| 摘要 |
<p>The present application relates to techniques for detecting if an article has previously experienced certain environmental conditions, such as temperature, shock, strain, which may be adverse to the proper functioning, quality or safety, of the article. There is provided a magnetic indicator comprising a plurality of magnetic elements (1) having remotely detectable properties arranged on a substrate (2). The substrate exhibits a known response to a predetermined change in one or more environmental conditions to which the indicator may be subjected, the response being such that the remotely detectable properties of at least one of the magnetic element(s) is permanently altered.</p> |
