Self-assembly of metal halide perovskite nanocrystals(NCs)into superlattices can exhibit unique collective properties,which have significant application values in the display,detector,and solar cell field.This review ...Self-assembly of metal halide perovskite nanocrystals(NCs)into superlattices can exhibit unique collective properties,which have significant application values in the display,detector,and solar cell field.This review discusses the driving forces behind the self-assembly process of perovskite NCs,and the commonly used self-assembly methods and different self-assembly structures are detailed.Subsequently,we summarize the collective optoelectronic properties and application areas of perovskite superlattice structures.Finally,we conclude with an outlook on the potential issues and future challenges in developing perovskite NCs.展开更多
Based on satellite remote sensing TM/ETM+ images of Xuzhou city,land use forms of the city in 1987,1994 and 2000 were extracted by using a neural network classification method. The expansion contribution rate and annu...Based on satellite remote sensing TM/ETM+ images of Xuzhou city,land use forms of the city in 1987,1994 and 2000 were extracted by using a neural network classification method. The expansion contribution rate and annual expansion intensity index of each administrative district have been calculated and the contribution rate matrices and spatial distribution maps of land use changes were obtained. Based on the above analysis,the characteristics of urban expansion from 1987 to 2000 have been explored. From 1987 to 1994,the expansion contribution rate of Quanshan dis-trict reached 46.80%,the highest in all administrative districts of Xuzhou city; Tongshan town was in a high-speed ex-pansion period; both Quanshan and Yunlong districts were experiencing fast-speed expansion periods while the entire city was expanding at a medium-speed with an annual expansion intensity index of 0.98; the city spread eastwards and southwards. From 1994 to 2000,the expansion contribution rate of Quanshan district reached 43.67%,the highest in Xuzhou; the entire city was in a medium-speed expansion period with an annual expansion intensity index of 1.04; the city has rapidly been extended towards the southeast. According to the contribution rate matrices of land use changes,urban expansion mainly usurps cropland and woodland. A quantitative analysis found that population growth,indus-trialization and economic development are the primary driving forces behind urban expansion.展开更多
Fires are an important factor impacting forest ecosystems of Daxing'anling and have a significant effect on soil microbial community structure.In this study,highthroughput sequencing for 16 S rDNA and ITS rDNA wer...Fires are an important factor impacting forest ecosystems of Daxing'anling and have a significant effect on soil microbial community structure.In this study,highthroughput sequencing for 16 S rDNA and ITS rDNA were applied to analyze the changing characteristics and driving factors of bacterial and fungal community structures in burned areas with different fire severity.PICRUSt2 software was used to predict the functional characteristics of burned areas with different fire severity.The purpose was to unveil the responsive relationships among the structure and function of bacterial and fungal communities,fire severity,and post-disturbance restoration times.After high severity fires,the destruction of surface vegetation and loss of soil nutrients reduced the diversity and abundance of soil bacteria and fungi.The soil bacteria community structure,which was dominated by Acidobacteria,Proteobacteria,and Actinobacteria,changed to be dominated by Proteobacteria and Chloroflexi.As well,soil fungal community changed from domination by Helotiales,Eurotiales and Russulales to domination by Archaeorhizomycetales and Helotiales.Over time,soil bacterial community was gradually restored to prefire levels 30 years after the fire.Soil fungal community changed and failed to restore to pre-fire levels after 30 years.After low/intermediate severity fires,environmental factors were relatively unchanged so that soil bacteria diversity and abundance increased,optimizing community composition.The diversity and abundance of soil fungi decreased and the community structure changed slightly.Over time,both bacterial and fungal communities were gradually restored to pre-fire levels 30 years after the fire.After fire disturbance,with increasing severity,soil carbon fixation,lignin degradation,mineralization of organic nitrogen and hydrolysis of organic phosphorus are enhanced.Denitrification is weakened.Therefore,forest fires have certain positive effects on carbon,nitrogen and phosphorus cycles where soil bacteria and fungi are involved.展开更多
