紫外—可见光谱法研究含Schiff碱基双分子膜的构象

测定了不同浓度、不同温度条件下含Ｓｃｈｉｆｆ碱基的单链两亲性化合物在Ｃ１６ＳＢＣ６Ｎ＾＋ＯＨ水溶液的电子吸收光谱。结果表明，两亲性分子在高温低度水溶液中处于较为分散状态，而在低温高浓度水溶液中呈聚集状态。同时，通过量化计算比较，得出了不同聚集态时Ｓｃｈｉｆｆ碱基的构象。     

乙烯基吡咯烷酮—醛酸乙烯酯共聚物对1—苯胺基萘—8—磺酸盐水溶液的荧光...

将荧光探针１－苯胺基萘－８－磺酸盐（ＡＮＳ）加入到乙烯基吡咯烷酮（ＶＰ）－醋酸乙烯酯（ＶＡＣ）共聚物溶液中，共聚物组成分别为ＦＶＰ＝０．８４；０．７４；０．７０；０．５５（以乙烯基吡咯烷酮结构单元的分子数表示）。实验结果表明：ＶＰ－ＶＡＣ共聚物对ＡＮＳ水溶液的荧光强度增强效应与共聚物中乙烯基吡咯烷酮在逻节中的比例有关，其组成为ＦＶＰ＝０．５５的共聚物对ＡＮＳ水溶液有显著的荧光增强效应，相对荧光强度     

手性schiff碱金属配合物N,N‘—双水杨醛缩—1,2—环己二胺合镍（Ⅱ） …

利用经外、拉曼光谱研究一种手性ｓｃｈｉｆｆ碱金属配合物Ｎ,Ｎ’－双水杨醛缩－１,２－环己二胺合镍（Ⅱ）的结构特点。表明（Ｒ,Ｒ）－ＳＡＬＥＮ－Ｎｉ（Ⅱ）和（Ｓ,Ｓ）－ＳＡＬＥＮ－Ｎｉ（Ⅱ）的光谱完全相同,而与外消旋体的光普有很大差别。     

乙烯基吡咯烷酮－醋酸乙烯酯共聚物对1－苯胺基萘－8－磺酸盐水溶液的荧光特性的影响

将荧光探针１－苯胺基萘－８－磺酸盐（ＡＮＳ）加入到乙烯基吡咯烷酮（ＶＰ）－醋酸乙烯酯（ＶＡＣ）共聚物溶液中，共聚物组成分别为ＦＶＰ＝０．８４；０．７４；０．７０；０．５５（以乙烯基吡咯烷酮结构单元的分子数表示）。实验结果表明：ＶＰ－ＶＡＣ共聚物对ＡＮＳ水溶液的荧光强度增强效应与共聚物中乙烯基毗咯烷酮在链节中的比例有关，其组成为ＦＶＰ＝０．５５的共聚物对ＡＮＳ水溶液有显著的荧光增强效应，相对荧光强度比ＰＶＰ均聚物大一倍，而其他组成的共聚物／ＡＮＳ溶液的相对荧光强度只与溶液中ＶＰ结构单元的含量有关。这种现象说明接近等分子比的乙烯基吡咯烷酮－醋酸乙烯酯共聚物与ＡＮＳ分子间形成的过渡态结构有利于能量转移，能产生较高的量子收率，可作为电子转移反应能量转移介质。在生化反应中，可模拟酶反应机理，因而有一定的理论意义和实际意义。     

（7—甲氧基—4—亚甲基）香豆素基—单氮杂18—冠—6的合成及其？…

合成、鉴定了题示光敏离子载体（ＭＭＣ－ＭＡＣ（Ｏ５）。其中不同ｐＨ值水溶液中吸收和荧光光谱的变化,计算得该剂基态和激发态分子的酸性常数（ｐＫａ＝８．８４,ｐＫａ＾＊＝５．１１）。基于在不同溶剂中荧光光谱的变化,由Ｓｏｌｖａｃｈｒｏｍｉｃ法,借助Ａｌｃｈｅｍｙ２０００量化计算软件,估算得该分子的基态和激发态偶极矩,分别为３．１１Ｄ和８．１３Ｄ。同时发现,ＭＭＣ－ＭＡＣ（Ｏ５）水溶液除氧后其荧光强度奇     

