2q锗纳米材料制备中产量与水层的关系研究

研究激光烧蚀水面下的块体锗靶.研究结果表明,激光烧蚀锗的产量(烧蚀率)随锗基板表面水层厚度变化而变化.对单个激光脉冲为60 mJ能量时,烧蚀出的锗溶液浓度在水层为1.2 mm时最高.它揭示在水约束条件下存在一个最优水层厚度,诱导出的等离子体具有最强的冲击力,这种高压、高温等离子体导致最高的烧蚀率.对各水层厚度下烧蚀的锗颗粒粒径做了分析,得到锗纳米粒径随水层厚度增加而单调减少.XRD表明立方单晶锗经激光烧蚀后成为面心立方多晶锗,且含有亚稳相GeO.     

黏性液体在纳秒脉冲激光烧蚀下的特性研究

比较了甘油和蓖麻油在相同环境下与纳秒脉冲激光相互作用的烧蚀特性,结果发现,蓖麻油的散射斑明显大于甘油,而蓖麻油产生的压力要小于甘油,这主要是由两种液体的黏度系数、密度等物理性质的差异决定的。     

PROTOS 70卷烟机组烟支剔除装置的设计与实现

为了解决Protos 70卷烟机组在激光打孔烟支甩烟、烟支堵塞问题,采用高速电磁阀设计了一种新型的烟支剔除装置。通过高速处理模块采样烟支脉冲,计算烟支移位数,然后在搓接鼓轮安装高速剔除阀,实现高速剔除阀控制压缩空气对开机停机不合格烟支进行自动剔除。以Protos 70卷烟机组生产7000支/min为研究对象进行测试,实验结果表明,不合格烟支的剔除准确率为100%,同时激光部分故障率降低了84.62%,该装置可提高设备烟支激光打孔的稳定性。     

激光技术在汽车工业中的应用

讨论当前汽车工业中激光加工技术的应用及其发展趋势,并对激光加工技术中的激光切割、激光打孔及激光熔铸等技术进行详细的分析.     

并接两个电光偏转器的激光脉冲稳定性实验研究

介绍用两个相同的电光偏转器相应的电极并联连接后,激光脉冲光束依次通过它们进行偏转扫描的削波整形原理.由实验测出用两个电光偏转器并联比用单个对激光脉冲扫描光线更长,在同样的狭缝宽度下削出更窄的激光脉冲,提高了输出激光脉冲幅度的稳定性,幅度起伏RMS的精度提高了约33.3%,实验结果与理论基本一致.虽还没有达到理论分析预期的效果,但也说明电光偏转器偏转能力还有进一步挖掘的潜力,用电光偏转器进行激光脉冲稳定性的实验研究,在惯性约束核聚变、激光脉冲削波、整形等方面有广泛的应用前景.     

超快激光脉冲的产生和放大

超快激光脉冲是实现超高速通信最为重要的部分.近十年来,啁啾脉冲放大技术和宽带增益介质的结合,高功率超快激光脉冲取得了迅猛的发展.在小型实验室桌面激光器就可以产生数太瓦功率的激光.本文介绍了用啁啾脉冲放大技术实现超快脉冲的产生和放大.     

液体表面波对激光干涉图样的衍射调制

对于频率为几十赫兹的液体表面声波（Surface Acoustic Wave,SAW）,提出了一种激光干涉测量方法.实验上得到了表面声波不同振幅下的激光干涉图样,并对干涉条纹的强度分布情况进行了理论分析.结果表明：出现此图样以及缺级现象是由于低频液体表面波对激光干涉图样的衍射调制的结果.     

超短脉冲激光对甲醛树脂的烧蚀推进

利用波长532 nm、脉宽10 ns的短脉冲激光在不同激光能量下对甲醛树脂进行了烧蚀推进研究.通过测量激光烧蚀后的靶动量及质量损失,获得激光与甲醛树脂相互作用的动量耦合系数和比冲.     

奇特的飞秒激光

飞秒激光是激光家族中的新成员之一,它是人类在目前实验条件下所能获得的持续时间最短、以脉冲形式运转的激光.由于它具有奇特的性质,所以应用前景非常广泛.     

较高气压下激光烧蚀等离子体的动力学特性

建立一维半导体Ge的激光烧蚀模型,对波长为248nm,脉宽为17ns,峰值功率密度为4×108w/cm2的KrF脉冲激光在1000torr(1torr=133.32pa)氦气环境下烧蚀晶体Ge及产生等离子体的过程进行了数值模拟,并对计算结果进行分析比较.结果表明在惰性气体环境下,气压在1torr和1000torr之间变化对等离子体屏蔽现象的出现几乎不产生影响;背景气压的增大抑制了粒子的扩散,使等离子体的膨胀速度减小,限制了其膨胀的空间.     

