Au nanoparticles as a novel coating for solid-phase microextraction

A novel solid-phase microextraction fiber based on a stainless steel wire coated with Au nanoparticles was prepared and has been applied, coupled with gas chromatography, to the extraction of aromatic hydrophobic organic chemical pollutants in rainwater and soil extract. The solid-phase microextraction fiber exhibited excellent extraction efficiency and selectivity. Effects of extraction time, extraction temperature, ionic strength, stirring rate and desorption conditions were investigated and optimized. Single fiber repeatability and fiber-to-fiber reproducibility were less than 7.90% and 26.40%, respectively. The calibration curves were linear in a wide range for all analytes. Correlation coefficients ranged from 0.9941 to 0.9993. The as-established SPME-GC method was used successfully to two real natural samples. Recovery of analytes spiked at 10 μg L(-1) and 100 μg L(-1) ranged from 78.4% to 119.9% and the relative standard deviations were less than 11.3%.     

Z箍缩丝阵负载区域的似稳态磁场分布

 将负载区域的电流（丝阵电流、阴极板电流、阳极板电流和回流柱电流）离散成电流线或电流面等电流微元,根据毕奥-萨伐尔定律,计算所有电流微元在指定场点的磁场,再通过叠加给出该点的总磁场。研究结果发现:在丝阵外围区域,仅由丝阵电流所产生的磁场偏离无限长直导线磁场公式的值,但全部电流所产生的总磁场与公式给出的值很接近。同时,研究了不同负载结构参数下的磁场分布,结果表明：增加丝根数有助于减小单根丝表面的局部磁场,改善丝阵外围磁场分布的均匀性。     

Abrasive resistance of arc sprayed carbonitride alloying self-shielded coatings

Wear-resistant coatings were prepared on the surface of the Q235 low-carbon steel plate by HVAS with the carbonitride alloying self-shielded flux-cored wire. Detection and analysis on the microstructure and properties of the coatings were carried out by using scanning electron microscope, microhardness tester and wear tester. The forming, the wear resistance and its mechanism of the coatings were studied. The results show that the coatings have good forming, homogeneous microstructure and compact structure. The coatings have good hardness, the average microhardness value reaches 520 HV_0.1, and the highest value is up to about 560 HV_0.1. As a result, the coatings have good abrasive wear performance and adhesion strength.     

pcb电源布线设计-印制导线温升与导线宽度和负载电流的关系

本文阐述了PCB电源分配网络布线需要关注的几个方面,提供了量化设计的方法和工具.结合案例,介绍了电源通流能力可靠性设计的方法.     

Anisotropic transport properties of quantum dot arrays fabricated by the edge-defined nanowires

The anisotropic transport properties of quantum dot arrays fabricated by the nanoimprinted multilayer quantum wires have been investigated. The vertical transport characteristics are estimated by the carrier capture time from the electron reservoir to the low dimensional structures, which turned out to be longer than the spontaneous emission lifetime. The lateral transport characteristics are modeled after the quantum conductance between quantum dot arrays which are readily available from the miniband structures. The resulting lateral transport revealed that lateral quantum conductance can be minimized when the Fermi level is kept at the center of the miniband gap when the gap is larger than 4 kT.     

Ce-Pt-Pd/不锈钢丝网催化剂的制备与催化性能

采用阳极氧化技术在不锈钢丝网上自生长了一层结构致密的阳极氧化膜,并以此为载体,制备出一种高活性、高稳定性的负载型Ce-Pt-Pd催化剂.考察了该系列催化剂对甲苯、丙酮和乙酸乙酯的氧化活性,并用扫描电镜、X射线光电子能谱和程序升温氧化技术对催化剂进行了表征.结果表明,不锈钢丝网载体表面自生长的氧化物膜十分有利于活性组分的负载,制得的催化剂具有较高的催化燃烧有机化合物的活性和稳定性.     

OPGW温升上限的确定及其测量

影响OPGW温升上限的因素较多，本文简要分析了这些因素，并介绍了几种OPGW短路电流和温升的测量方法。     

自动检测系统在荧光灯绷丝机中的设计与应用

应用电气自动检测技术改进荧光灯绷丝机，完善工艺，节约成本，提高生产合格率。     

半导体量子器件

概述了半导体量子微结构中的量子效应，并介绍了谐振隧道器件，评述了新的量子微结构，如单电子隧道器件，电子波衍射晶体管和量子线量子箱激光器的开发，还讨论了量子微结构的尺寸要求和研究课题。