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| 1 | Effects of livestock exclusion and climate change on aboveground biomass accumulation in alpine pastures across the Northern Tibetan Plateau显示文摘To better understand the ecological and economic benefits of short-term grazing exclusion on the aboveground net primary productivity(ANPP)of alpine pastures,we conducted annual multi-site transect surveys in the summers from 2009 to 2011 and calculated the aboveground biomass discrepancy(ABD)between grazed and ungrazed pastures at plant community and economic group levels for three zonal alpine grassland types—meadow,steppe,and desert-steppe—across the northern Tibetan Plateau.Our results indicated that aboveground biomass(AGB)significantly differed among grassland types and declined northwesterly from 64.07 to11.44 g m-2with decreasing precipitation and increasing temperature.The mean ABD exhibited considerable community dependency,with meadow(12.47 g m-2)[steppe(6.91 g m-2)[desert steppe(2.54 g m-2),and it declined from 25.42 to 1.29 g m-2with decreasing precipitation and increasing temperature.‘Good forage’,i.e.grasses and sedges,benefited most from grazing exclusion,followed by edible forbs.With longer grazing exclusion durations(GEDs),the aboveground biomass of poisonous locoweeds initially decreased and then increased compared with the adjacent grazed sites.In the nested analysis of co-variances with a general linear model,growing season precipitation(GSP;from May to September)accounted for 52.67%ofthe observed variation in AGB,followed by AGT(9.77%)and pasture management systems(PMSs;grazing or grazing-excluded,5.31%).The variation in ABD was explained primarily by AGT(16.52%),GED(20.25%),and the interaction of AGT 9 GED(19.58%).Our results confirm that precipitation is the primary factor controlling the ANPP of alpine grasslands on the Northern Tibetan Plateau and that the ecological benefits arising from grazing exclusion are also partly dependent on grassland type and exclusion duration.Therefore,spatial and temporal variations in growing season precipitation and plant functional traits or economic group composition should be jointly considered when developing policies concerning the management and spatial layouts of grazing exclosures in this region. | Jianshuang Wu Xianzhou Zhang Zhenxi Shen Peili Shi Chengqun Yu Baoxiong Chen | 2014 | Chinese Science Bulletin2014，59，32： | 11 |
| 2 | Abiogenic hydrocarbons in commercial gases from the Songliao Basin,China显示文摘This paper discusses the kinetic fractionation, composition and distribution characteristics of carbon and hydrogen isotopes for various alkane gases formed in different environments, by different mecha- nisms and from different sources in nature. It is demonstrated that the biodegradation or thermode- gradation of complex high-molecule sedimentary organic material can form microbial gas or thermogenic gas. The δ 13C1 value ranges from -110‰ to -50‰ for microbial gases but from -50‰ to -35‰ (even heavier) for thermogenic gases. Controlled by the kinetic isotope fractionation, both microbial and thermogenic gases have δ 13C and δ D values characterized by normal distribution, i.e. δ 13C1< δ 13C2< δ 13C3< δ 13C4 and δ DCH4< δ DC2H6< δ DC3H8<δ DC4H10, and by a positive correlation between the δ 13C and δ D values. Simple carbonbearing molecules (CH4, CO and CO2) can form abiogenic alkane gases via polymerization in the abiological chemical process in nature, with δ 13C1 heavier than -30‰. Moreover, controlled by the kinetic isotope fractionation, abiogenic alkane gases are characterized by a reverse distribution of δ 13C values and a normal trend of δ D values, namely δ 13C1> δ 13C2> δ 13C3> δ 13C4 and δ DCH4<δ DC2H6< δ DC3H8< δ DC4H10. The δ 13C values and δ D values are negatively correlated. Natural gases from 26 commercial gas wells distributed in the Xujiaweizi and Yingshan-Miaotaizi faulted depressions in the Songliao Basin, China, show δ13C1 values ranging from -30.5‰ to -16.7‰ with a very narrow δ D range between -203‰―-196‰. These gases are characterized by a reverse distribution of δ 13C values but a normal distribution of δ D values, and a negative correlation between their δ 13C and δ D values, indicating an abiological origin. The present study has revealed that abiogenic hydrocarbons not only exist in nature but also can make significant contribution to commercial gas reserviors. It is estimated that the reserve volume of alkane gases with abiogenic characteristics in these 26 gas wells in the Songliao Basin is over 500×108 m3. The prospecting practice in the Songliao Basin has demonstrated that abiogenic alkane gases are of a promising resource, and it provides an example for the investigation of and search for abiogenic commercial natural gases worldwide. | WANG XianBin GUO ZhanQian TUO JinCai GUO HongYan LI ZhenXi ZHUO ShengGuang JIANG HongLiang ZENG LongWei ZHANG MingJie WANG LianSheng LIU ChunXue YAN Hong LI LiWu ZHOU XiaoFeng WANG YongLi YANG Hui WANG Guang | 2009 | Science China Earth Sciences2009，52，2： | 6 |
