Enantioselective Construction of Functionalized Thiochromans via Squaramide‐Catalyzed Asymmetric Cascade Sulfa‐Michael/Michael Addition

An efficient enantioselective cascade sulfa‐Michael/Michael addition reaction of trans‐3‐(2‐mercaptophenyl)‐2‐propenoic acid ethyl ester with nitroalkenes catalyzed by a chiral squaramide catalyst was disclosed. This cascade reaction afforded thiochroman derivatives with three contiguous stereocenters in high yields (up to 94%), excellent diastereoselectivities (up to >25:1 dr) and enantioselectivities (up to 99% ee).     

Performance enhancement of straight-bladed vertical axis wind turbines via active flow control strategies: a review

Meccanica - Darrieus-type vertical axis wind turbines (or VAWTs) have the main rotor shaft arranged vertically and the main components can be located at the base of the turbines. Therefore, VAWTs...     

Solid state reactions of nitrogenous heterocyclic compounds (II)

Solid state Michael addition reaction of indole with α, β-unsaturated carbonyl compounds was carried out, by which a series of compounds containing three different heterocyclic groups binding to one carbon atom were ob-tained. In the presence of Lewis acid, indole could undergo the solid state condensation reaction with aromatic ketones and aldehydes or quinones. The solid state reaction showed higher selectivity and yield than solution reaction. The structures of products were identified by IR,¹H NMR, MS. elemental analysis and X-ray crystal analysis. The reac-tion mechanism was also proposed. Project supported by the National Natural Science Foundation of China     

血液中溴敌隆的液相色谱-质谱联用分析

溴敌隆为第一代抗凝血杀鼠剂,由于其中毒潜伏期长（3～5d）,体内检测有一定难度。特别是中毒者经过抢救以后,溴敌隆在其体内的含量降低,因此需要采用高灵敏度的方法进行检测。对生物检材中溴敌隆的分析国内外均有报道,样品处理多为有机溶剂提取,高效液相色谱（HPLC）测定。谭家镒等采用GDX403大孔树脂提取和紫外吸收光谱导数法进行了测定。有关高效液相色谱-质谱联用（HPLC-MS）测定的方法未见报道。     

Preparation of stable second‐order nonlinear optical films by sol–gel technique

A stable nonlinear optical (NLO) film containing “T” type alkoxysilane dye was prepared by sol–gel technology. This crosslinked “T” type alkoxysilane dye was synthesized and fully characterized by FTIR, UV–Vis spectra, and ¹H‐NMR. Followed by hydrolysis and copolymerization processes of the alkoxysilane with γ‐glycidoxypropyl trimethoxysilane (KH560) and tetraethoxysilane (TEOS), high quality inorganic–organic hybrid second‐order NLO films were obtained by spin coating. The “T” type structure of the alkoxysilane was found to be effective for improving the temporal stability of the optical nonlinearity due to the reduction in the relaxation of the chromophore in the film materials. Copyright © 2009 John Wiley & Sons, Ltd.     

PEO-LiC104-SiO2-SCA体系电化学性能研究

选用硅烷偶联剂(SCA)对聚环氧乙烯(PEO)基固态聚合物电解质体系进行改性.通过XRD,DSC,SEM,FTIR,EIS 和拉伸性能测试等方法对材料进行了表征,考察了SCA对电解质电化学性能和力学性能的影响;对SCA的作用进行了分析.结果显示,SCA的加入显著降低了体系的结晶度,材料的电化学性能和力学性能得到了明显的改善.PEOB-LiC1Oa-5%SiO2-SCA体系室温电导率达到9.0×10-4S/cm,屈服强度达到2.04MPa(25℃).同时,SCA使电解质膜表面变得更为光滑、致密,这有利于降低与电极片间的接触阻抗.     

复相系平衡条件及平衡稳定性条件的分析

复相系平衡条件及平衡稳定性条件的分析曾丹苓（重庆大学热力工程系重庆６３００４４）关键词复相系，平衡条件，平衡稳定性条件１引言汽液相变是工程上常见的现象，它是一个复杂的物理过程，涉及到传热传质、相转变、表面现象、流体流动及工质热物性等领域，但从热力学的...     

Permeability enhancement by induced displacement current in magnetic material with high permittivity

Based on a analytical model, this paper reveals that instead of demagnetization, the induced displacement current in a Mn–Zn ferrite core due to its high permittivity can produce a magnetic field that effectively adds to the incident magnetic field in the low-loss frequency region. This leads to a resultant magnetic field being larger than incident field in magnitude, and results in measured permeability being higher than its intrinsic value in the low-loss frequency region. It is also found that such effect is more pronounced in large core than in small core. With increasing frequency and consequently the core being more lossy, the induced magnetic field due to both conductivity and imaginary part of complex permittivity demagnetize the magnetic material and counteracts the incident magnetic field. In consequence, the measured real part of complex permeability becomes smaller than its intrinsic value. The larger the core dimension, the smaller the real part of complex permeability is. These conclusions based on the numerical analysis are in good agreement with the experimental observation in the aspect of change tendency of permeability versus frequency.     

A New Nano Design for Implementation of a Digital Comparator Based on Quantum-Dot Cellular Automata

International Journal of Theoretical Physics - Quantum-dot is the result of elastic relaxation which has a straight relationship with the optical and electronic aspects of the quantum-dot-based...     

Viable but nonculturable cells used in biosensor fabrication for long-term storage stability

In this paper, we first reported the viable but nonculturable (VBNC) cells used for fabricating biosensor. The organic-inorganic hybrid material composed of silica and the grafting copolymer of poly(vinyl alcohol) and 4-vinylpyridine (PVA-g-P(4-VP)) was used to immobilize microbial cells for biosensor fabrication. The VBNC cells were formed after the hybrid material dried, showing the cell walls were sacrificed. With the intracellular enzymes as core and the “sacrificed” cell walls as shell, the present VBNC cells maybe considered as a core/shell structure. The extracellular material worked as the scaffold for core/shell structure. The core/shell structure and the scaffold structure were demonstrated by single-cell level image analysis using confocal laser scanning microscopy (CLSM). The electrochemical method was adopted for further examining the enzyme activity of VBNC cells. The VBNC cells did not need nutrient treatment and other physicochemical factors for cell growth, which is a significant contribution for storing biosensor. A glucose-glutamic acid biosensor fabricated by the VBNC cells exhibited long-term storage stability for 100 days.