模糊数学理论在快速光度分析中的应用

根据分析化学内在的模糊性逻辑，建立了多元素快速光度测定的比耳定律及吸光度相加原理的数学模型，并以二苯硫腙-四氯化碳萃取光度法测定水中锌、镉、铅、银、汞、铊、钴、铜、铋及镍等多项重金属元素为例作试验证明。从试验结果可知，在数学处理中约束策略集的设定以及对分析数据（无论是光度法、AAS法或ICP-AES法的数据）的校正是十分重要的。     

An extension to rapid transit network design problem

The rapid transit network design problem consists of the location of train alignments and stations, in a context where the demand makes its own decisions about the mode and route. The originality of this study is to incorporate in the model the line locations constraints with a bounded but variable number of lines, and lines with no predetermined origins and destinations. The computational experiments show the necessity of this extension to solve large networks, principally because of its computational advantage. The project has been supported by Ministerio de Educación y Ciencia (Spain) under project TRA-2005-09068-C03-01/MODAL, and by Ministerio de Fomento (Spain) under project 2005/70029/T05.     

A temperature-jump stopped-flow system for monitoring chemical kinetics triggered by rapid cooling

This work reports the implementation of a stopped-flow system for studying the kinetics of protein folding triggered by rapid cooling. The transition from denaturing temperatures to ambient conditions is achieved by rapid mixing of pre-heated protein solution with cold refolding buffer. The estimated dead-time of the apparatus is 8 ms. Folding kinetics are monitored by fluorescence spectroscopy. Careful tuning of the solution mixing ratio is required for the elimination of baseline artifacts that could mask fluorescence signals originating from protein conformational changes. The viability of the rapid cooling method is demonstrated by applying it to monitor the refolding of thermally denatured cytochrome c. Following a heat exposure time of 3 min, the protein shows multi-exponential folding kinetics, ultimately resulting in a fluorescence level that is virtually indistinguishable from that of the native state. In contrast, incomplete refolding is observed when the heat exposure time is extended to 30 min. This effect may be due to aggregation phenomena affecting the thermally denatured protein. It appears that the rapid cooling approach reported in this work may become a useful tool for temperature-jump studies in various areas of chemistry and biochemistry.     

靶向性载体/基因复合物促进内皮细胞增殖

由于人工血管的表面缺乏活性内皮层,特别是小口径人工血管经常面临着长期通畅率低和再狭窄等难题,从而限制了其在临床上的应用。研究表明,通过基因复合物对内皮细胞转染可以在支架表面快速获得新生内皮层。近年来,基于靶向多肽修饰的基因载体为提高转染效率和降低载体毒性提供了有效的途径。本文详细介绍了目前用于基因转染的各种目的基因和基因载体,并以聚阳离子基因载体为基础,重点阐述了促进内皮细胞增殖的靶向性基因载体的研究进展,结合当前小口径人工血管研究进展,对采用基因转染方式实现其快速内皮化进行了分析和展望。     

胶体金核壳型沙丁胺醇分子印迹聚合物的光谱特征分析

为了解决饲料和动物产品中沙丁胺醇残留现场快速检测的难题,开发以分子印迹技术为基础的快速检测沙丁胺醇的新方法,使用沙丁胺醇做为模板分子,甲基丙烯酸(methacrylic acid, MA)作为功能单体,以本体聚合法为基础合成常规SAL分子印迹聚合物（molecularly imprinted polymer,MIPs）和非分子印迹聚合物（non imprinted polymer NIPs）。在此基础上,以胶体金粒子为引发核,制备出新型的核壳型沙丁胺醇MIPs。应用紫外吸收光谱(UV spectra)、傅里叶红外光谱(IR spectra)和拉曼光谱（Raman spectru）、扫描电镜（scanning electron microscopy,SEM）等技术手段获得两种印迹物及各种相关化合物的光谱图、电镜图等表征图像。由实验结果可知,SAL和MA上的羧基形成稳定又容易洗脱的1∶1型氢键配合物,化学结合常数K=-0.245×106 L2·mol-2。与MA的—COOH中氢原子形成氢键的可能结合位点是SALCO中的氧原子。MIPs与MA中—OH的吸收峰比较可知,前者明显红移; 证明SAL作为模板分子与MA之间发生特定结合。未洗脱MIPs的CO的伸缩振动产生的吸收峰红移; 即能量损失明显,可知MA中—COOH的氢原子如果要生成氢键,可能的结合位点就是SAL分子内CO中的氧原子。MIPs和NIPs中CC, CO, —OH等吸收明显的官能团峰型大致相同。将MIPs洗脱掉作为模板分子的SAL后,留下了含有特殊且确定结构官能团化学及空间构成均与SAL高度匹配的空穴, 可与待测液中的目标检测分子SAL发生特异性识别和专一结合作用。而胶体金核壳型MIPs与常规MIPs相比,除具有以上相同特点外,其表面更加松散,表面孔穴明显增多。由此增加了吸附目标分子的有效面积,具有更优良的吸附性能。这两种印迹物的合成及光谱特征分析为建立基于分子印迹技术的快速检测SAL新方法奠定了理论和实践基础。     

