For thousands of years, the North China Plain has been one of the most productive agricultural regions of the country, and the future of this region will be determined in large part by how global climatic change impac...For thousands of years, the North China Plain has been one of the most productive agricultural regions of the country, and the future of this region will be determined in large part by how global climatic change impact regional conditions and by actions taken to mitigate or adapt to impacts of climate change. It is of great importance to estimate the effects of carbon sequestration measures taken to mitigate or adapt to impacts of climate change with proper economic outcome models. This paper aims to measure the effects of the most commonly used carbon sequestration measures, fertilization and irrigation, on agricultural production in the North China Plain.展开更多
Transport of nanoparticles and coagulation is simulated with the combination of CFD in a circular bend. The Taylor-expansion moment method(TEMOM)is employed to study dynamics of nanoparticles with Brownian motion,base...Transport of nanoparticles and coagulation is simulated with the combination of CFD in a circular bend. The Taylor-expansion moment method(TEMOM)is employed to study dynamics of nanoparticles with Brownian motion,based on the flow field from numerical simulation.A fully developed flow pattern in the present simulation is compared with previous numerical results for validating the model and computational code.It is found that for the simulated particulate flow system,the particle mass concentration,number concentration,particle polydispersity, mean particle diameter and geometric standard deviation over cross-section increase with time.The distribution of particle mass concentration at different time is independent of the initial particle size.More particles are concen-trated at outer edge of the bend.Coagulation plays more important role at initial stage than that in the subsequent period.The increase of Reynolds number and initial particle size leads to the increase of particle number concentration.The particle polydispersity,mean particle diameter and geometric standard deviation increase with decreasing Reynolds number and initial particle size.展开更多
Fiber Bragg grating under transverse force on a small grating section is studied by numerical simulation and experimentation. A numerical simulation based on the transfer matrix method is used to calculate the consequ...Fiber Bragg grating under transverse force on a small grating section is studied by numerical simulation and experimentation. A numerical simulation based on the transfer matrix method is used to calculate the consequent changes in reflected spectrum. The reflected spectra of the FBG subjected to the transverse force split into two main peaks, and the split point shifted linearly and periodically versus the applied force. The split point is shifted in the bandwidth with the period of 11N, and the sensitivity of the split point wavelength shift versus the applied force is 0.05 nm/N in one period. The experimental results show good agreement with the simulation analysis.展开更多
Using ANSYS-CFX, a general purpose fluid dynamics program, the vortex-induced vibration(VIV) of a variable cross-section cylinder is simulated under uniform current with high Reynolds numbers. Large eddy simulation(LE...Using ANSYS-CFX, a general purpose fluid dynamics program, the vortex-induced vibration(VIV) of a variable cross-section cylinder is simulated under uniform current with high Reynolds numbers. Large eddy simulation(LES) is conducted for studying the fluid-structure interaction. The vortex shedding in the wake, the motion trajectories of a cylinder, the variation of drag and lift forces on the cylinder are analyzed. The results show that the vortices of variable cross-section cylinder are chaotic and are varying along the cylinder. In places where cross-sections are changing significantly, the vortices are more irregular. The motion trail of the cylinder is almost the same but irregular. The drag and lift coefficients of the cylinder are varying with the changes of diameters.展开更多
A method of forecasting total seismic energy induced by longwall exploitation, based on changes in ground subsidence, is presented in the form of a linear regression model with one with one independent variable. In th...A method of forecasting total seismic energy induced by longwall exploitation, based on changes in ground subsidence, is presented in the form of a linear regression model with one with one independent variable. In the method, ground subsidence is described with a cross-section area of a subsidence trough Pw along a line of observations in the direction of an advancing longwall front, approximately along the axis of the longwall area. Total seismic energy is determined on the basis of seismic energy data of tremors induced by exploitation. The presentation consists of a detailed method and evaluation of its predictive ability for the area of longwall exploitation within the region of one of the coal mines in the Upper Silesian Coal Basin. This method can be used for forecasting the total seismic energy released by tremors within the area directly connected with the exploitation, in which the seismic activity induced by this exploitation occurs. The estimation of the parameters of the determined model should each time be carried out with investigations of the correctness of the model. The method cannot be applied when the number of recorded phenomena is small and when there is insufficient data to make it possible to calculate the index Pw.展开更多
