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On electro-acoustic characteristics of a marine broadband sparker for seismic exploration
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作者 Jing LI Kai LIU +3 位作者 Liancheng ZHANG Chenguang LIU Yanliang PEI Baohua LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第3期760-771,共12页
The construction of major marine infrastructure projects and the exploration and development of deep-sea mineral resources require fine imaging of seabed strata and structures.The highresolution marine seismic explora... The construction of major marine infrastructure projects and the exploration and development of deep-sea mineral resources require fine imaging of seabed strata and structures.The highresolution marine seismic exploration based on a high broadband sparker source is an important approach to reveal seabed stratum and reservoir structure,and identify geohazard.To optimize the performance of sparker seismic source,we investigated the electro-acoustic characteristics of spark discharge under conditions of different charging voltages and electrode numbers.Results show that the sound source level increased with the increase of the charging voltage,whereas the main frequency decreased when the charging voltage increases.In addition,it was found that the charging capacitance had more obvious influence on the main frequency than the sound source level did.Although the load energy decreased with increasing electrode number,the sound source level still increased but the main frequency decreased.Meanwhile,the primary to bubble(P/B)ratio increased with the increase of the electrode number.To gain a deeper insight into the electro-acoustic characteristics,we investigate the relationship between sound source level and power peak,from which a good correlation was observed.A more practical statistical analysis on the rise rate of current was processed,and a perfect logarithmic function was derived.Furthermore,we found that the main frequency was most possibly subjected to the electrical energy,especially the charging energy per electrode.The results indicate that the charging energy per electrode less than 10 J could increase the main frequency to above 300 Hz.At last,the main frequency could be reduced to 20 Hz when the charging energy of a single-electrode discharge was enhanced to over 4 kJ.This study shall be helpful in developing a sparker seismic source and improving the performance for marine engineering exploration and geohazard assessment. 展开更多
关键词 high-resolution marine seismic exploration sparker seismic source sound source level main frequency electro-acoustic characteristics
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Analysis Method and Application of Multiple Antiquities Sources in the Shahejie Formation of the Paleogene in the Southern Bohai Sea
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作者 Jianmin Zhang Honglin Yue Xijie Wang 《Open Journal of Applied Sciences》 2024年第4期1070-1079,共10页
B Oilfield is the most representative mid to deep oil field in the Bohai Sea, with the main oil bearing intervals being the upper and middle Shahejie-3 sections of the Paleogene Shahejie Formation. Through the develop... B Oilfield is the most representative mid to deep oil field in the Bohai Sea, with the main oil bearing intervals being the upper and middle Shahejie-3 sections of the Paleogene Shahejie Formation. Through the development of ancient landforms, characterization of material source channels, analysis of missing heavy mineral sources, and seismic reflection characteristics of multiple material source missing, the material sources of the middle and upper Shahejie-3 sections are analyzed. During the sedimentation period of the II oil formation in the middle section of the Shasan Formation, the study area was mainly dominated by the Kendong Uplift source rocks;During the sedimentation period of the I oil formation in the middle section of the Shasan Formation, there were three material sources in the study area, namely the Kendong Uplift, the Laibei Low Uplift, and the Weibei Uplift. The Kendong Uplift was the main material source, followed by the Laibei Low Uplift;During the sedimentation period of the Upper Shasan Formation, the study area still had three sources of material supply simultaneously. At this time, the Laibei Low Uplift was the main source area, while the Kendong Uplift and Weibei Uplift had a relatively small supply capacity for the study area. In the analysis of archaeological sources, the distribution characteristics of the sedimentary system in the third section of the Shahejie Formation have been clarified, providing a research basis for the later development and adjustment of the oilfield. 展开更多
关键词 Paleogeomorphology Characterization of source Channels Tracing of Heavy Minerals Seismic Reflection characteristics Sedimentary Systems
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Large-scale characteristics of thermokarst lakes across the source area of the Yellow River on the Qinghai-Tibetan Plateau
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作者 LIU Wen-hui ZHOU Guang-hao +5 位作者 LIU Hai-rui LI Qing-peng XIE Chang-wei LI Qing ZHAO Jian-yun ZHANG Qi 《Journal of Mountain Science》 SCIE CSCD 2023年第6期1589-1604,共16页
