Platinum nanoparticles supported on activated carbon fiber as catalyst for methanol oxidation

Activated carbon fiber (ACF) with high specific surface area has been used as support in the preparation of Pt nanoparticles electrocatalyst (Pt/ACF) for direct alcohol fuel cells. It is found that the Pt nanoparticles on ACF are highly and homogeneously dispersed with a narrow size distribution in the range of 1.5–3.5 nm with an average size of 2.4 nm. In comparison with the commercial E-TEK Pt/C catalyst, the Pt/ACF catalyst exhibits much higher catalytic activity for methanol, ethanol and isopropanol oxidation, which are about 2.4 times as high as that of the former. The Pt/ACF catalyst is observed to be significantly more stable during the constant current density polarization and continuous cyclic voltammetry in comparison with Pt/C catalyst. Both the uniform dispersion of Pt nanoparticles and strong interactions between Pt nanoparticles and ACF are of benefit to achieve the performance improvement of Pt/ACF catalyst.     

油田集输站自动控制系统硬件设计

本文介绍了计算机在油田集输站中的应用，给出了自动控制系统硬件设计，系统具有稳定、可靠等特点。     

结合进化规划的图像分水岭分割技术

为了解决分水岭算法的过分割问题,提出用一种结合进化规划的控制标记符提取技术对图像进行预处理的分水岭图像分割方法。该方法基于进化规划的生灭过程,对传统分水岭分割中的图像目标区域进行重新标记,根据新标记的区域特点,重新设置图像目标区域的控制标记符。然后通过分水岭变换,实现图像的区域分割。实验结果表明,该方法既能有效解决分水岭算法的过分割问题,又保留了各种重要的目标区域,可以得到较满意的图像分割结果。     

上海光源X射线成像实验站相位衬度CT初步结果

X射线相位衬度CT能获得样品内部结构的边缘增强图像,可观察到传统X射线吸收CT无法观察到的生物软组织内部微细结构,具有巨大发展潜力.经初步调试,上海光源X射线成像实验站的8-72.5 keV单色X射线输出已能用于实验研究.本文在X射线成像实验站上开展生物样品(蝗虫)同轴X射线相位衬度CT研究,获得蝗虫样品的切片重构图像和三维重建图像.结果图像中,蝗虫样品的翅膀、表面纹理和内部组织分布情况清晰可见.     

Blocking ERK-DAPK1 Axis Attenuates Glutamate Excitotoxicity in Epilepsy

Glutamate excitotoxicity induces neuronal cell death during epileptic seizures. Death-associated protein kinase 1 (DAPK1) expression is highly increased in the brains of epilepsy patients; however, the underlying mechanisms by which DAPK1 influences neuronal injury and its therapeutic effect on glutamate excitotoxicity have not been determined. We assessed multiple electroencephalograms and seizure grades and performed biochemical and cell death analyses with cellular and animal models. We applied small molecules and peptides and knocked out and mutated genes to evaluate the therapeutic efficacy of kainic acid (KA), an analog of glutamate-induced neuronal damage. KA administration increased DAPK1 activity by promoting its phosphorylation by activated extracellular signal-regulated kinase (ERK). DAPK1 activation increased seizure severity and neuronal cell death in mice. Selective ERK antagonist treatment, DAPK1 gene ablation, and uncoupling of DAPK1 and ERK peptides led to potent anti-seizure and anti-apoptotic effects in vitro and in vivo. Moreover, a DAPK1 phosphorylation-deficient mutant alleviated glutamate-induced neuronal apoptosis. These results provide novel insight into the pathogenesis of epilepsy and indicate that targeting DAPK1 may be a potential therapeutic strategy for treating epilepsy.     

Application of program generation technology in solving heat and flow problems

Based on a new DIY concept for software development,an automatic program-generating technology attached ona software system called as Finite Element Program Generator(FEPG)provides a platform of developing pro-grams,through which a scientific researcher can submit his special physico-mathematical problem to the systemin a more direct and convenient way for solution.For solving flow and heat problems by using finite elementmethod,the stabilization technologies and fraction-step methods are adopted to overcome the numerical difficul-ties caused mainly due to the dominated convection.A couple of benchmark problems are given in this paper asexamples to illustrate the usage and the superiority of the automatic program generation technique,including theflow in a lid-driven cavity,the starting flow in a circular pipe,the natural convection in a square cavity,and theflow past a circular cylinder,etc.They are also shown as the verification of the algorithms.     

喜树碱生物合成途径及其代谢调控的研究进展

喜树碱类抗癌药物的大量生产是目前生物技术研究的热点之一。本文通过对喜树碱的生物合成途径和关键酶及其基因的表达调控等方面的研宽进展进行综述,指出阐明喜树碱的生物合成途径及其代谢调控机制,实施次生代谢工程,是应用生物技求方法大量生产喜树碱及其衍生物的根本途径。     

Unsaturated Water Transport of Cement-based Materials

The slice-weighing method was used to investigate the unsaturated water transport of different cement pastes. The experimental results show that a sharp wetting front existed during water transport, the transport can be described by a non-linear diffusion equation, and transport coefficient of different materials exhibit various rules with water content of materials. The addition of fly-ash decreases transport coefficient of cement pastes in all the various water contents, even changes the transport mechanism.     

大件热处理的温度场、显微组织及性能预测

本文运用传热学和相组织转变的基本原理,对轴类、筒体大件热处理的加热、冷却温度场和组织、性能预测进行了研究并编制了相应的计算程序。考虑了相变潜热对温度场的影响,将温度场与组织转变这两个相互影响的过程作为一个整体同时进行观测,并考虑了温度对导热系数、比热和密度等物理参数的影响以及晶粒大小对组织转变的影响。