Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains,involving static aerodynamic forces and vortex-induced vibrations(VIVs).Static and dynamic sectiona...Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains,involving static aerodynamic forces and vortex-induced vibrations(VIVs).Static and dynamic sectional models of the girder and trains were employed for aerodynamic force measurement and VIV test,respectively.Results indicate that the aerodynamic interference effect on static aerodynamic forces of both the girder and trains is remarkable.When a single train exists,the horizontal position of the train has a small effect on aerodynamic coefficients of the girder.When two trains meet on the girder,the drag coefficient of the girder is significantly reduced compared with that of without train or with a single train;besides,during the whole meeting process,aerodynamic forces of the leeward train first drop and then increase suddenly.The fluctuation of aerodynamic force could cause redundant vibration of the train,which is unfavorable for safety and comfort.A train on the girder could worsen the girder VIV performance:a new vertical VIV appears in the triple-box girder when a train is on the girder,and the torsional VIV amplitude increases significantly when the train is on the windward side.展开更多
The article design the hardware system scheme using STM32F407 as the control core circuit, and designed the software structure of the system and application layer multi task and priority based on transplanted μ C/OS ...The article design the hardware system scheme using STM32F407 as the control core circuit, and designed the software structure of the system and application layer multi task and priority based on transplanted μ C/OS operating system. Aimed at that the traditional drunk driving detection system has low sensitivity and unable to distinguish diffuse alcohol sigmal interference. For accurate identification of pilot and crew alcohol concentration, the paper puts forward a driving intelligent identification wine system based on embedded μC/OS- II. The experimental results show that the detection sensitivity of the system has high accuracy rate, effectively prevent the purpose for the prevention of drunk driving, drunk driving has very good practical value.展开更多
The aim of the publication is to present the results of the research with the documents research method, involving studies of literature, legislation, and source acts on development of the system supporting the psycho...The aim of the publication is to present the results of the research with the documents research method, involving studies of literature, legislation, and source acts on development of the system supporting the psychological tests （psychological tests battery） of the police drivers, including the privileged drivers of the police. The system, in its assumptions, should inter alia allow to make assessment of intellectual and psychomotor skills as well as personality （in accordance with the detailed guidelines of annex 6 to Regulation of the Minister of Health of 8 ]uly 2014 on the psychological tests of the vehicles drivers using the tools of proven accuracy, reliability above .7, objective, standardised, and normalised within a group of police drivers）. The described research is conducted based on the grant for realisation of the development project： ＂Development of Psychological Tests Supporting System of the Drivers for the Police＂, no. DOB-BIO7/20/01/2015. The method for the research of the documents in the form of indirect observation allowed to analyse the legal acts, both national and international, and the laws in force in the European Union.展开更多
In the history of human space exploration, many failures of launch vehicles and spacecraft tare caused by vibration. At first, the periods in which the space products are in a vibration environment are discussed and t...In the history of human space exploration, many failures of launch vehicles and spacecraft tare caused by vibration. At first, the periods in which the space products are in a vibration environment are discussed and the need for vibration testing is then introduced. As the main content of this paper, the current situation of shaker systems is elaborated in detail. In this part, electrodynamic shakers, as the most widely used vibration generators, are illustrated in detail including structures, principles and performances. Special inventions worldwide in the development of electrodynamic shakers such as induction ring shakers, high force shakers, multi-axial vibration testing systems and combined environmental testing systems are presented. At last, the recent progress and outlook of shaker systems are summarized.展开更多
To investigate the aerodynamic effect of wind barriers on a high-speed train-bridge system,a sectional model test was conducted in a closed-circuit-type wind tunnel.Several different cases,including with and without b...To investigate the aerodynamic effect of wind barriers on a high-speed train-bridge system,a sectional model test was conducted in a closed-circuit-type wind tunnel.Several different cases,including with and without barriers,with different barrier heights and porosity rates,and with different train arrangements on the bridge were taken into consideration;in addition,the aerodynamic coefficients of the train-bridge system were measured.It is found that the side force and rolling moment coefficients of the vehicle are efficiently reduced by a single-side wind barrier,but for the bridge deck these values are increased.The height and porosity rate of the barrier are two important factors that influence the windbreak effect.Train arrangement on the bridge will considerably influence the aerodynamic properties of the train-bridge system.The side force and rolling moment coefficients of the vehicle at the windward side are larger than at the leeward side.展开更多
