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Spatiotemporal variations of ecosystem services and driving factors in the Tianchi Bogda Peak Natural Reserve of Xinjiang,China
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作者 ZHU Haiqiang WANG Jinlong +2 位作者 TANG Junhu DING Zhaolong GONG Lu 《Journal of Arid Land》 SCIE CSCD 2024年第6期816-833,共18页
Nature reserves play a significant role in providing ecosystem services and are key sites for biodiversity conservation.The Tianchi Bogda Peak Natural Reserve(TBPNR),located in Xinjiang Uygur Autonomous Region,China,i... Nature reserves play a significant role in providing ecosystem services and are key sites for biodiversity conservation.The Tianchi Bogda Peak Natural Reserve(TBPNR),located in Xinjiang Uygur Autonomous Region,China,is an important ecological barrier area in the temperate arid zone.The evaluation of its important ecosystem services is of great significance to improve the management level and ecological protection efficiency of the reserve.In the present study,we assessed the spatiotemporal variations of four ecosystem services(including net primary productivity(NPP),water yield,soil conservation,and habitat quality)in the TBPNR from 2000 to 2020 based on the environmental and social data using the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.In addition,the coldspot and hotspot areas of ecosystem services were identified by hotspot analysis,and the trade-off and synergistic relationships between ecosystem services were analyzed using factor analysis in a geographic detector.During the study period,NPP and soil conservation values in the reserve increased by 48.20%and 25.56%,respectively;conversely,water yield decreased by 16.56%,and there was no significant change in habitat quality.Spatially,both NPP and habitat quality values were higher in the northern part and lower in the southern part,whereas water yield showed an opposite trend.Correlation analysis revealed that NPP showed a synergistic relationship with habitat quality and soil conservation,and exhibited a trade-off relationship with water yield.Water yield and habitat quality also had a trade-off relationship.NPP and habitat quality were affected by annual average temperature and Normalized Difference Vegetation Index(NDVI),respectively,while water yield and soil conservation were more affected by digital elevation model(DEM).Therefore,attention should be paid to the spatial distribution and dynamics of trade-off and synergistic relationships between ecosystem services in future ecological management.The findings of the present study provide a reference that could facilitate the sustainable utilization of ecosystem services in the typical fragile areas of Northwest China. 展开更多
关键词 net primary productivity(NPP) water yield soil conservation habitat quality Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model geographic detector Tianchi Bogda Peak Natural reserve
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Coupling Relationship Analysis on Households′ Production Behaviors and Their Influencing Factors in Nature Reserves:A Structural Equation Model 被引量:6
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作者 WANG Changhai WEN Yali +1 位作者 DUAN Wei HAN Feng 《Chinese Geographical Science》 SCIE CSCD 2013年第4期506-518,共13页
A households′production behavior directly influences the quality of the environment and determines the successful development of nature reserves.Meanwhile,the households′production behaviors are complicated by inter... A households′production behavior directly influences the quality of the environment and determines the successful development of nature reserves.Meanwhile,the households′production behaviors are complicated by interrelated factors,such as protection attitudes,resource endowment,and family wealth.This research evaluated households near the Crested Ibis National Nature Reserve in Shaanxi Province,acquiring data from 436 households around Yang County and Ningshan County in the south slope of Qinling Mountains,China.Based on the collected data,we developed a structural equation model to evaluate the coupling relationships among households′ protection attitudes,production behaviors,resource endowment,and family wealth.The results showed that:1) households with great resource endowment had more negative attitudes,probably due to their greater protection costs;2) the households with higher education levels had worse protection attitudes;3) the households with more family wealth were likely to use fewer fertilizers,pesticides,and firewood;4) the households with more resource endowment showed less production and management behaviors;5) the enhancement of households' attitudes improved production behaviors to protection the environment,but the effects were not statistically significant.Our results provide a basis for the government's protection policy making,exploring the effective management measures that are beneficial for both nature reserve management and community development. 展开更多
