This paper describes the design,characterization and fabrication of a planar In0.53Ga0.47As based planar Gunn diode on an In P semi-insulating substrate.The planar Gunn diode was designed in Coplanar Waveguide(CPW)for...This paper describes the design,characterization and fabrication of a planar In0.53Ga0.47As based planar Gunn diode on an In P semi-insulating substrate.The planar Gunn diode was designed in Coplanar Waveguide(CPW)format with an active channel length and width of 4μm and 120μm respectively,and modeled using the Advanced Design System(ADS-2009)simulation package.The initial experimental measurements have given a fundamental oscillation frequency of 63.5 GHz with a RF output power of-6.6 d Bm,which is the highest recorded power for an In P based planar Gunn diode.展开更多
In order to investigate the tensile bond anchorage properties of Australian 500N steel bars in concrete, 111 pullout tests were conducted. The precise bond slip values have been gained by using the laser displacement ...In order to investigate the tensile bond anchorage properties of Australian 500N steel bars in concrete, 111 pullout tests were conducted. The precise bond slip values have been gained by using the laser displacement sensor with high resolution, including the complete bond-slip curves. How the main anchorage factors such as concrete strength, bar diameter （8, I0, 12, 16, 20, 24, 28, 32 and 36 mm） the concrete covered, embedded length and transverse reinforcement influencing the bond anchorage properties was studied under tensile condition. The process of the tensile force-slip failure for Australian 500N reinforcing steel can be divided into five stages： elastic stage, local slip stage, slip in ascent stage, slip in descent stage and remnant stage. The formula for calculating the tensile bond strength of Australian 500N reinforcing bar in concrete was proposed according to the test results, including the consistent model for tensile bond-slip relationship.展开更多
We present an improved hybrid genetic algorithm to solve the two-dimensional Eucli-dean traveling salesman problem (TSP), in which the crossover operator is enhanced with a local search. The proposed algorithm is expe...We present an improved hybrid genetic algorithm to solve the two-dimensional Eucli-dean traveling salesman problem (TSP), in which the crossover operator is enhanced with a local search. The proposed algorithm is expected to obtain higher quality solutions within a reasonable computational time for TSP by perfectly integrating GA and the local search. The elitist choice strategy, the local search crossover operator and the double-bridge random mutation are highlighted, to enhance the convergence and the possibility of escaping from the local optima. The experimental results illustrate that the novel hybrid genetic algorithm outperforms other genetic algorithms by providing higher accuracy and satisfactory efficiency in real optimization processing.展开更多
In this study, the breakup of a melt jet into a viscous medium is investigated in the presence of an intense electric field. Fragmentation of the melt jet occurs due to both hydrodynamic and electrohydrodynamic （EHD...In this study, the breakup of a melt jet into a viscous medium is investigated in the presence of an intense electric field. Fragmentation of the melt jet occurs due to both hydrodynamic and electrohydrodynamic （EHD） forces within two kinds of silicone oil of different viscosities. The size and shape characteristics of the produced particles have been studied using SEM images, and the particle size distributions were found to exhibit considerable variations when a voltage was applied and when both the viscosity and temperature of the base fluid were changed. The morphologies of the particles were also affected by the same parameters. For instance, by applying EHD force, significant enhancements in size reduction and increased roundness of the particles occurred. The breakup process of the melt jet was found to be dominant by hydrodynamic or electrohydrodynamic instabilities, depending on the situation. Governing mechanisms （instability） in the cases of pure hydrodynamic and electrohydrodynamic fragmentations are discussed.展开更多
Recently,initiatives to integrate Internet of Things(IoT)technologies into smart buildings have attracted extensive attention for improving the performance of buildings and the comfort of occupants.However,the amount ...Recently,initiatives to integrate Internet of Things(IoT)technologies into smart buildings have attracted extensive attention for improving the performance of buildings and the comfort of occupants.However,the amount of data generated by IoT devices remains a challenge to the building management systems(BMSs)in terms of intensity and complexity.Different from cloud computing and edge computing,we propose a computation sharing architecture in smart buildings to incentivize idle computing devices(ICDs,sellers)to offload computational tasks for the BMS(buyer).In this paper,we design a hierarchical game model,consisting of a Stackelberg game and a Cournot game,to achieve a dynamic increase in computational capacity for the BMS.To guarantee the utility of BMS and ICDs,the Stackelberg game model is built to analyze the interactions between BMS and ICDs.Then,the Cournot game model is presented to formulate the internal competition among multiple ICDs.Under the premise of the subgame perfect Nash equilibrium,the BMS can quote the optimal pricing strategy,and the ICDs can share the corresponding optimal amount of computing resources.Finally,the simulation results show that the BMS’s computational capacity is enhanced on-demand,and each participant in the game obtains maximal utility.展开更多
