The growth behavior of the complex intermetallic compounds(IMCs)formed at the interface of Cu/SnPbInBiSb high entropy alloy solder joints was explored.The growth inhibition mechanism of the IMCs at the Cu/SnPbInBiSb s...The growth behavior of the complex intermetallic compounds(IMCs)formed at the interface of Cu/SnPbInBiSb high entropy alloy solder joints was explored.The growth inhibition mechanism of the IMCs at the Cu/SnPbInBiSb solid−liquid reaction interface was revealed.The results showed that the growth rate of the complex IMCs obviously decreased at the Cu/SnPbInBiSb solid−liquid reaction interface.The maximum average thickness of IMCs only reached up to 1.66μm after reflowing at 200℃for 10 min.The mechanism for the slow growth of the complex IMCs was analyzed into three aspects.Firstly,the high entropy of the liquid SnPbInBiSb alloy reduced the growth rate of the complex IMCs.Secondly,the distorted lattice of complex IMCs restrained the diffusion of Cu atoms.Lastly,the higher activation energy(40.9 kJ/mol)of Cu/SnPbInBiSb solid−liquid interfacial reaction essentially impeded the growth of the complex IMCs.展开更多
The magnetization reduction of hematite using biomass waste can effectively utilize waste and reduce CO_(2) emission to achieve the goals of carbon peaking and carbon neutrality.The effects of temperatures on suspensi...The magnetization reduction of hematite using biomass waste can effectively utilize waste and reduce CO_(2) emission to achieve the goals of carbon peaking and carbon neutrality.The effects of temperatures on suspension magnetization roasting of hematite using biomass waste for evolved gases have been investigated using TG-FTIR,Py-GC/MS and gas composition analyzer.The mixture reduction process is divided into four stages.In the temperature range of 200-450℃ for mixture,the release of CO_(2),acids,and ketones is dominated in gases products.The yield and concentration of small molecules reducing gases increase when the temperature increases from 450 to 900℃.At 700℃,the volume concentrations of CO,H_(2) and CH_(4) peak at 8.91%,8.90% and 4.91%,respectively.During the suspension magnetization roasting process,an optimal iron concentrate with an iron grade of 70.86%,a recovery of 98.66% and a magnetic conversion of 45.70% is obtained at 700℃.Therefore,the magnetization reduction could react greatly in the temperature range of 600 to 700℃ owing to the suitable reducing gases.This study shows a detail gaseous evolution of roasting temperature and provides a new insight for studying the reduction process of hematite using biomass waste.展开更多
Natural condition in Western China is relatively poor and regional economy level is low. The ecological environment has been seriously damaged by population growth and over-exploitation of natural resources. It is ver...Natural condition in Western China is relatively poor and regional economy level is low. The ecological environment has been seriously damaged by population growth and over-exploitation of natural resources. It is very important for coordinating the regional development and safeguarding ecological security to discuss the eco-environment evolution trend and its sustainable development strategies in Western China. Based on analyzing documents and relative research,the changes of main ecological and environmental problems in the western region,such as degradation of forest and grassland ecosystems,shrinkage of wetland,desertification,water and soil erosion,etc. were synthetically discussed. Then,according to the development trend,some countermeasures for eco-environment protection and rehabilitation and sustainable development were proposed.展开更多
Al-Ti diffusion couples were made by embedded technology and treated at the temperature between the melting points of Al and Ti. The microstructure evolution and growth mechanism of the Al-Ti DRZ were investigated. Th...Al-Ti diffusion couples were made by embedded technology and treated at the temperature between the melting points of Al and Ti. The microstructure evolution and growth mechanism of the Al-Ti DRZ were investigated. The result shows that the DRZ, the mixture of TiAl3 and Al, grows layer by layer along their chemical equilibrium zone. In the course, the growth interface moves toward the aluminum side. TiAl3 is the only new phase which forms earliest in the course of heat-treatment. The growth mechanism of the DRZ changes after the phase transition of titanium. Before the phase transition of titanium, the growth of the DRZ is controlled by the dissolution speed of the titanium to the molten aluminum, while after the phase transition of titanium, the growth is controlled by the chemical reaction speed of Al and Ti atoms, and consequently, its growth rate is greatly increased.展开更多