关键词 国家级自然保护区 结构方程模型 经营行为 耦合关系 家庭 生产 影响因素 自然保护区管理
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The Value Constrained Production Decline Model and Its Application in Reserve Valuation
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作者 Zhu Jiucheng Wang Zhen Zhang Rui 《Petroleum Science》 SCIE CAS CSCD 2005年第3期69-72,共4页
In the asset valuation of oil and gas reserves, it is discovered that the production decline trend of wells is not very obvious and that it is hard to make a production forecast matching the production history, thus r... In the asset valuation of oil and gas reserves, it is discovered that the production decline trend of wells is not very obvious and that it is hard to make a production forecast matching the production history, thus resulting in a significant deviation of oil and gas asset value. For production with a significant fluctuation, the value deviation is also considerable if the matching production, which is predicted with classical decline methods, cannot appropriately reflect the time value distribution of actual production. To mitigate such a deviation, a concept is proposed concerning the value constrained production forecast and the value constrained production decline model is developed. A field case is demonstrated as an application of such a model. The model can significantly decrease the risk in the value deviation of a production decline analysis and be applied to the production forecasts for a single well, well clusters, blocks or field scale, and even for other mining industries. 展开更多
关键词 Oil and gas field reserve valuation production forecast reservoir engineering petroleum economics
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The analysisof frequent adjustments of legal deposit reserve ratio of People's Bank of Ghina
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作者 邓敏 《大观周刊》 2012年第49期100-100,共1页
关键词 金融机构 金融体制 银行业务 PBOC
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Production evolution patterns and development stage division of waterflooding oilfields
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作者 JI Bingyu XU Ting +2 位作者 GAO Xingjun YU Hongmin LIU He 《Petroleum Exploration and Development》 SCIE 2023年第2期433-441,共9页
The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle m... The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle model. With the new model, the statistical correspondence between the production decline stage and the reserve-production imbalance is clarified,and the correlation of water cut with the recovery percent of recoverable reserves is discussed, providing quantitative basis of reservoir engineering for dividing development stages of oilfield and defining mature oilfields. According to the statistics of oilfields in eastern China, the time point corresponding to the reserve-production balance coefficient dropping to less than 1dramatically is well correlated the beginning point of production decline, thus the time when the reserve-production balance coefficient drops dramatically can be taken as the initiation point of production decline stage. The research results show that the water cut and the recovery percent of recoverable reserves have a good statistical match in the high water cut stage, and it is more rational to take both the start point of production decline stage and the water cut of 90%(or the recovery percent of recoverable reserves of 80%) as the critical criteria for defining a mature oilfield. Five production evolution patterns can be summarized as follows: growth–peak plateau–stepped decline, growth–stepped stabilizing–stepped decline, growth–stepped stabilizing–rapid decline, growth–peak plateau–rapid decline, and growth–continuous decline. 展开更多
关键词 waterflooding oilfield production evolution development stage division recoverable reserves mature oilfield
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Fractional flow reserve and non-hyperemic indices:Essential tools for percutaneous coronary interventions
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作者 Amine Mamoun Boutaleb Chadi Ghafari +1 位作者 Claudiu Ungureanu Stéphane Carlier 《World Journal of Clinical Cases》 SCIE 2023年第10期2123-2139,共17页