As significant evidence of permafrost degradation,thermokarst lakes play an important role in the permafrost regions by regulating hydrology,ecology,and biogeochemistry.In the Sources Area of the Yellow River(SAYR),pe... As significant evidence of permafrost degradation,thermokarst lakes play an important role in the permafrost regions by regulating hydrology,ecology,and biogeochemistry.In the Sources Area of the Yellow River(SAYR),permafrost degradation has accelerated since the 1980s,and numerous thermokarst lakes have been discovered.In this paper,we use Sentinel-2 images to extract thermokarst lake boundaries and perform a regional-scale study on their geometry across the permafrost region in the SAYR.We also explored the spatiotemporal variations and potential drivers from the perspectives of the permafrost,climate,terrain and vegetation conditions.The results showed that there were 47,518 thermokarst lakes in 2021 with a total area of 190.22×106 m^(2),with an average size of 4,003.3 m^(2).The 44,928 ponds(≤10,000 m^(2))predominated the whole lake number(94.1%)but contributed to a small portion of the total lake area(28.8%).With 2,590 features(5.9%),small-sized(10,000 to 100,000 m^(2))and large-sized lakes(>100,000 m^(2))constituted up to 71.2%of the total lake area.Thermokarst lakes developed more significantly in warm permafrost regions than in cold permafrost areas;74.1%of lakes with a total area of 119.6×106 m^(2)(62.9%),were distributed in warm permafrost regions.Most thermokarst lakes were likely to develop within the elevation range of 4,500~4,800 m,on flat terrain(slope<10°),on SE and S aspects and in alpine meadow areas.The thermokarst lakes in the study region experienced significant shrinkage between 1990 and 2021,characterized by obvious lake drainage;the lake numbers decreased by 5418(56.1%),with a decreasing area of 58.63×106 m^(2)(49.0%).This shrinkage of the thermokarst lake area was attributable mainly to the intensified degradation of rich-ice permafrost thawing arising from continued climate warming,despite the wetting climatic trend. 展开更多
关键词 Thermokarst lake Spatial characteristic Influencing factor source area of the Yellow River
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Control of Interior Sources on Time-Bound Characteristics of Mineralization in Southwest Yangtze Massif 被引量:1
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作者 Yu Bingsong Department of Geology and Mineral Resources, China University of Geosciences, Beijing 100083 《Journal of Earth Science》 SCIE CAS CSCD 1999年第1期84-89,共6页
Strata bound ore deposits of Au, Ag, Hg, Sb, As, Sn, Pb and Zn in southwest Yangtze massif are concentrated in Cambrian, Devonian, Upper Permian to Lower Triassic and rarely in other horizons, showing a strong time ... Strata bound ore deposits of Au, Ag, Hg, Sb, As, Sn, Pb and Zn in southwest Yangtze massif are concentrated in Cambrian, Devonian, Upper Permian to Lower Triassic and rarely in other horizons, showing a strong time bound feature. The metallogenic elements are highly enriched in these host strata and limited in other horizons. Isotope researches indicate that the metallogenic elements in the ore deposits mainly come from the host strata. The studies of trace elements in the host mudstone show lower w (Th)/ w (Sc), w (Th)/ w (U) ratios, higher mafic elements (such as Cr, Ni, Co) mass fractions than the average values of the same kind of rocks in the upper crust and the research area. The chondrite normalized REE patterns of mudstone in the host strata are quite different from the common mudstones and shales with relatively steep HREE slopes (relatively high w (Tb) n/ w (Yb) n ratios, between 1.48 and 2.00) and no or slightly negative Eu anomalies (high δ (Eu) ratios, between 0.79 and 0.89). The NASC normalized REE patterns of siliceous rocks in the host strata show the HREE enrichment (the w (La) n/ w (Yb) n ratios are less than 1), a little Eu positive anomalies and Ce depletion with high abundances of As, Se, Sb and Ba elements, which shows the hydrothermal deposit features. The NASC normalized REE patterns of the mudstone in the host strata are very similar to those of the hydrothermal siliceous rocks and to those of the tuffs and basalts except the higher total REE mass fractions. All of these geochemical characteristics suggest the existence of interior sources pouring into basin when the host strata were deposited. The research of basin evolution also indicates that the host strata were deposited in the pulling apart periods. It can be realized from these facts that the degree of enrichment and deficiency of the elements in the normal depositional strata is very limited, and it is only the particular horizons corresponding to the particular periods of the earth ’s evolution that can be the significant source beds because only in these unusual horizons can be highly enriched metallogenic elements. The interior sources corresponding to the pulling apart of basin evolution may be the main cause to make the mineralization of the strata bound ore deposits in southwest Yangtze massif take on time bound characteristics. 展开更多
关键词 interior source time bound characteristic MINERALIZATION southwest Yangtze massif.
