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Strongly Approximative Similarity of Operators

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Acta Mathematica Sinica,English Series 2009年第6期25卷 923-930页

作者： You qing ji Sen ZHU Department of Mathematics Jilin University Changchun 130012 P. R. China Institute of Mathematics Jilin University Changchun 130012 P. R. China

Two operators A, B ∈ B（H） are said to be strongly approximatively similar, denoted by A -sas B, if （i） given ε 〉 0, there exist Ki ∈ B（H） compact with ｜｜Ki｜｜〈ε（i = 1,2） such that A＋K1 and B ＋ K2 are similar; （ii） σ0（A） = σ0（B） and dim H（λ; A） = dim H（λ; B） for each λ ∈ σ0（A）. In this paper, we prove the following result. Let S,T ∈ B（H） be quasitriangular satisfying：（i） σ（T） = σ（S） = σw（S） is connected and σe（S） = σlre（S）; （ii） ρs-F（S） ∩ σ（S） consists of at most finite components and each component Ω satisfies that Ω = int Ω, where int Ω is the interior of Ω. Then, S -sas T if and only if S and T are essentially similar.

关键词： compact operator quasitriangular operator Cowen-Douglas operator essentially similar

Contemporary art casting's education in Guangdong

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China Foundry 2012年第1期9卷 1-5页

作者： ji qing Wu Chunmiao School of Mechanical&Automotive Engineering South China University of TechnlogyGuangzhou 510640GuangdongChina

Based on the practical experience of establishing three art casting laboratories in three different colleges of Guangdong,this paper focuses on the development of contemporary art casting's *** analyzing the reason for the shortage of professionals nowadays and the characteristics of modern foundry industry in the Pearl River Delta,the authors try to find out what kind of knowledge structures a modern foundry industry professional should ***,from the viewpoint of education,the authors introduce how to combine the art casting laboratory and the creative art casting course as a new teaching pattern,on the one hand,to attract more students to study casting technology,on the other hand,to train them to be qualified professionals for the modern foundry industry.

关键词： art casting education Guangdong

Preparation　of　Homocitrate　using　a　Modified　Method

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Chemical Research in Chinese Universities 1998年第1期14卷 93-95页

作者： Li, Zeng-chun Xu, ji-qing Inner Mongolia Natl Teachers Coll Dept Chem Tongliao 028043 Peoples R China jilin Univ Dept Chem Changchun 130023 Peoples R China

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ＰｒｅｐａｒａｔｉｏｎｏｆＨｏｍｏｃｉｔｒａｔｅｕｓｉｎｇａＭｏｄｉｆｉｅｄＭｅｔｈｏｄＬＩＺｅｎｇ－ｃｈｕｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＩｎｎｅｒＭｏｎｇｏｌｉａＮａｔｉｏｎａｌＴｅａｃｈｅｒｓＣｏｌｌｅｇｅ，Ｔｏｎｇｌｉａｏ，０...

关键词： Preparation using Modified Homocitrate Method

Pyrolysis of rice husk and sawdust for liquid fuel

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Journal of Environmental Sciences 2006年第2期18卷 392-396页

作者： ZHU Xi-feng ZHENG ji-lu GUO qing-xiang ZHU qing-shi Biomass Clean Energy Laboratory University of Science and Technology of China Hefei-230026 China

The paper is focused on studying how to convert rice husk and sawdust into liquid fuel. Rice husk, sawdust and their mixture were pyrolyzed at the temperature between 420℃ and 540℃, and the main product of liquid fuel was obtained. The experimental result showed that the yield of liquid fuel heavily depended on the kind of feedstock and pyrolysis temperature. In the experiments, the maximum liquid yields for rice husk, sawdust and their mixture were 56% at 465 ℃, 61% at 490℃ and 60% at 475℃ respectively. Analysis with GC-MS and other apparatus indicated that the liquid fuel is a complicated organic compound with low caloric value and can be directly used as fuel oil without any up-grading. As a crude oil, the liquid fuel can be refined to be vehicle oil.

关键词： solid organic waste rice husk sawdust pyrolysis liquid fuel

Query routing mismatch alleviation architecture for P2P file lookup in MANETs

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The Journal of China Universities of Posts and Telecommunications 2011年第4期18卷 111-117页

作者： MEI jing-qing ji Hong LI Yi Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

A cross-layer optimized query routing mismatch alleviation （QRMA） architecture is proposed to mitigate the problem of query routing mismatch （QRM） phenomenon between the structured peer to peer （P2P） overlay and the routing layer in mobile Ad-hoc networks （MANETs）, which is an important issue that results in the inefficiency of lookup process in the system. Explicated with the representative Chord protocol, the proposal exploits the information of topologic neighbors in the routing layer of MANETs to find if there is any optimized alternative next hop in P2P overlay during conventional lookup progress. Once an alternative next hop is detected, it will take the shortcut to accelerate the query procedure and therefore alleviate the QRM problem in scalable MANETs without any assistance of affiliation equipments such as GPS device. The probability of finding out such an alternative node is formulated and the factors that could increase the chance are discussed. The simulation results show that the proposed architecture can effectively alleviate the QRM problem and significantly improve the system performance compared with the conventional mechanism.

