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| 1 | 西秦岭与埃达克岩和喜马拉雅型花岗岩有关的金铜成矿及找矿问题显示文摘秦岭金矿分布广,目前学术界大多认为分属于造山型和卡林型金矿两类。该区印支期花岗岩发育,大多具有埃达克岩和喜马拉雅型花岗岩(低Sr和Yb)的特点,与金铜矿在时空分布上相关。美国内华达州卡林型金矿是世界级的金矿聚集区,与卡林型金矿有关的第三纪岩浆岩(中酸性火山岩和浅成花岗岩)也具有埃达克岩和喜马拉雅型花岗岩的地球化学特征,暗示内华达卡林型金矿也来源于加厚下地壳的底部。本文讨论了埃达克岩和喜马拉雅型花岗岩有利于成矿的机理,并根据西秦岭金矿与花岗岩分布的关系,提出以夏河-宕昌-两当-凤县为界将西秦岭划分为南北两个成矿区和13个成矿聚集区:北区花岗岩发育,有利于寻找斑岩型、夕卡岩型等热液型金铜矿床;南带侵入岩少而小,有利于寻找远离岩体的金矿(包括卡林型等)。鉴于西秦岭印支期埃达克岩和喜马拉雅型花岗岩发育,金铜尤其是金矿分布多,储量大,且大多与埃达克岩或喜马拉雅型花岗岩有关,可能是中国金矿最具潜力的地区,有利于特大型金铜矿的产出,可能发展成为中国最大的金矿聚集区。为此,建议加强本区花岗岩与金铜成矿关系的研究,革新找矿思路和找矿技术方法,以实现找矿的新突破。 | 张旗 殷先明 殷勇 金惟俊 王元龙 赵彦庆 | 2009 | 岩石学报2009，25，12： | 69 |
| 2 | GPS-constrained inversion of present-day slip rates along major faults of the Sichuan-Yunnan region, China显示文摘A linked-fault-element model is employed to invert for contemporary slip rates along major active faults in the Sichuan-Yunnan region (96°-108°E, 21°-35°N) using the least squares method. The model is based on known fault geometry, and constrained by a GPS-derived horizontal velocity field. Our results support a model attributing the eastward extrusion of the Tibetan Plateau driven mainly by the north-northeastward indentation of the Indian plate into Tibet and the gravitational collapse of the plateau. Resisted by a relatively stable south China block, materials of the Sichuan-Yunnan region rotate clockwise around the eastern Himalayan tectonic syntaxis. During the process the Garzê-Yushu, Xianshuihe, Anninghe, Zemuhe, Daliangshan, and Xiaojiang faults, the southwest extension of the Xiaojiang fault, and the Daluo-Jinghong and Mae Chan faults constitute the northeast and east boundaries of the eastward extrusion, with their left slip rates being 0.3-14.7, 8.9-17.1, 5.1 ± 2.5, 2.8 ± 2.3, 7.1 ± 2.1, 9.4 ± 1.2, 10.1 ± 2.0, 7.3 ± 2.6, and 4.9 ± 3.0 mm/a respectively. The southwestern boundary consists of a widely distributed dextral transpressional zone other than a single fault. Right slip rates of 4.2 ± 1.3, 4.3 ± 1.1, and 8.5 ± 1.7 mm/a are detected across the Nanhua-Chuxiong-Jianshui, Wuliangshan, and Longling-Lancang faults. Crustal deformation across the Longmenshan fault is weak, with short-ening rates of 1.4 ± 1.0 and 1.6 ± 1.3 mm/a across the Baoxing-Beichuan and Beichuan-Qingchuan segments. Northwest of the Longmenshan fault lies an active deformation zone (the Longriba fault) with 5.1±1.2 mm/a right slip across. Relatively large slip rates are detected across a few faults within the Sichuan-Yunnan block: 4.4±1.3 mm/a left slip and 2.7±1.1 mm/a shortening across the Litang fault, and 2.7±2.3 mm/a right-lateral shearing and 6.7±2.3 mm/a shortening across the Yunongxi fault and its surrounding regions. In conclusion, we find that the Sichuan-Yunnan region is divided into more than a dozen active micro-blocks by a large number of faults with relatively slow slip rates. The eastward extrusion of the Tibetan Plateau is absorbed and adjusted in the region mainly by these faults, other than a small number of large strike-slip faults with fast slip rates. | WANG YanZhao WANG EnNing SHEN ZhengKang WANG Min GAN WeiJun QIAO XueJun MENG GuoJie LI TieMing TAO Wei YANG YongLin CHENG Jia LI Peng | 2008 | Science China Earth Sciences2008，51，9： | 65 |
