• Computers and Concrete
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• v.9 no.5
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• pp.327-340
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• 2012

The search for a design that meets both performance and safety, with minimal cost and lesser environmental impact was always the goal of structural engineers. In general, the design of conventional reinforced concrete structures is an iterative process based on rules of thumb established from the personal experience and intuition of the designer. However, such procedure makes the design process exhaustive and only occasionally leads to the best solution. In such context, this work presents the development and implementation of a mathematical formulation for obtaining optimal sections of reinforced concrete columns subjected to uniaxial flexural compression, based on the verification of strength proposed by the Brazilian standard NBR 6118 (ABNT 2007). To minimize the cost of the reinforced concrete columns, the Simulated Annealing optimization method was used, in which the amount and diameters of the reinforcement bars and the dimensions of the columns cross sections were considered as discrete variables. The results obtained were compared to those obtained from the conventional design procedure and other optimization methods, in an attempt to verify the influence of resistance class, variations in the magnitudes of bending moment and axial force, and material costs on the optimal design of reinforced concrete columns subjected to uniaxial flexural compression.

• Korean Journal of Materials Research
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• v.20 no.7
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• pp.351-355
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• 2010

Transparent conducting aluminum-doped ZnO thin films were deposited using a sol-gel process. In this study, the important deposition parameters were investigated thoroughly to determine the appropriate procedures to grow large area thin films with low resistivity and high transparency at low cost for device applications. The doping concentration of aluminum was adjusted in a range from 1 to 4 mol% by controlling the precursor concentration. The annealing temperatures for the pre-heat treatment and post-heat treatment was $250^{\circ}C$ and 400-$600^{\circ}C$, respectively. The SEM images show that Al doped and undoped ZnO films were quite uniform and compact. The XRD pattern shows that the Al doped ZnO film has poorer crystallinity than the undoped films. The crystal quality of Al doped ZnO films was improved with an increase of the annealing temperature to $600^{\circ}C$. Although the structure of the aluminum doped ZnO films did not have a preferred orientation along the (002) plane, these films had high transmittance (> 87%) in the visible region. The absorption edge was observed at approximately 370 nm, and the absorption wavelength showed a blue-shift with increasing doping concentration. The ZnO films annealed at $500^{\circ}C$ showed the lowest resistivity at 1 mol% Al doping.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.1
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• pp.34-40
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• 2012

We have developed a highly sensitive inspection technique based on an electron beam inspection for detecting the contact failure of a poly-Si plugged layer. It was difficult to distinguish the contact failure from normal landing plugs with high impedance. Normally, the thermal annealing method has been used to decrease the impedance of poly-Si plugs and this method increases the difference of charged characteristics and voltage contrast. However, the additional process made the loss of time and broke down the device characteristics. Here, the interval scanning method without thermal annealing was effectively applied to enhance the difference of surface voltage between well-contacted poly-Si plugs and incomplete contact plugs. It is extremely useful to detect the contact failures of non-annealed plug contacts with high impedance.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.103-108
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• 2017

In the ubiquitous environment, there has been a problem of transmitting data from various sensors at a long distance. Especially, in the process of integrating data arriving at different locations, data having different property values of data or having some loss in data had to be processed. This paper present a method to analyze such data. The core of this method is to define an objective function suitable for the problem and to develop an algorithm that can optimize this objective function. The objective function is used by modifying the OCS function. MFA (Mean Field Annealing), which was able to process only binary data, is extended to be applicable to fields with continuous values. It is called CMFA and used as an optimization algorithm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.310-313
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• 2002

Structures obtained with a direct boning of two FZ silicon wafers joined in such a way that a smooth surface of one wafer was attached to the grooved surface of the other were studied. A square net of grooves was made with a conventional photo lithography process. After high temperature annealing the appearance of voids and the rearrangement of structural defects were observed with X-ray diffraction topography techniques. It was shown that the formation of void free grooved boundaries was feasible. In the cases when particulate contamination was prevented, the voids appeared in the grooved structures could be eliminated with annealing. Since it was found that the flattening was accompanied with plastic deformation, this deformation was suggested to be intensively involved in the process of void removal. A model was proposed explaining the interaction between the structural defects resulted in "a dissolution" of cavities. The described processes may occur in grooved as well as in smooth structures, but there are the former that allow to manage air traps and undesirable excess of dislocation density. Grooves can be paths for air leave. According to the established mechanisms, if not outdone, the dislocations form local defect arrangements at the grooves permitting the substantial reduction in defect density over the remainder of the interfacial area.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.363-367
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• 2015

