黎曼位形空间中约束多体系统的动力学分析

在黎曼位形空间中研究了约束多体系统的动力学问题．通过对约束矩阵的奇异值分解和修正的Ｇｒａｍ Ｓｃｈｍｉｄｔ过程构造了系统流形的法向和切向子空间的正交归一化基，将系统的动力学方程沿这双基进行投影，得到了求系统动力学响应的新型公式，给出了其数值分析的一种方法，并举了算例．     

Preparation and cryogenic mechanical properties of epoxy resins modified by poly(ethersulfone)

A thermoplastic, poly(ethersulfone) (PES) was used to modify a bisphenol‐F based epoxy resin cured with an aromatic diamine. The initial mixtures before curing, prepared by melt mixing, were homogeneous. Scanning electron microscopy (SEM) micrographs of solvent‐etched fracture surfaces of the cured blends indicated that phase separation occurred after curing. The cryogenic mechanical behaviors of the epoxy resins were studied in terms of tensile properties and Charpy impact strength at cryogenic temperature (77 K) and compared to their corresponding behaviors at room temperature (RT). The addition of PES generally improved the tensile strength, elongation at break, and impact strength at both RT and 77 K except the RT tensile strength at 25 phr PES content. It was interesting to observe that and the maximum values of the tensile strength, elongation at break, and impact strength occurred at 20 phr PES content where a co‐continuous phase formed. Young's modulus decreased slightly with the increase of the PES content. Moreover, the tensile strength and Young's modulus at 77 K were higher than those at RT at the same composition, whereas the elongation at break and impact strength showed the opposite results. Finally, the differential scanning calorimetry analysis showed that the glass transition temperature (T_g) was enhanced by the addition of PES. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 612–624, 2008     

ON TFE THIRD CONJECTURE OF K.OGIUE

In this paper, the authors prove following result:Let M~n be a complete Bechner-Kaehler submanifold of complex dimension (n≥4) in a complex projective space CP~(n p)(1) of complex dimension n p, endowed with the FubiniStudy metric of constant holomorphic sectional curvature 1. If the sectional curvature K of M~n satisfies K<1, then codimension p of M~n is not less then n(n 1)/2.     

A class of stochastic evolutions that scale to the porous medium equation

A class of reversible Markov jump processes on a periodic lattice is described and a result about their scaling behavior stated: Under diffusion scaling, the empirical measure converges to a solution of the porous medium equation on thed-dimensional torus. The process can be viewed as a randomly interacting configuration of sticks that evolves through exchanges of stick pieces between nearest neighbors through a zero-range pressure mechanism, with conservation of total stick length.     

Synthetic Study of 4‐Substituted Piperidine Ring in Elarofiban,RWJ‐50042, Tirofiban and Paroxetine

A new strategy for synthesizing a 4‐substituted piperidine ring uses the formal [3+3] cycloaddition reaction as the key protocol. This method provides a convenient formal synthesis of elarofiban, RWJ‐50042, tirofiban and paroxetine.     

Determination of pore diameter from rejection measurements with a mixture of oligosaccharides

This paper present a method to determine pore diameters and effective transport through membranes using a mixture of oligosaccharides. The results are compared with the Maxwell–Stefan equations. The partition coefficients of the solutes are a function of the pore diameter according to the Ferry equation. Thus, with the pore diameter as the only unknown parameter, rejection is described and the pore diameter is obtained by a Marquardt–Levenberg optimization procedure.     

关于RLC串联谐振曲线拐点分布规律的讨论

从理论上详细分析了RLC串联谐振曲线拐点分布规律，并指出了个别文献绘图中的不妥之处。     

1.3μm InGaAsP/InP双异质结发光管的特性研究

用液相外延技术生长的三层和四层InGaAsP/InP双异质结材料,制成了1.3μm InGaAsP/InP双异质结发光管。光功率输出(100mA)>1.0mW,最高2mW,尾纤输出功率(N.A.0.23,芯径60μ)>50μW。文中描述了器件的特性参数,还讨论了光功率的饱和特性和退化特性。     

Accelerated Multi-step Sulfur Redox Reactions in Lithium-Sulfur Batteries Enabled by Dual Defects in Metal-Organic Framework-based Catalysts

The sluggish sulfur redox kinetics and shuttle effect of lithium polysulfides (LiPSs) are recognized as the main obstacles to the practical applications of the lithium-sulfur (Li−S) batteries. Accelerated conversion by catalysis can mitigate these issues, leading to enhanced Li−S performance. However, a catalyst with single active site cannot simultaneously accelerate multiple LiPSs conversion. Herein, we developed a novel dual-defect (missing linker and missing cluster defects) metal–organic framework (MOF) as a new type of catalyst to achieve synergistic catalysis for the multi-step conversion reaction of LiPSs. Electrochemical tests and first-principle density functional theory (DFT) calculations revealed that different defects can realize targeted acceleration of stepwise reaction kinetics for LiPSs. Specifically, the missing linker defects can selectively accelerate the conversion of S₈→Li₂S₄, while the missing cluster defects can catalyze the reaction of Li₂S₄→Li₂S, so as to effectively inhibit the shuttle effect. Hence, the Li−S battery with an electrolyte to sulfur (E/S) ratio of 8.9 mL g⁻¹ delivers a capacity of 1087 mAh g⁻¹ at 0.2 C after 100 cycles. Even at high sulfur loading of 12.9 mg cm⁻² and E/S=3.9 mL g⁻¹, an areal capacity of 10.4 mAh cm⁻² for 45 cycles can still be obtained.     

Harnack Inequality and Applications for Infinite-Dimensional GEM Processes

The dimension-free Harnack inequality and uniform heat kernel upper/lower bounds are derived for a class of infinite-dimensional GEM processes, which was introduced in Feng and Wang (J. Appl. Probab. 44 938–949 2007) to simulate the two-parameter GEM distributions. In particular, the associated Dirichlet form satisfies the super log-Sobolev inequality which strengthens the log-Sobolev inequality derived in Feng and Wang (J. Appl. Probab. 44 938–949 2007). To prove the main results, explicit Harnack inequality and super Poincaré inequality are established for the one-dimensional Wright-Fisher diffusion processes. The main tool of the study is the coupling by change of measures.