Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in auto-matic cavity design bas...Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in auto-matic cavity design based on the my-testing model. A new ray-testing approach is presented to classify the part surfaces to core/cavity surfaces and undercut surfaces by automatic identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. The algorithm is robust and adapted to rather complicated geometry, so it is valuable in computer-aided mold design systems. To validate the efficiency of the approach, an experimental program is implemented. Case studies show that the approach is practical and valuable in automatic parting line and parting surface generation.展开更多
A midlatitude squall line passed over the array of the Cooperative Convective Precipitation Experiment (CCOPE) on 1 August 1981. The structure and evolution of the squall line, and the correlations of the storm with s...A midlatitude squall line passed over the array of the Cooperative Convective Precipitation Experiment (CCOPE) on 1 August 1981. The structure and evolution of the squall line, and the correlations of the storm with surface thermodynamics and kinematic fields are investigated, mainly by using radar and surface mesonet data in CCOPE. The storm-wide precipitation efficiency is also estimated.The squall line was of an obvious process of metabolism. Thirty-four cells formed successively in front of the primary storm and eventually merged into it during the period 1700-2010 MDT. The newest cells formed near surface equivalent potential temperature maxima, and near surface moisture flux convergence zones or / and the 'temperature break lines'. The thunderstorm rainfall, with the precipitation efficiency of 54%, lags 25-30 min behind the moisture flux convergence on the average.展开更多
A new concept of design and manufacturing of ruled surface based on line geometry is proposed. Some practical algorithm for CAD system is derived. Some problems in design and manufacturing of ruled surface can be solv...A new concept of design and manufacturing of ruled surface based on line geometry is proposed. Some practical algorithm for CAD system is derived. Some problems in design and manufacturing of ruled surface can be solved by using the algorithm.展开更多
This is an expand of the complex function method in solving the problem of interaction of plane.SH-waves and non-circular cavity surfaced with linig in anisotropic media.the use the method similar to that incorporated...This is an expand of the complex function method in solving the problem of interaction of plane.SH-waves and non-circular cavity surfaced with linig in anisotropic media.the use the method similar to that incorporated in [2] added with Savin's method for solving stress concentration of non-circular cavity surfaced with lining in elasticity.Anisotropic media can be used ic simulate the conditions of thegeology.The solving proceeding for this problem can be processed conveniently in the manner similar to that introduced in [2].In this paper.as illustrated in example numerical studies have been done for a square cavity surfaced with lining in anisotropic media.展开更多
The transmission upper limit of a double-layer frequency selective surface （FSS） with two infinitely thin metal arrays is pre- sented based on the study of the general equivalent transmission line model of a double-...The transmission upper limit of a double-layer frequency selective surface （FSS） with two infinitely thin metal arrays is pre- sented based on the study of the general equivalent transmission line model of a double-layer FSS. Results of theoretical analyses, numerical simulations and experiments show that this transmis- sion upper limit is independent of the array and the element, which indicates that it is impossible to achieve a transmission upper limit higher than this one under a given incident and dielectric- supporting condition by the design of the periodic array. Both the applicable condition and the possible application of the transmis- sion upper limit are discussed. The results show that the transmis- sion upper limit not only has a good reachability, but also provides a key to effectively improve the transmission performance of a double-layer FSS or more complex frequency selective structures.展开更多
based on optimal design on the core element of the sensor,a wireless and passive surface acoustic wave（SAW）temperature sensor integrated with ID Tag was presented.A reflective delay line,which consists of a transduc...based on optimal design on the core element of the sensor,a wireless and passive surface acoustic wave（SAW）temperature sensor integrated with ID Tag was presented.A reflective delay line,which consists of a transducer and eight reflectors on YZ LiNbO3 substrate.Was fabricated as the sensor element,in which,three reflectors were used for temperature sensing,and the other five were for the ID Tag using phase encoding.Single phase unidirectional transducers（SPUDTs）and shorted grating were used to structure the sAW device,leading to excellent signal to noise ratio（SNR）.The performance of the SAW device was simulated by the coupling of modes（COM）prior to fabrication.Using the network analyzer,the response in time domain of the fabricated 434 MHz SAW sensor was characterized,the measured S11 agrees well with the simulated one,sharp reflection peaks,high signal/noise,and low spurious noise between the reflection peaks were observed.Using the radar system based on FSCW as the reader unit.the developed SAW temperature sensors were evaluated wirelessly.Excellent1 inearity and good resolution of士1℃ were observed.展开更多
文摘Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in auto-matic cavity design based on the my-testing model. A new ray-testing approach is presented to classify the part surfaces to core/cavity surfaces and undercut surfaces by automatic identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. The algorithm is robust and adapted to rather complicated geometry, so it is valuable in computer-aided mold design systems. To validate the efficiency of the approach, an experimental program is implemented. Case studies show that the approach is practical and valuable in automatic parting line and parting surface generation.
