A more natural way for non-expert users to express their tasks in an open-ended set is to use natural language. In this case,a human-centered intelligent agent/robot is required to be able to understand and generate p...A more natural way for non-expert users to express their tasks in an open-ended set is to use natural language. In this case,a human-centered intelligent agent/robot is required to be able to understand and generate plans for these naturally expressed tasks. For this purpose, it is a good way to enhance intelligent robot's abilities by utilizing open knowledge extracted from the web, instead of hand-coded knowledge. A key challenge of utilizing open knowledge lies in the semantic interpretation of the open knowledge organized in multiple modes, which can be unstructured or semi-structured, before one can use it.Previous approaches used a limited lexicon to employ combinatory categorial grammar(CCG) as the underlying formalism for semantic parsing over sentences. Here, we propose a more effective learning method to interpret semi-structured user instructions. Moreover, we present a new heuristic method to recover missing semantic information from the context of an instruction. Experiments showed that the proposed approach renders significant performance improvement compared to the baseline methods and the recovering method is promising.展开更多
Fast and accurate prediction of sound radiation of Contra-Rotating Open Rotors(CRORs)is an essential element of design methods of low-noise open rotor propulsion systems.In the present work,a previous frequency-domain...Fast and accurate prediction of sound radiation of Contra-Rotating Open Rotors(CRORs)is an essential element of design methods of low-noise open rotor propulsion systems.In the present work,a previous frequency-domain model is extended to predict CROR noise.It builds explicitly the relationship between harmonic loadings and corresponding tonal noise,by which the influential parameters to noise generation can be clearly understood.The real distribu-tions of steady and unsteady blade loadings are calculated by the Nonlinear Harmonic(NLH)method.In the present hybrid approach,both the CFD and acoustic modules are solved in the fre-quency domain.To assess the accuracy of the developed method,the loading noise of a CROR is calculated and compared against results by using the time-domain FW-H module of NUMECA.The predicted sound directivities by the two methods are in good agreements.The present acoustic model in the frequency domain is proven to be accurate and have high efficiency in far-field noise prediction and data processing.Furthermore,the characteristics of the CROR interaction tonal noise are analyzed and discussed.展开更多
The effect of open porosity of Y2O3ceramic on the apparent contact angle and interaction between molten Ti47 Al alloy and Y2O3ceramic substrates under pure Ar was investigated by using a sessile drop method at 1600 &#...The effect of open porosity of Y2O3ceramic on the apparent contact angle and interaction between molten Ti47 Al alloy and Y2O3ceramic substrates under pure Ar was investigated by using a sessile drop method at 1600 °C. As the open porosity increased from 9.6% to 30.3%, the spreading rate of molten Ti47 Al alloys on Y2O3ceramic substrates reduced from 2.3 to 1.1°/s; meanwhile, the final equilibrium contact angles increased from 55.8° to 63.6°. The microstructure observations revealed that with increasing the open porosity of the Y2O3substrates, the thickness of sand adhesion at the interfaces of the alloy droplets increased from 5.4 to 15.7 lm, and ceramic particles in the alloy matrix increased as well. The increasing contact area between the molten alloy and the substrate played a dominant role in determining the interaction on Ti Al/Y2O3interface.展开更多
The effects of the Dzyaloshinskii Moriya （DM） and the Kaplan-Shekhtman-Entinwohlman-Aharony （KSEA） superexchange interactions on the ground state properties of the one-dimensional spin-Peilers system in open chain...The effects of the Dzyaloshinskii Moriya （DM） and the Kaplan-Shekhtman-Entinwohlman-Aharony （KSEA） superexchange interactions on the ground state properties of the one-dimensional spin-Peilers system in open chain are studied by using the Lanczos numerical method. The study concentrates mainly on the influence of systemic dimerisation in open chain. The results show that systemic ground state energy density varies with dimerisation parameter 5 in different DM interactions, and there exists a special point 5c where the DM interaction has no influence on the systemic dimerisation, no matter whether the DM interaction is relative or irrelative to systemic dimerisation （η= 1 or η=0）. The KSEA interaction has no fixed special point, but the points of intersection are dense relatively in a certain numberical value range, and sparse in other numberical value ranges. So we can conclude that the antisymmetric anisotropy DM interaction differs from the symmetric anisotropy KSEA interaction, but they are analogous in the sense of the influence of systemic dimerisation in open chain.展开更多
