File:BiodegradablePlasticUtensils2.jpg

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描述

Knives, forks, and spoons made from a biodegradable starch-polyester material. The photo has been realized using the photoelasticity method, an experimental method which gets a fairly accurate picture of stress distribution even around abrupt discontinuities in a material.


When a ray of plane polarised light is passed through a photoelastic material, it gets resolved along the two principal stress directions and each of these components experiences different refractive indices. The difference in the refractive indices leads to a relative phase retardation between the two component waves.

The setup used to photograph this photo was probably composed of:

  • A regular light source, with a quarter-wave plate installed to polarize the emerging light
  • A regular photo camera, with a quarter-wave plate installed in front of the lens

Light and camera being installed and oriented in the same direction, the two

quarter-wave plates were turned with the polarizing axis in the same direction.
日期 未知日期
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This image was released by the Agricultural Research Service, the research agency of the United States Department of Agriculture, with the ID k7245-1 (next).

This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing.

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作者 Scott Bauer
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本圖像是美國農業部人員的職務作品。作為美國聯邦政府的作品，本圖像屬於公有領域。

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当前2007年2月22日 (四) 21:192007年2月22日 (四) 21:19版本的缩略图2,548 × 1,757​（420 KB）wikimediacommons>17Drew~commonswiki{{Information |Description=Knives, forks, and spoons made from a biodegradable starch-polyester material. The photo has been realized using the photoelasticity method, an experimental method which gets a fairly accurate picture of stress distribution even

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