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Game theory attack pricing for mining pools in blockchain-based IoT
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作者 Yourong Chen Hao Chen +3 位作者 Zhenyu Xiong Banteng Liu Zhangquan Wang Meng Han 《Digital Communications and Networks》 SCIE CSCD 2024年第4期973-988,共16页
The malicious mining pool can sacrifice part of its revenue to employ the computing power of blockchain network.The employed computing power carries out the pool mining attacks on the attacked mining pool.To realize t... The malicious mining pool can sacrifice part of its revenue to employ the computing power of blockchain network.The employed computing power carries out the pool mining attacks on the attacked mining pool.To realize the win-win game between the malicious mining pool and the employee,the paper proposes an Employment Attack Pricing Algorithm(EAPA)of mining pools in blockchain based on game theory.In the EAPA,the paper uses mathematical formulas to express the revenue of malicious mining pools under the employment attack,the revenue increment of malicious mining pools,and the revenue of the employee.It establishes a game model between the malicious mining pool and the employee under the employment attack.Then,the paper proposes an optimal computing power price selection strategy of employment attack based on model derivation.In the strategy,the malicious mining pool analyzes the conditions for the employment attack,and uses the derivative method to find the optimal utilization value of computing power,employees analyze the conditions for accepting employment,and use the derivative method to find the optimal reward value of computing power.Finally,the strategy finds the optimal employment computing power price to realize Nash equilibrium between the malicious mining pool and the employee under the current computing power allocation.The simulation results show that the EAPA could find the employment computing power price that realizes the win-win game between the malicious mining pool and the employee.The EAPA also maximizes the unit computing power revenue of employment and the unit computing power revenue of honest mining in malicious mining pool at the same time.The EAPA outperforms the state-of-the-art methods such as SPSUCP,DPSACP,and FPSUCP. 展开更多
关键词 Game theory Blockchain PoW Mining pool Employment attack
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Effects of a decade of organic fertilizer substitution on vegetable yield and soil phosphorus pools, phosphatase activities, and the microbial community in a greenhouse vegetable production system 被引量:8
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作者 ZHANG Yin-jie GAO Wei +5 位作者 LUAN Hao-an TANG Ji-wei LI Ruo-nan LI Ming-yue ZHANG Huai-zhi HUANG Shao-wen 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2022年第7期2119-2133,共15页
Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated th... Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated the effects of longterm organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.A 10-year(2009–2019)field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools,phosphatase activities and the microbial community,and identify factors that regulate these soil P transformation characteristics.Four treatments included 100%chemical N fertilizer(4 CN),50%substitution of chemical N by manure(2 CN+2 MN),straw(2 CN+2 SN),and combined manure with straw(2 CN+1 MN+1 SN).Compared with the 4 CN treatment,organic substitution treatments increased celery and tomato yields by 6.9-13.8%and 8.6-18.1%,respectively,with the highest yields being in the 2 CN+1 MN+1 SN treatment.After 10 years of fertilization,organic substitution treatments reduced total P and inorganic P accumulation,increased the concentrations of available P,organic P,and microbial biomass P,and promoted phosphatase activities(alkaline and acid phosphomonoesterase,phosphodiesterase,and phytase)and microbial growth in comparison with the 4 CN treatment.Further,organic substitution treatments significantly increased soil C/P,and the partial least squares path model(PLS-PM)revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.Partial least squares(PLS)regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices. 展开更多
关键词 organic substitution management soil P pools phosphatase activity microbial community soil C/P PLS-PM
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Phase-field crystal simulation of evolution of liquid pools in grain boundary pre-melting regions 被引量:7
