In the past decades,physical modeling has been widely used in hydrogeology for teaching,studying and exhibition purposes.Most of these models are used to illustrate hydrogeological profiles,but few can depict three-di...In the past decades,physical modeling has been widely used in hydrogeology for teaching,studying and exhibition purposes.Most of these models are used to illustrate hydrogeological profiles,but few can depict three-dimensional groundwater flows,making it impossible to validate groundwater flows simulated by numerical methods with physical modeling.展开更多
This paper describes the function,structure and working status of the data buffer unitDBU,one of the most important functional units on ITM-1.It also discusses DBU’s supportto the multiprocessor system and Prolog lan...This paper describes the function,structure and working status of the data buffer unitDBU,one of the most important functional units on ITM-1.It also discusses DBU’s supportto the multiprocessor system and Prolog language.展开更多
Approaches to efficiency in manufacturing and assem bl y over the past 100 years have concentrated frequently on the twin themes of div iding jobs done by people into defined segments and to automating as many of tho ...Approaches to efficiency in manufacturing and assem bl y over the past 100 years have concentrated frequently on the twin themes of div iding jobs done by people into defined segments and to automating as many of tho se segments as possible. This approach to manufacturing engineering may be char acterised as one of deconstruction and replacement so far as the role of the hum an being is concerned. More recently design engineering has been approached in a similar light with research into ’intelligent’ methods involving, for example, expert systems or genetic algorithms to handle an increasing proportion of desi gn tasks. Expert systems are predicated on the idea that it is possible to capture and systemise significant amounts of professional knowledge: a task that has proved with experience to be much more difficult than when such systems wer e first proposed. Genetic algorithms, notwithstanding considerable research eff ort, have yet to make significant inroads into the practise of design and manufa cture. This paper will draw on new and previous experimental work carried out with supp ort from industry to propose an alternative approach that is enabled by the prod ucts of modern information technology. In this paradigm it is recognised that t he involvement of the human design expert is, for the time being at least, inevi table. Rather than seeking to reduce or even eliminate the " expert" with his or her tacit knowledge, the aim is to provide the expert with interactive to ols including immersive virtual reality so that implicit, human expertise can be applied effectively in the design cycle. The proposed approach is considered in the context of a particularly costly and difficult task, namely the design and planning for manufacture and assembly of c able harnesses for use in electro-mechanical artefacts. The efficient and reli able manufacture of cabling systems for many such products in the aerospace, aut omotive and IT sectors provides diverse challenges to designers, manufacturers a nd cable installers. Cable harness layouts are often so complex that design tend s to be carried out as an end activity, which may lead to higher costs, or even a product redesign. Current practice usually requires scaled or full-sized phys ical prototypes onto which the cable layout is constructed as the last productio n process. This is the case even when advanced CAD systems are used for this an d other parts of the design. Problems encountered at the cable harness design st age have a marked impact on the time needed for new product introductions. A prototype immersive system for cable harness design, developed by the research team has been used tested in experiments carried out in collaboration with indu stry. This work has shown that the task completion times obtained by the partici pants were between two and five times faster in than current CAD systems; even t hough the experiments were heavily biased towards CAD. The Virtual Reality inter face, with fewer mouse clicks and keyboard inputs, appears to have a significant impact on completion times. Cable harness design requires in-depth three-dimensional spatial reasoning whi ch CAD systems tend to lack due to their conventional flat screen display. Resul ts so far show evidence that the two or three degrees of freedom of movement on a flat screen provided by current CAD cable harness systems inhibits the user’s ability to route cable layouts especially in complex 3D assemblies. Immersive V R, on the other hand gives users the ability to change their viewpoint quickly a nd provides six degrees of freedom of movement thus showing great promise as a s uitable environment for routing cable. Initial results and feedback from the industrial partners are encouraging and su pport the theme of the research paradigm. Rather than seeking to reduce or even eliminate the ’expert’ with his or her tacit knowledge, the aim is to provide t he expert with interactive tools including immersive virtual reality so that implicit, human expertise can be applied most展开更多
