干相转换条件对致密皮层不对称膜结构及透气性能的影响

研究了挥发时间、温度等干相转换条件对聚芳醚砜致密皮层不对称膜形态结构、有效皮层厚度及氮、氢透过性能的影响．表明采用本铸膜液体系，在２０℃左右，很短的挥发时间内即可制得较理想的气体分离膜。     

质心袋模型的球腔近似与低能人-N散射

本文引入唯象的夸克禁闭4-矢势及其质心球腔近似,提出了质心袋模型.在静止质心系上它与 MIT袋模型等价;而加上所谓自由度分离规则后,它似能构成自洽的、满足平移不变与洛仑兹协变的场论.它很容易进行量子化,并可导出以前作为假设引入的有关整体口袋-夸克流的计算方法.     

电场调谐InAs单量子点的发光光谱

采用稳态和时间分辨发光光谱,研究了生长在p-i-n二极管结构内的InAs单量子点发光光谱的电场调谐特性.随着电场强度的增加,观察到量子点中激子发光的Stark 效应.通过选择不同波长的激光线激发量子点样品,发现随着电场强度的增加导致量子点发光强度的减弱,这是由于量子点俘获载流子概率的减小所致,而激子寿命的增加源于电场导致激子的Stark效应. 关键词： InAs单量子点 Stark效应 电子-空穴分离     

分光光度法研究在氯化钠-四丁基溴化铵体系中Au(Ⅲ)与U(Ⅵ)、Ce(Ⅲ)、Mg(Ⅱ)和Cu(Ⅱ)的浮选分离

用分光光度法研究了氯化钠和四丁基溴化铵浮选分离金的行为及与一些金属离子分离的条件。结果表明,当溶液中氯化钠和四丁基溴化铵的浓度分别为2.5×10-3mol/L和4.0×10-4mol/L,pH3.0时,Au(Ⅲ)可与U(Ⅵ)、Ce(Ⅲ)、Mg(Ⅱ)和Cu(Ⅱ)离子定量分离,对合成水样中Au(Ⅲ)的分离和测定,结果满意。     

薄层色谱-光谱联用鉴定金属清洗剂中非离子表面活性剂组分

采用薄层色谱法分离了金属清洗剂。以氯仿∶甲醇(8.5∶1),加适量三乙胺体系为展开剂,碘蒸气显色,所得斑点清晰、无拖尾,结果表明金属清洗剂含6种组分。采用亚甲蓝-氯仿法鉴定表面活性剂的离子类型,该样品中两种组分为阳离子表面活性剂,4种组分为非离子表面活性剂。利用红外吸收光谱法、核磁共振波谱法确定了4种非离子表面活性剂的分子结构。     

白簕叶总黄酮的提取和纯化及其抑菌试验初探

观察白簕叶中总黄酮的抑菌作用。采用微波辅助法从白簕叶中提取黄酮化合物,经HPD-600型树脂纯化,通过圆形滤纸片法和二倍稀释法分别对黄酮提取液进行了抑菌试验和最小抑菌浓度(MIC)的测定。HPD-600型树脂纯化后的黄酮纯度达到21.3%,对3种供试菌的抑菌作用为大肠杆菌金色葡萄球菌芽孢杆菌,随着总黄酮浓度的增加,其抑菌作用也增强。白簕叶总黄酮对大肠杆菌、金色葡萄球菌、和芽孢杆菌的MIC分别为原液的1/4、1/2倍和1倍。本方法为白簕的药用价值开发开辟了新途径。     

光敏剂对肿瘤细胞损伤效应与孵育时间关系的拉曼光谱分析

利用拉曼光谱研究光敏剂与HepG2肝癌细胞不同孵育时间的光动力损伤效应。结果表明孵育时间与光动力损伤效应成正相关性,但孵育时间超过一定值,延长孵育时间并不能提高光动力损伤效应。     

Equal-amplitude optical comb generation using multi-frequency phase modulation in optical fibers

<正>We theoretically analyze and experimentally demonstrate a method of generating equal-amplitude optical comb exploiting multi-frequency phase modulation.The theoretical analysis shows that 4n-1 equal-amplitude spectral lines can be obtained when the modulation signal comprises n frequency components including the fundamental frequency and the odd harmonic frequencies,and 2n+1 equal-amplitude spectral lines can be obtained when the modulation signal comprises n frequency components including the fundamental frequency and the even harmonic frequencies.Then,we numerically simulate the spectra of 5,7,9,and 11 equal-amplitude spectral lines,respectively,which are also obtained in experiments with frequency separation of 30 MHz and flatness of better than 0.3 dB.     

Uptake of transferrin-conjugated quantum dots in single living cells

We study the uptake and distribution of transferrin （Tf）-conjugated CdSe/CdS/ZnS quantum dots （QDs） in single living HeLa cells with both fluorescence confocal microscopy and three-dimensional （3D） reconstruction technique. By increasing the co-incubation time or the dosage of QDs-Tf, we find that the uptake of QDs-Tf bioconjugates in the cells increases correspondingly, but with different uptake rates. Additionally, the distribution of QDs-Tf, in single live HeLa cells is time dependent. To our knowledge, this is the first study on quantitatively analyzing the uptake and distribution of bioconjugated QDs in single living cells. Such QDs nanoplatform can be further modified for developing biomedical evaluation tool in cancer diagnosis and targeted drug delivery.     

Fluorescence lifetime imaging of molecular rotors to map microviscosity in cells

Fluorescence liftime imaging （FLIM） of modified hydrophobic bodipy dyes that act as fluorescent molecular rotors shows that the fluorescence lifetime of these probes is a function of the microviscosity of their environment. Incubating cells with these dyes, we find a punctate and continuous distribution of the dye in cells. The viscosity value obtained in what appears to be endocytotic vesicles in living cells is around 100 times higher than that of water and of cellular cytoplasm.Time-resolved fluorescence anisotropy measurements also yield rotational correlation times consistent with large microviscosity values. In this way, we successfully develop a practical and versatile approach to map the microviscosity in cells based on imaging fluorescent molecular rotors.