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41.
Previous results on quasi-classical limit of the KP hierarchy and itsW-infinity symmetries are extended to the Toda hierarchy. The Planck constant now emerges as the spacing unit of difference operators in the Lax formalism. Basic notions, such as dressing operators, Baker-Akhiezer functions, and tau function, are redefined.W
1 + symmetries of the Toda hierarchy are realized by suitable rescaling of the Date-Jimbo-Kashiara-Miwa vertex operators. These symmetries are contracted tow
1 + symmetries of the dispersionless hierarchy through their action on the tau function. 相似文献
42.
V.A. Kheraj C.J. Panchal P.K. Patel B.M. Arora T.K. Sharma 《Optics & Laser Technology》2007,39(7):1395-1399
The optical output power of a laser diode can be enhanced by anti-reflection (AR) and high-reflection (HR) facet coatings, respectively, at the front and back facet. AR and HR coatings also serve the purpose of protection and passivation of laser diode facets. In this work, we have designed and optimized a single layer λ/4 thick Al2O3 film for the AR coating and a stack of λ/4 thick Al2O3/λ/4 thick Si bi-layers for the HR coating for highly strained InGaAs quantum-well edge emitting broad area (BA) laser diodes. Effect of the front and back facet reflectivities on output power of the laser diodes has been studied. The light output versus injected current (L–I characteristics) measurements were carried out on selected devices before and after the facet coatings. We have also carried out the numerical simulation and analysis of L–I characteristics for this particular diode structure. The experimental results have been compared and verified with the numerical simulation. 相似文献
43.
Keisuke Yoshiki Hiroki Azuma Kazuhiko Yoshioka Mamoru Hashimoto Tsutomu Araki 《Optical Review》2005,12(5):415-419
We have investigated the fluorescence lifetime properties of 8 calcium ion probes, calcium-green-1, calcium green-2, calcium
green-5N, calcium orange, oregon green 488 BAPTA-6F, fluo-3, fluo-4, and fluo-5N. We found that the decay time of calcium
green-5N varied more sensitively with calcium concentration than calcium green-1 which was known to be a highly sensitive
probe. We have also found that the center of observable range of calcium concentration by fluorescence lifetime measurement
is lower than that by fluorescence intensity measurement. 相似文献
44.
Gerhard Brner 《Physik in unserer Zeit》2006,37(6):264-265
45.
基于Monte Carlo模拟算法, 建立了粒子输运模型, 通过对盒形窗内圆窗片表面次级电子倍增现象进行数值仿真, 获得了TE11模非均匀分布电场作用下次级电子倍增的规律. 结果表明: 在微波输入端, 指向窗片表面的磁场力起到了维持次级电子与窗片碰撞的作用, 在电场强度较高的区域倍增剧烈, 有质动力对倍增无贡献; 在微波输出端, 受背离窗片表面磁场力的影响, 在表面静电场较弱的情况下, 次级电子倍增不能发生; 当表面静电场足以维持单面倍增的发生, 随着传输功率的增大, 电子渡越时间增长, 有质动力使得倍增强烈的区域由强电场区逐渐转移到弱电场区域. 对利用外静电场抑制微波输入端次级电子倍增效应的方法进行了数值模拟验证.
关键词:
圆窗片
11模')" href="#">TE11模
次级电子倍增
MonteCarlo模拟 相似文献
46.
Zhipeng Hou Jinbao Zhang Shifeng Xu Chunji Wu Jingjing Zhang Zihan Wang Kunlong Yang Wenquan Wang Xiaobo Du Feng Su 《Journal of magnetism and magnetic materials》2012
The phases, microstructure, and magnetic properties of Co80Zr18−xNbxB2 (x=1, 2, 3, and 4) melt-spun ribbons were investigated. The small substitution of Nb for Zr in the Co–Zr–B melt-spun ribbons resulted in the improvement of magnetic properties, especially the coercivity. The main effect of added Nb on the coercovity of Co–Zr–Nb–B melt-spun ribbons, originated from modification of the grain size of Co11Zr2 phase. The coercivity of the Co–Zr–Nb–B melt-spun ribbons depends on the annealing temperature. The optimal magnetic properties of Hc=5.1 kOe, and (BH)max=3.4 MGOe were obtained in the Co80Zr15Nb3B2 melt-spun ribbons annealed at 600 °C for 3 min. 相似文献
47.
Investigation of structural and optical properties of ZnO films co-doped with fluorine and indium 总被引:1,自引:0,他引:1
Undoped ZnO film and ZnO films, which are co-doped with F and In (FIZO) at different concentrations, were synthesized by sol–gel technique and the effects of co-doping of F and In on structural and optical properties of ZnO thin films were investigated. The concentration ratio of [F]/[Zn] was altered from 0.25 to 1.75 with 0.50 step at.% mole and [In]/[Zn] was altered from 0.25 to 1.00 with 0.25 step at.% mole. X-ray diffraction analysis indicates that the films have polycrystalline nature and the (0 0 2) preferred orientation is the stronger peak. No extra phases involving zinc, fluorine and indium compounds were observed even at high F and In content. The grain size of undoped ZnO and FIZO thin films varied between 15 and 20 nm with a small fluctuation. From the SEM images, although the undoped ZnO had a smooth and particle-shaped surface, FIZO films had nanofiber-networks shapes over the surface with average size of 500 nm. The surface morphologies and crystallite sizes for the F and In doped films were slightly different from than those of undoped film. From the optical study, a slight shrinkage of band gap was backwardly observed from 3.36 to 3.25 eV with the increasing of F and In content. 相似文献
48.
Vijay Singh R.P.S. Chakradhar J.L. Rao Young-Dahl Jho 《Physica B: Condensed Matter》2012,407(12):2289-2294
The LaAl11O18:Mn2+ powder phosphor has been prepared using a self-propagating synthesis. Formation and homogeneity of the LaAl11O18:Mn2+ phosphor has been verified by X-ray diffraction and energy dispersive X-ray analysis respectively. The EPR spectra of Mn2+ ions exhibit resonance signals with effective g values at g≈4.8 and g≈1.978. The signal at g≈1.978 exhibits six-line hyperfine structure and is due to Mn2+ ions in an environment close to tetrahedral symmetry, whereas the resonance at g≈4.8 is attributed to the rhombic surroundings of the Mn2+ ions. It is observed that the number of spins participating in resonance for g≈1.978 increases with decreasing temperature obeying the Boltzmann law. Upon 451 nm excitation, the photoluminescence spectrum exhibits a green emission peak at 514 nm due to 4T1 (G)→6A1 (S) transition of Mn2+ ions. The crystal field parameter Dq and Racah inter-electronic repulsion parameters B and C have been evaluated from the excitation spectrum. 相似文献
49.
Beatrice Malgesini Eduard Felder Nicola Mongelli Gianluca Papeo 《Molecular diversity》2009,13(1):53-56
Polyfluorinated N-α-Fmoc--Boc-l-lysine represents the best-in-class among a set of polyfluorinated amino acids (PFAs) which are useful tools for 19F NMR-Based Screening. In this communication, optimized reaction conditions that allowed for the multi-gram preparation of
this unnatural amino acid are reported. 相似文献
50.