应用玻璃微米/纳米管和循环伏安法研究邻菲咯啉加速质子在水/1,2-二氯乙烷界面的转移过程

利用循环伏安法研究了玻璃微米 /纳米管支持的水 / 1 ,2 -二氯乙烷 ( DCE)界面上邻菲咯啉加速质子的转移过程 .将装有水溶液的微米 /纳米管插入到 DCE溶液中 ,可以形成微米 /纳米级 -液 /液界面 ,在选定的实验条件下 ,其作用类似于微米 /纳米电极 .用微米管考察了此加速转移过程的半波电位与 p H值 ( 1 .1～7.5 )的关系 ,利用 Matsuda等提出的理论公式计算了邻菲咯啉与质子在有机相和水相中的络合常数比 .并用纳米管计算得到邻菲咯啉加速质子在水 / DCE界面转移过程中的标准速率常数 ( k0 )和转移系数 (α)分别为( 0 .1 83± 0 .0 5 4 ) cm/ s和 0 .70± 0 .0

Phase identification in a series of liquid crystalline TPP polyethers and copolyethers having highly ordered mesophase structures. 7. Phase structures in a series of copolyethers containing odd and even numbers of methylene units of different compositions

A series of liquid crystalline copolyethers have been synthesized from 1-(4-hydroxy-4'-biphenyl)-2-(4-hydroxyphenyl)propane with 1,7-dibromoheptane and 1,12-dibromododecene [coTPPs(7/12)], which represents copolyethers containing both odd and even numbers of methylene units. The molar ratio of odd to even methylene units in this series ranges from 1/9 to 9/1. The coTPPs(7/12) exhibit multiple phase transitions during cooling and heating in differential scanning calorimetry experiments. For all these thermal transitions, a small undercooling and superheating dependence is observed upon cooling and heating at different rates. Three types of phase behaviors can be classified in coTPPs(7/12) on the basis of the structural analyses by wide-angle X-ray diffraction on powder and fiber samples and by electron diffraction experiments in transmission electron microscopy. At room temperature, highly ordered smectic and smectic crystal (SC) phases are identified in coTPPs(7/12: 1/9 and 2/8), which is similar to the homopolymer TPP(m = 12). The coTPPs(7/12: 3/7, 4/6, and 5/5) possess a hexagonal columnar (Phi(H)) phase in which the molecular and columnar axes are parallel to the fiber direction and perpendicular to the hexagonal lateral packing. The coTPPs(7/12: 6/4, 7/3, and 8/2) possess a tilted hexagonal columnar (Phi(TH)) phase with a single tilt angle which increases with the increasing composition of the seven-numbered methylene units. However, in coTPP(7/12: 9/1), a Phi(TH) phase with multiple tilt angles is found. Upon heating, phase structures in most coTPPs(7/12) involving the columnar phases enter directly into the nematic (N) phase, while the coTPP(7/12: 1/9) exhibits a highly ordered smectic F (S-F) phase before it reaches the N phase. One exception is found in coTPP(7/12: 2/8), wherein the transformation from the S-F to Phi(H) occurs prior to the N phase. Combining the copolymer phase behaviors observed with the corresponding homopolymers TPP(n = 7) and TPP(m = 12), a phase diagram describing transition temperatures with respect to the composition can be constructed.

Gas separation properties of aromatic polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 3,5-diaminobenzic acid or its esters

The gas transport properties of a series polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with 1,3-phenylenediamine or 3,5-diaminobenzic acid (DBA) or its esters are reported. The effects of carboxylic group (-COOH) and carboxylic ether groups (-COOR), at five positions of 1,3-phenylenediamine moiety, on H-2, CO2, O-2, and N-2 permeability, diffusivity, and solubility of the polyetherimides were investigated. The gas permeability, diffusion, and solubility coefficients of the polyetherimides containing COOR are bigger than those of HQDPA-PDA, but the ideal separation factors and ideal diffusivity selectivity factors are much smaller than that of HQDPA-PDA because COOR decreases chain segmental packing efficiency and increases chain segmental mobility. The permeability coefficients of HQDPA-DBA to H-2, CO2, and O-2 are bigger than those of HQDPA-PDA; the ideal separation factors for gas pairs H-2/N-2, CO2/N-2, and O-2/N-2 are also much bigger than those of HQDPA-PDA. Both the diffusion coefficients of CO2 and O-2 and the ideal diffusivity selectivity factors for CO2/N-2 and O-2/N-2 are bigger than those of HQDPA-PDA because COOH decreases both chain segmental packing efficiency and chain segmental mobility. The copolyimides, which were prepared from 3,5-diaminobenzic acid and 3,5-diaminobenzic esters, have both high permeability and high permselectivity. (C) 1997 John Wiley & Sons, Inc.

