China apparel industry, which is deeply embedded in the global production network (GPN), faces two urgent issues, social upgrading and economic upgrading. The study of GPN places great emphasis on the two issues. Base...China apparel industry, which is deeply embedded in the global production network (GPN), faces two urgent issues, social upgrading and economic upgrading. The study of GPN places great emphasis on the two issues. Based on the survey of Ningbo apparel industry, four key components of decent work in China apparel industry are discussed. The role of buyers in promoting decent work in suppliers can't be neglected. There are significant correlations between business type and some indicators of decent work. Though the majority of the apparel firms are engaging in processing, more and more firms are involved in marketing and branding. The upgrading trajectory of China apparel industry leads to the economic and social performances.展开更多
Under global production network,export cannot represent a country's gains from trade,and territory-based gains from trade refer to the remainder of export after deducting the input of intermediate goods and re-exp...Under global production network,export cannot represent a country's gains from trade,and territory-based gains from trade refer to the remainder of export after deducting the input of intermediate goods and re-export after value-added return.Ownership-based gains from trade refer to the remainder of territory-based gains from trade after further deducting the trade in value added(TVA) realized through the inflow of foreign factors.By creating a multicountry input and output model,this paper calculates the territory-based gains from trade,ownership-based gains from trade,and territory-based gains from trade for foreign countries realized through China's export,as well as valueadded return and territory-based gains from trade for foreign countries realized through China's import.This paper has arrived at the following conclusions:behind China's status as the largest goods exporting country in the world,most of Chinese exports contribute to the gains of foreign countries;value addition for foreign countries realized through China's export and value-added return realized through China's import mostly come from Taiwan region,Japan and South Korea in East Asia;a considerable part of gains from trade for the United States realized through China-US trade is achieved through indirect trade.展开更多
The International Textile Manufacturers Federation (ITMF) released its latest STATE OF TRADE REPORT Q2/2010, indicating that the strong global recovery in yarn and fabric production since their recent lows in the firs...The International Textile Manufacturers Federation (ITMF) released its latest STATE OF TRADE REPORT Q2/2010, indicating that the strong global recovery in yarn and fabric production since their recent lows in the first quarter of 2009 continued also into the second quarter of 2010. Besides, all regions contribute to the continued recovery.展开更多
In June,the Oerlikon Group released its annual Textile Report"The Fiber Year" for the tenth time.As it declared,the Asian position in world textile and apparel industry further increased at the expense of Eu...In June,the Oerlikon Group released its annual Textile Report"The Fiber Year" for the tenth time.As it declared,the Asian position in world textile and apparel industry further increased at the expense of European and American activities.展开更多
Various land use and land cover(LULC)products have been produced over the past decade with the development of remote sensing technology.Despite the differences in LULC classification schemes,there is a lack of researc...Various land use and land cover(LULC)products have been produced over the past decade with the development of remote sensing technology.Despite the differences in LULC classification schemes,there is a lack of research on assessing the accuracy of their application to croplands in a unified framework.Thus,this study evaluated the spatial and area accuracies of cropland classification for four commonly used global LULC products(i.e.,MCD12Q1V6,GlobCover2009,FROM-GLC and GlobeLand30)based on the harmonised FAO criterion,and quantified the relationships between four factors(i.e.,slope,elevation,field size and crop system)and cropland classification agreement.The validation results indicated that MCD12Q1 and GlobeLand30 performed well in cropland classification regarding spatial consistency,with overall accuracies of 94.90 and 93.52%,respectively.The FROMGLC showed the worst performance,with an overall accuracy of 83.17%.Overlaying the cropland generated by the four global LULC products,we found the proportions of complete agreement and disagreement were 15.51 and 44.72% for the cropland classification,respectively.High consistency was mainly observed in the Northeast China Plain,the Huang-Huai-Hai Plain and the northern part of the Middle-lower Yangtze Plain,China.In contrast,low consistency was detected primarily on the eastern edge of the northern and semiarid region,the Yunnan-Guizhou Plateau and southern China.Field size was the most important factor for mapping cropland.For area accuracy,compared with China Statistical Yearbook data at the provincial scale,the accuracies of different products in descending order were:GlobeLand30,FROM-GLC,MCD12Q1,and GlobCover2009.The cropland classification schemes mainly caused large area deviations among the four products,and they also resulted in the different ranks of spatial accuracy and area accuracy among the four products.Our results can provide valuable suggestions for selecting cropland products at the national or provincial scale and help cropland mapping and reconstruction,which is essential for food security and crop management,so they can also contribute to achieving the Sustainable Development Goals issued by the United Nations.展开更多