The flow resistance of stent with different shapes of wire cross-section can be considered as a factor that influences the condition of inflow and outflow through the stent wire. Different from the traditional stents,...The flow resistance of stent with different shapes of wire cross-section can be considered as a factor that influences the condition of inflow and outflow through the stent wire. Different from the traditional stents, a novel stent with triangular wire cross-section was proposed, and numerical simulations were performed to compare the hemodynamic effect of the novel stent with that of traditional ones. Three constructed aneurysm models were treated with a different kin^l of stent separately, including one with bare circular wire cross-section stent （named CM）, one with bare rectangular wire cross-section stent （named RM）, one with bare triangular cross-section stent （named TM）. An unstented aneurysm model was also constructed to serve as a control （named UM）. Numerical simulations of the fluid-structure interaction in these four models were performed under the same boundary conditions using finite element method. The simulation results demonstrated the resistance of the novel stent is lower than RM stent, but higher than that of CM stent. TM stent attributes a higher velocity decreasing and a longer turnover time compared with CM stent. The distribution of wall shear stress indicated the possibility of aneurysm development along the distal wall was higher than the proximal wall, and the top of aneurysm was in the highest risk of rupture.展开更多
The traditional Contour Tracing algorithm works on the binary image. It is developed that a new model called Facula Diffusion which can work directly on gray-scaled images according to the principle of human vision. T...The traditional Contour Tracing algorithm works on the binary image. It is developed that a new model called Facula Diffusion which can work directly on gray-scaled images according to the principle of human vision. The diffusion operation is controlled by four factors including approximation, closing, length-limiting, and hit-rate. Based on this model, three shape indices, i. e., dimension index, abnormity index, and fluctuation index, were put forward to describe the shape of objects. The rule of shape indices selection was discussed subsequently. Finally, the fibers in polyester/cotton blended yam are classified and the blending ratio is determined.展开更多
Landslides are a type of natural disaster that can cause substantial harm to humanity.Monitoring and predicting the initiation of potential landslides is critical to avoiding losses due to disasters and economic activ...Landslides are a type of natural disaster that can cause substantial harm to humanity.Monitoring and predicting the initiation of potential landslides is critical to avoiding losses due to disasters and economic activities.The impact of the controlled-source audio-frequency magnetotelluric method on investigating landslide surfaces is assessed through numerical simulations with a finite element approach.A Dirichlet boundary condition is selected to match the truncated boundary,resulting in a remarkable improvement in simulation effi ciency.Rederivation of the formulas for a layered medium adept to the controlled-source audiofrequency magnetotelluric method is necessary to determine the electromagnetic fi eld at any location along the truncated boundary.After the reliability evaluation of the new codes,a landslide model with a slide surface is designed,and the characteristics of its electromagnetic fi eld and the apparent resistivity are studied.Instead of the total electromagnetic fi eld,which is strongly infl uenced by topography variation,the apparent resistivity should be used for sliding surface detection.The normalized pure anomalous electromagnetic fi eld may also be employed to quickly assess the detectability of the sliding surface.Overall,this study demonstrates that the controlled-source audio-frequency magnetotelluric method can be employed for investigating landslides,and recommends survey parameters,including confi guration,frequency range,and length of survey line in landslide exploration.展开更多
Abstract In the context of the left-right twin Higgs （LRTH） model, we have studied the charged Higgs bosons production processes e＋e-（γγ） →tbФ- at the International Linear Collider （ILC）. It is found that t...Abstract In the context of the left-right twin Higgs （LRTH） model, we have studied the charged Higgs bosons production processes e＋e-（γγ） →tbФ- at the International Linear Collider （ILC）. It is found that the cross sections of these two processes could reach a few Fo with reasonable parameter values. With the yearly integrated luminosity of L 500 fb-1 expected at the ILC, one could collect hundreds up to thousands of charged ttiggs events via these two processes. Therefore, our researches in this paper can help us search for charged Higgs bosons, and furthermore, to test the LRTH model.展开更多
基金Supported by the National Scientific Foundation of China(7087311840801231)+5 种基金the Chinese Academy of Sciences(KZCX2-YW-305-2KZCX2-YW-326-1)the Ministry of Science and Technology of China(2006DFB9192012008BAC43B012008BAK47B022008BAK50B06)~~
文摘For thousands of years, the North China Plain has been one of the most productive agricultural regions of the country, and the future of this region will be determined in large part by how global climatic change impact regional conditions and by actions taken to mitigate or adapt to impacts of climate change. It is of great importance to estimate the effects of carbon sequestration measures taken to mitigate or adapt to impacts of climate change with proper economic outcome models. This paper aims to measure the effects of the most commonly used carbon sequestration measures, fertilization and irrigation, on agricultural production in the North China Plain.
