• Macromolecular Research
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• 제14권2호
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• pp.132-139
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• 2006

The dispersion of organoclay in ethylene propylene diene terpolymer (EPDM) matrix was correlated with the rheological and swelling properties of nanocomposites. X-ray diffraction pattern (XRD) and transmission electron microscopic (TEM) analysis exhibited the disordered-intercalated structure of EPDM/organoclay nanocomposite. The extent of the disordered phase increased with increasing organoclay content up to a limiting value of 3 wt% after which equilibrium tended towards intercalation. The dispersion effect of organoclay in EPDM matrix was clarified by the physicochemical properties like rheological response and swelling thermodynamics in toluene. The increase in viscoelastic properties of EPDM nanocomposite with increasing organoclay content up to 3 wt%, followed by a subsequent decrease up to 4 wt%, was correlated in terms of the disordered and ordered states of the dispersed nano-clay sheets. Swelling measurements revealed that the change in entropy of the swelling increased with the increase in disorder level but decreased with the increase in intercalation level of organoclay in the disordered-intercalated nanocomposite. The increase in solvent uptake was comparable with the free volume in EPDM matrix upon inclusion of silicate particles, whereas the inhibition in solvent uptake for higher organoclay loading was described by bridging flocculation.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권4호
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• pp.211-216
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• 2003

This work describes a 3 V 12b 100 MS/s CMOS digital-to-analog converter (DAC) for high-speed communication system applications. The proposed DAC is composed of a unit current-cell matrix for 8 MSBs and a binary-weighted array for 4 LSBs, trading-off linearity, power consumption, chip area, and glitch energy with this process. The low-glitch switch driving circuits are employed to improve linearity and dynamic performance. Current sources of the DAC are laid out separately from the current-cell switch matrix core block to reduce transient noise coupling. The prototype DAC is implemented in a 0.35 um n-well single-poly quad-metal CMOS technology and the measured DNL and INL are within ${\pm}0.75$ LSB and ${\pm}1.73$ LSB at 12b, respectively. The spurious-free dynamic range (SFDR) is 64 dB at 100 MS/s with a 10 MHz input sinewave. The DAC dissipates 91 mW at 3 V and occupies the active die area of $2.2{\;}mm{\;}{\times}{\;}2.0{\;}mm$

• Structural Engineering and Mechanics
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• 제26권1호
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• pp.43-68
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• 2007

Using the Mindlin-Reissner plate theory, many quadrilateral plate bending elements have been developed so far to analyze thin and moderately thick plate problems via displacement based finite element method. Here new formulation has been made to analyze thin and moderately thick plate problems using force based finite element method called Integrated Force Method (IFM). The IFM is a novel matrix formulation developed in recent years for analyzing civil, mechanical and aerospace engineering structures. In this method all independent/internal forces are treated as unknown variables which are calculated by simultaneously imposing equations of equilibrium and compatibility conditions. In this paper the force based new bilinear quadrilateral plate bending element (MQP4) is proposed to analyze the thin and moderately thick plate bending problems using Integrated Force Method. The Mindlin-Reissner plate theory has been used in the formulation of this element which accounts the effect of shear deformation. Standard plate bending benchmark problems are analyzed using the proposed element MQP4 via Integrated Force Method to study its performance with respect to accuracy and convergence, and results are compared with those of displacement based 4-node quadrilateral plate bending finite elements available in the literature. The results are also compared with the exact solutions. The proposed element MQP4 is free from shear locking and works satisfactorily in both thin and moderately thick plate bending situations.

• 한국동물위생학회지
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• 제22권1호
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• pp.15-23
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• 1999

A multiresidue, simple and rapid isolation technique known as matrix-solid phase dispersoin (MSPD) for the extraction and quantitative gas chromatographic/electron capture detection (GC/ECD) determination of 14 organochlorinated pesticides($\alpha$-BHC, ($\beta$-BHC, ($\gamma$-BHC, aldrin, dieldrin, endrin, heptachlor, ($\alpha$-endosulfan, ($\beta$-endosulfan, endosulfan sulfate, p,p'-DDE, o,p'-DDD, p,p'-DDD, p,p'-DDT) from meat fats. The 14 pesticide were fortified into meat fat(0.5g) and blend with 2g $C_{18}$, $C_{18}$meat fat matrix blend and 2g activated florisil comprise an extraction column from which the pesticides are eluted by adding 8ml acetonitrile. Then 2${\mu}\ell$ of the eluate is analyzed by GC/ECD. Unfortified blank controls are tested similarly. The eluate contained all the pesticide analytes and was free of interfering coextractants. Recovery rate(31.3-500ng/g) were ranged from 80$\pm$4% to 97$\pm$4%. Any organochlorinated pesticides were not detected in 120 samples of beef and pork collected from slaughter houses in Kyeonggi province.

