共查询到20条相似文献，搜索用时 15 毫秒
1.
渭河盆地GPS(1990~2015年)水平运动速率为4.3~11.6 mm/a，方向在107.8°E和110.5°E依次由西部的SEE转为中部的SE及东部的近E向。1980~2014年水准资料揭示，该地区垂向以继承性运动为主，速率-4.6~6.2 mm/a。鄂尔多斯地块以3 mm/a抬升，内部差异运动小于1 mm/a；盆地相对其以5 mm/a下沉，相对秦岭以4 mm/a下沉。垂向运动在凹陷和凸起区表现为四象限特征，断块/断裂交接处差异运动大、地震多发，西、南部断裂活动大于东、北部。岐山-马召等断裂以差异运动为主，渭河断裂中段达5 mm/a，其他断裂在3 mm/a以内。 相似文献
2.
《山地科学学报》2021,(10)
Nitrogen retention within a watershed reduces the amount of N exported to the ocean; however, it worsens environmental problems, including surface water eutrophication, aquifer pollution, acid rain, and soil acidification. Here, we adopted the Soil and Water Assessment Tool(SWAT) model to describe the riverine N output and retention effects in the Shanmei Reservoir Basin, a subtropical mountainous basin located in Quanzhou City, Southeast China. The results revealed that farmlands and orchards in the upstream and central parts of the basin were the dominant land use types, which contributed large N yields. Fertilizer application was the key source of riverine N output and N retention within the basin. On average, approximately 64% of anthropogenic N inputs were retained within the basin, whereas 36% of total N was exported to the downstream and coastal areas. The average N retention efficiency was 80% in a dry year, and within the year, N retention occurred in spring and summer and N release occurred in autumn and winter. The annual variation in N retention within the basin was largely dominated by changes in rainfall and runoff, whereas the seasonal characteristics of N retention were mainly affected by fertilization. Even with a large decrease in fertilizer application, owing to the contributions of the residual N pool and river background, the riverine N output still maintained a certain base value. The effects of precipitation, land use types, and agricultural fertilizer on N retention should be comprehensively considered to implement reasonable N management measures. 相似文献
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LULa-chang 《中国地理科学(英文版)》2002,12(4):309-314
Since China opening to outside world, the economy in the Pearl(Zhujiang) River Delta(PRD) has been dou-ble digit growth. It has been known as one of mature fast growth areas in the world and become the model and hope of Chi-nese reform and opening to outside world. The regional development in PRD is the outcome of polarization effects. The polar-ization effects actually are extension of international regional division and a combination of Hongkong‘‘s influence and re-form and open-door policies on the mainland. Since the 1990s, driven by knowledge-based economy, the PRD has furtheradjusted the industrial structure and achieved good progress in upgrading industrial structure. Its high technology industryhas developed quickly and the economic internationalization has deepened, meanwhile, the region is going through transforma-tion and some new trends have begun to appear, which include: university towns springing up, industrial globalization andthe construction of Hi-tech development zones. The paper suggests that with the economic growth changing from relying onthe low level production elements to relying on high level production elements, the regional policies in GuangdongProvince should develop correspondingly: 1) make a plan to prohihite the blind construction in innovative spatial construc-tions; 2) make measures to attract the overseas talents to establish a pool of talent; 3) work out the favorable policies forabsorbing larger capital; 4) formulate the policy of attracting a cluster of industries to speed up the upgrade of industrialdevelopment. 相似文献
4.
