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严寒地区抽水蓄能电站防冰害措施研究 被引量:4
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作者 杨子强 王可 李伟 《水力发电》 北大核心 2018年第6期54-56,61,共4页
通过对西龙池抽水蓄能电站上水库开展为期3年的冰情及电站运行观测,以及在原型上开展水流扰动试验,结合国内类似工程的调研成果,提出严寒地区抽水蓄能电站合理的防冰害措施,为其他类似工程提供参照和借鉴。
关键词 冰害 动水带 机组运行 水流扰 抽水蓄能电站
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鲁西某煤矿充水因素分析
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作者 陈冲 李文尧 徐世光 《价值工程》 2017年第16期194-195,共2页
水害防治工作一直是煤矿安全生产工作中的重中之重[1]。本文详细论述了该井田的充水因素,通过对充水因素的分析,得出了该煤矿安全生产的主要充水含水层,为矿井安全生产提供可靠的理论指导,为这类煤矿安全生产的防水工作提供参考。
关键词 煤矿 含水层 水文地质条件 裂隙导水带
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Vegetation-Climate Relationship and Its Application in the Division of Vegetation Zone in China 被引量:39
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作者 方精云 宋永昌 +1 位作者 刘鸿雁 朴世龙 《Acta Botanica Sinica》 CSCD 2002年第9期1105-1122,共18页
Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundat... Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes. 展开更多
关键词 China dynamic vegetation regionalization arid/humid climate northern limit of subtropical zone Qinling Mountain_Huaihe River line thermal climate vegetation_climate relationship vegetation regionalization vegetation zone
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Origin of beaded tafoni in cliffs of Danxia landscapes,Longhushan Global Geopark, South China 被引量:9
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作者 GUO Fu-sheng CHEN Liu-qin +1 位作者 XU Huan LIU Xin 《Journal of Mountain Science》 SCIE CSCD 2018年第11期2398-2408,共11页
The tafoni that develop in sandstone cliffs have attracted the interest of both scientists and the general public. A necklace-like tafone system, referred to here as beaded tafoni, has developed in the prominent cliff... The tafoni that develop in sandstone cliffs have attracted the interest of both scientists and the general public. A necklace-like tafone system, referred to here as beaded tafoni, has developed in the prominent cliffs of the Danxia landscapes within the Longhushan Global Geopark in the subtropical zone of South China. This paper presents a new model of the formation of this system of extraordinary beaded tafoni. The cliffs of the Danxia landscapes of the study area are composed of an alluvial conglomerate(i.e.,red beds). These Danxia landscapes have subrounded summits that are covered by vegetation and experience a nearly vertical water flow induced by gravity. Erosion and collapse of the outsized gravels and concentrated pebbles in the red beds give rise to the initial development of the beaded tafoni. The tafoni then become rounded and beaded as a result of reworking and decay by fluvial outwash. During storms, intense water flows run vertically down the cliffs and generate a whirling motion in the tafoni.Consequently, the inside walls of the tafoni gradually become wider and smoother. During the late development stage, the beaded tafoni tend to become indistinct or disappear because of the interconnection of the tafoni and subsequent merging with the bedding-controlled cavities. 展开更多
关键词 Beaded tafoni Alluvial red beds Danxia landscape Longhushan Global Geopark
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Dynamics of Lumber Production from Buttressed-Stumps of Logging Residues Using a Fuel Powered Horizontal Mobile Bandsaw Machine
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作者 Reynolds Okai Esi Ametoxe Banful Stephen Jobson Mitchual 《Journal of Environmental Science and Engineering(A)》 2016年第2期82-89,共8页
Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging re... Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging residues of a previous logging activity by a timber firm was undertaken with the objective of determining the suitability of utilizing buttressed-stumps as raw material for the timber industry. A horizontal mobile bandsaw machine was used to process the buttressed-stumps into lumber. The machine was characterized by a thin-kerr sawing technology (kerf-width 1.6 mm) compared to the conventional bandsaw machines of kerr-widths ranging from 3.0-4.5 mm. Lumber value and volume yields, fuel consumption rate, frequency of tool replacement and lumber production rate were assessed. Results indicated that there is the potential to increase timber production from logging residues by utilizing buttressed-stumps. Lumber value and volume yields of eight timber species investigated in this study ranged from 5%-31% and 34%-54% respectively. Fuel consumption rate which increased with increasing wood density, ranged from 5-14.5 liters/m3 of lumber produced. Frequency of saw replacement increased with increasing wood density. The number of saws required to produce one cubic meter of lumber, ranged from 1 to 7. Lumber production rate ranged from 0.10-0.38 m3/hour, increasing with decreasing wood density. 展开更多
关键词 Buttressed-stumps downstream processing logging residues lumber value and volume yields mobile bandsawmachine.
