Development of a propulsion system for a biomimetic thruster

We studied theoretically and experimentally a biomimetic propulsion system inspired by the motility mechanisms of bacteria such as E. coli. Our goal was to investigate the effect of the "complex" filament of Rhizobium Meliloti bacteria on thrust force. The complex filament is a helically perturbed filament,similar to a plain filament threaded through a small helix. The propulsive performance of this system was estimated by modeling the dynamics of helical wave motion in viscous fluid. The model consists of a helical filament which is axially rotated at angular velocity ω. Resistive force theory(RFT) was applied to this model to calculate the thrust force and required torque. The Buckingham PI theorem(non-dimensional analysis) was also used to analyze the theoretical results. The procedure for making a complex filament with various pitch angles θs from a small helix and plain filament is explained in detail. To validate the theoretical results for helical wave propulsion and compare the characteristics of complex and plain filaments together,an experiment was performed to measure the thrust forces in silicone oil. The experimental results agreed with the theoretical values predicted by RFT. The thrust forces of complex filaments depended on the shape of small helix winding. The maximum thrust force was achieved at a small helix pitch angle of θs = 45°. In addition,we found that the thrust force generated by a complex filament had a value about 10% higher than that of a plain filament with the same equivalent diameter de.     

基于模糊综合评判的作战指挥辅助决策系统效能评估

针对部队作战指挥辅助决策系统效能评估问题,提出了评估的指标体系,采用现代系统评估理论的层次分析法确定了评价指标的权重,建立了模糊综合评判模型,并通过对具体的实例的计算分析,验证了该模型的有效性。     

SPIN90 dephosphorylation is required for cofilin-mediated actin depolymerization in NMDA-stimulated hippocampal neurons

Actin plays a fundamental role in the regulation of spine morphology (both shrinkage and enlargement) upon synaptic activation. In particular, actin depolymerization is crucial for the spine shrinkage in NMDAR-mediated synaptic depression. Here, we define the role of SPIN90 phosphorylation/dephosphorylation in regulating actin depolymerization via modulation of cofilin activity. When neurons were treated with NMDA, SPIN90 was dephosphorylated by STEP61 (striatal-enriched protein tyrosine phosphatase) and translocated from the spines to the dendritic shafts. In addition, phosphorylated SPIN90 bound cofilin and then inhibited cofilin activity, suggesting that SPIN90 dephosphorylation is a prerequisite step for releasing cofilin so that cofilin can adequately sever actin filaments into monomeric form. We found that SPIN90 YE, a phosphomimetic mutant, remained in the spines after NMDAR activation where it bound cofilin, thereby effectively preventing actin depolymerization. This led to inhibition of the activity-dependent redistribution of cortactin and drebrin A, as well as of the morphological changes in the spines that underlie synaptic plasticity. These findings indicate that NMDA-induced SPIN90 dephosphorylation and translocation initiates cofilin-mediated actin dynamics and spine shrinkage within dendritic spines, thereby modulating synaptic activity.     

有机发光二极管的最新发展

本文介绍了有机发光二极管的构造与发光机理，并结合我们自己的工作展望了有机发光二极管的发展趋势。     

Therapeutic induction of angiogenesis by direct myocardial administration of an adenovirus vector encoding human hepatocyte growth factor gene and its safety

After the study in vitro and in rats, we assessed further the effects and safety of local angiogen therapy using intramyocardial delivery of an adenovirus carrying hepatocyte growth factor gene (Ad-HGF) in a canine ischemia model. The angiogenic activity of Ad-HGF was evaluated from three aspects. First, the augmentation of collateral vessel development was assessed by angiography 30 d after surgery. The results showed that the density of collateral vessels in treated group was higher than that of control group. Secondly, infarct size was evaluated by TTC staining and image analysis. The results showed that the infarct size of treated group was smaller than that of control group. Thirdly, the myocardial regional blood flow was determined by the method of colored microspheres. The results showed that the blood flow recovered to the level before ligation in treated group, but that of the control group was lower than normal level. In addition, during the study of chronic toxicity, we tested the anti-adenovirus antibodies by neutralization method. The antibodies yielded after the fourth injection decreased slowly from peak level and disappeared 12 weeks after drug withdrawal. Overall, Ad-HGF can promote angiogenesis in ischemic myocardium and reduce infarct size. So this method may be considered as a therapeutic angiogenesis induction strategy for ischemic disease including myocardial infarction and peripheral artery disease. At the same time, Ad-HGF could induce the yield of anti-adenovirus antibodies to neutralize adenovirus, which may be the mechanism of adenovirus clearance.     

基于预映射动态选择S盒的Hash函数

在分析已有WHF函数的基础上,通过对AES算法中30个既约多项式对应S盒的实现及性质讨论,提出了一种基于预映射动态选择S盒的hash函数。经过理论分析和实验证明,新算法在安全性和效率上均得到了进一步的提高。     

试论高师体育系教学改革与学生基本能力培养

本文从师范院校培养目标和体育教师的职业特点出发,着重从体育专业技术课教学中探讨体育系学生基本能力培养问题.     

电致发光粉ZnS:Cu的透明防潮包覆

在现有包覆方法基础上进行了改进且得到了满意的包覆效果.以有机硅、铝为反应物用Sol-Gel法,在微米尺度的电致发光粉表面上形成一层厚度均匀的纳米薄膜,实现了电致发光粉ZnS:Cu的透明防潮包覆.实验结果表明:包覆3次的薄膜最均匀且致密,抗变色时间大于120min;包覆后的电致发光粉ZnS:Cu可以保持未包覆时发光强度的93%以上,且包覆次数对发光强度的影响很小;温度低于200℃时其抗腐蚀性能良好,用透射电子显微镜(TEM)和X射线荧光探针光谱分析仪(EDXS)对包覆膜进行了表征.经过包覆后的电致发光粉表面的铝和硅含量在不断增加且硅增加的速度快于铝增加的速度.