文摘A midlatitude squall line passed over the array of the Cooperative Convective Precipitation Experiment (CCOPE) on 1 August 1981. The structure and evolution of the squall line, and the correlations of the storm with surface thermodynamics and kinematic fields are investigated, mainly by using radar and surface mesonet data in CCOPE. The storm-wide precipitation efficiency is also estimated.The squall line was of an obvious process of metabolism. Thirty-four cells formed successively in front of the primary storm and eventually merged into it during the period 1700-2010 MDT. The newest cells formed near surface equivalent potential temperature maxima, and near surface moisture flux convergence zones or / and the 'temperature break lines'. The thunderstorm rainfall, with the precipitation efficiency of 54%, lags 25-30 min behind the moisture flux convergence on the average.
文摘A new concept of design and manufacturing of ruled surface based on line geometry is proposed. Some practical algorithm for CAD system is derived. Some problems in design and manufacturing of ruled surface can be solved by using the algorithm.
文摘This is an expand of the complex function method in solving the problem of interaction of plane.SH-waves and non-circular cavity surfaced with linig in anisotropic media.the use the method similar to that incorporated in [2] added with Savin's method for solving stress concentration of non-circular cavity surfaced with lining in elasticity.Anisotropic media can be used ic simulate the conditions of thegeology.The solving proceeding for this problem can be processed conveniently in the manner similar to that introduced in [2].In this paper.as illustrated in example numerical studies have been done for a square cavity surfaced with lining in anisotropic media.
文摘The transmission upper limit of a double-layer frequency selective surface （FSS） with two infinitely thin metal arrays is pre- sented based on the study of the general equivalent transmission line model of a double-layer FSS. Results of theoretical analyses, numerical simulations and experiments show that this transmis- sion upper limit is independent of the array and the element, which indicates that it is impossible to achieve a transmission upper limit higher than this one under a given incident and dielectric- supporting condition by the design of the periodic array. Both the applicable condition and the possible application of the transmis- sion upper limit are discussed. The results show that the transmis- sion upper limit not only has a good reachability, but also provides a key to effectively improve the transmission performance of a double-layer FSS or more complex frequency selective structures.
基金supported by the National Nature Science Foundation of China(11074268,10834010)
文摘based on optimal design on the core element of the sensor,a wireless and passive surface acoustic wave（SAW）temperature sensor integrated with ID Tag was presented.A reflective delay line,which consists of a transducer and eight reflectors on YZ LiNbO3 substrate.Was fabricated as the sensor element,in which,three reflectors were used for temperature sensing,and the other five were for the ID Tag using phase encoding.Single phase unidirectional transducers（SPUDTs）and shorted grating were used to structure the sAW device,leading to excellent signal to noise ratio（SNR）.The performance of the SAW device was simulated by the coupling of modes（COM）prior to fabrication.Using the network analyzer,the response in time domain of the fabricated 434 MHz SAW sensor was characterized,the measured S11 agrees well with the simulated one,sharp reflection peaks,high signal/noise,and low spurious noise between the reflection peaks were observed.Using the radar system based on FSCW as the reader unit.the developed SAW temperature sensors were evaluated wirelessly.Excellent1 inearity and good resolution of士1℃ were observed.