Hemodynamical evaluation of a coronary artery lesion is an important diagnostic step to assess its functional impact.Fractional flow reserve(FFR)received a class IA recommendation from the European Society of Cardiolo... Hemodynamical evaluation of a coronary artery lesion is an important diagnostic step to assess its functional impact.Fractional flow reserve(FFR)received a class IA recommendation from the European Society of Cardiology for the assessment of angiographically moderate stenosis.FFR evaluation of coronary artery disease offers improvement of the therapeutic strategy,deferring unnecessary procedures for lesions with a FFR>0.8,improving patients'management and clinical outcome.Post intervention,an optimal FFR>0.9 post stenting should be reached and>0.8 post drug eluting balloons.Non-hyperemic pressure ratio measurements have been validated in previous studies with a common threshold of 0.89.They might overestimate the hemodynamic significance of some lesions but remain useful whenever hyperemic agents are contraindicated.FFR remains the gold standard reference for invasive assessment of ischemia.We illustrate this review with two cases introducing the possibility to estimate also non-invasively FFR from reconstructed 3-D angiograms by quantitative flow ratio.We conclude introducing a hybrid approach to intermediate lesions(DFR 0.85-0.95)potentially maximizing clinical decision from all measurements. 展开更多
关键词 Fractional flow measurements Coronary artery physiology Quantitative flow reserve Non-hyperemic pressure ratios
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Non-invasive Angiographic-based Fractional Flow Reserve:Technical Development,Clinical Implications,and Future Perspectives
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作者 Joyce Peper Michiel L.Bots +1 位作者 Tim Leiner Martin J.Swaans 《Current Medical Science》 SCIE CAS 2023年第3期423-433,共11页
New non-and less-invasive techniques have been developed to overcome the procedural and operator related burden of the fractional flow reserve(FFR)for the assessment of potentially significant stenosis in the coronary... New non-and less-invasive techniques have been developed to overcome the procedural and operator related burden of the fractional flow reserve(FFR)for the assessment of potentially significant stenosis in the coronary arteries.Virtual FFR-techniques can obviate the need for the additional flow or pressure wires as used for FFR measurements.This review provides an overview of the developments and validation of the virtual FFR-algorithms,states the challenges,discusses the upcoming clinical trials,and postulates the future role of virtual FFR in the clinical practice. 展开更多
关键词 coronary artery disease quantitative flow ratio fractional flow reserve diagnostic accuracy physiology guided percutaneous coronary intervention
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Productivity analysis in nature reserve:A case study in Hunan Province 被引量:1
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作者 Wang Lan-hui Tian Shu-rong 《Forestry Studies in China》 CAS 2007年第1期80-84,共5页
Although there are abundant natural resources in nature reserves, poverty is a common feature of the social economy in the communities surrounding nature reserves. Income from forestry is still the main source for res... Although there are abundant natural resources in nature reserves, poverty is a common feature of the social economy in the communities surrounding nature reserves. Income from forestry is still the main source for residents living around nature reserves. The structure of inputs and outputs, i.e. productivity, in the forestry sector in nature reserves is quite different from one reserve to another. Productivity can be measured by Data Envelopment Analysis (DEA) methods owing to the characteristics of DEA. The promotion of productivity in nature reserve is an effective way to improve the living condition in areas neighboring nature reserves. Thus, one typical national nature reserve in Hunan is selected in this study with the intent to measure productivity in the area and then to analyze the factors affecting its productivity. 展开更多
关键词 nature reserve productIVITY EFFICIENCY
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Carbon isotope ratios of n-alkanoic acids: new organic proxies for paleo-productivity in Antarctic ponds
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作者 CHEN Xin JIN Jing +5 位作者 NIE Yaguang ZHANG Jifeng DONG Liang HUANG Xianyu Steven D()EMSLIE LIU Xiaodong 《Advances in Polar Science》 CSCD 2023年第4期304-317,共14页
Primary productivity in the Antarctic aquatic environment with simple ecosystems is sensitive to climate and environmental fluctuations.We investigatedδ13C values for n-alkanoic acids derived from phototrophic organi... Primary productivity in the Antarctic aquatic environment with simple ecosystems is sensitive to climate and environmental fluctuations.We investigatedδ13C values for n-alkanoic acids derived from phototrophic organisms in a lacustrine sediment core(IIL3)to indicate primary productivity in ponds on Inexpressible Island in the western Ross Sea,Antarctica.Short-chain n-alkanoic acids(C14–C18)were abundant in the IIL3 sediment profile.The carbon isotope ratios of short-chain n-alkanoic acids in the sediment samples and floating