相关腐蚀与疲劳及维修对船体可靠性的影响

将腐蚀和疲劳作为非正态相关变量来处理，真实合理地反映了疲劳腐蚀间紧密的内部关联．采用渐进崩溃法计算船体总纵极限强度，将响应面法与传统可靠性计算方法相结合来进行船体总纵极限强度可靠性分析．利用Nataf转化原理获得随机变量当量正态化后新的相关因子．船舶维修对于可靠性的影响通过三种维修决策来实现：无修理，少量修理，更新．对一艘万吨散货船应用该方法进行了分析计算．通过与常规线性叠加方法比较表明，采用相关原理处理疲劳腐蚀间的相互作用是一个合理、有效且实用的方法．     

Catalytic Combustion of Lean Methane Assisted by Electric Field over Pd/Co<Subscript>3</Subscript>O<Subscript>4</Subscript> Catalysts at Low Temperature

A series of Pd/Co₃O₄ catalysts were prepared by Self-Propagating High-Temperature Synthesis (SHS) method in this study, and electric field was applied for catalytic combustion of lean methane over Pd/Co₃O₄ catalysts at low temperature. When electric field was applied, the catalytic combustion performance of Pd/Co₃O₄ catalysts was greatly improved, and the application of electric field could reduce the load of active element Pd to some extent while maintaining the same efficiency. Based on experimental tests and the analysis results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H₂-temperature-programmed reduction (H₂-TPR) and in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS), the mechanism of catalytic oxidation of CH₄ over Pd/Co₃O₄ catalysts in electric field was proposed. The catalytic combustion of CH₄ occurs only when the temperature is higher than 250 °C normally, but when electric field was applied, the whole process of CH₄ oxidation was promoted significantly and the reaction temperature was reduced. Electric field could promote the reduction of the support Co₃O₄ to release the lattice oxygen, resulting in the increase of PdO_x and the surface chemisorbed oxygen, which could provide more active sites for the low-temperature oxidation of CH₄. Furthermore, electric field could accelerate the dehydroxylation of CoOOH to further enhance the activity of the catalysts.     

γ-氨基丁酸在发育期大鼠视皮层长时程增强中的作用

目的　探讨γ 氨基丁酸 (GABA)在发育期大鼠视皮层诱导长时程增强 (LTP)中的作用。方法　应用视皮层脑片电生理技术 ,在大鼠视皮层脑片Ⅳ层刺激而在Ⅱ /Ⅲ层记录场电位 ,在第 2、3、5周龄的大鼠脑片中诱导LTP ,并比较发育过程中LTP的发生率以及GABA在诱导LTP中的作用。结果　在第 5周龄的大鼠脑片中诱导的LTP发生率明显低于第 2及第 3周龄的大鼠。GABAA受体拮抗剂Picrotoxin能够提高第 5周龄的大鼠LTP的发生率 ,但对于第 2及第 3周龄LTP无作用。结论　GABA对于视皮层发育关键期之前LTP的诱导并无易化作用 ;但对于发育关键期后的LTP有抑制作用     

EFFECTS OF FILTER MEMBRANES ADSORBING INFLAMMATORY MEDIATORS IN HEMOFILTRATION

Sepsisischaracterizedbyreleaseofexcessiveamountofproinflammatorycytokinesinthecircu lation ,leadingtoa generalizedanduncontrolledhostresponse .Aconsiderablenumberofexperimen talandclinicalinvestigatorshavereportedemploy inghemofiltration (HF)toeliminatecytokinesandchemokines .Thisexcessiveinflammatoryresponsecouldbedownregulatedwithremovalofcytokinesandothermediators .Thesedatashowedthatthemechanismofmediatorseliminationwaslinkedtoconvectionandadsorptionbyhemofiltration .Ad sorptionappearstob…     

Simulation of temperature distribution in hot filament chemical vapor deposition diamond films growth on SiC seals