A direct numerical modeling method for parachute is proposed firstly, and a model for the star-shaped folded parachute with detailed structures is established. The simplified arbitrary Lagrangian-Eulerian fluid struct...A direct numerical modeling method for parachute is proposed firstly, and a model for the star-shaped folded parachute with detailed structures is established. The simplified arbitrary Lagrangian-Eulerian fluid structure interaction （SALE/FSI） method is used to simulate the infla- tion process of a folded parachute, and the flow field calculation is mainly based on operator split- ting technique. By using this method, the dynamic variations of related parameters such as flow field and structure are obtained, and the load jump appearing at the end of initial inflation stage is cap- tured. Numerical results including opening load, drag characteristics, swinging angle, etc. are well consistent with wind tunnel tests. In addition, this coupled method can get more space-time detailed information such as geometry shape, structure, motion, and flow field. Compared with previous inflation time method, this method is a completely theoretical analysis approach without relying on empirical coefficients, which can provide a reference for material selection, performance optimi- zation during parachute design.展开更多
The inflation of a five-ring cone parachute with the airflow velocity of 18 m/s is studied based on the simplified arbitrary Lagrange Euler （SALE）/fluid-structure interaction （FSI） method. The numerical results of...The inflation of a five-ring cone parachute with the airflow velocity of 18 m/s is studied based on the simplified arbitrary Lagrange Euler （SALE）/fluid-structure interaction （FSI） method. The numerical results of the canopy shape, stability, opening load, and drag area are obtained, and they are well consistent with the experimental data gained from wind tunnel tests. The method is then used to simulate the opening process under different velocities. It is found that the first load shock affected by the velocity often occurs at the end of the initial inflation stage. For the first time, the phenomena that the inflation distance proportion coefficient increases and the dynamic load coefficient decreases, respectively, with the increase in the velocity are revealed. The above proposed method is competent to solve the large deformation problem without empirial coefficients, and can collect more space-time details of fluid-structure-motion information when it is compared with the traditional method.展开更多
The present study theoretically as well as experimentally investigates the interaction between waves and an array of porous circular cylinders with or without an inner porous plate based on the linear wave theory. To ...The present study theoretically as well as experimentally investigates the interaction between waves and an array of porous circular cylinders with or without an inner porous plate based on the linear wave theory. To design more effective floating breakwaters, the transmission rate of waves propagating through the array is evaluated. Each cylinder in the array is partly made of porous materials. Specifically, it possesses a porous sidewall and an impermeable bottom. In addition, an inner porous plate is horizontally fixed inside the cylinders. It dissipates the wave more effectively and eliminates the sloshing phenomenon. The approach suggested by Kagemoto and Yue （1986） is adopted to solve the multiple-scatter problem, while a hierarchical interaction theory is adopted to deal with hydrodynamic interactions among a great number of bodies, which efficiently saves computation time. Meanwhile, a series of model tests with an array of porous cylinders is performed in a wave basin to validate the theoretical work and the calculated results. The draft of the cylinders, the location of the inner porous plate, and the spacing between adjacent cylinders are also adjusted to investigate their effects on wave dissipation.展开更多