A good deal of studies have proven that effective exciton dissociation and fast hole transport can operate efficiently in non-fullerene organic photovoltaics(OPVs)despite nearly zero driving force.Even so,whether such...A good deal of studies have proven that effective exciton dissociation and fast hole transport can operate efficiently in non-fullerene organic photovoltaics(OPVs)despite nearly zero driving force.Even so,whether such a phenomenon is universal and how small the driving force can realize the best photovoltaic performance still require a thorough understanding.Herein,despite the zero driving force based on PM6:F8IC system,a maximum short-circuit current(J_(sc))of 23.0 mA/cm^(2) and high power conversion efficiency(PCE)of 12.2%can still be achieved.Due to the continuously adjustable energy levels can be realized in organic semiconducting alloys including F8IC:IT-4F and F8IC:Y6,the suitable third components can play the role of energy level regulator.Therefore,the HOMO energy level offset(DEHOMO(D A))from zero to 0.07 and 0.06 eV is accomplished in the optimized IT-4F and Y6 ternary devices.Consequently,both ternary devices achieved substantially increased PCE of 13.8%and Jsc of 24.4 and 25.2 mA/cm^(2),respectively.Besides,pseudo-planar heterojunction(PPHJ)devices based on alloyed acceptors through sequential spin-coating method further improve the photovoltaic performance.Our work puts forward the concept of energy level regulator and prove that the ternary alloy strategy has unique advantages and huge research potential in continuously adjusting the driving force.展开更多
To thoroughly understand the dynamic mechanism of hydrocarbon expulsion from deep source rocks,in this study,five types of hydrocarbon expulsion dynamics(thermal expansion,hydrocarbon diffusion,compaction,product volu...To thoroughly understand the dynamic mechanism of hydrocarbon expulsion from deep source rocks,in this study,five types of hydrocarbon expulsion dynamics(thermal expansion,hydrocarbon diffusion,compaction,product volume expansion,and capillary pressure difference(CPD))are studied.A model is proposed herein to evaluate the relative contribution of different dynamics for hydrocarbon expulsion using the principle of mass balance,and the model has been applied to the Cambrian source rocks in the Tarim Basin.The evaluation results show that during hydrocarbon expulsion from the source rocks,the relative contribution of CPD is the largest(>50%),followed by compaction(10%-40%),product volume expansion(5%-30%),and thermal expansion(2%-20%).The relative contribution of diffusion to hydrocarbon expulsion is minimal(<10%).These results demonstrate that CPD plays an important role in the hydrocarbon expulsion process of deep source rocks.The hydrocarbon expulsion process of source rocks can be categorized into three stages based on the contribution of different dynamics to the process:the first stage is dominated by compaction and diffusion to expel hydrocarbons,the second stage is dominated by product volume expansion and CPD,and the third stage is dominated by product volume expansion and CPD.This research offers new insights into hydrocarbon exploration in tight oil and gas reservoirs.展开更多
The year of 2017 saw an obvious improvement in the sector of China’s textile machinery industry and an increase of the main business income and gross profit.Besides,foreign trade in textile machinery products grew in...The year of 2017 saw an obvious improvement in the sector of China’s textile machinery industry and an increase of the main business income and gross profit.Besides,foreign trade in textile machinery products grew in number.展开更多
According to the 2017 Summary Conference of China National Textile and Apparel Council(CNTAC)held on January 22nd to 23rd,in the first 11 months of 2017,the overall operation of China’s textile industry showed a stea...According to the 2017 Summary Conference of China National Textile and Apparel Council(CNTAC)held on January 22nd to 23rd,in the first 11 months of 2017,the overall operation of China’s textile industry showed a steady growth rate,stable domestic demand growth。展开更多
It was during the weekend that Miss Wu lover a shop selling the luxury brand Louis VThrough the window, she could indulged in the filled with all kinds of handbags, dustcoats anheels-all she yearned for. But she tarri...It was during the weekend that Miss Wu lover a shop selling the luxury brand Louis VThrough the window, she could indulged in the filled with all kinds of handbags, dustcoats anheels-all she yearned for. But she tarried on thand found herself embarrassed to enter.展开更多
Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and str...Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and structural stability that limit the performance.The core-shell semiconductorgraphene(CSSG)nanoarchitectures may address these issues due to their unique structures with exceptional physical and chemical properties.This review explores recent advances of the CSSG nanoarchitectures in the photocatalytic performance.It starts with the classification of the CSSG nanoarchitectures by the dimensionality.Then,the construction methods under internal and external driving forces were introduced and compared with each other.Afterward,the physicochemical properties and photocatalytic applications of these nanoarchitectures were discussed,with a focus on their role in photocatalysis.It ends with a summary and some perspectives on future development of the CSSG nanoarchitectures toward highly efficient photocatalysts with extensive application.By harnessing the synergistic capabilities of the CSSG architectures,we aim to address pressing environmental and energy challenges and drive scientific progress in these fields.展开更多