As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas e...As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas es. A key component of an integrated environment is the use of computational eng ineering to assist and support solutions for complex design. Computer methods fo r structural, flow and thermal analysis are well developed and have been used in design for many years. Many software packages are now available which provi de an advanced capability. However, they are not designed for modelling of powde r forming processes. This paper describes the powder compaction software (PCS_SU T), which is designed for pre- and post-processing for computational simulatio n of the process compaction of powder. In the PCS_SUT software, the adaptive analysis of transient metal powder forming process is simulated by the finite element method based on deformation theories . The error estimates and adaptive remeshing schemes are applied for updated co -ordinate analysis. A generalized Newmark scheme is used for the time domain di scretization and the final nonlinear equations are solved by a Newton-Raphson p rocedure. An incremental elasto-plastic material model is used to simulate the compaction process. To describe the constitutive model of nonlinear behaviour of powder materials, a combination of Mohr-Coulomb and elliptical yield cap model is applied. This model reflects the yielding, frictional and densification char acteristics of powder along with strain and geometrical hardening which occurs d uring the compaction process. A hardening rule is used to define the dependence of the yield surface on the degree of plastic straining. A plasticity theory for friction is employed in the treatment of the powder-tooling interface. The inv olvement of two different materials, which have contact and relative movement in relation to each other, must be considered. A special formulation for friction modelling is coupled with a material formulation. The interface behaviour betwee n the die and the powder is modelled by using an interface element mesh. In the present paper, we have demonstrated pre- and post-processor finite elem ent software, written in Visual Basic, to generate the graphical model and visua lly display the computed results. The software consist of three main part: · Pre-processor: It is used to create the model, generate an app ropriate finite element grid, apply the appropriate boundary conditions, and vie w the total model. The geometric model can be used to associate the mesh with th e physical attributes such as element properties, material properties, or loads and boundary conditions. · Analysis: It can deal with two-dimensional and axi-symmetric applications for linear and non-linear behaviour of material in static and dyna mic analyses. Both triangular and quadrilateral elements are available in the e lement library, including 3-noded, 6-noded and 7-noded (T6B1) triangles and 4 -noded, 8-noded and 9-noded quadrilaterals. The direct implicit algorithm bas ed on the generalized Newmark scheme is used for the time integration and an aut omatic time step control facility is provided. For non-linear iteration, choice s among fully or modified Newton-Raphson method and quasi-Newton method, using the initial stiffness method, Davidon inverse method or BFGS inverse method, ar e possible. · Post-processor: It provides visualization of the computed resu lts, when the finite element model and analysis have been completed. Post-proce ssing is vital to allow the appropriate interpretation of the completed results of the finite element analysis. It provides the visual means to interpret the va st amounts of computed results generated. Finally, the powder behaviour during the compaction of a multi-level component is numerically simulated by the PCS_SUT software, as shown in Fig.1. The predict ive compaction forces at different displacements are computed and compared with the available experimental展开更多
The tokamak HT-7U project has been funded as a Chinese national project since 1998. The main object of the project is to build a nuclear fusion experimental device with divertor configuration, which is designed by the...The tokamak HT-7U project has been funded as a Chinese national project since 1998. The main object of the project is to build a nuclear fusion experimental device with divertor configuration, which is designed by the Institute of Plasma Physics, the Chinese Academy of Sciences (ASIPP). It is a full superconducting device, consisting of superconducting toroidal field (TF) coils and superconducting poloidal field (PF) coil. During the operation of the device, the operational parameter of device should be checked by technical diagnosis. This paper describes the design of circuit for checldng short between every two parts of the HT7U device. The main contents of design include circuit of data acquisition and data processing of computer.展开更多
The authors applied the first total ankle with partial tibial replacement forthe tumor of the tibia and fibula in 1987. We have followed this case for 10 years.Up to now, the outcome of this operation is very good, wi...The authors applied the first total ankle with partial tibial replacement forthe tumor of the tibia and fibula in 1987. We have followed this case for 10 years.Up to now, the outcome of this operation is very good, with no tumor recurrenceand good function. According to the experiences, the authors raised the technicalindexes of design, the indications, incision, surgical procedures, and warnings.展开更多
This paper summarizes the design and implementation notes of the CodDdBase system,which is a corn binative distributed database management system family based on an integrated object model.CoDdBase is implemented in C...This paper summarizes the design and implementation notes of the CodDdBase system,which is a corn binative distributed database management system family based on an integrated object model.CoDdBase is implemented in CLUSTER 86,a general purposed object-oriented programming language designed by the authors.The CoDdBase environment is actually a part of the CLUSTER 86 programming environment,which offers various object-based models,supplies miscellaneous building blocks for constructing different distributed DBMS's,and provides integrated programming tools to develop new ways and new models in response to changing application needs.展开更多
