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91.
Medine Gavin M. Klabunde Kenneth J. Zaikovskii Vladimir 《Journal of nanoparticle research》2002,4(4):357-366
The thermodynamically favored reaction of solid strontium oxide with gaseous hydrogen sulfide is kinetically enhanced to a large degree by the use of higher surface area nanocrystalline SrO in the form of brush-like collections of metal oxide fibers. An unusual feature is that the reaction SrO + H2S SrS + H2O proceeds stoichiometrically at room temperature, but at higher temperatures the reaction efficiency goes down, apparently due to rapid temperature induced crystal growth of the nanocrystalline SrO. The samples studied vary in crystallite size from 20 to 27nm, while average particle size (nanocrystal aggregates) varies in the following order; aerogel prepared SrO (100nm) 相似文献
92.
ZHANG Qiang ZHOU Jifu & LI Jiachun Institute of Mechanics Chinese Academy of Sciences Beijing 《中国科学G辑(英文版)》2005,48(4):469-484
As one of the important coherent structures in the near-wall region, turbulent burst is responsible for the production and transport of major turbulent kinetic energy and Rey- nolds stress[1]. Nearly half of turbulent kinetic energy or Reynolds stress is produced in the near-wall region, and 80% flows in outer region only contribute 20% of them. Both ejection and sweeping events contribute 60―70% of the turbulent shear stress respec- tively[2]. Recently, turbulent burst process has been foun… 相似文献
93.
The aim of our study is the development of a method for calculating the interface of dimerization of protein-protein complexes based on simplified medium-resolution structures. In particular, we wished to evaluate if the existing concepts for the computation of the Solvent-Accessible Surface Area (SASA) of macromolecules could be applied to medium-resolution models. Therefore, we selected a set of 140 protein chains and computed their reduced representations by topological analysis of their electron density maps at 2.85 A crystallographic resolution. This procedure leads to a limited number of critical points (CPs) that can be identified and associated to backbone and side-chain parts. To evaluate the SASA and interfaces of dimerization of the reduced representations, we chose and modified two existing programs that calculate the SASA of atomic representations, and tested (1) several radii tables of amino acids, (2) the influence of the backbone and side-chain points, and (3) the radius of the solvent molecule, which rolls over the surface. The results are shown in terms of relative error compared to the values calculated on the corresponding atomic representations of the proteins. 相似文献
94.
José A. Gá lvez Antonio Martí nez 《Proceedings of the American Mathematical Society》2000,128(12):3655-3660
We give optimal bounds of the height, curvature, area and volume of -surfaces in bounding a planar curve. The spherical caps are characterized as the unique -surfaces achieving these bounds.
95.
Matthieu Fradelizi 《Proceedings of the American Mathematical Society》2000,128(9):2735-2744
We define the sectional bodies associated to a convex body in and two related measures of symmetry. These definitions extend those of Grünbaum (1963). As Grünbaum conjectured, we prove that the simplices are the most dissymmetrical convex bodies with respect to these measures. In the case when the convex body has a sufficiently smooth boundary, we investigate some limit behaviours of the volume of the sectional bodies.
96.
激光金属汽化汽离混合区状态参量的稳定性及其影响因素分析 总被引:1,自引:0,他引:1
在汽离混合区激光强度时空修正的基础上,近似求解了流体力学模型下的状态参数,找出了稳定状态参数的共同自洽参量,分析了自洽参量的取值方法,研究了相关参数对自洽参量的影响机制,结果发现:(1)汽离混合区内,状态参量的稳定性可用自洽参量的稳定性来表征;(2)当入射激光强度小于108W.cm-2时,自洽参量随入射激光强度变化相对较快,稳定性差;当激光强度大于108W.cm-2时,自洽参量随入射激光强度变化相对较慢,稳定性高;(3)汽离混合区各处的约化自洽参量随辐照激光的波长成变周期增加的变化,波长越长,约化自洽参量越大;(4)要使自洽参量稳定,纹波较小,宜采取短波激光辐照;(5)当蒸汽压强小于2.7×106Pa时,自洽参量随蒸汽压强成指数递减规律变化;当蒸汽压大于2.7×106Pa时,自洽参量与蒸汽压强之间没有对应关系. 相似文献
97.
Sub Hur Hodeok Jang Yonghoon Kim Hanlim Lee Seongtaek Hwang Yunje Oh Y. J. Sung Y. S. Kim Jichai Jeong 《Optical and Quantum Electronics》2007,39(7):561-569
We investigate the performance limits of a pico-cell system using the radio- over-fiber technique with an electroabsorption
modulator (EAM) in a 2.4 GHz wireless local area network (WLAN) environment. To understand the performance limits of the system
using an EAM as the optical transceiver, we vary the optical modulation index (OMI) of the transmitter for different bias
voltages to the EAM. Power margins in the links are found to estimate a possible service range, and packet loss rates (PLRs)
in the pico-cell system are measured to evaluate the transmission performance. The total service range can be extended up
to 3 m by adjusting the OMI of the transmitter for different applied bias voltages to the EAM. 相似文献
98.
99.
S. M. Abdur Razzak Yoshinori Namihira Kazuya Miyagi Feroza Begum Shubi Kaijage Nguyen Hoang Hai Tatsuya Kinjo Nianyu Zou 《Optical Review》2007,14(1):14-16
This paper presents a novel technique for the control of chromatic dispersion and confinement loss in hexagonal photonic crystal
fibers (H-PCFs). It is demonstrated that it is possible to obtain very low chromatic dispersion of 0 ± 0:38 ps/(nm·km) in
the wavelength range of 1.41 to 1.66 μm and confinement loss of less than 0.0001 dB/km from a six ring modified H-PCF (MH-PCF).
The higher order dispersion at 1.55 μm is about −0.001 ps/(nm2-km). 相似文献
100.
Using results for the distribution of perimeters of random polygons arising from random lines in a plane, we obtain new analytic
approximations to the distributions of areas and local line densities for random polygons and compute various limiting properties
of random polygons. Using simulation, we show that the lengths of adjacent sides of polygons generated by random line processes
in the plane are correlated with ρ=0.616±0.001. 相似文献