Advanced Technical Ceramics Directory and Databook

Hussey, Bob; Wilson, J. O.

doi:10.1007/978-1-4419-8662-7

Cited by 19 publications

(11 citation statements)

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“…The permittivity of the perovskite well is based on the reported values for bulk materials: 25.5 for methylammonium lead-bromide 52 , 30 for lead-bromide 69 , and 41 for cesium lead-bromide 70 . We set the permittivity of the barrier to be 4.08, based on the permittivity of hexylamine 69 ; of PMMA to 3.0 71 ; of SiO 2 to 4.2 69 ; of ZrO 2 to 12.5 69 ; and of Al 2 O 3 to 9.1 72 . The field strengths over the perovskite and within the wells are provided in Supplementary Table 1 .…”

Section: Methodsmentioning

confidence: 99%

The quantum-confined Stark effect in layered hybrid perovskites mediated by orientational polarizability of confined dipoles

et al. 2018

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The quantum-confined Stark effect (QCSE) is an established optical modulation mechanism, yet top-performing modulators harnessing it rely on costly fabrication processes. Here, we present large modulation amplitudes for solution-processed layered hybrid perovskites and a modulation mechanism related to the orientational polarizability of dipolar cations confined within these self-assembled quantum wells. We report an anomalous (blue-shifting) QCSE for layers that contain methylammonium cations, in contrast with cesium-containing layers that show normal (red-shifting) behavior. We attribute the blue-shifts to an extraordinary diminution in the exciton binding energy that arises from an augmented separation of the electron and hole wavefunctions caused by the orientational response of the dipolar cations. The absorption coefficient changes, realized by either the red- or blue-shifts, are the strongest among solution-processed materials at room temperature and are comparable to those exhibited in the highest-performing epitaxial compound semiconductor heterostructures.

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Section: Methodsmentioning

confidence: 99%

The quantum-confined Stark effect in layered hybrid perovskites mediated by orientational polarizability of confined dipoles

et al. 2018

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“…The values of ε SiC = 10.2, ε mullite = 5.8, and n SiC = 2.55, n mullite = 1.654 for SiC and mullite are taken from literature and Hamaker constants were calculated by taking relaxation frequency value as ω = 2 × 10 16 rad/s . From the known concentration of the electrolyte, the value of “κ” for the SiC‐mullite system was determined to be 0.803 × 10 9 /m.…”

Section: Resultsmentioning

confidence: 99%

Dispersion of SiC powder suspension in mullite sol and influence on properties of sintered ceramics

Baitalik

Kayal

2017

Int J Applied Ceramic Tech

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The dispersion behavior of SiC powders in various concentration of mullite sol was studied by zeta potential, rheological, and sedimentation measurements.Effect of pH, sol concentration, solid loading on the rheological properties are discussed in detail. The lowest viscosity and sedimentation was obtained for 45 wt% SiC powders dispersed in 15 wt% mullite sol, at pH~2. The adsorption isotherms belong to Langmuir type and optimum concentration of mullite for maximum dispersion was found to be~0.036 g/m 2 . The stabilization mechanism of SiC powder into mullite precursor sol was explained by Derjaguin-Landau-Vervey-Overbeek (DLVO) theory. Coating was confirmed by transmittance electron microscopy and energy-dispersive X-ray spectroscopy analysis. Further sintering of the mullite-coated SiC powder compact at 1300°C produced porous SiC ceramic with porosity~40 vol% and pore diameter~3 lm. The corrosion behavior of the ceramics was studied in strong acid medium at 90°C and compared with the ceramics obtained from uncoated SiC powder.

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“…Tool-specimen friction coefficient is assumed to be 0.2 (the friction coefficient of most ceramics is in the range of 0.1-0.3). 37 The machining sample in the simulation has a width of 2 mm and a height of 1 mm, and the assembly contains 9623 particles.…”

Section: Numerical Modeling Of the Orthogonal Cutting Processmentioning

confidence: 99%

Dynamic modeling of the turning process of slip-cast fused silica ceramics using the discrete element method

Roostai

Movahhedy

2019

Proceedings of the Institution of Mechanical Engineers, Part B:

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Simulation of brittle regime machining of materials (such as ceramics) is often difficult because of the complex material removal mechanisms involved. In this study, the discrete element method is used to simulate the dynamic process for machining of slip-cast fused silica ceramics. Flat-joint contact model is exploited to model contacts between particles in synthetic discrete element method models. This contact model is suitable for modeling of brittle materials with high ratios (higher than 10) of unconfined compressive strength to tensile strength. The discrete element method has the ability to simulate initiation, propagation, and coalescence of cracks leading to chip formation in the brittle regime of cutting. Applying the discrete element method, the influences of operating conditions on the creation of surface/subsurface damages, chip formation, and cutting forces are studied. It is shown that the parameters of the material model determined from conventional calibration tests do not provide quantitatively accurate prediction of cutting forces. As such, model updating is carried out using the forces obtained in the cutting experiments, and the numerical results are verified against experimental cutting forces. The differences between experimental and numerical machining forces are in the range of 10%–30%. Finally, the results of discrete element method simulations reveal that the nature of micro-crack propagation is brittle in the machining process of ceramics.

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Advanced Technical Ceramics Directory and Databook

Cited by 19 publications

References 0 publications

The quantum-confined Stark effect in layered hybrid perovskites mediated by orientational polarizability of confined dipoles

The quantum-confined Stark effect in layered hybrid perovskites mediated by orientational polarizability of confined dipoles

Dispersion of SiC powder suspension in mullite sol and influence on properties of sintered ceramics

Dynamic modeling of the turning process of slip-cast fused silica ceramics using the discrete element method

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