| 3 | Analysis and design for the second order nonlinear continuous extended states observer显示文摘The extended state observer (ESO) is a novel observer for a class of uncertain systems. Since ESO adopts the continuous non-smooth structure, the classical observer design theory is hard to use for ESO analysis. In this note, the self-stable region (SSR) approach, which is a nonlinear synthesis method for nonlinear uncertain systems, will be used for ESO design and its stability analysis. The advantages of the non-smooth structure in ESO for improving the convergence properties and the estimation precision will be shown. | Yi Huang Jingqing Han | 2000 | Chinese Science Bulletin2000，45，21： | 65 |
| 4 | 贺兰山孔兹岩系的变质时代及其对华北克拉通西部陆块演化的制约显示文摘贺兰山孔兹岩系作为华北克拉通西部孔兹岩带的重要组成部分,其变质时代问题一直悬而未决。利用SHRIMP锆石U-Pb定年技术,对贺兰山孔兹岩系中3个代表性富铝片麻岩(石榴堇青钾长片麻岩、石榴堇青二长片麻岩与石榴黑云斜长片麻岩)样品进行了精确定年。发现这3种岩石虽处不同层位,但其碎屑锆石年龄却非常集中,各测点^(207)Pb/^(206)Pb年龄总体变化在2.0~2.1Ga之间,加权平均年龄则在2017~2040Ma之间。这些碎屑锆石都具有岩浆结构特征,反映当时曾存在大规模花岗质岩浆活动,所成岩体为孔兹岩系沉积提供了充足物源。另有少量大于2.5Ga的碎屑锆石(2520~2949Ma),表明本区存在太古代岩浆活动记录。本区石榴堇青二长片麻岩中发育典型的变质增生锆石,其成因很可能与黑云母的脱水熔融反应有关。利用该锆石确定贺兰山孔兹岩系的变质时代为1950±8Ma。该时代与东部大青山、乌拉山孔兹岩系变质时代相同,表明华北克拉通西部的阴山地块与鄂尔多斯地块大体是以平行的方式正面拼贴到一起的。 | 周喜文 耿元生 | 2009 | 岩石学报2009，25，8： | 55 |
| 5 | Amplitude of climatic changes in Qinghai-Tibetan Plateau显示文摘On the basis of ice core and meteorological data from the Qinghai-Tibetan (Q-l) Plateau, this article focuses on the discussion of the problems related to the sensitivity of temporal and spatial changes of the climate in high-altitude regions, particularly in the Q-T Plateau. The features of abrupt climatic changes of the past 100 ka, 2 000 a and recent years indicate that the amplitude of these changes in the Q-T Plateau was obviously larger than that in low-altitude regions. The scope of temperature change above 6 000 m in the Q-T Plateau between glacial and interglacial stages could reach over 10C℃, but only about 4℃ in low-elevation regions close to sea level. During the last 2 000 a, the amplitude of temperature changes at Guliya (over 6 000 m a.s.l.) in the Q-T Plateau reached 7℃, in comparison with 2℃ in eastern China at low altitude. In the present age, apparent differences of climatic warming have been observed in the Q-T Plateau, indicating that the warming in high-elevation regions is | YAO Tandong LIU Xiaodong WANG Ninglian SHI Yafeng | 2000 | Chinese Science Bulletin2000，45，13： | 47 |
| 6 | Discovery of eclogite inclusions and its geological significance in early Jurassic intrusive complex in Xuzhou-northern Anhui, eastern China显示文摘The early Jurassic intrusive complex is chiefly made of monzodioritic porphyry in northern Anhui and northern Jiangsu, which emplaced in 191 Ma. The intrusive complexes contain a lot of eclogite inclusions which belong to eclogite and garnet-pyroxenite. The inclusions had undergone eclogite facies high-pressure metamorphism and am-phibolite facies retrogressive metamorphism. The garnets in eclogite inclusions are mainly almandine varieties and clino-pyroxenes are omphacite and augite. The mineral assemblage and P-T estimation results show that P-T conditions of eclogite facies metamorphism and amphibolite facies retrogressive metamorphism are over 1.2-1.5 GPa, 709-861°C and 0.7-1.03 GPa, 666-738°C, respectively. The discovery of the high-pressure xenoliths not only is of important significance to understand the composition and structure of deep crust in southern edge of North China Platform, but also can be of important influence on realizing the subduc-tion-collision-exhumation evolutional process | Wenliang Xu Dongyan Wang Xiaochun Liu Qinghai Wang Jingqian Lin | 2002 | Chinese Science Bulletin2002，47，14： | 37 |
