Promoting the deep integration of advanced manufacturing and producer services is not only a key path for metropolitan to climb the global value chain,but also an important new driving force for optimizing urban spati...Promoting the deep integration of advanced manufacturing and producer services is not only a key path for metropolitan to climb the global value chain,but also an important new driving force for optimizing urban spatial structure.Based on the two dimen-sions of industrial linkage and spatial co-agglomeration from the perspective of industrial integration,taking Beijing,China as a case,using industrial input-output data,micro-enterprise spatial data,and methods such as industrial linkage model,standard deviation el-lipse,and spatial similarity coefficient,this study explores the coupling relationship between industrial linkage and spatial co-agglomer-ation of advanced manufacturing and producer services from 2007 to 2020.The results demonstrate that:1)the industrial linkage between advanced manufacturing and producer services in Beijing has an upward trend,in which the business services have the most significant improvement,in which the business services have the most improvement while the technology services have the most de-crease,but in general,the industrial linkage between the two industries shows a low level.2)Producer services were more spatially clustered than advanced manufacturing,and the degree of spatial co-agglomeration of the two also showed an increasing trend,with strong regional and industrial heterogeneity characteristics,among which the pairing industry involving commerce services and techno-logy services had a more obvious improvement.3)The coupling analysis found that the spatial dependence between advanced manufac-turing and producer services decreased,showing a weak positive correlation and a decreasing trend between industrial linkage and spa-tial co-agglomeration;the heterogeneity among subdivision pairs is prominent,and the strong correlation between industries does not mean that there is an inevitable spatial co-agglomeration.4)Based on the differences in coupling relationships and influence mechan-isms,four coupling modes are identified:H-H type,H-L type,L-L type,and L-H type.Finally,this study proposes three policy implica-tions for the integration of advanced manufacturing and producer services in metropolitan areas.展开更多
Produced water reinjection is a common strategy in offshore oilfield operations,yet the presence of solid particles in produced water can lead to localized formation pressure buildup,increasing the risk of rock fractu...Produced water reinjection is a common strategy in offshore oilfield operations,yet the presence of solid particles in produced water can lead to localized formation pressure buildup,increasing the risk of rock fracturing and leakage.In this study,we present an integrated experimental and numerical investigation to quantify the effects of particle migration on formation pressure and the spatial diffusion of injected water.Dynamic plugging experiments were performed to systematically examine the influence of injection rate and injection volume on core permeability.Results demonstrate that higher injection rates substantially reduce permeability,and the derived relationship between permeability and injection volume enables dynamic assessment of permeability evolution during reinjection.Complementary numerical simulations explored the impacts of injection length,particle concentration,and injection rate on formation pressure and diffusion behavior.Findings indicate that extending the injection section promotes pressure distribution and enlarges the diffusion area,whereas elevated particle concentrations and injection rates accelerate formation plugging,causing rapid pressure rise and constrained diffusion.展开更多
We report the observation of Zeeman splitting in multiple spectral lines emitted by a laser-produced,magnetized plasma(1–3×10^(18)cm^(-3),1–15 eV)in the context of a laboratory astrophysics experiment under a c...We report the observation of Zeeman splitting in multiple spectral lines emitted by a laser-produced,magnetized plasma(1–3×10^(18)cm^(-3),1–15 eV)in the context of a laboratory astrophysics experiment under a controlled magneticfield up to 20T.Nitrogen lines(NII)in the visible range were used to diagnose the magneticfield and plasma conditions.This was performed by coupling our data with(563–574 nm)the Stark–Zeeman line-shape code PPPB.The excellent agreement between experiment and simulations paves the way for a non-intrusive experimental platform to get time-resolved measurements of the local magneticfield in laboratory plasmas.展开更多
The research conducted investigation and survey on 186 farm households in 2014 and carried out economic evaluation on ＂planting three to produce four＂ highyielding project of super hybrid rice. The results showed th...The research conducted investigation and survey on 186 farm households in 2014 and carried out economic evaluation on ＂planting three to produce four＂ highyielding project of super hybrid rice. The results showed that the project of ＂planting three to produce four＂ performed significantly in terms of increasing yields and incomes. For example, per unit area yield of one-season late hybrid rice and middleseason hybrid rice proved the highest, and net income from middle-season rice in Longhui was the highest. It is obvious that to increase per unit yield is key for improving net incomes and to reduce machine fees and worker fees is crucial for decreasing fees.展开更多
