The surface modification of materials such as Ti-6Al-4V is necessary to improve their wear resistant properties for use in tribological applications. In this paper it is shown that a laser with low power and tungsten ...The surface modification of materials such as Ti-6Al-4V is necessary to improve their wear resistant properties for use in tribological applications. In this paper it is shown that a laser with low power and tungsten inert gas (TIG) can be combined together for surface modification of Ti-6Al-4V alloy, and when performed in a controlled atmosphere of pure nitrogen or a mixture of nitrogen and argon, can produce a wear-resistant surface alloy. Compared with laser processing, a cheaper surface modification process has been developed involving a shorter processing time, which is free of stringent requirements such as a vacuum system.展开更多
A novel scheme of fully immersing water cooling is proposed for a Nd：glass radial slab laser. The slab medium is entirely immersed in the circulating water Ailing the pumping cavity, which enables much lower temperat...A novel scheme of fully immersing water cooling is proposed for a Nd：glass radial slab laser. The slab medium is entirely immersed in the circulating water Ailing the pumping cavity, which enables much lower temperature and reasonably smaller thermal gradient in the slab medium. The radial slab is symmetrically and synchronously pumped by eight flash lamps, and produces multi-output beams with a total energy of 469md. Incoherent beam combination property of the multi-output beams is also investigated. The approach suggested here provides a way of scaling the slab lasers to much higher output levels and also a convenience for beam combinations.展开更多
By employing three reflecting volume Bragg gratings, a near-infrared 4-channel spectral-beam-combining system is demonstrated to present 720 W combined power with a combining efficiency of 94.7%. The combined laser be...By employing three reflecting volume Bragg gratings, a near-infrared 4-channel spectral-beam-combining system is demonstrated to present 720 W combined power with a combining efficiency of 94.7%. The combined laser beam is near-diffraction-limited with a beam factor M^2-1.54. During this 4-channel beam-combining process, no special active cooling measures are used to evaluate the volume Bragg gratings as combining elements are under the higher power laser operation. Thermal expansion and period distortion are verified in a 2 k W 2-channel beam-combining process, and the heat issue in the transmission case is found to be more remarkable than that in the diffraction e-se. Transmitted and diffracted beams experience wave-front aberrations with different degrees, thus leading to distinct beam deterioration.展开更多
By analyzing the traditional star-tracking correction technology,this paper studies the star-tracking direct correction method which is based on star sensor dynamic separation initial displacement angles and main erro...By analyzing the traditional star-tracking correction technology,this paper studies the star-tracking direct correction method which is based on star sensor dynamic separation initial displacement angles and main errors of inertial measure unit（IMU） in order to carry out automatic navigation and improve the hitting accuracy and quick reaction capability of near-earth flight vehicles.Through comprehensive application and improvement of the best correction factor method,this paper proposes the startracking comprehensive correction method which combines the two methods above-mentioned and the accelerometer dynamic error separation technology.The simulation results show that obvious effects can be achieved by using the star-tracking integrated correction method.展开更多
This study investigated the independent and combined effects of photodynamic therapy (PDT), laser photodynamic hyperthermia (LPDH) and 1-(4-amino-2-methyl-5-pyrimidinyl) methy1-3-(2-chloroethyl) -3-nitrosourea hydroch...This study investigated the independent and combined effects of photodynamic therapy (PDT), laser photodynamic hyperthermia (LPDH) and 1-(4-amino-2-methyl-5-pyrimidinyl) methy1-3-(2-chloroethyl) -3-nitrosourea hydrochloride (ACNU) in a rat 9L induced gliosarcoma model. The mortality rate (MR60), mean survival time (MST60), and increasing life span (ILS60) within 60 days were determined to evaluate the therapeutic effect in vivo. The MR60 and MST60 of the gliosarcoma tumor control were 100% and 16.2 days. The ILS60s of PDT and ACNU were 72.84% and 49.81%, respectively, but MR60 of both were 86.72%. All combined treatments produced significantly prolonged survival (P<0.01). The combined effects of LPDH and ACNU, MR60, MST60, and ILS60 were 60%, 43 days, and 165.4%, respectively. The ILS60 of PDT+ACNU (96.48%) and PDT+LPDH (98.58%) also indicated a synergistic or additive effect. The survival fraction and synthetic rate of DNA, RNA, and protein of glioma 9L tumor cells in vitro after single treatment of PDT or combined with antitumor drugs and laser showed that the cytotoxicity of PDT to 9L tumor cell was obvious by using Rh123, HPD, and Pf-Ⅱ as photosensitizers. Combined treatments of PDT, antitumor drugs, and laser suppressed the synthesis of DNA, RNA, and protein more significantly than single treatment with PDT.展开更多
