带单相电能显示的三相四线电能表

主要介绍一种新型的三相四线电能表的设计方案,该方案采用了三相电能测量芯片SA9904和Microchip的PIC16F77作为核心器件.本文所设计的电能表不仅可以测量三相有功无功电量,而且可以分别测量三个单相有功电量,并且通过6位LED数码管,实现三相有功无功电量和三个单相电量的循环显示.     

"三个代表"重要思想是党的十六大的灵魂

十六大精神与“三个代表”的重要思想实现了马克思主义同中国实际相结合的第三次历史性飞跃,是当代中国共产党治党治国基本经验的结晶,又是全面建设小康社会宏伟目标的集中体现。     

一种高性价比数字式直流信号源研制

利用8 bit单片机、2片8 bit D/A芯片构成16 bit D/A输出、专用键盘显示器电路8279、两级稳压电源、精密基准电源研制的数字式直流信号源,具有电路简单、操作方便、成本低廉、输出精度高等特点。数字式直流信号源设计包括电源及精密基准源电路、键盘显示电路、直流信号输出即16 bit D/A电路、直流电流输出电路。在实际现场测试结果表明,该信号源性能可靠,相对误差只有0.05%。     

职业高中学生人格状况的量化研究

本文采用美国心理学家卡特尔编制的16种人格因素测验量表(简称16PF),对职中生人格发展状况和心理健康状况进行测试研究.     

关白附内生菌的分离鉴定及其抗菌和细胞毒活性研究

从关白附（Aconitum Coreanum（Levl.）Rapaics）中分离出内生菌共29株,通过TLC检测筛选出2株可能产生生物碱类成分的内生菌.对筛选出的2株内生菌株的发酵培养物分别以纸片法和MTT法进行抑菌和细胞毒活性测定.实验结果显示,2个内生菌株发酵产物对金黄色葡萄球菌、大肠杆菌具有良好的抑菌作用,对肝癌细胞SMMC-7721、胃癌细胞SGC-7901具有良好的细胞毒活性.通过16S rDNA基因序列分析,2株内生菌分别被鉴定为类芽孢杆菌属和芽孢杆菌属细菌.     

高职贫困大学生人格特征分析

使用16PF调查分析高职贫困生的人格特征,发现大多数贫困生有内倾孤独沉默,固执追求完美,谦逊恭顺,审慎内省,进取等特点;贫困文科生有冒险敢为,少有顾忌,不拘小节,敏感多情,很容易激动兴奋,缺乏耐心,心神不定等特点;贫困理科生有被动,畏怯退缩,缺乏自信心,羞怯自卑,保守自制力强,自尊心强等特点;乡村贫困生较内向,谦虚顺从,理智独处,容易抑郁烦恼,易激动兴奋缺少耐心;城镇贫困生较合群,积极主动自信;贫困女生有谦虚温和,善解人意,合群谨慎,直率天真,传统保守,感情丰富等特点;贫困男生独立上进,持之以恒,竞争意识较强,比较现实,情绪较稳,敢于冒险,但容易刚愎固执疑心重。建议教学与管理根据学生的人格特点因材施教。     

泸县沼水蛙16SrRNA基因克隆与系统发育分析

对采于四川省泸县地区的沼水蛙（Hylaranaguentheri）线粒体16SrRNA基因进行扩增测序。经3对扩增引物分别扩增及测序获得长度为550bp、300bp、1000bp核苷酸序列,拼接后序列长度1601bp。核苷酸相似性分析表明,序列与Genbank公布的福建的沼水蛙线粒体16SrRNA基因（KF185060）核苷酸序列相似性最高（99．8％）;与越南地区沼水蛙的16S序列相似性也较高（99％～99．7％）,无明显种间差异,从遗传上证明沼水蛙为广布物种。同时,与亲源关系较近的水蛙类代表物种构建的系统发育树显示。所有沼水蛙聚为一支系,然后与Ranalateralis互为姊妹群。本文同时也对水蛙类的系统发育关系做了初步讨论。     

