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Numerical study on the performance of nozzle flow for supersonic chemical oxygen-iodine lasers 被引量:1
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作者 Zongmin Hu Junming Lā +2 位作者 Zonglin Jiang Rho-Shin Myong Tae-Hwan Cho 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2008年第2期133-142,共10页
Laser performance is greatly dependent on its operating conditions due to the strong coupling among multi- physics such as gas-dynamics, chemical reaction kinetics and optics in the mixing nozzle of COIL. In this pape... Laser performance is greatly dependent on its operating conditions due to the strong coupling among multi- physics such as gas-dynamics, chemical reaction kinetics and optics in the mixing nozzle of COIL. In this paper, 3D CFD technology is used to simulate the mixing and reactive flow of subsonic cross jet scheme at different conditions. Results obtained show that the jet penetration depth plays a dominant role in the spatial distribution of small signal gains. In the case of over-penetration, unsteady flow structures are induced by impinging between the opposing jets. The optimum spatial distribution of the chemical performance cannot be obtained even if the full penetration condition is achieved through the subsonic transverse jet mixing scheme in the COIL nozzle flow. 展开更多
关键词 chemical oxygen-iodine laser (COIL) Numerical simulation Small signal gains Unsteady structures
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Semi-gas kinetics model for performance modeling of flowing chemical oxygen-iodine lasers(COIL)
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作者 GAO Zhi HU Limin SHEN Yiqing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2004年第3期338-351,共14页
A semi-gas kinetics (SGK) model for performance analyses of flowing chemical oxygen-iodine laser (COIL) is presented. In this model, the oxygen-iodine reaction gas flow is treated as a continuous medium, and the effec... A semi-gas kinetics (SGK) model for performance analyses of flowing chemical oxygen-iodine laser (COIL) is presented. In this model, the oxygen-iodine reaction gas flow is treated as a continuous medium, and the effect of thermal motions of particles of different laser energy levels on the performances of the COIL is included and the velocity distribution function equations are solved by using the double-parameter perturbational method. For a premixed flow, effects of different chemical reaction systems, different gain saturation models and temperature, pressure, yield of excited oxygen, iodine concentration and frequency-shift on the performances of the COIL are computed, and the calculated output power agrees well with the experimental data. The results indicate that the power extraction of the SGK model considering 21 reactions is close to those when only the reversible pumping reaction is considered, while different gain saturation models and adjustable parameters greatly affect the output power, the optimal threshold gain range, and the length of power extraction. 展开更多
关键词 chemical oxygen-iodine laser (COIL) semi-gas kinetics (SGK) model rate equation (RE) model homogeneous broadening INHOMOGENEOUS broadening PERFORMANCE analysis spectral line BROADENING (SLB) model.
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Modelling the Cavity of Continuous Chemical Lasers (CCLs) Using Matlab Applications
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作者 Mohammedi Ferhat Zergui Belgacem Bensaada Said 《American Journal of Computational Mathematics》 2012年第4期331-335,共5页
The subject that concerns us in this work is the numerical simulation and optimal control of equilibrium of the continuous chemical lasers (CCLs). Laser Chemistry: Spectroscopy, Dynamics and Applications are a careful... The subject that concerns us in this work is the numerical simulation and optimal control of equilibrium of the continuous chemical lasers (CCLs). Laser Chemistry: Spectroscopy, Dynamics and Applications are a carefully structured introduction to the basic theory and concepts of this subject. In this paper we present the design and discuss the performances of a continuous DF chemical laser, based on the exothermic reaction: F+D2→DF(v,j) 展开更多
关键词 chemical laser SPECTROSCOPY VIBRATIONAL ROTATIONAL PROCESSES lasers CAVITY
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Continuous-wave operation of InAs/InP quantum dot tunable external-cavity laser grown by metal-organic chemical vapor deposition 被引量:3
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作者 Yan Wang Shuai Luo +2 位作者 Haiming Ji Di Qu Yidong Huang 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第1期568-571,共4页
