Enhanced Photoyield with Decreasing Film Thickness on Metal-Semiconductor Structures

1996 ◽  
Vol 448 ◽  
Author(s):  
V. Hoffmann ◽  
M. Brauer ◽  
M. Schmidt
Keyword(s):  
Quantum Yield ◽  
Film Thickness ◽  
Layer Thickness ◽  
Experimental Results ◽  
Experimental Result ◽  
Model Calculations ◽  
Hot Carrier ◽  
Semiconductor Structures ◽  
Carrier Scattering ◽  
Good Agreement

AbstractExperimental results of the internal quantum yield Yi associated with the internal photoemission on Au/n-Si structures are presented. The samples were prepared on Si(100) and Si(111) substrates with photoemitter layer thicknesses ranging from 5 nm to 50 nm. The Yi was measured at temperatures between 165 K and 300 K with the photoexciting energy varying from 0.72 eV to 1.07 eV. It was found that the Yi increases with decreasing Au layer thickness with a strong enhancement (40 times) in regard to the conventional Fowler theory. This experimental result is in good agreement with model calculations taking account of hot carrier scattering in the photoemitter layer. Barrier energies are larger than deduced from the Fowler plot.

Hydration of the potassium ion in the gas phase: enthalpies and entropies of hydration reactions

1969 ◽  
Vol 47 (14) ◽  
pp. 2619-2627 ◽  
Author(s):  
S. K. Searles ◽  
P. Kebarle
Keyword(s):  
Water Vapor ◽  
Gas Phase ◽  
Thermionic Emission ◽  
Reaction Chamber ◽  
Experimental Result ◽  
Electrostatic Model ◽  
Model Calculations ◽  
Thermodynamic Constants ◽  
Electrostatic Calculations ◽  
Good Agreement

The thermodynamic constants ΔH0n−1,n, ΔG0n−1,n, and ΔS0n−1,n for the reaction [n − 1, n]: K+(H2O)n−1 + H2O = K+(H2O)n proceeding in the gas phase were measured for n = 1 to n = 6. The equilibria were studied in a reaction chamber containing water vapor at pressures from 0.3 to 6 Torr and at temperatures from −11 to 390 °C. The potassium ions were produced by thermionic emission in a filament chamber and then were equilibrated with the water vapor in the reaction chamber. The relative ionic concentrations were detected with a mass spectrometer. The experimental ΔH0n−1,n values are compared with potential energy differences for the reactions [n − 1, n] based on simple electrostatic model calculations. The electrostatic calculations produce values in fair agreement with the experimental results. The ΔS00,1 calculated on basis of statistical mechanics and energies obtained with the electrostatic model is in very good agreement with the experimental result.

Photoalpha Reactions in the Region Z = 22 – 30

1972 ◽  
Vol 50 (13) ◽  
pp. 1554-1567 ◽  
Author(s):  
N. A. Keller ◽  
D. B. McConnell
Keyword(s):  
Statistical Model ◽  
Experimental Results ◽  
Angular Distributions ◽  
Model Calculations ◽  
Good Agreement

The yields and angular distributions of photoalphas from seven elements in the region Z = 22–30 were investigated experimentally. Strong anisotropies in the angular distributions from the even–even nuclei were observed. Improved statistical model calculations using the known spins and parities of the low lying levels of the even–even daughters give good agreement with the experimental results.

Stribeck Curve for Starved Line Contacts

2006 ◽  
Vol 129 (1) ◽  
pp. 181-187 ◽  
Author(s):  
I. C. Faraon ◽  
D. J. Schipper
Keyword(s):  
Film Thickness ◽  
Layer Thickness ◽  
Boundary Lubrication ◽  
Numerical Data ◽  
Contact Model ◽  
Stribeck Curve ◽  
Lubrication Regime ◽  
Straight Line ◽  
Line Contacts ◽  
Good Agreement

This paper discusses a mixed lubrication model in order to predict the Stribeck curve for starved lubricated line contacts. This model is based on a combination of the contact model of Greenwood and Williamson and the elastohydrodynamic (EHL) film thickness for starved line contacts. The starved solution to be implemented in the EHL component is obtained by using numerical data of Wolveridge, who computed the starved film thickness for smooth line contacts. Calculations are presented for different oil supply layer thickness over roughness values (hoil∕σs). For values of the oil layer thickness over roughness ratio larger than approximately 6, the Stribeck curve and separation between the rough surfaces do not change compared to the fully flooded situation. If the oil layer thickness over roughness ratio is in the range of 6 down to 0.7, friction starts to increase and the film thickness decreases. When the oil layer thickness over roughness ratio is less than approximately 0.7, the Stribeck curve tends to transform into a straight line and separation stays at the same value as in the boundary lubrication regime. Comparison between measurements and calculations is made and a good agreement is found.