| 7 | New evidence for the Qinghai-Xizang (Tibet) Plateau as a pilot region of climatic fluctuation in China显示文摘Over 40 a observed temperature data in 172 stations in China and historical proxy data were analyzed. Evidence suggested that during 1980-1994, the warmest year appeared first in southeastern part of the Qinghai_Xizang (Tibet) Plateau (henceforth SETP) and then gradually spread northwards and eastwards to eastern China. The climatic change on century time scale in recent 600 a shows 3 relatively warm and clod stages in China. Each warm and cold stage appeared first in Tibet Plateau (henceforth TP) and then in the Qilian Mountains, then in the eastern parts of China. The warm and cold stages in TP were 10-60 a earlier than in the eastern China. The facts show that TP is a pilot region of climatic fluctuation in China on the time scale shorter than 10\+3a. | Song Feng Maocang Tang Dongmei Wang | 1998 | Chinese Science Bulletin1998，43，20： | 35 |
| 8 | Climate change tendency and grassland vegetation response during the growth season in Three-River Source Region显示文摘Climate change,climate suitablity change for grassland vegetation,and grassland response to climate change during the growth season are studied systematically by using meteorological data of temperature,precipitation,and length of sunlight from 1961 to 2007,NOAA/AVHRR NDVI from 1982 to 2006,and observations of grass height,biomass,and coverage in enclosed grassland from 1994 to 2006.Two models are developed to evaluate climate change and the climatic suitability of grassland vegetation growth.Average temperature,accumulative precipitation,and length of sunlight during the growth season increased from 1961 to 2007 at rates of 0.24°C/10 yr,2.32 mm/10 yr,and 2.81 h/10 yr,respectively.The increase rates of ave-rage temperature between April and May,and between June and August are 0.17 and 0.30°C/10 yr;accumulative rainfall between April and May increased at a rate of 2.80 mm/10 yr,and accumulative rainfall between June and August decreased at a rate of 0.38 mm/10 yr;the increase rates of accumulative length of sunlight between April and May,and between June and August are 2.15 and 1.2 h/10 yr.The climatic suitability of grassland vegetation growth showed an increasing trend,and the increase rate between April and May is greater than that between June and August.Both NDVI observations from 1982 to 2006 and measurements of grass height,dry biomass,and coverage from 1994 to 2006 show that the climate change has resulted in an increase in plant productivity of the grassland in Three-River Source Region.If some protection measures are taken as soon as possible,the deteriorated grassland in Three-River Source Region can recover. | QIAN Shuan1,FU Yang2 & PAN FeiFei3 1 National Meteorological Center,Beijing 100081,China 2 Qinghai Meteorological Research Institute,Xining 810001,China 3 Department of Geography,University of North Texas,Denton,TX 76203,USA | 2010 | Science China Earth Sciences2010，53，10： | 25 |
