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Formation mechanism of a smooth, defectfree surface of fused silica optics using rapid CO2 laser polishing

International Journal of Extreme Manufacturing 2019年第3期1卷 85-95页

作者： Linjie Zhao Jian Cheng Mingjun Chen Xiaodong Yuan Wei Liao Qi Liu Hao Yang Haijun Wang State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001People’s Republic of China Research Center of Laser Fusion China Academy of Engineering PhysicsMianyang 621900People’s Republic of China

surface defects introduced by conventional mechanical processing methods can induce irreversible damage and reduce the service life of optics applied in high-power *** to mechanical processing,laser polishing with moving beam spot is a noncontact processing method,which is able to form a defect-free *** work aims to explore the mechanism of forming a smooth,defect-free fused silica surface by high-power density laser polishing with coupled multiple *** underlying mechanisms of laser polishing was revealed by numerical simulations and the theoretical results were verified by *** simulated polishing depth and machined surface morphology were in close agreement with the experimental *** obtain the optimized polishing quality,the effects of laser polishing parameters(*** rate,pulse width and polishing times)on the polishing quality were experimentally *** was found that the processing efficiency of fused silica materials by carbon dioxide(CO2)laser polishing could reach 8.68 mm2 s−1,and the surface roughness(Ra)was better than 25 ***,the cracks on pristine fused silica surfaces introduced by initial grinding process were completely removed by laser polishing to achieve a defect-free *** maximum laser polishing rate can reach 3.88μm s−1,much higher than that of the traditional mechanical polishing *** rapid CO2 laser polishing can effectively achieve smooth,defect-free surface,which is of great significance to improve the surface quality of fused silica optics applied in high-power laser facilities.

关键词： laser polishing mechanical processing smooth surface defect-free surface polishing rate

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维普期刊数据库

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LOCAL ISOMETRIC EMBEDDINGS OF surfaceS INTO A 3-SPACE

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Chinese Annals of Mathematics,Series B 1999年第2期20卷 215-222页

作者： DINGQING ZHANGYONGQIAN InstituteofMathematlcsFudanUniversity Shanghai200433China. ProjectsupportedbytheNationalNaturalScienceFoundationofChia

In the paper, the authors show that any abstract smooth surface can be locally isometricallyembedded into a class of 3-dimensional spaces Nρ0 (ρ0>0) with the non-positively sectionalcurvature being fixed sufficientl... 详细信息

关键词： Local isometric embeddings smooth surface Curvature

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维普期刊数据库

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High-quality micro-shape fabrication of monocrystalline diamond by nanosecond pulsed laser and acid cleaning

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International Journal of Extreme Manufacturing 2022年第2期4卷 173-183页

作者： Yasuhiro Okamoto Tubasa Okubo Atsuya Kajitani Akira Okada Graduate School of Natural Science and Technology Okayama UniversityOkayamaJapan

The flat plane of small surface roughness below 0.1μm average roughness was obtained for monocrystalline diamond by nanosecond pulsed laser irradiation of 1060 nm and post-process acid cleaning,at a laser fluence around the material removal threshold *** glossy and flat plane at the bottom of the micro-groove was parallel to the top surface of the specimen,although the round beam of Gaussian mode was irradiated in the direction perpendicular to the top surface of *** square beam of top-hat mode produced a shallower micro-groove with a wider,flatter bottom compared with the round beam in Gaussian *** creation method of the flat plane with small surface roughness was discussed in the arrangement strategy of linear micro-grooving by the square beam of top-hat *** side-by-side repetition of linear micro-grooving did not create a flat plane with constant ***,a two-step scanning method was proposed in order to overcome the problem in the normal side-by-side repetition of liner ***-removal areas were partly retained between the processing lines in the first step,and the laser scanning was conducted on the retained area in the second *** newly proposed two-step scanning method was practical and useful to create a widely flat plane with small surface roughness,and the two-step scanning method provided superior control over the micro-groove *** proposed method can reduce the surface roughness in addition to the shape creation of monocrystalline diamond,and it can be used as a high-quality micro-shape fabrication method of monocrystalline diamond.

关键词： monocrystalline diamond nanosecond pulsed laser flat surface smooth surface micro-grooving

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维普期刊数据库

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Influence of Cement Moulding Sands on the Structure of Castings

Influence of Cement Moulding Sands on the Structure of Casti...

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第69届世界铸造会议暨2010中国铸造活动周

作者： Ladislav Tomek Karel Rusín Ivo Stachovec Faculty of Mechanical Engineering Foundry DepartmentBrno University of TechnologyDenmark

＜正＞1 Introduction The smooth surface of castings without defects is the main demand of quality *** types of these defects,are caused by metal penetration into the sand *** of them are rough surface,burning on and burning *** defects may have significant influence of decreasing of mechanical properties,especially the fatigue *** effect can also cause poor machinability.

关键词： Molding sand Castings metal penetration smooth surface burning Fatigue life Cement EXTERNAL BURNING

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