The accuracy and efficiency of a class of finite volume methods are investigated for numerical solution of morphodynamic problems in one space dimension.The governing equations consist of two components,namely a hydra...The accuracy and efficiency of a class of finite volume methods are investigated for numerical solution of morphodynamic problems in one space dimension.The governing equations consist of two components,namely a hydraulic part described by the shallow water equations and a sediment part described by the Exner equation.Based on different formulations of the morphodynamic equations,we propose a family of three finite volume methods.The numerical fluxes are reconstructed using a modified Roe’s scheme that incorporates,in its reconstruction,the sign of the Jacobian matrix in the morphodynamic system.A well-balanced discretization is used for the treatment of the source terms.The method is wellbalanced,non-oscillatory and suitable for both slow and rapid interactions between hydraulic flow and sediment transport.The obtained results for several morphodynamic problems are considered to be representative,and might be helpful for a fair rating of finite volume solution schemes,particularly in long time computations.展开更多
In direct volume rendering(DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. This paper...In direct volume rendering(DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. This paper presents the results of a subjective experiment where participants stereoscopically viewed DVR rendered scenes and rated their subjective quality.The statistical analysis of the results focuses on the relationship between the quality of the stereoscopic scene and properties of the filters such as post-aliasing and smoothing, as well as the relationship between the quality of the stereoscopic scene and properties of the rendered images such as shape compactness.The experiment evaluated five reconstruction filters on four different volumetric datasets. Participants rated the stereoscopic scenes on four quality measures:depth quality, depth layout, lack of jaggyness, and sharpness. The results show that the correlation between the quality measures and post-aliasing and smoothing, which are properties associated with each reconstruction filter, is moderate and statistically insignificant. On the other hand, the correlation between the quality measures and compactness, which is a property specific to each rendered image, is strong and statistically significant.展开更多
In this article we consider the application of Schwarz-type domain decomposition preconditioners to the discontinuous Galerkin finite element approximation of the compressible Navier-Stokes equations.To discretize thi...In this article we consider the application of Schwarz-type domain decomposition preconditioners to the discontinuous Galerkin finite element approximation of the compressible Navier-Stokes equations.To discretize this system of conservation laws,we exploit the(adjoint consistent)symmetric version of the interior penalty discontinuous Galerkin finite element method.To define the necessary coarse-level solver required for the definition of the proposed preconditioner,we exploit ideas from composite finite element methods,which allow for the definition of finite element schemes on general meshes consisting of polygonal(agglomerated)elements.The practical performance of the proposed preconditioner is demonstrated for a series of viscous test cases in both two-and three-dimensions.展开更多
There is increasing interest in the use of earthen construction materials,such as rammed earth,due to their inherent sustainability.These materials have been used by man for thousands of years and some of the earliest...There is increasing interest in the use of earthen construction materials,such as rammed earth,due to their inherent sustainability.These materials have been used by man for thousands of years and some of the earliest examples can be found in China.Features of the structures of these materials arise from the means of production.In particular,in situ earthen construction materials exhibit strong anisotropy due to their layered nature.A more subtle structure effect arises from the way that the earth mixture is deposited.This paper reviews and discusses stratification effects in dry soil mixtures,including some original experimental work,and indicates some links between the features of the dry mixtures and earthen construction materials.Improved understanding of the physical processes in play will allow more accurate specification of these materials in the future,and hence spread their use.展开更多
基金supported by ESPRC through EP/H011862/1,and EP/H012966/1
文摘This paper describes the design,characterization and fabrication of a planar In0.53Ga0.47As based planar Gunn diode on an In P semi-insulating substrate.The planar Gunn diode was designed in Coplanar Waveguide(CPW)format with an active channel length and width of 4μm and 120μm respectively,and modeled using the Advanced Design System(ADS-2009)simulation package.The initial experimental measurements have given a fundamental oscillation frequency of 63.5 GHz with a RF output power of-6.6 d Bm,which is the highest recorded power for an In P based planar Gunn diode.