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Characteristics of groundwater and urban emergency water sources optimazation in Luoyang,China 被引量:3
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作者 YANG Liu ZHANG Ying-ping +2 位作者 WEN Xue-ru PEI Li-xin LIU Bing 《Journal of Groundwater Science and Engineering》 2020年第3期298-304,共7页
The construction of emergency water sources is the material basis for ensuring urban water safety,and it is also an inherent requirement for maintaining social stability and development.The hydrogeological characteris... The construction of emergency water sources is the material basis for ensuring urban water safety,and it is also an inherent requirement for maintaining social stability and development.The hydrogeological characteristics of groundwater in Luoyang City from the aspects of the division of groundwater aquifer groups,water yield property and groundwater dynamics were described in this paper.Two emergency water sources were selected on basis of comprehensively considering groundwater resources and ecological environmental effects,groundwater quality and exploitation technology,etc.Then it further analysed the aquifer types,water yield properties and groundwater recharge,runoff and discharge conditions of the two emergency water sources,and evaluate the groundwater resources quantity of the water sources.The results are that the shallow underground aquifer in Luoyang City is thick,coarse,and stable in lithology and thickness.The two water sources enjoy good exploitation potential and can be used as backup water sources to supply water in the event of a water source crisis. 展开更多
关键词 Groundwater characteristics Emergency water sources Exploitation potentiality Urban water supply risk Luoyang City
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Distributional characteristics and sources of elements in soil from typical area of Pearl River Delta economic zone, Guangdong Province, China 被引量:1
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作者 Lei Dou Shu-Zhen Shen Hai-Yan Du 《Chinese Journal Of Geochemistry》 EI CAS CSCD 2015年第3期299-310,共12页
Dongguan City, located in the Pearl River Delta economic zone of China, is famous for its rapid developing township-enterprises in the past 30 years. A total of 759 composite soil samples, including 606 surface soil s... Dongguan City, located in the Pearl River Delta economic zone of China, is famous for its rapid developing township-enterprises in the past 30 years. A total of 759 composite soil samples, including 606 surface soil samples and 153 deep soil samples, have been collected in the city. These samples have been analyzed for 13elements(Al, As, Cu, Cd, Co, Cr, Fe, Hg, Mn, Ni, Pb, Si,and Zn) and other parameters(p H values and organic matter) to evaluate the influence of anthropic activities on the soil environmental quality and to identify the spatial distribution of heavy metals and their possible sources. The results indicate that the average concentrations of heavy metals in soil were significantly lower than the threshold of the second grade of the Soil Environment Quality Standard in China(GB15618-1995) and the soil environmental quality in this area is comparatively good. But in comparison with local soil geochemical baseline values, As,Cd, Cu, Hg, Pb, and Zn have accumulated remarkably.Specifically, the average concentrations of As, Cd, Cu, and Hg in the small part samples of the west plain and central areas are higher than the national second-grade quality standard, indicating some level of contamination. Multivariate and geostatistical methods have been applied to differentiate the influences of natural processes and human activities on the concentration of heavy metals in surface soils in the study area. Cluster and factor analyses result in the grouping of Al, As, Cr, Cu, Fe, Ni, and Si into factor F1; Co, Mn, Pb, and Zn into F2; and Cd and Hg into F3.The spatial pattern of the three factors may be well demonstrated by geostatistical analysis. It is shown that the first factor could be considered as a natural source controlled by parent material. The second factor could be referred to as ‘‘industrial and traffic pollution sources' '. The source of the third factor is mainly controlled by long-term anthropic activities, including agricultural activities, fossil fuel consumption, and atmospheric deposition. 展开更多
关键词 珠江三角洲经济区 元素分布特征 土壤样品 土壤重金属含量 典型区 广东省 土壤环境质量 交通污染源
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Alternate operation characteristics of a solar-ground source heat pump system 被引量:4
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作者 杨卫波 陈振乾 施明恒 《Journal of Southeast University(English Edition)》 EI CAS 2010年第2期327-332,共6页
