1pF的数显电容计

用CMOS门电路、1 0 0kHz石英晶体、单稳态电路及计数 /译码器 ,制作了测量精度可达 1

流型对电容含水率计响应的影响

根据集流型流体电容含水率计的测量原理，按照模拟井实验结果，分析了流型对集流型流体电容含水率计响应的影响。在油水两相的情况下，电容含水率计环形测量空间内流型同样可以分为乳状流、泡沫流、段塞流和泡状流。乳状流时，总电容值小，含水率计响应相对于含水率和流量的变化率也小；泡沫流时，含水率计响应相对于含水率和流量的变化率较大；段塞流时，含水率计响应相对于含水率和流量的变化率很大；泡状流时，总电容值大，而含水率计响应相对于含水率和流量的变化率较低。

组合式电容含水率计的理论仿真及实验研究

介绍了一种新型的、可用于测量低产液水平井产液剖面含水率的组合式电容含水率计。给出了电容传感器的结构,分析了其测量原理,建立了数学模型,并用ANSYS软件对其数学模型进行了二维电场仿真。开展了室内静态实验,实验结果验证了理论分析的正确性。应用所设计的样机在多相流动态实验装置上进行了动态机理性实验,实验证明,组合式电容含水率计能够测量低产液下分层流,所设计的仪器在流量3~60 m3/d、含水率0~100%范围内有较好的分辨率,仪器的重复性好。

电容薄膜真空计校准装置的研制

介绍电容薄膜真空计校准装置的研制过程,采用静态膨胀法原理,其测量范围为(1×10^(-1)~1×10~4)Pa,相对扩展不确定度为(0.22%~0.06%)(k=2)。装置体积比采用原位法进行测试,各体积比相对标准不确定度为0.02%。

电容式持水率(含水率)计的调试与刻度

基于电容式持水率(含水率)计的基本原理,结合生产测井工程实践,文章简要探讨了电容式持水率(含水率)在制造过程中的调试方法。

新型数字电容表的研究

本文重点介绍新型数字电容表的工作原理及实际电路的设计方法。

MEMS加速度计嵌入式批量自动化测试系统设计

针对MEMS传感器人工测试、筛选存在的工作效率低、易出错等缺点,设计了一种MEMS电容式加速度计嵌入式自动化测试系统。系统主要由嵌入式多通道数据采集模块及上位机组成,两者通过USB接口进行通信。为提高测试效率,嵌入式数据采集模块采用微控制器控制4片菊花链方式级联的ADS1278,实现32通道模拟输出的同步采样。经测试,各通道有效分辨率均优于21 bits,满足系统设计指标要求。应用虚拟仪器技术设计了应用软件。实测结果表明该系统可大大提高MEMS传感器测试、筛选的效率。

一种角度计数字化实现方法

研究了乌兰韦伯测向系统中电容角度计听觉测向的数字化处理方法。分析了数字化处理过程中影响听觉效果的原因，为了获得类似电容角度计测向时平滑的听觉效果，采用对圆阵采样序列进行内插处理的方式，解决了听觉测向时和波束与差波束幅度突变的问题；在内插过程中进行了去混叠滤波处理，减弱了因混叠造成的副瓣升高对听觉效果的影响；数字化处理可灵活选择参与合成的阵元数，改善听觉效果。仿真试验验证了该方法的有效性。

EDLC charging performance for microgrid applications

In order to review storage performance of the electric double layer capacitor （EDLC） in microgrid applications, charging time and storage efficiency issues are mainly studied aiming at three different charging modes, including the constant voltage charging mode （CVCM）, the constant current charging mode （CCCM） and the constant power charging mode （CPCM）, based on the practical EDLC product. Numerical calculation methods are presented for different charging modes, and the charging efficiency is also reviewed with strict mathematical deductions, which is validated to be accurate enough and applicable through a simple case with the PV/EDLC system illustration. Finally, trade-off problems between charging time and energy loss are also studied. Research results show that the CPCM is more suitable for microgrid networks compared with the traditional constant-voltage and constant-current charging modes. The hybrid charging method is recommended to save energy and keep high efficiency relatively at the same time. However, how to manage the combination percentage of different charging modes in a reasonable way should be dealt with according to the practical requirements.