| 3 | Vibration signal-based chatter identification for milling of thin-walled structure显示文摘In high speed milling aeronautical part,tool condition monitoring(TCM)is very important,because it is prone to get a chatter owing to the low stiffness of thin-walled structures.And the TCM is key technology for automated machining.In this paper,aiming to chatter monitoring in thin-walled structure milling,a variational mode decomposition–energy distribution(VMD-ED)method is proposed to improve the identification accuracy.And a moving average root mean square–mean value(MARMS-MV)identification method and a variational mode decomposition–energy entropy(VMD-EE)identification method are also tested.Identification accuracy and computing time of the three methods are compared.The vibration signals collected from the spindle and worktable are also contrasted.The conducted experimental study shows that,the proposed VMD-ED method offers an identification method for chatter monitoring with greater sensitivity,better stability and less computing time,and mounting the vibration sensor on worktable is better than spindle for a chatter monitoring system. | Wenping MOU Shaowei ZHU Zhenxi JIANG Ge SONG | 2022 | Chinese Journal of Aeronautics2022，35，1： | 3 |
| 4 | Geochemistry of Palaeozoic marine petroleum from the Tarim Basin, NW China: Part 3. Thermal cracking of liquid hydrocarbons and gas washing as the major mechanisms for deep gas condensate accumulations显示文摘 | Shuichang Zhang Jin Su Xiaomei Wang Guangyou Zhu Haijun Yang Keyu Liu Zhenxi Li | 2011 | Organic Geochemistry2011，，： | 2 |
| 5 | Axonal autophagy during regeneration of the rat sciatic nerve显示文摘BACKGROUND: The removal of degenerated axonal debris during Wallerian degeneration is very important for nerve regeneration. However, the mechanism by which debris is removed is not been completely understood. Considerable controversy remains as to the clearance pathway and cells that are involved. OBJECTIVE: To investigate axonal autophagy during removal of degenerated axonal debris by transecting the sciatic nerve in a rat Wallerian degeneration model. DESIGN, TIME AND SETTING: Experimental neuropathological analysis. The experiment was conducted at the Laboratory Animal Service Center of the Southern Medical University between January and June 2005. MATERIALS: Fifty-four adult, Wistar rats of either sex, weighing 180-250 g, were obtained from the Laboratory Animal Service Center of the Southern Medical University. Animals were randomly divided into nine groups of six rats. METHODS: Wallerian degeneration was induced by transecting the rat sciatic nerve, and tissue samples from the distal stump were obtained 0.2, 0.4, 1, 2, 3, 4, 7, 10, and 15 days post-transection. Ultrathin sections were prepared for electron microscopy to study ultrastructure and enzyme cytochemistry staining. MAIN OUTCOME MEASURES: Ultrastructure (axon body, autophagic body, and cystoskeleton) of axons and myelin sheaths observed with electron microscopy; acidic phosphatase activity detected by Gomori staining using electron microscopy. RESULTS: The major changes of degenerating axons after transection were axoplasm swelling and separation of axons from their myelin sheath between five hours and two days post-transection. At four days post-transection, the axoplasm condensed and axons were completely separated from the myelin sheath, forming dissociative axon bodies. Vacuoles of different sizes formed in axons during the early phase after lesion. Larger dissociative axon bodies were formed when the axons were completely separated from the myelin sheath during a late phase. The axolemma surrounding the axon body was derived from the neuronal cell membrane; the condensed axoplasm contained many autophagic vacuoles at all levels. A large number of neurofilaments, microtubules, and microfilaments were arranged in a criss-cross pattern. The autophagic vacuoles exhibited acidic phosphatase activity. Axonal bodies were absorbed after degradation from day 7 onwards, and macrophages were observed rarely in the formative cavity. CONCLUSION: The degenerating axons were cleared mainly by axonal autophagy and Schwann cell phagocytosis during regeneration of the rat sciatic nerve, and macrophages exhibited only an assisting function. | Kangrong Lu Zhongxian Piao Zhenxi Liu Weiwang Gu Wanshan Wang Yingjie Piao | 2008 | Neural Regeneration Research2008，3，6： | 2 |
| 6 | Small molecule 1′-acetoxychavicol acetate suppresses breast tumor metastasis by regulating the SHP-1/STAT3/MMPs signaling pathway显示文摘 | Jieqiong Wang Li Zhang Guoliang Chen Jing Zhang Zhenxi Li Weiqiang Lu Mingyao Liu Xiufeng Pang | 2014 | Breast Cancer Research and Treatment2014，，2： | 2 |
