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。     

Voltage Assisted Control of Spin-Transfer Nano-Oscillators

The spin-transfer nano-oscillator(STNO) has recently acquired a huge amount of research interest, due to its promising easy tunability along with the miniature size. The output frequency control of an STNO through magnetic field and current has been examined almost to its full extent; however, there are issues that still need to be addressed. Here, we propose a novel way of voltage control of the output frequency of an STNO, and alongside reducing its power requirement.     

自然循环窄矩形通道内过冷沸腾两相摩擦阻力特性

采用去离子水作为实验工质，在低压低流速自然循环工况下开展了单面加热可视化窄矩形通道内的过冷沸腾摩擦阻力特性实验研究。实验中测量了实验段内的压降数据，并通过高速摄影仪拍摄了窄矩形通道内的气液两相图像，提出了过冷沸腾条件下的两相摩擦压降的剥离计算方法。基于本实验中获得摩擦压降数据，对分别基于均相流模型和分液相模型的经典两相摩擦压降计算关系式进行了评估，实验结果表明：采用不同等效黏度计算方法的均相流模型计算结果比实验值明显偏小；而分相流模型中，Sun and Mishiba关系式和Tran关系式均能够较好地预测摩擦阻力，计算值与实验值的平均相对偏差在±15%以内。结合实验数据，以分相流模型方法为基础，考虑全液相Reynolds数、Martinelli参数和Laplace数的影响，获得了计算分液相折算系数的经验关系式，与实验数据符合较好, 平均相对误差在10%范围内。     

Solution-Processed Organic Solar Cells with High Open-Circuit Voltage of 1.3 V and Low Non-Radiative Voltage Loss of 0.16 V

Compared with inorganic or perovskite solar cells, the relatively large non-radiative recombination voltage losses (ΔV_non-rad) in organic solar cells (OSCs) limit the improvement of the open-circuit voltage (V_oc). Herein, OSCs are fabricated by adopting two pairs of D–π–A polymers (PBT1-C/PBT1-C-2Cl and PBDB-T/PBDB-T-2Cl) as electron donors and a wide-bandgap molecule BTA3 as the electron acceptor. In these blends, a charge-transfer state energy (E_CT) as high as 1.70–1.76 eV is achieved, leading to small energetic differences between the singlet excited states and charge-transfer states (ΔE_CT ≈ 0.1 eV). In addition, after introducing chlorine atoms into the π-bridge or the side chain of benzodithiophene (BDT) unit, electroluminescence external quantum efficiencies as high as 1.9 × 10⁻³ and 1.0 × 10⁻³ are realized in OSCs based on PBTI-C-2Cl and PBDB-T-2Cl, respectively. Their corresponding ΔV_non-rad are 0.16 and 0.17 V, which are lower than those of OSCs based on the analog polymers without a chlorine atom (0.21 and 0.24 V for PBT1-C and PBDB-T, respectively), resulting in high V_oc of 1.3 V. The ΔV_non-rad of 0.16 V and V_oc of 1.3 V achieved in PBT1-C-2Cl:BTA3 OSCs are thought to represent the best values for solution-processed OSCs reported in the literature so far.     

电压对电刷镀三价铬镀层性能的影响

在45钢表面电刷镀得到三价铬镀层,镀液组成和工艺条件为:Cr2(SO4)36H2O 0.4 mol/L,甲酸铵0.5 mol/L,氨基乙酸0.5 mol/L,H3BO30.6 mol/L,NaH2PO2 H2O 0.3 mol/L,pH=1.5,温度50°C,镀笔移动速率15 cm/s。研究了电压对镀铬层显微结构、表面粗糙度、厚度、显微硬度和耐磨性的影响。随电压增大,镀层厚度增大,显微硬度和耐磨性均先提高后降低。电压为14 V时,镀层的表面平整,粗糙度为2.387μm,显微硬度为602 HV,耐磨性最好。