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Articles
by
Rui Zhang |
Total Records (
11 ) for
Rui Zhang |
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Xiuzhu Yu
,
Yandie Yang
,
Lirong Xu
,
Zhong Zhao
and
Rui Zhang
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Objective: Glycerolysis of rapeseed oil was catalyzed with lipozyme TL IM lipase to produce diacylglycerol (DG). Methodology: To optimize DG yield, the effect of five-level four factors and their reciprocal interactions on product yield through Response Surface Methodology (RSM) was evaluated. Thirty individual experiments were performed to investigate reaction temperature, reaction time, enzyme loading and substrate mass ratio. Results: Well-fitting model was established through multiple regression with backward elimination for DG yield (R2 = 0.8388). The optimal conditions established include 60°C reaction temperature, 8 h reaction time, 16% enzyme loading and 0.07 substrate mass ratio (glycerol to rapeseed oil), resulting to 82.4% DG yield. Conclusion: The experimental data showed good validation with the predicted value. Transesterification of rapeseed oil and glycerol was monitored by using Fourier transform infrared (FT-IR) spectroscopy. |
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Qin Wanga
,
Xiaoyi Liang
,
Wenming Qiao
,
Chaojun Liu
,
Xiaojun Liu
,
Rui Zhang
and
Licheng Ling
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Polystyrene-based activated carbon spheres (PACS) were modified with either air, HNO3, (NH4)2S2O8, H2O2 or H2 to improve their adsorption properties of dibenzothiophene (DBT). The texture and surface chemistry of PACS were characterized by N2 adsorption, scanning electron microscopy (SEM), temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), acid–base titration and elemental analysis. The results showed that HNO3 and (NH4)2S2O8 treatments introduced large amount of acidic groups such as carboxylic, lactones and anhydride groups, while air and H2O2 had relatively mild effects and introduced a small quantity of phenol, carbonyl and ether groups. In the HNO3 treatment, the acidic groups might be fixed on the internal and external surface of PACS, which may act as active sites of adsorption, resulting in increase of the adsorption amount by 45%. Whereas H2O2 and (NH4)2S2O8 treatments might fix more oxygen-containing groups on the external surface, which may hinder DBT molecule enter into micropores, leading to rather lower adsorption capacity with the extent of oxidation. So, the concentration, distribution and types of the acidic functional groups are responsible for the removal of DBT. |
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Jinping Liu
,
Yi Zhang
,
Lin Lan
,
Rui Zhang
and
Feifei Liu
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Local brand prejudice is a significant and widespread proposition in China. Chinese media play the part of highlighting the local brand quality crisis or activating the local brand bias deliberately or accidentally. This study takes the Chongqing Wal-mart food safety event reported by Chinese media as an example. It makes the text analysis with frame theory on the media frame, subject discourse-power and agenda setting. And it reveals the deficiency of national interest standard and self-consciousness of Chinese media when they reported the negative event of foreign brand. It confirms the framing effect of local brand prejudice formed by Chinese media. |
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Yi Zhang
,
Jinping Liu
,
Lin Lan
,
Rui Zhang
and
Feifei Liu
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Business practice shows that brand in essence is a kind of "commitment" which creates value for stakeholders and can get value from it. At present, most researches explore the consumption psychology and behavior from the view of brand loyal (or purchase intention) and pay the less attention to the brand value commitment. Even in the few related studies, they are qualitative ones. Therefore, by virtue of the Organization Commitment Theory and Commitment Foci, this study divides the brand value commitment into Attitude Commitment by the way of organizational behavior and Behavior Commitment by the way of social psychology. Attitude commitment includes organizational commitment, affective commitment, quality commitment, economic commitment and relationship commitment. Behavioral commitment includes purchase commitment, reputation commitment, tolerance commitment and continuance commitment. By questionnaires, this study analyzes the influence of consumer brand attitude commitment on their behavior commitment. And it confirms that consumer brand attitude commitment have a significant positive impact on their purchase commitment, public praise commitment and continuance commitment; while the organizational commitment, affective commitment, quality commitment and relationship commitment have significant positive impacts on consumer brand behavior commitment. |