基金Supported by the Major Program of the National Natural Science Foundation of China（10632070）
文摘Transport of nanoparticles and coagulation is simulated with the combination of CFD in a circular bend. The Taylor-expansion moment method(TEMOM)is employed to study dynamics of nanoparticles with Brownian motion,based on the flow field from numerical simulation.A fully developed flow pattern in the present simulation is compared with previous numerical results for validating the model and computational code.It is found that for the simulated particulate flow system,the particle mass concentration,number concentration,particle polydispersity, mean particle diameter and geometric standard deviation over cross-section increase with time.The distribution of particle mass concentration at different time is independent of the initial particle size.More particles are concen-trated at outer edge of the bend.Coagulation plays more important role at initial stage than that in the subsequent period.The increase of Reynolds number and initial particle size leads to the increase of particle number concentration.The particle polydispersity,mean particle diameter and geometric standard deviation increase with decreasing Reynolds number and initial particle size.
基金This paper was supported by China National Science Foundation(60377002) .
文摘Fiber Bragg grating under transverse force on a small grating section is studied by numerical simulation and experimentation. A numerical simulation based on the transfer matrix method is used to calculate the consequent changes in reflected spectrum. The reflected spectra of the FBG subjected to the transverse force split into two main peaks, and the split point shifted linearly and periodically versus the applied force. The split point is shifted in the bandwidth with the period of 11N, and the sensitivity of the split point wavelength shift versus the applied force is 0.05 nm/N in one period. The experimental results show good agreement with the simulation analysis.
基金supported by the National Natural Science Foundation of China (Nos. 51179179 and 51079136)
文摘Using ANSYS-CFX, a general purpose fluid dynamics program, the vortex-induced vibration(VIV) of a variable cross-section cylinder is simulated under uniform current with high Reynolds numbers. Large eddy simulation(LES) is conducted for studying the fluid-structure interaction. The vortex shedding in the wake, the motion trajectories of a cylinder, the variation of drag and lift forces on the cylinder are analyzed. The results show that the vortices of variable cross-section cylinder are chaotic and are varying along the cylinder. In places where cross-sections are changing significantly, the vortices are more irregular. The motion trail of the cylinder is almost the same but irregular. The drag and lift coefficients of the cylinder are varying with the changes of diameters.
文摘A method of forecasting total seismic energy induced by longwall exploitation, based on changes in ground subsidence, is presented in the form of a linear regression model with one with one independent variable. In the method, ground subsidence is described with a cross-section area of a subsidence trough Pw along a line of observations in the direction of an advancing longwall front, approximately along the axis of the longwall area. Total seismic energy is determined on the basis of seismic energy data of tremors induced by exploitation. The presentation consists of a detailed method and evaluation of its predictive ability for the area of longwall exploitation within the region of one of the coal mines in the Upper Silesian Coal Basin. This method can be used for forecasting the total seismic energy released by tremors within the area directly connected with the exploitation, in which the seismic activity induced by this exploitation occurs. The estimation of the parameters of the determined model should each time be carried out with investigations of the correctness of the model. The method cannot be applied when the number of recorded phenomena is small and when there is insufficient data to make it possible to calculate the index Pw.