Molecular cloning and stress-dependent expression of a gene encoding Delta(12)-fatty acid desaturase in the Antarctic microalga Chlorella vulgaris NJ-7

The psychrotrophic Antarctic alga, Chlorella vulgaris NJ-7, grows under an extreme environment of low temperature and high salinity. In an effort to better understand the correlation between fatty acid metabolism and acclimation to Antarctic environment, we analyzed its fatty acid compositions. An extremely high amount of Delta(12) unsaturated fatty acids was identified which prompted us to speculate about the involvement of Delta(12) fatty acid desaturase in the process of acclimation. A full-length cDNA sequence, designated CvFAD2, was isolated from C. vulgaris NJ-7 via reverse transcription polymerase chain reaction (RT-PCR) and RACE methods. Sequence alignment and phylogenetic analysis showed that the gene was homologous to known microsomal Delta(12)-FADs with the conserved histidine motifs. Heterologous expression in yeast was used to confirm the regioselectivity and the function of CvFAD2. Linoleic acid (18:2), normally not present in wild-type yeast cells, was detected in transformants of CvFAD2. The induction of CvFAD2 at an mRNA level under cold stress and high salinity is detected by real-time PCR. The results showed that both temperature and salinity motivated the upregulation of CvFAD2 expression. The accumulation of CvFAD2 increased 2.2-fold at 15A degrees C and 3.9-fold at 4A degrees C compared to the alga at 25A degrees C. Meanwhile a 1.7- and 8.5-fold increase at 3 and 6% NaCl was detected. These data suggest that CvFAD2 is the enzyme responsible for the Delta(12) fatty acids desaturation involved in the adaption to cold and high salinity for Antarctic C. vugaris NJ-7.

7-11岁正常儿童和ADHD儿童故事重述能力及策略的发展

儿童的故事重述涉及工作记忆和抽象表征能力，是与儿童的日常学业任务密切联系。儿童能否把握时间线索来组织故事重述，反映的是儿童抽象出故事事件内在时间关系的能力，因此对儿童故事重述的探查可以揭示儿童抽象思维发展的一般规律和特点。本研究在前人研究的基础上，系统探查了7－11岁儿童故事重述能力及其策略的发展过程，探讨了时间线索对儿童故事重述的影响，并对ADHD儿童和正常儿童的故事重述及策略进行了比较。 主要研究结果如下： (1)7－11岁儿童故事重述能力总体上随年龄增长而提高，按正确顺序重述的事件数量增多，重述过程中提取和使用的时间线索也增加。其中7－9岁有较快速的发展。 (2)随故事中包含的事件数量的增加，故事难度增大，儿童的故事重述成绩有所下降，故事长度对7岁和9岁儿童的影响大于对11岁儿童的影响。 (3)有、无时间线索语词会影响儿童的故事重述。故事中包含时间语词线索有助于儿童的故事重述。11岁儿童的故事重述已不受有、无时间线索的影响，他们在无时间线索的条件下，更多地主动使用表示因果关系的语词来表征事件关系。 (4)ADHD儿童的故事重述能力在9岁到11岁有较快的发展。但总体而言，ADHD儿童对含有时间线索故事的重述能力显著差于正常儿童。 (5)故事再学习对ADHD儿童和正常儿童的故事重述都存在促进作用。但ADHD儿童故事再学习效果不如正常儿童，低龄儿童中差距尤其明显，随着年龄的增加，ADHD儿童与正常儿童故事再学习效果的差距逐渐缩小。 (6)不同年龄的儿童主要采用四种策略解决问题。随年龄增长，正常儿童和ADHD儿童中使用水平较高的内容主线和逻辑关系策略的人数都有所增加。但ADHD儿童中高水平策略使用人数比例仍低于正常儿童。

