上海光源同步光监测系统第一面萃取镜设计

本文介绍了上海光源(SSRF)同步光监测系统第一面萃取镜的设计.设计要求从同步光中尽可能不失真地分离出可见光.设计难点在于同步光中的高能X射线会致使萃取器件发热灼损,产生形变,影响可见光成分的波前和幅度.我们通过对同步光的功率谱分析和基于ANSYS程序的受热形变分析,设计出一面带水冷系统的铍镜用以反射可见光和透射X射线,以满足设计要求.     

计算机高速数字电路设计技术

介绍了电源分布系统和传输线阻抗对高速电路设计的影响,并根据实践经验对如何处理高速电路电源系统的问题和注意事项提出一些指导意见,该文将对越来越多的设计者涉足高速电路的设计提供很好的帮助。     

基于局部回归模型的图像超分辨率重建

针对基于稀疏重建的图像超分辨率(SR)算法一般需要外部训练样本,重建质量取决于待重建图像与训练样本的相似度的问题,提出一种基于局部回归模型的图像超分辨率重建算法。利用局部图像结构会在不同的图像尺度对应位置重复出现的事实,建立从低到高分辨率图像块的非线性映射函数一阶近似模型用于超分辨率重建。其中,非线性映射函数的先验模型是直接对输入图像及其低频带图像的对应位样本块对通过字典学习的方法得到。重建图像块时利用图像中的非局部自相似性,对多个非局部自相似块分别应用一阶回归模型,加权综合得到高分辨率图像块。实验结果表明,该算法重建的图像与同样利用图像具有自相似性的相关超分辨率算法相比,峰值信噪比(PSNR)平均提高0.3~1.1 dB,主观重建效果亦有明显提高。     

大功率开关磁阻电动机微机控制系统研究

用机电能量转换的原理分析了开关磁阻电动机的运行及其机械特性.设计研究了以定子带极靴的三相开关磁阻电动机为控制对象,以变参数比例算法为手段,配以80C196单片机为核心的完整的大功率开关磁阻电动机微机控制系统.该控制系统采用硬软件结合的控制方式,提高了系统的可靠性和抗干扰性,解决了系统的稳定性和快速性.     

A proteomic analysis of green and white sturgeon larvae exposed to heat stress and selenium

Temperature and selenium are two environmental parameters that potentially affect reproduction and stock recruitment of sturgeon in the San Francisco Bay/Delta Estuary. To identify proteins whose expression is modified by these environmental stressors, we performed a proteomic analysis on larval green and white sturgeons exposed to 18 or 26 °C and micro-injected with Seleno-L-Methionine to reach 8 µg g⁻¹ selenium body burden, with L-Methionine as a control. Selenium and high temperature induced mortalities and abnormal morphologies in both species, with a higher mortality in green sturgeon. Larval proteins were separated by two-dimensional gel electrophoresis and differential abundances were detected following spot quantitation and hierarchical cluster analysis. In green sturgeon, 34 of 551 protein spots detected on gels showed a variation in abundance whereas in white sturgeon only 9 of 580 protein spots were differentially expressed (P < 0.01). Gel replicates were first grouped according to heat treatment. Fifteen of these spots were identified using MALDI TOF/TOF mass spectrometry. Proteins involved in protein folding, protein synthesis, protein degradation, ATP supply and structural proteins changed in abundance in response to heat and/or selenium. 40S ribosomal protein SA, FK506-binding protein 10, 65 kDa regulatory subunit A of protein phosphatase 2, protein disulfide isomerase, stress-induced-phosphoprotein 1, suppression of tumorigenicity 13 and collagen type II alpha 1, were differentially expressed in high temperature treatment only. Serine/arginine repetitive matrix protein 1, creatine kinase, serine peptidase inhibitor Kazal type 5 and HSP90 were sensitive to combined temperature and selenium exposure. Valosin-containing protein, a protein involved in aggresome formation and in protein quality control decreased more than 50% in response to selenium treatment. Potential use of such proteins as biomarkers of environmental stressors in larval sturgeons could indicate early warning signals preceding population decline.     

