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1China's lakes at present:Number,area and spatial distribution显示文摘Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported by 6843 digital raster images(1:100000 and 1:50000),a countrywide digital vector dataset(1:250000),and historical literature.Comparative data were corrected for seasonal variations using precipitation data.There are presently 2693 natural lakes in China with an area greater than 1.0 km2,excluding reservoirs.These lakes are distributed in 28 provinces,autonomous regions and municipalities and have a total area of 81414.6 km2,accounting for-0.9% of China's total land area.In the past 30 years,the number of newly formed and newly discovered lakes with an area greater than 1.0 km2 is 60 and 131,respectively.Conversely,243 lakes have disappeared in this time period.MA RongHua YANG GuiShan DUAN HongTao JIANG JiaHu WANG SuMin FENG XueZhi LI AiNong KONG FanXiang XUE Bin WU JingLu LI ShiJie 2011Science China Earth Sciences2011,54,2:79
2State-of-the-art review on frequency response of wind power plants in power systems显示文摘With an increasing penetration of wind power in the modern electrical grid, the increasing replacement of large conventional synchronous generators by wind power plants will potentially result in deteriorated frequency regulation performance due to the reduced system inertia and primary frequency response. A series of challenging issues arise from the aspects of power system planning,operation, control and protection. Therefore, it is valuable to develop variable speed wind turbines(VSWTs) equipped with frequency regulation capabilities that allow them to effectively participate in addressing severe frequency contingencies. This paper provides a comprehensive surveyon frequency regulation methods for VSWTs. It fully describes the concepts, principles and control strategies of prevailing frequency controls of VSWTs, including future development trends. It concludes with a performance comparison of frequency regulation by the four main types of wind power plants.Ziping WU Wenzhong GAO Tianqi GAO Weihang YAN Huaguang ZHANG Shijie YAN Xiao WANG 2018Journal of Modern Power Systems and Clean Energy2018,6,1:26
3Sequencing of Cultivated Peanut, Arachis hypogaea, Yields Insights into Genome Evolution and Oil Improvement显示文摘Cultivated peanut (Arachis hypogaea) is an allotetraploid crop planted in Asia, Africa, and America for edible oil and protein. To explore the origins and consequences of tetraploidy, we sequenced the allotetraploid A. hypogaea genome and compared it with the related diploid Arachis duranensis and Arachis ipaensis genomes. We annotated 39 888 A-subgenome genes and 41 526 B-subgenome genes in allotetraploid peanut. The A. hypogaea subgenomes have evolved asymmetrically, with the B subgenome resembling the ancestral state and the A subgenome undergoing more gene disruption, loss, conversion, and transposable element proliferation, and having reduced gene expression during seed development despite lacking genome-wide expression dominance. Genomic and transcriptomic analyses identified more than 2 500 oil metabolism-related genes and revealed that most of them show altered expression early in seed development while their expression ceases during desiccation, presenting a comprehensive map of peanut lipid biosynthesis. The availability of these genomic resources will facilitate a better understanding of the complex genome architecture, agronomically and economically important genes, and genetic improvement of peanut.Xiaoping Chen Qing Lu Hao Liu Jianan Zhang Yanbin Hong Haofa Lan Haifen Li Jinpeng Wang Haiyan Liu Shaoxiong Li Manish K.Pandey Zhikang Zhang Guiyuan Zhou Jigao Yu Guoqiang Zhang Jiaqing Yuan Xingyu Li Shijie Wen Fanbo Meng Shanlin Yu Xiyin Wang Kadambot H.M.Siddique Zhong-Jian Liu Andrew H.Paterson Rajeev K.Varshney Xuanqiang Liang 2019Molecular Plant2019,12,7:23
