纳米铜对粉末冶金渗碳齿轮件组织与性能影响

将质量分数为为3%的纳米Cu与一定比例的Cr、Mn、Ti粉末与Fe基体粉末通过高能球磨机均匀混合,经过压制成形、烧结和渗碳处理过程,制成粉末冶金块体材料.用扫描电子显微镜和透射电子显微镜进行组织结构分析,并与传统20CrMnTi汽车齿轮制品进行性能的对比分析.结果表明:少量的纳米Cu在Fe基颗粒界面上通过扩散、熔解,促进了Fe基颗粒的有效连接和传质扩散,在Fe基颗粒界面形成Cu相;添加少量纳米Cu可以显著降低粉末冶金加工时的烧结温度,同时制成的20CrMnTi粉末冶金制品在性能上也更具有优势.     

三菱M701F燃气轮机叶片冷却技术分析

提高燃气轮机进口初温是提高其效率的有效方法,这在一定程度上受到透平热部件结构强度的限制,而采用先进的叶片冷却技术是提高燃气轮机进口初温的有效措施。通过分析三菱M701F燃气轮机叶片冷却技术的冷却原理和运行方式,为燃气轮机的安全高效运行提供参考。     

八面河油田面12区综合调整措施及效果分析

八面河油田面12区为断块稠油油藏,油层出砂、渗透率差异大。为了解决产量递减快、注采井网不完善、储量控制程度低、油井高含水等问题,采取加强地质综合研究、钻调整井和侧钻井、进行注水井注氮调剖等措施,有效地改善了油藏开发效果。     

三次样条插值在变径内腔重建中的应用

结合变径内腔容积参数检测的特殊要求,在分析了内径-进深容积检测方法的基础上,提出了一种基于三次样条的内腔直径参数插值和基于插值后函数的内腔三维内表面高精度重建方法.该方法是在对内腔容积内径和进深间接测量的基础上,对测量中测头沿轴间歇移动时各进深直径值应用三次样条函数进行数值插值,通过建立M关系三对角方程组,并用"追赶法"实现插值函数稳定收敛求解,从而获得内径函数曲线的光滑高精度表达式,然后以插值后的内径函数曲线为母线进行内腔内表面的三维空间容积重建.实验和仿真结果证明:该方法能够克服直接累加和传统的分段低次线性插值方法由于函数本身的特性,在各次间歇测量点处产生的衔接不光滑性,满足了变径内腔内表面容积重建中的视觉需求;同时在不增加计算量的前提下使得插值后容积的测量精度得到了提高,且满足2‰测量误差的要求.     

一种新型桥梁信息采集与处理系统的设计

基于ICETEK-DM642-IDK-M及BenQ M22通信模块设计了桥梁信息采集、传输与处理系统.将GPRS通信技术运用于桥梁检测远程数据传输,克服了传统方法的缺点,更好地实现了桥梁检测数据远程实时传输和处理.     

Theoretical studies on kinetics,mechanism and thermochemistry of gas-phase reactions of HFE-449mec-f with OH radicals and Cl atom

A theoretical study on the mechanism and kinetics of the gas phase reactions of CF₃CHFCF₂OCH₂CF₃ (HFE-449mec-f) with the OH radicals and Cl atom have been performed using meta-hybrid modern density functional M06-2X using 6-31+G(d,p) basis set. Two conformers have been identified for CF₃CHFCF₂OCH₂CF₃ and the most stable one is considered for detailed study. Reaction profiles for OH-initiated hydrogen abstraction are modeled including the formation of pre-reactive and post-reactive complexes at entrance and exit channels. Our calculations reveal that hydrogen abstraction from the CH₂ group is thermodynamically and kinetically more facile than that from the CHF group. Using group-balanced isodesmic reactions, the standard enthalpies of formation for HFE-449mecf and radicals generated by hydrogen abstraction, are also reported. The calculated bond dissociation energies for CH bonds are in good agreement with experimental results. The rate constants of the two reactions are determined for the first time in a wide temperature range of 250–450 K. The calculated rate constant values are found to be 9.10 × 10⁻¹⁵ and 4.77 × 10⁻¹⁷ cm³ molecule⁻¹ s⁻¹ for reactions with OH radicals and Cl atom, respectively. At 298 K, the total calculated rate coefficient for reactions with OH radical is in good agreement with the experimental results. The atmospheric life time of HFE-449mec-f is estimated to be 0.287 years.     

基于Cortex-M3的便携式POS系统设计

针对目前嵌入式收款机系统在功能和性价比方面存在不足的问题,介绍了一种基于Cortex-M3芯片的嵌入式收款机系统。该系统功能全面、性能良好、界面完善、具有故障分析和机器自检功能。运行结果表明,该系统实现了预期目标。     

M2M技术在钢铁连铸设备MRO协作平台中的应用

自动、实时、准确、详细地获取钢铁连铸设备的信息,是钢铁连铸设备生产线维修、维护和大修MRO协作平台对设备故障预测的关键。针对此平台的需求构建了基于M2M技术的远程数据采集系统。它不仅能够为钢铁企业提供新的数据源,而且能够在一定程度上改进企业的生产和维修流程。     

Global Exponential Stability Analysis of Discrete‐Time Genetic Regulatory Networks with Time Delays

This paper focuses on the study of global robust exponential stability of discrete‐time genetic regulatory networks (GRNs) with time‐invariant/time‐varying delays and parameter uncertainties. Many existing results on this problem are based on the linear matrix inequality (LMI) approach, which needs to verify whether there exists a feasible solution of a set of LMIs. Along with the increase in the number of genes, dimensions of LMIs will increase accordingly, which will lead to a large amount of calculation. Based on M‐matrix theory, sufficient conditions ensuring the global robust exponential stability of a class of discrete‐time GRNs with time‐invariant/time‐varying delays and parameter uncertainties are presented. These given conditions are to check whether a constructed constant matrix is a nonsingular M‐matrix. Simulation results of several examples are given to demonstrate the validity of the proposed method.     

地学e-Science发展的回顾与展望

自 e-Science 提出之后的近 20 年间,地学 e-Science 在计算、网络和存储等信息技术的推动下,业已形成了基于数据、模型、计算、可视化分析和协同工作的地学研究框架,已经成为推动地学研究方法变革的驱动器。本文梳理和归纳了地学 e-Science 的发展过程和一些典型应用,总结了地学e-Science 的发展趋势,提出了简化的基于 3M 平台（Monitoring（监测平台）、Modeling（模型平台）、Manipulating（操作平台））的地学 e-Science 架构。从地学 e-Science 发展趋势上看,建立基于数据产生、采集、传输、管理的联合观测系统,形成完善的监测平台是地学 e-Science 的基础。建立数据分析、制备、同化和模型构建、集成与模拟的模型平台是地学 e-Science 的核心。建立基于高性能计算、可视化分析和协同工作环境的操作平台是地学 e-Science 研究的基本环境。