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稀源管理在超深超稠原油开采中的应用 被引量:1
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作者 闵航 《内蒙古石油化工》 CAS 2009年第2期144-145,共2页
塔河油田十二区是中国石化在西部增储上产的主阵地,具有超深、超稠等特点,所产原油具有高粘度、高含蜡、高含硫化氢等特点,原油粘度在7.8-140万毫帕.秒(50摄氏度),开采难度极大。全部油井均采用掺稀油降粘开采,目前做为稀油的稀源随着... 塔河油田十二区是中国石化在西部增储上产的主阵地,具有超深、超稠等特点,所产原油具有高粘度、高含蜡、高含硫化氢等特点,原油粘度在7.8-140万毫帕.秒(50摄氏度),开采难度极大。全部油井均采用掺稀油降粘开采,目前做为稀油的稀源随着稠油上产需要,已日趋紧张,现场实践表明,一方面通过优化掺稀量、油田化学降粘实验等采油工艺技术可节约或替代目前稀源,另一方面现场管理在稠油开采中特别是对于稀源管理所发挥的重要作用,在目前塔河油田十二区超深超稠原油开采中具有同样的重要性。 展开更多
关键词 稀源 管理 稠油
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Investigation on the Rare and Endangered Plants in the Fenhe Source
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作者 郭春燕 岳建英 +5 位作者 李晋川 王文英 Chun-yan Jian-ying Jin-chuan Wen-ying 《Agricultural Science & Technology》 CAS 2010年第5期112-116,共5页
Fouty-eight species of rare and endanged plants in the Fenhe Source,belong to 21 families 37 genera.There were 1specie of national second-class protected plant and 3 species of national third-class plants;4 species of... Fouty-eight species of rare and endanged plants in the Fenhe Source,belong to 21 families 37 genera.There were 1specie of national second-class protected plant and 3 species of national third-class plants;4 species of first-class protected plants,6 species of second-class protected plants and 14 species of third-class protected plants in Shanxi Province.On the basis of analyzing the endanged reasons,related protection countemeasures were put forward in this article. 展开更多
关键词 Fenhe Source Rare and endanged plants Flora Conservation countemeasura
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Sources of rare earth elements REE+Y(REY)in Bayili Coal Mine from Wensu County of Xinjiang,China 被引量:2
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作者 Jian-qiang XUE Jian-xin LIU +4 位作者 De-zhi HUANG Wei-jian ZHOU Chun-ming LIU Yu-sen CAO Chuang-hua CAO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第10期3105-3115,共11页
By analyses on the trace elements of coals,host-rocks and wall-rocks,this study aims to trace the sources and evaluate the utilization prospects of REE+Y(REY)in coals from Bayili Coal Mine(Wensu,Xinjiang,China).The di... By analyses on the trace elements of coals,host-rocks and wall-rocks,this study aims to trace the sources and evaluate the utilization prospects of REE+Y(REY)in coals from Bayili Coal Mine(Wensu,Xinjiang,China).The distribution patterns of REY in the coals are divided into two groups,flat-type and heavy REE-enrichment type(H-type).The REY of the former was mainly from the gneisses of the basement of the coal-bearing basin,and that of the later was partly from hydrothermal solution.The host-rocks show two types of REY patterns,middle REE-enrichment type(M-type)and H-type,which are due to the injection of REY from acid terrestrial water and hydrothermal solution,respectively.Almost all the coal samples are plotted into the promising area on the diagram of percentage of critical elements(REY_(def,rel))vs ratio of sum of critical elements to the sum of excessive elements(C_(outl))and half of the coal samples have high contents of Ga closing to the cut-off grade of Ga deposit as by-product,which indicate that the REY and Ga in Bayili Coal Mine are of utilization prospects as by-product. 展开更多
关键词 source rare earth elements distribution pattern COAL Wensu County(Xinjiang)
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More than Target 6.3: A Systems Approach to Rethinking Sustainable Development Goals in a Resource-Scarce World 被引量:3
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作者 Qiong Zhang Christine Prouty +1 位作者 Julie B. Zimmerman James R. Mihelcic 《Engineering》 SCIE EI 2016年第4期481-489,共9页
The 2030 Agenda for Sustainable Development outlines 17 individual Sustainable Development Goals (SDGs) that guide the needs of practice for many professional disciplines around the world, including engineering, res... The 2030 Agenda for Sustainable Development outlines 17 individual Sustainable Development Goals (SDGs) that guide the needs of practice for many professional disciplines around the world, including engineering, research, policy, and development. The SDGs represent commitments to reduce poverty, hunger, ill health, gender inequality, environmental degradation, and lack of access to clean water and sanitation. If a typical reductionist approach is employed to address and optimize individual goals, it may lead to a failure in technological, policy, or managerial development interventions through unin- tended consequences in other goals. This study uses a systems approach to understand the fundamental dynamics between the SDGs in order to identify potential synergies and antagonisms. A conceptual