Objective:Pectus excavatum(PE)is the most frequently observed congenital deformity of the chest with a deep depression of the sternum in the anterior thoracic *** more than 20%of pectus excavatum patients were reporte...
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Objective:Pectus excavatum(PE)is the most frequently observed congenital deformity of the chest with a deep depression of the sternum in the anterior thoracic *** more than 20%of pectus excavatum patients were reported to have *** to now,no comprehensive analysis about the impact that pectus excavatum has on scoliosis has been performed,although previous research has involved correlation among scoli-
La2O3 films are grown on Si （100） substrates by the radio-frequency magnetron sputtering technique. The band alignment of the La203/Si heterojunction is analyzed by the x-ray photoelectron spectroscopy. The valence-...
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La2O3 films are grown on Si （100） substrates by the radio-frequency magnetron sputtering technique. The band alignment of the La203/Si heterojunction is analyzed by the x-ray photoelectron spectroscopy. The valence- band and the conduction-band offsets of La2 Oa films to Si substrates are found to be 2.40±0.1 and 1.66±0.3 eV, respectively. Based on 0 ls energy loss spectrum analysis, it can be noted that the energy gap of La203 films is 5.18±0.2eV, which is confirmed by the ultra-violet visible spectrum. According to the suitable band offset and large band gap, it can be concluded that La2O3 could be a promising candidate to act as high-k gate dielectrics.
Since the heat dissipation problemis harsh in high power LED lamp, in our studywe suggest an optimal design method of high-power LED lamps radiator based on the equivalent thermal circuit method, we abstract mathemati...
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Since the heat dissipation problemis harsh in high power LED lamp, in our studywe suggest an optimal design method of high-power LED lamps radiator based on the equivalent thermal circuit method, we abstract mathematical model of the heat dissipation system of the lamps, then chose several key parameters of radiator--spacing of fins S, height of fins H, thickness of fins t and number of Micro Heat Pipe ArrayN Has design parameters, and set minimum temperature of the chips as optimization objective. Based on the optimization algorithm we have mentioned, we designed a new radiator for high power LED lamps, through steady-heat-thermal analysis in ANSYS software, the junction temperature is far below the requirement. Therefore, the optimization algorithm can be effectively applied to radiator design of high power LED devices with the advantage of accuracy and swiftness.
This paper presents a straightforward and systematical methodology for conducting the inverse dynamic analysis of a 3-prismatic-universal-universal (PUU) parallel kinematic manipulator (PKM) through employing the prin...
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ISBN:
(纸本)9781467391085
This paper presents a straightforward and systematical methodology for conducting the inverse dynamic analysis of a 3-prismatic-universal-universal (PUU) parallel kinematic manipulator (PKM) through employing the principle of virtual work. The proposed 3-PUU PKM possesses three translational degree-of-freedom (DOF). The position, velocity and acceleration of joints are solved via the inverse kinematic analysis, the link Jacobian matrices which map the velocity of the moving platform into the velocity and angular velocity of struts are derived in the fixed coordinate system. Based on the d'Alembert's form of the principle of virtual work, the applied generalized forces of the whole mechanical system are divided into the applied forces of moving platform, struts, sliders, and motor-coupling-leadscrew, respectively. The joint actuated torques are obtained through eliminating the virtual displacement in the dynamic equations. Furthermore, the inertial term, centrifugal and Coriolis term, and gravitational term of the total joint torque are determined. Simulation for a conical spiral trajectory demonstrates that the total torque is dominated by the inertial term.
A widely tunable high precision chaotic fiber laser is proposed and experimentally demonstrated.A tunable fiber Bragg grating(TFBG) filter is used as a tuning element to determine the turning range from 1533 nm to 155...