Optical simulations of GaAs/AlGaAs thin-film waveguides were performed for investigating the dependence of the modal behavior on waveguide geometry and the resulting analytical sensitivity. Simulations were performed ...Optical simulations of GaAs/AlGaAs thin-film waveguides were performed for investigating the dependence of the modal behavior on waveguide geometry and the resulting analytical sensitivity. Simulations were performed for two distinct mid-infrared wavelengths, thereby demonstrating the necessity of individually designed waveguide structures for each spectral regime of interest. Hence, the modal behavior, sensitivity, and intensity of the evanescent field were investigated via modeling studies at 1600 and 1000 cm^(-1), thereby confirming the utility of such simulations for designing mid-infrared sensors based on thin-film waveguide technology.展开更多
In July of 1987, the Sampling Survey of Children's Situation was conducted in 9 provincesautonomous regions of China. A stratified two--stage cluster sampling plan was designed for thesurvey. The paper presents th...In July of 1987, the Sampling Survey of Children's Situation was conducted in 9 provincesautonomous regions of China. A stratified two--stage cluster sampling plan was designed for thesurvey. The paper presents the methods of stratification, selecting n=2 PSU's (cities/counties) withunequal probabilities without replacement in each stratum and selecting residents/village committeein each sampled city/county. All formulae of estimating population characteristics (especiallypopulation totals and the ratios of two totals), and estimating variances of those estimators aregiven. Finally, we analyse the precision of the survey preliminarily from the result of dataprocessing.展开更多
A kind of new acoustic liner with adjustable impedance has been proposed. At the same time, a set of control system has been designed for this kind of liner. Many experimental results have been obtained based on this ...A kind of new acoustic liner with adjustable impedance has been proposed. At the same time, a set of control system has been designed for this kind of liner. Many experimental results have been obtained based on this control system. In fact, the present investigation shows the possibi1ity of active control of sound absorption coefficient or impedance of a liner according to external sound source condition by means of a standing wave tube. The experimental results show that the sound absorption coefficient of the liner can keep optimal under any sound source condition by controlling the cavity depth and the flow rate through the perforated plate of the liner. In addition, hoth the resistance and the reactance of the liner can also be controlled independently corresponding to any given condition. which is necessary to control unsteady How in turbomachinery.展开更多
The presented work will show the highest relevance of solving all the issues related to this problem and present the results of the analysis of the main expected potential problems,which may occur in the implementatio...The presented work will show the highest relevance of solving all the issues related to this problem and present the results of the analysis of the main expected potential problems,which may occur in the implementation of the INDUSTRY-4.0 reform.It is proved that the pace and level of development of this reform will be determined to a large extent by the effectiveness of the individual nodes used and the entire mechatronic system.It has also been established that as a result of systematic miniaturization of the nodes of radio-electronic equipment and microelectronic equipment and microelectronic technology,the main problem of these reforms and the implementation of complex technological processes is instrumental and technological support,especially with cutting micro-tools and equipment.Therefore,on the example of these investigations,methods for improving their performance are shown.展开更多
Because of its good condition with mechanics, logarithmic spiral double curve arch bam has been widely used in the practical engineering. The introduction of a new method in how to divide transverse joint in arch dam ...Because of its good condition with mechanics, logarithmic spiral double curve arch bam has been widely used in the practical engineering. The introduction of a new method in how to divide transverse joint in arch dam will be given and the further research of its calculation has been done. The C++ is used in electronic procedure and the 3D simulation has been finished with AutoCAD, which will provide the object model for computer simulation of the arch dam and the division of finite element mesh. Meanwhile, this method in dividing the transverse joint in arch dam also can be taken as the calculated basis for the design and calculation of arch dam, construction lofting and the calculation of the work amount.展开更多
基金supported by the State Key Program of National Natural Science of China(Grant No.41130637)
文摘In the past decades,physical modeling has been widely used in hydrogeology for teaching,studying and exhibition purposes.Most of these models are used to illustrate hydrogeological profiles,but few can depict three-dimensional groundwater flows,making it impossible to validate groundwater flows simulated by numerical methods with physical modeling.