We demonstrate high-performance broadband tunable external-cavity lasers(ECLs) with the metal-organic chemical vapor deposition(MOCVD) grown In As/In P quantum dots(QDs) structures. Without cavity facet coatings, the ... We demonstrate high-performance broadband tunable external-cavity lasers(ECLs) with the metal-organic chemical vapor deposition(MOCVD) grown In As/In P quantum dots(QDs) structures. Without cavity facet coatings, the 3-d B spectral bandwidth of the Fabry–Perot(FP) laser is approximately 10.8 nm, while the tuning bandwidth of ECLs is 45 nm.Combined with the anti-reflection(AR)/high-reflection(HR) facet coating, a 92 nm bandwidth tuning range has been obtained with the wavelength covering from 1414 nm to 1506 nm. In most of the tuning range, the threshold current density is lower than 1.5 k A/cm2. The maximum output power of 6.5 m W was achieved under a 500 m A injection current.All achievements mentioned above were obtained under continuous-wave(CW) mode at room temperature(RT). 展开更多
关键词 InAs/InP quantum dot external-cavity laser continuous-wave operation metal-organic chemical vapor deposition
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Quantum cascade lasers grown by MOCVD
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作者 Yongqiang Sun Guangzhou Cui +10 位作者 Kai Guo Jinchuan Zhang Ning Zhuo Lijun Wang Shuman Liu Zhiwei Jia Teng Fei Kun Li Junqi Liu Fengqi Liu Shenqiang Zhai 《Journal of Semiconductors》 EI CAS CSCD 2023年第12期47-63,共17页
Sharing the advantages of high optical power,high efficiency and design flexibility in a compact size,quantum cascade lasers(QCLs)are excellent mid-to-far infrared laser sources for gas sensing,infrared spectroscopic,... Sharing the advantages of high optical power,high efficiency and design flexibility in a compact size,quantum cascade lasers(QCLs)are excellent mid-to-far infrared laser sources for gas sensing,infrared spectroscopic,medical diagnosis,and defense applications.Metalorganic chemical vapor deposition(MOCVD)is an important technology for growing high quality semiconductor materials,and has achieved great success in the semiconductor industry due to its advantages of high efficiency,short maintenance cycles,and high stability and repeatability.The utilization of MOCVD for the growth of QCL materials holds a significant meaning for promoting the large batch production and industrial application of QCL devices.This review summarizes the recent progress of QCLs grown by MOCVD.Material quality and the structure design together determine the device performance.Research progress on the performance improvement of MOCVD-grown QCLs based on the optimization of material quality and active region structure are mainly reviewed. 展开更多
关键词 quantum cascade lasers continuous wave high optical power metal organic chemical vapor deposition broad gain
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Fabrication of Through Micro-hole Arrays in Silicon Using Femtosecond Laser Irradiation and Selective Chemical Etching 被引量:2
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作者 高博 陈涛 +2 位作者 陈颖 司金海 侯洵 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第10期142-145,共4页
We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the c... We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated. 展开更多
关键词 Fabrication of Through Micro-hole Arrays in Silicon Using Femtosecond laser Irradiation and Selective chemical Etching Figure
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Development of Electrospray Laser Chemical Vapour Deposition for Homogenous Alumina Coatings 被引量:1
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作者 Teiichi KIMURA 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第1期11-14,共4页
Electrospray,as a liquid source supply system,has been applied to chemical vapour deposition(CVD).In thermal CVD,the microstructure of the obtained films changes from dense to coarse granular because of the decreasi... Electrospray,as a liquid source supply system,has been applied to chemical vapour deposition(CVD).In thermal CVD,the microstructure of the obtained films changes from dense to coarse granular because of the decreasing surface temperature during deposition.Using the electrospray laser chemical vapour deposition method,we prepared homogenous alumina coatings.We found that laser irradiation was effective in compensating the surface temperature decrease,and an alpha-alumina coating with dense columnar microstructures was obtained at a deposition rate of 200 μm/h using 200 W Nd:YAG laser irradiation. 展开更多
关键词 electrospray laser chemical vapour deposition homogenous Alumina coating
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Effect of hydrogen fluoride and magnesium oxide on AZ31 Mg alloy/carbon fiber-reinforced plastic composite by thermal laser joining technique
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作者 Andrews Nsiah Ashong Barton Mensah Arkhurst +2 位作者 Youn Seoung Lee Mok-Young Lee Jeoung Han Kim 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第7期2874-2889,共16页
Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRP... Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRPs)through laser-assisted metal and plastic direct joining(LAMP).This study uses the LAMP technique to produce AZ31-CFRP joints.The joining process involves as-received AZ31,HFpretreated AZ31,and thermally oxidized HF-pretreated AZ31 alloy sheets.Furthermore,the bonding strength of joints prepared with thermally oxidized AZ31 alloy sheets is examined to ascertain the combined effect of HF treatment and thermal oxidation on bonding strength.The microstructures,surface chemical interactions,and mechanical performances of joints are investigated under tensile shear loading.Various factors,such as bubble formation,CFRP resin decomposition,and mechanical interlocking considerably affect joint strength.Additionally,surface chemical interactions between the active species on metal parts and the polar amide along with carbonyl groups of polymer play a significant role in improving joint strength.Joints prepared with surface-pretreated AZ31 alloy sheets show significant improvements in bonding strength. 展开更多
关键词 Thermal laser joining Thermal oxidation Hydrofluoric acid pretreatment Mechanical interlocking Covalent bonds chemical interactions
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Laser-induced voltage effects in Ca_3Co_4O_9 thin films on tilted LaAlO_3(001) substrates grown by chemical solution deposition 被引量:1
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作者 王淑芳 陈明敬 +5 位作者 赵书瑞 陈景春 何立平 于威 王江龙 傅广生 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期441-444,共4页
Laser-induced voltage effects in c-axis oriented Ca3Co4O9 thin films have been studied with samples fabricated on 10°tilted LaAIO3 (001) substrates by a simple chemical solution deposition method. An open-circu... Laser-induced voltage effects in c-axis oriented Ca3Co4O9 thin films have been studied with samples fabricated on 10°tilted LaAIO3 (001) substrates by a simple chemical solution deposition method. An open-circuit voltage with a rise time of about 10 ns and full width at half maximum of about 28 ns is detected when the film surface is irradiated by a 308-nm laser pulse with a duration of 25 ns. Besides, opemcircuit voltage signals are also observed when the film surface is irradiated separately by the laser pulses of 532 nm and 1064 nm. The results indicate that Ca3Co4O9 thin films have a great potential application in the wide range photodetctor from the ultraviolet to near infrared regions. 展开更多
关键词 laser-induced voltage Ca3Co4O9 thin films chemical solution deposition
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Influence of Laser-Induced Bubble Formation on Laser Chemical Machining
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作者 Marcel Simons Tim Radel +1 位作者 Raj Shanta Kajsaravally Frank Vollertsen 《Journal of Surface Engineered Materials and Advanced Technology》 2020年第2期21-33,共13页
Laser Chemical Machining (LCM) is a non-conventional processing method, which enables very accurate and precise ablation of metallic surfaces. Material ablation results from laser-induced thermal activation of heterog... Laser Chemical Machining (LCM) is a non-conventional processing method, which enables very accurate and precise ablation of metallic surfaces. Material ablation results from laser-induced thermal activation of heterogeneous chemical reactions between electrolytes and a metallic surface. However, when processing metallic surfaces with LCM, large fluctuations in ablation quality can occur due to rising bubbles. The for-mation of bubbles during laser chemical machining and their influence on the ablation quality has not been investigated. For a more detailed investigation of the bubbles, ablation experiments on Titanium and Ce-ramic under different thermal process conditions were performed. The experiments were recorded by a high-speed camera. The evaluation of the video sequences was performed using Matlab. The resulting bubbles were analyzed regarding their size and frequency. The results show that boil-ing bubbles formed on both materials during processing. Titanium also produces smaller bubbles, which can be identified as process bubbles ac-cording to their size. Furthermore, it was found that undisturbed laser chemical ablation can be achieved in the presence of a boiling process, since both boiling bubbles and process bubbles were detected during machining within the process window. 展开更多
关键词 MICRO MACHINING laser MICRO MACHINING laser chemical Removal Nucleate BOILING Highspeed Videography
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Thermal Analysis of Laser Chemical Machining: Part I: Static Irradiation
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作者 Hamza Messaoudi Sandro Eckert Frank Vollertsen 《Materials Sciences and Applications》 2017年第10期685-707,共23页
