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Symmetry-based description of laminar-turbulent transition

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Science China(Physics,Mechanics & Astronomy) 2019年第9期62卷 79-85页

作者： meng-juan xiao Zhen-Su She Department of Mechanics and Engineering Science and State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking University

We report a simple but accurate description of flat plate transitional flow based on a structural ensemble dynamics(SED) theory of wall turbulence. It is postulated and verified by simulation data that a multi-layer stress length(SL) function ?12 presents a two-state structure in the streamwise x direction, characterizing the laminar-turbulent transition. The resulting algebraic model(called SED-SL) predicts correctly for the first time the entire streamwise profiles of the friction coefficient, Cf(x), of all seven sets of experimental(of e.g. T3 series) and simulations data of flat plate transitional flows, with varying incoming turbulence intensities Tu(or scales), superior to other closure models, with a two-state correlation for transition location Rex*= 3.3 × 10^6(1 +(Tu/0.65)^4)^-1.5/4. The extension to accurate description of transitional flows of engineering interests is discussed.

关键词： SED theory stress length multi-layer

Smart Cellulose‑Based Janus Fabrics with Switchable Liquid Transportation for Personal Moisture and Thermal Management

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Nano-Micro Letters 2025年第1期17卷 333-347页

作者： Jianfeng Xi Yanling Lou Liucheng meng Chao Deng Youlu Chu Zhaoyang Xu Huining xiao Weibing Wu Jiangsu Co‑Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsJiangsu Provincial Key Lab of Sustainable Pulp and Paper Technology and Biomass MaterialsNanjing Forestry UniversityNanjing 210037People’s Republic of China College of Materials Science and Engineering Nanjing Forestry UniversityNanjing 210037People’s Republic of China Department of Chemical Engineering University of New BrunswickFrederictonNB E3B 5A3Canada Macromolecular Chemistry and Bavarian Polymer Institute University of BayreuthBayreuth 95440Germany

The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human ***,the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a ***,a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/*** cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport ***,hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability *** fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side,and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40℃.This smart fabric can quickly dissipate heat at high temperatures,while at low temperatures,it can slow down the heat dissipation rate and prevent the human from becoming too *** addition,the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic *** smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations.

关键词： Directional water transport Cotton fabric Anti-gravity directional liquid transportation Janus wettability

非布司他与别嘌呤醇治疗原发性痛风的疗效及其对胰岛素抵抗的影响研究

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中国全科医学 2017年第30期20卷 3745-3748页

作者：孟娟袁晓旭路跃武首都医科大学附属北京朝阳医院风湿免疫科北京市100020

目的比较非布司他与别嘌呤醇治疗原发性痛风的疗效及其对胰岛素抵抗(IR)的影响。方法选取2013年11月—2015年5月首都医科大学附属北京朝阳医院门诊收治的符合纳入标准的原发性痛风患者52例为研究对象。使用SPSS 19.0软件将患者按1∶1的... 详细信息

目的比较非布司他与别嘌呤醇治疗原发性痛风的疗效及其对胰岛素抵抗(IR)的影响。方法选取2013年11月—2015年5月首都医科大学附属北京朝阳医院门诊收治的符合纳入标准的原发性痛风患者52例为研究对象。使用SPSS 19.0软件将患者按1∶1的比例随机分为非布司他组(给予非布司他片)及别嘌呤醇组(给予别嘌呤醇片)。收集患者一般资料,分别检测患者治疗前和治疗24周末血清尿酸(UA)、天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)、肌酐(Cr)、空腹血糖(FBG)、空腹胰岛素(INS)水平,计算稳态模型评估胰岛素抵抗指数(HOMA-IR)。结果治疗前两组UA、AST、ALT、Cr、FBG、INS水平和HOMA-IR比较,差异无统计学意义(P>0.05);治疗后非布司他组UA、INS水平低于别嘌呤醇组(P0.05)。别嘌呤醇组治疗后UA水平低于治疗前(P<0.05);非布司他组治疗后UA、INS水平和HOMA-IR低于治疗前(P<0.05)。结论非布司他比别嘌呤醇能更有效地控制原发性痛风患者血清UA水平,并能改善IR情况。

