Optical properties of monolayer NbS2 suspensions

1988 ◽  
Vol 66 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Z. M. Li ◽  
B. Bergersen ◽  
P. Palffy-Muhoray ◽  
D. Beigie
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Dielectric Constant ◽  
Bulk Material ◽  
Separate Study ◽  
Dominant Mechanism ◽  
Extinction Coefficients ◽  
Optical And Magnetic Properties ◽  
Reflectivity Data ◽  
Experimental Ratio

We present a theory for the anisotropic optical and magnetic properties of monolayer NbS2 platelets suspended in water and oriented in a magnetic field. We compare experimental data obtained by Liu and Frindt and calculated properties using a dielectric function obtained from a Drude–Lorentz fit to reflectivity data for the bulk material. The anisotropic magnetic susceptibility of the material allows a separate study of the extinction coefficients of light with polarizations perpendicular and parallel to the flake plane. We estimate the contributions from scattering and absorption using the fitted dielectric constant; and we find that for monolayer flakes, absorption should be the dominant mechanism. We also estimate the effects of local-field corrections on absorption and scattering to be small. A puzzling feature is that the experimental ratio of the optical anisotropy for the extinction coefficients fails to satisfy a predicted 2:1 ratio suggested by symmetry considerations.

scholarly journals A Magneto-Active Elastomer Crawler with Peristaltic and Caterpillar Locomotion Patterns

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 74
Author(s):  
Tsam Lung You ◽  
Hemma Philamore ◽  
Fumitoshi Matsuno
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Mathematical Models ◽  
Confined Spaces ◽  
Low Mass ◽  
Structural Simplicity

In this work we present a soft crawler fabricated using a magneto-active elastomer. The crawler is controlled by an external magnetic field to produce two locomotion patterns: peristaltic and caterpillar crawling. Due to its structural simplicity, low mass, wirelessly controlled actuation and compliant body the design of this crawler has the potential to address the key challenges faced by existing crawling robots. Experimental data were gathered to evaluate the performance of the crawler locomotion in a pipe. The results validated the mathematical models proposed to estimate the distance traveled by the crawler. The crawler shows potential for use in exploration of confined spaces.

scholarly journals A mesoscopic model for compression of granular materials

2018 ◽  
Vol 183 ◽  
pp. 01054
Author(s):  
Elisha Rejovitzky
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Granular Materials ◽  
Mechanical Model ◽  
Sound Speed ◽  
Bulk Material ◽  
High Sensitivity ◽  
Water Fraction ◽  
Protective Structures ◽  
Solid Spheres

The design of protective structures often requires numerical modeling of shock-wave propagation in the surrounding soils. Properties of the soil such as grain-grading and water-fraction may vary spatially around a structure and among different sites. To better understand how these properties affect wave propagation we study how the meso-structure of soils affects their equation of state (EOS). In this work we present a meso-mechanical model for granular materials based on a simple representation of the grains as solid spheres. Grain-grading is prescribed, and a packing algorithm is used to obtain periodic grain morphologies of tightly packed randomly distributed spheres. The model is calibrated by using experimental data of sand compaction and sound-speed measurements from the literature. We study the effects of graingrading and show that the pressures at low strains exhibit high sensitivity to the level of connectivity between grains. At high strains, the EOS of the bulk material of the grains dominates the behavior of the EOS of the granular material.

scholarly journals On the Fluctuation Induced Excess Conductivity in Stainless Steel Sheathed MgB2 Tapes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Suchitra Rajput ◽  
Sujeet Chaudhary
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Stainless Steel ◽  
Coherence Length ◽  
Three Dimensional ◽  
Excess Conductivity ◽  
Scaling Functions ◽  
Critical Fluctuations ◽  
Scaling Models

We report on the analyses of fluctuation induced excess conductivity in the - behavior in the in situ prepared MgB2 tapes. The scaling functions for critical fluctuations are employed to investigate the excess conductivity of these tapes around transition. Two scaling models for excess conductivity in the absence of magnetic field, namely, first, Aslamazov and Larkin model, second, Lawrence and Doniach model, have been employed for the study. Fitting the experimental - data with these models indicates the three-dimensional nature of conduction of the carriers as opposed to the 2D character exhibited by the HTSCs. The estimated amplitude of coherence length from the fitted model is ~21 Å.

Contributions to Silicon-Hydrogen Bond-Stretching Frequency in Amorphous Si Alloys

1992 ◽  
Vol 258 ◽  
Author(s):  
Z. Jing ◽  
J. L. Whitten ◽  
G. Lucovsky
Keyword(s):  
Experimental Data ◽  
Hydrogen Bond ◽  
Dielectric Constant ◽  
Ab Initio ◽  
Effective Dielectric Constant ◽  
Bond Energies ◽  
Calculated Frequency ◽  
Bond Stretching ◽  
Amorphous Si ◽  
Good Agreement

ABSTRACTWe have performed ab initio calculations and determined the bond-energies and vibrational frequencies of Si-H groups that are: i) attached to Si-atoms as their immediate, and also more distant neighbors; and ii) attached to three O-atoms as their immediate neighbors, but are connected to an all Si-atom matrix. These arrangements simulate bonding geometries on Si surfaces, and the calculated frequency for i) is in good agreement with that of an Si-H group on an Si surface. To compare these results with a-Si:H alloys it is necessary to take into account an additional factor: the effective dielectric constant of the host. We show how to do this, demonstrating the way results of the ab initio calculations should then be compared with experimental data.