We investigate the integrability of the Rabi model,which is traditionally viewed as not Yang–Baxter-integrable despite its solvability.Building on efforts by Bogoliubov and Kulish(2013 J.Math.Sci.19214–30),Amico et ...We investigate the integrability of the Rabi model,which is traditionally viewed as not Yang–Baxter-integrable despite its solvability.Building on efforts by Bogoliubov and Kulish(2013 J.Math.Sci.19214–30),Amico et al(2007 Nucl.Phys.B 787283–300),and Batchelor and Zhou(2015 Phys.Rev.A 91053808),who explored special limiting cases of the model,we develop a spin–boson interaction Hamiltonian under more general boundary conditions,particularly focusing on open boundary conditions with off-diagonal terms.Our approach maintains the direction of the spin in the z direction and also preserves the boson particle number operator a^(†)a,marking a progression beyond previous efforts that have primarily explored reduced forms of the Rabi model from Yang–Baxter algebra.We also address the presence of‘unwanted’quadratic boson terms a^(2) and a^(†2),which share coefficients with the boson particle number operator.Interestingly,these terms vanish when spectral parameter u=±θ_(s),simplifying the model to a limiting case of operator-valued twists,a scenario previously discussed by Batchelor and Zhou(2015 Phys.Rev.A 91053808).展开更多
Underground mining is an economically viable option for exploiting ore reserves deemed uneconomic after open pit mining. However, underground development can have adverse effects on the above existing open pit slope w...Underground mining is an economically viable option for exploiting ore reserves deemed uneconomic after open pit mining. However, underground development can have adverse effects on the above existing open pit slope walls. As a goal of this paper, identification and assessment of potential slope instabilities prior to underground development is crucial for safe and sustainable mining. Towards goal achieving, this paper gives a comprehensive parametric study to investigate the influence of sublevel open stope (SLOS) underground mining on the surface and open pit slope walls. By means of numerical simulation, the SLOS design is tried against the existing open pit followed by adjustments of important slope parameters which are overall slope height (OSH) and overall slope angle (OSA). We found that underground mining may induce slope failure, particularly on the hangingwall side of the pit. Subsidence is prominent on the hanging wall and the surface, whereas, the uplift dominates the footwall and pit bottom. Pit wall closure is observed during underground mining. Although the assigned dimensions in the parametric study show a negligible effect of OSH and OSA, the high OSH experience low subsidence in comparison with low OSH. Overall, the results demonstrate that the slope walls on the hanging wall side are mostly affected by the underground mining and high-stress concentration prevails near slope toes and pit bottom. Additionally, slope deformation decrease from pit bottom towards the slope crest and surface. The results of this study add knowledge to open pit and underground mining interaction.展开更多
Effects of two important factors on earthquake response of high arch dams are considered and combined into one program.These tactors are:effects of radiation damping of the infinite canyon and local non-linearity of t...Effects of two important factors on earthquake response of high arch dams are considered and combined into one program.These tactors are:effects of radiation damping of the infinite canyon and local non-linearity of the contraction joint opening between the dam monoliths.For modeling of rock canyon,the discrete parameters are obtained based on a curve fitting, thus allowing the nonlinear dam system to be solved in the time domain.The earthquake uniform tree-field input at the dam-canyon interface is used.An engineering example is given to demonstrate the significant effects of the radiation damping on the structure response.展开更多