4Spatial-temporal Changes of Vegetation Cover in Guizhou Province, Southern China显示文摘Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different characteristics of the spatial-temporal changes of vegetation cover in Guizhou Province of Southern China using the data set of SPOT VEGETATION(1999–2015) at spatial resolution of 1-km and temporal resolution of 10-day. The coefficient of variation, the Theil-Sen median trend analysis, and the Mann-Kendall test are used to investigate the spatial-temporal change of vegetation cover and its future trend. Results show that: 1) the spatial distribution pattern of vegetation cover in Guizhou Plateau is high in the east whereas low in the west. The average annual normalized difference vegetation index(NDVI) from west to east is higher than that from south to north. 2) Average annual NDVI improved obviously in the past 17 years. The growth rate of average annual NDVI is 0.028/10 yr, which is slower than that of vegetation in the country(0.048/10 yr) from 1998 to 2007. Average annual NDVI in karst area is lower than that in non-karst area. However, the growing rate of average annual NDVI in karst area(0.030/10 yr) is faster than that in non-karst area(0.023/10 yr), indicating that vegetation coverage increases more rapidly in karst area. 3) Vegetation coverage in the study area is stable overall, but fluctuates in the local scales. 4) Vegetation coverage presents a continuous increasing trend. The Hurst exponent of NDVI in different vegetation types has an obvious threshold in various elevations. 5) The proportion of vegetation cover with sustainable increase is higher than that of vegetation cover with sustainable decrease. The improvement in vegetation cover may expand to most parts of the study area.TIAN Yichao BAI Xiaoyong WANG Shijie QIN Luoyi LI Yue 2017Chinese Geographical Science2017,27,1:21
5Climate and litter C/N ratio constrain soil organic carbon accumulation显示文摘Soil organic carbon(SOC) plays critical roles in stabilizing atmospheric CO2 concentration, but the mechanistic controls on the amount and distribution of SOC on global scales are not well understood. In turn, this has hampered the ability to model global C budgets and to find measures to mitigate climate change. Here, based on the data from a large field survey campaign with 2600 plots across China’s forest ecosystems and a global collection of published data from forested land, we find that a low litter carbon-to-nitrogen ratio(C/N) and high wetness index(P/PET, precipitation-to-potentialevapotranspiration ratio) are the two factors that promote SOC accumulation, with only minor contributions of litter quantity and soil texture. The field survey data demonstrated that high plant diversity decreased litter C/N and thus indirectly promoted SOC accumulation by increasing the litter quality. We conclude that any changes in plant-community composition, plant-species richness and environmental factors that can reduce the litter C/N ratio, or climatic changes that increase wetness index, may promote SOC accumulation. The study provides a guideline for modeling the carbon cycle of various ecosystem scales and formulates the principle for land-based actions for mitigating the rising atmospheric CO2 concentration.Guoyi Zhou Shan Xu Philippe Ciais Stefano Manzoni Jingyun Fang Guirui Yu Xuli Tang Ping Zhou Wantong Wang Junhua Yan Gengxu Wang Keping Ma Shenggong Li Sheng Du Shijie Han Youxin Ma Deqiang Zhang Juxiu Liu Shizhong Liu Guowei Chu Qianmei Zhang Yuelin Li Wenjuan Huang Hai Ren Xiankai Lu Xiuzhi Chen 2019National Science Review2019,6,4:21
6Enhanced mechanical properties and degradation rate of Mg-Ni-Y alloy by introducing LPSO phase for degradable fracturing ball applications显示文摘In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order(LPSO)phase was firstly introduced to improve both the mechanical properties and degradation rate of magnesium alloys.With the increase of LPSO phase,the compressive strength was improved significantly,while the elongation of the alloys decreased owing to the relatively brittle nature of LPSO phase.Due to the higher corrosion potential of LPSO phase,the LPSO phase can accelerate the corrosion process by providing more micro-couples.However,the LPSO phase would serve as the corrosion barrier between the corrosion medium and the matrix when the contents of LPSO phase are too high in Mg92.5Ni3Y4.5 and Mg87.5Ni5Y7.5 alloys.As-cast Mg97.5Ni1Y1.5 alloy with satisfactory mechanical properties and rapid degradation rate was successfully developed,exhibiting a high degradation rate of 6675 mm/a(93℃)in 3 wt.%KCl solution and a favorable ultimate compressive strength of 410 MPa.The degradation rate of Mg97.5Ni1Y1.5 alloy is 2-5 times of the current commercial magnesium alloy fracturing materials.Jingfeng Wang Shiqing Gao Xiuying Liu Xing Peng Kui Wang Shijie Liu Weiyan Jiang Shengfeng Guo Fusheng Pan 2020Journal of Magnesium and Alloys2020,8,1:13