In order to investigate the alternate operation characteristics of a solar-ground source heat pump system(SGSHPS),various alternate operation modes are put forward and defined.A two-dimensional mathematical model wi... In order to investigate the alternate operation characteristics of a solar-ground source heat pump system(SGSHPS),various alternate operation modes are put forward and defined.A two-dimensional mathematical model with freezing/melting phase changes is developed for the heat transfer analysis of the soil.Based on the numerical solution of the model,the variation trends of underground soil temperature of the SGSHPS operated in various alternate operation modes are discussed.The results indicate that,for the day-night and short-time interval alternate operation modes without solar energy,the operation time fraction of a solar heat source should be confined to from 50% to 58% when operated in an alternate period of 24 h.Meanwhile,the disadvantages of a natural resumption of soil temperature can be overcome effectively by solar energy filling,and an optimal operation effect can be achieved by integrating the mode of solar energy filling with other alternate modes.In addition,the accuracy of the presented model is verified by the experimental data of borehole wall temperatures.The conclusions can provide a reference for the optimization operation of the SGSHPS. 展开更多
关键词 solar-ground source heat pump alternate operation characteristics numerical simulation experimental validation
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Metabolic Characteristics and Functional Diversity of Carbon Source in Microflora of Ponds with Recirculating Aquaculture System 被引量:2
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作者 李谷 宋景华 +3 位作者 李晓莉 张世羊 陶玲 张春雪 《Agricultural Science & Technology》 CAS 2014年第2期278-282,299,共6页
With Biolog Eco microplate, metabolic characteristics and functional diver-sity of carbon source in microflora of ponds were researched based on recitculating ponds and control ponds in order to explore effects of eco... With Biolog Eco microplate, metabolic characteristics and functional diver-sity of carbon source in microflora of ponds were researched based on recitculating ponds and control ponds in order to explore effects of eco-adjustments on microflo-ra in ponds. The results indicate that total number of bacterium, microbial metabolism activity, and diversity index in P7, P8, P1 and P2 kept higher, fol owed by P3, P4, P5 and P6. The utilization rate of microbes on sugars achieved the highest (31.0%-48.7%), fol owed by carboxylic acid (13.4%-18.0%), amino acid (10.1%-20.5%), polymers (9.4%-17.0%), biopolymer (5.7%-9.7%) and phenol (4.95%-7.50%). Principal component analysis divided microflora in different ponds, suggesting that microbial community has varied carbon source characteristics and nitrogen-containing compound and biopolymer metabolisms are most affected. 展开更多
关键词 Aquaculture pond MICROBE -Metabolic characteristics of carbon source Functional diversity
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Behavior Characteristics of Tourists and Detailed Classification of Tourist Source Market in Liuxihe National Forest Park
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作者 陈丽丽 章家恩 《Journal of Landscape Research》 2011年第1期87-90,共4页
On the basis of questionnaires and field investigation,behavior characteristics of tourists in Liuxihe National Forest Park were analyzed,and the results showed that tourists in the study area mainly come from the Pea... On the basis of questionnaires and field investigation,behavior characteristics of tourists in Liuxihe National Forest Park were analyzed,and the results showed that tourists in the study area mainly come from the Pearl River Delta for sightseeing,mostly 21-45 years old,with higher revisit rate but less residence time.And meanwhile,key tourist source markets of Liuxihe National Forest Park were classified on the basis of spatial distance features,social and economic features,and behavior characteristics of tourists,specifically,The Pearl River Delta Sightseeing Tourist Market,The Pearl River Delta Vacationing Tourist Market,The Pearl River Delta Business Tourist Market,and The Pearl River Delta Special-interest Tourist Market.Moreover,corresponding development strategies were proposed according to actual conditions of each market. 展开更多
关键词 Liuxihe NATIONAL FOREST Part Behavior characteristics of TOURISTS TOURIST sourcE MARKET
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THEORETICAL INVESTIGATION ON HEAT TRANSFER CHARACTERISTICS WITH ROTATING THERMAL SOURCE
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作者 夏文庆 朱春玲 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2004年第1期43-46,共4页
By reduction to one dimensional, periodic as well as rotating pulse heat sources, investigation on heat transfer characteristics with rotating body is carried out. Similar to the fluid flow, a new set of dimensionless... By reduction to one dimensional, periodic as well as rotating pulse heat sources, investigation on heat transfer characteristics with rotating body is carried out. Similar to the fluid flow, a new set of dimensionless numbers, namely quasi-Peclet numbers Pe 1, Pe 2 and Biot number Bi composed of angular velocity ω , thermophysical parameter, and geometry size are proposed, and applied to the dimensionless equations. Simulation result shows that it plays a decisive role in the process of the heat transfer. However, more important is that the numerical simulation depicts the difference between microcosmic and macroscopic structures of the temperature distribution, and reveals the influence of the relative relation of the dimensionless criterion numbers upon heat transfer characteristics. 展开更多
关键词 heat transfer characteristics rotating heat source SIMULATION dimensionless criterion numbers
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Distribution Characteristics of Effective Source Rocks and Their Control on Hydrocarbon Accumulation: A Case Study from the Dongying Sag, Eastern China 被引量:32
