scholarly journals Formation of metal/semiconductor Cu–Si composite nanostructures

2019 ◽  
Vol 10 ◽  
pp. 2497-2504
Author(s):  
Natalya V Yumozhapova ◽  
Andrey V Nomoev ◽  
Vyacheslav V Syzrantsev ◽  
Erzhena Ch Khartaeva
Keyword(s):  
Cooling Rate ◽  
Short Distance ◽  
Potential Method ◽  
Diameter Distribution ◽  
Composite Nanostructures ◽  
Si Nanoparticles ◽  
Particle Potential ◽  
Dynamics Modelling ◽  
Simulation Results ◽  
The Many

Molecular dynamics modelling of the formation of copper and silicon composite nanostructures was carried out by using the many-particle potential method. The dependences of the internal structure on the cooling rate and the ratio of elements were investigated. The possibility of the formation of the Cu–Si nanoparticles from both a homogeneous alloy and two initial drops at short distance were shown. A comparative analysis showed that the diameter distribution of copper and silicon atoms in experimental particles coincides with the simulation results with silicon content of 50 atom %. Additionally, an estimation of the effective experimental cooling rate was made.

Some observations on fitting assumed diameter distributions to horizontal point sampling data

2000 ◽  
Vol 30 (4) ◽  
pp. 521-533 ◽  
Author(s):  
Jeffrey H Gove
Keyword(s):  
Diameter Distribution ◽  
Parameter Estimates ◽  
Sample Point ◽  
Underlying Distribution ◽  
Weighted Distribution ◽  
Reliable Parameter ◽  
Simulation Results ◽  
Larger Sample ◽  
Horizontal Point Sampling ◽  
Diameter Distributions

This paper revisits the link between assumed diameter distributions arising from horizontal point samples and their unbiased stand-based representation through weighted distribution theory. Examples are presented, which show that the assumption of a common shared parameter set between these two distributional forms, while theoretically valid, may not be reasonable in many operational cases. Simulation results are presented, which relate the conformity (or lack thereof) in these estimates to sampling intensity per point and the underlying shape of the population diameter distribution from which the sample point was drawn. In general, larger sample sizes per point are required to yield reliable parameter estimates than are generally taken for inventory purposes. In addition, a complimentary finding suggests that the more positively skewed the underlying distribution, the more trees per point are required for good parameter estimates.

Optimization of built-part distortion in laser powder bed fusion processing of Inconel 718

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
You-Cheng Chang ◽  
Hong-Chuong Tran ◽  
Yu-Lung Lo
Keyword(s):  
Cooling Rate ◽  
Cantilever Beam ◽  
Laser Power ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Powder Bed Fusion ◽  
Simulation Framework ◽  
Content Type ◽  
Powder Bed ◽  
Simulation Results

Purpose Laser powder bed fusion (LPBF) provides the means to produce unique components with almost no restriction on geometry in an extremely short time. However, the high-temperature gradient and high cooling rate produced during the fabrication process result in residual stress, which may prompt part warpage, cracks or even baseplate separation. Accordingly, an appropriate selection of the LPBF processing parameters is essential to ensure the quality of the built part. This study, thus, aims to develop an integrated simulation framework consisting of a single-track heat transfer model and a modified inherent shrinkage method model for predicting the curvature of an Inconel 718 cantilever beam produced using the LPBF process. Design/methodology/approach The simulation results for the curvature of the cantilever beam are calibrated via a comparison with the experimental observations. It is shown that the calibration factor required to drive the simulation results toward the experimental measurements has the same value for all settings of the laser power and scanning speed. Representative combinations of the laser power and scanning speed are, thus, chosen using the circle packing design method and supplied as inputs to the validated simulation framework to predict the corresponding cantilever beam curvature and density. The simulation results are then used to train artificial neural network models to predict the curvature and solid cooling rate of the cantilever beam for any combination of the laser power and scanning speed within the input design space. The resulting processing maps are screened in accordance with three quality criteria, namely, the part density, the radius of curvature and the solid cooling rate, to determine the optimal processing parameters for the LPBF process. Findings It is shown that the parameters lying within the optimal region of the processing map reduce the curvature of the cantilever beam by 17.9% and improve the density by as much as 99.97%. Originality/value The present study proposes a computational framework, which could find the parameters that not only yield the lowest distortion but also produce fully dense components in the LPBF process.