关键词：痛风疗效比较研究别嘌呤醇胰岛素抵抗非布司他

Innovative dual-mode device integrating capacitive desalination and solar vapor generation for high-efficiency seawater desalination

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Journal of Energy Chemistry 2025年第1期100卷 171-179页

作者： Jiacheng Wang Zhaoyu Chen Ruduan Yuan Jiaxin Luo Ben Zhang Keju Ji meng Li juanxiu xiao Kuan Sun National Innovation Center for Industry-Education Integration of Energy Storage Technology MOE Key Laboratory of Low-grade Energy Utilization Technologies and SystemsCollege of Energy & Power Engineering Chongqing University Xuefeng Mountain Energy Equipment Safety National Observation and Research Station CQU-NUS Renewable Energy Materials & Devices Joint Laboratory Chongqing University Southwest Technology and Engineering Research Institute Jiangsu Provincial Key Laboratory of Bionic Functional Materials College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics State Key Laboratory of Marine Resources Utilization in South China Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University

Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater ***,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires *** this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive *** utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m-2h-1for condensate water yield under one-sun ***,the device exhibited a salt adsorption capacity of up to48 mg g-1and a salt adsorption rate of 2.1 mg *** addition,the salt adsorption capacity increased by approximately 32% under one-sun ***,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical *** calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive ***,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid *** work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.

关键词： Desalination

De novo synthesis of atropisomeric benzofurans via Cu/SPDO complex catalyzed asymmetric formal [3 + 2] annulation

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Science China Chemistry 2025年第1期68卷 174-180页

作者： Fan-xiao meng Xing-Yu Wang Ka Lu Ju-Song Yang Fu-Min Zhang Ai-Jun Ma Bao Du Yong-Qiang Tu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University School of Chemistry and Chemical Engineering Shanghai Jiao Tong University School of Biotechnology and Health Sciences Wuyi University

Herein, the de novo synthesis of atropisomeric benzofurans through the Cu/spirocyclic-pyrrolidine-oxazoline(SPDO) complex catalyze asymmetric formal [3 + 2] cycloaddition between quinones and ynamides is explored, producing a range of structurally diverse axially chiral benzofurans in satisfactory yields with good to excellent enantioselectivities. Furthermore, density functional theory calculations were applied to explain the possible reaction mechanism.

关键词： benzofuran atropisomers novel de novo synthetic strategy asymmetric formal [3 + 2] cycladdition Cu/SPDO complex DFT calculations

无底圆筒结构内填土压力分布和抗倾有效比计算

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天津大学学报（自然科学与工程技术版） 2004年第12期37卷 1035-1040页

作者：刘建起王海艳孟晓娟天津大学建筑工程学院天津300072

由于无底圆筒结构与有底结构相比,在结构沉降、基底应力等方面存在差异,导致二者的内填土压力分布明显不同,因此,传统的贮仓压力理论不能正确确定无底圆筒结构的筒内填土压力.采用模型试验,量测作用在无底圆筒结构上的土压力,分析无底... 详细信息

由于无底圆筒结构与有底结构相比,在结构沉降、基底应力等方面存在差异,导致二者的内填土压力分布明显不同,因此,传统的贮仓压力理论不能正确确定无底圆筒结构的筒内填土压力.采用模型试验,量测作用在无底圆筒结构上的土压力,分析无底圆筒结构与内填土和地基的相互作用,探讨圆筒结构在倾覆过程中内填土与筒壁间摩阻力调整机理.通过试验研究和理论分析得到,在对称荷载作用下筒内土压力分布分为三个区域,在非对称荷载作用下,由于筒内产生附加力矩而使土压力分布变为两个区域,且抗倾有效比约为对称荷载状况下的1.10倍.在此基础上,提出了对称荷载和非对称荷载(作用有侧向荷载)情况下,筒内填土压力和抗倾有效比的计算方法,前者适用于圆筒施工期的计算,后者适用于使用期的计算.

