中国竹亚科一些属种的整理     

赵奇僧  朱政德  熊文愈 《中国科学院研究生院学报》1980,18(1):20-36

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科研工作的时效性探讨   总被引：2，自引：0，他引：2  

王楚鸿 《研究与发展管理》2001,13(4):62-66

通过对科研工作时效性的理论思考,结合科研工作的实际和案例分析,对科研工作时间投入和科研效益的若干问题进行初步的探讨。  相似文献   

三种数值方法在几种六道木分类中的应用   总被引：1，自引：0，他引：1  

胡嘉琪  朱明远  许自省 《中国科学院研究生院学报》1982,20(4):410-420

   In the last 10—20 years there has bee n increasing awareness of the problem con- cerning the aims and practices of taxonomy.  In particular, there has been growing interest in the development of numerical methods in biological taxonomy as an aid to making systematics a quantitative science, a step which comes in time to almost every scientific discipline.       Numerical taxonomy is the evaluation by numerical methods of the affinity or  similarity between taxonomic units and the employment of these affinities in erecting a hierarchic order of taxa.  The present rapid development of these ideas is presuma- bly a result of the development of computer techniques.       Numerical taxonomic approach has been applied to the studies of entomology and microbiology in China to some extent since 1975. But so far it hasn’t been commonly used in botany.  The present report is a preliminary study on 9 spp. of the genus Abelia.  A set of binary data with 54 characters  is  used  for  computing association coefficient; and a set of quantitative data with 47 characters for distance coefficient and correlation coefficient. For the mathematical models were chosen the non-metric  simple matching association coefficient, the geometrical distance of Riemannian space and correlation coefficient.  Computational procedures are stepwise presented in detail and computer programmes are written in the background of Algol-60 language. Cluster analysis is compared with simple linkage,  average  linkage  and multi-correlation.      The results of DC and CC for 9 spp. of Abelia agree closely with the traditional taxonomy, because the data we collected mainly come from morphological characters. It would seem that the results of quantita tive data are more appropriate for  seed plants.  It is, therefore, postulated that our programes are complementary and very useful to a wide range of classification entities, such as microbes, animals and plants in present situation in China.      In conclusion, a comparison between the  conventional taxonomy  and  numerical taxonomy has been made, and a brief discussion of three problems, i.e. the monothetic versus polythetic, divisive versus agglomerative, weighting versus unweighting.    相似文献   

图书馆自动化系统更新换代时数据转换问题研究     

李月明  丑楚 《情报探索》2006,(9):82-83

文章对基于SQL的图书馆自动化系统向ILASII系统更新换代过程中,数据进行转换时所采取的方法作了较为详细的阐述,研究并提出了数据库间进行数据转换的实施方案。  相似文献   

N,N′-双棕榈酰基乙二胺二乙酸钠的合成和表面活性     

廖文胜  毕只初 《中国科学院研究生院学报》2004,(3)

合成了新型阴离子Gemini表面活性剂N ,N′ 双棕榈酰基乙二胺二乙酸钠 ,并以元素分析、1 HNMR对合成的表面活性剂进行了表征 ;用表面张力法确定了其临界胶束浓度 (cmc) ;对表面活性剂在硅胶上的润湿性进行了实验 ,发现其润湿性远优于十二烷基苯磺酸钠  相似文献   

Climate and litter C/N ratio constrain soil organic carbon accumulation     

Guoyi Zhou  Shan Xu  Philippe Ciais  Stefano Manzoni  Jingyun Fang  Guirui Yu  Xuli Tang  Ping Zhou  Wantong Wang  Junhua Yan  Gengxu Wang  Keping Ma  Shenggong Li  Sheng Du  Shijie Han  Youxin Ma  Deqiang Zhang  Juxiu Liu  Shizhong Liu  Guowei Chu  Qianmei Zhang  Yuelin Li  Wenjuan Huang  Hai Ren  Xiankai Lu  Xiuzhi Chen 《国家科学评论(英文版)》2019,6(4):746

