China is a country with a long history of agricultural development,the tr adition of bureaucratic administra-tion and economic management system s for the social development.In its t ransition from traditional society...China is a country with a long history of agricultural development,the tr adition of bureaucratic administra-tion and economic management system s for the social development.In its t ransition from traditional society to modern soci-ety during the past 50years,the rela tions between rural areas and urban a reas have been kept abnormal if considered from the point of view of the modernized co untries.Today,China still has its more than 70percent of population,bu t limited capital,lower technology and underdeveloped culture,in the rural areas.This unbalance forms not only the o bstacles to China’s modernization of social development,but also the barriers to th e society,economy and environment sustainable devel-opment.This paper focuses on the dis cussion about the coordinate develo pment of the relations between rural and urban in the past 50years,and the authors hold that only has the abnormal relation between the two areas been corrected,could China’s future development of natio nal economy be successful.展开更多
This article obtains some theoretical results on the number of clear two-factor interaction components and weak minimum aberration in an sm-pIVdesign, by considering the number of not clear two-factor interaction comp...This article obtains some theoretical results on the number of clear two-factor interaction components and weak minimum aberration in an sm-pIVdesign, by considering the number of not clear two-factor interaction components of the design.展开更多
We present a systematic investigation of the impact of changing the geometry structure of the SPC/E water model by performing a series of molecular dynamic simulations at 1 bar （1 bar = 105 Pa） and 298.15 K. The geo...We present a systematic investigation of the impact of changing the geometry structure of the SPC/E water model by performing a series of molecular dynamic simulations at 1 bar （1 bar = 105 Pa） and 298.15 K. The geometric modification includes altering the H-O-H angle range from 90° to 115° and modifying the O-H length range from 0.90 A to 1.10 A in the SPC/E model. The former is achieved by keeping the dipole moment constant by modifying the O-H length, while in the latter only the O-H length is changed. With the larger bond length and angle, we find that the liquid shows a strong quadrupole interaction and high tetrahedral structure order parameter, resulting in the enhancement of the network structure of the liquid. When the bond length or angle is reduced, the hydrogen bond lifetime and self-diffusion constant decrease due to the weakening of the intermolecular interaction. We find that modifying the water molecular bond length leading to the variation of the intermolecular interaction strength is more intensive than changing the bond angle. Through calculating the average reduced density gradient and thermal fluctuation index, it is found that the scope of vdW interaction with neighbouring water molecules is inversely proportional to the change of the bond length and angle. The effect is mainly due to a significant change of the hydrogen bond network. To study the effect of water models as a solvent whose geometry has been modified, the solutions of ions in different solvent environments are examined by introducing NaCI. During the dissolving process, NaCI ions are ideally dissolved in SPC/E water and bond with natural water more easily than with other solvent models.展开更多
Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated in...Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated into poly（ethylene terephthalate） （PET）/random terpolymer elastomer （ST2000） blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blend- ing, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated me- chanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn＇t be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impact- fractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.展开更多
文摘China is a country with a long history of agricultural development,the tr adition of bureaucratic administra-tion and economic management system s for the social development.In its t ransition from traditional society to modern soci-ety during the past 50years,the rela tions between rural areas and urban a reas have been kept abnormal if considered from the point of view of the modernized co untries.Today,China still has its more than 70percent of population,bu t limited capital,lower technology and underdeveloped culture,in the rural areas.This unbalance forms not only the o bstacles to China’s modernization of social development,but also the barriers to th e society,economy and environment sustainable devel-opment.This paper focuses on the dis cussion about the coordinate develo pment of the relations between rural and urban in the past 50years,and the authors hold that only has the abnormal relation between the two areas been corrected,could China’s future development of natio nal economy be successful.
基金supported by the China Postdoctoral Science Foundation (20060390169)the Philosophy and Social Science Foundation of China (07CTJ002)+1 种基金the National Natural Science Foundation of China (10671099)Program for New Century Excellent Talents in University(NCET-08-0909)
文摘This article obtains some theoretical results on the number of clear two-factor interaction components and weak minimum aberration in an sm-pIVdesign, by considering the number of not clear two-factor interaction components of the design.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11635003,11025524,and 11161130520)the National Basic Research Program of China(Grant No.2010CB832903)the European Commission’s 7th Framework Programme(Fp7-PEOPLE-2010-IRSES)(Grant Agreement Project No.269131)
文摘We present a systematic investigation of the impact of changing the geometry structure of the SPC/E water model by performing a series of molecular dynamic simulations at 1 bar （1 bar = 105 Pa） and 298.15 K. The geometric modification includes altering the H-O-H angle range from 90° to 115° and modifying the O-H length range from 0.90 A to 1.10 A in the SPC/E model. The former is achieved by keeping the dipole moment constant by modifying the O-H length, while in the latter only the O-H length is changed. With the larger bond length and angle, we find that the liquid shows a strong quadrupole interaction and high tetrahedral structure order parameter, resulting in the enhancement of the network structure of the liquid. When the bond length or angle is reduced, the hydrogen bond lifetime and self-diffusion constant decrease due to the weakening of the intermolecular interaction. We find that modifying the water molecular bond length leading to the variation of the intermolecular interaction strength is more intensive than changing the bond angle. Through calculating the average reduced density gradient and thermal fluctuation index, it is found that the scope of vdW interaction with neighbouring water molecules is inversely proportional to the change of the bond length and angle. The effect is mainly due to a significant change of the hydrogen bond network. To study the effect of water models as a solvent whose geometry has been modified, the solutions of ions in different solvent environments are examined by introducing NaCI. During the dissolving process, NaCI ions are ideally dissolved in SPC/E water and bond with natural water more easily than with other solvent models.
文摘Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated into poly（ethylene terephthalate） （PET）/random terpolymer elastomer （ST2000） blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blend- ing, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated me- chanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn＇t be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impact- fractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.
