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Abstract  

The Web has become an important means of academic information exchange and can be used to give new insights into patterns of informal scholarly communication. This study develops new methods to examine patterns of university Web linking, focusing on Mainland China and Taiwan, and including language considerations. Multiple exploratory investigations into Web links were conducted between universities in these two places. Firstly, inlinks were counted to each university Web site from its national peers using four alternative Web document models. The results were shown to correlate significantly with research productivity in Taiwan but not in the Mainland, although in the latter case less reliable institutional data could have been the cause. For Taiwan, this is the first evidence of a scholarly association with academic linking for a non-English speaking region. It was then ascertained that the same link counts associated more strongly with scientific than social scientific research productivity in Taiwan. This confirms the general assumption of greater Web use by the hard sciences. We then investigated Taiwan-Mainland university cross-links, and found that although English is extensively used on the Web, there was no evidence that it was the language of preference for informal scholarly communication between the two areas.

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Abstract

An investigation of links to 89 US academic departments from three different disciplines gave insights into the kinds of international regions and national domains that linked to them. While significant correlations were found between total counts of international inlinks and total publication impact in Psychology and Chemistry, counts of international inlinks to History departments were too small to give a significant result. The correlations suggest that international links may reflect, to a certain extent, patterns of scholarly communication. Even though History departments attracted a significantly lower percentage of international inlinks than those of Chemistry and Psychology, the main source of links for all three disciplines was from Europe. Analyses of national inlinks, characterized by gTLDs (generic Top Level Domains), showed that the major source of links for all disciplines was.edu sites, followed by.com,.org,.net. As a whole, international regional differences in disciplines were stronger than gTLD differences, although in both cases discrepancies were not of a large scale.

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Abstract  

A survey of linguistic dimensions of Web site hosting and interlinking of the universities of sixteen European countries is described. The results show that English is the dominant language both for linking pages and for all pages. In a typical country approximately half the pages were in English and half in one or more national languages. Normalised interlinking patterns showed three trends: 1) international interlinking throughout Europe in English, and additionally in Swedish in Scandinavia; 2) linking between countries sharing a common language, and 3) countries extensively hosting international links in their own major languages. This provides evidence for the multilingual character of academic use of the Web in Western Europe, at least outside the UK and Eire. Evidence was found that Greece was significantly linguistically isolated from the rest of the EU but that outsiders Norway and Switzerland were not.

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Residues of three pyrethroids in spiked vegetables have been analyzed by HPTLC with two mobile phases in a twin-trough chamber and in horizontal chambers. The spots were detected at λ = 203 nm and the greatest detection sensitivity for the three pyrethroids was 10 ng. Recovery after fortification at 0.5–5.0 mg kg −1 was from 70.20 to 108.5%. The relative standard deviation was 1.59–27.94%.

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A high-performance thin-layer chromatographic method has been developed for determination of four carbamate residues in vegetables. The method uses two mobile phases on silica gel 60 F 254 GLP HPTLC layers, and detection at λ = 243 nm and 207 nm, the average wavelengths of maximum adsorption of pirimicarb and methomyl, and carbaryl and carbofuran, respectively. Recovery of 1.0–5.0 mg kg −1 of the four mixed carbamates from wax gourd and potatoes was 70.05–103.7%. The accuracy and precision of the method were confirmed by means of fortification experiments.

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In this work we have studied the separation of a mixture of the sulfonylurea herbicides (metsulfuron-methyl, chlorsulfuron, bensulfuron-methyl, tribenuron, chlorimuron-ethyl) by HPTLC on silica gel F 254 plates, with two different mobile phases. We also studied the effect of humidity on the separation. Bensulfuron-methyl added to tapwater at levels of 5, 10, and 20 µg kg −1 were determined after extraction by LC 18 SPE. Detection limits of the method are given.

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A simple, rapid, and sensitive high-performance thin-layer chromatographic method has been developed and validated for analysis of residues of imidacloprid, fenitrothion, and parathion in Chinese cabbage. The sample was extracted by sonication in an ultrasonic water bath with acetone-petroleum ether, 5:3 ( v / v ), and the extract was directly applied, as bands, to glass-backed silica gel 60F 254 HPTLC plates. The plates were developed with hexane-acetone, 7 + 3 ( v / v ), in an unsaturated glass twin-trough Camag chamber. Evaluation of the developed HPTLC plates was performed densitometrically with a Camag TLC Scanner 3 controlled by an external PC running Wincats software (Version 1.1.2). The results indicated that the detection limits of imidacloprid ( R F = 0.10), fenitrothion ( R F = 0.59), and parathion ( R F = 0.70) were 5.0 × 10 −9 g, 2.0 × 10 −8 g, 1.0 × 10 −8 g, respectively. Recoveries of the pesticides from Chinese cabbage by use of this analytical method were 80.04–85.22%, and RSD were 4.18–13.15%. The precision and accuracy of the method were generally fit for analysis of pesticide residues in Chinese cabbage.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors: Haiqun Cao, Yongde Yue, Rimao Hua, Feng Tang, Yanhong Shi, Xiangwei Wu, Rong Zhang, and Mengxing Xie

A simple, rapid, and sensitive high-performance thin-layer chromatographic method for analysis of octachlorodipropyl ether (OCDPE) in insecticide formulations has been established and validated. Known amounts of analytical grade OCDPE and its emulsifiable concentrate (EC) or wettable powder (WP) formulations were characterized by HPTLC on silica gel with toluene-acetic acidwater 20:20:1 ( v/v ) as mobile phase; detection was by spraying with silver nitrate-2 m alcoholic potassium hydroxide as chromogenic reagent and exposure to UV light. The plates were evaluated densitometrically at 399 nm. The results indicated that the calibration plot for OCDPE was logarithmic in the range 0.2–5.0 μg per band, and the correlation coefficient for the calibration equation in this range was 0.99. Recoveries from laboratory-prepared test EC and WP formulations using this method were 98.5–103.9% and 95.3–104.3%, respectively, and the respective RSDs were 3.39–4.89% and 2.92–5.33%. The accuracy and precision of the method were suitable for analysis of OCDPE in pesticide formulations.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Ye Yu-xing, Hu Jin-xin, Huang Zi-lin, Shi Wei-qun, Wu Guang-min, Tang Hong-bin, Zhu Wen-bin, Wang Xiao-rong, Zhao Hu-gen, Dong Yu, Sheng Dong, Luo Fang-xiang, and Zhao Yan-ju

Abstract  

The partitioning of actinides from simulated high level liquid waste (HLLW) originated from the Purex process has been studied using a mixture of dihexyl N,N-diethylcarbamoylmethyl-phosphonate (DHDECMP) and tributylphosphonate (TBP) in kerosene (OK). The distribution ratios of actinides were investigated as a function of a number of parameters such as the concentration of nitric acid, salting-out reagent, Gd(III) in the aqueous phase, extractant in the organic phase, and temperature. The extraction complexes, extraction reaction constant k, and thermodynamic parameters H, G and S were determined. The extraction of actinides from simulated HLLW by DHDECMP-TBP/OK has been carried out using a miniature countercurrent centrifugal contactor. The results show that the removal efficiency of actinides is greater than 99.9%. A conceptual flowsheet for the removal of actinides from HLLW is proposed.

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