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  • Author or Editor: Hui Wang x
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Abstract  

According to the definition of reliability-based citation impact factor (R-impact factor) proposed by KUO & RUPE and the cumulative citation age distribution model, a mathematical expression of the relationship between R-impact factor and impact factor is established in this paper. By simulation of the change processes of the R-impact factor and impact factor in the manipulation process of the impact factor, it is found that the effect of manipulation can be partly corrected by the R-impact factor in some cases. Based on the Journal Citation Report database, impact factors of 4 normal journals and 4 manipulated journals were collected. The journals’ R-impact factors and self-cited rates in the previous two years were calculated for each year during the period 2000 to 2007, and various characteristics influenced by the manipulation were analyzed. We find that the R-impact factor has greater fairness than the impact factor for journals with relatively short cited half-lives. Finally, some issues about using the R-impact factor as a measure for evaluating scientific journals are discussed.

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Abstract

The desorption characteristics of methane from a Maxsorb II specimen of activated carbon were measured over the temperature range of 281–343 K and at pressures up to 1.2 MPa. The technique of measuring the dead volume in the measurement system using helium calibration has also been perfected. The desorption data were fitted to two isotherm models proposed by Tóth and Dubinin–Astakhov with an accuracy better than 0.004 g g−1. The data are compared with those from adsorption and correlations are developed by combining the adsorption and desorption data. The Henry's law coefficients and their relations with extrapolated isosteric heat of adsorption at saturation are analyzed.

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This is a study for criteria to judge the melting point of semi-crystalline polymers from the DSC endotherm for polymer melting. Beyond standard indium DSC melting results an evaluation has been made on a series of polyethylenes for which crystal sizes were measured and predicted from Raman LAM analysis. The results confirm the conclusion of Prof. Wunderlich that the DSC content of melting is the proper basis of reporting melting points.

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Abstract  

The reaction of urea with ZnO was investigated by FTIR and TPD. It was found that urea was thermally decomposed into isocyanic acid on ZnO, and the adsorbed isocyanic acid reacted with ZnO to form zinc isocyanate. Catalytic evaluation showed that ZnO had high activity towards urea methanolysis in a batch reactor, and zinc element and isocyanate were all detected in the product solution. Furthermore, the soluble zinc content was proportional to the DMC yield. Sample analyses suggested that the soluble zinc existed in the form of Zn(NCO)2(NH3)2, which originated from the reaction of ZnO with urea. It was the complex (not ZnO) that catalyzed the urea methanolysis. Based on these observations, a possible mechanism was suggested.

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Abstract  

The thermal stability of sheepskin collagen cross-linked with chrome sulfate and mimosa (MI)–oxazolidine (OZ), respectively, had been researched in this experiment. All samples’ shrinkage temperatures (T s) are determined by a special T s-testing-apparatus and denaturation temperatures (T d) are determined by the differential scanning calorimetry. The relations between the modified collagens containing moisture and their hydrothermal stability, T s or T d, were studied. The results show that the cross linking agents can enhance the thermal stability of modified collagen whose T s are 109.8 and 110.6 °C for collagen treated with chrome and MI–OZ, respectively. When the samples contain 25–71.9% moisture for chrome leather and 20–71.1% for leather treated with MI–OZ, the hydrothermal stability will decrease with the increase of moisture. It was found that the difference between T s and T d of collagen modified by chrome is more obvious than that of collagen modified with MI–OZ. And when the moisture of chrome leather exceeds 55%, T d cannot express thermal stability of modified collagen as a substitute for T s, and the moisture is 40% for leather tanned with MI–OZ.

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Abstract

The aim of this study is to map the intellectual structure of digital library (DL) field in China during the period of 2002–2011. Co-word analysis was employed to reveal the patterns of DL field in China through measuring the association strength of keywords in relevant journals. Data was collected from Chinese Journal Full-Text Database during the period of 2002–2011. And then, the co-occurrence matrix of keywords was analyzed by the methods of multivariate statistical analysis and social network analysis. The results mainly include five parts: seven clusters of keywords, a two-dimensional map, the density and centrality of clusters, a strategic diagram, and a relation network. The results show that there are some hot research topics and marginal topics in DL field in China, but the research topics are relatively decentralized compared with the international studies.

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Abstract

New types of S2O8 2−/Al-x wt%Ce–Zn–O solid acid catalysts were prepared by the sol–gel method. Their catalytic performances for the synthesis of n-butyl acetate from acetic acid and n-butanol were investigated. The characterization of prepared catalysts was performed using XRD, IR, TG-DSC and SEM. The experimental results showed that the S2O8 2−/Al-2.5 wt%Ce–Zn–O solid acid catalyst exhibited an optimal esterification performance with 98.71% esterification efficiency under the optimum synthesis conditions. Moreover, the S2O8 2−/Al-2.5 wt%Ce–Zn–O solid acid catalyst retained its high activity with above 95% esterification efficiency after being used repeatedly for seven times, which indicated that the S2O8 2−/Al-2.5 wt%Ce–Zn–O solid acid catalyst had excellent stability.

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Abstract  

The kinetics of stripping of thorium(IV) and uranium(IV) from tributylphosphate (TBP)-kerosene with dilute nitic acid solution has been studied using the Lewis cell technique. The effects of concentrations of Th(IV), U(IV), nitric acid, TBP, temperature and stirring speed on the stripping rate have been examined. The result show that the stripping rates of Th(IV) and U(IV) are all controlled by diffusion process.

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Abstract  

23-Hydroxybetulinic acid (23-HBA) is the efficient antitumor compound extracted from the roots of a Chinese Medicinal Herb, Pulsatilla chinensis (Bge) Regel. To evaluate the effect of radioiodination on cytotoxicity, 23-HBA was radioiodinated with 125I. 125I-23-HBA could be prepared in high yields and good radiochemical purity and was characterized using reverse phase HPLC. In ICR mice bearing Liver Cancer HepA tumor, 125I-23-HBA showed a tumor uptake of 2.1% ID/g at 2 h p.i. and 0.15% ID/g at 48 h p.i on i.v. injection. When injected intratumorally, greater tumor uptake and retention was observed (20% ID/g at 2 h p.i. and 4.6% ID/g at 48 h p.i. respectively).

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Abstract  

In boron neutron capture therapy (BNCT), the proportion of the fast neutron in the tumor (PFN) must be no more than 3%. If a D–T neutron generator is used as a thermal neutron source in BNCT, the moderator must be optimized to decrease the PFN. Based on the analysis of the theory, water, heavy water, polythene, graphite, lead, and tungsten were used to moderate the fast neutrons. If the three-layer material is composed of a 4 cm thickness layer of tungsten, a 13 cm thickness layer of lead, and a 23 cm thickness layer of heavy water, its thermalization efficiency (TE) is highest, which is increased by 191.5% than the maximum TE moderated by single-layer materials and by 19.3% than the maximum TE moderated by double-layer materials.

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