Overpressure is a key factor for oil and gas charging in tight reservoirs,but it is still a challenge to evaluate the overpressure evolution and its control on oil and gas charging.Taking Xujiahe Formation in the nort...Overpressure is a key factor for oil and gas charging in tight reservoirs,but it is still a challenge to evaluate the overpressure evolution and its control on oil and gas charging.Taking Xujiahe Formation in the northeastern Sichuan Basin as an example,this paper presented a method for evaluating overpressure and its effect on natural gas charging in tight sandstone in compressional basin.The abnormally high pressure and its causes were analyzed by measured data and logging evaluation.Theoretical calculation and PVT simulation were used to investigate the amounts of overpressure resulted from hydrocarbon generation and tecto nic compression,respectively.Then the source rock-reservoir pressu re differences were calculated and the characteristics of natural gas charging during the natural gas charging periods were analyzed.It was revealed that hydrocarbon generation and tectonic compression were the main causes of the overpressure.The overpressure of both source rocks and reservoir exhibited a gradually increasing trend from Middle Jurassic to Early Cretaceous(J2-K1),then decreased since Later Cretaceous(K2),and some of that preserved to now.The contributions of the hydrocarbon generation and tectonic compression to overpressure were different in different periods.The residual pressure difference between the source rocks and the reservoir is the major driving force for tight sandstone gas charging.The main hydrocarbon generating area of the source rocks and the area of high driving force were major natural gas enrichment areas,and the driving force determined the natural gas charging space in the pore throat system of the reservoir.This research helps evaluate the overpressure and pressure difference between source rocks and reservoir in compressed basin,as well as investigate the effective pore throat space of tight gas charging by the driver of overpressure.展开更多
The origin of overpressure and its effect on petroleum accumulation in the large Permian/Triassic conglomerate oil province in the Mahu Sag,Junggar Basin have been investigated based on comprehensive analysis of log c...The origin of overpressure and its effect on petroleum accumulation in the large Permian/Triassic conglomerate oil province in the Mahu Sag,Junggar Basin have been investigated based on comprehensive analysis of log curve combinations,loading-unloading curves,sonic velocity-density cross-plot,and porosity comparison data.The study results show that there are two kinds of normal compaction models in the study area,namely,two-stage linear model and exponent model;overpressure in the large conglomerate reservoirs including Lower Triassic Baikouquan Formation and Permian Upper and Lower Wu’erhe Formations is the result of pressure transfer,and the source of overpressure is the overpressure caused by hydrocarbon generation of Permian Fengcheng Formation major source rock.The petroleum migrated through faults under the driving of hydrocarbon generation overpressure into the reservoirs to accumulate,forming the Permian and Triassic overpressure oil and gas reservoirs.The occurrence and distribution of overpressure are controlled by the source rock maturity and strike-slip faults connecting the source rock and conglomerate reservoirs formed from Indosinian Movement to Himalayan Movement.As overpressure is the driving force for petroleum migration in the large Mahu oil province,the formation and distribution of petroleum reservoirs above the source rock in this area may have a close relationship with the occurrence of overpressure.展开更多
As more and more farmland is converted to forestry, the need for effective decision support regarding the use of land in the fragile ecological environment of the Loess Plateau hilly-gully area. The Luoyugou watershed...As more and more farmland is converted to forestry, the need for effective decision support regarding the use of land in the fragile ecological environment of the Loess Plateau hilly-gully area. The Luoyugou watershed was chosen as the study area to calculate the single dynamic degree, integrated dynamic degree, and change indexes of land use, as well as the land-use type transition matrix. This was done by interpreting the TM and SPOT images of the Luoyugou watershed in 1986, 1995, and2004 and making statistical analysis. The results of ou statistical analysis show that the conversion of slope farm land to terrace and forest land plays a dominant role in land-use changes in the Luoyugou watershed from 1986 to2004. The land-use changes are mainly driven by popula tion growth, socio-economic development, consume spending, and investment in forest ecology.展开更多
