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961.
962.
In enhanced glow discharge plasma immersion ion implantation (EGD-PIII) that involves a small pointed anode and large area tabular cathode, the high negative substrate bias not only acts as the plasma producer but also supplies the implantation voltage. Consequently, an electric field is created to focus the electrons and the electron focusing field in turn enhances the glow discharge process. In this work, the discharge characteristics of EGD-PIII are investigated experimentally. The discharge initiation and extinction characteristics during pulsed biasing are discussed. The duration of the post pulse-off plasma is explained from the viewpoint of particle motion and experimentally verified by employing an auxiliary disk. Our experiments show that a dual-pulse method may be utilized to determine the remnant plasma. 相似文献
963.
Zhi-Yong Jiao Jun-Mao Ma Ning Li Xia Fu 《International Journal of Theoretical Physics》2008,47(11):2841-2849
In this paper, we investigate entropy properties of the single-mode binomial field interacting with the two entangled two-level
atoms. It is found that the different initial conditions lead to the different evolutions of entropy of the binomial field. 相似文献
964.
965.
Determination of Fatty Acid Methyl Esters in Biodiesel Produced from Yellow Horn Oil by LC 总被引:2,自引:0,他引:2
Yu-Jie Fu Yuan-Gang Zu Li-Li Wang Nai-Jing Zhang Wei Liu Shuang-Ming Li Su Zhang 《Chromatographia》2008,67(1-2):9-14
A simple and accurate HPLC method with refractive index detection was developed to determine the main fatty acid methyl esters
in biodiesel produced from yellow horn oil. Methyl linoleate, methyl linolenate, methyl arachidate, methyl stearate, methyl
palmitate and methyl oleate were separated on a HIQ SIL C18W column using methanol as mobile phase. The method has good repeatability
and precision, the intraday and interday RSD for both retention time and peak area was less than 3.2%. The LOD (S/N = 3) and
LOQ (S/N = 9) were less than 0.004 and 0.015 mg mL−1, respectively. 相似文献
966.
967.
968.
969.
Yaqin Fu Minghao Sun Yonggang Wu Zhishan Bo Dongge Ma 《Journal of polymer science. Part A, Polymer chemistry》2008,46(4):1349-1356
Conjugated polymers containing electron‐transporting, hole‐transporting, and blue light‐emitting units were synthesized by Suzuki polycondensation. These copolymers exhibited excellent thermal and optical stability. Optical investigation indicated that the incorporation of the spirobifluorene units in the polymer main chain could markedly increase the effective conjugation length of polymers. Electrochemical studies showed that the incorporation of spirobifluorene unit could raise the electrochemical stability and improve the electron‐ and hole‐injecting abilities. The electroluminescent results also showed that the introducing of spirobifluorene units could significantly improve the device performance. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1349–1356, 2008 相似文献
970.
Jianhua Liu Yusong Wang Qi Fu Xiangyang Zhu Wenfang Shi 《Journal of polymer science. Part A, Polymer chemistry》2008,46(4):1449-1459
A simple mathematic model for the free radical polymerization of chain transfer monomers containing both polymerizable vinyl groups and telogen groups was proposed. The molecular architecture of the obtained polymer can be prognosticated according to the developed model, which was validated experimentally by homopolymerization of 4‐vinyl benzyl thiol (VBT) and its copolymerization with styrene. The chain transfer constant (CT) of telogen group in a chain transfer monomer is considered to play an important role to determine the architecture of obtained polymer according to the proposed model, either in homopolymerization or copolymerization. A highly branched polymer will be formed when the CT value is around unity, while a linear polymer with a certain extent of side chains will be obtained when the CT value is much bigger or smaller than unity. The CT of VBT was determined to be around 15 by using the developed model and 1H NMR monitored experiments. The obtained poly(VBT) and its copolymers were substantiated to be mainly consisted of linear main chain with side branching chains, which is in agreement with the anticipation from the developed model. The glass transition temperature, number average molecular weight, and its distribution of those obtained polymer were primarily investigated. This model is hopefully to be used as a strategy to select appropriate chain transfer monomers for preparing hyperbranched polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1449–1459, 2008 相似文献