Searching high gray scale FPD scanning matrix based on PSO

With the increase of gray scale and flat panel display （FPD） size, subspace bitwise scanning strategy can be replaced traditional scanning method to cut down frame frequency. However, the direct searching strategy （DSS） becomes unfeasible to obtain corresponding high gray scale scanning matrix. Thus, particle swarm optimization （PSO） is introduced to accelerate searching for high gray scale weights scanning matrix （WSM） with its parallelism and global optimization feature. Finally a WSM of 256 gray scales is found out successfully with Matlab, which both gray linearity and scanning efficiency are satisfied.

Optimal strategy of searching FPD weights scanning matrix using GA-PSO

This paper discusses a kind of optimal method used for searching flat panel display （FPD） scanning matrix. The method adopts bionic algorithm： genetic algorithm （GA） and particle swarm optimization （PSO） algorithm. The method using single GA is more time-consuming, and the search efficiency is low in later evolution; the PSO algorithm is easily falling into the local optimal solution and appears the premature convergent phenomenon. Hence, a hybrid approach of GAPSO is found to optimize the search for high grayscale weights scanning matrix. Finally in the acceptable time, it finds a weight scanning matrix （WSM） of 256 gray scales with Matlab, whose scanning efficiency reaches 94.73% and the linearity is very good.

Detecting Impact Damage in Carbon Fabric/epoxy-matrix Composites by Ultrasonic F-scan and Electrical Resistance Measurement

The status and the variation of electrical resistance of impacted carbon fiber/epoxy-matrix composites were studied by ultrasonic F-scan and electrical resistance measurement The experimental results shows that impact damage energy threshold value of carbon fabric/epoxy-matrix composites can determine by using ultrasonic F-scan. When the impact energy exceeds the threshold value, damage is generated in composites. Electrical resistance of impacted composites is changed owing to the contact of each carbon fiber unit in composites, which cause a change of the series-parallel in conductors. The veracity of detecting impact damage in composites can be improved in this case.

隧道三维电阻率E-SCAN超前探测反演与优化方法研究

超前地质预报是隧道施工中必不可少的环节,将地面三维电阻率E-SCAN观测模式引入到隧道超前预报中,其中供电与采集电极都布置在隧道掌子面,可有效降低旁侧干扰因素的影响,提出了基于三维电阻率E-SCAN的隧道超前探测新型观测模式。建立了隧道三维电阻率E-SCAN超前探测地电模型,获得了敏感度矩阵分布特征:矩阵元素数值较小且相差悬殊;元素绝对值随深度衰减迅速;靠近供电与采集电极位置元素绝对值较高。为改善反演的深度定位问题,对敏感度矩阵中元素施加不同大小的增益因子,对原有敏感度矩阵中高值元素进行抑制,对低值元素进行增益,形成了基于敏感度增益因子的隧道三维电阻率E-SCAN超前探测反演优化方法,在理论上可以提高异常体的深度定位精度。开展数值算例与物理模型试验研究,结果表明在隧道三维电阻率E-SCAN超前探测中,相较于常规光滑约束反演,反演优化方法在异常体的深度定位精度方面具有明显优势。

DSC analysis of Al_2O_3-SiO_2 short fiber reinforced Al-Cu-Mg alloy matrix composites

AlO-SiOshort fiber/Al-Cu-Mg matrix composites containing different Mg contents were fabricated using squeeze casting method.Differential scanning calorimeter(DSC) was used to investigate the reaction condition of the composites with different Mg contents.The microstructure of the composites was observed by transmission electron microscopy(TEM).The experimental results show that the Mg content added to the 2024Al matrix significantly affects interfacial condition between Al2O3-SiO2 short fiber and aluminum matrix.At the temperature above 538 ℃,Al2O3-SiO2 short fiber is prone to react with Mg and forms MgAl2O4 reaction product when Mg content added to aluminum matrix is above 1.0wt%.

EFFECT OF REINFORCEMENT VOLUME FRACTION ON PRECIPITATION IN MATRIX OF SiC_p/AI COMPOSITE

The differential scanning calorimetric(DSC) and transmission electron microanalysis (TEM) techniques were used to study the kinetic process of precipitation in matrix of cast SiC_p/2024 composites.The results showed that precipitation reactions of GP zone and intermediate phase S'(Al_2CuMg)in the composites were accelerated compared with SiC-free material,the peak temperatures of both reactions were decreased.The reaction enthalpies of both the GP zone and intermediate phase S' formation in the matrix were substantially decreased after the addition of SiC.TEM analysis found that the alloying element Mg segregated at the SiC/Al interfaces,and was depleted in the matrix near the interface.The precipitation-free zones(PFZ) and precipitation-sparse zones(PSZ) formed near the interfaces,as a results,the volume fraction of precipitates in matrix was reduced.

