An Analytical Model for Chemical Etching in One Dimensional Space

2012 ◽  
Vol 445 ◽  
pp. 167-170
Author(s):  
Hossein Amirabadi ◽  
M. Rakhshkhorshid
Keyword(s):  
Analytical Model ◽  
Ferric Chloride ◽  
Chemical Etching ◽  
Dimensional Space ◽  
Etching Rate ◽  
The Other ◽  
Work Piece ◽  
Reaction Parameters ◽  
One Dimensional ◽  
Proposed Model

In this paper an analytical model for chemical etching in one dimensional space has been presented. Regarding to the special specifications of Ferric chloride, etching of an Aluminum work piece exposed to Ferric chloride etchant has been modeled. The proposed model shows that, in the condition of constant reaction parameters, etching rate is a linear function of time. Excellent agreement between the proposed model and the experimental results, published by Çakır (2008), validates the model. By generalization the proposed model, etching rate, or in the other word depth of etch in a specified time, for different materials with different etchants can be predicted.

Multi-layered diffusive convection. Part 2. Dynamics of layer evolution

2010 ◽  
Vol 651 ◽  
pp. 465-481 ◽  
Author(s):  
TAKASHI NOGUCHI ◽  
HIROSHI NIINO
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Direct Numerical Simulation ◽  
Analytical Model ◽  
The Other ◽  
One Dimensional ◽  
Turbulent Entrainment ◽  
Diffusive Convection ◽  
Two Component

Evolution of layers in an unbounded diffusively stratified two-component fluid and its dynamics are studied by means of a direct numerical simulation (DNS) and an analytical model. The numerical simulation shows that the layers grow by repeating mergings with the neighbouring layers. By analysing the results of the numerical simulation, the mechanism of the merging is examined in detail. Two modes of merging are found to exist: one is the layer vanishing mode and the other is the interface vanishing mode. The vanishings of layers and interfaces are caused by turbulent entrainment at the interfaces. Based on the analysis of the numerical model, a one-dimensional asymmetric entrainment model is proposed. In the model, each layer is assumed to interact with its neighbouring layers through simplified convective entrainment laws. The model is applied to two simple configurations of layers and is proved to reproduce the layer evolutions found in the DNS successfully.

Transformer Fault Diagnosis Based on Cluster Analysis and Statistical Theory

2010 ◽  
Vol 168-170 ◽  
pp. 1611-1614
Author(s):  
Wen Qing Zhao ◽  
Dong Xiao Niu
Keyword(s):  
Cluster Analysis ◽  
Statistical Theory ◽  
Fault Diagnosis ◽  
Concentration Distribution ◽  
Dimensional Space ◽  
The Other ◽  
Training Samples ◽  
Proposed Model ◽  
Higher Dimensional ◽  
Transformer Fault

A new method for transformer fault diagnosis based on cluster analysis and statistical theory is presented. First, the fault diagnosis results are obtained according to the distances between the state sorts of transformer. Then, the final fault diagnosis is accomplished according to the concentration distribution of typical fault gases in higher dimensional space. The proposed approach is constructing the most accuracy model from few training samples supporting. Moreover, by comparing with the other methods, it cost less time for diagnosing by the proposed model and the accuracy for transformer fault diagnosis is improved using our proposed model.

Effect of Non-Parallel Wedged Surface Contact on Loosening Performance of Preloaded Bolts Under Transverse Excitation

2011 ◽  
Author(s):  
Xianjie Yang ◽  
Sayed A. Nassar
Keyword(s):  
Analytical Model ◽  
Wedge Angle ◽  
The Self ◽  
The Other ◽  
Analytical Results ◽  
Other Hand ◽  
Transverse Excitation ◽  
Proposed Model ◽  
Surface Contact

An analytical model is proposed for investigating the effect of non-parallel (wedge) contact on the loosening performance of a preloaded bolt-nut connection under transverse cyclic excitation along the wedge direction. From the model, if the wedge angle is sufficiently small, the self-loosening may take place. On the other hand, if the wedge angle is large enough, the self-loosening caused by the back off rotation may be prevented. Experimental and analytical results show that the proposed model accurately predicts both the self-loosening performance, and it also establishes the requirements for preventing the loosening of the preloaded bolt-nut system.