基金Project(DP0988940) supported by Australian Research Council Discovery Grant Program Project(2011M500930) supported by Postdoctoral Science Foundation of China+1 种基金Project(11KJB560003) supported by College Natural Science Foundation of Jiangsu Province,ChinaProject(163050072) supported by the Talent Introduction Foundation of Nanjing Forestry University,China
文摘In order to investigate the tensile bond anchorage properties of Australian 500N steel bars in concrete, 111 pullout tests were conducted. The precise bond slip values have been gained by using the laser displacement sensor with high resolution, including the complete bond-slip curves. How the main anchorage factors such as concrete strength, bar diameter （8, I0, 12, 16, 20, 24, 28, 32 and 36 mm） the concrete covered, embedded length and transverse reinforcement influencing the bond anchorage properties was studied under tensile condition. The process of the tensile force-slip failure for Australian 500N reinforcing steel can be divided into five stages： elastic stage, local slip stage, slip in ascent stage, slip in descent stage and remnant stage. The formula for calculating the tensile bond strength of Australian 500N reinforcing bar in concrete was proposed according to the test results, including the consistent model for tensile bond-slip relationship.
文摘We present an improved hybrid genetic algorithm to solve the two-dimensional Eucli-dean traveling salesman problem (TSP), in which the crossover operator is enhanced with a local search. The proposed algorithm is expected to obtain higher quality solutions within a reasonable computational time for TSP by perfectly integrating GA and the local search. The elitist choice strategy, the local search crossover operator and the double-bridge random mutation are highlighted, to enhance the convergence and the possibility of escaping from the local optima. The experimental results illustrate that the novel hybrid genetic algorithm outperforms other genetic algorithms by providing higher accuracy and satisfactory efficiency in real optimization processing.
文摘In this study, the breakup of a melt jet into a viscous medium is investigated in the presence of an intense electric field. Fragmentation of the melt jet occurs due to both hydrodynamic and electrohydrodynamic （EHD） forces within two kinds of silicone oil of different viscosities. The size and shape characteristics of the produced particles have been studied using SEM images, and the particle size distributions were found to exhibit considerable variations when a voltage was applied and when both the viscosity and temperature of the base fluid were changed. The morphologies of the particles were also affected by the same parameters. For instance, by applying EHD force, significant enhancements in size reduction and increased roundness of the particles occurred. The breakup process of the melt jet was found to be dominant by hydrodynamic or electrohydrodynamic instabilities, depending on the situation. Governing mechanisms （instability） in the cases of pure hydrodynamic and electrohydrodynamic fragmentations are discussed.
基金in part by the Natural Science Foundation of China under Grant 61871446,61801238the Postgraduate Research&Practice Innovation Program of Jiangsu Province under Grant KYCX18_0887the Natural Science Foundation of Jiangsu Province under Grant BK20170758.
