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151.
MoS2 nanotube coated SWNT (Single wall carbon nanotube) bundles have been successfully prepared by adsorbing (NH4)2MoS4 onto SWNT bundles and subsequent heat treatment under H2 at 900 ℃ in a tube furnace. The morphologies, structure and composition of the as-prepared sample were investigated by XRD, SEM, HRTEM coupled with EDS. The formation mechanism has also been preliminarily discussed. 相似文献
152.
The conformational properties and elastic behaviors of protein-like single chains in the process of tensile elongation were investigated by means of Monte Carlo method. The sequences of protein-like single chains contain two types of residues: hydrophobic (H) and hydrophilic (P). The average conformations and thermodynamics statistical properties of protein-like single chains with various elongation ratio λ were calculated. It was found that the mean-square end-to-end distance r increases with elongation ratio,λ. The tensor eigenvalues ratio of : decreases with elongation ratio λ for short (HP)x protein-like polymers, however, the ratio of : increases with elongation ratioλ,especially for long (H)x sequence. Average energy per bond increases with elongation ratioλ, especially for(H)x protein-like single chains. Helmholtz free energy per bond also increases with elongation ratioλ. Elastic force (f), energy contribution to force (fU) and entropy contribution to force (fs) for different protein-like single chains were also calculated.These investigations may provide some insights into elastic behaviors of proteins. 相似文献
153.
On the Crystal Structures of CH3PF2H+AsF6? and CH3PF2H+SbF6? and a simple Method for Preparation of CH3PF2 A simple method for preparation of CH3PF2 from CH3PCl2 is reported. The phosphonium salts CH3PF2H+MF6? are obtained by the reaction of CH3PCl2 with superacidic systems HF/MF5 (M = As, Sb). CH3PF2H+SbF6? crystallizes in the space group P1 with a = 548.4(4) pm, b = 695.5(8) pm, c = 960.2(9) pm, α = 94.68(5)°, β = 97.19(6)°, γ = 94.41(6)° and Z = 2. CH3PF2H+SbF6? crystallizes in P1 with a = 554.3(3), b = 724.2(4), c = 970.4(5), α = 94.73(4)°, β = 96.14(5)°, γ = 95.30(4)°. 相似文献
154.
氢分子在金属表面的解离吸附与氢原子在金属体相的扩散是个典型的表面过程.前者在甲烷化及合成氨等基础化工反应中起着关键作用;后者常常导致金属材料的脆化与断裂,但过渡金属及其合金是安全和优良的储氢材料.因此,研究氢分子在金属表面的解离吸附与氢原子在金属体相的扩散,是多相催化与金属物理广泛感兴趣的课题,具有重要的理论和应用价值.本文采用分子动力学方法初步探讨了二者之间的关联.分子催化动力学为从微观层次上研究上述课题提供了一种理论方法.本文采用经过我们改进的半经验LEPS方法,计算了氢分子在Pd(100)和(110)晶面的解离和氢原子在钯表面与体相扩散的相互作用位能面,并根据计算结果探讨了其微观机理. 相似文献
155.
ZHENG Hong WANG Shaoqing & CHENG Huiming Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang China 《中国科学B辑(英文版)》2004,47(3):222-227
Hydrogen is a kind of clean, sustainable and renewable energy carrier. Of the problems to be solved for the utilization of hydrogen energy, how to store and transport hydrogen has been given high priority on the research agenda. Recently, carbon nanotubes (CNTs) were reported to be very promising candidates for hydrogen uptake[1], which may have possibility to satisfy the benchmark set by the US Department of Energy (DOE) Hydrogen Plan for fuel cell powered vehicles: a gravimetric density … 相似文献
156.
M. Yamanaka Y. Takeda S. Tanigawa A. Nishizawa N. Noda J. Fujita M. Takai M. Shimobayashi Y. Hayashi T. Koizumi K. Nagasaka S. Okajima Y. Tsunawaki A. Nagashima 《International Journal of Infrared and Millimeter Waves》1980,1(1):57-76
A twin optically-pumped far-infrared CH3OH laser has been constructed for use in plasma diagnostics. The antisymmetric doublet due to the Raman-type resonant two-photon transition is reproducibly observed at 118.8 m. With the 118.8-m line, it is obtained from the frequency separation of the anti-symmetric doublet that CH3OH absorption line center is 16±1 MHz higher than the pump 9.7-m P(36) CO2 laser line center. It is shown that the Raman-type resonant two-photon transition is useful in order to get several-MHz phase modulation for the far-infrared laser interferometer. Some preliminary performances of this twin laser for the modulated interferometer are described.This work was carried out under the collaborating research program at the Institute of Plasma Physics, Nagoya University, Nagoya 464, Japan. 相似文献
157.
D. K. Mansfield L. C. Johnson A. Mendelsohn 《International Journal of Infrared and Millimeter Waves》1980,1(4):631-640
A modulated far-infrared laser interferometer which is presently operating on the PDX experiment at Princeton is described. The interferometer geometry permits the characterization of inside D, outside D as well as circular discharges. To achieve this versatility, a titanium corner cube reflector, mounted inside the PDX vacuum vessel is used in conjunction with a second visible wavelength interferometer for vibration corrections. In addition, the use of room temperature quasi-optical Schottky diodes in the far-infrared interferometer is reported. The minimum detectable line average density of the system is 5×1011 cm–3. 相似文献
158.
A. N. Chekhlov 《Journal of Structural Chemistry》2007,48(6):1160-1163
The second crystal modification (II) of 1,10-diazonia-18-crown-6 dichloride [H2DA18C6]2+·2Cl?, where [H2DA18C6]2+ is the 1,10-diaza-18-crown-6 dication (DA18C6) with two protonated nitrogen atoms, was investigated by XRD. The monoclinic modification (II) (space group P21/n, a = 9.600 Å, b = 5.689 Å, c = 15.749 Å, β = 91.03°, Z = 2) was solved by direct methods and refined by full-matrix least squares analysis in an anisotropic approximation to R = 0.032 for all 2494 independent reflections collected (CAD-4 automatic diffractometer, λMoK α). In modification II, the conformation of the DA18C6 dication and the ion packing differ from those in triclinic modification I investigated previously. 相似文献
159.
160.
T. Itagaki E. Rokuta H.‐S. Kuo K. Nomura T. Ishikawa B.‐L. Cho I.‐S. Hwang T. T. Tsong C. Oshima 《Surface and interface analysis : SIA》2007,39(4):299-303
We observed field emission microscopy (FEM) patterns of noble‐metal (NM) covered W nano‐tips with three different apex structures fabricated by field evaporation. Each of the three tips was terminated with a single atom, three atoms or ten atoms. We investigated the temporal changes in the FEM of these tips to discuss the stabilities in the spatial distributions of the field emission (FE) beams. The single‐atom tip showed two characteristics that were superior to the others. First, the beams emitted from the single‐atom tip were the most collimated among the three tips (the semi‐cone angle of 1.0° , FWHM). Second, adsorption of residual gas had little influence on FE from the single‐atom tip, while the other tips were easily contaminated even at ultra high vacuum, resulting in the emission fluctuation. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献