Classification of plume and spatter images was studied to evaluate the welding stability. A high-speed camera was used to capture the instantaneous images of plume and spatters during high power disk laser welding. Ch...Classification of plume and spatter images was studied to evaluate the welding stability. A high-speed camera was used to capture the instantaneous images of plume and spatters during high power disk laser welding. Characteristic parameters such as the area and number of spatters, the average grayscale of a spatter image, the entropy of a spatter grayscale image, the coordinate ratio of the plume centroid and the welding point, the polar coordinates of the plume centroid were defined and extracted. Karhunen-Loeve transform method was used to change the seven characteristics into three primary characteristics to reduce the dimensions. Also, K-nearest neighbor method was used to classify the plume and spatter images into two categories such as good and poor welding quality. The results show that plume and spatter have a close relationship with the welding stability, and two categories could be recognized effectively using K-nearest neighbor method based on Karhunen-Loeve transform.展开更多
The genus Barbodes Bleeker is a catchall group.The species assigned to this genus in China actually belong to at least four distinct genera.After comparing all the Barbodes fishes included in this research to the syst...The genus Barbodes Bleeker is a catchall group.The species assigned to this genus in China actually belong to at least four distinct genera.After comparing all the Barbodes fishes included in this research to the system used by Rainboth,reassign Barbodes fishes in China as following:①B.baoshanensis,B.benasi and B.heterostomus are assigned to genus Neolissochilus;②B.parvus are assigned as Discherodontus parvus;③B.pierrei in Yunnan is conspecific with B.vernayi and B.vernayi should be assigned to the genus Hypsibarbus as Hypsibarbus vernayi;④the remaining Barbodes fishes,B.fuxianhuensis,B.chonglingchungi,B.margarianus,B.huangchuchieni,B.cogginii (=B.daliensis),B.rhomboides,B.carinatus,B.opisthopterus and B.exiguus are assigned to genus Poropuntius.展开更多
Particle image velocimetry technique was used to analyze the trailing vortices and elucidate their rela-tionship with turbulence properties in a stirred tank of 0.48 m diameter,agitated by four different disc turbines...Particle image velocimetry technique was used to analyze the trailing vortices and elucidate their rela-tionship with turbulence properties in a stirred tank of 0.48 m diameter,agitated by four different disc turbines,in-cluding Rushton turbine,concaved blade disk turbine,half elliptical blade disk turbine,and parabolic blade disk turbine.Phase-averaged and phase-resolved flow fields near the impeller blades were measured and the structure of trailing vortices was studied in detail.The location,size and strength of vortices were determined by the simplified λ2-criterion and the results showed that the blade shape had great effect on the trailing vortex characteristics.The larger curvature resulted in longer residence time of the vortex at the impeller tip,bigger distance between the upper and lower vortices and longer vortex life,also leads to smaller and stronger vortices.In addition,the turbulent ki-netic energy and turbulent energy dissipation in the discharge flow were determined and discussed.High turbulent kinetic energy and turbulent energy dissipation regions were located between the upper and lower vortices and moved along with them.Although restricted to single phase flow,the presented results are essential for reliable de-sign and scale-up of stirred tank with disc turbines.展开更多
Objective To evaluate the different influences of anterior and posterior correction and fusion approaches upon disc wedging in adolescent idiopathic thoracolumbar/lumbar scoliosis.Methods The retrospective study was c...Objective To evaluate the different influences of anterior and posterior correction and fusion approaches upon disc wedging in adolescent idiopathic thoracolumbar/lumbar scoliosis.Methods The retrospective study was conducted with the medical records and radiographs of adolescent idiopathic thoracolumbar/lumbar scoliosis patients that underwent anterior(group A) or posterior(group B) correction and fusion surgery from December 1998 to May 2008.The correction of the main curve and changes of the disc wedging were analyzed.Results Fifty-three patients were included,26 in group A and 27 in group B.The mean coronal Cobb angles of the main curve in group A and group B were significantly corrected after surgery(P<0.05),with an average correction rate of 75.2% and 88.2%,respectively.Upon final follow-up,the coronal Cobb angles of the