In the context of economic globalization,while multinational enterprises from developed countries occupy a high-end position in the global value chain,enterprises from developing countries are often marginalized in th...In the context of economic globalization,while multinational enterprises from developed countries occupy a high-end position in the global value chain,enterprises from developing countries are often marginalized in the world market.In China,resource-based state-owned enterprises(SOEs)are tasked with the mission of safeguarding resource security,and their internationalization development ideas and strategic deployment are significantly and fundamentally different from those of other non-state-owned enterprises and large multinational corporations.This study provides ideas for the globalization policies of enterprises in developing countries.We consider J Group in western China as a case and discuss its productive investment and global production network development from 2010 to 2019.We found that J Group was‘Partly'globalized,and there are multiple core nodes with the characteristics of centralized and decentralized coexistence in the production network;in addition,the overall layout centre shifted to Southeast Asia and China;however,its global production was restricted by the enterprise's investment security considerations,support and restrictions of the home country,political security risk of the host country,and sanctions from the West.These findings provide insights for future research:under the wave of anti-globalization and'internal circulation as the main body',resource SOEs should consider the potential risk of investment,especially keeping the middle and downstream industrial chain in China as much as possible.展开更多
In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped ...In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped product manifold has no points with the same constant sectional curvature c as the Lorentzian ambient, we show that such isometric immersion splits into warped product of isometric immersions.展开更多
Purpose:With the availability and utilization of Inter-Country Input-Output(ICIO)tables,it is possible to construct quantitative indices to assess its impact on the Global Value Chain(GVC).For the sake of visualizatio...Purpose:With the availability and utilization of Inter-Country Input-Output(ICIO)tables,it is possible to construct quantitative indices to assess its impact on the Global Value Chain(GVC).For the sake of visualization,ICIO networks with tremendous low-weight edges are too dense to show the substantial structure.These redundant edges,inevitably make the network data full of noise and eventually exert negative effects on Social Network Analysis(SNA).In this case,we need a method to filter such edges and obtain a sparser network with only the meaningful connections.Design/methodology/approach:In this paper,we propose two parameterless pruning algorithms from the global and local perspectives respectively,then the performance of them is examined using the ICIO table from different databases.Findings:The Searching Paths(SP)method extracts the strongest association paths from the global perspective,while Filtering Edges(FE)method captures the key links according to the local weight ratio.The results show that the FE method can basically include the SP method and become the best solution for the ICIO networks.Research limitations:There are still two limitations in this research.One is that the computational complexity may increase rapidly while processing the large-scale networks,so the proposed method should be further improved.The other is that much more empirical networks should be introduced to testify the scientificity and practicability of our methodology.Practical implications:The network pruning methods we proposed will promote the analysis of the ICIO network,in terms of community detection,link prediction,and spatial econometrics,etc.Also,they can be applied to many other complex networks with similar characteristics.Originality/value:This paper improves the existing research from two aspects,namely,considering the heterogeneity of weights and avoiding the interference of parameters.Therefore,it provides a new idea for the research of network backbone extraction.展开更多
Background:Gap models are individual-based models for forests.They simulate dynamic multispecies assemblages over multiple tree-generations and predict forest responses to altered environmental conditions.Their develo...Background:Gap models are individual-based models for forests.They simulate dynamic multispecies assemblages over multiple tree-generations and predict forest responses to altered environmental conditions.Their development emphases designation of the significant biological and ecological processes at appropriate time/space scales.Conceptually,they are with consistent with A.G.Tansley’s original definition of"the ecosystem".Results:An example microscale application inspects feedbacks among terrestrial vegetation change,air-quality changes from the vegetation’s release of volatile organic compounds(VOC),and climate change effects on ecosystem production of VOC’s.Gap models can allocate canopy photosynthate to the individual trees whose leaves form the vertical leaf-area profiles.VOC release depends strongly on leaf physiology by species of these trees.Leaf-level VOC emissions increase with climate-warming.Species composition change lowers the abundance of VOC-emitting taxa.In interactions among ecosystem functions and biosphere/atmosphere exchanges,community composition responses can outweigh physiological responses.This contradicts previous studies that emphasize the warming-induced impacts on leaf function.As a mesoscale example,the changes in climate(warming)on forests including pest-insect dynamics demonstrates changes on the both the tree and the insect populations.This is but one of many cases that involve using a gap model to simulate changes in spatial units typical of sampling plots and scaling these to landscape and regional levels.As this is the typical application scale for gap models,other examples are identified.The insect/climatechange can be scaled to regional consequences by simulating survey plots across a continental or subcontinental zone.Forest inventories at these scales are often conducted using independent survey plots distributed across a region.Model construction that mimics this sample design avoids the difficulties in modelling spatial interactions,but we also discuss simulation at these scales with contagion effects.Conclusions:At the global-scale,successful simulations to date have used functional types of plants,rather than tree species.In a final application,the fine-scale predictions of a gap model are compared with data from micrometeorological eddy-covariance towers and then scaled-up to produce maps of global patterns of evapotranspiration,net primary production,gross primary production and respiration.New active-remote-sensing instruments provide opportunities to test these global predictions.展开更多