A bidisperse model for transient diffusion and adsorption processes in porous materials is presented in this paper.The mathematical model is solved by numerical methods based on finite elements combined with the linea...A bidisperse model for transient diffusion and adsorption processes in porous materials is presented in this paper.The mathematical model is solved by numerical methods based on finite elements combined with the linear driving force approximation.A criterion based on the model to identify the diffusion controlling mechanism(macropore diffusion,micropore diffusion,or both)is proposed.The effects of different adsorption isotherms(linear,Freundlich,or Langmuir)on the concentration profiles and on curves of fractional uptake versus time are investigated.In addition,the influences of model parameters concerning the pore networks on the fractional uptake are studied as well.展开更多
Three small bandgap non-fullerene(SBG NFAs) acceptors,BDTI,BDTI-2 F and BDTI-4 F,based on a carbon-oxygen bridged central core and thieno[3,4-b]thiophene linker,end-capped with varied electronwithdrawing terminal grou...Three small bandgap non-fullerene(SBG NFAs) acceptors,BDTI,BDTI-2 F and BDTI-4 F,based on a carbon-oxygen bridged central core and thieno[3,4-b]thiophene linker,end-capped with varied electronwithdrawing terminal groups,were designed and synthesized.The acceptors exhibit strong absorption from 600 nm to 1000 nm.The optimal device incorporating designed NFA and PTB7-Th polymer donor achieves a power conversion efficiency of 9.11% with near 0 eV HOMO offset.The work presents a case study of efficient non-fullerene solar cells with small HOMO offsets,which is achieved by blending PTB7-Th with fine-tuned SBG acceptor.展开更多
In this paper, the evacuation dynamics in an artificial room with only one exit is investigated via experiments and modeling. Two sets of experiments are implemented, in which pedestrians are asked to escape individua...In this paper, the evacuation dynamics in an artificial room with only one exit is investigated via experiments and modeling. Two sets of experiments are implemented, in which pedestrians are asked to escape individually. It is found that the average evacuation time gap is essentially constant. To model the evacuation dynamics, an improved social force model is proposed, in which it is assumed that the driving force of a pedestrian cannot be performed when the resultant physical force exceeds a threshold. Simulation results are in good agreement with the experimental ones.展开更多
基金financially supported by the National Key Research and Development Program of China (2021YFB3600403)the Fundamental Research Funds for the Central Universities (000-0903069032)。
文摘Self-assembly of metal halide perovskite nanocrystals(NCs)into superlattices can exhibit unique collective properties,which have significant application values in the display,detector,and solar cell field.This review discusses the driving forces behind the self-assembly process of perovskite NCs,and the commonly used self-assembly methods and different self-assembly structures are detailed.Subsequently,we summarize the collective optoelectronic properties and application areas of perovskite superlattice structures.Finally,we conclude with an outlook on the potential issues and future challenges in developing perovskite NCs.
基金Projects 40401038 supported by the National Natural Science Foundation of China05KJB420133 by the Natural Science Foundation for Colleges and Universities in Jiangsu Province
文摘Based on satellite remote sensing TM/ETM+ images of Xuzhou city,land use forms of the city in 1987,1994 and 2000 were extracted by using a neural network classification method. The expansion contribution rate and annual expansion intensity index of each administrative district have been calculated and the contribution rate matrices and spatial distribution maps of land use changes were obtained. Based on the above analysis,the characteristics of urban expansion from 1987 to 2000 have been explored. From 1987 to 1994,the expansion contribution rate of Quanshan dis-trict reached 46.80%,the highest in all administrative districts of Xuzhou city; Tongshan town was in a high-speed ex-pansion period; both Quanshan and Yunlong districts were experiencing fast-speed expansion periods while the entire city was expanding at a medium-speed with an annual expansion intensity index of 0.98; the city spread eastwards and southwards. From 1994 to 2000,the expansion contribution rate of Quanshan district reached 43.67%,the highest in Xuzhou; the entire city was in a medium-speed expansion period with an annual expansion intensity index of 1.04; the city has rapidly been extended towards the southeast. According to the contribution rate matrices of land use changes,urban expansion mainly usurps cropland and woodland. A quantitative analysis found that population growth,indus-trialization and economic development are the primary driving forces behind urban expansion.