关键词： query routing mismatch P2P overlay Chord MANETs

Cross-layer optimized Chord protocol for separated ring convergence in MANET

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The Journal of China Universities of Posts and Telecommunications 2009年第4期16卷 84-90页

作者： MEI jing-qing ji Hong LI Ting Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

An optimized Chord protocol is proposed to solve the convergence problem for separated Chord rings over mobile Ad-hoc networks （MANETs）. This protocol exploits the information of topological neighbors in routing layer by utilizing a cross-layer design, and periodically detects whether there is any neighbor node that belongs to an alien Chord ring by sending detecting packets. The detection will be confirmed and then the corresponding predecessor node will be found out to initialize convergence of the Chord rings. Theoretical analysis and experiment results show that the proposed algorithm can detect separated Chord rings and implement the convergence process efficiently, and that a significant improvement in the successful lookup ratio is also achieved at an acceptable overhead for the system maintenance. Moreover, the proposed protocol can ensure the stability and scalability of the system.

关键词： convergence Chord mobile Ad-hoc network (MANET) cross-layer

A THEORETIC METHOD TO PREDICT POLYMER SOLUBILITY PARAMETERS

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Chinese Journal of Polymer Science 2007年第2期25卷 203-206页

作者： qing ji Bao-fu Qiao De-lu Zhao State Key Laboratoryof Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

A partition function and a complete thermodynamic description for pure polymer fluids have been investigated based on a self-avoid-walk lattice model. Caused by the introduction of Gibbs distribution into the Flory-Huggins theory, the partition function and the thermodynamic description depicted their dependence on temperature well. In the present study, we applied the theory to calculate polymer solubility parameters. The polymer solubility parameters predicted by our theory are well consistent with the experiment values.

关键词： Polymer Solubility parameters Gibbs distribution.

Snow features on sea ice in the western Arctic Ocean during summer 2016

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International Journal of Digital Earth 2021年第10期14卷 1397-1410页

作者： qing ji Xiaoping Pang Xi Zhao Ruibo Lei Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhanPeople’s Republic of China Polar Research of China ShanghaiPeople’s Republic of China

Arctic sea ice and its snow cover are important components of the cryosphere and the climate system.A series of in situ snow measurements were conducted during the seventh Chinese Arctic expedition in summer 2016 in the western Arctic *** this study,we made an analysis of snow features on Arctic sea ice based on in situ observations and the satellite-derived parameter of snow grain size from MODIS spectral reflectance *** indicate that snow depth on Arctic sea ice varied between 19 and 241 mm,with a mean value of 100 *** mean density of the snow was 340.4 kg/m^(3)during the expedition,which was higher than that reported in previous *** measurements revealed that a depth hoar layer was widely developed in the snow,accounting for 30%∼50%of the total snow *** equivalent snow grain size was small on the surface and large at the bottom in snow *** average relative error between MODIS-derived snow grain size and in situ measured surface snow grain size is 14.6%,indicating that remote sensing is a promising method to obtain large-scale information of snow grain size on Arctic sea ice.

关键词： Snow cover snow grain size snow stratigraphy remote sensing

Molecular dynamics simulations of the hydration of poly(vinyl methyl ether):Hydrogen bonds and quasi-hydrogen bonds

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Science China Chemistry 2008年第8期51卷 736-742页

作者： WU RongLiang ji qing KONG Bin YANG XiaoZhen Beijing National Laboratory for Molecular Sciences(BNLMS) State Key Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100080China

Atomistic detailed hydration structures of poly(vinyl methyl ether)(PVME) have been investigated by molecular dynamics simulations under 300 K at various concentrations. Both radial distribution functions and the distance distributions between donors and acceptors in hydrogen bonds show that the hydrogen bonds between the polymer and water are shorter by 0.005 nm than those between water molecules. The Quasi-hydrogen bonds take only 7.2% of the van der Waals interaction pairs. It was found the hydrogen bonds are not evenly distributed along the polymer chain,and there still exists a significant amount(10%) of ether oxygen atoms that are not hydrogen bonded to water at a concentration as low as 3.3%. This shows that in polymer solutions close contacts occur not only between polymer chains but also between chain segments within the polymer,which leads to inefficient contacts between ether oxygen atoms and water molecules. Variation of the quasi-hydrogen bonds with the concentration is similar to that of hydrogen bonds,but the ratio of the repeat units forming quasi-hydrogen bonds to those forming hydrogen bonds approaches 0.2. A transition was found in the demixing enthalpy at around 30% measured by dynamic testing differential scanning calorimetry(DTDSC) for aqueous solutions of a mono-dispersed low molecular weight PVME,which can be related to the transition of the fractions of hydrogen bonds and quasi-hydrogen bonds at ～27%. The transition of the fractions of hydrogen bonds and quasi-hydrogen bonds at ～27% can be used to explain the demixing enthalpy transition at 30% at a molecular scale. In addition,at the concentration of 86%,each ether oxygen atom bonded with water is assigned 1.56 water molecules on average,and 'free' water molecules emerge at the concentration of around 54%.

关键词： poly(vinyl methyl ether)(PVME) molecular dynamics computer simulation hydrogen bond quasi-hydrogen bond