The laser chemical machining is a non-conventional substractive processing method. It is based on the laser-activation of a material dissolution of metals in electrolyte ambient via local-induced temperature gradients... The laser chemical machining is a non-conventional substractive processing method. It is based on the laser-activation of a material dissolution of metals in electrolyte ambient via local-induced temperature gradients and allows a gentle and smooth processing of especially temperature-sensitive metals. However, the material removal is characterized by a narrow process window and is restricted by occurring disturbances, which are supposed to be related to the localized electrolyte boiling. In order to control the removal quality and avoid disturbances, the correlation between the laser-induced temperatures and the resulting removal geometry has to be better understood. In this work an analytical modeling of the laser-induced temperatures at the surface of titanium based on a Green-function approach is presented. The main influencing factors (laser, electrolyte, material) as well as possible heat transfer into the electrolyte are included and discussed. To verify the calculated temperatures, single spot experiments are performed and characterized for titanium in phosphoric acid solution within laser irradiation of 1 s. The correlation between the temperature distribution and the resulting removal geometry is investigated based on a spatial superposition. Thereby, the bottom limit temperature is found to range between 63°C and 70°C whereas the upper limit is related to the nucleate boiling regime. Based on the performed correlation an indicator is identified to predict the ruling removal regime and thereby to reduce the experimental expenditure. 展开更多
关键词 laser Micro MACHINING laser chemical Removal Modeling Temperature Process Stability TITANIUM
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Process Window Expansion of Laser Chemical Machining by Using High Pressure
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作者 Marcel Simons Tim Radel Frank Vollertsen 《Materials Sciences and Applications》 2020年第5期296-304,共9页
Laser Chemical Machining (LCM) is a non-conventional removal process, based on a precise thermal activation of heterogeneous chemical reactions between an electrolyte and a metallic surface. Due to local overheating d... Laser Chemical Machining (LCM) is a non-conventional removal process, based on a precise thermal activation of heterogeneous chemical reactions between an electrolyte and a metallic surface. Due to local overheating during the process, boiling bubbles occur, which can impair the removal quality. In order to reduce the amount of bubbles, the laser chemical process is performed at different process pressures. Removal experiments were performed on Titanium Grade 1 using the electrolyte phosphoric acid at various process pressures, machining speeds and laser powers in order to determine the limit of the process window by evaluating the characteristics of the removal cavities. As a result, the process window for non-disturbed laser chemical machining is widened at higher process pressures. The process pressures have no influence on the geometric shape of the removal. The expansion of the process window is attributed to the fact that at higher process pressures the saturation temperature of the electrolyte rises, so that bubble boiling starts at a higher surface temperature on the workpiece induced by the laser power. The removal rate could be increased by a factor of 2.48 by increasing the process pressures from ambient pressure to 6 bar, thus taking an important step towards the economic efficiency of the laser chemical machining. 展开更多
关键词 MICRO MACHINING laser MICRO MACHINING laser chemical REMOVAL REMOVAL Rate Process Pressure
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Chemical Selectivity of Laser Ion Source for on-Line Mass Separator
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作者 Zhao, Zhizheng Yang, Yongfeng +1 位作者 Cai, Xicheng Somerville, L.P. 《Chinese journal of nuclear physics》 EI 1997年第1期48-52,共5页
Thulium(Tm)atoms are resonantly ionized in a hot tube by stepwise excitations us-ing three dye lasers pumped by a series of copper vapor pulsed at a 10 kHz rate.The chemicalselectivity of the laser ion source is measu... Thulium(Tm)atoms are resonantly ionized in a hot tube by stepwise excitations us-ing three dye lasers pumped by a series of copper vapor pulsed at a 10 kHz rate.The chemicalselectivity of the laser ion source is measured as a function of temperature of the tubes made ofTa,Nb-Zr and TaC.The chemical selectivity rises from 50 to 10000 with decreasing tube temp-erature and strongly depends on the tube material.A chemical selectivity of about 10000 withhigh efficiencies is obtained with the Nb-Zr and TaC tubes.Such a laser ion source can be usedin on-line mass separator to obtain isobarically pure ion beams. 展开更多
