一种用于流交换的代理重签名方案

为了解决大规模复杂网络环境下流交换的安全问题,首次将代理重签名技术应用到安全流交换中,提出一种用于流交换的基于陷门Hash函数的代理重签名方案.首先,针对陷门Hash函数在流交换应用中存在的密钥泄露问题,提出一种新的基于椭圆曲线的无密钥泄露的陷门Hash函数(EDL-MTH),并对其安全性加以证明;然后,基于EDL-MTH构造了一个在随机预言模型下可证明适应性选择消息攻击安全的代理重签名方案;最后,通过一个示例分析了该方案在安全流交换中的应用和性能.     

细节高度复杂表面模型的视点相关渐进传输

针对细节高度复杂模型的特点,提出一种视点相关的渐进传输方法.根据人的视觉特征,算法将模型表示为多分辨率的四边形参数面片和表面法向细节纹理.该算法利用法向映射提高传输和绘制的效率,然后随着视点的变化动态细化和传输当前视点下轮廓部分的参数面片信息,从而最大限度地减少了模型传输时面片的数量.参数面片的结构规则,面片之间关联性低,因此能够按任意顺序高效地传输,从而实现真正的视点相关传输,并可以采用有效的编码方法对其结构和几何信息进行压缩.实验结果表明了该算法的有效性,特别适合于表面细节复杂的表面模型的交互传输和绘制.     

Comparison of dehydriding kinetics between pure LaNi5 and its substituted systems

The kinetic mechanisms of dehydriding reaction in La_0.8M_0.2Ni₅ and LaNi_4.5T_0.5 were comparatively investigated by the Chou model and the first order model, and the former was superior to the latter from the comparison of theoretical calculated results and experimental data. According to the characteristic time (t_c) in the Chou model, substituting La (t_c = 71.36 s) with Ce (t_c = 35.64 s), Nd (t_c = 30.82 s) and Pr (t_c = 28.86 s) increased the dehydriding reaction rate, but partial substitution of Ni (t_c = 71.36 s) with Co (t_c = 102.29 s), Fe (t_c = 116.70 s) and Cu (t_c = 120.62 s) decreased the hydrogen desorption reaction rate. The Chou model was also used to discuss the effect of different amount of Ni substituted with Fe and Co. The dehydriding reaction rates of La(Ni_1−xFe_x)₅ increased with x leveling from 0 to 0.20 but decreased with x increasing from 0.20 to 0.30, while that of LaNi_5−yCo_y decreased with increasing the amount of Co from 0 to 3.00. In addition, the Chou model was successfully applied to predicting the kinetic properties of LaNi_4.8Sn_0.2 at 40 °C and 60 °C, which exhibited an excellent agreement with the experimental data.     

板栗淀粉的性质研究

淀粉是板栗的主要成分,其结构和性质直接关系到板栗的加工和应用。本文研究了板栗淀粉的表面结构、偏光十字、X-衍射图谱和结晶结构、粘度曲线等特性,以及淀粉乳浓度、温度、pH值、常用食品添加剂等对板栗淀粉糊粘度的影响,为开发板栗深加工产品提供理论基础。     

Microstructure and properties of W-4.9Ni-2.1Fe heavy alloy with Dy_2O_3 addition

The W-4.9 Ni-2.1 Fe-xDy_2 O_3 heavy alloy was fabricated by high-energy ball milling and spark plasma sintering(SPS)technique,and the microstructure,mechanical and friction behavior and anti-corrosion ability were investigated by scanning electron microscope(SEM),Rockwell hardness tester,X-ray diffraction(XRD),reciprocating friction and wear tester,electrochemical station,etc.The results show that the trace Dy_2 O_3 particles,which mainly distributes in the W-M(tungsten-matrix)interface and the tungsten matrix phase,can dramatically decrease the tungsten grain size and the amount of O and P impurities aggregating in the interface,promote the γ-(Ni,Fe)bonding phase and tungsten particles uniform distribution,and increase the relative density,hardness,and wear and corrosion resistance properties.But the excessive Dy_2 O_3 addition can make the inhibition effect weaken,resulting in the decrease in the comprehensive performances of the alloy.So,the amount of Dy_2 O_3 should be appropriate.When the adding amount of Dy_2 O_3 particles is 0.7 wt%,the comprehensive performances of the heavy alloy are the best.     

蓝光发光性能优异的氧化锌空心微球的制备及表征

本工作采用低温溶剂水浴热法, 以葡萄糖、柠檬酸盐为辅助剂, 首先制备了柠檬酸锌空心微球, 然后在空气气氛中500℃煅烧制得ZnO空心微球。应用XRD、TG-DSC、SEM、TEM、IR对产物的组成、结构以及形貌进行了研究, 研究发现该方法制备的前驱体为直径约为2 μm, 壁厚约为200 nm的空心微球。由前驱体煅烧后得到的ZnO空心微球由粒径为20~30 nm的纳米粒子组装成, 平均直径约为1 μm, 壁厚约为100 nm。此外还采用光致发光光谱仪(PL)对产物的光学性能进行了研究, 结果表明ZnO空心微球在激发波长为325 nm的条件下具有较好的蓝光发光性能, 发光峰位于469 nm处。     

简易凝胶柱净化-气相色谱法检测动物源性 样品中残留的敌敌畏

目的建立动物源样品中敌敌畏的简易凝胶色谱净化-气相色谱检测方法。方法采用凝胶净化粉湿法装填于玻璃层析柱,制成长约15 cm、直径1 cm的简易凝胶净化柱,对样品的净化洗脱液进行分段收集,分析其中敌敌畏回收率的规律。结果最终确定4.6~25 m L体积段的洗脱液为敌敌畏的最佳洗脱体积段,乙酸乙酯-环己烷(6:4,V:V)为最优配比的洗脱溶液,凝胶柱装填3.00 g凝胶粉时净化效果最佳。选取猪肉、牛肉、鸡肉、鱼肉样品,进行确证试验,回收率和变异系数均满足精确度要求,方法检出限为0.003μg/m L,加标回收率为88.2%~100.7%,相对标准偏差为0.4%~1.2%。结论该方法快速、灵敏、准确,适合动物源性食品中敌敌畏的测定。     

饱和CO_2盐溶液中镍基合金和碳钢的电偶腐蚀行为

在油田中管材应用种类繁多,难免存在不同材料的耦接使用。应用电化学法和溶液浸泡方法研究了P110SS-Inconel 718两种材料耦接的电偶对在含高Cl-的饱和CO2溶液中的电偶腐蚀行为,用扫描电镜(SEM)观察电偶对材料浸泡后的腐蚀形貌。结果表明:在Cl-浓度不变的情况下,随着溶液介质温度的升高,两种材料的自腐蚀电位均有不同程度的降低;耦接后,电偶对的电偶电流密度随着温度的升高而增大,表面腐蚀坑明显增深。浸泡试验表明:耦接后作为阳极的P110SS的腐蚀程度相比单独浸泡时加剧。     

超声辅助合成CeF3纳米晶及其表征

用超声波辅助法制备了CeF3纳米晶.并用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线粉末衍射(XRD)、紫外吸收(UV)光谱和荧光光谱(PL)对纳米晶的结构与性能进行了表征.结果表明:超声时间对所制备的CeF3纳米晶的形貌有很大的影响.随着超声时间的延长,所制备样品的形貌由"笼形"演变为规整的盘形.随着样品粒径的减小,纳米晶的紫外吸收峰和吸收带边发生明显的蓝移.纳米晶的荧光强度与纳米晶的结晶程度有关.