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991.
Gun Sang Jeon Chia-Chen Chang Jainendra K. Jain 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(3):271-282
We review and extend the composite fermion theory for semiconductor quantum dots in high magnetic fields. The mean-field model
of composite fermions is unsatisfactory for the qualitative physics at high angular momenta.
Extensive numerical calculations demonstrate that the microscopic CF theory,
which incorporates interactions between composite fermions, provides an excellent qualitative and quantitative account
of the quantum dot ground state down to the largest angular momenta studied,
and allows systematic improvements by inclusion of mixing between composite
fermion Landau levels (called Λ levels). 相似文献
992.
测量了氢气离子转动分辨的真空紫外脉冲场电离光电子谱.涵盖了15.30?18.09 eV能量范围内的H2+(X2§+g , v+=0?18,N+=0?5)?H2(X1§+g , v00=0, J00=0?4)的电离跃迁. 通过基于Buckingham-Orr-Sichel(BOS)模型的光谱拟合和对氢气离子振动带H2+(X2§+g ,v+=0?18)的转动光谱的分析, 发现实验上只观察到对应于¢N=N+-J00=0,§2的转动跃迁. 振动量子数v+ 越高,¢N=0的转动跃迁越占主导地位, 而转动谱线强度受邻 相似文献
993.
W.Y. Zhang C.H. Chiu L.C. Zhang K. Biswas H. Ehrenberg W.C. Chang J. Eckert 《Journal of magnetism and magnetic materials》2007
The effect of refractory element addition on phase transformation, crystallization behavior and magnetic properties of Pr8.5Fe81.5B10 (addition-free) and Pr8.5Fe81.5M2B10 (M=V, Cr, Nb, Zr, Ti) ribbons has been investigated. The annealed addition-free ribbon as well as the samples with V or Cr additions are mainly composed of the metastable Pr2Fe23B3 phase, whereas annealed ribbons with Nb, Zr or Ti additions primarily consist of Pr2Fe14B and a minor amount of Fe3B/boride. The complete suppression of the metastable Pr2Fe23B3 phase due to Nb, Zr or Ti additions leads to a significant enhancement of the magnetic properties. For example, the remanence, the coercivity and the energy product are remarkably increased from 2.5 kG, 0.4 kOe and 0.2 MG Oe for the addition-free material to 9.2 kG, 4.7 kOe and 7.6 MG Oe for the specimens with Nb addition. The successful elimination of the metastable Pr2Fe23B3 phase is believed to profit from two factors: (a) Nb, Zr or Ti atoms substitute the Pr site, comparatively increase the Pr content, and thus inhibit the nucleation of Pr-lean Pr2Fe23B3 phases, and (b) the formation of Nb, Zr, or Ti borides consumes some part of B, which hinders the generation of the B-rich Pr2Fe23B3 phase. 相似文献
994.
Composite coating of Ni-Co/Al2O3 was deposited in Ce2(SO4)3 containing electrolyte by pulse reverse current (PRC) method. The effect of Ce2(SO4)3 in electrolyte on morphology, microstructure, composition, micro-hardness and residual macrostress of composite coating was investigated. The results indicates that with addition of Ce2(SO4)3 in electrolyte, the composite coating becomes uniform, compact and possesses finer grains, the composite content of Al2O3 is enhanced, the micro-hardness of composite coating is improved, while the residual macrostress is decreased. 相似文献
995.
996.
CdS/TiO2/漂珠复合光催化剂制备及其降解高效氯氰菊酯研究 总被引:2,自引:0,他引:2
采用溶胶-凝胶-浸渍法制备了Cds/TiO2/漂珠复合光催化剂,通过SEM,XRD对其结构进行了表征.以高效氯氰菊酯(BEC)杀虫剂的光催化降解为模型反应,研究了CdS/TiO2/漂珠的光催化性能,探讨了影响催化剂活性的因素及采用太阳光作光源处理BEC的可行性.结果表明,CdS/TiO2/漂珠投加量为3 000mg·L-1,初始浓度为45 mg·L-1、初始pH为6.5,通气量为200 mL·min-1时间为60 min,BEC降解率分别为92.1%(125W高压汞灯)和79.3%(5 W紫外灯),采用太阳光照射300 min,BEC降解率可达93.4%.BEC的降解反应遵从L-H动力学模型,测得反应速率常数9.80 mg·(L·min)-1,吸附常数4.36×10-3 L·mg-1. 相似文献
997.
Surface status and size influences of nickel nanoparticles on sulfur compound adsorption 总被引:1,自引:0,他引:1
Metallic nickel nanoparticles were incorporated on mesoporous silica to remove sulfur compounds in diesel selectively. In the first method, nickel nanoparticles were formed on mesoporous silica SBA-15 by impregnation and subsequent reduction of nickel nitrate. The sulfur adsorption capacity was strongly dependent on the nickel loading and the average nickel particle size. In the second method, nickel nanoparticles were synthesized in solution in the presence of a capping agent and then incorporated in mesoporous silica MCF by sonication. Although these particles maintain their sizes on the MCF surface after heat treatment, capping agent remaining on the Ni particle surface might interfere the adsorption of sulfur compounds. 相似文献
998.
In this report, we demonstrate the efficient generation of collinearly propagating photon pairs in a bulk periodically poled potassium titanyl phosphate pumped by a cw laser. The detected coincidence counts are more than 7400/s with 3.58 mW pump power in a Hanbury-Brown-Twiss-type experiment. The estimated photon pair production rate is about 0.73 MHz/mW. This is very promising for some applications, such as quantum key distribution, proof of the Bell-inequality, preparation of single photon states in broadband wave packets, Franson-type interference and so on. 相似文献
999.
Al-doped ZnO (AZO) transparent conductive thin films were grown by magnetron sputtering with AZO (98 wt.% ZnO, 2 wt.% Al2O3) ceramic target in Ar + H2 ambient at a relatively low temperature of 100 °C. To investigate the dependence of crystalline and properties of as-grown AZO films on the H2-flux, X-ray diffraction (XRD), X-ray photoemission spectrometer (XPS), Hall and transmittance spectra measurements were employed to analyze the AZO samples deposited with different H2-flux. The results indicate that H2-flux has a considerable influence on the transparent conductive properties of AZO films. The resistivity of 4.15 × 10−4 Ω cm and the average transmittance of more than 94% in the visible range were obtained with the optimal H2-flux of 1.0 sccm. Such a low temperature growing method present here may be especially useful for some low-melting point photoelectric devices and substrates. 相似文献
1000.
An All-Solid-State Tunable Dual-Wavelength Ti:Sapphire Laser with Quasi-Continuous-Wave Outputs 下载免费PDF全文
A high power dual-wavelength Ti:sapphire laser system with wide turning range and high efficiency is described, which consists of two prism-dispersed resonators pumped by an a11-solid-state frequency-doubled Nd:YAG laser. Tunable dual-wavelength outputs, with one wavelength range from 750nm to 795nm and the other from 80Ohm to 850nm, have been demonstrated. With a pump power of 23 W at 532nm, a repetition rate of 6.5kHz and a pulse width of 67.6ns, the maximum dual-wavelength output power of 5.6 W at 785.3nm and 812.1 run, with a pulse width of 17.2ns and a line width of 2nm, has been achieved, leading to an optical-to-optical conversion efficiency of 24.4%. 相似文献