基于相似原理,建立了八流连铸中间包的1:2物理模型,通过水模实验测定了1#~4#控流方案下中间包内的停留时间分布(Residence time distribution,简称RTD)。通过推导提出了多流连铸中间包的RTD曲线分析方法,并以此分析了中间包内...基于相似原理,建立了八流连铸中间包的1:2物理模型,通过水模实验测定了1#~4#控流方案下中间包内的停留时间分布(Residence time distribution,简称RTD)。通过推导提出了多流连铸中间包的RTD曲线分析方法,并以此分析了中间包内的流体平均停留时间、流动模式和各流流动一致性,进而对控流装置进行优化选择。研究结果表明,3#控流方案能较好地改善中间包内的流动特征。展开更多
A three-dimensional numerical model was established to simulate the hydrodynamics within an octagonal tank of a recirculating aquaculture system. The realizable k-e turbulence model was applied to describe the flow, t...A three-dimensional numerical model was established to simulate the hydrodynamics within an octagonal tank of a recirculating aquaculture system. The realizable k-e turbulence model was applied to describe the flow, the discrete phase model (DPM) was applied to generate particle trajectories, and the governing equations are solved using the finite volume method. To validate this model, the numerical results were compared with data obtained from a full-scale physical model. The results show that: (1) the realizable k-e model applied for turbulence modeling describes well the flow pattern in octagonal tanks, giving an average relative error of velocities between simulated and measured values of 18% from contour maps of velocity magnitudes; (2) the DPM was applied to obtain particle trajectories and to simulate the rate of particle removal from the tank. The average relative error of the removal rates between simulated and measured values was 11%. The DPM can be used to assess the self-cleaning capability of an octagonal tank; (3) a comprehensive account of the hydrodynamics within an octagonal tank can be assessed from simulations. The velocity distribution was uniform with an average velocity of 15 cm/s; the velocity reached 0.8 m/s near the inlet pipe, which can result in energy losses and cause wall abrasion; the velocity in tank corners was more than 15 cm/s, which suggests good water mixing, and there was no particle sedimentation. The percentage of particle removal for octagonal tanks was 90% with the exception of a little accumulation of 〈5 mm particle in the area between the inlet pipe and the wall. This study demonstrated a consistent numerical model of the hydrodynamics within octagonal tanks that can be further used in their design and optimization as well as promote the wide use of computational fluid dynamics in aquaculture engineering.展开更多
According to the basic characteristics of the activities of summer monsoon in the South China Sea, a standardized index, sI, has been designed that integrates a dynamic factor (southwesterly component) and a thermodyn...According to the basic characteristics of the activities of summer monsoon in the South China Sea, a standardized index, sI, has been designed that integrates a dynamic factor (southwesterly component) and a thermodynamic factor (OLR) for the indication of summer monsoon in the South China Sea. With the index determined for individual months of June, July and August and the entire summertime from 1975 to 1999, specific months and years are indicated that are either strong or weak in monsoon intensity. The variation is studied for the patterns and sI抯 relationship is revealed with the onset of summer monsoon and the precipitation in Guangdong province and China. The results show that there are quasi-10 and quasi-3-4 year cycles in the interannual variation of the monsoon over the past 25 years. When it has an early (late) onset, the summer monsoon is usually strong (weak). In the strong (weak) monsoon years, precipitation tends to be more (less) in the first raining season of the year but normal or less (normal) in the second, in the province, but it would be more (less) in northeastern China and most parts of the northern China and south of the lower reaches of the Changjiang River and less (more) in the middle and lower reaches of the river, western part of northern China and western China.展开更多
In the present paper, the authors review rece nt development of acupunct ure treatment of threatened abortion from 1) clinical application of "Linggui Ba fa"(灵龟八法Eight Methods of Intelligent Turtle), 2) ...In the present paper, the authors review rece nt development of acupunct ure treatment of threatened abortion from 1) clinical application of "Linggui Ba fa"(灵龟八法Eight Methods of Intelligent Turtle), 2) body acupoints , and 3) acup uncture combined with Chinese materia medica, and clinical study from 1) effect of acupuncture on the blood flow of uterus, and 2) effect of acupuncture on plas ma progesterone level. In addition, acupuncture therapy is also used to help wom en in gestation and can effectively raise the pregnant rate. "Lingg ui Bafa" is r ather effective in preventing threatened abortion and should be studied further.展开更多