Historically,ground calcined aluminas were the first high-alumina matrix products that were used in refractory formulations, in both shaped and unshaped products. At that time the flow properties of castables were enh...Historically,ground calcined aluminas were the first high-alumina matrix products that were used in refractory formulations, in both shaped and unshaped products. At that time the flow properties of castables were enhanced by the use of silica fume. This was followed later by the development of fully ground reactive aluminas which contributed to the design of the matrix below 63 μm. In addition to aggregate fines,a range of bi-modal and multi-modal reactive aluminas were also developed. These not only gave improved physical properties but also better castable workability. This paper reviews matrix alumina developments over time,from basic ground calcines to complex multi-modal matrix products and their globally standardised manufacture.展开更多
The paper points out that the science and technology, social productivity and economic form are the decisive strengths in facilitating the reformation of the production method of the manufacturing industry. This kind ...The paper points out that the science and technology, social productivity and economic form are the decisive strengths in facilitating the reformation of the production method of the manufacturing industry. This kind of strength happens through making an influence on the theory of management and science. It analyses the stage and the characteristic of the development model of manufacturing industry of human society, and on this basis does the detailed research on the several patterns of the advanced manufacturing theory and practice: the computer integrated making, concurrent engineering, lean production, agile manufacturing, planning of enterprise resources, global manufacturing. Finally, it thinks that the development model of the advanced manufacture theory and practice embodies a continuous curve of the technical innovation, which is on the basis of the theory of management science.展开更多
This paper examines Sino-US trade relations, focusing on the ongoing process of global production sharing, involving splitting of the production process into discrete activities that are then allocated across countrie...This paper examines Sino-US trade relations, focusing on the ongoing process of global production sharing, involving splitting of the production process into discrete activities that are then allocated across countries, and the resulting trade complementarities between the two countries in world manufacturing trade. The results suggest that the Sino--US trade imbalance is basically a structural phenomenon resulting from the pivotal role played by China as the final assembly centre in East Asia-centered global production networks.展开更多
Using an analytical framework of the global production network (GPN), the present paper examines the external environment and the internal dynamics of China's integrated circuit (IC) industry. We analyze the tran...Using an analytical framework of the global production network (GPN), the present paper examines the external environment and the internal dynamics of China's integrated circuit (IC) industry. We analyze the transition of China's IC industry from a state-led integrated device manufacturers' model to deeper integration into the GPN. We also explore the technological sources, the upgrading dynamics as well as the positioning of different nodes of China's IC industry in the GPN. We conclude that the "East Asia model'" of gradual industrial upgrading might not apply anymore in the new era of GPN. High-technology industries can now be upgraded based on a parallel evolution model. Policy implications for China's high-technology industrial upgrading strategies are drawn from our analysis.展开更多
Global vegetation photosynthesis and productivity have increased substantially since the 1980s,but this trend is heterogeneous in both time and space.Here,we categorize the secular trend in global vegetation greenness...Global vegetation photosynthesis and productivity have increased substantially since the 1980s,but this trend is heterogeneous in both time and space.Here,we categorize the secular trend in global vegetation greenness into sustained greening,sustained browning and greening-to-browning.We found that by 2016,increased global vegetation greenness had begun to level off,with the area of browning increasing in the last decade,reaching 39.0 million km^(2)(35.9%of the world’s vegetated area).This area is larger than the area with sustained increasing growth(27.8 million km^(2),26.4%);thus,12.0%±3.1%(0.019±0.004 NDVI a^(-1))of the previous earlier increase has been offset since 2010(2010–2016,P<0.05).Global gross primary production also leveled off,following the trend in vegetation greenness in time and space.This leveling off was caused by increasing soil water limitations due to the spatial expansion of drought,whose impact dominated over the impacts of temperature and solar radiation.This response of global gross primary production to soil water limitation was not identified by land submodels within Earth system models.Our results provide empirical evidence that global vegetation greenness and primary production are offset by water stress and suggest that as global warming continues,land submodels may overestimate the world’s capacity to take up carbon with global vegetation greening.展开更多
This paper comprehensively reviews China's openness since 1978 from three aspects: trade, foreign investment and global production sharing. We point out that the economic development of China is now standing at a hi...This paper comprehensively reviews China's openness since 1978 from three aspects: trade, foreign investment and global production sharing. We point out that the economic development of China is now standing at a historic turning point. Specifically, economic changes in China are discassed from four dimensions: (i) from China being a world assembly line to a world manufacturing powerhouse; (ii) from China being a world capital receiver to a world investor; (iii) from China being a world factory to a world market; and (iv) from the situation of "made in China" to "innovated in China." At the same time, the global economic system has also reached a turning point. A "North America-Europe-Asia " tri-polar system has formed, in which the USA, Germany and China, respectively, serve as the regional core economies.展开更多
As the global economy has become further integrated, the international production chain has become more sophisticated, with diversified stages of production located in different countries. Economic theorists have argu...As the global economy has become further integrated, the international production chain has become more sophisticated, with diversified stages of production located in different countries. Economic theorists have argued that the fragmentation of the global production chain is partly attributable to the high growth in international trade over the past several decades. In this study, we examine vertical specialization in China, Japan and Korea, and its contribution to these nations' trade. Using a multilevel model, it is illustrated that vertical specialization has encouraged increases in trade among all three countries. In particular, China 's outcome is remarkable considering how recently it became a member of the WTO.展开更多
