基于OCSP协议的证书状态查询系统

证书状态查询是PKI系统中的一个关键问题,OCSP是解决这个问题的一种重要机制。本文分析并改进了OCSP协议,并在此基础上设计了一种高效的证书状态查询系统。文中对该系统的重要组成部分以及关键技术进行了详细的论述。     

EPS保温砂浆的性能与施工

本文比较了不同容重的EPS保温砂浆和膨胀珍珠岩砂浆的基本性能 ,提出了不同容重EPS保温砂浆的配方及其施工方法。工程应用表明 ,EPS保温砂浆完全可用于外墙外保温     

Performance evaluation of priority CSMA-CA mechanism on ISA100.11a wireless network

The International Society of Automation recently released ISA100.11a as an open standard for reliable wireless networks for industrial automation. ISA100.11a uses the TDMA scheme in the medium access layer to provide deterministic services. However, ISA100.11a adopts the CSMA-CA mechanism with priorities for retransmission from failure on dedicated links, sporadic data, and network configuration.This paper evaluates ISA100.11a CSMA-CA by simulation, considering the effects of backoff procedures and priority settings to probability of collision and successful use of slots. It's demonstrated that a high number of priority classes enable better network utilization resulting in less number of packets exceeding their lifetime.     

Texture analysis of poly-adenylated mRNA staining following global brain ischemia and reperfusion

Texture analysis provides a means to quantify complex changes in microscope images. We previously showed that cytoplasmic poly-adenylated mRNAs form mRNA granules in post-ischemic neurons and that these granules correlated with protein synthesis inhibition and hence cell death. Here we utilized the texture analysis software MaZda to quantify mRNA granules in photomicrographs of the pyramidal cell layer of rat hippocampal region CA3 around 1 h of reperfusion after 10 min of normothermic global cerebral ischemia. At 1 h reperfusion, we observed variations in the texture of mRNA granules amongst samples that were readily quantified by texture analysis. Individual sample variation was consistent with the interpretation that animal-to-animal variations in mRNA granules reflected the time-course of mRNA granule formation. We also used texture analysis to quantify the effect of cycloheximide, given either before or after brain ischemia, on mRNA granules. If administered before ischemia, cycloheximide inhibited mRNA granule formation, but if administered after ischemia did not prevent mRNA granulation, indicating mRNA granule formation is dependent on dissociation of polysomes. We conclude that texture analysis is an effective means for quantifying the complex morphological changes induced in neurons by brain ischemia and reperfusion.     

粘土对聚羧酸减水剂性能的影响及机理研究

粘土作为杂质存在于混凝土的组分如砂石中,粘土对聚羧酸减水剂有较强的吸附性,从而影响混凝土的工作性。研究了不同粘土对掺聚羧酸减水剂的水泥浆体及砂浆流动性的影响规律,探讨了聚羧酸减水剂与粘土的相互作用机理。研究结果表明,不同粘土对水泥浆体的流动性有不同程度的影响,蒙脱土和膨润土相对于高岭土及筛分土对砂浆的流动性影响更为显著;同时,相对于不掺聚羧酸的砂浆,粘土对掺聚羧酸减水剂砂浆的流动性影响更为显著。粘土自身的吸附性与疏水基的定向吸附共同作用及粘土中的金属离子与聚羧酸的螯合作用可能是粘土吸附聚羧酸减水剂的机理。     

高压喷射选用灌浆材料的探讨

高喷灌浆在使用水泥砂浆作为主材进行灌注后,板墙的稳定性和连续性得到了很大的提高,防渗效果明显,并节省了大量的水泥,有效降低了工程成本.     

超效缓粘结预应力材料试验研究

缓粘结预应力的关键技术之一是缓凝砂浆的研究．基于此试制出了缓凝期为30d以上的超效缓凝剂;并针对其凝结时间、强度、体积稳定性等进行了研究．研究得出了缓凝砂浆的强度和凝期与配比的关系,强度和凝期与温度的关系等．可见超效缓凝砂浆配置技术可广泛应用于预应力工程,应用前景广阔．     

碳化养护对冶金渣-熟石灰砂浆性质的影响

主要研究了碳化养护对冶金渣-熟石灰（SmS-SL）砂浆性质的影响,并通过XRD、真孔隙率和DTA/TG研究了影响机理和SmS-SL砂浆的环保效果.实验结果表明：碳化养护可提升SmS-SL砂浆的强度,改善它的体积稳定性和安定性.随着复合微粉中钢渣比例的提升,碳化养护对SmS-SL砂浆的增强效果逐渐提升,而对体积稳定性的改善效果却逐渐减弱.以钢渣为原料的SmS-SL砂浆的环保效果较为显著,其钢渣利用率达到27.8％,固碳率达到6.4％.     

基于废弃物利用的自保温墙体配套砂浆制备及性能研究

采用淤泥陶砂、废弃加气混凝土结合传热系数小的玻化微珠为砂浆骨料,基于"复合化"思想,制备自保温墙体配套砂浆。采用正交实验探讨混掺砂浆的合理配比,控制4项参数:胶凝材料用量、陶砂(或废料)与玻化微珠体积比、硅灰取代量和胶粉掺量,以干容重、抗压强度、导热系数为考核指标,制备综合利废效果最佳的新型混掺复合保温砂浆。结果表明,陶砂玻化微珠复合砂浆导热系数0.16～0.29W/(m.K),随着陶玻比增大而增大,因此陶砂体积含量增加有利于提高保温性能,加气废料玻化微珠复合砂浆的导热系数0.10～1.14W/(m.K),与陶砂复合保温砂浆相比,有较大的降低。     

基于Agent动态网络的疾病传播模型

提出一个基于Agent动态网络的疾病传播模型,研究疾病在人群中传播扩散的动态过程。在扩展疾病传播的SIR模型基础上,利用不同的个体状态描述各阶段病情。在二维规则网络上,通过增加个体自主移动性构建动态社会网络,并考虑个体异质性和所采取的防护措施对疾病传播的影响。仿真结果表明,该模型较好地反映了动态社会网络和个体适应性行为对疾病传播的影响,并与实际情况基本保持一致。