高阶数字控制系统的直接数字设计方法

该设计是利用解析方法直接将高阶闭环离散系统的极点配置成为典型二阶离散系统的极点，从而使高阶系统达到或接近典型二阶系统的性能指标，为此所确定的数字控制器的结构和参数与被控对象的阶次和滞后时间有关，计算机仿真结果有效地证明了本文设计思想的可行性。     

百花水库水质模拟及季节性水质恶化控制对策

猫跳河梯级水库自20 世纪90 年代起频繁出现季节性突发污染事件. 选择位于猫跳河干流的百花水库作为研究对象, 对其水温、溶解氧(dissolved oxygen, DO)浓度、营养盐浓度进行了为期12 个月的连续监测. 通过分析水库垂直剖面方向上水温及DO 浓度的季节变化趋势, 验证了水体季节性分层现象是导致突发水质恶化的主要原因. 引入水质分析模拟程序(water quality analysis simulation program, WASP) 对水温、DO 浓度、NH⁺ ₄ 浓度进行模拟, 模拟结果与监测值季节变化趋势吻合, 证明该模型可以应用于百花水库的水质模拟. 利用WASP 对水库进行了流量调度模拟. 结果表明, 进行有效的季节性水量调控可以达到改善该水库季节性缺氧状况的目的.     

Recent advances in brown adipose tissue biology

In mammals, white adipose tissue （WAT） store energy, whereas brown adipose tissue （BAT） burns energy. As a thermogenic organ, BAT can help maintain body temperature during cold exposure. Owing to its important roles in energy metabolism and regulating triacylglycerol levels, BAT has received great attention in treating obesity and its related diseases. Recent studies have suggested that BAT may secrete factor（s）—batokines—to regulate whole- body energy metabolism. In this review, we summarize the recent advances in the formation and function of BAT, as well as molecules that regulate the activity of BAT and beige fat.     

离心泵运转工况的调节

文章通过对泵工况调节的几种方法对比 ,指出了各种方法的优缺点 ,并简要介绍了在实际工作中的应用     

浅谈高校图书馆员的不良心理与调控

列举了当前高校图书馆员中存在的几种不良心理,分析了由不良心理引发的后果,并从提高馆员的社会地位、构建图书馆良性运行机制、加强图书馆员的自我调适等方面提出了相应的调控措施。     

二次调节伺服加载系统的耦合影响

针对二次调节伺服加载系统,建立了数学模型,利用MATLAB仿真软件,对液压和机械耦合干扰下的系统控制性能进行了仿真研究。仿真结果表明,随着负载压力、输出转矩和输出转速的波动幅度的增大,系统的控制精度明显变差,转矩控制系统受负载压力波动的影响大于转速控制系统,转矩波动对转速控制系统的影响大于转速波动对转矩控制系统的影响。     

电力市场环境下古诺模型与经济调度模型的比较

为了解决电力市场运营环境下的个体利益与整体利益冲突问题,将古诺模型与经济调度模型进行比较,分析了基于古诺模型的经济调度,给出了简捷的古诺均衡方法.比较结果表明:古诺模型既可以充分满足电力市场竞争环境下的电厂追求利润最大化的要求,又可以协调各电厂间的利益分配关系,是一种可以用于多种市场条件下的均衡模型.     

基于分层八邻域方向预测算子的IC芯片图像拼接技术

为了对IC芯片进行精密光学检测,需要完整而准确地获取芯片形貌的图像.文中针对IC芯片表面形貌图像的获取要求,提出了一种基于分层八邻域方向预测算子的模板匹配方法,并运用于高精度要求的IC芯片图像处理工作中.通过对获得的芯片显微图像的重叠部分进行匹配点的快速准确搜索,进而实现了芯片精密显微图像的高速拼接处理.编程实验证明,采用该方法可获得IC芯片表面的清晰图像,使芯片的形貌和缺陷等细节能够得到很好的展现.     

五鹿山国家级自然保护区白皮松生长规律研究

根据白皮松自然生长林标准样地调查资料,选择优势木进行树干解析,对白皮松的胸径、树高、材积生长规律进行最优模型模拟,绘制其生长曲线,并探讨白皮松的胸径、树高、材积的生长规律.结果表明,白皮松胸径、树高、材积生长过程的最优模型依次为:d=-0.027 7x2 1.126 3x 0.402 1(R=0.999 34);h=-0.032 4x2 1.006 3x-0.674 3(R=0.996 34);v=0.000 2x2 0.000 5x 0.000 4(R=0.999 55).白皮松林生长过程中,应该在20~25 a左右首次间伐,为生长提供足够的生长空间;在60 a左右进行第2次间伐,以缓解生长压力;直到175 a左右,林分成熟,此时才可进行采伐.     

Genetic background of phenotypic variation

A noteworthy feature of the living world is its bewildering variability. A key issue in several biological disciplines is the achievement of an understanding of the hereditary basis of this variability. Two opposing, but not necessarily irreconcilable conceptions attempt to explain the underlying mechanism. The gene function paradigm postulates that phenotypic variance is generated by the polymorphism in the coding sequences of genes. However, comparisons of a great number of homologous gene and protein sequences have revealed that they predominantly remained functionally conserved even across distantly related phylogenic taxa. Alternatively, the gene regulation paradigm assumes that differences in the cis-regulatory region of genes do account for phenotype variation within species. An extension of this latter concept is that phenotypic variability is generated by the polymorphism in the overall gene expression profiles of gene networks. In other words, the activity of a particular gene is a system property determined both by the cis-regulatory sequences of the given genes and by the other genes of a gene network, whose expressions vary among individuals, too. Novel proponents of gene function paradigm claim that functional genetic variance within the coding sequences of regulatory genes is critical for the generation of morphological polymorphism. Note, however, that these developmental genes play direct regulatory roles in the control of gene expression.