醋酸甲地孕酮的荧光分析法研究

基于醋酸甲地孕酮与浓H2SO4反应后水解产物的荧光性质建立了一种测量醋酸甲地孕酮的荧光光度分析新方法.系统地研究了不同环境介质和表面活性剂对产物荧光性质的影响,提出了醋酸甲地孕酮被氧化及荧光增强的作用机理.本法检测限为1. 04×10-6mol·L-1,荧光强度与醋酸甲地孕酮浓度在0～4.68×l0-5mol·L-1范围内呈良好线性关系,方法相对标准偏差为5.6%.     

铸膜液溶剂体系的物理参数与BCA不对称膜的透气性

铸膜液的溶剂体系（溶剂和非溶剂）对不对称膜形态的形成有重要作用。为了探索溶剂和透气性间的关系，本文考虑到了制备ＢＣＡ梯度密度不对称膜的各种溶剂的一系列物理参数，得到了一些定性结果，并指出了更全面、明确、解释两者关系的研究方向。     

Beam-based calibrations of the BPM offset at C-ADS Injector Ⅱ

Beam-based BPM offset calibration was carried out for Injector II at the C-ADS demonstration facility at the Institute of Modern Physics(IMP), Chinese Academy of Science(CAS). By using the steering coils integrated in the quadrupoles, the beam orbit can be effectively adjusted and BPM positions recorded at the Medium Energy Beam Transport of the Injector II Linac. The studies were done with a 2 m A, 2.1 Me V proton beam in pulsed mode.During the studies, the "null comparison method" was applied for the calibration. This method is less sensitive to errors compared with the traditional transmission matrix method. In addition, the quadrupole magnet's center can also be calibrated with this method.     

乙酸乙酯合成反应的实时在线拉曼光谱测量

本文报道一种用于在线拉光谱测量的技术。可以在工业生产过程中对产品的成分和工作条件进行实时的监测,在本实验中,用我们自己研制的光纤探头,配合现有的拉曼光谱装置对合成乙酸乙酯的化学反应过程进行了实时跟踪测量。得到了反应过程中乙醇-,乙酸和乙酸乙酯的拉曼光谱,从谱图分析了它们的特征峰与时间的关系,从而可由这些结果确定在此实验条件下反应物与生成物的浓度随时间的变化,进而可确定反应过程完成的时间。     

Structural effects on water formation from coadsorbed H + O on Rh(100)

The effect of adsorbate coverage, adsorption sequence and temperature on the structure, composition and reactivity of coadsorbed layers, produced by dissociative adsorption of O₂ and H₂ at 200 K on a Rh(100) surface, has been studied by combined TPD, XPS and LEED measurements. The emphasis is on the impact of the structure and composition of the mixed O + H layers on the synthesis of hydroxyl and water as a result of the O + H surface reaction. The difference in the O 1s binding energies of adsorbed O (529.9 eV) and OH species (530.8 eV) was used as a fingerprint to monitor the formation of the OH species. The H₂O TPD spectra show substantial variations of the desorption temperature range and the amount of water evolved with coadsorbate coverage and structure: from 270 to 350 K and from 0 to 0.08 ML, respectively. It has been found that dense O + H adlayers, where the O coverage is in the range 0.25-0.4 ML, favor the formation of stable OH species. The maximum amount of stable hydroxyl OH species ( 0.16 ML) can be produced by heating of these dense adlayers to 260 K. This results in reordering of the adspecies to form a new O + OH − (2 × 6) structure, where hydroxyls react readily to evolve 0.08 ML of water in a sharp desorption peak at 280 K. The effect of the adlayer density and restructuring on the production of OH and H₂O is discussed.     

Damping Properties of Blends Based on EVM

The mechanical and damping properties of blends of ethylene-vinyl acetate rubber (VA content >40% wt) (EVM)/ethylene-propylene-diene copolymer (EPDM) and EVM/nitrile butadiene rubber (NBR), both with 1.4 phr BIPB (bis (tert-butyl peroxy isopropyl) benzene) as curing agent, were investigated by dynamic mechanical analysis (DMA). The effect of added polyvinyl chloride (PVC), amido donor N-cyclohexyl-2-benzothiazole sulfonamide (CZ), and dicumyl peroxide (DCP) as a substitute curing agent, on the damping and mechanical properties of both rubber blends were studied. The results showed that in EVM/EPDM/PVC blends, EPDM was immiscible with EVM and could not expand the damping range of EVM at low temperature. PVC was miscible with EVM and dramatically improved the damping property of EVM at high temperature while keeping good mechanical performance. In EVM/NBR/PVC blends, PVC was partially miscible with EVM/NBR blends and remarkably widened the effective damping temperature range (EDTR) from 41.1°C for EVM/NBR to 62.4°C. Curing agents BIPB and DCP had a similar influence on EVM/EPDM blends. DCP, however, dramatically raised the height of tan δ peak of EVM/NBR = 80/20 and expanded its EDTR to 64.9°C. CZ had no obvious influence on the EVM/EPDM blends cured with BIPB. However, a small content of CZ enlarged the tan δ peak of EVM/NBR = 80/20 in both height and width, but at the cost of a deterioration of mechanical performance.     

