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Acta Mechanica Sinica 2011年第2期27卷 200-207页

作者： ling li ming-Shun yuan State Key Laboratory of Hydroscience and Engineering Tsinghua University 100084 Beijing China

In this paper the effects of hydrophobic wall on skin-friction drag in the channel flow are investigated through large eddy simulation on the basis of weaklycompressible flow equations with the MacCormack’s scheme on collocated mesh in the FVM framework. The slip length model is adopted to describe the behavior of the slip velocities in the streamwise and spanwise directions at the interface between the hydrophobic wall and turbulent channel flow. Simulation results are presented by analyzing flow behaviors over hydrophobic wall with the Smagorinky subgrid-scale model and a dynamic model on computational meshes of different resolutions. Comparison and analysis are made on the distributions of timeaveraged velocity, velocity fluctuations, Reynolds stress as well as the skin-friction drag. Excellent agreement between the present study and previous results demonstrates the accuracy of the simple classical second-order scheme in representing turbulent vertox near hydrophobic wall. In addition, the relation of drag reduction efficiency versus time-averaged slip velocity is established. It is also foundthat the decrease of velocity gradient in the close wall region is responsible for the drag reduction. Considering its advantages of high calculation precision and efficiency, the present method has good prospect in its application to practical projects.

关键词： Wall turbulences · Large eddy simulation · Drag reduction · Hydrophobic wall · Weakly compressible flow

Colorimetric enantiodiscrimination of mandelic acid by indicator displacement assay

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Chinese Chemical Letters 2015年第8期26卷 1019-1021页

作者： Xue-Xian Chen li-ming yuan School of Energy and Environment Yunnan Normal University

The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu（II） is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu（II）. The △A could be increased to 0.12 by changing the ratio of（＋）- and（-）-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus △A relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.

关键词： proline indicator reserved resultant calibration excess violet guest isotherm tuned

Experimental study on asphaltene precipitation induced by CO_2 flooding

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Petroleum Science 2014年第1期11卷 174-180页

作者： DONG Zhao-xia WANG Jun liU Gang liN Mei-qin li ming-yuan Enhanced Oil Recovery Research Institute China University of Petroleum Beijing Key Laboratory for Greenhouse Gas Storage and Enhanced Oil Recovery Key Laboratory of Enhanced Oil Recovery CNPC

The effects of CO2 pressure,temperature and concentration on asphaltene precipitation induced by CO2 were studied using a high-pressure vessel,interfacial tensiometer,Fourier transform infrared （FTIR） and drill core displacement experimental *** results indicated that the content of asphaltene in crude oil decreased,and the interfacial tension between a model oil and distilled water increased,with an increase of CO2 pressure,decrease of temperature and increase of molar ratio of CO2 to crude oil when CO2 contacted crude oil in the high pressure *** content of asphaltene in sweepout oil and the permeability of test cores both also decreased with an increase of CO2 flooding *** main reason for changes in content of asphaltene in crude oil,in interfacial tension between model oil and distilled water and in the permeability of the test core is the precipitation of asphaltene which is an interfacially active substance in crude *** of asphaltene also blocks pores in the drill core which decreases the permeability.

关键词： CO2 flooding asphaltene precipitation oil-water interfacial tension core permeability

Glucose,cellobiose,lactose and raffinose used as chiral stationary phases in HPLC

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Chinese Chemical Letters 2008年第10期19卷 1248-1251页

作者： Jian Yu Wang Feng Zhao Mei Zhang Ya Peng li ming yuan Department of Chemistry Yunnan Normal University Kunming 650092 China

This paper presents the enantioseparation using glucose, cellobiose, lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC. Surprisingly, they also possess high enantioseparation selectivity, may be used in normal-phase and reversed- phase mode, and there is a big chiral discriminating complementary. This work indicates that oligosaccharides could soon become very attractive as a new class of chiral stationary phase for HPLC.

关键词： Oligosaccharides Chiral stationary phase HPLC

High-speed countercurrent chromatography for purification of single-walled carbon nanotubes

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Chinese Chemical Letters 2008年第11期19卷 1345-1348页

作者： Ying Cai Zhi Hong Yan Ying Chun Lv Min Zi li ming yuan Department of Chemistry Yunnan Normal University Kunming 650092 China Key Laboratory of Ministry of Education Jiangxi University of Chinese Traditional Medicine Nanchang 330004 China

A new chromatographic purification of single-walled carbon nanotubes using high-speed countercurrent chromatography is reported. The purification was accomplished on the basis of experiment that dispersed the single-walled carbon nanotubes with sodium dodecyl sulfate, and the result mixture was separated using the two phase system composed of n-butanol/water = 1/1 （v/v）. The sizes of SWNTs separated were observed by scanning electron microscopy. The results demonstrated that the high-speed countercurrent chromatography possessed a good efficency for purification of single-walled carbon nanotubes.

