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In this paper, experimental results of the investigation of the periodic structure on thermoelectric semiconductor Cu2Se are presented. Periodic structures were formed on surfaces of semiconductors due to multi-beam interaction of Q-switched Nd:YAG laser, which was operated in the lowest order of Gaussian mode and pulse duration 7 ns. Surface temperature evolution and transient reflectivity are studied during laser treatment. Creation of Cu islands in the maximal intensity of interference pattern was found. 相似文献
2.
Diaper CM Sutherland A Pillai B James MN Semchuk P Blanchard JS Vederas JC 《Organic & biomolecular chemistry》2005,3(24):4402-4411
Aziridine analogues of diaminopimelic acid (DAP) have been prepared stereoselectively for the first time and evaluated as inhibitors of DAP epimerase. (2R,3S,3'S)-3-(3'-Aminopropane)aziridine-2,3'-dicarboxylate was synthesised and shown to be a reversible inhibitor of DAP epimerase with an IC(50) value of 2.88 mM. (2S,4S)- and (2S,4R)-2-(4-Amino-4-carboxybutyl)aziridine-2-carboxylic acid (ll-azi-DAP and dl-azi-DAP ) were made as pure diastereomers, and both were shown to be irreversible inhibitors of DAP epimerase. ll-Azi-DAP selectively binds to Cys-73 of the enzyme active site whereas dl-azi-DAP binds to Cys-217 via attack of sulfhydryl on the methylene of the inhibitor aziridine ring. These observations are consistent with the two base mechanism proposed for the epimerization of ll-DAP and meso-DAP by DAP epimerase. 相似文献
3.
A simple method is proposed for increasing the accuracy of computation of the eigenvalues of elliptic operators, which does not require high-order accurate schemes.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 63, pp. 63–68, 1987. 相似文献
4.
A. R. Semchuk 《Journal of Mathematical Sciences》1992,58(5):412-417
We consider the eigenvalue problem for the operator defined in a rectangle whose vertical left-hand side coincides with the z-axis. A difference scheme is constructed by an integrointerpolation method. An error bound is obtained for the simple eigenvalue of the difference analog in weighted generalized spaces W
2
2
and W
2
3
.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 58, pp. 29–35, 1986. 相似文献
5.
Thermodynamic and transport properties of mesoscopic conductors are strongly influenced by the proximity of a superconductor: an interplay between the large scale quantum coherent wave functions in the normal mesoscopic and the superconducting region, respectively, leads to unusual mechanisms of quantum interference. These manifest themselves in both the mean and the mesoscopic fluctuation behaviour of superconductor-normal-metal (SN) hybrid systems being strikingly different from those of conventional mesoscopic systems. After reviewing some established theories of SN quantum interference phenomena, we introduce a new approach to the analysis of SN mesoscopic physics. Essentially, our formalism represents a unification of the quasi-classical formalism for describing mean properties of SN systems on the one hand, with more recent field theories of mesoscopic fluctuations on the other hand. Thus, by its very construction, the new approach is capable of exploring both averaged and fluctuation properties of SN systems on the same microscopic footing. As an example, the method is applied to the study of various characteristics of the single particle spectrum of SNS structures. 相似文献
6.
O. Yu. Semchuk L. G. Grechko L. Yu. Kunitskaya O. I. Gichan 《Journal of Applied Spectroscopy》2009,76(5):692-698
The scattering indicatrix of electromagnetic waves for different types of rough surfaces and angles of incidence is calculated
using the Kirchhoff scalar theory. The rough surfaces are modelled by a two dimensional Weierstrass function. The scattering
index for a rough surface with a fractal relief is found to have a complicated structure with intensity bursts in directions
quite far from the direction of mirror reflection. 相似文献
7.
Vakhula Ya. I. Yashchishin I. N. Semchuk O. R. Novosad P. V. 《Russian Journal of Applied Chemistry》2002,75(7):1185-1187
X-ray phase analysis was applied to study the phase composition of products formed in reaction between components of silicophosphate solutions obtained on the basis of potassium water glass. The temperature ranges of phase transformations of chemical compounds, occurring in thermal treatment of gels of various compositions, were established. 相似文献
8.
Vakhula Ya. I. Yashchishin I. N. Vasiichuk V. A. Romaniv A. S. Semchuk O. R. 《Russian Journal of Applied Chemistry》2001,74(12):1990-1993
Conditions for obtaining stable colloid solutions for synthesis of alkali-silicate glass coatings based on lithium, sodium, and potassium liquid glass were studied. The influence of the solution pH and the nature and concentration of liquid glass on the gel formation was established. 相似文献
9.
O.V. Pylypova A.A. Evtukh P.V. Parfenyuk I.I. Ivanov I.M. Korobchuk O.O. Havryliuk O.Yu. Semchuk 《Opto-Electronics Review》2019,27(2):143-148
In our studies the absorption, transmittance and reflectance spectra for periodic nanostructures with different parameters were calculated by the FDTD (Finite-Difference Time-Domain) method. It is shown that the proportion of reflected light in periodic structures is smaller than in case of thin films. The experimental results showed the light reflectance in the spectral range of 400–900 nm lower than 1% and it was significantly lower in comparison with surface texturing by pyramids or porous silicon.Silicon nanowires on p-type Si substrate were formed by the Metal-Assisted Chemical Etching method (MacEtch). At solar cells with radial p-n junction formation the thermal diffusion of phosphorus has been used at 790 °C. Such low temperature ensures the formation of an ultra-shallow p-n junction. Investigation of the photoelectrical properties of solar cells was carried out under light illumination with an intensity of 100 mW/cm2. The obtained parameters of NWs' solar cell were Isc = 22 mA/cm2, Uoc = 0.62 V, FF = 0.51 for an overall efficiency η = 7%. The relatively low efficiency of obtained SiNWs solar cells is attributed to the excessive surface recombination at high surface areas of SiNWs and high series resistance. 相似文献
10.
A. R. Semchuk 《Journal of Mathematical Sciences》1994,69(5):1285-1288
A homogeneous difference scheme is considered for calculating the eigenvalues of magnetic and electrical modes of a multilayer dielectric resonator in a cylindrical screen. Numerical results given for prototype examples and an applied problem are compared with experimental data.Chernovtsy University. Translated from Vychislitel'naya i Prikladnaya Matematika, No. 67, pp. 37–42, 1989. 相似文献
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