基于BiCMOS技术的高速数字/模拟转换器

基于BiCMOS技术，进行了高速数字/模拟转换器研究. 以并行输入类型，电流工作模式的16位D/A转换器为载体，进行了电路设计、工艺制作和测试. 在±5.0V工作电压下，测试得到转换速率≥30MSPS，建立时间为50ns，增益误差为±8% FSR，积分非线性误差为1/2 LSB，功耗为500mW.     

Performance characterization of the dynamic programming obstacle detection algorithm.

A computer vision-based system using images from an airborne aircraft can increase flight safety by aiding the pilot to detect obstacles in the flight path so as to avoid mid-air collisions. Such a system fits naturally with the development of an external vision system proposed by NASA for use in high-speed civil transport aircraft with limited cockpit visibility. The detection techniques should provide high detection probability for obstacles that can vary from subpixels to a few pixels in size, while maintaining a low false alarm probability in the presence of noise and severe background clutter. Furthermore, the detection algorithms must be able to report such obstacles in a timely fashion, imposing severe constraints on their execution time. For this purpose, we have implemented a number of algorithms to detect airborne obstacles using image sequences obtained from a camera mounted on an aircraft. This paper describes the methodology used for characterizing the performance of the dynamic programming obstacle detection algorithm and its special cases. The experimental results were obtained using several types of image sequences, with simulated and real backgrounds. The approximate performance of the algorithm is also theoretically derived using principles of statistical analysis in terms of the signal-to-noise ration (SNR) required for the probabilities of false alarms and misdetections to be lower than prespecified values. The theoretical and experimental performance are compared in terms of the required SNR.     

Quality-aware images.

We propose the concept of quality-aware image, in which certain extracted features of the original (high-quality) image are embedded into the image data as invisible hidden messages. When a distorted version of such an image is received, users can decode the hidden messages and use them to provide an objective measure of the quality of the distorted image. To demonstrate the idea, we build a practical quality-aware image encoding, decoding and quality analysis system, which employs: 1) a novel reduced-reference image quality assessment algorithm based on a statistical model of natural images and 2) a previously developed quantization watermarking-based data hiding technique in the wavelet transform domain.     

基于CAN总线的仓库温湿度监控系统的设计

为了提高仓库监控系统的可靠性和传输距离,设计了基于CAN总线的仓库监控系统。系统采用分布式网络结构,主要分为上位机和下位机两部分。上位机主要完成了EPP并口协议的CAN通讯适配器的设计以及仓库人机界面的软件设计;下位机主要完成了CAN节点和温、湿度等参数的传感器选型和对温、湿度等参数控制器的设计。设计的系统满足对大库区的环境参数实时检测的要求。     

基于精简标准单元库的OPC复用技术

提出了一种对标准单元的光学邻近效应校正结果进行复用的方法,并通过将传统标准单元中的所有核心逻辑通过反相器和二选一多路选择器的组合来实现,得到了一套可制造性强的精简标准单元库,从而使OPC复用技术得以有效实施,并将在很大程度上提高芯片生产效率和降低掩模数据存储量.精简标准单元库中单元的电气仿真结果表明其在面积、速度、功耗方面与传统标准单元库相比性能损失很小.     

有源光纤环脉冲复制器工作特性分析

为了研究向全光等效时间采样系统提供被采样一致脉冲序列的技术,讨论了使用有源光纤环脉冲复制器进行脉冲复制的方法。分析了利用环内注入直流光实现对复制器非线性增益与放大自发辐射噪声所导致误差的抑制。通过实验得到了复制器误差随环内注入直流光的变化趋势、复制器复制稳定性和误差分布的测量结果。结果表明,利用有源光纤环脉冲复制器可以有效地产生被采样等效时间周期脉冲序列。     