This paper reports on thermally adjusted graphene oxide (GO) as the hole transport layer (HTL) for organic light-emitting diodes (OLEDs). GO is generally not suitable for HTL of OLEDs because of intrinsic specific resistance. In this paper, the specific resistance of GO is adjusted by the thermal annealing process. The optimum specific resistance of HTL is found to be $10^2{\Omega}{\cdot}m$, and is defined by the maximum current efficiency of OLEDs, 2 cd/A. In addition, the reasons for specific resistance change are identified by x-ray photoelectron spectroscopy (XPS). First, the XPS results show that several functional groups of GO were detached by thermal energy, and the amount of epoxide changed substantially following the temperature. Second, the full width at half maximum (FWHM) of the C-C bond decreased during the process. That means the crystallinity of the graphene improved, which is the scientific basis for the change in specific resistance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.9 s.240
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• pp.1243-1252
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• 2005

A current trend of design methodologies is to make engineers objectify or automate the decision-making process. Numerical optimization is an example of such technologies. However, in numerical optimization, the uncertainties are uncontrollable to efficiently objectify or automate the process. To better manage these uncertainties, the Taguchi method, reliability-based optimization and robust optimization are being used. To obtain the target performance with the maximum robustness is the main functional requirement of a mechanical system. In this research, a design procedure for global robust optimization is developed based on the kriging and global optimization approaches. The DACE modeling, known as the one of Kriging interpolation, is introduced to obtain the surrogate approximation model of the function. Robustness is determined by the DACE model to reduce real function calculations. The simulated annealing algorithm of global optimization methods is adopted to determine the global robust design of a surrogated model. As the postprocess, the first order second-moment approximation method is applied to refine the robust optimum. The mathematical problems and the MEMS design problem are investigated to show the validity of the proposed method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.49-50
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• 2005

Nitrogen and phosphorus ions were implanted into ZnO thin film fabricated by pulsed laser deposition. ion implanted ZnO thin films were annealed from $700^{\circ}C$ to $1000^{\circ}C$ using rapid thermal annealing process. The electron concentration was changed form $10^{20}$ to $10^{18}/cm^3$. Effect of nitrogen and phosphorus in ZnO thin films was certified and the structural and optical properties of nitrogen and phosphorus doped ZnO thin films depending on concentration of nitrogen and phosphorus were investigated.

• Journal of the Korean Ceramic Society
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• v.38 no.10
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• pp.871-875
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• 2001

Cobalt silicidation at sidewall spacer edge of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with post annealing treatment for capacitor forming process has been investigated as a function of dopant species. Cobalt silicidation of nMOSFET with n-type Lightly Doped Drain (LDD) and pMOSFET with p-type LDD produces a well-developed cobalt silicide with its lateral growth underneath the sidewall spacer. In case of pMOSFET with n-type LDD, however, a void is formed at the sidewall spacer edge with no lateral growth of cobalt silicide. The void formation seems to be due to a retarded silicidation process at the LDD region during the first Rapid Thermal Annealing (RTA) for the reaction of Co with Si, resulting in cobalt mono silicide at the LDD region. The subsequent second RTA converts the cobalt monosilicide into cobalt disilicide with the consumption of Si atoms from the Si substrate, producing the void at the sidewall spacer edge in the Si region. The void formed at the sidewall spacer edge serves as a resistance in the current-voltage characteristics of the pMOSFET device.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.575-578
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• 2016

The thermal endurance of fiber Bragg gratings (FBGs), written with the aid of 193-nm ArF excimer laser irradiation on H₂-loaded Ge/B codoped silica fiber, and pretreated with a CO₂ laser and a subsequent slow cooling process, is investigated. These treated gratings show relatively less degradation of grating strength during the thermal annealing procedure. The thermal decay characteristics of treated and untreated fiber, recorded over a time period of 9 hours, have been compared. The effect on the Bragg transmission depth (BTD) and the center-wavelength shift, as well as the growth of refractive-index change during the grating inscription process for both treated and untreated fiber, are analyzed.