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Earth & Geophysics地质学地质学（英语：geology）是对地球的起源、历史与结构进行研究的学科。主要研究地球的物质组成、内部构造、外部特征、各圈层间的相互作用和演变历史。在现阶段，由于观察、研究条件的限制，主要以岩石圈为研究对象，并涉及水圈、大气圈、生物圈和岩石圈下更深的部分，以及涉及其他行星和卫星的太空地质学。
Geology is a branch of natural science concerned with the Earth and other astronomical bodies, the rocks of which they are composed, and the processes by which they change over time. The name comes from Ancient Greek γῆ (gê) 'earth' and λoγία (-logía) 'study of, discourse'. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 赤经（英文Right ascension；缩写为RA；符号为α）是天文学使用在天球赤道坐标系统内的坐标值之一，通过天球两极并与天赤道垂直，另一个坐标值是赤纬。
In astronomy, right ascension (abbreviated RA; symbol α) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the Earth. When paired with declination, these astronomical coordinates specify the location of a point on the celestial sphere in the equatorial coordinate system. An old term, right ascension (Latin: ascensio recta) refers to the ascension, or the point on the celestial equator that rises with any celestial object as seen from Earth's equator, where the celestial equator intersects the horizon at a right angle. It contrasts with oblique ascension, the point on the celestial equator that rises with any celestial object as seen from a given latitude on Earth, where the celestial equator intersects the horizon at an oblique angle.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 在固体力学中，剪切模量或刚性模量，用 G（有时用 S 或 μ）表示，是材料弹性剪切刚度的量度，定义为剪切应力与剪切应变之比： G := τ x y γ x y = F A Δ x l...
In solid mechanics, the shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is a measure of the elastic shear stiffness of a material and is defined as the ratio of shear stress to shear strain: G := τ x y γ x y = F A Δ x l...
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 合金，就是两种或两种以上化学物质（至少有一组分为金属）混合而成具有金属特性的物质，一般由各组分熔合成均匀的液体，再经冷凝而得。 合金至少是以下三种中的一种：元素形成的单一相固态溶液，许多金属相形成的混合物，金属形成的金属互化物。固态溶液的合金其微观结构有单一相，部分为溶液的合金则是有二相或二相以上，其分布可能是均匀，也可能不均匀，依材料冷却过程的温度变化而定。金属互化物一般会有一种合金或纯金属包在另一种纯金属内。 由于合金一些特性比纯金属元素要好，因此会用在特定的应用中。合金的例子包括钢、焊料、黄铜、白镴、磷青铜及汞齐等。 合金的成分一般是以质量比例来计算。合金依其原子组成的方式，可以区分为替代合金或间质合金，又可以进一步区分为匀相（只有一相）、非匀相（不止一相）及金属互化物（两相之间没有明显的边界）。
An alloy is a mixture of chemical elements of which in most cases at least one is a metallic element, although the word is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have properties that differ from those of the pure elements from which they are made. The vast majority of metals used for commercial purposes are alloyed to improve their properties or behavior, such as increased strength, hardness or corrosion resistance. Metals may also be alloyed to reduce their overall cost, for instance alloys of gold and copper. In an alloy, the atoms are joined by metallic bonding rather than by covalent bonds typically found in chemical compounds. The alloy constituents are usually measured by mass percentage for practical applications, and in atomic fraction for basic science studies. Alloys are usually classified as substitutional or interstitial alloys, depending on the atomic arrangement that forms the alloy.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 在化学、生物化学及药理学中，解离常数（英语：dissociation constant， K d {\displaystyle K_{d}} ）是一种特定类型的平衡常数，用于衡量一较大物体与另一较小组分分开（解离）的倾向，也可以描述配合物解体成组分分子或盐分裂为其组分离子。解离常数是缔合常数的倒数。对于一些特定的盐，解离常数亦可被称为电离常数。