The microbiotic crust study is among new focuses in investigating on the desertification control. Based on determination of algal crusts with different successive ages (4-, 8-, 17-, 34-, 42-year-old) and unconsolidate...The microbiotic crust study is among new focuses in investigating on the desertification control. Based on determination of algal crusts with different successive ages (4-, 8-, 17-, 34-, 42-year-old) and unconsolidated sand in the desert area, species composition and clustering analyses were carried out in this study. Results on successional orientation revealed that (1) the abundance of Cyanophyta, specially of Scytonema javanicum gradually decreased; (2) the abundance of Chlorophyta, Bacillariophyta and a species of Cyanophyta, Phormidium tenue increased; (3) the biodiversity increased gradually with the community succession; and (4) biomass of microalgae increased at the early stage, but decreased at the later stage due to the abundance of lichens and mosses. But, the speed of natural succession was so slow that the community-building species was still the first dominant species after 42 years, except that its dominant degree decreased just slightly. However, successive speed and trend were affected by water, vegetation coverage, terrain, time and soil physico-chemical properties as well, especially Mn content in the soil appeared to have a threshold effect.展开更多
[Objective] The paper was to explore the vegetation regressive succession law in arid zone of central Ningxia.[Method] Based on the survey data during 1982-2001,the grass type vegetation characteristics,grassland prod...[Objective] The paper was to explore the vegetation regressive succession law in arid zone of central Ningxia.[Method] Based on the survey data during 1982-2001,the grass type vegetation characteristics,grassland productivity and the quality of grass in 7 survey sites were analyzed.[Result] The grass type in arid zone of central Ningxia had changed or was changing in the last 20 years;the dominant species within communities were also replacing by other species,vegetation coverage and number of plant species within communities were continuously declined,the bearing capacity of grassland had averagely declined by 114%,and the quality of grassland seriously declined.[Conclusion] The study provided basic data for the sustainable use of typical grassland.展开更多
基金supported by the National Natural Science Foundation of China (No.U2241223)the Heilongjiang Touyan Innovation Team Program,China (No.HITTY-20190013)the Fundamental Research Funds for the Central Universities,China (No.AUEA5770400622)。
文摘The growth behavior of the complex intermetallic compounds(IMCs)formed at the interface of Cu/SnPbInBiSb high entropy alloy solder joints was explored.The growth inhibition mechanism of the IMCs at the Cu/SnPbInBiSb solid−liquid reaction interface was revealed.The results showed that the growth rate of the complex IMCs obviously decreased at the Cu/SnPbInBiSb solid−liquid reaction interface.The maximum average thickness of IMCs only reached up to 1.66μm after reflowing at 200℃for 10 min.The mechanism for the slow growth of the complex IMCs was analyzed into three aspects.Firstly,the high entropy of the liquid SnPbInBiSb alloy reduced the growth rate of the complex IMCs.Secondly,the distorted lattice of complex IMCs restrained the diffusion of Cu atoms.Lastly,the higher activation energy(40.9 kJ/mol)of Cu/SnPbInBiSb solid−liquid interfacial reaction essentially impeded the growth of the complex IMCs.
基金Project(52022019)supported by the National Natural Science Foundation of China。
文摘The magnetization reduction of hematite using biomass waste can effectively utilize waste and reduce CO_(2) emission to achieve the goals of carbon peaking and carbon neutrality.The effects of temperatures on suspension magnetization roasting of hematite using biomass waste for evolved gases have been investigated using TG-FTIR,Py-GC/MS and gas composition analyzer.The mixture reduction process is divided into four stages.In the temperature range of 200-450℃ for mixture,the release of CO_(2),acids,and ketones is dominated in gases products.The yield and concentration of small molecules reducing gases increase when the temperature increases from 450 to 900℃.At 700℃,the volume concentrations of CO,H_(2) and CH_(4) peak at 8.91%,8.90% and 4.91%,respectively.During the suspension magnetization roasting process,an optimal iron concentrate with an iron grade of 70.86%,a recovery of 98.66% and a magnetic conversion of 45.70% is obtained at 700℃.Therefore,the magnetization reduction could react greatly in the temperature range of 600 to 700℃ owing to the suitable reducing gases.This study shows a detail gaseous evolution of roasting temperature and provides a new insight for studying the reduction process of hematite using biomass waste.