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作者 ZHUGuangyou JINQiang +3 位作者 ZHANGShuichang DAIJinxing ZHANGLinye LIJian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第6期1275-1288,共14页
The exploration conducted in the Bohai Bay basin, eastern China has demonstrated that the abundant petroleum resources have close affinities to the hydrocarbon kitchen with rich organic matter. A number of oil-generat... The exploration conducted in the Bohai Bay basin, eastern China has demonstrated that the abundant petroleum resources have close affinities to the hydrocarbon kitchen with rich organic matter. A number of oil-generating associations with various characteristics of organic geochemistry and assemblages of multiple reservoir facies are developed due to the multi-center sedimentation, multi-source supply and multi-cycle evolution of filling, which have resulted in the formation of multiple oil and gas accumulation zones of various layers and trap styles. Among them the Paleogene Shahejie Formation is the most important hydrocarbon accumulation combination in the Dongying sag. Heretofore, its proved reserve has reached nearly 1.8×109t, which accounts for more than 90% of the total proved reserves of the Dongying sag. Based on previous studies, more than 600 source rock samples and 186 crude oil samples of the Shahejie Formation, collected from 30 oilfields, have been treated with organic geochemical testing. By combining the sedimentary sequence characteristics and geochemical analysis results, the source rocks of the Shahejie Formation can be divided into three genetic types, i.e. the saline lake facies (the upper ES4, brackish water deep lake facies (the lower ES3) and fresh-water lake facies (the middle ES3), which correspond to the under-filling, balanced-filling and over-filling lake types respectively and represent the three most essential genetic models for source rocks of non-marine fault basins in China. Based on a thorough oil-source correlation, the source rocks of the saline lake and brackish deep lake facies are determined to be the most contributive source rocks in the Dongying sag. Furthermore, by probing into the accumulation of organic matter and hydrocarbon migration pattern, it can be inferred that the hydrocarbons, generated from source rocks of the saline lake facies with relatively low maturity, have mainly accumulated in the uplifted parts of the basin's margin via lateral migration and the reservoirs are dominated by the buried hill and stratigraphic types, while hydrocarbons generated from source rocks of the brackish lake facies are mainly distributed in the basin's center via vertical migration and characterized by forming lithologic reservoirs. Also, the reservoirs located in the transitional belts have complex types and mostly controlled by faults, characterized by block (structural-lithologic) reservoirs, and the crude oils mainly come from source beds of Es31 and Es42 respectively. 展开更多
关键词 source rocks association characteristics fluctuation lacustrine facies sedimentation heterogeneity Dongyingsag
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Variations of precipitation characteristics during the period 1960–2014 in the Source Region of the Yellow River,China 被引量:7
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作者 Mudassar IQBAL WEN Jun +2 位作者 WANG Shaoping TIAN Hui Muhammad ADNAN 《Journal of Arid Land》 SCIE CSCD 2018年第3期388-401,共14页
Precipitation, a natural feature of weather systems in the Earth, is vitally important for the environment of any region. Under global climate change condition, the characteristics of precipitation have changed as a c... Precipitation, a natural feature of weather systems in the Earth, is vitally important for the environment of any region. Under global climate change condition, the characteristics of precipitation have changed as a consequence of enhanced global hydrological cycle. The source region of the Yellow River(SRYR), locating within the Qinghai-Tibet Plateau, is sensitive to the global climate change due to its complex orography and fragile ecosystem. To understand the precipitation characteristics and its impacts on the environment in the region, we studied the characteristics of rainy days and precipitation amount of different precipitation classes, such as light(0–5 and 5–10 mm), moderate(10–15, 15–20 and 20–25 mm) and heavy(≥25 mm) rains by analyzing the precipitation data of typical meteorological stations in the SRYR during the period 1961–2014, as well as the trends of persistent rainfall events and drought events. Results showed that annual average precipitation in this area had a non-significant(P〉0.05) increasing trend, and 82.5% of the precipitation occurred from May to September. Rainy days of the 0–5 mm precipitation class significantly decreased, whereas the rainy days of 5–10, 10–15, and 20–25 mm precipitation classes increased and that of ≥25 mm precipitation class decreased insignificantly. The persistent rainfall events of 1-or 2-day and more than 2-day showed an increasing trend, with the 1-or 2-day events being more frequent. Meanwhile, the number of short drought periods(≤10 days) increased while long drought periods(〉10 days) decreased. Since the 0–5 mm precipitation class had a huge impact on the grasslands productivity; the 5–10, 10–15, and 20–25 mm precipitation classes had positive effects on vegetation which rely on the deep soil water through moving nutrients and water into the root zone of these vegetation or through the plant-microbe interactions; the ≥25 mm precipitation class contributed to the floods; and more persistent rainfall events and fewer long drought events inferred positive effects on agriculture. Thus, these results indicate grassland degradation, less risk of floods, and the upgrading impact of climate change on agriculture. This study may provide scientific knowledge for policymakers to sustain the eco-environmental resources in the SYSR. 展开更多