In chemistry, biochemistry, and pharmacology, a dissociation constant (KD) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions. The dissociation constant is the inverse of the association constant. In the special case of salts, the dissociation constant can also be called an ionization constant.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 仿真（英语：simulation）或译作模拟，泛指基于实验或训练为目的，将原本的真实或抽象的选定系统或流程，建立一个模型以表征其关键特性（key characteristics）或者行为、功能，予以系统化与公式化，以便进行可对关键特征做出仿真。模型表示系统自身，而仿真表示系统的时序行为。 电脑仿真常被用来研究仿真模型（simulation model）。仿真也被用于对自然系统或人造系统的科学建模以获取深入理解。仿真可以用来展示可选条件或动作过程的最终结果。仿真也会用在因为无法接近、也可能太过于危险或不可接受的后果、或者设计了但还未建造、或者根本就不存在等原因而不能在真实的系统中达成的。仿真的关键是获取相关选定的关键特性与行为的有效信息源，仿真时使用简化的近似或者假定，仿真结果的保真度（fidelity）与有效性。模型验证（verification）与有效性（validation）的过程、协议是学术学习、改进、研究、开发仿真技术的热点，特别是对计算机仿真。 仿真保真度（Simulation Fidelity）用于描述仿真精度，模拟真实对应物有多近似： 低保真：对系统的最小模拟，接受输入产生输出 中等保真：对刺激能自动响应，有限精度 高保真：接近不可辨识或者尽可能地接近真实系统
A simulation is an imitative representation of a process or system that could exist in the real world. In this broad sense, simulation can often be used interchangeably with model. Sometimes a clear distinction between the two terms is made, in which simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Another way to distinguish between the terms is to define simulation as experimentation with the help of a model. This definition includes time-independent simulations. Often, computers are used to execute the simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 仿真（英语：simulation）或译作模拟，泛指基于实验或训练为目的，将原本的真实或抽象的选定系统或流程，建立一个模型以表征其关键特性（key characteristics）或者行为、功能，予以系统化与公式化，以便进行可对关键特征做出仿真。模型表示系统自身，而仿真表示系统的时序行为。 电脑仿真常被用来研究仿真模型（simulation model）。仿真也被用于对自然系统或人造系统的科学建模以获取深入理解。仿真可以用来展示可选条件或动作过程的最终结果。仿真也会用在因为无法接近、也可能太过于危险或不可接受的后果、或者设计了但还未建造、或者根本就不存在等原因而不能在真实的系统中达成的。仿真的关键是获取相关选定的关键特性与行为的有效信息源，仿真时使用简化的近似或者假定，仿真结果的保真度（fidelity）与有效性。模型验证（verification）与有效性（validation）的过程、协议是学术学习、改进、研究、开发仿真技术的热点，特别是对计算机仿真。 仿真保真度（Simulation Fidelity）用于描述仿真精度，模拟真实对应物有多近似： 低保真：对系统的最小模拟，接受输入产生输出 中等保真：对刺激能自动响应，有限精度 高保真：接近不可辨识或者尽可能地接近真实系统
A simulation is an imitative representation of a process or system that could exist in the real world. In this broad sense, simulation can often be used interchangeably with model. Sometimes a clear distinction between the two terms is made, in which simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Another way to distinguish between the terms is to define simulation as experimentation with the help of a model. This definition includes time-independent simulations. Often, computers are used to execute the simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 巴氏消毒法（英语：pasteurisation / pasteurization），又称“低温杀菌法”，是一种食物保存方法，由法国生物学家路易·巴斯德于1864年发明。原理是用低于100摄氏度（°C）的短暂加热，进行消毒，以杀死液体中的微生物，使食物在不变质的状况下延长保存时间。确切温度和时间依照液体的种类和它所含的微生物的性质而不同，一般介于70—90 °C（158—194 °F）之间。现在主要用于牛奶、葡萄酒、啤酒、果汁等发酵产品。
In food processing, pasteurization (-isation) is a process of food preservation in which packaged foods (e.g., milk and fruit juices) are treated with mild heat, usually to less than 100 °C (212 °F), to eliminate pathogens and extend shelf life. Pasteurization either destroys or deactivates microorganisms and enzymes that contribute to food spoilage or the risk of disease, including vegetative bacteria, but most bacterial spores survive the process. Pasteurization is named after French microbiologist Louis Pasteur, whose research in the 1860s demonstrated that thermal processing would deactivate unwanted microorganisms in wine. Spoilage enzymes are also inactivated during pasteurization. Today, pasteurization is used widely in the dairy industry and other food processing industries for food preservation and food safety.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 环境化学是研究化学物质在环境中迁移、转化、降解规律，研究化学物质在环境中的作用的学科。它不应与绿色化学，即探求如何减少潜在的污染源头的学科搞混。它可以定义为研究源头、反应、物质运动、作用效果、以及化学元素在空气、土壤和水利环境的生存和人类活动对其的影响。 环境化学是在各个学科之间的科学，包括大气、水生以及土壤化学，也减轻在分析化学和使环境与其他有关科学的部分发生关系起到很大作用。 环境化学重要的研究成果是发现DDT在环境中很难降解，并会在通过食物链在动物体内蓄积，导致在全世界禁止生产、使用DDT；另外发现氟里昂在环境中不降解，会消耗、破坏臭氧层，导致对氟里昂使用、生产的限制和无氟冰箱的出现， 环境化学家利用化学和各种环境科学的一系列概念来帮助他们研究环境中化学物质的变化。 化学中重要的一般概念包括理解化学反应和方程式、溶液、单位、抽样和分析技术。