7Insight-HXMT observations of the first binary neutron star merger GW170817显示文摘Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017,Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart,GRB 170817 A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope(HE) onboard Insight-HXMT(Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart(SSS17 a/AT2017 gfo) with very large collection area(~1000 cm^2) and microsecond time resolution in 0.2-5 MeV. In addition,Insight-HXMT quickly implemented a Target of Opportunity(ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy(0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817 A. Meanwhile,Insight-HXMT/HE provides one of the most stringent constraints(~10^(-7) to 10^(-6) erg/cm^2/s) for both GRB170817 A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.TiPei Li ShaoLin Xiong ShuangNan Zhang FangJun Lu LiMing Song XueLei Cao Zhi Chang Gang Chen Li Chen TianXiang Chen Yong Chen YiBao Chen YuPeng Chen Wei Cui WeiWei Cui JingKang Deng YongWei Dong YuanYuan Du MinXue Fu GuanHua Gao He Gao Min Gao MingYu Ge YuDong Gu Ju Guan ChengCheng Guo DaWei Han Wei Hu Yue Huang Jia Huo ShuMei Jia LuHua Jiang WeiChun Jiang Jing Jin YongJie Jin Bing Li ChengKui Li Gang Li MaoShun Li Wei Li Xian Li XiaoBo Li XuFang Li YanGuo Li ZiJian Li ZhengWei Li XiaoHua Liang JinYuan Liao CongZhan Liu GuoQing Liu HongWei Liu ShaoZhen Liu XiaoJing Liu Yuan Liu YiNong Liu Bo Lu XueFeng Lu Tao Luo Xiang Ma Bin Meng Yi Nang JianYin Nie Ge OU JinLu Qu Na Sai Liang Sun Yin Tan Lian Tao WenHui Tao YouLi Tuo GuoFeng Wang HuanYu Wang Juan Wang WenShuai Wang YuSa Wang XiangYang Wen BoBing WU Mei Wu GuangCheng Xiao He Xu YuPeng Xu LinLi Yan JiaWei Yang Sheng Yang YanJi Yang AiMei Zhang ChunLei Zhang ChengMo Zhang Fan Zhang HongMei Zhang Juan Zhang Qiang Zhang Shu Zhang Tong Zhang Wei Zhang WanChang Zhang WenZhao Zhang Yi Zhang Yue Zhang YiFei Zhang YongJie Zhang Zhao Zhang ZiLiang Zhang HaiSheng Zhao JianLing Zhao XiaoFan Zhao ShiJie Zheng Yue Zhu YuXuan Zhu ChangLin Zou 2018Science China(Physics,Mechanics & Astronomy)2018,61,3:12
8The enhanced X-ray Timing and Polarimetry mission—eXTP显示文摘In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.ShuangNan Zhang Andrea Santangelo Marco Feroci YuPeng Xu FangJun Lu Yong Chen Hua Feng Shu Zhang Sφren Brandt Margarita Hernanz Luca Baldini Enrico Bozzo Riccardo Campana Alessandra De Rosa YongWei Dong Yuri Evangelista Vladimir Karas Norbert Meidinger Aline Meuris Kirpal Nandra Teng Pan Giovanni Pareschi Piotr Orleanski QiuShi Huang Stephane Schanne Giorgia Sironi Daniele Spiga Jiri Svoboda Gianpiero Tagliaferri Christoph Tenzer Andrea Vacchi Silvia Zane Dave Walton ZhanShan Wang Berend Winter Xin Wu Jean J.M.in't Zand Mahdi Ahangarianabhari Giovanni Ambrosi Filippo Ambrosino Marco Barbera Stefano Basso Jörg Bayer Ronaldo Bellazzini Pierluigi Bellutti Bruna Bertucci Giuseppe Bertuccio Giacomo Borghi XueLei Cao Franck Cadoux Francesco Ceraudo TianXiang Chen Yu Peng Chen Jerome Chevenez Marta Civitani Wei Cui WeiWei Cui Thomas Dauser Ettore Del Monte Sergio Di Cosimo Sebastian Diebold Victor Doroshenko Michal Dovciak YuanYuan Du Lorenzo Ducci QingMei Fan Yannick Favre Fabio Fuschino JoséLuis Ga'lvez Min Gao MingYu Ge Olivier Gevin Marco Grassi QuanYing Gu YuDong Gu DaWei Han Bin Hong Wei Hu Long Ji ShuMei Jia WeiChun Jiang Thomas Kennedy Ingo Kreykenbohm Irfan Kuvvetli Claudio Labanti Luca Latronico Gang Li MaoShun Li Xian Li Wei Li ZhengWei Li Olivier Limousin HongWei Liu XiaoJing Liu Bo Lu Tao Luo Daniele Macera Piero Malcovati Adrian Martindale Malgorzata Michalska Bin Meng Massimo Minuti Alfredo Morbidini Fabio Muleri Stephane Paltani Emanuele Perinati Antonino Picciotto Claudio Piemonte JinLu Qu Alexandre Rachevski Irina Rashevskaya Jerome Rodriguez Thomas Schanz ZhengXiang Shen LiZhi Sheng JiangBo Song LiMing Song Carmelo Sgro Liang Sun Ying Tan Phil Uttley Bo Wang DianLong Wang GuoFeng Wang Juan Wang LangPing Wang YuSa Wang Anna L.Watts XiangYang Wen Jörn Wilms ShaoLin Xiong JiaWei Yang Sheng Yang YanJi Yang Nian Yu WenDa Zhang Gianluigi Zampa Nicola Zampa Andrzej A.Zdziarski AiMei Zhang ChengMo Zhang Fan Zhang Long Zhang Tong Zhang Yi Zhang XiaoLi Zhang ZiLiang Zhang BaoSheng Zhao ShiJie Zheng Yu Peng Zhou Nicola Zorzi J.Frans Zwart 2019Science China(Physics,Mechanics & Astronomy)2019,62,2:11