基金Supported by National Key Technology R&D Program during the 11th Five-year Plan (2006BAC01A01)~~
文摘Natural condition in Western China is relatively poor and regional economy level is low. The ecological environment has been seriously damaged by population growth and over-exploitation of natural resources. It is very important for coordinating the regional development and safeguarding ecological security to discuss the eco-environment evolution trend and its sustainable development strategies in Western China. Based on analyzing documents and relative research,the changes of main ecological and environmental problems in the western region,such as degradation of forest and grassland ecosystems,shrinkage of wetland,desertification,water and soil erosion,etc. were synthetically discussed. Then,according to the development trend,some countermeasures for eco-environment protection and rehabilitation and sustainable development were proposed.
基金Project (ZR2011EL023) supported by the Natural Science Foundation of Shandong Province,ChinaProject (12CX04057A) supported by the Fundamental Research Funds for the Central Universities,China
文摘Al-Ti diffusion couples were made by embedded technology and treated at the temperature between the melting points of Al and Ti. The microstructure evolution and growth mechanism of the Al-Ti DRZ were investigated. The result shows that the DRZ, the mixture of TiAl3 and Al, grows layer by layer along their chemical equilibrium zone. In the course, the growth interface moves toward the aluminum side. TiAl3 is the only new phase which forms earliest in the course of heat-treatment. The growth mechanism of the DRZ changes after the phase transition of titanium. Before the phase transition of titanium, the growth of the DRZ is controlled by the dissolution speed of the titanium to the molten aluminum, while after the phase transition of titanium, the growth is controlled by the chemical reaction speed of Al and Ti atoms, and consequently, its growth rate is greatly increased.
文摘The microbiotic crust study is among new focuses in investigating on the desertification control. Based on determination of algal crusts with different successive ages (4-, 8-, 17-, 34-, 42-year-old) and unconsolidated sand in the desert area, species composition and clustering analyses were carried out in this study. Results on successional orientation revealed that (1) the abundance of Cyanophyta, specially of Scytonema javanicum gradually decreased; (2) the abundance of Chlorophyta, Bacillariophyta and a species of Cyanophyta, Phormidium tenue increased; (3) the biodiversity increased gradually with the community succession; and (4) biomass of microalgae increased at the early stage, but decreased at the later stage due to the abundance of lichens and mosses. But, the speed of natural succession was so slow that the community-building species was still the first dominant species after 42 years, except that its dominant degree decreased just slightly. However, successive speed and trend were affected by water, vegetation coverage, terrain, time and soil physico-chemical properties as well, especially Mn content in the soil appeared to have a threshold effect.
基金Supported by Key Scientific and Technological Projects in Ningxia Hui Autonomous Region"Research and Demonstration of Sustain-able Utilization Technology in Arid and Semiarid Grassland in Ningxia Hui Autonomous Region"~~
文摘[Objective] The paper was to explore the vegetation regressive succession law in arid zone of central Ningxia.[Method] Based on the survey data during 1982-2001,the grass type vegetation characteristics,grassland productivity and the quality of grass in 7 survey sites were analyzed.[Result] The grass type in arid zone of central Ningxia had changed or was changing in the last 20 years;the dominant species within communities were also replacing by other species,vegetation coverage and number of plant species within communities were continuously declined,the bearing capacity of grassland had averagely declined by 114%,and the quality of grassland seriously declined.[Conclusion] The study provided basic data for the sustainable use of typical grassland.
