平板闸阀调节性能

介绍了平板闸阀结构特点、密封原理以及平板闸阀功能延伸——流量调节的原理、控制及应用。     

Determination of Membrane Protein Fouling by UV Spectroscopy and Electrochemical Impedance Spectroscopy

UV spectroscopy and electrochemical impedance spectroscopy were used to investigate the properties and performances of ultrafiltration membranes fabricated with different polymers. Membrane performances were studied by means of permeability and bovine serum albumin filtration. UV spectroscopy results showed that bovine serum albumin rejection was lowest in polyvinylidene fluoride membranes, whereas it was highest in polysulfone membranes. Electrochemical impedance spectroscopy data revealed that after bovine serum albumin filtration, resistance of the membranes was increased though double layer capacitances were decreased. Performance data of UV spectroscopy and electrochemical impedance spectroscopy were in correlation with each other. This study demonstrated that electrochemical impedance spectroscopy can be successfully used in filtration membrane studies.     

Stability influence factors analysis and construction of a deep beam anchorage structure in roadway roof

Deep beam anchorage structures based on spatial distribution analysis of the cable prestressed field have been proposed for roadway roof support. Stability and other factors that influence deep beam structures are studied in this paper using mechanical calculations, numerical analysis and field measurements. A mechanical model of deep beam structure subjected to multiple loading is established, including analysis of roof support in the return airway of S1203 working face in the Yuwu coal mine, China. The expression of maximum shear stress in the deep beam structure is deduced according to the stress superposition criterion. It is found that the primary factors affecting deep beam structure stability are deep beam thickness, cable pre-tension and cable spacing. The variation of maximum shear stress distribution and prestressed field diffusion effects according to various factors are analyzed using Matlabòand FLAC3D~(TM) software, and practical support parameters of the S1203 return airway roof are determined.According to the observations of rock pressure, there is no evidence of roof separation, and the maximum values of roof subsidence and convergence of wall rock are 72 and 48 mm, respectively. The results show that the proposed roof support design with a deep beam structure is feasible and achieves effective control of the roadway roof.     

交叉极化比对平板天线动中通收发系统性能的影响

交叉极化比是平板天线卫星动中通系统设计和加工的产物,它是衡量系统性能的一项重要参数。针对交叉极化比导致的极化误差,重点研究了交叉极化比对平板天线卫星动中通信号发射和接收系统的影响。通过理论推导和实际测试,结果表明不合理的交叉极化比会导致较大的极化误差,降低发射系统的发射效率,减小接收系统信噪比,导致系统性能恶化。为减小交叉极化的影响,建议等效口径0.6 m的平板天线卫星动中通的交叉极化比指标不小于30 dB。     

一款采用有源电感的增益可调且平坦的超宽带低噪声放大器

采用有源电感,设计了一款增益可调且平坦的超宽带低噪声放大器(FTG UWB-LNA)。在输入级,采用具有新型偏置电路和RLC反馈的共基-共射放大器来实现良好的宽带输入阻抗匹配;在放大级,采用由新型有源电感与达林顿结构构成的组合电路,来实现增益的可调性、平坦化和幅度提升。在输出级,采用电阻并联和电流镜偏置的共集放大器,来实现良好的输出阻抗匹配。基于WIN 0.2μm GaAs HBT工艺库,对FTG UWB-LNA进行验证,结果表明：在1-6GHz频带内,增益(S21)可以在21.16dB-23.9dB之间调谐,最佳增益平坦度达到±0.65dB;输入回波损耗(S11)小于-10dB;输出回波损耗(S22)小于-12dB;噪声系数(NF)小于4.08dB;在4V的工作电压下,静态功耗小于33mW。     

基于Verilog的模拟前端时序的实现方法

针对如何高精度、高速实现模拟前端时序的问题,提出了一种用于平板探测器的模拟前端时序的Verilog实现方法。Verilog语言的编程整体上采用模块化设计,主要包含电荷采集模块、数据读出模块和计数器模块。利用锁相环技术设置各模块不同的时钟信号,通过编写有限状态机和改进型计数器实现各模块的时序。仿真结果表明,该编程方法满足了时序高精度实现的需求,具有运行速度快、灵活性高等特点,达到了预期效果。     

大型屋面SP板滑移安装技术在工程中的应用

结合天津轻工业学院学生活动中心工程，对大型屋面SP预应力空心板滑移安装技术的工艺原理、施工技术、质量要求作了叙述。并对该技术的效益进行分析。     

具有发展前途的节能型屋面──倒置式屋面

本文通过倒置式屋面的论述，指出了该屋面在考虑屋面防水技术的同时，把屋面的保温隔热技术放到首位。这无论从建筑节能或是改善屋面的防水功能都是非常有益的。     

装饰性钢筋混凝土波瓦斜屋面防水技术

通过工程实践及实例调研 ,分析造成斜屋面渗漏的原因 ,提出了建筑设计、施工管理、材料使用等方面的防水技术 ,以供设计和施工时参考。     

楼层结构布置探讨

对楼层结构布置的基本原则、基本楼盖体系进行了论述。分析比较了几种基本的楼盖型式如交梁楼盖、井字楼盖、无梁楼盖等的优点，并提出了在楼盖布置时的基本思路。介绍了应考虑的各种影响因素、基本布置方法、使布置楼层结构时做到有章可循，合理经济。