基金funded by the National Key Research and Development Program of China (Grant No.2017 YFC0504003)Inner Mongolia Natural Science Foundation(No.2018MS03049)Young Teacher Research Fund Project of Forestry College of Inner Mongolia Agricultural University。
文摘Fires are an important factor impacting forest ecosystems of Daxing'anling and have a significant effect on soil microbial community structure.In this study,highthroughput sequencing for 16 S rDNA and ITS rDNA were applied to analyze the changing characteristics and driving factors of bacterial and fungal community structures in burned areas with different fire severity.PICRUSt2 software was used to predict the functional characteristics of burned areas with different fire severity.The purpose was to unveil the responsive relationships among the structure and function of bacterial and fungal communities,fire severity,and post-disturbance restoration times.After high severity fires,the destruction of surface vegetation and loss of soil nutrients reduced the diversity and abundance of soil bacteria and fungi.The soil bacteria community structure,which was dominated by Acidobacteria,Proteobacteria,and Actinobacteria,changed to be dominated by Proteobacteria and Chloroflexi.As well,soil fungal community changed from domination by Helotiales,Eurotiales and Russulales to domination by Archaeorhizomycetales and Helotiales.Over time,soil bacterial community was gradually restored to prefire levels 30 years after the fire.Soil fungal community changed and failed to restore to pre-fire levels after 30 years.After low/intermediate severity fires,environmental factors were relatively unchanged so that soil bacteria diversity and abundance increased,optimizing community composition.The diversity and abundance of soil fungi decreased and the community structure changed slightly.Over time,both bacterial and fungal communities were gradually restored to pre-fire levels 30 years after the fire.After fire disturbance,with increasing severity,soil carbon fixation,lignin degradation,mineralization of organic nitrogen and hydrolysis of organic phosphorus are enhanced.Denitrification is weakened.Therefore,forest fires have certain positive effects on carbon,nitrogen and phosphorus cycles where soil bacteria and fungi are involved.
基金support the National Natural Science Foundation of China(NSFC)(51973032,and 21905043)support from the National Natural Science Foundation of China(NSFC)(51833004)financial support by the National Key Research and Development Program of China(2017YFA0207700)。
文摘A good deal of studies have proven that effective exciton dissociation and fast hole transport can operate efficiently in non-fullerene organic photovoltaics(OPVs)despite nearly zero driving force.Even so,whether such a phenomenon is universal and how small the driving force can realize the best photovoltaic performance still require a thorough understanding.Herein,despite the zero driving force based on PM6:F8IC system,a maximum short-circuit current(J_(sc))of 23.0 mA/cm^(2) and high power conversion efficiency(PCE)of 12.2%can still be achieved.Due to the continuously adjustable energy levels can be realized in organic semiconducting alloys including F8IC:IT-4F and F8IC:Y6,the suitable third components can play the role of energy level regulator.Therefore,the HOMO energy level offset(DEHOMO(D A))from zero to 0.07 and 0.06 eV is accomplished in the optimized IT-4F and Y6 ternary devices.Consequently,both ternary devices achieved substantially increased PCE of 13.8%and Jsc of 24.4 and 25.2 mA/cm^(2),respectively.Besides,pseudo-planar heterojunction(PPHJ)devices based on alloyed acceptors through sequential spin-coating method further improve the photovoltaic performance.Our work puts forward the concept of energy level regulator and prove that the ternary alloy strategy has unique advantages and huge research potential in continuously adjusting the driving force.
基金This study is financially supported by the Joint Fund of the National Natural Science Foundation of China under grant number U19B6003-02-04the Science Foundation of China University of Petroleum,Beijing,under grant number 2462020BJRC005 and 2462022YXZZ007+1 种基金the National Natural Science Foundation of China under grant number 42102145the China National Petroleum Corporation's"14th Five-Year Plan"major scientific projecs under grant number 2021DJ0101.