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作者 Xiao-lin TIAN Yu-hong ZHAO +3 位作者 Dun-wei PENG Qing-wei GUO Zhen GUO Hua HOU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第4期1175-1188,共14页
Pre-melting is a phenomenon that below the melting point the liquid-like structure appears at the grainboundary while the grain interior remains a crystal structure. The phase-field crystal method was employed to inve... Pre-melting is a phenomenon that below the melting point the liquid-like structure appears at the grainboundary while the grain interior remains a crystal structure. The phase-field crystal method was employed to investigate the early evolution of the liquid pools in pre-melting regions, mainly involving four structural transformations: solid-solid state → small droplet → large liquid pool → homogeneous liquid melting. The microscopic morphology and free energy variation with different average atomic densities demonstrate that the average atomic density is sensitive to the morphological characteristics of liquid pools. Both two-dimensional and three-dimensional simulation results show that the amplitude reduction of order parameters can promote the order-disorder transition of grain boundaries, causing pre-melting in the edge dislocation aggregation. The relationship between the average atomic density and the width of the liquid pools is verified from thermodynamics, which provides a prerequisite for the application of high-temperature strain in the later stage to some extent. 展开更多
关键词 phase-field crystal method pre-melting edge dislocations liquid pools
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Comparative studies on utilizing nitrogen capacity between two macroalgae Gracilaria tenuistipitata var. liui (rhodophyta) and Ulva pertusa (chlorophyta) II. Feedback controls of intracellular nitrogen pools on nitrogen uptake 被引量:5
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作者 LIU Jing Wen, DONG Shuang Lin (Aquaculture Research Laboratory, Ocean University of Qingdao, Qingdao 266003, China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2001年第3期323-327,共5页
The potential feedback by intracellular nitrogen pools on maximum N uptake (NH + 4) rate were determined for Gracilaria tenuistipitata var. liui and Ulva pertusa. The results of correlation matrix analyz... The potential feedback by intracellular nitrogen pools on maximum N uptake (NH + 4) rate were determined for Gracilaria tenuistipitata var. liui and Ulva pertusa. The results of correlation matrix analyzing showed that the surge uptake of ammonium seemed related to rapid changes in small intracellular pools of inorganic nitrogen or small peptide and amino acids rather than to changes in TN content of the macroalgae. The assimilation rates of nitrogen of U. pertusa and G. tenuistipitata increased slowly during N starvation and were mainly regulated by amino acids and some incorporation of amino acids into macromolecules. From ecological point of view, the fast growing and uptaking nutrient U. pertusa is more suitable to improve water quality in integrated shrimp culture ponds in which external nutrient supplies are usually high and constant during the culture period, while G. tenuistipitata var. liui is more suitable to be polycultured in a waters with intermittence supply of nutrients. 展开更多
关键词 nitrogen pools uptake kinetic MACROALGAE feedback
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Origin of Oils in“Subtle pools”in the Dongying Depression,Bohai Bay Basin, China 被引量:3
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作者 LI Sumei JIANG Zhengxue +2 位作者 LIU Keyu QIU Guiqiang GAO Yongjin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第1期184-196,共13页
Subtle traps or oil pools have become an important exploration play in the Dongying Depression, Bohai Bay Basin, east China. Despite recent successes in exploration, the formation mechanisms of subtle traps are still ... Subtle traps or oil pools have become an important exploration play in the Dongying Depression, Bohai Bay Basin, east China. Despite recent successes in exploration, the formation mechanisms of subtle traps are still not well understood. The majority of subtle oil pools in the Dongying Depression are developed in the middle interval of the Es3 Member of the Paleogene Shahejie Formation with the subtle traps being primarily of lenticular basin-floor turbidite sands encompassed in