Influence of surface integrity on fatigue strength of 40CrNi2Si2MoVA steel

Influence of surface integrity (including surface roughness, residual stresses, and microstructure in surface) on fatigue limit of 40CrNi2Si2MoVA steel specimens is investigated comprehensively in this work according to a systematic consideration. The surface integrity of specimens is changed due to several widely used manufacturing procedures: heat-treatment, grinding, electro-polishing, hard chromium plating and shot peening. In comparison with specimen electro-polished after grinding, the specimen without polishing has 10% lower fatigue limit due to higher surface roughness; while shot peening improves the fatigue limit for about 36% due to inducing of compressive residual stress field in the surface and transferring the fatigue crack source from surface to interior. The fatigue limit of specimen with decarburized layer after grinding is lower about 13%, but the shot peening can eliminate its detrimental effect. Hard chromium plating decreases the fatigue limit dramatically. The shot peening carried before plating can improve the fatigue limit of specimen and cause it to get to a level even higher than that of specimen without plating.     

数字签名应用标准化初步模型

本文分析了数字签名的优势和潜力,指出了数字签名技术的广阔应用前景,同时阐明了建立相关标准的重要性,并且提出了一个数字签名技术应用的通用的模型.     

塔里木盆地超深层油气藏试油与储层改造技术进展及发展方向

近年来，中国石油塔里木油田公司（以下简称塔里木油田）在塔里木盆地超深层油气勘探陆续取得重大突破。这与其超深层试油与储层改造技术的进步是密不可分的，随着超深井的逐渐增多，试油与储层改造技术仍需要持续升级、完善。为此，通过总结塔里木油田试油与储层改造技术的发展历程，系统梳理了其在超深层油气藏试油与储层改造方面取得的主要技术进展，并结合新的勘探开发形势与要求，指出了塔里木盆地超深层油气藏试油与储层改造技术今后一个时期的发展方向。研究结果表明：①塔里木油田已形成了一系列专项技术——超深高温高压气井安全快速测试技术，超深层、高含硫、缝洞型碳酸盐岩气藏完井试油一体化技术，超深层缝洞型碳酸盐岩储层深度改造技术，以及超深层、高温高压裂缝性致密砂岩气藏储层缝网改造技术，支撑了该盆地超深层油气藏的陆续勘探突破和持续高效开发；②随着油气勘探开发深度领域迈向9 000 m，储层地质条件更加复杂，完井试油与储层改造技术面临着新的技术难题；③今后将围绕“可靠、安全、高效”的目标进行试油完井工具和工艺的持续升级和改进，需要不断完善储层改造地质工程一体化设计、改造工作液和材料以及耐高温高压工具和装备，以支撑精细化缝网体积改造；④新形势下，为了满足井完整性的要求，需要完善相关配套技术，同时建立套管磨损评价与地面管汇剩余寿命检测方法，以保障试油和储层改造工艺的顺利实施。结论认为，该研究成果可以为国内外超深层油气藏的安全高效建井与提产提供借鉴。     

Disruption of Membrane Integrity as a Molecular Initiating Event Determines the Toxicity of Polyhexamethylene Guanidine Phosphate Depending on the Routes of Exposure

Polyhexamethylene guanidine phosphate (PHMG-P), a cationic biocide, is widely used in household products due to its strong bactericidal activity and low toxicity. However, it causes fatal lung damage when inhaled. In this study, we investigated why PHMG-P causes fatal lung injury when inhaled, and demonstrated that the disruption of membrane integrity through ionic interaction—a molecular initiating event of PHMG-P—determines toxicity. Mice were injected intravenously with 0.9 or 7.2 mg/kg PHMG-P (IV group), or instilled intratracheally with 0.9 mg/kg PHMG-P (ITI group); they were euthanatized at 4 h and on days 1 and 7 after treatment. Increased total BAL cell count and proinflammatory cytokine production, along with fibrotic changes in the lungs, were detected in the ITI group only. Levels of hepatic enzymes and hepatic serum amyloid A mRNA expression were markedly upregulated in the 7.2 mg/kg IV and ITI groups at 4 h or day 1 after treatment, but returned to baseline. No pathological findings were detected in the heart, liver, or kidneys. To simulate the IV injection, A549, THP-1, and HepG2 cells were treated with PHMG-P in cell culture media supplemented with different serum concentrations. Increased serum concentration was associated with an increase in cell viability. These results support the idea that direct contact between PHMG-P and cell membranes is necessary for PHMG-induced toxicity.     

