A review is presented of studies of polymeric membranes by applying positron annihilation lifetime spectroscopy （PALS）. PALS has been used to study subnanometer-sized holes, to determine their size distribution and ...A review is presented of studies of polymeric membranes by applying positron annihilation lifetime spectroscopy （PALS）. PALS has been used to study subnanometer-sized holes, to determine their size distribution and free-volume fractions, and to probe molecular-sized vacancies in glassy polymers. At present, PALS is believed to be a highly effective physical method for the examination of polymeric membranes.展开更多
Energy regeneration during braking is an important technique for hybrid electric vehicle (HEV) to improve their fuel economy and extend their driving range. Due to the effect of regenerative braking torque which is ad...Energy regeneration during braking is an important technique for hybrid electric vehicle (HEV) to improve their fuel economy and extend their driving range. Due to the effect of regenerative braking torque which is added by electric motor, the braking torque distribution between front and rear axles should be changed and the control logic of anti-lock braking system (ABS) ought to be adjusted according to the regenerative braking torque. This paper put forward a braking control strategy for hybrid electric vehicle; the control strategy is implemented with eight DOFs (Degree-of-Freedom) nonlinear vehicle forward simulation model which is built under the environment of Matlab/Simulink. Based on target wheel slip ratio, a fuzzy logic approach was applied to maintain the optimal target slip ratio so that best compromise between hydraulic torque and regenerative torque can be obtained for the vehicle.展开更多
Service and information resources are two kinds of major shared resources in virtual enterprises, where, service resources include third party’s service resources and enterprise’s legacy service resources,and inform...Service and information resources are two kinds of major shared resources in virtual enterprises, where, service resources include third party’s service resources and enterprise’s legacy service resources,and information resources include database resources and file resources. Since service and information resources have distributed, autonomic, remotely bound as well as some other similar characteristics, an implementation mechanism on managing shared resources based on UDDI are presented. XML instances are used to describe resources authorization information, WSDL based special XML instance represents information resource metadata, and these XML instances are referenced by tModel for realizing the purpose of managing shared resources metadata based on UDDI.展开更多
Various process parameters exert different effects in stamping process. In order to study the relationships among the process parameters of box stamping process, including the blank holder force, friction coefficient,...Various process parameters exert different effects in stamping process. In order to study the relationships among the process parameters of box stamping process, including the blank holder force, friction coefficient, depth of drawbead, offset and length of drawbead, the decision tree algorithm C4.5 was performed to generate the decision tree using the result data of the box stamping simulation. The design and improvement methods of the decision tree were presented. Potential and valuable rules were generated by traversing the decision tree, which plays an instructive role on the practical design. The rules show that the correct combination of blank holder force and setting of drawbead are the dominant contribution for controlling the cracking and wrinkling in box stamping process. In order to validate the rules, the stamping process for box was also performed. The experiment results show good agreement with the generated rules.展开更多
On the basis of the three-dimensional elastic inclusion model, the analytic expression of viscoelastic strain field is derived, i.e., the analytic expression of viscoelastic strain at an arbitrary point (x, y, z) in x...On the basis of the three-dimensional elastic inclusion model, the analytic expression of viscoelastic strain field is derived, i.e., the analytic expression of viscoelastic strain at an arbitrary point (x, y, z) in x-axis, y-axis and z-axis produced by three-dimension inclusion in the semi-infinite rheologic medium defined by the standard linear rheologic model, namely the normal strains exx(r, t), eyy(r, t) and ezz(r, t), the shear strains exy(r, t) and eyx(r, t), eyz(r, t) and ezy(r, t), exz(r, t) and ezx(r, t), and the bulk-strain q (r, t). By computing