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排序方式: 共有185条查询结果,搜索用时 359 毫秒
1.
Takayuki Yamanaka Hideki Fukano Ken Tsuzuki Munehisa Tamura Ryuzo Iga Matsuyuki Ogasawara Yasuhiro Kondo Tadashi Saitoh 《光学学报》2003,23(Z1)
A comprehensive analysis of multi-quantum-well electroabsorption modulators buried with semi-insulating (SI)-InP is presented. We quantitatively demonstrate that suppression of Zn diffusion into the burying and optical core layers plays a key role in high-speed and high-extinction operation. 相似文献
2.
Takafumi Ohta Kohji Shikinami Yukiyo Iga Shoji Takitani 《Fresenius' Journal of Analytical Chemistry》1990,336(5):385-388
Summary Chelex resins in several metal forms were tested for selective uptake of o-nitrosonaphthols and o-nitrosophenols from aqueous solution. Cu-Chelex was the most efficient resin over a wide pH range, and the taken-up nitroso compounds were effectively eluted with concentrated ammonia: acetonitrile (4:1, v/v) after washing the resin with acetonitrile to eliminate non-specific binding. The upper and lower limits of uptake capacity of the resin for 1-nitroso-2-naphthol were 0.5 mol/100 mg and 1.25 mol/100 mg, respectively. A preliminary recovery experiment using urine and cucumber juice showed that Cu-Chelex would be useful for screening of o-nitroso derivatives of phenolic substances in complicated samples such as biological fluids and foods. 相似文献
3.
4.
S. V. Polschikov P. M. Nedorezova T. V. Monakhova A. N. Klyamkina A. N. Shchegolikhin V. G. Krasheninnikov V. E. Muradyan A. A. Popov A. L. Margolin 《Polymer Science Series B》2013,55(5-6):286-293
New composite materials based on isotactic PP and fullerene were prepared via in situ polymerization with the use of an isospecific metallocene catalytic system. The stress-strain properties, thermophysical characteristics, and reactivities of composites in reactions of high-temperature decomposition, oxidation, and chemiluminescence were studied. The appreciable effect of fullerene on the thermal oxidation and crystallization behavior of composites (an increase in the crystallization temperature by 10 K) was found. It was shown that the protective inhibitory effect of fullerene in PP oxidation reactions is due to the interaction of fullerene nanoparticles with peroxy macroradicals. 相似文献
5.
Hovsepyan T. R. Hakobyan M. R. Muradyan R. E. Nersesyan L. E. Aharonyan A. S. Danielyan I. S. Minasyan N. S. Harutyunyan A. A. 《Russian Journal of Organic Chemistry》2020,56(12):2137-2142
Russian Journal of Organic Chemistry - While developing new approaches to the design of biologically active compounds based on 1,2,4-triazole, a number of new hydrazones containing... 相似文献
6.
The effect of inelastic scattering on the electron reflection in multi-quantum barriers (MQBs) has been examined using the damped resonant tunnelling model for the first time. The electron reflectivity in the virtual barrier region for unstrained GalnAs/InP MQB deteriorates below 100% by about 10% for phase relaxation time of 0.22ps. We propose a strain-compensated GalnAs/GalnP MQB which not only has virtual barrier 4 times as high as that of an unstrained MQB, but whose reflectivity deterioration is reduced to less than 5% in comparison with 10% for unstrained MQB for the same phase relaxation time. We have also successfully grown a Ga0.25In0.75As (1.5% compressive) well/Ga0.25In0.75P (1.2% tensile) barrier short-period superlattice with six wells by chemical beam epitaxy, which exhibits the possibility of fabrication of the strain-compensated MQBs. 相似文献
7.
The main absorption site of ethyl 2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)phenyl]propionate (AL-294) in rats was the upper portion of the small intestine. Both AL-294 and AL-294 acid (2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)phenyl]propionic acid), a hydrolyzed form of AL-294, were absorbed in a smaller quantity under the bile fistula condition (pancreatic juice and bile were excluded). Compared with the absorption of AL-294 as an emulsion under the sham operation condition, the absorption of AL-294 as the emulsion decreased under the condition where only pancreatic juice was excluded. The bioavailability under this condition was very similar to that under the bile fistula condition, whereas the absorption of AL-294 acid did not decrease when the pancreatic juice was excluded. From these results, the absorption mechanism of AL-294 is considered as follows: AL-294 was hydrolyzed to AL-294 acid by lipase in pancreatic juice, then AL-294 acid was solubilized with bile salts to form mixed micelles in the intestinal lumen. AL-294 acid from this form was easily absorbed into the systemic circulation. Absorption of AL-294 increased when the particle size of the emulsion was smaller. The reason was assumed to be that the smaller particle size offered the greater oil-water interface for lipase activity against AL-294. 相似文献
8.
The flow of a liquid (or gas) with aerosol particles suspended in it in channels of different configurations is of great interest in the solution of many practical problems. The aim of the present paper is to develop a method for calculating the hydrodynamics and the heat and concentration transfer of aerosol particles for steady flow of an incompressible fluid in toroidal channels of circular section. The paper uses an implicit difference scheme with different approximations of the convective terms on a nonuniform grid (directed differences, central differences, and the monotonic approximation of Samarskii), which makes it possible to reduce the solution of the system of the original nonlinear partial differential equations to the successive solution of one-dimensional systems [1]. The method proposed by Polezhaev and Gryaznov [2] is used to calculate the boundary conditions for the vorticity. The hydrodynamic equations are solved by means of the difference scheme developed by Khristov [3], and the heat and concentration transfer equations are solved by the difference scheme proposed by Val'tsiferov and Polezhaev [4]. The obtained results make possible a detailed analysis of the dependence of the basic integrated (particle capture coefficient) and local characteristics on the values of the relevant dimensionless numbers, namely, the Dini, Prandtl, and Schmidt numbers, the parameter R/Rk, which characterizes the curvature of the channel, and the dimensionless parameter Wf = fRG(TO–TW)/(pM), which characterizes the rate of thermophoresis.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 159–164, March–April, 1984. 相似文献
9.
The results of a series of works on the synthesis and investigation of various carbon nanostructures and elaboration of functional
materials of their basis are generalized and reviewed. Fullerenes and single-, double-, and multi-walled carbon nanotubes
were prepared by the electric arc evaporation of graphite and metal—graphite rods. Diverse types of carbon nanofibers and
nanotubes were grown by the catalytic pyrolysis of ethylene and methane. Graphene structures were synthesized by the chemical
reduction of graphite oxide. Methods for isolation, purification, and functionalization of carbon nanostructures were elaborated.
Chemical transformations in the fullerene—metal phase—hydrogen system were studied. Methods for metal cluster application
on carbon nanostuctures and formation of metal hydride—carbon composites were developed. The possibilities were elucidated
of using carbon nanostructures for the development of hydrogen accumulating and hydrogen generating composites, for forming
carbon—polymer and carbon—ceramic composites, for preparing hardening additives to polymers and glue compositions, and for
producing high-performance catalysts for hydrogenation and redox processes in fuel cells. 相似文献
10.
We present a fitting method for obtaining a functional form of the refractive index profile of planar microlenses made by ion exchange techniques from total shearing interferometric measurements. Compared to the usual power series expansion fit, this method allows a reduction in the number of coefficients needed to characterize a lens. 相似文献