PLC模糊控制器在煤泥水处理中的应用

根据煤泥水系统的多输入多输出变量特性及其相互之间的动态关系,提出了采用模糊控制技术对其控制的方法以及建立多变量系统的模糊控制规则,并给出了采用PLC处理煤泥水的实现方法。     

Plant DNA Methylation: An Epigenetic Mark in Development,Environmental Interactions,and Evolution

DNA methylation is an epigenetic modification of the genome involved in the regulation of gene expression and modulation of chromatin structure. Plant genomes are widely methylated, and the methylation generally occurs on the cytosine bases through the activity of specific enzymes called DNA methyltransferases. On the other hand, methylated DNA can also undergo demethylation through the action of demethylases. The methylation landscape is finely tuned and assumes a pivotal role in plant development and evolution. This review illustrates different molecular aspects of DNA methylation and some plant physiological processes influenced by this epigenetic modification in model species, crops, and ornamental plants such as orchids. In addition, this review aims to describe the relationship between the changes in plant DNA methylation levels and the response to biotic and abiotic stress. Finally, we discuss the possible evolutionary implications and biotechnological applications of DNA methylation.     

GmIAA27 Encodes an AUX/IAA Protein Involved in Dwarfing and Multi-Branching in Soybean

Soybean plant height and branching affect plant architecture and yield potential in soybean. In this study, the mutant dmbn was obtained by treating the cultivar Zhongpin 661 with ethylmethane sulfonate. The dmbn mutant plants were shorter and more branched than the wild type. The genetic analysis showed that the mutant trait was controlled by a semi-dominant gene. The candidate gene was fine-mapped to a 91 kb interval on Chromosome 9 by combining BSA-seq and linkage analysis. Sequence analysis revealed that Glyma.09g193000 encoding an Aux/IAA protein (GmIAA27) was mutated from C to T in the second exon of the coding region, resulting to amino acid substitution of proline to leucine. Overexpression of the mutant type of this gene in Arabidopsis thaliana inhibited apical dominance and promoted lateral branch development. Expression analysis of GmIAA27 and auxin response genes revealed that some GH3 genes were induced. GmIAA27 relies on auxin to interact with TIR1, whereas Gmiaa27 cannot interact with TIR1 owing to the mutation in the degron motif. Identification of this unique gene that controls soybean plant height and branch development provides a basis for investigating the mechanisms regulating soybean plant architecture development.     

火电厂用中水水质问题及改善措施的分析

针对火电厂用于循环冷却水和锅炉补给水的中水水质不稳定的问题,介绍通过改进污水处理阶段的工艺和深度处理必电厂初级阶段中水以提高中水水质的措施,对节能减排、保护环境吴有重要意义.     

吉林省农业水资源与种植结构关系

本文在大量调研的基础上,就吉林省"十一五"期间实现增加粮食产量的发展目标,根据吉林省水资源现状与支持程度,提出进行农业产业结构的调整与优化思路.     

沙角C电厂一次风机故障分析及处理

风机是火电厂的重要辅机,风机工作点偏离最佳经济工况、运行中出现动叶卡瑟、喘振是风机最常见故障,如果处理不当可能导致火电厂事故停炉。通过对沙角C电厂660MW机组轴流式一次风机在运行时出现动叶卡涩、过力矩、液压油温高等一系列问题的分析,采取相应的措施进行处理,从根本上解决了一次风机的故障,对同类型一次风机的故障处理具有参考作用。     

蛋白质接枝改性腈纶的水解工艺研究

采用NaOH溶液对腈纶进行水解,表面接枝蛋白质制得改性腈纶。讨论了NaOH浓度、水解温度、水解时间对腈纶接枝效果的影响。结果表明:在水解反应温度80~90℃、NaOH溶液质量分数14%、水解时间15 m in时,改性腈纶接枝率较高。力学性能分析和电镜表面观察表明:在腈纶表面接枝大豆蛋白质,不仅可以赋予纤维表面完整的蛋白质覆盖层,而且还可以较好的弥补纤维因水解而产生的表面损伤和力学性能下降等缺陷。     

恰希玛核电工程安全壳筒体钢衬里的埋弧自动焊焊接质量控制

介绍了巴基斯坦恰希玛核电工程(C-2)安全壳钢衬里筒体的基本状况,分析了埋弧自动焊产生终端裂纹的原因.防止埋弧自动焊产生终端裂纹,匹配主要工艺参数是消除焊缝宽度窄而余高大的基本控制方法,正确选择焊剂的颗粒度并合理回收使用焊剂是减小气孔及焊缝表面压气/凹坑缺陷的重要途径,通过二次切割可减小翘曲等波浪变形现象.     

控制系统的脆弱性分析

脆弱性是指一闭环系统的稳定性对参数摄动极端敏感.这类系统的开环频率特性经过距临界点(-1,j0)的近旁,这种与(-1,j0)点之间脆弱的相对关系遇到任何可能的摄动就会遭到破坏.文中分析指出,控制系统的脆弱性可以用Bode积分来进行定量分析.对于一个非最小相位的不稳定对象的控制来说,控制器的不稳定极点与对象的不稳定极点加到一起会大大增加系统灵敏度函数的峰值.故这类系统的设计必然是脆弱的.对于不稳定的多变量对象的控制来说,如果其中一个等价的输出反馈回路中有一个较大的不稳定极点,那么其灵敏度函数也会出现大的峰值,会导致脆弱性,而利用Bode积分则可以避免设计的脆弱性.