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6.5 kV n-Channel 4H-SiC IGBT with Low Switching Loss Achieved by Extremely Thin Drift Layer
(Switzerland: Trans Tech Publications, 2016), 9 page(s)
Thin drift layers were used to realize n-channel 4H-SiC IGBTs with an extremely low switching loss. The thickness of a drift layer was 60 µm, which was designed for a blocking voltage of 6.5 kV. An on-voltage of 5.4 V was obtained at a collector current of 100 A/cm2 and the specific differential on-resistance at...
Sample
(Switzerland: Trans Tech Publications, 2016), 9 page(s)
Description
Thin drift layers were used to realize n-channel 4H-SiC IGBTs with an extremely low switching loss. The thickness of a drift layer was 60 µm, which was designed for a blocking voltage of 6.5 kV. An on-voltage of 5.4 V was obtained at a collector current of 100 A/cm2 and the specific differential on-resistance at 100 A/cm2 was 20 mOcm2 at room temperature, indicating proper bipolar operation. A switching evaluation of the SiC IGBTs was performed...
Thin drift layers were used to realize n-channel 4H-SiC IGBTs with an extremely low switching loss. The thickness of a drift layer was 60 µm, which was designed for a blocking voltage of 6.5 kV. An on-voltage of 5.4 V was obtained at a collector current of 100 A/cm2 and the specific differential on-resistance at 100 A/cm2 was 20 mOcm2 at room temperature, indicating proper bipolar operation. A switching evaluation of the SiC IGBTs was performed with a bus voltage of 3.6 kV and a load current of 10 A, and a turn-off loss of 1.2 mJ was obtained. This turn-off loss is very small compared to the values in the current literatures, and was estimated to be an over 80% reduction. The series operation of thin-drift-layer 6.5 kV SiC IGBTs can ensure a lower switching loss than the single operation of higher blocking voltage devices in power conversion systems.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2016-05, 2016
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2016 Trans Tech Publications Ltd.
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2D Barcode Identification Technology Application in Tool Management System for Workshop
(Switzerland: Trans Tech Publications, 2016), 9 page(s)
With the development of advanced automation degree industries, the requirements of network management for workshop tool become more and more urgent. A very important part in network management system is identification technology of the tool. In this paper, 2D (two-dimensional) barcode identification technology is...
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(Switzerland: Trans Tech Publications, 2016), 9 page(s)
Description
With the development of advanced automation degree industries, the requirements of network management for workshop tool become more and more urgent. A very important part in network management system is identification technology of the tool. In this paper, 2D (two-dimensional) barcode identification technology is applied in the tool information in real-time query to realize network management. The 2D barcode reading device, which is combined with...
With the development of advanced automation degree industries, the requirements of network management for workshop tool become more and more urgent. A very important part in network management system is identification technology of the tool. In this paper, 2D (two-dimensional) barcode identification technology is applied in the tool information in real-time query to realize network management. The 2D barcode reading device, which is combined with the local computer decoding software, could achieve communication between production line and the server. By using 2D barcode identification technology, it could achieve network management for workshop tool, improve production efficiency and reduce the artificial error.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2016-01, 2016
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2016 Trans Tech Publications Ltd.
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3D Numerical Model of the Subsoil-Structure Interaction and Comparison of the Results with Experimentally Measured Values
(Switzerland: Trans Tech Publications, 2017), 13 page(s)
The influence of the physically-nonlinear behaviour of the structure and interaction between the upper structure and foundation are the aspects which influence the results of the subsoil-structure interaction analysis. The experimental measurement of stress and strain and monitoring of stress-strain relations by i...
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(Switzerland: Trans Tech Publications, 2017), 13 page(s)
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The influence of the physically-nonlinear behaviour of the structure and interaction between the upper structure and foundation are the aspects which influence the results of the subsoil-structure interaction analysis. The experimental measurement of stress and strain and monitoring of stress-strain relations by interaction of foundation structures with subsoil are also performed at the Faculty of Civil Engineering, VS?B-TU Ostrava. Numerical ana...
