InP单晶表面势垒高度与表面态密度的光伏测算

应用变温光伏方法测定了Ｎ型低阻ＩｎＰ单晶的表面势垒高度，进而分析、计算了简并化的ＩｎＰ单晶表面态密度。     

运用运动处方治疗大学生心理障碍的研究

随着科学技术的进步，社会竞争日益激烈，对大学生的冲击很大．近年来大学生中出现了许多不同程度的心理障碍，对大学生的健康成长起着很大的负面作用。本文通过实践和查阅各种资料等方法，发现运动处方对大学生的心理障碍具有良好的治疗效果，同时在制定运动处方时，我们要特别重视认知疗法的运用。     

混凝土开裂面剪力传递性质的理论与试验研究

为了能够用有限单元法分析钢筋混凝土结构,了解钢筋与混凝土的基本力学性质是十分重要的,混凝土开裂面的剪力传递性质就是其中之一。迄今为止国内尚未有人提供这方面的成果,国外的研究资料也不多,且都存在一定的局限性。本文从理论和试验两方面对混凝土开裂面的剪力传递性质进行了研究。     

对短跑“速度障碍”成因及其克服的研究

田径运动是各项运动的基础.而短跑又是田径运动的基础。短跑水平上不去,将影响到整个田径运动水平的提高。因此,提高短跑运动水平具有重要意义。在实际训练中,经常产生影响和阻碍短跑成绩提高的令教练员十分棘手的“速度障碍”。只有研究和分析“速度障碍”的成因,采取切实有效的方法和手段来克服速度障碍,才能保证短跑运动水平的提高。     

无转速检测电流源逆变交流电机驱动系统

文章介绍了一种无速度检测的感应电机电流源逆变驱动系统，以电动机定子上的电压和电流计算出转速估计值。系统是采用滑差频率的电流调节控制。     

PWM模拟信号光电耦合隔离电路的研制

本文提出一种运用PWM(脉冲调宽)原理设计低价格、低漂移、高线性模拟信号光电耦合隔离电路的方案。这种方案仅用普通的光电耦合器件。实验结果表明,这种隔离电路的非线性度不劣于0.02％,温度漂移低于0.002％/℃。本文还讨论了光电耦合器件的关断时间t_（OFF）对隔离电路动态范围的影响,并着重指出,关断时间温度系数（?）是影响隔离电路温度稳定性的主要因素。     

Lactate dehydrogenase and glutamate dehydrogenase activities in the circumventricular organs of rat brain following neonatal monosodium glutamate

Glutamate (glu) an excitatory neurotransmitter amino acid, is present in high concentrations in the mammalian central nervous system and is the most abundant amino acid in our daily diet. In the present study the activities of lactate dehydrogenase (LDH) and glutamate dehydrogenase (GDH) were evaluated in the circumventricular organs (CVO) of the brain in 25-day-old rats following MSG administration at a dose of 4 mg/g b.wt during the first ten days of life. The results show the LDH activity increased to 265% of that in the control (p<0.001), whereas GDH activity was significantly decreased (p<0.05), The great elevation in LDH, a cytoplasmic marker enzyme, is apparently due to cytoskeletal changes brought about as a consequence of glu toxicity, whereas lowered GDH activity indicates altered glu homostasis in the blood-brain-barrier deficient areas following neonatal exposure to glu.     

A relevant in vitro rat model for the evaluation of blood-brain barrier translocation of nanoparticles

Poly(MePEG₂₀₀₀cyanoacrylate-co-hexadecylcyanoacrylate) (PEG-PHDCA) nanoparticles have demonstrated their capacity to reach the rat central nervous system after intravenous injection. For insight into the transport of colloidal systems across the blood-brain barrier (BBB), we developed a relevant in vitro rat BBB model consisting of a coculture of rat brain endothelial cells (RBECs) and rat astrocytes. The RBECs used in our model displayed and retained structural characteristics of brain endothelial cells, such as expression of P-glycoprotein, occludin and ZO-1, and immunofluorescence studies showed the specific localization of occludin and ZO1. The high values of transendothelial electrical resistance and low permeability coefficients of marker molecules demonstrated the functionality of this model. The comparative passage of polyhexadecylcyanoacrylate and PEG-PHDCA nanoparticles through this model was investigated, showing a higher passage of PEGylated nanoparticles, presumably by endocytosis. This result was confirmed by confocal microscopy. Thanks to a good in vitro/in vivo correlation, this rat BBB model will help in understanding the mechanisms of nanoparticle translocation and in designing new types of colloidal carriers as brain delivery systems.Received 4 March 2005; accepted 14 April 2005     

Decision-making at the surface of the intact or barrier disrupted skin: potential applications for vaccination or therapy

The skin is a highly accessible organ and constitutes an active immunological site. Both these properties make this surface an attractive route for what promises to be a cost-effective, simple, practical and needle-free delivery of vaccines and immunomodulators. Less obvious is the fact that the state of the skin barrier can influence quantitative and qualitative aspects of antigen-specific immune responses. The everyday decision-making at the skin epithelium concerns the choice between the induction of an immune response and the establishment of a state of non-responsiveness (tolerance). This decision is influenced by various factors such as the dose, the route (intact vs barrier-disrupted skin), the cytokine microenvironment and the nature of the antigenic stimulus. By increasing our understanding of how immune responses are regulated in the epidermis we can envisage the development of immunisation protocols aimed at eliciting a protective immune response or inducing tolerance, with direct applications to preventive or therapeutic vaccination, respectively.Received 29 November 2004; received after revision 2 February 2005; accepted 22 February 2005     

磁场调制下单层石墨烯势垒结构的隧穿特性

利用传递矩阵方法,在多方势垒基础上,采用渐近手段,研究了单层石墨烯不同势垒结构(方势垒和劈形势垒)的隧穿特性,结果发现势垒形状影响隧穿特性.对于2种形状的势垒结构,无论是透射系数还是平均电导率,既展现出相同的特点,又有明显不同之处.通过比较透射系数与平均电导率,得出各自的特点,为实际设计纳米器件提供理论基础.