microbial mats were similar,indicating that the short-chain n-alkanoic acids in the IIL3 sediment profile predominantly originated from phototrophic organisms.Theδ13C values for the short-chain n-alkanoic acids varied widely through the sediment profile,and 13C-enrichment of n-alkanoic acids was most likely related to high productivity due to carbon-limited conditions caused by enhanced photosynthetic efficiency.Theδ13C values for the n-alkanoic acids changed over the past 3200 years in similar ways to organic proxies for aquatic productivity(n-alkanoic acid and sterol sedimentary fluxes).C16 n-alkanoic acid was enriched in 13C in periods of high aquatic productivity~750–1650 and 3000–3200 a BP but depleted in 13C in periods of relatively low productivity~150–600 and 2500–3000 a BP.The results indicated that carbon isotope ratios of lipids from phototrophic organisms could be used as new proxies to reconstruct paleo-productivity in Antarctic lakes and ponds and therefore improve our understanding of past climate changes. 展开更多
关键词 East Antarctica lipid biomarkers carbon isotopic ratios pond primary productivity climate change
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Effects of Different Row Ratios of Male and Female Parents and Application Amount of Nitrogen Fertilizer on Hybrid Wheat Seed Production and Its Component Factors 被引量:1
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作者 Can SUN Renwu RUAN +7 位作者 Lili YAN Dan HU Xingbei LIU Hengzhi SHE Manman XU Zhongan LI Zelin YI Yuheng YANG 《Asian Agricultural Research》 2017年第3期69-73,共5页
In order to screen suitable high hybrid wheat seed production technology,the split-plot experiment design was adopted and study was carried out about the effects of the different row ratios of male and female parents ... In order to screen suitable high hybrid wheat seed production technology,the split-plot experiment design was adopted and study was carried out about the effects of the different row ratios of male and female parents and application amount of nitrogen fertilizer on hybrid wheat seed production and its component factors. The results showed that the seed production increased with the increase in the number of female parent row. When the row ratio of male and female parents was 2 ∶ 6,the seed production was 3 683. 8 kg/ha; when the application amount of nitrogen fertilization was 50 kg/ha,the seed production was 3 649. 4 kg/ha; the interaction between the row ratio of male and female parents and the application amount of nitrogen fertilizer indicated that when the row ratio of male and female parents was 2∶ 6 and the application amount of nitrogen fertilizer was 300 kg/ha,the seed production reached the highest( 4160. 6 kg/ha). The row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the component factors of seed production,including the number of grains per spike,spike weight and setting percentage. When the row ratio of male and female parents was 2∶ 5,the number of grains per spike,spike weight and setting percentage were the highest at 26. 7 grains,1. 12 g,and 62. 6% respectively; when application amount of nitrogen fertilizer was 450 kg/ha,the number of grains per spike,spike weight and setting percentage were the highest at 26. 0 grains,1. 08 g,and59. 2% respectively; the interaction of row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the number of grains per spike,spike weight and setting percentage; when the row ratio of male and female parents was 2∶ 5 and the application amount of nitrogen fertilizer was 300 kg/ha,the number of grains per spike,spike weight and setting percentage were the highest at 29. 6grains,1. 24 g,and 71. 6% respectively. The number of grains per spike is the largest component factor for seed production. Increasing the number of grains per spike can increase the seed production. According to the effects of row ratio of male and female parents and application amount of nitrogen fertilizer on the component factors of seed production,the optimal condition was 2∶ 5-2∶ 6 for row ratio of male and female parents and 300-450 kg/ha for application amount of nitrogen fertilizer. 展开更多
关键词 Hybrid wheat Row ratio of male and female parents Nitrogen fertilizer Seed production
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Automatic Detection Instrument for the Ratio of Chlorine to Bromine in Oxidized Liquid of Bromine Production Based on Fuzzy Method
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作者 Yu Naigong Wang Kaiyan 《仪器仪表学报》 EI CAS CSCD 北大核心 2006年第z1期159-161,共3页