Soil organic carbon (SOC) plays critical roles in stabilizing atmospheric CO₂ concentration, but the mechanistic controls on the amount and distribution of SOC on global scales are not well understood. In turn, this has hampered the ability to model global C budgets and to find measures to mitigate climate change. Here, based on the data from a large field survey campaign with 2600 plots across China''s forest ecosystems and a global collection of published data from forested land, we find that a low litter carbon-to-nitrogen ratio (C/N) and high wetness index (P/PET, precipitation-to-potential-evapotranspiration ratio) are the two factors that promote SOC accumulation, with only minor contributions of litter quantity and soil texture. The field survey data demonstrated that high plant diversity decreased litter C/N and thus indirectly promoted SOC accumulation by increasing the litter quality. We conclude that any changes in plant-community composition, plant-species richness and environmental factors that can reduce the litter C/N ratio, or climatic changes that increase wetness index, may promote SOC accumulation. The study provides a guideline for modeling the carbon cycle of various ecosystem scales and formulates the principle for land-based actions for mitigating the rising atmospheric CO₂ concentration.  相似文献   

档案文化范式变迁机理及其规律解析     

倪丽娟  楚玲菲 《档案学研究》2014,28(4):4-7

近些年,档案文化领域的研究逐渐成为档案学界研究的热点,研究角度十分广泛,研究成果日益丰富。本文站在范式的角度研究档案文化,试图探寻档案文化范式变迁的机理,分析档案文化范式变迁的规律。档案文化范式,是指人们在社会实践活动中,逐渐形成的关于档案、档案工作以及档案事业的思维方式与行为模式所共同构成的模式文化。不同历史时期的档案文化范式呈现不同的特点,由于受到社会背景、社会主体、管理实践、档案学思想和档案学教育的影响,档案文化范式随着时代的发展变化演进变迁,并呈现出一定规律。  相似文献   

图书情报专业创业教育研究   总被引：1，自引：0，他引：1  

储节旺  郭春侠 《图书情报工作》2011,55(13):32-36

认为目前大学生就业形势日益严峻,通过创业实现就业是解决就业问题的一个重要途径。创业教育已经成为高等教育的重要组成部分,在图书情报专业教育中理应占有一席之地。图书情报专业现有的课程体系存在一些与创业教育不相适应的地方。通过调查发现,图书情报专业学生的创业意愿不强烈。因此,需要改革现有课程、培训教师、建设创业文化等措施,推进图书情报专业学生的创业活动。  相似文献   

论《畿辅方言》的"因声求义"     

褚红 《保定学院学报》2010,23(4):69-72

清人王树枏的《畿辅方言》是清末民初一部记载河北古代方言的辞书,在汉语方言学史和词汇史上占有重要地位。王氏以声音通训诂,运用＂因声求义＂训诂原理进行字、词诠解的方法,在传统语言学中占有重要地位。  相似文献   

Robust observer design for multi-motor web-winding system     

Xiaoyan Chu  Xiaohong Nian  Miaoping Sun  Haibo Wang  Hongyun Xiong 《Journal of The Franklin Institute》2018,355(12):5217-5239

This paper develops a novel observer design method for multi-motor web-winding system. Firstly, the multi-motor web-winding system is regarded as a synthetic system with several subsystems, where the dynamic model for each subsystem is given. Then, the nonlinear diffeomorphism transformation is introduced to obtain a transformed system with block triangular structure and the interconnections among the subsystems are allowed. Next, a decentralized high-gain observer with sliding mode is designed for the transformed system, based on which the estimation error dynamics can be got. Sufficient condition of asymptotic stability for estimation error dynamics is derived by the Lyapunov stability theory and the observer gain is obtained. After that, the observer for original multi-motor web-winding system is achieved via inverse transformation. Finally, the simulation and analysis are performed in the three-motor web-winding system to verify the effectiveness of the proposed observer.  相似文献