| 7 | A new algorithm for detecting fetal heart rate using ultrasound Doppler signal显示文摘 | Xiao Hua Luo Kaiqin Zhang Zhenxi | 2005 | Ultrasonics2005，43，6： | 1 |
| 8 | Materials Science and Engineering A 显示文摘 | Cao Jingxia Bai Fang Li Zhenxi | 2006 | 424(1-2):472006，424，12： | 1 |
| 9 | Materials Science and Engineering A显示文摘 | Cao Jingxia Bai Fang Li Zhenxi | 2006 | 424(1-2):472006，424，12： | 1 |
| 10 | A no-vel biomaterial-Fe3 O 4:TiO 2 core-shell nanoparticle with magnetic performance and high visible lighttphotocatalytic activity显示文摘 | He Qinghang Zhang Zhenxi Xiong Jianwen | | 0，，： | 1 |
| 11 | Investigation of phase evolution during the therrnochemical synthesis of tricalcium phosphate显示文摘 | Niu Jinlong Zhang Zhenxi Jiang Dazong | 2001 | Journal of Materials synthesis and Processing2001，9，5： | 1 |
| 12 | Geochemical characteristics of aromatic hydrocarbons of crude oils and source rocks from different sedimentary enviroments显示文摘 | Fan Pu Philp R P Li Zhenxi | 1990 | Organic Geochemistry1990，16，： | 1 |
| 13 | Malic enzyme 2 as a therapeutic target for cancer: comments on ‘Malic enzyme 2 maintains protein stability of mutant p53 through 2-hydroxyglutarate’显示文摘In mammalian cells,there are three isoformsof malicenzymes(MEs):a cytosolic nicotinamide adenine dinucleotide phosphate*(NADP+)dependent isoform(ME1),a mitochondrial NADP+-dependent isoform(ME2),and a mitochondrial NADp+-dependent isoform(ME3),of which ME1 and ME2 are the major isoforms.As essential modulators of metabolism and aging,MEs havebeen reported to be targetsfor wild-type p53(wtp53),which can transcriptionally repress their expression.Reciprocally,downregulation of ME1 and ME2leads to wtp53activation via distinct mechanisms(iang et al.,2013;Figure 1A). | Zhenxi Zhang Wenjing Du | 2022 | Journal of Molecular Cell Biology2022，14，4： | 1 |
| 14 | Stress-induced interaction between p38 MAPK and HSP70显示文摘 | Xiaowei Gong Tingting Luo Peng Deng Zhenxi Liu Jiancheng Xiu Hongqin Shi Yong Jiang | 2012 | Biochemical and Biophysical Research Communications2012，，2： | 1 |
| 15 | Effects of the particle Stokes number on wind turbine airfoil erosion显示文摘Under natural conditions, wind turbines are inevitably eroded by the action of sand-wind flow. To further investigate the effects of dust drift on the erosion of the wind turbine blades in sand-wind environments, the effects of the wind velocity, particle diameter, and particle density on the erosion of wind turbine airfoils are studied, and the effects of the particle Stokes number on the airfoil erosion are discussed. The results show that, when the angle of attack(AOA) is 6.1°, there will be no erosion on the airfoil surface if the particle Stokes number is lower than 0.013 5, whereas erosion will occur if the particle Stokes number is higher than 0.015 1. Therefore, there exists a critical range for the particle Stokes number. When the particle Stokes number is higher than the maximum value in the critical range, airfoil erosion will occur. The result is further confirmed by changing the particle diameter, particle density, and inflow speed. It is shown that the erosion area on the airfoil and the maximum erosion rate are almost equal under the same particle Stokes number and AOA. The extent of airfoil erosion increases when the particle Stokes number increases, and the critical particle Stokes number increases when the AOA increases. Moreover, the geometric shape of the airfoil pressure surface greatly affects the airfoil erosion, especially at the curvature near the leading edge. | Deshun LI Zhenxi ZHAO Yinran LI Qing WANG Rennian LI Ye LI | 2018 | Applied Mathematics and Mechanics(English Edition)2018，39，5： | 1 |
| 16 | Response of soil microbial biomass to short-term experimental warming in alpine meadow on the Tibetan Plateau显示文摘 | Gang Fu Zhenxi Shen Xianzhou Zhang Yuting Zhou | 2012 | Applied Soil Ecology2012，，： | 1 |
| 17 | Response of microbial biomass to grazing in an alpine meadow along an elevation gradient on the Tibetan Plateau显示文摘 | Gang Fu Zhenxi Shen Xianzhou Zhang Yuting Zhou Yangjian Zhang | 2012 | European Journal of Soil Biology2012，，： | 1 |
| 18 | Design method based on routing tree for topology update in Ad Hoc network显示文摘 | Wei Zhenxi Zhang Hong Wang Xiaoling | 2006 | Journal of Electronic Science and Technology of China2006，2，4： | 1 |
| 19 | Geochemical characteristics of aromatic hydrocarbons of crude oils and source rocks from different sedimentary environments显示文摘 | Pu F Philip R Zhenxi L | 1990 | Organic Geochemistry1990，16，1： | 1 |
| 20 | Effect of additives on microwave dielectric properties of ZnNb206 ceramics显示文摘 | Zhang Yingchun Li Longtu Yue Zhenxie | 2003 | Mater Sci Eng B2003，99，： | 1 |
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