The influence of the physically-nonlinear behaviour of the structure and interaction between the upper structure and foundation are the aspects which influence the results of the subsoil-structure interaction analysis. The experimental measurement of stress and strain and monitoring of stress-strain relations by interaction of foundation structures with subsoil are also performed at the Faculty of Civil Engineering, VS?B-TU Ostrava. Numerical analyses of contact task was made with FEM. The test sample for the task was a steel-fibre reinforced concrete foundation slab model loaded during experimental loading test. The calculated values of the subsidence do not correspond to the measured values of foundation subsidence of existing buildings, or values measured during the experiments. Results of the solutions are also different and depend on the choice of the model of the subsoil. Using several FEM software tools were made numerical analyses. Results of FEM analyses were also confronted with the values measured during the experiment.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2017-06, 2017
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2017 Trans Tech Publications Ltd.
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3D Topography Analysis of Ball-End Milled H-13 Die Steel Surfaces Using Wavelet Decomposition Method
(Switzerland: Trans Tech Publications, 2016), 10 page(s)
Optical profiler is employed to measure the surface topography of H-13 die steel machined by ball end cutter. By using 2D discret wavelet decomposition, the topographies of different frequency bands are obtained and the influence of cutter posture on varying frequncy bands topography is studied. The results show t...
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3D Topography Analysis of Ball-End Milled H-13 Die Steel Surfaces Using Wavelet Decomposition Method
(Switzerland: Trans Tech Publications, 2016), 10 page(s)
Description
Optical profiler is employed to measure the surface topography of H-13 die steel machined by ball end cutter. By using 2D discret wavelet decomposition, the topographies of different frequency bands are obtained and the influence of cutter posture on varying frequncy bands topography is studied. The results show that cutter posture has a great influence on the whole frequency band roughness. The changing trend of roughness is roughly the same und...
Optical profiler is employed to measure the surface topography of H-13 die steel machined by ball end cutter. By using 2D discret wavelet decomposition, the topographies of different frequency bands are obtained and the influence of cutter posture on varying frequncy bands topography is studied. The results show that cutter posture has a great influence on the whole frequency band roughness. The changing trend of roughness is roughly the same under different cutter postures which increase firstly then decrease with the decrease in frequency. A surface with a small high frequency roughness may have a large median frequency roughness.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2016-05, 2016
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2016 Trans Tech Publications Ltd.
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Accuracy and Material Properties in Incremental Forming for a Multi-Step Expanding Approach
(Switzerland: Trans Tech Publications, 2015), 10 page(s)
In incremental sheet forming the material properties change dependent on the wall angle. In addition to sheet thinning, material hardening can be observed and for stainless steel the formation of strain induced martensite has been reported. These process characteristics have been extensively examined for the formi...
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(Switzerland: Trans Tech Publications, 2015), 10 page(s)
Description
In incremental sheet forming the material properties change dependent on the wall angle. In addition to sheet thinning, material hardening can be observed and for stainless steel the formation of strain induced martensite has been reported. These process characteristics have been extensively examined for the forming of parts in one step. In this study, a first investigation is made to control the material properties independent on the wall angle...
In incremental sheet forming the material properties change dependent on the wall angle. In addition to sheet thinning, material hardening can be observed and for stainless steel the formation of strain induced martensite has been reported. These process characteristics have been extensively examined for the forming of parts in one step. In this study, a first investigation is made to control the material properties independent on the wall angle by a multi-step expanding approach. For this, in the first step a steep wall angle is formed and in the following steps this region is transformed to a shallow wall angle, keeping the material properties. To demonstrate and verify this new approach a small cone frustum with a wall angle of 60° was formed as a preform. This cone frustum was repeatedly expanded in steps of 2° to get finally a cone frustum with 30° wall angle. The stepwise expanding causes a considerably growing of the shape in depth direction, especially at the preformed area. By a heuristic approach the geometric accuracy of the final cone was optimized. The microhardness measurement of the formed cones shows that the final cone frustum has a region, where the material properties are similar to the first formed 60° wall angle. By this new approach the possibility to influence the material properties of the final part purely by tool path is demonstrated. In particular it is possible to form regions with shallow wall angles that have the material properties of regions with steep wall angles.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2015-03, 2015
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2015 Trans Tech Publications Ltd.