Battery Management System with State ofCharge Indicator for Electric Vehicles

Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. battery, the state of charge indicator for lead-acid battery was developed by means of an algorithm based on combination of ampere-hour, Peukert's equation and open-voltage method with the compensation of temperature,aging,self- discharging,etc..Results The BMS based on this method can attain an accurate surplus capa- city whose error is less than 5% in static experiments.It is proved by experiments that the BMS is reliable and can give the driver an accurate surplus capacity,precisely monitor the individual battery modules as the same time,even detect and warn the problems early,and so on. Conclusion A BMS can make the energy of the storage batteries used efficiently, develop the batteries cycle life,and increase the driving distance of EVs.

An iterative computation method for interpreting and extending an analytical battery model

Battery models are of great importance to develop portable computing systems,for whether the design of low power hardware architecture or the design of battery-aware scheduling policies.In this paper,we present a physically justified iterative computing method to illustrate the discharge,recovery and charge process of Li/Li-ion batteries.The discharge and recovery processes correspond well to an existing accurate analytical battery model:R-V-W's analytical model,and thus interpret this model algorithmically.Our method can also extend R-V-W's model easily to accommodate the charge process.The work will help the system designers to grasp the characteristics of R-V-W's battery model and also,enable to predict the battery behavior in the charge process in a uniform way as the discharge process and the recovery process.Experiments are performed to show the ac-curacy of the extended model by comparing the predicted charge times with those derived from the DUALFOIL simulations.Various profiles with different combinations of battery modes were tested.The experimental results show that the extended battery model preserves high accuracy in predicting the charge behavior.

Optimization Design of Silicon Micro - capacitive Accelerometer with PWM Technique

The property of silicon micro-capacitive accelerometer is analyzed and discussed by establishing the model of the sensor,to lay a basis for optimization design of sensor system structure. Discussed issues include the static modeling and dynamic behavior of the two commonly used structures,i.e., double-cantilever supported and four-beam supported structures, and also the measurement range of these devices.

Networks, Topology and Interaction Principle Implemented in the Kron＇s Method

This paper present electrical networks, with topological modelisations, generalized cross talked functions implemented in a Kron＇s formalism; Coupling functions are called chords and give a powerful extension to the method. Applied in electromagnetic compatibility, it has proven its efficiency in time computation and accuracy. The paper review the Kron＇s formalism, a mathematical modelisation of currents by tensorial analysis and topologie, the string principles, and an application, at the end, we propose power-chopper modeling.

The research of feet pressing energy collection and utilization device --based on piezoelectric ceramics

After people or vehicles press, piezoelectric ceramics can send a weak and unstable alternating current. According to this characteristic, we made feet pressing energy collection and utilization device based on piezoelectric ceramics. The two parts of this device includes energy storage and utilization. In terms of storage, the energy collection module, can deposit AC sent by piezoelectric ceramics in the super capacitor after rectification. In terms of utilization of energy, the device achieve a variety of usage： through the USB interface, it can supply power for different equipments, replace the mobile station of train stations and realize the function of saving the electricity as the night corridor induction lamp, combined with vibration module design and programmable timer. The whole structure is supported by an acrylic plate, which saves cost and have good durability. This device implements the storage and usage of idle feet pressing energy. In conclusion, it is helpful to provide a new idea for people＇ s low carbon lives and has a quite broad application prospect.

Operational program for proper capacity of electric bus charging station in Expo 2010

In the paper,an operational program of electric bus charging station is proposed,which is special for "The Construction Project for Expo 2010 Temporary Electric Bus Charging Station".Based on the quick-change mode,a vehicle operating schedule model has been established to meet the capacity of transport.Then,according to the quantity of passengers and utilization of batteries,a calculative method of parameters,such as the number of spare batteries and bus departure rules,has been provided.Furthermore,optimal simulation software designed for operating process of the charging station has been identified incorporating actual running data from electric buses and monitoring system of the charging station,and the rationality of the design is verified in the preliminary commissioning and the official operation.

