消除成品表面裂纹的轧制关系分析

针对方坯或板坯原始表面存在一定深度的裂纹,讨论了轧前加热烧损量对坯料裂纹深度的影响,通过对不同断面形状坯料原始裂纹深度与轧制变形关系的理论计算,编制相应的计算程序,确定了方坯或板坯原存最大裂纹深度为T0max时,消除或减轻其相应成品表面裂纹的轧制关系分析。     

HID灯及其电子镇流器

该文介绍了高强度气体放电(HID)灯的各项性能指标与应用领域,并重点对其配套用电子镇流器的结构、原理,以及对比磁回路式镇流器所具备的特点予以阐述。     

Optimal and self‐tuning weighted measurement fusion Kalman filters and their asymptotic global optimality

For the multisensor linear discrete time‐invariant stochastic systems with unknown noise variances, using the correlation method, the information fusion noise variance estimators with consistency are given by taking the average of the local noise variance estimators. Substituting them into two optimal weighted measurement fusion steady‐state Kalman filters, two new self‐tuning weighted measurement fusion Kalman filters with a self‐tuning Riccati equation are presented. By the dynamic variance error system analysis (DVESA) method, it is rigorously proved that the self‐tuning Riccati equation converges to the steady‐state optimal Riccati equation. Further, by the dynamic error system analysis (DESA) method, it is proved that the steady‐state optimal and self‐tuning Kalman fusers converge to the global optimal centralized Kalman fuser, so that they have the asymptotic global optimality. Compared with the centralized Kalman fuser, they can significantly reduce the computational burden. A simulation example for the target tracking systems shows their effectiveness. Copyright © 2010 John Wiley & Sons, Ltd.     

钒在冶金中的应用及研究进展

介绍了钒在铸铁、合金钢、合金结构钢、合金工具钢及不锈钢等钢铁行业,以及其在有色冶金等领城中的应用现状和研究发展趋势,指出钒在冶金行业及国民生产和国防中的重要意义。     

厦门技师学院建筑中水的应用研究分析

本文是以完成设计并已竣工使用的厦门技师学院的中水回用系统为实例,用节能减排绿色环保的理念在校区的规划设计和水资源的回用中,寻求一种完善的可行的非传统性水资源回用的途径。     

监理企业从事项目管理与监理一体化的探索

分析了我国项目管理与监理业务的趋同与背离,指出了工程监理与项目管理的高度关联和趋同性,并用具体实例,证实了监理企业从事项目管理和监理一体化服务是顺应市场需求的必然趋势。     

县域城乡规划空间管制的途径研究

本文结合县情实际,依据新颁布的《城乡规划法》,探索提出了构建覆盖县域、层次清晰、目标明确、管理有序、执法有据、可操作性强的完整的城乡规划体系的途径。     

异极性永磁偏置径向磁轴承的参数设计与实现

为了克服现有异极性永磁偏置径向磁轴承参数设计的不足,对一种异极性永磁偏置径向磁轴承进行了研究,分析其结构和工作原理。以其为对象提出了一种根据二维有限元仿真结果构建等效磁路,以满足承载力所需的偏置磁场与控制磁场的磁通量为基本目标;并以软磁材料不饱和为约束条件,结合等效磁路,推导出永磁材料和定转子结构的参数设计方法;设计了径向悬浮力400N的原理样机,进行了三维仿真分析和实验验证。结果表明:提出的参数设计方法合理,利用该方法设计的异极性永磁偏置径向磁轴承悬浮性能优良,为其他型永磁偏置磁轴承的研究奠定了基础。     

On delay constrained CAC scheme and scheduling policy for CBR traffic in IEEE 802.11e wireless LANs

CBR (constant bit rate) traffic is expected to be an important traffic source in wireless networks. Such sources usually have stringent jitter or delay requirements and in many cases they should be delivered exactly as they were generated. In this paper, we propose a strictly guaranteed QoS (quality‐of‐service) provisioning CAC (call admission control) scheme with a polling‐based scheduling policy for CBR traffic in IEEE 802.11e wireless LANs. Under such a scheme, the proposed transmit‐permission policy for HCCA (HCF controlled channel access) method can forecast the maximum suffered delay for each packet and derive sufficient conditions so that all the CBR sources satisfy their time constraints to provide deterministic QoS guarantees. A simple analytical model is carried out to estimate the average queueing delay of the proposed scheme. In addition to theoretical analysis, simulations are conducted to validate its promising performance. Our simulation results show that the proposed scheme maintains a high throughput with respect to the whole range of system load. Copyright © 2009 John Wiley & Sons, Ltd.