文摘To thoroughly understand the dynamic mechanism of hydrocarbon expulsion from deep source rocks,in this study,five types of hydrocarbon expulsion dynamics(thermal expansion,hydrocarbon diffusion,compaction,product volume expansion,and capillary pressure difference(CPD))are studied.A model is proposed herein to evaluate the relative contribution of different dynamics for hydrocarbon expulsion using the principle of mass balance,and the model has been applied to the Cambrian source rocks in the Tarim Basin.The evaluation results show that during hydrocarbon expulsion from the source rocks,the relative contribution of CPD is the largest(>50%),followed by compaction(10%-40%),product volume expansion(5%-30%),and thermal expansion(2%-20%).The relative contribution of diffusion to hydrocarbon expulsion is minimal(<10%).These results demonstrate that CPD plays an important role in the hydrocarbon expulsion process of deep source rocks.The hydrocarbon expulsion process of source rocks can be categorized into three stages based on the contribution of different dynamics to the process:the first stage is dominated by compaction and diffusion to expel hydrocarbons,the second stage is dominated by product volume expansion and CPD,and the third stage is dominated by product volume expansion and CPD.This research offers new insights into hydrocarbon exploration in tight oil and gas reservoirs.
文摘The year of 2017 saw an obvious improvement in the sector of China’s textile machinery industry and an increase of the main business income and gross profit.Besides,foreign trade in textile machinery products grew in number.
文摘According to the 2017 Summary Conference of China National Textile and Apparel Council(CNTAC)held on January 22nd to 23rd,in the first 11 months of 2017,the overall operation of China’s textile industry showed a steady growth rate,stable domestic demand growth。
文摘It was during the weekend that Miss Wu lover a shop selling the luxury brand Louis VThrough the window, she could indulged in the filled with all kinds of handbags, dustcoats anheels-all she yearned for. But she tarried on thand found herself embarrassed to enter.
基金supported by the National Natural Science Foundation of China(61974125)the Open Innovation Fund for undergraduate students of Xiamen University(KFJJ-202411).
文摘Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and structural stability that limit the performance.The core-shell semiconductorgraphene(CSSG)nanoarchitectures may address these issues due to their unique structures with exceptional physical and chemical properties.This review explores recent advances of the CSSG nanoarchitectures in the photocatalytic performance.It starts with the classification of the CSSG nanoarchitectures by the dimensionality.Then,the construction methods under internal and external driving forces were introduced and compared with each other.Afterward,the physicochemical properties and photocatalytic applications of these nanoarchitectures were discussed,with a focus on their role in photocatalysis.It ends with a summary and some perspectives on future development of the CSSG nanoarchitectures toward highly efficient photocatalysts with extensive application.By harnessing the synergistic capabilities of the CSSG architectures,we aim to address pressing environmental and energy challenges and drive scientific progress in these fields.
基金financially supported by the Development Fund of Shandong Provincial Key Laboratory of Deep Oil and Gas,the Fundamental Research Funds for the Central Universities(20CX02110A)the National Natural Science Foundation of China(41702142)
文摘Overpressure is a key factor for oil and gas charging in tight reservoirs,but it is still a challenge to evaluate the overpressure evolution and its control on oil and gas charging.Taking Xujiahe Formation in the northeastern Sichuan Basin as an example,this paper presented a method for evaluating overpressure and its effect on natural gas charging in tight sandstone in compressional basin.The abnormally high pressure and its causes were analyzed by measured data and logging evaluation.Theoretical calculation and PVT simulation were used to investigate the amounts of overpressure resulted from hydrocarbon generation and tecto nic compression,respectively.Then the source rock-reservoir pressu re differences were calculated and the characteristics of natural gas charging during the natural gas charging periods were analyzed.It was revealed that hydrocarbon generation and tectonic compression were the main causes of the overpressure.The overpressure of both source rocks and reservoir exhibited a gradually increasing trend from Middle Jurassic to Early Cretaceous(J2-K1),then decreased since Later Cretaceous(K2),and some of that preserved to now.The contributions of the hydrocarbon generation and tectonic compression to overpressure were different in different periods.The residual pressure difference between the source rocks and the reservoir is the major driving force for tight sandstone gas charging.The main hydrocarbon generating area of the source rocks and the area of high driving force were major natural gas enrichment areas,and the driving force determined the natural gas charging space in the pore throat system of the reservoir.This research helps evaluate the overpressure and pressure difference between source rocks and reservoir in compressed basin,as well as investigate the effective pore throat space of tight gas charging by the driver of overpressure.
