Cryptanalysis of RSA for a special case with d > e

In this paper, we study the RSA public key cryptosystem in a special case with the private exponent d larger than the public exponent e. When N ^0.258 ⩽ e ⩽ N ^0.854, d > e and satisfies the given conditions, we can perform cryptanalytic attacks based on the LLL lattice basis reduction algorithm. The idea is an extension of Boneh and Durfee’s researches on low private key RSA, and provides a new solution to finding weak keys in RSA cryptosystems. Supported partially by the National Basic Research Program of China (Grant No. 2003CB314805), the National Natural Science Foundation of China (Grant Nos. 90304014 and 60873249), and the Project funded by Basic Research Foundation of School of Information Science and Technology of Tsinghua     

Effect of casting speed on microstructure,corrosion behaviour and in vivo bone reaction of Mg-rare earth alloys

In this study, two casting speeds of 10 and 30 r/min were used in vertical twin-roll casting(TRC) to obtain Mg-rare earth(MgRE) alloys, and their microstructures, corrosion behaviours and in vivo bone reactions were investigated in detail. The results indicated that the roll-castings of TRC-30 r/min exhibited a finer grain size and higher volume fraction of non-crystallization than those in castings of TRC-10 r/min. Moreover, the results of electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization indicated that the castings of TRC-30 r/min displayed a higher corrosion resistance compared with those in the castings of TRC-10 r/min. Animal tests showed that a higher degree of newly formed bone tissues was achieved by implants of TRC-30 r/min. Additionally, in vivo tests displayed that degradation properties of the TRC-30-r/min implants were better than those of the TRC-10-r/min implants; furthermore, the degradation layer was a two-layer structure, and P and Ca were enriched in the outer degradation layer. In summary, these findings elucidated that casting speed has a substantial effect on the microstructure and degradation property of Mg-based implants, and the degradation property performs better with increased casting speed.     

解决斯太尔气缸体缩松渗漏工艺研究

斯太尔气缸体的主要质量问题之一是缩松渗漏,曾多次出现大批量缩松以致气密试验漏水问题。我们进行了大量工艺试验,经过不断工艺改进,对影响气缸体缩松的一些工艺因素进行了分析探讨,找到了一种气缸体的典型熔炼生产工艺,使气缸体的缩松渗漏问题得到了有效的控制,缩松渗漏率处于1.5%以下,达到了很好的水平。1斯太尔气缸体缩松情况斯太尔气缸体为干式水套机构,铸件结构复杂。外形尺寸为969×352×363.8(m m),毛坯重量为262kg,主要壁厚为7m m。造型工艺为采用32棵砂芯组芯而成,采用立浇工艺。从生产实践来看,斯太尔气缸体对生产工艺条件比较敏…     

An analytical solution to contaminant transport through composite liners with geomembrane defects

To investigate the performance of landfill composite liner system,a one-dimensional model was developed for solute transport through composite liners containing geomembrane defects.An analytical solution to the model was obtained by the method of Laplace transformation.The results obtained by the presented solution agree well with those obtained by the numerical method.Results show that leachate head and construction quality of geomembrane(GM) have significant influences on the performance of the composite ...     

Cryptanalysis of RSA for a special case with d>e

In this paper,we study the RSA public key cryptosystem in a special case with the private exponent d larger than the public exponent e. When N0.258 e N0.854,d > e and satisfies the given conditions,we can perform cryptanalytic attacks based on the LLL lattice basis reduction algorithm. The idea is an extension of Boneh and Durfee's researches on low private key RSA,and provides a new solution to finding weak keys in RSA cryptosystems.     

刮板输送机链轮力学特性及疲劳寿命预测

为了研究不同工况下链轮力学特性和疲劳寿命,采用Ansys Workbench建立链传动系统的动力学模型,并进行瞬态动力学仿真;采用n Code Glyp Works中的Rainflow模块对提取危险区域最大等效应力时间历程进行雨流计数、载荷外推和叠加;采用n Code Glyp Works中的Stress Life模块对链轮进行疲劳寿命计算和敏感性分析。分析得到不同工况下链轮等效应力云图和最大等效应力时间历程、外推和叠加后雨流直方图、链轮损伤直方图以及不同输入参数下的链轮最小疲劳寿命曲线图和柱形图。研究结果表明:该型号链轮具有良好的力学性能,链轮的最小疲劳寿命约为110天,过载、残余应力、表面质量和平均应力修正方法均对链轮的使用寿命具有明显的影响。     

Size effect of layer thickness on stress fields due to interface core-spreading dislocation arrays in multilayers

The elastic fields due to interface dislocation arrays with spreading core in multilayers are derived analytically by means of the superposition of Green function of individual compact dislocations. The numerical results for Cu-Nb multilayers with dislocation arrays demonstrate that:(1) There exists a critical layer thickness(CLT) in describing interface shear stress. The maximum interface shear stress(MISS) increases with the layer thickness as it exceeds CLT; while the MISS decreases rapidly with the layer thickness as it is thinner than CLT.(2) Both the density and core width of interface dislocations have salient effect on the stress fields. The overall stress field is confined by high density of dislocations, and the stress singularity is released by core spreading.(3) A new dislocation prefers to glide in the middle region between the two adjacent interface dislocations by means of Peach-Kohler(P-K) force acting on the dislocation and elastic energy of dislocations. These findings would provide foundations to deepen the understanding of microscopic plastic deformation mechanisms and their related macroscopic mechanical properties of metallic anisotropic multilayers.     

Probability method for cryptanalysis of general multivariate modular linear equation

Finding the solution to a general multivariate modular linear equation plays an important role in cryptanalysis field. Earlier results show that obtaining a relatively short solution is possible in polynomial time. However, one problem arises here that if the equation has a short solution in given bounded range, the results outputted by earlier algorithms are often not the ones we are interested in. In this paper, we present a probability method based on lattice basis reduction to solve the problem. For a g...     

“西汉帝陵”大遗址的保护与规划构想

在西安和咸阳加快城市一体化进程的情况下，西汉帝陵大遗址应从整体上进行规划和利用。构想将其分成6个区，分别展示不同的古迹；在重点保护区内规划旅游路线，采取栽种植物标志、局部覆罩等手段展示遗存；在一般保护区内建设内部道路、陈列馆等；在建设控制地带设置停车场、变电站等服务设施。