循环伏安法在润滑油检测中的应用

介绍了循环伏安法的产生背景、原理。应用该技术可以快速、方便地对润滑油中抗氧剂、总酸（碱）值进行测定，并且可以对不同厂家润滑油的抗氧剂包进行区别。该技术还可以有效地评价润滑油的使用寿命和设备工作状况。     

Latchup-free ESD protection design with complementary substrate-triggered SCR devices

The turn-on mechanism of silicon-controlled rectifier (SCR) devices is essentially a current triggering event. While a current is applied to the base or substrate of an SCR device, it can be quickly triggered on into its latching state. In this paper, latchup-free electrostatic discharge (ESD) protection circuits, which are combined with the substrate-triggered technique and an SCR device, are proposed. A complementary circuit style with the substrate-triggered SCR device is designed to discharge both the pad-to-V/sub SS/ and pad-to-V/sub DD/ ESD stresses. The novel complementary substrate-triggered SCR devices have the advantages of controllable switching voltage, adjustable holding voltage, faster turn-on speed, and compatible to general CMOS process without extra process modification such as the silicide-blocking mask and ESD implantation. The total holding voltage of the substrate-triggered SCR device can be linearly increased by adding the stacked diode string to avoid the transient-induced latchup issue in the ESD protection circuits. The on-chip ESD protection circuits designed with the proposed complementary substrate-triggered SCR devices and stacked diode string for the input/output pad and power pad have been successfully verified in a 0.25-/spl mu/m salicided CMOS process with the human body model (machine model) ESD level of /spl sim/7.25 kV (500 V) in a small layout area.     

Influence of quantum capture and tunneling mechanisms on the dark current of bound-to-continuum quantum-well infrared photodetectors

We present a theoretical model for the dark current of bound-to-continuum quantum-well infrared photodetectors (QWIPs), by considering the field-induced mixing effect, tunneling rate and phonon scattering rate between bound and continuum states. Using this model, we can see clearly how these mechanisms significantly influence the Fermi levels of bound and continuum electrons, and thus, the dark current. Nonlinear temperature dependence of the dark current at low temperature is predicted and discussed in detail. The simulated dark currents exhibit good agreement with the experimental results, without use of parameter fitting techniques.     

First break refraction event picking using fuzzy logic systems

First break picking is a pattern recognition problem in seismic signal processing, one that requires much human effort and is difficult to automate. The authors' goal is to reduce the manual effort in the picking process and accurately perform the picking. Feedforward neural network first break pickers have been developed using backpropagation training algorithms applied either to an encoded version of the raw data or to derived seismic attributes which are extracted from the raw data. The authors summarize a study in which they applied a backpropagation fuzzy logic system (BPFLS) to first break picking. The authors use derived seismic attributes as features, and take lateral variations into account by using the distance to a piecewise linear guiding function as a new feature. Experimental results indicate that the BPFLS achieves about the same picking accuracy as a feedforward neural network that is also trained using a backpropagation algorithm; however, the BPFLS is trained in a much shorter time, because there is a systematic way in which the initial parameters of the BPFLS can be chosen, versus the random way in which the weights of the neural network are chosen     

A semantic modeling approach for image retrieval by content

We introduce a semantic data model to capture the hierarchical, spatial, temporal, and evolutionary semantics of images in pictorial databases. This model mimics the user's conceptual view of the image content, providing the framework and guidelines for preprocessing to extract image features. Based on the model constructs, a spatial evolutionary query language (SEQL), which provides direct image object manipulation capabilities, is presented. With semantic information captured in the model, spatial evolutionary queries are answered efficiently. Using an object-oriented platform, a prototype medical-image management system was implemented at UCLA to demonstrate the feasibility of the proposed approach.     

催化裂化汽油选择性加氢脱硫催化剂RSDS-1的开发

介绍了用于催化裂化汽油选择性加氢脱硫催化剂RSDS-1的研究开发，考察了载体、活性组元、金属原子比以及助剂对催化剂选择性的影响。研究结果表明，催化裂化汽油中烯烃的加氢饱和受扩散限制；Co—Mo组合对烯烃饱和的能力相对较弱；较高的Co／Mo原子比有利于提高催化剂选择性；助剂的加入对催化剂选择性有明显的影响；RSDS—1催化剂用于催化裂化汽油选择性脱硫，对不同原料油适应性好，脱硫率可达80％，RON损失小于2个单位，且可长周期稳定运转。     

电镀企业火警和爆鸣事故实例

列举了作者经历的18种火警和爆呜事故，为电镀企业敲响警钟，安全重于泰山。     

Note on ‘Construction of Double Sampling s‐Control Charts for Agile Manufacturing’

He and Grigoryan (Quality and Reliability Engineering International 2002; 18 :343–355) formulated the design of a double‐sampling (DS) s control chart as an optimization problem and solved it with a genetic algorithm. They concluded that the DS s control charts can be a more economically preferable alternative in detecting small shifts than traditional s control charts. We explain that, since they only considered the average sample size when the process is in control, their conclusion is questionable. Copyright © 2006 John Wiley & Sons, Ltd.     

基于DSP+CPLD的高精度信号发生器

介绍了基于直接数字式频率合成(DDS)原理的全数字信号发生器(DSP),利用DSP芯片快速、高精度的运算优势以及CPLD芯片灵活的编程逻辑、大容量存储功能的特点,采用通用可编程芯片以及数字波形合成技术,形成高稳定、高精度、高动态的数字合成信号.该信号发生器可产生0～25 kHz的正弦波、三角波和方波,输出电压峰峰值为0～5 V,频率步进1 Hz,幅度步进0.001 V.