A novel integrated silicon capacitive microphone-floating electrode“electret” microphone (FEEM)

A novel principle “electret” microphone, i.e., floating electrode electret microphone, is proposed and implemented in this study. Single-chip fabrication and corrugation technique are used in the design and fabrication of the microphone. The floating electrode is encapsulated by highly insulated materials to ensure that there is no electric-leakage passage between the floating electrode and the electrodes of the microphone. Net-free electronic charges (not “bonded” charges as in traditional electret) in the floating electrode can excite the electric field, which is similar to that of the traditional electret. The floating electrode can be easily charged by use of the “hot” electron technique, available using the avalanche breakdown of the p⁺-n junction. Therefore, the electret microphone is rechargeable, which can greatly increase the lifetime of the device. The preamplifier has been on-chip integrated in a junction-field-effect transistor (JFET) source-follower type with resistors by use of ion implantation. Electret charges are banded in a deep potential trap, thus, this microphone can operate at a high temperature (as high as 300°C) and has high stability and reliability. Experiments show that the prototype has a 3-mV/Pa sensitivity and a larger than 21-kHz frequency bandwidth in a 1 mm ×1-mm diaphragm area. Microphone performance can be further improved by optimized process and design. The fabrication is completely integrated-circuit (IC) compatible, hence, the microphone shows promise in integrated acoustic systems     

饮酒驾车的优化模型

本文通过分析啤酒中酒精在人体体内胃肠(含肝脏)与体液(含血液一)之间的交换机理,分别建立了在短时间内喝酒和长时间喝洒两种情况下,胃肠和体液(含血液)中的酒精含量的微分方程模型.对给出的数据,利用非线性最小二乘数据拟合及高斯-牛顿算法,确定了酒精含量以及酒精从胃肠进入血液的速度系数和酒精从血液渗透出体外的速度系数.继而,对不同喝酒方式下,血液中洒精浓度进行分析;该模型可以预测喝酒后任一时刻血液中的酒精浓度.对于第一问假设大李在第一次检查后半小时喝酒,由于体液中有残留的酒精,故第二次检查时酒精浓度为20.2448毫克/百毫升.     

Simulation Study of Aspects of the Classical Hydrogen Atom Interacting with Electromagnetic Radiation: Elliptical Orbits

The present study examines the behavior of a classical charged point particle in near-elliptic orbits about an infinitely massive and oppositely charged nucleus, while acted upon by applied electromagnetic radiation. As recently shown for near-circular orbits, and now extended here to the elliptical case, rather surprising nonlinear dynamical effects are readily produced for this simple system. A broad range of stability-like conditions can be achieved by applying radiation to this classical atom. A perfect balance condition is examined, which requires an infinite number of plane waves representing harmonics of the orbital motion. By applying a scale factor to this radiation, stability-like conditions are produced where periodic variations in semimajor and semiminor axes occur for extended periods of time, before orbital decay eventually takes over due to the effects of radiation reaction. This work is expected to lead to both practical suggestions on experimental ideas involving controlling ionization and stabilization conditions, as well as hopefully aiding in theoretical explorations of stochastic electrodynamics.     

ULTRA‐FINE TRACKING CONTROL ON PIEZOELECTRIC ACTUATED MOTION STAGE USING PIEZOELECTRIC HYSTERETIC MODEL

The tracking control accuracy of the piezoelectric actuator (PEA) is limited due to its inherent hysteresis nonlinearity. A new piezoelectric‐actuator model is synthesized based on two first‐order transfer systems in parallel with two tuned parameters determined from one experiment. Two open‐loop tracking controllers are implemented with the proposed model to compensate the hysteresis of linear positioning. Numerical simulations and experimental tests on the tracking of sinusoidal and triangular waveforms with signal frequencies ranging from 1Hz to 30 Hz are revisited and compared with the conventional Bouc‐Wen and Duhem models. Experimental results reveal that the RMS tracking error can be reduced to less than 2% of the maximum traveling distance without any feedback sensor. When a piezoelectric actuated on a two Degree‐Of‐Freedom (DOF) monolithic motion stage was employed, the RMS tracking error was 50 nm within the measured sensor accuracy.     

测量雷达天线座轴系精度分析

本文分析了影响测量雷达天线座轴系精度的一主要因素,为轴系设计提供参考。     

线阵CCD在安瓶三径在线自动检测分选系统中的应用

阐述了用线阵CCD检测系统通过变速扫描实现安瓶三径在线检测与控制的应用研究。文中用变速扫描方案，使在满足系统测量精度和高速的条件下，大大降低了对线阵CCD器件和扫描伺服系统性能的要求，使系统更具有实用价值。     

消失模铸造铸铁件水基涂料的研制

选用石英粉为耐火骨料，酸式磷酸盐为粘结剂，通过正交试验确定了铸铁件消失模水基涂料的最佳配比。经测试和生产验证，其性能良好，能很好地适应生产要求。     

用于空气净化的电除尘理论分析

论述了电除尘器用于工业除尘与空气净化时的差异,分析了电除尘器效率公式以及有效驱进速度等要点,讨论了电除尘器设计中的类比方法。     

计算机控制与检测气动换向阀试验台

介绍一种采用计算机控制与检测气动换向阀试验台的特点和测试系统设计。     

人工神经网络在交流传动控制中的应用

综述和分析了人工神经网络在交流传动控制中的应用 ,提出了有待解决的问题 ,对今后的发展趋势进行了展望。