mudstones. Oil in the subtle traps was previously thought to have migrated directly from the surrounding source rocks of the same formation (Es3). Detailed geochemical investigation of 41 oils and 41 rock samples from the depression now indicates that the oils from the subtle traps cannot be correlated well with the surrounding Es3 source rocks, which are characterized by high Pr/ Ph (〉1), low Gammacerane/C30hopane, representing a freshwater lacustrine setting. In contrast the oils features low Pr/Ph (〈1) and relatively high Gammacerane content, showing a genetic affinity with the underlying Es4 source rocks, which also have the same qualities, indicating a brackish lacustrine setting. Oils in the Es3 subtle traps are probably derived from mixed sources with the contribution from the upper Es4 source rocks predominating. Therefore unconventional oil migration and accumulation mechanisms need to be invoked to explain the pooling of oils from the ES4 source rocks, which probably came through a thick low interval of the Es3 source rocks with no apparent structural or stratigraphic pathways. We suggest that the subtle oil migration pathway probably plays an important role here. This finding may have significant implications for future exploration and the remaining resource evaluation in the Dongying Depression. 展开更多
关键词 lenticular oil pools biomarkers oil-source rock correlation hydrocarbon migration and accumulation subtle oil migration pathway
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Effects of water and nitrogen addition on vegetation carbon pools in a semi-arid temperate steppe 被引量:2
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作者 Junqiang Jia Yunshe Dong +7 位作者 Yuchun Qi Qin Peng Xinchao Liu Liangjie Sun Shufang Guo Yunlong He Congcong Cao Zhongqing Yan 《Journal of Forestry Research》 SCIE CAS CSCD 2016年第3期621-629,共9页
Global change will lead to increases in regional precipitation and nitrogen(N) deposition in the semi-arid grasslands of northern China. We investigated the responses of vegetation carbon(C) pools to simulated pre... Global change will lead to increases in regional precipitation and nitrogen(N) deposition in the semi-arid grasslands of northern China. We investigated the responses of vegetation carbon(C) pools to simulated precipitation and N deposition increases through field experiments in a typical steppe in Inner Mongolia. The treatments included NH4NO3 addition at concentrations of 0(CK), 5(LN, low nitrogen), 10(middle nitrogen, MN), and 20(HN,high nitrogen)(g m^(-2)a^(-1)) with and without water. After three consecutive years of treatment, from 2010 to 2012,water addition did not significantly change the size of the total vegetation C pools, but it significantly decreased the ratio of root:shoot(R:S)(P = 0.05) relative to controls. By contrast, N addition significantly increased the total vegetation C pools. The C pools in the LN, MN and HN treatments increased by 22, 39 and 44 %, respectively. MN produced the largest effect among the N concentrations,although differences between N-added treatments were not significant(P ? 0.05). N addition significantly reduced the ratio of root:shoot(R:S)(P = 0.03). However, there were no significant interactive effects of water and N addition on the vegetation C pools. 展开更多
关键词 Vegetationprecipitation NitrogenTemperate steppecarbon pools Increasingaddition Interactive effect
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Soil carbon pools of six ecological regions of the United States 被引量:2
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作者 Amitava Chatterjee 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第5期1933-1938,共6页
Mineralisable soil organic carbon(SOC)pools vary with ecosystem type in response to changes in climate,vegetation and soil properties.Understanding the effect of climate and soil factors on SOC pools is critical for p... Mineralisable soil organic carbon(SOC)pools vary with ecosystem type in response to changes in climate,vegetation and soil properties.Understanding the effect of climate and soil factors on SOC pools is critical for predicting change over time.Surface soil samples from six ecoregions of the United States were analyzed for permanganate oxidizable C(KMnO4-C)and mineralizable C pools.Variations of SOC ranged from 7.9 mg g^-1(Florida site)to 325 mg g^-1(Hawaii site).Mineralisable C pools and KMnO4-C were highest in soils from the Hawaii site.Mean annual precipitation explains SOC and resistant C pool variations.Clay content was related to mineralisable active C pools and bacterial abundance.Mean annual precipitation and clay content are potential variables for predicting changes in SOC pools at large spatial scales. 展开更多
