Large negative Goos-H(a|¨)nchen shift from a wedge-shaped thin film

The analytical expression for the complex amplitude of light reflected from a wedge-shaped thin film is derived. For plane wave incidence, a simple ray tracing approach is used to calculate Goos-H(a|¨)nchen (GH) shifts; and for non-plane wave incidence, for example, a Gaussian beam, the angular spectrum approach of plane wave is used in simulation. The two approaches predict that a wedge-shaped thin film can produce large negative longitudinal GH shifts. Although the reflectivity is small near the condition...     

Synthesis of Novel Chiral Diol Ligands for the Enantioselective Reactions

The chiral diols ((,(,((,((-Tetraaryl-1,3-dioxolane-4,5-dimethanols) have been used for the formation of cyclic titanates and similar derivatives of Mg, Al and Zr. These complexes of oxophilic metal centers were employed in catalytic and stiochiometric enantioselective reactions such as enantioselective addition reactions of carbon-centered nucleophiles to aldehydes1, [2+2] cycloadditions2, and Diels-Alder reactions3. So far, the two hydrogen atoms of all this type of diols are in trans form…     

W18Cr4V

The frictionand wear characteristics of the surfa ce compound layer of W18Cr4V steel by combined treatment of ion nitrocarburizing-ion sulphurizing were investigated. The friction coefficient of the compound l ayer against GCr15 steel was determined witha block-ring friction tester. The wear test was carried out with a reciprocating wear tester. The worn surface was analyzedby scanning electron microscopy(SEM). The experimental results reveale d that the friction coefficient was lower for treatedW18Cr4V steel against GCr1 5 steel. The wear resistance of the compound layer was higher because the nitroc arbonide andthe sulphide in the compound layer were capable of friction-reduct ion and adhesion-inhibition.     

Coupling Reaction of 4-Chloro-7-H-Pyrrolo[2,3-d]Pyrimidine with 2,3,5-Tri-O-Acetyl-β-D-Ribofuranosyl Chloride

Tubercidin (4-amino-7--D-riobofuranosyl-7-H-pyrrolo[2,3-d]pyrimidine) 1, an antibio-tic substance produced in the culture broth of Streptomyces tubericidus1, is an adenosine analog in which N-7 is replaced by a carbon atom. It has attracted much attention due to the biological activities for the growth inhibition of certain tumors, and many derivatives of tubercidin have been synthesized2-5.For the synthesis of tubercidin analogs, 4-chloro-7-H-pyrrolo[2,3-d]pyrimidine-2,3,5-tri-O-acetyl--D-r…     

A study on methane coupling to acetylene under the microwave plasma

By optimizing the microwave chemistry reactor made of the rectangular waveguide resonator,the methane conversion(the maximum 93.7%),the C2 hydrocarbon yield(the maximum 91.0%) and the acetylene yield(the maximum 88.6%) were all greatly increased under the microwave plasma.Furthermore,for the optimal reactor,the change of the methane conversion and the C2 hydrocarbon yield is little within the range of the pressures in the experiments.The C2 hydrocarbon is mainly made up of acetylene,and the selectivity for ...     

Discovery of a Novel 5-HT_(2A) Inhibitor by Pharmacophore-based Virtual Screening

The serotonin 2A(5-HT2A) receptor has been implicated in several neurological conditions and potent 5-HT2A antagonists have therapeutic effects in the treatment of schizo phrenia and depression.In this study,a potent novel 5-HT2A inhibitor 05245768 with a Ki value of (593.89±34.10) nmol/L was discovered by integrating a set of computational approaches and experiments(protein structure prediction,pharmacophore-based virtual screening,automated molecular docking and pharmacological bioassay).The 5-HT2A recept...     

Loading of cold ~(87)Rb atom with diffuse light in an integrating sphere

<正>Cold ~(87)Rb atom's loading in an integrating sphere with diffuse light is analyzed theoretically and experimentally. The experimental results show that diffuse light cooling has the greatest efficiency to cool the most atoms when the red detuning between the frequencies of cooling light and atom transition is about 3.3r(Γis the natural linewidth,6.065 MHz).Theoretical analysis using rate equation and numerical calculations on the cold atom number and loading time agree with the experimental results.This integrating sphere cooling would be a novel method for cooling atoms and lead to a new and robust cold atom source for atomic clock.     

Λ-Shaped optoelectronic materials based on Trger's base

Trger's base (TB) is a well-known chiral molecule with rigid concave shape that makes it applicable in different areas such as superamolecular chemistry,molecular recognition,biological labeling,and so on.In this article,we briefly summarize some recent research progress in the optoelectronic properties of novel TB analogues and their applications in optoelectronic field with emphasis on the developments achieved in our group.     

Structure Characteristic and Catalase Activity of Vitreoscilla Hemoglobin Bound with Membrane

Lipid-bound [VHb(406)] and lipid-free [VHb(402)] wide type Vitreoscilla hemoglobin were separated from E. coli BL21(DE3). The RZ is 3.30 for [VHb(406)] and 3.15 for [VHb(402)], respectively. VHb(406) shows a characteristic absorption band at 626 nm, while VHb(402) shows one at 644 nm, and it has more α-helix than VHb(402). Data of Raman spectra experiment shows under the excitation wavelength 488 nm, υ4 vibration of both VHb(402) and VHb(406) had a pure and strong signal at 1375 cm-1, which proves that iron...     

桂枝的引药作用机制及其对环丙沙星在小鼠体内分布的影响

研究了桂枝和桂皮醛对环丙沙星在小鼠体内分布的影响,并基于此探讨了桂枝作为引药使用的作用机制.实验中将小鼠分为三组,分别灌胃生理盐水、桂枝(50gkg-1)和桂皮醛(0.25mLkg-1),然后对三组小鼠尾静脉注射环丙沙星(20mgkg-1),并以荧光法测定不同时间点小鼠体内各组织中环丙沙星的浓度.结果显示桂枝、桂皮醛均促进了环丙沙星在四肢的分布,桂枝与桂皮醛组相对于生理盐水组可将环丙沙星在四肢的含量提高约40%~200%,证实了桂枝引药到达肢节的作用.桂枝与桂皮醛组对环丙沙星分布情况的影响没有显著性差异,说明桂皮醛很可能是发挥桂枝引药作用的主要物质.