Apply geometric duality to energy-efficient non-local phenomenon awareness using sensor networks

A powerful concept to cope with resource limitations and information redundancy in wireless sensor networks is the use of collaboration groups to distill information within the network and suppress unnecessary activities. When the phenomena to be monitored have large geographical extents, it is not obvious how to define these collaboration groups. This article presents the application of geometric duality to form such groups for sensor selection and non-local phenomena tracking. Using a dual-space transformation, which maps a non-local phenomenon (e.g., the edge of a half-plane shadow) to a single point in the dual space and maps locations of distributed sensor nodes to a set of lines that partitions the dual space, one can turn off the majority of the sensors to achieve resource preservation without losing detection and tracking accuracy. Since the group so defined may consist of nodes that are far away in physical space, we propose a hierarchical architecture that uses a small number of computationally powerful nodes and a massive number of power constrained motes. By taking advantage of the continuity of physical phenomena and the duality principle, we can greatly reduce the power consumption in non-local phenomena tracking and extend the lifetime of the network.     

LF6铝合金的超塑性／扩散连接组合工艺试验及理论研究EI

本文研究了ＬＦ６铝合金的超塑性／扩散连接组合工艺，用变形和再结晶的方法细化晶粒，成功地进行了ＳＰＦ／ＤＢ工艺试验，利用电子探针观察了扩散连接接头的界面微观区域，并从机理上分析了金属的超塑性／扩散连接两种工艺之间的内部联系及其金属学行为。     

露天煤矿卡车运输轮胎消耗的原因分析及控制措施

通过分析黑岱沟露天煤矿轮胎消耗的主要原因，制定相应措施，降低轮胎消耗，降低生产成本。     

Power levels and packet lengths in random multiple access with multiple-packet reception capability

This paper extends our earlier results. We assume that the receiver has the capability of capturing multiple packets so long as the signal-to-interference-plus-noise ratio (SINR) of each packet is above a designed threshold T throughout its transmission period. We prove that, compared with a multiple-power-level system, the single-power-level system in which all nodes transmit at the maximum allowable power level achieves optimal throughput, under a condition that T exceeds the value 3.33. Given a minimum throughput requirement, under the same condition on T, the single-power-level system also achieves the maximum average packet capture probability as well as the optimum energy usage efficiency. If the multiple-power-level systems are constrained such that higher power levels always have shorter packet lengths, then the above results hold for T greater than 2.     

基于旋量和臂形标志的机器人运动学逆解计算

讨论了用旋量和指数积公式计算PUMA类型6自由度机器人运动学逆解的方法。在子问题的计算过程中，通过引入臂形标志来选取关节变量的合理解，以得到运动学逆解的唯一解。这种方法避免了对无效解的计算，可以减少计算量，提高计算效率。通过一个实验机器人的运动学逆解计算验证了算法的有效性。     

加强电炉钢短流程生产工艺研究与技术开发的建议

论述了加强电炉钢短流程生产工艺研究与技术开发的必要性和主要课题，并提出关于组织合金钢短流程生产工艺研究与技术开发“九五”国家科技攻关及提高高研究开发投资强度的建议。     

Dissolution processes,hydrolysis and condensation reactions during geopolymer synthesis: Part II. High Si/Al ratio systems

The mechanisms of speciation of aluminate and silicate phases during dissolution and condensation stages of alumino-silicate geopolymer reactions characterised by Si/Al ≥ 3, have been investigated and the results compared to predictions of the partial charge model. Solid-state nuclear magnetic resonance (NMR) traces indicate that free [Al(OH)₄]⁻ species, present in lower silicate formulations such as Si/Al ≤ 1, do not occur in the present systems, suggesting that the condensation reaction between [Al(OH)₄]⁻ and silicate species is fairly quick and is consumed as soon as it is formed. This observation is also consistent with both calorimetric measurements and model predictions, as the condensation time increased exponentially with increased Si/Al ratio in the geopolymeric phase, indicating again that the high content of Al species in the gel phase greatly enhanced the condensation rate. The experimental observations suggest that the condensation process in these systems occurs in two stages: (a) quick condensation between aluminate and silicate species; followed by (b) a slow condensation stage solely involving silicate species.     

基于遗传算法的工作辊温度场参数优化模型

针对热连轧机工作辊热辊形计算中温度场模型的热交换等参数难以确定的问题 ,建立了基于遗传算法的参数优化模型 ,可以解决复杂条件下的热参数的求解问题。利用优化参数计算的轧辊温度场与实际测量结果一致。