How nutritional conditions during early development affect an organism’s phenotype at adulthood is still poorly understood despite a plethora of research on developmental plasticity.The"environmental matching&qu...How nutritional conditions during early development affect an organism’s phenotype at adulthood is still poorly understood despite a plethora of research on developmental plasticity.The"environmental matching"hypothesis predicts that individuals will have high fitness providing that their adult environment"matches"what they experienced during development.In contrast,the"silver spoon"hypothesis predicts that individuals who obtain better developmental resources will be generally superior.Here we tested these two hypotheses and examined the underlying hormonal mechanisms by manipulating the early dietary protein content of African clawed frogs(Xenopus laevis)for a year with a 2×2 factorial experimental design.We found that only a lowprotein food during development enhanced the vocal competition ability of male X.laevis,and that vocal dominance was associated with higher cortisol levels but not related with testosterone content.These results were not congruent with the"environmental matching"hypothesis or with the"silver spoon"hypothesis,suggesting the behavioral plasticity during development is more complex than our expectation in amphibians.展开更多
Given its relevance to the exploitation of ultra-low permeability reservoirs,which account for a substantial proportion of the world’s exploited and still unexploited reserves,in the present study the development of ...Given its relevance to the exploitation of ultra-low permeability reservoirs,which account for a substantial proportion of the world’s exploited and still unexploited reserves,in the present study the development of an adequate water injection system is considered.Due to the poor properties and weak seepage capacity of these reservoirs,the water injection pressure typically increases continuously during water flooding.In this research,the impact on such a process of factors as permeability,row spacing,and pressure gradient is evaluated experimentally using a high-pressure large-scale outcrop model.On this basis,a comprehensive evaluation coefficient is introduced able to account for the effective driving pressure.展开更多
The dynamics of blood lead (Pb-B) and blood zinc protoporphyrin (ZPP-B) of women in early pregnancy and parturient women with lead exposure and the effects on fetus development were investigated. Pb-B of lead-exposed ...The dynamics of blood lead (Pb-B) and blood zinc protoporphyrin (ZPP-B) of women in early pregnancy and parturient women with lead exposure and the effects on fetus development were investigated. Pb-B of lead-exposed women was high: 0.984 μmol/L (20.38 μg/dl) and ZPP was 84.52μg/dl. Cord blood Pb-B was 0.896 μmol/L(18.56μg/dl)and cord blood ZPP was 69.24μg/dl. In the control group, Pb-B was 0.261μmol/L(5.41μg/dl), ZPP-B, 37.59 μg/dl, cord blood, Pb-B 0.34 μmol/L (7.93 μg/dl), and cord ZPP-B 49.0μg/dl. There was a significant correlation between blood lead and blood ZPP, maternal Pb-B and cord Pb-B, maternal Pb-B and cord ZPP-B. The significance of the consistency of high level Pb-B and the effects on fetus development is discussed.展开更多
X oilfield is located in Bohai Sea area, in which G oil formation is a typical drape anticline structure, which is composed of multiple sets of thick sandy conglomerate and multiple sets of argillaceous intercalation....X oilfield is located in Bohai Sea area, in which G oil formation is a typical drape anticline structure, which is composed of multiple sets of thick sandy conglomerate and multiple sets of argillaceous intercalation. From the perspective of development effect, muddy interlayer has a great impact on the oilfield. In this paper, through core identification and well logging identification, the electrical discrimination standard is summarized to identify the interlayer. Through statistics and analysis of the production performance of actual wells, the influence of muddy interlayer on the development performance of oil wells is summarized. This study provides guidance for the development of strong bottom water reservoirs with interlayer.展开更多
Oil field waterflooding is a complex man-controlled systematic behavior, and the related evaluation methods vary greatly. This paper put forward a fuzzy comprehensive method of evaluating controlled development level ...Oil field waterflooding is a complex man-controlled systematic behavior, and the related evaluation methods vary greatly. This paper put forward a fuzzy comprehensive method of evaluating controlled development level by analysis of the macroscopic evaluation to oil field waterflooding effect with combination of original reservoir geological state. This fuzzy evaluation technique bears unique advantages because there is little difference among evaluation indexes which represent the dynamic and static state of regional neighborhood of development units (blocks, Production Company<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> etc.). Not only the mathematical method for evaluating oil field waterflooding effect is set up, but also the method is applied in three blocks of D oil field. The calculated results show the effectiveness and practicability of the method.</span></span></span>展开更多
