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| 1 | Reconstruction of precipitation variation from tree rings in recent 1000 years in Delingha, Qinghai显示文摘Using seven well-replicated Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies developed at Zongwulong and Shalike Mts. in the northeastern part of the Qaidam Basin annual precipitation from previous July to current June in the recent 1000 years was re- constructed for Delingha. The reconstruction can capture 63.1% of precipitation variance and the equation was stable over time. For the reconstructed precipitation, wet periods occurred in AD1520—1633 and 1933—2001, whereas dry intervals in 1429—1519 and 1634—1741. In ad- dition, the magnitude in precipitation variation was lower before 1430 with about 15 mm, but it increased to 30 mm during the period of 1430 to 1850. After 1850, the precipitation variance de- creased again. In contrast to the increase in temperature, a decrease in annual precipitation was evident since the 1990s. The agreement in low-frequency variation between the reconstruction and the glacier accumulation and particulate content in Dunde ice cores during the recent several hundred years suggested that the precipitation reconstructed in this study was rather reliable, and represented a regional signal. This 1000-year reconstruction could benefit our understanding of climatic variation in decadal to century-scale in this region, and provide basic data to climate models and to prediction of future climate in the 21st century. | SHAO Xuemei1, HUANG Lei1, LIU Hongbin2, LIANG Eryuan1, FANG Xiuqi3 & WANG Lili1 1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2. National Climate Center, Beijing 100081, China 3. Beijing Normal University, Beijing 100875, China | 2005 | Science China Earth Sciences2005，48，7： | 113 |
| 2 | The land use and land cover change database and its relative studies in China显示文摘In the mid-1990s, we established the national operative dynamic information serving systems on natural resources and environment. During building the land-use/land-cover change (LUCC)database for the mid-1990s, 520 scenes of remotely sensed images of Landsat Thematic Mapper (TM) were interpreted into land-use/land-cover categories at scale of 1:100,000 under overall digital software environment after being geo-referenced and ortho-rectified. The vector map of land-use/land-cover in China at the scale of 1:100,000 was recently converted into a 1-km raster database that captures all ofthe high-resolution land-use information by calculating area percentage for each kind of land use category within every cell. Being designed as an operative dynamic information serving system,monitoring the change in land-use/land-cover at national level was executed. We have completed the updating of LUCC database by comparing the TM data in the mid-1990s with new data sources received during 1999-2000 and 1989-1990. The LUCC database has supported greatly the national LUCC research program in China and some relative studies are incompletely reviewed in this paper. | LIU Jiyuan, LIU Mingliang, DENG Xiangzheng, ZhuangDafang,ZHANG Zengxiang, LUO Di(1. Inst. of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China 2. Inst. of Remote Sensing Applications, CAS, Beijing 100101, China) | 2002 | Journal of Geographical Sciences2002，12，3： | 96 |
| 3 | Spatiotemporal variations of vegetation cover on the Chinese Loess Plateau(1981―2006):Impacts of climate changes and human activities显示文摘Spatiotemporal variations of Chinese Loess Plateau vegetation cover during 1981-2006 have been investigated using GIMMS and SPOT VGT NDVI data and the cause of vegetation cover changes has been analyzed, considering the climate changes and human activities. Vegetation cover changes on the Loess Plateau have experienced four stages as follows: (1) vegetation cover showed a continued increasing phase during 1981―1989; (2) vegetation cover changes came into a relative steady phase with small fluctuations during 1990―1998; (3) vegetation cover declined rapidly during 1999―2001; and (4) vegetation cover increased rapidly during 2002―2006. The vegetation cover changes of the Loess Plateau show a notable spatial difference. The vegetation cover has obviously increased in the Inner Mongolia and Ningxia plain along the Yellow River and the ecological rehabilitated region of Ordos Plateau, however the vegetation cover evidently decreased in the hilly and gully areas of Loess Plateau, Liupan Mountains region and the northern hillside of Qinling Mountains. The response of NDVI to climate changes varied with different vegetation types. NDVI of sandy land vegetation, grassland and cultivated land show a significant increasing trend, but forest shows a decreasing trend. The results obtained in this study show that the spatiotemporal variations of