system model was constructed to illustrate the causal relationships between SDGs, examine system structures using generic system archetypes, and identify leverage points to effectively influence intentional and minimize unintentional changes in the system. The structure of interactions among the SDGs reflects three archetypes of system behavior: Reinforcing Growth, Limits to Growth, and Growth and Underinvestment. The leverage points identified from the conceptual model are gender equality, sustainable management of water and sanitation, alternative resources, sustainable livelihood standards, and global partnerships. Such a conceptual system analysis of SDGs can enhance the likelihood that the development community will broaden its understanding of the potential synergistic benefits of their projects on resource management, environmental sustainability, and climate change. By linking the interactions and feedbacks of those projects with economic gains, women's empowerment, and educational equality, stakeholders can recognize holistic improvements that can be made to the quality of life of many of the world's poor. 展开更多
关键词 Systems thinking SanitationEnvironmental protection GenderResource recovery Causal loop diagram Sustainability
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Using Geochemistry of Rare Earth Elements to Indicate Sediment Provenance of Sand Ridges in Southwestern Yellow Sea 被引量:5
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作者 LI Lei SU Jinbao +1 位作者 RAO Wenbo WANG Yigang 《Chinese Geographical Science》 SCIE CSCD 2017年第1期63-77,共15页
The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncer... The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element(REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters((La/Yb)_N,(La/Sm)_N and(Gd/Yb)_N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, dEu,(La/Yb)_N,(Gd/Yb)_N and(La/Sm)_N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of(La/Yb)_N,(La/Sm)_N and La contents differing from those of the Chinese and Korean river sediments. 展开更多
关键词 rare earth elements(REEs) sediment provenance radial sand ridges(RSRs) potential sources Yellow Sea
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Change in Sediment Provenance Near the Current Estuary of Yellow River Since the Holocene Transgression 被引量:3
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作者 SONG Sheng FENG Xiuli +3 位作者 LI Guogang LIU Xiao XIAO Xiao FENG Li 《Journal of Ocean University of China》 SCIE CAS CSCD 2018年第3期535-544,共10页
Sedimentary sequence and sediment provenance are important factors when it comes to the studies on marine sedimentation. This paper studies grain size distribution, lithological characteristics, major and rare earth e... Sedimentary sequence and sediment provenance are important factors when it comes to the studies on marine sedimentation. This paper studies grain size distribution, lithological characteristics, major and rare earth elemental compositions, micropaleontological features and ^(14)C ages in order to examine sedimentary sequence and sediment provenance of the core BH6 drilled at the mouth of the Yellow River in Bohai Sea. According to the grain size and the micropaleontological compositions, 4 sedimentary units have been identified. Unit 1(0–8.08 mbsf) is of the delta sedimentary facies, Unit 2(8.08–12.08 mbsf) is of the neritic shelf facies, Unit 3(12.08–23.85 mbsf) is of near-estuary beach-tidal facies, and Unit 4(23.85 mbsf–) is of the continental lake facies. The deposits from Unit 1 to Unit 3 have been found to be marine strata formed after the Holocene transgression at about 10 ka BP, while Unit 4 is continental lacustrine deposit formed before 10 ka BP. The provenances of core BH6 sediments show properties of the continental crust and vary in different sedimentary periods. For Unit 4 sediments, the source regions are dispersed while the main provenance is not clear, although the parent rock characteristics of a few samples are similar to the Luanhe River sediments. For Unit 3, sediments at 21.1–23.85 mbsf have been mainly transported from the Liaohe River, while sediments above 21.1 mbsf are mainly from the Yellow River and partially from the Liaohe River. For Unit 2, the sediments have been mainly transported from the Yellow River, with a small amount from other rivers. For Unit 1, the provenance is mainly the Yellow River catchment. These results help in better understanding the evolution of the Yellow River Delta. 展开更多
关键词 Yellow River Estuary Holocene transgression rare earth element PROVENANCE
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Screening Programs for Cervical Cancer: Investigation "SWOT" in Calabria 被引量:1
