China sedimentary basins present abundant natural gas resource thanks to its unique geological settings.Marine highly-matured hydrocarbon source rocks,widespread coal-measure strata and low temperature Quaternary sali...China sedimentary basins present abundant natural gas resource thanks to its unique geological settings.Marine highly-matured hydrocarbon source rocks,widespread coal-measure strata and low temperature Quaternary saline strata,etc.,indicate the wide foreground of China natural gas resources. Up to now,most of the petroliferous basins have been discovered to have wholesale natural gas accumulation from Precambrian,Paleozoic,Mesozoic to Cenozoic in the east,the central,the west and the coast of China.These large and medium-scale gas reservoirs are mainly composed of hydrocarbon gas with big dry coefficient,tiny non-hydrocarbon,wide carbon isotope distribution and varying origin types,the hydrocarbon gas includes coal-formed gas,oil-formed gas,biogenic gas and inorganic gas, etc.Coal-formed gas is the main type of China natural gas resources,in particular several explored large-scale gas fields(>100 billion cubic meter)of Kela 2,Sulige and Daniudi,etc.,they all belong to coal-formed gas fields or the gas fields consisting mostly of coal-formed gas.Oil-formed gas is also abundant in China marine basins,for example marine natural gas of Sichuan Basin generated from crude oil cracking gas.Primary and secondary biogenic gas fields were discovered respectively in the Qaidam Basin and Western Slope of Songliao Basin.In addition,inorganic gases are mainly distributed in the eastern China,in particular the Songliao Basin with abundant carbon dioxide accumulation,indicating that the eastern China present large exploration potential of inorganic gas.展开更多
This study presents an autoencoder-embedded optimization(AEO)algorithm which involves a bi-population cooperative strategy for medium-scale expensive problems(MEPs).A huge search space can be compressed to an informat...This study presents an autoencoder-embedded optimization(AEO)algorithm which involves a bi-population cooperative strategy for medium-scale expensive problems(MEPs).A huge search space can be compressed to an informative lowdimensional space by using an autoencoder as a dimension reduction tool.The search operation conducted in this low space facilitates the population with fast convergence towards the optima.To strike the balance between exploration and exploitation during optimization,two phases of a tailored teaching-learning-based optimization(TTLBO)are adopted to coevolve solutions in a distributed fashion,wherein one is assisted by an autoencoder and the other undergoes a regular evolutionary process.Also,a dynamic size adjustment scheme according to problem dimension and evolutionary progress is proposed to promote information exchange between these two phases and accelerate evolutionary convergence speed.The proposed algorithm is validated by testing benchmark functions with dimensions varying from 50 to 200.As indicated in our experiments,TTLBO is suitable for dealing with medium-scale problems and thus incorporated into the AEO framework as a base optimizer.Compared with the state-of-the-art algorithms for MEPs,AEO shows extraordinarily high efficiency for these challenging problems,t hus opening new directions for various evolutionary algorithms under AEO to tackle MEPs and greatly advancing the field of medium-scale computationally expensive optimization.展开更多
This paper investigates the socio-cultural challenges of the small-scale batik and tie-dye production and retailing industry in Ghana. The research is based on a qualitative research approach that employs interviews a...This paper investigates the socio-cultural challenges of the small-scale batik and tie-dye production and retailing industry in Ghana. The research is based on a qualitative research approach that employs interviews and observation for data collection. In all, sixteen (16) participants were sampled through purposive techniques. Data collected were transcribed, classified and analysed through thematic and descriptive analysis. The study found that family roles contradict the business role, pressure from family members, poor support from society members, some religious teachings, age, ethnicity and lifestyle of certain people among others. The study concludes that socio-cultural challenges have led to the collapse of most batik and tie-dye production and retailing sectors leaving thousands of Ghanaians jobless. It recommends among others that producers and retailers of batik and tie-dye must separate family roles from work responsibilities to enable them to perform effectively. Again, family members, parents and peers must desist from putting pressure on the entrepreneurs for freebies and the government must resource NBSSI, GEPA and GSB to have regular in-service training to batik and tie-dye producers and retailers to address poor financial management and technical challenges and also on product quality on the international market.展开更多