文摘基于相似原理,建立了八流连铸中间包的1:2物理模型,通过水模实验测定了1#~4#控流方案下中间包内的停留时间分布(Residence time distribution,简称RTD)。通过推导提出了多流连铸中间包的RTD曲线分析方法,并以此分析了中间包内的流体平均停留时间、流动模式和各流流动一致性,进而对控流装置进行优化选择。研究结果表明,3#控流方案能较好地改善中间包内的流动特征。
基金Supported by the Application Research Project of Post-Doctoral Researchers in Qingdao(No.ZQ51201415037)the Modern Agriculture Industry System Construction of Special Funds(No.CARS-50-G10)+1 种基金the Special Project about Independent Innovation and Achievement Transformation of Shandong Province(No.2014ZZCX07102)the Key R&D Program of Jiangsu Province(No.BE2015328)
文摘A three-dimensional numerical model was established to simulate the hydrodynamics within an octagonal tank of a recirculating aquaculture system. The realizable k-e turbulence model was applied to describe the flow, the discrete phase model (DPM) was applied to generate particle trajectories, and the governing equations are solved using the finite volume method. To validate this model, the numerical results were compared with data obtained from a full-scale physical model. The results show that: (1) the realizable k-e model applied for turbulence modeling describes well the flow pattern in octagonal tanks, giving an average relative error of velocities between simulated and measured values of 18% from contour maps of velocity magnitudes; (2) the DPM was applied to obtain particle trajectories and to simulate the rate of particle removal from the tank. The average relative error of the removal rates between simulated and measured values was 11%. The DPM can be used to assess the self-cleaning capability of an octagonal tank; (3) a comprehensive account of the hydrodynamics within an octagonal tank can be assessed from simulations. The velocity distribution was uniform with an average velocity of 15 cm/s; the velocity reached 0.8 m/s near the inlet pipe, which can result in energy losses and cause wall abrasion; the velocity in tank corners was more than 15 cm/s, which suggests good water mixing, and there was no particle sedimentation. The percentage of particle removal for octagonal tanks was 90% with the exception of a little accumulation of 〈5 mm particle in the area between the inlet pipe and the wall. This study demonstrated a consistent numerical model of the hydrodynamics within octagonal tanks that can be further used in their design and optimization as well as promote the wide use of computational fluid dynamics in aquaculture engineering.
基金 Research on the Formation Mechanism and Prediction Theory of Severe Climate Disasters in China (G1998040900(I))
文摘According to the basic characteristics of the activities of summer monsoon in the South China Sea, a standardized index, sI, has been designed that integrates a dynamic factor (southwesterly component) and a thermodynamic factor (OLR) for the indication of summer monsoon in the South China Sea. With the index determined for individual months of June, July and August and the entire summertime from 1975 to 1999, specific months and years are indicated that are either strong or weak in monsoon intensity. The variation is studied for the patterns and sI抯 relationship is revealed with the onset of summer monsoon and the precipitation in Guangdong province and China. The results show that there are quasi-10 and quasi-3-4 year cycles in the interannual variation of the monsoon over the past 25 years. When it has an early (late) onset, the summer monsoon is usually strong (weak). In the strong (weak) monsoon years, precipitation tends to be more (less) in the first raining season of the year but normal or less (normal) in the second, in the province, but it would be more (less) in northeastern China and most parts of the northern China and south of the lower reaches of the Changjiang River and less (more) in the middle and lower reaches of the river, western part of northern China and western China.
文摘In the present paper, the authors review rece nt development of acupunct ure treatment of threatened abortion from 1) clinical application of "Linggui Ba fa"(灵龟八法Eight Methods of Intelligent Turtle), 2) body acupoints , and 3) acup uncture combined with Chinese materia medica, and clinical study from 1) effect of acupuncture on the blood flow of uterus, and 2) effect of acupuncture on plas ma progesterone level. In addition, acupuncture therapy is also used to help wom en in gestation and can effectively raise the pregnant rate. "Lingg ui Bafa" is r ather effective in preventing threatened abortion and should be studied further.