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COMPUTATIONAL FLUID DYNAMICS(CFD) SIMULATIONS OF DRAG REDUCTION WITH PERIODIC MICRO-STRUCTURED WALL

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Chinese Journal of Mechanical Engineering 2008年第2期21卷 77-80页

作者： LI Gang ZHOU Ming WU Bo ye xia CAI Lan School of Automobile and Traffic Engineering Jiangsu University Zhenj ang 212013 Ch na School of Material Science and Engineering Jiangsu University Zhenjiang 212013 China

Computational fluid dynamics（CFD） simulations are adopted to investigate rectangular microchannel flows with various periodic micro-structured wall by introducing velocity slip boundary condition at low Reynolds number. The purpose of the current study is to numerically find out the effects of periodic micro-structured wall on the flow resistance in rectangular microchannel with the different spacings between microridges ranging from 15 to 60 pm. The simulative results indicate that pressure drop with different spacing between microridges increases linearly with flow velocity and decreases monotonically with slip velocity; Pressure drop reduction also increases with the spacing between microridges at the same condition of slip velocity and flow velocity. The results of numerical simulation are compared with theoretical predictions and experimental results in the literatures. It is found that there is qualitative agreement between them.

关键词： Reynoids numbers Slip velocity Drag reduction Computational fluid dynamics(CFD) simulations

Luminescent properties of a new Nd^(3+)-doped complex with two different carboxylic acids and pyridine derivative

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Rare Metals 2013年第5期32卷 490-495页

作者： Yun-xia ye Li-Hua Wei Wei-Chen Mei Chen Yin-Qun Hua School of Mechanical Engineering Jiangsu University Institute of Laser Technology Jiangsu University School of Material Engineering Jiangsu University

A new Nd3＋-doped organic complex featuring two different perfluorinated carboxylic acids as the first ligand and pyridine derivative 2-amino-3-chloro-5-（tri- fluoromethyl）pyridine as the second ligand was designed and synthesized. Successful coordination between the ligands and central rare earth ions was confirmed by Fourier transform infrared spectroscopy （FT-IR） spectra, 1H nuclear magnetic resonance （1H NMR） spectra, and UV spectra, and the synthesized complex is inferred to be eight-coordinate structure. Solution of the complex dis- solved in DMSO-d6 was prepared and then its fluorescence spectrum, UV-Vis-NIR absorption spectrum, and fluorescence decay curve were tested. The fluorescent lifetime is about 7 txs. Based on the above experimental research, Judd-Ofelt analysis was carried out, and the results indi- cate that appropriate coordination environment around Nd3＋ in this solution results in a high fluorescent quantum efficiency 2 % and a large stimulated emission cross-section about 3.2 × 10^-20 cm^2 at 1,064 nm.

关键词： Nd Organic solution Liquid laser Quantum efficiency Judd-Ofelt theory

On the measurement of slip length for liquid flow over super-hydrophobic surface

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Chinese Science Bulletin 2009年第24期54卷 4560-4565页

作者： LI Jian ZHOU Ming CAI Lan ye xia YUAN Run Center for Photon Manufacturing Science and Technology Jiangsu University Zhenjiang 212013 China

To design a surface with large slip or larger drag reduction is a pop issue in the fields of liquid transporting and body swimming. In this context, it is a crucial problem to measure the slip length for these surfaces. Here we propose a novel method by using rheometer for this objective. This method is implemented by designing the distribution of the super-hydrophobic area on the sample. Using this method, a slip length of 40 μm for 70 wt% glycerin flow over a super-hydrophobic surface with stripe structure (the period, width and height of ridges are 150 μm, 40 μm and 65 μm, respectively) is measured. The result shows that the slip length measured using this method is in good agreement with former results measured by other methods. This method is fit for measuring the slip length of super-hydrophobic surface whose structure ranges from microto nanoscale.

关键词：疏水表面长度测量流量测量滑移液体条纹结构纳米尺度微米

Testing complete plastomes and nuclear ribosomal DNA sequences for species identification in a taxonomically difficult bamboo genus Fargesia

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Plant Diversity 2023年第2期45卷 147-155页

作者： Shi-Yu Lv xia-Ying ye Zhong-Hu Li Peng-Fei Ma De-Zhu Li School of Life Science Northwest UniversityXi'anShaanxi710069China Germplasm Bank of Wild Species Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan650201China Agronomy and Life Science Department Zhaotong UniversityZhaotongYunnan657000China Kunming College of Life Science University of Chinese Academy of SciencesKunmingYunnan650201China

