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31篇 您的检索式:作者名="Pingli Liu"
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1The modified temperature term on Johnson-Cook constitutive model of AZ31 magnesium alloy with {0002} texture显示文摘The dynamic compression experiments with Split-Hopkinson Pressure Bar(SHPB)were performed on AZ31 magnesium alloy rolled sheet specimens in the normal direction(AZ31-ND)with{0002}texture at the temperature of 293-523 K and the strain rate of 0.001-2200 s^−1.The temperature term in Johnson-Cook(JC)constitutive model had been reasonably modified.This advantage made constitutive model promising for decribing the dynamic deformation behavior of AZ31-ND with{0002}texture more accurately.The obtained true stress-true plastic strain curves agreed well with the measured results in a wide range of strain rates and temperatures.The thermal softeninging,strain and strain rate hardening effect on the AZ31-ND with{0002}texture were discussed.The adiabatic shear band(ASB)of AZ31-ND with{0002}texture hat shaped specimen was successfully predicted by combining modified JC constitutive model and numerical simulation,which was also validated by Electron Back-Scattered Diffraction(EBSD)map under the same boundary condition.Feng Zhang Zheng Liu Yue Wang Pingli Mao Xinwen Kuang Zhenglai Zhang Yingdong Ju Xiaozhong Xu 2020Journal of Magnesium and Alloys2020,8,1:8
2Climate change and its effect on reference crop evapotranspiration in central and western Inner Mongolia during 1961-2009显示文摘水资源是到在中央、西方的内部蒙古的农业生产的主要限制之一,在的地方由干旱、半干旱的气候是特征的。参考庄稼土壤水分蒸发蒸腾损失总量(et 0 ) 是在农业生态系统的水周期的重要部分,它在庄稼生长和产量上有直接效果。et 0 上的气候变化的含意具有为关于安排的水管理和灌溉的农业的高重要性。这研究的目的是在时期上在在中央、西方的内部蒙古的 et 0 上在气候和它的效果分析变化 1961 ~ 2009。为这个目的,在越过学习区域的十个气象学的车站的数据被收集, FAO Penman-Monteith 56 方法被使用。结果证明平均温度,最大的温度和最小的温度由 0.49 莬增加了吗??Di HE Yaling LIU Zhihua PAN Pingli AN Liwei WANG Zhiqiang DONG Jingting ZHANG Xuebiao PAN Peiyi ZHAO 2013Frontiers of Earth Science2013,7,4:8
3Resveratrol compares with melatonin in improving in vitro porcine oocyte maturation under heat stress显示文摘Background: Resveratrol, an important phyto-antioxidant commonly found in grapes, mulberry, and other plants,has a variety of functions including anti-aging, anti-cancer and anti-inflammatory activities. In the current study, we investigated the beneficial effects of resveratrol on in vitro porcine oocyte maturation under heat stress(HS). The effect of resveratrol, melatonin and their combination on alleviating HS was compared according to the maturation rate of oocytes and the development competence of embryos after parthenogenetic activation(PA).Results: Supplementation with resveratrol(2.0 μmol/L) not only improved the nuclear maturation but also raised the blastocyst rate of porcine embryos' PA from oocytes that underwent HS by increasing their glutathione(GSH)level, reducing reactive oxygen species(ROS) and up-regulating the expression of Sirtuin 1(SIRT1). It was also found that melatonin(10^(-7)mol/L) and the combination of resveratrol(2.0 μmol/L) plus melatonin(10^(-7)mol/L) exhibited more potent effects than resveratrol alone regarding their protective activities on oocyte maturation under HS.Conclusions: This study compared the efficiencies of resveratrol, melatonin and their combination for protecting porcine oocytes from heat stress. The mechanisms are attributed to the fact that each treatment may have different ability to regulate the synthesis of steroid hormones and the expression of mature related genes.Yu Li Jing Wang Zhenzhen Zhang Jinyun Yi Changjiu He Feng Wang Xiuzhi Tian Minghui Yang Yukun Song Pingli He Guoshi Liu 2017Journal of Animal Science and Biotechnology2017,8,1:7
