Two types of tube bundles are designed,which are,respectively,composed of six tubes arranged in the boiling chamber.The nucleate pool boiling performance of smooth tube bundles and sintered porous surface tube bundles...Two types of tube bundles are designed,which are,respectively,composed of six tubes arranged in the boiling chamber.The nucleate pool boiling performance of smooth tube bundles and sintered porous surface tube bundles with deionized water as a medium are experimentally studied at atmospheric and sub-atmospheric pressures,respectively.The experimental results indicate that the boiling heat transfer coefficients of the two types of tube bundles increase with the increase in pressure under vacuum conditions as they behave under ordinary pressure.As the pressure varies from 10 to 100 kPa,it also can be seen that the heat transfer coefficient of the sintered porous surface tube is increased by 0.2 to 4 times compared with the smooth one under the same operating parameters.In addition,the experimental data show that a definite bundle effect exists in both sintered porous surface tubes and smooth tubes under vacuum conditions.展开更多
Enhanced pool boiling heat transfer of the porous structure is critical to the thermal management technology.In this paper,pool boiling heat transfer experiments are performed on copper foam welded surfaces in de-ioni...Enhanced pool boiling heat transfer of the porous structure is critical to the thermal management technology.In this paper,pool boiling heat transfer experiments are performed on copper foam welded surfaces in de-ionized water to investigate the effects of basic parameters of copper foam on heat transfer enhancement.Boiling phenomenon is observed to facilitate the understanding of enhancement mechanism.The results show that copper foam welded surfaces can significantly enhance the pool boiling heat transfer performance,reduce the boiling incipience temperature by 7-9℃,and reach two times heat transfer coefficient compared with smooth plain surfaces due to numerous nucleation sites,extended surface areas,and enhanced turbulent effect.Pore density and thickness of foam have two side effects on heat transfer.展开更多
In this study,conductive polymer polyaniline(PANI)is employed to modify the anodes of benthic microbial fuel cells(BMFC).Four electrochemical methods are used to synthesize the polyaniline anodes;the results show that...In this study,conductive polymer polyaniline(PANI)is employed to modify the anodes of benthic microbial fuel cells(BMFC).Four electrochemical methods are used to synthesize the polyaniline anodes;the results show that the PANI modification,especially the pulse potential method for PANI synthesis could obviously improve the cell energy output and reduce the anode internal resistance.The anode is modified by PANI doped with Fe or Mn to further improve the BMFC performance.A maximum power density of 17.51 mW/m2 is obtained by PANI-Fe anode BMFC,which is 8.1 times higher than that of control.The PANI-Mn anode BMFC also gives a favorable maximum power density(16.78 mW/m2).Fe or Mn modification has better effect in improving the conductivity of polyaniline,thus improving the energy output of BMFCs.This work applying PANI composite anode into BMFC brings new development prospect and could promote the practical application of BMFC.展开更多
A series of hydrogenated microcrystalline silicon （μc-Si：H） p-layers for back surface field in crystalline silicon solar cells were deposited on glass substrates by the developed large area （45 cm×45 cm） pl...A series of hydrogenated microcrystalline silicon （μc-Si：H） p-layers for back surface field in crystalline silicon solar cells were deposited on glass substrates by the developed large area （45 cm×45 cm） plasma enhanced chemical vapour deposition processor operating at 13.56 MHz and various values of source gas trimethylboron （TMB） to H2 flowratio. The influence of deposition parameters on the large area p-layer performance was intensively studied, as well as the thin film uniformity, optical, electrical and structural performances by Raman, PTIR, Ellipsometry, etc. Arrhenius and Tauc plots were used to discuss the μc-Si：H thin film＇s activation energy and the defects state distribution. When amorphous-microcrystalline transition state was obtained, the deposited p-doped μc-Si：H layers showed specific resistance of 38.3 Ω^-1cm1 at the flowratio of 0.66% and high crystallinity of 45%-50% with no further treatment. The effect of source gas flowratio, deposition rate, and source gas partial pressure on μc-Si：H thin film＇s performance was also investigated.展开更多
Al-doped ZnO (AZO) nanocrystalline aggregates (NCAs) were prepared by a low cost colloid chemistry method and effects of the Al-doped concentration on the morphological and structural properties of the AZO NCAs were s...Al-doped ZnO (AZO) nanocrystalline aggregates (NCAs) were prepared by a low cost colloid chemistry method and effects of the Al-doped concentration on the morphological and structural properties of the AZO NCAs were studied. The dye adsorption ability of the AZO NCAs with various Al-doped concentrations was also investigated. Results indicate that the doping of the Al ions not only does not change the wurtzite structure of the ZnO crystal but also can reduce the crystallite grain size and the particle size distribution of the NCAs, which gives them a higher specific surface area and dye adsorption ability than that of the ZnO NCAs. The as-prepared AZO NCAs would be a promising material to be applied in the dye sensitized solar cells and water treatment.展开更多
基金The National Natural Science Foundation of China(No.50706012)
文摘Two types of tube bundles are designed,which are,respectively,composed of six tubes arranged in the boiling chamber.The nucleate pool boiling performance of smooth tube bundles and sintered porous surface tube bundles with deionized water as a medium are experimentally studied at atmospheric and sub-atmospheric pressures,respectively.The experimental results indicate that the boiling heat transfer coefficients of the two types of tube bundles increase with the increase in pressure under vacuum conditions as they behave under ordinary pressure.As the pressure varies from 10 to 100 kPa,it also can be seen that the heat transfer coefficient of the sintered porous surface tube is increased by 0.2 to 4 times compared with the smooth one under the same operating parameters.In addition,the experimental data show that a definite bundle effect exists in both sintered porous surface tubes and smooth tubes under vacuum conditions.
