Guanidine hydrochloride aminomethylation with formaldehyde and simplest amino acids

Aminomethylation of guanidine hydrochloride with aqueous formaldehyde and simplest amino acids depending on the reagents ratio results in bicyclic hydrochlorides (1: 4: 2) or tricyclic iminium chlorides (1: 6: 3) that in their turn may be converted into internal salts: zwitter-ions or betaines respectively.     

Hydroxyl-containing imidazolium ionic liquids

A number of imidazolium ionic liquids with bis(trifluoromethylsulfonyl)imide anion containing a ω-hydroxyalkyl substituent of different lengths in the cation (n_С = 2–8) were synthesized. The properties of the obtained liquids were investigated by DSC, TGA, IR, and NMR spectroscopy. Their thermal stability was studied; melting points, viscosity, and volatility in vacuum were measured. The possibility of using synthesized ionic liquids as heat carriers under high vacuum conditions is demonstrated.     

Thermodynamic modeling of the deposition of Si—C—N films from the gas phase during the decomposition of organosilicon compounds

Thermodynamic modeling of the process of chemical vapor deposition (CVD) of SiC_x and SiC_xN_y films from the gas phase was carried out using organosilicon compounds (EtN(SiMe₃)₂, PhN(SiMe₃)₂, and PhSiMe₃) at reactor pressures of 0.01 and 10 Torr in the temperature range of 500–1200 K. It was established that regions of existence of two phase complexes, namely, SiC + Si₃N₄ + C and SiC + C, were present on the CVD diagrams calculated for the EtN(SiMe₃)₂—He and PhN(SiMe₃)₂—He systems. The CVD diagrams calculated for the EtN(SiMe₃)₂—NH₃, PhN(SiMe₃)₂—NH₃, and PhSiMe₃—NH₃ systems have regions of existence of three phase complexes, namely, Si₃N₄ + C, SiC + Si₃N₄ + C, and SiC + C. The composition of the obtained silicon-containing films was calculated.     

Synthesis and study of the azide-tetrazole tautomerism in 2-azido-4-(trifluoromethyl)-6-R-pyrimidines (R = H, 4-ClC<Subscript>6</Subscript>H<Subscript>4</Subscript>)

Azide-tetrazole equilibrium in azidopyrimidines bearing trifluoromethyl group on the example of 2-azidopyrimidines has been studied. The latter were synthesized via nitrosation of 2-hydrazino-4-trifluoromethylpyrimidine and reaction of NaN₃ with 4-trifluoromethyl-2- chloro-6-(4-chlorophenyl)pyrimidine. The tautomeric equilibrium 5-trifluoro methyl tetrazolo[1,5-a]pyrimidine ? 2-azido-4-trifluoromethylpyrimidine was observed in the absence of solvent and in DMSO-d₆ solution, whereas in CDCl³ only an azide form exists. For 2-azido- 4-trifluoromethyl-6-(4-chlorophenyl)pyrimidine, only an azide isomer was detected in CDCl³ solution, and in DMSO-d₆ solution it is in equilibrium with 5-(trifluoromethyl)-7-(4-chlorophenyl) tetrazolo[1,5-a]pyrimidine (the tautomer ratio is 99 : 1). Thermodynamic and kinetic parameters of 5-trifluoromethyltetrazolo[1,5-a]pyrimidine ? 2-azido-4-trifluoromethylpyri midine tautomeric rearrangement in DMSO-d₆ for 5-trifluoromethyltetrazolo[1,5-a]pyrimidine were determined using the exchange spectroscopy (EXSY) technique.     

тЕМпЕРАтУРНАь жАВИс ИМОсть МОДУлЕИ УНгА сплАВОВ АлУМИНИь с цИ НкОМ И ЕЕ ВлИьНИЕ НА кОгЕРЕНтНУУ ДИАгР АММУ сОстОьНИь

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Temperature dependence of the young's modulus of the Al-Zn alloys and its influence upon the metastable coherent phase diagram

The paper describes the measurements of the temperature dependence of Young's modulus for several Al-Zn alloys. The moduli were measured by the method of a composite oscillator at resonance frequencies of about 100 kHz. When decreasing the temperature from the state of homogeneous solid solution, the undercooling phenomena cause a hysteresis effect. Young's modulus decreases approximately linearly with increasing atomic fraction of zinc at 390C. The determined temperature and concentration dependence was used for thermodynamic calculation of the form of metastable coherent solubility gaps by which the separation of the solid solution into coherent zones can be described.

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B. K. Kardaev, S. P. Nikanorov,A. F. Ioffe Physico-Technical Institute, Acad. Sci. U.S.S.R., Politechnieskaja 26, Leningrad K- 21, U.S.S.R.

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J. Laek,Institute of Solid State Physics, Czechosl. Acad. Sci., Cukrovarnická 10, Praha 6, Czechoslovakia.     

О множителе Вейля для сходимости сумм Рима на

The paper is dedicated to the problem of almost everywhere convergence of the Riemann quadrature sums depending on one or two parameters for functions which are, in general, nonintegrable in the sense of Riemann. In particular, the following assertion is proved.     

О метрических свойст вах особых множеств г оломорфных функций нескольких п еременных

LetG be a domain inC ⁿ ,EG, mes E=0 for (r)=r ^2n–1(r), where (r) is a nondecreasing non-negative function (r>0). Iff(z) is holomorphic inGE and (,f, GE)(), C=const, thenf(z) is holomorphic inG.The impossibility of the relaxation of the stipulations on () and(r) is also established.The statement above is a corollary to a more general result about the representation of a holomorphic function from a certain class in the form of an integral with respect to -measure, extended over the set of singular points of the function.     

О росте вдоль прямой ц елых функций экспоне нциального типа с заданными нулями

The following result is proved. Let=_n} be a sequence of complex numbers with ¦Re _n¦¦ _n ¦, >0, and letg be an entire function of exponential type with a sequence of zeros which satisfies the same condition. There exists an entire function of exponential typef0 such thatf()=0 and ¦f(iy)¦¦g(iy)¦,yR, if and only if there exists a constantM such that for all numbersr andR, 0rR<>, we have

Spin and pseudospin symmetries of the Dirac equation with shifted Hulthén potential using supersymmetric quantum mechanics

In this paper, we obtain approximate analytical solutions of the Dirac equation for the shifted Hulthén potential within the framework of spin and pseudospin symmetry limits for arbitrary spin–orbit quantum number κ using the supersymmetry quantum mechanics. The energy eigenvalues and the corresponding Dirac wave functions are obtained in closed forms.