聚酰亚胺薄膜结构研究Ⅱ

以小角激光光散射、偏光显微镜、X光衍射、电子显微镜、力学性能测定及红外光谱等方法研究了几种聚酰亚胺薄膜的聚集态结构。结果表明,它们在取向状态、球粒和链球结构、表面状况及球晶结构等方面有明显差异,而化学组成相同,因此认为聚集状态的这些差异是导致力学性能不同的主要原因.文中还提出方位角Q_d可作为检测PI薄膜取向状况的参照指标.     

Study of Immunoassay Methods for Recombinant Human Erythropoietin （rhEPO） Using Competitive ELISA

Two different immunoassay methods,competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) and amplificative competitive indirect ELISA(ACI-ELISA) using biotin-avidin complex system were studied to detect rhEPO.The linear ranges were 50-20000ng/mL and 10-50000ng/mL for CI-ELISA and ACI-ELISA,respectively.The low detection limits of CI-ELISA and ACI-ELISA were 62.8ng/mL and 8.5ng/mL,respectively.     

Determination of nickel,cobalt, copper and uranium in water by cathodic stripping chronopotentiometry with continuous flow

The potential of cathodic stripping chronopotentiometry for the determination of trace metals in a continuous-flow system is investigated. An automated analyzer with a fast rate of data acquisition (250 kHz) is described. The cathodic scans are preceded by adsorptive collection of surface-active metal complexes on the hanging mercury drop electrode. The scans are done by passing a constant current of between 0.8 (in deaerated solution) and 60 μA (in solutions saturated with air) through the working electrode. Copper, uranium, and nickel can be determined in the presence of dissolved oxygen, but the sensitivity for nickel is then much reduced. The sensitivity of stripping chronopotentiometry in the presence of dissolved oxygen is similar to that of fast linear-sweep voltammetry in the absence of dissolved oxygen. The limits of detection were 0.1 nM Ni, 0.1 nM Co, 1.8 nM Cu and 1.6 nM U, when the measurements were preceded by 60-s stirred adsorption; in the presence of dissolved oxygen the limit of detection for nickel was higher at 0.6 nM, and cobalt could not be determined, as its peak was located on top of the oxygen peak. The determinations of copper and uranium were not adversely affected by dissolved oxygen. The limits of detection can be lowered further by using a prolonged collection period (up to 300 s). The technique was successfully tested by measuring nickel with continuous flow in water pumped on board of a small vessel in the Tamar estuary.     

溶剂热法合成蜂巢状氧化镍及其电化学电容性能

利用N，N-二甲基甲酰胺(DMF)为溶剂的溶剂热法制备了蜂巢状氧化镍，反应过程中DMF既做溶剂又做沉淀剂。研究了不同制备条件对NiO形貌及电化学性质的影响，并用X-射线衍射(XRD)、扫描电子显微镜(SEM)以及循环伏安(CV)技术进行了表征。结果表明，300 ℃热处理得到的氧化镍，10 mA电流下单电极比电容达460 F·g^-1。     

合成因素对V-AlPO4-5骨架钒含量和催化苯氧化性能的影响

水热法合成了V-AlPO4-5分子筛，用XRD和FT-IR对样品进行了表征．以纯V-AlPO4-5分子筛为基准，用样品单位晶胞体积的膨胀程度和红外谱图中骨架振动峰向低波数方向位移程度的大小为指标，定性地探索了钒源、加料方式、钒加入量和晶化时间等合成因素对于V-AlPO4-5分子筛中骨架钒含量的影响．结果表明以V2O5为钒源、采用(V P H2O) Al R的加料方式，V／(Al P)=1／80，200℃下水热晶化48h后得到的V-AlPO4-5分子筛中骨架钒含量最高．H2O2氧化苯制苯酚的活性实验结果表明，苯酚收率和H2O2分解率同V-AlPO4-5骨架钒含量具有明显的正相关性．溶剂效应表明反应机理是羟基自由基机理．     

Theory and computation of electron transfer reorganization energies with continuum and molecular solvent models

Contemporary continuum-based models of solvation in polar media are surveyed and assessed, with special focus on non-equilibrium solvation. A new hybrid approach combining molecular-level treatment of inertial solvent response, and inclusion of inertialess solvent response at the continuum level, is presented and illustrated in terms of calculated equilibrium solvation free energies for small molecular ions and reorganization free energies for model dumbbell systems.     

Laser multiphoton ionization in a time-of-flight mass spectrometer: vibronic/mass spectra of triethylenediamine from 425 to 560 nm

Resonance-enhanced multiphoton ionization (REMPI) fragmentation patterns are obtained as a function of laser wave-length using a new, computer-controlled, high-resolution time-of-flight laser mass spectrometer system. REMPI mass spectra for triethylenediamine show extensive fragmentation, the pattern dependent upon the particular two-photon resonance (doorway state) selected.     

A fast separation for antimony produced in heavy-ion induced fission

Fission fragments from heavy ion induced fission were stopped in thin magnesium foils. A fast procedure based on evolution of stibine was developed to separate the antimony isotopes embedded in the foil. A separation system, and a glass pressure filtration system was constructed for this purpose. The chemical yield measured by three independent methods was 80–90%. The degree of decontamination from other fission products was >10². The whole separation took eight minutes.     

In Vivo Monitoring of Neurotransmitters with Voltammetry and Smallbore HPLC

The temporal and concentration response of microdialysis probes in vivo was characterized. The temporal response was monitored using step changes in dopamine (DA) concentration which were followed with one minute sampling using smallbore HPLC. The response under three conditions was examined: in vitro sampling of DA, in vitro infusion of DA, and local infusion of DA. The dialysate DA concentration stabilized within two minutes after each change. These results suggest that relatively fast changes in DA levels in tissue can be followed by microdialysis probes. The rapid stabilization also suggests that the DA concentration profile does not extend very far from the probe. To characterize the concentration response, the linearity of the gain or loss of DA diffusing between the probe and tissue was determined. The difference in the inflow and outflow concentrations was plotted as a function of the inflow concentration. The correlation coefficient of the linear regression curve was 0.99. The zero point intercept, the extracellular concentration of DA, was 3.8 nM and the slope, or recovery, was 63.4%. There was no break at the zero point which is indicative of symmetrical diffusion into and out of the probe.     

99mTcN核标记的新型心肌灌注显像剂的研究

通过配体交换反应制备了[99mTcN(PNP5)(DEDC)]+和[99mTcN(PNP5)(DPODC)]+两种新配合物, 其放化纯度均大于90%. 生物性能研究结果表明: 两种配合物在小鼠心肌中的初始摄取高, 肝、肺等非靶组织清除快, 靶/非靶比高, 有利于早期心肌显像. 其中, [99mTcN(PNP5)(DEDC)]+在小鼠中的性质较优, 且其在狗体内的性质接近99mTc-tetrofosmin, 有望成为一种新型心肌灌注显像剂.