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作者 Giuseppe Andrea De Biase Caterina Azzarito +7 位作者 Carmela Bianchi Amalia De Luca Domenico Gulla Salvatore Lopresti Dario Macchione Domenica Mignuolo Liliana Rizzo Filomena Zappia 《Journal of Pharmacy and Pharmacology》 2016年第6期279-282,共4页
(Screening programs for cervical cancer: a "SWOT" investigation in the Calabria Region)---The low adherence to screening programs for cervical cancer in Calabria, was analyzed by performing a SWOT analysis with c... (Screening programs for cervical cancer: a "SWOT" investigation in the Calabria Region)---The low adherence to screening programs for cervical cancer in Calabria, was analyzed by performing a SWOT analysis with concerned health professionals. The survey shows that screening organized in Calabria is active and well regulated, the human and financial resources are scarce and the healthcare management has paid little attention to the prevention of women's cancers. In the perspective of a necessary improvement of the regional system of screening, it would be appropriate to enable promotion strategies and more effective communication, overcoming possible cultural factors hindering. 展开更多
关键词 PREVENTION uterus cancer swot analysis
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Underdetermined Blind Source Separation of Adjacent Satellite Interference Based on Sparseness 被引量:10
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作者 Chengjie Li Lidong Zhu Zhongqiang Luo 《China Communications》 SCIE CSCD 2017年第4期140-149,共10页
The problem of underdetermined blind source separation of adjacent satellite interference is proposed in this paper. Density Clustering algorithm(DC-algorithm) presented in this article is different from traditional m... The problem of underdetermined blind source separation of adjacent satellite interference is proposed in this paper. Density Clustering algorithm(DC-algorithm) presented in this article is different from traditional methods. Sparseness representation has been applied in underdetermined blind signal source separation. However, some difficulties have not been considered, such as the number of sources is unknown or the mixed matrix is ill-conditioned. In order to find out the number of the mixed signals, Short Time Fourier Transform(STFT) is employed to segment received mixtures. Then, we formulate the blind source signal as cluster problem. Furthermore, we construct Cost Function Pair and Decision Coordinate System by using density clustering. At the end of this paper, we discuss the performance of the proposed method and verify the novel method based on several simulations. We verify the proposed method on numerical experiments with real signal transmission, which demonstrates the validity of the proposed method. 展开更多
关键词 adjacent satellite interference Short Time Fourier Transform Decision Coordinate System real signal transmission
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Water Resource and Regional Economic Growth Study Based on Panel Data
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作者 Xilin Zhang 《Journal of Earth Science and Engineering》 2014年第10期627-631,共5页
Empirical analysis to the relationship between water resource scarcity degree and economic growth were done by building relationship model between water resource scarcity degree and regional economic growth with provi... Empirical analysis to the relationship between water resource scarcity degree and economic growth were done by building relationship model between water resource scarcity degree and regional economic growth with provincial panel data of 30 provinces during 2000-2009. The analysis results show that, in water resource scarcity regions, the shortage of water resource is the key factor of restricting economic development. In order to alleviate the shortage of water resource and meet the needs of economic development to water resource, it is necessary to speed up the establishment of water right trading market and finally achieve the goal of water-saving and regulation of water resource by economic leverage. The specific countermeasures include: first, comprehensively considering the endowment difference of water resource when carrying out industrial planning and layout; second, speeding up the establishment of water right trading market and revising water-saving incentive mechanism; third, increasing fiscal transfer payment ability to the provinces of outputting water resource; fourth, strengthening industrial guidance, making moderate industrial transfer and population movement; fifth, paying attention to science, technology and education investment, to improve utilization efficiency of water resource. 展开更多
关键词 Shortage of water resource regional economic growth panel data endowment of water resource.