Simulation of Fracture Behavior of Elastomer Modified Polypropylene Based on Elastoviscoplastic Constitutive Equation With Craze and Tensile Softening Law

2005 ◽  
Author(s):  
Hiroyuki Mae
Keyword(s):  
Constitutive Equation ◽  
Crack Propagation ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Experimental Results ◽  
Experimental Result ◽  
Load Displacement ◽  
Macroscopic Crack ◽  
Tensile Softening ◽  
Good Agreement

The strong strain-rate dependence, neck propagation and craze evolution characterize the large plastic deformation and fracture behavior of polymer. In the latest study, Kobayashi, Tomii and Shizawa suggested the elastoviscoplastic constitutive equation based on craze evolution and annihilation and then applied it to the plane strain issue of polymer. In the previous study, the author applied their suggested elastoviscoplastic constitutive equation with craze effect to the three dimensional shell issue and then showed that the load displacement history was in good agreement with the experimental result including only microscopic crack such as craze. For the future industrial applications, the macroscopic crack had to be taken into account. For instance, an airbag deployment simulation needed the macroscopic crack prediction. Thus, the main objective of this study was to propose the tensile softening equation and then add it to the elastoviscoplastic constitutive equation with craze effect so that the load displacement history could be roughly simulated during the macroscopic crack propagation. The tested material in this study was the elastomer blended polypropylene used in the interior and exterior of automobiles. First, the material properties were obtained based on the tensile test results at wide range of strain rates: 10−4 – 102 (1/sec). Next, the fast compact tension test was conducted and then the tensile softening parameters were fixed. Then, the fast bending test and the dart impact test were carried out in order to obtain the load displacement history and also observe the macroscopic crack propagation at high strain rate. Finally, the fracture behavior was simulated and then compared with the experimental results. It was shown that the predictions of the constitutive equation with the proposed tensile softening equation were in good agreement with the experimental results.

scholarly journals An Independent-Flow-Field Model for a SDOF Nonlinear Structural System–Part II: Analysis of Complex Responses

2005 ◽  
Vol 128 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Huan Lin ◽  
Solomon C. S. Yim
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Periodic Wave ◽  
Experimental Results ◽  
Experimental Result ◽  
Structural System ◽  
Frequency Domains ◽  
Wave Heights ◽  
System Part ◽  
Good Agreement

Complex responses observed in an experimental, nonlinear, moored structural system subjected to nearly periodic wave excitations are examined and compared to the simulations of a newly proposed independent-flow-field (IFF) model in this paper. Variations in wave heights are approximated by additive random perturbations to the dominant periodic component. Simulations show good agreement with the experimental results in both time and frequency domains. Noise effects on the experimental results, including bridging and transition phenomena, are investigated and interpreted by comparing to the simulations of its deterministic counterpart. Possible causes of a chaoticlike experimental result as previously observed are also inferred.

scholarly journals An Independent-Flow-Field Model for a SDOF Nonlinear Structural System: Part II — Analysis of Complex Responses

2003 ◽  
Author(s):  
Huan Lin ◽  
Solomon C. S. Yim
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Periodic Wave ◽  
Experimental Results ◽  
Experimental Result ◽  
Structural System ◽  
Frequency Domains ◽  
Wave Heights ◽  
System Part ◽  
Good Agreement

Complex responses observed in an experimental, nonlinear, moored structural system subjected to nearly periodic wave excitations are examined and compared with the simulations of a newly proposed independent-flow-field (IFF) model in this paper. Variations in wave heights are approximated by additive random perturbations to the dominant periodic component. Simulations show good agreement with the experimental results in both time and frequency domains. Noise effects on the experimental results including bridging and transition phenomena are investigated and interpreted by comparing with the simulations of its deterministic counterpart. Possible causes of a chaotic-like experimental result as previously observed are also inferred.

