Performances and efficiencies of displacement ventilation(DV) and partial ventilation(PV) for industrial halls of different configurations as well as the heat and mass transports within the industrial halls were numer...Performances and efficiencies of displacement ventilation(DV) and partial ventilation(PV) for industrial halls of different configurations as well as the heat and mass transports within the industrial halls were numerically investigated. Three levels of Rayleigh number(5.8×1010, 1.0×1012 and 2.1×1012) and two values of source contaminant flux(5 mg/s and 50 mg/s) were considered. The inlet Reynolds numbers were 2×104, 5×104, 1.5×105 and 4.5×105 for DV and 5×105, 1×106, 2×106 and 4×106 for PV, respectively. From the results, it is concluded that the above parameters have very complex impacts on the conjugated heat and mass transports. From points of view of acceptable indoor air quality and ventilation efficiency, PV at Re=1×106 with side-located sources and 65% of the supply air extracted through floor level outlets is the best choice when Ra=5.8×1010. However, DVs at Re=5×104 and Re=1.5×105with center-located sources and floor-mounted air suppliers are the best choices for Ra=1.0×1012 and Ra=2.1×1012, respectively. When source contaminant flux reaches 50 mg/s, local extraction as a supplement of general ventilation is recommended. The results can be a first approximation to 3D numerical investigation and preliminary ventilation system design guidelines for high-rise industrial halls.展开更多
To reduce heat loss and save cost, a combination decision model of reverb aluminum holding furnace linings in aluminum casting industry was established based on economic thickness method, and was resolved using simula...To reduce heat loss and save cost, a combination decision model of reverb aluminum holding furnace linings in aluminum casting industry was established based on economic thickness method, and was resolved using simulated annealing. Meanwhile, a three-dimensional mathematical model of aluminum holding furnace linings was developed and integrated with user-defined heat load distribution regime model. The optimal combination was as follows: side wall with 80 mm alumino-silicate fiber felts, 232 mm diatomite brick and 116 mm chamotte brick; top wall with 50 mm clay castables, 110 mm alumino-silicate fiber felts and 200 mm refractory concrete;and bottom wall with 232 mm high-alumina brick, 60 mm clay castables and 68 mm diatomite brick. Lining temperature from high to low was successively bottom wall, side wall, and top wall. Lining temperature gradient in increasing order of magnitude was refractory layer and insulation layer. It was indicated that the results of combination optimization of aluminum holding furnace linings were valid and feasible, and its thermo-physical mechanism and cost characteristics were reasonably revealed.展开更多
There has been increasing interests in developing land use models for small urban areas for various planning applications such as air quality conformity analysis. The output of a land use model can serve as a major in...There has been increasing interests in developing land use models for small urban areas for various planning applications such as air quality conformity analysis. The output of a land use model can serve as a major input to a transportation model; conversely, transportation model output can provide a critical input to a land use model. The connection between the two models can be achieved by an accessibility measure. This paper presents an iterative approach to solving a regression-based land use model and a transportation model with combined trip distribution- assignment. A case study using data from a small urban area is presented to illustrate the application of the proposed modeling framework. Tests show that the procedures can converge, and the modeling framework can be a valuable tool for planners and decision-makers in evaluating land use policies and transportation investment strategies.展开更多
