The ordinary–slow extraordinary–Bernstein（O-SX-B） mode conversion in the electron cyclotron range of frequencies（ECRF） is revisited in slab geometry. The analytical formula of the O-SX conversion efficiency by M...The ordinary–slow extraordinary–Bernstein（O-SX-B） mode conversion in the electron cyclotron range of frequencies（ECRF） is revisited in slab geometry. The analytical formula of the O-SX conversion efficiency by Mj？lhus is upgraded to include the magnetic field gradient, and the analytical expression of the SX-B conversion efficiency by Ram and Schultz is generalized for the case of oblique injection. Therefore, the conversion efficiency and optimal parallel refractive index for the whole O-SX-B conversion are obtained analytically and a shift of optimal parallel refractive index due to SX-FX loss is found. Full wave calculations are also presented to be compared with the analytical results.展开更多
In this Letter, a sensor consisting of a fiber Bragg grating（FBG） and a fiber Fabry–Perot interferometer（FFPI）sensor is developed to measure the coefficient of thermal expansion（CTE） and the thermo-optical coef...In this Letter, a sensor consisting of a fiber Bragg grating（FBG） and a fiber Fabry–Perot interferometer（FFPI）sensor is developed to measure the coefficient of thermal expansion（CTE） and the thermo-optical coefficient（TOC） of a silica-based optical fiber at cryogenic temperatures. The FFPI is fabricated by welding together two acid-etched fibers. The temperature performance of the FFPI-FBG hybrid sensor is studied in the temperature range of 30–273 K. The CTE and TOC of the optical fiber at cryogenic temperatures are derived analytically and verified by experiments.展开更多
In the present study we investigate the 3-D hydrodynamic slamming problem on a vertical cylinder due to the impact of a steep wave that is moving with a steady velocity.The linear theory of the velocity potential is e...In the present study we investigate the 3-D hydrodynamic slamming problem on a vertical cylinder due to the impact of a steep wave that is moving with a steady velocity.The linear theory of the velocity potential is employed by assuming inviscid,incompressible fluid and irrotational flow.As the problem is set in 3-D space,the employment of the Wagner condition is essential.The set of equations we pose,is presented as a mixed boundary value problem for Laplace＇s equation in 3-D.Apart from the mixedtype of boundary conditions,the problem is complicated by considering that the region of wetted surface of the cylinder is a set whose boundary depends on the vertical coordinate on the cylinder up to the free-surface.We make some simple assumptions at the start but otherwise we proceed analytically.We find closed-form relations for the hydrodynamic variables,namely the time dependent potential,the pressure impulse,the shape of the wave front（from the contact point to beyond the cylinder） and the slamming force.展开更多
In order to deal with modeling problem of a pressure balance system with time-delay, nonlinear, time-varying and uncertain characteristics, an intelligent modeling procedure is proposed, which is based on artificial n...In order to deal with modeling problem of a pressure balance system with time-delay, nonlinear, time-varying and uncertain characteristics, an intelligent modeling procedure is proposed, which is based on artificial neural network(ANN) and input-output data of the system during shield tunneling and can overcome the precision problem in mechanistic modeling(MM) approach. The computational results show that the training algorithm with Gauss-Newton optimization has fast convergent speed. The experimental investigation indicates that, compared with mechanistic modeling approach, intelligent modeling procedure can obviously increase the precision in both soil pressure fitting and forecasting period. The effectiveness and accuracy of proposed intelligent modeling procedure are verified in laboratory tests.展开更多
In this paper,the thermal effects on the buckling of functionally graded（FG） nanobeams subjected to various types of thermal loading including uniform,linear and non-linear temperature changes are investigated based...In this paper,the thermal effects on the buckling of functionally graded（FG） nanobeams subjected to various types of thermal loading including uniform,linear and non-linear temperature changes are investigated based on the nonlocal third-order shear deformation beam theory.The material properties of FG nanobeam are supposed to vary gradually along the thickness direction according to the power-law form.The governing equations are derived through Hamilton＇s principle and solved analytically.Comparison examples are performed to verify the present results.Obtained results are presented for thermal buckling analysis of FG nanobeams such as the effects of the power-law index,nonlocal parameter,slenderness ratio and thermal loading in detail.展开更多
