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The second law of thermodynamics states [8] [9] that T surr d S ≥ δ Q , {\displaystyle T_{\text{surr}}dS\geq \delta Q,} where δ Q {\displaystyle \delta Q} is the amount of energy the system gains by heating, T surr {\displaystyle T_{\text{surr}}} is the temperature of the surroundings, and d S {\displaystyle dS} is the change in entropy.
[1] [2] At chemical equilibrium or in phase equilibrium, the total sum of the product of chemical potentials and stoichiometric coefficients is zero, as the free energy is at a minimum. [3] [4] [5] In a system in diffusion equilibrium, the chemical potential of any chemical species is uniformly the same everywhere throughout the system. [6]
At room temperature, the graphene/n-Si photodetector with interfacial oxide exhibits a specific detectivity up to 5.77 × 10 13 cm Hz 1/2 W 2 at the peak wavelength of 890 nm in vacuum. In addition, the improved graphene/n-Si heterojunction photodetectors possess high responsivity of 0.73 A W −1 and high photo-to-dark current ratio of ≈107.
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions.The results are presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio.
In a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system. [1] This state results when the forward reaction proceeds at the same rate as the reverse ...
The ether normally has a water content of 1.5–2%; in absence of water, ethylene oxide polymerizes. [37] Halohydrins can also be obtained by passing ethylene oxide through aqueous solutions of metal halides: [33] 2 (CH 2 CH 2)O + CuCl 2 + 2 H 2 O → 2 HO–CH 2 CH 2 –Cl + Cu(OH) 2 ↓
where D is the diffusion coefficient, Φ is porosity, n is the concentration, m > 0 (usually m > 1, the case m = 1 corresponds to Fick's law). Care must be taken to properly account for the porosity (Φ) of the porous medium in both the flux terms and the accumulation terms. [22]
For example, the mobile phase composition may be kept constant at 5% acetonitrile for 1–3 min, followed by a linear change up to 95% acetonitrile. [ citation needed ] The chosen composition of the mobile phase depends on the intensity of interactions between various sample components ("analytes") and stationary phase ( e.g. , hydrophobic ...