t According to a general representation of physical scale factor of RCS for variance in the size of simply shaped scatterers, a novel RCS model-testing method is described. The computed results of the prototype scatte...t According to a general representation of physical scale factor of RCS for variance in the size of simply shaped scatterers, a novel RCS model-testing method is described. The computed results of the prototype scatterers by this method from the model-testing agree well with their measured values both for two kinds of simply shaped scatterers, cylinders and ladder-shaped plates.展开更多
The lack and pollution of water resource make wastewater reuse necessary. The pilot scale long-term tests for submerged membrane bioreactor were conducted to treat the effluents of anaerobic or aerobic treatment proce...The lack and pollution of water resource make wastewater reuse necessary. The pilot scale long-term tests for submerged membrane bioreactor were conducted to treat the effluents of anaerobic or aerobic treatment process for the high-strength Chinese traditional medicine wastewater. This article was focused on the feasibility of the wastewater treatment and reuse at shorter hydraulic retention time （HRT） of 5.0, 3.2 and 2.13 h. MLSS growth, membrane flux, vacuum values and chemical cleaning periods were also investigated. The experimental results of treating two-phase anaerobic treatment effluent demonstrated that the CODfilt was less than 100 mg/L when the influent COD was between 500-10000 mg/L at HRT of 5.0 h, which could satisfy the normal discharged standard in China. The experimental results to treat cross flow aerobic reactor effluent demonstrated that the average value of CODfilt was 17.28 mg/L when the average value of influent COD was 192.84 mg/L at HRT of 2.13 h during 106 d, which could completely meet the normal standard for water reuse. The maximum MLSS and MLVSS reached 24000 and 14500 mg/L at HRT of 3.2 h respectively. Membrane flux had maximal resume degrees of 94.7% at vacuum value of 0.02 MPa after cleaning. Chemical cleaning periods of membrane module were 150 d. A simulation model of operational parameters was also established based on the theory of back propagation neural network and linear regression of traditional mathematical model. The simulation model showed that the optimum operational parameters were suggested as follows： HRT was 5.0 h, SRT was 100 d, the range of COD loading rate was between 10.664-20.451 kg/（m3.d）, the range of MLSS was between 7543-13694 mg/L.展开更多
Many single-tower reinforced concrete core wall-steel frame （RCC-SF） buildings have been built in China, but there are no buildings of different-height multi-tower hybrid system. A multi-tower RCC-SF tall building w...Many single-tower reinforced concrete core wall-steel frame （RCC-SF） buildings have been built in China, but there are no buildings of different-height multi-tower hybrid system. A multi-tower RCC-SF tall building was thus studied because of its structural complexity and irregularity. First, a 1/15 scaled model structure was designed and tested on the shake table under minor, moderate, and major earthquake levels. Then, the dynamic responses of the model structure were interpreted to those of the prototype structure according to the similitude theory. Experimental results demonstrate that, despite the complexity of the structure, the lateral deformation bends as the ＂bending type＂ and the RC core walls contribute more than the steel frames to resist seismic loads. The maximum inter-story drift of the complex building under minor earthquakes is slightly beyond the elastic limitation specified in the Chinese code, and meets code requirements under major earthquakes. From the test results some suggestions are provided that could contribute favorable effect on the seismic behavior and the displacement of the building.展开更多
Viscoelastic（VE） dampers, with their stiffness and energy dissipation capabilities, have been widely used in civil engineering for mitigating wind-induced vibration and seismic responses of structures, thus enhancin...Viscoelastic（VE） dampers, with their stiffness and energy dissipation capabilities, have been widely used in civil engineering for mitigating wind-induced vibration and seismic responses of structures, thus enhancing the comfort of residents and serviceability of equipment inside. In past relevant research, most analytical models for characterizing the mechanical behavior of VE dampers were verified by comparing their predictions with performance test results from small-scale specimens, which might not adequately or conservatively represent the actual behavior of full-scale dampers, especially with regard to the ambient temperature, temperature rise, and heat convection effects. Thus, in this study, by using a high-performance testing facility with a temperature control system, full-scale VE dampers were dynamically tested with different displacement amplitudes, excitation frequencies, and ambient temperatures. By comparing the analytical predictions with the experimental results, it is demonstrated that adopting the fractional derivative method together with considering the effects of excitation frequencies, ambient temperatures, temperature rises, softening, and hardening, can reproduce the design performance of full-scale VE dampers very well.展开更多
文摘t According to a general representation of physical scale factor of RCS for variance in the size of simply shaped scatterers, a novel RCS model-testing method is described. The computed results of the prototype scatterers by this method from the model-testing agree well with their measured values both for two kinds of simply shaped scatterers, cylinders and ladder-shaped plates.