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3D Numerical Modeling of Hydrodynamics in the Dubai Coastal Zone
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作者 Priyantha Gunaratna Thamali Gunaratna 《Journal of Shipping and Ocean Engineering》 2012年第5期283-292,共10页
A three dimensional hydrodynamic was developed for the Dubai coastal zone including the Dubai Creek. The model is based on DHI (Danish Hydraulic Institute's) MIKE 3 HD (FM) modeling software. The model was subjec... A three dimensional hydrodynamic was developed for the Dubai coastal zone including the Dubai Creek. The model is based on DHI (Danish Hydraulic Institute's) MIKE 3 HD (FM) modeling software. The model was subjected to extensive calibration making use of recorded water levels, currents, water temperature and salinity. A high level of accuracy in calibration was achieved as indicated by the computed statistical error parameters at all recording stations. The model results combined with field recording of water levels were used to ascertain tidal wave propagation pattern in the Dubai coastal zone and in and out of the Dubai creek. This model will be a very useful tool in assessing impacts of planned connection of artificial waterways to the Dubai Creek. 展开更多
关键词 HYDRODYNAMICS numerical modeling tidal constituents tidal wave propagation.
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Population Dynamics and Condition Factor of Oreochromis niloticus L. in Two Tropical Small Dams, Tigray (Northern Ethiopia)
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作者 Atakilt Berihun Tadesse Dejenie 《Journal of Agricultural Science and Technology(B)》 2012年第10期1062-1072,共11页
Several dams have been constructed in Ethiopia, East Africa to support electricity and/or irrigation. Fishes were introduced to some of these dams. Thus, the objective of this study was to assess the dynamics and cond... Several dams have been constructed in Ethiopia, East Africa to support electricity and/or irrigation. Fishes were introduced to some of these dams. Thus, the objective of this study was to assess the dynamics and condition factor of Oriochromis niloticus in Korir and Lailay Wukro Dams, Northern Ethiopias. The study was conducted by deploying two gill net, every month in the littoral and pelagic zones of the two dams from August 2011 to May 2012. A total of 524 O. niloticus, 278 from Lailay Wukro and 246 from Korir dams were collected. The monthly catch per unit effort (CPUE) showed significant variation among months, the highest catch was in May and the least was in January 2012 (P 〈 0.000). Catches of fish encountered higher in the littoral (69.1%) than in the pelagic zones (30.9%) (P 〈 0.000). The condition factor of O. niloticus in the two reservoirs remains high, in Korir 2.05 and in Lailay Wukro 1.65 (P 〈 0.000). In these small tropical dams, O. niloticus mature as they are smaller in size (Ls0: TL average 22.5 cm). The ratio of male to female was 1.3:1 (P 〈 0.016). The two dams have favorable condition for high production of O. niloticus. This high potential for fish production in the dams may be sustainable if the local authorities set a regulation to control the illegal fishing activity. 展开更多
关键词 Condition factor CPUE IMMATURE MATURE Oreochromis niloticus.
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Research on Present Activity Characteristics of Heizi Fault and Discussion of Its Relative Problems
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作者 Jiang Jingxiang, Wen Heping, Ying Guanghua, and Liu HuiSeismological Bureau of Xinjiang Uygur Autonomous Region,Urumqi 830011, China 《Earthquake Research in China》 2002年第1期39-46,共8页
Based on other previous researches, we recalculate the micro-displacement along the Heizi fault with recent deformation data of the Heizi reservoir. The result shows that activity characteristics of Heizi fault has ch... Based on other previous researches, we recalculate the micro-displacement along the Heizi fault with recent deformation data of the Heizi reservoir. The result shows that activity characteristics of Heizi fault has changed greatly since 1973 and have experienced four phases. The third phase is characteristics of normal fault, and others characteristic of reverse faults. Constructing the reservoir dam and reservoir sluice has important effect on present activity of the fault, even changed the activity characteristics of faults in some phases. Seismicity has some effect on deformation data and fault activity. 展开更多
关键词 Heizi fault Heizi reservoir Spanning fault measurement Fault activity characteristics
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Petroleum Pollution of Groundwater in Zibo and Its Prevention Measures 被引量:1
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作者 徐建芳 武强 李铎 《Journal of China University of Mining and Technology》 2003年第1期24-28,共5页
The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration ... The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration zone and in groundwater was analyzed. The result shows that the contaminant of groundwater comes from the leaching of petroleum in the soil horizon of aeration zone through precipitation, and the quick flow of groundwater makes the convection dominate themigration of contaminant. So movement of groundwater controls the distribution of petroleum contaminant, which is consistent with the direction of ground flow. Building a groundwater closure zone in Hougao is an effective method to stop the contaminated groundwater flowing toward the water supply source of Dawu. The petroleum contaminant can be effectively reduced through using the aeration, biological and oxidation technologies. 展开更多