基金the High Technology Research and Development Programme of china.
文摘This paper describes the function,structure and working status of the data buffer unitDBU,one of the most important functional units on ITM-1.It also discusses DBU’s supportto the multiprocessor system and Prolog language.
文摘Approaches to efficiency in manufacturing and assem bl y over the past 100 years have concentrated frequently on the twin themes of div iding jobs done by people into defined segments and to automating as many of tho se segments as possible. This approach to manufacturing engineering may be char acterised as one of deconstruction and replacement so far as the role of the hum an being is concerned. More recently design engineering has been approached in a similar light with research into ’intelligent’ methods involving, for example, expert systems or genetic algorithms to handle an increasing proportion of desi gn tasks. Expert systems are predicated on the idea that it is possible to capture and systemise significant amounts of professional knowledge: a task that has proved with experience to be much more difficult than when such systems wer e first proposed. Genetic algorithms, notwithstanding considerable research eff ort, have yet to make significant inroads into the practise of design and manufa cture. This paper will draw on new and previous experimental work carried out with supp ort from industry to propose an alternative approach that is enabled by the prod ucts of modern information technology. In this paradigm it is recognised that t he involvement of the human design expert is, for the time being at least, inevi table. Rather than seeking to reduce or even eliminate the " expert" with his or her tacit knowledge, the aim is to provide the expert with interactive to ols including immersive virtual reality so that implicit, human expertise can be applied effectively in the design cycle. The proposed approach is considered in the context of a particularly costly and difficult task, namely the design and planning for manufacture and assembly of c able harnesses for use in electro-mechanical artefacts. The efficient and reli able manufacture of cabling systems for many such products in the aerospace, aut omotive and IT sectors provides diverse challenges to designers, manufacturers a nd cable installers. Cable harness layouts are often so complex that design tend s to be carried out as an end activity, which may lead to higher costs, or even a product redesign. Current practice usually requires scaled or full-sized phys ical prototypes onto which the cable layout is constructed as the last productio n process. This is the case even when advanced CAD systems are used for this an d other parts of the design. Problems encountered at the cable harness design st age have a marked impact on the time needed for new product introductions. A prototype immersive system for cable harness design, developed by the research team has been used tested in experiments carried out in collaboration with indu stry. This work has shown that the task completion times obtained by the partici pants were between two and five times faster in than current CAD systems; even t hough the experiments were heavily biased towards CAD. The Virtual Reality inter face, with fewer mouse clicks and keyboard inputs, appears to have a significant impact on completion times. Cable harness design requires in-depth three-dimensional spatial reasoning whi ch CAD systems tend to lack due to their conventional flat screen display. Resul ts so far show evidence that the two or three degrees of freedom of movement on a flat screen provided by current CAD cable harness systems inhibits the user’s ability to route cable layouts especially in complex 3D assemblies. Immersive V R, on the other hand gives users the ability to change their viewpoint quickly a nd provides six degrees of freedom of movement thus showing great promise as a s uitable environment for routing cable. Initial results and feedback from the industrial partners are encouraging and su pport the theme of the research paradigm. Rather than seeking to reduce or even eliminate the ’expert’ with his or her tacit knowledge, the aim is to provide t he expert with interactive tools including immersive virtual reality so that implicit, human expertise can be applied most