9Transmission of oxygen isotope signals of precipitation-soil water-drip water and its implications in Liangfeng Cave of Guizhou,China显示文摘According to systemically monitoring results of oxygen(hydrogen) isotope compositions of precipita-tion,soil waters,soil CO2,cave drip waters and their corresponding speleothems in Liangfeng Cave(LFC) in Guizhou Province,Southwest China,it is found that local precipitation is the main source of soil waters and drip waters,and that the amplitudes of those δ 18O values of three waters(precipitation,soil water and drip water) decrease in turn in the observed year,which are 0‰ to -10‰, -2‰ to -9‰ and -6‰ to -8‰,respectively.Moreover,the δ 18O values for three waters show a roughly simultaneous variation,namely,that those values are lighter in the rainy seasons,weightier in the dry seasons,and that the average δ 18O value of drip waters is about 0.3‰ weightier than that of precipitation,which is modified by surface evaporation processes.We also find that oxygen isotope equilibrium is reached or neared in the formation processes of speleothems in LFC system,and that it is feasible to reconstruct paleotemperature and paleoprecipitation by using δ 18O values of speleothems.However,it should be noted that surface evaporation would affect the oxygen isotope values in the study area.LUO WeiJun WANG ShiJie 2008Chinese Science Bulletin2008,53,21:11
10Effects of Nogo-neutralizing antibody and neurotrophin-3 on axonal regeneration following spinal cord injury in rats显示文摘BACKGROUND: Recent studies have suggested that regeneration of the central nerve fiber following spinal cord injury occurs under specific conditions. OBJECTIVE: To study the effects of Nogo-neutralizing antibody (IN-1), in combination with neurotrophin-3 (NT-3), on axonal regeneration and motor function following spinal cord injury in the rat. DESIGN, TIME AND SETTING: A randomized, controlled, animal study combining immunohistochemistry was performed at the Laboratory of Neuroanatomy of Xiangya Medical College, and Central Laboratory of Xiangya the Third Hospital, Central South University from January 2006 to December 2007. MATERIALS: Eighteen healthy, Sprague Dawley rats were randomly divided into three groups, with six rats per group: control, IN-1, and IN-1/NT-3. Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of spinal cord, which is equivalent to the T8 level. METHODS: A polyethylene tubing was inserted through into subarachnoid cavity, equivalent to the superior margin at the T8 level. Saline, IN-1, and IN-1/NT-3 were respectively injected into control, IN-1, and IN-1/NT-3 groups, three times/day for seven consecutive days. MAIN OUTCOME MEASURES: At 2 weeks post-surgery, biotin dextran amine (10%) was injected into the right sensorimotor cortex area. At day 28 post-surgery, spinal cord tissue was prepared for frozen sections. Positive astrocytic expression was observed with glial fibrillary acidic protein (GFAP) immunohistochemical staining whose proliferation level was represented by gray value, i.e. the higher the gray value was, the less the positive cells were, and growth of positive fibers was observed with a biotin dextran amine histological reaction. Motor function was measured according to BBB scores pre-operatively, as well as at days 1, 7, 14, 21, and 28 post-operatively. RESULTS: Three rats died during experimentation. By random supplement, a total of 18 rats were included. GFAP-positive astrocytes were observed in all the three groups. In the control group, astrocytes were characterized according to active function, hyperplasia, proliferation, hypertrophy, and increasing processes as compared to IN-1 group and IN-1/IN-3 group. Astrocyte hyperplasia represented by gray value in the IN-1 group was less than the control group. Gray value of GFAP-positive products in the IN-1/IN-3 