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Abstract An ultra‐fast electrochemical capacitor (EC) designed for efficient ripple current smoothing was fabricated using vertically oriented MoS2(VOM) nanoflakes deposited on freestanding carbonized cellulose (CC) sheets as electrodes. The daily used cellulose tissue sheets were transformed into electrode scaffolds through a rapid pyrolysis process within a preheated furnace, on which VOM nanoflakes were formed in a conventional hydrothermal process. With these ~10 μm thick VOM‐CC electrodes, ultrafast ECs with tunable frequency response and specific capacitance density were fabricated. The ECs with a cell‐level areal capacitance density of 0.8 mF/cm2at 120 Hz were demonstrated for ripple current filtering from 60 Hz to 60 kHz. At a lower frequency response level, EC cell with a large capacitance density of 4.8 mF/cm2was also demonstrated. With the facile and easily scaled up process to producing the nanostructured electrode, the miniaturized VOM‐CC based ECs have the potential to substitute the bulky aluminum electrolytic capacitors for current smoothing and pulse power applications.
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A molecular orbital selection approach for fast calculations of specific rotation with density functional theory
Abstract In this work, we describe a simple approach to select the most important molecular orbitals (MOs) to compute the optical rotation tensor through linear response (LR) Kohn‐Sham density functional theory (KS‐DFT). Taking advantage of the iterative nature of the algorithms commonly used to solve the LR equations, we select the MOs with contributions to the guess perturbed density that are larger than a certain threshold and solve the LR equations with the selected MOs only. We propose two criteria for the selection, and two definitions of the selection threshold. We then test the approach with two functionals (B3LYP and CAM‐B3LYP) and two basis sets (aug‐cc‐pVDZ and aug‐cc‐pVTZ) on a set of 51 organic molecules with specific rotation spanning five orders of magnitude, 100–104deg (dm−1(g/mL)−1). We show that this approach indeed can provide very accurate values of specific rotation with estimated speedup that ranges from 2 to 8× with the most conservative selection criterion, and up to 20 to 30× with the intermediate criterion.
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- Award ID(s):
- 1650942
- PAR ID:
- 10458835
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chirality
- Volume:
- 32
- Issue:
- 3
- ISSN:
- 0899-0042
- Page Range / eLocation ID:
- p. 243-253
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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