This paper presents a detailed description of integration, quality assurance procedure, and usage of global aircraft observations for China's first generation global atmospheric reanalysis(CRA) product(1979–2018)...This paper presents a detailed description of integration, quality assurance procedure, and usage of global aircraft observations for China's first generation global atmospheric reanalysis(CRA) product(1979–2018). An integration method named "classified integration" is developed. Aircraft observations from nine different sources are integrated into the Integrated Global Meteorological Observation Archive from Aircraft(IGMOAA), a new dataset from the National Meteorological Information Center(NMIC) of the China Meteorological Administration(CMA). IGMOAA consists of global aircraft temperature, wind, and humidity data from the surface to 100 h Pa, extending from 1973 to the present. Compared with observations assimilated in the Climate Forecast System Reanalysis(CFSR) of NCEP,the observation number of IGMOAA increased by 12.9% between 2010 and 2014, mainly as a result of adding more Chinese Aircraft Meteorological Data Relay(AMDAR) data. Complex quality control procedures for aircraft observations of NCEP are applied to detect data errors. Observations are compared with ERA-Interim reanalysis from 1979 to 2018 to investigate data quality of different types and aircraft, and subsequently to develop the blacklists for CRA. IGMOAA data have been assimilated in CRA in 2018 and are real-time updated at the CMA Data-as-a-Service(CMADaa S) platform. For CRA, the fits to observations improve over time. From 1994 to 2018, root-meansquare error(RMSE) of observations relative to CRA background decreases from 1.8 to 1.0℃ for temperature above 300 h Pa, and from 4.5 to 3 m s^(-1) for zonal wind. The RMSE for humidity appears to exhibit an apparent seasonal variation with larger errors in summer and smaller ones in winter.展开更多
To identify the macroeconomic environment that has enabled China's industrial upgrading during a period of persistent renminbi appreciation,we construct a two-country New Keynesian model of industrial upgrading wi...To identify the macroeconomic environment that has enabled China's industrial upgrading during a period of persistent renminbi appreciation,we construct a two-country New Keynesian model of industrial upgrading with a global production network,endogenous firm entry,and a directed quality frontier.We show that renminbi appreciation promotes industrial upgrading without hurting real economic growth in the longer run.This holds true especially through four channels.First,the quality threshold for firm entry is lower to allow for more firms participation and thus greater product varieties(quality threshold channel).Second,upstream skill-based production uses more imported inputs of higher quality(imported input channel).Third,there is substantial global demand towards the exports of high-quality inputs(global demand channel).Fourth,domestic inputs are competing against imported inputs to broaden the scope for competition in the upstream product market to incentivize quality upgrading(scope for competition channel).展开更多
Considering snowmelt in mountainous areas as the important source of streamflow,the snow accumulation/melting processes are vital for accurate simulation of the hydrological regimes.The lack of snow-related data and i...Considering snowmelt in mountainous areas as the important source of streamflow,the snow accumulation/melting processes are vital for accurate simulation of the hydrological regimes.The lack of snow-related data and its uncertainties/conceptual ambiguity in snowpack modeling are the different challenges of developing hydroclimatological models.To tackle these challenges,Global Gridded Snow Products(GGSPs)are introduced,which effectively simplify the identification of the spatial characteristics of snow hydrological variables.This research aims to investigate the performance of multisource GGSPs using multi-stage calibration strategies in hydrological modeling.The used GGSPs were Snow-Covered Area(SCA)and Snow Water Equivalent(SWE),implemented individually or jointly to calibrate an appropriate water balance model.The study area was a mountainous watershed located in Western Iran with a considerable contribution of snowmelt to the generated streamflow.The results showed that using GGSPs as complementary information in the calibration process,besides streamflow time series,could improve the modeling accuracy compared to the conventional calibration,which is only based on streamflow data.The SCA with NSE,KGE,and RMSE values varying within the ranges of 0.47–0.57,0.54–0.65,and 4–6.88,respectively,outperformed the SWE with the corresponding metrics of 0.36–0.59,0.47–0.60,and 5.22–7.46,respectively,in simulating the total streamflow of the watershed.In addition to the superiority of the SCA over SWE,the twostage calibration strategy reduced the number of optimized parameters in each stage and the dependency of internal processes on the streamflow and improved the accuracy of the results compared with the conventional calibration strategy.On the other hand,the consistent contribution of snowmelt to the total generated streamflow(ranging from 0.9 to 1.47)and the ratio of snow melting to snowfall(ranging from 0.925 to 1.041)in different calibration strategies and models resulted in a reliable simulation of the model.展开更多
基金Zhejiang Union of Social Science,China(No.08Z24)Science Foundation of Zhejiang Sci-Tech University,China(No.1105807-Y)
文摘China apparel industry, which is deeply embedded in the global production network (GPN), faces two urgent issues, social upgrading and economic upgrading. The study of GPN places great emphasis on the two issues. Based on the survey of Ningbo apparel industry, four key components of decent work in China apparel industry are discussed. The role of buyers in promoting decent work in suppliers can't be neglected. There are significant correlations between business type and some indicators of decent work. Though the majority of the apparel firms are engaging in processing, more and more firms are involved in marketing and branding. The upgrading trajectory of China apparel industry leads to the economic and social performances.