角分辨XPS对自组装单分子层厚度和官能团位置的定性及定量研究

用角分辨ＸＰＳ（Ａｎｇｌｅ－ｒｅｓｏｌｖｅｄＸＰＳ）研究研究了ＨＳ（ＣＨ２）１０ＣＯＯＨ（Ｉ）ＨＳ（ＣＨ２）３ＯＣ６Ｈ４Ｎ＝ＮＣ６Ｈ４（ＣＨ２）７ＣＨ３（ＩＩ）和ＨＳ（ＣＨ２）６ＨＳ（Ⅲ）３种分子在Ａｕ膜表面制备的自组装单分子层，得出了（Ｉ）中Ｓ原子，（Ⅱ）中Ｓ，Ｎ原子距膜表面的垂直距离，并结合构象分析确定了分子的取向和倾角，对分子（Ⅲ）则得出分子在紫外光照射下氧化反应的选择性，发现氧化主要在底层     

Br^—2,Cl^—2.诱导氧化磷酰化甲硫氨酸水溶液的脉冲辐解研究

采用脉冲辐解动态吸收光谱法研究了Ｂｒ＾－２和Ｃｌ＾－２自由在诱导氧化Ｎ－二异丙基磷酰化甲硫氨酸（ＮＤＭ）水溶液的过程，结果表明：Ｂｒ＾－２和Ｃｌ＾－２进攻ＮＤＭ中的硫原子形成含硫三电子键ＮＤＭ（Ｓ∴Ｘ）（Ｘ＝Ｂｒ，Ｃｌ）它们分别在４００ｎｍ和３９０ｎｍ处有最大吸收峰，形成和衰变均呈一级反应，测定了不同条件下氧化反应的速率常数，推导了反应机理，并从分子结构观点与甲硫氨酸水溶液的Ｂｒ＾－２．Ｃｌ＾－２     

Cu、Zn-SOD酶模型化合物催化O-2歧化作用的研究

本文采用ＮＢＴ法,利用７２１分光光度计,在ｐＨ＝７．８的条件下,测定了前文所合成的含Ｎ、Ｏ的Ｓ的Ｓｃｈｉｆｆ碱及其铜（Ⅱ）、锌（Ⅱ）配合物催化Ｏ２＾－歧化的活性,并探讨了平均抑制率与浓度的关系。     

共轭链长及羰基位置对分子二阶极化率的影响

采用引入外场微扰的ＣＮＤＯ／Ｓ－ＣＩ方法，计算一系列二苯基烯酮类化合物的分子二阶极化率（或二阶非线性光学指数）γβｖｃｃ值选取了苯环上含不同取代基团的化合物，从羰基在共轭链中的位置及共轭链长度方面，探讨了其微观二阶非线性光学效应的变化规律，结果表明，共轭链中羰基位置对βｖｃｃ值得重要的影响，并且呈现出一定的规律性，对于苯环上取代相同基团的化合物，其分子二阶非线性光学系数随共轭链长度的变化成指数关系     

SinSem分子簇的SCC—DV—Xa方法的计算研究

本文应用ＳＣＣ－ＤＶ－Ｘａ方法计算了（ＲＳｉ）４Ｓｅ６，（ＲＳｉ）２Ｓｅ３和Ｒ４Ｓｉ３Ｓｅ４（Ｒ＝ＣＨ３，Ｃ２Ｈ５，Ｐｈ）等分子簇的结合能，轨道能级，电荷分布，状态密度，分析了簇的稳定性，ＮＭＲ化学位移，紫外可见吸收和催化性能等，结果与实验相符。     

Temperature and concentration dependence of SANS spectra of aqueous solutions of short-chain amphiphiles

The small-angle neutron scattering (SANS) of some aqueous solutions of short-chain amphiphiles (glycols, diglycols, diols) has been measured as a function of concentration and temperature. The analysis of the spectra in terms of the Teubner-Strey phenomelogical formula indicates that, on increasing the concentration of the amphiphile, the structure of all these systems evolves in a similar way, i.e. a transition from disordered structures toward correlated aggregates (microstructures). The transition is depressed by increasing the temperature.     