Green Barrier,a significant component of the non-tariff barrier,is playing a more and more important role in the international trade.The impact of the green barrier by EU on Chinese farm products has become a crucial ...Green Barrier,a significant component of the non-tariff barrier,is playing a more and more important role in the international trade.The impact of the green barrier by EU on Chinese farm products has become a crucial problem which is attracting more and more attention of Chinese people.This paper begins with the appearance of the green barrier,emphatically studies the impact of green barrier of EU on the export of farm produces of China and put forward the countermeasures in end.展开更多
Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis （ME）, focusing on changes in chemical oxygen demand （COD） and biodegradability. Results showed that ...Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis （ME）, focusing on changes in chemical oxygen demand （COD） and biodegradability. Results showed that COD exhibited an abnormal change in the single anaerobic system in which it increased within the first 168 hr, but then decreased to 222 mg/L after 360 hr. The biological oxygen demand （five-day） （BOD5）/COD ratio of the water increased from 0.05 to 0.15. Hydrocarbons in the wastewater, such as pectin, degraded to small molecules during the hydrolytic acidification process. Comparatively, the effect of ME was also investigated. The COD underwent a slight decrease and the BOD5/COD ratio of the water improved from 0,05 to 0.17 after ME. Removal of COD was 38.3% under the idealized ME conditions （pH 6.0）, using iron and active carbon （80 and 40 g/L, respectively）. Coupling the anaerobic process with ME accelerated the COD removal ratio （average removal was 53.3%）. Gas chromatography/mass spectrometry was used to analyze organic species conversion. This integrated system appeared to be a useful option for the treatment of water produced in oilfields.展开更多
Globalization and informatization have accelerated city networking process over the world, which makes research on city network a hot topic in the fields of urban geography and economic geography. With Chinese economi...Globalization and informatization have accelerated city networking process over the world, which makes research on city network a hot topic in the fields of urban geography and economic geography. With Chinese economic structure adjustment and city economic growth, producer services have begun to play an increasingly important role in city-region networking. This paper employs the methodology of world city network to analyze and explain the spatial development characteristics of China's urban network system based on the data of nationwide producer services enterprise network. The research result indicated that the distribution of producer services network has a positive effect on the development of Chinese city networks. City network connectivity is closely related to the significance of city in producer services development, and the former will gradually decline with the drop of the latter. Accordingly, the 64 cities can be divided into the national central cities, regional central cities, sub-regional central cities and local central cities in accordance with their position and role in the nationwide producer services network. It is concluded that high-grade cities with quality producer services dominate the pattern of Chinese city networks and there emerges three spatial agglomerations of producer services enterprises in Changjiang (Yangtze) River Delta, Zhujiang (Pearl) River Delta and Beijing-Tianjin-Tangshan Economical Region. Moreover, the distribution of different producer services industry varies from city to city, which also affects the characteristics of network development.展开更多
As the Central Place Theory indicates, the centricity of a central city can influence the extension of its ser- vice. Since the service industry in the theory is mostly consumer services, it is worth studying the rela...As the Central Place Theory indicates, the centricity of a central city can influence the extension of its ser- vice. Since the service industry in the theory is mostly consumer services, it is worth studying the relationship between the producer services and the centricity of the city in the service society with producer services becoming a more im- portant part of the service industry. The paper takes the case of the Zhujiang (Pearl) River Delta (PRD), a developed region in China, to study the relationship between the developing level of producer services and the urban hierarchy. Based on the analysis about the spatial difference of the producer services in the nine cities of the PRD, and the divi- sion of the nine cities according to some economic indices, it is shown that there is a correlation between the develop- ing level of producer services and the urban hierarchy. Furthermore, two deductions about the future status of the pro- ducer services in the city and the location of the producer services in a large region can be made from this correlation between the developing level of producer services and the urban hierarchy.展开更多
