The rural settlement is one of important aspects to understand regional human-environment relationships. Zhangjiakou city, located in the poverty belt around Beijing and Tianjin, was used as an example to analyze the ...The rural settlement is one of important aspects to understand regional human-environment relationships. Zhangjiakou city, located in the poverty belt around Beijing and Tianjin, was used as an example to analyze the evolution of rural settlements during 1985–2010 through the use of statistical and spatial analysis methods. The results demonstrate the following:(1) the area of rural settlements expanded from 665.76 to 928.14 km2 during 1985–2010. Rural settlements in prefecture city of Zhangjiakou were significantly agglomerated in terms of their spatial distribution, which presented an approximately normal distribution over the entire period. Rural settlements were usually distributed within regions where the terrain niche had an elevation of between 900 and 1500 m, and a slope from 5? to 20?;(2) there were significant regional differences in the density and size distribution of rural settlements in Zhangjiakou. The density of rural settlements in 2010 was higher than that in 1985, while there was a clustered distribution of rural settlements in 2010. There was a significant high value cluster in the size distribution, and a local negative correlation between the size and density distribution of rural settlements in Zhangjiakou;(3) rural economic development, investment in agricultural technology, and infrastructure improvement played important roles in the evolution of rural settlements. There were spatial differences in the relationship between the distribution of rural settlements and socio-economic factors in Zhangjiakou. This study provides practical guidance for the achievement of urban and rural integration development and the promotion of a new form of countryside construction.展开更多
The thermal equilibrium state of the reference electrode was investigated. The results show that the temperature difference between the inside and the outside of zirconia tube was very small and the Seebeck effect can...The thermal equilibrium state of the reference electrode was investigated. The results show that the temperature difference between the inside and the outside of zirconia tube was very small and the Seebeck effect can be ignored after the sensor was dipped into liquid steel for more than 2 s. A special sensor was designed to test the relation between the EMF （electromotive force） of sensor and the thermal equilibrium state of the reference elec- trode. Based on these results, it is suggested that the peak in EMF curve was caused by the change of oxygen potential in reference electrode before the thermal equilibrium was reached. If NiO was added by 2 M- 5 M to the Cr/Cr2O3 reference electrode, the peak in EMF curve could be eliminated.展开更多
In this paper, the λ-central BMO estimates for higher order commuta-tors of Hardy operators on central Morrey space Lq,λ（Rn） are established. In the meanwhile, the corresponding corollary for central BMO estimates...In this paper, the λ-central BMO estimates for higher order commuta-tors of Hardy operators on central Morrey space Lq,λ（Rn） are established. In the meanwhile, the corresponding corollary for central BMO estimates is also obtained.展开更多
A new technique for manufacture of the oxygen sensor used for metallurgical process has been developed.The powder of MgO-PSZ was prepared by coprecipitation.The MgOPSZ tube was prepared by powder injection molding(PIM...A new technique for manufacture of the oxygen sensor used for metallurgical process has been developed.The powder of MgO-PSZ was prepared by coprecipitation.The MgOPSZ tube was prepared by powder injection molding(PIM).The final sintered tube was assembled into oxygen cell,then tested in laboratory and on RH vessel.The results showed that the thermal shock resistance of MgO-PSZ matrix is strong enough for determining the active oxygen concentration in steel melt.The reproducibility of the EMF measurement is very good.The structure of the tube has been analysed by means of SEM and XRD.In addition,the characteristics such as the density and phase ratio in the product were compared with that of Shijiazhuang Maple Wood Sensor Company s product.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 41571087)
文摘The rural settlement is one of important aspects to understand regional human-environment relationships. Zhangjiakou city, located in the poverty belt around Beijing and Tianjin, was used as an example to analyze the evolution of rural settlements during 1985–2010 through the use of statistical and spatial analysis methods. The results demonstrate the following:(1) the area of rural settlements expanded from 665.76 to 928.14 km2 during 1985–2010. Rural settlements in prefecture city of Zhangjiakou were significantly agglomerated in terms of their spatial distribution, which presented an approximately normal distribution over the entire period. Rural settlements were usually distributed within regions where the terrain niche had an elevation of between 900 and 1500 m, and a slope from 5? to 20?;(2) there were significant regional differences in the density and size distribution of rural settlements in Zhangjiakou. The density of rural settlements in 2010 was higher than that in 1985, while there was a clustered distribution of rural settlements in 2010. There was a significant high value cluster in the size distribution, and a local negative correlation between the size and density distribution of rural settlements in Zhangjiakou;(3) rural economic development, investment in agricultural technology, and infrastructure improvement played important roles in the evolution of rural settlements. There were spatial differences in the relationship between the distribution of rural settlements and socio-economic factors in Zhangjiakou. This study provides practical guidance for the achievement of urban and rural integration development and the promotion of a new form of countryside construction.
文摘The thermal equilibrium state of the reference electrode was investigated. The results show that the temperature difference between the inside and the outside of zirconia tube was very small and the Seebeck effect can be ignored after the sensor was dipped into liquid steel for more than 2 s. A special sensor was designed to test the relation between the EMF （electromotive force） of sensor and the thermal equilibrium state of the reference elec- trode. Based on these results, it is suggested that the peak in EMF curve was caused by the change of oxygen potential in reference electrode before the thermal equilibrium was reached. If NiO was added by 2 M- 5 M to the Cr/Cr2O3 reference electrode, the peak in EMF curve could be eliminated.
基金The Pre-research Project(SY201224) of Provincial Key Innovationthe Scientific and Technical Research Project(12531720) of the Education Department of Heilongjiang Province+1 种基金the NSF(A200913) of Heilongjiang Provincethe NSF(11041004,11161042,11071250) of China
文摘In this paper, the λ-central BMO estimates for higher order commuta-tors of Hardy operators on central Morrey space Lq,λ（Rn） are established. In the meanwhile, the corresponding corollary for central BMO estimates is also obtained.
文摘A new technique for manufacture of the oxygen sensor used for metallurgical process has been developed.The powder of MgO-PSZ was prepared by coprecipitation.The MgOPSZ tube was prepared by powder injection molding(PIM).The final sintered tube was assembled into oxygen cell,then tested in laboratory and on RH vessel.The results showed that the thermal shock resistance of MgO-PSZ matrix is strong enough for determining the active oxygen concentration in steel melt.The reproducibility of the EMF measurement is very good.The structure of the tube has been analysed by means of SEM and XRD.In addition,the characteristics such as the density and phase ratio in the product were compared with that of Shijiazhuang Maple Wood Sensor Company s product.