关键词：无底圆筒结构简内填土压力抗倾有效比调整机理附加力矩

miRNA-21-5p is an important contributor to the promotion of injured peripheral nerve regeneration using hypoxia-pretreated bone marrow-derived neural crest cells

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Neural Regeneration Research 2025年第1期20卷 277-290页

作者： meng Cong Jing-Jing Hu Yan Yu xiao-Li Li xiao-Ting Sun Li-Ting Wang Xia Wu Ling-Jie Zhu xiao-Jia Yang Qian-Ru He Fei Ding Hai-Yan Shi School of Medicine Nantong UniversityNantongJiangsu ProvinceChina Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Coinnovation Center of Neuroregeneration Nantong UniversityNantongJiangsu ProvinceChina Department of Physiology Jiangsu Health Vocational CollegeNanjingJiangsu ProvinceChina Department of Pathology Affiliated Hospital of Nantong UniversityNantongJiangsu ProvinceChina Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair Affiliated Hospital of Nantong UniversityNantongJiangsu ProvinceChina

Our previous study found that rat bone marrow–derived neural crest cells(acting as Schwann cell progenitors)have the potential to promote long-distance nerve ***-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular ***,the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain *** investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves,we collected conditioned culture medium from hypoxia-pretreated neural crest cells,and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose *** mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest *** performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest ***,to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons,we used a microfluidic axonal dissociation model of sensory neurons in vitro,and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons,which was greatly dependent on loaded ***,we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb,as well as muscle tissue morphology of the hind limbs,were obviously *** findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in ***-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell *** helps to explain the mechanism of action of the secretome and e

关键词： axotomy cell-free therapy conditioned medium extracellular vesicles hypoxic preconditioning microRNA oxygen-glucose deprivation peripheral nerve injury Schwann cell precursors

Ti6Al4V合金微弧氧化陶瓷膜的组织结构研究

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航空材料学报 2009年第2期29卷 39-42页

作者：蒙晓涓李卫京崔世海韩建民北京交通大学机械电子与控制工程学院北京100044 天津科技大学机械工程学院天津300222

采用微弧氧化技术在钛合金表面成功制备出膜厚约100μm的致密陶瓷膜以提高钛合金的耐磨性。SEM结果表明,陶瓷膜完整连续,与基体呈犬牙状牢固结合。XRD衍射结果表明:陶瓷膜主要由金红石型二氧化钛和A l2TiO5晶体相组成。显微硬度结果表... 详细信息

采用微弧氧化技术在钛合金表面成功制备出膜厚约100μm的致密陶瓷膜以提高钛合金的耐磨性。SEM结果表明,陶瓷膜完整连续,与基体呈犬牙状牢固结合。XRD衍射结果表明:陶瓷膜主要由金红石型二氧化钛和A l2TiO5晶体相组成。显微硬度结果表明钛合金微弧氧化陶瓷膜的显微硬度为862HV而基体合金硬度仅为412HV,陶瓷膜的硬度远远高于基体合金的显微硬度。摩擦磨损试验表明,镀膜的钛合金磨损量远小于不镀膜钛合金的磨损量,陶瓷膜能提高基体的摩擦磨损性能。

关键词：钛合金微弧氧化陶瓷膜耐磨性

Surface Modification of PVA Membranes by APTEOS for Pervaporation of Ethanol/Water Mixtures（摘要）

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华东理工大学学报（自然科学版） 2011年第1期37卷 44-44页

作者： meng xiao-juan ZHANG Qiu-gen LIU Qing-lin Department of Chemical ＆ Biochemical Engineering College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 Fujian China