4First-principles calculations of structural,elastic and electronic properties of AB_(2)type intermetallics in Mg–Zn–Ca–Cu alloy显示文摘Electronic structure and elastic properties of MgCu_(2),Mg_(2)Ca and MgZn_(2)phases were investigated by means of first-principles calculations from CASTEP program based on density functional theory(DFT).The calculated lattice parameters were in good agreement with the experimental and literature values.The calculated heats of formation and cohesive energies shown that MgCu_(2)has the strongest alloying ability and structural stability.The elastic constants of MgCu_(2),Mg_(2)Ca and MgZn_(2)phases were calculated,the bulk moduli,shear moduli,Young's moduli and Poisson's ratio were derived.The calculated results shown that MgCu_(2),Mg_(2)Ca and MgZn_(2)are all ductile phases.Among the three phases,MgCu_(2)has the strongest stiffness and the plasticity of MgZn_(2)phase is the best.The density of states(DOS),Mulliken electron occupation number and charge density difference of MgCu_(2),Mg_(2)Ca and MgZn_(2)phases were discussed to analyze the mechanism of structural stability and mechanical properties.Pingli Mao Bo Yu Zheng Liu Feng Wang Yang Ju 2013Journal of Magnesium and Alloys2013,1,3:7
5Dynamic tensile properties and microstructural evolution of extruded EW75 magnesium alloy at high strain rates显示文摘The dynamic tensile properties and microstructural evolution of an extruded EW75 magnesium alloy deformed at ambient temperature and different high strain rates(from 1000 to 3000 s^(-1))along extrusion direction(ED)were investigated by Split Hopkinson Tension Bar(SHTB).The corresponding deformation mechanisms,texture evolution and microstructure changes were analyzed by optical microscope(OM),electron backscatter diffraction(EBSD)and transmission electron microscope(TEM).The results show that the extruded EW75 magnesium alloy along ED exhibits a conventional positive strain rate sensitivity that the dynamic flow stresses increase with in creasing strain rate.Texture measurements show that after dynamic tension,the initial weak texture of extruded EW75 magnesium alloy tansforms to a relatively strong<10-10>//ED texture with increasing strain rates.The microstructural analysis demonstrates that dislocation motion are main deformatin mode to accommodate dynamic tensile deformation at high strain rates.In addition,the interactions of dislocation-dislocation and dislocation-second phase lead to the in crease of flow stress and strain hardening with increasing strain rate.Jincheng Yu Bo Song Dabiao Xia Xun Zeng Yuanding Huang Norbert Hort Pingli Mao Zheng Liu 2020Journal of Magnesium and Alloys2020,8,3:7
6Pinpointing Source of Mekong and Measuring Its Length Through Analysis of Satellite Imagery and Field Investigations显示文摘For centuries, explorers and scientists from different countries had made their own conclusions on the source of the Mekong. However, the geographic source of the Mekong is still arguable because of the complexity of the Mekong source water system, inaccessible environment and the varied technologies used by those explorers and scientists. The satellite remote sensing technology has been used to pinpoint the source of the Mekong, associated with the on-the-spot investigations made by the authors in June 1999 and September 2002. The actual length of the Mekong has also been calculated.LIU Shaochuang LU Pingli LIU Donghui JIN Peidong 2007Geo-Spatial Information Science2007,10,1:6
7Experimental study on influencing factors of acid-fracturing effect for carbonate reservoirs显示文摘Acid fracturing treatment is the key technique for stimulation and stable production in carbonate reservoirs.In order to improve the carbonate reservoirs acid fracturing effect,in this paper,with a large number of experiments as the main research methods,study on influencing factors of acidfracturing effect for carbonate reservoirs from increase the effective distance of living acid,increase acid corrosion eched fracture conductivity,reduce the acid fluid loss,etc.The effective distances of live acid calculated with reacted acid limitations measured in different acid systems are quite different from those calculated according to previous standard.Fracture conductivity is one of the key parameters that affects acid fracturing effects,but it's difficult to be predicted accurately due to the strong randomness of acid-rock reaction as well as various influence factors.Analyses of the impacts on fracture conductivity resulted from the rock embedment intensity,closure