基于零知识证明身份认证与部分盲签名的电子货币支付模型

电子商务是通过Internet网所进行的商务活动,对于电子商务一个非常关键的要求就是要有一个安全高效的电子货币系统。本文简要分析了电子货币在网络安全方面的需求。同时,就安全电子交易提出了一个具有并行零知识证明身份认证系统以及部分盲签名技术的电子货币安全支付模型。并对此支付模型进行了详细分析和技术探讨。     

Large-scale synthesis of hierarchical alpha-FeOOH flowers by ultrasonic-assisted hydrothermal route

In this paper, we report a facile, an environmental friendly ultrasonic-assisted hydrothermal route for preparation of goethite flower structures using Fe nanopowders at low temperature (85°C). The flower structure consisted of tens of hundreds of nanowires and such structures can further self-assemble with the flake with micro size area. Structural, morphological, and elemental analysis revealed that the products consisted of flower-like structures with high structural uniformity, good crystal quality, and high yields. Influencing factors such as the reaction temperature, pH value, and the deposition time were systematically investigated. A possible formation mechanism was proposed on the basis of the experimental results. Magnetic measurements showed that the as-obtained goethite flowers exhibited weakly ferromagnetic characteristics at room temperature, which were quite different from those of the corresponding bulk materials.     

Performance of volume average scale linking in a strongly-coupled two-scale finite element methodology for polycrystalline solids

Strongly-coupled multi-scale simulations of polycrystalline solids, in which information between scales is transferred on-the-fly as needed, have gained attention as the scientific computing environment improves. Such simulations are performed combining the benefits from different scales to understand and predict the behavior of polycrystalline solids. In this research, two issues in averaging the crystal scale behavior used for the continuum scale calculation are investigated. First, the volume average polycrystal stress is compared with the surface average polycrystal stress at a material point in the continuum scale. Second, the accuracy of using the volume average polycrystal stiffness as a material stiffness in the continuum scale is investigated. The comparisons are carried out for simulation results from coupon-like specimens of two-phase polycrystalline materials under uniaxial tension. Results show that the approximate volume average stiffness and stress at the crystal scale provides adequate accuracy.     

Release behavior of active material from poly(vinyl amine)/polyelectrolyte composite hollow particles

Polyvinyl amine (PVAm) hydrogel hollow particles treated by layer-by-layer (LbL) assembly methods were fabricated. The structures of the prepared particles were confirmed through zeta-potential measurements and scanning electron microscopy (SEM). In addition, the loading amount and release rate of Chromotrope 2R (CR) from the prepared particles in each deposition step was investigated. The loading amount had an alternating tendency according to an increase in the layer number. When the outermost layer consisted of poly(sodium 4-styrenesulfonate) (PSS), CR permeation was prevented by ionic repulsion between the PSS and CR. On the other hand, CR easily permeated into the particles when the outermost layer was poly(diallyldimethyl ammonium chloride) (PDDA). The release rate was then changed by ionic interaction between the CR and the cationic polyelectrolyte and by the ionic repulsive force between the CR and the anionic polyelectrolyte. These results indicate that PVAm hydrogel hollow particles treated by the LbL method could potentially be used in the controlled release of water-soluble materials.     

Bubble Motion near a Wall Under Microgravity: Existence of Attractive and Repulsive Forces

A numerical simulation for a bubble motion near a wall under microgravity, relevant to material processing such as crystal growth in space, is presented based on a mass conservation level set algorithm to predict the bubble behavior affected by the near wall. The simulation for the wall effect on the bubble driven by an external acceleration parallel with the near wall referred to as g-jitter confirms for the first time the existence of the wall attractive force to the bubble near the wall under certain conditions such as the initial distance between the bubble and the wall, density and viscosity ratios between the bubble and surrounding liquid under microgravity. The wall effect mechanism is explained, and the results show that the wall attractive force increases with the increasing of density ratio. Moreover, the simulation for the wall repulsive effect on the bubble near the wall under microgravity has been carried out as well.     

粉末冶金结构零件焊接

讨论了最常用于连接铁基粉末冶金结构零件的各种焊接方法.资料主要来源于关于各种焊接方法的以前的出版物和文献评述.介绍了有用的设计方法与焊接技术以及各种粉末冶金材料的焊接性.     

An approximation method of origin–destination flow traffic from link load counts

Traffic matrix (TM) is a key input of traffic engineering and network management. However, it is significantly difficult to attain TM directly, and so TM estimation is so far an interesting topic. Though many methods of TM estimation are proposed, TM is generally unavailable in the large-scale IP backbone networks and is difficult to be estimated accurately. This paper proposes a novel method of TM estimation in large-scale IP backbone networks, which is based on the generalized regression neural network (GRNN), called GRNN TM estimation (GRNNTME) method. Firstly, building on top of GRNN, we present a multi-input and multi-output model of large-scale TM estimation. Because of the powerful capability of learning and generalizing of GRNN, the output of our model can sufficiently capture the spatio-temporal correlations of TM. This ensures that the estimation of TM can accurately be attained. And then GRNNTME uses the procedure of data posttreating further to make the output of our model closer to real value. Finally, we use the real data from the Abilene Network to validate GRNNTME. Simulation results show that GRNNTME can perform well the accurate and fast estimation of TM, track its dynamics, and holds the stronger robustness and lower estimation errors.     

Optimisation of location and dimension of SMC precharge in compression moulding process

The main goal of the present study is to optimise the precharge conditions such as the precharge location and dimensions that give significant effects on the mechanical performance of composite structures manufactured by the compression moulding process. As preliminary step of optimisation, we developed a manufacturing simulation program to predict the fibre volume fraction and fibre orientation. And coupled with this simulation program and a structural analysis program, a genetic algorithm (GA) is implemented to optimise the precharge conditions. The penalty function method and the repair algorithm are modified for handling constraints. The repair algorithm is applied to a symmetric structure and an arbitrary shape structure to find optimal precharge conditions.     

SF6/O2气氛中SiC ICP刻蚀的微沟槽效应

本文采用SF6 + O2作为刻蚀气体,对单晶6H-SiC 材料的感应耦合等离子体( ICP) 刻蚀工艺进行了研究。着重分析了ICP 功率、偏置电压、气体混合比等工艺参数对微沟槽效应的影响。结果表明,O2的加入对于微沟槽的形成起到了极其重要的作用,微沟槽是加入氧气后形成的SiFxOy中间层的充电造成的。ICP功率与偏置电压的增大会增强微沟槽效应,进一步促进微沟槽的形成,另外入射离子的角度分布也会影响微沟槽的形成.     

生鲜畜禽肉中沙门氏菌全基因组分析与分子溯源

依据GB 4789.4—2016对从长沙市生鲜市场随机采集的生鲜猪肉、鸡肉进行检验。结果显示:有20份生鲜猪肉样品检出沙门氏菌,检出率为83.3%;有20份生鲜鸡肉样品检出沙门氏菌,检出率为74.1%;总检出率为78.4%。通过对其中40株沙门氏菌进行全基因组测序与分子溯源研究,结果表明:20株猪源性沙门氏菌与20株鸡源性沙门氏菌按分子溯源分析可分为5个明显不同的聚类,清晰反映了沙门氏菌的污染源分布及交叉污染情况,实现了精准溯源;其中发现了15个致病基因,从基因层面阐明了沙门氏菌可能存在的致病基因与致病机制,提示了沙门氏菌潜在的致病风险;试验发现了15个耐药基因,从基因层面阐明了沙门氏菌可能存在的耐药基因与耐药机制。