基金supported by the National Natural Science Foundation of China(No.52075249)the Foundation of Jiangsu Key Laboratory of Bionic Functional Materials(No.NJ2020026)
文摘Enhanced pool boiling heat transfer of the porous structure is critical to the thermal management technology.In this paper,pool boiling heat transfer experiments are performed on copper foam welded surfaces in de-ionized water to investigate the effects of basic parameters of copper foam on heat transfer enhancement.Boiling phenomenon is observed to facilitate the understanding of enhancement mechanism.The results show that copper foam welded surfaces can significantly enhance the pool boiling heat transfer performance,reduce the boiling incipience temperature by 7-9℃,and reach two times heat transfer coefficient compared with smooth plain surfaces due to numerous nucleation sites,extended surface areas,and enhanced turbulent effect.Pore density and thickness of foam have two side effects on heat transfer.
基金Project(HIT.NSRIF.2014128)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2014M551257)supported by the China Postdoctoral Science FoundationProject(WH20150208)supported by the Subject Development Foundation of Harbin Institute of Technology at Weihai,China
文摘In this study,conductive polymer polyaniline(PANI)is employed to modify the anodes of benthic microbial fuel cells(BMFC).Four electrochemical methods are used to synthesize the polyaniline anodes;the results show that the PANI modification,especially the pulse potential method for PANI synthesis could obviously improve the cell energy output and reduce the anode internal resistance.The anode is modified by PANI doped with Fe or Mn to further improve the BMFC performance.A maximum power density of 17.51 mW/m2 is obtained by PANI-Fe anode BMFC,which is 8.1 times higher than that of control.The PANI-Mn anode BMFC also gives a favorable maximum power density(16.78 mW/m2).Fe or Mn modification has better effect in improving the conductivity of polyaniline,thus improving the energy output of BMFCs.This work applying PANI composite anode into BMFC brings new development prospect and could promote the practical application of BMFC.
基金supported by the National "863" Project of China (Grant No.2006AA05Z409)the "Kaisi" Oversea R&D Schol-arship of Sun Yat-sen University
文摘A series of hydrogenated microcrystalline silicon （μc-Si：H） p-layers for back surface field in crystalline silicon solar cells were deposited on glass substrates by the developed large area （45 cm×45 cm） plasma enhanced chemical vapour deposition processor operating at 13.56 MHz and various values of source gas trimethylboron （TMB） to H2 flowratio. The influence of deposition parameters on the large area p-layer performance was intensively studied, as well as the thin film uniformity, optical, electrical and structural performances by Raman, PTIR, Ellipsometry, etc. Arrhenius and Tauc plots were used to discuss the μc-Si：H thin film＇s activation energy and the defects state distribution. When amorphous-microcrystalline transition state was obtained, the deposited p-doped μc-Si：H layers showed specific resistance of 38.3 Ω^-1cm1 at the flowratio of 0.66% and high crystallinity of 45%-50% with no further treatment. The effect of source gas flowratio, deposition rate, and source gas partial pressure on μc-Si：H thin film＇s performance was also investigated.
基金supported by the National High Technology Research and Development Program of China (Grant No. 2009AA03Z218)the National Natural Science Foundation of China (Grant No. 90923012)
文摘Al-doped ZnO (AZO) nanocrystalline aggregates (NCAs) were prepared by a low cost colloid chemistry method and effects of the Al-doped concentration on the morphological and structural properties of the AZO NCAs were studied. The dye adsorption ability of the AZO NCAs with various Al-doped concentrations was also investigated. Results indicate that the doping of the Al ions not only does not change the wurtzite structure of the ZnO crystal but also can reduce the crystallite grain size and the particle size distribution of the NCAs, which gives them a higher specific surface area and dye adsorption ability than that of the ZnO NCAs. The as-prepared AZO NCAs would be a promising material to be applied in the dye sensitized solar cells and water treatment.