This research describes a quantitative,rapid,and low-cost methodology for debris flow susceptibility evaluation at the basin scale using open-access data and geodatabases.The proposed approach can aid decision makers ...This research describes a quantitative,rapid,and low-cost methodology for debris flow susceptibility evaluation at the basin scale using open-access data and geodatabases.The proposed approach can aid decision makers in land management and territorial planning,by first screening for areas with a higher debris flow susceptibility.Five environmental predisposing factors,namely,bedrock lithology,fracture network,quaternary deposits,slope inclination,and hydrographic network,were selected as independent parameters and their mutual interactions were described and quantified using the Rock Engineering System(RES)methodology.For each parameter,specific indexes were proposed,aiming to provide a final synthetic and representative index of debris flow susceptibility at the basin scale.The methodology was tested in four basins located in the Upper Susa Valley(NW Italian Alps)where debris flow events are the predominant natural hazard.The proposed matrix can represent a useful standardized tool,universally applicable,since it is independent of type and characteristic of the basin.展开更多
基金supported by the National Natural Science Foundation of China(61175057)the USTC Key-Direction Research Fund(WK0110000028)
文摘A more natural way for non-expert users to express their tasks in an open-ended set is to use natural language. In this case,a human-centered intelligent agent/robot is required to be able to understand and generate plans for these naturally expressed tasks. For this purpose, it is a good way to enhance intelligent robot's abilities by utilizing open knowledge extracted from the web, instead of hand-coded knowledge. A key challenge of utilizing open knowledge lies in the semantic interpretation of the open knowledge organized in multiple modes, which can be unstructured or semi-structured, before one can use it.Previous approaches used a limited lexicon to employ combinatory categorial grammar(CCG) as the underlying formalism for semantic parsing over sentences. Here, we propose a more effective learning method to interpret semi-structured user instructions. Moreover, we present a new heuristic method to recover missing semantic information from the context of an instruction. Experiments showed that the proposed approach renders significant performance improvement compared to the baseline methods and the recovering method is promising.
基金co-supported by the National Natural Science Foundation of China(Nos.52022009,51790514)the National Science and Technology Major Project,China(No.2017-II-003-0015)the Key Laboratory Foundation,China(No.2021-JCJQ-LB-062-0102).
文摘Fast and accurate prediction of sound radiation of Contra-Rotating Open Rotors(CRORs)is an essential element of design methods of low-noise open rotor propulsion systems.In the present work,a previous frequency-domain model is extended to predict CROR noise.It builds explicitly the relationship between harmonic loadings and corresponding tonal noise,by which the influential parameters to noise generation can be clearly understood.The real distribu-tions of steady and unsteady blade loadings are calculated by the Nonlinear Harmonic(NLH)method.In the present hybrid approach,both the CFD and acoustic modules are solved in the fre-quency domain.To assess the accuracy of the developed method,the loading noise of a CROR is calculated and compared against results by using the time-domain FW-H module of NUMECA.The predicted sound directivities by the two methods are in good agreements.The present acoustic model in the frequency domain is proven to be accurate and have high efficiency in far-field noise prediction and data processing.Furthermore,the characteristics of the CROR interaction tonal noise are analyzed and discussed.
基金support of the‘‘National Science&Technology Pillar Program of China’’project of PR China(No.2013BAB11B04)the National Natural Science Foundation of China(Grant No.51404017)the State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technolog
文摘The effect of open porosity of Y2O3ceramic on the apparent contact angle and interaction between molten Ti47 Al alloy and Y2O3ceramic substrates under pure Ar was investigated by using a sessile drop method at 1600 °C. As the open porosity increased from 9.6% to 30.3%, the spreading rate of molten Ti47 Al alloys on Y2O3ceramic substrates reduced from 2.3 to 1.1°/s; meanwhile, the final equilibrium contact angles increased from 55.8° to 63.6°. The microstructure observations revealed that with increasing the open porosity of the Y2O3substrates, the thickness of sand adhesion at the interfaces of the alloy droplets increased from 5.4 to 15.7 lm, and ceramic particles in the alloy matrix increased as well. The increasing contact area between the molten alloy and the substrate played a dominant role in determining the interaction on Ti Al/Y2O3interface.
