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Search Results: 1 - 10 of 124379 matches for " Zhang-ji YE "
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防污剂在溶胀聚合物中扩散的模拟研究
Release of the antifoulant in equilibrium swollen polymer: molecular dynamics simulation

程栋材,黄志雄,任润桃,王晶晶,叶章基,张亮,王跃平
Dong-cai CHENG
,Zhi-xiong HUNAG,Run-tao REN,Jing-jing WANG,Zhang-ji YE,Liang ZHANG,Yue-ping WANG

- , 2018, DOI: 10.6040/j.issn.1671-9352.0.2018.031
Abstract: 利用Materials Studio软件进行分子动力学模拟研究平衡溶胀结构聚合物。调查溶胀前后聚合物玻璃化温度,水与链段在平衡溶胀态下的动力学、不同含水量下水分子的局部动力学和防污剂分子扩散行为,从分子角度解释包覆防污剂的受控释放机制。模拟发现处于平衡溶胀态下, 3种P(MMA-co-n-BMA)玻璃化温度分别降低21.72、17.27、14.40 K,水的动力学性质接近本体水,并且高于聚合物链段2个指数;溶胀聚合物处于橡胶态时,防污剂的有效扩散明显增加。结果表明,聚合物的含水量与玻璃化温度是控制防污剂分子扩散的关键因素。
To investigate the release of the antifouling molecules in equilibrium swelling (ES) states, molecular dynamics (MD) simulation was performed to analyze the diffusion of 4, 5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) molecule in P(MMA-co-n-BMA) immersed in water. The glass transition temperature (Tg) was simulated in the dry and equilibrium swelling states, and the dynamics of water and the pendant groups in the ES state were investigated, as well as the influence of water content on the local dynamics of water. The diffusion mechanisms of DCOIT were also analyzed. Tg values of three P(MMA-co-n-BMA)s in the ES state are from 14.84, 17.27 K to 21.73 K lower than in the dry state. Water has the higher mobility than the pendant groups by approx. 2 orders of magnitude in ES systems and has dynamic properties on the same level as those of bulk water. The diffusion of a large-mass penetrant can be controlled effectively with water and Tg as the crucial factors, and the diffusion ability of DCOIT is significantly enhanced when the swollen matrix is in the rubbery state.
Molecular Clouds in the North American and Pelican Nebulae: Structures
Shaobo Zhang,Ye Xu,Ji Yang
Physics , 2013, DOI: 10.1088/0004-6256/147/3/46
Abstract: We present observations of 4.25 square degree area toward the North American and Pelican Nebulae in the $J = 1-0$ transitions of $^{12}$CO, $^{13}$CO, and C$^{18}$O. Three molecules show different emission area with their own distinct structures. These different density tracers reveal several dense clouds with surface density over 500 $M_\odot$ pc$^{-2}$ and a mean H$_2$ column density of 5.8, 3.4, and 11.9$\times10^{21}$ cm$^{-2}$ for $^{12}$CO, $^{13}$CO, and C$^{18}$O, respectively. We obtain a total mass of $5.4\times10^4 M_\odot$ ($^{12}$CO), $2.0\times10^4 M_\odot$ ($^{13}$CO), and $6.1\times10^3 M_\odot$ (C$^{18}$O) in the complex. The distribution of excitation temperature shows two phase of gas: cold gas ($\sim$10 K) spreads across the whole cloud; warm gas ($>$20 K) outlines the edge of cloud heated by the W80 H II region. The kinetic structure of the cloud indicates an expanding shell surrounding the ionized gas produced by the H II region. There are six discernible regions in the cloud including the Gulf of Mexico, Caribbean Islands and Sea, Pelican's Beak, Hat, and Neck. The areas of $^{13}$CO emission range within 2-10 pc$^2$ with mass of (1-5)$\times10^3 M_\odot$ and line width of a few km s$^{-1}$. The different line properties and signs of star forming activity indicate they are in different evolutionary stages. Four filamentary structures with complicated velocity features are detected along the dark lane in LDN 935. Furthermore, a total of 611 molecular clumps within the $^{13}$CO tracing cloud are identified using the ClumpFind algorithm. The properties of the clumps suggest most of the clumps are gravitationally bound and at an early stage of evolution with cold and dense molecular gas.
Psychosocial factors underlying physical activity
Juan Zhang, Susan E Middlestadt, Cheng-Ye Ji
International Journal of Behavioral Nutrition and Physical Activity , 2007, DOI: 10.1186/1479-5868-4-38
Abstract: A theory-based qualitative study using a self-completion elicitation was conducted with 155 students from two middle schools in Beijing, China. Following the Theory of Planned Behavior, six open-ended questions asked students for their perceptions about performing physical activity at least 60 minutes each day: advantages of participating in physical activity; disadvantages of doing so; people who approve of participation; people who disapprove; things that make it easy; and things that make it hard. Content analysis revealed categories of salient consequences, reference groups, and circumstances.While the three most frequently mentioned advantages elicited from the students were physical health consequences (e.g., will strengthen my body (58.7%)), four of the salient advantages were not (e.g., will improve my grades (12.2%)). Parents were the most frequently mentioned social referent (42.6% as approving; 27.7% as disapproving) when students were asked who might approve or disapprove of their participation. Circumstances perceived to hinder daily physical activity included having too many assignments and not having enough time.While many of the beliefs about physical activity elicited from this study were similar to those found with students from England and the US, several were unique to these students from Beijing. The results of this qualitative research suggest that interventions to encourage physical activity among middle school students should address: perceived consequences of physical activity on academic achievement and other factors beyond physical health; barriers of not having enough time and having too many assignments perceived to hinder frequent physical activity; and parental approval. More rigorous research on psychosocial determinants with close-ended items developed from these open-ended data and with larger sample sizes of students is necessary. Research with parents and school staff will be needed to understand the perceptions of these stakehold
Cross-Modal Learning via Pairwise Constraints
Ran He,Man Zhang,Liang Wang,Ye Ji,Qiyue Yin
Computer Science , 2014,
Abstract: In multimedia applications, the text and image components in a web document form a pairwise constraint that potentially indicates the same semantic concept. This paper studies cross-modal learning via the pairwise constraint, and aims to find the common structure hidden in different modalities. We first propose a compound regularization framework to deal with the pairwise constraint, which can be used as a general platform for developing cross-modal algorithms. For unsupervised learning, we propose a cross-modal subspace clustering method to learn a common structure for different modalities. For supervised learning, to reduce the semantic gap and the outliers in pairwise constraints, we propose a cross-modal matching method based on compound ?21 regularization along with an iteratively reweighted algorithm to find the global optimum. Extensive experiments demonstrate the benefits of joint text and image modeling with semantically induced pairwise constraints, and show that the proposed cross-modal methods can further reduce the semantic gap between different modalities and improve the clustering/retrieval accuracy.
Residue analysis and dissipation of a new fungicide 2-allylphenol in tomato
HU Ji-ye,ZHANG Wen-ji,LI Jian-zhong,
HU Ji-ye
,ZHANG Wen-ji,LI Jian-zhong