关键词 Permanganate oxidizable carbon(KMnO4-C) Resistant carbon pool Mean residence time Soil carbon pools United States
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A method for evaluating paleo hydrocarbon pools and predicting secondary reservoirs:a case study of the Sangonghe Formation in the Mosuowan area,Junggar Basin 被引量:2
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作者 Wei-Jiao Ma Yan-Zhao Wei Shi-Zhen Tao 《Petroleum Science》 SCIE CAS CSCD 2018年第2期252-269,共18页
Taking the Jurassic Sangonghe Formation in the Mosuowan-Mobei area of the Junggar Basin as an example, this paper provides a method that evaluates paleo hydrocarbon pools and predicts secondary reservoirs. Through Qua... Taking the Jurassic Sangonghe Formation in the Mosuowan-Mobei area of the Junggar Basin as an example, this paper provides a method that evaluates paleo hydrocarbon pools and predicts secondary reservoirs. Through Quantitative Grain Fluorescence (QGF) experiments, well-tie seismic correlation, and paleo structure analysis, the scale and distribution of paleo hydrocarbon pools in the study area are outlined. Combining current structural features and fault characteristics, the re-migration pathways of paleo oil and gas are depicted. Based on barrier conditions on the oil re-migration pathways and current reservoir distribution, we recognize three types of secondary reservoirs. By analyzing structural evolution and sand body-fault distribution, the major control factors of secondary reservoirs are specified and, consequently, favorable zones for secondary reservoirs are predicted. The results are mainly as follows. (1) In the primary accumulation period in the Cretaceous, paleo hydrocarbon pools were formed in the Sangonghe Formation of the Mosuowan uplift and their size and distribution were extensive and the exploration potential for secondary reservoirs should not be ignored. Besides, paleo reservoirs were also formed in the Mobei uplift, but just small scale. (2) In the adjustment period in the Neogene, traps were reshaped or destroyed and so were the paleo reservoirs, resulting in oil release. The released oil migrated linearly northward along the structural highs of the Mobei uplift and the Qianshao low-relief uplift and then formed secondary reservoirs when it met new traps. In this process, a structural ridge cooperated with sand bodies and faults, applying unobstructed pathways for oil and gas re-migration. (3) The secondary hydrocarbon pools are classified into three types: low-relief anticlinal type, lithologic pinch-out type and fault block type. The distribution of the first type is controlled by a residual low uplift in the north flank of the paleo-anticline. The second type is distributed in the lithologic pinch-out zones on the periphery of the inherited paleo uplift. The third type is controlled by fault zones of which the strikes are perpendicular to the hydrocarbon re-migration pathways. (4) Four favorable zones for secondary reservoirs are predicted: the low-relief structural zone of the north flank of the Mosuowan paleo-anticline, the fault barrier zone on the western flank of the Mobei uplift, the Qianshao low-relief uplift and the north area of the Mobei uplift that parallels the fault zone. The study above effectively supports the exploration of the Qianshao low-relief uplift, with commercial oil discovered in the Qianshaol well. Besides, the research process in this paper can also be applied to other basins to explore for secondary reservoirs. 展开更多
关键词 Junggar Basin Paleo hydrocarbon pools Hydrocarbon re-migration pathways Secondary reservoirs .Favorable zones
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Wintertime Stratospheric Anomalies-Part I: Warm Pools 被引量:2
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作者 Y.L.McHall 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1992年第3期299-310,共12页
The stratospheric worm pools, called the 4-day wave also, are mainly the temperature anomalies in the polar regions of winter hemisphere. It will be shown that their occurrence, propagation speed and specific structur... The stratospheric worm pools, called the 4-day wave also, are mainly the temperature anomalies in the polar regions of winter hemisphere. It will be shown that their occurrence, propagation speed and specific structure can be explained by the lower frequency coherent heating resulting from the wave interaction in the breaking layers of the stratosphere. Although their vertical phase slope is negligibly small, the warm pools cannot be considered as a barotropic anomaly. 展开更多
