Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain uncl...Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain unclear.This study aimed to identify the spatial changes in water quality and the driving factors of seven lakes(Juyanhai Lake,Ulansuhai Lake,Hongjiannao Lake,Daihai Lake,Chagannaoer Lake,Hulun Lake,and Wulannuoer Lake)across the longitudinal axis(from the west to the east)of Inner Mongolia.Large-scale research was conducted using the comprehensive trophic level index(TLI(Σ)),multivariate statistics,and spatial analysis methods.The results showed that most lakes in Inner Mongolia were weakly alkaline.Total dissolved solids and salinity of lake water showed obvious zonation characteristics.Nitrogen and phosphorus were identified as the main pollutants in lakes,with high average concentrations of total nitrogen and total phosphorus being of 4.05 and 0.21 mg/L,respectively.The values of TLI(Σ)ranged from 49.14 to 71.77,indicating varying degrees of lake eutrophication,and phosphorus was the main driver of lake eutrophication.The lakes of Inner Mongolia could be categorized into lakes to the west of Daihai Lake and lakes to the east of Daihai Lake in terms of salinity and TLI(Σ).The salinity levels of lakes to the west of Daihai Lake exceeded those of lakes to the east of Daihai Lake,whereas the opposite trend was observed for lake trophic level.The intensity and mode of anthropogenic activities were the driving factors of the spatial patterns of lake water quality.It is recommended to control the impact of anthropogenic activities on the water quality of lakes in Inner Mongolia to improve lake ecological environment.These findings provide a more thorough understanding of the driving mechanism of the spatial patterns of water quality in lakes of Inner Mongolia,which can be used to develop strategies for lake ecosystem protection and water resources management in this region.展开更多
In order to meet the developing requirements for the output and quality of the products of Baosteel, the No. 4 slab continuous caster designed by the Danieli Company of Italy was built. Since starting up in December, ...In order to meet the developing requirements for the output and quality of the products of Baosteel, the No. 4 slab continuous caster designed by the Danieli Company of Italy was built. Since starting up in December, 2006, the casting machine has run smoothly in the aspects of production and quality control. It is equipped with advanced apparatus and technology, such as electric magnetic braking （EMBR） and soft reduction. Some operation indices have been continually improved, in order to ensure that slab quality meets the requirements of downstream products. Its total output reached 2.17 Mt in 2007. This study analyzes the operational indices and the slab quality.展开更多
Electrochemical trepanning(ECTr)is an effective electrochemical machining(ECM)technique that can be used to manufacture the integral components of aero-engine compressors.This study focused on the dynamic evolution of...Electrochemical trepanning(ECTr)is an effective electrochemical machining(ECM)technique that can be used to manufacture the integral components of aero-engine compressors.This study focused on the dynamic evolution of ECTr for production of inner blisks(bladed disks)with a special chamfer structure at blade tip.Due to the existence of chamfer,the ECTr process of inner blades is in a non-equilibrium state during the early stages,and the physical field changes in the machining gap are complex,making it difficult to predict the forming process.In this paper,a dynamic evolution model(DEM)of inner blade ECTr with a special chamfer at blade tip structure is proposed,and an ECTr multi-physical fields simulation study was carried out.The evolution of the chamfer at blade tip was analyzed and data related to chamfer were predicted based on the dependence of anode boundary properties with machining time and feed rate.In addition,the dis-tributions of current density,electrolyte flow rate,bubble volume fraction,temperature rise,and electrolyte conductivity in the machining area at different times were obtained by combining them with the multi-physical fields simulation results.Subsequently,a series of ECTr experiments were conducted,in which,as the feed rate increased,the surface quality and machining accuracy of the inner blades were improved.Compared with the simulation results,the error in machining accu-racy of the chamfer profile is controlled within±2%,and the machining accuracy of the blade full profile was controlled within±0.2 mm,indicating that the model proposed in this study was effec-tive in predicting the evolution of inner blades ECTr with chamfer structures at blade tip.展开更多
A new linear integration was developed. First, effective strain rate for slab forging with bulge was expressed in terms of two-dimensional strain rate vector, and its inner-product was integrated term by term. Second,...A new linear integration was developed. First, effective strain rate for slab forging with bulge was expressed in terms of two-dimensional strain rate vector, and its inner-product was integrated term by term. Second, a summation process of term by term integrated results and a formula of the bulging were introduced, and an analytical solution of stress effective factor was obtained. It is proved that the expression of power by the above linear integration is the same as that of traditional immediate integration. Also, the solution was simplified by series expansion and compared by slab forging test with the others. It turns out that the calculated result of total forging pressure is basically in agreement with measured value in the actual press test.展开更多
基金funded by the National Key Research and Development Program of China(2021YFC3201203)the Major Science and Technology Projects of Inner Mongolia Autonomous Region(2020ZD0009)+2 种基金the National Natural Science Foundation of China(51869014)the Open Project Program of the Ministry of Education Key Laboratory of Ecology and Resources Use of the Mongolian Plateau(KF2020006)the Special Funds for Innovation and Entrepreneurship of Postgraduates in Inner Mongolia University(11200-121024).