In this document,we analytically investigate fluid flow through a deformable tube.The fluid is considered to be Newtonian,incompressible and it moves along an elastic and isotropic tube wall.The study provides a revie...In this document,we analytically investigate fluid flow through a deformable tube.The fluid is considered to be Newtonian,incompressible and it moves along an elastic and isotropic tube wall.The study provides a review of recent modeling aimed at understanding the effects of fluid parameters over the elastic wall behavior.The unsteady fluid flow will be analyzed following the asymptotic approach process using to a large Reynolds number and a small aspect radio.Moreover,according to the small axisymmetric deformation,the wall is mathematically developed basing on the thin shell theory whose linear approach is applied.Lastly,the dynamic behavior of the tube is represented and discussed.展开更多
Let P and B be a polydisc and a ball in C^n respectively. Poincaré first pointed out that P was not equivalent analytically to B. Simha gave a new proof in terms of the Schwarz lemma in 1976. In this letter, we s...Let P and B be a polydisc and a ball in C^n respectively. Poincaré first pointed out that P was not equivalent analytically to B. Simha gave a new proof in terms of the Schwarz lemma in 1976. In this letter, we shall give another proof for this fact by using a property of the convex mappings on polydisc. Theorem. P is not equivalent analytically to B. Proof. If they were equivalent analytically, then there would exist an analytic and univalent mapping f which maps P onto B, i.e. f(P)=B. Let f(0)=0. Since B is a convex domain, by a theorem of Suffridge, there is a nonsingular matrix T, such展开更多
The galactic spiral structure seems to be a gaseous phenomenon, and therefore should be explained with the gaseous theory. After discussing the persistence and origin mechanism of the self-gravitationa galactic shock ...The galactic spiral structure seems to be a gaseous phenomenon, and therefore should be explained with the gaseous theory. After discussing the persistence and origin mechanism of the self-gravitationa galactic shock wave of the interstellar gas by the numerical method, it is necessary to study qualitatively the influenco of the perturbed gravitational field on the galactic shock wave by the analytical method. Moreover, galactic shock waves are generally studied by the numerical method[3-5], so it is necessary to do some discussion of it analytically.展开更多
本文提出一种适用于RF SOI工艺MOS变容管行为表征的新模型。提出的模型考虑了SOI衬底的物理特性,并给出了解析提取衬底寄生网络模型参数的方法。采用提出的模型,精确预见了RF SOI MOS变容管器件特性,测量和模型仿真结果,在20 GHz频率范...本文提出一种适用于RF SOI工艺MOS变容管行为表征的新模型。提出的模型考虑了SOI衬底的物理特性,并给出了解析提取衬底寄生网络模型参数的方法。采用提出的模型,精确预见了RF SOI MOS变容管器件特性,测量和模型仿真结果,在20 GHz频率范围内得到很好的吻合。展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.11325524 and 11261140327)Ministry of Science and Technology of China(Contract No.2013GB112001)
文摘The ordinary–slow extraordinary–Bernstein（O-SX-B） mode conversion in the electron cyclotron range of frequencies（ECRF） is revisited in slab geometry. The analytical formula of the O-SX conversion efficiency by Mj？lhus is upgraded to include the magnetic field gradient, and the analytical expression of the SX-B conversion efficiency by Ram and Schultz is generalized for the case of oblique injection. Therefore, the conversion efficiency and optimal parallel refractive index for the whole O-SX-B conversion are obtained analytically and a shift of optimal parallel refractive index due to SX-FX loss is found. Full wave calculations are also presented to be compared with the analytical results.
基金supported by the National High Technology Research and Development Program (No. 2012AA041203)the National Natural Science Foundation of China (No. 61307099)
文摘In this Letter, a sensor consisting of a fiber Bragg grating（FBG） and a fiber Fabry–Perot interferometer（FFPI）sensor is developed to measure the coefficient of thermal expansion（CTE） and the thermo-optical coefficient（TOC） of a silica-based optical fiber at cryogenic temperatures. The FFPI is fabricated by welding together two acid-etched fibers. The temperature performance of the FFPI-FBG hybrid sensor is studied in the temperature range of 30–273 K. The CTE and TOC of the optical fiber at cryogenic temperatures are derived analytically and verified by experiments.