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Uplink user allocation scheme in cognitive coexistent cellular network
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作者 刘婷婷 Wang Mao +2 位作者 Shu Feng Wang Jianxin Pan Ziyu 《High Technology Letters》 EI CAS 2014年第4期376-382,共7页
In order to address spectrum resource scarcity in traditional cellular networks,television(TV)white space is considered as a potential solution to offload a portion of network traffic and enlarge network capacity.This... In order to address spectrum resource scarcity in traditional cellular networks,television(TV)white space is considered as a potential solution to offload a portion of network traffic and enlarge network capacity.This paper describes a cognitive cellular network which allocates low geometry users to the TV white space based on a proportional fair criterion.An uplink user allocation scheme is proposed and the validity of the proposed scheme is established by simulation of the cellular network usage in conjunction with the TV white space.The simulation results show clear improvements in both the user and the system performance with the cognitive coexistent cellular network compared with the traditional cellular network,and that the performance of the proposed user allocation scheme is superior to other user allocation schemes. 展开更多
关键词 cognitive radio TV white space spectrum efficiency system throughput fractional frequency reuse
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Sparse constrained encoding multi-source full waveform inversion method based on K-SVD dictionary learning 被引量:1
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作者 Guo Yun-dong Huang Jian-Ping +3 位作者 Cui Chao LI Zhen-Chun LI Qing-Yang Wei Wei 《Applied Geophysics》 SCIE CSCD 2020年第1期111-123,169,共14页
Full waveform inversion(FWI)is an extremely important velocity-model-building method.However,it involves a large amount of calculation,which hindsers its practical application.The multi-source technology can reduce th... Full waveform inversion(FWI)is an extremely important velocity-model-building method.However,it involves a large amount of calculation,which hindsers its practical application.The multi-source technology can reduce the number of forward modeling shots during the inversion process,thereby improving the efficiency.However,it introduces crossnoise problems.In this paper,we propose a sparse constrained encoding multi-source FWI method based on K-SVD dictionary learning.The phase encoding technology is introduced to reduce crosstalk noise,whereas the K-SVD dictionary learning method is used to obtain the basis of the transformation according to the characteristics of the inversion results.The multiscale inversion method is adopted to further enhance the stability of FWI.Finally,the synthetic subsag model and the Marmousi model are set to test the effectiveness of the newly proposed method.Analysis of the results suggest the following:(1)The new method can effectively reduce the computational complexity of FWI while ensuring inversion accuracy and stability;(2)The proposed method can be combined with the time-domain multi-scale FWI strategy flexibly to further avoid the local minimum and to improve the stability of inversion,which is of significant importance for the inversion of the complex model. 展开更多
关键词 K-SVD dictionary sparsity constraint polarity encoding MULTI-SOURCE full waveform inversion
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Resource Evaluation of Heavy Rare Earth Derived from the Spent Gd203 Burnable Poison in LWRs
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作者 Yuki Tanoue Tsugio Yokoyama Masaki Ozawa 《Journal of Energy and Power Engineering》 2016年第4期237-241,共5页
A burnup calculation has been performed to evaluate heavy rare earth (terbium--Tb, dysprosium--Dy) production in spent gadolinium oxide (Gd203) installed as a BP (burnable poison). Each amount of Tb and Dy produ... A burnup calculation has been performed to evaluate heavy rare earth (terbium--Tb, dysprosium--Dy) production in spent gadolinium oxide (Gd203) installed as a BP (burnable poison). Each amount of Tb and Dy production derived from the BP has been about 30-40 times larger than those created in FP (fission products). Required cooling time to achieve exemption level on radioactivity concentration produced Tb and Dy derived from the BP are much shorter (BP-Tb: 7.9y, BP-Dy: 〈 0.1y) than those created in FP (FP-Tb: 3,616y, FP-Dy: 6.9y). However, the BP is mixed homogeneously with UO2 pellet in current nuclear fuel system of LWRs (light water reactors), and hence mixing of FP cannot be not avoided. In such a mixture case, the required cooling time of recovered Tb will become 2,653y and that of recovered Dy be 4.8y. For this reason, recovered Tb is unlikely to be resource for utilization, while recovered Dy must be the resource provided the precise separation from the other FP. 展开更多
关键词 Bumable poison heavy rare earth Tb DY fission products Adv.-ORIENT Cycle.