Delamination Evaluation Approach for Bimaterial Structure Considering Interfacial Layer

2007 ◽  
Author(s):  
Qiang Yu ◽  
Tadahiro Shibutani ◽  
Masaki Shiratori ◽  
Tomio Matsuzaki ◽  
Tsubasa Matsumoto
Keyword(s):  
Interfacial Layer ◽  
Interfacial Strength ◽  
Interfacial Fracture ◽  
Experimental Results ◽  
Interfacial Structure ◽  
Experimental Result ◽  
Bonding Layer ◽  
Mechanical Fracture ◽  
Uf Resin ◽  
Good Agreement

In recent years, interfacial fracture is one of the most important issues in the assessment of reliability of electronics packaging. In particular, underfill (UF) resin is used to prevent thermal fatigue of solder joints in flip chip packaging. Interfacial fracture between components/substrates and UF resin also affects the reliability of electronic devices. In general, the interfacial strength can be evaluated with the concept of interfacial fracture mechanics. However, as new materials and new processes using in the devices increase, it becomes clear that the fracture concept is difficult to evaluate the interfacial strength quantitatively. Many researches assumed that the interface is bonded perfectly. However, the interface has the micro-scale structure and the bonding may be imperfect. Specially interfaces of the resin have complicated structure. In this study, an alternative approach for evaluating the mechanical fracture of the interfacial structure of resin in electronic components was proposed. The basic mechanical behavior of the new interfacial model with imperfect bonding layer was examined by using finite element analysis. The stress field around the interfacial layer depends not only on the properties of interfacial layer but also on the micro structure of the interfacial layer. In addition, based on the experimental result of the tensile and the shearing test from the reference, the mechanical models of the interfacial structure were constructed. The conditions of delamination were examined by using FEA Furthermore, the new model and approach was confirmed quantitatively. It was found that the basic properties of the interfacial layer can be tuned to the proper values by two different delamination tests, and the new approach could show good agreement with the experimental results from the initial delaminaiton to the instability fracture process qualitatively. The simulation results were in good agreement with the experimental results.

scholarly journals Isomer ratios for the 88Sr(p,xn) and 88Sr(p,p3n) reactions

1967 ◽  
Vol 45 (22) ◽  
pp. 2711-2721 ◽  
Author(s):  
D. R. Sachdev ◽  
L. Yaffe
Keyword(s):  
Statistical Model ◽  
Spin Density ◽  
Cross Section ◽  
Experimental Results ◽  
Density Parameter ◽  
Model Calculations ◽  
Experimental Values ◽  
Parameter Values ◽  
Good Agreement

Isomeric cross-section ratios for nuclides formed from (p,2n), (p,3n), (p,4n), and (p,p3n) reactions on 88Sr are presented. The experimental results for the 88Sr(p,2n)87Ym,g reaction are compared with statistical-model calculations wherein spin-density parameter values were obtained from various theoretical formalisms. The parameters required to match the calculated and experimental values are in good agreement with those obtained by Vandenbosch et al.

Measurement of Film Thickness for Continuous Fluid Flow Within a Spinning Cone

2014 ◽  
Author(s):  
Digby D. Symons ◽  
Arnaud F. M. Bizard
Keyword(s):  
Fluid Flow ◽  
Angular Velocity ◽  
Film Thickness ◽  
Industrial Process ◽  
Vertical Axis ◽  
Experimental Results ◽  
Analytical Theory ◽  
Thin Film Flow ◽  
Thickness Measurements ◽  
Good Agreement

This paper reports experimental measurements of film thickness for continuous fluid flow within a spinning cone. The results are compared to analytical theory for thin film flow and found to be in good agreement. Spinning cones are used in various industrial process machines, including spinning cone distillation columns, centrifugal film evaporators and continuous centrifugal filters. In each case a fluid is fed continuously into the centre of a conical vessel which spins about a vertical axis with the cone apex pointing downwards. The fluid acquires the angular velocity of the cone and migrates up the internal wall of the cone under centrifugal force. Knowledge of the film thickness and flow velocity is often important in order to understand other performance parameters of the process such as evaporation or filtration rates. This paper aims to aid the design of new process machines by providing a mathematical model for film thickness that is validated by experimental results. Experiments have been conducted in which the angle of cone, angular velocity and input flow rate were all varied. Film thickness measurements were obtained via a novel optical method based on photographing the displacement of a projected grid on the surface of the flow within the cone. The method has the advantages of not disturbing the flow in any way and can provide thickness measurements over the whole cone depth. Measurements are also made insensitive to any transients by use of relatively long photographic exposures. Measurements are compared to analytical theory for axisymmetric, steady state, free-surface laminar flow of a Newtonian fluid in a spinning cone. The theory assumes the flow is thin but takes account of gravity. The theoretical model is found to be in good agreement with the experimental results.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

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