AIM: To study the relationship between the patterns of postprandial peristalsis and transduodenal bolus transport in healthy subjects. METHODS: Synchronous recording of chyme transport and peristaltic activity was per...AIM: To study the relationship between the patterns of postprandial peristalsis and transduodenal bolus transport in healthy subjects. METHODS: Synchronous recording of chyme transport and peristaltic activity was performed during the fasting state and after administration of a test meal using a special catheter device with cascade configuration of impedance electrodes and solid-state pressure transducers. The catheter was placed into the duodenum, where the f irst channel was located in the f irst part of the duodenum and the last channel at the duodenojejunal junction. After identif ication of previously def ined chyme transport patterns the associated peristaltic patterns were analyzed. RESULTS: The interdigestive phase 3 complex was reliably recorded with both techniques. Of 497 analyzed impedance bolus transport events, 110 (22%) were short-spanned propulsive, 307 (62%) long-spanned propulsive, 70 (14%) complex propulsive, and 10 (2%) retrograde transport. Short-spanned chyme transports were predominantly associated with stationary or propagated contractions propagated over short distance. Long-spanned and complex chyme transports were predominantly associated with propulsive peristaltic patterns, which were frequently complex and comprised multiple contractions. Propagated double wave contraction, propagated contraction with a clustered contraction, and propagated cluster of contractions have been identif ied to be an integralted part of a peristaltic sequence in human duodenum. CONCLUSION: Combined impedancometry and manometry improves the analysis of the peristaltic patterns that are associated with postprandial transduodenal chymetransport. Postprandial transduodenal bolus transport is regulated by propulsive peristaltic patterns, which are frequently complex but well organized. This f inding should be taken into consideration in the analysis of intestinal motility studies.展开更多
Based on the density functional theory combined with the nonequilibrium Green function methodology,we have studied the thermally-driven spin-dependent transport properties of a combinational molecular junction consist...Based on the density functional theory combined with the nonequilibrium Green function methodology,we have studied the thermally-driven spin-dependent transport properties of a combinational molecular junction consisting of a planar four-coordinate Fe molecule and a 15,16-dinitrile dihydropyrene/cyclophanediene molecule,with single-walled carbon nanotube bridge and electrode.Our results show that the magnetic field and light can effectively regulate the thermallydriven spin-dependent currents.Perfect thermal spin-filtering effect and good thermal switching effect are realized.The results are explained by the Fermi-Dirac distribution function,the spin-resolved transmission spectra,the spatial distribution of molecular projected self-consistent Hamiltonian orbitals,and the spin-resolved current spectra.On the basis of these thermally-driven spin-dependent transport properties,we have further designed three basic thermal spin molecular AND,OR,and NOT gates.展开更多
基金Project(2011BAJ03B07)supported by National Twelve Five-year Science and Technology Support Program of ChinaProject supported by the China Scholarship Council+1 种基金Project(51276057,51376198)supported by the National Natural Science Foundation of ChinaProject(CX2014B064)supported by Hunan Provincial Innovation Foundation for Postgraduate,China
文摘Performances and efficiencies of displacement ventilation(DV) and partial ventilation(PV) for industrial halls of different configurations as well as the heat and mass transports within the industrial halls were numerically investigated. Three levels of Rayleigh number(5.8×1010, 1.0×1012 and 2.1×1012) and two values of source contaminant flux(5 mg/s and 50 mg/s) were considered. The inlet Reynolds numbers were 2×104, 5×104, 1.5×105 and 4.5×105 for DV and 5×105, 1×106, 2×106 and 4×106 for PV, respectively. From the results, it is concluded that the above parameters have very complex impacts on the conjugated heat and mass transports. From points of view of acceptable indoor air quality and ventilation efficiency, PV at Re=1×106 with side-located sources and 65% of the supply air extracted through floor level outlets is the best choice when Ra=5.8×1010. However, DVs at Re=5×104 and Re=1.5×105with center-located sources and floor-mounted air suppliers are the best choices for Ra=1.0×1012 and Ra=2.1×1012, respectively. When source contaminant flux reaches 50 mg/s, local extraction as a supplement of general ventilation is recommended. The results can be a first approximation to 3D numerical investigation and preliminary ventilation system design guidelines for high-rise industrial halls.
