The structure of karatavic acid

Conclusions Karatavic acid has been isolated from the resin of the roots ofFerula karatavica Rgl. et Schmalh; this is an ether of umbelliferone and a hydroxy acid C₁₅H₂₄O₃ probably having the humulane type of hydrocarbon skeleton. Two possible structural formulas—(I) and (II)—have been proposed for karatavic acid.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 5, pp. 283–287, 1968     

Heterocyclic nitro compounds

Ketones of the 3-nitro-5-R-1,2,4-triazole series react with hydrazoic acid in concentrated sulfuric acid to give triazolyl-substituted acetamides. Acid hydrolysis of the latter leads to 1-aminoalkyl-3-nitro-5-R-1,2,4-triazoles. Intramolecular cyclization with the elimination of HNO₂ and the formation of 2-nitro-5,6-dihydro-1H-imidazo[2,3-b]-1,2,4-triazole was noted in the case of 1-(2-aminoethyl)-3,5-dinitro-1,2,4-triazole.See [1] for communication XX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1271–1273, September, 1977.     

Application of separability and independence notions for proving lower bounds of circuit complexity

This note consists of two independent parts. In the first part the concept of an (m,c)-system for a set of linear forms is introduced, and a lower bound is obtained for the algebraic complexity of the computation of (m,c)-systems on algebraic circuits of a special form. In the second part, the notion of an -independent set of boolean functions is introduced and a lower bound is obtained for a certain complexity measure for circuits of boolean functions computing -independent sets. As a corollary it is shown that the standard algorithm for multiplying matrices or polynomials may be realized by a circuit of boolean functions in a way that is optimal with respect to a selected complexity measure.Translated from Zapiski Nauchykh Seminarov Leningradskogo Otdeleniya Mathematicheskogo Instituta im. V. A. Steklova Akad. Nauk SSSR, Vol. 60, pp. 38–48, 1976. Main results presented December 12, 1974 and May 29, 1975.The author would like to express his deep appreciation to A. O. Slisenko for his help.     

Quantum mechanics as relativistic statistics III. A relativistic particle in two-dimensional space-time

Statistics of random world lines in a fixed electromagnetic field are considered. The equation for a vectorj ⁱ is obtained. This vector describes the density of random world lines in a pure ensemble. It is shown that in the two-dimensional space-time this equation coincides with the Dirac equation to within the terms of the order of magnitude of (/L)² ( is Compton's wavelength,L is a typical length of the system).     

Temperature dependences of the flow and critical shear stresses of dispersion-hardening alloys

A study was made of the temperature dependences of the flow stress _0.1 (T) and of the critical shear stress _cr(T) of Cu-15% A1-(1–2)% Co, Cu-8% A1-(2–2.8)% Co, and Cu-4% A1–2% Co alloys containing noncoherent intermetallic particles. In the case of single crystals at temperatures 77–673° K there was a good agreement between the theoretically calculated values of the Orowan hardening and those found experimentally, so that the dependence _cr(T) was governed by the temperature dependence of the shear modulus G(T). For polycrystalline samples the usual dependence of the mechanical propertiesties on the grain size was not observed. At temperatures from 77 to 473–573°K the dependence _0.1 (T) was similar to the dependence G(T) and a good agreement was observed between the theoretically calculated dispersion hardening effects with those found experimentally. At temperatures T > 473–573°K the deformation was influenced greatly by grain-boundary glide, which enhanced the dependence _0.1 (T) compared with that expected theoretically.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 85–91, June, 1980.     

Kinetics of changes in the modulation period and in dispersion hardening in Cu-Ti-Me alloys

An investigation was made of the kinetics of changes in the flow stress _0.1, modulation period , and electrical resistivity in the course of ageing of Cu-Ti, Cu-Ti-Al, Cu-Ti-Zn, and Cu-Ti-Ga alloys. There were no dispersion hardening effects during the early stages of the precipitation, corresponding to the = const condition. An increase in _0.1. was observed during the stage of coagulation of the secondary phases. The increase in the flow stress was described using a theory of hardening by coherent particles of the new phase but it did not agree with the theory of hardening of alloys exhibiting spinodal precipitation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 81–87, May, 1980.     

Ferromagnetic resonance in media with an inhomogeneous saturation magnetization

The method of transition probabilities is used to calculate the line width of ferromagnetic resonance in a medium with an inhomogeneous saturation magnetization. It is shown that in addition to linear (with respect to the Fourier components of the function describing inhomogeneities) terms, the perturbation Hamiltonian must include also quadratic terms. The frequency dependence of the contribution of the porosity to H is fundamentally different from the frequency dependence of the magnetic anisotropy contribution. This anisotropy contribution H_a() decreases on increase in the frequency and has a maximum at = (2/3)_M, whereas the porosity contribution H_p increases on increase in the frequency and vanishes at = (2/3)_M.deceasedTranslated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp.48–52, December, 1980.     

Dispersion of the permittivity of high-resistance semiconductors

We consider the mechanism of macroscopic polarization of semiconducting plates owing to the interaction of free carriers with an impurity level, in which role the level of the residual impurity of compensated semiconductors may appear. This mechanism, in combination with the diffusion-drift mechanism of polarization, results in additional dispersion of the real () and imaginary () parts of the dielectric permittivity, this being particularly significant for semiconductors of thickness smaller than the screening length L_s of free carriers. The character of the behavior of and depends on the relation between the Maxwell relation time _M and the times of carrier capture: _c and ejection _e by an impurity center. For _cetm and (/L_s) _e/_c1 the dispersion of and is the same as for thick plates (/L_s1). For _{c m e} and (/L_s)_e/_c1 the () curve has a characteristic kink in the region 1/_e, indicating additional absorption associated with the ejection of carriers into the surface region.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 11–13, October, 1981.     

Mass-spectrometric investigation of the photoionization of diphenylmercury

Theoretical and Experimental Chemistry -     

Measurement of low-frequency noise in tunnel diodes

Conclusions Our studies have revealed that the spectral density of low-frequency current fluctuations in GaAs tunnel diodes can be described by the relation Wi(u, F)=f² (u)mF^–, where the nonlinear function f²(u) is not proportional to the rms of excess diode current. The flicker nature of the current noise in tunnel diodes derives from conductance fluctuations on the p-n junction, which occur in tunnel diodes as well as in low-noise transistors at frequencies ranging from near zero to a few kiloheriz and produce noise of almost the same absolute intensty in both kinds of devices.Leningrad Polytechnic Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 20, No. 5, pp. 777–784, May, 1977.