paper derives a general formula for the scattering of electromagnetic (or sound) waves from a periodic, perfectly conducting (or perfectly rigid) surface. No restrictions are imposed on the angle of incidence, the size of the surface or the degree of roughness. Except for the basic Kirchhoff approximation, the method is exact. The results confirm, generalise or correct special cases obtained by more complicated methods.

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, ( ) . , . . , , .

     

РАДИОМЕТРИЯ В ГЕОФИЗ ИКЕ

cmambe ome, - . - .     

The interaction of foils activated by thermal neutrons

The interaction of foils lying in a plane during their activation by thermal neutrons has been calculated. Numerical values of functions are listed, which can be used in calculations, especially for graphite. The interaction was measured in the graphite column of the VVR-S reactor.

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, , . , , . VVR-S.

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We thank J. Frytacký, T. Kania and V. ervenka for their help in the numerical calculations and measurements.     

Domain structure of cobalt whiskers

An experimental investigation is made into the domain structure of cobalt whiskers by the colloid technique. A new type of domain structure was found; the width of the domains is studied as a function of the thickness of the whisker. This dependence follows a two-thirds power law and does not agree with existing theories which predict a half power law.

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. . , .

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In conclusion the authors wish to thank V. Janovec and F. Kroupa for valuable remarks and A. Tahalová for help in growing the whiskers.     

Влияние катодной обл асти на динамические свойства тлеющего разряда в во дороде

. . , , I-om 1957 .