70个南天旋涡星系等值厚度的测定

利用彭秋和提出的方法以及分析星系的旋涡图样 ,得到 70个南天旋涡星系的等值厚度 ,这些星系的图象是从北京天文台兴隆观测站Palomar天图数字光盘 (theDigitizedSkySurvey)中读出的 .为了得到星系的最佳倾角 (星系平面与天球切平面之间的夹角 ) ,把用最小二乘法拟合得到的对数螺线画在星系图象上与旋臂进行比对 ,反复调节星系的倾角 ,使拟合得到的对数螺线能很好地与旋臂吻合 ,从而得出星系的最佳倾角.     

Effect of glass bead packing on the fibrillation of liquid‐crystalline polymer in polycarbonate

Polycarbonate (PC) was melt blended with small amount of liquid‐crystalline polymer (LCP) and various contents of glass beads (GB) having different diameters. The rheological measurements indicated that the GB addition increased the viscosity ratio and seemed unfavorable to the LCP fibrillation. However, the morphological observation showed that the LCP fibrillation was promoted by the GB addition and varied with the GB packing. With the increased GB packing by increasing the GB content and/or decreasing the GB diameter, LCP deformed from spheres and ellipsoids into stretched ellipsoids at lower shear rates and into long fibrils at higher shear rates. Although higher content of smaller GB jammed into the larger LCP droplets and inhibited the LCP fibrillation, very long LCP fibrils formed at higher shear rates at a high enough packing of GB. The relationship between GB packing and LCP fibrillation revealed two kinds of hydrodynamic effects of GB promoting the LCP fibrillation: at lower GB packing, the shear flow was enhanced by the high local shear between GB, in quantity; and for a high enough GB packing, the shear flow was changed, in quality, into elongational flow, which was more effective for the LCP fibrillation. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1020–1030, 2006     

A new on-line sample preparation system for the liquid chromatography/time-of-flight mass spectrometry simultaneous analysis of pesticides in river water.

Current on-line solid-phase extraction methods combined with HPLC for shortening the clean-up operation are not suitable for simultaneously detecting compounds that have a wide variety of hydrophobicities. To solve these problems, we designed a new on-line sample preparation system. The system consists of an eluting pump, a mixing TEE connector, a 10-port 2-position valve and a solid-phase extraction precolumn. The eluate from the precolumn is diluted with a weak solvent from the HPLC at the TEE connection to load low hydrophobic compounds onto the analytical column. The proposed on-line sample preparation system was successfully applied to the simultaneous analysis of 21 pesticides in river water using LC/TOF-MS. In this method, the recoveries from river water samples were 67 to 126% (mean 83%), the reproducibility (CV%) was in the range from 1.1 to 11% (mean 5.6%), the calibration curve was linear in the range from 1 ppb to 500 ppb (r > 0.999) and the detection limits (S/N = 3) were in the range from 0.0034 ppb (daimuron) to 3.3 ppb (oxine-copper).     

A highly sensitive and rapid assay for protein determination in human urine and penicillin using a Rayleigh light-scattering technique with benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic acid sodium salt.

A simple and sensitive method was conducted for the determination of trace amounts of proteins with benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic acid sodium salt (azophloxine, AP) using a Rayleigh light-scattering (RLS) technique. At pH 2.60 and in the presence of an emulsifier OP microemulsion, the RLS of AP can be greatly enhanced by proteins, owing to the interaction between AP and protein. The enhanced intensity is proportional to the concentration of proteins. Four proteins, including bovine serum albumin (BSA), human serum albumin (HSA), lysozyme (Lys) and gamma globulin (gamma-G) have been tested. For example, the linear range of BSA was 0 - 0.06 microg mL(-1) with detection limits of 2.38 ng mL(-1). The method was applied to the analysis of protein in human urine and penicillin samples with satisfactory results. The relative standard deviation was in all instances less than 4.0%, and the recovery was in the range of 97.5 - 104%.     

Novel photoswitching dithienylethenes with ferrocene units

Two novel dithienylethenes with ferrocene units were synthesized by Wittig reaction. The structure of 2a has been established by X‐ray diffraction studies. They could reversibly interconvert between two thermally stable forms, an open and a closed one, using light of different wavelengths as triggers. Copyright © 2006 John Wiley & Sons, Ltd.     

铁电体表面效应的唯象理论及其与横场Ising模型的关系

分析了铁电体横场Ising模型与Landau唯象理论的关系,得出了有表面的铁电体的Landau自由能表达式,指出原有的表达式中面积分部分仅含与极化平方成正比的项只在特殊情况下成立,一般情况下还应包含与极化四次方成正比的项.利用所得出的自由能表达式,计算了铁电薄膜自发极化和Curie温度与厚度的关系,使原先用唯象理论不能理解的一些实验现象得到了解释     

Terminally functionalized polyisobutylene oligomers as soluble supports in catalysis

A new phase selective hydrocarbon soluble polymer support is described.     

A light-driven rotaxane molecular shuttle with dual fluorescence addresses

[reaction: see text] A molecular shuttle containing an alpha-CD macrocycle, an azobenzene unit, and two different fluorescent naphthalimide units was synthesized. The cis-trans photoisomerization of the azobenzene unit resulted in the motion of the CD macrocycle on the track. Because of the easy regulation and full reversibility of the fluorescence change of the two stopper units, the molecular shuttle could be used as a molecular storage medium or switch with all-optical inputs and outputs.     

Heteroallen-komplexe des molybdänocens

Reactions of the extremely labile molybdenocene olefin complexe Mo(η⁵-C₅H₅)₂[(Z)-C₆H₅CH=CHC₆H₅] with heteroallenes X=C=Y (X=C=Y = CS₂, (p-tolyl)NCN(p-tolyl), (C₆H₅)₂CCO) gives the corresponding heteroallene complexes of molybdenocene Mo(η⁵-C₅H₅)₂(X=C=Y) in high yields. Spectroscopic data clearly indicate a dihapto-coordination of the heteroallenes via the C=X bond (X = O, S, N).