In the process of bromine production,because of lag adjustment methods,there are problems of adjusting delay,raw material wastage and low growth rate.By considering the nature of bromine production,with the help of fu... In the process of bromine production,because of lag adjustment methods,there are problems of adjusting delay,raw material wastage and low growth rate.By considering the nature of bromine production,with the help of fuzzy data processing method,computer detection and display technique,we designed an automatic detection instrument for the ratio of chlorine to bromine in oxidized liquid of bromine production.This instrument can be used to detect the different parameters of raw materials adjustment and control in real time,and afford assurance that raw materials will be adjusted in time.This paper briefly introduces the working mechanism,hardware and software design of the instrument. 展开更多
关键词 BROMINE production fuzzy relation list ratio of CHLORINE to BROMINE in OXIDIZED LIQUID OXIDIZING electric potential automatic detection
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Effect of Pelleted Total Mixed Ration with Different Concentrate-roughage Ratios on Production Performance and Serum Biochemical Parameters of Fattening Hainan Black Goats
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作者 Liu Quanwei Wang Feng +5 位作者 Wei Limin Tan Shuyi Sun Ruiping Huang Lili Xing Manping Zheng Xinli 《Animal Husbandry and Feed Science》 CAS 2019年第1期4-8,共5页
[Objective] This paper was to study effects of pelleted total mixed ration with different concentrate-roughage ratios on production performance and serum biochemical parameters of fattening Hainan black goats.[Method]... [Objective] This paper was to study effects of pelleted total mixed ration with different concentrate-roughage ratios on production performance and serum biochemical parameters of fattening Hainan black goats.[Method] Thirty-six fattening Hainan black goats with the same genetic background and similar initial weight of(14.08±0.13) kg were randomly assigned into three treatments. Goats were fed with Juncao + concentrate(control group), pelleted total mixed ration I(concentrate: roughage 50 ∶50, group Ⅰ) and Ⅱ(concentrate: roughage 45∶55, group Ⅱ), respectively. The test lasted 45 d.[Result] The final weight, daily gain and feed intake of rams in experimental group Ⅰ were significantly higher than those of control group and experimental group Ⅱ(P<0.05);the final weight and daily gain of rams in experimental group Ⅰ were also markedly higher than those of experimental group Ⅱ(P<0.05);the feed/gain of rams in experimental group Ⅰ was significantly lower than those in control group and experimental group Ⅱ(P<0.05). The feed gain cost of rams in experimental group Ⅰ was markedly lower than that in experimental group Ⅱ( P<0.05), but was significantly higher than that in experimental group Ⅰ(P<0.05);the gross profit of rams in experimental group Ⅰ was significantly higher than those in control group and experimental group Ⅱ(P<0.05). Compared with control group and experimental group Ⅱ, the serum total protein and glucose lev-els in experimental group Ⅱ increased significantly(P<0.05), but the urea nitrogen content reduced(P>0.05).[Conclusion] When the concentrateroughage ratio of pelleted total mixed ration was 50∶50, the fattening effect of Hainan black goat was better, and the serum total protein and glucose levels were evidently improved. 展开更多
关键词 FATTENING HAINAN black GOAT Pelleted total mixed ration Concentrate-roughage ratio production performance SERUM BIOCHEMICAL parameters
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Fuzzy-Bayes Decision Making with Reserved Judgement
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作者 Houju Hori Jr. 《Journal of Applied Mathematics and Physics》 2023年第9期2783-2788,共6页
This paper discusses a method for identifying states in a multistage Decision Making Problem in which an Indifferent Event is either predetermined or can be automatically derived after the fact. First, when they are p... This paper discusses a method for identifying states in a multistage Decision Making Problem in which an Indifferent Event is either predetermined or can be automatically derived after the fact. First, when they are pre-set, the amount of possible information about Indifferent Event tends to be large. Therefore, since the decision is risk tolerant, the Max-Product method of Tanaka et al. is used to calculate the expected utility possibility. Next, in the case of automatic derivation after the fact, the amount of information on the possibility of Indifferent Event is relatively small, so the expected utility possibility is derived using Zadeh’s Fuzzy Event Possibility Measure. Here, it is assumed that the setting of the utility function is independent of the information on the occurrence of the Indifferent Event and is identified by the decision maker by lot drawing using the certainty equivalence method. As a concrete example, we focus on the pass/fail decision of a recommendation test, which is a two choice question in the No-Data Problem, and illustrate the multistage state identification method. . 展开更多