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Ash-and-Slag Wastes of Energy Sector as Raw Material for Production of Rare-Earth Metals and Alumina
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作者 Irina Blayda Larisa Slysarenko +1 位作者 Tatiana Vasyleva Zinesh Abisheva 《Journal of Environmental Science and Engineering(A)》 2012年第5期704-713,共10页
The results to develop a complex technology of co-extraction of germanium and gallium from the ash-and-slag wastes of coal combustion in Ukraine were presented. Based on the study of phase changes occurring in initial... The results to develop a complex technology of co-extraction of germanium and gallium from the ash-and-slag wastes of coal combustion in Ukraine were presented. Based on the study of phase changes occurring in initial raw materials as a result of its processing, it was proposed to carry out a preliminary enrichment of the raw materials in order to produce secondary sublimates. Their further processing involves a combination of leaching soluble material with distillation of germanium in the form of tetrachloride. The resulting acidic solutions are trended to the gallium extraction. Optimum conditions of carrying out of processes are recommended.The chemical and phase composition of the resulting dump products and solutions have been defined. On the basis of it ways of their processing for the purpose of reception of alumina and building materials are recommended. 展开更多
关键词 GALLIUM germanium ALUMINA fly ash leaching restorative burning.
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Embedded FPGA Simulator for Wireless Sensor Network Design
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作者 Nasreddine Nadim Boizard Jean Louis Christophe Escriba Foumiols Jean Yves 《Journal of Energy and Power Engineering》 2012年第6期984-992,共9页
The design, manufacture and deployment of embedded systems become increasingly complex and multidisciplinary process. Before the steps of manufacturing and deployment, a simulation and validation phase is necessary. I... The design, manufacture and deployment of embedded systems become increasingly complex and multidisciplinary process. Before the steps of manufacturing and deployment, a simulation and validation phase is necessary. In this paper, a WSN (wireless sensors network) emulator, implemented on a FPGA, is described by: describing some models as examples, how multiple simulations can be done when the device was configured and programmed once, and how results from the behavioral emulator can be extracted. The diversity of applications and the typically scarce node resources set very tight constraints to WSN. It is not possible to fulfill all requirements with a general purpose WSN, for which reason the rapid development of application specific WSNs is preferred. A new emulator for the design, simulation, and evaluation of WSNs, implemented on a very dense FPGA (field programmable gate arrays), is presented, exploring the parallelism and his resources to do a very rapid simulation ofa WSN for long periods, and without overloading memory by the intermediate data. 展开更多
关键词 WSN FPGA VHDL BER PER.