文摘Recently,initiatives to integrate Internet of Things(IoT)technologies into smart buildings have attracted extensive attention for improving the performance of buildings and the comfort of occupants.However,the amount of data generated by IoT devices remains a challenge to the building management systems(BMSs)in terms of intensity and complexity.Different from cloud computing and edge computing,we propose a computation sharing architecture in smart buildings to incentivize idle computing devices(ICDs,sellers)to offload computational tasks for the BMS(buyer).In this paper,we design a hierarchical game model,consisting of a Stackelberg game and a Cournot game,to achieve a dynamic increase in computational capacity for the BMS.To guarantee the utility of BMS and ICDs,the Stackelberg game model is built to analyze the interactions between BMS and ICDs.Then,the Cournot game model is presented to formulate the internal competition among multiple ICDs.Under the premise of the subgame perfect Nash equilibrium,the BMS can quote the optimal pricing strategy,and the ICDs can share the corresponding optimal amount of computing resources.Finally,the simulation results show that the BMS’s computational capacity is enhanced on-demand,and each participant in the game obtains maximal utility.
基金This work was partly performed while the third author was a visiting professor at CMLA,Ecole normale superieure de Cachan.Financial support provided by CLMA,ENS Cachan is gratefully acknowledged。
文摘The accuracy and efficiency of a class of finite volume methods are investigated for numerical solution of morphodynamic problems in one space dimension.The governing equations consist of two components,namely a hydraulic part described by the shallow water equations and a sediment part described by the Exner equation.Based on different formulations of the morphodynamic equations,we propose a family of three finite volume methods.The numerical fluxes are reconstructed using a modified Roe’s scheme that incorporates,in its reconstruction,the sign of the Jacobian matrix in the morphodynamic system.A well-balanced discretization is used for the treatment of the source terms.The method is wellbalanced,non-oscillatory and suitable for both slow and rapid interactions between hydraulic flow and sediment transport.The obtained results for several morphodynamic problems are considered to be representative,and might be helpful for a fair rating of finite volume solution schemes,particularly in long time computations.
文摘In direct volume rendering(DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. This paper presents the results of a subjective experiment where participants stereoscopically viewed DVR rendered scenes and rated their subjective quality.The statistical analysis of the results focuses on the relationship between the quality of the stereoscopic scene and properties of the filters such as post-aliasing and smoothing, as well as the relationship between the quality of the stereoscopic scene and properties of the rendered images such as shape compactness.The experiment evaluated five reconstruction filters on four different volumetric datasets. Participants rated the stereoscopic scenes on four quality measures:depth quality, depth layout, lack of jaggyness, and sharpness. The results show that the correlation between the quality measures and post-aliasing and smoothing, which are properties associated with each reconstruction filter, is moderate and statistically insignificant. On the other hand, the correlation between the quality measures and compactness, which is a property specific to each rendered image, is strong and statistically significant.
基金S.Giani and P.Houston acknowledge the financial support of the EPSRC under the grant EP/H005498.PH also acknowledges the support of the Leverhulme Trust.
文摘In this article we consider the application of Schwarz-type domain decomposition preconditioners to the discontinuous Galerkin finite element approximation of the compressible Navier-Stokes equations.To discretize this system of conservation laws,we exploit the(adjoint consistent)symmetric version of the interior penalty discontinuous Galerkin finite element method.To define the necessary coarse-level solver required for the definition of the proposed preconditioner,we exploit ideas from composite finite element methods,which allow for the definition of finite element schemes on general meshes consisting of polygonal(agglomerated)elements.The practical performance of the proposed preconditioner is demonstrated for a series of viscous test cases in both two-and three-dimensions.
基金funded by a studentship awarded by the School of Engineering and Computing Sciences,Durham University.
文摘There is increasing interest in the use of earthen construction materials,such as rammed earth,due to their inherent sustainability.These materials have been used by man for thousands of years and some of the earliest examples can be found in China.Features of the structures of these materials arise from the means of production.In particular,in situ earthen construction materials exhibit strong anisotropy due to their layered nature.A more subtle structure effect arises from the way that the earth mixture is deposited.This paper reviews and discusses stratification effects in dry soil mixtures,including some original experimental work,and indicates some links between the features of the dry mixtures and earthen construction materials.Improved understanding of the physical processes in play will allow more accurate specification of these materials in the future,and hence spread their use.