two groups were 18.9°±11.1° and 7.7°±5.6°,respectively,with an average correction loss of 6.8°±6.5° and 2.7°±3.3°,respectively.The coronal Cobb angle after operation and at final follow-up,and the correction rate were significantly better in group B than those in group A(P<0.05),while the coronal Cobb angle loss in group A was greater than that in group B(P<0.05).The disc wedging before operation,after operation,and at final follow-up were 3.2°±3.0°,5.7°±3.0°,and 8.6°±4.4° in group A,and 2.4°±3.2°,3.3°±3.4°,and 3.7°±3.6° in group B,respectively.Postoperative disc wedging was significantly larger compared with preoperative measurements in group A(P<0.05),but not in group B(P>0.05).The difference between disc wedging at final follow-up and that after surgery was significant in group A(P<0.05),but not in group B(P>0.05).Between the two groups,group A had larger disc angles after operation and at final follow-up(P<0.05),and a greater loss of disc angle(P<0.05).Conclusion For adolescent idiopathic thoracolumbar/lumbar scoliosis,posterior approach using all pedicle screws might produce a better result in terms of disc wedging compared with anterior approach.展开更多
Objective To investigate the main proteinases responsible for CD16b shedding under different stimulators. Methods HEK293 cell line stably expressing CD16b was constructed by lentivirus system. The cell line was then ...Objective To investigate the main proteinases responsible for CD16b shedding under different stimulators. Methods HEK293 cell line stably expressing CD16b was constructed by lentivirus system. The cell line was then overexpressed with a disintegrin and metalloproteinase 10 (ADAM10) or ADAM17, sup- pressed with short hairpin RNA of ADAM10 or ADAM I 7, and reconstituted with ADAM 10 or ADAM17, respectively. After each treatment, the cell line was stimulated with ionomycin or phorbol 12-myristate- 13-acetate (PMA) for 12 hours. The soluble CD 16b released from cell membrane was detected by immuno- precipition and immunoblot. Quantitation was then implemented to compare the amount of soluble CD 16b in cell supernatant after stimulation. Results HEK293 cell line stably expressing CD16b was successfully established. When CDI6b ex- pressing cell line was overexpressed with ADAM 10, shedding of CD 16b was increased after stimulation with ionomycin but not PMA; when the cell line overexpressed with ADAM I7, shedding of CDI6b was increased after stimulation with PMA but not ionomycin. Similarly, when ADAM10 was suppressed by short hairpin RNA, CD 16b shedding was decreased after stimulation with ionomycin; when ADAM 17 was suppressed by short hairpin RNA, CD16b shedding was decreased after stimulation with PMA. The shedding of CD16b was increased again when CD16b expressing cell line was reconstituted with ADAM10 and stimulated by ionomycin or reconstituted with ADAM 17 and stimulated by PMA. Conclusions Both ADAM10 and ADAM17 could shed CD16b, but they possess differed prefer- ences. ADAM10 is the main sheddase under stimulation of ionomycin, while ADAM17 is the main sheddase under stimulation of PMA.展开更多
The effects of the mixing of wave transport flux residual(Bvl) on the upper ocean is studied through carrying out the control run(CR) and a series of sensitive runs(SR) with ROMS model.In this study,the important role...The effects of the mixing of wave transport flux residual(Bvl) on the upper ocean is studied through carrying out the control run(CR) and a series of sensitive runs(SR) with ROMS model.In this study,the important role of Bvl is revealed by comparing the ocean temperature,statistical analysis of errors and evaluating the mixed layer depth.It is shown that the overestimated SST is improved effectively when the wave-induced mixing is incorporated to the vertical mixing scheme.As can be seen from the vertical structure of temperature 28℃ isotherm changes from 20 min CR to 35 m in SR3,which is more close to the observation.Statistic analysis shows that the root-mean-square errors of the temperature in 10 m are reduced and the correlation between model results and observation data are increased after considering the effect of Bvl.The numerical results of the ocean temperature show improvement in summer and in tropical zones in winter,especially in the strong current regions in summer.In August the mixed layer depth(MLD) which is defined as the depth that the temperature has changed 0.5℃ from the reference depth of 10 m is further analyzed.The simulation results have a close relationship with undetermined coefficient of Bvl,sensitivity studies show that a coefficient about 0.1 is reasonable value in the model.展开更多