The emulsion stability of oilfield produced water is related to the oil-water interfacial film strength and the zeta potential of the oil droplets. We investigated the effects of water treatment agents （corrosion inh...The emulsion stability of oilfield produced water is related to the oil-water interfacial film strength and the zeta potential of the oil droplets. We investigated the effects of water treatment agents （corrosion inhibitor SL-2, scale inhibitor HEDP, germicide 1227, and flocculant polyaluminium chloride PAC） on the stability of oilfield produced water. The influence of these treatment agents on oil-water interfacial properties and the mechanism of these agents acting on the oilfield produced water were studied by measuring the interfacial shear viscosity, interfacial tension and zeta electric potential. The results indicated that the scale inhibitor HEDP could increase the oil-water interfacial film strength, and it could also increase the absolute value of the zeta potential of oil droplets. HEDP played an important role in the stability of the emulsion. Polyaluminum chloride （PAC） reduced the stability of the emulsion by considerably decreasing the absolute value of the zeta potential of oil droplets. Corrosion inhibitor SL-2 and germicide 1227 could decrease the oil-water interfacial tension, whereas they had little influence on oil-water interfacial shear viscosity and oil-water interfacial electricity properties.展开更多
Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only ...Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux. As for the result that turbulence promoter increase fluid velocity, wall shear rates and produce secondary flows or instabilities, the influence of turbulence promoter was investigated on permeate flux during produced water ultrafiltration and the potential application of this arrangement for an industrial development. Experimental investigations were performed on 100 KDa molecular weight cut-off PVDF single-channel tubular membrane module using four kinds of turbulence promoters. It is observed that the significant flux enhancement in the range of 83%--164% was achieved while the hydraulic dissipated power per unit volume of permeate decreased from 31%--42%, which indicated that the using of turbulence promoter is more efficient than operation without the turbulence promoter. The effects of transmembrane pressure and cross-flow velocity with and without turbulence promoter were studied as well. Among the four kinds of turbulence promoters, winding inserts with 20.0 mm pitch and 1.0 mm wire diameter showed better performances than the others did.展开更多
To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,tota...To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,total dissolved solids （TDS）,total hardness,and concentrations of metasilicic acid,sodium and kalium,calcium ion,magnesium ion,ammonium iron,bicarbonate ion,carbonate,chloride,sulfate ion,nitrate ion,fluoride,lithium,zinc,nickel,manganese,iron,boron,barium,etc.of the samples were measured.Research results showed the following：（1） Concentrations of TDS,chloride,fluoride,sodium and kalium,ammonium,iron,and barium in the water coproduced with coalbed gas exceeded the national standards of China; however,physical,chemical,and biological properties of shallow groundwater could meet the national standard.（2） The water produced from coalbed contained mainly Na-Cl·HCO3,with average TDS of 4588.5 ppm,whereas shallow groundwater contained a mixture of chemicals including Na.Mg.Ca-HCO3·SO4 and Na.Mg-HCO3·SO4,with average TDS of 663.8 ppm.（3） In general,it was observed that bicarbonate and sodium accumulated in a reducing environment and deeper system,while depletion of hydrogen ions and dissolution of sulfate,calcium,and magnesium occurred in a redox environment and shallow system.（4） Sodium and kalium,ammonium,chloride,and bicarbonate ions were the main ions found in the study area.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.42371181)。
文摘Promoting the deep integration of advanced manufacturing and producer services is not only a key path for metropolitan to climb the global value chain,but also an important new driving force for optimizing urban spatial structure.Based on the two dimen-sions of industrial linkage and spatial co-agglomeration from the perspective of industrial integration,taking Beijing,China as a case,using industrial input-output data,micro-enterprise spatial data,and methods such as industrial linkage model,standard deviation el-lipse,and spatial similarity coefficient,this study explores the coupling relationship between industrial linkage and spatial co-agglomer-ation of advanced manufacturing and producer services from 2007 to 2020.The results demonstrate that:1)the industrial linkage between advanced manufacturing and producer services in Beijing has an upward trend,in which the business services have the most significant improvement,in which the business services have the most improvement while the technology services have the most de-crease,but in general,the industrial linkage between the two industries shows a low level.2)Producer services were more spatially clustered than advanced manufacturing,and the degree of spatial co-agglomeration of the two also showed an increasing trend,with strong regional and industrial heterogeneity characteristics,among which the pairing industry involving commerce services and techno-logy services had a more obvious improvement.3)The coupling analysis found that the spatial dependence between advanced manufac-turing and producer services decreased,showing a weak positive correlation and a decreasing trend between industrial linkage and spa-tial co-agglomeration;the heterogeneity among subdivision pairs is prominent,and the strong correlation between industries does not mean that there is an inevitable spatial co-agglomeration.4)Based on the differences in coupling relationships and influence mechan-isms,four coupling modes are identified:H-H type,H-L type,L-L type,and L-H type.Finally,this study proposes three policy implica-tions for the integration of advanced manufacturing and producer services in metropolitan areas.
基金supported by the National Natural Science Foundation of China(No.52204026).
