An electric-arc plasma installation operated in the hidden anode arrangement is constructed and used for the preparation of carbon nanostructures. A contracted plasma arc generated by a plasma torch using an inert gas...An electric-arc plasma installation operated in the hidden anode arrangement is constructed and used for the preparation of carbon nanostructures. A contracted plasma arc generated by a plasma torch using an inert gas is used as heat source. The average mass temperature of arc is higher than 10^4 K, while its power density, which is directly transferred onto the electrode （anode）, is - 2 kW/mm^2. The anode contact area formed on the electrode moves against the arc by way of shifting the electrode and is hidden completely in the interior of plasma gas stream moving towards it. As a result of both the direct plasma attack and the opposite movement of streams in the hidden anode contact area, a temperature higher than 6000 K is reached. Thus, intensive vaporization takes place, which forms a saturated plasma-gas-aerosol phase of the initial material of electrode （anode）. This gas phase is mixed in and carried by the plasma stream. Over that mixed plasma stream, a controlled process of quenching （fixation） is carried out by twisted turbulent fluid streams. After the fixation, the resultant carbon nano-structures are caught by a filter and collected in a bunker.展开更多
The results of design and experiment of a submerged semi-circular breakwater at the Yangtze estuary show that the submerged structure will be unsafe when the general empirical wave force formula for semi-circular brea...The results of design and experiment of a submerged semi-circular breakwater at the Yangtze estuary show that the submerged structure will be unsafe when the general empirical wave force formula for semi-circular breakwater is used in design. Therefore, a new calculation method for the wave forces acting on a submerged semi-circular structure is given in this paper, in which the wave force acting on the inside circumference of semi-circular arch is included, and the phase modification coefficient in the general empirical formula is adjusted as well. The new wave force calculation method has been Verified by the results of seven related physical model tests and adopted in the design of the south esturary jetty of the first stage project of Deep Channel Improvement Project of the Yangtze River Estuary, the total jetty length being 17.5 km.展开更多
This paper proposes an approach to extract the mode shapes of beam-like structures from the dynamic response of a moving mass. When a mass passes through a beam containing several artificially installed humps, its ver...This paper proposes an approach to extract the mode shapes of beam-like structures from the dynamic response of a moving mass. When a mass passes through a beam containing several artificially installed humps, its vertical acceleration can be recorded. After applying fast Fourier transformation to the dynamic response, one can extract the mode shapes of the beam. The surface roughness was neglected compared to the humps and its adverse effect on the extraction was reduced. The passing mass performs as both “exciter” and “massage receiver”;therefore, this method requires only one single accelerometer, making it more convenient and time saving in practice. Moreover, to estimate the possible error in extracting mode shapes, a wavenumber domain filtering technique is used to reconstruct the general profiles of mode shapes. Experimental validation of this approach in laboratory scale was conducted. The experimental results show that the proposed method performs well in extracting lower order mode shapes. It should also be noted that the passing mass can not have a very high velocity (e.g. 80 mm/s), otherwise the mass may jump and separate from the beam, and the proposed method may fail to identify mode shapes.展开更多
The uplift resistance calculation is an important basis for the construction decisions of the jack-up wind installation vessel and the design of the jacking system,and determines the operation risk and reliability in ...The uplift resistance calculation is an important basis for the construction decisions of the jack-up wind installation vessel and the design of the jacking system,and determines the operation risk and reliability in the installation process of the wind turbine. The influence factors of the pile shoe's penetration depth and uplift resistance are analyzed,and the calculation model and flow of the uplift resistance are given. Based on a construction example,the influence rules are analyzed for the change of the pile shoe's structural parameters on the penetration depth and uplift resistance.The analysis results show that the penetration depth is more sensitive to the width of the pile shoe,and the height has greater influence on the uplift resistance than the length and width of the spud. With the increase of the height,the uplift resistance may increase rapidly.Although the decreases of the length,width and height of the pile shoe may reduce the uplift resistance,the penetration depth may increase in the meantime. This will increase the pulling pile time and reduce the construction efficiency. So the parameters of the pile shoe should be optimized according to the adaptable geology condition so as to obtain the optimal uplift resistance and working efficiency.展开更多
The Liujiaxia Bridge is 536 m span steel truss stiffening Girder Bridge, tower with double-column steel concrete slructure, which is the world＇s largest diameter, the largest steel plate thickness of concrete pylon. ...The Liujiaxia Bridge is 536 m span steel truss stiffening Girder Bridge, tower with double-column steel concrete slructure, which is the world＇s largest diameter, the largest steel plate thickness of concrete pylon. Sarasota manufactured using standard pipe segment, group fight scene segment piecewise hoisting tower segment perfusion within the micro-expansion concrete construction technology, tower maximum height of 61.5 meters. This paper describes a piecewise Sarasota steel installation, piecewise perfusion within the micro-expansion concrete tower new construction method - attached to a self-climbing tower bridge ganlry crane mounted pylon construction technology of large steel components. Of the ＂entity attached to the pylon installation of equipment by section climb＂ design, composition and construction applications are described in detail.展开更多
文摘An electric-arc plasma installation operated in the hidden anode arrangement is constructed and used for the preparation of carbon nanostructures. A contracted plasma arc generated by a plasma torch using an inert gas is used as heat source. The average mass temperature of arc is higher than 10^4 K, while its power density, which is directly transferred onto the electrode （anode）, is - 2 kW/mm^2. The anode contact area formed on the electrode moves against the arc by way of shifting the electrode and is hidden completely in the interior of plasma gas stream moving towards it. As a result of both the direct plasma attack and the opposite movement of streams in the hidden anode contact area, a temperature higher than 6000 K is reached. Thus, intensive vaporization takes place, which forms a saturated plasma-gas-aerosol phase of the initial material of electrode （anode）. This gas phase is mixed in and carried by the plasma stream. Over that mixed plasma stream, a controlled process of quenching （fixation） is carried out by twisted turbulent fluid streams. After the fixation, the resultant carbon nano-structures are caught by a filter and collected in a bunker.