Environmental chemistry is the scientific study of the chemical and biochemical phenomena that occur in natural places. It should not be confused with green chemistry, which seeks to reduce potential pollution at its source. It can be defined as the study of the sources, reactions, transport, effects, and fates of chemical species in the air, soil, and water environments; and the effect of human activity and biological activity on these. Environmental chemistry is an interdisciplinary science that includes atmospheric, aquatic and soil chemistry, as well as heavily relying on analytical chemistry and being related to environmental and other areas of science. Environmental chemistry involves first understanding how the uncontaminated environment works, which chemicals in what concentrations are present naturally, and with what effects. Without this it would be impossible to accurately study the effects humans have on the environment through the release of chemicals. Environmental chemists draw traditional chemical concepts as well as sampling and analytical techniques.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 催化（catalysis）或催化作用，是利用催化剂参与，改变化学反应速率而不影响化学平衡的作用。广泛发生于无机物反应、有机物反应、生物体内反应。 许多化学工业要利用催化作用来获得需要的反应速率。催化也是一种化工单元过程，催化剂本身在反应中不会被消耗，但催化剂会改变反应速率，一催化剂亦可能参与复数的催化反应。正催化剂可加速反应；负催化剂或抑制剂则会与反应物反应进而降低化学反应。可提高催化剂活性的物质称为促进剂；降低催化剂活性者则称为催化毒。 相较于未催化的反应，同温度的催化反应拥有较低的活化能。催化剂可以借由结合反应物达到极化的效果，如酸催化剂之于羰基化合物的合成；催化剂也可产生非自然的反应中间物，如以四氧化锇催化烯烃的双羟基化中产生的锇酸盐酯；催化剂亦可造成反应物的裂解，如制氢时产生的单原子氢。 很多物质都可以做催化剂，在无机物反应中，通常利用酸、碱、金属或金属化合物作为催化剂，在有机物反应中多用有性的蛋白质分子——酶作为催化剂，生物体内许多化学反应都依赖酶来进行的。 催化反应可以发生在均相催化和多相催化中，也可以发生在复相催化中：
Catalysis (, kə-TAL-iss-iss) is the increase in rate of a chemical reaction due to an added substance known as a catalyst ( KAT-əl-ist). Catalysts are not consumed by the reaction and remain unchanged after the reaction. If the reaction is rapid and the catalyst is recycled quickly, a very small amount of catalyst often suffices; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. The rate increase occurs because the catalyst allows the reaction to occur by an alternative mechanism which may be much faster than the noncatalyzed mechanism. However the noncatalyzed mechanism does remain possible, so that the total rate (catalyzed plus noncatalyzed) can only increase in the presence of the catalyst and never decrease.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 量子力学（quantum mechanics）是物理学的分支学科。它描述原子尺度及原子尺度以下的自然行为和规律。 它是所有量子物理学的基础，包括量子化学、量子场论、量子技术和量子信息科学。 量子力学与相对论一起被认为是现代物理学的两大基本支柱。19世纪末，人们发现旧有的经典理论无法解释微观系统，于是经由物理学家的努力，在20世纪初创立量子力学，解释了这些现象。量子力学从根本上改变人类对物质结构及其相互作用的理解。除了透过广义相对论描写的引力外，迄今所有基本相互作用均可以在量子力学的框架内描述（量子场论）。 量子理论的重要应用包括宇宙学、量子化学、量子光学、量子计算、超导磁体、发光二极管、激光器、晶体管和半导体如微处理器等。 爱因斯坦可能是在科学文献中最先给出术语“量子力学”的物理学者。 量子力学逐渐从理论中兴起，用来解释与经典物理学不相符的观测结果，例如马克斯·普朗克在1900年解决黑体辐射问题，以及阿尔伯特·爱因斯坦1905年论文中能量与频率的对应关系，该论文解释了光电效应影响。 这些理解微观现象的早期尝试，现在被称为“旧量子论”，导致尼尔斯·玻尔、欧文·薛定谔、维尔纳·海森堡、马克斯·玻恩、保罗·狄拉克等人在1920年代中期全面发展了量子力学。 现代理论是用各种专门发展的数学形式体系来表达的。 其中之一，称为波函数的数学实体以概率幅的形式提供有关粒子能量、动量和其他物理特性的测量结果的信息。