文摘Produced water reinjection is a common strategy in offshore oilfield operations,yet the presence of solid particles in produced water can lead to localized formation pressure buildup,increasing the risk of rock fracturing and leakage.In this study,we present an integrated experimental and numerical investigation to quantify the effects of particle migration on formation pressure and the spatial diffusion of injected water.Dynamic plugging experiments were performed to systematically examine the influence of injection rate and injection volume on core permeability.Results demonstrate that higher injection rates substantially reduce permeability,and the derived relationship between permeability and injection volume enables dynamic assessment of permeability evolution during reinjection.Complementary numerical simulations explored the impacts of injection length,particle concentration,and injection rate on formation pressure and diffusion behavior.Findings indicate that extending the injection section promotes pressure distribution and enlarges the diffusion area,whereas elevated particle concentrations and injection rates accelerate formation plugging,causing rapid pressure rise and constrained diffusion.
基金supported by grants managed by l’Agence Nationale de la Recherche under the Investissements d’Avenir programs Grant Nos. ANR-18-EURE-0014, ANR-10-LABX-0039-PALM, and ANR-22-CE30-0044supported by grants from Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant No. 23K20038)+2 种基金JSPS Core-to-Core program (Grant No. JPJSCCA20230003)carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200-EUROfusion)operated within the framework of the Enabling Research Project No. AWP24-ENR-IFE.02.CEA-01 “Magnetized ICF”
文摘We report the observation of Zeeman splitting in multiple spectral lines emitted by a laser-produced,magnetized plasma(1–3×10^(18)cm^(-3),1–15 eV)in the context of a laboratory astrophysics experiment under a controlled magneticfield up to 20T.Nitrogen lines(NII)in the visible range were used to diagnose the magneticfield and plasma conditions.This was performed by coupling our data with(563–574 nm)the Stark–Zeeman line-shape code PPPB.The excellent agreement between experiment and simulations paves the way for a non-intrusive experimental platform to get time-resolved measurements of the local magneticfield in laboratory plasmas.
文摘The research conducted investigation and survey on 186 farm households in 2014 and carried out economic evaluation on ＂planting three to produce four＂ highyielding project of super hybrid rice. The results showed that the project of ＂planting three to produce four＂ performed significantly in terms of increasing yields and incomes. For example, per unit area yield of one-season late hybrid rice and middleseason hybrid rice proved the highest, and net income from middle-season rice in Longhui was the highest. It is obvious that to increase per unit yield is key for improving net incomes and to reduce machine fees and worker fees is crucial for decreasing fees.
文摘Green Barrier,a significant component of the non-tariff barrier,is playing a more and more important role in the international trade.The impact of the green barrier by EU on Chinese farm products has become a crucial problem which is attracting more and more attention of Chinese people.This paper begins with the appearance of the green barrier,emphatically studies the impact of green barrier of EU on the export of farm produces of China and put forward the countermeasures in end.
基金supported by the Water Pollution Control and Management Project,China(No. 2009ZX07208)the Ministry of Science and Technology,China,for partially funding this study
文摘Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis （ME）, focusing on changes in chemical oxygen demand （COD） and biodegradability. Results showed that COD exhibited an abnormal change in the single anaerobic system in which it increased within the first 168 hr, but then decreased to 222 mg/L after 360 hr. The biological oxygen demand （five-day） （BOD5）/COD ratio of the water increased from 0.05 to 0.15. Hydrocarbons in the wastewater, such as pectin, degraded to small molecules during the hydrolytic acidification process. Comparatively, the effect of ME was also investigated. The COD underwent a slight decrease and the BOD5/COD ratio of the water improved from 0,05 to 0.17 after ME. Removal of COD was 38.3% under the idealized ME conditions （pH 6.0）, using iron and active carbon （80 and 40 g/L, respectively）. Coupling the anaerobic process with ME accelerated the COD removal ratio （average removal was 53.3%）. Gas chromatography/mass spectrometry was used to analyze organic species conversion. This integrated system appeared to be a useful option for the treatment of water produced in oilfields.
基金Under the auspices of National Natural Science Foundation of China(No.40971094)
文摘Globalization and informatization have accelerated city networking process over the world, which makes research on city network a hot topic in the fields of urban geography and economic geography. With Chinese economic structure adjustment and city economic growth, producer services have begun to play an increasingly important role in city-region networking. This paper employs the methodology of world city network to analyze and explain the spatial development characteristics of China's urban network system based on the data of nationwide producer services enterprise network. The research result indicated that the distribution of producer services network has a positive effect on the development of Chinese city networks. City network connectivity is closely related to the significance of city in producer services development, and the former will gradually decline with the drop of the latter. Accordingly, the 64 cities can be divided into the national central cities, regional central cities, sub-regional central cities and local central cities in accordance with their position and role in the nationwide producer services network. It is concluded that high-grade cities with quality producer services dominate the pattern of Chinese city networks and there emerges three spatial agglomerations of producer services enterprises in Changjiang (Yangtze) River Delta, Zhujiang (Pearl) River Delta and Beijing-Tianjin-Tangshan Economical Region. Moreover, the distribution of different producer services industry varies from city to city, which also affects the characteristics of network development.
