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

1969 ◽  
Vol 47 (24) ◽  
pp. 2789-2796 ◽  
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.

Effect of Textures on the Nanomechanical Properties of Nanocrystalline Fe-50%Ni Foil

2006 ◽  
Vol 15-17 ◽  
pp. 923-928
Author(s):  
Jong Kweon Kim ◽  
Shi Hoon Choi ◽  
Yong Bum Park
Keyword(s):  
Elastic Modulus ◽  
Sample Thickness ◽  
Experimental Results ◽  
Nanoindentation Test ◽  
Specimen Thickness ◽  
Strong Decrease ◽  
Nanomechanical Properties ◽  
Texture Change ◽  
Theoretical Predictions ◽  
Good Agreement

The textures and nanomechanical properties of nanocrystalline Fe-50wt%Ni foil fabricated by using an electroforming method were investigated. The as-deposited texture was characterized by major <100>//ND and minor <111>//ND fibre components. Annealing of the as-deposited specimen resulted in the texture change that the <111>//ND fibre texture developed strongly with decreasing <100>//ND intensity. The elastic modulus and hardness were investigated by nanoindentation test, and these experimental results were compared with the theoretical predictions based on an elastic self-consistent (ESC) polycrystal model. Annealing led to an increase in the elastic modulus and a strong decrease in the hardness. At the low ratio of indentation depth to the specimen thickness, the theoretical predictions of the elastic modulus in the sample thickness direction showed a good agreement with experimental results.

The Model for Calculation the Hall Effect Parameter

2004 ◽  
Vol 9 (2) ◽  
pp. 129-138
Author(s):  
J. Kleiza ◽  
V. Kleiza
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Mapping Method ◽  
Sample Thickness ◽  
System Of Nonlinear Equations ◽  
Specific Resistivity ◽  
Conformal Mapping Method ◽  
Effect Parameter ◽  
The Magnetic Field

A method for calculating the values of specific resistivity ρ as well as the product µHB of the Hall mobility and magnetic induction on a conductive sample of an arbitrary geometric configuration with two arbitrary fitted current electrodes of nonzero length and has been proposed an grounded. During the experiment, under the constant value U of voltage and in the absence of the magnetic field effect (B = 0) on the sample, the current intensities I(0), IE(0) are measured as well as the mentioned parameters under the effect of magnetic fields B1, B2 (B1 ≠ B2), i.e.: IE(β(i)), I(β(i)), i = 1, 2. It has been proved that under the constant difference of potentials U and sample thickness d, the parameters I(0), IE(0) and IE(β(i)), I(β(i)), i = 1, 2 uniquely determines the values of the product µHB and specific resistivity ρ of the sample. Basing on the conformal mapping method and Hall’s tensor properties, a relation (a system of nonlinear equations) between the above mentioned quantities has been found.

scholarly journals Early-Age Tensile Bond Characteristics of Epoxy Coatings for Underwater Applications

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 757 ◽  
Author(s):  
Kim ◽  
Hong ◽  
Han ◽  
Kim
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Epoxy Resin ◽  
Coating Thickness ◽  
Experimental Results ◽  
Early Age ◽  
Curing Time ◽  
Bond Performance ◽  
Coating Type ◽  
Bond Characteristics

In this study, coating equipment for the effective underwater repair of submerged structures was developed. The tensile bond characteristics of selected epoxy resin coatings were investigated by coating the surface of a specimen using each of the four types of equipment. Using the experimental results, the tensile bond strength and the coating thickness were analyzed according to the type of equipment, coating, and curing time. The results show that the type of coating equipment used had the greatest effect on the measured bond strength and coating thickness of the selected coatings. However, the effect of coating type and curing time on the bond strength and the thickness was observed to be insignificant. Compared with the developed equipment, the surface treatment of the coating was observed to be more effective when using the pre-existing equipment, and thus the bond performance of the coating was improved compared to using the pre-existing equipment. Based on the experimental results, improvements and needs involving the equipment for further research were discussed.

scholarly journals Quantitative Experimental and Theoretical Investigations on the Interaction of Shock Waves with Magnetic Fields

1969 ◽  
Vol 24 (10) ◽  
pp. 1449-1457
Author(s):  
H. Klingenberg ◽  
F. Sardei ◽  
W. Zimmermann
Keyword(s):  
Magnetic Fields ◽  
Shock Waves ◽  
Physical Model ◽  
Spectroscopic Method ◽  
Experimental Results ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Theoretical Investigations ◽  
Theoretical Predictions ◽  
Interaction Of Shock Waves

Abstract In continuation of the work on interaction between shock waves and magnetic fields 1,2 the experiments reported here measured the atomic and electron densities in the interaction region by means of an interferometric and a spectroscopic method. The transient atomic density was also calculated using a one-dimensional theory based on the work of Johnson3 , but modified to give an improved physical model. The experimental results were compared with the theoretical predictions.

scholarly journals Experimental study of the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions at the Mainz Microtron

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
C. S. Akondi ◽  
K. Bantawa ◽  
D. M. Manley ◽  
S. Abt ◽  
P. Achenbach ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cross Sections ◽  
Differential Cross ◽  
Legendre Polynomials ◽  
Neutral Kaon ◽  
Experimental Results ◽  
Differential Cross Sections ◽  
Theoretical Predictions ◽  
Photoproduction Reactions ◽  
Insight Into

Abstract.This work measured $ \mathrm{d}\sigma/\mathrm{d}\Omega$dσ/dΩ for neutral kaon photoproduction reactions from threshold up to a c.m. energy of 1855MeV, focussing specifically on the $ \gamma p\rightarrow K^0\Sigma^+$γp→K0Σ+, $ \gamma n\rightarrow K^0\Lambda$γn→K0Λ, and $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 reactions. Our results for $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 are the first-ever measurements for that reaction. These data will provide insight into the properties of $ N^{\ast}$N* resonances and, in particular, will lead to an improved knowledge about those states that couple only weakly to the $ \pi N$πN channel. Integrated cross sections were extracted by fitting the differential cross sections for each reaction as a series of Legendre polynomials and our results are compared with prior experimental results and theoretical predictions.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

Accommodation and Convergence in the Human Eye

1969 ◽  
Vol 2 (3) ◽  
pp. T29-T33 ◽  
Author(s):  
F. M. Toates
Keyword(s):  
Control Systems ◽  
Control Model ◽  
Monocular Vision ◽  
Experimental Results ◽  
After Effects ◽  
Human Eye ◽  
Theoretical Predictions ◽  
Accommodative Convergence ◽  
Effect Of Age

The control systems of accommodation and convergence in the human eye are theoretically examined, together with their interactions which represent accommodative convergence and convergence induced accommodation. A control model is proposed in order to help to understand the system, and it is used to make predictions concerning accommodation and convergence placed in conflict, monocular vision, fusional after-effects and the effect of age and drugs on accommodation and accommodative convergence. In each case the theoretical predictions are compared with established experimental results.

ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Simple Model ◽  
Critical Frequency ◽  
Optical Methods ◽  
Phase Lag ◽  
Rotating Magnetic Fields ◽  
Mr Fluids ◽  
Small Angle Light Scattering ◽  
The Magnetic Field

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.

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