文摘In the present study we investigate the 3-D hydrodynamic slamming problem on a vertical cylinder due to the impact of a steep wave that is moving with a steady velocity.The linear theory of the velocity potential is employed by assuming inviscid,incompressible fluid and irrotational flow.As the problem is set in 3-D space,the employment of the Wagner condition is essential.The set of equations we pose,is presented as a mixed boundary value problem for Laplace＇s equation in 3-D.Apart from the mixedtype of boundary conditions,the problem is complicated by considering that the region of wetted surface of the cylinder is a set whose boundary depends on the vertical coordinate on the cylinder up to the free-surface.We make some simple assumptions at the start but otherwise we proceed analytically.We find closed-form relations for the hydrodynamic variables,namely the time dependent potential,the pressure impulse,the shape of the wave front（from the contact point to beyond the cylinder） and the slamming force.
基金Project(2013CB035402) supported by the National Basic Research Program of ChinaProjects(51105048,51209028) supported by the National Natural Science Foundation of China
文摘In order to deal with modeling problem of a pressure balance system with time-delay, nonlinear, time-varying and uncertain characteristics, an intelligent modeling procedure is proposed, which is based on artificial neural network(ANN) and input-output data of the system during shield tunneling and can overcome the precision problem in mechanistic modeling(MM) approach. The computational results show that the training algorithm with Gauss-Newton optimization has fast convergent speed. The experimental investigation indicates that, compared with mechanistic modeling approach, intelligent modeling procedure can obviously increase the precision in both soil pressure fitting and forecasting period. The effectiveness and accuracy of proposed intelligent modeling procedure are verified in laboratory tests.
文摘In this paper,the thermal effects on the buckling of functionally graded（FG） nanobeams subjected to various types of thermal loading including uniform,linear and non-linear temperature changes are investigated based on the nonlocal third-order shear deformation beam theory.The material properties of FG nanobeam are supposed to vary gradually along the thickness direction according to the power-law form.The governing equations are derived through Hamilton＇s principle and solved analytically.Comparison examples are performed to verify the present results.Obtained results are presented for thermal buckling analysis of FG nanobeams such as the effects of the power-law index,nonlocal parameter,slenderness ratio and thermal loading in detail.
文摘In this document,we analytically investigate fluid flow through a deformable tube.The fluid is considered to be Newtonian,incompressible and it moves along an elastic and isotropic tube wall.The study provides a review of recent modeling aimed at understanding the effects of fluid parameters over the elastic wall behavior.The unsteady fluid flow will be analyzed following the asymptotic approach process using to a large Reynolds number and a small aspect radio.Moreover,according to the small axisymmetric deformation,the wall is mathematically developed basing on the thin shell theory whose linear approach is applied.Lastly,the dynamic behavior of the tube is represented and discussed.
文摘Let P and B be a polydisc and a ball in C^n respectively. Poincaré first pointed out that P was not equivalent analytically to B. Simha gave a new proof in terms of the Schwarz lemma in 1976. In this letter, we shall give another proof for this fact by using a property of the convex mappings on polydisc. Theorem. P is not equivalent analytically to B. Proof. If they were equivalent analytically, then there would exist an analytic and univalent mapping f which maps P onto B, i.e. f(P)=B. Let f(0)=0. Since B is a convex domain, by a theorem of Suffridge, there is a nonsingular matrix T, such
文摘The galactic spiral structure seems to be a gaseous phenomenon, and therefore should be explained with the gaseous theory. After discussing the persistence and origin mechanism of the self-gravitationa galactic shock wave of the interstellar gas by the numerical method, it is necessary to study qualitatively the influenco of the perturbed gravitational field on the galactic shock wave by the analytical method. Moreover, galactic shock waves are generally studied by the numerical method[3-5], so it is necessary to do some discussion of it analytically.
