Thermal-stability improvement of a sulfur-passivated InGaP/InGaAs/GaAs HFET

The temperature-dependent characteristics of an InGaP/InGaAs/GaAs heterostructure field-effect transistor (HFET), using the (NH/sub 4/)/sub 2/S/sub x/ solution to form the InGaP surface passivation, are studied and demonstrated. The sulfur-passivated device shows significantly improved dc and RF performances over a wide temperature range (300-510 K). With a 1/spl times/100-/spl mu/m/sup 2/ gate-dimension HFET by (NH/sub 4/)/sub 2/S/sub x/ treatment, the considerably improved thermal stability over dc performances including lower temperature variation coefficients on the turn-on voltage (-1.23 mV/K), the gate-drain breakdown voltage (-0.05 mV/K), the gate leakage current (1.04 /spl mu/A/mm/spl middot/K), the threshold voltage (-1.139 mV/K), and the drain-saturation-current operating regimes (-3.11/spl times/10/sup -4//K) are obtained as the temperature is increased from 300 to 510 K. In addition, for RF characteristics, the sulfur-passivated device also shows a low degradation rate on drain-saturation-current operating regimes (-3.29/spl times/10/sup -4//K) as the temperature is increased from 300 to 400 K. These advantages provide the promise for high-speed high-frequency high-temperature electronics applications.     

风柴储生物质独立微电网系统的优化规划设计

对某偏远原住民社区现有供电系统、负荷及自然资源情况进行了分析统计,提出一种包含风柴储生物质的独立微电网解决方案,以替换现有的柴油供电系统。根据各分布式电源的技术特性,提出一种改进型负荷跟随控制策略,以柴油发电机组和生物质发电系统分别跟随系统内不同时间尺度下的净负荷波动,储能系统主要起系统稳定控制作用,可显著提高可再生能源渗透率,减少柴油消耗量,并能优化储能系统的容量配置和运行工况。以系统20年寿命周期净现值费用与污染物排放最小为优化目标,采用改进型非劣排序遗传算法(NSGA-Ⅱ),开展了系统方案的综合优化设计,结果表明了优化设计方案的可行性。     

Fabrication of SiO/sub 2/ microlenses on silicone rubber using a vacuum-ultraviolet F/sub 2/ laser

SiO/sub 2/ microlenses are fabricated on a silicone rubber surface. The silicone surface irradiated by an F/sub 2/ laser beam swells and is modified to SiO/sub 2/ by means of photochemical reaction. When the surface is irradiated by 6000-12000 shot laser pulses, it becomes smooth and spherical. By altering the number of pulses, it is possible to alter the microlenses' focal lengths within the range of 120-170 /spl mu/m.     

Economic Analysis of Hybrid Wind/PV/Diesel/ESS System on a Large Oil Tanker

Due to the global concern on the increasing amount of fossil energy consumed by traditional ships, the application of renewable energy into a ship power system provides a new solution to improve the energy efficiency and to reduce the greenhouse gas emissions. This study proposes a stand-alone power system on a large oil tanker including wind generation system, photovoltaic generation system, the diesel generator, and the energy storage system (ESS). Unlike on land, the wind generation on the shipboard not only relies on the natural wind speed but also the ship's course and speed. The installation of the wind turbines on the board is optimally designed, which takes the relative speed into account. In order to mitigate the intermittence of the renewable energy generation, a lead–acid battery serves as the ESS to enhance the stability of the ship power system, and the size is optimized by the multi-objective particle swarm optimization to minimize the whole system cost and CO₂ emissions. Additionally, variations of the ship loads are considered with respect to the different operational conditions. Various cases are compared in detail to demonstrate the applicability of the proposed algorithm.     

Evaluation of SiO/sub 2/ antifuse in a 3D-OTP memory

We have evaluated an antifuse technology used in a novel three-dimensional one-time-programmable (3D-OTP) nonvolatile solid-state memory. The 3D-OTP memory uses deposited polysilicon antifuse sandwiches to build its memory cells. The polysilicon based SiO/sub 2/ antifuse show different breakdown characteristics compared to conventional traditional gate oxides. Long-term storage tests show that this 3D-OTP solid-state memory not only can be a general purpose ROM, but also can be an ideal media for archiving.     