vegetation cover are the outcome of climate changes and human activities. Temperature is a control factor of the seasonal change of vegetation growth. The increased temperature makes soil drier and unfavors vegetation growth in summer, but it favors vegetation growth in spring and autumn because of a longer growing period. There is a significant correlation between vegetation cover and precipitation and thus, the change in precipitation is an important factor for vegetation variation. The improved agricultural production has resulted in an increase of NDVI in the farmland, and the implementation of large-scale vegetation construction has led to some beneficial effect in ecology. | XIN ZhongBao1,2, XU JiongXin1 & ZHENG Wei1, 2 1 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2 Graduate University of the Chinese Academy of Sciences, Beijing 100049, China | 2008 | Science China Earth Sciences2008，51，1： | 112 |
| 4 | Temperature variations recovered from tree-rings in the middle Qilian Mountain over the last millennium显示文摘Based on the cross-dated tree-ring samples collected from the middle Qilian Moun- tain, a standard ring-width chronology had been developed, which covered the period AD 1000 to 2000. The correlations between the chronology and climatic records from the nearby meteorological stations indicated that temperature was the dominant climatic factor for tree growth at upper timberline, and the most important climatic factor for the tree growth in the area was the mean temperature from previous December to current April. The temperature variations recovered from the ring-width data showed a cold period during the “Little Ice Age” and the con- tinuous warming during the twentieth century. Comparison between the ring-width chronology and δ18O records from the Dunde ice core in the Qilian Mountain indicated that there was a con- sistent trend in both time series. A significant correlation existed between our ring-width chro- nology and the Northern Hemispheric temperature, suggesting that the climate changes in the Qilian Mountain were not only driven by regional factors, but also responsive to the global cli- mate. | LIU Xiaohong1,2, QIN Dahe1, SHAO Xuemei , CHEN Tuo1 & REN Jiawen12 1. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China 2. Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China | 2005 | Science China Earth Sciences2005，48，4： | 66 |
| 5 | Fluxes of CO_2, N_2O and CH_4 from a typical temperate grassland in Inner Mongolia and its daily variation显示文摘Using a dark enclosed chamber technique, the fluxes of CO2, N2O and CH4 from nature and disturbed grassland were measured on the spot in Inner Mongolian Temperate Grassland along the annual rainfall gradient section ranging from 450 to 200 mm. The results showed that the measured mean fluxes of CO2, N2O and CH4were (1 180.4 ±308.7), (0.010 ± 0.004) and (-0.039 ± 0.016) mg · m-2/h, respectively. The decrease of the fluxes of CO2, N2O and CH4 follows with that of annual rainfall gradient in the measurement area. Human activities, such as grazing and reclamation are also critical factors to affect the fluxes of these gases from grassland. Daily continuous measurement of CO2, N2O and CH4 fluxes showed a strong diurnal variation with higher emission in the daytime. A good relationship between the fluxes of CO2, N2O, CH4 and temperature was exposed in this study. | DONG Yunshe, ZHANG Shen, Ql Yuchun, CHEN Zuozhong & GENG Yuanbo1. Institute of Geography, Chinese Academy of Sciences, Beijing 100101, China:2, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China Correspondence should be addressed to Dong Yunshe | 2000 | Chinese Science Bulletin2000，45，17： | 66 |
| 6 | Vegetation and soil carbon storage in China显示文摘This study estimated the current vegetation and soil carbon storage in China using a biogeochemical model driven with climate, soil and vegetation data at 0.5°latitude-longitude grid spatial resolution. The results indicate that the total carbon storage in China's vegetation and soils was 13.33 Gt C and 82.65 Gt C respectively, about 3% and 4% of the global total. The nationally mean vegetation and soil carbon densities were 1.47 kg C/m2 and 9.17 kg C/m2, respectively, differing greatly in various regions affected by climate, vegetation, and soil types. They were generally higher in the warm and wet Southeast China and Southwest China than in the arid Northwest China; whereas vegetation carbon density was the highest in the warm Southeast China and Southwest China, soil carbon density was the highest in the cold Northeast China and southeastern fringe of the Qinghai-Tibetan Plateau. These spatial patterns are clearly correlated with variations in the climate that regulates plant growth and soil organic matter decomposition, and show that vegetation and soil carbon densities are controlled by different climatic factors. | LI Kerang, WANG Shaoqiang & CAO MingkuiInstitute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Department of Geography, Maryland University, College Park,MD 20742, USA Correspondence should be addressed to Li Kerang | 2004 | Science China Earth Sciences2004，47，1： | 60 |