基金Supported by the National Natural Science Foundation of China(51306001)the Natural Science Foundation of Anhui Province(1408085QG138)+1 种基金the Natural Science Foundation of Anhui Technology University(QZ201303,QS201304)the Student Research Training Program of Anhui University of Technology(AH201310360120)
文摘To reduce heat loss and save cost, a combination decision model of reverb aluminum holding furnace linings in aluminum casting industry was established based on economic thickness method, and was resolved using simulated annealing. Meanwhile, a three-dimensional mathematical model of aluminum holding furnace linings was developed and integrated with user-defined heat load distribution regime model. The optimal combination was as follows: side wall with 80 mm alumino-silicate fiber felts, 232 mm diatomite brick and 116 mm chamotte brick; top wall with 50 mm clay castables, 110 mm alumino-silicate fiber felts and 200 mm refractory concrete;and bottom wall with 232 mm high-alumina brick, 60 mm clay castables and 68 mm diatomite brick. Lining temperature from high to low was successively bottom wall, side wall, and top wall. Lining temperature gradient in increasing order of magnitude was refractory layer and insulation layer. It was indicated that the results of combination optimization of aluminum holding furnace linings were valid and feasible, and its thermo-physical mechanism and cost characteristics were reasonably revealed.
文摘There has been increasing interests in developing land use models for small urban areas for various planning applications such as air quality conformity analysis. The output of a land use model can serve as a major input to a transportation model; conversely, transportation model output can provide a critical input to a land use model. The connection between the two models can be achieved by an accessibility measure. This paper presents an iterative approach to solving a regression-based land use model and a transportation model with combined trip distribution- assignment. A case study using data from a small urban area is presented to illustrate the application of the proposed modeling framework. Tests show that the procedures can converge, and the modeling framework can be a valuable tool for planners and decision-makers in evaluating land use policies and transportation investment strategies.
基金Supported by a grant of the University of Aachen "START-Project"
文摘AIM: To study the relationship between the patterns of postprandial peristalsis and transduodenal bolus transport in healthy subjects. METHODS: Synchronous recording of chyme transport and peristaltic activity was performed during the fasting state and after administration of a test meal using a special catheter device with cascade configuration of impedance electrodes and solid-state pressure transducers. The catheter was placed into the duodenum, where the f irst channel was located in the f irst part of the duodenum and the last channel at the duodenojejunal junction. After identif ication of previously def ined chyme transport patterns the associated peristaltic patterns were analyzed. RESULTS: The interdigestive phase 3 complex was reliably recorded with both techniques. Of 497 analyzed impedance bolus transport events, 110 (22%) were short-spanned propulsive, 307 (62%) long-spanned propulsive, 70 (14%) complex propulsive, and 10 (2%) retrograde transport. Short-spanned chyme transports were predominantly associated with stationary or propagated contractions propagated over short distance. Long-spanned and complex chyme transports were predominantly associated with propulsive peristaltic patterns, which were frequently complex and comprised multiple contractions. Propagated double wave contraction, propagated contraction with a clustered contraction, and propagated cluster of contractions have been identif ied to be an integralted part of a peristaltic sequence in human duodenum. CONCLUSION: Combined impedancometry and manometry improves the analysis of the peristaltic patterns that are associated with postprandial transduodenal chymetransport. Postprandial transduodenal bolus transport is regulated by propulsive peristaltic patterns, which are frequently complex but well organized. This f inding should be taken into consideration in the analysis of intestinal motility studies.
基金Project supported by the Natural Science Foundation of Shandong Province,China(Grant No.ZR2021MA059)the Major Scientific and Technological Innovation Project(MSTIP)of Shandong Province,China(Grant No.2019JZZY010209)。
文摘Based on the density functional theory combined with the nonequilibrium Green function methodology,we have studied the thermally-driven spin-dependent transport properties of a combinational molecular junction consisting of a planar four-coordinate Fe molecule and a 15,16-dinitrile dihydropyrene/cyclophanediene molecule,with single-walled carbon nanotube bridge and electrode.Our results show that the magnetic field and light can effectively regulate the thermallydriven spin-dependent currents.Perfect thermal spin-filtering effect and good thermal switching effect are realized.The results are explained by the Fermi-Dirac distribution function,the spin-resolved transmission spectra,the spatial distribution of molecular projected self-consistent Hamiltonian orbitals,and the spin-resolved current spectra.On the basis of these thermally-driven spin-dependent transport properties,we have further designed three basic thermal spin molecular AND,OR,and NOT gates.