关键词 Wintertime Stratospheric Anomalies-Part I Warm pools
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Equality Testing for Soil Grid Unit Resolutions to Polygon Unit Scales with DNDC Modeling of Regional SOC Pools 被引量:2
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作者 YU Dongsheng PAN Yue +4 位作者 ZHANG Haidong WANG Xiyang NI Yunlong ZHANG Liming SHI Xue-zheng 《Chinese Geographical Science》 SCIE CSCD 2017年第4期552-568,共17页
Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of... Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of soil grid units at varying cell sizes was derived from soil polygon units at six map scales,namely,1:50 000(C5),1:200 000(D2),1:500 000(P5),1:1 000 000(N1),1:4 000 000(N4) and 1:14 000 000(N14),in the Taihu Region of China.Both soil unit formats were used for regional SOC pool simulation with a De Nitrification-DeC omposition(DNDC) process-based model,which spans the time period from 1982 to 2000 at the six map scales.Four indices,namely,soil type number(STN),area(AREA),average SOC density(ASOCD) and total SOC stocks(SOCS) of surface paddy soils that were simulated by the DNDC,were distinguished from all these soil polygon and grid units.Subjecting to the four index values(IV) from the parent polygon units,the variations in an index value(VIV,%) from the grid units were used to assess its dataset accuracy and redundancy,which reflects the uncertainty in the simulation of SOC pools.Optimal soil grid unit resolutions were generated and suggested for the DNDC simulation of regional SOC pools,matching their respective soil polygon unit map scales.With these optimal raster resolutions,the soil grid units datasets can have the same accuracy as their parent polygon units datasets without any redundancy,when VIV < 1% was assumed to be a criterion for all four indices.A quadratic curve regression model,namely,y = – 0.80 × 10^(–6)x^2 + 0.0228 x + 0.0211(R^2 = 0.9994,P < 0.05),and a power function model R? = 10.394?^(0.2153)(R^2 = 0.9759,P < 0.05) were revealed,which describe the relationship between the optimal soil grid unit resolution(y,km) and soil polygon unit map scale(1:10 000x),the ratio(R?,%) of the optimal soil grid size to average polygon patch size(?,km^2) and the ?,with the highest R^2 among different mathematical regressions,respectively.This knowledge may facilitate the grid partitioning of regions during the investigation and simulation of SOC pool dynamics at a certain map scale,and be referenced to other landscape polygon patches' mesh partition. 展开更多
关键词 soil organic carbon(SOC) soil grid unit resolutions soil polygon unit map scales DeNitrification-DeComposition(DNDC) model SOC pools
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Exploration Significance of Unconformity Structure on Subtle Pools
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作者 Kongyou Wu,Ming Zha,Jiangxiu Qu Faculty of Geo-Resource and Information,China University of Petroleum,Qingdao 266555,China. 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期136-136,共1页
Vertical structure of an unconformity can be divided into three layers:basal conglomerate or transgressive sand,weathered clay layer and leached rock.When the weathered clay layer has a little thickness or limited dis... Vertical structure of an unconformity can be divided into three layers:basal conglomerate or transgressive sand,weathered clay layer and leached rock.When the weathered clay layer has a little thickness or limited distribution,the overlying and underlying strata will contact directly,and the lithology is often different.This lithologic difference causes different fluid transporting capacity,and it also 展开更多
关键词 UNCONFORMITY STRUCTURE subtle pools ACCUMULATION SIMULATION
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Extensional Tectonics, Rifting, Formation of Sedimentary Basins, Cretaceous Volcanism, Emplacement of Dyke Swarms and Development of Hydrocarbon Pools: Case Studies from Peninsular India and Indian Ocean Region
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作者 K.S.MISRA 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第S1期61-62,共2页