Microfabrication of polytetrafluoroethylene using SR direct etching

Polytetrafluoroethylene (PTFE) is a very attractive material for various fields because of its chemical resistance, insulation properties, and hydrophobic properties. However, it is difficult to fabricate PTFE microstructures with conventional techniques such as semiconductor processes or micromachining. We have succeeded in the fabrication of high‐aspect‐ratio microfluidics parts from PTFE by direct in‐vacuum photo‐etching utilizing synchrotron radiation (SR) at energy levels from 2 to 12 keV. This paper presents an analysis of the mechanisms of the PTFE microfabrication process and describes newly discovered processing characteristics of PTFE. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(4): 49–54, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21152     

Experimental Evaluation of Characteristics of SR Motor Made of Permendur

A switched reluctance (SR) motor has a doubly salient pole structure. The performance of the SR motor strongly depends on the magnetic properties of the core material, since it consists only of an iron core and copper windings. This study experimentally evaluates the performance of an SR motor made of permendur (Fe–49% Co alloy), which has very high saturation flux density and low core loss. Two types of SR motors that have the same dimensions but different core materials are used: one motor is made of the conventional nonoriented Si steel, and the other is made of permendur. Comparison of the characteristics of the two motors shows that the performance of the permendur SR motor surpasses that of the conventional one in terms of output power and efficiency. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(1): 51–57, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22431     

Effect on crystalline structure of AISI M2 steel using tungsten–thorium electrode through MRR,EWR, and surface finish

To investigate on the crystalline structure of AISI M2 steel by using tungsten–thorium electrode in electrical discharge machining (EDM) process was studied. Furthermore, the investigation were carried out for finding the value of material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) of tool steel material depending upon three variable input process parameters. On the basis of weight loss, the value of MRR and EWR were calculated at optimized process parameter. Subsequently, surface topography of the processed material were examined through different characterization techniques like scanning electron microscopy (SEM), Optical surface profiler (OSP) and Atomic force microscopy (AFM), respectively. In XRD study, broadening of the peak was observed which confirmed the change in material properties due to the homogeneous dispersion of the particles inside the matrix. Lowest surface roughness and MRR of 0.001208 mg/min was obtained. Minimum surface roughness was obtained 1.12 μm and 2.18427 nm by OSP and AFM study, respectively. Also, minimum EWR was found as 0.013986 mg/min.     

A wavelet transform based POCS Superresolution algorithm

Research interest in multi-frame Superresolution has risen substantially in recent years.This paper presents a modified Projection Onto Convex Set (POCS) superresolution method based on wavelet transform.The method analyzes the image formation model from wavelet multiresolution analysis point of view and defines an closed convex set and its corresponding projection based on wavelet transform.An iterative procedure is utilized to reduce the estimated errors of the result image,and this guarantees the estimated image to lay in the intersection of different convex sets,thus produces a high resolution image with a reduced error.The effectiveness of the algorithm is demonstrated by experimental results.     

Effect of Kollidon VA®64 particle size and morphology as directly compressible excipient on tablet compression properties

The study evaluates use of Kollidon VA^®64 and a combination of Kollidon VA^®64 with Kollidon VA^®64 Fine as excipient in direct compression process of tablets. The combination of the two grades of material is evaluated for capping, lamination and excessive friability. Inter particulate void space is higher for such excipient due to the hollow structure of the Kollidon VA^®64 particles. During tablet compression air remains trapped in the blend exhibiting poor compression with compromised physical properties of the tablets. Composition of Kollidon VA^®64 and Kollidon VA^®64 Fine is evaluated by design of experiment (DoE). A scanning electron microscopy (SEM) of two grades of Kollidon VA^®64 exhibits morphological differences between coarse and fine grade. The tablet compression process is evaluated with a mix consisting of entirely Kollidon VA^®64 and two mixes containing Kollidon VA^®64 and Kollidon VA^®64 Fine in ratio of 77:23 and 65:35. A statistical modeling on the results from the DoE trials resulted in the optimum composition for direct tablet compression as combination of Kollidon VA^®64 and Kollidon VA^®64 Fine in ratio of 77:23. This combination compressed with the predicted parameters based on the statistical modeling and applying main compression force between 5 and 15?kN, pre-compression force between 2 and 3?kN, feeder speed fixed at 25?rpm and compression range of 45–49?rpm produced tablets with hardness ranging between 19 and 21?kp, with no friability, capping, or lamination issue.