Shale gas is a practical resource with great potential that could be economically explored and developed in the near future. It has been commercially developed in North America and other places. Featuring a vast distr...Shale gas is a practical resource with great potential that could be economically explored and developed in the near future. It has been commercially developed in North America and other places. Featuring a vast distribution, a low abundance,unfavorable reservoir conditions, ultra-low permeability and a fast production decline, shale gas is more difficult to develop than conventional natural gas, as it needs advanced drilling and completion technology to develop. During the early stage of shale gas exploration and development, the United States offered enterprises necessary incentives such as tax reductions and exemptions and subsidies to achieve sustainable shale gas development and encourage technological progresses. By comparing the state of China's shale gas development with that of the US' in terms of geological conditions, production technology,market price, tax relief, subsidy periods and amount, this paper intends to put forward related suggestions for the effective development of shale gas according to the current status of development.展开更多
Based on the newest understandings of geological assessment and new progresses in engineering technologies in the development of shale gas rich in the southern Sichuan Basin,this paper analyzed the shale gas enrichmen...Based on the newest understandings of geological assessment and new progresses in engineering technologies in the development of shale gas rich in the southern Sichuan Basin,this paper analyzed the shale gas enrichment laws and the key factors of its commercial production,discussed the scale and efficient development modes,and clarified the further developing orientation.The following findings were concluded.(1)The Lower Silurian Longmaxi shale is the sweetest spot in this study area with a low density and a high uranium/thorium(U/Th)ratio,TOC content,quartz content,and free gas content.Besides,its distribution laws are mainly controlled by the sedimentary facies of deep water shelf.(2)The overpressured zones away from the ancient(present)erosion zones and large faults,mainly controlled by multi-stage tectonic evolution,belong to the most favorable sweet spots not only because there are well-developed organic matters and pores but the produced gas there is mainly of secondary cracking retention oil.(3)Layout,drilling,completion(fracturing)and management of wells will be essential to achieve high productions in the shale gas production.(4)The existing main technologies have helped achieve efficient development of quality shale gas resources underground less than 3500 m in such national shale gas demonstration zones as ChangningeWeiyuan,Zhaotong,etc.Also,there shows a good potential of shale gas resources in those shallower strata and the strata with the burial depth of 3500-4000 m.In conclusion,with the help of continuous progress in technologies,an annual shale gas production rate of 40 billion cubic meters will be possibly achieved in this study area.展开更多
The use of exogenous carbon monoxide releasing molecules（CORMs）provides promise for clinical application;however,the hazard potential of CORMs in vivo remains poorly understood.The developmental toxicity of CORM-3 w...The use of exogenous carbon monoxide releasing molecules（CORMs）provides promise for clinical application;however,the hazard potential of CORMs in vivo remains poorly understood.The developmental toxicity of CORM-3 was investigated by exposure to concentrations ranging from 6.25 to400μmol/L during 4-144 h post fertilization.Toxicity endpoints of mortality,spontaneous movement,heart rate,hatching rate,malformation,body length,and larval behavior were measured.展开更多
The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which pr...The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which produces the feed-back inhibition effect in the hydrazine-promoted infectious development of silver halide.展开更多