| 7 | Mianlüe tectonic zone and Mianlüe suture zone on southern margin of Qinling-Dabie orogenic belt显示文摘The Mianle tectonic zone (Mianle zone), an ancient suture zone in addition to the Shangdan suture in the Qinling-Dabie orogenic belt, marks an important tectonic division geo-logically separating north from south and connecting east with west in China continent. To de-termine present structural geometry and kinematics in the Mianle tectonic zone and to recon-struct the formation and evolution history involving plate subduction and collision in the Qinling-Dabie orogenic belt, through a multidisciplinary study, are significant for exploring the mountain-building orogenesis of the central orogenic system and the entire process of the major Chinese continental amalgamation during the Indosinian. | ZHANG Guowei1, DONG Yunpeng1, LAI Shaocong1, GUO Anlin1, MENG Qingren2, LIU Shaofeng3, CHENG Shunyou1, YAO Anping1, ZHANG Zongqing4, PEI Xianzhi5 & LI Sanzhong6 1. Department of Geology, Northwest University, Xian 710069, China 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100101, China 3. Earth Science and Resource Faculty, China University of Geosciences, Beijing 100083, China 4. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 5. Changan University, Xian 710054, China 6. Qingdao University of Oceanography, Qingdao 266003, China | 2004 | Science China Earth Sciences2004，47，4： | 57 |
| 8 | Energy balance closure at ChinaFLUX sites显示文摘Network of eddy covariance observation is measuring long-term carbon and water fluxes in contrasting ecosystems and climates. As one important reference of independently evaluating scalar flux estimates from eddy covariance, energy balance closure is used widely in study of carbon and water fluxes. Energy balance closure in ChinaFLUX was evaluated by statistical regression of turbulent energy fluxes (sensible and latent heat) against available energy (net radiation, soil heat flux, canopy heat storage) and the energy balance ratio (EBR) and the frequency distribution of relative errors of energy balance (δ). The trends of diurnal and seasonal variation of energy balance in ChinaFLUX were analyzed. The results indicated that the imbalance was prevalent in all observation sites, but there were little differences among sites because of the properties variation of sites. The imbalance was greater during nocturnal periods than daytime and closure was improved with friction velocity intensifying. Generally the results suggested that estimates of the scalar turbulent fluxes of sensible and latent heat were underestimated and/or that available energy was overestimated. Finally, we discussed certain factors that are contributed to the imbalance of energy, such as systematic errors associated with the sampling mismatch, systematic instrument bias, neglected energy sinks, low and high frequency loss of turbulent fluxes and advection of heat and water vapor. | LI Zhengquan, YU Guirui, WEN Xuefa, ZHANG Leiming, REN Chuanyou & FU Yuling Chinese Ecosystem Research Network Synthesis Research Center, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Graduate School of the Chinese Academy of Sciences, Beijing 100039, China | 2005 | Science China Earth Sciences2005，48，z1： | 50 |
| 9 | Control of atmospheric CO_2 concentrations by 2050: A calculation on the emission rights of different countries显示文摘This paper is to provide quantitative data on some critical issues in anticipation of the forthcoming international negotiations in Denmark on the control of atmospheric CO2 concentrations. Instead of letting only a small number of countries dominate a few controversial dialogues about emissions reductions, a comprehensive global system must be established based on emissions allowances for different countries, to realize the long-term goal of controlling global atmospheric CO2 concentrations. That a system rooted in 'cumulative emissions per capita,' the best conception of the 'common but differentiated responsibilities' principle affirmed by the Kyoto Protocol according to fundamental standards of fairness and justice, was demonstrated. Based on calculations of various countries' cumulative emissions per capita, estimates of their cumulative emissions from 1900 to 2005, and their annual emissions allowances into the future (2006―2050), a 470 ppmv atmospheric CO2 concentration target was set. According to the following four objective indicators―total emissions allowance from 1900 to 2050, actual emissions from 1900 to 2005, emissions levels in 2005, and