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Xiang Xi, Mi Lin, Wenbiao Qiu, Zhengbiao Ouyang, Qiong Wang, Qiang Liu
We propose a type of polarization-independent circulator based on ferrite and plasma materials in a two-dimensional photonic crystal (PhC) slab. First, on the basis of analyzing the wave equations in ferrite and plasma materials, TE and TM circulators are realized with ferrite and plasma in PhCs, respectively. Then, by properly combining these two types of circulators together, a polarization-independent circulator is achieved and investigated. The results show that, for both polarizations, the insertion loss and isolation for the polarization-independent circulator are less than 0...
May 18, 2018: Scientific Reports
Yuzhi Zhou, Han Wang, Yu Liu, Xingyu Gao, Haifeng Song
The Kerker preconditioner, based on the dielectric function of homogeneous electron gas, is designed to accelerate the self-consistent field (SCF) iteration in the density functional theory calculations. However, a question still remains regarding its applicability to the inhomogeneous systems. We develop a modified Kerker preconditioning scheme which captures the long-range screening behavior of inhomogeneous systems and thus improves the SCF convergence. The effectiveness and efficiency is shown by the tests on long-z slabs of metals, insulators, and metal-insulator contacts...
March 2018: Physical Review. E
Yan Zhao, Sarawuth Chaimool
In this paper, we apply a relativistic finite-difference time-domain (FDTD) method by using the Lorentz transformation to analyze metamaterials moving at a high speed. As an example, we consider a slab of left-handed metmaterial (LHM) with both relative permittivity and permeability equal to -1. Simulation results show that when the LHM slab moves at a high speed, its electromagnetic responses are drastically different from the static case. Specifically, when the LHM slab moves toward the source, for the case of normal incidence, there exists a special velocity at which fields experience a zero spatial phase delay through the LHM slab; while for the oblique incidence, above a certain velocity fields inside the LHM become evanescent...
May 16, 2018: Scientific Reports
Tirta Rona Mayangsari, Jae-Min Park, Luchana Lamierza Yusup, Jiyeon Gu, Jin-Hyuk Yoo, Heon-Do Kim, Won-Jun Lee
We report the catalyzed atomic layer deposition (ALD) of silicon oxide using Si2 Cl6 , H2 O, and various alkylamines. The density functional theory (DFT) calculations using periodic slab model of the SiO2 surface were performed for the selection of alternative Lewis-base catalysts with high catalytic activities. During the first half-reaction, the catalysts with less steric hindrance such as pyridine would be more effective than bulky alkylamines despite lower nucleophilicity. On the other hand, during the second half-reaction, the catalysts with a high nucleophilicity such as triethylamine (Et3 N) would be more efficient because the steric hindrance is less critical...
May 16, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Rodrigo Rocha Maia, Dayane Oliveira, Tracy D'Antonio, Fang Qian, Frederick Skiff
Objectives: To evaluate and compare light-transmittance in dental tissues and dental composite restorations using the incremental double-layer technique with varying layer thickness. Materials and Methods: B1-colored natural teeth slabs were compared to dental restoration build-ups with A2D and B1E-colored nanofilled, supra-nanofilled, microfilled, and microhybrid composites. The enamel layer varied from 0.3, 0.5, or 1.2 mm thick, and the dentin layer was varied to provide a standardized 3...
May 2018: Restorative Dentistry & Endodontics
Nadir Ghichi, Chawki Bensouici, Ali Benboudiaf, Yacine DJebli, Hocine Merazig
The title Schiff base compounds, C20 H16 ClNO2 (I) and C24 H22 N2 O2 (II), were synthesized via the condensation reaction of 2-amino-4-chloro-phenol for (I), and 2-(2,3-di-hydro-1 H -indol-3-yl)ethan-1-amine for (II), with 4-benz-yloxy-2-hy-droxy-benzaldehyde. In both compounds, the configuration about the C=N imine bond is E . Neither mol-ecule is planar. In (I), the central benzene ring makes dihedral angles of 49.91 (12) and 53.52 (11)° with the outer phenyl and chloro-phenyl rings, respectively. In (II), the central benzene ring makes dihedral angles of 89...