深水平岩溶承压水上下组煤开采危险性评价

为评价芦岭矿Ⅱ1018工作面开采危险性,结合大量钻孔资料、抽水试验成果、底板隔水层裂隙统计和水源识别判别,分析了太灰中1灰~4灰薄层灰岩的赋存特征,评价了工作面底板隔水层阻水能力,识别了Ⅱ1018工作面上位工作面（Ⅱ1016）的出水水源。研究结果表明：1）经Fisher判别分析,Ⅱ1016工作面出水水源为灰岩水;2）1灰到4灰各单层灰岩逐渐增厚,富水性增加,但灰岩作为一整体含水层时,其富水性有随深度弱化趋势;3）10煤底到1灰隔水层厚度稳定,裂隙发育较弱,富水性差,具备有效隔水岩层的基本条件。     

Visualization of structured packing with laser induced fluorescence technique: Two-dimensional measurement of liquid concentration distribution

A method of using laser induced fluorescence(LIF)technique was applied to two-dimensional measurement of the liquid concentration distribution in the 250Y structured packing sheet. The experimental structured packing sheet was made of perspex so that the laser could pass through it. The visualization of the distribution of the liquid concentration in the structured packing sheet was realized. The calibration of the thickness and liquid concentration was carried out firstly and the regression formula I=kcd was acquired, in which concentration c and the liquid film thickness d were both considered. Then the liquid feed of uniform tracer(rhodamine)concentration entered the perspex structured packing from the top under different spraying densities. The corresponding thickness of liquid film on the packing was calculated. Finally, tracer(rhodamine)with a high concentration was injected only at one fixed point of the structured packing under different spraying densities of the liquid. With the known liquid film thickness, the concentration distribution of the tracer can be calculated inside the structured packing sheet.     

尾管悬挂器技术的应用及效益分析

在石油钻井中,尾管固井是将尾管座挂在上层管套下部的预定位置上。尾管固井可以减少套管多层重迭,节约套管;适用于深井和超深井的钻探,可以减轻钻机负荷,降低循环泵压;可采用复合钻具;简化井口,同时能降低注水时的施工压力,保证钻井施工的进行和安全性;确保尾管挺直,提高注水泥封固质量,有利于以后石油开采和修井等井下作业;综合成本分析相当可观。     

基于SLM的18Ni-300模具钢工艺参数优化

设计了以激光功率、扫描速度、扫描间距、铺粉厚度为因素的正交实验,研究了SLM 成型18Ni-300 模具钢粉末过程中各个工艺参数对成型件致密度的影响规律,并进行了工艺参数优化。实验表明,在选定范围内,成型件致密度随激光功率的增加先增大后减小?随扫描速度的增加持续减小?随扫描间距的增加先增加后减小?随铺粉厚度的增加持续减小。最优工艺参数组为激光功率260 W、扫描速度500 mm/ s、扫描间距0.11 mm、铺粉厚度0.02 mm 时,成型件致密度99.99%,为所有实验中的最优值。     

激光熔覆WC/Co多层过渡涂层与单层涂层的热应力有限元分析

在建立WC/Co多层过渡涂层与单层涂层模型的基础上,借助有限元分析软件对高温下涂层和基体的应力分布进行了模拟。在后处理阶段,对两种涂层结构分别选定了两条具有代表性的路径,同时提取两种结构对应路径上的应力,并进行了对比分析。结果表面,在界面和涂层厚度方向,多层过渡涂层的热应力总体上小于单层涂层的热应力,并且分布更加平缓。     

Upper bound analysis for estimation of the influence of seepage on tunnel face stability in layered soils

Tunnel face stability is important for safe tunneling and the protection of the surrounding environment. Upper bound analysis is a widely applied method to investigate tunnel face stability. In this paper, a tunnel face collapse of Guangzhou metro line 3 is presented. Accordingly, seepage is considered in the upper bound solutions for face stability in layered soils. Steady-state seepage is reached in the first 1200 s of each drilling step. In the crossed layer, the seepage flow is horizontal toward the tunnel face, whereas in the cover layer, the seepage vertically percolates into the crossed layer. By considering the seepage forces on the tunnel face and on the soil particles, the upper bound solution for the support pressure needed for face stability in layered soil with seepage is obtained. Under saturated conditions, the support pressure is influenced by the variation of the depth ratio due to the seepage effect. Moreover, the support pressure depends linearly on the groundwater level. This study provides estimations of the support pressure for face stability in tunnel design.     

Surface Modification of Cu-Cr Complex by NIR and MIR Laser简

Irradiated by infrared laser, the surface reducibility and adsorbability of Cu-Cr complex could be improved, owing to the interaction of photo-fragmentation and laser texturing. Analyzed by the binding energy spectra and the auger spectra, the valence states of chromium ion and copper ion were+3 and+1 after radiation respectively, which still had the reducibility to release electrons. In contrast with the near-infrared(NIR)1 064 nm and mid-infrared(MIR) 10 600 nm laser at the same average output power of 15 W, the reduced metal percentage in the Cu-Cr complex was obviously distinguished at the depth from nanometer to micron. After chemical plating, the average coating thickness and mean-square deviation of the NIR sample were 11.61 μm and 0.30 for copper layer, and 2.69 μm and 0.08 for nickel layer. The results were much better than those of the MIR sample.     

闽南沿海晚第四纪环境演变探讨

选取前湖湾的海岸剖面以及海岸、海滩两个钻孔作为代表剖面,探索闽南沿海晚第四纪环境演变的规律,对剖面、钻孔岩芯进行10cm的等间距采样．选取当地海岸的风砂、海滩、河流沉积物作为环境判别的参考,使用激光粒度仪进行粒度测试．研究表明：（1）42kaB．P以来前湖湾经历了海滩、河口河流、湖沼、海滩环境,再转为沙丘砂堆积环境的变迁;（2）古树林因42kaB．P.海面上涨被海滩沉积物所覆盖．