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Search Results: 1 - 10 of 106185 matches for " XU Shi-wei "
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Applying Importance-performance Analysis to Evaluate Logistics Service Quality for Online Shopping among Retailing Delivery
Yu-Kai Huang,Yi-Wei Kuo,Shi-Wei Xu
International Journal of Electronic Business Management , 2009,
Abstract: In the logistics system of electronic commerce, the major difference between Taiwan and other countries is the retailing delivery (RD) system. Delivering consistently good service quality is difficult but profitable for logistics organizations. This paper explores thestructure of logistic for RD service for electronic commerce. Drawing upon a sample of 135 users of retailing delivery and working within the framework of structural equation modeling (SEM), this study examines the relationships among the logistics service quality(LSQ), satisfaction and loyalty. Finally, this study used Importance-Performance analysis (IPA) to discuss the relations of level of customers’ expected logistics service quality and level of customers’ perceived logistics serviced quality, implications of these results for practice and research are provided.
Gamma-Ray Bursts: the Isotropic-Equivalent-Energy Function and the Cosmic Formation Rate
Shi-Wei Wu,Dong Xu,Fu-Wen Zhang,Da-Ming Wei
Physics , 2011, DOI: 10.1111/j.1365-2966.2012.21068.x
Abstract: Gamma-ray bursts (GRBs) are brief but intense emission of soft $\gamma-$rays, mostly lasting from a few seconds to a few thousand seconds. For such kind of high energy transients, their isotropic-equivalent-energy ($E_{\rm iso}$) function may be more scientifically meaningful when compared with GRB isotropic-equivalent-luminosity function ($L_{\rm iso}$), as the traditional luminosity function refers to steady emission much longer than a few thousand seconds. In this work we for the first time construct the isotropic-equivalent-energy function for a sample of 95 bursts with measured redshifts ($z$) and find an excess of high-$z$ GRBs. Assuming that the excess is caused by a GRB luminosity function evolution in a power-law form, we find a cosmic evolution of $E_{\rm iso}\propto(1+z)^{1.80^{+0.36}_{-0.63}}$, which is comparable to that between $L_{\rm iso}$ and $z$, i.e., $L_{\rm iso}\propto(1+z)^{2.30^{+0.56}_{-0.51}}$ (both $1\sigma$). The evolution-removed isotropic-equivalent-energy function can be reasonably fitted by a broken power-law, in which the dim and bright segments are $\psi(E_{\rm iso})\propto E_{\rm iso}^{-0.27\pm0.01}$ and $\psi(E_{\rm iso})\propto E_{\rm iso}^{-0.87\pm0.07}$, respectively ($1\sigma$). For the cosmic GRB formation rate, it increases quickly in the region of $0 \leq z \lesssim 1$, and roughly keeps constant for $1\lesssim z \lesssim 4$, and finally falls with a power index of $-3.80\pm2.16$ for $z\gtrsim 4$, in good agreement with the observed cosmic star formation rate so far.
The progress in phosphate remediation of heavy metal-contaminated soils
磷酸盐修复重金属污染土壤的研究进展

ZHOU Shi-Wei,XU Ming-Gang,
周世伟
,徐明岗

生态学报 , 2007,
Abstract: Phosphate has been identified as a cost-effective amendment to remediate heavy metal-contaminated soils. In this paper, research methods for phosphate remediation, reaction mechanisms between phosphate and heavy metals, and the potential risk due to excessive phosphate application were reviewed in detail. In addition, some problems and limitations were also discussed. Chemical extraction procedures, chemical equilibrium speciation models, and spectroscopic and microscopic techniques are main methods to investigate phosphate remediation. It is necessary to combine all techniques because of the limitation of every method. Phosphate-induced adsorption of heavy metals on contaminated soils, the formation of precipitates and/or minerals of heavy metal phosphate, and adsorption of heavy metals on phosphate surfaces are primary mechanisms for phosphate remediation. At present, it is difficult to effectively differentiate whether phosphate induced decrease in heavy metal availability is due to increased adsorption of metals or whether it is the result of precipitation or other fixation. Accordingly, it is more difficult to predict the long-term stability of phosphate remediation. As an amendment, phosphate is excessively applied to soils contaminated by heavy metals. There is probably some potential risk such as eutrophication of water bodies due to phosphorus leaching loss, the deficiency of medium- and micro-elements in plants caused by unbalance of nutrients, and soil acidification, etc. Thus, the species and rate of phosphoric fertilizers should be cautiously determined, with the optimum scheme where soluble phosphoric fertilizers are mixed with insoluble ones, or co-application of lime and phosphoric fertilizers. Finally, we emphasized the importance of quantitative assessment of reaction mechanisms and potential risk during phosphate remediation. Especially, one should pay more attention to the long-term solubility and mobility of stabilized heavy metals under the condition of continuous decrease in soil phosphate due to uptake by plant or other changes, and to phosphate remediation of field soils.
On the Entropy Preservation of Information Electromagnetic Leakage from CRT Visual Display Unit
CRT显示器信息电磁泄漏保熵性研究

