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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
来源
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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(二次使用本文件)
Public domain
这张图片或文件是美国农业部雇员在工作时创建的作品。作为美国联邦政府的一项作品，这个作品属于公有领域。

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See the gallery of such images, or the gallery of non-widescreen images.

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管辖区：​美国
断定方法：​美国联邦政府的作品 简体中文（已转写）

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校验和 简体中文（已转写）

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断定方法：​SHA-1 简体中文（已转写）

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1,757 像素

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2,548 像素

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当前2007年2月22日 (四) 20:192007年2月22日 (四) 20:19版本的缩略图2,548 × 1,757（420 KB）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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