Stimadyn D全数字控制系统在中厚板厂主传动交流同步机上的应用

介绍ＳｉｍａｄｙｎＤ全数字控制系统在济钢中厚板厂粗轧机上的应用，实践证明，该系统能有效提高交流调速传动控制系统的设计、调试效率、运行可靠性及免维护水平。

Unified Degradation Model in Low Gate Voltage Range During Hot-Carrier Stressing of p-MOS Transistors

Hot carrier effects of p MOSFETs with different oxide thicknesses are studied in low gate voltage range.All electrical parameters follow a power law relationship with stress time,but degradation slope is dependent on gate voltage.For the devices with thicker oxides,saturated drain current degradation has a close relationship with the product of gate current and electron fluence.For small dimensional devices,saturated drain current degradation has a close relationship with the electron fluence.This degradation model is valid for p MOSFETs with 0 25μm channel length and different gate oxide thicknesses.

A Simple Model to Determine the Trends of Electric Field Enhanced Water Dissociation in a Bipolar Membrane

This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation process on a bipolar membrane based on the existence of a depletion layer and Onsager's theory. Particular attention was given to the influence of applied voltage on depletion thickness and the dissociation constant. The factors on the water splitting process, such as water diffusivity, water content, ion exchange capacity, temperature, relative permittivity, etc. Were adequately analysed based on the derived model equations and several suggestions were proposed for decreasing the applied voltage in practical operation. The water dissociation tests were conducted and compared with both the theoretical calculation and the measured current-voltage curves reported in the literature, which showed a very good prediction to practical current-voltage behavior of a bipolar membrane at high current densities when the splitting of water actually commenced.

Multi-Physics Modeling of Solid Oxide Fuel Cell Fueled by Methane and Analysis of Carbon Deposition

Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick＇s model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.

Bosonic Operator Realization of Hamiltonian for a Superconducting QuantumInterference Device

Based on the appropriate bosonic phase operator diagonalized in the entangled state representation we construct the Hamiltonian operator model for a superconducting quantum interference device. The current operator and voltage operator equations are derived.

Electrode Potential Explaining the Growth of Anodic Oxides

The formation mechanism of porous anodic oxides remains unclear till now.The classical field-assisted dissolution(FAD)theory cannot explain the relationship between the current curve and FAD reaction,and the influence of the electrode potential on anodization is rarely reported.The electrode potential theory,oxygen bubble model and the ionic current and electronic current theories were introduced to explain the growth of porous anodic oxides of three metals(Ti,Zr and Fe).Taking the anodization of Ti in aqueous solution containing 0.5wt% NH_(4)F as an example,the electrode potential was calculated,and the morphology of porous anodic oxides was investigated at low voltages.Results show that the growth of porous anodic oxides is determined by the ratio of the ionic current to the electronic current.During the anodization,metals are classified into two groups:one is easy to form the compact oxide layer,and the other is easy to induce oxygen releasing,thus forming oxygen bubbles.The electrolyte is also classified into two groups correspondingly:compact oxide layer-assisted electrolyte and releasing oxygen-assisted electrolyte.