In this study, the temperature and gas velocity distributions in hot filament chemical vapor deposition(HFCVD) diamond film growth on the end surfaces of seals are simulated by the finite volume method. The influence of filament diameter, filament separation and rotational speed of the substrates is considered. Firstly,the simulation model is established by simplifying operating conditions to simulate the temperature and gas velocity distributions. Thereafter, the deposition parameters are optimized as 0.6 mm filament diameter, 18 mm filament separation and 5 r/min rotational speed to get the uniform temperature distribution. Under the influence of the rotational speed, the difference between temperature gradients along the directions perpendicular to the filament and parallel to the filament becomes narrow, it is consistent with the actual condition, and the maximum temperature difference on the substrates decreases to 7.4?C. Furthermore, the effect of the rotational speed on the gas velocity distribution is studied. Finally, diamond films are deposited on the end surfaces of Si C seals with the optimized deposition parameters. The characterizations by scanning electron microscopy(SEM) and Raman spectroscopy exhibit a layer of homogeneous diamond films with fine-faceted crystals and uniform thickness. The results validate the simulation model.     

周期性载荷作用下岩石滞回曲线的演化规律

通过不同加载速率和不同载荷水平的周期性循环载荷作用下细砂岩变形特性的试验研究,探讨了岩石在周期性载荷作用下的变形特性.结果表明:细砂岩在周期性循环载荷作用下的卸载曲线与加载曲线不重合,形成一封闭的滞回曲线,且该滞回曲线在低载荷水平下从第2次循环起逐渐趋于稳定;不同加载速率和不同载荷水平时,周期性循环载荷作用下加、卸载曲线的二次拟合参数从第2次循环起变化不大,并逐渐趋于不变;周期性循环载荷作用下,岩石变形的响应程度与加载速率和载荷水平有关.     

城乡公交一体化模式选择分析

通过对城乡公交一体化现有的运作模式进行分类,分析各种模式的优缺点,运用层次分析法构建模式选择的指标体系,得到相应的选择模型,可为城乡公交一体化的规划与实施提供依据和方法.     

基于小波变换的高速公路意外事件检测

试验表明,基于一维连续小波变换、一维离散小波变换和二维离散小波变换建立的高速公路意外事件检测模型原型具有优良的检测性能,检测在Califonia8#基础上提高了195%,同时检测时间缩短为原来的3.4%.     

工厂高压供电线路的继电保护

介绍了在工厂高压供电线路中继电保护装置的作用;提出对保护装置的基本要求,对常用的继电保护方式的原理、特点和使用进行探讨.     

顶盖前区前核痛觉调制作用的形态学探讨──HRP束路追踪和免疫细胞化学研究

应用ＨＲＰ束路追踪和免疫细胞化学技术研究了顶盖前区前核（ＡＰｔＮ）和中脑深部网状核（ＤｐＭｅ）之间的纤维联系以及ＡＰｔＮ内几种神经活性物质的分布。将ＨＲＰ注入ＤｐＭｅ后，发现在ＡＰｔＮ内有ＨＲＰ标记的神经元胞体和纤维终末，表明ＡＰｔＶ和ＤｐＭｅ之间存在着双向纤维联系。ＡＰｔＮ内的ＨＲＰ标记细胞呈背、腹两群的极性分布模式。背侧群标记细胞偏向ＡＰｔＮ吻段分布，其中有相当一部分ＨＲＰ标记细胞也是谷氨酸（Ｇｌｕ）阳性细胞，提示ＡＰｔＮ内的这群细胞向ＤｐＭｅ的投射纤维终末以释放Ｇｌｕ为主。ＡＰｔＮ内的ＨＲＰ标记纤维主要位于ＡＰｔＮ尾段的背外侧和腹侧，提示由ＤｐＭｅ到ＡＰｔＮ的传入纤维可能通过ＡＰｔＮ的背外侧和腹侧两条通路进入ＡＰｔＮ。免疫细胞化学染色显示，ＡＰｔＮ含有Ｇｌｕ、亮－脑啡肽（Ｌ－ＥＮＫ）、Ｐ物质（ＳＰ）、酪氨酸羟化酶（ＴＨ）和５－羟色胺（５－ＨＴ）免疫反应阳性胞体和／或纤维，但没有发现加压素（ＶＰ）和β－内啡肽（β－ＥＮＤ）阳性反应结构。上述阳性反应物质在ＡＰｔＮ内各有自己的分布模式，但并不以哪种活性物质为主，提示ＡＰｔＮ功能的多样性和复杂性。