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Geochemistry of Neoproterozoic mixosedimentite in northern Anhui and its geological significance
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作者 SUN Linhua GUI Herong CHEN Song 《Global Geology》 2010年第3期128-134,共7页
Major oxides,as well as trace elements (including rare earth elements) compositions have been analyzed for the mixosedimentites from Neoproterozoic Jiayuan Formation in northern Anhui,China. The results show that the ... Major oxides,as well as trace elements (including rare earth elements) compositions have been analyzed for the mixosedimentites from Neoproterozoic Jiayuan Formation in northern Anhui,China. The results show that the concentrations of elements are closely related to the relative proportions of carbonates and terrigenous detritus (varying from 2/3 to 1/9 based on petrographic study). The ratios between some immobile elements (e.g. La,Th,Zr and Sc) are constant and then can be used as tracers for the discrimination of provenance and tectonic setting of terrigenous detritus. The results indicate that the terrigenous detritus mainly came from the felsic volcanics related to continental arc,with minor contribution from the old basement. Combined with recent research progresses,these mixosedimentites imply that the Neoproterozoic sedimentation in northern Anhui was probably taken place in a back arc basin during the convergence of Rodinia super continent between 1.0 and 0.8 Ga. 展开更多
关键词 PROVENANCE tectonic setting mixosedimentites NEOPROTEROZOIC northern Anhui
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塔河超深层中质油对稠油降粘的适应性 被引量:10
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作者 李业 敬加强 +1 位作者 陈朝刚 代科敏 《油气储运》 CAS 2012年第7期504-506,509,共4页
针对塔河油田超深层油藏地质特点和原油性质,以TK1073、TH10227及TH12312井稠油和4种塔河稀油为研究对象,采用流变学方法,测试分析原油的流变特性及粘温特性,评价不同塔河稠油分别掺入不同量的一厂DK4、一联、1#和2#混合油4种塔河稀油... 针对塔河油田超深层油藏地质特点和原油性质,以TK1073、TH10227及TH12312井稠油和4种塔河稀油为研究对象,采用流变学方法,测试分析原油的流变特性及粘温特性,评价不同塔河稠油分别掺入不同量的一厂DK4、一联、1#和2#混合油4种塔河稀油的降粘效果,探讨轻质油及混配中质油对塔河稠油降粘的适应性,以达到扩大稀油源、节约轻质油的目的。研究结果表明:TK1073与TH12312井稠油属超稠油,TH10227井稠油属特稠油,其生产与集输必须采取掺稀等降粘措施;一厂DK4轻质油、一联中质油及1#混合中质油对塔河稠油掺稀降粘具有较好的适应性,而2#混合中质油则相对较差。实际应用证实了室内研究结论的可靠性。 展开更多
关键词 塔河稠油 中质油 轻质油 稠油掺降粘
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Interactions Between Exogenous Rare Earth Elements and Phosphorus Leaching in Packed Soil Columns 被引量:2
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作者 LIANG Tao SONG Wen-Chong +2 位作者 WANG Ling-Qing P. J. A. KLEINMAN CAO Hong-Ying 《Pedosphere》 SCIE CAS CSCD 2010年第5期616-622,共7页
Rare earth elements (REEs) increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus (P) from heavily fertilized soils. The vertical transport character... Rare earth elements (REEs) increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus (P) from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum (La), neodymium (Nd), samarium (Sin), and cerium (Ce), were investigated with addition of exogenous REEs at various doses to packed soil columns (20 cm deep). Vertical transfers of REEs and P were relatively small, with transport depths less than 6 cm for most REEs and P. Export of applied REEs in leachate accounted for less that 5% of inputs. The addition of Ce, Nd and Sm to soil columns significantly decreased concentrations of extractable soil P up to a depth of 4 cm, with soil P concentrations unaffected at depths 〉 4 cm. In general, REEs had little effect on the vertical leaching of P in packed soil columns. 展开更多
关键词 extractable soil P MANURE MOBILITY TRANSLOCATION vertical transport
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Source number estimation and separation algorithms of underdetermined blind separation 被引量:2
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作者 YANG ZuYuan TAN BeiHai ZHOU GuoXu ZHANG JinLong 《Science in China(Series F)》 2008年第10期1623-1632,共10页
Recently,sparse component analysis (SCA) has become a hot spot in BSS re-search. Instead of independent component analysis (ICA),SCA can be used to solve underdetermined mixture efficiently. Two-step approach (TSA) is... Recently,sparse component analysis (SCA) has become a hot spot in BSS re-search. Instead of independent component analysis (ICA),SCA can be used to solve underdetermined mixture efficiently. Two-step approach (TSA) is one of the typical methods to solve SCA based BSS problems. It estimates the mixing matrix before the separation of the sources. K-means clustering is often used to estimate the mixing matrix. It relies on the prior knowledge of the source number strongly. However,the estimation of the source number is an obstacle. In this paper,a fuzzy clustering method is proposed to estimate the source number and mixing matrix simultaneously. After that,the sources are recovered by the shortest path method (SPM). Simulations show the availability and robustness of the proposed method. 展开更多