Liquid argon flow along a nanochannel is studied using molecular dynamics (MD) simulation in this work.Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) is used as the MD simulator.The effects of redu...Liquid argon flow along a nanochannel is studied using molecular dynamics (MD) simulation in this work.Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) is used as the MD simulator.The effects of reduced forces at 0.5,1.0 and 2.0 on argon flow on system energy in the form of system potential energy,pressure and velocity profile are described.Output in the form of three-dimensional visualization of the system at steady-state condition using Visual Molecular Dynamics (VMD) is provided to describe the dynamics of the argon atoms.The equilibrium state is reached after 16000 time steps.The effects on system energy,pressure and velocity profile due to reduced force of 2.0 (F2) are clearly distinguishable from the other two lower forces where sufficiently high net force along the direction of the nanochannel for F2 renders the attractive and repulsive forces between the argon atoms virtually non-existent.A reduced force of 0.5 (F0.5) provides liquid argon flow that approaches Poiseuille (laminar) flow as clearly shown by the n-shaped average velocity profile.The extension of the present MD model to a more practical application affords scientists and engineers a good option for simulation of other nanofluidic dynamics processes.展开更多
The chiral separation of phenylsuccinic acid(PSA)was studied by reversed phase high-performance liquid chromatography(RP-HPLC)with cyclodextrins(CDs)as chiral mobile phase additives.The effects of types of CDs,concent...The chiral separation of phenylsuccinic acid(PSA)was studied by reversed phase high-performance liquid chromatography(RP-HPLC)with cyclodextrins(CDs)as chiral mobile phase additives.The effects of types of CDs,concentration of hydroxypropyl-β-cyclodextrin(HP-β-CD),percentage of organic modifier,pH value and column temperature on enantioselective separation were investigated.The quantification property of the developed RP-HPLC method was examined.The chiral recognition mechanism of PSA was also discussed.The results show that a baseline separation of PSA enantiomers is achieved on a Lichrospher C18 column(4.6 mm(inner diameter)×250 mm,5μm)with HP-β-CD as chiral mobile phase additive.The capacity factors of R-PSA and S-PSA are 3.94 and 4.80,respectively.The separation factor and resolution are respectively 1.22 and 8.03.The mobile phase is a mixture of acetonitrile and deionized water(20-80,volume ratio)containing 10 mmol/L HP-β-CD and 0.05% trifluoroacetic acid(pH 2.5,adjusted with triethylamine)with a flow rate of 1.0 mL/min.The ultraviolet(UV)detector is set at 254 nm.The likely roles are inclusion interaction,induction and hydrogen bonding between HP-β-CD and PSA enantiomers.展开更多
基金Project (51175095) supported by the National Natural Science Foundation of ChinaProjects (10251009001000001,9151009001000020) supported by the Natural Science Foundation of Guangdong Province,ChinaProject (20104420110001) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘Classification of plume and spatter images was studied to evaluate the welding stability. A high-speed camera was used to capture the instantaneous images of plume and spatters during high power disk laser welding. Characteristic parameters such as the area and number of spatters, the average grayscale of a spatter image, the entropy of a spatter grayscale image, the coordinate ratio of the plume centroid and the welding point, the polar coordinates of the plume centroid were defined and extracted. Karhunen-Loeve transform method was used to change the seven characteristics into three primary characteristics to reduce the dimensions. Also, K-nearest neighbor method was used to classify the plume and spatter images into two categories such as good and poor welding quality. The results show that plume and spatter have a close relationship with the welding stability, and two categories could be recognized effectively using K-nearest neighbor method based on Karhunen-Loeve transform.
文摘The genus Barbodes Bleeker is a catchall group.The species assigned to this genus in China actually belong to at least four distinct genera.After comparing all the Barbodes fishes included in this research to the system used by Rainboth,reassign Barbodes fishes in China as following:①B.baoshanensis,B.benasi and B.heterostomus are assigned to genus Neolissochilus;②B.parvus are assigned as Discherodontus parvus;③B.pierrei in Yunnan is conspecific with B.vernayi and B.vernayi should be assigned to the genus Hypsibarbus as Hypsibarbus vernayi;④the remaining Barbodes fishes,B.fuxianhuensis,B.chonglingchungi,B.margarianus,B.huangchuchieni,B.cogginii (=B.daliensis),B.rhomboides,B.carinatus,B.opisthopterus and B.exiguus are assigned to genus Poropuntius.