Investigation of a Novel Catalyst Coated Membrane Method to Prepare Low‐Platinum‐Loading Membrane Electrode Assemblies for PEMFCs

In this work, a novel catalyst coated membrane (CCM) approach–a catalyst‐sprayed membrane under irradiation (CSMUI)–was developed to prepare MEAs for proton exchange membrane fuel cell (PEMFC) application. Catalyst ink was sprayed directly onto the membrane and an infrared light was used simultaneously to evaporate the solvents. The resultant MEAs prepared by this method yielded very high performance. Based on this approach, the preparation of low‐platinum‐content MEAs was investigated. It was found that for the anode, even if the platinum loading was decreased from 0.2 to 0.03 mg cm^–2, only a very small performance decrease was observed; for the cathode, when the platinum loading was decreased from 0.3 to 0.15 mg cm^–2, just a 5% decrease was detected at 0.7 V, but a 35% decrease was observed when the loading was decreased from 0.15 to 0.06 mg cm^–2. These results indicate that this approach is much better than the catalyst coated gas diffusion layer (GDL) method, especially for the preparation of low‐platinum‐content MEAs. SEM and EIS measurements indicated ample interfacial contact between the catalyst layer and the membrane.     

Molecular dynamics simulation of water transport through graphene-based nanopores: Flow behavior and structure characteristics

The flowbehavior of pressure-drivenwater infiltration through graphene-based slit nanopores has been studied by molecular simulation. The simulated flow rate is close to the experimental values, which demonstrates the reasonability of simulation results. Water molecules can spontaneously infiltrate into the nanopores, but an external driving force is generally required to pass through the whole pores. The exit of nanopore has a large obstruction on the water effusion. The flow velocity within the graphene nanochannels does not display monotonous dependence upon the porewidth, indicating that the flowis related to the microscopic structures ofwater confined in the nanopores. Extensive structures of confined water are characterized in order to understand the flow behavior. This simulation improves the understanding of graphene-based nanofluidics, which helps in developing a new type of membrane separation technique.     

诚实信用原则的制度构建与实践应用

诚信是社会正常运行所必不可少的社会规则。诚信既是道德规范,又是法律规范。作为道德要求的诚信必须首先在法的制定过程中被固定为法律原则,使其具有全局性的指导意义。立法时要设置违反诚实信用原则的法律后果,并且该法律后果必须达到足够的惩戒效应。诚信缺失已具有普遍化趋势,社会各领域都不同程度存在诚信危机。因此,诚信的法制化必须覆盖整个法律体系。对社会诚信建设可分为公民诚信、政府诚信、商业诚信和司法诚信四个方面,分别根据这四方面的不同特点采取适当的法制措施加以治理。     

一种抑制同步开关噪声的微波光子晶体结构

为了确保抑制高速电路中同步开关噪声(SSN)的微波光子晶体(EBG)结构在兼顾带隙特性的同时,还具有良好的信号完整性,采用枝条绕转单元贴片的方法设计出一种新型EBG结构。利用HFSS软件对新型EBG结构抑制SSN的特性进行建模仿真,并制备刻蚀有新型EBG结构的4层印制电路板,用安捷伦矢量网络分析仪对其禁带特性进行测试,实验结果与仿真结果吻合良好。通过眼图对新型EBG结构进行的仿真分析显示,新结构的信号完整性良好。     

一种高效的虚拟桌面可信保证机制

虚拟桌面系统与传统PC桌面系统结构的不同,导致其在保证安全机制自身可信的同时,也会带来“语义差别”和效率降低等问题。本文提出了一种安全虚拟机完整性监控机制SVMIM（Security Virtual Machine Integrity Monitor）。SVMIM采用混杂模式的安全结构,基于可信计算技术对虚拟桌面系统的代码加载过程进行监视和控制,有效克服“语义差别”问题,并保证安全机制自身的可信;同时,SVMIM基于虚拟桌面网络引导机制,在网络存储端使用存储克隆技术,最大程度地降低安全机制对系统性能的影响。系统性能分析和基于SVMIM原型系统进行的实验表明该技术是可行的,并且相对于传统的虚拟桌面安全保障方案具有较大的性能优势。     

切削加工表面完整性建模现状与发展趋势

针对切削加工表面完整性建模方法种类繁多且相互关系揭示不明等问题,总结了各表面完整性指标,包括表面形貌、残余应力、加工硬化和相变的主要建模方法,并从各建模方法的应用范围以及主要成果的角度概括了表面完整性建模的研究现状.论述了解析建模与数值建模方法在预测表面完整性各指标时的优缺点及内在联系,重点分析了数值模拟技术在表面完整性建模中的作用.指出了国内外表面完整性研究体系的区别及联系,并对表面完整性建模的发展方向作了展望.