Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaO...Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaOH–CO_(2) chemical absorption method, the aevalues of three RPB reactors with different rotor sizes were measured under different operation conditions. The results showed that the high gravity factor and liquid flow rate were major affecting factors, while the gas flow rate exhibited minor influence.The radius of packing is the dominant equipment factor to affect aevalue. The results indicated that the contact area depends on the dispersion of the liquid phase, thus the centrifugal force of rotating packed bed greatly influenced the aevalue. Moreover, the measured ae/ap(effective specific mass transfer area/specific surface area of packing) values were fitted with dimensionless correlation formulas. The unified correlation formula with dimensionless bed size parameter can well predict the experimental data and the prediction errors were within 15%.展开更多
Micron/nano scale topographic modification has been a significant focus of interest in current titanium(Ti)surface design.However,the influence of micron/nano structured surface on cell or bacterium behavior on the Ti...Micron/nano scale topographic modification has been a significant focus of interest in current titanium(Ti)surface design.However,the influence of micron/nano structured surface on cell or bacterium behavior on the Ti implant has rarely been systematically evaluated.Moreover,except for popular microgrooves,little work has been carried out on the reaction of cells to the bionic structure.In this study,several micro-pillars mimicking cell morphology were prepared on Ti surfaces by lithography and contact printing(ICP)method,and they were further decorated with nanotube arrays by anodization technology.These surface modifications remarkablly increased the surface roughness of pristine Ti surface from 91.17 nm±5.57 nm to be more than 1000 nm,and reduced their water contact angles from 68.3°±0.7°to be 16.9°±2.4°.Then,the effects of these hierarchical micron/nano scale patterns on the behaviors of MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis were studied,aiming to evaluate their performance in osseointegration,gingival epithelial sealing and antibacterial ability.Through an innovative scoring strategy,our findings showed that square micro-pillars with 6μm width and 2μm height combined with 85 nm diameter nanotubes was suitable for implant neck design,while square micro-pillars with 3μm width and 3.6μm height combined with 55 nm diameter nanotubes was the best for implant body design.Our study reveals the synergistic effect of the hierarchical micron/nano scale patterns on MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis functions.It provides insight into the design of biomedical implant surfaces.展开更多
A single particle aerosol mass spectrometer was deployed to measure the changes of single particle species and sizes during March 2015 in Weizhou Island of the Beibu Gulf, Guangxi province, South China. In this campai...A single particle aerosol mass spectrometer was deployed to measure the changes of single particle species and sizes during March 2015 in Weizhou Island of the Beibu Gulf, Guangxi province, South China. In this campaign, a total of 3,100,597 particles were sized, and 25.8%particles with both positive and negative mass spectrum were collected and 24.8%characterized in combination with the ART-2 a neural network algorithm. The distribution of sized particles was mainly in from 520 to 600 nm, and the diameters ranging from 340 to1000 nm accounted for above 90%. Eight types of particles were classified: Elemental Carbon containing(EC), Organic Carbon containing(OC), EC and OC combined containing particles,Na containing particles, K containing particles(K), Levoglucosan containing particles,mineral containing particles, and Heavy Metal containing particles(HM). EC, OC and K were the major containing particles, which accounted for 84.3% in the eight types particles. The relative ratio and size distribution of the three types were EC(48.1%, 620 nm), OC(12.7%,440 nm), and K(23.5%, 600 nm), respectively. The three types of particles were a bit increasing ratios compared with those in clean periods during haze pollution periods.Combined with the back-trajectory results from the Hysplit-4 model and local pollution sources revealed that the ambient air quality on the Weizhou Island may be influenced by biomass burning in the Indochina Peninsula(biomass burning in the Indochina Peninsula)from the transportation on higher level atmospheric layer and by mainland of south China located northeast of Weizhou Island on the ground.展开更多
基金the support from the National Natural Science Foundation of China (22008157,21978178)。
文摘Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaOH–CO_(2) chemical absorption method, the aevalues of three RPB reactors with different rotor sizes were measured under different operation conditions. The results showed that the high gravity factor and liquid flow rate were major affecting factors, while the gas flow rate exhibited minor influence.The radius of packing is the dominant equipment factor to affect aevalue. The results indicated that the contact area depends on the dispersion of the liquid phase, thus the centrifugal force of rotating packed bed greatly influenced the aevalue. Moreover, the measured ae/ap(effective specific mass transfer area/specific surface area of packing) values were fitted with dimensionless correlation formulas. The unified correlation formula with dimensionless bed size parameter can well predict the experimental data and the prediction errors were within 15%.