基金the outcome of major program of the National Social Sciences Foundation Research on the Upgraded Objectives and Strategic Innovation for the Transformation and Development of Major Trading Nations(Grant No.13&ZD048)
文摘Under global production network,export cannot represent a country's gains from trade,and territory-based gains from trade refer to the remainder of export after deducting the input of intermediate goods and re-export after value-added return.Ownership-based gains from trade refer to the remainder of territory-based gains from trade after further deducting the trade in value added(TVA) realized through the inflow of foreign factors.By creating a multicountry input and output model,this paper calculates the territory-based gains from trade,ownership-based gains from trade,and territory-based gains from trade for foreign countries realized through China's export,as well as valueadded return and territory-based gains from trade for foreign countries realized through China's import.This paper has arrived at the following conclusions:behind China's status as the largest goods exporting country in the world,most of Chinese exports contribute to the gains of foreign countries;value addition for foreign countries realized through China's export and value-added return realized through China's import mostly come from Taiwan region,Japan and South Korea in East Asia;a considerable part of gains from trade for the United States realized through China-US trade is achieved through indirect trade.
文摘The International Textile Manufacturers Federation (ITMF) released its latest STATE OF TRADE REPORT Q2/2010, indicating that the strong global recovery in yarn and fabric production since their recent lows in the first quarter of 2009 continued also into the second quarter of 2010. Besides, all regions contribute to the continued recovery.
文摘In June,the Oerlikon Group released its annual Textile Report"The Fiber Year" for the tenth time.As it declared,the Asian position in world textile and apparel industry further increased at the expense of European and American activities.
基金supported by the National Key Research and Development Program of China(2022YFB3903503)the National Natural Science Foundation of China(U1901601)the Science and Technology Project of the Department of Education of Jiangxi Province,China(GJJ210541)。
文摘Various land use and land cover(LULC)products have been produced over the past decade with the development of remote sensing technology.Despite the differences in LULC classification schemes,there is a lack of research on assessing the accuracy of their application to croplands in a unified framework.Thus,this study evaluated the spatial and area accuracies of cropland classification for four commonly used global LULC products(i.e.,MCD12Q1V6,GlobCover2009,FROM-GLC and GlobeLand30)based on the harmonised FAO criterion,and quantified the relationships between four factors(i.e.,slope,elevation,field size and crop system)and cropland classification agreement.The validation results indicated that MCD12Q1 and GlobeLand30 performed well in cropland classification regarding spatial consistency,with overall accuracies of 94.90 and 93.52%,respectively.The FROMGLC showed the worst performance,with an overall accuracy of 83.17%.Overlaying the cropland generated by the four global LULC products,we found the proportions of complete agreement and disagreement were 15.51 and 44.72% for the cropland classification,respectively.High consistency was mainly observed in the Northeast China Plain,the Huang-Huai-Hai Plain and the northern part of the Middle-lower Yangtze Plain,China.In contrast,low consistency was detected primarily on the eastern edge of the northern and semiarid region,the Yunnan-Guizhou Plateau and southern China.Field size was the most important factor for mapping cropland.For area accuracy,compared with China Statistical Yearbook data at the provincial scale,the accuracies of different products in descending order were:GlobeLand30,FROM-GLC,MCD12Q1,and GlobCover2009.The cropland classification schemes mainly caused large area deviations among the four products,and they also resulted in the different ranks of spatial accuracy and area accuracy among the four products.Our results can provide valuable suggestions for selecting cropland products at the national or provincial scale and help cropland mapping and reconstruction,which is essential for food security and crop management,so they can also contribute to achieving the Sustainable Development Goals issued by the United Nations.
基金supported by National Natural Science Foundation of China(Grants No.41971198 and 42371198)Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2023-it24).
