Magnetic Coupling of a Rotating Black Hole with Advection-Dominated Accretion Flows

A model of magnetic coupling (MC) of a rotating black hole (BH) with advection- dominated accretion flow (MCADAF) is proposed. It turns out that MCADAF providers a natural explanation for the transition radius between ADAF and SSD, and could be used to interpret the highest luminosity of GX 339-4 in hard-state. A very steep emissivity index can be produced in the innermost part of the MCADAF,which is consistent with the recent XMM-Newton observations of the nearby bright Seyfert 1 galaxy MCG-6-30-15 and with two X-ray binaries (XRBs): XTE J1655-500 and GX 339-4. In addition, we estimate the BH spins in Seyfert 1 galaxy MCG-6-30-15 and in the two XRBs based on this model.Comment: 18 pages, 9 figures,acceptted by New Astronom

A Study on Pulsed Power Supply based on Separate Excitation

© ASEE 2007Regular power supply cannot be used for some special applications such as discharging plasma generator, air purification system, medical discharging equipment, etc. Instead, a special low-power high-voltage pulsed power supply is required. In this paper, the design and simulation of a separate excited pulse power supply are proposed. The power supply can produce high-voltage small-current pulses adaptive to different loads. The working principle of the power supply is analyzed. A comparison between this power supply and other pulsed power supply based on capacitance energy storage is discussed. The circuit implementation of power supply is proposed. The key component for the power supply, pulse transformer, as well as other components is studied in detail. Based on the analysis, an optimized design of the power supply is proposed. Computer simulation is used to verify the performance of the designed power supply, such as the output characteristics under different load resistances, the pulse frequency and the duty ratio. Simulation results demonstrate the effectiveness of the designed power supply. Some possible performance improvements on the power supply are also suggested. The designed power supply can satisfy the requirements for commercial applications such as plasma generation and air purification system

Quantum correlation measure in arbitrary bipartite systems

A definition of quantum correlation is presented for an arbitrary bipartite quantum state based on the skew information. This definition not only inherits the good properties of skew information such as the contractivity and so on, but also is effective and almost analytically calculated for any bipartite quantum states. We also reveal the relation between our measure and quantum metrology. As applications, we give the exact expressions of quantum correlation for many states, which provides a direct support for our result.Comment: 6 pages, 2 figures. Comments are welcom

Terrestrial Locomotion of PogoX: From Hardware Design to Energy Shaping and Step-to-step Dynamics Based Control

We present a novel controller design on a robotic locomotor that combines an aerial vehicle with a spring-loaded leg. The main motivation is to enable the terrestrial locomotion capability on aerial vehicles so that they can carry heavy loads: heavy enough that flying is no longer possible, e.g., when the thrust-to-weight ratio (TWR) is small. The robot is designed with a pogo-stick leg and a quadrotor, and thus it is named as PogoX. We show that with a simple and lightweight spring-loaded leg, the robot is capable of hopping with TWR $<1$. The control of hopping is realized via two components: a vertical height control via control Lyapunov function-based energy shaping, and a step-to-step (S2S) dynamics based horizontal velocity control that is inspired by the hopping of the Spring-Loaded Inverted Pendulum (SLIP). The controller is successfully realized on the physical robot, showing dynamic terrestrial locomotion of PogoX which can hop at variable heights and different horizontal velocities with robustness to ground height variations and external pushes.Comment: 7 pages, 7 figure