文摘The flow resistance of stent with different shapes of wire cross-section can be considered as a factor that influences the condition of inflow and outflow through the stent wire. Different from the traditional stents, a novel stent with triangular wire cross-section was proposed, and numerical simulations were performed to compare the hemodynamic effect of the novel stent with that of traditional ones. Three constructed aneurysm models were treated with a different kin^l of stent separately, including one with bare circular wire cross-section stent （named CM）, one with bare rectangular wire cross-section stent （named RM）, one with bare triangular cross-section stent （named TM）. An unstented aneurysm model was also constructed to serve as a control （named UM）. Numerical simulations of the fluid-structure interaction in these four models were performed under the same boundary conditions using finite element method. The simulation results demonstrated the resistance of the novel stent is lower than RM stent, but higher than that of CM stent. TM stent attributes a higher velocity decreasing and a longer turnover time compared with CM stent. The distribution of wall shear stress indicated the possibility of aneurysm development along the distal wall was higher than the proximal wall, and the top of aneurysm was in the highest risk of rupture.
文摘The traditional Contour Tracing algorithm works on the binary image. It is developed that a new model called Facula Diffusion which can work directly on gray-scaled images according to the principle of human vision. The diffusion operation is controlled by four factors including approximation, closing, length-limiting, and hit-rate. Based on this model, three shape indices, i. e., dimension index, abnormity index, and fluctuation index, were put forward to describe the shape of objects. The rule of shape indices selection was discussed subsequently. Finally, the fibers in polyester/cotton blended yam are classified and the blending ratio is determined.
基金supported by the Project 42374170,XDA0430101.and 2022YFF0706200.
文摘Landslides are a type of natural disaster that can cause substantial harm to humanity.Monitoring and predicting the initiation of potential landslides is critical to avoiding losses due to disasters and economic activities.The impact of the controlled-source audio-frequency magnetotelluric method on investigating landslide surfaces is assessed through numerical simulations with a finite element approach.A Dirichlet boundary condition is selected to match the truncated boundary,resulting in a remarkable improvement in simulation effi ciency.Rederivation of the formulas for a layered medium adept to the controlled-source audiofrequency magnetotelluric method is necessary to determine the electromagnetic fi eld at any location along the truncated boundary.After the reliability evaluation of the new codes,a landslide model with a slide surface is designed,and the characteristics of its electromagnetic fi eld and the apparent resistivity are studied.Instead of the total electromagnetic fi eld,which is strongly infl uenced by topography variation,the apparent resistivity should be used for sliding surface detection.The normalized pure anomalous electromagnetic fi eld may also be employed to quickly assess the detectability of the sliding surface.Overall,this study demonstrates that the controlled-source audio-frequency magnetotelluric method can be employed for investigating landslides,and recommends survey parameters,including confi guration,frequency range,and length of survey line in landslide exploration.
基金Supported by the Scientific Research Key Project of the Education Department of Henan under Grant Nos.13A140113 and 12A140011Zhoukou Shizhuan Boshi Chuangxin under Grant No.20121039
文摘Abstract In the context of the left-right twin Higgs （LRTH） model, we have studied the charged Higgs bosons production processes e＋e-（γγ） →tbФ- at the International Linear Collider （ILC）. It is found that the cross sections of these two processes could reach a few Fo with reasonable parameter values. With the yearly integrated luminosity of L 500 fb-1 expected at the ILC, one could collect hundreds up to thousands of charged ttiggs events via these two processes. Therefore, our researches in this paper can help us search for charged Higgs bosons, and furthermore, to test the LRTH model.