谢志东 《极地研究(英文版)》2009,20(2):172-186
Shock metamorphism resulting from hypervelocity collisions between planetary bodies, is a fundamental processes in the solar system. The term "shock metamorphism" is used to describe all changes in rocks and minerals resulting from the passage of shock waves. Most meteorites have experienced collisions and have a record of shock metamorphism, which includes brecciation, deformation, phase transformation, local melting and crystallization. The key to reading this record is to use the shock features to estimate the pressure and duration of shock event. In this paper, the history of the study of shock metamorphism is reviewed; basic knowledge of shock physics is discussed; recent 10 years' studies of shock-induced melt veins are summarized; and finally a short note to the shock metamorphism in general is given. 相似文献
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Livelihood differentiation between two villages in Yesanpo Tourism District in China 总被引：1，自引：0，他引：1
The rapidly developing rural tourism industry in China has deeply influenced the livelihoods of rural households. This study compares the impact of rural tourism development in poor areas on the farmers’ livelihoods, based on the Sustainable Livelihoods Framework proposed by the United Kingdom’s Department for International Development. Gougezhuang, a tourist village, and Jiaojiekou, a non-tourist village, both located in Yesanpo Tourism District in the state-level povertystricken Laishui County, Hebei Province, were selected as case studies. The livelihood models of the two villages show great differentiation after 20 years of tourism development. Gougezhuang Village has been driven by the tourism industry and farmers are employed locally, enjoying a relatively higher-income life, with a developmental livelihood model. In contrast, farmers in Jiaojiekou Village earn their living mainly by leaving home to work in the city. They have a low income, with a survival livelihood model, supported by part-time business. Considering that the two villages are adjacent and have similar development backgrounds, the analysis results indicate that rural tourism has an apparent locationspecific effect on poverty alleviation and socioeconomic development, but the development of rural tourism is limited regarding large-scale poverty alleviation efforts in poor areas. To implement a propoor- tourism strategy and achieve sustainable development, it is necessary to implement comprehensive management measures to change the local conditions of rural settlements and make full use of the spillover effect of tourist consumption. 相似文献
6.
为查明济南市降水量变化特征和趋势,采用累积距平分析、Mann-Kendall法、集合经验模态分解(EEMD)等方法对1956—2018年济南市降水量进行综合分析。结果表明,济南市降水量呈上升的变化趋势,倾斜率为8.35mm/10a,其中1956—1961年、1967—1972年和1981—1993年为降水偏少时期,1962—1966年、1973—1980年和1994—2018年为降水偏多时期,1961年和1990年发生过2次降水由偏少到偏多的突变,预测未来济南市降水量仍然以偏多为主;济南市降水量存在2.62a,5.73a,10.50a和36.50a的周期分量,其中5.73a分量通过了95%的置信区间检验,周期性显著,对降水量贡献率为48.73%;济南市降水量整体呈现先减少后增多的变化趋势,且后期的升高幅度小于前期的下降幅度。 相似文献
7.
《山地科学学报》2021,(10)
On 28 th July 2018, a massive landslide occurred in a mountainous area in Northern Thailand. The landslide after ten days of heavy rainfall generated the movement of uphill mountain soil into the populated village. This study presents a comprehensive failure analysis of local rainfallinduced landslides based on topographical and geological information. Rainfall measurement data were gathered from two rainfall stations close to the study area. The rainfall records show that the total monthly rainfalls in 2018 were significantly higher than the average monthly rainfalls over the past decade. Site investigation started with an unmanned aerial photogrammetric survey to generate a digital elevation model. Then, dynamic probing test, microtremor survey, and electrical resistivity survey were carried out along undisturbed soils beside the failed slope to evaluate the thickness of the soft soil cover on top of the rock basement. During the site survey, residual soil samples were collected to determine engineering properties in the laboratory. Finally, a slope stability analysis was performed to assess the landslide hazard based on the results of aerial photogrammetric survey, field exploration, and laboratory tests. The slope stability analysis and rainfall records revealed that the Huay Khab landslide was mainly caused by an increase in the water content of residual soils due to the prolonged rainfall which led to a sharp decrease in the shear strength. This leads to the conclusion that the proposed landslide investigation program could be used to assess the potential of landslide failure due to prolonged rainfall on a local scale. 相似文献
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The fresh snow density was observed with snow analyzer (Snow Fork) at Tianshan Station for Snowcover and Avalanche Research, Chinese Academy of Sciences from February 21 to March 5, 2009. Results show that fresh snow density increases from the 5th h to the 291st h after the snowfall, with an average rate of increase of 4.0×10-4 g/(cm3·h) (R2 = 0.943). Analysis shows that fresh snow density is negatively correlated with the compac-tion rate of fresh snow (R2 = -0.960). Inversely, it is positively correlated ... 相似文献
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ＤＩＳＴＲＩＢＵＴＩＶＥＴＥＮＤＥＮＣＹＯＦＥＬＥＭＥＮＴＣＯＮＣＥＮＴＲＡＴＩＯＮＳＩＮＬＩＭＥＳＴＯＮＥＳＯＩＬＳＩＮＥＡＳＴＥＲＮＣＨＩＮＡＷｅｎＹａｎｍａｏ（温琰茂）；ＺｅｎｇＳｈｕｉｑｕａｎ（曾水泉）；ＰａｎＳｈｕｒｏｎｇ（潘树荣）；Ｌｕｏ... 相似文献
12.