基金Supported by the National Natural Science Foundation of China(20776008 20821004 20990224) the National Basic Research Program of China(2007CB714300)
文摘Particle image velocimetry technique was used to analyze the trailing vortices and elucidate their rela-tionship with turbulence properties in a stirred tank of 0.48 m diameter,agitated by four different disc turbines,in-cluding Rushton turbine,concaved blade disk turbine,half elliptical blade disk turbine,and parabolic blade disk turbine.Phase-averaged and phase-resolved flow fields near the impeller blades were measured and the structure of trailing vortices was studied in detail.The location,size and strength of vortices were determined by the simplified λ2-criterion and the results showed that the blade shape had great effect on the trailing vortex characteristics.The larger curvature resulted in longer residence time of the vortex at the impeller tip,bigger distance between the upper and lower vortices and longer vortex life,also leads to smaller and stronger vortices.In addition,the turbulent ki-netic energy and turbulent energy dissipation in the discharge flow were determined and discussed.High turbulent kinetic energy and turbulent energy dissipation regions were located between the upper and lower vortices and moved along with them.Although restricted to single phase flow,the presented results are essential for reliable de-sign and scale-up of stirred tank with disc turbines.
文摘Objective To evaluate the different influences of anterior and posterior correction and fusion approaches upon disc wedging in adolescent idiopathic thoracolumbar/lumbar scoliosis.Methods The retrospective study was conducted with the medical records and radiographs of adolescent idiopathic thoracolumbar/lumbar scoliosis patients that underwent anterior(group A) or posterior(group B) correction and fusion surgery from December 1998 to May 2008.The correction of the main curve and changes of the disc wedging were analyzed.Results Fifty-three patients were included,26 in group A and 27 in group B.The mean coronal Cobb angles of the main curve in group A and group B were significantly corrected after surgery(P<0.05),with an average correction rate of 75.2% and 88.2%,respectively.Upon final follow-up,the coronal Cobb angles of the two groups were 18.9°±11.1° and 7.7°±5.6°,respectively,with an average correction loss of 6.8°±6.5° and 2.7°±3.3°,respectively.The coronal Cobb angle after operation and at final follow-up,and the correction rate were significantly better in group B than those in group A(P<0.05),while the coronal Cobb angle loss in group A was greater than that in group B(P<0.05).The disc wedging before operation,after operation,and at final follow-up were 3.2°±3.0°,5.7°±3.0°,and 8.6°±4.4° in group A,and 2.4°±3.2°,3.3°±3.4°,and 3.7°±3.6° in group B,respectively.Postoperative disc wedging was significantly larger compared with preoperative measurements in group A(P<0.05),but not in group B(P>0.05).The difference between disc wedging at final follow-up and that after surgery was significant in group A(P<0.05),but not in group B(P>0.05).Between the two groups,group A had larger disc angles after operation and at final follow-up(P<0.05),and a greater loss of disc angle(P<0.05).Conclusion For adolescent idiopathic thoracolumbar/lumbar scoliosis,posterior approach using all pedicle screws might produce a better result in terms of disc wedging compared with anterior approach.
基金Supported by the National Natural Science Foundation of China (30872287)
文摘Objective To investigate the main proteinases responsible for CD16b shedding under different stimulators. Methods HEK293 cell line stably expressing CD16b was constructed by lentivirus system. The cell line was then overexpressed with a disintegrin and metalloproteinase 10 (ADAM10) or ADAM17, sup- pressed with short hairpin RNA of ADAM10 or ADAM I 7, and reconstituted with ADAM 10 or ADAM17, respectively. After each treatment, the cell line was stimulated with ionomycin or phorbol 12-myristate- 13-acetate (PMA) for 12 hours. The soluble CD 16b released from cell membrane was detected by immuno- precipition and immunoblot. Quantitation was then implemented to compare the amount of soluble CD 16b in cell supernatant after stimulation. Results HEK293 cell line stably expressing CD16b was successfully established. When CDI6b ex- pressing cell line was overexpressed with ADAM 10, shedding of CD 16b was increased after stimulation with ionomycin but not PMA; when the cell line overexpressed with ADAM I7, shedding of CDI6b was increased after stimulation with PMA but not ionomycin. Similarly, when ADAM10 was suppressed by short hairpin RNA, CD 16b shedding was decreased after stimulation with ionomycin; when ADAM 17 was suppressed by short hairpin RNA, CD16b shedding was decreased after stimulation with PMA. The shedding of CD16b was increased again when CD16b expressing cell line was reconstituted with ADAM10 and stimulated by ionomycin or reconstituted with ADAM 17 and stimulated by PMA. Conclusions Both ADAM10 and ADAM17 could shed CD16b, but they possess differed prefer- ences. ADAM10 is the main sheddase under stimulation of ionomycin, while ADAM17 is the main sheddase under stimulation of PMA.