Prolonged extensional regime in peninsular India resulted in formation of rift and grabens,elongated basins and Gondwana sedimentation along them.Downward progression of rift related faults caused decompression
关键词 Extensional Tectonics Formation of Sedimentary Basins RIFTING Cretaceous Volcanism Emplacement of Dyke Swarms and Development of Hydrocarbon pools
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Interdecadal Variability in Large and Small Warm Pools in Western Pacific and Their Association with Rainfall Anomalies
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作者 ZHOU Lian-Tong 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第1期56-61,共6页
This study investigated interdecadal variability of June–October(JJASO) the large and small warm pools in western Pacific and their association with rainfall anomalies using station and reanalysis data from 1958 to 2... This study investigated interdecadal variability of June–October(JJASO) the large and small warm pools in western Pacific and their association with rainfall anomalies using station and reanalysis data from 1958 to 2008.The results indicated that the large and small warm pools in western Pacific showed an interdecadal shift around 1986.The large warm pool years over western Pacific were found after 1986,whereas the small warm pool years were often seen throughout the periods before 1986.The analysis results also showed that there were obvious interdecadal variability in JJASO rainfall in Southeast China and warm pool in western Pacific.During 1958–1985(small warm pool years),the decrease in rainfall was associated with tropospheric moisture divergence and sinking motion over Southeast China and warm pool in western Pacific.However,during 1986–2008(large warm pool years),the increase in rainfall was associated with tropospheric moisture convergence and ascending motion.Further analysis showed that large warm pool contributed to the increase in surface latent heat fluxes over warm pool in the western Pacific.Thus,there was an increase in the amount of water vapor over Southeast China and warm pool in western Pacific,which contributed to increased rainfall in these regions. 展开更多
关键词 large and small warm pools interdecadal variability surface latent heat flux
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Sequencing and Analysis of G HR Gene from Genomic DNA Pools of Mink
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作者 Rong Min Xu Jiaping +2 位作者 Tu Jianfeng Gao Feng Xing Xiumei 《Animal Husbandry and Feed Science》 CAS 2018年第3期166-167,205,共3页
In order to study the single nucleotide polymorphisms (SNPs) of growth hormone receptor (GHR) gene in mink populations, genomic DNA pools of Minghua black minks and silver-blue minks were constructed, and the 10^t... In order to study the single nucleotide polymorphisms (SNPs) of growth hormone receptor (GHR) gene in mink populations, genomic DNA pools of Minghua black minks and silver-blue minks were constructed, and the 10^th exon of GHR gene was PCR amplified from the two DNA pools and sequenced. The results showed that two SNPs were found at position 209 (T/C) and position 533 (C/A) of the 10^th exon of GHR gene in the two mink populations. 展开更多
关键词 MINK Growth hormone receptor (GHR) gene DNA pools SEQUENCING Single nucleotide polymorphisms (SNPs)
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THE RELATIONS BETWEEN DEEP DYNAMIC PROCESS AND THE FORMATION OF OIL-GAS POOLS IN THE SONGLIAO BASIN,CHINA
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作者 Li Zhi’an(Changsha Institute of Geotectonics, Academia Sinica, Changsha, 410013, Hunan, China) 《Geotectonica et Metallogenia》 1996年第Z1期70-76,共7页
THE RELATIONS BETWEEN DEEPDYNAMIC PROCESS AND THEFORMATION OF OIL-GAS POOLS INTHE SONGLIAO BASIN, CHINALi Zhi’an(Changsha Institute of Geotectonics, Academia Sinica, Changsha, 410013, Hunan, China)Songliao basin, cru... THE RELATIONS BETWEEN DEEPDYNAMIC PROCESS AND THEFORMATION OF OIL-GAS POOLS INTHE SONGLIAO BASIN, CHINALi Zhi’an(Changsha Institute of Geotectonics, Academia Sinica, Changsha, 410013, Hunan, China)Songliao basin, crust structure, deep dynamics, the formation of oil-gas poolsThis essay deals in detail with the inhomogeneity of the crust structure and the variation of the Moho, the process of deep dynamics and also relations of deep dynamic process to the formation of oil-gas pools in Songliao Basin. 展开更多
关键词 Songliao BASIN CRUST structure DEEP dynamics the formation of oil-gas pools
