The new type of torsional angle transformer-quarter-wave length hyperbolic secant taper was derived in which the maximum point of surface shear stress is inexistent. The half-wave length complex horns can be composed ...The new type of torsional angle transformer-quarter-wave length hyperbolic secant taper was derived in which the maximum point of surface shear stress is inexistent. The half-wave length complex horns can be composed on the basis of the new taper and quarter-wave taper which may be cylindrical exponential, sirnilar-catenary or similar-cosinc. The resonant frequency and angle amplification ratio of some complex transformers were measured. The experimental results basically agree with the theoretical values. The complex horns have a serics of good characteristics, such as the amplification ratio is very large, the changc of input impedance with the deviation of the frequency is little, the maximum output ultrasonic power is much higher than that of other types of the same material. Therefore, they are very useful horns in high-intensity ultrasonic field.展开更多
A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes ...A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes two nonlinear terms caused by finite deformation and double geometric dispersion effects caused by transverse inertia and transverse shearing strain. Nonlinear wave equation and corresponding truncated nonlinear wave equation were solved by the hyperbolic secant function finite expansion method. The solitary wave solutions of these nonlinear equations were obtained. The necessary condition of these solutions existence was given also.展开更多
Effects of oblique collisions of the dust acoustic(DA)waves in dusty plasma are studied by considering unmagnetized fully ionized plasma.The plasma consists of inertial warm negatively charged massive dusts,positively...Effects of oblique collisions of the dust acoustic(DA)waves in dusty plasma are studied by considering unmagnetized fully ionized plasma.The plasma consists of inertial warm negatively charged massive dusts,positively charged dusts,superthermal kappa distributed electrons,and isothermal ions.The extended Poincaré–Lighthill–Kuo(e PLK)method is employed for the drivation of two-sided Korteweg–de Vries(KdV)equations(KdVEs).The Kd V soliton solutions are derived by using the hyperbolic secant method.The effects of superthermality index of electrons,temperature ratio of isothermal ion to electron,and the density ratio of isothermal ions to negatively charged massive dusts on nonlinear coefficients are investigated.The effects of oblique collision on amplitude,phase shift,and potential profile of right traveling solitons of DA waves are also studied.The study reveals that the new nonlinear wave structures are produced in the colliding region due to head-on collision of the two counter propagating DA waves.The nonlinearity is found to decrease with the increasing density ratio of ion to negative dust in the critical region.The phase shifts decrease(increase)with increasing the temperature ratio of ion to electron(κe).The hump(compressive,κe<κec)and dipshaped(rarefactive,κe>κec)solitons are produced depending on the angle(θ)of oblique collision between the two waves.展开更多
文摘The new type of torsional angle transformer-quarter-wave length hyperbolic secant taper was derived in which the maximum point of surface shear stress is inexistent. The half-wave length complex horns can be composed on the basis of the new taper and quarter-wave taper which may be cylindrical exponential, sirnilar-catenary or similar-cosinc. The resonant frequency and angle amplification ratio of some complex transformers were measured. The experimental results basically agree with the theoretical values. The complex horns have a serics of good characteristics, such as the amplification ratio is very large, the changc of input impedance with the deviation of the frequency is little, the maximum output ultrasonic power is much higher than that of other types of the same material. Therefore, they are very useful horns in high-intensity ultrasonic field.
基金Project supported by the National Natural Science Foundation of China (No.10472076)the Natural Science Foundation of Shanxi Province of China (No.2006021005)
文摘A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes two nonlinear terms caused by finite deformation and double geometric dispersion effects caused by transverse inertia and transverse shearing strain. Nonlinear wave equation and corresponding truncated nonlinear wave equation were solved by the hyperbolic secant function finite expansion method. The solitary wave solutions of these nonlinear equations were obtained. The necessary condition of these solutions existence was given also.
文摘Effects of oblique collisions of the dust acoustic(DA)waves in dusty plasma are studied by considering unmagnetized fully ionized plasma.The plasma consists of inertial warm negatively charged massive dusts,positively charged dusts,superthermal kappa distributed electrons,and isothermal ions.The extended Poincaré–Lighthill–Kuo(e PLK)method is employed for the drivation of two-sided Korteweg–de Vries(KdV)equations(KdVEs).The Kd V soliton solutions are derived by using the hyperbolic secant method.The effects of superthermality index of electrons,temperature ratio of isothermal ion to electron,and the density ratio of isothermal ions to negatively charged massive dusts on nonlinear coefficients are investigated.The effects of oblique collision on amplitude,phase shift,and potential profile of right traveling solitons of DA waves are also studied.The study reveals that the new nonlinear wave structures are produced in the colliding region due to head-on collision of the two counter propagating DA waves.The nonlinearity is found to decrease with the increasing density ratio of ion to negative dust in the critical region.The phase shifts decrease(increase)with increasing the temperature ratio of ion to electron(κe).The hump(compressive,κe<κec)and dipshaped(rarefactive,κe>κec)solitons are produced depending on the angle(θ)of oblique collision between the two waves.