环境科学学报(英文版) , 2005,
Abstract: The method of residue analysis of a new synthesized fungicide 2-allylphenol was studied by simulating the active compound structure in Gingko tree (Gingko biloba L.) and its dissipation rate and terminal residue levels in tomato under field condition. Residues of 2-allylphenol were extracted from tomato matrix with acetone, purified by liquid-liquid extraction and Florisil cartrieges, and then determined by HPLC with UV-detector. The minimum detectable amount of 2-allylphenol was 3 x 10(-9) g, the minimum detectable concentration of 2-allylphenol in the samples of tomato were 0.01 mg/kg. The ranges of average recoveries and coefficient variation of the method were 87.7%-90.2% and 1.25%-2.06%, respectively. The dissipation rate and terminal residue levels in tomato were determined with the method described above. The results showed that the half-life of 2-allylphenol in tomato was 6.37 d, and 2-allylphenol declined with 82.6% of the initial deposit remaining in tomato at harvest. The terminal residue levels in tomato were 0.15 mg/kg and 0.20 mg/kg following the recommended doses and time intervals.
Synovial sarcoma of the buttocks presenting with a non-healing wound and rapid progression after local resection: a case report
Hai-Yan Zhang, Ye Feng, Zhu Zhang, Ge Gao, Ji-Sheng Zhao
World Journal of Surgical Oncology , 2012, DOI: 10.1186/1477-7819-10-125
Abstract:
Effects of CeO2 and CaO on properties of Ni/MgO-Al2O3 catalysts for partial oxidation of methane to syngas
CeO2、CaO助剂对甲烷部分氧化制合成气Ni/MgOAl2O3催化剂结构和性能的影响