| 9 | CURVILINEAR PATHS AND TRUST REGION METHODS WITH NONMONOTONIC BACK TRACKING TECHNIQUE FOR UNCONSTRAINED OPTIMIZATION显示文摘In this paper we modify type approximate trust region methods via two curvilinear paths for unconstrained optimization. A mired strategy using both trust region and line search techniques is adopted which switches to back tracking steps when a trial step produced by the trust region subproblem is unacceptable. We give a series of properties of both optimal path and modified gradient path. The global convergence and fast local convergence rate of the proposed algorithms are established under some reasonable conditions. A nonmonotonic criterion is used to speed up the convergence progress in some ill-conditioned cases. | De-tong Zhu (Department of Mathematics, Shanghai Normal University, Shanghai 200234, China) | 2001 | Journal of Computational Mathematics2001，19，3： | 26 |
| 10 | THE CHARACTERS OF ENERGY BUDGET ON THE GOBI AND DESERT SURFACE IN HEXI REGION显示文摘In the paper,the characters of surface energy budget on Huayin(Gobi)and the desert surface during the periodfrom 26 June to 31 August 1990 in the HEIFE have been analyzed,then have been compared with the observed resultsduring 4—19 September 1988 in the Pilot Observation Period of the HEIFE.The results show that the atmosphere is insuperadiabatic unstable state and there is a phenomenon of inverse humidity to form negative water vapour flux.Thesensible heat flux on the surface energy budget is in majority,but the latent heat flux may be neglected over the Gobi anddesert surface in the cloudless daytime in the summer. | 胡隐樵 杨选利 张强 左洪超 | 1992 | Acta meteorologica Sinica1992，6，1： | 23 |
| 11 | 长三角整合及其未来发展趋势--20年长三角地区边界、重心与结构的变化显示文摘立足于三大核心观点:①区域联盟发展决定了各个城市在全球化浪潮中的发展前景:②全球化的世界中各个城市的世界地位取决于城市区域的发展基础:③只有通过区域和谐联动才有单个城市的科学发展。通过对长三角城市群规模和等级结构与功能与空间结构的定量解读,特别是对长三角城市群边界、重心、结构的20年演变分析,得出'长三角空间结构的演变特征与趋势都体现出一种行政区经济影响在空间结构上的反映'的基本判断:继而展开对长三角一体化进程的事件性统计分析,并指出2010上海世博会应成为推动长三角一体化发展的首要因素:最后提出从行政经济走向城市群经济,是长三角发展的破题之作,也是区域未来实现新一轮发展的核心诉求,联盟、创新与转型将成为长三角城市群未来成长为Global Region的关键。 | 吴志强 王伟 李红卫 于涛方 王雷 | 2008 | 城市规划学刊2008，，2： | 22 |
| 12 | Monitoring lake changes of Qinghai-Tibetan Plateau over the past 30 years using satellite remote sensing data显示文摘During the years 2006–2009,lakes in the Qinghai-Tibetan Plateau(QTP)were investigated using satellite remote sensing strategies.We report the results of this investigation as well as follow-up research and expanded work.For the investigation,we mainly focused on lakes whose areas are more than 1 km2.The remote sensing data that we used included 408 scenes of CBERS CCD images and 5 scenes of Landsat ETM?images in Qinghai Province and Tibet Autonomous Region.All these data were acquired around years 2005–2006.Besides remote sensing images,we also collected 1,259 topographic maps.Numbers and areas of lakes were analyzed statistically,which were then compared with those coming from the first lake investigation(implemented between the1960s and 1980s).According to our investigation,up to and around year 2005–2006,the total number of lakes in the QTP was 1,055(222 in Qinghai and 833 in Tibet),accounting for more than 30%of that of China.Thirty newborn lakes with area[1 km2were found,and 5 dead lakes with initial area[1 km2were also found.Among those 13 big lakes([500 km2),Yamzhog Yumco had seriously shrunk,and it has continued to shrink in recent years;Qinghai Lake had shrunk during the period,but some new researches indicated that it has been expanding since the year 2004;Siling Co,Nam Co,and Chibuzhang Co had expanded in the period.We divided the newborn lakes into six categories according to their forming reasons,including river expansion,wetland conversion,etc.The changes of natural conditions led to the death of four lakes,and human exploitation was the main reason for the death of Dalianhai