Electrostatic discharge in semiconductor devices: protectiontechniques

Electrostatic discharges (ESDs) are everywhere-in our homes and businesses. Even the manufacturers of the electronics experience ESD failures in their factories. Electronic devices are sensitive to ESD. ESD results in failure of our computers, calculators, and car phones. There are ways to protect these sensitive components. This paper looks at ESD protection from a two-pronged approach: reducing the likelihood of having an ESD event and improving the robustness of the devices themselves. The first approach focuses on reducing the amount of charge that is developed and controlling the redistribution of any charges that are developed The second approach reviews ways to improve the circuit robustness by improving individual circuit elements and by adding additional elements for charge flow control and voltage clamping     

Analysis of the dielectric characteristics for polycrystalline Ba0.65Sr0.35TiO3 (II) – d.c. field dependence with a modified bias equation

The effect of direct-current (d.c.) biasing on the dielectric properties of Ba_0.65Sr_0.35TiO₃ (BST) with various grain sizes (0.87 μm to 5.43 μm) have been studied in the paraelectric state. The leakage current of BST samples is proportional to the biasing field. Specimens with larger grains exhibit higher leakage current under biasing. The bias equation used in the literature to predict the d.c. field dependence of permittivity is modified by introducing a bias exponent parameter β. This modified bias equation gives a better fit to the experimental results both in this study and in the literature. Similar trends of α (representing the distribution of relaxation times), β, and the variance of lattice distortion with grain sizes suggests that β is a material parameter. It is concluded that the temperature dependence, the frequency response and d.c. field effect for the dielectric characteristics of Ba_0.65Sr_0.35TiO₃ are all suppressed by the transition broadening.     

Failure mechanism and SPICE modeling of AlGaAs/GaAs HBT long-term current instability

The long-term current instability of AlGaAs/GaAs heterojunction bipolar transistor (HBT) is studied, and the physical mechanism contributing to such a behavior is investigated. Based on this, a model capable of predicting the HBT long-term current drift and mean time to failure (MTTF) is developed. In addition, such a model is implemented into SPICE circuit simulator, thus allowing the simulation of HBT circuits subjected to an electrical and thermal stress condition.     

Operation of integrated InGaAsP-InP optical amplifier-monitoringdetector with feedback control circuit

Monolithic integration of a monitoring detector with an optical amplifier simplifies the use of an amplifier in lightwave systems. The structure and performance are described of a monolithically integrated semiconductor optical amplifier with low-loss Y-branching waveguides and a monitoring p-i-n detector. The photocurrent of the integrated detector can be used as a single control parameter for amplifier output leveling, gain optimization, and in situ monitoring of facet antireflective coatings     

微量调速阀抗污染机理研究

本文分析和证明了微量调速阀在实现2-100ml/min 的微量控制时,其压力补偿器的结构性自动抗污染机理和阀具有的综合抗污染性能、其抗污染的机理和性能对设计和研究低污染敏感度的液压元件有实际的指导意义.     

虚拟仪器在1553B总线通信系统中的应用

现代航空通信系统大多建立MIL－STD－1553B多路传输数据总线通信网络基础上，应用于1553B总线通信系统中的虚拟仪器技术实时监控／回放总线信息，分析故障原因，协助验证总线设计。本文就虚拟仪器在1553B总线通信系统中的应用进行了初步探讨。     

A method to extract mobility degradation and total seriesresistance of fully-depleted SOI MOSFETs

Free-carrier mobility degradation in the channel and drain/source series resistance are two important parameters limiting the performance of MOS devices. In this paper, we present a method to extract these parameters from the drain current versus gate voltage characteristics of fully-depleted (FD) SOI MOSFETs operating in the saturation region. This method is developed based on an integration function which reduces errors associated with the extraction procedure and on the DC characteristics of MOS devices having several different channel lengths. Simulation results and measured data of FD SOI MOSFETs are used to test and verify the method developed     

The hemodynamics in intracranial aneurysm ruptured region with active contrast leakage during computed tomography angiography

Precise locations of rupture region under contrast agent leakage of five ruptured cerebral artery aneurysms during computed tomography angiography, which is to our knowledge for the first time, were successfully identified among 101 patients. These, together with numerical simulations based on the reconstructed aneurysmal models, were used to analyze hemodynamic parameters of aneurysms under different cardiac cyclic flow rates. For side wall type aneurysms, different inlet flow rates have mild influences on the shear stresses distributions. On the other hand, for branch type aneurysms, the predicted wall shear stress (WSS) correlates strongly with the increase of inlet vessel velocity. The mean and time averaged WSSes at rupture regions are found to be lower than those over the surface of the aneurysms. Also, the levels of the oscillatory shear index (OSI) are higher than the reported threshold value, supporting the assertion that high OSI correlates with rupture of the aneurysm. However, the present results also indicate that OSI level at the rupture region is relatively lower.     

Design of Self-Tuning PID Power System Stabilizers for Synchronous Generators

A new technique for the excitation control of a synchronous generator is presented in this paper. The proposed technique employs a self-tuning proportional-integral-derivative (PID) power system stabilizer in order to improve the dynamic performance of a synchronous machine under a wide range of operating condition. Digital simulation of a synchronous machine subject to a major disturbance of a three phase fault under different operating conditions is performed to demonstrate the effectiveness of the proposed controller. It is found that the self-tuning PID stabilizer can enhance both the transient stability and the dynamic performance of the synchronous machine.     

Heat transfer in a smooth-walled reciprocating anti-gravity open thermosyphon

This paper describes an experimental investigation of heat transfer in a smooth-walled reciprocating anti-gravity open thermosyphon with relevance to the ‘shaker’ cooling system for the pistons of marine propulsive diesel engines. A selection of experimental results illustrates the interactive effects of inertial, reciprocating and buoyancy forces on heat transfer. It is demonstrated that the gravitational and reciprocating buoyancy effects, respectively, improve heat transfer in the static and reciprocating anti-gravity open thermosyphon. The individual pulsating force effect impairs heat transfer in the axial region with 5 hydraulic diameter length measured from the entrance of thermosyphon (region I). In the vicinity of sealed end of reciprocating thermosyphon with one hydraulic diameter from the sealed surface (region II), the individual pulsating force effect improves heat transfer at low pulsating number range, over which range a subsequent heat transfer reduction in this axial region is followed. The synergistic effects of inertial force, reciprocating force and buoyancy interaction in the reciprocating anti-gravity open thermosyphon could, respectively, impede or improve the regional heat transfers in the axial regions I and II from the static references of zero-buoyancy. A set of empirical correlations, which is physically consistent, was developed that permits the individual and interactive effects of inertial, reciprocating and buoyancy forces on heat transfer to be evaluated.