Dong Shi-wei,Xu Jia-dong,
董士伟
,许家栋

电子与信息学报 , 2004,
Abstract: Considering CRT visual display unit and reconnaissance-receiving system as a communication system, this paper sets up two information source models and their corresponding information sink models of information's electromagnetic leakage from CRT visual display unit when image and text are displayed on the screen. Entropy preservation of the system is discussed combined with the concept of entropy loss rate of information source and entropy acquisition rate of information sink. A measure is put forward to ensure the information security of CRT visual display unit. The computational and experimental results show the consistance with the theoretical analysis.
Reexamination of constrains on the Maxwell-Boltzmann distribution by Helioseismology
Jian-jun He,Li-yong Zhang,Su-qing Hou,Shi-wei Xu
Physics , 2013, DOI: 10.1088/1674-1137/37/10/104001
Abstract: Nuclear reactions in stars occur between nuclei in the high-energy tail of the energy distribution and are sensitive to possible deviations from the standard equilibrium thermal-energy distribution, the well-known Maxwell-Boltzmann Distribution (\textsf{MBD}). In a previous paper published in Physics Letters 441B(1998)291, Degl'Innocenti {\it et al}. made strong constrains on such deviations with the detailed helioseismic information of the solar structure. With a small deviation parameterized with a factor exp$[{-\delta (E/kT)^2}]$, it was shown $\delta$ restricted between -0.005 and +0.002. These constrains have been carefully reexamined in the present work. We find that a normalization factor was missed in the previous modified \textsf{MBD}. In this work, the normalization factor $c$ is calculated as a function of $\delta$. It shows the factor $c$ is almost unity within the range 0$< \delta \leq$0.002, which supports the previous conclusion. However, it demonstrates that $\delta$ cannot take a negative value from the normalization point of view. As a result, a stronger constraint on $\delta$ is defined as 0$\leq \delta \leq$0.002. The astrophysical implication on the solar neutrino fluxes is simply discussed based on a positive $\delta$ value of 0.003. The reduction of the $^7$Be and $^8$B neutrino fluxes expected from the modified \textsf{MBD} can possibly shed alternative light on the solar neutrino problem. In addition, the resonant reaction rates for the $^{14}$N($p$,$\gamma$)$^{15}$O reaction are calculated with a standard \textsf{MBD} and a modified \textsf{MBD}, respectively. It shows that the rates are quite sensitive even to a very small $\delta$. This work demonstrates the importance and necessity of experimental verification or test of the well-known \textsf{MBD} at high temperatures.
Two Different Fermentation Techniques of Steriod 1,4-dehydrogenation and 11α-hydroxylation
甾体1,4-脱氢和11α-羟基化反应的两种不同微生物转化

XU Shi-Wei,XU Qing,FA You-Hua,
徐诗伟
,徐清,法幼华

生物工程学报 , 2000,
Abstract:
Two different fermentation techniques of steriod 1,4-dehydrogenation and 11 alpha-hydroxylation]
甾体1,4-脱氢和11α-羟基化反应的两种不同微生物转化

