衬钽管石墨炉原子吸收法测定痕量镓时基体改进剂的研究及应用

提出用钒和铜混合基体改进剂衬钽管石墨炉原子吸收测定镓的方法。衬钽管使镓的灵敏度提高6倍左右,钒和铜混合基体改进剂不仅能进一步提高灵敏度,而且能提高灰化温度,降低原子化温度,增强抗干扰能力。测定 GSD 标准样品中的镓时,不需对样品进行预分离即可直接进行测定,结果与参考值相符。     

苯、甲苯、一氯代苯对含水卵磷脂液晶结构影响的SAXS研究

苯及其衍生物甲苯,一氯代苯都是重要的有机试剂和化工原料,也是对人体有害的有机物。为了了解这些有机试剂对处于生物液晶态的生物膜毒害的机理,我们以含水卵磷脂组成的液晶体系作为人工模型用小角X射线散射(SAXS)方法探讨这些有机试剂对它们结构的影响。关于苯或其它非极性有机介质与含水卵磷脂形成液晶体系及其结构模型前人有一些报导。     

用正电子湮没寿命谱法研究锡镀层缺陷

光亮镀锡工艺由于成本低、无毒、镀层稳定性好而广泛应用于电子元器件引线的电镀.但因锡镀层与基体之间会发生原子的相互扩散,致使产品在储存、焊接或使用期间因温度效应而使某些重要的物理和化学性能,如钎焊性、导电性和防腐性变差。金属界面原子的热扩散行为与金属晶体的结构缺陷密切相关,因此应用正电子湮没寿命谱法研究锡镀层在热处理过程中缺陷的运动规律,在理论和工艺方面都具有重要的意义。     

载镍沸石上NH3-TPD脱附峰的非酸性探讨

NH_3-TPD技术表征固体催化剂的酸性似乎已很成熟,其实不然。如该技术表征HZSM-5沸石时,有作者观察到773K左右的高温脱氨峰,而有些作者则检测不到。诚然,各作者间所用试样及预处理条件等存在差异,但实验装置和实验操作条件不同带来的影响也不可忽视。此外,该技术在用于表征一些新的较复杂的催化剂时,其程脱谱也会呈现出新现象,这些现象有时是不能通过酸性来解释的,这是因为NH_3作为探针分子不仅具有碱性,同时还有还原性和配位性。本文对载镍沸石上NH_3-TPD谱图中出现的某些新峰进行了剖析和归属。     

Preparation and crystal structure of Nb6.74 Ta5.26S4 – a new compound in the ternary system Ta?Nb?S

Nb_6.74Ta_5.26S₄ has been prepared by high temperature techniques. The crystal structure has been determined from single crystal X-ray diffraction data (R/R_w = 0.0588/0.0655). The compound crystallizes in the orthorhombic space group Pnma with unit cell dimensions a = 959.11 (26) pm, b = 336.37 (10) pm, and c = 3282.51 (74) pm. The orthorhombic cell contains four formula units. Its structure is similar to that of Nb-rich sulfides, rather than to that of Ta-rich sulfides. The metal coordinations are capped distorted cubic prisms and pentagonal prisms while the coordinations of sulfur are capped trigonal prisms.     

三碳菁染料的研究

三碳菁染料的吸收在近红外区,可用作卤化银感光材料的红外增感染料,近年来在红外激光染料和光信息记录介质等方面也得到了开发及应用。在多甲川链上引入桥环可提高染料的稳定性。本文合成了9种含芳胺基取代的桥链三碳菁,讨论染料结构与其增感性能关系。     

PP/LDPE共混体系的辐射效应

研究了在多官能团单体—三烯丙基异氰脲酸酯存在下ＰＰ／ＬＤＰＥ共混体系接受γ－辐射的效果。用溶解度参数和ＴＥＭ技术评估了共混体系的相容性与多官能团单体在共混体系中的分布，并用ＳＥＭ、ＤＳＣ、动态力学等方法对共混体系相容性进行了表征。结果表明，ＰＰ／ＬＤＰＥ是不相容的共混体系，三烯丙基异氰脲酸酯主要分布在共混体系的相界面区域，辐照强化了共混体系的相间结合，增加了界面厚度，改善了共混体系的相容性。     

Isolation,spectra, structure,and ring-opening polymerization of strained macrocyclic aryl(ether ketone) dimer

Macrocyclic arylene ether ketone dimer was isolated from a mixture of cyclic oligomers obtained by the nucleophilic substitution reaction of bisphenol A and 4,4′-difluorobenzophenone and easily polymerized to high molecular weight linear poly-(ether ketone). The cyclic compound was characterized by FTIR, ¹H- and ¹³C-NMR, and single-crystal x-ray diffraction. Analysis of the spectral and crystal structure reveals extreme distortions of the phenyl rings attached to the isopropylidene center and of the turning points of the molecular polygons. The release of the ring strain on ring-opening combined with entropical difference between the linear polymer chain and the more rigid macrocycle at temperatures of polymerization may be the proposed motivating factors in the polymerization of this precursor to high molecular weight poly(ether ketone). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1753–1761, 1997     

Preparation of a piezoelectric immunosensor for the detection of Salmonella paratyphi A by immobilization of antibodies on electropolymerized films

 To obtain new coatings for the preparation of piezoelectric immunosensors, the anodic polymerization of o-aminophenol (oAP), o-phenylenediamine (oPD) and m-phenylenediamine (mPD) onto a gold-plated crystal has been studied. The possibility of immobilizing an antibody (anti-S. paratyphi A) onto the crystal via the electropolymerized films was investigated. The poly-mPD film gave the best results for immobilizing the antibody. With antibodies crosslinked on the poly-mPD film, a piezoelectric immuno-assay for the detection of S. paratyphi A was proposed. The shift (ΔF=F_20s−F_400s, Hz) between the frequency at 20 s after the addition of sample (F_20s), and that of 400 s (F_400s) was used to construct a calibration graph, and shortening of the assay time was achieved. The S. paratyphi A concentration in the range of 10^5–10⁹ cells/ml can be measured by this method. Received: 9 May 1996/Revised: 6 September 1996/Accepted: 19 September 1996     

Geographic Characterization of Leccinum rugosiceps by Ultraviolet and Infrared Spectral Fusion

Leccinum rugosiceps is an edible mushroom belonging to genus Leccinum of Boletaceae. Its fruiting bodies are richer in nutrients than many vegetables and fruit. The model of support vector machine was established for the discrimination of L. rugosiceps from regions based on rapid and low-cost ultraviolet and infrared spectroscopies. The mid-level data fusion was performed by support vector machine. Compared to a single spectroscopic technique, mid-level data fusion provided higher accuracy by selecting the most significant variance from data matrixes based on partial least squares discriminant analysis. The accuracy of the classification of samples in the calibration and test sets were 85.00 and 94.74%, higher than separate measurements by ultraviolet or infrared spectroscopy. This approach has applications for authentication and quality assessment of L. rugosiceps.