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CO_2激光深熔焊接光致等离子体控制的研究 总被引:1,自引:0,他引:1
采用2.5kWCO2激光器焊接不锈钢,设计一个由两个同轴圆管组成的双层喷嘴,研究了Ar和He的组合方式、流量、喷嘴角度等对光致等离子体控制效果的影响。当内管通Ar,外管通He且喷嘴角度大于45°时可将等离子体完全抑制在蒸发沟槽之内,从而获得具有大的熔深和深宽比的焊缝。控制等离子体所需的He气流量与焊接速度有关,焊接速度增加,He气流量减小 相似文献
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辅助气体对CO_2激光焊接光致等离子体屏蔽的影响 总被引:9,自引:2,他引:7
采用20kWCO2激光加工系统焊接低碳钢,研究了辅助气体对等离子体屏蔽临界功率密度的影响。研究结果表明,辅助气体不同时等离子体屏蔽临界功率密度由小到大的排列顺序为:Ar→N2→CO2→He。Ar作为辅助气体时,等离子体屏蔽的临界功率密度可以低至1.85×106W/cm2。辅助气体对等离子体屏蔽临界功率密度的影响主要取决于气体的导热性和解离能,相比而言,气体电离能的影响是次要的。采用Ar作为辅助气体时,等离子体屏蔽临界功率密度低的原因主要在于Ar的导热性能差,激光支持的燃烧波(Laser-supportedCombustionWaves—LSC)波容易过热和扩展。 相似文献
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本文通过脉冲染料激光514.5nm激发NaK分子,用时间分辨荧光法详细测量了D1π态有效辐射寿命随缓冲Ar气压强的变化关系,利用Stern-Vollmer曲线外推得到了在T=348℃时Nak分子D'π态(v'=1,J'=67;V'=1,J'=95:V'=3,J'=122)的自发辐射寿命分别为16.1ns,15.1ns,14.7ns。Ar气对基碰撞猝灭截面分别为2.28nm3,2.12nm2和1.95nm2。Nak分子D'π态自发辐射寿命以及Ar气对D'π态总碰撞猝灭截面的测量。 相似文献
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报道了C60掺杂气凝胶的奇异光致发光现象.利用两种掺杂方法制备了C60掺杂SiO2气凝胶样品,红外吸收光谱及飞行时间质谱测试表明C60分子被成功地掺入SiO2气凝胶中.在室温条件下,以Ar+激光(488nm,10mW)激发,观测到C60掺杂气凝胶的强可见发光,发光峰位置较纯C60明显蓝移,但不同方法制备的样品的蓝移量不同 相似文献
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研究了Cr2O3作为改性添加剂对(PbSm)(TiMn)O3系压电陶瓷介电及压电性能的影响.实验表明,添加适量的Cr2O3能得到压电性能好、压电各向异性大、压电稳定性高的优良材料,其kt=45%~50%,kt/kp=15~18,TCft3=-0.8~-6ppm/℃.因此,在研究、开发高性能压电材料过程中,Cr2O3不失为一种优良的改性材料. 相似文献
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本文在流动余辉装置上,研究了亚稳态He(2~3S)原子与N2H4分子碰撞传能,观察到了激发态产物NH(A3Π→X3∑+)、 NH(c1∏→a1△)、 NH2(A2A1→X2B1)的发射光谱,由相对光谱强度求得了形成各产物的通道比;分析 NH(A3∏,v′= 0)的转动分辨谱的结果表明,v′=0能级上的转动布居是“双模”分布, 激发态产物 NH(A)、 NH2(A)的形成机理可能是: He(2~3S+N2H4→N2H4→NH(A)+NH2(A)+H. 相似文献
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本文报道一台圆柱形结构横流CO_2激光器及其运转特性.圆筒长度1.45m,直径0.45m,已获得大于1kW的输出功率. 相似文献
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Nagai H. Hishii M. Tanaka M. Myoi Y. Wakata H. Yagi T. Tabata N. 《Quantum Electronics, IEEE Journal of》1993,29(12):2898-2909
A CW CO2 laser with power output of more than 20 kW is described. The laser consists of a discharge excitation system named SAGE (Silent-discharge Assisted Glow discharge Excitation) and a ZnSe or KCl transmissive window for extracting high-quality beams with axisymmetric intensity profile from a confocal positive-branch unstable resonator. SAGE is effective in forming a uniformly distributed and stable discharge in a large-volume, high-pressure gas excitation medium. Together with appropriate high-pressure gas conditions and a properly selected zeolite to adsorb water vapor in the laser chamber, the transmissive windows enable gas-sealed operations. The structure of the 20-kW SAGE laser and its performance characteristics are described. The maximum CW power of 26.5 kW with an efficiency of 16.5% is attained with the ZnSe window, and a 20.3-kW power output is extracted through the KCl window. Long-term gas-sealed operation at a CW power level of 20 kW has been demonstrated for a period of 65 h 相似文献