stress,acid dosage,rock-acid contact time,acid fluid loss,acid pumping rate through self-developed small-core fracture capacity test instrument.Fluid loss during acid fracture can be well controlled by thickened liquid as well as solid particles,but formation damage occurs inevitably.Foamed acid is a specific fluid with high viscosity,low fluid loss,small friction resistance,good retarding property,strong fracture making ability,easy flowback and low damage,which is an ideal acid system for low pressure and low permeability carbonate reservoirs.In this paper,the theoretical study on percolation mechanism and fluid-loss control mechanism of foam(acid)in porous medium are presented with the help of visual microscopic model fluid drive unit.Nianyin Li Jinxin Dai Pingli Liu Zhifeng Luo Liqiang Zhao 2015Petroleum2015,1,2:5
8Optimal dietary copper requirements and relative bioavailability for weanling pigs fed either copper proteinate or tribasic copper chloride显示文摘Background: The objective of this study was to determine the effects of supplementing Cu on growth performance, Cu metabolism and Cu-related enzyme activities of weanling pigs fed diets with two different Cu sources, and to estimate optimal Cu requirements and relative bioavailability from these two sources for pigs.Methods: Weanling pigs were allocated to 14 treatments arranged factorially, including 6 added Cu levels(5, 10,20, 40, 80, 160 mg/kg), and 2 mineral sources(tribasic Cu chloride, TBCC and copper proteinate, Cu Pro), as well as one negative control(0 mg/kg added Cu level) and one maximum allowed level treatment(200 mg/kg TBCC) for the entire 38-d experiment. Growth performance, mineral status and enzyme activities were measured at the end of this study.Results: Increasing levels of Cu showed linear and quadratic responses(P < 0.01) for final BW, ADG and FCR regardless of the sources. Supplementation with TBCC(> 80 mg/kg) and Cu Pro(> 20 mg/kg) significantly decreased(P < 0.05) diarrhea incidence of weanling pigs. There were linear and quadratic increases(P < 0.01) in bile, hepatic,and intestinal Cu concentrations, fecal Cu contents, and plasma enzyme activities(alkaline phosphatase,ceruloplasmin, Cu, Zn-Superoxide dismutase(Cu/Zn SOD), and glutathione peroxidase), whereas plasma malondialdehyde decreased(P < 0.01) linearly and quadratically as dietary Cu level increased. Similarly, pigs fed Cu Pro absorbed and retained more Cu and excreted less Cu than those fed TBCC when supplemented 80 mg/kg and above. Optimal dietary Cu requirements for pigs from 28 to 66 d of age estimated based on fitted broken-line models(P < 0.05) of bile Cu, plasma Cu/Zn SOD and growth performance were 93–140 mg/kg from TBCC, and 63–98 mg/kg from Cu Pro accordingly. According to slope ratios from multiple linear regression, the bioavailability value of Cu Pro relative to TBCC(100%) was 156–263%(P < 0.01).Conclusion: The findings indicated that Cu recommendation from current NRC(5–6 mg/kg) was not sufficient to meet the high requirement of weanling pigs. Cu from Cu Pro was significantly more bioavailable to weanling pigs than TBCC in stimulating growth and enzyme activities, decreasing diarrhea frequency and fecal Cu contents to the environment.Gang Lin Yang Guo Bing Liu Ruiguo Wang Xiaoou Su Dongyou Yu Pingli He 2020Journal of Animal Science and Biotechnology2020,11,4:5
9Attitude coordination for spacecraft formation with multiple communication delays显示文摘Communication delays are inherently present in information exchange between spacecraft and have an effect on the control performance of spacecraft formation. In this work, attitude coordination control of spacecraft formation is addressed, which is in the presence of multiple communication delays between spacecraft. Virtual system-based approach is utilized in case that a constant reference attitude is available to only a part of the spacecraft. The feedback from the virtual systems to the spacecraft formation is introduced to maintain the formation. Using backstepping control method, input torque of each spacecraft is designed such that the attitude of each spacecraft converges asymptotically to the states of its corresponding virtual system. Furthermore, the backstepping technique and the Lyapunov–Krasovskii method contribute to the control law design when the reference attitude is time-varying and can be obtained by each spacecraft. Finally, effectiveness of the proposed methodology is illustrated by the numerical simulations of a spacecraft formation.Guo Yaohua Lu Pingli Liu Xiangdong 2015Chinese Journal of Aeronautics2015,28,2:4