关键词 Fuzzy Event reserved Judgment Indifferent Event Expected Utility Max-product
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Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, A cartia tonsa:a laboratory study 被引量:1
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作者 SHAYEGAN Majid ESMAEILI FEREIDOUNI Abolghasem +1 位作者 AGH Naser JANI KHALILI Khosrow 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第4期709-718,共10页
The ef fects of salinity on the copepod, A cartia tonsa in terms of daily egg production rate(EPR), hatching success, fecal pellet production rate(FPR), naupliar development time and survival, sex ratio, and total lif... The ef fects of salinity on the copepod, A cartia tonsa in terms of daily egg production rate(EPR), hatching success, fecal pellet production rate(FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods(seven consecutive days). Results show EPR was aff ected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females(long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages(56.7% and 52.2%, respectively) were signifi cantly observed at two salinities of 13 and 20 compared to that at 35(25%). Total longevity of females was not af fected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa. 展开更多
关键词 实验室条件 桡足类 产蛋率 生产率 盐度 寿命 粪便 孵化成功率
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A New Method for the Dynamic Reserves of Gas Condensate Reservoir Using Cyclic Gas Injection Based on the Effects of Reinjection Ratio and Water Influx
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作者 Yu Xiong Ling Wang +1 位作者 Zhongqian Zhu Wei Xie 《Engineering(科研)》 2015年第7期455-461,共7页
As we all know, cyclic gas injection is one of the most effective development methods to improve condensate oil recovery. When dealing with the calculation of the reserves, the injection-production differences and wat... As we all know, cyclic gas injection is one of the most effective development methods to improve condensate oil recovery. When dealing with the calculation of the reserves, the injection-production differences and water influx create great influence on the accuracy. Based on the existing research, we proposed a new material balance equation which considered the differences of composition between produced and injected fluids and the effect of water influx, and a solution was provided in this paper. The results of the method are closer to the actual situation because they are built on the law of conservation of mass, and the using of curve fitting method can not only avoid the use of water influx coefficient but also obtain the water influx rate and reserves at the same time. The YH-23 gas condensate reservoir is taking as a typical subject to do the research, which has been exploited by cycle gas injection for 14 years. Three different methods are used to calculate the reserves, and the results show that the method proposed in this paper has minimum error of 2.96%. 展开更多
关键词 CONDENSATE GAS reservoir Cyclic GAS Injection Dynamic reserveS Material Balance Method REINJECTION ratio Water INFLUX
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Relationship Among Reserve Ratio, Government Spending and Economic Growth
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作者 ZHANGYan ZHOUSheng-Wu 《Journal of China University of Mining and Technology》 EI 2005年第2期157-162,共6页
The relationship among reserve ration, government spending and economic growth was analyzed. A monetary endogenous growth model is well developed by taking into account the growth-enhancing effects of re- serve-augmen... The relationship among reserve ration, government spending and economic growth was analyzed. A monetary endogenous growth model is well developed by taking into account the growth-enhancing effects of re- serve-augmenting seigniorage. If the government spends all the seigniorage revenue on the provision of a public input which has positive externality on the private sector’s production, some results to be utterly different from Bronx’s have been obtained: the economy has a unique saddle-balanced growth path, but it has nothing to do with reserve ratio. However, the higher reserve ratio, the faster speed of economic convergence. 展开更多
关键词 经济增长 政府支出 税收 储备率
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Biohydrogen Production from Synthetic Waste Co-digested with Liquid Dairy Cow Manure: Effect of Temperature and Mixing Ratio
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作者 S. A. Lateef T. Yamashiro N. Beneragama M. Iwasaki Y. Moriya C. Ying K. Umetsu 《Journal of Agricultural Science and Technology(A)》 2011年第8期1303-1306,共4页
关键词 生物制氢 固体废物 基板温度 奶牛粪 消化 混合率 挥发性固体 液态
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Risk-opportunity analyses and production peak forecasting on world conventional oil and gas perspectives 被引量:1