Lake in Qinghai.We picked out three regions which were sensitive to the change of climate and ecological environment:Nagqu Region,Kekexili Region,and the source area of the Yellow River(SAYR).Lakes in both Nagqu and Kekexili have been expanded;meanwhile,most lakes in the SAYR have obviously been shrunk.These regional patterns of lake changes were highly related to variations of temperature,glacier,precipitation,and evaporation.Our investigation and analysis will provide references for researches related to lake changes in the QTP and the response to climate fluctuations. | Wei Wan Pengfeng Xiao Xuezhi Feng Hui Li Ronghua Ma Hongtao Duan Limin Zhao | 2014 | Chinese Science Bulletin2014，59，10： | 22 |
| 13 | p16 gene methylation in colorectal cancers associated with Duke's staging显示文摘AIM To explore the association of methylation of the CpG island in the promotor of the p16 tumor suppressor gene with the clinicopathological characteristics of the colorectal cancers.``METHODS Methylation-specific PCR (MSP) was used to detect p16 methylation of 62 sporadic colorectal cancer specimens.``RESULTS pi6 methylation was detected in 42% of the tumors. Dukes staging was associated with p16methylation status, p16 methylation occurred more frequently in Dukes C and D patients (75.9%) than in Dukes A and B patients (12.1%).``CONCLUSION p16 rnethylation plays a role in the carcinogenesis of a subset of colorectal cancer, and it might be linked to poor prognosis. | Jing Yi~1 Zhi-Wei Wang~1 Hui Cang~1 Yu-Ying Chen~1 Ren Zhao~2 Bao-Ming Yu~2 Xue-Ming Tang~1 1 Department of Cell Biology,2 Department of Surgery,Ruijin Hospital,Shanghai Second Medical University,Shanghai 200025,China | 2001 | World Journal of Gastroenterology2001，7，5： | 21 |
| 14 | 新疆西南天山木扎尔特河一带低压泥质麻粒岩岩石学特征、独居石U-Th-Pb定年及其地质意义显示文摘古南天山洋闭合过程中,由于洋壳俯冲产生的岛弧岩浆作用加热大陆地壳,在新疆西南天山木扎尔特一带形成了一套低压高温泥质麻粒岩相变质岩石。本文用Theriak-Domino热力学软件对该套岩石中的堇青石榴夕线石黑云母片麻岩和含夕线石堇青石榴黑云母片麻岩进行了岩石学相平衡计算研究,得到它们峰期变质的温压条件分别是:T=630~674℃,P=5.2~5.5kbar和T=645~684℃,P=5.4~5.7kbar。并采用独居石Th-U-Pb电子探针定年方法,对样品WQ006中的3颗独居石进行了原位年龄测定(38个分析点),得到2组等时线年龄,分别是376±8Ma和280±8Ma(2σ)。结合独居石的岩相学特征,提出了新疆西南天山低压高温麻粒岩相峰期变质作用的时代为280±8Ma,而376±8Ma(2σ)可能为原沉积岩的原岩/成岩年龄。表明西南天山洋壳开始俯冲发生在晚古生代,进一步证明了西南天山造山带俯冲碰撞发生在晚二叠纪之后的观点。 | 苟龙龙 张立飞 G0U | 2009 | 岩石学报2009，25，9： | 21 |
| 15 | 海南省五指山地区油茶林调查研究显示文摘油茶是我国南方特有的重要木本油料树种之一,有很大的发展潜力。本文对海南省五指山地区油茶林进行了定点调查,分析了油茶的产量、营养状况以及不同区域的差异性。结果表明,五指山地区不同区域之间,油茶林的产量存在高、中、低三种状况,油茶营养元素含量呈显著性差异。这将为五指山地区油茶林的科学管理以及进一步发展提供一定的参考依据。 | 李艳 陈良秋 杨伟波 唐龙祥 郑亚军 孙丽萍 | 2010 | 江西农业学报2010，22，11： | 20 |
| 16 | Construction of infectious cDNA clones of PRRSV:Separation of coding regions for nonstructural and structural proteins显示文摘Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), the causative agent of the ongoing 'porcine high fever syndrome' in China, is capable of genetic and antigenic mutations at high fre- quency. How to design vaccine rationally to keep up with the ever-changing prevalent PRRSV variant is of great interest. We developed an infectious cDNA clone of an attenuated strain of Type II PRRSV, and further manipulated the infectious cDNA clone by inserting polylinker between ORF1 and ORF2, en- coding for nonstructural- or structural-protein, respectively. The cDNA was generated from the cell-attenuated virus strain, APRRS, via RT-PCR, and followed by nucleotide sequencing and molecular cloning. The full-length of the APRRS genomic RNA was determined as 15521 nucleotides in length excluding poly(A) tail, which