The huge migration of rural workers has new characteristics such as the bad order, high degree of concentration, low level of collective action, marginality in social status, unfair treatment, difficult integration of...The huge migration of rural workers has new characteristics such as the bad order, high degree of concentration, low level of collective action, marginality in social status, unfair treatment, difficult integration of the new generation, and the new return trend of rural migrants, which causes ‘urban diseases’ in China. Countermeasures should be taken to develop medium-sized and small cities, integrate the labor market of the city and countryside, provide necessary public services, social security and vocational training, guide the rural migrant workers to return rationally, and help the new generation live in harmony with urban residents.展开更多
Transformation and reform are two major themes of China's urbanization at the present stage.This paper argues that population urbanization,which lags behind land urbanization,is ignored in the process of tradition...Transformation and reform are two major themes of China's urbanization at the present stage.This paper argues that population urbanization,which lags behind land urbanization,is ignored in the process of traditional urbanization.The most important transformation of urbanization is citizenship process for rural migrants who have been semiurbanized.In order to promote urban transformation,a coordinated improving reform must consider the following basic issues:population,financing,land and urban system.展开更多
On November 12,Chinese Premier Li Keqiang and Singaporean Prime Minister Lee Hsien Loong witnessed representatives of their respective governments sign Protocol to Upgrade the Free Trade Agreement in Singapore.The sig...On November 12,Chinese Premier Li Keqiang and Singaporean Prime Minister Lee Hsien Loong witnessed representatives of their respective governments sign Protocol to Upgrade the Free Trade Agreement in Singapore.The signing of the protocol heralds deepening of economic and trade relations between the two countries-the most important and substantial achievement China has made in the construction of free trade areas.This is also the third upgraded bilateral free trade agreement(FTA)China has signed with foreign partners after agreements with ASEAN and Chile.展开更多
The water depth in Nansha（南沙） waters,which is located in the southern South China Sea,varies from 200 to 2 500 m,with a deep-water（500 m） area of 500 000 km2.In this region,there are many depositional basins wit...The water depth in Nansha（南沙） waters,which is located in the southern South China Sea,varies from 200 to 2 500 m,with a deep-water（500 m） area of 500 000 km2.In this region,there are many depositional basins with various structural features,prone to the accumulation of organic material.The temperature and pressure conditions in the deep-water environment are suitable for the preservation of gas hydrate.At several sites,we have recognized bottom-simulating reflectors（BSRs） from seismic data.Regional geology analyses show that the Nansha waters may have abundant gas hy-drate prospects,especially in localities such as the Nansha trough and other deep-water basins of the central Nansha waters.展开更多
The iron element in electric arc furnace(EAF)slag is extremely difficult to recycle due to the low specific magnetic susceptibility of the RO phase(a solid solution of FeO,MgO,CaO,and MnO).Landfilling EAF slag is stri...The iron element in electric arc furnace(EAF)slag is extremely difficult to recycle due to the low specific magnetic susceptibility of the RO phase(a solid solution of FeO,MgO,CaO,and MnO).Landfilling EAF slag is strictly forbidden for environmental consideration because of poisonous Cr^(6+) leaching.The original RO phase could be transformed to a spinel structure,whose specific magnetic susceptibility is much higher than that of other minerals,through hot modification,resulting in significantly increased iron recovery by magnetic separation.Precipitation of spinel crystals encloses chromium,such that iron and chromium could be recovered simultaneously.The chromium in obtained iron concentrates is considerably useful for stainless steel making rather than polluting the environment.As a result,recovering iron and chromium is truly beneficial for cleaner production.Hot modification of EAF slag should be conducted at 1500-1600ºC for at least 60 min to guarantee homogeneous liquid slag.The liquid slag was poured onto an iron mold to obtain modified slag(MS)through air quenching.MS was characterized by thermodynamic analysis,X-ray diffraction,and scanning electron microscopy combined with energy-dispersive spectroscopy to correlate the relationship between mineral structures and iron recovery.The iron recovery rate of MS first increased and then decreased with increasing modifier.It was less than 10%when the modifier addition amount was below 12 wt.%,but it increased rapidly as the modifier addition amount increased from 16 to 24 wt.%,mainly due to spinel formation.The highest iron recovery rate was 81.9%when the modifier amount reached 20 wt.%.Meanwhile,Cr^(6+) was enriched in the spinel phase but was not observed in other minerals.Industrial tests were performed on-site with the modifier ranging from 12 to 18 wt.%because additional heat was not provided during the tests.Results showed that MS with 18 wt.%modifier addition exhibited an iron recovery rate of 61.0%,much higher than that(34.6%)of the original slag.展开更多
文摘The huge migration of rural workers has new characteristics such as the bad order, high degree of concentration, low level of collective action, marginality in social status, unfair treatment, difficult integration of the new generation, and the new return trend of rural migrants, which causes ‘urban diseases’ in China. Countermeasures should be taken to develop medium-sized and small cities, integrate the labor market of the city and countryside, provide necessary public services, social security and vocational training, guide the rural migrant workers to return rationally, and help the new generation live in harmony with urban residents.