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Yi Zhang
,
Jinping Liu
,
Min Zhou
,
Feifei Liu
,
Lin Lan
and
Rui Zhang
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A large body of evidence has demonstrated that COO stereotype
is a typical cognitive bias of Chinese consumers, how to inhibit the stereotype
is an important research proposition. This study tends to choose information
of two product-related attributes and information of two non-product-related
attributes through reports materials of negative information of foreign brands
in media in recent years to constitute four experimental groups. It finds that
the negative information involving quality and price profiteering is of significant
inhibition on quality evaluation, attitude preference and purchase intention
of subjects on specific foreign brands while the negative information involving
commercial bribery is not of significant inhibition, which shows that the inhibition
on specific foreign brand preference by negative information of foreign brands
is related to differences of product attributes. The inhibition on subjects
quality evaluation, attitude preference and purchase intention of abstract foreign
brands by negative information involving food quality is significantly higher
than by information of notebook quality, price profiteering and commercial bribery,
which shows food safety is of the highest accessibility. Meanwhile, the quality
evaluation, attitude preference and purchase intention of specific foreign brands
by subjects are lower than those of specific local brands, which shows a significant
inhibition on foreign brand preference and local brand bias by negative information
of foreign brands. |
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Yan Zhang
,
Qingzhong Li
,
Rui Zhang
and
Peiguang Lin
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With the fast increasing number of Web databases (WDBs), it
is core issue in the study of Web data integration that we should select the
most appropriate composition of databases to query and obtain more targeted
data at a smaller cost. In this study, in order to reduce redundant data from
different sources, we propose a novel method of Web databases redundancy computing
to select proper Web data sources for given keywords. To solve the problem,
we propose a web database feature representation model, and based on sample
data from the sources, we put forward the deep web redundancy computing method
considering three different data types: text attribute, numeric attribute and
categorical attribute. Experiments show that this method can achieve the desired
objectives and can meet the demand to the integrated system very well. |
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Zhibin Zeng
and
Rui Zhang
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Nonlinearity of power amplifier always results in spectrum spreading on input signal. When using digital predistortion technology to compensate power amplifier's nonlinearity, the required sampling frenquence for the output signal of amplifier is times of the original signal. According to the undersampling digital predistortion method based on Zhu Generalized Sampling Theorem, the amplifier output signal can be sampled as the sampling frequency of original baseband signal Nyquist rate. Using the undersampling digital predistortion method, the digital predistortion performance of non-memory power amplifier is satisfactory. But for amplifier with significant memory effect, the digital predistortion performance is worsened in comparison to amplifier with non-memory effect. Furthermore it is poorer than that of oversampling. Simulations show that the higher the sampling frequency, the better the digital predistortion performance. As for engineering application, if the requirements of digital predistortion performance are met, a sampling frequency should be chosen as low as possible for cost reduction. |
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Yuxiang Wei
,
Changmei Yang
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Baojun Wei
,
Jie Huang
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Lunan Wang
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Shuang Meng
,
Rui Zhang
and
Jinming Li