Blood lead levels of 180 pupils from two elementary schools were determined and the intellec- tual development of the children was followed.The children in these two groups were similar in most nonlead variables.Resul...Blood lead levels of 180 pupils from two elementary schools were determined and the intellec- tual development of the children was followed.The children in these two groups were similar in most nonlead variables.Results showed that pupils at the school near a battery plant had higher blood lead levels than those at a school in a residential neighborhood.An evident dose- effect relationship between blood lead level and children's performance on psychological testing existed:the higher the blood level,the lower the intelligence quotient.This relationship re- mained after confounding factors were controlled by stepwise regression analysis.Partial regres- sion coefficients for PbB and verbal IQ,performance IQ,and full-scale IQ were -0.85,-0.71, and -0.91,respectively.1989 Academic Press,Inc.展开更多
We assessed genetic and environmental effectson bone development of the hand and wrist, andon key anthropometric measures in Chinese youngtwins. In total, 139 monozygotic and 95 dizygotictwin pairs aged from 5 to 18 y...We assessed genetic and environmental effectson bone development of the hand and wrist, andon key anthropometric measures in Chinese youngtwins. In total, 139 monozygotic and 95 dizygotictwin pairs aged from 5 to 18 years were recruited.The twin correlations of total hand and wrist scoresfor monozygotic （MZ） and dizygotic （DZ） twins were0.71 and 0.36, respectively. Bivariate modelanalysis showed moderate genetic correlations onlyfor total skeletal maturity vs. weight and totalskeletal maturity vs. waist circumference （r, 0.51and 0.46, respectively）. Our findings demonstratedthat genetic factors played important roles in bonedevelopment of the hand and wrist in Chineseyoung twins, and that these genetic effects mightbe distinct from those influencing anthropometricmeasures.展开更多
In the current education work, the most concerned about the moral education, because it has a strong influence, if we still stay in the traditional concept and standards, not only can not achieve ideal results, but al...In the current education work, the most concerned about the moral education, because it has a strong influence, if we still stay in the traditional concept and standards, not only can not achieve ideal results, but also may encounter many new problems. Objectively speaking, in carrying out moral work in the process of the secondary vocational school, the teacher in charge, to see their own problems, form the accurate cognition, take scientific and reasonable teaching means, strictly implement the global education to the task, and in the correct concept, standards organization daily teaching, the comprehensive progress of full preparation for the future. This paper mainly discusses the effective content of moral education work in secondary vocational school teachers, and puts forward some targeted measures, hoping to play a good help.展开更多
In college badminton teaching,teachers utilize the group cooperative learning method,which not only helps to improve students’badminton skill level but also cultivates their teamwork spirit,communication skills,and s...In college badminton teaching,teachers utilize the group cooperative learning method,which not only helps to improve students’badminton skill level but also cultivates their teamwork spirit,communication skills,and self-management ability unconsciously.In view of this,this paper mainly describes the significance of applying the group cooperative learning method in college badminton teaching,analyzes the current problems in college badminton teaching,and aims to discover effective development strategies for group cooperative learning method in college badminton teaching in order to improve the effectiveness of college badminton teaching.展开更多
1. The Role of Human Rights Education in Promoting Human Rights Development 1. Human rights education shapes the soft environment for human rights development
The reservoirs in the seventh member of the Triassic Yanchang Formation (Chang 7 Member) in the Qingcheng Oilfield of the Ordos Basin are characterized by thin sandbody, tight rocks, high heterogeneity, low formation ...The reservoirs in the seventh member of the Triassic Yanchang Formation (Chang 7 Member) in the Qingcheng Oilfield of the Ordos Basin are characterized by thin sandbody, tight rocks, high heterogeneity, low formation pressure coefficient, and complex geomorphology. Through the efforts in the stages of exploration, appraisal, pilot testing and development, a series of key technologies have been formed, including “sweet spot” optimization, differentiated three-dimensional well deployment, fast drilling and completion of large-cluster horizontal well, intensively-staged volume fracturing in long horizontal well, and optimization of rational production system. Furthermore, a production organization mode represented by factory-like operations on loess platform has been implemented. Application of these technologies has enabled to significantly improve the single-well production of the Qingcheng Oilfield, reduce the investment cost, and realize a large-scale and beneficial development at a full cost below $55 per barrel. In 2022, the annual production of Chang 7 shale oil in the Ordos Basin reached 221×10^(4) t, accounting for 70% of the annual shale oil production of China. The practice of development technologies in the Qingcheng Oilfield provides valuable references for efficient development of continental shale oil.展开更多