荧光光谱研究含1,5取代萘刚性生色基双分子膜的相变

用荧光光谱研究了系列双亲物ＣｎＮａｐｈ（１,５）Ｃ６Ｎ＋（ｎ＝１６,１２,１０,８,６和４）聚集体的热致相变,发现荧光强度随温度升高发生了急剧变化,归因于聚集体从凝胶态到液晶态的相变。实验结果表明,尾链长短直接影响聚集体结构和相变温度Ｔｃ高低：尾链长,聚集体堆积密度大,荧光强度强,Ｔｃ高;反之亦反。荧光光谱的实验结果与透射电镜和ＤＳＣ研究结果一致。     

Micellization and phase separation in binary amphiphile mixtures

Grand canonical Monte Carlo simulations with histogram reweighting are used to examine the micellization and phase separation of a lattice model for binary amphiphile mixtures in an implicit solvent. The model amphiphiles consist of a neutral, rigid head group that occupies seven lattice sites and solvophobic tail chains of varying length and number. It is found that the critical micelle concentration of the mixtures closely matches theoretical values obtained by assuming that the components form an ideal mixture. The solubility of amphiphiles which undergo a first-order transition to form a disordered liquid phase can be increased by adding an amphiphile that forms micelles, and the phase transitions in these mixtures are between a dense liquid state and a low concentration phase that contains aggregates. In both micelles and dense liquids, the amphiphiles mix indiscriminately and the micelle size and shape depends on the concentration ratio of the two species.     

氯盐溶液近红外光谱分析研究

氯盐近红外光谱分析在生物医学上有着十分重要的意义。在室温下对氯化钠,氯化钾,氯化钙水溶液的近红外光谱采集分析表明,氯盐溶液浓度的变化会影响水分子的氢键而使得水溶液的近红外光谱发生变化。通过选择合理波长区间以及温度变化影响为零的波长点(等吸光点),减小温度的干扰对溶液近红外光谱影响,采用偏最小二乘法建立了氯盐溶液的浓度模型用于预测氯盐的离子浓度。分析氯盐溶液中氯盐阳离子的离子半径大小、离子电荷数和离子在水中络合效应等因素对水的近红外光谱所造成的影响以及产生影响因素的原因。实验结果表明,温度和浓度都会影响溶液的近红外光谱,氯盐溶液浓度较低时,温度的影响占主导地位;氯盐浓度高时,浓度的影响占主导地位。氯盐在水溶液中形成络合物,并与氯盐阳离子共同作用对水的氢键产生影响,对于浓度相同种类不同的氯盐溶液, 形成的络合物和阳离子破坏效应对水的氢键的破坏作用为: CaCl₂>NaCl>KCl。最终建立的样品浓度模型校正集的决定系数(R2)=99.97%,交叉验证均方误差(RMSECV)=4.51,剩余预测偏差(RPD)=62.7,满足日常生化检测精度要求。     

温度相关的微波频率下氯化钠水溶液介电特性

针对NaCl水溶液(0.001–0.5 mol/L)介电特性, 实验调查了频率(200–6.25 GHz), 温度(293–353 K)、 浓度相关复介电常数. 结果表明: 频率增大的过程中虚部呈逐渐减小的趋势, 高温使离子扰动增大, 破坏了溶液内部水分子四面体结构和氢键构象而使介电常数实部减小. 与纯水相比, 溶液的损耗角正切在高温353 K低频区下降明显. 同时发现2.45和5.8 GHz的复介电常数随温度变化的温度窗效应, 温度窗效应导致微波加热时耗散功率的振荡变化, 温度分布不均匀现象在实验中得以证实. 关键词： 微波 复介电常数 介电特性 高温探头     

水浴法制备ZnO纳米棒及其场发射性能

用硝酸锌(Zn(NO3)2·6H2O)与六亚甲基四胺(C6H12N4)以等浓度配制成反应溶液,通过水浴法制备出了形貌可控的棒状ZnO纳米结构,讨论了不同反应浓度及衬底对ZnO表面形貌的影响.样品的XRD和扫描电子显微镜分析结果表明,所得产物均为六方纤锌矿结构,在有晶种层的衬底上制备出的ZnO纳米棒沿(001)方向并垂直于衬底表面生长.随着反应浓度的增加,ZnO纳米棒的直径增大,长径比减小.样品的场发射性能测试表明,反应溶液浓度为0.005 mol/L,以铜膜为晶种层的硅衬底上制备出的场发射阴极具有较好的场发射性能.     