文摘In the context of economic globalization,while multinational enterprises from developed countries occupy a high-end position in the global value chain,enterprises from developing countries are often marginalized in the world market.In China,resource-based state-owned enterprises(SOEs)are tasked with the mission of safeguarding resource security,and their internationalization development ideas and strategic deployment are significantly and fundamentally different from those of other non-state-owned enterprises and large multinational corporations.This study provides ideas for the globalization policies of enterprises in developing countries.We consider J Group in western China as a case and discuss its productive investment and global production network development from 2010 to 2019.We found that J Group was‘Partly'globalized,and there are multiple core nodes with the characteristics of centralized and decentralized coexistence in the production network;in addition,the overall layout centre shifted to Southeast Asia and China;however,its global production was restricted by the enterprise's investment security considerations,support and restrictions of the home country,political security risk of the host country,and sanctions from the West.These findings provide insights for future research:under the wave of anti-globalization and'internal circulation as the main body',resource SOEs should consider the potential risk of investment,especially keeping the middle and downstream industrial chain in China as much as possible.
文摘In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped product manifold has no points with the same constant sectional curvature c as the Lorentzian ambient, we show that such isometric immersion splits into warped product of isometric immersions.
基金support from National Natural Science Foundation of China(Grant No.71971006)Humanities and Social Science Foundation of Ministry of Education of the People’s Republic of China(Grant No.19YJCGJW014).
文摘Purpose:With the availability and utilization of Inter-Country Input-Output(ICIO)tables,it is possible to construct quantitative indices to assess its impact on the Global Value Chain(GVC).For the sake of visualization,ICIO networks with tremendous low-weight edges are too dense to show the substantial structure.These redundant edges,inevitably make the network data full of noise and eventually exert negative effects on Social Network Analysis(SNA).In this case,we need a method to filter such edges and obtain a sparser network with only the meaningful connections.Design/methodology/approach:In this paper,we propose two parameterless pruning algorithms from the global and local perspectives respectively,then the performance of them is examined using the ICIO table from different databases.Findings:The Searching Paths(SP)method extracts the strongest association paths from the global perspective,while Filtering Edges(FE)method captures the key links according to the local weight ratio.The results show that the FE method can basically include the SP method and become the best solution for the ICIO networks.Research limitations:There are still two limitations in this research.One is that the computational complexity may increase rapidly while processing the large-scale networks,so the proposed method should be further improved.The other is that much more empirical networks should be introduced to testify the scientificity and practicability of our methodology.Practical implications:The network pruning methods we proposed will promote the analysis of the ICIO network,in terms of community detection,link prediction,and spatial econometrics,etc.Also,they can be applied to many other complex networks with similar characteristics.Originality/value:This paper improves the existing research from two aspects,namely,considering the heterogeneity of weights and avoiding the interference of parameters.Therefore,it provides a new idea for the research of network backbone extraction.
基金funded by the USA NASA grant NNH16ZDA001N-ESUSPIUSA NASA grant WBS:509496.02.08.09.66+5 种基金USA NASA ABoVE grant NNX17AE44GUSA DoD SERDP grant RC18-1183USA NASA grant(IDS-80NSSC17K0110)USA NSF grant(AGS-1837891)USA NSF-ATMO 1837891USA NSF Hydrologic Sciences grant 1561473。
文摘Background:Gap models are individual-based models for forests.They simulate dynamic multispecies assemblages over multiple tree-generations and predict forest responses to altered environmental conditions.Their development emphases designation of the significant biological and ecological processes at appropriate time/space scales.Conceptually,they are with consistent with A.G.Tansley’s original definition of"the ecosystem".Results:An example microscale application inspects feedbacks among terrestrial vegetation change,air-quality changes from the vegetation’s release of volatile organic compounds(VOC),and climate change effects on ecosystem production of VOC’s.Gap models can allocate canopy photosynthate to the individual trees whose leaves form the vertical leaf-area profiles.VOC release depends strongly on leaf physiology by species of these trees.Leaf-level VOC emissions increase with climate-warming.Species composition change lowers the abundance of VOC-emitting taxa.In interactions among ecosystem functions and biosphere/atmosphere exchanges,community composition responses can outweigh physiological responses.This contradicts previous studies that emphasize the warming-induced impacts on leaf function.As a mesoscale example,the changes in climate(warming)on forests including pest-insect dynamics demonstrates changes on the both the tree and the insect populations.This is but one of many cases that involve using a gap model to simulate changes in spatial units typical of sampling plots and scaling these to landscape and regional levels.As this is the typical application scale for gap models,other examples are identified.The insect/climatechange can be scaled to regional consequences by simulating survey plots across a continental or subcontinental zone.Forest inventories at these scales are often conducted using independent survey plots distributed across a region.Model construction that mimics this sample design avoids the difficulties in modelling spatial interactions,but we also discuss simulation at these scales with contagion effects.Conclusions:At the global-scale,successful simulations to date have used functional types of plants,rather than tree species.In a final application,the fine-scale predictions of a gap model are compared with data from micrometeorological eddy-covariance towers and then scaled-up to produce maps of global patterns of evapotranspiration,net primary production,gross primary production and respiration.New active-remote-sensing instruments provide opportunities to test these global predictions.
