GIS气体高压开关在阳煤五矿变电站的应用

针对阳煤五矿广场变电站的高压开关老化问题,为了保证安全性,采用了GIS气体的高压绝缘开关进行了改造。在改造后,变电站的安全性得到了显著提高,设备运行可以节省成本200多万元。     

New titanium (III) phosphite structure and its application as anode for lithium ion batteries

A new titanium (III) phosphite Ti₂(HPO₃)₃, has been synthesized under hydrothermal conditions. The solid-state structure of this material was solved using single-crystal X-ray diffraction. The anionic inorganic skeleton has a three-dimensional structure, which is built up by TiO₆ octahedral units linked together via bridging HPO₃ pseudo pyramids, giving rise to tunnels along the three crystallographic axes. This new compound displays a high thermal stability limit of 625 °C. IR and Raman spectroscopies show the vibrational modes of the (HPO₃)²⁻oxoanions. Electrochemical activity of this phase toward reversible insertion of Li ion was studied for the first time by galvanostatic charge-discharge measurements, an insertion host for reversible accommodation of Li⁺ was observed.     

Impact of applied cell voltage on the performance of a microbial electrolysis cell fully catalysed by microorganisms

The effect of the operating voltage on the performance of a microbial electrolysis cell (MEC) equipped with both a bioanode and a biocathode for hydrogen production is reported. Chronoamperometry tests ranged between 0.3 and 2.0 V were carried out after both bioelectrodes were developed. A maximum current density up to 1.6 A m⁻² was recorded at 1.0 V with hydrogen production rate of nearly 6.0 ± 1.5 L m⁻² cathode day⁻¹. Trace amounts of methane, acetone and formate were detected in cathode's headspace and catholyte which followed the same trend as hydrogen production rate. Meanwhile substrate consumption in anolyte also followed the trend of hydrogen production and current density changes. The bioanode could utilise up to 95% of acetate in the tested voltage ranges, however, at a cell voltage of 2.0 V the bioanode's activity stopped due to oxygen evolution from water hydrolysis. Cyclic voltammograms revealed that the bioanode activity was vital to maintain the functionality of the whole system. The biocathode relied on the bioanode to maintain its potential during the hydrogen evolution. The overall energy efficiency recovered from both bioanode and external power in terms of hydrogen production at the cathode was determined as 29.4 ± 9.0%, within which substrate oxidation contributed up to nearly 1/3 of the total energy marking the importance of bioanode recovering energy from wastewater to reduce the external power supply.     

AlF3-modified LiCoPO4 for an advanced cathode towards high energy lithium-ion battery

Surface-interface reaction between the electrode and electrolyte plays a key role in lithium-ion storage properties, especially for high voltage cathode such as LiCoPO₄ and Ni-riched cathode. Generally, surface modification is an effective method to improve the electrochemical performance of electrode materials. Herein, in order to revise the LiCoPO₄ cathode with desirable properties, uniform AlF₃-modified LiCoPO₄ (LiCoPO₄@AlF₃) cathode materials in nano-sized distribution are synthesized. XRD result indicates that there is no structural transformation observed after AlF₃ coating. TEM characterization and XPS analysis reveal that the surface of LiCoPO₄ particle is coated by a nano-sized uniform AlF₃ layer. Further, the electrochemical results indicate that AlF₃ layer significantly improves the cycling and rate performances of LiCoPO₄ cathode within the voltage range of 3.0–5.0 V. After a series of optimization, 4 mol% AlF₃-coated LiCoPO₄ material exhibits the best properties including an initial discharge capacity of 159 mA h g^?1 at 0.1 C with 91% capacity retention after 50 cycles, especially a discharge capacity of 90 mA h g^?1 can be obtained at 1 C rate. CV curves indicate that the polarization of cathode is reduced by AlF₃ layer and EIS curves reveal that AlF₃ layer relieves the increase of resistance to facilitate Li-ion transfer at the interface between electrode and electrolyte during the cycling process. The enhanced electrochemical performances are attributed to that the AlF₃ layer can stabilize the interface between the cathode and electrolyte, form steady SEI film and suppress the electrolyte continuous decomposition at 5 V high voltages. This feasible strategy and novel characteristics of LiCoPO₄@AlF₃ could promise the prospective applications in the stat-art of special lithium-ion battery with high energy and/or power density.     