Diode Circuit-based Glass Plasma-Chemical Etching Capabilities

2017 ◽  
pp. 44-63
Author(s):  
K. N. Bugorkov ◽  
H. R. Saghatelyan
Keyword(s):  
Silicate Glass ◽  
High Frequency ◽  
Chemical Etching ◽  
Etching Rate ◽  
Work Piece ◽  
Limiting Factor ◽  
Plasma Chemical ◽  
Etching Depth ◽  
Plasma Chemical Etching ◽  
The Impact

The paper discusses technological capabilities to improve a plasma-chemical etching (PCE) rate of the silicate glasses through a chromium mask in the equipment with a planar inductor located outside, which forms a high-frequency diode system. Suggests a case when the inductor in the form of a planar spiral antenna is above the work-piece.The PCE process stages were analytically studied and the limiting effects of each step that affect the etching rate and the quality of the treated surface were determined. The paper shows that for the type of equipment under consideration the stage of removing etch products from the work-piece is a quality-limiting factor for the PCE-exposed surface while the limiting factor for the etching rate is the stage of formation of chemically active particles (CAP) in plasma.The comparison of analytical results with the experimental data shows that in the considered case plasma of low density and high pressure is formed. The experimentation was aimed at studying the impact of the surface position under treatment and the working pressure in the chamber on the etching rate and the peculiarities of the etched surface formation. As a treated material, the blanks of the photomasks for integrated circuits made from Cr-covered silicate glass were considered.  The electron beam lithography method was used to create a mask for the PCE process.It was experimentally found that when a treating surface of the work-piece in plasma is “downward” the etching depth is by 5-10% more than   the etching depth of the “upward” surface. Another finding was that with raising gas flow the etching depth was twice increased as well.Optical-microscopic examinations of the etched surfaces of work-pieces have shown that there are areas with green or brown coating. Supposedly, this is due to the effect of the reverse deposition of the mask material as in the form of CrF3, CrF4 compounds that reinforce the need to look for a replacement of the chrome mask.The etching rates of 45-90 nm/min are obtained for the silicate glass, which is close in composition to the optical glass of K8 grade. This allows using the PCE in the equipment with a planar inductor located outside the chamber and realizing a high-frequency diode circuit to produce diffraction and hologram optical elements with a depth of the surface relief up to 400-500 nm.

Polar Optical Phonon Instability and Intervalley Transfer in Gallium Nitride

1998 ◽  
Vol 512 ◽  
Author(s):  
B. E. Foutz ◽  
S. K. O'leary ◽  
M. S. Shur ◽  
L. F. Eastman ◽  
B. L. Gelmont ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Analytical Model ◽  
Optical Phonon ◽  
Room Temperature ◽  
Phonon Scattering ◽  
Polar Optical Phonon ◽  
Scattering Mechanism ◽  
Loss Mechanism ◽  
One Dimensional ◽  
Optical Phonon Scattering

ABSTRACTWe develop a simple, one-dimensional, analytical model, which describes electron transport in gallium nitride. We focus on the polar optical phonon scattering mechanism, as this is the dominant energy loss mechanism at room temperature. Equating the power gained from the field with that lost through scattering, we demonstrate that beyond a critical electric field, 114 kV/cm at T = 300 K, the power gained from the field exceeds that lost due to polar optical phonon scattering. This polar optical phonon instability leads to a dramatic increase in the electron energy, this being responsible for the onset of intervalley transitions. The predictions of our analytical model are compared with those of Monte Carlo simulations, and are found to be in satisfactory agreement.

scholarly journals Assessing a Linear Nanosystem's Limiting Reliability from its Components

2008 ◽  
Vol 45 (03) ◽  
pp. 879-887 ◽  
Author(s):  
Nader Ebrahimi
Keyword(s):  
Present State ◽  
Size Range ◽  
Two Dimensions ◽  
The Other ◽  
One Dimension ◽  
Present Moment ◽  
One Dimensional ◽  
The One ◽  
Fixed Moment ◽  
Nanosized Systems