Based on the China Global Investment Tracker(CGIT)database of 2005-2018,this paper creates a country-sector-year panel set for a study on the BRI’s investment effects on the transportation sector of BRI countries usi...Based on the China Global Investment Tracker(CGIT)database of 2005-2018,this paper creates a country-sector-year panel set for a study on the BRI’s investment effects on the transportation sector of BRI countries using the difference-in-differencesin-differences(DDD)method.Our study finds that the BRI has significantly increased transportation investments by Chinese companies in the BRI countries without causing significant rise in problem transactions.The"debt trap"narrative that the BRI aims to take control over host countries’sovereign rights in exchange for debt write-offs is not supported by evidence.Discussions on sub-samples reveal that the BRI has mainly propelled SOEs in making transportation investments to generate development effects in host countries,most of which are Asian countries,and that the preferred mode of investment is cross-border M&As.展开更多
It is difficult to build an effective water flooding displacement pressure system in the middle section of a horizontal well in an ultra-low permeability sandstone reservoir.To solve this problem,this study proposes t...It is difficult to build an effective water flooding displacement pressure system in the middle section of a horizontal well in an ultra-low permeability sandstone reservoir.To solve this problem,this study proposes to use packers,sealing cannula and other tools in the same horizontal well to inject water in some fractures and produce oil from other fractures.This new energy supplement method forms a segmental synchronous injection-production system in a horizontal well.The method can reduce the distance between the injection end and the production end,and quickly establish an effective displacement system.Changing the displacement between wells to displacement between horizontal well sections,and point water flooding to linear uniform water flooding,the method can enhance water sweeping volume and shorten waterflooding response period.The research shows that:(1)In the synchronous injection and production of horizontal well in an ultra-low-permeability sandstone reservoir,the water injection section should select the section where the natural fractures and artificial fractures are in the same direction or the section with no natural fractures,and the space between two sections should be 60?80 m.(2)In addition to controlling injection pressure,periodic water injection can be taken to reduce the risk of re-opening and growth of natural fractures or formation fracture caused by the gradual increase of water injection pressure with water injection going on.(3)Field tests have verified that this method can effectively improve the output of single well and achieve good economic benefits,so it can be widely used in the development of ultra-low permeability sandstone reservoirs.展开更多
Tong's B-type water drive method was proposed as early as the 1970s and has been widely applied in the dynamic prediction and effective evaluation of oilfield development.Through extensive applications and studies...Tong's B-type water drive method was proposed as early as the 1970s and has been widely applied in the dynamic prediction and effective evaluation of oilfield development.Through extensive applications and studies,many researchers found that the statistical constants in the formula of the Tong's B-type water drive method(also referred to as the Tong's B-type formula)are not applicable to multiple types of reservoirs,especially low-permeability ones,due to the limited range of reservoir types when the formula was conceived.Moreover,they put forward suggestions to improve the Tong's B-type formula,most of which focused on the research and calculation of the first constant in the formula.For oilfields in the development stages of high or ultra-high water cuts,it is widely accepted that different types of reservoirs have different limit water cuts.This understanding naturally makes it necessary to