主丛与刚体运动

本文给出了刚体运动的主丛描述,从而为刚体运动的研究提供一个新的数学方法。     

对称群作为正交群的子群的n-无关分歧律

本文利用Schur函数的相增和Schur级数给出了对称群作为正交群的子群的一般表示和自旋表示n-无关的分歧律。     

A measure of centrality based on modularity matrix

In this paper, a kind of measure of structural centrality for networks, called modularity centrality, is introduced. This centrality index is based on the eigenvector belonging to the largest magnitude eigenvalue of modularity matrix. The measure is illustrated and compared with the standard centrality measures using a classic dataset. The statistical distribution of modularity centrality is investigated by considering large computer generated graphs and two networks from the real world.     

无限深势阱中引入势壁后的能量本征态

讨论了无限深势阱中引入势壁后的宇称态和能级,在极限情况下, 能级可以有简并,并用计算机绘出能级图.     

现代铬系抗磨白口铸铁的应用与发展

综述了国内外现代铬系白口铸铁的应用和发展状况 ,介绍了其强韧化的主要方法 ,作者还就目前铬系白口铸铁生产及控制方面的问题提出了看法     

Scheduling Non-stationary Bursts of Real-time and Non-real-time Traffic in ATM Networks

The problem of scheduling real-time and non-real-time traffic in an ATM switch multiplexor when bursts of either type of traffic occur is studied. The scheduling algorithms studied are: Queue Length Threshold (QLT) and Minimum Laxity Threshold (MLT). Analytic results based on Markov Chains are used. In addition the results are compared with an optimal (but impractical) scheduling determined via dynamic programming. Dynamic programming is used in this paper to show that MLT gives a near optimal performance trade-off between real-time and non-real-time traffic for constant arrival rates. The trade-off QLT allows is not close to optimal. For non-real-time bursts MLT still gives a close to optimal trade-off. For real-time bursts the trade-off MLT allows between real-time and non-real-time traffic is not as close to optimal, but even where the MLT trade-off is not near optimal, the QLT trade-off is much worse than the MLT trade-off.     

纳米TiO2-Pt修饰电极的制备及电催化性研究

以钛酸丁酯为原料,采用溶胶-凝胶法（sol—gel）制备了纳米TiO2（nano—TiO2）粉末,用FTIR和激光粒度分析仪测定了合成纳米TiO2的红外光谱特征及其粒径;用循环伏安法研究了裸Pt电极和涂膜法制备的Pt／nano—TiO2修饰电极在不同浓度的Mn^2＋溶液中的循环伏安特征。研究结果表明合成的纳米TiO2颗粒粒径为300-400nmTiO2修饰电极对Mn^2＋具有较好的电催化性能。     

有向无标度网络灾害扩散动力学行为研究

分析了有向网络上灾害扩散的动态模型,将模型演化的最终形态分为系统稳定、波动与崩溃3种情形.以节点的修复率作为衡量灾害扩散程度的量化指标.探讨了在指数可调的有向无标度网络上,灾害随时间的扩散情况以及自修复因子和节点阈值对灾害扩散的影响.仿真结果表明.自修复因子存在2个临界值.对应着系统的3种状态之间的转换.随着无标度网络幂律指数的增大.灾害扩散程度降低.最后,利用网络节点的集线中心权重指标建立了灾害预防与控制策略.     

关于城市建设中园林绿化用土问题的探讨

在园林绿化中,结合自身特点,对土壤的使用和质量要求应尊重自然,合理规划,寻求人与生存环境之间的最佳关系,开发建设时,好的土壤应储备,建立土壤信息共享网,合理调配,实施绿化用土储备制度.对土壤较差地实行生态改良,确保园林绿化土壤的优质合理使用.     

浅谈工程施工中的安全管理

安全管理是企业生产的保障,由于施工项目的流动性大、高空作业多、作业条件差,建设管理水平参差不齐,影响施工安全的因素多,科学管理对做好安全工作来讲是极其必要的。