关键词 Groundwater source Dawu area Petroleum pollution Groundwater closure zone aeration biological and oxidation technology
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Analysis of Soil Water Dynamics in a Tropical Rain Forest Soil (Arinic lixisol), Abeokuta, Nigeria
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作者 Sobowale Adeyinka Adewumi Johnson Kayode +1 位作者 Ogunniranye Gabriel Bayo Sajo Opeyemi Samuel 《Journal of Agricultural Science and Technology(A)》 2014年第6期494-503,共10页
Soil water dynamics in the dominant lwo soil series (Arinic lixisol) were evaluated at the Federal University of Agriculture, Alabata, Abeokuta, Nigeria. Field capacity, infiltration and water retention characterist... Soil water dynamics in the dominant lwo soil series (Arinic lixisol) were evaluated at the Federal University of Agriculture, Alabata, Abeokuta, Nigeria. Field capacity, infiltration and water retention characteristics were evaluated in situ for a period of 161 d in the dry season for two root zone depths. Results show that the Iwo soil series has a field capacity ranging from 2.6%-5.5% at 0-45 cm and 45-90 cm root zone depths, respectively. The soil is quick draining with high infiltration rate and very poor water retention capacity confirming that the soil will require a short irrigation interval of about 2-3 d since available water for plant growth in predominantly sandy soils ranges between 2%-8%. Based on the foregoing, sprinkler irrigation is best suited for the lwo soil series, it should, however, be noted that the water application rate must be less than the infiltration rate of the soil in order to prevent surface ponding and runoff. A multivariate model relating soil moisture content with soil moisture tension and soil temperature calibrated within the study had very low model accuracy of 56% and 45% for the two root zone depths, respectively, implying the need for further studies. 展开更多
关键词 Soil water INFILTRATION water retention soil tension IRRIGATION root zone depth.
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Recent movement changes of main fault zones in the Sichuan-Yunnan region and their relevance to seismic activity 被引量:4
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作者 LIU Xia MA Jin +3 位作者 DU XueSong ZHU Shuang LI LaYue SUN DongYing 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第6期1267-1282,共16页
The Wenchuan earthquake occurred near the "triple junction" linking the Bayan Har block, the South China block, and the Sichuan-Yunnan rhombic block, and its influences on the surrounding blocks and the main... The Wenchuan earthquake occurred near the "triple junction" linking the Bayan Har block, the South China block, and the Sichuan-Yunnan rhombic block, and its influences on the surrounding blocks and the main fault zones in the Sichuan-Yunnan region, i.e., the block boundary zone, cannot be ignored. In this paper, changes of movement and stress of the fault zones before and after a strong earthquake were simulated based on the GPS repetition survey results recently obtained during 1999–2007, 2009–2011, and 2011–2013 with a two-dimensional finite-element contact model and the "block- loading" method. The results show that, before the Wenchuan earthquake, the movement of the Longmenshan fault zone was very slow and its compressive stress accumulated rapidly; after the Wenchuan earthquake, movements toward the E-SSE direction of the Bayan Har, southwestern Yunnan, and rhombic blocks were enhanced, and the dextral and horizontal compressive speeds and annual accumulative compressive stress of the Longmenshan fault zone increased markedly by factors of 4.5, 2.1, and 2.5, respectively. The southern Xianshuihe, Anninghe, Zemuhe, Daliangshan, and Lijiang-Xiaojinhe fault zones accumulated compressive stress rapidly, forming enhanced compressive stress zones along a NE strike crossing the central part of the Sichuan-Yunnan region. The tensional movement of the Xianshuihe fault zone was enhanced and the slip movement in the central part of the zone was reversed in a short time. The changes are tightly related to the medium-intensity earthquakes that occurred during the same period in this region, revealing that the spatial migration of seismic activity is related to changes of movement of the blocks. 展开更多
关键词 Sichuan-Yunnan region Wenchuan earthquake Tectonic block Finite-element analysis Fault
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Spatial patterns and determinants of Moraceae richness in China 被引量:1
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作者 Hua-Feng Wang Xiaoting Xu +6 位作者 Xia-Lan Cheng Yunpeng Liu Ao Luo Tong Lyu Wen-Long Wang Mir Muhammad Nizamani Zhiheng Wang 《Journal of Plant Ecology》 SCIE CSCD 2022年第6期1142-1153,共12页