the average growth rate of emissions from 1996 to 2005―all countries and regions whose population was more than 300000 in 2005 were divided into four main groups: countries with emissions deficits, countries and regions needing to reduce their gross emissions, countries and regions needing to reduce their emissions growth rates, and countries that can maintain the current emissions growth rates. Based on this proposal, most G8 countries by 2005 had already expended their 2050 emissions allowances. The accu-mulated financial value based on emissions has reached more than 5.5 trillion US dollars (20 dollars per ton of CO2). Even if these countries could achieve their ambitious emissions reduction targets in the future, their per capita emissions from 2006 to 2050 would still be much higher than those of developing countries; under such circumstance, these future emissions would create more than 6.3 trillion US dollars in emissions deficits. Because of their low cumulative emissions per capita, most developing countries fall within one of the latter two groups, which means that they have leeway for making emissions decisions in the future. Although China accounts for more than 30% of the total global emissions allowance from 2006 to 2050, its total emissions can be controlled within that allow-ance by no other way than reducing its future emissions growth rates. In the end, nine key issues related to international climate negotiations were briefly addressed. | DING ZhongLi1, DUAN XiaoNan2, GE QuanSheng3 & ZHANG ZhiQiang4 1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2 The General Office of Chinese Academy of Sciences, Beijing 100864, China 3 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 4 The Lanzhou Branch of the National Science Library, the Scientific Information Center for Resources and Environment, Lanzhou 730000, China | 2009 | Science China Earth Sciences2009，52，10： | 50 |
| 10 | Ultrasonography guided percutaneous radiofrequency ablation for hepatic cavernous hemangioma显示文摘AIM: Hepatic cavernous hemangioma (HCH) is the mostcommon benign tumor of the liver and its management isstill controversial. Recent successin situ radiofrequencyablation of hepatic malignancies has led us to consider usingthis technique in patients with HCH. This study was to assessthe efficacy, safety, and complications of percutaneousradiofrequency ablation (PRFA) under ultrasonographyguidance in patients with HCH.METHODS: Twelve patients (four men and eight women,age ranged 33-56 years, mean age was 41.7 years) with 15hepatic cavernous hemangiomas (2.5 cm to 9.5 cm) weretreated using the RF-2000 generator and 10-needle LeVeenelectrode percutaneously guided by B-ultrasound. Lesionslarger than 3 cm were treated by multiple overlappingablations that encompass the entire lesion as well as a rimof normal liver tissue (approximately 0.5 cm).RESULTS: All the patients who received PRFA therapy hadno severe pain, bleeding or bile leakage during and afterthe procedures. Nine to 34 months′ follow-up (mean, 21months) by ultrasound and/or spiral CT scan demonstratedthat the ablated lesions in this group were shrunk remarkably,and the shrunken range was 38-79 % (mean, 67 % per 21months). The contrast enhancement was disappeared withinthe tumor or at its periphery in all cases on spiral CT scansobtained 3 to 6 months after treatment.CONCLUSION: The results of this study suggest that PRFAtherapy is a mini-invasive, simple, safe, and effective methodfor the treatment of selected patients with HCH. | Yan Cui Li-Yan Zhou Man-Ku Dong Ping Wang Min Ji Xiao-Ou Li Chang-Wei Chen Zi-Pei Liu Yong-Jie Xu Hong-Wen Zhang Department of Hepatobiliary Surgery,Beijing 306 Hospital,Chaoyang District,Beijing 100101,China | 2003 | World Journal of Gastroenterology2003，9，9： | 43 |
| 11 | Structure and regulatory function of plant transcription factors显示文摘The expression of inducible genes in plants is regulated by specific transcription factors at the transcrip-tional level. A typical transcription factor usually contains a DNA-binding domain, a transcription regulation domain, a dimerization site and a nuclear localization domain. These functional domains define the characteristic, localization and regulatory role of a transcription factor. Transcription factors recognize and bind to specific cis-acting elements or interact with other proteins, and then activate or repress the transcription of target genes by their functional domains. In recent years, elucidation on the structure and function of transcription factors has become an important subject in plant molecular biology. | LIU Qiang, ZHANG Guiyou & CHEN ShouyiDepartment of Biological Science and Biotechnology, Tsinghua Univorsity, Beijing 100084, China Department of Biological Science and Biotechnology, State Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China Institute of Genetics, Chinese Academy of Sciences, Beijing 100101, China | 2001 | Chinese Science Bulletin2001，46，4： | 36 |