further modify the Tong's B-type formula.It is practically significant to establish the water drive formula and cross plot considering that the two constants in the formula vary with reservoir type.By analyzing the derivation process and conditions of the Tong's B-type formula,this study points out two key problems,i.e.,the two constants 7.5 and 1.69 in the formula are not applicable to all types of reservoir.Given this,this study establishes a function between key reservoir parameters and the first constant and another function between key reservoir parameters and recovery efficiency.Based on the established two functions and considering that different types of oil reservoir have different limit water cuts,this study develops an improved Tong's B-type formula and prepares the corresponding improved cross plot.The results of this study will improve the applicability and accuracy of Tong's B-type water drive method in predicting the trend of water cut increasing for different types of oil reservoirs.展开更多
基金financially supported by grants for the National Natural Science Foundation of China(31370431)to JFCthe Sichuan Provincial Science and Technology Department(2018JY0617)to JFCthe Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment,China(2019HJ2096001006)to JFC。
文摘How nutritional conditions during early development affect an organism’s phenotype at adulthood is still poorly understood despite a plethora of research on developmental plasticity.The"environmental matching"hypothesis predicts that individuals will have high fitness providing that their adult environment"matches"what they experienced during development.In contrast,the"silver spoon"hypothesis predicts that individuals who obtain better developmental resources will be generally superior.Here we tested these two hypotheses and examined the underlying hormonal mechanisms by manipulating the early dietary protein content of African clawed frogs(Xenopus laevis)for a year with a 2×2 factorial experimental design.We found that only a lowprotein food during development enhanced the vocal competition ability of male X.laevis,and that vocal dominance was associated with higher cortisol levels but not related with testosterone content.These results were not congruent with the"environmental matching"hypothesis or with the"silver spoon"hypothesis,suggesting the behavioral plasticity during development is more complex than our expectation in amphibians.
基金The authors gratefully acknowledge the financial support from the National Science and Technology Major Project of China(Grant Nos.2017ZX05013-001 and 2017ZX05069-003).
文摘Given its relevance to the exploitation of ultra-low permeability reservoirs,which account for a substantial proportion of the world’s exploited and still unexploited reserves,in the present study the development of an adequate water injection system is considered.Due to the poor properties and weak seepage capacity of these reservoirs,the water injection pressure typically increases continuously during water flooding.In this research,the impact on such a process of factors as permeability,row spacing,and pressure gradient is evaluated experimentally using a high-pressure large-scale outcrop model.On this basis,a comprehensive evaluation coefficient is introduced able to account for the effective driving pressure.
文摘The dynamics of blood lead (Pb-B) and blood zinc protoporphyrin (ZPP-B) of women in early pregnancy and parturient women with lead exposure and the effects on fetus development were investigated. Pb-B of lead-exposed women was high: 0.984 μmol/L (20.38 μg/dl) and ZPP was 84.52μg/dl. Cord blood Pb-B was 0.896 μmol/L(18.56μg/dl)and cord blood ZPP was 69.24μg/dl. In the control group, Pb-B was 0.261μmol/L(5.41μg/dl), ZPP-B, 37.59 μg/dl, cord blood, Pb-B 0.34 μmol/L (7.93 μg/dl), and cord ZPP-B 49.0μg/dl. There was a significant correlation between blood lead and blood ZPP, maternal Pb-B and cord Pb-B, maternal Pb-B and cord ZPP-B. The significance of the consistency of high level Pb-B and the effects on fetus development is discussed.
文摘X oilfield is located in Bohai Sea area, in which G oil formation is a typical drape anticline structure, which is composed of multiple sets of thick sandy conglomerate and multiple sets of argillaceous intercalation. From the perspective of development effect, muddy interlayer has a great impact on the oilfield. In this paper, through core identification and well logging identification, the electrical discrimination standard is summarized to identify the interlayer. Through statistics and analysis of the production performance of actual wells, the influence of muddy interlayer on the development performance of oil wells is summarized. This study provides guidance for the development of strong bottom water reservoirs with interlayer.
