According to Kirchhoff's scalar diffraction theory, with the ray tracing method, a continuous relief mask for diffractive focus lens has been designed.

基于基尔霍夫标量衍射理论，采用光线追迹法设计了连续型平面衍射聚光透镜掩模。

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Usually go out wearing a mask, a small crowd to focus on public places, avoid contact with the patient.

平时外出戴口罩，少去人群集中的公共场所，避免接触病人。

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As the artist has moved beyond the Mask painting, his focus has shifted to man's relationship to a landscape imbued with dark and inexplicable moods.

他在完成《面具》系列绘画作品后把注意力转移到了人类与情境的关系上，这些情境往往渗透著黑暗与费解的情绪。

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In another example, concert-goers could use the hearing mask to focus on a certain performer at a concert.

CNN: This mask gives you superhuman abilities