| 12 | Characterizations and identification of the candidate gene of rice thermo-sensitive genic male sterile gene tms5 by mapping显示文摘Previous study indicated that the thermo-sensitive genic malesterile(TGMS) gene in rice was regulated by temperature.TGMS rice plays an important role in hybrid rice production,because the application of the TGMS system in two-line breeding is laborsaving,timesaving,simple,inexpensive,efficient,and eliminating the limitations of the cytoplasmic male sterility(CMS) system.'AnnongS' is the first discovered and deeply studied TGMS rice lines in China.'AnnongS-1' and 'Y58S',two derivatives of TGMS line AnnongS,were both controlled by a single recessive gene named tms5,which was genetically mapped on chromosome 2.In this study,three populations('AnnongS-1' × 'Nanjing11','Y58S' × 'Q611',and 'Y58S' × 'Guanghui122') were developed and used for the molecular fine mapping of the tms5 gene.By analyzing recombination events in the sterile individuals using a total of 125 probes covering the tms5 region,the tms5 gene was physically mapped to a 19-kb DNA fragment between two markers 4039-1 and 4039-2,which were located on the BAC clone AP004039.After the construction of the physical map between two markers 4039-1 and 4039-2,a member(ONAC023) of the NAC(NAM-ATAF-CUC-related) gene family was identified as the candidate gene of the tms5 gene. | YANG Qing-kai1,LIANG Chun-yang1,LI Jun1,JIN De-min1,AHUANG Wen2,DENG Qi-yun2,WANG Bin1(1.The State Key Laboratory of Plant Genomics,Institute of Genetics and Developmental Biology,Chinese Academy of Sciences,Beijing,100101 2. Hunan Hybrid Rice Research Center,Changsha 410125) | 2007 | 湖南农业大学学报(自然科学版)2007，33，S1： | 34 |
| 13 | A study of interaction between surface water and groundwater using environmental isotope in Huaisha River basin显示文摘The surface water and groundwater are important components of water cycle, and the interaction between surface water and groundwater is the important part in water cycle research. As the effective tracers in water cycle research, environmental isotope and hydrochemistry can reveal the interrelationships between surface water and groundwater effectively. The study area is the Huaisha River basin, which is located in Huairou district, Beijing. The field surveying and sampling for spring, river and well water were finished in 2002 and 2003. The hydrogen and oxygen isotopes and water quality were measured at the laboratory. The spatial characteristics in isotope and evolution of water quality along river lines at the different area were analyzed. The altitude effect of oxygen isotope in springs was revealed, and then using this equation, theory foundation for deducing recharge source of spring was estimated. By applying the mass balance method, the annual mean groundwater recharge rate at the catchment was estimated. Based on the groundwater recharge analysis, combining the hydrogeological condition analysis, and comparing the rainfall-runoff coefficients from the 1960s to 1990s in the Huaisha River basin and those in the Chaobai River basin, part of the runoff in the Huaisha River basin is recharged outside of this basin, in other words, this basin is an un-enclosed basin. On the basis of synthetically analyses, combining the compositions of hydrogen and oxygen isotopes and hydrochemistry, geomorphology, geology, and watershed systems characteristics, the relative contributions between surface water and groundwater flow at the different areas at the catchments were evaluated, and the interaction between surface water and groundwater was re- vealed lastly. | SONG Xianfang1, LIU Xiangchao1, 2, XIA Jun1, YU Jingjie1 & TANG Changyuan1, 3 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences and Natural Re- sources Research, Chinese Academy of Sciences, Beijing 100101, China 2. College of River and Ocean, Chongqing Jiaotong University, Chongqing 400074, China 3. Chiba University, Chiba 263-8522, Japan | 2006 | Science China Earth Sciences2006，49，12： | 34 |