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作者 Zhang Jian Sun Zandong +2 位作者 Zhang Yiwei Sun Youshun Nail Toksoz 《Petroleum Science》 SCIE CAS CSCD 2010年第1期136-146,共11页
To investigate the situation of conventional oil and gas, this paper examines the global oil and gas discoveries, proved reserves, production, consumption and price. All the influencing factors can be subjected to ris... To investigate the situation of conventional oil and gas, this paper examines the global oil and gas discoveries, proved reserves, production, consumption and price. All the influencing factors can be subjected to risk and opportunity analyses, so in the paper, we build upon a risk-opportunity analysis framework, which is a new train of thought. To forecast the peak time of oil and gas production, we used the methods of multi-Hubbert model forecasting and data forecasting. Our results showed that the world oil production will reach a peak between 2010 and 2015 and the gas production will reach a peak around 2030 Oil peak is coming and gas peak is on the way. The main purpose of forecasting oil and gas production peak is give people enough time for preparing mitigation and adaptation plans. This means taking decisive action well before the problem is obvious. 展开更多
关键词 production reserve RISK OPPORTUNITY forecasting
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Multi-center pragmatic studies evaluating the time indicator of cardiac perfusion reserve 被引量:3
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作者 Lin Xiong Shouzhong Xiao +9 位作者 Qiang Zhou Xianrong Wu Zifu Xiao Xingming Guo Delin Lu Wanrong Zhao Xiaojun Wu Xiaobo Yan Yanxia Zhao Jianming Liu 《Journal of Biomedical Science and Engineering》 2013年第1期1-7,共7页
Background: Since the greater part of coronary blood flow takes place during the diastolic phase of each cardiac cycle, a time indicator of myocardial perfusion reserve, the ratio of diastolic to systolic duration (D/... Background: Since the greater part of coronary blood flow takes place during the diastolic phase of each cardiac cycle, a time indicator of myocardial perfusion reserve, the ratio of diastolic to systolic duration (D/S ratio), was presented. The objective of this study was to evaluate the accuracy and precision, the biological implication, and the applications of D/S ratio. Methods: Multi-center pragmatic studies evaluating the time indicator of cardiac perfusion reserve were performed. Related experiments, clinical trials, and surveys were conducted at 5 centers. Results: The results showed that the measurement of D/S ratio is both accurate and precise;the mean values of D/S of all of the 3 species studied (human, rabbit, and rat) were greater than 1. These application studies on D/S ratio showed that a close negative correlation existed between D/S ratio and New York Heart Association Functional Classification (NYHA FC) (r = –0.659, p pregnant women with pre-eclampsia and either normal pregnant women or non-pregnant women were significant (p Conclusions: D/S ratio has important biological implication, which is a safe, easy, reliable, and effective indicator, can be used to evaluate fitness levels, served as a pathophysiological marker for screening of cardiovascular disease (CVD), for predicting risk of cardiac events, and for evaluating the severity and prognosis of CVD. 展开更多
关键词 ratio of DIASTOLIC to SYSTOLIC Duration (D/S) Accuracy Precision CARDIAC reserve CARDIAC Safety Fitness
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A Novel Peak-to-Average Power Ratio Reduction Scheme via Tone Reservation in OFDM Systems 被引量:1
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作者 Jurong Bai Yong Li +2 位作者 Wei Cheng Huimin Du Yanben Wang 《China Communications》 SCIE CSCD 2017年第11期279-290,共12页
In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multipl... In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multiplexing systems. During the SCR procedure, only the element with the maximal amplitude is picked for processing, which not only decreases the algorithm complexity, but also helps to overcome the BER deterioration. With the LSA method, the amplitude of the peak-cancelling signals can approximate to that of the original clipping noise as much as possible. Through the combination of the optimization factor in the LSA method, the classic SCR method can achieve better PAPR reduction with faster convergence. Simulation results show that the proposed SCR-LSA TR scheme has less in-band distortion and smaller out-of-band spectral radiation. The BER of the proposed scheme shows a better performance especially under the 16-QAM over the additive white Gaussian noise channel. 展开更多
关键词 orthogonal frequency division multiplexing peak-to-average power ratio tone reservation signal to clipping noise ratio
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