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航空动力学报 2013年第7期28卷 1526-1538页

作者： tian Xiao-pei SHAN Peng School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

Two strategies extended the single-cascade methods from a compressible three-dimensional inverse method for radial and mixed flow turbomachines to two three-dimensional multi-cascade co-design methods for single-stage centrifugal *** two three-dimensional methods and a typical quasi-threedimensional streamline curvature through-flow inverse method were employed to design the same subsonic high-speed single-stage centrifugal *** compressor performances were simulated by a commercial Reynolds averaged Navier-Stokes(RANS) equations *** studies show that two three-dimensional codesign methods are reasonable and *** was found that : firstly the blade camber angle designed by the three-dimensional methods was larger than that designed by the quasi-three-dimensional method;and secondly with regard to two three-dimensional methods with different boundary conditions,the co-design result differences between the diffusers were small,but those between the deswirlers were relatively large.

关键词： centrifugal compressor through-flow inverse method three-dimensional inverse problem streamline curvature approach Clebsch formulation multi-cascade co-design

Epichlo? festucae var. lolii endophyte affects host response to fungal disease progression in perennial ryegrass (Lolium perenne)

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Science China(Life Sciences) 2019年第9期62卷 1264-1265页

作者： pei tian Zhibiao Nan State Key Laboratory of Grassland Agro-ecosystems/ Key Laboratory of Grassland Livestock Industry Innovation Ministry of Agriculture and Rural Affairs/College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730020China

Dear Editor,Perennial ryegrass (Lolium perenne) is a globally important forage and turf grass species that commonly forms symbiotic associations with the asexual fungal endophyte—Epichloe festucae *** endophytes mutualistically interact with host plants by providing major fitness enhancements and protection from both biotic and abiotic stresses (Young et al.,2013).Previous studies have shown that Epichloe festucae *** inhibits the growth of plant pathogenic fungi and fungal spore germination in *** studies conducted in the lab or field confirmed that endophytes inhibited pathogen invasion and lesion development in perennial ***,endophytes are not always beneficial,and may even weaken the host plant and reduce the disease resistance of the *** inconsistent or contrasting results in Festuca spp.,Achnatherum inebrians and Leymus chinensis have also been reported (Wang et al.,2016).

关键词： disease resistance interact with Asexual endophyte

Preparation and Properties of Doped Lanthanum Gallate Film on a Ni/SDC Porous Anode Support

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Chemical Research in Chinese Universities 2006年第5期22卷 643-646页

作者： HE Qiang HE tian-min pei Li JI Yuan College of Physics Jilin University Changchun 130023 P. R. China

A 65. 8-μm dense doped lanthanum gallate La0.8Sr0.2 Ga0.85 Mg0.15 O2.825（LSGM）film was prepared on a porous Ni/SDC（samarium doped ceria, Ce0.8Sm0.2O1.9 ） anode support by colloid susponsion deposition with incomplete crystallization LSGM powder as a starting material. The phase composition and micromorphology of the LSGM film were characterized by X-ray diffraction and scanning electron microscopy. The electrical properties of the LSGM film and the performances of the LSGM film solid oxide fuel cell were also analyzed. The results show that beth the dense LSGM film on the porous anode support, and the required phase composition of the LSGM film were obtained simultaneously by sintering at 1400 ℃ for 6 h. The adhesion between the LSGM film and the porous anode support is very strong. The electrical conductivities of the LSGM film on the porous anode support are 0. 113 and 0. 173 S/cm at 800 and 850℃, respectively. The maximum output power density of the LSGM film cell is 177 mW/cm^2 at 700℃.

关键词： Doped lanthanum gallate Film Electrical property Solid oxide fuel cell Anode support

Potential roles of glucagon-like peptide-1-based therapies in treating non-alcoholic fatty liver disease

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World Journal of Gastroenterology 2014年第27期20卷 9090-9097页

作者： Ye Liu Rui Wei tian-pei Hong Department of Endocrinology and Metabolism Peking University Third Hospital

Glucagon-like peptide-1(GLP-1)-based therapies have demonstrated efficacy and safety in treating type 2 diabetes, which shares a similar pathophysiological mechanism with non-alcoholic fatty liver disease(NAFLD). Recent studies showed that glucose-induced GLP-1 secretion was decreased in patients with NAFLD and that the level of dipeptidyl peptidase-4, which inactivates intact GLP-1, was upregulated. Moreover, the expression of the GLP-1 receptor was downregulated in livers from patients with NAFLD, indicating an association of defective GLP-1 signalling with NAFLD. Notably, GLP-1-based therapies are reported to be effective in improving hepatic endpoints in patients with NAFLD, such as reducing hepatic fat content, hepatic steatosis and plasma transaminase levels, and preventing fibrosis. GLP-1-based therapies are beneficial for body weight control and glycaemic normalisation, which are important for the management of NAFLD. Moreover, clinical and preclinical studies showed that GLP-1-based agents might directly exert their actions on the liver through activation of functional GLP-1 receptors in *** possible mechanisms involve regulating gene expression that is associated with insulin resistance and lipid metabolism, and suppressing oxidative stress in the liver cells, thus preventing the development and progression of NAFLD. Based on these promising data, large-scale randomised controlled trials are warranted to assess the efficacy and safety of GLP-1-based therapies in treating NAFLD.

