OpenStack认证后端的安全性研究与改进

OpenStack作为当今最流行的开源云平台,在当前的使用过程中其安全性也越来越受到人们的重视和研究.本文在分析Openstack平台架构的基础上,重点分析了openstack认证组件keystone的工作原理,以及用户在登陆云平台时keystone的交互过程.以keystone作为openstack 身份认证安全性问题的切入对,提出了其认证后端数据库利用率和安全性不足的问题,并以LDAP轻量级目录服务协议为基础提出了openstack认证后端的安全性改进方案.     

Electrospinning and rheological behavior of poly (vinyl alcohol)/collagen blended solutions

Poly(vinyl alcohol)/collagen (PVA/COL) micro-nanofibers were successfully prepared by electrospinning process. Water, green, and non-toxic was used as the solvent. The electrospun mats consisted of micro-nanoscale fibers with mean diameter ranging from approximately 363 nm to 179 nm. It was observed that the mean diameters of PVA/COL electrospun fibers decreased with increasing collagen content. The effects of PVA/COL blending ratio on the rheological behavior of PVA/COL blended solutions were investigated by rotate rheometer. It was found that PVA/COL blended solutions behaved as Non-Newtonian fluids. With increasing collagen content, the Non-Newtonian index (n) of PVA/COL blended solutions decreased. Meanwhile, a linear relationship was found between the Non-Newtonian index (n) and the mean diameters of the PVA/COL micronanofibers. The chemical structures of PVA/COL electrospun fibers were also characterized by FTIR.     

粉煤灰悬浮胶体的悬浮稳定性实验研究

针对煤矿生产中粉煤灰防(灭)火材料管路输送的管路阻塞问题,选择SC1,SC2,SC3,SC4,SC5,SC6,SC7和SC8共8种悬浮剂,配制成4种质量分数分别为0.5%,1.0%,1.5%和2.0%的粉煤灰悬浮胶体,采用沉降分析方法,研究其悬浮稳定性。结果表明:各粉煤灰悬浮胶体沉降速率出现类似"L型"变化,沉降到一定时间均达到平衡状态;悬浮剂可以减小粉煤灰悬浮体沉降速率变化,质量分数越低,初始沉降速率越大,质量分数越高,沉降速率变化越小;同时也可增大粉煤灰悬浮率,增加悬浮胶体的稳定性。     

Leaching Stability of Simulated Waste Forms for Immobilizing An3＋ by Gd2Zr2O7 with Nd3＋

In order to investigate the anti-leaching capability of pyrochlore Gd2Zr2O7 immobilized An3+, trivalent neodymium was used as the simulacrums for radioactive wastes with trivalence, Gd2-xNdxZr2O7(0.0x 2.0) series samples were successfully synthesized by high temperature solid reaction and using Gd2O3, Zr O2 powders as starting materials. The experiments of long-term chemical stability were conducted in synthetic seawater at 40 and 70 ℃. The XRD diffractive data and extraction ratio of as-received samples were collected with the help of X-ray diffraction(XRD) instrument and inductively coupled plasma mass spectrometry(ICPMass). The results indicate that the phases of as-received compounds keep the single phase of pyrochlore. The extraction ratio of Gd3+, Zr4+ and Nd3+ in waste forms is increasing with the increase of immersion time in synthetic seawater. The extraction ratio of waste forms at 70 ℃ is higher than at 40 ℃. The highest extraction ratio of Gd3+, Zr4+ and Nd3+ after 42 days is near 0.025 8, 0.003 8 and 0.045 2 μg·m L-1, respectively.     

北美规范与中国规范关于冷弯薄壁型钢C形截面受压构件设计的比较

对比了北美规范CSA S136-07和中国规范GB 50018-2002中关于冷弯薄壁型钢C形截面轴压构件的名义轴压强度。首先介绍了北美规范和中国规范计算名义轴压强度的方法,然后针对控制构件名义轴压强度的2个主要参数,即屈曲应力和有效截面面积,对2本规范进行了深入对比,最后对典型C形墙架柱名义轴压强度进行了比较。研究结果表明：2本规范具有相同的屈曲应力,但依据2本规范计算的有效截面面积却不同;一般来说,根据GB 50018-2002计算的翼缘有效宽度远小于根据CSA S136-07计算的结果,然而依据CSA S136-07计算的腹板有效宽度则略小于依据GB 50018-2002计算的结果;2本规范名义轴压强度不同主要由C形截面翼缘和腹板有效宽厚比不同引起;当翼缘的宽厚比不小于17．8时,构件名义轴压强度的不同主要由翼缘有效宽厚比控制,根据GB 50018-2002计算的名义轴压强度小于根据CSA S136-07计算的结果;当翼缘的宽厚比小于17．8时,构件名义轴压强度的不同则主要受腹板有效宽度控制,依据GB 50018-2002计算的名义轴压强度略大于依据CSA S136-07计算的结果。     

弱势群体参与群体性事件利益博弈心态分析──基于风险社会视阈下的审视

风险社会中群体性事件的发生往往伴随着弱势群体与基层管理方的利益博弈,而在风险社会视域下审视弱势群体的利益博弈心态,消除公共信息的不对称,找寻博弈双方的利益博弈均衡点,是解决群体性事件利益纷争的有利前提,亦是规避社会风险的有效途径。由此,正确引导博弈各方理性抗争,一方面使得弱势群体合理归因社会矛盾、充分理解社会改革中的客观因素;另一方面基层管理自觉调整强势角色,搭建弱势群体的利益表达平台,实现双方平等对话。在此基础上,作为平衡社会信息的媒体更需要合理设置议程、为博弈双方提供对称信息以期化解社会风险。     

具有输入与状态时变时滞线性系统的鲁棒H_∞控制

针对具有输入与状态时变时滞的线性系统研究其鲁棒控制问题,依据自由权矩阵技巧,在没有任何不等式放缩的情况下,利用Lyapunov稳定性定理,得到了没有任何保守性的时滞依赖渐近稳定充分条件;所用方法对时滞的导数没有任何限制,适合任何慢变或快变系统。最后通过数值算例与其他文献结果进行比较,说明该方法的优越性。     

500kV复合绝缘子红外测温诊断分析

本文介绍了山东电网一起红外测温发现的500kV复合绝缘子外护套损坏案例,分析了损坏的原因,阐述了红外测温带电测试技术诊断复合绝缘子内部缺陷的机理和判别方法,测温结果及实验室试验表明红外成像法能够有效地检测出缺陷复合绝缘子,并给出了提高复合绝缘子安全运行水平的措施和建议。     

程序设计实践课程将训练目标落实到位的尝试

本文提出大众化教育时代程序设计实践课程分层教学理念,说明保证上规模的训练可达时,照顾能力、兼顾兴趣的实践训练任务设计思考,减少复制的监督与管理措施,以及全面评价的方法,并分析实践效果。     

木屑生物质活性炭脱除气体SO2的实验研究

以木屑作为制备生物质活性炭的原料,对比研究未改性、采用氨水和NaOH活化对SO2吸附性能的影响,以探讨木屑生物制活性炭对SO2吸附的可行性。研究结果表明随着吸附时间的增加,未活化的、氨水活化以及NaOH活化的木屑炭对SO2的吸附量都增加;活化后的木屑炭吸附SO2的性能比未活化的木屑炭要好;NaOH活化的木屑炭比氨水活化的木屑炭吸附SO2能力强,NaOH比氨水的活化效果更好。采用生物质活性炭来吸附烧结烟气中的SO2是可行的。