文摘Transformation and reform are two major themes of China's urbanization at the present stage.This paper argues that population urbanization,which lags behind land urbanization,is ignored in the process of traditional urbanization.The most important transformation of urbanization is citizenship process for rural migrants who have been semiurbanized.In order to promote urban transformation,a coordinated improving reform must consider the following basic issues:population,financing,land and urban system.
文摘On November 12,Chinese Premier Li Keqiang and Singaporean Prime Minister Lee Hsien Loong witnessed representatives of their respective governments sign Protocol to Upgrade the Free Trade Agreement in Singapore.The signing of the protocol heralds deepening of economic and trade relations between the two countries-the most important and substantial achievement China has made in the construction of free trade areas.This is also the third upgraded bilateral free trade agreement(FTA)China has signed with foreign partners after agreements with ASEAN and Chile.
基金supported by the National Basic Research Programs of China (973 Programs) (Nos. 2009CB2194 and 2007CB411700)the National Natural Science Fundation of China (Nos. 40976029 and 40676039)+2 种基金the Major Knowledge Innovation Program of Chinese Academy of Sciences (No. kzcx2-yw-203-01)the National Program of Sustaining Science and Technology (No. 2006BAB19B00)the Ministry of Land and Resources, China (Nos. GT-YQ-QQ-2008-1-02 and 2009GYXQ06)
文摘The water depth in Nansha（南沙） waters,which is located in the southern South China Sea,varies from 200 to 2 500 m,with a deep-water（500 m） area of 500 000 km2.In this region,there are many depositional basins with various structural features,prone to the accumulation of organic material.The temperature and pressure conditions in the deep-water environment are suitable for the preservation of gas hydrate.At several sites,we have recognized bottom-simulating reflectors（BSRs） from seismic data.Regional geology analyses show that the Nansha waters may have abundant gas hy-drate prospects,especially in localities such as the Nansha trough and other deep-water basins of the central Nansha waters.
基金supported by Sichuan Province Science_and Technology Program(201904a05020008)Anhui Province Science and Technology Program(2019YFSY0029)the Open Project Funding from State Key Laboratory of Solid Waste Reuse for Building Materials(No.SWR-2017-005).
文摘The iron element in electric arc furnace(EAF)slag is extremely difficult to recycle due to the low specific magnetic susceptibility of the RO phase(a solid solution of FeO,MgO,CaO,and MnO).Landfilling EAF slag is strictly forbidden for environmental consideration because of poisonous Cr^(6+) leaching.The original RO phase could be transformed to a spinel structure,whose specific magnetic susceptibility is much higher than that of other minerals,through hot modification,resulting in significantly increased iron recovery by magnetic separation.Precipitation of spinel crystals encloses chromium,such that iron and chromium could be recovered simultaneously.The chromium in obtained iron concentrates is considerably useful for stainless steel making rather than polluting the environment.As a result,recovering iron and chromium is truly beneficial for cleaner production.Hot modification of EAF slag should be conducted at 1500-1600ºC for at least 60 min to guarantee homogeneous liquid slag.The liquid slag was poured onto an iron mold to obtain modified slag(MS)through air quenching.MS was characterized by thermodynamic analysis,X-ray diffraction,and scanning electron microscopy combined with energy-dispersive spectroscopy to correlate the relationship between mineral structures and iron recovery.The iron recovery rate of MS first increased and then decreased with increasing modifier.It was less than 10%when the modifier addition amount was below 12 wt.%,but it increased rapidly as the modifier addition amount increased from 16 to 24 wt.%,mainly due to spinel formation.The highest iron recovery rate was 81.9%when the modifier amount reached 20 wt.%.Meanwhile,Cr^(6+) was enriched in the spinel phase but was not observed in other minerals.Industrial tests were performed on-site with the modifier ranging from 12 to 18 wt.%because additional heat was not provided during the tests.Results showed that MS with 18 wt.%modifier addition exhibited an iron recovery rate of 61.0%,much higher than that(34.6%)of the original slag.