group was higher than other two groups (P < 0.05). Biotin dextran amine tracing demonstrated no corticospinal tract fiber outgrowth following spinal cord injury; the fibers were incapable of passing through the glial scar in the control group. Several fibers were distributed in the proximal scar tissue region in the IN-1 group, and the regenerated fibers were disarranged. Many nerve fibers were distributed throughout the scar tissue, and even several biotin dextran amine-positive fibers were observed at the distal end of the injured segment. Post-operative Basso, Beattie, Bresnahan scores were greater than pre-operative ones, while Basso, Beattie, Bresnahan scores in the IN-1/NT-3 group were significantly greater than the other two groups at days 14, 21, and 28 post-surgery (P < 0.05). CONCLUSION: IN-1, in combination with NT-3, promoted axonal regeneration following spinal cord injury, inhibited the colloidal effect, and enhanced the correlation between proximal and distal processes to recover motor function. The recovery effect of IN-1/NT-3 on motor function was superior that of to IN-1 alone.Ruisen Zhan Shijie Chen Weiguo Wang Haibin Long 2008Neural Regeneration Research2008,3,12:10
11Characteristics of ozone pollution and the sensitivity to precursors during early summer in central plain, China显示文摘In this study,we conducted an observation experiment from May 1 to June 30,2018 in Zhengzhou,a major city in central China,where ground ozone(O3)pollution has become serious in recent years.The concentrations of O3 and its precursors,as well as H2O_(2) and meteorological data were obtained from the urban site(Yanchang,YC),suburban(Zhengzhou University,ZZU)and background sites(Ganglishuiku,GLSK).Result showed that the rates of O3 concentration exceeded Chinese National Air Quality Standard GradeⅡ(93.3 ppbv)were 59.0%,52.5%,and 55.7%at the above three sites with good consistency,respectively,indicating that O3 pollution is a regional problem in Zhengzhou.The daily peak O3 appeared at 15:00-16:00,which was opposite to VOCs,NOx,and CO and consistent with H2O_(2).The exhaustive statistical analysis of meteorological factors and chemical effects on O3 formation at YC was advanced.The high concentration of precursors,high temperature,low relative humidity,and moderately high wind speed together with the wind direction dominated by south and southeast wind contribute to urban O3 episodes in Zhengzhou.O3 formation analysis showed that reactive alkenes such as isoprene and cis-2-butene contributed most to O3 formation.The VOCs/NOx ratio and smog production model were used to determine O3-VOC-NOx sensitivity.The O3 formation in Zhengzhou during early summer was mainly under VOC-limited and transition regions alternately,which implies that the simultaneous emission reduction of alkenes and NOx is effective in reducing O3 pollution in Zhengzhou.Yasong Li Shasha Yin Shijie YU Ling Bai Xudong Wang Xuan Lu Shuangliang Ma 2021Journal of Environmental Sciences2021,33,1:10
12Optically pumped terahertz sources显示文摘High-power terahertz(THz) generation in the frequency range of 0.1-10 THz has been a fast-developing research area ever since the beginning of the THz boom two decades ago, enabling new technological breakthroughs in spectroscopy, communication, imaging,etc. By using optical(laser) pumping methods with near-or mid-infrared(IR) lasers, flexible and practical THz sources covering the whole THz range can be realized to overcome the shortage of electronic THz sources and now they are playing important roles in THz science and technology. This paper overviews various optically pumped THz sources, including femtosecond laser based ultrafast broadband THz generation, monochromatic widely tunable THz generation, single-mode on-chip THz source from photomixing, and the traditional powerful THz gas lasers. Full descriptions from basic principles to the latest progress are presented and their advantages and disadvantages are discussed as well. It is expected that this review gives a comprehensive reference to researchers in this area and additionally helps newcomers to quickly gain understanding of optically pumped THz sources.ZHONG Kai SHI Wei XU DeGang LIU PengXiang WANG YuYe MEI JiaLin YAN Chao FU ShiJie YAO JianQuan 2017Science China(Technological Sciences)2017,60,12:9