关键词： Non-alcoholic fatty liver disease Glucagon-like peptide-1 Dipeptidyl peptidase-4 Insulin resistance Oxidative stress Lipid metabolism

Influences of rock fragments on the hydraulics and erosion of concentrated runoff in steep spoil heaps on the Loess Plateau of China

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International Journal of Sediment Research 2022年第5期37卷 553-562页

作者： Wenzhao Guo Hongliang Kang Xiao Yu Wenlong Wang pei tian State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Water and Soil Conservation Northwest Agriculture & Forestry University Key Laboratory for Geographical Process Analysis & Simulation of Hubei Province Central China Normal University

The soil-rock mixed spoil heaps are prone to severe soil erosion during heavy rain, causing severe land degradation and ecological and environmental damage. Nevertheless, past research on the erosion on spoil heaps has focused on soil particles that were readily eroded and disregarded the rock fragments(RF) that were not readily eroded. To explore the effect of the RF embedded in spoil heaps on the hydraulics of and erosion caused by concentrated runoff, scour-erosion experiments were implemented on three types of spoil heaps: RF = 7%, RF = 45%, and RF = 69%. The RF clearly reduced runoff and erosion on steep spoil heaps. As the RF increased from 7% to 69%, the runoff intensity and runoff coefficient decreased by 72.9%-79.1% and 83.2%-84.1% respectively, and the sediment concentration, soil denudation rate, and total soil loss decreased by 36.0%-47.8%, 83.7%-87.1%, and 87.0%-92.3%, *** rills were generated during the experiments, and the RF distinctly influenced the rill characteristics. High contents of RF restrained rill retreating and undercutting, and promoted rill widening. With an increase in RF, the flow shear stress and stream power gradually decreased, and the Darcy-Weisbach roughness coefficient increased. These findings imply that the RF dissipated the flow energy and reduced soil detachment capacity and sediment transport capacity. Soil detachment is strongly related to the Darcy-Weisbach roughness coefficient, Reynolds number, and runoff intensity,which may be the preferred descriptors of soil detachment. The current findings indicate that embedded rock fragments could effectively reduce soil loss on steep spoil heaps.

关键词： Soil erosion Runoff Rock fragments (RF) Rills Chinese loess plateau

Evaluation of soil erosion vulnerability in Hubei Province of China using RUSLE model and combination weighting method

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Journal of Mountain Science 2024年第10期21卷 3318-3336页

作者： YANG Yanpan tian pei JIA Tinghui WANG Fei YANG Yang HUANG Jianwu Key Laboratory for Geographical Process Analysis&Simulation of Hubei Province Central China Normal UniversityWuhan 430079China College of Urban and Environmental Sciences Central China Normal UniversityWuhan 430079China Department of Civil and Environmental Engineering University of AlbertaEdmontonABT6G 1H9Canada

Soil erosion has been recognized as a critical environmental issue *** previous studies have primarily focused on watershed-scale soil erosion vulnerability from a natural factor perspective,there is a notable gap in understanding the intricate interplay between natural and socio-economic factors,especially in the context of spatial heterogeneity and nonlinear impacts of human-land *** address this,our study evaluates the soil erosion vulnerability at a provincial scale,taking Hubei Province as a case study to explore the combined effects of natural and socio-economic *** developed an evaluation index system based on 15 indicators of soil erosion vulnerability:exposure,sensitivity,and *** addition,the combination weighting method was applied to determine index weights,and the spatial interaction was analyzed using spatial autocorrelation,geographical temporally weighted regression and geographical *** results showed an overall decreasing soil erosion intensity in Hubei Province during 2000 and *** soil erosion vulnerability increased before 2000 and *** areas with high soil erosion vulnerability were mainly confined in the central and southern regions of Hubei Province(Xiantao,tianmen,Qianjiang and Ezhou)with obvious spatial aggregation that intensified over *** factors(habitat quality index)had negative impacts on soil erosion vulnerability,whereas socio-economic factors(population density)showed substantial spatial variability in their *** was a positive correlation between soil erosion vulnerability and erosion intensity,with the correlation coefficients ranging from-0.41 and *** increase of slope was found to enhance the positive correlation between soil erosion vulnerability and intensity.