基金Project supported by the Natural Science Research Key Program of Higher Education Institution of Anhui Province,China (Grant No. KJ2010A335)the Youth Science Research Program of Anhui University of Technology,China (Grant No. QZ200824)
文摘The effects of the Dzyaloshinskii Moriya （DM） and the Kaplan-Shekhtman-Entinwohlman-Aharony （KSEA） superexchange interactions on the ground state properties of the one-dimensional spin-Peilers system in open chain are studied by using the Lanczos numerical method. The study concentrates mainly on the influence of systemic dimerisation in open chain. The results show that systemic ground state energy density varies with dimerisation parameter 5 in different DM interactions, and there exists a special point 5c where the DM interaction has no influence on the systemic dimerisation, no matter whether the DM interaction is relative or irrelative to systemic dimerisation （η= 1 or η=0）. The KSEA interaction has no fixed special point, but the points of intersection are dense relatively in a certain numberical value range, and sparse in other numberical value ranges. So we can conclude that the antisymmetric anisotropy DM interaction differs from the symmetric anisotropy KSEA interaction, but they are analogous in the sense of the influence of systemic dimerisation in open chain.
基金co-supported by the National Natural Science Foundation of China (No. 11172137)the Aeronautical Science Foundation of China (No. 20122910001)
文摘A direct numerical modeling method for parachute is proposed firstly, and a model for the star-shaped folded parachute with detailed structures is established. The simplified arbitrary Lagrangian-Eulerian fluid structure interaction （SALE/FSI） method is used to simulate the infla- tion process of a folded parachute, and the flow field calculation is mainly based on operator split- ting technique. By using this method, the dynamic variations of related parameters such as flow field and structure are obtained, and the load jump appearing at the end of initial inflation stage is cap- tured. Numerical results including opening load, drag characteristics, swinging angle, etc. are well consistent with wind tunnel tests. In addition, this coupled method can get more space-time detailed information such as geometry shape, structure, motion, and flow field. Compared with previous inflation time method, this method is a completely theoretical analysis approach without relying on empirical coefficients, which can provide a reference for material selection, performance optimi- zation during parachute design.
基金supported by the National Natural Science Foundation of China(No.11172137)the Aeronautical Science Foundation of China(No.20122910001)
文摘The inflation of a five-ring cone parachute with the airflow velocity of 18 m/s is studied based on the simplified arbitrary Lagrange Euler （SALE）/fluid-structure interaction （FSI） method. The numerical results of the canopy shape, stability, opening load, and drag area are obtained, and they are well consistent with the experimental data gained from wind tunnel tests. The method is then used to simulate the opening process under different velocities. It is found that the first load shock affected by the velocity often occurs at the end of the initial inflation stage. For the first time, the phenomena that the inflation distance proportion coefficient increases and the dynamic load coefficient decreases, respectively, with the increase in the velocity are revealed. The above proposed method is competent to solve the large deformation problem without empirial coefficients, and can collect more space-time details of fluid-structure-motion information when it is compared with the traditional method.
基金supported by the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China (Grant Nos. 40876049 and 31172446)+1 种基金the Science and Technology Department of Zhejiang Province(Grant No. 2008C12065-1)the Teaching Department of Zhejiang Province (Grant No. Z200803912)
文摘The present study theoretically as well as experimentally investigates the interaction between waves and an array of porous circular cylinders with or without an inner porous plate based on the linear wave theory. To design more effective floating breakwaters, the transmission rate of waves propagating through the array is evaluated. Each cylinder in the array is partly made of porous materials. Specifically, it possesses a porous sidewall and an impermeable bottom. In addition, an inner porous plate is horizontally fixed inside the cylinders. It dissipates the wave more effectively and eliminates the sloshing phenomenon. The approach suggested by Kagemoto and Yue （1986） is adopted to solve the multiple-scatter problem, while a hierarchical interaction theory is adopted to deal with hydrodynamic interactions among a great number of bodies, which efficiently saves computation time. Meanwhile, a series of model tests with an array of porous cylinders is performed in a wave basin to validate the theoretical work and the calculated results. The draft of the cylinders, the location of the inner porous plate, and the spacing between adjacent cylinders are also adjusted to investigate their effects on wave dissipation.
