芝加哥将开行特快地铁列车

芝加哥O’Hare国际机场和Midway机场在已经拥有地铁连接的情况下，即将开行特快地铁列车，以进一步减少运行时间，提高乘车的舒适性和可靠性。长时间以来，芝加哥一直就是运输中心，其运输中心生涯起始于战略水陆联运中心，后来，又成为美国铁路网的连接中心。现在它拥有世界最繁忙的机场——O’Hare国际机场，同时它又是一个旅游中心。     

提高铁路货物及时送达可靠性的途径

对货物及时送达可靠性的内涵进行界定,认为及时运输是货物运输的共同要求.从更新硬件设施、实行差别化策略、推进运输代理制度、健全运输法规、建立考核制度、推进信息化建设和整合货运系统等方面提出提高货物及时送达可靠性的途径.     

现代轮机工程系列讲座（十四）——油液检测技术及其应用（3）

人所共知，原子由原子核和绕核在固定轨道上旋转的若干电子组成，例如镍有28个电子，铜有29个电子，原子内部能量的变化可以是核的变化也可以是电子的变化。我们注意到外部电子转变是能量的变化，作为这些转变的结果所吸收和发射的光，相当于紫外线和波长在0.2μm-0.8μm范围内的能谱可见区。     

高速柴油机正时传动部分的优化研究

本文通过对某柴油机失效分析，设计了正时传动部分的优化方案，提高柴油机的可靠性，并通过了试验验证。     

I—5—4产品工艺设计中可靠性分析的运用

在I—5—4产品的原材料到镦饼工序，采用FMEA进行过程的可靠性分析，改进工艺设计，降低裂纹的发生频度，从而降低裂纹的产生风险，达到提高过程可靠性的目的。因此进行过程FMEA分析可以提高工艺设计水平，提高产品质量。     

DESIGN OF A DIGITAL SIGNATURE SCHEME BASED ON FACTORING AND DISCRETE LOGARITHMS

Objective Focusing on the security problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key cryptosystem. Methods Firstly,the course of digital signature based on the public key cryptosystem was given. Then, RSA and ELGamal schemes were described respectively. They were the basis of the proposed scheme. Generalized ELGamal type signature schemes were listed. After comparing with each other, one scheme, whose Signature equation was (m r)x=j s modФ(p) , was adopted in the designing. Results Based on two well-known cryptographic assumptions, the factorization and the discrete logarithms, a digital signature scheme was presented. It must be required that s“ was not equal to p‘q“ in the signing procedure, because attackers could forge the signatures with high probabilities if the discrete logarithms modulo a large prime were solvable. The variable public key “e“ is used instead of the invariable parameter “3“ in Ham‘s signature scheme to enhance the security. One generalized ELGamal type scheme made the proposed scheme escape one multiplicative inverse operation in the signing procedure and one modular exponentiation in the verification procedure.Conclusion The presented scheme obtains the security that Harn‘s scheme was originally claimed. It is secure if the factorization and the discrete logarithms are simultaneously unsolvable.     

秦沈客运专线桥梁检验工作全面展开

秦沈客运专线是十五期间铁道部十大标志工程之首,是我国铁路自主知识产权的速度200ｋｍｈ以上高速客运专线。整个工程建设采用了很多新方法、新技术、新工艺、新材料和新设备,其中之一就是现场预制桥梁的质量管理与监督。经过反复研究讨论,部决定对预制后张法预应力混凝土箱型简支梁(简称“箱梁”)采取生产条件认可证、施工监理与监督抽查相结合,对预制后张法预应力混凝土铁路桥简支梁(简称“Ｔ梁”)按规定采取生产许可证与施工监理相结合的质量监督管理方式。同时要求部质检中心在部科教司领导下,具体负责生产许可证、生产条件认可证发证考…