the spatial-temporal variation of bulk strain on the ground produced by a spherical rheologic inclusion in a semi-infinite rheologic medium, we obtained some significant results that the bulk-strain variation with time produced by a hard inclusion has three stages (a, b, g) with different characteristics, which are similar to those of most geodetic deformation curves, but not the case for those by a soft inclusion. It is meaningful that these theoretical results have been applied to explain preliminarily the characteristics of stage variation of spatial-temporal evolution, the pattern and quadrant distribution of earthquake precursors, the changeability, spontaneity and complexity of short-term and imminent-term precursors. It offers a theoretical base to found the physical model of earthquake precursors and a reference to predict physically the earthquakes.展开更多
Promoter-probe vector pSUPV4 is used to clone the promoter of Pseudomonas pseudoalcaligenes directly in E. coli, and the recombinant pPA7, which has the highest kanamycin resistance, is obtained. Sequencing the PA7 fr...Promoter-probe vector pSUPV4 is used to clone the promoter of Pseudomonas pseudoalcaligenes directly in E. coli, and the recombinant pPA7, which has the highest kanamycin resistance, is obtained. Sequencing the PA7 fragment discloses several motifs similar to the conservative domains of prokaryotic promoters, including -10 box, -35 box, parallel SD fragment essential to transcription initiation, and the translation initiation site ATG. Southern blotting of PA7 indicates that the PA7 fragment comes from P. pseudoalcaligenes genome and has probably one copy. The PA7 fragment is subcloned by PCR, and the result shows that the 5’-flanking fragment from 889 to 1120 bp has promoter activity, which can be enhanced by the 0.7Kb fragment at 5’ end. The fragments of pPA7 and pPA7-2 are transferred into pseudomonas pseudoaligenes by electroporation, and the significant higher kanamycin resistance of transformants than that of control indicates that the PA7 fragment has the promoter activity in P. pseudoaligene.展开更多
Google’s algorithm on PageRank is analyzed in details. Some disadvantages of this algorithm is presented, for instance, preferring old pages, ignoring special sites and inaccurate judge of hyperlinks pointed out from...Google’s algorithm on PageRank is analyzed in details. Some disadvantages of this algorithm is presented, for instance, preferring old pages, ignoring special sites and inaccurate judge of hyperlinks pointed out from one page. Furthermore, author’s improved algorithm is described. Experiments show that the author’s consideration on evaluating the importance of pages can make an improvement over the original algorithm. Based on this improved algorithm a topic specific searching system have been developed.展开更多
2021年11月4日,日内瓦高级钟表大赏(后称GPHG)落下帷幕,本届GPHG上,共有84枚参赛作品向14个奖项发起挑战,今年大会还设有金指针奖(Aiguille d’Or Grand Prix)、最佳机械创新奖(Innovation)、无畏奖(Audacity)和钟表启示奖(Horological ...2021年11月4日,日内瓦高级钟表大赏(后称GPHG)落下帷幕,本届GPHG上,共有84枚参赛作品向14个奖项发起挑战,今年大会还设有金指针奖(Aiguille d’Or Grand Prix)、最佳机械创新奖(Innovation)、无畏奖(Audacity)和钟表启示奖(Horological Revelation),与钟表有关的奖项共计18个,本期精选腕表献给想要买表的读者。展开更多
基金The project supported by the Hundred-Persons Plan Foundation of Chinese Academy of Sciences in 2003
文摘A review is presented of studies of polymeric membranes by applying positron annihilation lifetime spectroscopy （PALS）. PALS has been used to study subnanometer-sized holes, to determine their size distribution and free-volume fractions, and to probe molecular-sized vacancies in glassy polymers. At present, PALS is believed to be a highly effective physical method for the examination of polymeric membranes.
基金863 National Project EQ7200HEV hybridelectric vehicle (2001AA501200,2003AA501200)
文摘Energy regeneration during braking is an important technique for hybrid electric vehicle (HEV) to improve their fuel economy and extend their driving range. Due to the effect of regenerative braking torque which is added by electric motor, the braking torque distribution between front and rear axles should be changed and the control logic of anti-lock braking system (ABS) ought to be adjusted according to the regenerative braking torque. This paper put forward a braking control strategy for hybrid electric vehicle; the control strategy is implemented with eight DOFs (Degree-of-Freedom) nonlinear vehicle forward simulation model which is built under the environment of Matlab/Simulink. Based on target wheel slip ratio, a fuzzy logic approach was applied to maintain the optimal target slip ratio so that best compromise between hydraulic torque and regenerative torque can be obtained for the vehicle.
