High-voltage portable pulsed power supply fed by low voltage source

This article proposes a new structure of voltage multiplier for portable pulsed power applications. In this configuration, which is based on capacitor-diode voltage multiplier, the capacitors are charged by low AC input voltage and discharge through the load in series during pulse generation mode. The proposed topology is achieved by integrating of solid-state switches with conventional voltage multiplier, which can increase the low input voltage step by step and generate high-voltage high-frequency pulsed power across the load. After some discussion, simulations and experimental results are provided to verify the effectiveness of the proposed topology.     

利用高压热处理技术提高Bi-2223/Ag高温超导带材临界电流

提高临界电流密度(Jc)对促进Bi-2223/Ag高温超导带材的应用有着重要意义.在常压热处理条件下所制备的带材中存在大量的裂纹、孔洞和第二相颗粒等,这些因素都会对带材的超导连接性能产生破坏作用.我们成功建立了一套可用氧气氛的热等静压设备,工作气压和温度可同时达到15MPa和850°C.通过引入裂纹愈合热处理过程,我们成功对带材进行了高压热处理,所得样品中第二相颗粒和裂纹数量大幅度降低,77K、自场下的临界电流相比常压热处理样品提高了20%左右.     

Surface modification of pure titanium by pulsed electron beam

The microstructure, hardness and corrosion resistance of commercially pure Ti treated by low energy high current pulsed electron beam (LEHCPEB) have been investigated. The thin near-surface melted layer rapidly solidified into β and subsequently transformed into ultrafine α′ martensite. This has led to a drastic improvement of the corrosion properties and a significant increase (more than 60%) in hardness of the top surface.     

静电激励放大器的设计

静电激励放大器是电容传声器的性能测量、分析及生产过程中的检验不可缺少的设备。这里简要介绍一种这样设备的设计方案及电路设计，并进行了电路分析。     

Single‐run capillary electrophoresis method for the fast simultaneous determination of amoxicillin,clavulanate, and potassium

We report a new fast method for the simultaneous determination of amoxicillin, clavulanate, and potassium by capillary electrophoresis with capacitively coupled contactless conductivity detection. Samples containing potassium as the cation, and both amoxicillin and clavulanate as anions were determined simultaneously in a single run (in less than 45 s) using 10 mmol/L of both 2‐amino‐2‐hydroxymethyl‐propane‐1,3‐diol and 3‐{[2‐hydroxy‐1,1‐bis(hydroxymethyl)ethyl]amino}‐1‐propanesulfonic acid (pH 8.4) as the background electrolyte. Limits of detection were 25.0, 5.0, and 4.0 μmol/L for amoxicillin, clavulanate, and potassium, respectively. The proposed method is inexpensive, simple, fast (75 injections h⁻¹), environment friendly (minimal waste generation), and accurate (recovery values between 98 and 103%). The results obtained with the proposed method were statistically similar (95% confidence level) to those obtained by using high‐performance liquid chromatography (amoxicillin and clavulanate) and flame photometry (potassium).     

电脉冲沉积铝化物及铝化物-Y_2O_3涂层

采用电脉冲沉积技术在 2 0碳钢表面上获得了冶金结合的晶粒尺寸约为几十到几百纳米的铝化物和铝化物 弥散Y2 O3复合微晶涂层。60 0℃空气中氧化 10 0h的结果表明 ,电脉冲沉积获得的两种涂层均可显著地降低 2 0碳钢的氧化速率并提高氧化层的抗剥落性能。用AFM ,SEM ,EDS和XRD对铝化物涂层及氧化层进行了分析 ,并讨论了两种涂层提高抗氧化性能的作用机制     

生物可降解高吸水性非织造布的研制

用聚丙烯酸接枝淀粉浆液，在ＰＶＡ非织造布上形成吸水树脂，从而得到高吸水性非织造布。对接枝单体的比例、交联条件、浸轧量及非织造布规格等因素对高吸水非织造布吸水性能的影响进行了讨论了并测定了其生物降解性能。     

S波段直线对撞机中具有膜片涂层加速腔的高功率实验(英文)

加速管中的高次模（HOM）能导至累积束流崩溃，因此这些模式必须被抑制．在S波段直线对撞机中（SBLC），采用了在束流孔膜片上复盖适当的损耗材料的方式．HOM的Q值被减小了5倍，而基模的Q值几乎保持不变．3种材料被考虑，即：stainlesssteel，kanthal和galvedc为了对具有这种涂层的加速腔进行高功率测试，一个两腔的谐振器结构被设计．本文描述了高功率测试的原理，过程以及初步的结果．     

氟胺氰菊酯的定性定量分析

氟胺氰菊酯是一种用于蜜峰的高效杀螨剂。从20%商品氟胺氰菊酯粉剂中通过硅胶柱层板分离得到了96.6%的纯品并用FTIR和GC/MC进行定性量测定。采用GC/MS定量分析的方法，氟胺氰菊酯的浓度在0.05-10mg/L范围为线性响应，最低检测极限为 0.01mg/L。采用R（-）N-3，5-二硝基苯甲酰-苯基甘氨酸和长链烃的硅胶微粒手性柱，可成功地分离氟胺氰菊酯的二种旋光异构体，它们在商品氟胺氰菊酯中的比例近似为1：1。