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1.
The C ls and 0 ls electrons in polymethyl methacrylate etched by different incident laser intensities are analysed by x-ray photoelectron spectroscopy. The results show that when the incident laser fluence increases gradually,the percentage of carbon atoms in C-C bonds decreases while the one in carbonyl group (C=O) and alkoxy group (C-O) increases, and the percentage of oxygen atoms in C=O bonds increases while the one in C-O bonds decreases. Based on the analysis of the chemical structure, the energy level transition, energy diversion, and dissociation of bonds are theoretically examined, which is consistent with the experimental results.  相似文献   
2.
聚合酶链式反应微流控芯片的准分子激光制备和应用研究   总被引:2,自引:0,他引:2  
摘要采用价格便宜的聚甲基丙烯酸甲酯(PMMA)代替价格昂贵的硅或玻璃作为聚合酶链式反应(PCR)微流控芯片的基片材料,采用柔性大且自动化程度高的准分子激光微加工方法代替加工工艺复杂的光刻化学腐蚀方法,在19 kV和18 mm/min的优化加工参数下,在48 mm×67 mm×1 mm的PMMA基片上制备出20个循环的PCR微流控芯片. 芯片微通道横截面呈梯形,底面光滑. 微通道宽104 μm,深56 μm,长2 060 mm,加工耗时约110 min. 该芯片和相同尺寸的盖片在160 N和105 ℃条件下通过热压经20 min键合在一起,键合强度为0.85 MPa. 键合后的芯片和温控系统集成在一起,采用比例积分微分(PID)方法得到的控温精度为±0.2 ℃,采用红外热像仪得到的相邻温区间的温度梯度分别为16.5和22.2 ℃,最后利用该芯片在对170 bp的DNA片段实现了体外扩增.  相似文献   
3.
CO2 laser is employed to join a piece of powder metallurgical material (PMM) to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06-0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.  相似文献   
4.
二极管激光阵列在Talbot外腔中同相模的选择   总被引:10,自引:6,他引:4       下载免费PDF全文
 从理论和实验上对二极管激光阵列在Talbot外腔中的锁相进行了研究。在同相模和异相模近场分布的基础上,利用1维情况下的菲涅耳衍射公式计算了其远场分布。根据同相模和异相模在Talbot腔中的分布特性,采用1/2 Talbot腔并将外腔镜倾斜一个角度a的方法既能选择同相模,又能使模式的功率损耗最小。二极管激光阵列芯片采用CD金刚石材料,“三明治”结构对其进行封装,明显地减小了阵列的“smile”效应。在实验中实现了二极管激光阵列同相模的锁相输出,远场单瓣模的半高全宽为0.11 mm。  相似文献   
5.
全固体小型Yb∶YAG激光器热效应及输出特性研究   总被引:3,自引:1,他引:2  
利用中红外相机及干涉测量技术研究了二极管泵浦小型Yb∶YAG激光增益介质在激光及非激光条件下的温度分布、温度梯度、热透镜效应,同时根据对热效应的研究,对激光器的参量进行了优化.研究了在不同掺杂浓度下激光器的输出特性.对于2.3at.%掺杂浓度,得到激光输出功率为1.7 W,斜效率26.2%,光-光转换效率为13.5%的实验结果;对于5.0at.% 掺杂浓度,得到激光输出功率为2.5 W,斜效率51%,光-光转换效率为24%的实验结果.  相似文献   
6.
In-phase output beam from broad-area diode array using Talbot cavity   总被引:3,自引:0,他引:3  
The robust phase locking of a linear diode array consisting of 49 broad-area emitters was demonstrated. The single lobe in the far field with output power of 0.83 W was observed. The far-field divergence was reduced to 2.0 mrad. The spectral bandwidth was reduced from 1.7 to 0.13 nm.  相似文献   
7.
In order to explore a 56-J high energy,high frequency lamp-pumped pulsed Nd:YAG solid-state laser, the main factors influencing the higher laser output energy are analyzed,the relation between output power and input power and reflectivity is simulated theoretically,and the effective measures to improve the efficiencies of the laser are brought forward.As a result,pulse width is tunable between 0.1 and 10 ms,frequency between 1 and 1000 Hz.When the input electrical power is 12 kW,the laser can output maximum single pulse energy of 56 J and average power of 500 W with the beam quality of 16.5 mm·mrad, total electro-optic efficiency of 4.2%,and the in stability of±2% output power.It is indicated that the parameters corresponds with the results of theoretical analysis and simulation.  相似文献   
8.
647W灯泵浦大功率连续Nd:YAG激光器   总被引:2,自引:0,他引:2       下载免费PDF全文
 报道了一台灯泵浦大功率连续Nd:YAG激光器。对影响大功率固体激光器模块输出功率和光束质量的主要因素进行了理论分析,并提出提高激光器效率的措施:对聚光腔的形状、结构和材料以及冷却方式,泵浦灯的参数和材料,激光晶体的参数和镀膜进行优化设计,采用径向固定的谐振腔镜。该灯泵浦YAG晶体棒总体电光转换效率为4%,光束质量为22mm·mrad,输出功率647W。  相似文献   
9.
A lamp pumped CW Nd:YAG laser is presented in this paper for the requirement of industrial application. The main factors, which affect output power and beam quality of high power solid-state laser module, are theoretically analyzed. Total electro-optics efficiency of lamp pumped Nd:YAG crystal as high as 4.0% is obtained, and output power is higher than 647 W with beam parameter product 22 mm·mrad.  相似文献   
10.
用磷酸氧钛钾 (KTP)作为倍频晶体 ,对Nd∶YAG声光调Q激光的环形腔外腔倍频技术进行了实验和理论的研究 ,利用最大平均功率 5 0W、声光调Q、输出频率 10 0 5Hz、灯抽运Nd∶YAG激光器做为基频光光源 ,在基频输入功率 35W时 ,获得了大约为 31.4 %的光光转换效率的绿光输出。从实验结果分析了环形腔倍频的特性 ,指出了该方法的优缺点。从光束质量和聚焦光斑直径方面 ,对基频光和二次谐波进行了比较 ,提供了利用CCD测得光斑的部分图片 ,分析了环形腔倍频的工作原理 ,解决了困扰倍频技术的转换效率问题和光束质量问题  相似文献   
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