关键词： Soil erosion vulnerability RUSLE model Combination weighting method Driving factors Spatial heterogeneity

Lie Symmetry and Conserved Quantity of Three-Order Lagrangian Equations for Non-conserved Mechanical System

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Communications in Theoretical Physics 2006年第2期45卷 350-352页

作者： MA Shan-Jun YANG Xue-Hui YAN Rong HUANG pei-tian College of Physics and Communication Electronics Jiangxi Normal University Nanchang 330027 China

Based on the infinitesimal and one parameter transformation, the problem of Lie symmetry of three-order Lagrangian equations has been studied. Under Lie transformation, the sufficient and necessary condition which kee... 详细信息

关键词： three-order Lagrangian equation Lie symmetry conserved quantity

Reliability tests and improvements for Sc-contacted n-type carbon nanotube transistors

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Nano Research 2013年第7期6卷 535-545页

作者： Shibo Liang Zhiyong Zhang tian pei Ruoming Li Yan Li Lianmao Peng Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing 10087 I China Key Laboratory for the Physics and Chemistry of Nanodevices and College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871 China

Scandium （Sc） contacted n-type carbon nanotube （CNT） field-effected transistors （FETs） with back and top-gate structure have been fabricated, and their stability in air were investigated. It was shown that oxygen and water molecules may affect both the nanotube channel and Scinanotube contacts, leading to deteriorated contact quality and device performance. These negative effects associated with the instability of n-type carbon nanotube FETs can be eliminated through passivating the CNT devices by a thin layer of atomic-layer-deposition grown A1203 insulator. After passivation, the n-type carbon nanotube FETs are shown to exhibit excellent atmosphere stability even after being tested and exposed to air for over 146 days, and then much smoother output characteristics and reduced gate voltage hysteresis from I to 0.1 V were demonstrated when compared with devices without passivation. Lasting power-on tests were also performed on the passivated CNT FETs under large gate stress and high drain current in air for at least 10 h, revealing null device degradation and sometimes even improved performance. These results promise that passivated CNT devices are reliable in air and may be used in practical applications.

关键词： stability carbon nanotube n-type field-effect transistor passivation, reliability

Inhibition of hepatic interleukin-18 production by rosiglitazone in a rat model of nonalcoholic fatty liver disease

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World Journal of Gastroenterology 2008年第47期14卷 7240-7246页

作者： Hai-Ning Wang Yan-Rong Wang Guo-Qiang Liu Zhe Liu pei-Xian Wu Xiao-Ling Wei tian-pei Hong Departmentof Endocrinology Peking University Third Hospital Beijing100191 China

AIM:To investigate the effects of rosiglitazone(RGZ) on expression of interleukin-18(IL-18) and caspase-1 in liver of non-alcoholic fatty liver disease(NAFLD) ***:Twenty-eight Sprague-Dawley(SD) rats were randomly divided into control,NAFLD,and RGZ treated NAFLD groups.A NAFLD rat model of NAFLD was established by feeding the animals with a high-fat diet for 12 *** NAFLD animals were treated with RGZ or vehicle for the last 4 wk(week 9-12) and then sacrificed to obtain liver *** changes were analyzed with HE,oil red O and Masson's trichrome *** of IL-18 and caspase-1 were detected using immunohistochemical staining and semi-quantitative reverse-transcription polymerase chain reaction(RT-PCR) ***:The expression levels of both IL-18 and caspase-1 were higher in the liver of NAFLD group than in the control ***,inflammation and fibrosis,found in the liver of NAFLD rats,were significantly improved 4 wk after RGZ *** elevated hepatic IL-18 and caspase-1 expressions in NAFLD group were also significantly attenuated after RGZ ***:RGZ treatment can ameliorate increased hepatic IL-18 production and histological changes in liver of NAFLD *** beneficial effects of RGZ on NAFLD may be partly due to its inhibitory effect on hepatic IL-18 production.

关键词： Insulin resistance Interleukin-18 Nonalcoholic fatty liver Rosiglitazone

Hot-pressed sintering of W/Cu functionally graded materials prepared from copper-coated tungsten powders

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Rare Metals 2020年第10期39卷 1229-1236页

作者： pei tian Yi Feng Meng Xia Lan Zhao Cheng-Yu Cai Ke Liu Xiao-Chen Huang School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Department of Material Engineering Zhejiang Industry and Trade Vocational CollegeWenzhou 325000China

The three-layered(W-60 vol%Cu/W-40 vol%Cu/W-20 vol%Cu)W/Cu functionally graded material(FGM)containing a Cu network structure was fabricated at different temperatures by hot-pressed sintering produced from copper-coated tungsten *** effects of various sintering temperatures on relative density,microstructure,thermal conductivity,hardness and flexural strength were *** electron microscopy(SEM)and X-ray diffraction(XRD)analysis show that a Cu network extends throughout the W/Cu FGM specimens sintered at 1065℃and the graded structure can be retained perfectly,and W particles are distributed *** low-temperature sintering densification of W/Cu FGM arises because the sintering mode of the copper-coated tungsten particles includes just sintering Cu to Cu,rather than Cu to W,Cu to Cu and W to W,as required for conventional powder *** relative density of W/Cu FGM sintered at 1065℃for 3 h under a load of25 MPa is 96.1%.The thermal conductivity is up to204 W·m^-1·K^-1 at normal temperature and 150 W·m^-1·K^-1at 800℃.And the Vickers hardness varies with the gradient of different layers from 3.34 to 4.05 GPa.

关键词： Copper-coated tungsten powders Hot-pressed sintering W/Cu functionally graded materials Microstructure Performance