| 14 | Development of distributed time-variant gain model for nonlinear hydrological systems显示文摘In this paper, a rainfall-runoff modeling system is developed based on a nonlinear Volterra functional series and a hydrological conceptual modeling approach. Two models, i.e. the time-variant gain model (TVGM) and the distributed time-variant gain model (DTVGM) that are built on the platform of Digital Elevation Model (DEM), Remote Sensing (RS) and Unit Hydro-logical Process were proposed. The developed DTVGM model was applied to two cases in the Heihe River Basin that is located in the arid and semiarid region of northwestern China and the Chaobai River basin located in the semihumid region of northern China. The results indicate that, in addition to the classic dynamic differential approach to describe nonlinear processes in hy-drological systems, it is possible to study such complex processes through the proposed sys-tematic approach to identify prominent hydrological relations. The DTVGM, coupling the advan-tages of both nonlinear and distributed hydrological models, can simulate variant hydrological processes under different environment conditions. Satisfactory results were obtained in fore-casting the time-space variations of hydrological processes and the relationships between land use/cover change and surface runoff variation. | XIA Jun1, 2, WANG Gangsheng1, TAN Ge1, YE Aizhong2 & G. H. Huang3 1. Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2. State Key Laboratory of Water Resources & Hydropower Engineering Sciences, Wuhan University, Wuhan 430072, China 3. Faculty of Engineering, University of Regina, 3737 Wascana Parkway, Regina, Sask., S4S 0A2, Canada Correspondence should be addressed to Xia Jun | 2005 | Science China Earth Sciences2005，48，6： | 32 |
| 15 | Diversity and ecological distribution of endophytic fungi associated with medicinal plants显示文摘A total of 973 isolates of endophytic fungi were recovered from 1144 tissue fragments of the six me-dicinal plant species belonging to 4 families collected in the Beijing Botanical Garden. Of these isolates 778 sporulated and were identified into 21 taxa by morphological characteristics. Among the taxa 11 belonged to Coelomycetes, 6 to Ascomycetes, and 4 to Hyphomycetes. Various numbers of endophytic fungi (5―8 taxa) were obtained from each plant. Alternaria alternata was the dominant species in the 6 plants, and Microsphaeropsis conielloides was also dominant in Eucommia ulmoides. There were high colonization rates (47.9%―63.1%) and isolation rates (0.7―0.93) of endophytic fungi, and they were conspicuously higher in twigs than those in leaves in the 6 plants examined. The colonization and isolation rates of endophytic fungi increased with the twig age. The results based on the analyses of cluster and Sorenson's similarity coefficients indicated that some endophytic fungi showed a certain degree of host and tissue preference. | SUN JianQiu1,2,3, GUO LiangDong1, ZANG Wei2,3, PING WenXiang4 & CHI DeFu3 1 Systematic Mycology and Lichenology Laboratory, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China 2 College of Life Science and Engineering, Qiqihar University, Qiqihar 161006, China 3 College of Forestry, Northeast Forestry University, Harbin 150040, China 4 College of Life Science, Heilongjiang University, Harbin 150080, China | 2008 | Science China(Life Sciences)2008，51，8： | 34 |
| 16 | Effects of the Biot and the squirt-flow coupling interaction on anisotropic elastic waves显示文摘Considering the velocity anisotropy of the solid/fluid relative motion and employment of the BISQ theory based on the one-dimensional porous isotropic case, we establish a two-phase anisotropic elastic wave equation to simultaneously include the Biot and the squirt mechanisms in terms of both the basic principles of the fluid’s mass conservation and the elastic-wave dynamical equations in the two-phase anisotropic rock. Numerical results, while the Biot-flow and the squirt-flow effects are simultaneously considered in the transversely isotropic (Tl) poroelastic medium, show that the attenuation of the quasi P-wave and the quasi SV-wave strongly depend on the permeability anisotropy, and the attenuation behavior at low and high frequencies is contrary. Meanwhile, the attenuation and dispersion of the quasi P-wave are also affected seriously by the anisotropic solid/fluid coupling additional density. | YANG Dinghui & ZHANG Zhongjie Department of Mathematical Sciences, Tsinghua University, Beijing 100084, China Institute of Geophysics, Chinese Academy of Sciences, Beijing 100101, China | 2000 | Chinese Science Bulletin2000，45，23： | 33 |
| 17 | S-wave velocity and Poisson's ratio structure of crust in Yunnan and its implication显示文摘Receiver function of body wave under the 23 stations in Yunnan was extracted from 3-component broadband digital recording of teleseismic event. Thus, the S-wave velocity structure and distribution characteristics of Poisson's ratio in crust of Yunnan are obtained by inversion.The results show that the crustal thickness is gradually thinned from north to south. The crustal thickness in Zhongdian of northwest reaches as many as 62.0 km and the one in Jinghong of further south end is only 30.2 km. What should be especially noted is that there exists a Moho upheaval running in NS in the Chuxiong region and a Moho concave is generally parallel to it in Dongchuan. In addition, there exists an obvious transversal inhomogeneity for the S-wave veIocity structure in upper mantle and crust in the Yunnan