• Journal of Information Processing Systems
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• 제8권2호
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• pp.359-374
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• 2012

In this paper, we propose a new machine vision algorithm for automatic defect detection on patterned textures with the help of texture-periodicity and the Jensen-Shannon Divergence, which is a symmetrized and smoothed version of the Kullback-Leibler Divergence. Input defective images are split into several blocks of the same size as the size of the periodic unit of the image. Based on histograms of the periodic blocks, Jensen-Shannon Divergence measures are calculated for each periodic block with respect to itself and all other periodic blocks and a dissimilarity matrix is obtained. This dissimilarity matrix is utilized to get a matrix of true-metrics, which is later subjected to Ward's hierarchical clustering to automatically identify defective and defect-free blocks. Results from experiments on real fabric images belonging to 3 major wallpaper groups, namely, pmm, p2, and p4m with defects, show that the proposed method is robust in finding fabric defects with a very high success rates without any human intervention.

• 한국지진공학회논문집
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• 제8권2호
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• pp.45-53
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• 2004

본 연구에서는 자유진동, 조화하중, 그리고 백색잡음실험을 통해 얻어지는 진동수, 감쇠비, 모드 벡타와 같은 구조물의 모드정보를 이용하여 강성행렬과 감쇠행렬을 구성하였다. 입력신호로는 지진하중을 모사 하는 바닥판 가속도를 이용하였고, 출력신호는 각층 절대가속도를 사용하였다. 각각의 실험에서 얻어지는 구조물 모드정보의 제한조건과 그에 따른 시스템 식별 모델들의 특성을 비교하였다. 본 연구의 결과는 진동대 실험을 위한 기초적인 동적 실험 및 분석에 이용될 수 있을 것으로 판단된다.

• 대한두경부종양학회지
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• 제35권1호
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• pp.21-23
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• 2019

Recent studies have reported on the reconstruction of oral mucosal defects using acellular dermal matrix (ADM). This case report describes the reconstruction of a soft-palate mucosal defect using ADM. A 43-year-old man developed a $2.5cm{\times}3cm$ soft-palate mucosal defect after the removal of a lump on the soft palate andreconstructed the defect using ADM without further complications. Reconstruction of the soft palate with ADM could be more convenient than traditional methods including primary closure, skin graft, and local or free flap without complications.

• Earthquakes and Structures
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• 제16권1호
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• pp.109-118
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• 2019

This study, analyses the seismic response for a rigid massless square foundation resting on a viscoelastic soil layer limited by rigid bedrock. The foundation is subjected either to externally applied forces or to obliquely incident seismic body or surface harmonic seismic waves P, SV and SH. A 3-D frequency domain BEM formulation in conjunction with the thin layer method (TLM) is adapted here for the solution of elastodynamic problems and used for obtained the seismic response. The mathematical approach is based on the method of integral equations in the frequency domain using the formalism of Green's functions (Kausel and Peck 1982) for layered soil, the impedance functions are calculated by the compatibility condition. In this study, The key step is the characterization of the soil-foundation interaction with the input motion matrix. For each frequency the impedance matrix connects the applied forces to the resulting displacement, and the input motion matrix connects the displacement vector of the foundation to amplitudes of the free field motion. This approach has been applied to analyze the effect of soil-structure interaction on the seismic response of the foundation resting on a viscoelastic soil layer limited by rigid bedrock.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.195-201
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• 2005

This paper discusses the problem of positive real control for uncertain 2-D linear discrete time singular Roesser models (2-D SRM) with time-invariant norm-bounded parameter uncertainty. The purpose of this study is to design a state feedback controller such that the resulting closed-loop system is acceptable, jump modes free and stable, and achieves the extended strictly positive realness for all admissible uncertainties. A version of positive real lemma for the 2-D SRM is given in terms of linear matrix inequalities (LMIs). Based on the lemma, a sufficient condition for the solvability of the positive real control problem is derived in terms of bilinear matrix inequalities (BMIs) and an iterative procedure for solving the BMIs is proposed.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.524-532
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• 2005

This paper concerns delay-dependent guaranteed cost control (GCC) problem for a class of linear state-delayed systems with norm-bounded time-varying parametric uncertainties. By incorporating the free weighing matrix approach developed recently, new delay-dependent conditions for the existence of the guaranteed cost controller are presented in terms of matrix inequalities for both nominal state-delayed systems and uncertain state-delayed systems. An algorithm involving convex optimization is proposed to design a controller achieving a suboptimal guaranteed cost such that the system can be stabilized for all admissible uncertainties. Through numerical examples, it is shown that the proposed method can yield less guaranteed cost than the existing delay-dependent methods.