微粒混凝土受拉性能研究

本文采用弯折和劈裂试验研究了微粒混凝土的受拉性能，并与普通混凝土进行对比。试验结果表明，微粒混凝土的抗拉强度高于普通混凝土．     

稀土双掺杂锰氧化物La0.5Dy0.2Sr0.3MnO3的磁性质

采用固相反应法制备了La0.5Dy0.2sr0.3MnO3样品,通过M-T曲线、M-H曲线、ESR曲线研究了样品的磁性质.结果表明:在rc处样品经历了顺磁到铁磁的转变;当r相似文献   

脉冲电流法测量变压器局部放电的频带选择

为研究变压器局部放电测量的频带问题,通过模拟试验测量了放电信号。信号功率谱密度的分析表明, 典型窄脉冲放电信号能量主要集中在≤10MHz。测量系统带宽对放电信号幅值影响的研究表明,带宽≥12MHz后对信号幅值无明显改善,带宽可根据需要选为8～20MHz。     

Enhancement of room-temperature magnetoresistance in La<Subscript>0.6</Subscript>Dy<Subscript>0.1</Subscript>Sr<Subscript>0.3</Subscript>MnO<Subscript>3</Subscript>/Ag<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>

The samples of La0.6Dy0.1Sr0.3MnO3/(Ag2O)x/2(x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, 0.25, and 0.30) were prepared by using the solid-state reaction method.Their magnetic property, transport behavior, transport mechanism and magnetoresistance effect were studied through the measurements of magnetization-temperature(M-T) curves, ρ-T curves and the fitting of ρ-T curves.The results indicated that Ag could take part in the reaction when the doping amount is small.However, when the doping amount is compar...     

烯丙基聚烷氧基环氧醚的制备及其性能

针对烯丙基聚烷氧基环氧醚中存在催化剂和钾钠离子含量高,导致制备的三元共聚嵌段硅油反应活性差的问题,研究了在无相转移催化剂的条件下制备烯丙基聚烷氧基环氧醚的方法,表征了产物的结构,分析了制备条件对产物pH值与环氧指数的影响;以其为原料制备了三元共聚嵌段硅油,并对棉织物进行柔软整理,分析了整理后织物的亲水性、手感及物理力学...     

Degradation location study of proton exchange membrane at open circuit operation

In order to investigate the location of the radical-initiated membrane degradation at open circuit operation, ceria (CeO₂) nanoparticles are firstly placed at different locations of the membranes to scavenge free radicals generated there. Scanning electron microscopy (SEM) is used to characterize cross-sectional morphology of membrane before and after the open circuit voltage (OCV) test. OCV decay rate is used as an indicator of membrane degradation rate. Composite membranes with CeO₂ nanoparticles facing anode or cathode show improved membrane durability than that of plain membrane in terms of OCV decay rate and cross-sectional morphology. CeO₂-Nafion composite membrane with the same thickness is subsequently proposed and it obtains the best durability. It is concluded that the chemical degradation at open circuit operation occurs at both sides of anode and cathode.     

开卷过程钢卷内部应力及张力优化技术

针对带钢开卷工序存在的松卷与层间滑移缺陷,考虑开卷机组设备与工艺的特点,通过理论研究与现场试验,建立了钢卷开卷过程中内部应力的分布模型,实现了对开卷过程钢卷内部应力分布的预报。在分析松卷与层间滑移缺陷产生机理的基础上,采用开卷层滑因子来定量描述松卷与层间滑移缺陷程度,结合钢卷开卷过程中的内部应力分布模型,开发了钢卷开卷过程中开卷张力的综合优化设定技术,达到了综合防控开卷过程中钢卷松卷与层间滑移缺陷的目的。     

(1-x)La0.7Ca0.3MnO3/xAg磁电阻的温度稳定性

用固相反应法将Ag引入La0.7Ca0.3MnO3颗粒表面,形成(1-x)La0.7Ca0.3MnO3/xAg(x=0.00,0.10,0.20,0.25,0.30,0.35)。通过XRD谱、扫描电子显微镜(SEM)照片及SEM能谱(EDS)、ρ-T曲线、ρ-T拟合曲线、MR-T曲线,研究电输运性质及MR温度稳定性。结果表明:随复Ag量增大,电阻率急剧下降,高复Ag(x≥0.3)的电阻率比低复Ag(x≤0.10)的电阻率下降2个数量级;发现x=0.00,0.10用ρ-T2公式拟合比较合理,是单磁子散射作用;x=0.20,0.25用ρ-T2.5公式拟合比较合理,是自旋波散射作用;x=0.30,0.35,分别在97,93 K以上用ρ-T4.5公式拟合比较合理,说明是电子-磁子散射作用;所有复Ag样品,在250～20 K温区MR表现出很好的温度稳性,特别是x=0.10的样品,在220～150 K温区MR保持(13.8±0.2)%。提出磁电阻稳定性的机制:Ag与钙钛矿颗粒形成电输运二元通道,钙钛矿颗粒通道产生的低场磁电阻与Ag通道产生的正常磁电阻共同作用,产生MR温度稳定性。     

Numerical Analysis of Electromagneto-Mechanical Coupling Dynamic Response of a Typical Tokomak Structure

In an effort to simulate the dynamic behavior of a non-ferromagnetic conducting structure with consideration of the magnetic damping effect,a finite element code is developed,which is based on the reduced vector potential (Ar) method,the step-by-step integration algorithm and a time-partitioned strategy.An additional term is introduced to the conventional governing equations of eddy current problems to take into account the velocity-induced electric field corresponding to the magnetic damping effect.The TEAM-16 benchmark problem is simulated using the proposed method in conjunction with the commercial code ANSYS.The simulation results indicate that the proposed method has better simulation accuracy,especially in the presence of a high-intensity external magnetic field.     

低浓度二甲醚生产废水的处理与回用

采用串联自循环活性污泥法+混凝沉淀+过滤+ClO2消毒工艺处理低浓度二甲醚生产废水,工艺运行稳定,操作维护简便,出水达到《工业循环冷却水处理设计规范》(GB 50050-2007)再生水水质指标,全部用于循环冷却水补水,具有良好的经济效益和环境效益.