<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31375192</termId><termName>optical glass</termName><termType>PT</termType><termNote><![CDATA[ A highly refined glass, usually a flint glass of special composition, or made from rock crystal, used for lenses and prisms. ]]></termNote><termCreatedDate>2026-03-30 20:41:11</termCreatedDate><relation><relationType>UF</relationType><termId>31375193</termId><termName>glass, optical</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31344446</termId><termName>glass by property</termName><termType>PT</termType></relation></term>  </Zthes>