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Modeling of drag reduction in turbulent channel flow with hydrophobic walls by FVM method and weakly-compressible flow equations

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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

盐爪爪根际土壤产IAA菌株分离及促生特性分析

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草业学报 2024年第4期33卷 110-121页

作者：程鑫宇王继莲麦日艳古·亚生李明源喀什大学生命与地理科学学院新疆喀什844006 新疆帕米尔高原生物资源与生态自治区重点实验室新疆喀什844006

为丰富具有产吲哚-3-乙酸(IAA)功能的植物根际促生菌(PGPR),开发高效微生物菌肥,从南疆克孜勒苏柯尔克孜自治州耐盐植物盐爪爪根际土壤中分离产IAA的菌株。结合16S rDNA的限制性片段长度多态性PCR技术(PCR-RFLP)与16S rDNA序列分析进行... 详细信息

为丰富具有产吲哚-3-乙酸(IAA)功能的植物根际促生菌(PGPR),开发高效微生物菌肥,从南疆克孜勒苏柯尔克孜自治州耐盐植物盐爪爪根际土壤中分离产IAA的菌株。结合16S rDNA的限制性片段长度多态性PCR技术(PCR-RFLP)与16S rDNA序列分析进行菌种鉴定,分析高产IAA菌株对玉米和小麦种子发芽的影响,并通过盆栽试验验证其对盐碱胁迫下植株幼苗生长(株高、茎粗、地上干重等)的影响。结果表明,共筛选到67株PGPR菌株,其分泌IAA能力为16.65~71.63 mg·L^(-1),尤以PM14、PM18分泌量较高。PM14和PM18菌株同时兼具解磷、固氮能力。所有菌株分属6个菌属,以肠杆菌属占绝对优势。接种PM14和PM18均促进了玉米和小麦种子萌发,但菌液浓度高低对种子发芽的影响有显著差异(P<0.05)。接种处理增加了玉米株高、鲜重、地上干重、茎粗和根干重,分别增加了4.7%~37.2%、28.8%~94.5%、15.8%~157.9%、4.4%~35.5%和23.5%~82.4%,但叶绿素含量无显著变化。接种处理增加了小麦株高、茎粗、鲜重和地上干重,分别增加了9.5%~33.1%、13.0%~49.6%、57.4%~112.8%和71.4%~114.3%。除接种灭活的PM14导致小麦根干重与对照相比无显著差异,其他处理均有积极作用,提高了52.8%~69.0%,而所有处理对叶绿素含量均无显著影响。综上,本研究筛选的产IAA菌株提高了植株在盐碱胁迫下的抗性,对开发适用于盐碱地区的微生物菌肥有重要意义。

关键词：吲哚-3-乙酸植物根际促生菌盐碱胁迫促生微生物菌肥

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

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盐碱地旱生芦苇根际解磷菌株筛选及促生特性

江苏农业学报 2024年第1期40卷 64-74页

作者：王继莲王冬玲周茜张甜李明源喀什大学生命与地理科学学院新疆喀什844006 新疆帕米尔高原生物资源与生态自治区重点实验室新疆喀什844006

为进一步挖掘解磷菌菌种资源,研制适合于盐碱地作物的促生菌剂,利用选择性培养基从新疆克孜勒苏柯尔克孜自治州盐碱地旱生芦苇(Phragmites australis)根际土壤中筛选解磷菌株。结合限制性片段长度多态性技术与16S rDNA测序进行菌株鉴定... 详细信息

为进一步挖掘解磷菌菌种资源,研制适合于盐碱地作物的促生菌剂,利用选择性培养基从新疆克孜勒苏柯尔克孜自治州盐碱地旱生芦苇(Phragmites australis)根际土壤中筛选解磷菌株。结合限制性片段长度多态性技术与16S rDNA测序进行菌株鉴定,并挑选解磷能力突出的优良菌株开展植物接种试验。本试验共筛选到47株解磷菌,其中32株可溶解无机磷,溶磷量为55.8~722.3 mg/L;37株可溶解有机磷,溶磷量为11.8~34.4 mg/L。47株解磷菌隶属于7个属,以肠杆菌属(Enterobacter)占绝对优势。解磷菌株有效促进了拟南芥植株的生长和根系发育,以芽孢杆菌Bacillus ***-2和类芽孢杆菌Paenibacillus ***-1的促生作用最显著。解磷菌株对盐碱土中小麦地上部分(株高、茎粗、地上部分鲜质量和地上部分干质量)和地下部分(根鲜质量、根干质量)也表现出积极影响,以Enterobacter ***-9和Enterobacter ***-2促生作用最突出。本研究筛选的解磷菌株具有一定的应用潜力,对开发适用于盐碱地的微生物肥料有重要意义。