Residual Stress Measurement and Simulation of 3C-SiC Single and Poly Crystal Cantilevers

2010 ◽  
Vol 645-648 ◽  
pp. 865-868 ◽  
Author(s):  
Ruggero Anzalone ◽  
Massimo Camarda ◽  
Daniel Alquier ◽  
M. Italia ◽  
Andrea Severino ◽  
...  
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Stress Measurement ◽  
Bulk Material ◽  
Raman Shift ◽  
Silicon Substrates ◽  
Free Standing ◽  
Element Analysis ◽  
Micro Fabrication ◽  
Sic Films

The fabrication of SiC MEMS-based sensors requires new processes able to realize microstructures on either bulk material or on the SiC surface. The hetero-epitaxial growth of 3C-SiC on silicon substrates allows one to overcome the traditional limitations of SiC micro-fabrication. In this work a comparison between single crystal and poly crystal 3C-SiC micro-machined structures will be presented. The free-standing structures realized (cantilevers and membrane) are also a suitable method for residual field stress investigation in 3C-SiC films. Measurement of the Raman shift indicates that the mono and poly-crystal 3C-SiC structures release the stress in different ways. Finite element analysis was performed to determine the stress field inside the films and provided a good fit to the experimental data. A comprehensive experimental and theoretical study of 3C-SiC MEMS structures has been performed and is presented.

Optical and Magnetic Properties of Silica Implanted with N+ and Fe+

1995 ◽  
Vol 396 ◽  
Author(s):  
T. Isobe ◽  
R.A. Weeks ◽  
R.A. Zuhr
Keyword(s):  
Magnetic Field ◽  
Relative Intensity ◽  
Chemical Interaction ◽  
Resonance Field ◽  
Magnetic Interaction ◽  
Atomic Ratio ◽  
Resonance Absorption ◽  
Iron Nitrides ◽  
Optical And Magnetic Properties ◽  
Different Doses

AbstractSilica platelets (Corning 7940) were implanted sequentially with N at 52 keV to different doses ranging from 0 to 1.2×l017 ions cm2 and then with Fe at 160 keV to a dose of 6×10 ions cm2. The optical absorption decreased with increasing N1 dose at photon energies ranging from 1.4 eV to 6.5 eV. The relative intensity, S(0°), of the ferromagnetic resonance absorption and its resonance field, H(0°), at θ = 0° were larger than S(90°) and H,(90°) at 0 = 90°, where Θ is the angle between the applied magnetic field and the normal to the implanted surface. The maximum values of S(0°) and S(90°) were observed near the N/Fe atomic ratio of 0.2. At the similar atomic ratio, the differential relative intensity, S(0°)- S(90°), and the differential resonance field, H,(0°)-H,(90°). associated with the degree of magnetic interaction between the produced compounds, also showed maxima. We conclude that sequential ion-implantation of N1 and Fe1 into silica causes a chemical interaction to produce iron nitrides.

scholarly journals High Frequency Magnetoimpedance of FeNi/Cu/FeNi Sensitive Elements with Different Geometries

2009 ◽  
Vol 152-153 ◽  
pp. 373-376 ◽  
Author(s):  
Stanislav O. Volchkov ◽  
Andrey V. Svalov ◽  
G.V. Kurlyandskaya
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Finite Elements ◽  
Magnetic Anisotropy ◽  
Constant Magnetic Field ◽  
High Frequency ◽  
Complex Impedance ◽  
Rf Sputtering ◽  
Frequency Range

In this work magnetoimpedance (MI) behaviour was studied experimentally for Fe19Ni81(175 nm)/Cu(350 nm)/Fe19Ni81(175 nm) sensitive elements deposited by rf-sputtering. A constant magnetic field was applied in plane of the sandwiches during deposition perpendicular to the Cu-lead in order to induce a magnetic anisotropy. Sandwiches with different width (w) of FeNi parts were obtained. The complex impedance was measured as a function of the external magnetic field for a frequency range of 1 MHz to 700 MHz for MI elements with different geometries. Some of MI experimental data are comparatively analysed with finite elements numerical calculations data. The obtained results can be useful for optimization of the design of miniaturized MI detectors.

scholarly journals Density and Viscosity of LiCl, LiBr, LiI and Kcl in Aqueous Methanol at 313.15K

2021 ◽  
Vol 37 (5) ◽  
pp. 1083-1090
Author(s):  
V. V. Kadam ◽  
A. B. Nikumbh ◽  
T. B. Pawar ◽  
V. A. Adole
Keyword(s):  
Experimental Data ◽  
Dielectric Constant ◽  
Apparent Molar Volumes ◽  
Strong Electrolyte ◽  
Aqueous Methanol ◽  
Molar Volumes ◽  
Solvent Interactions ◽  
Viscosity Coefficients ◽  
Physicochemical Processes ◽  
Increase With Increase

The densities and viscosities of electrolytes are essential to understand many physicochemical processes that are taking place in the solution. In the present research, the densities and viscosities of lithium halides, LiX (X = Cl, Br, I ) and KCl in (0, 20, 40, 50, 60, 80 and 100) mass % of methanol + water at 313.15K were calculated employing experimental densities (ρ), the apparent molar volumes( ϕv) and limiting apparent molar volumes (0v) of the electrolytes. The (0v) of electrolyte offer insights into solute-solution interactions. In terms of the Jones-Dole equation for strong electrolyte solution, the experimental data of viscosity were explored. Viscosity coefficients A and B have been interpreted and discussed. The B-coefficient values in these systems increase with increase of methanol in the solvents mixtures. This implied that when the dielectric constant of the solvent decreases, so do the solvent-solvent interactions in these systems.

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