Nanoporous Copper with Tunable Nanoporosity for SERS Applications

Nanostructured materials with designable microstructure and controllable physical and chemical properties are highly desired for practical applications in nanotechnology. In this article, it is reported that nanoporous copper with a tunable nanopore size can be fabricated by controlling the dealloying process. The influence of acid concentration and etching potential on the formation of nanoprosity is systematically investigated. With optimal etching conditions, the nanopore sizes can be tailored from ～15 to ～120 nm by controlling the dealloying time. It is found that the tunable nanoporosity leads to significant improvements in surface‐enhanced Raman scattering (SERS) of nanoporous copper and peak values of SERS enhancements for both rhodamine 6G and crystal violet 10B molecules are observed at a pore size of ～30–50 nm. This study underscores the effect of complex three‐dimensional nanostructures on physical and chemical properties and is helpful in developing inexpensive SERS substrates for sensitive instrumentations in molecular diagnostics.     

Magnetic Field‐Induced Phase Transformation in NiMnCoIn Magnetic Shape‐Memory Alloys—A New Actuation Mechanism with Large Work Output

Magnetic shape memory alloys (MSMAs) have recently been developed into a new class of functional materials that are capable of magnetic‐field‐induced actuation, mechanical sensing, magnetic refrigeration, and energy harvesting. In the present work, the magnetic &!hyphen;field‐induced martensitic phase transformation (FIPT) in Ni₄₅Mn_36.5Co₅In_13.5 MSMA single crystals is characterized as a new actuation mechanism with potential to result in ultra‐high actuation work outputs. The effects of the applied magnetic field on the transformation temperatures, magnetization, and superelastic response are investigated. The magnetic work output of NiMnCoIn alloys is determined to be more than 1 MJ m^?3 per Tesla, which is one order of magnitude higher than that of the most well‐known MSMAs, i.e., NiMnGa alloys. In addition, the work output of NiMnCoIn alloys is orientation independent, potentially surpassing the need for single crystals, and not limited by a saturation magnetic field, as opposed to NiMnGa MSMAs. Experimental and theoretical transformation strains and magnetostress levels are determined as a function of crystal orientation. It is found that [111]‐oriented crystals can demonstrate a magnetostress level of 140 MPa T^?1 with 1.2% axial strain under compression. These field‐induced stress and strain levels are significantly higher than those from existing piezoelectric and magnetostrictive actuators. A thermodynamical framework is introduced to comprehend the magnetic energy contributions during FIPT. The present work reveals that the magnetic FIPT mechanism is promising for magnetic actuation applications and provides new opportunities for applications requiring high actuation work‐outputs with relatively large actuation frequencies. One potential issue is the requirement for relatively high critical magnetic fields and field intervals (1.5–3 T) for the onset of FIPT and for reversible FIPT, respectively.     

Region-based image retrieval using color-size features of watershed regions

This paper presents a region-based image retrieval system that provides a user interface for helping to specify the watershed regions of interest within a query image. We first propose a new type of visual features, called color-size feature, which includes color-size histogram and moments, to integrate color and region-size information of watershed regions. Next, we design a scheme of region filtering that is based on color-size histogram to fast screen out some of most irrelevant regions and images for the preprocessing of the image retrieval. Our region-based image retrieval system applies the Earth Mover’s Distance in the design of the similarity measure for image ranking and matching. Finally, we present some experiments for the color-size feature, region filtering, and retrieval results that demonstrate the efficiency of our proposed system.     

Enhancement of Spatial Learning-Memory in Developing Rats via Mozart Music

This paper studies the effect of musical stimulations on the capability of the spatial learningmemory in developing rats by behavioral and electrophysiological techniques. Rats, which are exposed to Mozart's Sonata for Two Pianos in D Major, complete learning tasks of the Moriss water maze with significantly shorter latencies, and the power spectrum of alpha band of electrohippocampogram (EHG) significantly increase, compared with the control rats and rats exposed to the horror music. The results indicate that if given the stimulation of Mozart music in the developmental period of the auditory cortex, the capability of the spatial learning-memory can be significantly changed. The enhancement of alpha band of EHG may be related to the change of this function mainly.