文摘Oil field waterflooding is a complex man-controlled systematic behavior, and the related evaluation methods vary greatly. This paper put forward a fuzzy comprehensive method of evaluating controlled development level by analysis of the macroscopic evaluation to oil field waterflooding effect with combination of original reservoir geological state. This fuzzy evaluation technique bears unique advantages because there is little difference among evaluation indexes which represent the dynamic and static state of regional neighborhood of development units (blocks, Production Company<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> etc.). Not only the mathematical method for evaluating oil field waterflooding effect is set up, but also the method is applied in three blocks of D oil field. The calculated results show the effectiveness and practicability of the method.</span></span></span>
文摘Shale gas is a practical resource with great potential that could be economically explored and developed in the near future. It has been commercially developed in North America and other places. Featuring a vast distribution, a low abundance,unfavorable reservoir conditions, ultra-low permeability and a fast production decline, shale gas is more difficult to develop than conventional natural gas, as it needs advanced drilling and completion technology to develop. During the early stage of shale gas exploration and development, the United States offered enterprises necessary incentives such as tax reductions and exemptions and subsidies to achieve sustainable shale gas development and encourage technological progresses. By comparing the state of China's shale gas development with that of the US' in terms of geological conditions, production technology,market price, tax relief, subsidy periods and amount, this paper intends to put forward related suggestions for the effective development of shale gas according to the current status of development.
基金Project supported by China Academy of Engineering Strategic Consulting Key Research Project“Study on Effective Development Path of China’s Shale Gas Scale”(No.:2018-XZ-032)National Major Science and Technology Project“Large Oil and Gas Field and CBM Development-Changning-Weiyuan Shale Gas Development of Demonstration Project”(No.:2016ZX05062-002)PetroChina Major Project“Research and Application of Key Technologies for Producing 30 Billion Cm of Natural Gas in Southwest Oil and Gas Fields”(No.:2016E-0611).
文摘Based on the newest understandings of geological assessment and new progresses in engineering technologies in the development of shale gas rich in the southern Sichuan Basin,this paper analyzed the shale gas enrichment laws and the key factors of its commercial production,discussed the scale and efficient development modes,and clarified the further developing orientation.The following findings were concluded.(1)The Lower Silurian Longmaxi shale is the sweetest spot in this study area with a low density and a high uranium/thorium(U/Th)ratio,TOC content,quartz content,and free gas content.Besides,its distribution laws are mainly controlled by the sedimentary facies of deep water shelf.(2)The overpressured zones away from the ancient(present)erosion zones and large faults,mainly controlled by multi-stage tectonic evolution,belong to the most favorable sweet spots not only because there are well-developed organic matters and pores but the produced gas there is mainly of secondary cracking retention oil.(3)Layout,drilling,completion(fracturing)and management of wells will be essential to achieve high productions in the shale gas production.(4)The existing main technologies have helped achieve efficient development of quality shale gas resources underground less than 3500 m in such national shale gas demonstration zones as ChangningeWeiyuan,Zhaotong,etc.Also,there shows a good potential of shale gas resources in those shallower strata and the strata with the burial depth of 3500-4000 m.In conclusion,with the help of continuous progress in technologies,an annual shale gas production rate of 40 billion cubic meters will be possibly achieved in this study area.
基金supported by National Basic Research Program of China(2010CB834202)the National Natural Science Foundation of China(11305226,11175222)+1 种基金the Scientific Technology Research Projects of Lanzhou City(2015-3-75)the Western Talent Program of Chinese Academy of Sciences(Y460030XB0)
文摘The use of exogenous carbon monoxide releasing molecules（CORMs）provides promise for clinical application;however,the hazard potential of CORMs in vivo remains poorly understood.The developmental toxicity of CORM-3 was investigated by exposure to concentrations ranging from 6.25 to400μmol/L during 4-144 h post fertilization.Toxicity endpoints of mortality,spontaneous movement,heart rate,hatching rate,malformation,body length,and larval behavior were measured.