关键词： High-speed countercurrent chromatography Purification Sodium dodecyl sulfate Single-walled carbon nanotubes

Influence of dissolved oxygen content on oxidative stability of linked polymer solution

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Petroleum Science 2009年第4期6卷 421-425页

作者： Zhao-xia Dong Mei-qin lin Jian Xin ming-yuan li China Univ Petr Enhanced Oil Recovery Res Ctr Beijing 102249 Peoples R China

The influence of dissolved oxygen content on the oxidative stability of a linked polymer solution (LPS) was studied by micro-filtration, dynamic light scattering and viscosity measurements. The results showed that at the same temperature, the degree of the oxidative degradation of the LPS increased and the rapidity of the oxidative degradation was accelerated with the increase of the dissolved oxygen content. Consequently, the size of linked polymer coils (LPCs) of the LPS became small, and the plugging capability of the LPS decreased. At a fixed content of dissolved oxygen, with increasing degradation temperature, almost the same results were observed, namely, an increased degree of oxidative degradation, accelerated rapidity of the oxidative degradation and decreased plugging capacity, with decreased oxidative stability of LPS. At 90 °C, in the presence of oxygen, LPS lost its plugging capability after having been degraded for a period of time. But at 40 °C, LPS with low dissolved oxygen content could be stable for a long time. The decreased plugging ability of LPS after oxidative degradation is mainly caused by the decreased size and number of the LPCs due to the breaking of hydrolyzed polyacrylamide (HPAM) molecule segments and the structural changing of HPAM molecules.

关键词： linked polymer solution HPAM content of dissolved oxygen degradation stability

Design of scale model of plate-shaped absorber in a wide frequency range

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Chinese Physics B 2018年第4期27卷 299-304页

作者： li-ming yuan Yong-Gang Xu Wei Gao Fei Dai Qi-lin Wu Science and Technology on Electromagnetic Scattering Laboratory Shanghai 200438 China Key Laboratory of High Performance Fibers & Products Ministry of Education Donghua University Shanghai 201620 China

In order to design the scale model in a wide frequency range,a method based on the reflective loss is proposed according to the high-frequency approximation algorithm,and an example of designing the scale model of a plate-shaped absorber is given in this *** the example,the frequency of the full-size measurement ranges from 2.0 GHz to 2.4 GHz,the thickness of the full-size absorber is 1 mm and the scale ratio is 1/5.A two-layer scale absorber is obtained by the proposed *** thickness values of the bottom and top layer are 0.4 mm and 0.5 mm,***,the scattering properties of a plate model and an SliCY model are studied by FEKO to verify the effectiveness of the designed scale *** with the corresponding values from the theoretical scale model,the average values of the absolute deviations in 10 GHz～12 GHz are 0.53 d Bm^2,0.65 d Bm^2,0.76 d Bm^2 for the plate model and 0.20 d Bm^2,0.95 d Bm^2,0.77 d Bm^2 for the SliCY model while the incident angles are 0°,30°,and 60°,*** deviations fall within the Radar cross section（RCS） measurement ***,the work in this paper has important theoretical and practical significance.

关键词： scale model plate-shaped absorber wide frequency range RCS

Analysis of Genetic Diversity of Processing Apple Varieties

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Agricultural Sciences in China 2006年第10期5卷 745-750页

作者： SONG Ye ZHAI Heng YAO Yu-xin li ming DU yuan-peng College of Horticultural Science and Engineering Shandong Agricultural University Taian 271018 P.R.China

Genetic diversity of 18 processing apple varieties and two fresh varieties were evaluated using 12 simple sequence repeats （SSR） primer pairs previously identified in Malus domestica Borkh. A total of 87 alleles in 10 loci were detected using 10 polymorphic SSR markers selected within the range of 5-14 alleles per locus. All the 20 varieties could be distinguished using two primer pairs and they were divided into four groups using cluster analysis. The genetic similarity （GS） of groups analyzed using cluster analysis varied from 0.14 to 0.83. High acid variety Avrolles separated from other varieties with GS less than 0.42. The second group contained Longfeng and Dolgo from Northeast of China, the inherited genes of Chinese crab apple. The five cider varieties with high tannin contents, namely, Dabinette, Frequin rouge, Kermerrien, ***, and *** were clustered into the third group. The fourth group was mainly composed of 12 juice and fresh varieties. Principal coordinate analysis （PCO） also divided all the varieties into four groups. Juice and fresh apple varieties, Longfeng and Dolgo were clustered together, respectively, using both the analyses. Both the analyses showed there was much difference between cider and juice varieties, cider and fresh varieties, as well as Chinese crab apple and western European crab apple, whereas juice varieties and fresh varieties had a similar genetic background. The genetic diversity and differentiation could be sufficiently reflected by combining the two analytical methods.

关键词： processing apple varieties genetic diversity simple sequence repeats cluster analysis principal coordinate analysis

Enantioseparation of Aminoglutethimide by High-speed Countercurrent Chromatography Using Carboxymethly-β-cyclodextrin as Chiral Selector

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Chinese Chemical Letters 2006年第6期17卷 787-790页

作者： Ping AI Jia Chuan liU Min ZI Zhi Hua DENG Zhi Hong YAN li ming yuan Department of Chemistry Yunnan Normal University Kunming 650092

Enantioseparation of aminoglutethimide was performed by high-speed counter-current chromatography with a two-phase system composed of ethyl acetate： methanol： water = 10： 1： 9. The lower phase contained 20 mmol/L of carboxymethly-β-cyclodextrin as chiral selector. The enantiomers were separated in 1.2 h and identified by chiral HPLC. This method was very efficient for the chiral preparative separation.

关键词： High speed countercurrent chromatography enantioseparation aminoglutethimide,carboxymethly-β-cyclodextrin.

Intangible Cultural Heritage Goes Digital “Experience the Heritage: Digital Exhibition on China’s Intangible Cultural Heritage” held in Capital Museum

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China & The World Cultural Exchange 2010年第9期76卷 4-7页

作者： li ming Xin yuan

“Experience the Heritage： Digital Exhibition on China＇s Intangible Cultural Heritage” was recentlyheld in the Capital Museum in Beijing, as part of the celebrations to mark the 6fth annual Cultural Heritage Day.

关键词：非物质文化遗产首都博物馆数字化中国文物庆祝活动