Modelling of ‘sub-atomic’ contrast resulting from back-bonding on Si(111)-7×7

It has recently been shown that ‘sub-atomic’ contrast can be observed during NC-AFM imaging of the Si(111)-7×7 substrate with a passivated tip, resulting in triangular shaped atoms [Sweetman et al. Nano Lett. 2014, 14, 2265]. The symmetry of the features, and the well-established nature of the dangling bond structure of the silicon adatom means that in this instance the contrast cannot arise from the orbital structure of the atoms, and it was suggested by simple symmetry arguments that the contrast could only arise from the backbonding symmetry of the surface adatoms. However, no modelling of the system has been performed in order to understand the precise origin of the contrast. In this paper we provide a detailed explanation for ‘sub-atomic’ contrast observed on Si(111)-7×7 using a simple model based on Lennard-Jones potentials, coupled with a flexible tip, as proposed by Hapala et al. [Phys. Rev. B 2014, 90, 085421] in the context of interpreting sub-molecular contrast. Our results show a striking similarity to experimental results, and demonstrate how ‘sub-atomic’ contrast can arise from a flexible tip exploring an asymmetric potential created due to the positioning of the surrounding surface atoms.

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Improved Electrical and Transport Characteristics of Amorphous Silicon by Enriching with Microcrystalline Silicon

MRS Proceedings ◽

10.1557/proc-336-377 ◽

1994 ◽

Vol 336 ◽

Cited By ~ 7

Author(s):

A. Mireshghi ◽

W.S. Hong ◽

J. Drewery ◽

T. Jing ◽

S.N. Kaplan ◽

...

Keyword(s):

Simple Model ◽

Amorphous Silicon ◽

Radiation Detection ◽

Experimental Results ◽

Electrical Characteristics ◽

Dangling Bond ◽

Microcrystalline Silicon ◽

Bond Density

ABSTRACTWe have deposited n-i-p diodes with microcrystalline intrinsic layers for radiation detection applications. The diodes show interesting electrical characteristics which have not been reported before. From TOF Measurement for our best samples we obtained μe values which are about 3 times larger than our standard a-Si:H. for μτ values approximately a factor of 2 improvement was observed. The N*D values derived from hole-onset measurements show lower ionized dangling bond density than normal a-Si:H Material. We have proposed a simple model which can very well explain the experimental results.

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Radiofrequency Heating of Rubber and Carbon Black Mixes

Rubber Chemistry and Technology ◽

10.5254/1.3539188 ◽

1968 ◽

Vol 41 (5) ◽

pp. 1219-1230

Author(s):

N. H. Langton

Keyword(s):

Simple Model ◽

Carbon Black ◽

Breakdown Voltage ◽

Random Distribution ◽

Reliable Data ◽

Experimental Results ◽

Dielectric Heating ◽

Radiofrequency Heating ◽

Uniform Array

Abstract In conclusion, the simple model of a uniform array of spherical conducting particles of negligible size, when modified for a random distribution, enables predictions as to the maximum permissible loading of carbon black in a rubber/black mix that can be heated by dielectric heating without breakdown. The theory agrees qualitatively with the results of Gehman's theory of random filler dispersions. It is not possible to compare values given by the theory with experimental results, because there is no reliable data giving breakdown voltage figures for rubber/black mixes of known dispersion. However predictions given by the theory agree qualitatively with experiments.

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The dependence of the sputtering ratio of polycrystalline metals on the angle of ion incidence on the target

Canadian Journal of Physics ◽

10.1139/p68-096 ◽

1968 ◽

Vol 46 (6) ◽

pp. 779-782 ◽

Cited By ~ 16

Author(s):

I. N. Evdokimov ◽

V. A. Molchanov

Keyword(s):

Simple Model ◽

Beam Energy ◽

Ion Beam ◽

Target Surface ◽

Close Packing ◽

Experimental Results ◽

Polycrystalline Metals

The sputtering ratio of polycrystalline metals as well as the amount of ion beam energy reflected from the target surface showed angular behavior which was not monotonic at large angles of incidence. The simple model which takes into account "close-packing" at the target surface and, consequently, more or less ordered shadowing of the surface atoms seems to describe the experimental results qualitatively.