Nanosystems are devices that are in the size range of a billionth of a meter (1 x 10-9) and therefore are built necessarily from individual atoms. The one-dimensional nanosystems or linear nanosystems cover all the nanosized systems which possess one dimension that exceeds the other two dimensions, i.e. extension over one dimension is predominant over the other two dimensions. Here only two of the dimensions have to be on the nanoscale (less than 100 nanometers). In this paper we consider the structural relationship between a linear nanosystem and its atoms acting as components of the nanosystem. Using such information, we then assess the nanosystem's limiting reliability which is, of course, probabilistic in nature. We consider the linear nanosystem at a fixed moment of time, say the present moment, and we assume that the present state of the linear nanosystem depends only on the present states of its atoms.

Microfabricated Fiber Probe by Combination of Electric Arc Discharge and Chemical Etching Techniques

2012 ◽  
Vol 462 ◽  
pp. 38-41 ◽  
Author(s):  
Wan Maisarah Mukhtar ◽  
P. Susthitha Menon ◽  
Sahbudin Shaari
Keyword(s):  
Optical Fibers ◽  
Chemical Etching ◽  
Arc Discharge ◽  
Etching Rate ◽  
Electric Arc ◽  
Buffer Solution ◽  
Fiber Probe ◽  
Optical Fiber Probes ◽  
Electric Arc Discharge ◽  
Fiber Probes

In this study, optical fiber probes were fabricated by combination of electric arc discharge and chemical etching techniques. Size of tips diameters fabricated using different etching solutions were observed. When the optical fibers were pulled and heated by the electric arc discharge using a fusion splicer, fiber tips with few microns in diameter were obtained. To minimize the tips diameter, the pulled fiber probes were etched vertically for 10 minutes using two different etching solutions namely 49% HF and HF buffer solution (49% HF and 40% NH4F) with ratio of 2:1. A thick overlayer was added on top of the HF solution to prevent dangerous vapors escape to the environment. When the tapered part of the pulled fiber (FP1) was dipped into 49% HF solution, the diameter of tip was slightly decreased from 4.41μm to 1.31μm with etching rate of 5.17x10-3 μms-1. When the pulled fiber (FP2) was etched into HF buffer solution, the etching rate was increased up to 52.35% with the etching rate of 10.85x10-3μms-1. The tip diameter was reduced from 7.01μm to 468.9 nm in diameter. Combination of “heat and pull” technique with chemical etching by using HF buffer solution produced fiber probe with small tip diameter.

Modeling of Shear Rheological Behavior of Uncured Rubber Melt

2020 ◽  
Vol 30 (1) ◽  
pp. 130-137
Author(s):  
Hengxiao Yang ◽  
Qimian Mo ◽  
Hengyu Lu ◽  
Shixun Zhang ◽  
Wei Cao ◽  
...  
Keyword(s):  
Shear Rate ◽  
Constitutive Model ◽  
Incompressible Fluid ◽  
Rheological Behavior ◽  
Rheological Characteristics ◽  
One Dimensional ◽  
Ptt Model ◽  
Rate Region ◽  
Proposed Model ◽  
Rheological Experiments

AbstractTo describe uncured rubber melt flow, a modified Phan–Thien–Tanner (PTT) model was proposed to characterize the rheological behavior and a viscoelastic one-dimensional flow theory was established in terms of incompressible fluid. The corresponding numerical method was constructed to determine the solution. Rotational rheological experiments were conducted to validate the proposed model. The influence of the parameters in the constitutive model was investigated by comparing the calculated and experimental viscosity to determine the most suitable parameters. The uncured rubber viscosity was 3–4 orders larger than that of plastic and did not have a visible Newtonian region. Compared with the Cross-Williams-Landel-Ferry (Cross-WLF) and original PTT models, the modified PTT model can describe the rheological characteristics in the entire shear-rate region if the parameters are set correctly.

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