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A widely tunable high precision chaotic fiber laser is proposed and experimentally demonstrated.A tunable fiber Bragg grating(TFBG) filter is used as a tuning element to determine the turning range from 1533 nm to 1558 nm with a linewidth of 0.5 nm at any *** wide tuning range is capable of supporting 32 wavelength-division multiplexing(WDM) channels with 100 GHz channel *** single wavelengths are found to be chaotic with 10 GHz *** full width at half maximum(FWHM) of the chaotic correlation curve of the different wavelengths is on a picosecond time scale,thereby offering millimeter spatial resolution in WDM detection.
A novel parallel micromanipulator with large range of motion based on flexible hinges is designed and analyzed in this paper, which has three degrees of freedom motions along x, y and z axes. The Pseudo-Rigid-Body (PR...
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ISBN:
(纸本)9781467391085
A novel parallel micromanipulator with large range of motion based on flexible hinges is designed and analyzed in this paper, which has three degrees of freedom motions along x, y and z axes. The Pseudo-Rigid-Body (PRB) model method is applied to obtain the kinetic performance and inputting stiffness. To calculate the natural frequency of the mechanism, the Lagrange method is used to achieve the dynamic and frequency equations. In addition, the working range of the architecture is also calculated, analyzed and compared with other similar structures by using ANSYS software, our designed micromanipulator has larger workspace than other existed stages.
The reaction-diffusion neural network is often described by semilinear diffusion partial differential equation (PDE). This article focuses on the asymptotical synchronization and synchronization for coupled reaction-d...
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In this paper, a passivity-based synchronization method is proposed for a new hyperchaotic Lorenz system based on Lyapunov stability theory and linear matrix inequality (LMI) approach. On the basis of the property of ...
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ISBN:
(纸本)9781467373395
In this paper, a passivity-based synchronization method is proposed for a new hyperchaotic Lorenz system based on Lyapunov stability theory and linear matrix inequality (LMI) approach. On the basis of the property of the passive system, the passive controller is designed and synchronization of two identical new hyperchaotic Lorenz systems with different initial conditions is realized. Finally, numerical simulations are presented to demonstrate the effectiveness of the proposed chaos control and synchronization schemes.
Due to the continuing action of alternating loads, the micro defects of rotor's materials and the micro traumas in the mechanic processing will easily cause the crack propagation and even the catastrophic accident...
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ISBN:
(纸本)9781479970995
Due to the continuing action of alternating loads, the micro defects of rotor's materials and the micro traumas in the mechanic processing will easily cause the crack propagation and even the catastrophic accidents. The vibration characteristics of the rotor system, the crack breathing states and the crack breathing periods are investigated with different parameters of the synchronous state through the numerical simulation, which are all based on the dynamic model of the nonlinear cracked rotor and the describing function of the breathing crack. The crack breathing states are also studied under the asynchronous state. The paper proposes a novel method of the delaying crack propagation using an Electro-Magnetic Actuator (EMA) in order to realize the vibration control and the delaying crack propagation. By comparing influences of the crack breathing state caused by changes of different parameters (rotational speed, crack angle, crack depth and nonlinear parameters, etc.), the paper summarizes the mutation regulations of the crack breathing state in the synchronous and verifies the feasibility of delaying the crack propagation mechanism. The result of the research shows that the EMA can control the vibration of the nonlinear cracked rotor and delay the crack propagation in the running process of the nonlinear cracked rotor.
This paper presents a systematic and comprehensive modeling approach for the derivation of a nonlinear dynamic model of a unmanned aerial vehicle (UAV) quadrotor. The model incorporates a couple of significant aerodyn...
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ISBN:
(纸本)9781467391054
This paper presents a systematic and comprehensive modeling approach for the derivation of a nonlinear dynamic model of a unmanned aerial vehicle (UAV) quadrotor. The model incorporates a couple of significant aerodynamic effects impacting on the quadrotor flight in different regimes. The controller is accordingly designed to accommodate both specific and uncertain dynamics of the quadrotor. The control laws of linear quadratic regulator (LQR) coupled with sliding mode control (SMC) are applied to the controller design so as to perform the optimal and robust control of the vehicle. The experimental results demonstrate the designed control algorithms are capable of delivering an remarkable performance on tracking of the reference input signals.
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