has a 99.7% nucleotide identity with that of PRRSV Nsp strain, also a vac- cine strain. Based on the nucleotide sequencing results, the full-length cDNA clone was assembled in pBlueScript vector, under the control of T7 promoter at the immediate 5′ terminus of genome. To dis- cern the rescued viruses from that of parental virus, a Mlu I restriction site was engineered into ORF5 coding region. Upon transfection of the in vitro transcripts of both the original and Mlu I-tagged cDNAs into MA-104 cells, typical PRRSV cytopathic effects were observed. The rescued viruses from the full-length cDNA clones displayed the same virological and molecular properties. Subsequently, PCR-based mutagenesis was conducted to separate the coding regions between PRRSV nonstructural genes, ORF1, and structural proteins, ORF2-ORF7. The synthetic RNA of such mutant clone, pCSA, was infectious and the rescued virus shared similar properties with that of the parental virus. This study provided a valuable tool for development of chimeric PRRSV as vaccine candidate offering cross-protection to various genetically diversified PRRSV strains, and a platform for further develop- ment of PRRSV as a gene expression vector for recombinant vaccines against other significant swine diseases. | YUAN ShiShan & WEI ZuZhang Department of Animal Infectious Diseases, Key Laboratory of Animal Parasitology Chinese Ministry of Agriculture, Shanghai Vet- erinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200232, China | 2008 | Science China(Life Sciences)2008，51，3： | 19 |
| 17 | Finite difference method and analysis for three-dimensional semiconductor device of heat conduction显示文摘The mathematical model of the three-dimensional semiconductor devices of heat conduction is described by a system of four quasilinear partial differential equations for initial boundary value problem. One equation in elliptic form is for the electric potential; two equations of convection-dominated diffusion type are for the electron and hole concentration; and one heat conduction equation is for temperature. Characteristic finite difference schemes for two kinds of boundary value problems are put forward. By using the thick and thin grids to form a complete set and treating the product threefold-quadratic interpolation, variable time step method with the boundary condition, calculus of variations and the theory of prior estimates and techniques, the optimal error estimates in L2 norm are derived in the approximate solutions. | 袁益让 | 1996 | Science China Mathematics1996，39，11： | 19 |
| 18 | Petrogenesis and its significance to continental dynamics of the Neogene high-potassium calc-alkaline volcanic rock association from north Qiangtang,Tibetan Plateau显示文摘Detailed studies indicate that the main rock type of the Neogene high-potassium calc-alkaline volcanic rock association from north Qiangtang is andesite, dacite and rhyolite. They belong to typical crust-generation magmatic system and originate from the special thickened crust of the Tibetan Plateau by dehydration melting. This group of rocks exhibits LREE enrichment but no remarkable Eu anomaly that shows their source region should be a thickened deep crust consisting of eclogitic mass group, implying that the crust had been thickened and an eclogitic deep crust had been formed during the Neogene period in Qiangtang area. This understanding is important and significant to making further discussion on the uplift mechanism and continental dynamics of the Tibetan Plateau. | 赖绍聪 刘池阳 S.Y.O’Reilly | 2001 | Science China Earth Sciences2001，44，S1： | 18 |