江西省优秀武警射击手人格特质分析

基于文献资料法、问卷调查法及数理统计法,对江西省135名武警优秀男子射击手进行16PF调查分析,结果表明：1）江西省武警优秀射击手与全国海、路、空三军之间,在16PF人格中有9项特质具有非常显著性差异性（P〈0.01）,反映了江西省优秀射击手的独特性。2）根据军种的不同,江西省武警优秀射击手和全国陆军之间,在16PF人格中还有2种特质具有显著差异性（P〈0.05）,他们更具有恒责任和自律谨慎能力。3）根据军种的不同,江西省武警优秀射击手和全国海军之间,在16PF人格中还有3种特质具有显著差异性（P〈0.05）,他们有恒负责,严肃审慎、沉默寡言,而且自由不保守做事情的性格。4）根据军种的不同,江西省武警优秀射击手和全国空军之间,在16PF人格中还有1项特质具有显著差异性（P〈0.05）,他们比较依赖队友,依赖能力更强,缺少独立的能力。     

Current Issues and Perspectives on Second Language Learning of Science

In this paper we combine the findings from two recent studies relating to participation and attainment in school science – a re‐analysis of existing official data for England and a review of wider international research evidence in the literature relevant to the UK. Although the secondary data are drawn mainly from England, the comprehensiveness of these datasets, together with our inclusion of a review of international studies on maths and science participation provides a useful reference point for an international audience. The research was prompted by concerns over a reduction in the uptake of the physical sciences post‐16 and especially in higher education and interest in ways of encouraging the study of science by students from less prestigious socio‐economic status backgrounds. Such concerns are not unique to the UK. Using large‐scale official datasets we show that participation and attainment in science are stratified by socio‐economic status. Students from poorer families are less likely to take sciences at post‐16 than many other subjects and those who do are then less likely to obtain grades high enough to encourage further study of the subject. No conclusive evidence has been found to explain this satisfactorily. Plausible reasons suggested in the literature include the relative scarcity of local opportunities putting off those who do not wish to study away from home or the perceived time demands of studying science, and so the difficulties of combining part‐time study and part‐time work for those needing to continue earning while studying. Direct support from professional parents may also lead to greater participation in post‐16 science for students from higher SES. Perhaps the simplest explanation is that participation in science at any level is often predicated upon success at the previous educational stage. There are clear differences in science attainment at age 16 between students of differing backgrounds, which could explain the subsequent differential participation. However, these differences are not dissimilar to those for all subjects. The largest gap presented in the paper is between students eligible and not eligible for free school meals. We also show that these patterns appear early in the life of children. At ages 7 and 11, attainment in the three core subjects (English, maths and science) is negatively related to living in an area of deprivation. The paper ends with a discussion of suggestions for research, policy and practice emerging from this review of the evidence.     

Bacterial and archaeal communities in the surface sediment from the northern slope of the South China Sea

Microbial diversity of sediments from the northern slope of the South China Sea was studied by constructing bacterial and archaeal 16S rRNA gene clone libraries. Fourteen bacterial phylogenetic groups were detected, including Gammaproteo-bacteria, Deltaproteobacteria, Planctomycetes, Alphaproteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Chloroflexi, Acidobacteria, Betaproteobacteria, Nitrospirae, candidate divisions OP8 and OP11, and an unknown group. Gammaproteobacteria was the predominant group in bacterial libraries with the percentage ranging from 31.8% to 63.2%. However, archaeal libraries had relatively lower diversity, with most clones belonging to marine archaeal group I uncultured Crenarchaeota. In addition, two novel euryarchaeal clones were detected not to match any culture-dependent or -independent isolates. Compared with other gas hydrate-rich ecosystems and different areas of the South China Sea, a distinct microbial community was revealed in this study.