一种光伏电池-蓄电池-超级电容器复合电源系统设计

常用的蓄电池电源功率特性差且不能从环境中获取能量补充。本文介绍了一种由光伏电池、蓄电池和超级电容器组成的复合电源系统,提出了开放性、可重组的复合电源动态体系结构,采用相互等效的思想使复合电源控制系统的设计得到了简化。通过建证复合电源仿真模型,对复合电源存移动机器人上的应用进行了仿真,最后采用设计的移动机器人复合电源系统样机进行了实验。仿真结果和实验结果均说明了本义复合电源设计方法的可行性,也验征了移动机器人采用复合电源的优越性．     

Interruption capability of CF/sub 3/I Gas as a substitution candidate for SF/sub 6/ gas

We studied the interruption performance of CF₃I gas because its environmental effect is smaller than that of SF₆ gas with a model arc-extinguishing chamber. First, we measured the arc time constant and arc power loss coefficient using Mayr's equation. Comparing CF₃I with other gases, the arc time constants are SF₆3I2< H₂2. The arc power loss coefficient is H₂>SF₆ >CO₂>Air>N₂ >CF₃I. Next, we evaluated the short line fault (SLF) interruption capability by measuring the di/dt-dv/dt characteristic. Consequently, the SLF interruption performance of pure CF₃I was about 0.9 times that of SF₆. However, CF₃I application to gas insulated switchgear (GIS) and gas circuit breakers (GCB) is difficult because the liquefying temperature of the gas is high. Therefore, we adopted a countermeasure to obtain a lower liquefying temperature mixing CF₃I with CO₂. The result showed that the SLF interruption performance of the mixture approximated that of pure CF₃I when the ratio of CF₃ I exceeds 20%     

Analysis of a double-stator induction machine used for a variable-speed/constant-frequency small-scale hydro/wind electric power generator

A polyphase/single-phase rotary induction machine with double-stator windings, one fixed and the other able to be manually adjusted and positioned to match the mechanical and electrical power when used as a generator or a motor, is analysed and the advantages and disadvantages of such a hydro/wind generator are discussed. The rotor of the machine is normally in the form of a squirrel cage. The machine can feed power to the grid without an interface network. Optimal coupling to the prime mover when used as a generator or to the load when used as a motor is also derived from the analysis. This machine is also called an isosynchronous machine.     

Toepler's spark law in a GIS with compressed SF/sub 6/-N/sub 2/ mixture

This paper deals with the experimental measurements and analysis of the formative time lags to breakdown and an estimation of the Toepler's constant for gas gaps, under the application of 50 Hz AC voltage. The experiments were carried out in a 145 kV gas insulated system (GIS) bus duct with pure N/sub 2/, pure SF/sub 6/ and SF/sub 6/-N/sub 2/ mixture as insulating media. The formative time lags to breakdown in the gas gaps were measured using a fast response capacitive sensor. Toepler's spark law has been used to explain the breakdown phenomenon in the GIS and the values of Toepler's constant (k/sub t/), which gives an estimation of the formative time lags, were determined. Results show that the formative time lags vary inversely with gas pressure and the gas mixture concentrations for two gaps studied (0.46 mm and 0.61 mm). In the case of another gap (0.20 mm), the variation in the formative time lags with pressure as well as SE, concentration in the mixture has been found to be negligibly small between gas mixtures, although significant variation can be seen between pure SF/sub 6/ and pure N/sub 2/. Toepler's constant, k/sub t/, increases with gas pressure as well as SF/sub 6/ concentration in the mixture for the gaps studied. Hence, k/sub t/ is a function of the gas pressure and the concentrations of SF/sub 6/ in the gas mixture for the above-mentioned gaps.     

包含电动汽车的风/光/储微电网经济性分析

电动汽车在接入微电网时具有双重角色：充电时可看做负载;同时在电动汽车电池有足够电量的情况下,可以对微电网负载进行供电。文中针对电动汽车能量的双向流动性,提出了包含风、光、储、电动汽车等的微电网经济调度策略和模型,分析了电动汽车的加入对微电网经济性的影响。仿真结果表明：电动汽车的加入不仅可以节约微电网中静态储能设备的投资...     

流水线模数转换器设计

设计了一款14位、125MS/s流水线模数转换器(ADC)。通过前端采样/保持电路(SHA)消除对输入信号采样的孔径误差,采用4位结构的首级转换电路提高ADC线性性能,设计了带输入缓冲的栅压自举开关以缓解首级转换电路输入采样开关中自举电容对SHA的负载效应,流水线ADC级间通过逐级按比例缩减策略使功耗得到节省。该设计采用0.18μm 1P5MCMOS工艺,ADC版图面积2.3 mm×1.4 mm。Spectre后仿真结果显示,采样频率125 MHz、输入信号在接近Nyquist频率(61MHz)处时信号噪声畸变比(SNDR)和无杂散动态范围(SFDR)可分别达到75.7 dB和85.9 dB。在1.8V电源电压下,ADC核心部分功耗为263 mW。     

Buck DC/DC变换器在星载开关电源中的应用

介绍了一款可用于星载开关电源的Buck DC/DC变换器。为满足星载开关电源的需要,相对于传统的BuckDC/DC变换器,该变换器在消浪涌电路、启动电路、驱动电路、过流保护电路的设计上做了一些改进,重点分析了其工作原理,并给出了相关设计公式。该变换器转换效率高,可广泛应用于星载开关电源。     