基金Supported by the National Natural Science Foundation of China(41502132)the China National Science and Technology Major Project(2017ZX05001-004)
文摘The origin of overpressure and its effect on petroleum accumulation in the large Permian/Triassic conglomerate oil province in the Mahu Sag,Junggar Basin have been investigated based on comprehensive analysis of log curve combinations,loading-unloading curves,sonic velocity-density cross-plot,and porosity comparison data.The study results show that there are two kinds of normal compaction models in the study area,namely,two-stage linear model and exponent model;overpressure in the large conglomerate reservoirs including Lower Triassic Baikouquan Formation and Permian Upper and Lower Wu’erhe Formations is the result of pressure transfer,and the source of overpressure is the overpressure caused by hydrocarbon generation of Permian Fengcheng Formation major source rock.The petroleum migrated through faults under the driving of hydrocarbon generation overpressure into the reservoirs to accumulate,forming the Permian and Triassic overpressure oil and gas reservoirs.The occurrence and distribution of overpressure are controlled by the source rock maturity and strike-slip faults connecting the source rock and conglomerate reservoirs formed from Indosinian Movement to Himalayan Movement.As overpressure is the driving force for petroleum migration in the large Mahu oil province,the formation and distribution of petroleum reservoirs above the source rock in this area may have a close relationship with the occurrence of overpressure.
基金supported by the National Basic Research Program of China (2007CB407207)National Natural Science Foundation of China (30800888)
文摘As more and more farmland is converted to forestry, the need for effective decision support regarding the use of land in the fragile ecological environment of the Loess Plateau hilly-gully area. The Luoyugou watershed was chosen as the study area to calculate the single dynamic degree, integrated dynamic degree, and change indexes of land use, as well as the land-use type transition matrix. This was done by interpreting the TM and SPOT images of the Luoyugou watershed in 1986, 1995, and2004 and making statistical analysis. The results of ou statistical analysis show that the conversion of slope farm land to terrace and forest land plays a dominant role in land-use changes in the Luoyugou watershed from 1986 to2004. The land-use changes are mainly driven by popula tion growth, socio-economic development, consume spending, and investment in forest ecology.
基金financial support by the National Natural Science Foundation of China(Grant No.91534120)China National Petroleum Company under the contract number DQZX-KY-17-019
文摘A bidisperse model for transient diffusion and adsorption processes in porous materials is presented in this paper.The mathematical model is solved by numerical methods based on finite elements combined with the linear driving force approximation.A criterion based on the model to identify the diffusion controlling mechanism(macropore diffusion,micropore diffusion,or both)is proposed.The effects of different adsorption isotherms(linear,Freundlich,or Langmuir)on the concentration profiles and on curves of fractional uptake versus time are investigated.In addition,the influences of model parameters concerning the pore networks on the fractional uptake are studied as well.
基金the National Key R&D Program of China (2017YFA0204701)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB12010200)+1 种基金National Basic Research Program of China (Program 973) (No. 2014CB643502)the National Natural Science Foundation of China (21572234, 21661132006, 91833304, 21402194) for their financial support。
文摘Three small bandgap non-fullerene(SBG NFAs) acceptors,BDTI,BDTI-2 F and BDTI-4 F,based on a carbon-oxygen bridged central core and thieno[3,4-b]thiophene linker,end-capped with varied electronwithdrawing terminal groups,were designed and synthesized.The acceptors exhibit strong absorption from 600 nm to 1000 nm.The optimal device incorporating designed NFA and PTB7-Th polymer donor achieves a power conversion efficiency of 9.11% with near 0 eV HOMO offset.The work presents a case study of efficient non-fullerene solar cells with small HOMO offsets,which is achieved by blending PTB7-Th with fine-tuned SBG acceptor.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11422221,11672289,71371175,and 71431003)
文摘In this paper, the evacuation dynamics in an artificial room with only one exit is investigated via experiments and modeling. Two sets of experiments are implemented, in which pedestrians are asked to escape individually. It is found that the average evacuation time gap is essentially constant. To model the evacuation dynamics, an improved social force model is proposed, in which it is assumed that the driving force of a pedestrian cannot be performed when the resultant physical force exceeds a threshold. Simulation results are in good agreement with the experimental ones.