Semiconductor diode lasers are widely used in a variety of applications, such as pumping, telecommunication, laser display, industrial manufacturing, and medical treatments because of their high wall-plug efficiency,
We proposed a novel wavelength-spread compression technique for spectral beam combining of a diode laser array. A reflector, which is parallel to the grating, is introduced to achieve a double pass with a single grati...We proposed a novel wavelength-spread compression technique for spectral beam combining of a diode laser array. A reflector, which is parallel to the grating, is introduced to achieve a double pass with a single grating.This facilitated the reduction of the wavelength spread by half and doubled the number of combined elements in the gain range of the diode laser. We achieved a power of 26.1 W under continuous wave operation using a19 element single bar with a wavelength spread of 6.3 nm, which is nearly half of the original wavelength spread of 14.2 nm, demonstrating the double-compressed spectrum capability of this structure. The spectral beam combining efficiency was 63.7%. The grating efficiency and reflector reflectance were both over 95%; hence, the efficiency loss of the double-pass grating with a reflector is acceptable. In contrast to double-grating methods,the proposed method introduces a reflector that efficiently uses the single grating and shows significant potential for a more efficient spectral beam combining of diode laser arrays.展开更多
We demonstrate a high-power blue diode laser operated at 447 nm combining laser diodes using an optical fiber bundle. As many as 127 diode lasers at 447 nm were coupled into 400 μm/0.22 NA fibers using an aspherical ...We demonstrate a high-power blue diode laser operated at 447 nm combining laser diodes using an optical fiber bundle. As many as 127 diode lasers at 447 nm were coupled into 400 μm/0.22 NA fibers using an aspherical lens group with different focus lengths. The bare fibers were mechanically bundled through high temperature ultraviolet adhesive after the coatings of the 127 fibers were stripped. The diameter of the fiber bundle was 6 mm. The total output power of such a bundle was 152 W with electro-optical conversion efficiency of 27.56%and the RMS power instability was less than ±1% within 3 h.展开更多
文摘The surface modification of materials such as Ti-6Al-4V is necessary to improve their wear resistant properties for use in tribological applications. In this paper it is shown that a laser with low power and tungsten inert gas (TIG) can be combined together for surface modification of Ti-6Al-4V alloy, and when performed in a controlled atmosphere of pure nitrogen or a mixture of nitrogen and argon, can produce a wear-resistant surface alloy. Compared with laser processing, a cheaper surface modification process has been developed involving a shorter processing time, which is free of stringent requirements such as a vacuum system.
基金Supported by the Major Innovation Program of Shandong Province under Grant No 2013CXA10006the National Natural Science Foundation of China under Grant No 61108008
文摘A novel scheme of fully immersing water cooling is proposed for a Nd：glass radial slab laser. The slab medium is entirely immersed in the circulating water Ailing the pumping cavity, which enables much lower temperature and reasonably smaller thermal gradient in the slab medium. The radial slab is symmetrically and synchronously pumped by eight flash lamps, and produces multi-output beams with a total energy of 469md. Incoherent beam combination property of the multi-output beams is also investigated. The approach suggested here provides a way of scaling the slab lasers to much higher output levels and also a convenience for beam combinations.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11474257 and 61605183
文摘By employing three reflecting volume Bragg gratings, a near-infrared 4-channel spectral-beam-combining system is demonstrated to present 720 W combined power with a combining efficiency of 94.7%. The combined laser beam is near-diffraction-limited with a beam factor M^2-1.54. During this 4-channel beam-combining process, no special active cooling measures are used to evaluate the volume Bragg gratings as combining elements are under the higher power laser operation. Thermal expansion and period distortion are verified in a 2 k W 2-channel beam-combining process, and the heat issue in the transmission case is found to be more remarkable than that in the diffraction e-se. Transmitted and diffracted beams experience wave-front aberrations with different degrees, thus leading to distinct beam deterioration.