13Microstructure, mechanical properties and deformation mechanisms of an as-cast Mg–Zn–Y–Nd–Zr alloy for stent applications显示文摘A new Mg-2Zn-0.2Y -0.5N d-0.4Zr (wt%) alloy designed specially for stent applications has been developed. The as-cast alloy is featured with equiaxed grains with a mean size of about 40 μm and a small am ount of second phase (T phase) distributed discontinuously either at the grain boundaries or inside the grains. This alloy exhibits a tensile elongation of up to 35%, which is much larger than that of most reported other as-cast Mg alloys. The tensile deform ation mechanisms have also been investigated. The results show that, besides basal slip,{10-12} extension twining and non-basal pyramidal slips can also be observed at initial stage and later stage during tensile deform ation, respectively, which are responsible for the good room -tem perature ductility.Jianfeng Wang Hongbo Zhou Liguo Wang Shijie Zhu Shaokang Guan 2019Journal of Materials Science & Technology2019,35,7:9
14Numerical study on the influence of initial ambient temperature on the aerodynamic heating in the tube train system显示文摘The evacuated tube transportation has great potential in the future because of its advantages of energy saving and environmental protection.The train runs in the closed tube at ultra-high speed.The heat quantity generated by aerodynamic heating is not easy to spread to external environment and then accumulates in the tube,inducing the ambient temperature in the tube to rise gradually.In this paper,a three-dimensional geometric model and the Shear Stress Transport(SST)κ-ωturbulence model are used to study the influence of initial ambient temperature on the structure of the flow field in the tube.Simulation results show that when the train runs at transonic speed,the supersonic flow region with low temperature and low-pressure is produced in the wake.The structure of the flow field of the wake will change with the initial ambient temperature.And the higher the initial ambient temperature is,the shorter the low temperature region in the wake will be.The larger temperature difference caused by the low temperature region may increase the temperature stress of the tube and affect the equipment inside the tube.Consequently,the temperature inside the tube can be maintained at a reasonable value to reduce the influence of the low temperature region in the wake on the system.Shijie Bao Xiao Hu Jukun Wang Tianhao Ma Yingyu Rao Zigang Deng 2020Advances in Aerodynamics2020,2,1:9
15Damage by wind-blown sand and its control measures along the Taklimakan Desert Highway in China显示文摘Desertification is one of the most serious environmental problems in the world,especially in the arid desert regions.Combating desertification,therefore,is an urgent task on a regional or even global scale.The Taklimakan Desert in China is the second largest mobile desert in the world and has been called the''Dead Sea''due to few organisms can exist in such a harsh environment.The Taklimakan Desert Highway,the longest desert highway(a total length of 446 km)across the mobile desert in the world,was built in the 1990s within the Taklimakan Desert.It has an important strategic significance regarding oil and gas resources exploration and plays a vital role in the socio-economic development of southern Xinjiang,China.However,wind-blow sand seriously damages the smoothness of the desert highway and,in this case,mechanical sand control system(including sand barrier fences and straw checkerboards)was used early in the life of the desert highway to protect the road.Unfortunately,more than 70%of the sand barrier fences and straw checkerboards have lost their functions,and the desert highway has often been buried and frequently blocked since 1999.To solve this problem,a long artificial shelterbelt with the length of 437 km was built along the desert highway since 2000.However,some potential problems still exist for the sustainable development of the desert highway,such as water shortage,strong sandstorms,extreme environmental characteristics and large maintenance costs.The study aims to provide an overview of the damages caused by wind-blown sand and the effects of sand