region. The low velocity layer exists not only in 10.0-15.0 km in upper crust in some regions, but also in 30.0-40.0 km in lower crust.Generally, the Poisson's ratio is on the high side, however it has a better corresponding relation to the crustal velocity structure. An obvious block distribution feature is still shown on such a high background of Poisson's ratio. It is discovered by synthetically analyzing the velocity structure and Poisson's ratio distribution that there are high Poisson's ratio and complicated crust-mantle velocity structure feature in the Sichuan-Yunnan Diamond Block with Xiaojiang fault to be the east boundary and Yulong Snow Mountain fault to be the west boundary besides the frequent seismicity. This feature differs obviously from that of surrounding areas, which would provide geophysical evidence to deeply study the eastwardly flowage of lithospheric substances in the Qinghai-Tibet Plateau. | HU Jiafu, SU Youjin, ZHU Xiongguan & CHEN Yun Geophysical Department of Yunnan University, Kunming 650091, China Seismological Bureau of Yunnan Province, Kunming 650041, China Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100101, China | 2005 | Science China Earth Sciences2005，48，2： | 30 |
| 18 | Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation显示文摘Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method. | Ge Yong Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences & Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Cheng Qiuming Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Earth Systems and Mineral Resource Engineering Lab, China University of Geosciences, Wuhan 430074, China Zhang Shenyuan Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Department of Resource and Earth Science, China University of Mining & Technology, Beijing 100083, China | 2004 | Journal of China University of Geosciences2004，15，4： | 28 |
| 19 | ^(40)Ar-^(39)Ar thermochronology of two ductile shear zones from Yiwulüshan,West Liaoning Region: Age constraints on the Mesozoic tectonic events显示文摘Two ductile shear zones trending EW and NNE respectively not only controlled the tectonic framework of the northern North China, but also constrained the geody-namic background for gold mineralization in this region. Field observations and microstructural analyses reveal that the EW trending ductile shear zones are mainly contributed to dextral compressional deformation resulting from top-to-the-southeast oblique thrust shearing, whereas the NNE trending ones are genetically related to sinistral strike-slip and extensional faulting. One sample from the former yielded an 40Ar-39Ar plateau age of (219±4) Ma (Bi) and two samples from the latter gave 40Ar-39Ar plateau ages of (116± 2) Ma (Bi) and (127±3) Ma (Bi). These ages provide constraints on the top-to-the-southeast oblique thrusting event occurring in Late Triassic and the sinistral extensional and strike-slip faulting event which occurred in Early Cretaceous. | ZHANG Xiaohui, LI Tiesheng & PU ZhipingResearch Center of Mineral Resources Exploration, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100101, China Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 51 | 2002 | Chinese Science Bulletin2002，47，13： | 24 |
| 20 | History of the temperature-dependence of susceptibility and its implications: Preliminary results along an E-W transect of the Chinese Loess Plateau显示文摘An investigation of rock magnetic properties using the temperature-dependence ofsusceptibility (TDS) and the coercivity of different IRM components was conducted on samples ofthe Malan loess (L1) and the last interglacial soil (S1) along an E-W transect of the Chinese LoessPlateau. We find that the behavior of the TDS is useful in identifying maghemite (γ-Fe2O3) in bothloess and paleosol, and that it can be used as a new proxy of the degree of pedogenesis, which isclosely linked to climatic conditions. Based on results from the TDS, we conclude that (1) thedetrital magnetite grains predominate in the L1 unit to the west of Liupan Mts, where theweathering and pedogenetic processes were weakest; (2) a comparable degree of pedogenesisexists in the L1 at the east of the Liupan Mts and the S1 at the west of the Liupan Mts; (3) a higherconcentration of maghemite is found in the S1 unit at the eastern sections, suggesting that the localclimate was warmer and more humid in this interval. In addition, we propose that TDSmeasurements can be used as a rapid means of determining the reliability of the paleomagneticsecular variation (PSV) record in loess/poleoso/sequenees. | ZHU Rixiang LIN Mian PAN Yongxin 1) Institute of Geophysics. Chinese Academy of Sciences. Beijing 100101 2) Institute of Mechanism. Chinese Academy of Sciences, Beijing 100080 | 1999 | Chinese Science Bulletin1999，44，S1： | 24 |
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