关键词 precipitation characteristics climate change ECOSYSTEM water resources VEGETATION source region of theYellow River
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Variation characteristics of aquifer parameters induced by groundwater source heat pump operation under variable flow 被引量:5
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作者 王松庆 张旭 《Journal of Central South University》 SCIE EI CAS 2011年第4期1272-1277,共6页
The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of buildin... The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of building air conditioning load were considered.The results,compared with the constant flow operation,indicate that the influence on the variations of porosity,hydraulic conductivity and confined water head is decreased by 48%,51% and 71%,respectively,under variable flow operation.The security of variable flow operation is superior to that of constant flow.It is also concluded that the climate region and function of the buildings are primary factors which affect the suitability of variable flow operation in GWSHP. 展开更多
关键词 groundwater source heat pump variation characteristic aquifer parameter variable flow
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Geochemical Characteristics and Sedimentary Control of Pinghu Formation(Eocene)Coal-bearing Source Rocks in Xihu Depression,East China Sea Basin 被引量:3
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作者 SHEN Yulin QIN Yong +5 位作者 CUI Min XIE Guoliang GUO Yinghai QU Zhenghui YANG Tianyang YANG Liu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2021年第1期91-104,共14页
Coal-bearing source rocks of the Pinghu Formation in the Xihu Depression comprise an important material basis of oil and gas resources in the East China Sea Basin.Based on drilling core observation results combined wi... Coal-bearing source rocks of the Pinghu Formation in the Xihu Depression comprise an important material basis of oil and gas resources in the East China Sea Basin.Based on drilling core observation results combined with the analysis and test results of macerals,trace/rare earth elements,and rock pyrolysis,the geochemical characteristics and sedimentary control of coal-bearing source rocks formation are discussed in a high-frequency sequence framework.The results indicate that the macerals composition of the coal-bearing source rocks of the Eocene Pinghu Formation in the Xihu Depression is dominated by vitrinite,with low-medium abundance of exinite and almost no inertinite.The coals and carbonaceous mudstones display higher amounts of total organic carbon(TOC)(14.90%-65.10%),S1+S2(39.24-136.52 mg/g),and IH(191-310 HC/g TOC)respectively,as compared to the mudstones.Organic matter is plotted in typeⅢkerogens and partially in typeⅡ;it is mainly in the low maturity stage.The trace elements results imply that the samples were deposited in a weakly reducing to weakly oxidizing environment and were occasionally affected by seawater.The coal-bearing source rocks were deposited in a relatively oxygen-containing environment.The coal-bearing source rocks development is jointly controlled by the coal accumulation environment,the water conditions affected by ocean currents in offshore basins in China,oxidation-reduction cycles of aqueous media and paleoclimate evolution in a high-frequency sequence framework. 展开更多
关键词 geochemical characteristics coal-bearing source rock high-frequency sequence Pinghu Formation Xihu Depression
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Study on the Source Characteristics of Downhole Airgun with Different Excitation Environments 被引量:2
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作者 Yang Wei Wang Baoshan +3 位作者 Liu Zhengyi Yang Jun Li Xiaobin Chen Yong 《Earthquake Research in China》 CSCD 2016年第3期342-354,共13页
The measurement of underground medium variation using a repeated artificial source has gradually become an important goal to pursue. In recent years,we have developed and improved a technology system with large capaci... The measurement of underground medium variation using a repeated artificial source has gradually become an important goal to pursue. In recent years,we have developed and improved a technology system with large capacity airguns excited in land reservoirs by transplanting marine seismic exploration technology. The excitation effect has a close relationship to airgun capacity,water environment,and excitation conditions. In view that large capacity airgun must be excited without a water environment,we expand the system to use in downhole. Based on the BHS-2200 LL downhole airgun with a capacity of250in3,this paper carries out a comparative analysis on the characteristics of an airgun source excited in 0. 