Fabrication and Optimization of Poly(vinyl alcohol)/Zirconium Acetate Electrospun Nanofibers Using Taguchi Experimental Design

This paper presents an investigation regarding poly(vinyl alcohol)/zirconium acetate (organic–inorganic) (PVA/Zrace) nanofibers prepared by electrospinning which could be used as a precursor for fabricating ceramic metal oxide nanofibers. The effect of some processing variables, including polymer solution concentration, tip to collector distance and applied voltage of electrospinning, and the amount of Zrace and their interactions, on the diameter of the nanofibers were studied. Taguchi experimental design and a statistical analysis (ANOVA) were employed and the relationship between experimental conditions and yield levels determined. It was concluded that to obtain a narrow diameter distribution as well as maximum fiber fineness, a polymer concentration of 10 wt%, tip to collector distance of 18 cm and applied voltage of 20 kV variables were the optimum. Furthermore, it was also concluded that the ratio of Zrace (6 g) to PVA solution (10% wt) played an important role for achieving the minimum fiber diameter. Under these optimum conditions, the diameters of the electrospun composite fibers ranged from 86 nm to 381 nm with a diameter average of 193 nm. The experiments were done with Qualitek-4 software with “smaller is better” as the quality characteristics. The optimized conditions showed an improvement in the fibers diameter distribution and the average fibers diameter showed good resemblance with the result predicted using the Taguchi method and the Qualitek-4 software. The ANOVA results showed that all factors had significant effects on the fibers diameter and distribution, but the effect of PVA concentration and zirconium acetate were more significant than the other factors.     

Sonochemical synthesis and characterization of new one-dimensional manganese(II) coordination polymer nanostructures

A new Mn(II) coordination polymer, [Mn (L₁)₂(NCS)₂]_n (1) [L₁ = 3,4-bis(4-pyridyl)-5-(2-pyridyl)-1,2,4-triazole] was synthesized by the reaction of ligand L₁ and mixtures of manganese(II) acetate and potassium thiocyanate using the heat gradient method. Compound 1 has been characterized by IR spectroscopy, elemental analyses and X-ray crystallography. The crystal structure of compound 1 was determined by single-crystal X-ray diffraction and shows a new interesting one-dimensional coordination polymer. Nanostructures of compound 1 have been synthesized by sonochemical method. The products were characterized by X-ray powder diffraction, scanning electron microscopy (SEM), and IR spectroscopy. The thermal stability of nano particles of compound 1 was studied by thermal gravimetric and differential thermal analyses.     

Multifunctional human serum albumin in the surface‐enhanced Raman spectroscopy of porphyrin: demetalation promoter,molecular spacer and stabilizer

Human serum albumin (HSA), a model protein, was introduced to the surface‐enhanced Raman spectroscopy (SERS) of cationic porphyrin 5,10,15,20‐tetrakis(1‐methyl‐4‐pyridyl)‐21H,23H‐porphine (H₂TMPyP4). HSA was found to have a great influence not only on Ag nanoparticle aggregation state but also on the interaction between Ag nanoparticle and H₂TMPyP4 molecules. In the (H₂TMPyP4‐Ag colloid)/HSA system, addition of H₂TMPyP4 to Ag colloid led to a quick Ag colloid aggregation, and subsequent HSA addition could stabilize this system. The SERS spectrum was dominated by a combination of Ag(II)TMPyP4 and free base H₂TMPyP4. More interestingly, a photoinduced demetalation of Ag(II)TMPyP4 to free base H₂TMPyP4 was observed in the (H₂TMPyP4‐Ag colloid)/HSA system. This demetalation process was partially reversible when the laser was turned off or the laser power was reduced. In this case, HSA acts as both a stabilizer and a demetalation promoter. In the (HSA‐H₂TMPyP4)/Ag colloid system, when H₂TMPyP4 was premixed with HSA prior to the Ag colloid addition, no obvious Ag colloid aggregation appeared, and the SERS spectrum was just characteristic of free base H₂TMPyP4. In this case, HSA is proposed to function as both a stabilizer and a molecular spacer. Copyright © 2010 John Wiley & Sons, Ltd.     

Magneto-optical single dot spectroscopy of GaSb/GaAs type II quantum dots

We have investigated magneto-optical properties of GaSb/GaAs self-assemble type II quantum dots by single dot spectroscopy in magnetic field. We have observed clear Zeeman splitting and diamagnetic shift of GaSb/GaAs quantum dots. The diamagnetic coefficient ranges from 5 to 30 μeV/T². The large coefficient and their large distribution are attributed to the size inhomogeneity and electron localization outside the dot. The g-factor of GaSb/GaAs quantum dots is slightly larger than that of similar type I InGaAs/GaAs quantum dots. In addition, we find almost linear relationship between the diamagnetic coefficient and the g-factor. The linear increase of g-factor with diamagnetic coefficient is due to an increase of spin-orbit interaction with dot size.