关键词 laser ION SOURCE chemical SELECTIVITY ON-LINE MASS SEPARATOR
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An efficient light-to-heat conversion coupling photothermal effect and exothermic chemical reaction in Au NRs/V_(2)C MXene membranes for high-performance laser ignition
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作者 Bo Yang Peng-fei Tang +6 位作者 Chun-jiao Liu Rui Li Xiao-dong Li Jin Chen Zhi-qiang Qiao Hong-ping Zhang Guang-cheng Yang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第5期834-842,共9页
MXene,a new type of two-dimensional materials,have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years... MXene,a new type of two-dimensional materials,have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years.Herein,we report the intriguing light-to-heat conversion property of vanadium carbide(V_(2)C)MXene under irradiation of millisecond laser pulse.Unlike the typical photothermal materials,the V_(2)C MXene not only converts the incident laser energy to heat by the physical photothermal effect,but also triggers the exothermic oxidation of the V_(2)C MXene.The oxidation could be greatly promoted with addition of plasmonic Au nanorods(Au NRs)for light absorption enhancement.Owing to the unique light-to-heat conversion property,the Au NRs/V_(2)C MXene membrane could serve as high temperature pulse(HTP)generators that is proposed for numerous applications with high demand for immediacy.As a proof-of concept application,Au NRs/V_(2)C MXene membrane was applied for laser ignition of the high energy density materials,such as 2,4,6,8,10,12-(hexanitrohexaaza)cyclododecane(HNIW or CL-20).An improved ignition performance,in terms of lowered laser threshold,is achieved as compared to the state-of-the-art light-to-heat conversion materials. 展开更多
关键词 V_(2)C MXene Light-to-heat conversion Exothermic chemical reaction Plasmonic Au nanorods High temperature pulse laser ignition
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Fabrication of micro carbon pillar by laser-induced chemical vapor deposition
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作者 周健 罗迎社 +3 位作者 李立君 钟琦文 李新华 殷水平 《Journal of Central South University》 SCIE EI CAS 2008年第S1期197-201,共5页
Argon ion laser was used as the induced light source and ethane(C2H4) was selected as the precursor gas,in the variety ranges of laser power from 0.5 W to 4.5 W and the pressure of the precursor gas from 225×133.... Argon ion laser was used as the induced light source and ethane(C2H4) was selected as the precursor gas,in the variety ranges of laser power from 0.5 W to 4.5 W and the pressure of the precursor gas from 225×133.3 Pa to 680×133.3 Pa,the experiments of laser induced chemical vapor deposition were proceeded for fabrication of micro carbon pillar.In the experiments,the influences of power of laser and pressure of work gas on the diameter and length of micro carbon pillar were investigated,the variety on averaged growth rate of carbon pillar with the laser irradiation time and moving speed of focus was discussed.Based on experiment data,the micro carbon pillar with an aspect ratio of over 500 was built through the method of moving the focus. 展开更多
关键词 laser-INDUCED chemical vapor deposition(LCVD) GROWING rapid DIAMETER microcarbon.
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Photoluminescence and lasing properties of InAs/GaAs quantum dots grown by metal-organic chemical vapour deposition
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作者 梁松 朱洪亮 +7 位作者 潘教青 赵玲娟 王鲁峰 周帆 舒惠云 边静 安欣 王圩 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第11期4300-4304,共5页
Photoluminescence (PL) and lasing properties of InAs/GaAs quantum dots (QDs) with different growth procedures prepared by metalorganic chemical vapour deposition are studied. PL measurements show that the low grow... Photoluminescence (PL) and lasing properties of InAs/GaAs quantum dots (QDs) with different growth procedures prepared by metalorganic chemical vapour deposition are studied. PL measurements show that the low growth rate QD sample has a larger PL intensity and a narrower PL line width than the high growth rate sample. During rapid thermal annealing, however, the low growth rate sample shows a greater blueshift of PL peak wavelength. This is caused by the larger InAs layer thickness which results from the larger 2-3 dimensional transition critical layer thickness for the QDs in the low-growth-rate sample. A growth technique including growth interruption and in-situ annealing, named indium flush method, is used during the growth of GaAs cap layer, which can flatten the GaAs surface effectively. Though the method results in a blueshift of PL peak wavelength and a broadening of PL line width, it is essential for the fabrication of room temperature working QD lasers. 展开更多