2m- and 5. 0m-diameter wells,and the results show that:( 1) The dominant frequency of the airgun signal excited in a 5. 0m well is mainly from 10 Hz to40Hz,lower than that in a 0. 2m well,and the larger body of water is good for bubble oscillation.( 2) In terms of exciting energy,the signal excited in a 5. 0m well has stronger energy than in a 0. 2m well,with a difference of 1 order in magnitude,and the signal can be detected up to 9km excited in a 5. 0m well with a single shot.( 3) The airgun signal has good repeatability in both excitation wells. The downhole airgun excitation technology system has potential application in dynamic monitoring near a fault zone with a small scale range, exploration of oil and mineral resources, and modern urban geophysical environment. 展开更多
关键词 Artificial source Downhole airgun Excitation environment Seismic source characteristics REPEATABILITY
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Distribution characteristics and source of BTEX in groundwater in Guangzhou,Guangdong Province,P.R.China 被引量:1
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作者 LIU Chun-yan SUN Ji-chao +2 位作者 JING Ji-hong ZHANG Ying GUO Wei-xuan 《Journal of Groundwater Science and Engineering》 2016年第3期238-246,共9页
In order to find out the distribution characteristics of BTEX in groundwater, which include Benzene, Toluene, Ethylbenzene, p-Xylene, m-Xylene, and o-Xylene, 82 groups of groundwater samples and 10 surface water sampl... In order to find out the distribution characteristics of BTEX in groundwater, which include Benzene, Toluene, Ethylbenzene, p-Xylene, m-Xylene, and o-Xylene, 82 groups of groundwater samples and 10 surface water samples collected from Guangzhou in Guangdong during 2005 to 2008 were tested by gas chromatography and mass spectrum(GC/MS). The result showed that the BTEX concentration in groundwater does not exceed the standard. The detection rate of BTEX is 14.63% in groundwater, and the total BTEX concentration is lower than 9.5 μg/L. Of 6 kinds of BTEX, toluene had the highest detection rate(12.20%) and detection value(9.5 μg/L), which was followed by Benzene, with the detection rate of 3.65%, and detection value of 4.9 μg/L respectively; most of samples with BTEX are distributed in Huangpu district, Baiyun district, Huadu district and other industrialized areas; this spatial distribution and urban distribution have obvious consistency. With economic development, plant expansion and population growth led to a large amount of waste water discharge, and infrastructure construction is lagging behind, indicating that rapid urbanization is a major driving force of BTEX in groundwater, and through the analysis of a typical area, it is found that benzene system surface water infiltration was an important source of BTEX in groundwater of Guangzhou. 展开更多
关键词 GUANGZHOU GROUNDWATER BTEX Distribution characteristics source to investigate
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Heavy Minerals and Geochemical Characteristics of Sandstones as Indices of Provenance and Source Area Tectonics of the Ogwashi-Asaba Formation, Niger Delta Basin 被引量:1
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作者 O. Innocent Ejeh I. Anthony Akpoborie A. A. Israel Etobro 《Open Journal of Geology》 2015年第8期562-576,共15页
Heavy mineral petrographic and geochemical compositions (major and trace/rare earth elements)?of sandstones obtained from the Oligocene-Miocene Ogwashi-Asaba Formation, Niger Delta were studied to determine their prov... Heavy mineral petrographic and geochemical compositions (major and trace/rare earth elements)?of sandstones obtained from the Oligocene-Miocene Ogwashi-Asaba Formation, Niger Delta were studied to determine their provenance, source area weathering conditions and tectonic setting. The heavy mineral suite (opaque minerals, zircon, tourmaline, and rutile) revealed that the sandstones are mineralogically mature and implied rapid disintegration and chemical decomposition of sediments mostly of recycled orogen. The sandstones were geochemically classified as Fe-sand and partly quartz arenitic. Chemical Index of Alteration and Chemical Index of Weathering values of 89.92% and 91.87% respectively suggest that the source region was predominantly felsic and was subjected to intense chemical weathering probably under tropical palaeoclimatic conditions with abundant rainfall that enhanced sediment recycling. Major element concentration discriminant plots also indicated that the sediments were derived from mixed sources (granitic, gneissic or recycled orogen) under passive margin setting. Chondrite normalized plot of the rare earth element pattern is marked by light rare earth element enrichment and negative Eu anomalies, interpreted to mean that provenance was mainly continental crustal rocks. Trace elemental ratios that are provenance diagnostic (La/Sc, Th/Sc, Cr/Th, La/Co, Th/Co, Th/Cr, Eu/Eu*, and Eu*) all point to sediments derived from felsic source and upper continental crust. The mixed provenance of the sandstones can be traced to the southwestern and southeastern Basement Complex (consisting of granites, gneisses, etc.) and sediments derived from the adjacent sedimentary basins (Anambra and Benue Trough). 展开更多
