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排序方式: 共有103条查询结果,搜索用时 343 毫秒
1.
A shock and subsequent rarefaction wave shock-wave system in a plane supersonic inviscid non-heat-conducting gas flow is considered. An exact analytic solution of the problem of determining the intensities of the waves leading to extreme values of the gasdynamic variables (static pressure, temperature, etc.) behind the wave is found using Lagrangian multipliers. These systems are related to the optimal ones [1, 2]. The parameters of the problem are the free-stream Mach number, the specific heat ratio, and the total flow turning angle in the wave system. Analytic solutions determining the boundaries of monotonic and nonmonotonic behavior of the gasdynamic variables behind the system are presented. The effect of the specific heat ratio on the dimensions of the domains of existence of the optimal waves is investigated.St. Petersburg. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 142–150, July–August, 1996. 相似文献
2.
Supersonic flows of gas in the vicinity of the bottom region known as flows with sudden expansion have been considered. On the basis of extensive experimental studies, authors have proposed a complete classification of flow regimes: stationary, oscillating, and transient. Hysteresis of the regimes change at total gas pressure increasing and decreasing in front of the nozzle has been found. Typical shock-wave configurations emerging at the jet flowing in a channel at different modes have been determined. The type of shock-wave structure and the nature of interaction of the mixing layer of a jet with the wall or reverse flow flowing into the channel from ambient medium determine the appropriate mode. Combination of physical and numerical experiment with bottom pressure calculation according to the developed semi-empirical model have revealed new flow regimes that were not studied earlier. 相似文献
3.
Z. A. Savel’eva S. A. Popov R. F. Klevtsova L. A. Glinskaya E. M. Uskov A. V. Tkachev S. V. Larionov 《Russian Chemical Bulletin》2009,58(9):1837-1840
A complex ZnLClb2 (L is 2-(3,5-dimethylpyrazol-1-yl)-4-methylquinoline) was synthesized. According to X-ray diffraction data, the Znp2+ ions in mononuclear molecules of the obtained complex coordinate two N atoms of the bidentate chelating ligand L and two
Cl atoms. The coordination polyhedron Cl2Nb2 represents a distorted tetrahedron. In solid state at 300 K, the ligand L exhibits weak photoluminescence in the visible
spectral range. The complex ZnLClb2 exhibits bright blue photoluminescence. 相似文献
4.
É. M. Belenov P. G. Kryukov A. V. Nazarkin A. N. Oraevskii A. V. Uskov 《Journal of Russian Laser Research》1989,10(2):145-156
Some results are reported on coherent propagation of optical pulses. In particular, a solution is presented of the Maxwell-Bloch equations for the case of amplification of high-power pulses with varying carrier frequency but with constant number of photons in the pulse.Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow. Translated from Preprint No. 211 of the Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1988. 相似文献
5.
Triple shock-wave configurations in steady supersonic flows of an inviscid perfect gas are considered. Triple configurations
with special intensities of shock waves and extreme ratios of various flow parameters behind these configurations are determined.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 39–53, July–August, 2006. 相似文献
6.
7.
S. V. Larionov Z. A. Savel’eva R. F. Klevtsova L. A. Glinskaya E. M. Uskov M. I. Rakhmanova S. A. Popov A. V. Tkachev 《Journal of Structural Chemistry》2011,52(3):531-537
Using the single crystal X-ray diffraction data (150 K, Bruker X8 Apex CCD autodiffractometer, MoK
α radiation), the crystal structure of the [Cd2L2Cl4]·CH2Cl2 (L = pyrazolylquinoline, the derivative of monoterpenoid (+)-3-carene) compound is determined. Crystals are monoclinic, unit
cell parameters are: a = 10.7005(4) ?, b = 16.8491(4) ?, c = 11.9658(4) ?, β = 93.308(1)°, P21 space group. The structure is formed from discrete acentric molecules of a binuclear [Cd2L2Cl4] complex and uncoordinated CH2Cl2 molecules. The Cd2+ ions coordinate N atoms of bidentate chelating ligands L, which leads to the closure of two five-membered chelate CdN3C rings. The coordination sphere of Cd atoms also includes three Cl atoms (two bridging and one terminal), consequently, two
CdCl3N2 coordination sites and a Cd2Cl2 metal ring are formed. The Cl3N2 polyhedra have the form of distorted tetragonal pyramids. The CH2Cl2 molecules located in the channels formed by the complexes are linked with them by weak H-bonds. The excitation spectra of
L and the CdLCl2 compound contain bands with λmax of 352 nm and 360 nm respectively. At 300 K and λexcit 350 nm, in the photoluminescence spectrum of L a rather intense broad split band with λmax 372 nm and 386 nm is observed. The photoluminescence spectrum of the CdLCl2 compound contains a broad band with λmax 418 nm. The photoluminescence intensity of this compound is significantly lower than that of L. 相似文献
8.
9.
The temperature dependence of the dynamic modulus of elasticity E and the loss tangent tg has been investigated for polymethylmethacrylate (PMMA) and polystyrene (PS) with different contents of kaolin filler (K), in the glassy state and in the region of incipient devitrification. It is concluded that supermolecular reinforcing structures appear in filled polymers in which the intermolecular forces are sufficiently strong.Mekhanika Polimerov, Vol. 3, No. 5, pp. 854–857, 1967 相似文献
10.
A new method is discussed for the solution of many-level charge-exchange problems. The results provide the distribution of the final electronic states over the angular quantum numbers in analytical form. The obtained Z oscillations (Z is the ion charge) of the cross sections are found to be in good agreement with recent experimental data. 相似文献