文摘The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which produces the feed-back inhibition effect in the hydrazine-promoted infectious development of silver halide.
文摘Blood lead levels of 180 pupils from two elementary schools were determined and the intellec- tual development of the children was followed.The children in these two groups were similar in most nonlead variables.Results showed that pupils at the school near a battery plant had higher blood lead levels than those at a school in a residential neighborhood.An evident dose- effect relationship between blood lead level and children's performance on psychological testing existed:the higher the blood level,the lower the intelligence quotient.This relationship re- mained after confounding factors were controlled by stepwise regression analysis.Partial regres- sion coefficients for PbB and verbal IQ,performance IQ,and full-scale IQ were -0.85,-0.71, and -0.91,respectively.1989 Academic Press,Inc.
文摘We assessed genetic and environmental effectson bone development of the hand and wrist, andon key anthropometric measures in Chinese youngtwins. In total, 139 monozygotic and 95 dizygotictwin pairs aged from 5 to 18 years were recruited.The twin correlations of total hand and wrist scoresfor monozygotic （MZ） and dizygotic （DZ） twins were0.71 and 0.36, respectively. Bivariate modelanalysis showed moderate genetic correlations onlyfor total skeletal maturity vs. weight and totalskeletal maturity vs. waist circumference （r, 0.51and 0.46, respectively）. Our findings demonstratedthat genetic factors played important roles in bonedevelopment of the hand and wrist in Chineseyoung twins, and that these genetic effects mightbe distinct from those influencing anthropometricmeasures.
文摘In the current education work, the most concerned about the moral education, because it has a strong influence, if we still stay in the traditional concept and standards, not only can not achieve ideal results, but also may encounter many new problems. Objectively speaking, in carrying out moral work in the process of the secondary vocational school, the teacher in charge, to see their own problems, form the accurate cognition, take scientific and reasonable teaching means, strictly implement the global education to the task, and in the correct concept, standards organization daily teaching, the comprehensive progress of full preparation for the future. This paper mainly discusses the effective content of moral education work in secondary vocational school teachers, and puts forward some targeted measures, hoping to play a good help.
文摘In college badminton teaching,teachers utilize the group cooperative learning method,which not only helps to improve students’badminton skill level but also cultivates their teamwork spirit,communication skills,and self-management ability unconsciously.In view of this,this paper mainly describes the significance of applying the group cooperative learning method in college badminton teaching,analyzes the current problems in college badminton teaching,and aims to discover effective development strategies for group cooperative learning method in college badminton teaching in order to improve the effectiveness of college badminton teaching.
文摘1. The Role of Human Rights Education in Promoting Human Rights Development 1. Human rights education shapes the soft environment for human rights development
基金Supported by the PetroChina Science and Technology Major Project(2021DJ1806,2023ZZ15).
文摘The reservoirs in the seventh member of the Triassic Yanchang Formation (Chang 7 Member) in the Qingcheng Oilfield of the Ordos Basin are characterized by thin sandbody, tight rocks, high heterogeneity, low formation pressure coefficient, and complex geomorphology. Through the efforts in the stages of exploration, appraisal, pilot testing and development, a series of key technologies have been formed, including “sweet spot” optimization, differentiated three-dimensional well deployment, fast drilling and completion of large-cluster horizontal well, intensively-staged volume fracturing in long horizontal well, and optimization of rational production system. Furthermore, a production organization mode represented by factory-like operations on loess platform has been implemented. Application of these technologies has enabled to significantly improve the single-well production of the Qingcheng Oilfield, reduce the investment cost, and realize a large-scale and beneficial development at a full cost below $55 per barrel. In 2022, the annual production of Chang 7 shale oil in the Ordos Basin reached 221×10^(4) t, accounting for 70% of the annual shale oil production of China. The practice of development technologies in the Qingcheng Oilfield provides valuable references for efficient development of continental shale oil.