control measures along the Taklimakan Desert Highway.Ultimately,we provide some suggestions for the biological sand control system to ensure the sustainable development of the Taklimakan Desert Highway,such as screening drought-resistant species to reduce the irrigation requirement and ensure the sound development of groundwater,screening halophytes to restore vegetation in the case of soil salinization,and planting cash crops,such as Cistanche,Wolfberry,Apocynum and other cash crops to decrease the high cost of maintenance on highways and shelterbelts.LI Congjuan WANG Yongdong LEI Jiaqiang XU Xinwen WANG Shijie FAN Jinglong LI Shengyu 2021Journal of Arid Land2021,13,1:9
16OsSPL18 controls grain weight and grain number in rice显示文摘Grain weight and grain number are two important traits directly determining grain yield in rice. To date,a lot of genes related to grain weight and grain number have been identified; however, the regulatory mechanism underlying these genes remains largely unknown. In this study, we studied the biological function of OsSPL18 during grain and panicle development in rice. Knockout (KO) mutants of OsSPL18exhibited reduced grain width and thickness, panicle length and grain number, but increased tiller number. Cytological analysis showed that OsSPL18 regulates the development of spikelet hulls by affecting cell proliferation. qRT-PCR and GUS staining analyses showed that OsSPL18 was highly expressed in developing young panicles and young spikelet hulls, in agreement with its function in regulating grain and panicle development. Transcriptional activation experiments indicated that OsSPL18is a functional transcription factor with activation domains in both the N-terminus and C-terminus, and both activation domains are indispensable for its biological functions. Quantitative expression analysis showed that DEP1, a major grain number regulator, was significantly down-regulated in OsSPL18 KO lines.Both yeast one-hybrid and dual-luciferase (LUC) assays showed that OsSPL18 could bind to the DEP1promoter, suggesting that OsSPL18 regulates panicle development by positively regulating the expression of DEP1. Sequence analysis showed that OsSPL18 contains the OsmiR156k complementary sequence in the third exon; 5?RLM-RACE experiments indicated that OsSPL18 could be cleaved by OsmiR156k. Taken together, our results uncovered a new OsmiR156k-OsSPL18-DEP1 pathway regulating grain number in rice.Hua Yuan Peng Qin Li Hu Shijie Zhan Shifu Wang Peng Gao Jing Li Mengya Jin Zhengyan Xu Qiang Gao Anping Du Bin Tu Weilan Chen Bingtian Ma Yuping Wang Shigui Li 2019Journal of Genetics and Genomics2019,46,1:8
17Research progresses of cathodic hydrogen evolution in advanced lead–acid batteries显示文摘Integrating high content carbon into the negative electrodes of advanced lead–acid batteries effectively eliminates the sulfation and improves the cycle life,but brings the problem of hydrogen evolution,which increases inner pressure and accelerates the water loss.In this review,the mechanism of hydrogen evolution reaction in advanced lead–acid batteries,including lead–carbon battery and ultrabattery,is briefly reviewed.The strategies on suppression hydrogen evolution via structure modifications of carbon materials and adding hydrogen evolution inhibitors are summarized as well.The review points out effective ways to inhibit hydrogen evolution and prolong the cycling life of advanced lead–acid battery,especially in high-rate partial-state-of-charge applications.Feng Wang Chen Hu Min Zhou Kangli Wang Jiali Lian Jie Yan Shijie Cheng Kai Jiang 2016Science Bulletin2016,61,6:8
18Combined effects of cadmium and fluoranthene on germination, growth and photosynthesis of soybean seedlings显示文摘The single and combinational effects of cadmium (Cd) and fluoranthene (FLT) on germination, growth and photosynthesis of soybean seedlings were investigated. Exposure to 5, 10, or 15 mg Cd/L or 1, 5, or 10 mg FLT/L individually or in combination significantly decreased germination vigor (3 days) and final germination rate of soybean seeds, except at 1 and 5 mg FLT/L. The results of two-way ANOVA analysis and the Bliss independence model showed that at lower concentrations of FLT (1 mg/L), the interaction between Cd and FLT