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Local Impacts and Surface Characteristics of Cold Pools Wind Gust Observed from Thunderstorm
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作者 Richard Ayodeji Balogun Vincent Olanrewaju Ajayi Ifeoluwa Adebowale Balogun 《Atmospheric and Climate Sciences》 CAS 2022年第4期679-697,共19页
Cold pools and associated wind storms are frequent occurrences in Southwestern Nigeria, especially during the early monsoon phase. The associated surface wind gust frequently destroys properties resulting in economic ... Cold pools and associated wind storms are frequent occurrences in Southwestern Nigeria, especially during the early monsoon phase. The associated surface wind gust frequently destroys properties resulting in economic losses. Two case events were investigated in this study;one event occurred in May 2019 and the other occurred in March 2020, both in southwestern Nigeria. The National Oceanic and Atmospheric Administration (NOAA) National Center for Environmental Prediction (NCEP)/Climate Prediction Center (CPC) Infrared brightness temperatures and CPC Morphing technique (CMORPH) rainfall products were analysed alongside in-situ observations from the Nigerian Meteorological Agency (NiMET). Other data sources analysed are the National Aeronautics and Space Administration (NASA) Prediction Of Worldwide Energy Resources (POWER) and the World Wide Lightning Location Network (WWLLN). Cold pools were identified in the impacted communities as indicated by surface characteristics investigated from the in-situ observations. There was a sudden change in wind direction, with a simultaneous drop in temperature accompanied by increasing wind speed. Pressure and humidity were observed to change in the same period. Thunderstorms were also present in the impacted communities, as observed by the in-situ observations, in both case events. The presence of lightning as observed by WWLLN agrees with the in-situ thunderstorms. The cloud characteristics showed the presence of cloud shields, by their brightness temperature, over the impacted communities during the period of the cold pools in both case events. The systems were raining at the time of the observations in both cases, consistent with the in-situ thunderstorm observations. The communities were heavily impacted with several properties destroyed in the events. These early monsoon seasonal windstorms require a forecasting tool for their prediction and this study presents an eye-opener for further investigation and innovative research to address the menace. 展开更多
关键词 IMPACTS Cold pools WINDSTORMS THUNDERSTORMS RAINFALL DISASTERS
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Conditions for the Formation of Oil and Gas Pools in Tertiary Volcanics in the Western Part of the Huimin Sag, Shandong and Their Distribution
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作者 Liu Zerong and Xin Quanlin East China Petroleum Institute, Dongying, Shandong Wang Yongjie, Xu Piqin and Zhang Xiaofeng Shengli Oilfield, Dongying, Shandong Yang Shuren 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1989年第1期23-37,共15页
Conditions for the Formation of oil and gas pools in Tertiary volcanics in the western part of the Huimin sag, Shandong and then (?)stribution have been studied based on the geological, seismic and well-logging inform... Conditions for the Formation of oil and gas pools in Tertiary volcanics in the western part of the Huimin sag, Shandong and then (?)stribution have been studied based on the geological, seismic and well-logging information. In this paper, the types and lithofacies of the volcanic rocks in the western part of the Huimin sag are described; the relationship between rocks and electrical properties, the seismic reflection structures, the development and distribution of the volcanic rocks are expounded; and the fourfold role of the volcanic activities in the formation of the oil and gas pools is also dealt with. It is considered by the authors that the volcanic activities were not destructive to the formation of oil and gas pools but a factor favourable to the accumulation of organic matters and their conversion to hydrocarbon. The volcanic rocks might have served as reservoir rocks and cap rocks, or as a synsedimentary anticline. The prerequisites and important factors for the formation of oil and gas pools and their distribution are pointed out in the paper. 展开更多