基金supported by the National Natural Science Foundation of China(NSFC)Youth Program“Study on the Diffusion Mechanism and Policy Effects of Local Environmental Management Policies:an Example of the‘River Chief System’”(Grant No.:71903085)the National Social Science Foundation of China Key Research Program“Study on BRI Trade and Investment Liberalization and Facilitation:Quantitative Evaluation and Implementation Strategies”(Grant No.:18VDL014)”the National Social Science Foundation of China Key Program“Study on China’s Economic Growth Potentials and Drivers”(Grant No.:14ZDA023)。
文摘Based on the China Global Investment Tracker(CGIT)database of 2005-2018,this paper creates a country-sector-year panel set for a study on the BRI’s investment effects on the transportation sector of BRI countries using the difference-in-differencesin-differences(DDD)method.Our study finds that the BRI has significantly increased transportation investments by Chinese companies in the BRI countries without causing significant rise in problem transactions.The"debt trap"narrative that the BRI aims to take control over host countries’sovereign rights in exchange for debt write-offs is not supported by evidence.Discussions on sub-samples reveal that the BRI has mainly propelled SOEs in making transportation investments to generate development effects in host countries,most of which are Asian countries,and that the preferred mode of investment is cross-border M&As.
基金Supported by the China National Science and Technology Major Project(2016ZX05050)
文摘It is difficult to build an effective water flooding displacement pressure system in the middle section of a horizontal well in an ultra-low permeability sandstone reservoir.To solve this problem,this study proposes to use packers,sealing cannula and other tools in the same horizontal well to inject water in some fractures and produce oil from other fractures.This new energy supplement method forms a segmental synchronous injection-production system in a horizontal well.The method can reduce the distance between the injection end and the production end,and quickly establish an effective displacement system.Changing the displacement between wells to displacement between horizontal well sections,and point water flooding to linear uniform water flooding,the method can enhance water sweeping volume and shorten waterflooding response period.The research shows that:(1)In the synchronous injection and production of horizontal well in an ultra-low-permeability sandstone reservoir,the water injection section should select the section where the natural fractures and artificial fractures are in the same direction or the section with no natural fractures,and the space between two sections should be 60?80 m.(2)In addition to controlling injection pressure,periodic water injection can be taken to reduce the risk of re-opening and growth of natural fractures or formation fracture caused by the gradual increase of water injection pressure with water injection going on.(3)Field tests have verified that this method can effectively improve the output of single well and achieve good economic benefits,so it can be widely used in the development of ultra-low permeability sandstone reservoirs.
文摘Tong's B-type water drive method was proposed as early as the 1970s and has been widely applied in the dynamic prediction and effective evaluation of oilfield development.Through extensive applications and studies,many researchers found that the statistical constants in the formula of the Tong's B-type water drive method(also referred to as the Tong's B-type formula)are not applicable to multiple types of reservoirs,especially low-permeability ones,due to the limited range of reservoir types when the formula was conceived.Moreover,they put forward suggestions to improve the Tong's B-type formula,most of which focused on the research and calculation of the first constant in the formula.For oilfields in the development stages of high or ultra-high water cuts,it is widely accepted that different types of reservoirs have different limit water cuts.This understanding naturally makes it necessary to further modify the Tong's B-type formula.It is practically significant to establish the water drive formula and cross plot considering that the two constants in the formula vary with reservoir type.By analyzing the derivation process and conditions of the Tong's B-type formula,this study points out two key problems,i.e.,the two constants 7.5 and 1.69 in the formula are not applicable to all types of reservoir.Given this,this study establishes a function between key reservoir parameters and the first constant and another function between key reservoir parameters and recovery efficiency.Based on the established two functions and considering that different types of oil reservoir have different limit water cuts,this study develops an improved Tong's B-type formula and prepares the corresponding improved cross plot.The results of this study will improve the applicability and accuracy of Tong's B-type water drive method in predicting the trend of water cut increasing for different types of oil reservoirs.