文摘Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain unclear.This study aimed to identify the spatial changes in water quality and the driving factors of seven lakes(Juyanhai Lake,Ulansuhai Lake,Hongjiannao Lake,Daihai Lake,Chagannaoer Lake,Hulun Lake,and Wulannuoer Lake)across the longitudinal axis(from the west to the east)of Inner Mongolia.Large-scale research was conducted using the comprehensive trophic level index(TLI(Σ)),multivariate statistics,and spatial analysis methods.The results showed that most lakes in Inner Mongolia were weakly alkaline.Total dissolved solids and salinity of lake water showed obvious zonation characteristics.Nitrogen and phosphorus were identified as the main pollutants in lakes,with high average concentrations of total nitrogen and total phosphorus being of 4.05 and 0.21 mg/L,respectively.The values of TLI(Σ)ranged from 49.14 to 71.77,indicating varying degrees of lake eutrophication,and phosphorus was the main driver of lake eutrophication.The lakes of Inner Mongolia could be categorized into lakes to the west of Daihai Lake and lakes to the east of Daihai Lake in terms of salinity and TLI(Σ).The salinity levels of lakes to the west of Daihai Lake exceeded those of lakes to the east of Daihai Lake,whereas the opposite trend was observed for lake trophic level.The intensity and mode of anthropogenic activities were the driving factors of the spatial patterns of lake water quality.It is recommended to control the impact of anthropogenic activities on the water quality of lakes in Inner Mongolia to improve lake ecological environment.These findings provide a more thorough understanding of the driving mechanism of the spatial patterns of water quality in lakes of Inner Mongolia,which can be used to develop strategies for lake ecosystem protection and water resources management in this region.
文摘In order to meet the developing requirements for the output and quality of the products of Baosteel, the No. 4 slab continuous caster designed by the Danieli Company of Italy was built. Since starting up in December, 2006, the casting machine has run smoothly in the aspects of production and quality control. It is equipped with advanced apparatus and technology, such as electric magnetic braking （EMBR） and soft reduction. Some operation indices have been continually improved, in order to ensure that slab quality meets the requirements of downstream products. Its total output reached 2.17 Mt in 2007. This study analyzes the operational indices and the slab quality.
基金the National Nature Science Foundation of China (52275435)the National Natural Science Foundation of China for Creative Research Groups (51921003)the National Science and Technology Major Project (2017-VII-0004-0097).
文摘Electrochemical trepanning(ECTr)is an effective electrochemical machining(ECM)technique that can be used to manufacture the integral components of aero-engine compressors.This study focused on the dynamic evolution of ECTr for production of inner blisks(bladed disks)with a special chamfer structure at blade tip.Due to the existence of chamfer,the ECTr process of inner blades is in a non-equilibrium state during the early stages,and the physical field changes in the machining gap are complex,making it difficult to predict the forming process.In this paper,a dynamic evolution model(DEM)of inner blade ECTr with a special chamfer at blade tip structure is proposed,and an ECTr multi-physical fields simulation study was carried out.The evolution of the chamfer at blade tip was analyzed and data related to chamfer were predicted based on the dependence of anode boundary properties with machining time and feed rate.In addition,the dis-tributions of current density,electrolyte flow rate,bubble volume fraction,temperature rise,and electrolyte conductivity in the machining area at different times were obtained by combining them with the multi-physical fields simulation results.Subsequently,a series of ECTr experiments were conducted,in which,as the feed rate increased,the surface quality and machining accuracy of the inner blades were improved.Compared with the simulation results,the error in machining accu-racy of the chamfer profile is controlled within±2%,and the machining accuracy of the blade full profile was controlled within±0.2 mm,indicating that the model proposed in this study was effec-tive in predicting the evolution of inner blades ECTr with chamfer structures at blade tip.
文摘A new linear integration was developed. First, effective strain rate for slab forging with bulge was expressed in terms of two-dimensional strain rate vector, and its inner-product was integrated term by term. Second, a summation process of term by term integrated results and a formula of the bulging were introduced, and an analytical solution of stress effective factor was obtained. It is proved that the expression of power by the above linear integration is the same as that of traditional immediate integration. Also, the solution was simplified by series expansion and compared by slab forging test with the others. It turns out that the calculated result of total forging pressure is basically in agreement with measured value in the actual press test.