基金Project(52025082) supported by the National Natural Science Foundation for Distinguished Young Scholars of ChinaProject(CX20190288) supported by Hunan Provincial Innovation Foundation for Postgraduate,China。
文摘Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains,involving static aerodynamic forces and vortex-induced vibrations(VIVs).Static and dynamic sectional models of the girder and trains were employed for aerodynamic force measurement and VIV test,respectively.Results indicate that the aerodynamic interference effect on static aerodynamic forces of both the girder and trains is remarkable.When a single train exists,the horizontal position of the train has a small effect on aerodynamic coefficients of the girder.When two trains meet on the girder,the drag coefficient of the girder is significantly reduced compared with that of without train or with a single train;besides,during the whole meeting process,aerodynamic forces of the leeward train first drop and then increase suddenly.The fluctuation of aerodynamic force could cause redundant vibration of the train,which is unfavorable for safety and comfort.A train on the girder could worsen the girder VIV performance:a new vertical VIV appears in the triple-box girder when a train is on the girder,and the torsional VIV amplitude increases significantly when the train is on the windward side.
文摘The article design the hardware system scheme using STM32F407 as the control core circuit, and designed the software structure of the system and application layer multi task and priority based on transplanted μ C/OS operating system. Aimed at that the traditional drunk driving detection system has low sensitivity and unable to distinguish diffuse alcohol sigmal interference. For accurate identification of pilot and crew alcohol concentration, the paper puts forward a driving intelligent identification wine system based on embedded μC/OS- II. The experimental results show that the detection sensitivity of the system has high accuracy rate, effectively prevent the purpose for the prevention of drunk driving, drunk driving has very good practical value.
文摘The aim of the publication is to present the results of the research with the documents research method, involving studies of literature, legislation, and source acts on development of the system supporting the psychological tests （psychological tests battery） of the police drivers, including the privileged drivers of the police. The system, in its assumptions, should inter alia allow to make assessment of intellectual and psychomotor skills as well as personality （in accordance with the detailed guidelines of annex 6 to Regulation of the Minister of Health of 8 ]uly 2014 on the psychological tests of the vehicles drivers using the tools of proven accuracy, reliability above .7, objective, standardised, and normalised within a group of police drivers）. The described research is conducted based on the grant for realisation of the development project： ＂Development of Psychological Tests Supporting System of the Drivers for the Police＂, no. DOB-BIO7/20/01/2015. The method for the research of the documents in the form of indirect observation allowed to analyse the legal acts, both national and international, and the laws in force in the European Union.
文摘In the history of human space exploration, many failures of launch vehicles and spacecraft tare caused by vibration. At first, the periods in which the space products are in a vibration environment are discussed and the need for vibration testing is then introduced. As the main content of this paper, the current situation of shaker systems is elaborated in detail. In this part, electrodynamic shakers, as the most widely used vibration generators, are illustrated in detail including structures, principles and performances. Special inventions worldwide in the development of electrodynamic shakers such as induction ring shakers, high force shakers, multi-axial vibration testing systems and combined environmental testing systems are presented. At last, the recent progress and outlook of shaker systems are summarized.
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2013CB036203)the National Natural Science Foundation of China(Grant No.51308034)the"111"Project(Grant No.B13002)
文摘To investigate the aerodynamic effect of wind barriers on a high-speed train-bridge system,a sectional model test was conducted in a closed-circuit-type wind tunnel.Several different cases,including with and without barriers,with different barrier heights and porosity rates,and with different train arrangements on the bridge were taken into consideration;in addition,the aerodynamic coefficients of the train-bridge system were measured.It is found that the side force and rolling moment coefficients of the vehicle are efficiently reduced by a single-side wind barrier,but for the bridge deck these values are increased.The height and porosity rate of the barrier are two important factors that influence the windbreak effect.Train arrangement on the bridge will considerably influence the aerodynamic properties of the train-bridge system.The side force and rolling moment coefficients of the vehicle at the windward side are larger than at the leeward side.
