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991.
采用第一性原理在B3LYP\6-311G水平上对MnPm(n=1~2, m=1~10)(M=Be 、Mg 、Ca)团簇进行几何构型优化和频率分析,得到团簇各个尺寸的基态结构,结果表明,在m+n=5~6时锥体结构居多,相应的稳定性要高于同尺寸其他构型,m+n>6时,基态结构中出现四元环和五元环。裂化能和二阶能量差分计算结果表明,MPm(m=1~10)团簇在m=2时同时获得局域的最大值, Be2Pm(m=1~10)团簇幻数结构呈现规则的奇偶振荡。Be掺杂P团簇稳定性高于同尺寸的Mg 、Ca掺杂,与Mg 、Ca相比Be原子更易于与P原子结合。稳定结构团簇红外和拉曼光谱显示,高频段MP2团簇红外和拉曼活性较强,Mg2P2, Ca2P2团簇红外谱主峰在高频段出现,与拉曼活性谱主峰相反。 相似文献
992.
Using the finite-difference time-domain (FDTD) method, we simulate the coupling between a gold nanorod and gold nanoparticles
with different plasmonic resonant frequencies/volumes as well as that between the nanorod and a dielectric nanosphere. The
influences of coupling with different nanoparticles on the excitation of a forbidden longitudinal surface plasmon mode of
the nanorod under normal incidence are investigated. It is found that the cause of this excitation is the broken symmetry
of the local electric field experienced by the nanorod resulting from the charge pileup on the other nanoparticle. This result
is valuable for understanding the near-field optical characterization of plasmonic metal nanoparticles.
Supported by the National Natural Science Foundation of China (Grant Nos. 10821062 and 10804004), the National Basic Research
Program of China (Grant No. 2007CB307001), and the Specialized Research Fund for the Doctoral Program of Higher Education
(Grant No. 200800011023)
Contributed by GONG QiHuang 相似文献
993.
994.
Structure, ferroelectric and dielectric properties of Bi2WO6 with different bismuth content
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This paper reports that the Bi 2 WO 6 ferroelectric ceramics with excess Bi 2 O 3 of 0.0, 2.0, 3.5 and 5.0 wt.% of the stoichiometric composition are prepared by the conventional solid-state reaction method. Their microstructure, ferroelectric properties, the concentration and mobility of the defects have been analysed systematically. With increasing Bi content, the remnant polarization decreases, and the broken-down voltage increases. The optimum Bi excess, 3.5, lowers the oxygen vacancy concentration, while further Bi-addition brings about more defects. The activation energies fitted from cole-cole plots are 0.97 eV, 1.07 eV, 1.18 eV, and 1.33 eV, respectively. This suggests that the mobility of the defects is weakened by Bi-addition, which may be due to the increase of the ratio of the number of Bi 2 O 2 layers to that of the perovskite blocks. 相似文献
995.
TiC/PVDF nanocomposite is prepared via simple blending and hot pressing route. Percolation theory was employed to explain the dielectric behavior of the TiC/PVDF composites. The dependence of the dielectric properties of the composite on both volume fraction of the filler and frequency is investigated. High dielectric constant (? = 540) and low loss (tan δ = 0.48) of the composites at 100 Hz have been observed near the percolation threshold (0.12). The composites show a weak frequency dependence towards the high frequency range (10–100 kHz), regardless of the TiC content. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
996.
Protuberance cutting and recoverable damage of olfactory ensheathing cells (OECs) using femto-second laser surgery are reported. The damages of OECs protuberance are induced by using femtosecond laser surgery with different laser powers and scanning velocities. Through optimizing the parameters, steady cutting of OEC protuberance is achieved. After femtosecond laser surgery with 150 μ W and 10 μm/s is conducted, we found that the cell recovers its viability, such as growth, spread, and motility 1.5 h after the damage, which prove cell’s recovery and regeneration. Current work offers a novel method for establishing cell damage model and studying on cytokinetics. 相似文献
997.
A diode-pumped Nd:YAG oscillator laser with an end-pumped zigzag slab architecture and weak pump absorption is developed. An output power of 253 W with a slope efficiency of 50.2% and an optical-optical conversion efficiency of 39.6% is achieved from the resonator, which emits the maximum power of 290 W with 840-W pump power. An optimum laser diode (LD) array coolant temperature is chosen in an attempt to realize the weak but uniform pump absorption. of zigzag slab resonator depends sensitively on the Furthermore, we have confirmed that the performance incident angle of the beam at the slab end face. 相似文献
998.
Y.X. Gong L. Zhen J.T. Jiang C.Y. Xu W.Z. Shao 《Journal of magnetism and magnetic materials》2009,321(22):3702-3705
CoFe alloy nanoparticles with different particle sizes were successfully prepared by hydrogen-thermal reduction of CoFe2O4 microspheres at different temperatures. It was found that the real part of the permeability of the CoFe alloy nanoparticles increased with the decrease of the particle size, and accordingly the reflection loss (RL) peak moved towards the low-frequency region. The maximum RL of the coating based on CoFe alloy nanoparticles exceeded −23 dB, and a wide effective absorption band width (RL≤−10 dB) of about 6 GHz was simultaneously achieved. The EMA performance was confirmed to be tunable by the control of the absorber's particle size, and thus a new clue for the design of the EMA applications was supplied. 相似文献
999.
Haixuan Huang Jing Yang Xiangdong Gong Lili Wan Kai Wang Yeyong Zheng Xuan Han 《Optics Communications》2009,282(21):4198-4202
Based on the Left Perfect Shuffle (LPS) optical communication network constructed by cascade multi-stage LPS interconnection, using Looping algorithm, any arbitrary sequence of the input signals can be realized. However, instead of obtaining the simultaneous state codes of the same level node switches through mathematical analytical expressions directly, only routing tags of each channel can be obtained through mathematical analytical expressions so as to draw out topological chart of the network to obtain the state codes implied in the chart. Thus, the states of the switches cannot be directly programmed and controlled by computer in practical application. In this paper, based on the Looping algorithm, a method of stage code matrixes is presented to resolve this problem. By using the method, the simultaneous state codes of the same level’s four node switches can be directly obtained, which is convenient for the computer to provide controlled signals needed to finish the permutation for each node switch. The method of stage code matrixes provides further theoretical basis for the realization of optical switching by integration of Perfect Shuffle and high-speed optical switches. 相似文献
1000.