文摘By analyzing the traditional star-tracking correction technology,this paper studies the star-tracking direct correction method which is based on star sensor dynamic separation initial displacement angles and main errors of inertial measure unit（IMU） in order to carry out automatic navigation and improve the hitting accuracy and quick reaction capability of near-earth flight vehicles.Through comprehensive application and improvement of the best correction factor method,this paper proposes the startracking comprehensive correction method which combines the two methods above-mentioned and the accelerometer dynamic error separation technology.The simulation results show that obvious effects can be achieved by using the star-tracking integrated correction method.
文摘This study investigated the independent and combined effects of photodynamic therapy (PDT), laser photodynamic hyperthermia (LPDH) and 1-(4-amino-2-methyl-5-pyrimidinyl) methy1-3-(2-chloroethyl) -3-nitrosourea hydrochloride (ACNU) in a rat 9L induced gliosarcoma model. The mortality rate (MR60), mean survival time (MST60), and increasing life span (ILS60) within 60 days were determined to evaluate the therapeutic effect in vivo. The MR60 and MST60 of the gliosarcoma tumor control were 100% and 16.2 days. The ILS60s of PDT and ACNU were 72.84% and 49.81%, respectively, but MR60 of both were 86.72%. All combined treatments produced significantly prolonged survival (P<0.01). The combined effects of LPDH and ACNU, MR60, MST60, and ILS60 were 60%, 43 days, and 165.4%, respectively. The ILS60 of PDT+ACNU (96.48%) and PDT+LPDH (98.58%) also indicated a synergistic or additive effect. The survival fraction and synthetic rate of DNA, RNA, and protein of glioma 9L tumor cells in vitro after single treatment of PDT or combined with antitumor drugs and laser showed that the cytotoxicity of PDT to 9L tumor cell was obvious by using Rh123, HPD, and Pf-Ⅱ as photosensitizers. Combined treatments of PDT, antitumor drugs, and laser suppressed the synthesis of DNA, RNA, and protein more significantly than single treatment with PDT.
基金supported by the National Natural Science Foundation of China(Nos.61404138 and 61474119)the National Basic Research Program of China(No.2013CB933303)+3 种基金the International Science Technology Cooperation Program of the Chinese Academy of Sciences(No.181722KYSB20160005)the International Science Technology Cooperation Program of China(No.2013DFR00730)the Jilin Provincial Natural Science Foundation(Nos.20160101243JC and 20150520105JH)the Opened Fund of the State Key Laboratory on Integrated Optoelectronics(No.IOSKL2016KF15)
文摘Semiconductor diode lasers are widely used in a variety of applications, such as pumping, telecommunication, laser display, industrial manufacturing, and medical treatments because of their high wall-plug efficiency,
基金the support of the Shanghai Science and Technology Committee(Nos.15JC1403500 and 16DZ2290102)the Chinese Academy of Sciences(No.QYZDJ-SSW-JSC014)
文摘We proposed a novel wavelength-spread compression technique for spectral beam combining of a diode laser array. A reflector, which is parallel to the grating, is introduced to achieve a double pass with a single grating.This facilitated the reduction of the wavelength spread by half and doubled the number of combined elements in the gain range of the diode laser. We achieved a power of 26.1 W under continuous wave operation using a19 element single bar with a wavelength spread of 6.3 nm, which is nearly half of the original wavelength spread of 14.2 nm, demonstrating the double-compressed spectrum capability of this structure. The spectral beam combining efficiency was 63.7%. The grating efficiency and reflector reflectance were both over 95%; hence, the efficiency loss of the double-pass grating with a reflector is acceptable. In contrast to double-grating methods,the proposed method introduces a reflector that efficiently uses the single grating and shows significant potential for a more efficient spectral beam combining of diode laser arrays.
基金Project supported by the Beijing Engineering Technology Research Center of All-Solid-State Lasers Advanced Manufacturing the National High Technology Research and Development Program of China(No.2014AA032607)+1 种基金the National Natural Science Foundation of China(Nos.61404135,61405186,61308032,61308033)the National Key R&D Program of China(Nos.2016YFB0401804,2016YFB0402002)
文摘We demonstrate a high-power blue diode laser operated at 447 nm combining laser diodes using an optical fiber bundle. As many as 127 diode lasers at 447 nm were coupled into 400 μm/0.22 NA fibers using an aspherical lens group with different focus lengths. The bare fibers were mechanically bundled through high temperature ultraviolet adhesive after the coatings of the 127 fibers were stripped. The diameter of the fiber bundle was 6 mm. The total output power of such a bundle was 152 W with electro-optical conversion efficiency of 27.56%and the RMS power instability was less than ±1% within 3 h.