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA601310).
文摘The lack and pollution of water resource make wastewater reuse necessary. The pilot scale long-term tests for submerged membrane bioreactor were conducted to treat the effluents of anaerobic or aerobic treatment process for the high-strength Chinese traditional medicine wastewater. This article was focused on the feasibility of the wastewater treatment and reuse at shorter hydraulic retention time （HRT） of 5.0, 3.2 and 2.13 h. MLSS growth, membrane flux, vacuum values and chemical cleaning periods were also investigated. The experimental results of treating two-phase anaerobic treatment effluent demonstrated that the CODfilt was less than 100 mg/L when the influent COD was between 500-10000 mg/L at HRT of 5.0 h, which could satisfy the normal discharged standard in China. The experimental results to treat cross flow aerobic reactor effluent demonstrated that the average value of CODfilt was 17.28 mg/L when the average value of influent COD was 192.84 mg/L at HRT of 2.13 h during 106 d, which could completely meet the normal standard for water reuse. The maximum MLSS and MLVSS reached 24000 and 14500 mg/L at HRT of 3.2 h respectively. Membrane flux had maximal resume degrees of 94.7% at vacuum value of 0.02 MPa after cleaning. Chemical cleaning periods of membrane module were 150 d. A simulation model of operational parameters was also established based on the theory of back propagation neural network and linear regression of traditional mathematical model. The simulation model showed that the optimum operational parameters were suggested as follows： HRT was 5.0 h, SRT was 100 d, the range of COD loading rate was between 10.664-20.451 kg/（m3.d）, the range of MLSS was between 7543-13694 mg/L.
基金National Natural Science Foundation of China Under Grant No. 50708071National Basic Research of China Under Grant No. 2007CB714202+1 种基金National Key Technology R&D Program Under Grant No. 2006BAJ13B01Shanghai Educational Development Foundation Under Grant No. 2007CG27
文摘Many single-tower reinforced concrete core wall-steel frame （RCC-SF） buildings have been built in China, but there are no buildings of different-height multi-tower hybrid system. A multi-tower RCC-SF tall building was thus studied because of its structural complexity and irregularity. First, a 1/15 scaled model structure was designed and tested on the shake table under minor, moderate, and major earthquake levels. Then, the dynamic responses of the model structure were interpreted to those of the prototype structure according to the similitude theory. Experimental results demonstrate that, despite the complexity of the structure, the lateral deformation bends as the ＂bending type＂ and the RC core walls contribute more than the steel frames to resist seismic loads. The maximum inter-story drift of the complex building under minor earthquakes is slightly beyond the elastic limitation specified in the Chinese code, and meets code requirements under major earthquakes. From the test results some suggestions are provided that could contribute favorable effect on the seismic behavior and the displacement of the building.
基金Science and Technology Authority of Taiwan under Grant No.107-2221-E-492-004-
文摘Viscoelastic（VE） dampers, with their stiffness and energy dissipation capabilities, have been widely used in civil engineering for mitigating wind-induced vibration and seismic responses of structures, thus enhancing the comfort of residents and serviceability of equipment inside. In past relevant research, most analytical models for characterizing the mechanical behavior of VE dampers were verified by comparing their predictions with performance test results from small-scale specimens, which might not adequately or conservatively represent the actual behavior of full-scale dampers, especially with regard to the ambient temperature, temperature rise, and heat convection effects. Thus, in this study, by using a high-performance testing facility with a temperature control system, full-scale VE dampers were dynamically tested with different displacement amplitudes, excitation frequencies, and ambient temperatures. By comparing the analytical predictions with the experimental results, it is demonstrated that adopting the fractional derivative method together with considering the effects of excitation frequencies, ambient temperatures, temperature rises, softening, and hardening, can reproduce the design performance of full-scale VE dampers very well.
