Brief or casual exposure to low levels of crystalline silica dust are said to not produce clinically significant lung disease.

短暂或偶然暴露水平较低的结晶矽尘表示，不会产生临床显着的肺部疾病。

The silica bricks of high refractoriness, high loading and heavy melting point made of large crystalline quartz have already increased the life to 5 times.

用大结晶脉石英制成高耐火度、高荷重软化点硅砖，使用寿命提高5倍以上。

The mineral crystalline morphology of foundry natural silica sands has been investigated, which can be divided into two groups:single crystal and polycrystalline gather.

考查了铸造用天然硅砂的矿物晶体形态， 可将其大致分为单晶体和多晶集合体两类。

For example, both crystalline and glassy forms of silica (SiO,) have structures with each si surrounded by four oxygen atoms, and each o by two si.

例如，晶体二氧化硅和石英结构的二氧化硅是每个硅原子被四个氧原子所包围，每个氧原子周围有两个硅原子。

The crystalline morphology and lattice constants of silica bricks in several status were investigated by the optic microscope, scanning electron microscope and X-ray diffraction.

利用光学显微镜、扫描电镜和X射线衍射仪研究了几种不同状态硅砖的晶体形貌和晶格常数。

Thus, the mineral crystalline morphology of natural silica sand is an important parameter for use in foundry.

考查了铸造用天然硅砂的矿物晶体形态，可将其大致分为单晶体和多晶集合体两类。

In addition, highly pozzolanic ash can be produced by means of controlled combustion, when silica is kept in non-crystalline form and cellular structure.

此外，高火山灰性(凝硬性)灰可以通过控制燃烧来产生，此时，二氧化硅保持在非结晶形式和蜂窝状结构。

The M41S, HMS, MSU, and SBA silica based crystalline mesoporous molecular sieves are of great academic and practical importance in catalysis, absorptive separation technology, and materials science.

MSU和SBA等具有规则孔道结构的介孔硅基分子筛及其杂原子衍生物在多相催化、吸附分离及材料科学领域有重要的学术研究与工程应用价值。