In this paper, optical fluid is firstly defined. By using the movement law of hydrodynamics, the transverse coupling of waveguides is discussed. The result fully coincides with the electromagnetic solution.
A three-dimensional （3D） finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account.In this model,the displacement f...A three-dimensional （3D） finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account.In this model,the displacement formulation in Lagrange method,pressure formulation in Euler method,nonlinear contact model based on Coulomb friction law are applied to the air-cushion,reservoir and contraction joint domain,respectively.The dynamic response of Jinping I arch dam with a height of 305 m is analyzed using the seismic records of the Wenchuan Earthquake in 2008.Numerical results show that the air-cushion isolation reduces significantly the hydrodynamic pressure as well as the opening width for the contraction joints of high arch dam.展开更多
Machines are growth engines of the economy;each sector of the economy achieves its demand by the use of the machine. They are installed in various establishments for the purpose of using them to perform certain functi...Machines are growth engines of the economy;each sector of the economy achieves its demand by the use of the machine. They are installed in various establishments for the purpose of using them to perform certain functions or others. However, as a result of the kind of forces, dynamic and static loads, they transmitted to their adjoining surroundings when used, they are often mounted on supporting structures, foundations or a combination of them to achieve adequate or appropriate safe operation and stability. When a machine is operating, it is subjected to several time-varying forces and as a result of which it tends to exhibit vibrations. In such a situation or process, a certain quantity of this force is transmitted to the foundation, which could undermine the life of the foundation and also affect its performance and the operation of any other machines on the same foundation. Hence, it makes sense to minimize this force transmission. This research aimed at developing an adjustable steel-framed structure for supporting the major components of a 5.0 kW micro-steam power unit (steam, turbine and alternator) and evaluating the performance of the unit with or without the vibration isolator when they are axially connected with flexible flange coupling or transversely connected with sets of belts and pulleys, in succession, respectively. The results showed that reduction in the force transmitted to the supporting structure occurred when the vibration produced by the unit is isolated from its base by the use of a vibration isolator, maximum reduction of 99.95% achieved when axially coupled and 99.91% when transversely connected with belt and pulley system. The results also showed that better performance would be attained when the steam turbine is axially coupled to the alternator than when connected with belt and pulley;The maximum voltage of 52 V and speed of 1000 rpm at 77 dB sound level attained with coupling connection, and voltage of 20 V and speed of 752 rpm at 75 dB with belt and pulley connection.展开更多
BBU(Beam breakup)instability once appeared in the early stage of 'Dragon-Ⅰ' LIA,which was excited by TM_(110)mode stimulated when the eccentric beam passed through the multi-functional cavity(MFC).The radio f...BBU(Beam breakup)instability once appeared in the early stage of 'Dragon-Ⅰ' LIA,which was excited by TM_(110)mode stimulated when the eccentric beam passed through the multi-functional cavity(MFC).The radio frequency characteristics of MFC were analyzed with three methods such as analytic calculation,numerical computation,and measurement.The frequency of the TM_(110)mode from these methods agreed with the experimental results,while the transverse coupling impedance was different from the experimental results by some times.The main BBU exciter was the big transverse coupling impedance of the MFC which could be concluded.A grid was designed to shield the gap of the MFC.The experiments show that the BBU was compressed and the high frequency oscillation disappeared.展开更多
文摘In this paper, optical fluid is firstly defined. By using the movement law of hydrodynamics, the transverse coupling of waveguides is discussed. The result fully coincides with the electromagnetic solution.
基金supported by the National Natural Science Foun-dation of China (90715026)
文摘A three-dimensional （3D） finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account.In this model,the displacement formulation in Lagrange method,pressure formulation in Euler method,nonlinear contact model based on Coulomb friction law are applied to the air-cushion,reservoir and contraction joint domain,respectively.The dynamic response of Jinping I arch dam with a height of 305 m is analyzed using the seismic records of the Wenchuan Earthquake in 2008.Numerical results show that the air-cushion isolation reduces significantly the hydrodynamic pressure as well as the opening width for the contraction joints of high arch dam.
文摘Machines are growth engines of the economy;each sector of the economy achieves its demand by the use of the machine. They are installed in various establishments for the purpose of using them to perform certain functions or others. However, as a result of the kind of forces, dynamic and static loads, they transmitted to their adjoining surroundings when used, they are often mounted on supporting structures, foundations or a combination of them to achieve adequate or appropriate safe operation and stability. When a machine is operating, it is subjected to several time-varying forces and as a result of which it tends to exhibit vibrations. In such a situation or process, a certain quantity of this force is transmitted to the foundation, which could undermine the life of the foundation and also affect its performance and the operation of any other machines on the same foundation. Hence, it makes sense to minimize this force transmission. This research aimed at developing an adjustable steel-framed structure for supporting the major components of a 5.0 kW micro-steam power unit (steam, turbine and alternator) and evaluating the performance of the unit with or without the vibration isolator when they are axially connected with flexible flange coupling or transversely connected with sets of belts and pulleys, in succession, respectively. The results showed that reduction in the force transmitted to the supporting structure occurred when the vibration produced by the unit is isolated from its base by the use of a vibration isolator, maximum reduction of 99.95% achieved when axially coupled and 99.91% when transversely connected with belt and pulley system. The results also showed that better performance would be attained when the steam turbine is axially coupled to the alternator than when connected with belt and pulley;The maximum voltage of 52 V and speed of 1000 rpm at 77 dB sound level attained with coupling connection, and voltage of 20 V and speed of 752 rpm at 75 dB with belt and pulley connection.
文摘BBU(Beam breakup)instability once appeared in the early stage of 'Dragon-Ⅰ' LIA,which was excited by TM_(110)mode stimulated when the eccentric beam passed through the multi-functional cavity(MFC).The radio frequency characteristics of MFC were analyzed with three methods such as analytic calculation,numerical computation,and measurement.The frequency of the TM_(110)mode from these methods agreed with the experimental results,while the transverse coupling impedance was different from the experimental results by some times.The main BBU exciter was the big transverse coupling impedance of the MFC which could be concluded.A grid was designed to shield the gap of the MFC.The experiments show that the BBU was compressed and the high frequency oscillation disappeared.