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ANHARMONIC CONTRIBUTIONS TO THE BULK MODULUS AND CHARACTERISTIC TEMPERATURES OF NEON AND ARGON AT T = 0 °K

Canadian Journal of Physics ◽

10.1139/p67-247 ◽

1967 ◽

Vol 45 (9) ◽

pp. 2995-2997 ◽

Cited By ~ 4

Author(s):

J. S. Brown ◽

G. K. Horton

Keyword(s):

Bulk Modulus ◽

Excellent Agreement ◽

Characteristic Temperature ◽

Experimental Results ◽

Debye Characteristic Temperature ◽

Characteristic Temperatures ◽

Lennard Jones ◽

Anharmonic Potential ◽

Potential Parameters

Anharmonic contributions to the bulk moduli of Ne and Ar are calculated for Lennard-Jones (m–6) potentials and compared with the experimental results at T = 0 °K. We consider direct anharmonic contributions to the bulk moduli and the anharmonic contributions via the use of Brown's (1966) anharmonic potential parameters. Excellent agreement is found with the experimental results of Peterson, Batchelder, and Simmons (1966) and Batchelder, Losee, and Simmons (1967).We also study the effect of the anharmonic parameters on the Debye characteristic temperature obtained from Cν. Improved agreement with the experimental results is found.

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Creating Superposition: The Beam Splitter

Quantum Computing for the Quantum Curious ◽

10.1007/978-3-030-61601-4_3 ◽

2021 ◽

pp. 17-28

Author(s):

Ciaran Hughes ◽

Joshua Isaacson ◽

Anastasia Perry ◽

Ranbel F. Sun ◽

Jessica Turner

Keyword(s):

Simple Model ◽

Experimental Evidence ◽

Nature Of Science ◽

Beam Splitter ◽

Quantum Computer ◽

Experimental Results ◽

Zehnder Interferometer ◽

Quantum Superposition ◽

Quantum Particles ◽

True Quantum

AbstractNow that we have explored qubits and the phenomenon of superposition, we can ask the question: how do we know that superposition actually happens? is the evidence that shows that a quantum particle really does exist in two different locations at this same time while in a quantum superposition? The nature of science means that experiments are constantly updating previous results, so are there other interpretations of the experimental results that can explain the data without the need for superposition? In this chapter we’ll explore the experimental evidence interpretations other than quantum superposition. Further, while a flipping coin is a simple model of a qubit, it is not very useful for building a quantum computer because it does not exhibit all of the properties of a true quantum superposition. For example, we cannot manipulate the superposition amplitudes. In this chapter, we will study some real physical examples of quantum particles in a superposition containing two states. These examples include a photon in a beam splitter and the Mach–Zehnder interferometer.

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Delta-mu XANES reveals the electronic structure of the adsorption of propene on gold nanoparticles

RSC Advances ◽

10.1039/c3ra47209d ◽

2014 ◽

Vol 4 (24) ◽

pp. 12293-12297 ◽

Cited By ~ 3

Author(s):

Ana Mijovilovich

Keyword(s):

Gold Nanoparticles ◽

Electronic Structure ◽

Au Nanoparticles ◽

Experimental Results ◽

Back Bonding ◽

Small Nanoparticles

Experimental delta-mu spectra for the H oxidated and the propene co-fed Au nanoparticles were reproduced with XANES simulations with FEFF9. The results support that the propene has pi back-bonding to the Au with binding at defects or steps or in very small nanoparticles. Cationic, or even better, the neutrally charged Au nanoparticles, reproduce the experimental results of the propene co-fed catalyst found in the literature.