Understanding large-scale patterns of biodiversity and their drivers remains central in ecology.Many hypotheses have been proposed,including hydrothermal dynamic hypothesis,tropical niche conservatism hypothesis,Janze... Understanding large-scale patterns of biodiversity and their drivers remains central in ecology.Many hypotheses have been proposed,including hydrothermal dynamic hypothesis,tropical niche conservatism hypothesis,Janzen’s hypothesis and a combination model containing energy,water,seasonality and habitat heterogeneity.Yet,their relative contributions to groups with different lifeforms and range sizes remain controversial,which have limited our ability to understand the general mechanisms underlying species richness patterns.Here we evaluated how lifeforms and species range sizes influenced the relative contributions of these three hypotheses to species richness patterns of a tropical family Moraceae.The distribution data of Moraceae species at a spatial resolution of 50 km×50 km and their lifeforms(i.e.shrubs,small trees and large trees)were compiled.The species richness patterns were estimated for the entire family,different life forms and species with different range sizes separately.The effects of environmental variables on species richness were analyzed,and relative contributions of different hypotheses were evaluated across life forms and species range size groups.The species richness patterns were consistent across different species groups and the species richness was the highest in Sichuan,Guangzhou and Hainan provinces,making these provinces the hotspots of this family.Climate seasonality is the primary factor in determining richness variation of Moraceae.The best combination model gave the largest explanatory power for Moraceae species richness across each group of range size and life forms followed by the hydrothermal dynamic hypothesis,Janzen’s hypothesis and tropical niche conservatism hypothesis.All these models has a large shared effects but a low independent effect(<5%),except rare species.These findings suggest unique patterns and mechanisms underlying rare species richness and provide a theoretical basis for protection of the Moraceae species in China. 展开更多
关键词 hydrothermal dynamic hypothesis tropical niche conservatism hypothesis Janzen’s hypothesis MORACEAE environmental factor China
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Selectivity in feeding preferences and ranging patterns in spider monkeys Ateles geoffroyi yucatanensis of northeastern Yucatan peninsula, Mexico
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作者 Carmen SCHERBAUM Alejandro ESTRADA 《Current Zoology》 SCIE CAS CSCD 2013年第1期125-134,共10页
The spider monkey, a fruit specialist and important seed dispersal agent in the Neotropics, is an endangered primate due to habitat loss, hunting and the pet trade. Spider monkeys have been the subject of a few studie... The spider monkey, a fruit specialist and important seed dispersal agent in the Neotropics, is an endangered primate due to habitat loss, hunting and the pet trade. Spider monkeys have been the subject of a few studies in Central and South Ame- rica, but little is known about the diet and ranging for this primate in southern Mexico. Here we report the results of a six-month long study (October 2010 to March 2011) of the feeding preferences and ranging patterns of the Yucatan spider monkey Ateles geoffroyi yucatanensis living in the "Ya'ax'che" reserve by the Caribbean coast in northeast Yucatan peninsula. Focal animal and scan sampling as well as GPS tracking were used to document spider monkey feeding behavior, location of food trees and ranging in the reserve. The spider monkeys used 36 species of plants (94% trees; n = 432) and six non tree morphospecies as a source of food. Six tree species accounted for 〉~80% of total feeding time and for 74% of all trees used. Fruits accounted for 59% of total feeding time, followed by leaves (35%), palm piths (5%) and other plant parts (1%). Total range used by the monkeys was esti- mated at 43% of semievergreen rainforest habitat available (ca 40ha). Range use was not random with segments showing light, moderate and heavy use; the use of different areas of their range varied monthly and was closely linked to the spatial dispersion of the trees used for food [Current Zoology 59 (1): 125-134, 2013]. 展开更多
关键词 PRIMATES FRUGIVORY NEOTROPICS CONSERVATION Seed dispersal
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Holographic Duals of Quark Gluon Plasmas with Unquenched Flavors
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作者 Francesco Bigazzi Aldo Cotrone +2 位作者 Javier Mas Daniel Mayerson Javier Tarrio 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第3期364-386,共23页
We review the construction of gravitational solutions holographically dual to N=1 quiver gauge theories with dynamical flavor multiplets.We focus on the D3-D7 construction and consider the finite temperature,finite qu... We review the construction of gravitational solutions holographically dual to N=1 quiver gauge theories with dynamical flavor multiplets.We focus on the D3-D7 construction and consider the finite temperature,finite quark chemical potential case where there is a charged black hole in the dual solution.Discussed physical outputs of the model include its thermodynamics (with susceptibilities) and general hydrodynamic properties. 展开更多
关键词 AdS/CFT correspondence quark-gluon plasma flavor physics finite baryon density
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