关键词：解磷菌盐碱土壤促生作用微生物肥料

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奥氏体不锈钢换热管胀接残余应力分析

石油化工设备 2024年第5期53卷 38-42页

作者：李明远董中鹏康东明高慧北京应力分析科技有限公司北京102600 北京市热力工程设计有限责任公司北京100078

换热管与管板的可靠性连接是热交换器安全运行的重要保障。模拟了304不锈钢换热管与16Mn管板焊胀并用结构的内压加载过程,对比了胀接分别采用强度胀和贴胀的残余应力。研究表明,胀接内压小于30 MPa时,强度焊+强度胀结构与强度焊+贴胀结... 详细信息

换热管与管板的可靠性连接是热交换器安全运行的重要保障。模拟了304不锈钢换热管与16Mn管板焊胀并用结构的内压加载过程,对比了胀接分别采用强度胀和贴胀的残余应力。研究表明,胀接内压小于30 MPa时,强度焊+强度胀结构与强度焊+贴胀结构都处于弹性变形范围,内压卸载后无残余应力。胀接内压在30~40 MPa时,残余应力增加迅速,之后增速变缓。胀接内压在30~175 MPa时,2种结构残余应力相近。胀接内压大于175 MPa时,2种结构残余应力差异逐渐明显,开槽结构残余应力明显大于无槽结构。在胀接压力加载到100 MPa并卸压至0 MPa后,2种结构残余应力分布没有明显差异,开槽对残余应力基本没有影响。

关键词：换热管管板胀接应力有限元分析

产胞外多糖多功能促生菌的筛选鉴定及促生评价

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生物技术通报 2024年第3期40卷 273-285页

作者：常海霞李明源麦日艳古·亚生周茜王继莲喀什大学生命与地理科学学院喀什844000 新疆帕米尔高原生物资源与生态重点实验室喀什844000

【目的】探究产胞外多糖(exopolysaccharides,EPS)菌株在促进盐碱土中植物生长,改善土壤性能等方面的影响,为研制适用于盐碱土壤修复的微生物菌剂奠定基础。【方法】从新疆喀什地区盐碱草地根际土壤中筛选产胞外多糖菌株,基于16S rRNA... 详细信息

【目的】探究产胞外多糖(exopolysaccharides,EPS)菌株在促进盐碱土中植物生长,改善土壤性能等方面的影响,为研制适用于盐碱土壤修复的微生物菌剂奠定基础。【方法】从新疆喀什地区盐碱草地根际土壤中筛选产胞外多糖菌株,基于16S rRNA基因序列比对及系统发育分析对产胞外多糖菌株进行种属鉴定,采用单因素和响应面法优化最高产菌株的培养基组分,通过接种试验评估其对盐碱土栽培植物的促生效果及土壤团聚体的影响。【结果】共筛选出19株具有产胞外多糖能力的菌株,隶属于7个菌属,以假单胞菌属(Pseudomonas)占绝对优势。菌株产糖量介于236-1544 mg/L,尤以泛菌属Pantoea MQ A0产糖量最高,且兼具固氮、产吲哚乙酸(IAA)和铁载体、解磷等功能。MQ A0的最适产糖发酵培养基为甘油12.5 mL/L,蛋白胨9.0 g/L,酵母粉5.5 g/L,CaCO_(3)5.1 g/L,在此条件下菌株产糖量达2436 mg/L,较优化前增加57.8%。接种MQ A0发酵液使盐碱土栽培的玉米株高、鲜重、茎粗、须根数和总根长分别提高41.2%、203.0%、42.7%、30.4%和99.7%;粗多糖提取液对土壤团聚体的形成也有显著促进作用(P<0.05)。【结论】高产胞外多糖菌株MQ A0兼具多种促生特性,在促进盐碱土中植物生长和土壤改良方面效果显著。

关键词：产胞外多糖菌株盐碱草地响应面法盐碱土土壤团聚体

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