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Accurate and Traceable Calibration of the Stiffness of Various AFM Cantilevers
(Switzerland: Trans Tech Publications, 2015), 10 page(s)
Atomic force microscope (AFM) is widely used to measure nanoforce in the analysis of nanomechanical and biomechanical properties. As the critical factor in the nanoforce measurement, the stiffness of the AFM cantilever must be determined properly. In this paper, an accurate and SI-traceable calibration method is p...
Sample
(Switzerland: Trans Tech Publications, 2015), 10 page(s)
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Atomic force microscope (AFM) is widely used to measure nanoforce in the analysis of nanomechanical and biomechanical properties. As the critical factor in the nanoforce measurement, the stiffness of the AFM cantilever must be determined properly. In this paper, an accurate and SI-traceable calibration method is presented to obtain the stiffness of the AFM cantilever in the normal direction. The calibration system consists of a homemade AFM head...
Atomic force microscope (AFM) is widely used to measure nanoforce in the analysis of nanomechanical and biomechanical properties. As the critical factor in the nanoforce measurement, the stiffness of the AFM cantilever must be determined properly. In this paper, an accurate and SI-traceable calibration method is presented to obtain the stiffness of the AFM cantilever in the normal direction. The calibration system consists of a homemade AFM head and an ultra-precision electromagnetic balance. The calibration is based on the Hooke's law i.e. the stiffness is equal to the force divided by the deflection of the cantilever. With this system, three kinds of cantilevers were calibrated. The relative standard deviation is better than 1%. The results of these experiments showed good accuracy and repeatability.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2015-05, 2015
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2015 Trans Tech Publications Ltd.
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Achieving Concrete Durability in Chloride Exposures
(Switzerland: Trans Tech Publications, 2016), 9 page(s)
Obtaining durability in concrete structures over a long service life in chloride exposures requires knowledge of the concrete properties, relevant transport processes, depths of cover as well as minimization of cracking and construction defects. For example, imperfect curing can result in depth-dependent effects o...
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(Switzerland: Trans Tech Publications, 2016), 9 page(s)
Description
Obtaining durability in concrete structures over a long service life in chloride exposures requires knowledge of the concrete properties, relevant transport processes, depths of cover as well as minimization of cracking and construction defects. For example, imperfect curing can result in depth-dependent effects of the concrete cover's resistance to chloride ingress. Several service life models with various levels of sophistication exist for pred...
Obtaining durability in concrete structures over a long service life in chloride exposures requires knowledge of the concrete properties, relevant transport processes, depths of cover as well as minimization of cracking and construction defects. For example, imperfect curing can result in depth-dependent effects of the concrete cover's resistance to chloride ingress. Several service life models with various levels of sophistication exist for prediction of time-to-corrosion of concrete structures exposed to chlorides. The model inputs have uncertainty associated with them such as boundary conditions (level of saturation and temperature), cover depths, diffusion coefficients, time-dependent changes, and rates of buildup of chlorides at the surface. The performance test methods used to obtain predictive model inputs as well as how models handle these properties have a dramatic impact on predicted service lives. Very few models deal with the influence of cracks or the fact that concrete in the cover zone will almost certainly have a higher diffusion coefficient than the bulk concrete as the result of imperfect curing or compaction. While many models account for variability in input properties, they will never be able to account for extremes in construction defects. Therefore, to ensure the reliability of service life predictions and to attain a concrete structure that achieves its predicted potential, designers, contractors and suppliers need to work together, using proper inspection, to ensure proper detailing, minimize defects, and adopt adequate, yet achievable, curing procedures. As well, concrete structures are often exposed to other destructive elements in addition to chlorides (eg. freezing or ASR) and this adds another level of complexity since regardless of cause, cracks will accelerate the ingress of chlorides. These issues are discussed along with the need to use performance-based specifications together with predictive models.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2016-09, 2016
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2016 Trans Tech Publications Ltd.