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为了解决传统双放电盒横流5kW CO2 激光器双风道、风速小、体积庞大等问题,研究开发了单放电盒横流5kW CO2 激光器,采用气体动力学、放电区气体流场分析的方法,在保证风机强度的前提下根据通风机原理设计了一款铝质轻型离心风机,风机的进口直径为382mm,出口直径为451mm,蜗壳宽度为160mm,并进行了实验验证。结果表明,配置该风机的单放电盒的5kW CO2激光器提高了功率稳定性,放电区气体平均流速从60.8m/s提高到75.5m/s,缩小了弧光放电的面积,改善了近场光斑的强度及均匀性,采用铝制风机及单放电盒减小了激光器的整体重量和体积。这对CO2激光器向高功率、小体积、紧凑型发展具有重要意义。 相似文献
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Takenaka Y. Kuzumoto M. Yasui K. Yagi S. Tagashira M. 《Quantum Electronics, IEEE Journal of》1991,27(11):2482-2487
A high-power and high-focusing continuous-wave (CW) CO2 laser with a novel unstable resonator was developed. This resonator contains a step-wise variable reflecting output coupler named the phase-unifying output coupler and a total reflector. The laser was excited by a capacitive-barriered AC discharge called a silent discharge. A linearly polarized laser beam with a diffraction-limited divergence angle of 0.55 mrad was obtained. Very stable CW laser operation at an output power of 5 kW was achieved with a threshold discharge power of 10 kW and a slope efficiency of 18% 相似文献
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《Quantum Electronics, IEEE Journal of》1988,24(3):503-506
A single-tube large-bore fast axial-flow CO2 laser with a power output of 3.8 kW using a discharge length of 0.6 m is described which operates at currents in excess of 1.2 A. The high-power compact design is made possible by the use of multiple electrodes and by optimizing gas turbulence using high-velocity gas injection at the anodes to suppress the glow-to-arc transition and to fill the discharge tube. The critical parameters in raising the current at which the glow-to-arc transition occurs are shown to be the number and surface area of the cathodes and the effectiveness of the gas turbulence over the discharge length. The importance of the transition regions between the column and the electrodes is shown. Operation at currents in excess of 2 A without a glow-to-arc transition has been achieved 相似文献
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用于白癜风治疗的308nm XeCl准分子激光系统 总被引:1,自引:0,他引:1
研制了一台用于白癜风治疗的308nm XeCl准分子激光系统。根据准分子激光器脉冲式放电的特点,设计了推挽式脉冲开关电源。实验研究了激光器脉冲重复频率、工作电压、气体寿命对激光输出能量的影响,并检测了激光输出脉冲能量的稳定性。通过自动反馈控制系统调整激光头放电工作电压实现输出激光能量的稳定。激光采用扩展型紫外液芯光纤传导,得到均匀性良好的治疗光斑,液芯光纤对308nm激光的传输效率约为70%。激光器脉冲重复频率1~200Hz,工作电压18~25kV,输出能量不稳定度小于4%。经光纤输出用于治疗的有效光斑直径22mm,脉冲能量密度2~3mJ/cm2。 相似文献
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