关键词 PROVENANCE source Area TECTONICS Heavy Minerals Geochemical characteristics SANDSTONES Ogwashi-Asaba Formation Niger Delta BASIN
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Characteristics of Resistance Triggering of a Pulsed Vacuum Arc Ion Source 被引量:1
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作者 蓝朝晖 龙继东 +4 位作者 郑乐 董攀 杨振 王韬 李杰 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第9期84-87,共4页
Triggering scheme is a significant factor that may influence the process of vacuum arc initiation. In this work, the characteristics of resistance triggering of a pulsed vacuum arc ion source are investigated and comp... Triggering scheme is a significant factor that may influence the process of vacuum arc initiation. In this work, the characteristics of resistance triggering of a pulsed vacuum arc ion source are investigated and compared with the independent pulse generator triggering. The results show that although the resistance triggering method is capable of triggering a vacuum arc ion source by properly choosing the resistance and electric parameters, it inevitably increases the rise time of the arc current. A high speed multiframe camera is used to reveal the transition process o~ arc initiation during one shot. From the images it is conjectured that the lower voltage between the cathode and the anode may be the reason that leads to the lower transition speed of discharge at the moment of arc initiation. 展开更多
关键词 In characteristics of Resistance Triggering of a Pulsed Vacuum Arc Ion source ARC
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Characteristics of Rearranged Hopanes of Hydrocarbon Source Rocks in Saline Sedimentary Environment: A Case Study of the Songliao Basin 被引量:1
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作者 JIANG Lian ZHANG Min +1 位作者 LI Hongbo XIAO Qilin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第6期2269-2270,共2页
The Songliao Basin, one of the biggest continental petroliferous basins in eastern China, is a Mesozoic- Cenozoic fault-depressed and fault-subsided basin developed on the Hercynian fold basement. Generally, rearrange... The Songliao Basin, one of the biggest continental petroliferous basins in eastern China, is a Mesozoic- Cenozoic fault-depressed and fault-subsided basin developed on the Hercynian fold basement. Generally, rearranged hopanes are considered to be formed by clay- mediated acidic catalysis under oxic or suboxic environment, whereas high abundance of rearranged hopanes were found in hydrocarbon source rocks and crude oils that are derived from salty environment in the Songliao Basin. This phenomenon rarely happens all over the world. 展开更多
关键词 BA characteristics of Rearranged Hopanes of Hydrocarbon source Rocks in Saline Sedimentary Environment
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Biological Characteristics of Carex brunnescens for Sand Fixation in the Source Region of the Yellow River 被引量:1
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作者 康建军 赵明 +3 位作者 马和 张洋东 刘冬皓 童胜利 《Agricultural Science & Technology》 CAS 2017年第9期1716-1722,1725,共8页
Carex brunnescens, a pioneer plant that has an excellent ability to fix sand in the source region of the Yellow River (Maqu), plays an important role in maintaining the ecosystem stability of alpine grassland in Maq... Carex brunnescens, a pioneer plant that has an excellent ability to fix sand in the source region of the Yellow River (Maqu), plays an important role in maintaining the ecosystem stability of alpine grassland in Maqu. In this study, the biological characteristics (phonological characters, the growth process of overground and underground organs, and the morphological characters of underground organs) of C. brunnescens were studied by a field observation experiment. The results showed that C. brunnescens had the characteristics of turning green earlier than other plants, a long growth period, and two flowering and fruiting cycles. The leaf width, length and number of a single plant, and the density, coverage and leaf density of community increased significantly from the leaf extension period to the fruit mature period and then tended to be stable in the withering period, while the plant height and leaf area of a single plant and the leaf area of community rose significantly at first and then decreased. Underground stems (horizontal and vertical stems) and roots of C. brunnescens could survive in sand at a depth of 0-60 cm. The number of middle roots (0.2-0.5 mm in diameter) was the largest in all soil layers (0-20, 20-40 and 40-60 cm), and the total length of fine roots (〈0.2 mm) were the maximum in the sand at a depth of 20-40 cm, while the total length of middle roots was the maximum in the sand layer at a depth of 0-20 cm. The length, fresh weight and dry weight of the main root, horizontal and vertical stems was the maximum in the sand layer at a depth of 10-30 cm and was the minimum in the sand layer at a depth of 40-50 cm. It is concluded that C. brunnescens can well adapt to the alpine sand habitat of Maqu, can be used as the constructive species for ecological restoration in the alpine desertified grassland of Maqu, and has good popularization and application prospects. 展开更多
关键词 source region of Yellow River (Maqu) Desertified grassland Carex brunnescens Biological characteristics for sand fixation
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