10Identification of key gene networks controlling organic acid and sugar metabolism during watermelon fruit development by integrating metabolic phenotypes and gene expression profiles显示文摘The organoleptic qualities of watermelon fruit are defined by the sugar and organic acid contents,which undergo considerable variations during development and maturation.The molecular mechanisms underlying these variations remain unclear.In this study,we used transcriptome profiles to investigate the coexpression patterns of gene networks associated with sugar and organic acid metabolism.We identified 3 gene networks/modules containing 2443 genes highly correlated with sugars and organic acids.Within these modules,based on intramodular significance and Reverse Transcription Quantitative polymerase chain reaction(RT-qPCR),we identified 7 genes involved in the metabolism of sugars and organic acids.Among these genes,Cla97C01G000640,Cla97C05G087120 and Cla97C01G018840(r^(2)=0.83 with glucose content)were identified as sugar transporters(SWEET,EDR6 and STP)and Cla97C03G064990(r^(2)=0.92 with sucrose content)was identified as a sucrose synthase from information available for other crops.Similarly,Cla97C07G128420,Cla97C03G068240 and Cla97C01G008870,having strong correlations with malic(r^(2)=0.75)and citric acid(r^(2)=0.85),were annotated as malate and citrate transporters(ALMT7,CS,and ICDH).The expression profiles of these 7 genes in diverse watermelon genotypes revealed consistent patterns of expression variation in various types of watermelon.These findings add significantly to our existing knowledge of sugar and organic acid metabolism in watermelon.Muhammad Jawad Umer Luqman Bin Safdar Haileslassie Gebremeskel Shengjie Zhao Pingli Yuan Hongju Zhu M.O.Kaseb Muhammad Anees Xuqiang Lu Nan He Chengsheng Gong Wenge Liu 2020Horticulture Research2020,7,1:4
11Influences of Ca and Y Addition on the Microstructure and Corrosion Resistance of Vacuum Die-Cast AZ91 Alloy显示文摘The influences of Ca and Y additions on the microstructure and corrosion resistance of vacuum die-cast AZ91 alloys were investigated by optical microscope,electron scanning microscope,weight-loss test,and electrochemical corrosion experiment.The results indicate that the Ca or Ca and Y additions refined the microstructure and decreased the amount of Mg17Al12 phase on grain boundaries in the alloys.Meanwhile,the addition of Ca and Y led to the formation of network Al2 Ca phase and rod-like Al2 Y phase,improved the corrosion resistance of AZ91 magnesium alloy.Compared with AZ91 alloy,the corrosion rate of AZ91–1.5Ca–1.0Y alloy was decreased to 16.2%,and its corrosion current density was dropped by one order of magnitude after immersion in 3.5 wt% NaCl solution for 24 h.Feng Wang Jibao Li Jing Liu Dan Lv Pingli Mao Zheng Liu 2014Acta Metallurgica Sinica(English Letters)2014,27,4:4
12Feasibility study on application of volume acid fracturing technology to tight gas carbonate reservoir development显示文摘How to effectively develop tight-gas carbonate reservoir and achieve high recovery is always a problem for the oil and gas industry.To solve this problem,domestic petroleum engineers use the combination of the successful experiences of North American shale gas pools development by stimulated reservoir volume(SRV)fracturing with the research achievements of Chinese tight gas development by acid fracturing to propose volume acid fracturing technology for fractured tightgas carbonate reservoir,which has achieved a good stimulation effect in the pilot tests.To determine what reservoir conditions are suitable to carry out volume