基金Foundation item: Under the auspices of National Natural Science Foundation of China (No. 40125003, No. 40601029)Natural Science Foundation of Guangdong Province (No. 06300790)
文摘As the Central Place Theory indicates, the centricity of a central city can influence the extension of its ser- vice. Since the service industry in the theory is mostly consumer services, it is worth studying the relationship between the producer services and the centricity of the city in the service society with producer services becoming a more im- portant part of the service industry. The paper takes the case of the Zhujiang (Pearl) River Delta (PRD), a developed region in China, to study the relationship between the developing level of producer services and the urban hierarchy. Based on the analysis about the spatial difference of the producer services in the nine cities of the PRD, and the divi- sion of the nine cities according to some economic indices, it is shown that there is a correlation between the develop- ing level of producer services and the urban hierarchy. Furthermore, two deductions about the future status of the pro- ducer services in the city and the location of the producer services in a large region can be made from this correlation between the developing level of producer services and the urban hierarchy.
文摘The emulsion stability of oilfield produced water is related to the oil-water interfacial film strength and the zeta potential of the oil droplets. We investigated the effects of water treatment agents （corrosion inhibitor SL-2, scale inhibitor HEDP, germicide 1227, and flocculant polyaluminium chloride PAC） on the stability of oilfield produced water. The influence of these treatment agents on oil-water interfacial properties and the mechanism of these agents acting on the oilfield produced water were studied by measuring the interfacial shear viscosity, interfacial tension and zeta electric potential. The results indicated that the scale inhibitor HEDP could increase the oil-water interfacial film strength, and it could also increase the absolute value of the zeta potential of oil droplets. HEDP played an important role in the stability of the emulsion. Polyaluminum chloride （PAC） reduced the stability of the emulsion by considerably decreasing the absolute value of the zeta potential of oil droplets. Corrosion inhibitor SL-2 and germicide 1227 could decrease the oil-water interfacial tension, whereas they had little influence on oil-water interfacial shear viscosity and oil-water interfacial electricity properties.
基金The National Basic Research Program (973) of China (No. 2004CB418505)
文摘Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux. As for the result that turbulence promoter increase fluid velocity, wall shear rates and produce secondary flows or instabilities, the influence of turbulence promoter was investigated on permeate flux during produced water ultrafiltration and the potential application of this arrangement for an industrial development. Experimental investigations were performed on 100 KDa molecular weight cut-off PVDF single-channel tubular membrane module using four kinds of turbulence promoters. It is observed that the significant flux enhancement in the range of 83%--164% was achieved while the hydraulic dissipated power per unit volume of permeate decreased from 31%--42%, which indicated that the using of turbulence promoter is more efficient than operation without the turbulence promoter. The effects of transmembrane pressure and cross-flow velocity with and without turbulence promoter were studied as well. Among the four kinds of turbulence promoters, winding inserts with 20.0 mm pitch and 1.0 mm wire diameter showed better performances than the others did.
基金funded by the National Science and Technology Major Project (2011ZX05060-005 2009ZX05039-003)
文摘To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,total dissolved solids （TDS）,total hardness,and concentrations of metasilicic acid,sodium and kalium,calcium ion,magnesium ion,ammonium iron,bicarbonate ion,carbonate,chloride,sulfate ion,nitrate ion,fluoride,lithium,zinc,nickel,manganese,iron,boron,barium,etc.of the samples were measured.Research results showed the following：（1） Concentrations of TDS,chloride,fluoride,sodium and kalium,ammonium,iron,and barium in the water coproduced with coalbed gas exceeded the national standards of China; however,physical,chemical,and biological properties of shallow groundwater could meet the national standard.（2） The water produced from coalbed contained mainly Na-Cl·HCO3,with average TDS of 4588.5 ppm,whereas shallow groundwater contained a mixture of chemicals including Na.Mg.Ca-HCO3·SO4 and Na.Mg-HCO3·SO4,with average TDS of 663.8 ppm.（3） In general,it was observed that bicarbonate and sodium accumulated in a reducing environment and deeper system,while depletion of hydrogen ions and dissolution of sulfate,calcium,and magnesium occurred in a redox environment and shallow system.（4） Sodium and kalium,ammonium,chloride,and bicarbonate ions were the main ions found in the study area.