Life cycle CO2 emissions of a photovoltaic/wind/diesel generating system

A photovoltaic/wind/diesel generating system with a battery (PWD system) is discussed from the viewpoint of total CO₂ gas emissions during system lifetime. The total emissions are the sum of the emissions occurring at manufacturing and operating. First, the manufacturing CO₂ emissions of the photovoltaic generator and the wind turbine generator are calculated by “the process analysis method.” This method considers the material used in each generator, its weight and its CO₂ emission rate. On the other hand, the manufacturing CO₂ emissions of the diesel generator and the battery are calculated using “the interindustry (input‐output) table.” Second, the PWD system is operated on a computer so that the fuel consumption of the diesel generator is a minimum assuming that hourly series data of electric load, insolation intensity, wind speed, and air temperature are known during the year. And CO₂ emissions occurring at system operation are obtained from the annual fuel consumption of the diesel generator. The results show that CO₂ total emissions of the PWD system are lower than those of the conventional diesel generator system. The CO₂ total emissions reach a minimum when the photovoltaic/wind generating ratio is 50/50. The CO₂ emissions of manufacturing decrease with increasing of the wind generating ratio from 100/0 to 0/100. The CO₂ total emissions decrease as the natural energy ratio increases. It is, however, saturated to about 60% when the ratio is more than 60%. And the CO₂ total emissions increase with increasing of the battery capacity. It is concluded that the PWD system plays an important role in decreasing considerably the CO₂ total emissions while the total system cost is high under the present price circumstances. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 14–23, 2002     

400 t/h炉水膜除尘器改造为电除尘器的实践

综述天生港发电厂9号炉除尘器改造的必要性,改造的主要特点、施工组织原则及经验教训;介绍了改造后的运行、测试、评价、效益情况.     

Design of LC/sub p/C/sub s/ resonant inverters as a power source for HID lamp ballast applications

This paper presents a new criterion for the design of resonant inverters for driving high-intensity-discharge (HID) lamps. The proposed converter behaves almost as a power source, for a wide load range, regardless of the lamp aging. In order to achieve good repeatability, the analysis of lamp power sensitivity regarding the tolerance of the circuit components is carried out. The design is validated with experimental results and a statistical simulation by the Monte Carlo method.     

Intentionally inserted oxygen depleted (Ba/sub 0.5/Sr/sub 0.5/)TiO/sub 3/ layers as a model of DC-electrical degradation

The relative dielectric constant versus voltage (/spl epsiv//sub r/-V) characteristics and the current density versus electric field (J-E) characteristics of (Ba/sub 0.5/Sr/sub 0.5/)TiO/sub 3/ films, which have intentionally inserted oxygen depleted layers near the bottom electrodes, were investigated as a model of dc-electrical degradation phenomena. Our investigation demonstrated that the intentionally inserted oxygen depleted layer is the cause of the tunneling conduction.     

Robust output-feedback H/sub /spl infin// control with a nonlinear observer for a two-mass system

In this paper, a positioning control of a nonlinear elastically coupled two-mass system is presented. Structures of two-mass systems can often be found, e.g., in robotics or machine tools. The contained mechanical parts, like gears and shafts, can lead to limit cycles and stick-slip effects. In order to avoid the unwanted effects an H/sub /spl infin// control design is used for the system. Parameter uncertainties and elastic torsion are also taken into account in the control synthesis. If the measurability is limited, so that only the system output can be measured, a nonlinear observer is used. The standard output-feedback H/sub /spl infin// control structure needs some basic changes for this nonlinear observer. The result is an H/sub /spl infin// control, which can handle the nonlinear system, even if only the system output can be measured. The control shows good dynamics, robustness, and can handle disturbances. Measured results are shown in this paper.     

基于多分区自适应改进果蝇算法的风光燃储微电网协调控制策略

为了使微电网控制系统中PI控制器的参数能够更好地适应可再生能源的随机性和波动性,提出了基于自适应步长的四分区多策略果蝇优化算法(fruit fly optimization algorithm, FOA)对PI参数进行实时优化。首先,以风光燃储微电网不同微源控制系统中的变换器为控制对象,建立微电网整体控制系统模型,基于此模型实时调整PI参数。然后,根据不同果蝇个体的适应度值将果蝇种群分为4个区,同时考虑4个区果蝇收敛性以及多样性的差异,设计不同的自适应更新策略。最后,采用所提算法对各微源控制过程中的PI参数进行寻优,与其他3种智能算法进行对比,验证了所提算法的可行性和优越性。仿真结果表明,所提算法可以使系统变换器响应速度更快,输出更加稳定。     

Gate-stack optimization of a vertically stacked nanosheet FET for digital/analog/RF applications

Journal of Computational Electronics - Nanosheet field effect transistors (NS-FET) are a most promising candidate for next-generation semiconductor devices for sub-7-nm technology nodes. This work...     

35 t/h锅炉的燃烧调整

提出了35t h锅炉燃烧调整重点是以各风室的配风调节为主,配合适当的炉排速度和煤层厚度,解决炉膛出口温度和排烟温度过高的问题,通过实践收到了较好的效果。