Identification of Growth Promoter to Fabrication SiCp/Al₂O₃Ceramic Matrix Composites Prepared by Directed Metal Oxidation of An Al Alloy

SiC particulates reinforced alumina matrix composites were fabricated using Directed Metal Oxidation (DIMOX) process. Continuous oxidation of an Al-Si-Mg-Zn alloy with different interlayers (dopents) as growth promoters, will encompasses the early heating of the alloy ingot, melting and continued heating to temperature in the narrow range of 950°C to 980°C in an atmosphere of oxygen. Varying interlayers (dopents) are incorporated to examine the growth conditions of the composite materials and to identification of suitable growth promoter. The process is extremely difficult because molten aluminum does not oxidize after prolonged duration at high temperatures due to the formation of a passivating oxide layer. It is known that the Lanxide Corporation had used a combination of dopents to cause the growth of alumina from molten metal. This growth was directed, i.e. the growth is allowed only in the required direction and restricted in the other directions. The react nature of the dopants was a trade secret. Though it is roughly known that Mg and Si in the Al melt can aid growth, additional dopents used, the temperatures at which the process was carried out, the experimental configurations that aided directed growth were not precisely known. In this paper we have evaluated the conditions in which composites can be grown in large enough sizes for evaluation application and have arrived at a procedure that enables the fabrication of large composite samples by determining the suitable growth promoter (dopant). Scanning electron microscopic, EDS analysis of the composite was found to contain a continuous network of Al2O3, which was predominantly free of grain-boundary phases, a continuous network of Al alloy. Fabrication of large enough samples was done only by the inventor company and the property measurements by the company were confirmed to those needed to enable immediate applications. Since there are a large number of variable affecting robust growth of the composite, fabrication large sized samples for measurements is a difficult task. In the present work, to identify a suitable window of parameters that enables robust growth of the composite has been attempted.

Reaction Processes of the Titanium Matrix Composites Fabricated from Ti-Al-B2O3 System

Titanium matrix composites reinforced with a-Al2O3 and TiB2 particles were fabricated by in situ synthesis from a Ti-Al-B2O3 system. The reaction processes and microstructure were analyzed by using differential scanning calorimetry（DSC）, scanning electron microscopy（SEM） and X-ray diffraction（XRD）. The results showed that the reactions in the Ti-Al-B2O3 system can occur spontaneously and consist of three steps： 1） 15 Al ＋ 7B2O3 → 7α-Al2O3 ＋ AlB12 ＋ 2B; 2） 14 B ＋ 2Al → AlB12 ＋ AlB2 and 3） 7Ti ＋ AlB（12） ＋ AlB2 → 7TiB2 ＋ 2Al. The final reinforcements were composed of α-Al2O3 and TiB2 particles, which were uniformly distributed in the titanium matrix.

Prediction of the Elastic Properties of Short Basalt Fiber Reinforced Al Alloy Metal Matrix Composites

In this paper, a micro-mechanical model is implemented in software for the prediction of local mechanical properties of discontinuous short fiber reinforced composites. The model, based on the Mori and Tanaka method, shear-lag, computational model, Nielsen-Chen model and Miwa’s model is used to predict the elastic behaviour of basalt short fiber reinforced with Al alloy composites. The Al/basalt Metal Matrix Composites (MMCs) contain basalt short fiber from 2.5% to 10% in steps of 2.5 wt.% and are fabricated using squeeze infiltration technique. The effects of fiber length and orientation on elastic properties of Al/basalt MMCs are investigated. A comparison between the experimental data and the theoretical data based on physical models is made, and the significance of the findings is discussed. The results show that as short basalt fiber content was increased from 2.5% to 10% by wt.%, an improvement in Young’s modulus of 13.26% has been observed. Optical microscopy was used to examine the general microstructure and fiber distribution in the composite produced. Scanning Electron Microscopy (SEM) was performed on the fractured surface to understand the failure mechanisms.