acid fracturing,this paper firstly introduces volume acid fracturing technology by giving the stimulation mechanism and technical ideas,and initially analyzes the feasibility by the comparison of reservoir characteristics of shale gas with tight-gas carbonate.Then,this paper analyzes the validity and limitation of the volume acid fracturing technology via the analyses of control conditions for volume acid fracturing in reservoir fracturing performance,natural fracture,horizontal principal stress difference,orientation of insitu stress and natural fracture,and gives the solution for the limitation.The study results show that the volume acid fracturing process can be used to greatly improve the flow environment of tight-gas carbonate reservoir and increase production;the incremental or stimulation response is closely related with reservoir fracturing performance,the degree of development of natural fracture,the small intersection angle between hydraulic fracture and natural fracture,the large horizontal principal stress difference is easy to form a narrow fracture zone,and it is disadvantageous to create fracture network,but the degradable fiber diversion technology may largely weaken the disadvantage.The practices indicate that the application of volume acid fracturing process to the tight-gas carbonate reservoir development is feasible in the Ordovician Majiagou Formation of lower Paleozoic,which is of great significance and practical value for domestic tight-gas carbonate reservoir development and studies in the future.Nianyin Li Jinxin Dai Chao Liu Pingli Liu Yanming Zhang Zhifeng Luo Liqiang Zhao 2015Petroleum2015,1,3:4
13Technical status and challenges of shale gas development in Sichuan Basin,China显示文摘During the past decade,shale gas developments have changed the energy structure in the US natural gas industry,and the exploration activities for shale gas are also increasing worldwide.According to the papers published in recent years,shale gas resources are quite abundant in China.With the successful experience obtained from North America,many state-of-the-art technologies are brought in and refined for field application.State-owned enterprise,private enterprises and foreign enterprises have all actively participated in the exploitation of shale gas.Compared with US,China faces many more challenges,both geological and above-ground,in the development of shale gas resources.This paper begins with the introduction of shale gas reserve distribution in China and the identified shale gas formation in Sichuan Basin.The following paper reviews the methodology employed in the geophysical prospecting,drilling and completion,and hydraulic fracturing process.Since China is in the early stage of shale gas development,there is a great technical gap between China and North America.Based on literature review,the major challenges faced in the exploration and production process are identified.What presented in this paper should be of particular interest to the personnels involved in shale gas production in China and countries that are about to set foot in shale gas business.It will also be of interest to researchers who are dedicated to developing these technologies to unlock unconventional gas resources in China.Pingli Liu Yinsheng Feng Liqiang Zhao Nianyin Li Zhifeng Luo 2015Petroleum2015,1,1:3
14Deformation mechanism of fine grained Mg-7Gd-5Y-l.2Nd-0.5Zr alloy under high temperature and high strain rates显示文摘Fine grained Mg-7Gd-5Y-1.2Nd-0.5Zr alloy was investigated by dynamic compression tests using a Split Hopkinson Pressure Bar under the strain rates in the range 1000-2000 s^(-1) and the temperature range 293-573 K along the normal direction.The microstructure was measured by optical microscopy,electron back-scattering diffraction,transmission electron microscopy and X-ray diffractometry.The results showed that Mg-7Gd-5Y-1.2Nd-0.5Zr alloy had the positive strain rate strengthening effect and thermal softening effect at high temperature.The solid solution of Gd and Y atoms in Mg-7Gd-5Y-1.2Nd-0.5Zr alloy reduced the asymmetry of α-Mg crystals and changed the critical shear stress of various deformation mechanisms.The main deformation mechanisms were prismatic slip and pyramidal(a)slip,{102}tension twinning,and dynamic recrystallization caused by local deformation such as particle-stimulated nucleation.c 2020 Published by Elsevier B.V.on behalf of Chongqing University.Wanru Tang Zheng Liu Shimeng Liu Le Zhou Pingli Mao Hui Guo Xiaofang Sheng 2020Journal of Magnesium and Alloys2020,8,4:2
