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851.
Tan Sandra S. Y. Varvitsiotis Antonios Tan Vincent Y. F. 《Journal of Optimization Theory and Applications》2021,190(1):56-81
Journal of Optimization Theory and Applications - We introduce a new framework for unifying and systematizing the performance analysis of first-order black-box optimization algorithms for... 相似文献
852.
Xixi Wang Jiankai Shan Wei Liu Jing Li Hongwei Tan Xichen Li Guangju Chen 《Molecules (Basel, Switzerland)》2021,26(13)
In this work, we have investigated the binding conformations of the substrate in the active site of 5-HIU hydrolase kpHIUH and its catalytic hydrolysis mechanism. Docking calculations revealed that the substrate adopts a conformation in the active site with its molecular plane laying parallel to the binding interface of the protein dimer of kpHIUH, in which His7 and His92 are located adjacent to the hydrolysis site C6 and have hydrogen bond interactions with the lytic water. Based on this binding conformation, density functional theory calculations indicated that the optimal catalytic mechanism consists of two stages: (1) the lytic water molecule is deprotonated by His92 and carries out nucleophilic attack on C6=O of 5-HIU, resulting in an oxyanion intermediate; (2) by accepting a proton transferred from His92, C6–N5 bond is cleaved to completes the catalytic cycle. The roles of His7, His92, Ser108 and Arg49 in the catalytic reaction were revealed and discussed in detail. 相似文献
853.
Light incident onto an anisotropic crystal is divided into the ordinary and the extraordinary waves which vibrate in two perpendicular directions. Because of the tensor property of the dielectric constant, the direction of the electric displacement is not parallel to the vector of the incident electric field. An optical torque is induced by incidence of the linearly polarized light and propagating through the crystal. The optical torque tends to rotate the directions of eigenvibration which results in self-modulation of the ordinary and the extraordinary waves, and causes an energy splitting of the left (l)-, and the right (r)-handed circularly polarized waves in the crystal. The l- and the r-photons are correlated through the optical torque, which are found to be in an entanglement state. 相似文献
854.
ABSTRACT A new catalytic kinetic fluorescent quenching method for the determination of trace gold(III) was investigated. The method was based on the catalytic effect of gold on oxidation of 3-(3′-methylphenyl)-5- (2′-arsenoxylphenylazo) rhodanine by hydrogen peroxide in potassium hydrogen phthalate–hydrochloric acid (pH = 3.4). Under the optimum conditions, the great decrease of fluorescence intensity has a linear relationship against the concentration of gold in the range of 0 to 12.0 µg·L?1 with a detection limit of 6.0 × 10?10g·L?1. The coexistent metal ions can be separated, and gold can be enriched by TBP resin of solid-phase extraction, which greatly improves the selectivity and sensitivity of the system. The method can be used to determine trace amounts of gold in ore samples successfully with satisfactory results. 相似文献
855.
BaWO4-II has been synthesized at 5 GPa and 610°C. Its high pressure behavior was studied by in situ synchrotron X-ray diffraction measurements at room temperature up to 17 GPa. BaWO4-II retains its monoclinic structure. Bulk and axial moduli determined by fitting a third-order Birch–Murnaghan equation of state to lattice parameters are: K 0=86.2±1.9 GPa, K 0(a)=56.0±0.9 GPa, K 0(b)=85.3±2.4 GPa, and K 0(c)=146.1±3.2 GPa with a fixed K′=4. Analysis of axial compressible modulus shows that the a-axis is 2.61 times more compressible than the c-axis and 1.71 times more compressible than the b-axis. The beta angle decreases smoothly between room pressure and 17 GPa from 93.78° to 90.90°. 相似文献
856.
在火炮上利用金属铋(Bi)直接撞击单晶LiF窗口, 开展了金属Bi反向碰撞的冲击加载-卸载实验研究, 实验采用激光位移干涉测试系统, 获得了金属Bi在11—16 GPa压力范围内完整的卸载粒子速度剖面. 实验结果结合特征线方法计算表明, 金属Bi经冲击加载进入体心立方相, 并在11—16 GPa冲击压力作用下发生了卸载熔化, 界面粒子速度剖面的卸载拐点, 对应着金属Bi经冲击加载后发生的卸载熔化, 而这一结论同Cox的理论计算及一维流体力学程序计算结果基本一致. 本文报道的金属Bi卸载波剖面解读技术, 对于认识冲击加载下其他相似材料相变具有实用价值. 相似文献
857.
858.
Dongfang Jia Bin Tan Zhaoying Wang Chunfeng Ge Tianxin Yang Wenjun Ni Shichen Li 《中国光学快报(英文版)》2006,4(6)
By using the amplified 10-GHz, 5.5-ps sech2 pulses with high quality and chirp-free from regeneratively mode-locked fiber laser (RMLFL) as the soliton source, 2-5 order optical soliton phenomena are observed successfully in a 4.28-km dispersion flattened fiber. The experimental results agree well with the theoretical calculation. 相似文献
859.
X.Y. Dou Z.P. Zhou P.H. Tan L. Song L.F. Liu X.W. Zhao S.D. Luo X.Q. Yan D.F. Liu J.X. Wang Y. Gao Z.X. Zhang H.J. Yuan W.Y. Zhou S.S. Xie 《Physica E: Low-dimensional Systems and Nanostructures》2005,27(4):469-473
In this paper, we developed a new kind of substrate, the silver-coated anodic aluminum oxide (AAO), to investigate the characters of surface-enhanced resonant Raman scattering (SERRS) of the dilute single-walled carbon nanotubes. Homogeneous Ag-coated AAO substrate was obtained by decomposing the AgNO3 on the surface of AAO. single-walled carbon nanotubes (SWNTs) were directly grown onto this substrate through floating catalyst chemical vapor deposition method (CVD). SERRS of SWNTs was carried out using several different wavelength lasers. The bands coming from metallic SWNTs were significantly enhanced. The two SERRS mechanisms, the “electromagnetic” and “chemical” mechanism, were mainly responsible for the experiment results. 相似文献
860.
X. Liu Y. Xia F. Li Z. Tan B. Huang M. Zhao L. Ye X. Xu 《Applied Physics A: Materials Science & Processing》2005,81(3):635-638
Implanted-fluorine profiles in ITO films have been accurately measured using the 19F(p,αγ)16O resonance nuclear reaction at ER=872.1 keV, with width Γ=4.2 keV. A proper deconvolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The experimental range distribution parameters, Rp and ΔRp, were compared with those obtained from Monte Carlo simulation codes. PACS 61.72.Ww; 68.55.Ln 相似文献