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991.
992.
波导层结构设计是制备太赫兹(THz)量子级联激光器的关键问题之一.本文基于德鲁得(Drude)模型,利用时域有限差分(FDTD)法,对Si/SiGe量子级联激光器的波导层进行优化设计,从理论上对传统的递变折射率波导、单面金属波导、双面金属波导以及金属/金属硅化物波导横磁模(TM模)的模式损耗和光场限制因子进行了对比分析.结果表明,金属/金属硅化物波导不但可以减小波导损耗,而且有很高的光学限制因子,同时其工艺也比双面金属波导容易实现,为Si/SiGe太赫兹量子级联激光器波导层的设计提供了一定的理论指导. 相似文献
993.
994.
通过建立主、从式宇宙空间结构改善了量子算法的运行效率,非正交二次B样条小波和最小二乘小波支持向量回归机对零件边缘进行检测,给出了微小零件尺寸检测流程。试验仿真显示该算法对微小零件尺寸测量数据波动范围较小,方差值相比其他方法值较低,其中UQ算法测量的外轮直径测量方差值比HI、MM、AIT、IF、IGR算法分别减少了75.29%,78.40%,64.47%,60.95%,52.15%;UQ算法测量的内轮直径测量方差值比HI、MM、AIT、IF、IGR算法分别减少了72.89%,76.75%,62.66%,59.22%,50.13%,提高了微小零件的精度测量。 相似文献
995.
Mao Rongwei Zuo Yuhu Li Chuanbo Cheng Buwen Teng Xuegong Luo Liping Zhang Heshun Yu Jinzhong and Wang Qiming 《半导体学报》2005,26(2):271-275
A novel bonding method using silicate gel as bonding medium is developed.High reflective SiO2/Si mirrors deposited on silicon substrates by e-beam deposition are bonded to the active layers at a low temperature of 350℃ without any special treatment on bonding surfaces.The reflectivities of the mirrors can be as high as 99.9%.A Si.based narrow band response InGaAs photodetector is successfully fabricated,with a quantum efficiency of 22.6% at the peak wavelength of 1.54μm,and a full width at half maximum of about 27nm.This method has a great potential for industry processes. 相似文献
996.
Yang Hui Chen Lianghui Zhang Shuming Chong Ming Zhu Jianjun Zhao Degang Ye Xiaojun Li Deyao Liu Zongshun Duan Lihong .. 《半导体学报》2005,26(2):414-417
Studies on first GaN-based blue-violet laser diodes(LDs) in China mainland are reported.High quality GaN materials as well as GaN-based quantum wells laser structures are grown by metal-organic chemical vapor deposition method.The X-ray double-crystal diffraction rocking curve measurements show the fullwidth half maximum of 180″ and 185″ for (0002) symmetric reflection and (10-12) skew reflection,respectively.A room temperature mobility of 850cm2/(V·s) is obtained for a 3μm thick GaN film.Gain guided and ridge geometry waveguide laser diodes are fabricated with cleaved facet mirrors at room temperature under pulse current injection.The lasing wavelength is 405.9nm.A threshold current density of 5kA/cm2 and an output light power over 100mW are obtained for ridge geometry waveguide laser diodes. 相似文献
997.
998.
Despite the importance of quantum dots in a wide range of biological, chemical, and physical processes, the structure of the molecular layers surrounding their surface in solution remains unknown. Thus, knowledge about the interaction mechanism of Nitrogen enriched Carbonaceous Quantum Dots’ (N-CQDs) surface with water—their natural environment—is highly desirable. A diffusive and Stern layer over the N-CQDs, characterized in situ, reveals the presence of anionic water clusters [OH(H2O)n]−. Their existence explains new observations: (i) the unexpectedly low adsorption enthalpy (ΔHads) in a pressure range below 0.1 p/ps, and ΔHads being as high as 190 kJ/mol at 0.11 p/ps; (ii) the presence of a “conductive window” isolating nature—at p/ps below 0.45—connected to the formation of smaller clusters and increasing conductivity above 0.45 p/ps, (iii) Stern layer stability; and (iv) superhydrophilic properties of the tested material. These observables are the consequences of H2O dissociative adsorption on N-containing basic centers. The additional direct application of surfaces formed by N-CQDs spraying is the possibility of creating antistatic, antifogging, bio-friendly coatings. 相似文献
999.
张宗飞 《计算机工程与应用》2008,44(36):119-121
QoS组播路由问题是一个非线性的组合优化问题,已证明了该问题是NP完全问题。提出一种将基于量子计算原理的量子进化算法用于此类问题求解的算法,该算法对基本的量子进化算法进行改进,采用进化方程对量子门进行调整,采用量子变异阻止未成熟收敛,使之更适合于QoS组播路由的求解。仿真结果显示,该算法能快速搜索并收敛到全局(近似)最优解,且随着网络规模的增大算法保持了良好的特性,在寻优速度上与解的质量上优于其他进化算法与基本的量子进化算法。 相似文献
1000.
Alexander D. Volodin Alexander F. Smolyakov Alexander A. Korlyukov 《International journal of molecular sciences》2022,23(16)
The structure, thermodynamic parameters, and the character of thermal motion in octamethylcyclotetrasiloxane (D4) were investigated using the combination of experimental (single-crystal X-ray diffraction, thermochemistry) and theoretical (density functional theory calculations, ab initio molecular dynamics and metadynamics) methods. Single crystals of D4 were grown in a glass capillary in situ and the structures of high- (238–270 K) and low-temperature (100–230 K) phases were studied in detail. In the temperature interval 230–238 K, a phase transition with rather low enthalpy (−1.04(7) kcal/mol) was detected. It was found that phase transition is accompanied by change of conformation of cyclosiloxane moiety from boat-saddle (cradle) to chair. According to PBE0/6-311G(d,p) calculation of isolated D4, such conformation changes are characterized by a low barrier (0.07 kcal/mol). The character of molecular thermal motion and the path of phase transition were established with combination of periodic DFT calculations, including molecular dynamics and metadynamics. The effect of crystal field led to an increase in the calculated phase transition barrier (4.27 kcal/mol from low- to high-temperature phase and 3.20 kcal/mol in opposite direction). 相似文献