高压绝缘子污闪过程特征量的分类和判别

随着电网电压等级的提高和各类污染的加剧,绝缘子污闪事故日益严重,通过有关特征量提取来实现绝缘子表面状态的监测是预防污闪、提高电网可靠性的关键。笔者结合统计学分类和判别的思想,提出了绝缘子特征量的分类方法,并在试验数据抽样训练的基础上,得到了类别的判断方程。交互分析结果表明,Fisher分类法正确性高于Bayes分类法,适合于绝缘子特征量的类别判断。这对绝缘子特征量提取、状态判别及污闪风险预测有重要意义。     

基于CORDIC算法的数字鉴频方法及其在FPGA中的实现

本文给出了一种适合FPGA实现的基于CORDIC(Coordinate Rotation Digital Computer)算法的数字鉴频方法.首先讨论了利用CORDIC算法进行数字鉴相和一阶差分数字鉴频的原理,然后分别给出在FPGA中实现CORDIC算法的流水结构和迭代结构,通过与XILINX自带CORDIC IPCore资源利用情况的比较及FPGA仿真结果表明,基于CORDIC算法的迭代结构和一阶差分实现数字鉴频的方法是高效可行的.     

Viscosity changes of chitosan solution affect physico-functional properties and consumer perception of coated eggs during storage

Effects of storage of chitosan (CH) solution on physico-functional properties and consumer perception of CH-coated eggs were evaluated during 5- and 15-weeks storage at 25 °C and 4 °C, respectively. Seven treatments [CH0 (freshly-prepared), CH1 (stored for 1-week at 25 °C), CH1R (1-week, 4 °C), CH3 (3-weeks, 25 °C), CH3R (3-weeks, 4 °C), CH5 (5-weeks, 25 °C), CH5R (5-weeks, 4 °C)] were applied on eggshell. After 5-weeks storage, CH-solution viscosity decreased by 2.56 and 4.6 times, respectively, at 4 °C and 25 °C while pH slightly increased. CH0 preserved grade-A quality for 4-weeks vs. 1-week for noncoated eggs at 25 °C. After 5-weeks, weight loss (%) of coated eggs at 25 °C (6.04–5.59) was lower than that of noncoated eggs (7.44) but higher than that of all eggs at 4 °C (2.93–2.46). Albumen pH increased while emulsion capacity decreased with increased storage time; however, both were insignificantly affected by CH viscosity. Consumers perceived CH0- and CH1R-eggshell to be glossier than noncoated eggs after 5-weeks. Purchase intent was higher for CH-coated eggs (72–77.3%) than for noncoated eggs (61.3%). Overall, viscosity changes of CH-coating solution had lesser impact on quality of CH-coated eggs than did storage temperature/time of eggs.     

判别分析法在矿井地质构造预测中的应用

叙述了用判别分析方法对矿井地质构造类型进行了预测的原理，方法和步骤，以已采区两个不同构造复杂程度的区域为背景，充分利用钻孔资料提供的信息，以不同抗压强度的岩层厚度，岩性组合等为依据。将主采煤层上下７０ｍ范围的岩层以１０ｍ为间隔划分层段，确定地质变量，建立判别函数，定量地给上断层存在的部位及其可靠程度，并得到了生产实践的合验证。该方法突破了现有的仅用岩层底板标高研究断层的局限性，得出了矿井构造复杂程     

试油层产液性质的多参数综合判别方法研究

准确地判断储层的产液性质,是试油选层和试油方案优化的重要依据,目前常用的判别方法是基于电测解释结论的多因素经验判别,有较大的人为性和随意性,致使正判率和符合率相对较低,一方面增加了无效的试油工作量,另一方面,增加了漏试油气层的风险.为解决这一问题系统收集和统计了塔里木油田碎屑岩地层反映产液性的录井、测井资料和试油成果资料,通过综合分析对比,提出了预测储层产液性质的新方法--综合权值法.该方法通过一定的规则给电测解释结论、岩心含水迹象、滴水试验、含油饱和度、孔隙度、原油粘度等与产液性相关的因素赋以权值,从而求得综合权值,进而对储层产液性质进行综合判别.综合权值法明显优于单纯的电测解释,使油气水层解释的平均符合率和平均正判率都提高了20%.利用该方法判断储层产液性质具有操作简单、判别率高等优点,对于更合理地优选试油层位和优化试油方案具有重要的实际应用价值.     

A real-time neutron-gamma discriminator based on the support vector machine method for the time-of-fiight neutron spectrometer

A new neutron-gamma discriminator based on the support vector machine (SVM) method is proposed to improve the performance of the time-of-fiight neutron spectrometer. The neutron detector is an EJ-299-33 plastic scintillator with pulse-shape discrimination (PSD) property. The SVM algorithm is implemented in field programmable gate array (FPGA) to carry out the real-time sifting of neutrons in neutron-gamma mixed radiation fields. This study compares the ability of the pulse gradient analysis method and the SVM method. The results show that this SVM discriminator can provide a better discrimination accuracy of 99.1%. The accuracy and performance of the SVM discriminator based on FPGA have been evaluated in the experiments. It can get a figure of merit of 1.30.     

Delog资料的最大隶属度岩性判别方法

本以井为中介，用量化的方法建立波阻抗与岩性之间的联系，用概率统计的方法按最大隶属原则判别岩性，实现由波阻抗参数岩性转化。同时采取分层判别的方法，消除非岩性的沉积因素影响，取得较好效果。     

混凝土大坝中差阻式监测仪器的编号识别

根据差阻式电测仪器及其测量系统的原理，并结合其埋设的具体部位、埋设前的率定资料、仪器鉴定资料、电缆电阻、仪器绝缘性能、仪器类型、历史测量数据等指标，提出了辨识仪器编号的方法。在安康水电站部分仪器因电缆盗割后重新恢复观测的应用表明，使用该方法辨识成功率达88％～93％，保证了监测资料的连续性和可靠性。     

水下盾构隧道地震液化数值分析

砂土地震液化会造成地基失效和结构受损,因此场地液化判别至关重要。国内外规范中的液化判别方法简单实用,但均存在局限性。为更准确、全面地进行场地液化判别,利用三维有限差分程序FLAC^3D,结合孟加拉卡纳普里河底盾构隧道项目,对典型钻孔位置土层的抗震液化特性进行数值分析。利用FLAC^3D中的FINN模块建立土层三维模型,在重力平衡和水压力平衡后施加合理的地震波,进行动力计算,计算模型每个单元在计算过程中的最大超孔压比,若最大超孔压比=1,则该位置土体发生液化;若最大超孔压比<1,则该位置土体不会液化。计算后,部分土体的最大超孔压比=1,其他范围土体的最大超孔压比均<1。研究表明该地区土层会发生地震液化,且不同位置处液化深度不同、液化范围也不同,该数值分析液化判别结果与规范法判别结果一致。     

α/β放射性气溶胶的小流量采样快速测量技术研究

针对放射性气溶胶监测仪的便携要求,设计了一套小流量采样快速测量系统和测量方法。采用累积采样累积测量的方式,联合利用能量甄别修正法与α/β比值法去除Rn子体的干扰,实现小流量采样条件下的α/β放射性气溶胶的同时监测。通过对探测下限的分析,表明该方法可满足应急监测的需求,为便携式α/β放射性气溶胶监测仪设计提供了参考。