基金supported by the National Key Basic Research and Development Program(2010CB950404)the National High Technology Research and Development Program(2013AA09A506)
文摘The effects of the mixing of wave transport flux residual(Bvl) on the upper ocean is studied through carrying out the control run(CR) and a series of sensitive runs(SR) with ROMS model.In this study,the important role of Bvl is revealed by comparing the ocean temperature,statistical analysis of errors and evaluating the mixed layer depth.It is shown that the overestimated SST is improved effectively when the wave-induced mixing is incorporated to the vertical mixing scheme.As can be seen from the vertical structure of temperature 28℃ isotherm changes from 20 min CR to 35 m in SR3,which is more close to the observation.Statistic analysis shows that the root-mean-square errors of the temperature in 10 m are reduced and the correlation between model results and observation data are increased after considering the effect of Bvl.The numerical results of the ocean temperature show improvement in summer and in tropical zones in winter,especially in the strong current regions in summer.In August the mixed layer depth(MLD) which is defined as the depth that the temperature has changed 0.5℃ from the reference depth of 10 m is further analyzed.The simulation results have a close relationship with undetermined coefficient of Bvl,sensitivity studies show that a coefficient about 0.1 is reasonable value in the model.
基金Supported by the Academy of Sciences,Malaysia and Ministry of Science and Technology & Innovation
文摘Liquid argon flow along a nanochannel is studied using molecular dynamics (MD) simulation in this work.Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) is used as the MD simulator.The effects of reduced forces at 0.5,1.0 and 2.0 on argon flow on system energy in the form of system potential energy,pressure and velocity profile are described.Output in the form of three-dimensional visualization of the system at steady-state condition using Visual Molecular Dynamics (VMD) is provided to describe the dynamics of the argon atoms.The equilibrium state is reached after 16000 time steps.The effects on system energy,pressure and velocity profile due to reduced force of 2.0 (F2) are clearly distinguishable from the other two lower forces where sufficiently high net force along the direction of the nanochannel for F2 renders the attractive and repulsive forces between the argon atoms virtually non-existent.A reduced force of 0.5 (F0.5) provides liquid argon flow that approaches Poiseuille (laminar) flow as clearly shown by the n-shaped average velocity profile.The extension of the present MD model to a more practical application affords scientists and engineers a good option for simulation of other nanofluidic dynamics processes.
基金Project(20776038)supported by the National Natural Science Foundation of China
文摘The chiral separation of phenylsuccinic acid(PSA)was studied by reversed phase high-performance liquid chromatography(RP-HPLC)with cyclodextrins(CDs)as chiral mobile phase additives.The effects of types of CDs,concentration of hydroxypropyl-β-cyclodextrin(HP-β-CD),percentage of organic modifier,pH value and column temperature on enantioselective separation were investigated.The quantification property of the developed RP-HPLC method was examined.The chiral recognition mechanism of PSA was also discussed.The results show that a baseline separation of PSA enantiomers is achieved on a Lichrospher C18 column(4.6 mm(inner diameter)×250 mm,5μm)with HP-β-CD as chiral mobile phase additive.The capacity factors of R-PSA and S-PSA are 3.94 and 4.80,respectively.The separation factor and resolution are respectively 1.22 and 8.03.The mobile phase is a mixture of acetonitrile and deionized water(20-80,volume ratio)containing 10 mmol/L HP-β-CD and 0.05% trifluoroacetic acid(pH 2.5,adjusted with triethylamine)with a flow rate of 1.0 mL/min.The ultraviolet(UV)detector is set at 254 nm.The likely roles are inclusion interaction,induction and hydrogen bonding between HP-β-CD and PSA enantiomers.