13.13 水晶系统

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  What are the different uses of lasers?
  ::激光有什么不同用途?

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  The development of modern lasers has opened many doors to both and applications. A laser beam was used to measure the distance from the Earth to the moon. Lasers are important components of CD players. As the image above illustrates, lasers can provide precise focusing of beams to selectively destroy cancer cells in patients. The ability of a laser to focus precisely is due to high-quality crystals that help give rise to the laser beam. A variety of techniques are used to manufacture pure crystals for use in lasers.
  ::现代激光技术的开发为人们打开了许多门,既打开了许多门,也打开了许多应用。激光束被用来测量地球与月球之间的距离。激光是光碟播放器的重要组成部分。如上图所示,激光可以精确地聚焦光束,有选择地摧毁病人的癌症细胞。激光的聚焦能力恰恰是由于高质量的晶体帮助产生激光束。使用多种技术制造用于激光的纯晶体。

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  Crystalline Solids
  ::晶状固体

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  The majority of solids are crystalline in nature. A crystal is a substance in which the particles are arranged in an orderly, repeating, three-dimensional pattern. Particles of a solid crystal may be , atoms, or molecules, depending on the type of substance. The three-dimensional arrangement of a solid crystal is referred to as the crystal lattice . Different arrangements of the particles within a crystal cause them to adopt several different shapes.
  ::大多数固体是自然界中的晶体。晶体是一种物质,在这种物质中,颗粒排列成有序的、重复的、三维的形态。固体晶体的粒子可以是、原子或分子,视物质类型而定。固体晶体的三维形态称为晶体板。晶体中的粒子的不同形态导致它们采用几种不同的形状。

   

   

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  Crystal Systems
  ::水晶系统

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  Crystals are classified into general categories based on their shapes. A crystal is defined by its faces, which intersect with one another at specific angles, which are characteristic of the given substance. The seven crystal systems are shown below, along with an example of each. The edge lengths of a crystal are represented by the letters $\begin{array}{r}a\end{array}$ , $\begin{array}{r}b\end{array}$ , and $\begin{array}{r}c\end{array}$ . The angles at which the faces intersect are represented by the Greek letters $\begin{array}{r}\alpha \end{array}$ , $\begin{array}{r}\beta \end{array}$ , and $\begin{array}{r}\gamma \end{array}$ . Each of the seven crystal systems differs in terms of the angles between the faces and in the number of edges of equal length on each face.
  ::晶体根据其形状分为一般类别。 晶体根据其面部定义, 脸部在特定角度相互交叉, 这是特定物质的特点。 以下显示七个晶体系统, 以及每个物质的示例。 晶体的边缘长度由字母 a、 b 和 c 表示。 面部交叉的角度由希腊字母 α、 β 和 γ 表示。 七个晶体系统中的每个系统在面部角度和每面相等长度边缘的数量上各不相同。

  Seven Basic Crystal Systems and Examples of Each

  Crystal System	Diagram	Example
  播放段落 Cubic ::立立方体 播放段落 $\begin{array}{r}a=b=c;\alpha =\beta =\gamma ={90}^{\circ }\end{array}$ ::a=b=c; @ @ @ @ @%90 @%		播放段落 Pyrite ::弹点
  播放段落 Tetragonal ::德龙 播放段落 $\begin{array}{r}a=b\ne c;\alpha =\beta =\gamma ={90}^{\circ }\end{array}$ ::a=bc;90		播放段落 Wulfenite ::伍尔芬尼特语Name
  播放段落 Orthorhombic ::矫形 播放段落 $\begin{array}{r}a\ne b\ne c;\alpha =\beta =\gamma ={90}^{\circ }\end{array}$ ::abc; 90		播放段落 Aragonite ::阿拉贡石
  播放段落 Monoclinic ::垄断诊所 播放段落 $\begin{array}{r}a\ne b\ne c;\alpha \ne {90}^{\circ }=\beta =\gamma \end{array}$ ::abc; 90		播放段落 Azurite ::阿苏特
  播放段落 Rhombohedral ::伦本加 播放段落 $\begin{array}{r}a=b=c;\alpha =\beta =\gamma \ne {90}^{\circ }\end{array}$ ::a=b=c; @ @ @ @ @%90 @%		播放段落 Calcite ::Calcite 刻度
  播放段落 Triclinic ::特里克林 播放段落 $\begin{array}{r}a\ne b\ne c;\alpha \ne \beta \ne \gamma \ne {90}^{\circ }\end{array}$ ::abc; 90		播放段落 Microcline ::微缩
  播放段落 Hexagonal ::六边形 播放段落 $\begin{array}{r}a=b\ne c;\alpha =\beta ={90}^{\circ },\gamma ={120}^{\circ }\end{array}$ ::==bc; 90 120		播放段落 Beryl ::贝丽

   

   

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  Summary
  ::摘要

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  • A crystal is a substance in which the particles are arranged in an orderly, repeating, three-dimensional pattern.
    ::晶体是一种物质,在这种物质中,粒子以有序的、重复的、三维的形态排列。
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  • The crystal lattice is the three-dimensional arrangement of a solid crystal.
    ::晶体板是固体晶体的三维结构。

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  Review
  ::回顾

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  1. What is a crystal?
     ::什么是晶体?
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  2. List the seven crystal systems.
     ::列出七个晶体系统。