基金supported by the National Natural Science Foundation of China(Grant Nos.12275214,12247103,12047502)the Natural Science Basic Research Program of Shaanxi Province Grant Nos.2021JCW-19 and 2019JQ-107Shaanxi Key Laboratory for Theoretical Physics Frontiers in China.
文摘We investigate the integrability of the Rabi model,which is traditionally viewed as not Yang–Baxter-integrable despite its solvability.Building on efforts by Bogoliubov and Kulish(2013 J.Math.Sci.19214–30),Amico et al(2007 Nucl.Phys.B 787283–300),and Batchelor and Zhou(2015 Phys.Rev.A 91053808),who explored special limiting cases of the model,we develop a spin–boson interaction Hamiltonian under more general boundary conditions,particularly focusing on open boundary conditions with off-diagonal terms.Our approach maintains the direction of the spin in the z direction and also preserves the boson particle number operator a^(†)a,marking a progression beyond previous efforts that have primarily explored reduced forms of the Rabi model from Yang–Baxter algebra.We also address the presence of‘unwanted’quadratic boson terms a^(2) and a^(†2),which share coefficients with the boson particle number operator.Interestingly,these terms vanish when spectral parameter u=±θ_(s),simplifying the model to a limiting case of operator-valued twists,a scenario previously discussed by Batchelor and Zhou(2015 Phys.Rev.A 91053808).
文摘Underground mining is an economically viable option for exploiting ore reserves deemed uneconomic after open pit mining. However, underground development can have adverse effects on the above existing open pit slope walls. As a goal of this paper, identification and assessment of potential slope instabilities prior to underground development is crucial for safe and sustainable mining. Towards goal achieving, this paper gives a comprehensive parametric study to investigate the influence of sublevel open stope (SLOS) underground mining on the surface and open pit slope walls. By means of numerical simulation, the SLOS design is tried against the existing open pit followed by adjustments of important slope parameters which are overall slope height (OSH) and overall slope angle (OSA). We found that underground mining may induce slope failure, particularly on the hangingwall side of the pit. Subsidence is prominent on the hanging wall and the surface, whereas, the uplift dominates the footwall and pit bottom. Pit wall closure is observed during underground mining. Although the assigned dimensions in the parametric study show a negligible effect of OSH and OSA, the high OSH experience low subsidence in comparison with low OSH. Overall, the results demonstrate that the slope walls on the hanging wall side are mostly affected by the underground mining and high-stress concentration prevails near slope toes and pit bottom. Additionally, slope deformation decrease from pit bottom towards the slope crest and surface. The results of this study add knowledge to open pit and underground mining interaction.
文摘Effects of two important factors on earthquake response of high arch dams are considered and combined into one program.These tactors are:effects of radiation damping of the infinite canyon and local non-linearity of the contraction joint opening between the dam monoliths.For modeling of rock canyon,the discrete parameters are obtained based on a curve fitting, thus allowing the nonlinear dam system to be solved in the time domain.The earthquake uniform tree-field input at the dam-canyon interface is used.An engineering example is given to demonstrate the significant effects of the radiation damping on the structure response.
文摘This research describes a quantitative,rapid,and low-cost methodology for debris flow susceptibility evaluation at the basin scale using open-access data and geodatabases.The proposed approach can aid decision makers in land management and territorial planning,by first screening for areas with a higher debris flow susceptibility.Five environmental predisposing factors,namely,bedrock lithology,fracture network,quaternary deposits,slope inclination,and hydrographic network,were selected as independent parameters and their mutual interactions were described and quantified using the Rock Engineering System(RES)methodology.For each parameter,specific indexes were proposed,aiming to provide a final synthetic and representative index of debris flow susceptibility at the basin scale.The methodology was tested in four basins located in the Upper Susa Valley(NW Italian Alps)where debris flow events are the predominant natural hazard.The proposed matrix can represent a useful standardized tool,universally applicable,since it is independent of type and characteristic of the basin.