文摘As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas es. A key component of an integrated environment is the use of computational eng ineering to assist and support solutions for complex design. Computer methods fo r structural, flow and thermal analysis are well developed and have been used in design for many years. Many software packages are now available which provi de an advanced capability. However, they are not designed for modelling of powde r forming processes. This paper describes the powder compaction software (PCS_SU T), which is designed for pre- and post-processing for computational simulatio n of the process compaction of powder. In the PCS_SUT software, the adaptive analysis of transient metal powder forming process is simulated by the finite element method based on deformation theories . The error estimates and adaptive remeshing schemes are applied for updated co -ordinate analysis. A generalized Newmark scheme is used for the time domain di scretization and the final nonlinear equations are solved by a Newton-Raphson p rocedure. An incremental elasto-plastic material model is used to simulate the compaction process. To describe the constitutive model of nonlinear behaviour of powder materials, a combination of Mohr-Coulomb and elliptical yield cap model is applied. This model reflects the yielding, frictional and densification char acteristics of powder along with strain and geometrical hardening which occurs d uring the compaction process. A hardening rule is used to define the dependence of the yield surface on the degree of plastic straining. A plasticity theory for friction is employed in the treatment of the powder-tooling interface. The inv olvement of two different materials, which have contact and relative movement in relation to each other, must be considered. A special formulation for friction modelling is coupled with a material formulation. The interface behaviour betwee n the die and the powder is modelled by using an interface element mesh. In the present paper, we have demonstrated pre- and post-processor finite elem ent software, written in Visual Basic, to generate the graphical model and visua lly display the computed results. The software consist of three main part: · Pre-processor: It is used to create the model, generate an app ropriate finite element grid, apply the appropriate boundary conditions, and vie w the total model. The geometric model can be used to associate the mesh with th e physical attributes such as element properties, material properties, or loads and boundary conditions. · Analysis: It can deal with two-dimensional and axi-symmetric applications for linear and non-linear behaviour of material in static and dyna mic analyses. Both triangular and quadrilateral elements are available in the e lement library, including 3-noded, 6-noded and 7-noded (T6B1) triangles and 4 -noded, 8-noded and 9-noded quadrilaterals. The direct implicit algorithm bas ed on the generalized Newmark scheme is used for the time integration and an aut omatic time step control facility is provided. For non-linear iteration, choice s among fully or modified Newton-Raphson method and quasi-Newton method, using the initial stiffness method, Davidon inverse method or BFGS inverse method, ar e possible. · Post-processor: It provides visualization of the computed resu lts, when the finite element model and analysis have been completed. Post-proce ssing is vital to allow the appropriate interpretation of the completed results of the finite element analysis. It provides the visual means to interpret the va st amounts of computed results generated. Finally, the powder behaviour during the compaction of a multi-level component is numerically simulated by the PCS_SUT software, as shown in Fig.1. The predict ive compaction forces at different displacements are computed and compared with the available experimental
文摘The tokamak HT-7U project has been funded as a Chinese national project since 1998. The main object of the project is to build a nuclear fusion experimental device with divertor configuration, which is designed by the Institute of Plasma Physics, the Chinese Academy of Sciences (ASIPP). It is a full superconducting device, consisting of superconducting toroidal field (TF) coils and superconducting poloidal field (PF) coil. During the operation of the device, the operational parameter of device should be checked by technical diagnosis. This paper describes the design of circuit for checldng short between every two parts of the HT7U device. The main contents of design include circuit of data acquisition and data processing of computer.
文摘The authors applied the first total ankle with partial tibial replacement forthe tumor of the tibia and fibula in 1987. We have followed this case for 10 years.Up to now, the outcome of this operation is very good, with no tumor recurrenceand good function. According to the experiences, the authors raised the technicalindexes of design, the indications, incision, surgical procedures, and warnings.