Fargesia,the largest genus within the temperate bamboo tribe Arundinarieae,has more than 90 species mainly distributed in the mountains of Southwest *** Fargesia bamboos are important components of the subalpine forest ecosystems that provide food and habitat for many endangered animals,including the giant ***,species-level identification of Fargesia is ***,the rapid radiation and slow molecular evolutionary rate of Fargesia pose a significant challenge to using DNA barcoding with standard plant barcodes(rbcL,matK,and ITS) in *** progress in the sequencing technologies,complete plastid genomes(plastomes) and nuclear ribosomal DNA(nrDNA)sequences have been proposed as organelle barcodes for species identification;however,these have not been tested in *** collected 196 individuals representing 62 species of Fargesia to comprehensively evaluate the discriminatory power of plastomes and nrDNA sequences compared to standard *** analysis indicates that complete plastomes have substantially higher discriminatory power(28.6%) than standard barcodes(5.7%),whereas nrDNA sequences show a moderate improvement(65.4%) compared to ITS(47.2%).We also found that nuclear markers performed better than plastid markers,and ITS alone had higher discriminatory power than complete *** study also demonstrated that plastomes and nrDNA sequences can contribute to intrageneric phylogenetic resolution in ***,neither of these sequences were able to discriminate all the sampled species,and therefore,more nuclear markers need to be identified.

关键词： Fargesia Genome-skimming DNA barcoding Plastome Ribosomal DNA

High temperature oxidation behavior of Ni-based superalloy GH586 in air

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Rare Metals 2017年第11期36卷 878-885页

作者： Jiang-Dong Cao Jun-Song Zhang Yin-Qun Hua Zhen Rong Rui-Fang Chen Yun-xia ye School of Material Science and Engineering Jiangsu UniversityZhenjiang 212013 China Mechanical and Electrical Department Nantong Shipping College Nantong 226010 China School of Mechanical Engineering Jiangsu UniversityZhenj iang 212013 China

In this paper, the isothermal oxidation kinetics and oxidation behavior of GH586 superalloy from 800 to 1000℃ were investigated. The oxide scale morphologies of the surfaces and the cross sections after oxidation were characterized by means of X-ray diffraction （XRD） and scanning electron microscope （SEM） equipped with energy-dispersive spectroscopy （EDS）. The results show that the growth of the oxide scales on the surface of superalloy GH586 obeys a parabolic law with the activa- tion energy of 241.4 ***1-1 from 800 to 1000℃ The dense oxide scale formed at 800℃ is mainly composed of Cr203, NiCr204 and a small amount of TiO2. At 900℃, the oxide scale is divided into two layers： the outer layer with multiple cracks is mainly composed of ＂Cr203 and TiO2, while the inner is a layer of dense Cr203. Under the oxide scale, aluminum-rich oxides along the grain bound- aries are generated by the internal oxidation. At 1000 ℃for 100 h, cracks throughout the whole oxide film accel- erate the oxidation rate of Ni-based superalloy GH586 and large blocks of TiO2 in the oxide scale are generated, resulting in the spallation of oxide scale.

关键词： Ni-based superalloy Internal oxidation Hightemperature oxidation behavior Oxidation kinetics

In-situ TEM Observation of Cementite Coarsening Behavior of 5Mn Steel during Tempering

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Journal of Iron and Steel Research International 2016年第5期23卷 442-446页

作者： ye xia Xi-nan LUO xiao-yan ZHONG Hui-hua ZHOU Cun-yu WANG Jie SHI National Center for Electron Microscopy in Beijing School of Materials Science and EngineeringKey Laboratory of Advanced Materials(MOE)The State Key Laboratory of New Ceramics and Fine ProcessingTsinghua UniversityBeijing 100084China Central Iron and Steel Research Institute Beijing 100081China

The cementite formation and coarsening behaviors of 0. 2 mass% C-5 mass% Mn steel during tempering at 500℃ were investigated by in-situ transmission electron microscope（ TEM）. In-situ TEM observation showed uniform distribution of cementite particles at the early stage of tempering in the rapidly heated（ 500 ℃ / s） sample. Elemental analysis confirmed that the cementite growth was dominated by Mn diffusion. During the cementite growth,the coarsening behavior of intragranular cementite was significantly controlled by the matrix diffusion,while that of the intergranular cementite was mainly governed by the boundary diffusion. The in-situ TEM observation revealed that the dislocation pipe diffusion of Mn took place during tempering,which accelerated the Mn diffusion between cementite particles. The coarsening rates of individual cementite particles were calculated based on the in-situ TEM observation.

