稳定转台摩擦参数的测量及其对稳定精度的影响

提出一种测量由力矩电机驱动的稳定转台摩擦参数的方法.通过对转台自由减速过程速度曲线的拟合,以及电机启动过程电流的测量,可以得到最大静摩擦力矩、库仑摩擦力矩、粘滞摩擦系数和转动惯量.建立了稳定转台摩擦的仿真模型.针对一个单轴稳定转台进行的仿真和实验结果表明,在扰动换向时产生的稳定误差尖峰由扰动换向时的阶跃摩擦干扰力矩产生.仿真获得了和实验一致的精度结果.对进一步提高稳定精度的方法进行了分析.     

大坳拦河坝除险加固工程帷幕灌浆工艺试验研究

大坳拦河坝除险加固帷幕灌浆工程采用两种灌浆工艺进行对比试验.根据试验结果,采用"打管法自下而上"的灌浆工艺,取得了良好的效果,解决了传统灌浆工艺在该种地层中效率低、效果不明显的工程问题,为类似灌浆工程取得了良好的经验.     

光催化反应器中UV/Fenton光催化降解敌百虫农药废水的研究

在光催化反应器中,采用UV/Fenton光催化氧化技术,通过单因素分析实验及正交实验,对影响敌百虫农药废水的光催化降解过程中各因子进行分析及优化,研究结果表明:敌百虫有机磷农药光催化氧化降解率和COD去除率在A2B2C3D3及A3B2C3D3两种条件下都达到85%以上。当最适工艺条件控制为H2O2浓度7 mmol/L、Fe2 /H2O2比值1∶5,光照强度2000μw/cm2,pH为3,光照时间为90 min时,其中COD去除率、有机磷降解率分别为86.8%、89.9%以上,这表明UV/Fenton光催化氧化降解对敌百虫农药的降解具有较为显著的效果,为将来的应用奠定基础。     

基于硅烷化预处理的AZ91D镁合金超疏水表面的喷涂法制备

为提高镁合金的耐蚀性,推动镁资源的利用,以静态接触角、结合力、耐蚀性为主要技术指标,开发出镁合金表面超疏水化2步喷涂法处理技术.最佳涂料配方:2.0 g/L CNTs,1.0 g/L SiC,40.0 mL/L TEOS,0.2mL/L FAS,乙醇作溶剂.最佳涂装工艺:对基材以KH560水解液作为粘结剂并控制其体积/...     

某机场候机楼静力弹塑性分析

对某高安全等级、大柱距机场候机楼的结构形式给予介绍。为保证结构在罕遇地震下不倒,结构设计时在常规分析的基础上采用了静力弹塑性分析方法进行罕遇地震作用下的抗震分析。     

硬质聚氨酯泡沫在城市集中供热管道上的应用

介绍了城市集中供热管道用硬质聚氨酯泡沫的笥能和组合原料的工艺参数，并对保温管道的3种生产工艺如手工浇注法，一步法连续生产及二步法生产工艺进行了介绍了比较，给出了直埋供热管道保温层厚度的理论计算公式。     

A novel and efficient procedure for the preparation of 4,4′-bis(chloromethyl)biphenyl by chloromethylation of biphenyl catalyzed by PEG1000-DAIL under homogeneous catalysis in aqueous media

As described in this article, 4,4′-bis(chloromethyl)biphenyl was obtained in 85% excellent yield by chloromethylation of biphenyl catalyzed by the recyclable temperature-dependant phase-separation system that comprised the dicationic acidic ionic liquid PEG₁₀₀₀-DAIL and methylcyclohexane under homogeneous catalysis in aqueous media. Compared to other synthetic methods, the novel method not only enhanced the yield, but also made the operating units easy workup. The mechanism of chloromethylation reaction and the process of catalysis in the thermoregulated ionic liquid bi-phase system were proposed.     

碳五分离先进工艺的开发研究

在结合常规碳五分离工艺缺点及碳五热二聚特性的基础上,开发了在异戊二烯(IP)与环戊二烯(CPD)分离之后进行热二聚的后热二聚碳五分离新工艺,IP与CPD分离的关键为IP分离塔与CPD回收塔的组合。结果表明:后热二聚碳五分离新工艺具有更高的产品收率、更好的产品质量等诸多优点。     

高效回收镍盐化工污泥制取硫酸镍技术工艺分析

对镍盐化工污泥中镍的浸出条件进行了分析和考察,对浸出液中沉铁和沉镍的p H值进行了系统的分析;采用水洗工艺对粗产品中氢氧化镍杂质的去除效果进行分析,最终采用加酸溶解和蒸发结晶的方式制取硫酸镍产物。     

The Harmonic Analysis of RMP Coil Power Supply in EAST TOKAMAK

In EAST TOKAMAK, resonant magnetic perturbation (RMP) coils, which are powered by RMP coil power supply (PS), are set to research edge localized mode, resistive wall mode and error field correction. In order to meet the requirements of fast response and output voltage ripple proposed by physical experimenters, the structure of multiple modules using cascaded carrier phase-shifted PWM H-bridges is adopted, which enhances the equal switch-frequency of the PS and improves the quality of output voltage. In the paper, theoretical calculation applying Fourier analysis is given to analyze its harmonics. Both simulation results on Matlab and test results of output voltage ripple show that the RMP coil PS can meet the requirements.