一种用于导电油墨的特种铜粉制备研究

特种导电油墨是全印制电路技术开发与应用的关键之一。本文报道了利用硫酸铜、碳酸钠、抗坏血酸等为原料,通过固相反应获得纳米非球形铜粉方法。通过SEM、EDS分析表明,获得的产物为一种柱状的高纯铜粉,直径大约500nm,可以作为全印制电路技术用高性能特种油墨的开发。     

复杂环境中天线辐射方向图的分析

采用一致性几何绕射理论(UTD)研究了电大尺寸复杂平台中天线的辐射特性。以点源模型分析了天线受周围电磁环境影响后的辐射方向图,与自由空间方向图的对比说明了受影响后天线辐射特性的变化。与低频算法相比,本文算法有计算速度快、占用内存量很少的优点,可应用于工程中类似平台的多天线系统干扰分析。     

具有泡孔结构的聚合物导电复合电磁屏蔽材料的制备方法评述

如今急剧增加的各种通信系统和高频电子器件导致电磁干扰现象和电磁辐射污染问题日益突出.具有泡孔结构的聚合物导电复合材料不仅具有易加工、耐化学腐蚀和性能可调的优势,其泡孔结构还可以进一步赋予材料轻质的优势,同时增强电磁波在泡孔内部的多重散射/反射衰减以提升材料对电磁波的吸收,已经成为高性能电磁屏蔽材料的研究热点之一.本文综...     

Investigations of electrically driven liquid metal flows using an ultrasound Doppler flow mapping system

This paper presents a combined experimental and numerical study of the properties of a liquid metal flow inside a cylinder driven by the application of a strong electrical current. The interaction between the electric current running through the melt and the corresponding induced magnetic field produces so-called electro-vortex flows. We consider here a configuration of two parallel pencil electrodes immersed at the free surface. Velocity measurements were performed by means of the Ultrasound Doppler method. A linear array of 25 singular transducers was used to determine the two-dimensional pattern of the vertical flow component. Numerical simulations of the magnetohydrodynamic (MHD) problem were conducted to calculate the Lorentz force, the Joule heating and the induced melt flow. Experimental and numerical results reveal a complex three-dimensional flow structure of the liquid metal flow. In particular, two pronounced downward jets are formed below both electrodes. The flow structure appears to be symmetrical with respect to two vertical cross sections being perpendicular to each other and one of the two planes contains the electrodes. The comparison between the experimental data and the numerical results shows a very good agreement.     

The design,development and assessment of electrically heated gloves used for protecting cold extremities

Abstract

The design and development of electrically heated gloves for alleviating pain in vaso-spastic disorders, such as Raynaud's disease, is described. Clinical assessment of these conditions from the temperature patterns produced by infrared thermography is discussed. The effect of electrically heated gloves on tissue perfusion in individual patients can be assessed by thermography. A ‘hot’ stress test to determine the degree of vaso-spasticity using the gloves to provide a ‘hot challenge’ has been developed and is described.     

Photo-Doped Active Electrically Controlled Terahertz Modulator

We demonstrate an electric-controlled terahertz (THz) modulator which can be used to realize amplitude modulation of terahertz waves with slight photo-doping. The THz pulse transmission was efficiently...     

A New Methodology to Evaluate the Cure of Resin-Impregnated Paper for HPL

This paper presents a study on the curing conditions of several resin-impregnated papers and its impact on the performance of HPL (high-pressure decorative laminate). A new methodology for evaluating the bond strength development between the different layers of a HPL(overlay, decorative, and kraft papers) was developed using ABES (Automated Bonding Evaluation System) equipment. The proposed method can be applied to the study of the curing step of the different impregnated paper and the development of bonds between them (overlay paper on decorative paper, decorative paper on kraft paper, and kraft paper on kraft paper) trying to simulate the hot-pressing of an industrial HPL. This will permit to establish a more adapted temperature gradient in hot-press in order to achieve the same curing rate for all layers and provide a good final overall product quality.     

Effect of moisture content on curing kinetics of agglomerate cork

The curing process of Toluene 2,4-DiIsocyanate (TDI) pre-polymer with granulate cork is significantly affected by the cork moisture content since the reaction of isocyanate is highly sensitive to water. Two types of moisture are considered: the moisture contained inside the granulate cork, residual moisture, and the moisture intentionally sprayed over the granules of cork, added moisture. This study analyses the curing kinetics of TDI and granulate cork mixtures containing added moisture using Differential Scanning Calorimetry (DSC), and the reaction rate increase associated with the added moisture content (AMC). The underlying objective of this work is to reduce the time needed to obtain agglomerate cork stoppers through AMC increase.     

Effect of Nanoclay on the Mechanical,Thermal, and Water Absorption Properties of an UP-toughened Epoxy Network

Unsaturated polyester (UP)-toughened epoxy nanocomposites were prepared, and their effective mechanical and thermal properties were studied. Two types of organo-modified montmorillonite (OMMT) clays were used to prepare the nanocomposites. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis showed the formation of exfoliated silicate layers in the UP-toughened epoxy matrix. Mechanical tests revealed that nanocomposites (containing 1 wt% OMMT clay) showed an increase in tensile strength to 13.8%, flexural strength to 10%, and impact strength to 4% compared with an UP-toughened epoxy blend. The effect of different heating rates on the curing behavior of UP-toughened epoxy nanocomposites was investigated using non-isothermal differential scanning calorimetry. The data were interpreted using the Kissinger and Flynn–Wall–Ozawa models to find the curing reaction parameter. The water uptake behavior for nanocomposites increased with the addition of OMMTs. Scanning electron microscopy micrographs indicated morphological changes in the impact fractured samples of UP-toughened epoxy nanocomposites.