15Simultaneous determination of fifteen illegal dyes in animal feeds and poultry products by ultra-high performance liquid chromatography tandem mass spectrometry显示文摘Rongyuan Liu Wenjing Hei Pingli He Zhen Li 2011Journal of Chromatography B2011,,24:2
16Hot Tearing Susceptibility of AXJ530 Alloy Under Low-Frequency Alternating Magnetic Field显示文摘Herein, a hot tearing measured system with external excitation coil and a differential thermal analysis system with applied magnetic field were used to study the effects of low-frequency alternating magnetic field on the solidification behavior and hot tearing susceptibility(HTS) of the AXJ530 alloy under different magnetic field parameters. The hot tearing volume of the castings was measured via paraffin infiltration method. The microstructure of the hot tearing zone of the casting was observed using optical microscopy and scanning electron microscopy, and the phase composition was analyzed using X-ray diffraction and energy depressive spectroscopy. The experimental results show that the solidification interval of AXJ530 alloy was shortened and the dendrite coherency temperature of the alloy decreased with the increase in frequency of alternating magnetic field. Under appropriate magnetic field parameters, the electromagnetic force could enhance the convection in the melt to promote the flow of the residual liquid phase, refine the microstructure, and optimize the feeding channel in the late solidification stage, which reduced the HTS of the alloy. However, when the magnetic field frequency was increased to 15 Hz, the induced current generated excessive Joule heat to the melt. At this time, the thermal action of the magnetic field coarsened the microstructure of the alloy, resulting in an increase in HTS of the alloy.Xudong Du Feng Wang Zhi Wang Xingxing Li Zheng Liu Pingli Mao 2020Acta Metallurgica Sinica(English Letters)2020,33,9:1
17Enhancing the short-circuit current and efficiency of organic solar cells using MoO 3 and CuPc as buffer layers显示文摘Fei Cheng Guojia Fang Xi Fan Nishuang Liu Nanhai Sun Pingli Qin Qiao Zheng Jiawei Wan Xingzhong Zhao 2011Solar Energy Materials and Solar Cells2011,,10:1
18Study and application of a new blockage remover in polymer injection wells显示文摘With the extensive application of polymer flooding technology in offshore oilfields,the plugging in polymer injection wells has become more and more severe,which seriously affects the oil displacement effect and regular production of oilfields.In this paper,a new kind of blockage remover has been developed and evaluated by rheological behavior experiments,dissolution experiments and core flooding experiments.The results reveal that this new blockage remover can effectively reduce the viscosity of polymer and completely degrade the reservoir blockage with low corrosion rate.It is beneficial to long-term production of oil wells in offshore oilfield.Results of core flooding experiments show that this new blockage remover can relieve polymer damage and improve permeability.The agent has been applied in LD10-1 oilfield in 2016,the daily injection rate increased significantly after stimulation.Yiyong Pan Changlong Liu Liqiang Zhao Feng Li Yigang Liu Pingli Liu 2018Petroleum2018,4,3:1
19Research and application of low permeability oil reservoir fracturing fluid显示文摘LIU Pingli ZHANG Lu XING Xijin 2014Oilfield Chemistry2014,31,3:1
20Polysulfone(PSF)composite membrane with micro-reaction locations (MRLs) made by doping sulfated TiO2 deposited on SiO2 nanotubes (STSNs)for cleaning wastewater 显示文摘Zhang Yuqing Liu Pingli 2015Journal of Membrane Science2015,493,:1
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