QIU Ye-jun,CHEN Ji-xiang,ZHANG Ji-yan,
邱业君
,陈吉祥,张继炎

燃料化学学报 , 2007,
Abstract: The effects of CeO2 and/or CaO as promoters on the physico-chemical properties and the catalytic performance over Ni/MgO-Al2O3 catalyst for partial oxidation of methane to syngas were studied by means of BET,XRD,H2-TPR,TEM and reaction activity evaluation.Compared with the catalyst without promoters,the catalyst promoted by CeO2 or CaO alone exhibited better reducibility of nickel species,and the one promoted by CaO showed better catalytic activity.When both of CeO2 and CaO were added to modify the Ni/MgO-Al2O3 catalyst,an obvious synergetic effect between CeO2 and CaO were detected.It was deduced that the formation of CaO-CeO2 solid solution could result in a better dispersion of active nickel species and promote the conversion of Ce4 to Ce3 species,thus reduced the size of nickel crystallites efficiently.Better oxygen adsorption ability,more oxygen-vacant sites and more migration of oxygen anions could benefit oxygen exchange between NiO and CeO2.The above effects were contributed to higher CH4 conversion,CO selectivity and H2 selectivity over the catalyst promoted with CeO2 and CaO in the partial oxidation of methane.
Effects of MgO promoter on properties of Ni/Al2O3 Catalysts for partial oxidation of methane to syngas
MgO助剂对甲烷部分氧化Ni/Al2O3催化剂结构和性能的影响

QIU Ye-jun,CHEN Ji-xiang,ZHANG Ji-yan,
邱业君
,陈吉祥,张继炎

燃料化学学报 , 2006,
Abstract: The effects of MgO promoter on the physico-chemical properties and the catalytic performance of Ni/ Al2O3 catalysts for partial oxidation of methane to syngas were studied by BET, XRD, HE-TPR, TEM and reaction activity evaluation. It was found that MgO promoter benefited to the uniformity of nickel species on the catalysts, inhibited the formation of NiAl2O4 spinel and improved the interaction between nickel species and the support. This result was related to the formation of NiO-MgO solid solution and MgAl2O4 spinel. Moreover, for the catalysts with proper amount of MgO promoter, the dispersion of nickel species was enhanced, and thus their catalytic performance for methane partial oxidation to syngas was improved. However, excessive MgO promoter exerted a negative effect on the catalyst performance. In addition, the basicity of MgO promoted the reverse watergas shift reaction, which led to the increase of CO selectivity and the decrease of HE selectivity. The suitable content of MgO promoter in Ni/Al2O3 catalyst was about 7%.
Image Retrieval Method Using Top-surf Descriptor
Ye Ji
Computer Science , 2011,
Abstract: This report presents the results and details of a content-based image retrieval project using the Top-surf descriptor. The experimental results are preliminary, however, it shows the capability of deducing objects from parts of the objects or from the objects that are similar. This paper uses a dataset consisting of 1200 images of which 800 images are equally divided into 8 categories, namely airplane, beach, motorbike, forest, elephants, horses, bus and building, while the other 400 images are randomly picked from the Internet. The best results achieved are from building category.
Movement Protein Pns6 of Rice dwarf phytoreovirus Has Both ATPase and RNA Binding Activities
Xu Ji, Dan Qian, Chunhong Wei, Gongyin Ye, Zhongkai Zhang, Zujian Wu, Lianhui Xie, Yi Li
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024986
Abstract: Cell-to-cell movement is essential for plant viruses to systemically infect host plants. Plant viruses encode movement proteins (MP) to facilitate such movement. Unlike the well-characterized MPs of DNA viruses and single-stranded RNA (ssRNA) viruses, knowledge of the functional mechanisms of MPs encoded by double-stranded RNA (dsRNA) viruses is very limited. In particular, many studied MPs of DNA and ssRNA viruses bind non-specifically ssRNAs, leading to models in which ribonucleoprotein complexes (RNPs) move from cell to cell. Thus, it will be of special interest to determine whether MPs of dsRNA viruses interact with genomic dsRNAs or their derivative sRNAs. To this end, we studied the biochemical functions of MP Pns6 of Rice dwarf phytoreovirus (RDV), a member of Phytoreovirus that contains a 12-segmented dsRNA genome. We report here that Pns6 binds both dsRNAs and ssRNAs. Intriguingly, Pns6 exhibits non-sequence specificity for dsRNA but shows preference for ssRNA sequences derived from the conserved genomic 5′- and 3′- terminal consensus sequences of RDV. Furthermore, Pns6 exhibits magnesium-dependent ATPase activities. Mutagenesis identified the RNA binding and ATPase activity sites of Pns6 at the N- and C-termini, respectively. Our results uncovered the novel property of a viral MP in differentially recognizing dsRNA and ssRNA and establish a biochemical basis to enable further studies on the mechanisms of dsRNA viral MP functions.
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