共查询到19条相似文献,搜索用时 69 毫秒
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基于分子动力学方法,对石英玻璃进行了三维的纳米划痕仿真,用来研究其纳米加工性能。采用熔融-淬火的办法建立了石英玻璃的模型,并通过观察模型的截面图,分析了在制备过程中内部微观孔隙的形成过程和原因。在仿真过程中,观察了石英玻璃的变化和孔隙周围原子的运动,得到了切削力的曲线,重点研究了内部的微观空隙对划痕过程的影响。仿真结果表明:当石英玻璃冷却时,由于内部共价键的重组,会形成平均半径为0.25 nm的微观的孔隙,而且其降低了石英玻璃的纳米加工性能,使得切削力的曲线发生一定程度的波动。当磨粒划过表面后,会在表面以下形成厚度为2 nm的原子密集堆积区。由于稠密区的原子共价键键长的变化,失去了原有共价键的强度,所以会形成加工的损伤层。因此在对石英玻璃超精密加工时,应采用少量多次的加工方法来提高材料的加工性能。 相似文献
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《强激光与粒子束》2015,(2)
基于分子动力学方法,对石英玻璃进行了三维的纳米划痕仿真,用来研究其纳米加工性能。采用熔融-淬火的办法建立了石英玻璃的模型,并通过观察模型的截面图,分析了在制备过程中内部微观孔隙的形成过程和原因。在仿真过程中,观察了石英玻璃的变化和孔隙周围原子的运动,得到了切削力的曲线,重点研究了内部的微观空隙对划痕过程的影响。仿真结果表明:当石英玻璃冷却时,由于内部共价键的重组,会形成平均半径为0.25nm的微观的孔隙,而且其降低了石英玻璃的纳米加工性能,使得切削力的曲线发生一定程度的波动。当磨粒划过表面后,会在表面以下形成厚度为2nm的原子密集堆积区。由于稠密区的原子共价键键长的变化,失去了原有共价键的强度,所以会形成加工的损伤层。因此在对石英玻璃超精密加工时,应采用少量多次的加工方法来提高材料的加工性能。 相似文献
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提出低能带电粒子辐照下石英玻璃非弹性电离损伤的物理模型和速率方程,给出了电离效应产生带电离子、电子浓度的解析表达式.讨论了光密度与吸收剂量之间的变化关系,并与实验结果进行了比较.还给出光学反射镜反射率表达式及数学模拟结果.利用所建立的模型,可以定量描述低能带电粒子辐照特别是综合辐照时石英玻璃和镀金属膜反射镜光学性能随辐照剂量的变化情况.
关键词:
电离损伤
综合辐照
石英玻璃
光密度 相似文献
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利用磁控溅射方法在Si(111)衬底上制备了具有(111)和(222)择优取向的TiN薄膜. 用纳米压痕和纳米划痕方法研究了该薄膜的变形和断裂行为. 用扫描电子显微镜、纳米压痕原位原子力显微镜及原位光学显微镜并结合加-卸载 曲线及划痕曲线获得了薄膜发生变形和断裂的微观信息. 在压痕试验中, TiN薄膜在压入深度为200 nm时表现为塑性变形及压痕周围的局部断裂, 随着压入深度的增大, 塑性变形和局部断裂变得越显著, 当最大压入深度达到临界值1000 nm时, 薄膜和衬底间发生了界面断裂. 在划痕实验中, 100 mN及200 mN的最大载荷均可以引起界面断裂. 最大为200 mN的载荷使得薄膜发生界面断裂的位置比用100 mN载荷时的位置提前, 但其临界断裂载荷和100 mN时及压痕实验时的临界界面断裂载荷基本相同.