基金supported by the National Natural Science Foundation of China[grant number 42205121]the Natural Science Foundation of Guangxi Province[grant number 2018JJA150164]the Guangxi Engineering Technology Research Center of Source Analysis and Forecasting of Air Pollution.
基金This work was funded by the National Natural Science Foundation of China(No.81801855)Young Elite Scientist Sponsorship Program by CSA(No.2018QNRC001)+1 种基金Fundamental Research Funds for the Central Universities,Chengguan District Science and Technology Project(No.2018-7-6)Lanzhou University Hospital of Stomatology Research Support Fund.
文摘Micron/nano scale topographic modification has been a significant focus of interest in current titanium(Ti)surface design.However,the influence of micron/nano structured surface on cell or bacterium behavior on the Ti implant has rarely been systematically evaluated.Moreover,except for popular microgrooves,little work has been carried out on the reaction of cells to the bionic structure.In this study,several micro-pillars mimicking cell morphology were prepared on Ti surfaces by lithography and contact printing(ICP)method,and they were further decorated with nanotube arrays by anodization technology.These surface modifications remarkablly increased the surface roughness of pristine Ti surface from 91.17 nm±5.57 nm to be more than 1000 nm,and reduced their water contact angles from 68.3°±0.7°to be 16.9°±2.4°.Then,the effects of these hierarchical micron/nano scale patterns on the behaviors of MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis were studied,aiming to evaluate their performance in osseointegration,gingival epithelial sealing and antibacterial ability.Through an innovative scoring strategy,our findings showed that square micro-pillars with 6μm width and 2μm height combined with 85 nm diameter nanotubes was suitable for implant neck design,while square micro-pillars with 3μm width and 3.6μm height combined with 55 nm diameter nanotubes was the best for implant body design.Our study reveals the synergistic effect of the hierarchical micron/nano scale patterns on MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis functions.It provides insight into the design of biomedical implant surfaces.
基金supported by the Innovation Funds for Scientific Research Academy of Guangxi Environmental Protection(No.HKYCX-2015-5)Guangxi key research and development plan for Department of Guangxi Science(No.GUIKEAB16380292)+1 种基金the China Ministry of Environmental Protection's Special Funds for Scientific Research on Public Welfare(No.201309016)the support from the operation and maintenance teams of the environment observation stations in Beihai
文摘A single particle aerosol mass spectrometer was deployed to measure the changes of single particle species and sizes during March 2015 in Weizhou Island of the Beibu Gulf, Guangxi province, South China. In this campaign, a total of 3,100,597 particles were sized, and 25.8%particles with both positive and negative mass spectrum were collected and 24.8%characterized in combination with the ART-2 a neural network algorithm. The distribution of sized particles was mainly in from 520 to 600 nm, and the diameters ranging from 340 to1000 nm accounted for above 90%. Eight types of particles were classified: Elemental Carbon containing(EC), Organic Carbon containing(OC), EC and OC combined containing particles,Na containing particles, K containing particles(K), Levoglucosan containing particles,mineral containing particles, and Heavy Metal containing particles(HM). EC, OC and K were the major containing particles, which accounted for 84.3% in the eight types particles. The relative ratio and size distribution of the three types were EC(48.1%, 620 nm), OC(12.7%,440 nm), and K(23.5%, 600 nm), respectively. The three types of particles were a bit increasing ratios compared with those in clean periods during haze pollution periods.Combined with the back-trajectory results from the Hysplit-4 model and local pollution sources revealed that the ambient air quality on the Weizhou Island may be influenced by biomass burning in the Indochina Peninsula(biomass burning in the Indochina Peninsula)from the transportation on higher level atmospheric layer and by mainland of south China located northeast of Weizhou Island on the ground.