文摘Historically,ground calcined aluminas were the first high-alumina matrix products that were used in refractory formulations, in both shaped and unshaped products. At that time the flow properties of castables were enhanced by the use of silica fume. This was followed later by the development of fully ground reactive aluminas which contributed to the design of the matrix below 63 μm. In addition to aggregate fines,a range of bi-modal and multi-modal reactive aluminas were also developed. These not only gave improved physical properties but also better castable workability. This paper reviews matrix alumina developments over time,from basic ground calcines to complex multi-modal matrix products and their globally standardised manufacture.
文摘The paper points out that the science and technology, social productivity and economic form are the decisive strengths in facilitating the reformation of the production method of the manufacturing industry. This kind of strength happens through making an influence on the theory of management and science. It analyses the stage and the characteristic of the development model of manufacturing industry of human society, and on this basis does the detailed research on the several patterns of the advanced manufacturing theory and practice: the computer integrated making, concurrent engineering, lean production, agile manufacturing, planning of enterprise resources, global manufacturing. Finally, it thinks that the development model of the advanced manufacture theory and practice embodies a continuous curve of the technical innovation, which is on the basis of the theory of management science.
文摘This paper examines Sino-US trade relations, focusing on the ongoing process of global production sharing, involving splitting of the production process into discrete activities that are then allocated across countries, and the resulting trade complementarities between the two countries in world manufacturing trade. The results suggest that the Sino--US trade imbalance is basically a structural phenomenon resulting from the pivotal role played by China as the final assembly centre in East Asia-centered global production networks.
基金funding from the Ministry of Science and Technology of China and National Social Science Foundation(No.07CZZ012)
文摘Using an analytical framework of the global production network (GPN), the present paper examines the external environment and the internal dynamics of China's integrated circuit (IC) industry. We analyze the transition of China's IC industry from a state-led integrated device manufacturers' model to deeper integration into the GPN. We also explore the technological sources, the upgrading dynamics as well as the positioning of different nodes of China's IC industry in the GPN. We conclude that the "East Asia model'" of gradual industrial upgrading might not apply anymore in the new era of GPN. High-technology industries can now be upgraded based on a parallel evolution model. Policy implications for China's high-technology industrial upgrading strategies are drawn from our analysis.
基金the National Key Research and Development Program of China(2017YFA0604700)the National Natural Science Foundation of China(41722104)+3 种基金the Key Research Project of Chinese Academy of Sciences(QYZDY-SSWDQC025 and 2019DC0027)supported by the European Research Council Synergy(ERC-2013-Sy G-610028 IMBALANCE-P)the Spanish Government(CGL2016-79835)the Catalan Government(SGR 2017-1005)。
文摘Global vegetation photosynthesis and productivity have increased substantially since the 1980s,but this trend is heterogeneous in both time and space.Here,we categorize the secular trend in global vegetation greenness into sustained greening,sustained browning and greening-to-browning.We found that by 2016,increased global vegetation greenness had begun to level off,with the area of browning increasing in the last decade,reaching 39.0 million km^(2)(35.9%of the world’s vegetated area).This area is larger than the area with sustained increasing growth(27.8 million km^(2),26.4%);thus,12.0%±3.1%(0.019±0.004 NDVI a^(-1))of the previous earlier increase has been offset since 2010(2010–2016,P<0.05).Global gross primary production also leveled off,following the trend in vegetation greenness in time and space.This leveling off was caused by increasing soil water limitations due to the spatial expansion of drought,whose impact dominated over the impacts of temperature and solar radiation.This response of global gross primary production to soil water limitation was not identified by land submodels within Earth system models.Our results provide empirical evidence that global vegetation greenness and primary production are offset by water stress and suggest that as global warming continues,land submodels may overestimate the world’s capacity to take up carbon with global vegetation greening.
基金We thank Yacheng Yang and Chunrui Liu from Tsinghua University for providing very helpful research assistance. This work was supported by the National Natural Science Foundation of China (No. 71503047), the Beijing Social Science Foundation (No. 15JGC 162), and the Fundamental Research Funds for the Central Universities of the University of International Business and Economics (No. 16YQ02). 1In this paper, "China" refers to "Chinese mainland."
文摘This paper comprehensively reviews China's openness since 1978 from three aspects: trade, foreign investment and global production sharing. We point out that the economic development of China is now standing at a historic turning point. Specifically, economic changes in China are discassed from four dimensions: (i) from China being a world assembly line to a world manufacturing powerhouse; (ii) from China being a world capital receiver to a world investor; (iii) from China being a world factory to a world market; and (iv) from the situation of "made in China" to "innovated in China." At the same time, the global economic system has also reached a turning point. A "North America-Europe-Asia " tri-polar system has formed, in which the USA, Germany and China, respectively, serve as the regional core economies.