文摘Service and information resources are two kinds of major shared resources in virtual enterprises, where, service resources include third party’s service resources and enterprise’s legacy service resources,and information resources include database resources and file resources. Since service and information resources have distributed, autonomic, remotely bound as well as some other similar characteristics, an implementation mechanism on managing shared resources based on UDDI are presented. XML instances are used to describe resources authorization information, WSDL based special XML instance represents information resource metadata, and these XML instances are referenced by tModel for realizing the purpose of managing shared resources metadata based on UDDI.
文摘Various process parameters exert different effects in stamping process. In order to study the relationships among the process parameters of box stamping process, including the blank holder force, friction coefficient, depth of drawbead, offset and length of drawbead, the decision tree algorithm C4.5 was performed to generate the decision tree using the result data of the box stamping simulation. The design and improvement methods of the decision tree were presented. Potential and valuable rules were generated by traversing the decision tree, which plays an instructive role on the practical design. The rules show that the correct combination of blank holder force and setting of drawbead are the dominant contribution for controlling the cracking and wrinkling in box stamping process. In order to validate the rules, the stamping process for box was also performed. The experiment results show good agreement with the generated rules.
基金Chinese Joint Seismological Science Foundation (101105).
文摘On the basis of the three-dimensional elastic inclusion model, the analytic expression of viscoelastic strain field is derived, i.e., the analytic expression of viscoelastic strain at an arbitrary point (x, y, z) in x-axis, y-axis and z-axis produced by three-dimension inclusion in the semi-infinite rheologic medium defined by the standard linear rheologic model, namely the normal strains exx(r, t), eyy(r, t) and ezz(r, t), the shear strains exy(r, t) and eyx(r, t), eyz(r, t) and ezy(r, t), exz(r, t) and ezx(r, t), and the bulk-strain q (r, t). By computing the spatial-temporal variation of bulk strain on the ground produced by a spherical rheologic inclusion in a semi-infinite rheologic medium, we obtained some significant results that the bulk-strain variation with time produced by a hard inclusion has three stages (a, b, g) with different characteristics, which are similar to those of most geodetic deformation curves, but not the case for those by a soft inclusion. It is meaningful that these theoretical results have been applied to explain preliminarily the characteristics of stage variation of spatial-temporal evolution, the pattern and quadrant distribution of earthquake precursors, the changeability, spontaneity and complexity of short-term and imminent-term precursors. It offers a theoretical base to found the physical model of earthquake precursors and a reference to predict physically the earthquakes.
文摘Promoter-probe vector pSUPV4 is used to clone the promoter of Pseudomonas pseudoalcaligenes directly in E. coli, and the recombinant pPA7, which has the highest kanamycin resistance, is obtained. Sequencing the PA7 fragment discloses several motifs similar to the conservative domains of prokaryotic promoters, including -10 box, -35 box, parallel SD fragment essential to transcription initiation, and the translation initiation site ATG. Southern blotting of PA7 indicates that the PA7 fragment comes from P. pseudoalcaligenes genome and has probably one copy. The PA7 fragment is subcloned by PCR, and the result shows that the 5’-flanking fragment from 889 to 1120 bp has promoter activity, which can be enhanced by the 0.7Kb fragment at 5’ end. The fragments of pPA7 and pPA7-2 are transferred into pseudomonas pseudoaligenes by electroporation, and the significant higher kanamycin resistance of transformants than that of control indicates that the PA7 fragment has the promoter activity in P. pseudoaligene.
文摘Google’s algorithm on PageRank is analyzed in details. Some disadvantages of this algorithm is presented, for instance, preferring old pages, ignoring special sites and inaccurate judge of hyperlinks pointed out from one page. Furthermore, author’s improved algorithm is described. Experiments show that the author’s consideration on evaluating the importance of pages can make an improvement over the original algorithm. Based on this improved algorithm a topic specific searching system have been developed.
文摘2021年11月4日,日内瓦高级钟表大赏(后称GPHG)落下帷幕,本届GPHG上,共有84枚参赛作品向14个奖项发起挑战,今年大会还设有金指针奖(Aiguille d’Or Grand Prix)、最佳机械创新奖(Innovation)、无畏奖(Audacity)和钟表启示奖(Horological Revelation),与钟表有关的奖项共计18个,本期精选腕表献给想要买表的读者。