Fractal Pattern Formation In Anodic Bonding Of Pyrex Glass/Al/Si

Anodic bonding of Pyrex glass/Al/Si is an important bonding technique in micro/nanoelectromechanical systems (MEMS/NEMS) industry. The anodic bonding of Pyrex 7740 glass/Aluminum film/Silicon is completed at the temperature from 300 degrees C to 375 degrees C with a bonding voltage between 150 V and 450 V. The fractal patterns are formed in the intermediate Al thin film. This pattern has the fractal dimension of the typical two-dimensional diffusion-limited aggregation (2D DLA) process, and the fractal dimension is around 1.7. The fractal patterns consist of Al and Si crystalline grains, and their occurrences are due to the limited diffusion, aggregation, and crystallization of Si and Al atoms in the intermediate Al layers. The formation of the fractal pattern is helpful to enhance the bonding strength between the Pyrex 7740 glass and the aluminum thin film coated on the crystal silicon substrates.

直墙前破波波浪力──对修正过的Gota方法的探讨

对被重新修正后的Goat在墙波压力计算方法进行了分析，主要是对其无因次波浪力随基床肩宽和相对波高的变化进行分析，结果发现，Goat法计算的无因次波浪力随基床肩宽的变化，有一最不利肩宽，此不利肩宽与相对波高无关；在同一水深条件下，Goat法计算的无因次波浪力随相对波高的增大而增大。此两点与试验数据不符。

The size-dependent bending elastic properties of nanobeams with surface effects

A theoretical model is presented to investigate the size-dependent bending elastic properties of a nanobeam with the influence of the surface relaxation and the surface tension taken into consideration. The surface layer and its thickness of a nanostructure are defined unambiguously. A three-dimensional (3D) crystal model for a nanofilm with n layers of relaxed atoms is investigated. The four nonzero elastic constants of the nanofilm are derived, and then the Young's modulus for simple tension is obtained. Using the relation of energy equilibrium, the size-dependent effective elastic modulus and effective flexural rigidity of a nanobeam with two kinds of cross sections are derived, and their dependence on the surface relaxation and the surface tension is analysed.

关于复合材料力学几个基本问题的研究

凡能进行两层次分析与计算的材料便可称为复合材料，复合材料力学则是一种两层次的力学理论。相（材料）通过复合（效应、工艺）形成复合材料。复合效应分为混合效应和协同效应，其相应的混合律和协同律是复合材料力学理论的奠基石。前者已形成理论体系，后者有待形成。本文所论及的随机扩大临界核理论可解释多种形式的协同效应。此外，本文还讨论了几个有关的力学问题。

水网区域的水质模拟预报及污染容量

本文研究了頔塘河震泽段的水质指标(BOD、DO)在水体中的迁移转化规律,建立起模拟頔塘河震泽段的水持数学模型。在以水环境规划为目标的水质数值模拟中,首次结合全面的水文分析及该河段的模型参数估计,给出頔塘河震泽段的水质模拟预报及全年污染容量的计算,作为水质管理规划的定量依据。

圆柱壳孔边裂纹应力强度因子的计算和分析

从Reissner壳体理论出发,将“局部-整体分析法”应用于圆柱壳孔边裂纹问题,比较精确地计算了圆柱壳孔边轴向裂纹和环向裂纹的应力强度因子,获得了应力强度因子随壳体几何尺寸、开孔大小及剪切刚度变化的规律。以作者在文[7,8]中的有限元分析结果为基础,推广Petroski-Achenbach方法,建立圆柱壳孔边裂纹问题的权函数,分析计算了圆柱壳孔边裂纹问题,获得了较好的结果,最后给出了便于工程应用的较精确的计算鼓胀系数的近似公式。

正常固结饱和粘土的孔隙水压力

本文认为土体的剪胀性是偏应力的二次幂效应。根据这个假设,提出了孔隙水压力的计算公式。对正常固结饱和粘土的三轴不排水压缩试验结果进行了分析。分析结果表明,新的孔隙水压力公式合理地反映了正常固结饱和粘土的剪胀性。本文对土体的破坏问题也作了简要讨论。

一种聚变反应堆装置的新概念

本文提出了一个聚变反应堆装置的新概念,它由两个轴对称的类似串联磁镜的部分和两个螺旋仿星器U形弯曲段组成,并综合了直管和环形、快过程和慢过程的优点。文中研究了起动、过渡和运行阶段,讨论了D-D反应堆参数和稳定性。射频和高能分量只在起动阶段才需要,在整个过程中只有瞬时的能量消耗。端塞也只须在起动阶段存在,这大大降低了工程技术要求。