关键词 sparse representation blind source separation underdetermined mixing model fuzzy clustering mixing matrix
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Rapid earthquake focal mechanism inversion using high-rate GPS velometers in sparse network 被引量:3
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作者 GUO AiZhi NI SiDao +2 位作者 CHEN WeiWen Jeffrey T.FREYMUELLER SHEN ZhiChao 《Science China Earth Sciences》 SCIE EI CAS CSCD 2015年第11期1970-1981,1,共12页
In this study, we demonstrate an approach for inverting earthquake source parameters based on high-rate global positioning system (GPS) velocity seismograms. The velocity records obtained from single-station GPS vel... In this study, we demonstrate an approach for inverting earthquake source parameters based on high-rate global positioning system (GPS) velocity seismograms. The velocity records obtained from single-station GPS velocity solutions with broadcast ephemeris are used directly for earthquake source parameter inversion using the Cut and Paste method, without requiring conversion of the velocity records into displacement records. Taking the E1 Mayor-Cucapah earthquake as an example, GPS velocity records from 10 stations with reasonable azimuthal coverage provide earthquake source parameters very close to those from the Global centroid moment tensor (Global CMT) solution. In sparse network tests, robust source parameters with acceptable bias can be achieved with as few as three stations. When the number of stations is reduced to two, the bias in rake angle becomes appreciable, but the magnitude and strike estimations are still robust. The results of this study demonstrate that rapid and reliable estimation of earthquake source parameters can be obtained from GPS velocity data. These parameters could be used for early earthquake warning and shake map construction, because such GPS velocity records can be obtained in real time. 展开更多
关键词 high-rate GPS velometer GPS velocity determination CAP method earthquake source parameters sparse network
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Geochemical characteristics and geological significance of Cretaceous phonotephrite from the Mid-Pacific Mountains 被引量:1
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作者 Shuangshuang CHEN Jiaqi LIU 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第6期745-764,共20页
Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic r... Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic rocks are mainly phonotephrite with a porphyritic texture. Phenocrysts are mainly composed of Ca-rich plagioclase, clinopyroxene and nepheline.These volcanic rocks are significantly rich in large-ion lithophile and light rare earth elements, without obvious Eu anomalies(δEu=0.99–1.03), and with relatively enriched^(87) Sr/^(86) Sr(0.703829–0.704313) and^(143) Nd/^(144) Nd isotopic ratios(0.512857–0.512871), suggesting that they have similar but more enriched features than the OIB magmatic source. These volcanic rocks may originate from relatively deep magma source with the existence of spinel-garnet Iherzolites, and have undergone partial melting at a low degree of 1–3%. In addition, The residual Nb-Ta minerals(such as sphene, rutile, perovskite) may remain in the mantle source, and the magma components have undergone metasomatism by carbonate melt/fluid or alkali-rich fluid, causing high contents of incompatible elements and significant loss of Nb, Ta and Ti in these volcanic rocks. There are many similarities between the phonotephrites in the Mid-Pacific Mountain and the volcanic rocks in the Line Islands based on the tectonic settings and the geochemical characteristics. We thus speculate that Site 313 volcanic rocks in the Mid-Pacific Mountain is most likely to be a continuation of the Line Islands. 展开更多
关键词 Phonotephrite OIB-type mantle source Carbonatite metasomatism Line Islands Mid-Pacific Mountain
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