Pts-Oi Complex Formation in Platinum Diffused Silicon

2005 ◽  
Vol 864 ◽  
Author(s):  
Wilfried Vervisch ◽  
Laurent Ventura ◽  
Bernard Pichaud ◽  
Gérard Ducreux ◽  
André Lhorte
Keyword(s):  
Thermal Treatment ◽  
Complex Formation ◽  
Cooling Rate ◽  
Point Defects ◽  
Diffusion Processes ◽  
Silicon Wafers ◽  
Doping Behaviour ◽  
Simulation Results ◽  
Dopant Atoms ◽  
P Type

AbstractWhen platinum is diffused at temperatures higher than 900°C in Cz or FZ low doped n-type silicon samples, which are then cooled slowly in the range [1-10]°C/min, a p-type doping leading to the formation of a pn junction can be observed by spreading resistance measurement. The lower the cooling rate, the deeper the junction is. This junction disappears after a second thermal treatment finishing with a quenching step. A platinum related complex formation is considered to explain this reversible doping behaviour. Different possible interactions between platinum and other impurities such as dopant atoms, intrinsic point defects, and common residual impurities (C, Oi, transition metallic atoms) are studied here. Experimental results from Pt diffusion processes in different qualities of silicon wafers, and simulation results, lead to the conclusion that the platinum related p-type doping effect is due to the formation of a Pts-Oi complex.

On Canadian Caverns

The Geologist ◽  
1860 ◽  
Vol 3 (6) ◽  
pp. 213-219
Author(s):  
George D. Gibb
Keyword(s):  
Short Distance ◽  
Main Road ◽  
Ottawa River ◽  
The Road ◽  
Lower Silurian ◽  
Wheeled Vehicle ◽  
Limestone Rock ◽  
The Many ◽  
The Village ◽  
Country People

The greater part of the main road from Carillon to Grenville, a distance of thirteen miles on the northern banks of the Ottawa River, runs over the Calciferous sand rook of the Lower Silurian formation. In many places ihe surface of the rock is exposed, and beyond the village of Chatham, towards Grenville, and even in Chatham, for a short distance, the road consists of the solid limestone rock. As the surface of the rock is more or less rough or uneven, the road is an uncomfortable one to travel over in a wheeled vehicle. On driving over that part of the rock just near Chatham, a tremendous loud rumbling noise is occasioned by the stage, which is not heard, in other situation. This has been attributed to the presence of one or more large caverns situated beneath the road at this place: and, on making inquiry on the spot, I learnt that a prevalent opinion has long been entertained by the country people and many intelligent persons in the to neigbourhood, that a considerable cavern does exist in this part of the country in the place mentioned. On the many occasions that I have driven over this road, the loud rumbling noise has been invariably observed by my fellow travellers as well as by myself. Sotne-day an opening into the cavern may be discovered and the mystery solved. The main road is, elevated and is probably from seventy to ninety feet above the level of the Ottawa River.

Robot force control without dynamic model: theory and experiments

Robotica ◽  
2012 ◽  
Vol 31 (1) ◽  
pp. 149-171 ◽  
Author(s):  
Juan C. Rivera-Dueñas ◽  
Marco A. Arteaga-Pérez
Keyword(s):  
Model Theory ◽  
Contact Surface ◽  
Force Control ◽  
Control Algorithm ◽  
Velocity Measurements ◽  
Unit Quaternion ◽  
End Effector ◽  
Simulation Results ◽  
The Many ◽  
Theory And Experiments

SUMMARYAmong the many challenges to deal with, when a robot is interacting with its environment, friction at the contact surface and/or at the joints is one of the most important to be considered. In this paper we propose a control algorithm for the tracking of position and force (unconstrained orientation case only) of a manipulator end-effector that does not require the robot model for implementation. This characteristic has the advantage of making it capable to compensate friction effects without any previous estimation. Furthermore, no velocity measurements are needed, and the unit quaternion is employed for orientation control. Experimental and simulation results are provided.