| 19 | Regional stress field in Yunnan revealed by the focal mechanisms of moderate and small earthquakes显示文摘We determined focal mechanism solutions of 627 earthquakes of magnitude M ≥ 3.0 in Yunnan from January 2008 to May 2018 by using broadband waveforms recorded by 287 permanent and temporary regional stations. The results clearly revealed predominantly strike-slip faulting characteristics for earthquakes in Yunnan, with focal depths concentrated in the top 10 km of the crust. The earthquake mechanisms obtained were combined with the global centroid moment tensor solutions of 80 additional earthquakes from 1976 to 2016 to invert for the regional variations of stress field orientation by using a damped regional-scale stress inversion scheme.Results of the stress field inversion confirmed that the Yunnan region is under a strike–slip stress regime, with both maximum and minimum stress axes being nearly horizontal. The maximum compressional axes are primarily oriented in a northwest-southeast direction, and they experience a clockwise rotation from north to south, whereas the maximum extensional axes are oriented largely northeast-southwest. The maximum compressional axes are in line with the global positioning system–inferred horizontal velocity field and the southeastward escape of the Sichuan–Yunnan Rhombic Block, whereas the maximum extensional axes are consistent with anisotropy derived from SKS splitting. Against the strike–slip background, normal faulting stress regimes can be seen in the Tengchong volcanic area as well as in other areas with complex crisscrossing fault zones. | JianHui Tian Yan Luo Li Zhao | 2019 | Earth and Planetary Physics2019，3，3： | 16 |
| 20 | Critical slope gradient for compulsory abandonment of farmland on the hilly Loess Plateau显示文摘Scientific evidence for the upper limit of farmland is proposed. Shallow gully erosion is one of erosion types distributed extensively on sloping farmland in the hilly regions of the Loess Plateau. Field observation and aerial photos interpretation, as well as laboratory experiments show that the shallow gully erosion occurring on the steeper farmland in the hilly regions of the Loess Plateau is an important factor leading to intensive erosion on slope, because of its extensive distribution and intensive runoff collection. The data on the formation, development and distribution of shallow gullies on sloping farmland indicate that critical slope gradient for shallow gully initiation ranges from 15 to 20 degrees with an average of 18.2 degrees. Therefore, it is suggested that critical slope gradient for compulsory abandonment of farmland on the hilly Loess Plateau should be kept within the critical slope gradient for shallow gully initiation to prevent shallow gully formation in order to control soil loss more effectively. But as the first step, the cultivation on the slopes with slope larger than 25 degrees where the maximum erosion occurs should be strictly forbidden. | TANG Keli+1, ZHANG Keli 1,2 and LEI Aling 1,3 1. Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling 712100, China 2. Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China 3. Water Resources C | 1998 | Chinese Science Bulletin1998，43，5： | 16 |
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