玻璃纤维增强不饱和聚酯树脂防火隔板湿热老化特性

为了研究玻璃纤维增强不饱和聚酯树脂防火隔板湿热老化特性,结合电缆隧道内实际温湿环境和加速老化模型对防火隔板进行等效湿热老化处理。通过扫描电镜试验、热重试验、氧指数试验以及冲击强度试验检测了试样的微观形貌、热稳定性、燃烧性能和机械性能。结果表明,老化1周期后试样表面析出白色粉状物、老化3周期后断面出现明显裂痕;微观形貌图显示老化2周期后试样中的树脂从玻璃纤维上脱落,老化5周期后大量玻璃纤维裸露在外。试样质量损失率峰值最终升高45%,冲击强度最终下降41.6%,抗弯强度最终降低47.3%,吸水抗弯强度最终下降42.5%,表明湿热老化后试样热稳定性及机械性能出现明显下降。试样氧指数最终提高28.7%;烟密度等级均满足技术规范标准。上述两项检测无法作为判断湿热老化后防火隔板性能劣化的指标。

数字化辅助一体化纤维桩核及树脂基陶瓷冠修复冠折年轻恒牙1例

桩核修复是临床常见的牙体缺损修复方式,临床常用桩核主要有玻璃纤维预成桩树脂核和个性化一体式桩核。在个性化桩核的材料选择上,由于金属的美观缺陷及氧化锆的弹性模量限制,兼具个性化、机械性能及美学优势的一体化玻璃纤维桩核作为一种新型桩核形式被临床所应用。本文报告1例CAD/CAM一体化纤维树脂桩核及树脂基陶瓷冠修复年轻恒牙冠折的临床病例。

掺黏粒改良粉土的土水特征试验研究

以河南开封金明大道北延道路路基工程低液限粉土为研究对象,通过滤纸法测定不同黏粒含量、压实度的粉土土水特征曲线,研究其基质吸力变化规律;采用扫描电镜试验从微观结构演化角度分析其影响机制。结果表明:加州承载比CBR值随黏粒含量与压实度的增加均单调增大;不同压实度下掺黏粒改良粉土的饱和含水率均随黏粒含量的增加呈先增大后减小趋势;任一黏粒含量下,土水特征曲线具有明显的阶段性特征,黏粒含量为15.5%、20.5%、26.5%的土水特征曲线存在基质吸力保持相对恒定的平台期;黏粒含量的增加使得重塑土样的微观结构逐渐紧密,粉黏粒间的接触方式由线或面的接触逐渐转变为胶结及包裹镶嵌作用。根据规范要求,掺黏粒改良粉土可应用于公路路基填筑。

生理通气辅助超高分辨率CT扫描技术探讨

目的：探讨生理通气辅助超高分辨率CT扫描技术（简称G-方案）,提高对肺部局灶性磨玻璃密度灶（f GGO）的细节显示。方法：临床低剂量肺癌筛查中检出的连续20例f GGO患者（男9例,女11例,35~74岁,平均53±11岁）纳入研究,前10例对病灶范围进行常规超高分辨率靶扫描和G-方案扫描,后10例利用筛查原始数据对病灶范围进行回顾性1024矩阵靶重建和G-方案扫描。2位高年资医生共同评价所得图像,评价指标包括：图像细节显示清晰度主观评价、病灶和周围肺野CT值,并进行统计学分析。结果：G-方案扫描图像上磨玻璃灶细节显示清晰度明显优于常规超高分辨率扫描和回顾性重建,病灶所在区域背景肺野CT值明显低于常规超高分辨率扫描（P〈0.05）。病灶与背景之间的密度差（即相对密度值）在各组间没有显著性差异。结论：生理通气辅助帮助背景肺过度充气,结合超高分辨率CT扫描可以增加磨玻璃灶的细节显示能力,进而提高f GGO的诊断准确率。相对密度值可能更适合磨玻璃结节的密度评价。

