热力学第零定律

触变性和流变性描述的是粘度随时间的变化。触变性流体的粘度在恒定的剪切应力下会随时间降低（例如，酸奶在搅拌时会变得更稀）。流变性（或抗触变性）流体的粘度在恒定的剪切应力下会随时间增加（例如，某些润滑剂）。这些效应是可逆的；流体在静置一段时间后会恢复到原始状态。

A quantum mechanical phenomenon where a wavefunction can propagate through a potential energy barrier. Classically, a particle lacking sufficient energy to surmount a barrier would be reflected. However, due to the wave-like nature of particles, there is a non-zero probability that the particle can appear on the other side of the barrier, effectively 'tunneling' through it.

A non-Newtonian fluid is one whose viscosity changes under an applied shear stress. Unlike a Newtonian fluid where viscosity is constant, its flow properties are not described by a linear relationship between shear stress ([latex]\tau[/latex]) and shear rate ([latex]\dot{\gamma}[/latex]). This dependency can manifest as shear-thinning (viscosity decreases with stress) or shear-thickening (viscosity increases with stress).

普朗克轨迹是白炽灯黑体辐射器的颜色随其温度变化在色度空间中的变化路径。它通常绘制在CIE 1931 xy色度图上，呈现为一条从红橙色区域到蓝白色区域的圆弧。它是定义色温的基本参考。

紫外线光谱通常细分为UVA（400-315纳米）、UVB（315-280纳米）和UVC（280-100纳米）。UVA，即长波紫外线，能量最低，穿透皮肤最深。UVB，即中波紫外线，会导致晒伤，对维生素D的合成至关重要。UVC，即短波紫外线，能量最高，具有杀菌作用，但会被地球大气层完全吸收。

In quantum mechanics, momentum is an observable represented by a vector operator. In the position basis, the momentum operator is given by [latex]\hat{\vec{p}} = -i\hbar\nabla[/latex], where [latex]\hbar[/latex] is the reduced Planck constant and [latex]\nabla[/latex] is the gradient operator. The conservation of momentum corresponds to the fact that the Hamiltonian operator commutes with the momentum operator, [latex][\hat{H}, \hat{\vec{p}}] = 0[/latex], for a system with translational symmetry.

It is impossible to simultaneously know with perfect accuracy certain pairs of complementary physical properties of a particle. The most common example is the position [latex]x[/latex] and momentum [latex]p[/latex]. The principle states that the product of their uncertainties, [latex]\Delta x[/latex] and [latex]\Delta p[/latex], must be greater than or equal to a specific value: [latex]\Delta x \Delta p \ge \frac{\hbar}{2}[/latex].

发光二极管是一种半导体PN结。当施加合适的正向电压时，n区的电子和p区的空穴被注入到耗尽区。当它们复合时，会释放能量。在直接带隙半导体中，这种能量会高效地以光子的形式释放出来，这一过程称为电致发光。

Electrochemical potential, [latex]\bar{\mu}_i[/latex], quantifies the total energy of a charged species `i` in a system. It combines the chemical potential, [latex]\mu_i[/latex], which accounts for concentration and intrinsic properties, with the electrostatic potential energy, [latex]z_i F \phi[/latex]. The formula is [latex]\bar{\mu}_i = \mu_i + z_i F \phi[/latex], where [latex]z_i[/latex] is the ion's charge, [latex]F[/latex] is the Faraday constant, and [latex]phi[/latex] is the local electric potential.

相关色温 (CCT) 是衡量非理想黑体辐射光源（例如 LED 或荧光灯）色温的指标。它是指与光源颜色感知最接近的普朗克辐射体的温度。这种“接近度”是通过在普朗克轨迹上找到距离光源色度坐标最近的点来确定的。

完美反射漫射体，也称为完美白光，是一种理论上的理想表面，在比色法和分光光度法中用作参考标准。其定义为能够 100% 反射可见光谱中所有波长的入射光，并实现完美漫反射（朗伯反射）的表面，这意味着其亮度在任何视角下都均匀一致。

A superacid is an acid with an acidity greater than that of 100% pure sulfuric acid. The conventional pH scale is inadequate for these media. Instead, their acidity is measured using the Hammett acidity function, [latex]H_0[/latex]. This function is based on the protonation of weak indicator bases and is defined as [latex]H_0 = pK_{BH^+} - \log\left(\frac{[BH^+]}{[B]}}\right)[/latex].