Resource-dependent cities(RCs)are a vulnerable group of urban settlements that often face population shrinkage;however,population changes in RCs in China are not well understood.This study offers new insight into this matter through a robust analysis that features a longer time scale,a larger sample of RCs,and a finer unit of analysis.It finds new evidence that problems of population shrinkage in RCs are more serious than previous literature has suggested.Approximately 30%of the studied units have experienced either long-term or short-term population shrinkage,and many more are experiencing a slowing down of population growth.Problems are especially common among three types of RCs:the resource-depleted RCs,the forestry-based RCs,and RCs in Northeast China.These results underscore transition policy inadequacies in addressing population loss,and call for a more comprehensive and diversified population policy that tackles the multifaceted factors that contribute to population shrinkage,including lack of industrial support,maladjustment to market oriented reformation,poor urban environment and natural population decline. 相似文献
13.
Marco PILOTTI Andrea MARANZONI Luca MILANESI Massimo TOMIROTTI Giulia VALERIO 《山地科学学报》2014,(6):1429-1441
Dam-break analysis is of great importance in mountain environment,especially where reservoirs are located upstream of densely populated areas and hydraulic hazard should be assessed for land planning purposes.Accordingly,there is a need to identify suitable operative tools which may differ from the ones used in flat flood-prone areas.This paper shows the results provided by a 1D and a 2D model based on the Shallow Water Equations（SWE） for dam-break wave propagation in alpine regions.The 1D model takes advantage of a topographic toolkit that includes an algorithm for pre-processing the Digital Elevation Model（DEM） and of a novel criterion for the automatic cross-section space refinement.The 2D model is FLO-2D,a commercial software widely used for flood routing in mountain areas.In order to verify the predictive effectiveness of these numerical models,the test case of the Cancano dam-break has been recovered from the historical study of De Marchi（1945）,which provides a unique laboratory data set concerning the consequences of the potential collapse of the former Cancano dam（Northern Italy）.The measured discharge hydrograph at the dam also provides the data to test a simplified method recently proposed for the characterization of the hydrograph following a sudden dam-break. 相似文献
14.
Community Participation in Forest Resource Management in Nepal 总被引：2，自引：1，他引：1
KeshavL.Maharjan 《山地科学学报》2005,2(1):32-41
Livelihood of the people in Nepal hills depends much upon forest resources in addition to farming as forest plays a critical role in the well being of the farming households where access to alternative sources, such as energy for cooking, nutrition for animals, materials for fertilizer and constructing materials for shelter, are limited. Thus, the well being of the people in the hills is directly affected by the management of these forest resources. This issue was addressed in this paper by examining the forest resource management practices and its effect on well being of rural people in two different stages in a village lying in the steep hill of Mahabharat Range in the southern hills of Kathmandu valley, Lalitpur District. The main ethnic/caste groups in the villageare Brahmin/Chhetri (high Hindu caste),Magar/Tamang (Tibeto Burmans) and Kami (occupational caste: cobbler). Currently there are four community forest users groups, with mixed ethnic membership, organized to manage the forest resources. The endowments, weak institutional settings, before 1990 helped the Bhramins, Magars and Tamangs to get access into the private forest endowment, which made them easy to get access to the forest resources, mainly fuel wood, fodder and timber in 1990 and enhanced their well beings. But the socially backward Kami could not get benefit from the institutions that existed during that time and had less chance to enhance their well beings. After the set up of different endowments during late 199os, i.e.,hand over of forest management to users groups in line with the concept of community forest,environment to use the forest resources became better for all the groups, along with the management of the forest. This enhanced the well beings of all the groups in the study village. However, the ability of Kami to use the forest resources to enhance their well beings was still lacking behind. The reason was partially due to the difference in endowments carried over from the endowments before 199o, and partly due to their occupational work and location of their settlements. 相似文献
15.