方阵扫描式自动清洗系统

介绍了方阵扫描式清洗系统。该系统可做成自动式或半自动式。垂直驱动机构、清洗架、垂直行走机构等部件具有互换性。

导电聚苯胺/二氧化锰复合材料原位化学合成制备及表征

通过合理选择二氧化锰加入苯胺/过硫酸铵/酸水反应体系的时间,制备了各种含量的聚苯胺/二氧化锰复合材料(PANI/MnO2)。用FTIR、UV-VIS、XRD和SEM对原位制备的PANI/MnO2进行了表征。XRD证明了原位合成的复合材料中聚苯胺组分为无定型,MnO2的晶型在反应前后未发生变化。SEM证明了反应中形成的聚苯胺倾向于在MnO2颗粒表面沉积,得到一种包裹型的PANI/MnO2复合材料。用苯胺的盐酸溶液在静止状态下处理复合材料,可得到一种树状珊瑚形貌的聚苯胺,这种形貌的聚苯胺不同于酸水体系中常见的颗粒状聚苯胺。

电阻率三维反演中偏导数矩阵的求取与分析

利用共轭梯度选代技术的电阻车三维反演法是近年来发展的快造、有效的方法，它只需求取Jacobian矩阵G与任一向量x的乘积Gx及GT与任一向量y的乘积结果GTy，避免直接求取G和GTG，从而大大地减少了工作量。在此基础上，本文引入求取G的Rodi算法，导出了E-SCAN三维数据反演中Gx及GTy的拓展形式，只需作一次正演便可同时求得Gx及GTy，实现了每次反演迭代仅需作一次正演计算，从而大大地提高了运算速度。此外，本文还对灵敏度矩阵进行了分析，讨论了E-SCAN测量区域以外的分群情况，这对实际数据的反演解释有重要的意义。

陆地棉体细胞胚胎发生过程中的细胞外基质研究(英文)

研究棉花体细胞胚胎发生对于促进棉花基因工程育种具有重要意义。利用扫描电镜和透射电镜对陆地棉体细胞胚胎发生过程的研究发现,细胞外基质在棉花体细胞胚胎发生的不同阶段呈现出有规律的动态变化。当普通愈伤组织细胞发育成胚性愈伤组织时,细胞外基质就会出现;随着原胚的形成,细胞外基质就会形成发达的网络状结构;随着胚状体的进一步形成和发育,细胞外基质则逐渐降解。在愈伤组织和非胚性愈伤组织中,始终未发现细胞外基质。结果表明,细胞外基质与体细胞胚胎发生能力关系密切,是原胚形成的重要标记。

钛基纳米金刚石FED驱动电路设计

简要介绍了钛基纳米金刚石涂层的场发射阴极的工艺。设计了AT89S51单片机为控制核心的逻辑电路和以高压驱动芯片IR2113与高压MOS管为主的高压驱动电路,采用51汇编语言编写了控制驱动程序,在16×16矩阵选址的钛基纳米金刚石涂层的FED器件上实现了简单图形和字符的动态显示。给出了实现大屏幕矩阵显示的驱动电路的单片机与后级逻辑控制电路的连接方法。

基于空间自相关和时空扫描统计量的聚集比较分析

聚集是区域经济研究中的重点问题之一,而聚集定位问题又是深入分析聚集需要解决的首要问题。由于聚集具有高度的尺度敏感性,采用空间自相关方法分析时,尺度选择容易受研究者主观判断的影响,而且空间自相关方法也未考虑聚集的时间特征。与之相比,Kulldorff等学者提出的扫描统计量方法表现出了明显的优势。研究探索性地选用浙江省各市、县工业从业人口的聚集问题,从尺度选择、尺度转换和时空融合三个方面,比较了空间自相关和时空扫描统计量方法在探测聚集问题上的差异性,进而证实了时空扫描统计量方法不仅有效解决了人为选择尺度的偏倚问题,实现了尺度推绎、转换的自动化,而且更加有利地融合了立体、动态、多尺度的时空分析优势。

利用薄层CT技术和Matlab软件辅助建立下颌骨三维有限元模型

目的 :寻求一种更为快捷、精确的全牙列下颌骨三维有限元模型建立方法。方法 :应用薄层CT技术和Matlab软件 ,结合Ansys三维有限元专用软件对 10 6层层厚为 1mm的CT断层影像进行分析处理。结果 :建立了更为精确、应用更为广泛的包含全牙列的下颌骨三维有限元模型。使用Matlab开发一种专门用于BMP图片识别的软件 ,并将所获取数据直接写入Ansys三维有限元软件 ,大大提高了建模效率。结论 :薄层CT技术的应用使得有限元模型的建立更为精确 ,同时Matlab软件的高效识别 ,极大程度提高了建模效率 ,适用于口腔医师对有限元模型的前期处理。