Fundamental and Technical Challenges for a Compatible Design Scheme of Oxyfuel Combustion Technology

Oxyfuel combustion with carbon capture and sequestration （CCS） is a carbon-reduction technology for use in large-scale coal-fired power plants. Significant progress has been achieved in the research and development of this technology during its scaling up from 0.4 MWth to 3 MWth and 35 aWth by the combined efforts of universities and industries in China. A prefeasibility study on a 200 MWe large-scale demonstration has progressed well, and is ready for implementation. The overall research development and demonstration （RD＆D） roadmap for oxyfuel combustion in China has become a critical component of the global RD＆D roadmap for oxyfuel combustion. An air combustion/oxyfuel combustion compatible design philosophy was developed during the RD＆D process. In this paper, we briefly address fundamental research and technology innovation efforts regarding several technical challenges, including combustion stability, heat transfer, system operation, mineral impurities, and corrosion. To further reduce the cost of carbon capture, in addition to the large-scale deployment of oxyfuel technology, increasing interest is anticipated in the novel and next- generation oxyfuel combustion technologies that are briefly introduced here, including a new oxygen-production concept and flameless oxyfuel combustion.

Thermo-mechanical analysis of an SI engine piston using different boundary condition treatments

Heat transfer of an SI engine's piston is calculated by employing three different methods based on resistor-capacitor model with the help of MATLAB code, and then the piston is thermo-mechanically analyzed using commercial ANSYS code. The results of three methods are compared to study their effects on the piston thermal behavior. It is shown that resistor-capacitor model with less number of equations and consequently less solution time, is an appropriate method for solving problems of engine piston heat transfer. In the second part, the thermal stresses due to non-uniform temperature distribution, and mechanical stresses due to mechanical loads are calculated. Finally, the temperature distributions as a thermal load along with mechanical loads are applied to the piston to determine the total stress distribution and critical fracture zones. It is found that the amount of thermal stresses is considerable.

Design of Capacitor Bank in Parallel to Photovoltaic Power Plant

The purpose of the paper is to develop a solution for application of PV （photovoltaic） generators in MV （medium voltage） distribution system without unacceptable voltage changes due to drops of PV power output. The proposed solution includes operation of PV with predetermined leading power factor and addition of a capacitor bank in parallel to PV plant in order to compensate the reactive power absorbed by the PV inverters. The analytical expression of required power factor angle is derived. Adding a capacitor bank in parallel to PV power plant may pose a problem because of space limitations. The dimensions and cost of small MV capacitor banks depend significantly on the capacitor bank protection against internal faults. Application of the developed negative-sequence current difference method for the unbalance protection of the capacitor banks enables to achieve a compact and cost-reduced design of the banks connected in parallel to PV power plants. A real-world example of operation of the PV plant in parallel to the capacitor bank with the novel protection scheme is described.

High Frequency Transformers for DC/DC Converter Used in Solar PV System

This paper presents and investigates planar and coaxial high frequency power transformers used for DC/DC converters in a three phase photo voltaic （PV） power systems. The winding structure including a Faraday shield between the primary and secondary windings is designed to minimize eddy current losses, skin and proximity effects, and to reduce the leakage inductance, and the inter winding coupling capacitance. Finite Element Method is employed to analyze the magnetic flux and eddy current distributions. The two different kinds of prototype high frequency transformers are designed and tested. The simulation and experiment results are demonstrated and compared with non-shielded transformers. The shielded transformers have achieved the expected results with a relatively small coupling capacitance, compared with the conventional high frequency transformer. This shield decreases the inter-winding coupling capacitance Cps. The topology of this shield has to be such that it acts as a Faraday screen while avoiding eddy current generation.