Offshore structures are generally classified as small-scale structures or large-scale structures.Their wave forces are then estimated by Morison equation and diffraction/radiation theories,respectively.However,the cla...Offshore structures are generally classified as small-scale structures or large-scale structures.Their wave forces are then estimated by Morison equation and diffraction/radiation theories,respectively.However,the classification criterion is not well quantified.In the present paper,a numerical wave flume is established to simulate the wave forces acting on a fixed and vertical surface-piercing circular cylinder under linear waves.By solving Navier–Stokes equation and Euler equation with free surface involved,respectively,the viscous force and inertia force are separated accurately.The variation of viscous force and inertia force with the cylinder diameter to wave length ratio is discussed in detail.The scale intervals for significant viscous and diffraction effects are given.The error caused by neglecting viscous and diffraction forces is quantitatively analyzed.Based on these analysis,the concept of medium-scale structure is proposed and the classification criteria for small-,medium-and large-scale structures are given.In the meantime,the estimation methods of wave forces for different scales of structures are suggested.展开更多
OI 630.0 nm airglow observations,from a new observatory at Bom Jesus de Lapa,were used to study the interaction between EPBs(Equatorial Plasma Bubbles)and the MSTID(Medium-Scale Traveling Ionospheric Disturbance)over ...OI 630.0 nm airglow observations,from a new observatory at Bom Jesus de Lapa,were used to study the interaction between EPBs(Equatorial Plasma Bubbles)and the MSTID(Medium-Scale Traveling Ionospheric Disturbance)over the Northeast region in Brazil.On the night of September 16 to 17,2020,an EPB was observed propagating eastward,in an apparent fossil stage,until it interacted with a dark band electrified MSTID(e MSTID).After the interaction,four EPBs merged,followed by an abrupt southward development and bifurcations.Analysis of the data suggests that an eastward polarization electric field,induced by the dark band e MSTID,forced the EPB into an upward drift,growing latitudinally along the magnetic field lines and then bifurcating.展开更多
分布式冷热电联供(combined cooling,heating and power,CCHP)系统是一种小型、临近用户的新型供能方式,可避免能量长距离传输过程损失,同时具有灵活、高效、环保特点,成为大规模、集中式供能方式的重要补充。中小型发电装置是分布式冷...分布式冷热电联供(combined cooling,heating and power,CCHP)系统是一种小型、临近用户的新型供能方式,可避免能量长距离传输过程损失,同时具有灵活、高效、环保特点,成为大规模、集中式供能方式的重要补充。中小型发电装置是分布式冷热电联供系统的核心,制冷和制热也都围绕发电装置余热展开。对适合分布式冷热电联供系统的2类中小型发电装置的基本工作原理、热力性能和相关研究进展进行综述。一类是以化石燃料为能源输入的中小型发电装置,包括微型燃气轮机、燃气内燃机、小型燃气轮机和燃料电池;另一类是以发电装置余热或太阳能集热等其他热源为能源输入的中小型发电装置,包括有机朗肯循环、正逆耦合循环、热声发电机等。最后,对2类中小型发电装置的优缺点进行对比分析,为分布式供能系统的发电装置选型、系统方案设计等提供参考。展开更多
文摘China sedimentary basins present abundant natural gas resource thanks to its unique geological settings.Marine highly-matured hydrocarbon source rocks,widespread coal-measure strata and low temperature Quaternary saline strata,etc.,indicate the wide foreground of China natural gas resources. Up to now,most of the petroliferous basins have been discovered to have wholesale natural gas accumulation from Precambrian,Paleozoic,Mesozoic to Cenozoic in the east,the central,the west and the coast of China.These large and medium-scale gas reservoirs are mainly composed of hydrocarbon gas with big dry coefficient,tiny non-hydrocarbon,wide carbon isotope distribution and varying origin types,the hydrocarbon gas includes coal-formed gas,oil-formed gas,biogenic gas and inorganic gas, etc.Coal-formed gas is the main type of China natural gas resources,in particular several explored large-scale gas fields(>100 billion cubic meter)of Kela 2,Sulige and Daniudi,etc.,they all belong to coal-formed gas fields or the gas fields consisting mostly of coal-formed gas.Oil-formed gas is also abundant in China marine basins,for example marine natural gas of Sichuan Basin generated from crude oil cracking gas.Primary and secondary biogenic gas fields were discovered respectively in the Qaidam Basin and Western Slope of Songliao Basin.In addition,inorganic gases are mainly distributed in the eastern China,in particular the Songliao Basin with abundant carbon dioxide accumulation,indicating that the eastern China present large exploration potential of inorganic gas.
基金supported in part by the National Natural Science Foundation of China(72171172,62088101)in part by the Shanghai Science and Technology Major Special Project of Shanghai Development and Reform Commission(2021SHZDZX0100)+2 种基金in part by the Shanghai Commission of Science and Technology(19511132100,19511132101)in part by the China Scholarship Councilin part by the Deanship of Scientific Research(DSR)at King Abdulaziz University(KAU),Jeddah,Saudi Arabia(FP-146-43)。
文摘This study presents an autoencoder-embedded optimization(AEO)algorithm which involves a bi-population cooperative strategy for medium-scale expensive problems(MEPs).A huge search space can be compressed to an informative lowdimensional space by using an autoencoder as a dimension reduction tool.The search operation conducted in this low space facilitates the population with fast convergence towards the optima.To strike the balance between exploration and exploitation during optimization,two phases of a tailored teaching-learning-based optimization(TTLBO)are adopted to coevolve solutions in a distributed fashion,wherein one is assisted by an autoencoder and the other undergoes a regular evolutionary process.Also,a dynamic size adjustment scheme according to problem dimension and evolutionary progress is proposed to promote information exchange between these two phases and accelerate evolutionary convergence speed.The proposed algorithm is validated by testing benchmark functions with dimensions varying from 50 to 200.As indicated in our experiments,TTLBO is suitable for dealing with medium-scale problems and thus incorporated into the AEO framework as a base optimizer.Compared with the state-of-the-art algorithms for MEPs,AEO shows extraordinarily high efficiency for these challenging problems,t hus opening new directions for various evolutionary algorithms under AEO to tackle MEPs and greatly advancing the field of medium-scale computationally expensive optimization.
