巨尾桉叶片水提液对小麦幼苗生长的影响   总被引：2，自引：0，他引：2       下载免费PDF全文

廖建良  宋冠华  曾令达 《惠州学院学报》2000,20(4):50-52

巨尾桉是华南地区重要的人工林树种。研究表明,其叶片水抽提物对小麦 生长有显著抑制作用,对种子萌发亦有显著影响．  相似文献   

How Experiments Begin: The Formation of Scientific Collaborations     

Joel Genuth  Ivan Chompalov  Wesley Shrum 《Minerva》2000,38(3):311-348

Multi-organizational collaborations are increasingly important incontemporary science, but their formative processes have beenneglected by scholars in the social studies of science. Based onan examination of 53 collaborations in physics and relateddisciplines, we have found five types of formations.Collaborations that encountered greater difficulties in formingbecame more formal in their organization and management.  相似文献   

THE POLYMERIZATION OF METHYL METHACRYLATE WITH A NEW TIN-BRIDGED YTTROCENE/Al(i-Bu)_3   总被引：1，自引：0，他引：1  

胡蔚秋  孙俊全  潘智达  吴兆立  许育明 《Journal of Zhejiang University. Science. B》2000,(2)

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高中英语语篇阅读教学的构想     

东运达  姚志梅  周曙晶 《衡水学院学报》2000,(2)

语篇阅读教学是一种融预期、多种阅读、语言习得、学法指导及能力培养为一体的综合教学方法,它体现了交际教学和素质教育思想,是培养学生阅读能力的有效方法。因此,在高中英语语篇教学中应注意:1、转变教学思想,确立语篇概念。2、将阅读预期作为语篇阅读的必要准备过程。3、进行快速阅读。4、经心详读,记取细节,深化语篇阅读的效果,最后达到语言习得的目的。  相似文献   

Domestic patents and developing countries: arguments for their study and data from Brazil (1980–1995)     

Eduardo da Motta e Albuquerque 《Research Policy》2000,29(9)

This paper presents data from Brazilian Patent Office (Instituto Nacional de Propriedade Industrial, INPI) and compares them with data from the United States Patent Office (USPTO). Developing countries have technological activities that are important locally but not significant at international level (imitation, local learning, adaptation of foreign innovations). These activities might be patentable only at national level. Therefore, the study of domestic patents of developing countries provides a broader picture than USPTO patents. This paper compares 8309 INPI patents with 475 USPTO patents (between 1980 and 1995). Domestic patent data show peculiarities in the Brazilian case, possibly shared with other countries in similar technological level: (a) high share of individual patents; (b) foreign-owned firms with important activities; (c) low firm involvement in R&D activities. Some characteristics are shared with developed countries: (a) domestic firms as the major patentees; (b) according to firm size, there is a U-shaped distribution of patents; (c) evidences of multi-technology large firms; (d) a relatively small share of firms have more than one patent in the whole period. The contrast between USPTO and national patenting statistics shows different rankings according to ownership structure, leading firms, industrial sectors, and international patent classification. These differences highlight sources of international competitiveness and point to weaknesses in Brazilian innovative activities. This paper concludes evaluating the contributions (and weaknesses) of this database for the evaluation of the Brazilian National System of Innovation.  相似文献   

Paragraph-based representation of texts: A complex networks approach     

Henrique F. de Arruda  Vanessa Q. Marinho  Luciano da F. Costa  Diego R. Amancio 《Information processing & management》2019,56(3):479-494

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PROBLEMS CONCERNING THE LINKAGE BETWEEN GENERAL AND VOCATIONAL EDUCATION AND HIGHER EDUCATION     

Ivan A. Maslarov 《Higher Education in Europe》1988,13(1-2):24-31

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A reply to Rubincam     

Ivan Kalmar 《Interchange》1988,19(2):83-84

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Open-domain conversational search assistants: the Transformer is all you need     

Ferreira  Rafael  Leite  Mariana  Semedo  David  Magalhaes  Joao 《Information Retrieval》2022,25(2):123-148

Information Retrieval Journal - On the quest of providing a more natural interaction between users and search systems, open-domain conversational search assistants have emerged, by assisting users...  相似文献   

Distribution of moisture in reconstructed oil paintings on canvas during absorption and drying: A neutron radiography and NMR study     

Roel Hendrickx  Ester S.B. Ferreira  Jaap J. Boon  Guylaine Desmarais  Dominique Derome  Lora Angelova 《文物保护研究》2017,62(7):393-409

Moisture is a driving factor in the long-term mechanical deterioration of canvas paintings, as well as for a number of physico–chemical degradation processes. Since the 1990s a number of publications have addressed the equilibrium hygroscopic uptake and the hygro-mechanical deformation of linen canvas, oil paint, animal glue, and ground paint. In order to visualise and quantify the dynamic behaviour of these materials combined in a painting mock-up or reconstruction, we have performed custom-designed experiments with neutron radiography and nuclear magnetic resonance (NMR) imaging. This paper reports how both techniques were used to obtain spatially and temporally resolved information on moisture content, during alternate exposure to high and low relative humidity, or in contact with liquids of varying water activities. We observed how the canvas, which is the dominant component in terms of volumetric moisture uptake, absorbs and dries rapidly, and, due to its low vapour resistance, allows for vapour transfer towards the ground layer. Moisture desorption was generally found to be faster than absorption. The presence of sizing glue leads to a local increase of moisture content. It was observed that lining a painting with an extra canvas results in a damping effect: i.e. absorption and drying are significantly slowed down. The results obtained by NMR are complementary to neutron radiography in that they allow accurate monitoring of water ingress in contact with a liquid reservoir. Quantitative results are in good agreement with adsorption isotherms. The findings can be used for risk analysis of paintings exposed to changing micro-climates or subjected to conservation treatments using water. Future studies addressing moisture-driven deformation of paintings can make use of the proposed experimental techniques.  相似文献