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  • Author or Editor: Ming-Yang Wang x
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Abstract

A quantitative method including peak-fitting for determination of the content of short chain branching (SCB) in ethylene/α-olefin copolymers based on differential scanning calorimetry is described. After stepwise isothermal crystallization, the fractions with similar SCB and lamellar thickness are sorted into groups. The content of each group is determined using the peak-fitting area. The statistical terms, the arithmetic mean SCB content , the weighted mean SCB content and the branching broadness index are calculated. Through comparing with the SCB contents measured by 13CNMR analysis, the results show that this method can quantitatively characterize the content of SCB in ethylene/α-olefin copolymers with a high degree of accuracy.

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Abstract  

The concentration of certain toxic and essential elements in various raw materials of Chinese herbs and scientific Chinese medicine were determined by atomic absorption spectrometry (AAS) and instrumental neutron activation analysis (INAA). Correlation of these elements as they exist in the raw materials and in the prescription of medicine were investigated and the approximate intake of elements by patients were estimated. Values of elements determined both by ASS and INAA presented excellent agreement. The ranges of elemental concentrations were found to vary from 104 to 10–1 mg/kg in different kinds of herbs. All herbs exhibit extraordinary enrichment capabilities from the environment for elements such as Mn, Zn, Ca, K, Mg, Cd, Cu, Pb and As. Higher contents of Cd, Pb and As in herbs may be attributed to the uptake of these elements from polluted soil due to industrial and antropogenic activities. It was found that commercial scientific Chinese medicine, SCDBT, contains more elemental concentrations than that of herbs used in the prescription, which may indicate that possible contamination could be caused by unknown ingredients added in the process. A much higher toxic elemental content, such as Pb, Cd and As, has been found in CFH and the daily intake of these elements by the patient will exceed the PTDI values.

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Abstract

The Essential Science Indicators (ESI) database is widely used to evaluate institutions and researchers. The objective of this study was to analyze trends and characteristics of papers in the subject category of water resources in the ESI database of the Institute for Scientific Information (ISI). Distributions of document type, language of publication, scientific output, and publication of journals are reported in this article. Five indicators (the number and ranking of total papers, first-author papers, corresponding-author papers, independent papers, and collaborative papers) were applied to evaluate country, institute, and author performances. In addition, the numbers of authors cited, numbers of institutes cited, numbers of countries cited, and numbers of subject areas cited were also used to evaluate ESI papers. Results showed that 265 papers, all written in English, were listed in 27 journals in the field of water resources. A review paper was more likely to be included in the ESI than a research paper. Journal of Hydrology published the most papers. The USA and UK were the two leading nations. ESI papers published in the US were more likely to involve inter-institutional collaboration than papers published in the UK. The University of Arizona was the most productive institute. Some papers that were almost excluded from the ESI database appear to have consistently received annual high frequencies of citation. Perhaps the 10 year criterion for inclusion in the ESI should be reassessed.

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Abstract  

This study investigates the knowledge diffusion patterns of Nanoscience & Nanotechnology (N&N) by analyzing the overall research interactions between N&N and nano-related subjects through citation analysis. Three perspectives were investigated to achieve this purpose. Firstly, the overall research interactions were analyzed to identify the dominant driving forces in advancing the development of N&N. Secondly, the knowledge diffusion intensity between N&N and nano-related subjects was investigated to determine the areas most closely related to N&N. Thirdly, the diffusion speed was identified to detect the time distance of knowledge diffusion between N&N and nano-related subjects. The analysis reveals that driving forces from the outside environment rather than within N&N itself make the foremost contributions to the development of N&N. From 1998 to 2007, Material Science, Physics, Chemistry, N&N, Electrical & Electronic and Metallurgy & Metallurgical Engineering are the key contributory and reference subjects for N&N. Knowledge transfer within N&N itself is the quickest. And the speed of knowledge diffusion from other subjects to N&N is slower than that from N&N to other subjects, demonstrating asymmetry of knowledge diffusion in the development of N&N. The results indicate that N&N has matured into a relatively open, diffuse and dynamic system of interactive subjects.

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Abstract

To provide an overview of the characteristics of research in China, a bibliometric evaluation of highly cited papers with high-level representation was conducted during the period from 1999 to 2009 based on the Essential Science Indicators (ESI) database. A comprehensive assessment covered overall performance, journals, subject categories, internationally collaborative countries, national inter-institutionally collaborative institutions, and most-cited papers in 22 scientific fields. China saw a strong growth in scientific publications in the last decade, to some extent due to increasing research and development expenditure. China has been more active in ESI fields of chemistry and physics, but more excellent in materials science, engineering and mathematics. Most publications were concerned with the common Science Citation Index subject categories of multidisciplinary chemistry, multidisciplinary materials and science, and physical chemistry. About one half China's ESC papers were internationally collaborative and the eight major industrialized countries (the USA, Germany, the UK, Japan, France, Canada, Russia, and Italy) played a prominent role in scientific collaboration with China, especially the USA. The Chinese Academy of Sciences took the leading position of institutions with many branches. The “985 Project” stimulated the most productive institutions for academic research with a huge funding injection and the universities in Hong Kong showed good scientific performance. The citation impact of internationally collaborative papers differed among fields and international collaborations made positive contributions to academic research in China.

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