The laser induced plasma dynamics of graphite material are investigated by optical emission spectroscopy. Abla- tion and excitation of the graphite material is performed by using an 1064nm Nd：YAG laser in different a...The laser induced plasma dynamics of graphite material are investigated by optical emission spectroscopy. Abla- tion and excitation of the graphite material is performed by using an 1064nm Nd：YAG laser in different ambient pressures. Characteristics of graphite spectra as line intensity variations and signal-to-noise ratio are presented with a main focus on the influence of the ambient pressure on the interaction of laser-induced graphite plasma with an ambient environment. Atomic emission lines are utilized to investigate the dynamical behavior of plasma, such as the excitation temperature and electron density, to describe emission differences under different ambient conditions. The excitation temperature and plasma electron density are the primary factors which contribute to the differences among the atomic carbon emission at different ambient pressures. Reactions between the plasma species and ambient gas, and the total molecular number are the main factors influencing molecular carbon emis- sion. The influence of laser energy on the plasma interaction with environment is also investigated to demonstrate the dynamical behavior of carbon species so that it can be utilized to optimize plasma fluctuations.展开更多
For sustainable tourism, a novel method of security camera operation is proposed. In the method, security cameras, which encrypt the taken images and store them into the memory card inside, are used. Only when crimes ...For sustainable tourism, a novel method of security camera operation is proposed. In the method, security cameras, which encrypt the taken images and store them into the memory card inside, are used. Only when crimes occur, the memory cards are taken out from the cameras and the images are decrypted with the key and viewed by the city government and/or the police. When no crimes occur, images are overwritten by the new ones after a week automatically without being viewed by anyone. By using the stand-alone cameras without wiring to the control center, the installation cost and the operation cost are much lower than CCTV cameras. By using image encryption, the privacy of the tourists is protected. Using this system, high density installation of the security cameras with very low cost can be realized in encryption with image encryption privacy protection展开更多
We propose a novel system of a broadband source generation using a common soliton pulse (i.e. with center wavelength at 1.55 ?m) propagating within a nonlinear microring and nanoring resonators system. A system consis...We propose a novel system of a broadband source generation using a common soliton pulse (i.e. with center wavelength at 1.55 ?m) propagating within a nonlinear microring and nanoring resonators system. A system consists of a micro ring resonator system incorporating an add/drop filter, whereas the large bandwidth signals can be generated, stored and regenerated within the system. By using the appropriate parameters relating to the practical device such as micro ring radii, coupling coefficients, linear and nonlinear refractive index, we found that the obtained multi soliton pulses have shown the potential of application for dense wavelength division application, whereas the different center wavelengths of the soliton bands can be obtained via the add/drop filter, which can be used to increase the channel capacity in communication network.展开更多
基金Supported by the FRGS under Grant No R.J130000.7809.4F519
文摘The laser induced plasma dynamics of graphite material are investigated by optical emission spectroscopy. Abla- tion and excitation of the graphite material is performed by using an 1064nm Nd：YAG laser in different ambient pressures. Characteristics of graphite spectra as line intensity variations and signal-to-noise ratio are presented with a main focus on the influence of the ambient pressure on the interaction of laser-induced graphite plasma with an ambient environment. Atomic emission lines are utilized to investigate the dynamical behavior of plasma, such as the excitation temperature and electron density, to describe emission differences under different ambient conditions. The excitation temperature and plasma electron density are the primary factors which contribute to the differences among the atomic carbon emission at different ambient pressures. Reactions between the plasma species and ambient gas, and the total molecular number are the main factors influencing molecular carbon emis- sion. The influence of laser energy on the plasma interaction with environment is also investigated to demonstrate the dynamical behavior of carbon species so that it can be utilized to optimize plasma fluctuations.
文摘For sustainable tourism, a novel method of security camera operation is proposed. In the method, security cameras, which encrypt the taken images and store them into the memory card inside, are used. Only when crimes occur, the memory cards are taken out from the cameras and the images are decrypted with the key and viewed by the city government and/or the police. When no crimes occur, images are overwritten by the new ones after a week automatically without being viewed by anyone. By using the stand-alone cameras without wiring to the control center, the installation cost and the operation cost are much lower than CCTV cameras. By using image encryption, the privacy of the tourists is protected. Using this system, high density installation of the security cameras with very low cost can be realized in encryption with image encryption privacy protection
文摘We propose a novel system of a broadband source generation using a common soliton pulse (i.e. with center wavelength at 1.55 ?m) propagating within a nonlinear microring and nanoring resonators system. A system consists of a micro ring resonator system incorporating an add/drop filter, whereas the large bandwidth signals can be generated, stored and regenerated within the system. By using the appropriate parameters relating to the practical device such as micro ring radii, coupling coefficients, linear and nonlinear refractive index, we found that the obtained multi soliton pulses have shown the potential of application for dense wavelength division application, whereas the different center wavelengths of the soliton bands can be obtained via the add/drop filter, which can be used to increase the channel capacity in communication network.