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Photoconductivity of semi-insulating gallium arsenide in the presence of a magnetic field

Canadian Journal of Physics ◽

10.1139/p69-341 ◽

1969 ◽

Vol 47 (24) ◽

pp. 2789-2796 ◽

Cited By ~ 11

Author(s):

H. Milner-Brown ◽

E. Fortin

Keyword(s):

Magnetic Field ◽

Gallium Arsenide ◽

Simple Model ◽

Surface Treatment ◽

Sample Surface ◽

Sample Thickness ◽

Experimental Results ◽

Theoretical Predictions ◽

Temperature Surface

The effect of a magnetic field on the photoconductivity of GaAs has been investigated at 300 °K and 90 °K. The field deflects the photocarriers towards the surface or the volume of the sample, resulting in a decrease or an increase of the photocurrent. The effect is attributed to lifetime inhomogeneities across the sample thickness and has been studied as a function of temperature, surface treatment of the sample, and wavelength of excitation. The results can be expressed as the ratio R = ip+/ip−, where ip+ and ip− are the photocurrents when the carriers are deflected away or towards the sample surface respectively. For a sample mechanically polished, R = 10 at 300 °K and R = 40 at 90 °K while for a chemically polished sample R = 3.5 at 300 °K and R = 10 at 90 °K for B = 2.2 Wb/m2, V = 400 V, and λ excitation = 7500 Å. Independent measurements of the carrier mobilities and of their surface and bulk lifetimes have been performed to allow a direct comparison between experimental results and theoretical predictions based on a simple model.

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A breakup of a droplet falling into a miscible solution

10.5194/egusphere-egu2020-1912 ◽

2020 ◽

Author(s):

Michiko shimokawa ◽

Hidetsugu Sakaguchi

Keyword(s):

Simple Model ◽

Probability Distribution ◽

Vortex Ring ◽

Mode Selection ◽

Experimental Results ◽

Mode Number ◽

Low Density ◽

Experimental Conditions ◽

Average Value ◽

Rayleigh Taylor Instability

When a droplet with a relatively high density falls into a miscible solution with a relatively low density, the droplet breaks up spontaneously. We investigated the number m of breakup in experiments with several density differences &#916;&#961; between two solutions, viscosities &#956;, and droplet radii r. The mode number m has a distribution even under the same experimental conditions. We propose a simple model of mode selection based on the linear Rayleigh-Taylor instability and the growing radius of a vortex ring deformed from the droplet. The model provides the probability distribution P(m) and a relationship between the nondimensional parameter G &#8733; &#916;&#961;gr3/&#956;2 and the average value of m, which are consistent with experimental results.

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Energy Comparison Between Trot, Bound, and Gallop Using a Simple Model

Journal of Biomechanical Engineering ◽

10.1115/1.2794209 ◽

1995 ◽

Vol 117 (4) ◽

pp. 466-473 ◽

Cited By ~ 42

Author(s):

P. Nanua ◽

K. J. Waldron

Keyword(s):

Simple Model ◽

Periodic Solutions ◽

Energy Levels ◽

The Body ◽

Experimental Results ◽

Gait Transition ◽

Transition Speed ◽

Quadruped Trot

In this paper, the dynamics of quadruped trot, gallop, and bound will be examined using a simple model for the quadruped. The body of the quadruped is modeled as a uniform bar and the legs are modeled by massless springs. It will be shown that symmetry can be used to study the locomotion of this system. Using symmetry, a technique will be developed to obtain periodic solutions for each of the gaits of the quadruped model. These periodic solutions will be computed at various speeds. The energy levels will be compared for each of the gaits. The exchange of energy between its different forms will be shown for different gaits. It will be shown that even without body flexibility, there are significant savings in energy due to gait transition from trot to gallop. The energy levels will be used to predict the trot-gallop transition speed. These results will be compared with the experimental results for horses and dogs.

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Modal Noise. The Influence of Modal Noise on a Digital 1.3 μm Optical Transmission System

Journal of Optical Communications ◽

10.1515/joc-1984-0107 ◽

1984 ◽

Vol 5 (1) ◽

Author(s):

W. Koester ◽

O. Strobel

Keyword(s):

Simple Model ◽

Optical Transmission ◽

Optical Feedback ◽

Transmission System ◽

Experimental Results ◽

New Method ◽

Optical Elements ◽

Mode Selectivity ◽

Optical Transmission Systems ◽

Modal Noise

SummaryThe performance increase of optical transmission systems creates new problems like optical feedback and modal noise. It is very important to overcome these problems especially in systems composed by a lot of single optical elements. In this paper we describe a new method to determine the degree of mode selectivity produced by these devices. A simple model for modal noise description together with experimental results are presented.

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