The black hole model will be excluded by a very strong radial magnetic field near the Galactic Center which has been detected in 2013. Following it, the explosion mechanism, for both supernova and the hot big bang of ...The black hole model will be excluded by a very strong radial magnetic field near the Galactic Center which has been detected in 2013. Following it, the explosion mechanism, for both supernova and the hot big bang of the Universe, driven by magnetic monopoles is proposed in this paper.展开更多
基于弯曲波在声黑洞(acoustic black hole,ABH)结构中振幅不断增大的特性,提出了一种新型径向夹心式径-弯复合换能器,该换能器由径向夹心式圆环换能器与外围的环形ABH结构组成.ABH结构的存在实现了换能器径向振动与弯曲振动之间的转换,...基于弯曲波在声黑洞(acoustic black hole,ABH)结构中振幅不断增大的特性,提出了一种新型径向夹心式径-弯复合换能器,该换能器由径向夹心式圆环换能器与外围的环形ABH结构组成.ABH结构的存在实现了换能器径向振动与弯曲振动之间的转换,提高了换能器的声辐射性能.利用几何声学的方法建立了ABH结构弯曲振动的解析模型,给出了其弯曲振动的本征频率,并结合有限元方法讨论了换能器机电转换性能随尺寸变化的关系.通过有限元方法给出了该换能器在空气中的辐射声压场、辐射声强以及辐射指向性,仿真结果表明,ABH结构的存在能够改善换能器弯曲振动的机电转换性能,提高换能器的声辐射性能,使换能器呈现出一定的辐射指向性.最后通过实验对换能器样机的电阻抗特性以及振动模态进行测量,实验结果与仿真相符合.展开更多
The present paper deals with spherically symmetric deformation of an inclusion- matrix problem, which consists of an infinite isotropic matrix and a spherically uniform anisotropic piezoelectric inclusion. The interfa...The present paper deals with spherically symmetric deformation of an inclusion- matrix problem, which consists of an infinite isotropic matrix and a spherically uniform anisotropic piezoelectric inclusion. The interface between the two phases is supposed to be perfect and the system is subjected to uniform loadings at infinity. Exact solutions are obtained for solid spherical piezoelectric inclusion and isotropic matrix. When the system is subjected to a remote traction, analytical results show that remarkable nature exists in the spherical inclusion. It is demonstrated that an infinite stress appears at the center of the inclusion. Furthermore, a cavitation may occur at the center of the inclusion when the system is subjected to uniform tension, while a black hole may be formed at the center of the inclusion when the applied traction is uniform pressure. The appearance of different remarkable nature depends only on one non-dimensional material parameter and the type of the remote traction, while is independent of the magnitude of the traction.展开更多
A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described...A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes density and photocurrent are found. The wavelength and structural parameters (base radius, emitter thickness) influences on charge carriers density and photocurrent are shown and examined.展开更多
文摘The black hole model will be excluded by a very strong radial magnetic field near the Galactic Center which has been detected in 2013. Following it, the explosion mechanism, for both supernova and the hot big bang of the Universe, driven by magnetic monopoles is proposed in this paper.
文摘基于弯曲波在声黑洞(acoustic black hole,ABH)结构中振幅不断增大的特性,提出了一种新型径向夹心式径-弯复合换能器,该换能器由径向夹心式圆环换能器与外围的环形ABH结构组成.ABH结构的存在实现了换能器径向振动与弯曲振动之间的转换,提高了换能器的声辐射性能.利用几何声学的方法建立了ABH结构弯曲振动的解析模型,给出了其弯曲振动的本征频率,并结合有限元方法讨论了换能器机电转换性能随尺寸变化的关系.通过有限元方法给出了该换能器在空气中的辐射声压场、辐射声强以及辐射指向性,仿真结果表明,ABH结构的存在能够改善换能器弯曲振动的机电转换性能,提高换能器的声辐射性能,使换能器呈现出一定的辐射指向性.最后通过实验对换能器样机的电阻抗特性以及振动模态进行测量,实验结果与仿真相符合.
基金the National Natural Science Foundation of China (Nos. 10702077, 10602001 and 10672001)the Beijing Natural Science Foundation (No. 1083012).
文摘The present paper deals with spherically symmetric deformation of an inclusion- matrix problem, which consists of an infinite isotropic matrix and a spherically uniform anisotropic piezoelectric inclusion. The interface between the two phases is supposed to be perfect and the system is subjected to uniform loadings at infinity. Exact solutions are obtained for solid spherical piezoelectric inclusion and isotropic matrix. When the system is subjected to a remote traction, analytical results show that remarkable nature exists in the spherical inclusion. It is demonstrated that an infinite stress appears at the center of the inclusion. Furthermore, a cavitation may occur at the center of the inclusion when the system is subjected to uniform tension, while a black hole may be formed at the center of the inclusion when the applied traction is uniform pressure. The appearance of different remarkable nature depends only on one non-dimensional material parameter and the type of the remote traction, while is independent of the magnitude of the traction.
文摘A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes density and photocurrent are found. The wavelength and structural parameters (base radius, emitter thickness) influences on charge carriers density and photocurrent are shown and examined.