关键词:
TiN薄膜
纳米压痕
纳米划痕
界面断裂 相似文献
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光学非球曲面器件的超精密磨削加工技术研究 总被引:8,自引:1,他引:7
为磨削加工出高精度、高质量的光学非球曲面器件。详尽分析了砂轮的安装及半径等误差对零件加工精度的影响。设计研制出了一套非球曲面磨削系统 ,并用它进行了实验研究。实验结果表明 :要获得高精度的非球曲面器件 ,只有当金刚石砂轮的平均磨粒尺寸低于 10 μm ,并在采用较高的砂轮线速度和较小的进给量的情况下 ,才能实现光学非球曲面的超精密磨削加工 ,经过各种磨削参数的优化选择 ,其非球曲面最终的零件轮廓精度为 0 4 μm ,表面粗糙度Ra优于 0 0 1μm。 相似文献
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本文提出了一种在轨迹成型法加工光学零件磨床上实现脆性材料超精密磨削的微进给电控装置。试验表明,在轨迹成型法加工光学零件磨床上应用本装置对光学透镜进行磨削后,工件表面粗糙度可达Ra=0.02μm,能够达到光学零件精磨的粗糙度要求。 相似文献
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Sandugash K. Kodanova Moldir K. Issanova Tlekkabul S. Ramazanov Askar K. Khikmetov Sergey A. Maiorov 《等离子体物理论文集》2019,59(6)
In this paper, the relaxation properties of a fully ionized, hot, ideal plasma have been studied using the molecular dynamics method. As an example, the classical problem of equalization of the electron and ion temperatures for various mass ratios is considered, the relaxation times for temperatures is determined, and the influence of the number of particles and the type of boundary conditions on the simulation results is studied. The simulation results are compared with the available theoretical results. 相似文献
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《中国科学:物理学 力学 天文学(英文版)》2020,(7)
Chaos has been well understood in dynamic system, however, how the chaotic behavior occur in jerky flow in material, is still not clear, and is lack of specific chaotic attractor. Here the jerky evolution of lateral force and the stair-like fluctuation of lateral displacement are observed for Ni62 Nb38(at.%) metallic glass film during nanoscratch process. This jerky flow is investigated by using the largest Lyapunov exponent, Kolmogorov entropy and fractal dimension, and chaotic behavior of lateral force-time and normal displacement-lateral displacement sequences is verified. In addition to time series analysis, it is found that jerk equation can be used to describe the jerky flow of the metallic-glass film during nanoscratch. More importantly, unambiguous chaotic attractor is presented by jerky dynamics using "jerk"-singularities, namely the total change rate of lateral force relative to scratch time. These reveal an inner connection between jerky flow and jerky dynamics in nanoscratch of a metallic-glass film. 相似文献
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ZnO thin films with typical c-axis (0 0 2) orientation were successfully deposited on quartz glass substrates by pulse laser ablation of Zn target in oxygen atmosphere at a relatively low temperature range of 100-250 °C. The structural and optical properties of the films were studied. In photoluminescence (PL) spectra at room temperature, single ultraviolet emission (without deep-level emission) was obtained from ZnO film deposited at the temperature of 200 °C. This was attributed to its low intrinsic defects. 相似文献
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A. F. Zatsepin V. S. Kortov N. V. Gavrilov D. Yu. Biryukov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2008,2(3):450-453
The special features of optically stimulated electron emission and luminescence of defects in KV quartz glass after Cu+ ion pulse implantation are studied. It is shown that the ion-beam modification of the photoemission and luminescence properties of samples is due to the formation of radiation defects and by dimensional factors caused by the appearance of Cu nanoparticles. 相似文献
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MgxZn1-xO材料是一种新型光电功能材料.采用溶胶凝胶法在石英玻璃上制备了Mg0.25Zn0.75O薄膜,理论结合实验研究了Mg0.25Zn0.75O薄膜的结构和光学性能.研究表明,石英玻璃衬底上Mg0.25Zn0.75O薄膜呈六方纤锌矿结构,薄膜均匀,平均粒径约为20 nm.吸收光谱表明吸收带边始于360 nm,相应的禁带宽度为3.83 eV.发光光谱包含三个发射峰,分别位于384.9 nm(3.23 eV),444.8 nm(2.79 eV)和533.6 nm(2.32 eV),激发光谱峰位于378 nm.由于Mg离子的间隙缺陷导致Mg0.25Zn0.75O薄膜晶格增大,禁带宽度变宽,紫外、蓝光和绿光发射分别红移59,14和12.6 nm. 相似文献
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Plasma doping is the candidate for semiconductor doping. Accurate simulation of the doping technology is needed for the advanced integrated circuit manufacturing. In this paper, the plasma doping process simulation is performed by using the localized molecular dynamics method. Models that involve the statistics of the implanted compositions, angles and energies are developed. The effect of the model on simulation results is studied. The simulation results about the doping concentration profile are supported by experimental data. 相似文献
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El-Sayed El-Zaiat 《Optical Review》2014,21(1):54-59
In this work, an expression for the interface reflectance in terms of both the total transmittance and the total reflectance of the glass substrate is derived. Using this expression a nondestructive procedure for deducing the complex refractive index of glass bulk material is suggested. Complex refractive indices of four glassy substrates with different thicknesses and compositions are experimentally measured across a spectral range 200–2000 nm. The errors of measurements for the suggested procedure depend on the reflectance and transmittance errors. They are calculated to be of about ±2.751 × 10?8 for imaginary and ±0.008 for real refractive indices. Dispersive parameters of the real refractive indices and optical energy gaps for direct and indirect allowed optical transitions are deduced. Predicted nonlinear refractive indices and susceptibilities are evaluated. 相似文献