文摘This paper investigates the socio-cultural challenges of the small-scale batik and tie-dye production and retailing industry in Ghana. The research is based on a qualitative research approach that employs interviews and observation for data collection. In all, sixteen (16) participants were sampled through purposive techniques. Data collected were transcribed, classified and analysed through thematic and descriptive analysis. The study found that family roles contradict the business role, pressure from family members, poor support from society members, some religious teachings, age, ethnicity and lifestyle of certain people among others. The study concludes that socio-cultural challenges have led to the collapse of most batik and tie-dye production and retailing sectors leaving thousands of Ghanaians jobless. It recommends among others that producers and retailers of batik and tie-dye must separate family roles from work responsibilities to enable them to perform effectively. Again, family members, parents and peers must desist from putting pressure on the entrepreneurs for freebies and the government must resource NBSSI, GEPA and GSB to have regular in-service training to batik and tie-dye producers and retailers to address poor financial management and technical challenges and also on product quality on the international market.
基金This work was supported by the National Key R&D Program of China(Grant 2017yfc1404200)the National Natural Science Foundation of China(Grant 11572332)and the Strategic Priority Research Program of the Chinese Academy of Sciences(Grants xdb22040203 and xda22OOOOOO).
文摘Offshore structures are generally classified as small-scale structures or large-scale structures.Their wave forces are then estimated by Morison equation and diffraction/radiation theories,respectively.However,the classification criterion is not well quantified.In the present paper,a numerical wave flume is established to simulate the wave forces acting on a fixed and vertical surface-piercing circular cylinder under linear waves.By solving Navier–Stokes equation and Euler equation with free surface involved,respectively,the viscous force and inertia force are separated accurately.The variation of viscous force and inertia force with the cylinder diameter to wave length ratio is discussed in detail.The scale intervals for significant viscous and diffraction effects are given.The error caused by neglecting viscous and diffraction forces is quantitatively analyzed.Based on these analysis,the concept of medium-scale structure is proposed and the classification criteria for small-,medium-and large-scale structures are given.In the meantime,the estimation methods of wave forces for different scales of structures are suggested.
基金supported by Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)by Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),under the processes 470589/2012-4,305461/2015-0,303511/2017-6,307653/2017-0,and 169815/2017-0the Fundacao de AmparoàPesquisa do Estado de Sao Paulo(FAPESP)under the process 2018/09066-8。
文摘OI 630.0 nm airglow observations,from a new observatory at Bom Jesus de Lapa,were used to study the interaction between EPBs(Equatorial Plasma Bubbles)and the MSTID(Medium-Scale Traveling Ionospheric Disturbance)over the Northeast region in Brazil.On the night of September 16 to 17,2020,an EPB was observed propagating eastward,in an apparent fossil stage,until it interacted with a dark band electrified MSTID(e MSTID).After the interaction,four EPBs merged,followed by an abrupt southward development and bifurcations.Analysis of the data suggests that an eastward polarization electric field,induced by the dark band e MSTID,forced the EPB into an upward drift,growing latitudinally along the magnetic field lines and then bifurcating.
文摘分布式冷热电联供(combined cooling,heating and power,CCHP)系统是一种小型、临近用户的新型供能方式,可避免能量长距离传输过程损失,同时具有灵活、高效、环保特点,成为大规模、集中式供能方式的重要补充。中小型发电装置是分布式冷热电联供系统的核心,制冷和制热也都围绕发电装置余热展开。对适合分布式冷热电联供系统的2类中小型发电装置的基本工作原理、热力性能和相关研究进展进行综述。一类是以化石燃料为能源输入的中小型发电装置,包括微型燃气轮机、燃气内燃机、小型燃气轮机和燃料电池;另一类是以发电装置余热或太阳能集热等其他热源为能源输入的中小型发电装置,包括有机朗肯循环、正逆耦合循环、热声发电机等。最后,对2类中小型发电装置的优缺点进行对比分析,为分布式供能系统的发电装置选型、系统方案设计等提供参考。