文摘This paper summarizes the design and implementation notes of the CodDdBase system,which is a corn binative distributed database management system family based on an integrated object model.CoDdBase is implemented in CLUSTER 86,a general purposed object-oriented programming language designed by the authors.The CoDdBase environment is actually a part of the CLUSTER 86 programming environment,which offers various object-based models,supplies miscellaneous building blocks for constructing different distributed DBMS's,and provides integrated programming tools to develop new ways and new models in response to changing application needs.
基金funding from the European Union’s Seventh Framework Programme managed by REA Research Executive Agency http://ec.europa.eu/rea (FP7/2007-2013) under grant agreement no.314018 FP7-SME-2012-SMEsupport of this study by the Kompetenznetz Funktionelle Nanostrukturen Baden Wuerttemberg,Germany
文摘Optical simulations of GaAs/AlGaAs thin-film waveguides were performed for investigating the dependence of the modal behavior on waveguide geometry and the resulting analytical sensitivity. Simulations were performed for two distinct mid-infrared wavelengths, thereby demonstrating the necessity of individually designed waveguide structures for each spectral regime of interest. Hence, the modal behavior, sensitivity, and intensity of the evanescent field were investigated via modeling studies at 1600 and 1000 cm^(-1), thereby confirming the utility of such simulations for designing mid-infrared sensors based on thin-film waveguide technology.
基金Supported partially by the National Funds of Natural Sciences, 7860013
文摘In July of 1987, the Sampling Survey of Children's Situation was conducted in 9 provincesautonomous regions of China. A stratified two--stage cluster sampling plan was designed for thesurvey. The paper presents the methods of stratification, selecting n=2 PSU's (cities/counties) withunequal probabilities without replacement in each stratum and selecting residents/village committeein each sampled city/county. All formulae of estimating population characteristics (especiallypopulation totals and the ratios of two totals), and estimating variances of those estimators aregiven. Finally, we analyse the precision of the survey preliminarily from the result of dataprocessing.
文摘A kind of new acoustic liner with adjustable impedance has been proposed. At the same time, a set of control system has been designed for this kind of liner. Many experimental results have been obtained based on this control system. In fact, the present investigation shows the possibi1ity of active control of sound absorption coefficient or impedance of a liner according to external sound source condition by means of a standing wave tube. The experimental results show that the sound absorption coefficient of the liner can keep optimal under any sound source condition by controlling the cavity depth and the flow rate through the perforated plate of the liner. In addition, hoth the resistance and the reactance of the liner can also be controlled independently corresponding to any given condition. which is necessary to control unsteady How in turbomachinery.
基金This work was supported by Shota Rustaveli National Science Foundation(SRNSF)[PHDF-19-2224,Improving the efficiency of mechatronic systems in order to ensure the reform of“Industry-4.0”].
文摘The presented work will show the highest relevance of solving all the issues related to this problem and present the results of the analysis of the main expected potential problems,which may occur in the implementation of the INDUSTRY-4.0 reform.It is proved that the pace and level of development of this reform will be determined to a large extent by the effectiveness of the individual nodes used and the entire mechatronic system.It has also been established that as a result of systematic miniaturization of the nodes of radio-electronic equipment and microelectronic equipment and microelectronic technology,the main problem of these reforms and the implementation of complex technological processes is instrumental and technological support,especially with cutting micro-tools and equipment.Therefore,on the example of these investigations,methods for improving their performance are shown.
基金Supported by Postgraduate education innovation fund of Chongqing Jiaotong University 2010
文摘Because of its good condition with mechanics, logarithmic spiral double curve arch bam has been widely used in the practical engineering. The introduction of a new method in how to divide transverse joint in arch dam will be given and the further research of its calculation has been done. The C++ is used in electronic procedure and the 3D simulation has been finished with AutoCAD, which will provide the object model for computer simulation of the arch dam and the division of finite element mesh. Meanwhile, this method in dividing the transverse joint in arch dam also can be taken as the calculated basis for the design and calculation of arch dam, construction lofting and the calculation of the work amount.