a space that is utterly empty of all matter
真空, 虚空
完美真空的概念，即没有任何粒子或能量存在，是理论性的，用于思想实验和理论物理。
(chemistry) to merge or be merged by a chemical bond
结合, 键合
the parts or elements that something consists of and the way they are combined
组成, 成分
to heat a liquid and turn it into gas then cool it and make it liquid again in order to purify it
蒸馏, 通过蒸馏净化
精油是从各种芳香植物中蒸馏出来的。
to press two things together or be pressed together to become smaller
压缩, 压紧
工人用夹具将金属板压缩在一起。
(physics) an invisible substance that makes up most of the universe's mass, detectable only through its gravitational effects
暗物质, 黑暗物质
天文学家认为暗物质约占宇宙总质量和能量的27%。
(physics) matter consisting of elementary particles that are the antiparticles of those of regular matter
反物质, 反粒子物质
当物质和反物质粒子碰撞时，它们会相互湮灭，以伽马射线的形式释放能量。
(chemistry) a substance that causes a chemical reaction to happen at a faster rate without undergoing any chemical change itself
催化剂, 活化剂
铂纳米颗粒作为反应的催化剂，显著降低了所需的活化能。
to increase the velocity of something
加速, 提高...的速度
any water-soluble compound that can turn litmus blue and reacts with an acid to form a salt and water
碱, 碱
像碳酸钾这样的碱被用于化学实验室中中和酸。
a liquid that is capable of dissolving another substance
溶剂, 溶媒
氯仿由于其非极性性质，可作为脂类、脂肪和蜡的有效溶剂。
a sharp-smelling gas made of nitrogen and hydrogen
氨, 氨气
工业工厂大规模生产氨用于肥料。
a hard black substance consisting of an amorphous form of carbon which is made by slowly burning wood and is used as fuel or for drawing
木炭, 炭
having an electric charge
带电的, 充电的
闪电是一种自然现象，云层带电并放电。
a substance that permits electricity to pass through or along it
导体, 导电体
铝也是一种良好的导体，常用于输电线路。
a solid whose atoms, ions, or molecules are arranged in a regular repeating structure
晶体, 结晶
a particle with a net electric charge due to loss or gain of one or more electrons
离子, 带电粒子
电池通过在电极之间移动离子来产生电力。
referring to the combined interaction of electric and magnetic fields, often associated with waves or radiation
电磁的, 与电磁场有关的
电磁辐射包括无线电波、微波、红外线、可见光、紫外线、X射线和伽马射线。
the process or action of splitting a nucleus into two or more parts resulting in the release of a significant amount of energy
核裂变, 核分裂
1930年代核裂变的发现为核武器和核动力反应堆的发展铺平了道路。
(physics) the reaction in which two nuclei join together and produce energy
核聚变
太阳的能量是通过其核心中的核聚变反应产生的，主要涉及氢核聚变成氦核的过程。
to become gas or vapor from liquid
蒸发, 汽化
水坑在炎热的阳光下慢慢蒸发。
a light silver-gray metal used primarily for making cooking equipment and aircraft parts
铝, 铝
工程师们因其优异的强度重量比而更喜欢用铝来制造飞机。
a combination of two or more metals, creating a metal that is usually stronger or more resistant
合金
黄铜是铜和锌的合金，常用于管道装置和乐器中。
a reddish-brown metallic chemical element that conducts heat and electricity well and is widely used in electrical wiring and alloys
铜, 红铜
having the properties of a magnet and able to attract certain metals
磁性的, 有磁性的
the resistance or opposing force encountered when one object moves in contact with another
摩擦, 阻力
绳子在滑过金属环时经历了摩擦。
the gradual destruction of materials by chemical reaction, usually of metals
腐蚀
定期维护对于防止腐蚀和延长金属结构的使用寿命是必要的。
(physics) the property of matter that gives it weight in a gravitational field and is a measure of its inertia
质量, 物质的量
(physics) the mass of a substance or object per unit of volume
密度
the speed at which something moves in a specific direction
速度, 速率
汽车的速度可以通过行驶距离除以所用时间来计算。
a heavy soft metal, used in making bullets, in plumbing and roofing, especially in the past
铅, 重金属
(chemistry) a soft, gray-black form of carbon used as a lubricant and as a moderator in nuclear reactors
石墨, 筆鉛
a dense, silvery, toxic metal that is liquid at room temperature and can form different chemical compounds
汞, 水银
a hard, silvery, malleable, and corrosion-resistant metallic element used in alloys and plating
镍, 镍
镍通常用于不锈钢的生产。
(chemistry) a heavy, silvery-white, radioactive metal used as fuel in nuclear reactors and in nuclear weapons
铀
containing or relating to a dangerous form of energy produced by nuclear reactions
放射性的, 有放射性的
暴露于放射性材料可能会带来严重的健康风险，包括辐射病和癌症。
(physics) relating to or produced by heat
热的