关键词： in-situ observation cementite coarsening behavior Mn diffusion 5Mn steel tempering

Overexpression and Immunosuppressive Functions of Transforming Growth Factor 1,Vascular Endothelial Growth Factor and Interleukin-10 in Epithelial Ovarian Cancer

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Chinese Journal of Cancer Research 2012年第2期24卷 130-137页

作者： Chan-zhen Liu Li Zhang xiao-hong Chang ye-xia Cheng Hong-yan Cheng Xue ye Tian-yun Fu Jun Chen Heng Cui Gynecology Oncology Center Peking University People's HospitalBeijing 100044China

Objective： Transforming growth factor-1 （TGF-βI）, vascular endothelial growth factor （VEGF）, and interleukin-lO （IL-10） may be critical cytokines in the microenvironment of a tumor, playing roles in immune suppression. This study was conducted to elucidate the roles and immunosuppressive functions of these cytokines in epithelial ovarian cancer （EOC）. Methods： The expression levels of TGF-β1, VEGF and IL-10 in malignant tissue were evaluated by immune- histochemistry and compared with corresponding borderline, benign, and tumor-free tissues. Moreover, relationships among the levels of these cytokines and correlations between expression and the prognosis of EOC were analyzed by Pearson rank correlations and multi-factor Logistic regression. The roles of TGF-βI, VEGF, and IL-lO in the immunosuppressive microenvironment of ovarian cancer were studied through dendritic cell （DC） maturation and CD4＋CD25＋FoxP3＋ Treg generation in vitro experiments. Results： TGF-β1, VEGF, and IL-IO were expressed TGF-β1 was an independent prognostic factor for EOC n 100%, 74.69%, and 54.96% of EOC patients, respectively. L-IO was significantly co-expressed with VEGF. In vitro, VEGF and TGF-β31 strongly interfered with DC maturation and consequently led to immature DCs, which secreted high levels of IL-IO that accumulated around the tumor site. TGF-β1 and IL-10 induced Treg generation without antigen presentation in DCs. Conclusions： TGF-βI, VEGF and IL-IO play important roles in EOC and can lead to frequent immune evasion events.

关键词： Epithelial ovarian cancer Tumor microenvironment Immunosuppression Cytokines

Microstructure evolution of loess under multiple collapsibility based on nuclear magnetic resonance and scanning electron microscopy

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Journal of Mountain Science 2021年第10期18卷 2612-2625页

作者： WANG Hai-man NI Wan-kui YUAN Kang-ze LI Lan NIE Yong-peng GUO ye-xia College of Geological Engineering and Geomatics Chang’an UniversityXi'an 710054China Key Laboratory of Western China's Mineral Resources and Geological Engineering Ministry of EducationChang’an UniversityXi'an 710054China

In recent years, the acceleration of urbanization in loess areas has prompted frequent dismantling and reconstruction of old urban areas. Demolition and reconstruction of buildings involve multiple collapses of the foundation. To study microstructure evolution of loess under multiple collapsibility, this paper selects undisturbed loess samples from Guyuan, Northwest China for multiple compression tests. Using nuclear magnetic resonance(NMR) imaging and scanning electron microscopy(SEM) as auxiliary methods, a combination of qualitative and quantitative analyses was used to study the microstructure of loess samples before and after various number of collapses under different pressures. Results show that the loess does undergo multiple collapse under 200 kPa pressure. Pore is an important reason for loess collapse. The initial collapse comes primarily from the compression of macropores and mesopores, and the second collapse comes primarily from mesopore compression. The compression process of loess can be roughly divided into two stages. First, under the action of dissolution and compression, the relative displacement of soil particles occurs. Macropores and mesopores are destroyed first, generating small pores. Second, with increasing pressure and times of collapses, pore compression gradually transforms into small pore compression. During the first collapse, particle aggregates disintegrate due to water and pressure. However, with increasing times of collapses, the contact relationship between particles gradually changes from the point contact to face contact. Loess particles tend to gradually become rounded. The study of the microstructure provides the possibility to further reveal the mechanism of multiple collapsibility of loess.

关键词： Loess Multiple collapse Microstructure Nuclear magnetic resonance Pore volume

A New Sesquiterpene Lactones Glucoside from Notoseris psilolepis

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Chinese Chemical Letters 2000年第11期11卷 1007-1008页

作者： xiao xia ye Ji Shuang CHEN Ming Kui WANG Ke Xin HUANG Li Sheng DING Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041 Department of Chemistry Wenzhou Medical CollegeWenzhou 325003 College of Life Science Zhejiang UniversityHangzhou 310005

A new sesquiterpene lactone glucoside, notoserolide C (1), was isolated from the whole plant of Notoseris psilolepis Shih. By means of spectral analysis including MS, NMR (H-1 NMR, C-13 NMR, H-1-H-1 COSY, HMQC, HMBC) ... 详细信息

关键词： Notoseris psilolepis asteraceae notoseolide C