The changes of one region’s trade barriers will affect other regions’trade volume.These spatial correlations caused by explanatory variables also constitute another part of“the multilateral resistance”,which tend ...The changes of one region’s trade barriers will affect other regions’trade volume.These spatial correlations caused by explanatory variables also constitute another part of“the multilateral resistance”,which tend to be ignored in traditional gravity equations.This paper takes this inconsistency between theoretical basis and empirical analysis as the breakthrough point of research.A multilateral gravity model is built,which has the feature of generalized spatial correlation.Then,frontier techniques of spatial econometrics are used to construct an empirical equation,and to conduct an empirical analysis,which scientifically estimate the magnitudes of bilateral direct impacts and the magnitudes of spatial spillovers on multilateral neighbors.The decomposition of the effects that provides reference for the directional operations of trade policy shows as follows:The negative factors that have significant spatial spillover effects would bring about multilateral resistance on China-Africa agricultural trade,which are caused by relatively poor social and economic conditions,corruption,and ethnic conflicts in some African countries.Energy production may cause crowding-out effects on agriculture of neighboring regions.In addition,the conflicts between African countries would hinder the development of agricultural trade between China and African countries not only because they have negative direct impacts on China-African agricultural trade but also because they have significant spatial spillover effects.When China promotes China-Africa agricultural trade by means of investment or aid,China should pay close attention to some direct or indirect impacts on the stable development of the China-African agricultural trade,which are caused by factors such as the developments of non-agricultural industries,peace,cultural consensus and efficient government.展开更多
Gangue from underground separation of coal can directly be used for filling mined out areas, saving transport capacity and reducing the amount of waste polluting the environment above the ground. We introduced a struc...Gangue from underground separation of coal can directly be used for filling mined out areas, saving transport capacity and reducing the amount of waste polluting the environment above the ground. We introduced a structure and operating principle of an underground direct-impact sieving device by which a separation experiment was carried out. By means of high speed conveyer belts, coal and gangue impacted the breaking board at high speeds ranging from 6 to 14 m/s. Given the differences of hardness between coal and gangue, after selective crushing, the gangue with the higher hardness was crushed less and coal with lower hardness crushed more, which could be separated by a 50 mm sieving plate. The material above the sieving plate was disposed of as gangue and the material below as coal. The results indicate that the crush ratio below the 50 mm sieving plate increases linearly with an increase in impact velocity and decays exponentially with an increase in hardness. Employing this equipment to separate coal and gangue, the hardness of coal f should be <2. This separation device provides relatively good effect in separating coal and gangue with a relatively wide difference of hardness.展开更多
A comparison of direct integration methods is madeand their efficiency is investigated for impact problems.New-mark,Wilson-θ,Central Difference and Houbolt Methodsare used as direct integration methods.Impact analysi...A comparison of direct integration methods is madeand their efficiency is investigated for impact problems.New-mark,Wilson-θ,Central Difference and Houbolt Methodsare used as direct integration methods.Impact analysisincludes that of elastic and large deformation based uponupdated Lagrangian including buckling check.The resultsshow that the direct integration methods give differentresults in different contact-impact cases.展开更多
Preventive treatment has an essential effect on latent tuberculosis infection(LTBI)[purified protein derivative(PPD)induration≥15 mm].Between2010 and 2013,there were 6 tuberculosis(TB)outbreaks in the universities in...Preventive treatment has an essential effect on latent tuberculosis infection(LTBI)[purified protein derivative(PPD)induration≥15 mm].Between2010 and 2013,there were 6 tuberculosis(TB)outbreaks in the universities in Dalian,China.So far,in Dalian,the directly observed therapy(DOT)and展开更多
文摘The changes of one region’s trade barriers will affect other regions’trade volume.These spatial correlations caused by explanatory variables also constitute another part of“the multilateral resistance”,which tend to be ignored in traditional gravity equations.This paper takes this inconsistency between theoretical basis and empirical analysis as the breakthrough point of research.A multilateral gravity model is built,which has the feature of generalized spatial correlation.Then,frontier techniques of spatial econometrics are used to construct an empirical equation,and to conduct an empirical analysis,which scientifically estimate the magnitudes of bilateral direct impacts and the magnitudes of spatial spillovers on multilateral neighbors.The decomposition of the effects that provides reference for the directional operations of trade policy shows as follows:The negative factors that have significant spatial spillover effects would bring about multilateral resistance on China-Africa agricultural trade,which are caused by relatively poor social and economic conditions,corruption,and ethnic conflicts in some African countries.Energy production may cause crowding-out effects on agriculture of neighboring regions.In addition,the conflicts between African countries would hinder the development of agricultural trade between China and African countries not only because they have negative direct impacts on China-African agricultural trade but also because they have significant spatial spillover effects.When China promotes China-Africa agricultural trade by means of investment or aid,China should pay close attention to some direct or indirect impacts on the stable development of the China-African agricultural trade,which are caused by factors such as the developments of non-agricultural industries,peace,cultural consensus and efficient government.
基金the Natural Science Foundation of Jiangsu Province (No.BK2009098)
文摘Gangue from underground separation of coal can directly be used for filling mined out areas, saving transport capacity and reducing the amount of waste polluting the environment above the ground. We introduced a structure and operating principle of an underground direct-impact sieving device by which a separation experiment was carried out. By means of high speed conveyer belts, coal and gangue impacted the breaking board at high speeds ranging from 6 to 14 m/s. Given the differences of hardness between coal and gangue, after selective crushing, the gangue with the higher hardness was crushed less and coal with lower hardness crushed more, which could be separated by a 50 mm sieving plate. The material above the sieving plate was disposed of as gangue and the material below as coal. The results indicate that the crush ratio below the 50 mm sieving plate increases linearly with an increase in impact velocity and decays exponentially with an increase in hardness. Employing this equipment to separate coal and gangue, the hardness of coal f should be <2. This separation device provides relatively good effect in separating coal and gangue with a relatively wide difference of hardness.
文摘A comparison of direct integration methods is madeand their efficiency is investigated for impact problems.New-mark,Wilson-θ,Central Difference and Houbolt Methodsare used as direct integration methods.Impact analysisincludes that of elastic and large deformation based uponupdated Lagrangian including buckling check.The resultsshow that the direct integration methods give differentresults in different contact-impact cases.
文摘Preventive treatment has an essential effect on latent tuberculosis infection(LTBI)[purified protein derivative(PPD)induration≥15 mm].Between2010 and 2013,there were 6 tuberculosis(TB)outbreaks in the universities in Dalian,China.So far,in Dalian,the directly observed therapy(DOT)and