April 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Mir Abolfazl Naziri, Ertan Şahin, Tuncer Hökelek
The asymmetric unit of the title aroyl hydrazone Schiff base salt, C13 H12 N3 O2 + ·N O3 - , consists of one mol-ecular cation in the keto tautomeric form, adopting an E configuration with respect to the azomethine bond, and one nitrate anion. The two units are linked via an N-H⋯O hydrogen bond. The mol-ecule overall is non-planar, with the pyridinium and benzene rings being inclined to each other by 4.21 (4)°. In the crystal, cations and anions are linked via inter-molecular O-H⋯O and bifurcated N-H⋯O hydrogen bonds, forming a two-dimensional network parallel to (101)...
March 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Alessandro Esposito, Sofia Silva, Jorge Oliveira, Joana Lencart, João Santos
BACKGROUND: IMRT provides higher dose conformation to the target and dose sparing to surrounding tissues than 3DCRT. Monte Carlo method in Medical Physics is not a novelty to approach dosimetric problems. A new PENELOPE based code named PRIMO recently was published. The most intriguing features of PRIMO are the user-friendly approach, the stand-alone property and the built-in definition of different linear accelerators models. Nevertheless, IMRT simulations are not yet implemented. METHODS: A Varian Trilogy with a Millennium120 MLC and a Varian Novalis with 120HD MLC were studied...
May 15, 2018: Radiation Oncology
Sonja M Schellhammer, Sebastian Gantz, Armin Lühr, Bradley M Oborn, Michael Bussmann, Aswin L Hoffmann
PURPOSE: Given its sensitivity to anatomical variations, proton therapy is expected to benefit greatly from integration with magnetic resonance imaging for on-line anatomy monitoring during irradiation. Such an integration raises several challenges, as both systems mutually interact. The proton beam will experience quasi-continuous energy loss and energy-dependent electromagnetic deflection at the same time, giving rise to a deflected beam trajectory and an altered dose distribution with a displaced Bragg peak...
May 15, 2018: Medical Physics
S G Castillo-López, N M Makarov, F Pérez-Rodríguez
The resonant quantization of Landau damping in far-infrared absorption spectra of metal nano-thin films is predicted within the Kubo formalism. Specifically, it is found that the discretization of the electromagnetic and electron wave numbers inside a metal nanoslab produces quantum nonlocal resonances well-resolved at slab thicknesses smaller than the electromagnetic skin depth. Landau damping manifests itself precisely as such resonances, tracing the spectral curve obtained within the semiclassical Boltzmann approach...
May 15, 2018: Optics Letters
Kristina Bagnell, Anthony Klee, Peter J Delfyett, Jason J Plant, Paul W Juodawlkis
An optical frequency comb with mode spacing of 10 GHz operating in the c-band is produced from a harmonically mode-locked laser using a slab-coupled optical waveguide amplifier device with a fiber-coupled external cavity. An intracavity Fabry-Perot etalon serves as a high finesse optical filter for supermode suppression and as the reference for cavity length stabilization using a multi-combline Pound-Drever-Hall setup. The Allan deviation of a single optical combline near 193.4 THz is measured via a heterodyne beat with a cavity stabilized cw laser and reaches a minimum fractional frequency deviation of 3×10-13 at τ=30  ms...
May 15, 2018: Optics Letters
Liang Tian, Fei Wang, Yuanda Wu, Yunji Yi, Xiaoqiang Sun, Daming Zhang
A polymer/silica hybrid integration add-drop filter based on a grating-assisted contradirectional coupler fabricated through simple and low-cost contact lithography is proposed. First, the structure pattern of the add-drop filter was formed in the lower silica cladding by contact lithography and inductively coupled plasma (ICP) etching. Then an SU-8 film was fabricated on top of it by a spin-coating method, and an inverted-rib waveguide structure was formed. Next, the slab layer of the inverted-rib waveguide was removed by ICP etching...
May 15, 2018: Optics Letters
Akira Hasegawa
I reviewed studies on the inhomogeneous seismic structure of the mantle wedge in subduction zones, in relation to corner flow and its implications for arc magmatism. Seismic studies in Tohoku clearly imaged the descending flow portion of the corner flow as a thin seismic low-velocity layer right above the slab. Slab-derived H2 O is fixed to the layer as hydrous minerals, which are brought down by the slab and eventually decompose. The released H2 O rises and encounters the ascending flow, formed to fill the gap caused by the descending flow...