Quantum mechanics, also known as quantum physics, is the fundamental physical theory that describes the behavior of matter and of light; the behaviors it models typically occur at and below the scale of atoms, and have often been described as counterintuitive. Its concepts and methods have been applied across many disciplines, including quantum chemistry, quantum biology, quantum field theory, quantum technology, and quantum information science. Quantum mechanics can describe many systems that classical physics cannot. Classical physics can describe many aspects of nature at an ordinary (macroscopic and (optical) microscopic) scale; however, it is insufficient for describing them at very small submicroscopic (atomic and subatomic) scales. Classical mechanics can be derived from quantum mechanics as an approximation that is valid at ordinary scales. Quantum systems have bound states that are quantized to discrete values of energy, momentum, angular momentum, and other quantities, in contrast to classical systems where these quantities can be measured continuously.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 在传统逻辑中，公理（古希腊语: ἀξίωμα, 德语、英语: Axiom）是没有经过证明，但被当作不证自明的一个命题。因此，其真实性被视为是理所当然的，且被当做演绎及推论其他（理论相关）事实的起点。当不断要求证明时，因果关系毕竟不能无限地追溯，而需停止于无需证明的公理。通常公理都很简单，且符合直觉，如“ a + b = b + a {\displaystyle a+b=b+a} ”。 不同的系统，会预计不同的公理。例如非欧几何的公理，和欧氏几何的公理就有一点不同；另外，集合论的选择公理在许多系统的建构中，也富有争议。有些系统坚持不预设选择公理。也有一些数学家在建构系统时，刻意排除掉皮亚诺公理中的数学归纳法，以确保所有的证明，都可以直接演算。 在数学中，公理这一词被用于两种相关但相异的意思之下——逻辑公理和非逻辑公理。在这两种意义之下，公理都是用来推导其他命题的起点。和定理不同，一个公理（除非有冗余的）不能被其他公理推导出来，否则它就不是起点本身，而是能够从起点得出的某种结果—可以干脆被归为定理了。 逻辑公理通常是被视为普遍为真的陈述（如 ( A ∧ B ) → A {\displaystyle (A\land B)\rightarrow A} ），而非逻辑公理（如 a + b = b + a {\displaystyle a+b=b+a} ）则实际上是在一特定数学理论（如算术）中的定义性的性质。在后者的意思之下，公理又可被称为“公设”。一般而言，非逻辑公理并不是一个不证自明的事实，而应该说是在建构一个数学理论的过程中被用来推导的一个形式逻辑表示式。要公理化一个知识系统，就是要去证明该系统的主张都可以由数目不多而又可明确理解的陈述（公理）推导出来。一般来说都有多种方法来公理化一个给定的数学领域。
An axiom, postulate, or assumption, is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments. The word comes from the Ancient Greek word ἀξίωμα (axíōma), meaning 'that which is thought worthy or fit' or 'that which commends itself as evident'. The precise definition varies across fields of study. In classical philosophy, an axiom is a statement that is so evident or well-established, that it is accepted without controversy or question. In modern logic, an axiom is a premise or starting point for reasoning. In mathematics, an axiom may be a "logical axiom" or a "non-logical axiom". Logical axioms are taken to be true within the system of logic they define and are often shown in symbolic form (e.g., (A and B) implies A), while non-logical axioms are substantive assertions about the elements of the domain of a specific mathematical theory, for example a + 0 = a in integer arithmetic. Non-logical axioms may also be called "postulates", "assumptions" or "proper axioms".
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 边界层，又称附面层是一个流体力学名词，表示流体中紧接着管壁或其他固定表面的部分。边界层是由黏滞力产生的效应，和雷诺数Re有关。 一般提到的边界层是指速度的边界层。在边界层外，流体的速度接近定值，不随位置而变化。在边界层内，在固定表面上流速为0，距固定表面越远，速度会趋近一定值。
In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condition (zero velocity at the wall). The flow velocity then monotonically increases above the surface until it returns to the bulk flow velocity. The thin layer consisting of fluid whose velocity has not yet returned to the bulk flow velocity is called the velocity boundary layer. The air next to a human is heated, resulting in gravity-induced convective airflow, which results in both a velocity and thermal boundary layer. A breeze disrupts the boundary layer, and hair and clothing protect it, making the human feel cooler or warmer.
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Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
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