关键词 metal-organic chemical vapour deposition InAs/GaAs quantum dots laser
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DIRECT REVASCULARIZATION OF THE ISCHEMIC MYOCARDIUM USING Nd:YAG LASER
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作者 Gang Wang Weiyong Liu Zhon ghua Wang Yulin Liao Youchi Guo Hongmei Tan Nan Yi Department of Thoracic and Cardiovascular Surgery,Xijing Hospital,Xi’an 710032,Shanxi,China 《Chinese Journal of Biomedical Engineering(English Edition)》 1993年第4期146-147,共2页
For the establishment of direct revascularication of the ischemic myocardium,aNd: YAG laser with a wavelength of 1060 nm and an opitic fiber diameter of 500 umwas used to create 20 to 25 transmural channels in the cen... For the establishment of direct revascularication of the ischemic myocardium,aNd: YAG laser with a wavelength of 1060 nm and an opitic fiber diameter of 500 umwas used to create 20 to 25 transmural channels in the central ischemic region of theleft ventricle after the coronary was ligatured.The channels were created from theepicard1al surface to the endocardium and each channel received about 64 joules of 展开更多
关键词 laser created MYOCARDIUM VENTRICLE branch DESCENDING NUMBER chemic finding DEGENERATION
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废钢检验的现状分析与展望
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作者 马飞跃 《河北冶金》 2024年第3期1-5,39,共6页
在双碳背景下,废钢的综合利用尤为重要。而废钢质量的好坏和成本高低则直接影响了企业的生产效率和经济效益,故国家标准《GB/T 39733-2020再生钢铁原料》对废钢的质量检验提出了更高的要求。本文从放射性污染物、爆炸性物品、危险废物... 在双碳背景下,废钢的综合利用尤为重要。而废钢质量的好坏和成本高低则直接影响了企业的生产效率和经济效益,故国家标准《GB/T 39733-2020再生钢铁原料》对废钢的质量检验提出了更高的要求。本文从放射性污染物、爆炸性物品、危险废物、夹杂物、化学成分、锈蚀和镀层方面分析了废钢检验的现状,并对废钢检验技术的发展进行了展望。指出,利用通道式放射性检测装置对进厂废钢进行初检非常有必要;危险废物鉴别标准与技术规范有待完善,鉴别程序可操作性不强;利用激光诱导击穿光谱法可对废钢成分进行快速测量,相关决定系数和均方根误差较满意;基于颜色特征和纹理特征的废钢锈层识别算法,可准确识别训练集和预测集的废钢锈层。加强废钢检验标准体系建设、加大按化学成分对废钢进行精细分类的研发力度,尤其是基于激光诱导击穿光谱技术对废钢成分进行在线、快速、准确、定量分析是其未来的发展方向。 展开更多
关键词 废钢 检验 化学成分 激光诱导击穿光谱 镀层
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Microstructure of TA2/TA15 graded structural material by laser additive manufacturing process 被引量:29
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作者 钱婷婷 刘栋 +2 位作者 田象军 刘长猛 王华明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第9期2729-2736,共8页
TA2/TA15 graded structural material(GSM) was fabricated by the laser additive manufacturing(LAM) process. The chemical composition, microstructure and micro-hardness of the as-deposited GSM were investigated. The ... TA2/TA15 graded structural material(GSM) was fabricated by the laser additive manufacturing(LAM) process. The chemical composition, microstructure and micro-hardness of the as-deposited GSM were investigated. The results show that the TA2 part of exhibiting near-equiaxed grains was Widmanst?tten α-laths microstructure. The TA15 part containing large columnar grains was fine basket-weave microstructure. The graded zone was divided into four deposited layers with 3000 μm in thickness. As the distance from the TA2 part increases, the alloy element contents and the β phase volume fraction increase, the α phase volume fraction decreases and the microstructure shows the evolution from Widmanst?tten α-laths to basket-weave α-laths gradually. The micro-hardness increases from the TA2 part to the TA15 part due to the solid solution strengthening and grain boundary strengthening. 展开更多
关键词 laser additive manufacturing TA2/ TA15 graded structural material MICROSTRUCTURE chemical composition
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Phase retarder in chemical oxygen-iodine laser at 45° incidence
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作者 王方 黄建兵 +1 位作者 王英剑 范正修 《Chinese Optics Letters》 SCIE EI CAS CSCD 2006年第2期114-115,共2页
A phase retarder used in chemical oxygen-iodine laser (COIL) system has been fabricated by ion beam sputtering (IBS). When the incident angle is 45°the reflectivity is about 99.9% from 1290 to 1340 nm and abo... A phase retarder used in chemical oxygen-iodine laser (COIL) system has been fabricated by ion beam sputtering (IBS). When the incident angle is 45°the reflectivity is about 99.9% from 1290 to 1340 nm and about 83.8% at 632.8 nm, and the phase retardance between the parallel and perpendicular polarization components is -92.8°at 1315 nm. In order to get the influence of temperature on the phase retarder, six samples have been annealed from 523 to 648 K at interval of 25 K in air respectively, and the results show good temperature performance, With increasing temperature phase retardance becomes smaller, and the variation is within 4° at 1315 nm. At the same time, the variation maintains within ±10° for the incidence from 44°to 49°. 展开更多
关键词 ANNEALING chemical lasers IODINE Ion beams Oxygen Polarization Reflection SPUTTERING Temperature
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