Wombats

2009 ◽  
Author(s):  
Barbara Triggs
Keyword(s):  
Short Distance ◽  
Way Of Life ◽  
Full Account ◽  
Practical Advice ◽  
The Many ◽  
Endangered Animals

One of Australia’s most engaging marsupials, the wombat is also one of the most disparaged and least understood. Often depicted as slow, muddle-headed and clumsy, it can, in fact, outpace a human or a dog over a short distance. Wombats are quick to learn and superbly adapted to their burrowing way of life. This book gives a full account of how wombats live and the many hazards they face. Dealing mainly with the bare-nosed wombat, Vombatus ursinus, it also includes information on the southern hairy-nosed wombat, Lasiorhinus latifrons, as well as the northern hairy-nosed wombat, Lasiorhinus krefftii, which is one of the world’s most endangered animals. The book also gives practical advice on rearing orphan wombats. Completely revised, this new edition has over 100 illustrations, including 23 colour plates and drawings by Peter Schouten.

scholarly journals Columns of Ordeal

1921 ◽  
Vol 24 ◽  
pp. 68-77
Author(s):  
F. W. Hasluck
Keyword(s):  
Short Distance ◽  
The South ◽  
The Sixties ◽  
The Many

No self-respecting Cairene dragoman omits to point out to his clients among the curiosities of the mosque of Amr at Fostat two columns near the South door, which are endowed, according to popular superstition, with the miraculous power of discriminating between true Moslems and Unbelievers. Placed at such a short distance apart (some ten inches) that the passage between them can with difficulty be negotiated by a man of average build, the columns none the less allow a true Moslem, however stout, to pass between them, while an Unbeliever, however slim, finds passage impossible. In other words, the space is supernaturally widened if necessary to accommodate the former and contracted to exclude the latter class.The columns actually used for this purpose at Cairo do not seem long to have been associated with the superstition. Visitors to the mosque in the sixties do not mention it, though they refer to the companion marvel of the column miraculously transported from Mecca. The superstition itself, however, is of great antiquity and relatively well documented. The purpose of the rite, a spiritual test, distinguishes it sharply from the many similar ‘passing through’ rituals universally current and generally considered ‘lucky’ acts practised with a view to the healing of disease, etc. Its symbolism, as we shall see, suggests a Christian origin.

Detection and characterization of an optical vortex by the branch point potential method: analytical and simulation results

2015 ◽  
Vol 54 (15) ◽  
pp. 4732 ◽  
Author(s):  
Abolhasan Mobashery ◽  
Morteza Hajimahmoodzadeh ◽  
Hamid Reza Fallah
Keyword(s):  
Branch Point ◽  
Potential Method ◽  
Optical Vortex ◽  
Point Potential ◽  
Simulation Results

Prediction of Microstructure and Mechanical Properties of Plate in Roller Quenching

2011 ◽  
Vol 328-330 ◽  
pp. 462-465
Author(s):  
Chao Wang ◽  
Jia Dong Li ◽  
Guo Yuan ◽  
Zhao Dong Wang ◽  
Guo Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Temperature Field ◽  
Cooling Rate ◽  
Interpolation Method ◽  
Pressure Vessel Steel ◽  
Thickness Direction ◽  
Plate Temperature ◽  
Vessel Steel ◽  
Finite Difference Equations ◽  
Simulation Results

Finite difference equations are used for simulation of plate temperature field in roller quenching, and cooling rate in thickness direction is calculated in this paper. Based on improved Maynier model of steel chemical composition and cooling rate, the microstructure constituents and hardness of 30mm thickness pressure vessel steel 07MnNiMoVDR are predicted and calculated with interpolation method. The experimental verification indicates that the simulation results agree well with the experimental ones.

Effect of Nozzle Layout Parameters on the Controlled Cooling of Flat Steel

2010 ◽  
Vol 145 ◽  
pp. 326-331 ◽  
Author(s):  
Shao Jun Zhang ◽  
Dong Mei Zhu ◽  
Guo Yong Liu
Keyword(s):  
Numerical Simulation ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Cooling Process ◽  
Controlled Cooling ◽  
Cooling Device ◽  
Coupling Field ◽  
Simulation Calculation ◽  
Flat Steel ◽  
Simulation Results

The three dimensional unsteady cooling process of flat steel is simulated by the numerical simulation calculation method of Finite Element Coupling Field. Then, the influential rules, which about layout parameters of the controlled cooling nozzle such as the distance and number of nozzle rows on the cooling effect, are analyzed separately. The results show that the distance of nozzle has a little effect on cooling rate. Relatively the number of nozzle rows affects cooling rate of flat steel greatly. Different layout parameters of the controlled cooling nozzle will be used by considering different factors. The numerical simulation results provide references for the layout of steel nozzle and controlled cooling device.

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