The vibration and pull-in mechanism of two coupled elastically restrained beams assembly subjected to electrostatic force

ABSTRACT

The novel model of the coupled beam-type electrodes with elastic roots, subjected to the AC and DC voltages is constructed. The exact critical pull-in voltage of the two coupled elastically restrained beams with size effect is presented. The analytical method of the general system subjected to the AC and DC voltages simultaneously is presented. The characteristic mechanism of coupled vibration is investigated.     

Effect of Moving Speed of Charged Metallic Spherical Electrode on Electrostatic Discharge

In this investigation, the nature of the electrostatic discharge (ESD) that occurs when a charged object moves toward a stationary grounded object is experimentally clarified. The spark lengths, discharge currents, and induced voltages in a magnetic probe were measured when a charged metallic spherical electrode connected to a 422 pF capacitor approached a stationary grounded object, which was the current target, for different moving speeds of the charged metallic spherical electrode in a range of 1 mm/s to 100 mm/s. The charge voltages of the capacitor were +6.5 kV and +10 kV. Based on the results, the average gap length shortened with the speed of the spherical electrode. The average peak values of the discharge current and the induced voltage were likely to increase with the speed of the spherical electrode. The average rise times of the discharge current and the induced voltage were likely to drop with the speed of the spherical electrode. The relation between the spark length and the discharge current due to the ESD can be explained qualitatively by using an equation derived from the spark resistance formula proposed by Rompe and Weizel.     

一种计算空间异面高压线间最短距离的方法

在电力工程建设、运行、管理中,需要遵循许多行业规范,尤其是高压线间的间距,关系到电网运行的安全与否。对于一些容易判断两线间最短距离的高压线,如平行的高压线等,可以方便的求出其最短距离,但是,在遇到一些不易判断出两线间最短距离位置的高压线时,需要通过一定的方法求出两高压线间的最短距离,以判断是否符合规范要求,确保电网的安全运行。本文提出一种利用Mathematica软件计算空间异面高压线间最短距离的方法。     

Voltage reference architectures for low-supply-voltage low-power applications

This paper presents a voltage reference generator architecture and two different realizations of it that have been fabricated within a standard 0.18 μm CMOS technology. The architecture takes the advantage of utilizing a sampled-data amplifier (SDA) to optimize the power consumption. The circuits achieve output voltages on the order of 190 mV with temperature coefficients of 43 ppm/°C and 52.5 ppm/°C over the temperature range of 0 to 120°C without any trimming with a 0.8 V single supply. The power consumptions of the circuits are less then 500 nW while occupying an area of 0.2 mm² and 0.08 mm², respectively.     

Study on the basic capacitance–voltage characteristics of organic molecular semiconductors

Capacitance–voltage (C–V) characteristics of organic molecular semiconductors attracted much research interest recently, but no convincing physical mechanism has been established so far. In this work, the C–V characteristics of pentacene-based devices have been systematically investigated at various frequencies. Only one peak occurs when the measuring frequency is less than 3 kHz or greater than 8 kHz. While within the frequency range between the two, two C–V peaks are observed with quite different dependence on temperature, which suggests that the origins of these two C–V peaks are respectively mobile holes and trapped carriers. This conclusion is also experimentally validated with the C–V characteristics of intentionally doped devices.     

建筑电气工程中低压配电系统的安装与调试

低压配电系统对建筑电气工程是非常重要的，本文对其安装做论述，针对各种建筑物对配电的要求，对系统做合理的调试，最终实现建筑实体安全用电，同时也确保低压配电系统的稳定性。