A physical and scalable I-V model in BSIM3v3 for analog/digitalcircuit simulation

A new physical and continuous BSIM (Berkeley Short-Channel IGFET Model) I-V model in BSIM3v3 is presented for circuit simulation. Including the major physical effects in state-of-the art MOS devices, the model describes current characteristics from subthreshold to strong inversion as well as from the linear to the saturation operating regions with a single I-V expression, and guarantees the continuities of I_ds, conductances and their derivatives throughout all V_gs, V_ds, and T_bs, bias conditions. Compared with the previous BSIM models, the improved model continuity enhances the convergence property of the circuit simulators. Furthermore, the model accuracy has also been enhanced by including the dependencies of geometry and bias of parasitic series resistances, narrow width, bulk charge, and DIBL effects. The new model has the extensive built-in dependencies of important dimensional and processing parameters (e.g., channel length, width, gate oxide thickness, junction depth, substrate doping concentration, etc.). It allows users to accurately describe the MOSFET characteristics over a wide range of channel lengths and widths for various technologies, and is attractive for statistical modeling. The model has been implemented in the circuit simulators such as Spectre, Hspice, SmartSpice, Spice3e2, and so on     

提高激光三角法测量精度的新方法

激光三角法是一种几何测量的重要方法,目前已广泛用于测量位移和三维面形,但这测量系统的测量精度不高,一个主要的问题就是光源光强不稳定;本文提出用光学双稳装置来稳定激光光泊的光强,并用于测量金属板材,实验结果：将光学双稳装置用于激光三角法使系统的测量精度大大提高。     

AlGaInP-sapphire glue bonded light-emitting diodes

A novel method was proposed to glue an AlGaInP-GaAs light-emitting diode (LED) onto a transparent sapphire substrate. The absorbing GaAs was subsequently removed by selective wet etching. It was found that the emission efficiency could reach 401 m/W under 20-mA current injection for the 622-nm glue bonded (GB) AlGaInP-sapphire LED. It was also found that these GB LEDs are highly reliable, with small variations in operation voltage and luminescence intensity during the life test.     

Effects of information sharing on supply chain performance in electronic commerce

As businesses adopt electronic commerce, information exchange between business partners within a supply chain becomes more essential. Information exchange is often considered when companies implement the Extranet. This study aims to analyze the impact of various levels of information sharing including order, inventory, and demand information, which is based on transaction costs. This study further examines the effects on supply chain performance in electronic commerce. Specifically, the multiagent simulation system Swarm is employed to simulate and analyze the buyer-seller correlation in sharing information among business partners in supply chains. Our findings indicate that the more detailed information shared between firms, the lower the total cost, the higher the order fulfillment rate, and the shorter the order cycle time. In other words, information sharing may reduce the demand uncertainty that firms normally encounter. Firms that share information between trading partners tend to transact with a reduced number of suppliers. In sum, this work illustrates the effects of various levels of information sharing on supply chain performance in electronic commerce.     

Computation of full-vector modes for bending waveguide using cylindrical perfectly matched layers

A new full-vector approach to calculate leaky modes on three-dimensional bending waveguides is developed and demonstrated with the help of the cylindrical perfectly matched layer (CPML) numerical boundary conditions. By utilizing the complex coordinate stretching technique in the cylindrical system, a new set of full-vector wave equations for the bending waveguide structures are derived for the perfectly matched layer regions. Numerical solutions by the finite-difference schemes for the new wave equations are shown to yield highly accurate complex propagation constants (e.g., the bending-induced phase shifts and leakage losses) and modal field patterns, due primarily to the effective CPML.     

低功耗输出脉冲幅度和频谱可调的超宽带发送机设计

A 3-5 GHz low power BPSK modulated impulse radio UWB transmitter is implemented in 0.13μm CMOS technology. In this design the amplitude and spectrum of the output impulse are both tunable to solve the special problem in IR-UWB, where it is difficult to control the spectrum. Measurement results indicate that, by changing the control bits in the gain control circuit and differential circuit, the 3-step peak-to-peak voltage amplitudes are 240, 170 and 115 mV and the center frequency of the impulse can be tuned from 3.2 to 4.1 GHz. A power controlled output buffer is designed to drive the antenna. The total power consumption is only 4.44 mW when transmitting a baseband signal of 100 MHz. The chip area is 1.2 × 1.4 mm^2.     

The Effects Induced by Turbulence and Dust Storms on Millimeter Waves

Dust storms and turbulence consist of a random medium system, its effects on milimeter waves propagation are studied. Attenuation of millimeter waves, its phase shift and cross- polar discrimination are presented. Results show that dust storms mainly effects XPD and phase shift of millimeter waves, turbulence chiefly produces attenuation, in mediocre fluctuation.     

Computation of the Backscattering Power Density for Rainfall in Millimeter Waves Band

The size distribution and canting angle distribution for non-spherical rain drops are taken into account. Utilizing the Muller matrix, the backscattering power densities are computed at different rain rate and different polarization in millimeter waves band, according the rainfall condition in Xi'an, China. Finally the results obtained are discussed.     

移动通信网与因特网的桥梁——WAP

本文首先介绍了无线应用协议(WAP)的基本原理、协议结构和技术实现方式 ,然后介绍了WAP的技术发展和应用前景 ,最后简介了中国移动通信的WAP业务开放情况。     

显微光功率计

报道了由硅光电池组成的适于在显微镜等微焦系统上进行光功率测量的光电型功率计,具有光谱响应范围广、线性好、灵敏度高、稳定性好、速度快、使用方便等特点.其微型光探头适于放置在不同显微载物台的样品玻片及样品池上,包括置于溶液中模拟样品所处的环境与位置,对投射到显微镜玻片样品上的实际光功率进行测定,并具有换档功能,可准确测定不同波长不同水平(0.1～50 mw)的光功率.