Aggregation and mesomorphic properties of ‘double-headed’ carbohydrate amphiphiles

Sugar-based amphiphiles, consisting of two sugar head groups and an alkylene chain within the molecules, are synthesized and their aggregation and mesomorphic properties are evaluated. The hydrophilic sugar head groups, constituted with β-D-glucopyranoside units, and the lyophilic alkylene units, are coupled to a glycerol backbone to afford the ‘double-headed’ sugar amphiphiles. Aggregation studies in aqueous solutions provided their critical micellar concentrations and the aggregation numbers. Mesophase characterizations by polarizing optical microscopy and differential scanning calorimetry (DSC) revealed the phase-transition behaviour of these new ‘double-headed’ glycolipids.     

Identification of micellar stability zones and structural inversion process of thermoresponsive polymeric micelles by dissipative particle dynamics simulations

The stimuli-sensitive polymeric micelles have huge applications to industrial and technological level, know their behaviour under the influence of a pure stimulus, such as the temperature is an important aspect to control and amplify its application field. In this paper, we investigate the micellar stability zones together with the structural inversion process of thermoresponsive polymeric micelles formed by a diblock copolymer (poly(N-isopropylacrylamide-b-3-[N-(3-methacrylamidopropyl)-N,N-dimethyl]ammoniopropane sulphonate (PNIPA-b-PSPP)) in an aqueous environment employing dissipative particle dynamics simulations. Our outcomes show that the PNIPA-b-PSPP copolymer has the ability to form thermodynamically stable micelles with different core-shell structure (PSPP-core/PNIPA-shell and PNIPA-core/PSPP-shell) depending on the direction of the applied stimulus (low or high temperature), the duality of this micellar behaviour is controlled by temperature effect and by the double hydrophilic character that exhibit the PNIPA and PSPP polymeric segments. Four micellar stability zones and one zone where only exist free unimer chains were detected during the thermal scan. The micellar inversion process is triggered by purely temperature effect, is totally reversible and involves three main stages: (1) micellar dissociation, (2) stabilisation of free unimer chains and (3) formation of inverse micelles, all transitory and metastable stages of micellar inversion process are described and analysed in this paper.     

Sonolysis of 4-chlorophenol in aqueous solution: effects of substrate concentration, aqueous temperature and ultrasonic frequency

The sonolysis of 4-chlorophenol (4-CP) in O2-saturated aqueous solutions is investigated for a variety of operating conditions with the loss of 4-CP from solution following pseudo-first-order reaction kinetics. Hydroquinone (HQ) and 4-chlorocatechol (4-CC) are the predominant intermediates which are degraded on extended ultrasonic irradiation. The final products are identified as Cl-, CO2, CO, and HCO2H. The rate of 4-CP degradation is dependent on the initial 4-CP concentration with an essentially linear increase in degradation rate at low initial 4-CP concentrations but with a plateauing in the rate increase observed at high reactant concentrations. The results obtained indicate that degradation takes place in the solution bulk at low reactant concentrations while at higher concentrations degradation occurs predominantly at the gas bubble-liquid interface. The aqueous temperature has a significant effect on the reaction rate. At low frequency (20 kHz) a lower liquid temperature favours the sonochemical degradation of 4-CP while at high frequency (500 kHz) the rate of 4-CP degradation is minimally perturbed with a slight optimum at around 40 degrees C. The rate of 4-CP degradation is frequency dependent with maximum rate of degradation occurring (of the frequencies studied) at 200 kHz.     

Magnetic and electrical transport properties of delta-doped amorphous Ge:Mn magnetic semiconductors

We report on the growth and characterization of delta-doped amorphous Ge:Mn diluted magnetic semiconductor thin films on GaAs (0 0 1) substrates. The fabricated samples exhibit different magnetic behaviors, depending on the Mn doping concentration. The Curie temperature was found to be dependent on both the Mn doping concentration and spacing between the doping layers. A sharp drop in magnetization and rise in resistivity are observed at low temperature in samples with high Mn doping concentrations, which is also accompanied by a negative thermal remanent magnetization (TRM) in the higher temperature range. The temperature at which the magnetization starts to drop and the negative TRM appears show a correlation with the Mn doping concentration. The experimental results are discussed based on the formation of ferromagnetic regions at high temperature and antiferromagnetic coupling between these regions at low temperature.