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RNase-resistant, noninfectious virus-like particles containing exogenous RNA sequences (armored RNA) are good candidates as RNA controls and standards in RNA virus detection. However, the length of RNA packaged in the virus-like particles with high efficiency is usually less than 500 bases. In this study, we describe a method for producing armored L-RNA. Armored L-RNA is a complex of MS2 bacteriophage coat protein and RNA produced in Escherichia coli by the induction of a two-plasmid coexpression system in which the coat protein and maturase are expressed from one plasmid and the target RNA sequence with modified MS2 stem-loop (pac site) is transcribed from another plasmid. A 3V armored L-RNA of 2,248 bases containing six gene fragments—hepatitis C virus, severe acute respiratory syndrome coronavirus (SARS-CoV1, SARS-CoV2, and SARS-CoV3), avian influenza virus matrix gene (M300), and H5N1 avian influenza virus (HA300)—was successfully expressed by the two-plasmid coexpression system and was demonstrated to have all of the characteristics of armored RNA. We evaluated the 3V armored L-RNA as a calibrator for multiple virus assays. We used the WHO International Standard for HCV RNA (NIBSC 96/790) to calibrate the chimeric armored L-RNA, which was diluted by 10-fold serial dilutions to obtain samples containing 106 to 102 copies. In conclusion, the approach we used for armored L-RNA preparation is practical and could reduce the labor and cost of quality control in multiplex RNA virus assays. Furthermore, we can assign the chimeric armored RNA with an international unit for quantitative detection. |
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Deliang Chen
,
Hejing Wen
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Huimin Chen
,
Hailong Wang
,
Rui Zhang
,
Hongliang Xu
,
Daoyuan Yang
and
Hongxia Lu
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The paper described a novel approach toward WO3 nanocrystals by pyrolytically decomposing tungstate-based inorganic–organic hybrid nanobelts in air at 500–600 °C for 2 h. The above-mentioned hybrid nanobelts were derived via a reaction of layered H2W2O7·xH2O and n-octylamine in a reverse-micelle-like medium (H2W2O7·xH2O/n-octylamine/heptane). The as-obtained WO3 nanocrystals and their intermediate products were characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM & FE-SEM), thermoanalysis (TG–DSC), Fourier-transform infrared spectra (FT/IR), UV–vis absorption and X-ray photoelectron spectroscopy (XPS). The as-obtained WO3 nanocrystals had an apparent size of 20–50 nm, and took on a loose-aggregate-like morphology. The WO3 nanocrystals derived via the pyrolytic decomposition process were almost separated from each other and could be redispersed readily, while the WO3 nanocrystals obtained by the conventional acid-precipitation process tightly agglomerated into large particles with apparent sizes of several micrometers, without redispersibility even under an intense sonication treatment. |
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Ning ZHANG
,
Xing- Dong HE
,
Yu-Bao GAO
,
Yong- Hong LI
,
Hai-Tao WANG
,
Di MA
,
Rui ZHANG
and
S. YANG
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Little attention has been paid to the role of soil organic matter (OM) in the formation of pedogenic carbonate in desert soils. The relationships among soil OM, soil dehydrogenase activity (DHA), and soil CaCO3 inaplantcommunity dominated by Artemisia ordosica, located on the eastern boundary of Tengger Desert in the Alxa League, Inner Mongolia, China, were studied to understand whether OM was directly involved in the formation of pedogenic carbonate. The results showed that DHA and CaCO3 positively correlated with OM content, and DHA, OM, and CaCO3 were correlated with each other in their spatial distribution, indicating that abundant OM content contributed to the formation of CaCO3. Therefore, the formation of pedogenic CaCO3 was a biotic process in the plant community dominated by A. ordosica. |
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Ling Zhao
,
Kaiyu Wang
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Qingjiao Liao
,
Rui Zhang
and
Wei Zhang
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In order to maximize the yield of polysaccharides of Catathelasma ventricosum, response surface methodology was applied to optimize the extraction conditions (extraction temperature, ratio of water to raw material and extraction time) of polysaccharides from the fruiting bodies of Catathelasma ventricosum. A box-behnken design was used for experimental design and analysis of the results to obtain the optimal processing parameters. Among the three extraction parameters, the extraction temperature was the most significant factor to affect the yield of polysaccharides from Catathelasma ventricosum. A mathematical model with high determination coefficient was gained and could be employed to optimize polysaccharides extraction and the optimal conditions were extraction temperature 100°C, ratio of water to raw material 22.78:1, extraction time 3.66 h. Under these conditions, the experimental yield of polysaccharide was 6.47±0.14% which was close to the predicted value. |
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