文摘The results of design and experiment of a submerged semi-circular breakwater at the Yangtze estuary show that the submerged structure will be unsafe when the general empirical wave force formula for semi-circular breakwater is used in design. Therefore, a new calculation method for the wave forces acting on a submerged semi-circular structure is given in this paper, in which the wave force acting on the inside circumference of semi-circular arch is included, and the phase modification coefficient in the general empirical formula is adjusted as well. The new wave force calculation method has been Verified by the results of seven related physical model tests and adopted in the design of the south esturary jetty of the first stage project of Deep Channel Improvement Project of the Yangtze River Estuary, the total jetty length being 17.5 km.
文摘This paper proposes an approach to extract the mode shapes of beam-like structures from the dynamic response of a moving mass. When a mass passes through a beam containing several artificially installed humps, its vertical acceleration can be recorded. After applying fast Fourier transformation to the dynamic response, one can extract the mode shapes of the beam. The surface roughness was neglected compared to the humps and its adverse effect on the extraction was reduced. The passing mass performs as both “exciter” and “massage receiver”;therefore, this method requires only one single accelerometer, making it more convenient and time saving in practice. Moreover, to estimate the possible error in extracting mode shapes, a wavenumber domain filtering technique is used to reconstruct the general profiles of mode shapes. Experimental validation of this approach in laboratory scale was conducted. The experimental results show that the proposed method performs well in extracting lower order mode shapes. It should also be noted that the passing mass can not have a very high velocity (e.g. 80 mm/s), otherwise the mass may jump and separate from the beam, and the proposed method may fail to identify mode shapes.
基金Department of Transportation Technology of Construction Project,China(No.2013328225080)Natural Science Foundation of Liaoning Province,China(No.2015020121)the Fundamental Research Funds for the Central Universities,China(Nos.3132015087,3132014303)
文摘The uplift resistance calculation is an important basis for the construction decisions of the jack-up wind installation vessel and the design of the jacking system,and determines the operation risk and reliability in the installation process of the wind turbine. The influence factors of the pile shoe's penetration depth and uplift resistance are analyzed,and the calculation model and flow of the uplift resistance are given. Based on a construction example,the influence rules are analyzed for the change of the pile shoe's structural parameters on the penetration depth and uplift resistance.The analysis results show that the penetration depth is more sensitive to the width of the pile shoe,and the height has greater influence on the uplift resistance than the length and width of the spud. With the increase of the height,the uplift resistance may increase rapidly.Although the decreases of the length,width and height of the pile shoe may reduce the uplift resistance,the penetration depth may increase in the meantime. This will increase the pulling pile time and reduce the construction efficiency. So the parameters of the pile shoe should be optimized according to the adaptable geology condition so as to obtain the optimal uplift resistance and working efficiency.
文摘The Liujiaxia Bridge is 536 m span steel truss stiffening Girder Bridge, tower with double-column steel concrete slructure, which is the world＇s largest diameter, the largest steel plate thickness of concrete pylon. Sarasota manufactured using standard pipe segment, group fight scene segment piecewise hoisting tower segment perfusion within the micro-expansion concrete construction technology, tower maximum height of 61.5 meters. This paper describes a piecewise Sarasota steel installation, piecewise perfusion within the micro-expansion concrete tower new construction method - attached to a self-climbing tower bridge ganlry crane mounted pylon construction technology of large steel components. Of the ＂entity attached to the pylon installation of equipment by section climb＂ design, composition and construction applications are described in detail.