The wet-dry changes in recent 40 years in taklimakan area 总被引：6，自引：0，他引：6
IINTRODUCTIONAlongwiththePetroleumexploitationofTarimBasin,consideringaboutwaterresources,peoplepaidmuchattentiontothestudyofthemodernclimatechangeinTaklimakanarea.SomePeoplehaddonemanalySeSwiththemeteorologicaldatainthearea(Yang,1992;Jietal.,1992;Zheng,1991;Xue,1989;Li,1989;Wenetal.,1988).BasedontheO~ionaldstaofprecipitationinrecent40years,thisPaperCarefullyanalyZedthewet-drychangeinrecentseveraldeCadesinTaklilnakanareaanditsneighdringareas(thenorthernXinjiang,QinghaiandGansuPro… 相似文献
16.
We characterized variations in bacterioplankton community composition(BCC) in mesocosms subject to three different treatments. Two groups contained fish(group one: Cyprinus carpio; group two: Hypophthalmichthys molitrix); and group three, the untreated mesocosm, was the control. Samples were taken seven times over a 49-d period, and BCC was analyzed by PCR-denaturing gradient gel electrophoresis(DGGE) and real-time quantitative PCR(q PCR). Results revealed that introduction of C. carpio and H. molitrix had a remarkable impact on the composition of bacterioplankton communities, and the BCC was significantly diff erent between each treatment. Sequencing of DGGE bands revealed that the bacterioplankton community in the different treatment groups was consistent at a taxonomic level, but differed in its abundance. H. molitrix promoted the richness of Alphaproteobacteria and Actinobacteria, while more bands affiliated to Cyanobacteria were detected in C. carpio mesocosms. The redundancy analysis(RDA) result demonstrated that the BCC was closely related to the bottom-up(total phosphorus, chlorophyll a, phytoplankton biomass) and top-down forces(biomass of copepods and cladocera) in C. carpio and control mesocosms, respectively. We found no evidence for top-down regulation of BCC by zooplankton in H. molitrix mesocosms, while grazing by protozoa(heterotrophic nanoflagellates, ciliates) became the major way to regulate BCC. Total bacterioplankton abundances were significantly higher in C. carpio mesocosms because of high nutrient concentration and suspended solids. Our study provided insights into the relationship between fish and bacterioplankton at species level, leading to a deep understanding of the function of the microbial loop and the aquatic ecosystem. 相似文献
17.
张声怡 《广东海洋大学学报》2005,25(5):82-88
“吏隐”作为大历十才子的生活特征之一,也成为他们创作的题材,这与当时方外隐逸诗人因其不同的人生观照所创作的诗作相映成趣。方外隐逸诗人又可分为隐士诗人和诗僧两个群体,大历十才子和方外隐逸诗人之间体现出了完全不同的生命体验,方外隐逸诗人对真隐精神的写作与十才子的“伪隐”形成了鲜明的对比,就后者来说,现实的功利主义态度和价值上的物质取向使其隐逸诗作之精神内涵大打折扣。 相似文献
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本文利用全国1∶100万土地利用数据和1∶400万土壤肥力综合质量数据,从耕地的地形特征和土壤肥力两个角度,对贫困地区和非贫困地区的耕地自然质量进行比较研究。研究表明:贫困地区平原型、丘陵型耕地比重较低、山地型和陡坡型耕地比重较高;贫困地区耕地土壤肥力的平均水平和非贫困地区差别不大,但土壤肥力好和较好的耕地所占比重较小。本文还建立了包括地形特征和土壤肥力综合质量两个因素的耕地自然质量评价指数,从县域尺度对全国耕地自然质量进行定量评价,并发现贫困地区耕地自然质量评价指数在低值区集中的特征更为显著。 相似文献
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会宝岭铁矿为隐伏矿床,发育2条主矿带,矿带总体走向280°～290°,平行展布,相向而倾,表现为不对称向斜构造特征。两条矿带包含南北两翼5个矿体,其南翼矿带沿走向自西向东具有逐渐变宽的趋势,而北翼矿带自西向东则有收缩变窄的趋势。矿床赋存于泰山岩群山草峪组中,产状与地层产状基本一致,上覆盖层为青白口纪至早寒武纪沉积地层。矿带顶底板围岩为黑云变粒岩或黑云角闪片岩。本文在全面总结分析会宝岭铁矿床以往成果资料和找矿方法的基础上,分析了区域成矿规律,研究了矿区内构造对铁矿的控制规律,探讨了铁矿床成因,确定了区内主要找矿标志,建立了勘查模型,指出了找矿方向。 相似文献