关键词 Conditions for the Formation of Oil and Gas pools in Tertiary Volcanics in the Western Part of the Huimin Sag
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Numerical Analysis of the Magnetization Behavior in Magnetic Resonance Imaging in the Presence of Multiple Chemical Exchange Pools
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作者 Kenya Murase 《Open Journal of Applied Sciences》 2017年第1期1-14,共14页
The purpose of this study was to demonstrate a simple and fast method for solving the time-dependent Bloch-McConnell equations describing the behavior of magnetization in magnetic resonance imaging (MRI) in the presen... The purpose of this study was to demonstrate a simple and fast method for solving the time-dependent Bloch-McConnell equations describing the behavior of magnetization in magnetic resonance imaging (MRI) in the presence of multiple chemical exchange pools. First, the time-dependent Bloch- McConnell equations were reduced to a homogeneous linear differential equation, and then a simple equation was derived to solve it using a matrix operation and Kronecker tensor product. From these solutions, the longitudinal relaxation rate (R1ρ) and transverse relaxation rate in the rotating frame (R2ρ) and Z-spectra were obtained. As illustrative examples, the numerical solutions for linear and star-type three-pool chemical exchange models and linear, star- type, and kite-type four-pool chemical exchange models were presented. The effects of saturation time (ST) and radiofrequency irradiation power (ω1) on the chemical exchange saturation transfer (CEST) effect in these models were also investigated. Although R1ρ and R2ρ were not affected by the ST, the CEST effect observed in the Z-spectra increased and saturated with increasing ST. When ω1 was varied, the CEST effect increased with increasing ω1 in R1ρ, R2ρ, and Z-spectra. When ω1 was large, however, the spillover effect due to the direct saturation of bulk water protons also increased, suggesting that these parameters must be determined in consideration of both the CEST and spillover effects. Our method will be useful for analyzing the complex CEST contrast mechanism and for investigating the optimal conditions for CEST MRI in the presence of multiple chemical exchange pools. 展开更多
关键词 Bloch-McConnell Equations MULTIPLE CHEMICAL EXCHANGE pools CHEMICAL EXCHANGE Saturation TRANSFER (CEST) Magnetic Resonance Imaging (MRI) Amide Proton TRANSFER (APT) MRI Numerical Analysis
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Bacteriological Quality of Swimming Pools Water in Port Harcourt Metropolis
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作者 Smart Enoch Amala Constancy Prisca Aleru 《Natural Science》 2016年第3期79-84,共6页
The bacteriological quality of swimming pool water in Port Harcourt Metropolis was investigated. Ten (10) swimming pools were examined for microbial quality. Out of the 10 swimming pools, 4 (2, 4, 7 and 9) had bacteri... The bacteriological quality of swimming pool water in Port Harcourt Metropolis was investigated. Ten (10) swimming pools were examined for microbial quality. Out of the 10 swimming pools, 4 (2, 4, 7 and 9) had bacterial isolates of 40 (100%). Swimming pools 2, 4, 7 and 9 had the bacterial isolates of 10 (25%), 8 (20%), 10 (25%) and 12 (30%), respectively. Of the forty (40) bacterial isolates identified, which represented 100 percent, 22 (55%) were identified as Staphylococcus epidermidis, 10 (25%) Bacillus cereus, 6 (16%) Micrococcus and 2 (5%) Staphylococcus aureus. Among the four swimming pools, 2 and 9 did not have the isolates of Staphylococcus aureus and Micrococcus, respectively. Based on the World Health Organisation (WHO) standard for recreational waters, the absence of coliform and fecal coliform bacteria (E. coli) revealed that the ten (10) swimming pools used for this study are considered to be within the acceptable limits for certifying microbiological water quality. However, there is a need for care and continuous maintenance of the swimming pools. 展开更多
关键词 Bacteriological QUALITY Swimming pools WATER
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GEOTHERMAL EVOLUTION OF THE DIWA-TYPE SEDIMENTARY BASIN AND ITS CONTROLLING ON THE FORMATION OF OIL/GAS POOLS
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《Geotectonica et Metallogenia》 1994年第Z2期113-115,共3页
关键词 GAS GEOTHERMAL EVOLUTION OF THE DIWA-TYPE SEDIMENTARY BASIN AND ITS CONTROLLING ON THE FORMATION OF OIL/GAS pools ITS
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