浅谈我国城市景观风貌规划的发展方向

随着我国的快速城市化,公众对城市景观风貌的需求日益提高。如何更好地利用城市资源,体现城市特色和科学规划管理,成为了当前城市景观风貌规划需要合理完善的主要任务。     

施工企业信息化建设的探讨与体会

综述了当前施工企业信息化建设的现状及建设中存在的普遍问题,有针对性的提出了信息化建设的相关对策。     

复杂条件下钢拱桥整体吊装技术

结合北京银帆·西雅图工程商业楼中央天井18m跨度钢拱桥安装,介绍了因施工环境限制,在安装时无法使用任何起重设备的情况下,利用周边已有条件和简单的起重工具(钢丝绳、卷扬机、滑轮等),安全进行钢拱桥整体运输和安装的方法.实践证明,该方法机动灵活,安全高效,非常适合本工程的特点.     

Influence of bearing damping on instability of asymmetric shafts, part IV: Effects of fluid-film bearings

The influence of fluid-film bearings on the parametric instability of asymmetric shafts is investigated. Since fluid-film bearings may have non-isotropic stiffness and damping, the system equations are time-varying coefficients in a rotating reference frame and the complete solution of transition curves includes coupled modes. Thus, the analytical modal method provided by our previous studies has been modified in this part for the determination of approximate solutions from a truncated Hill's determinant. In numerical examples, a plain cylindrical type and a tilting four-pad type are considered to estimate the effects of bearing parameters concerning static load, oil viscosity, and clearance on unstable regions.     

基于谐波相序特性的谐波电能提取技术研究

针对国内煤矿电力系统谐波污染日益严重的现状,提出一种将滤波电路与三相变压器串联,结合谐波相序特性提取电网谐波电能的方法,即滤波电路与三相变压器串联组成调谐电路,其谐波电流流入变压器一次侧,从变压器二次侧提取谐波电能。由于调谐电路中含有容性基波电流,要在变压器一次侧并联基波调谐电路,再将容性基波电流分流。重点对谐波提取电路进行了稳态特性分析,并利用Matlab进行仿真分析。仿真结果表明,该谐波提取电路实现了在不取用基波电能的情况下,提取电网谐波电能。     

PLC在恒压供水自动控制系统的应用

阐述了PLC与变频器的供水自动化控制系统的构成,泵组切换与恒压供水控制方法和系统保护功能的实现。随着变频调速技术的发展,变频恒压供水系统已经取代了传统供水方式,广泛应用于工矿企业和市政供水系统。     

含钒粘土矿两段浸出提钒工艺

采用碱浸预处理-酸浸提钒的两段浸出工艺从含钒粘土矿中浸出钒, 考察了碱浸预处理工序中NaOH用量和浸出时间、预处理后酸浸工序中H₂SO₄用量、浸出温度、浸出时间、液固比等因素对钒浸出率的影响。碱浸预处理能部分溶解Si、Al矿物, 从而破坏含钒矿物晶体结构, 为酸浸提钒时提高钒浸出率并降低酸耗创造条件。实验结果表明, 在95 ℃温度下用20%NaOH对矿样浸出24 h后, 酸浸工序中H₂SO₄用量30%, 温度95 ℃, 液固比1.5∶1, 浸出时间12 h, 钒浸取率达到了80%以上。     

Effect of thermo-mechanical processing on microstructure and creep properties of the foils of alloy 617

The effect of rolling and annealing on the microstructure and high temperature creep properties of alloy 617 were investigated. Two types of foil specimens with different thickness reductions were prepared by thermo-mechanical processing. Recrystallization and grain growth were readily observed at specimens annealed at 950 and 1100 °C. The uniform coarse grains increase resistance against creep deformation. The grain size effect in creep deformation was dominant up to 900 °C, while dynamic recrystallization effect became dominant at 1000 °C. Dynamic recrystallization was observed in all the creep deformed foils, even though some specimens had already been (statically) recrystallized during annealing. Steady state creep rates decreased with increasing annealing temperature in the less rolled foils. The apparent activation energy Q_app for the creep deformation increased from 271 to 361 kJ/mol as the annealing temperature increased from 950 to 1100 °C.     

The ceracon process for P/M technology: A review of recent developments

The Ceracon process, CERAmic CONsolidation, was originally developed in the mid 1970's to consolidate powder metals. The process has been successfully applied to near-net-shape production of oil drilling and other mechanical tools using conventional materials such as steel or tungsten carbide. The basic concept of the Ceracon process to consolidate powder material is still applicable in the preparation of fully dense forms, but there are a number of new applications for the Ceracon process which have emerged over the past few years. In this article, the latest developments in the Ceracon technology will be reviewed. These developments include the consolidation of oxide enclosed P/M materials such as environmentally sensitive superconducting powders, aluminum 6061 alloy and rapidly solidified Ti-48%A1 alloys.     

苏里格地区苏X井区盒8段储层粒度中值的计算及其应用

本文在研究苏里格地区石盒子组盒8段岩心分析粒度中值数据基础之上,结合测井资料提供的参数,建立了该区盒8储层粒度中值与自然伽马、密度以及声波时差之间的相关关系式,研究表明,该区盒8段储层粒度中值与自然伽马的一元二次回归关系式相关性最为显著,在利用回归关系式计算出盒8段粒度中值的基础之上,建立了该区盒8段储层的渗透率计算公式,并且取得了好的应用效果。