Molecular dynamics study of structural evolution of aluminum during rapid quenching under different pressures

We present a molecular dynamics simulation for liquid Al during the rapid quenching under different pressures. The pair analysis technique and the probabilities of bond energy distribution of inherent structures have been employed to reveal the structural characteristics of liquid and glassy Al. During the liquid-glass quenching process, the bond pairs representing the degree of icosahedral short-range ordering are largely enhanced, whereas the bond pairs being related to fcc and hcp crystalline order increase at first then decrease. The pressure effect on various bond pairs for liquids is larger than for glasses. Two kinds of bond pairs, which exist in large proportion in the amorphous, are demonstrated for the transformation from 1431 to 1541 bond pairs when decreasing temperature or increasing pressure below glass transformation temperature (T_g). Although the sum of these two pairs keeps unchanged below T_g, the role of them is like a bridge which links another two different kinds of bonded pairs, icosahedral ordering and crystalline ordering pairs.     

车辆电子电气系统测试方法研究

随着车辆电子信息技术的飞速发展,车辆电子电气系统在整车的可靠性中起着至关重要的作用。对电子电气系统的测试传统的做法往往是在整个系统完成之后利用整车环境进行的,这种方法不利于发现早期问题,对系统可靠性带来隐患;为了提升车辆电子电气系统可靠性,主要从实际工程测试出发,从项目的前期以及后期两个方面对电子电气系统的测试进行了分析,在项目的前期主要进行快速原型以及HIL测试,在项目的后期主要进行功能、性能、接口测试,从而实现提升车辆电子电气系统高可靠性以及经济性的提升。     

A European perspective on progress in moving away from the mouse bioassay for marine-toxin analysis

This review considers the ethical and technical problems currently associated with employing mouse bioassays for marine-toxin analysis and the challenges and the difficulties that alternative methods must overcome before being deemed applicable for implementation into a regulatory monitoring regime. We discuss proposed alternative methods, classified as functional, immunological and analytical, for well-established European toxins as well as emerging toxins in European waters, highlighting their advantages and disadvantages. We also consider emerging tools and technologies for future toxin analysis.Even though regulatory bodies have recently recommended analytical methods for a number of toxins, there is still scope for functional and immunological methods in rapid screening and detecting emerging toxins. Future developments foreseen in the analysis of marine biotoxins are multiplex-based analysis, miniaturization and portability for on-site testing. However, the longstanding lack of reference materials and standards continues to pose a severe limitation on progress in development, validation and therefore implementation of any alternative method based on the criteria stipulated by European Union legislation.     

Implications of partial tryptic digestion in organic-aqueous solvent systems for bottom-up proteome analysis

For bottom-up MS, the digestion step is critical and is typically performed with trypsin. Solvent-assisted digestion in 80% acetonitrile has previously been shown to improve protein sequence coverage at shorter digestion times. This has been attributed to enhanced enzyme digestion efficiency in this solvent. However, our results demonstrate that tryptic digestion in 80% acetonitrile is less efficient than that of conventional (aqueous) digestion. This is a consequence of decreased enzyme activity beyond ∼40% acetonitrile, increased enzyme autolysis and lower protein solubility in 80% acetonitrile. We observe multiple missed cleavages and reduced concentration of fully cleaved digestion products. Nonetheless we confirm, through room temperature solvent-assisted digestion, a consistent improvement in protein sequence coverage when analyzed by mass spectrometry. These results are explained through the increased number of unique digestion products available for detection. Thus, while solvent-assisted digestion has clear merits for proteome analysis, one should be aware of the inefficiency of protein digestion though this protocol, particularly with absolute protein quantitation experiments.     

基于激光诱导水拉曼抑制法的油膜厚度测量方法研究

为了实现水体表面油膜厚度的快速测量分析,以266 nm的激光作为探测系统的激发光源,基于激光诱导水拉曼散射光谱检测技术,通过获取不同种类不同厚度油膜存在下水拉曼光谱信息,建立油膜厚度反演模型。采用高斯函数拟合法校正了荧光光谱对拉曼光谱的干扰。然后根据水拉曼抑制法结合非线性最小二乘优化算法,建立油膜厚度反演模型。结果表明：对92#汽油、0#柴油、美孚机油20w-40、壳牌润滑油10w-40、采埃孚变速箱油AG6和原油油膜能探测到的油膜厚度范围为0.19~379.22 μm。采用水拉曼光谱-油膜厚度反演模型预测油膜厚度的平均相对误差在8.14%~15.81%之间。该方法能实现实验室条件下对微米级油膜的测量。     

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。     

Preparation of HNS microspheres by rapid membrane emulsification

In order to improve the dispersibility and loading efficiency of 2,2′,4,4′,6,6′-hexanitrostilbene (HNS), HNS microspheres were prepared by rapid membrane emulsification method with nitrocellulose (NC) as binder. The effects of NC solution concentration, stirring speed and polyvinyl alcohol (PVA) solution concentration on microspheres were investigated. It was characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), differential thermal analysis (DTA) and angle of repose analyzer. The results show that the HNS microspheres prepared with 5 wt% NC solution concentration, stirring speed of 100 rpm and 2 wt% PVA solution concentration have better regular morphology, higher sphericity, unchanged crystalline shape, increased activation energy and significantly improved dispersibility compared with the refined HNS. Rapid membrane emulsification has a series of advantages such as green, low cost and easy scale up, which provides a better way to prepare microspheres of energy materials.     

Highly Efficient Production of Nanoporous Block Copolymers with Arbitrary Structural Characteristics for Advanced Membranes

The great significance of boosting the design of percolating nanopore structures in block copolymers (BCPs) for various cases has been widely demonstrated in the past several decades. However, it still remains challenging to prepare the desired porous structures in a rapid, facile, and universal manner. Here we have developed an unconventional and benchtop strategy to rapidly generate the nanoporous polystyrene-based BCPs with arbitrary structural characteristics regardless of the BCP bulk morphology. This universal pore-forming strategy enables the sustainable CO₂-based BCPs to form advanced membranes after 1 s soaking for efficiently rejecting 94.2 % brilliant blue R (826 g mol⁻¹). Meanwhile, the water permeance retains around 1020 L (m² h bar)⁻¹, which is 1–3 orders of magnitude higher than that of other membranes. This strategy may offer an excellent opportunity to introduce percolating pore structures in those newly developed BCPs with which the previously reported pore-forming methods may not deal.