2018: Proceedings of the Japan Academy. Series B, Physical and Biological Sciences
Vittorio Calzolari, Luca De Mattia, Stefano Indiani, Martino Crosato, Alberto Furlanetto, Claudia Licciardello, Paolo Antonio Maria Squasi, Zoran Olivari
OBJECTIVES: In an in vitro model, the authors tested the hypotheses that: 1) lesion dimensions correlate with lesion size index (LSI); and 2) LSI could predict lesion dimensions better than power, contact force (CF), and force-time integral (FTI). BACKGROUND: When performing radiofrequency (RF) catheter ablation for cardiac arrhythmias, reliable predictors of lesion quality are lacking. The LSI is a multiparametric index incorporating time, power, CF, and impedance recorded during ablation...
October 2017: JACC. Clinical Electrophysiology
Renata Siqueira Scatolin, Vivian Colucci, Taísa Penazzo Lepri, Adílis Kalina de Alexandria, Lucianne Cople Maia, Rodrigo Galo, Maria Cristina Borsatto, Silmara Aparecida Milori Corona
Literature has reported positive results regarding the use of lasers in the control of erosive lesions; however, evaluating whether they are effective in the control of the progression of erosive/abrasive lesions is important. Objectives This study aimed to evaluate the effect of the Er:YAG laser irradiation in controlling the progression of erosion associated with abrasive lesions in enamel. Material and methods Bovine incisors were sectioned, flattened and polished. Forty-eight enamel slabs were subjected to treatment in an intraoral phase...
2018: Journal of Applied Oral Science: Revista FOB
Lamberto Widesott, Stefano Lorentini, Francesco Fracchiolla, Paolo Farace, Marco Schwarz
validation of a commercial Monte Carlo (MC) algorithm (RayStation ver6.0.024) for the treatment of brain tumours with pencil beam scanning (PBS) proton therapy, comparing it via measurements and analytical calculations in clinically realistic scenarios. 
 Methods: For the measurements a 2D ion chamber array detector (MatriXX PT)) was placed underneath the following targets: 1) anthropomorphic head phantom (with two different thickness) and 2) a biological sample (i.e. half lamb's head). In addition, we compared the MC dose engine vs...
May 4, 2018: Physics in Medicine and Biology
Peng-Fei Wang, Hanshen Xin, Tong-Tong Zuo, Qinghao Li, Xinan Yang, Ya-Xia Yin, Xike Gao, Xiqian Yu, Yu-Guo Guo
O3-type layered sodium oxides (NaMO2, M = transition metal) commonly exhibit O3-P3 phase transition occurring at a low redox voltage of ≈ 3V versus Na+/Na during sodium extraction and insertion, incurring almost 50% of their total capacity lies at this low voltage region and insufficient energy density as cathode materials for Na-ion batteries (NIBs). Therefore raising the phase-transition voltage by reasonable structure modulation has always been facing a severe challenge in the development of high-voltage O3-type cathodes...
May 2, 2018: Angewandte Chemie
Benoit Nennig, Rémy Binois, Nicolas Dauchez, Emmanuel Perrey-Debain, Félix Foucart
Due to the manufacturing process, some fibrous materials like glasswool may be transversely isotropic (TI): fibers are mostly parallel to a plane of isotropy within which material properties are identical in all directions whereas properties are different along the transverse direction. The behavior of TI fibrous material is well described by the TI Biot's model, but it requires one to measure several mechanical parameters and to solve the TI Biot's equations. This paper presents an equivalent fluid model that can be suitable for TI materials under certain assumptions...
April 2018: Journal of the Acoustical Society of America
Wentao Li, Chi Yuen Pak, Ying-Lung Steve Tse
Understanding gas sorption by water in the atmosphere is an active research area because the gases can significantly alter the radiation and chemical properties of the atmosphere. We attempt to elucidate the molecular details of the gas sorption of water and three common atmospheric gases (N2 O5 , SO2 , and O3 ) by water droplets/slabs in molecular dynamics simulations. The system size effects are investigated, and we show that the calculated solvation free energy decreases linearly as a function of the reciprocal of the number of water molecules from 1/215 to 1/1000 in both the slab and the droplet systems...
April 28, 2018: Journal of Chemical Physics
Huiyu Li, Liwei Fu, Karsten Frenner, Wolfgang Osten
We experimentally demonstrate a novel design of a cascaded plasmonic superlens, which can directly image subwavelength objects with magnification in the far field at visible wavelengths. The lens consists of two cascaded plasmonic slabs. One is a plasmonic metasurface used for near field coupling, and the other one is a planar plasmonic lens used for phase compensation and thus image magnification. First, we show numerical calculations about the performance of the lens. Based on these results we then describe the fabrication of both sub-structures and their combination...
April 16, 2018: Optics Express
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