拉曼光谱在新型毒品快速检测中的应用

新型毒品的日益泛滥及快速更新对执法部门现场快速检测提出了越来越高的要求。以三种典型的新型毒品为例,利用密度泛函理论中的B3LYP杂化泛函,在6-31G基组下优化分子几何结构以及拉曼振动频率的计算,并利用拉曼光谱仪进行了实验检测,用以研究拉曼光谱技术在新型毒品快速检测中的应用价值。结果表明：各毒品样品的理论计算拉曼光谱与实验拉曼光谱基本吻合,理论计算光谱可以为实验光谱特征峰的归属提供参考;各毒品拉曼特征峰的峰位差异明显,其中冰毒特征峰为837和1003 cm-1,K粉最具有鉴别价值的特征峰为463,659和1 046 cm-1,而麻古最明显的特征峰为556,1 329和1 699 cm-1,拉曼光谱可被用于毒品的鉴别和认定;微量冰毒及K粉残留物的实验拉曼光谱与其常量时基本一致,拉曼光谱可被用于毒品微量残留物的准确识别;伪冰毒N-异丙基苄胺的拉曼特征峰853 cm-1与冰毒拉曼特征峰837 cm-1存在明显差异,因此拉曼光谱可被有效地用于以上毒品的检测;而聚丙烯材料制成的透明包装对自身存在强烈荧光干扰的麻古拉曼光谱有较大影响。     

Four-zone solidification microstructure formed by laser melting of copper thin films

Polycrystalline copper film microstructures produced by laser melting and rapid lateral solidification are analyzed using transmission electron microscopy. The microstructure is predominantly composed of directionally solidified grains up to 22 μm long and 1 μm wide lying in the plane of the film. We identify four morphologically solidification zones, corresponding to occlusion, steady lateral growth, defective growth, and nucleation. Electron diffraction analysis indicates clustering of 1 0 0 orientations around the direction of solidification for the grains in the steady lateral growth zone. Simple estimates of solidification times based on heat flow modeling and a critical nucleation temperature suggest that interface velocities of several hundred m/s may be attained during solidification.     

快压法制备非晶聚醚醚酮的应变诱导结晶行为

利用快速增压和淬火2种方法分别制备了非晶聚醚醚酮(PEEK), 并利用二维广角X射线衍射(WAXD)研究了2种非晶样品在不同拉伸温度(T_d)和不同应变速率(v)条件下的结晶行为. 结果表明, 在相同拉伸温度及应变速率条件下, 快压样品的临界结晶应变明显低于淬火样品; 随着拉伸温度和应变速率的升高, 2种样品的临界结晶应变均逐渐降低; 在相同应变条件下, 拉伸温度对PEEK材料结晶度的影响很大, 而应变速率对其影响较小.     

Preparation of 5-Hydroxymethylfurfural from Cellulose via Fast Depolymerization and Consecutively Catalytic Conversion

The conversion of cellulose to 5-hydroxymethylfurfural (HMF) has been investigated by a one-pot consecutive reaction. At first, cellulose was depolymerised into glucose via a fast degradation of cellulose in molten ZnCl2 in the presence of hydrochloric acid, and the yield of glucose is 75% in 120 s at reaction temperature of 95 oC. Then, DMSO was used as solvent and different kinds of metal chloride were added as catalysts, and the conversion was carried out continuously at 110-130 oC for 0.5-4 h. The yield of HMF was 53% when CrCl3 were used as catalyst. The one-pot two steps conversion was carried out at atmosphere pressure, and it is a simple route to prepare HMF from lignocellulosic feedstock on a large scale.     

高速远程地震黄土滑坡发生机制试验研究

研究了一种新的远程导弹飞行轨道的可行性,它的最大飞行高度约100km. 这种 超低弹道,借鉴卫星模式,利用离心力抵抗重力. 与卫星轨道运行不同的是,超低弹道周围 的稀薄空气影响至关重要,必须考虑. 计算和分析结果表明,在相同载荷条件和射程条件下, 超低弹道和经典的最小能量弹道对于火箭动力的需求大致相当,射程10000km以上基本相同. 头部半径为5cm的轴对称外形,沿超低弹道飞行时,其驻点热流在高度26km左 右达到最大值 50MW/m2, 约为最小能量弹道驻点热流最大值的50%. 由于超低弹道对升力没有要求, 飞行过程中的气动加热问题,沿用成熟方法如烧蚀防热即可解决. 总体而言,超低弹道对于 火箭动力与外形气动力/热要求,现有技术容易满足,因此利用它增强远程导弹的突防能力是 现实可能的.