基金supported by a National R esearch Foundation of Korea grant founded by the Korean Governmenl(NRF-2010-327-B00342)
文摘As the global economy has become further integrated, the international production chain has become more sophisticated, with diversified stages of production located in different countries. Economic theorists have argued that the fragmentation of the global production chain is partly attributable to the high growth in international trade over the past several decades. In this study, we examine vertical specialization in China, Japan and Korea, and its contribution to these nations' trade. Using a multilevel model, it is illustrated that vertical specialization has encouraged increases in trade among all three countries. In particular, China 's outcome is remarkable considering how recently it became a member of the WTO.
基金Supported by the National Innovation Project for Meteorological Science and Technology (CMAGGTD003-5)China Meteorological Administration Special Public Welfare Research Fund (GYHY201506002)National Key Research and Development Program of China (2017YFC1501801)。
文摘This paper presents a detailed description of integration, quality assurance procedure, and usage of global aircraft observations for China's first generation global atmospheric reanalysis(CRA) product(1979–2018). An integration method named "classified integration" is developed. Aircraft observations from nine different sources are integrated into the Integrated Global Meteorological Observation Archive from Aircraft(IGMOAA), a new dataset from the National Meteorological Information Center(NMIC) of the China Meteorological Administration(CMA). IGMOAA consists of global aircraft temperature, wind, and humidity data from the surface to 100 h Pa, extending from 1973 to the present. Compared with observations assimilated in the Climate Forecast System Reanalysis(CFSR) of NCEP,the observation number of IGMOAA increased by 12.9% between 2010 and 2014, mainly as a result of adding more Chinese Aircraft Meteorological Data Relay(AMDAR) data. Complex quality control procedures for aircraft observations of NCEP are applied to detect data errors. Observations are compared with ERA-Interim reanalysis from 1979 to 2018 to investigate data quality of different types and aircraft, and subsequently to develop the blacklists for CRA. IGMOAA data have been assimilated in CRA in 2018 and are real-time updated at the CMA Data-as-a-Service(CMADaa S) platform. For CRA, the fits to observations improve over time. From 1994 to 2018, root-meansquare error(RMSE) of observations relative to CRA background decreases from 1.8 to 1.0℃ for temperature above 300 h Pa, and from 4.5 to 3 m s^(-1) for zonal wind. The RMSE for humidity appears to exhibit an apparent seasonal variation with larger errors in summer and smaller ones in winter.
文摘To identify the macroeconomic environment that has enabled China's industrial upgrading during a period of persistent renminbi appreciation,we construct a two-country New Keynesian model of industrial upgrading with a global production network,endogenous firm entry,and a directed quality frontier.We show that renminbi appreciation promotes industrial upgrading without hurting real economic growth in the longer run.This holds true especially through four channels.First,the quality threshold for firm entry is lower to allow for more firms participation and thus greater product varieties(quality threshold channel).Second,upstream skill-based production uses more imported inputs of higher quality(imported input channel).Third,there is substantial global demand towards the exports of high-quality inputs(global demand channel).Fourth,domestic inputs are competing against imported inputs to broaden the scope for competition in the upstream product market to incentivize quality upgrading(scope for competition channel).
文摘Considering snowmelt in mountainous areas as the important source of streamflow,the snow accumulation/melting processes are vital for accurate simulation of the hydrological regimes.The lack of snow-related data and its uncertainties/conceptual ambiguity in snowpack modeling are the different challenges of developing hydroclimatological models.To tackle these challenges,Global Gridded Snow Products(GGSPs)are introduced,which effectively simplify the identification of the spatial characteristics of snow hydrological variables.This research aims to investigate the performance of multisource GGSPs using multi-stage calibration strategies in hydrological modeling.The used GGSPs were Snow-Covered Area(SCA)and Snow Water Equivalent(SWE),implemented individually or jointly to calibrate an appropriate water balance model.The study area was a mountainous watershed located in Western Iran with a considerable contribution of snowmelt to the generated streamflow.The results showed that using GGSPs as complementary information in the calibration process,besides streamflow time series,could improve the modeling accuracy compared to the conventional calibration,which is only based on streamflow data.The SCA with NSE,KGE,and RMSE values varying within the ranges of 0.47–0.57,0.54–0.65,and 4–6.88,respectively,outperformed the SWE with the corresponding metrics of 0.36–0.59,0.47–0.60,and 5.22–7.46,respectively,in simulating the total streamflow of the watershed.In addition to the superiority of the SCA over SWE,the twostage calibration strategy reduced the number of optimized parameters in each stage and the dependency of internal processes on the streamflow and improved the accuracy of the results compared with the conventional calibration strategy.On the other hand,the consistent contribution of snowmelt to the total generated streamflow(ranging from 0.9 to 1.47)and the ratio of snow melting to snowfall(ranging from 0.925 to 1.041)in different calibration strategies and models resulted in a reliable simulation of the model.