on germination was antagonistic, whereas the interaction was synergistic when the concentration of FLT was 5 or 10 mg/L and the concentration of Cd was 15 mg/L. Growth, expressed as dry weight, length of shoot and root, leaf area, and photosynthesis, expressed as net photosynthetic rate, intercellular CO2 concentration, chlorophyll contents and fluorescence of soybean seedlings were also reduced by exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L, singly or jointly. Significant antagonistic effects of exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L on shoot growth and photosynthesis were observed, whereas synergy and antagonism of Cd and FLT were both observed for root growth.Qiushuang Li Yonglong Lu Yajuan Shi Tieyu Wang Kun Ni Li Xu Shijie Liu Lin Wang Qinli Xiong John.P Giesy 2013Journal of Environmental Sciences2013,25,9:8
19Enrichment of heavy metal elements and their adsorption on iron oxides during carbonate rock weathering process显示文摘Analysis of trace elements in the Lower Palaeozoic carbonate rock strata of the Beijing area shows that the Cr, Zn, Cd and Pb contents increase from primary carbonate rocks to weathered carbonate rocks and from primary carbonate rocks to the soil coexisting with carbonate rock. Distributions of Cr, Zn, Cd and Pb have the same trends as that of Fe2O3. Iron oxides play different roles at different stages of weathering of carbonate rock. The adsorption of Cr, Zn, Cd and Pb on Fe2O3 is greater than on FeO in soil. However, FeO, as a main component of clay mineral, is a better adsorbent of Cr, Zn, Cd and Pb than Fe2O3 in weathered and primary carbonate rocks. According to R-type clustering analysis, the main components of carbonate rock are divided into marine and continental sediments. Correlation analysis shows that heavy metal elements mainly exist in continental substances.Shanqin Ni Yiwen Ju Quanlin Hou Shijie Wang Qing Liu Yudong Wu Lingling Xiao 2009Progress in Natural Science:Materials International2009,19,9:8
20Characteristics of strontium isotopes and their implications in the Qixing Cave of Guizhou, China显示文摘The strontium isotopic compositions (87Sr/86Sr) of samples including soils, bedrock, soil waters, drip waters and their corresponding speleothems in the Qixing Cave (QXC), Guizhou Province, China, were systemically measured and analyzed. The results indicate that there are significant Sr isotopic differences among samples. The mean 87Sr/86Sr ratios in drip water for the samples 1#, 4# and 9# were 0.709568, 0.709139 and 0.708761, respectively, which possibly result from different flow paths, residence times, and other hydrogeological processes in the unsaturated zone overlying QXC. Meanwhile, levels of 40.8%, 57.6% and 72.4% of Sr in drip waters for 1#, 4# and 9#, respectively, were derived from bedrock dissolution, which was calculated by the mixture model of the two end-members (soil and bedrock). There is, however, no positive correlation between the relative proportion from bedrock dissolution (δ13C value is 1.8‰) and drip water δ13CDIC values. The mean drip water δ13CDIC value in 1# is the heaviest (–4.5‰) with the lowest contribution rate of bedrock dissolution, whereas the value in 9# is the lightest (–9.3‰) with the highest contribution rate of bedrock dissolution. The proportion from host rock dissolution in 4# is higher than that in 1# and lower than that in 9#, while its mean drip water δ13CDIC value (–8.6‰) is higher than that of 9# and lower than that for 1#. This suggests that the prior calcite precipitation (PCP) processes in the unsaturated zone overlying the cave are responsible for the δ13CDIC value differences between different drip waters, and not bedrock dissolution. Furthermore, this study also demonstrates that the 87Sr/86Sr ratios of speleothems in the 1# and 4# mainly reflect the variation in the relative proportions from the soil system (soil water) and bedrock dissolution overlying the cave. It is, therefore, feasible to use the strontium isotopic signals of speleothems as an indicator for soil chemical weathering intensity, and consequently as a monsoon proxy in the study area.ZHU XiaoLong WANG ShiJie LUO WeiJun 2011Chinese Science Bulletin2011,56,7:8
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