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Action on Crane Runway Caused by Horizontal Forces due to Crane Skewing
(Switzerland: Trans Tech Publications, 2015), 11 page(s)
Determination of the (residual) lifetime of steel structures of construction, mining and maintenance machines has recently received increased attention, particularly for safety, environmental and economic reasons. One of the problems that are addressed in this context is crane skewing, a phenomenon that directly a...
Sample
(Switzerland: Trans Tech Publications, 2015), 11 page(s)
Description
Determination of the (residual) lifetime of steel structures of construction, mining and maintenance machines has recently received increased attention, particularly for safety, environmental and economic reasons. One of the problems that are addressed in this context is crane skewing, a phenomenon that directly affects, through friction and wear, the life of the crane guiding structure, and indirectly affects the secondary life of the crane supp...
Determination of the (residual) lifetime of steel structures of construction, mining and maintenance machines has recently received increased attention, particularly for safety, environmental and economic reasons. One of the problems that are addressed in this context is crane skewing, a phenomenon that directly affects, through friction and wear, the life of the crane guiding structure, and indirectly affects the secondary life of the crane supporting structure.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2015-10, 2015
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2015 Trans Tech Publications Ltd.
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Activity and Deactivation of ZSM-5 Catalysts in the Dimethyl Ether Synthesis from CO and H2 and Methanol Dehydration
(Switzerland: Trans Tech Publications, 2016), 11 page(s)
The increasing demand for producing dimethyl ether from synthesis gas explains the renewed interest in studying the activity and stability of catalysts. In the present work, resource catalytic testing of ZSM-5 zeolites was carried out in the one-step synthesis of dimethyl ether from synthesis gas for 120 hours. Fo...
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(Switzerland: Trans Tech Publications, 2016), 11 page(s)
Description
The increasing demand for producing dimethyl ether from synthesis gas explains the renewed interest in studying the activity and stability of catalysts. In the present work, resource catalytic testing of ZSM-5 zeolites was carried out in the one-step synthesis of dimethyl ether from synthesis gas for 120 hours. Formation of condensation products was observed on zeolite surface after catalytic tests which leads to lower catalytic activity of sampl...
The increasing demand for producing dimethyl ether from synthesis gas explains the renewed interest in studying the activity and stability of catalysts. In the present work, resource catalytic testing of ZSM-5 zeolites was carried out in the one-step synthesis of dimethyl ether from synthesis gas for 120 hours. Formation of condensation products was observed on zeolite surface after catalytic tests which leads to lower catalytic activity of samples. Condensation products were investigated by thermal analysis in an oxidizing atmosphere. Textural characteristics of zeolites before and after reaction were investigated. It was shown that methanol significantly contribute to formation of condensation products on the catalyst surface in the process of dimethyl ether production.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2016-02, 2016
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2016 Trans Tech Publications Ltd.
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Actuator from a Material with the High-Temperature Shape Memory Effect and Examples of its Application in Engineering
(Switzerland: Trans Tech Publications, 2016), 9 page(s)
The report provides designs of actuators from the shape memory material-nitinol. It is proposed to use rods, wire, sheets and tape as working elements of the actuators. Special attention is paid to the designs of composite multil-element actuators, working elements of which are connected in parallel or in series....
Sample
(Switzerland: Trans Tech Publications, 2016), 9 page(s)
Description
The report provides designs of actuators from the shape memory material-nitinol. It is proposed to use rods, wire, sheets and tape as working elements of the actuators. Special attention is paid to the designs of composite multil-element actuators, working elements of which are connected in parallel or in series. The experimental technique and results of experiments on evaluation of stresses developed by such actuators are given. It is shown that...
The report provides designs of actuators from the shape memory material-nitinol. It is proposed to use rods, wire, sheets and tape as working elements of the actuators. Special attention is paid to the designs of composite multil-element actuators, working elements of which are connected in parallel or in series. The experimental technique and results of experiments on evaluation of stresses developed by such actuators are given. It is shown that using the composite actuators from thin working elements facilitates control over their heating and cooling.
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Field of Study
Global Issues
Content Type
Periodical article
Date Published / Released
2016-02, 2016
Publisher
Trans Tech Publications
Topic / Theme
Engineering
Copyright Message
Copyright © 2016 Trans Tech Publications Ltd.
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