XU Shi-Wei,XU Qing,FA You-Hua,
徐诗伟
,徐清,法幼华

生物工程学报 , 2000,
Abstract: Two kinds of micro-organism, Arthrobacter sp. AX86(1,4-dehdrogenator) and Absidia sp. A28(11 alpha-hydroxylator) were used in this experiment. Two different fermentation techniques were performed to accomplish the multiple conversional reactions for producing 16 beta-methyl-11 alpha,17 alpha,21-trihydroxy-1,4-pregnadiene-3,20-dione(III) from 16 beta-methyl-3 beta,17 alpha,21-trihydroxy-5 alpha-pregnane-20-one-21-acetate(I): 1) To produce product(III) by means of a two-step fermentation method which were independently performed first by Arthrobacter and next by Absiaia, and 2) the product was obtained by a sequential fermentation system of aforesaid two micro-organisms in a single fermentor without isolation of the intermediates from the mixture. Our results showed that in both fermentation systems high yield of product was obtained. However, according to the technical simplicity, shorter duration of fermentation cycle and efficient yield of product, the second method is better than the first one.
Gastroesophageal reflux in cirrhotic patients without esophageal varices
Jun Zhang, Pei-Lin Cui, Dong Lv, Shi-Wei Yao, You-Qing Xu, Zhao-Xu Yang
World Journal of Gastroenterology , 2011,
Abstract: AIM: To evaluate the esophageal motility and abnormal acid and bile reflux incidence in cirrhotic patients without esophageal varices (EV).METHODS: Seventy-eight patients with liver cirrhosis without EV confirmed by upper gastroesophageal endoscopy and 30 healthy control volunteers were prospectively enrolled in this study. All the patients were evaluated using a modified protocol including Child-Pugh score, upper gastrointestinal endoscopy, esophageal manometry, simultaneous ambulatory 24-h esophageal pH and bilirubin monitoring. All the patients and volunteers accepted the manometric study.RESULTS: In the liver cirrhosis group, lower esophageal sphincter pressure (LESP, 15.32 ± 2.91 mmHg), peristaltic amplitude (PA, 61.41 ± 10.52 mmHg), peristaltic duration (PD, 5.32 ± 1.22 s), and peristaltic velocity (PV, 5.22 ± 1.11 cm/s) were all significantly abnormal in comparison with those in the control group (P < 0.05), and LESP was negatively correlated with Child-Pugh score. The incidence of reflux esophagitis (RE) and pathologic reflux was 37.18% and 55.13%, respectively (vs control, P < 0.05). And the incidence of isolated abnormal acid reflux, bile reflux and mixed reflux was 12.82%, 14.10% and 28.21% in patients with liver cirrhosis without EV.CONCLUSION: Cirrhotic patients without EV presented esophageal motor disorders and mixed acid and bile reflux was the main pattern; the cirrhosis itself was an important causative factor.
Preparation of Nanometer Calcium Carbonate by Multistage Spray Carbonation
多级喷雾碳化法制备纳米碳酸钙工艺研究

XU Wang-Sheng,HE Bing-Zhong,JIN Shi-Wei,XUAN Ai-Guo,
徐旺生
,何秉忠,金士威,宣爱国

无机材料学报 , 2001,
Abstract: The preparation process of nanometer calcium carbonate(CaCO3) by multistage spray carbonation was studied. The effects of the conditions of spray carbonation and additive dosage on the average particle size of nanometer CaCO3 were discussed systematically. The primary particle size of carbonated sediment was about 30nm by vacuum desiccation. Then the active nanometer CaCO3 particles ranged from 30nm to 40nm were obtained by means of surfaction.
Quality Control Schemes and Its Application to Automatic Surface Weather Observation System
地面自动站资料质量控制方案及应用

TAO Shi-wei,ZHONG Qi-qin,XU Zhi-fang,HAO Min,
陶士伟-
,仲跻芹,徐枝芳,郝民

高原气象 , 2009,
Abstract: 为满足精细、 短时天气预报的需求, 我国地面自动站(AWS)观测系统的建设日趋完善。AWS资料在数值预报系统中没得到充分使用的原因之一是AWS观测资料的特殊性及数值预报系统缺少有效针对AWS观测资料的质量控制(QC)方案。本文AWS QC方案在参考国际先进的AWS QC方案基础上, 根据我国地面自动站的特点和数值天气预报模式对地面资料应用的要求设计。其目的是解决AWS观测资料在数值预报中应用的质量问题。本方案采用多种质量控制技术, 其中包括台站气候极值检查、 要素间一致性检查、 时间一致性检查、 持续性检查、 背景场一致性检查、 空间一致性检查、 综合决策算法、 自动统计评估反馈技术。本文从检查方法对错误资料的敏感度和确定性进行理论分析表明, 该方案具有更强的敏感度和确定性。将该方案应用于北京地区2006年8月AWS实际观测资料检验, 结果表明, 该方案能有效地识别观测资料中存在明显错误的资料, 有效地为地面自动站资料在数值模式中的应用提供客观质量依据。
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