• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.366-369
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• 2002

Two artificial neural networks (ANN) are used to model the electric coupling probe in the combline resonators. One is used to analyze and synthesize the electric probe, and the other is used to correct errors between the results of the analysis and the synthesis ANNs and the fabrication results. The ANNs for the analysis and the synthesis of the electric probe are trained using the physical dimensions of the electric probe and the corresponding coupling bandwidth which is obtained using the finite element method. The ANNs for the error correction are trained using a very small set of the measurement results. Once trained, the ANN models provide the correct result approaching the accuracy of the measurement. The results from the ANN models show fairly good agreement with those of the measurement and they can be used as good initial design values.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2713-2722
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• 2000

When designing a gear drive, designers should specify tolerances reasonably considering accuracy, cost, and manufacturing capability. In field design, however, designers mostly assign adequate tolerance without correlations between parts and assembly, resulting in iterative design dependent on experts know-how. In order to resolve this, the tolerance design system for a cylindrical gear drive is developed both to support tolerance design automation and to synthesize design processes of part and assembly tolerances. In this research, part tolerances are designed with the databases constructed by ISO, Ks, JIS and bearing catalogue, Assemble tolerance, that is, backlash tolerance is designed by synthesizing part design tolerances stochastically using the formulated assembly relations. This system can include part tolerance and fitting accuracy of shaft adn bearing in practical design. In addition, this system provides field-designers with a synthetic guideline for tolerance design of a gear drive.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.899-904
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• 2003

Tight integration of product design and process planning in the early design stage would make bigger impact as wider spectrum of design and manufacturing alternatives can be pursued and evaluated. Thus the development of systematic computer-based support for this integration is desirable. For this integration and process planning in the early design stage. the systematic method to synthesize shape of part from functional requirements is crucial. This research presents the methods of functional decomposition from overall function or product and synthesizing shape of part based on functional relations extracted from functional decomposition using planetary gear transmission system as an example.

• The Journal of the Acoustical Society of Korea
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• v.27 no.1E
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• pp.11-16
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• 2008

In this paper, a pitch cycle waveform (PCW) is extracted, quantized, and interpolated in a time domain to synthesize high-quality speech at low bit rates. The pre-alignment technique is proposed for the accurate and efficient PCW extraction, which predicts the current PCW position from the previous PCW position assuming that pitch periods evolve slowly. Since the pitch periods are different frame by frame, the original PCW is converted into the fixed-dimension PCW using the dimension-conversion method, and subsequently quantized by code-excited linear predictive (CELP) coding. The excitation signal for the linear predictive coding (LPC) synthesis filter is generated using the time-domain interpolation and interlink of the quantized PCW's. The coder operates at 4.2 kbit/s and 3.2 kbit/s depending on the pitch period. Informal listening test demonstrates the effectiveness of the proposed coding scheme.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.199-205
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• 1981

7-Alkyl-1-carboxyphenazine derivatives, bearing butyl or octyl group, were synthesize by the reaction of anthranilic acid with 3-nitroalkylbenzene, prepared from aniline and alcohols as starting materials through alkylation of 3-nitro-4-aminoalkylbenzene. And the products were also identified by elementary analysis, IR and NMR spectra. Surface tension of these derivatives in aqueous solution was determined. And also Antibiotic activity of these derivatives was tested, using Gram positive and negative bacillus and fungi. It showed that the antibiotic activity of these alkyl-substituted 1-carboxyphenazine derivatives was stronger than that of the 1-carboxyphenazine.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.959-964
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• 1992

This study treats the method for kinematic modeling of the biped walking robot, for synthesizing various gait trajectories, and for calculating adequate values of the joint torque inside the stable region. To synthesize various and anthropomorphic walking easily, the gait trajectory is specified by a set of ten walking prameters, and the trunk motion equation is derived by the zero moment point and the gait trajectory. By distributing ground reaction force and moment reduced at the zero moment point to the both feet, the joint torque equation can be derived readily, and according to this equation, the joint torque to stable walking can be computed.

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.428-432
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• 2005

Squarylium or squaraine dyes are derived from 1,2-dihydroxycyclobuten-3,4-dione, otherwise known as squaric acids. They are two principal types: the 1,2-bisdonorsubstituted derivatives, and the 1,3-bisdonorsubstituted derivatives. The former are essentially merocyanines and have no distinctive properties, whereas the latter represent a unique type of chromophore, which is neither a merocyanines nor cyanine and has exceptional light absorption characteristics. They also have many functional applications based on their special properties. Thus it was the objective of this research project to synthesize a range of 1,3-squarylium dyes of widely differing structural types, and to investigate their light absorption and fluorescence properties in general, and the color change properties of appropriate examples in particular. Also in this study, the various pHinduced colour change processes were examined.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2575-2580
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• 2010

We present a method for chemically reducing silver alkylcarbamate complex with hydrazine to synthesize silver nanocolloids in an organic solvent using polyvinylpyrrolidone (PVP) as the stabilizer. To determine the optimal conditions for preparing stable silver colloids of controlled size and shape, the silver 2-ethylhexylcarbamate (Ag-EHCB) complex, PVP, hydrazine, and 2-propanol solvent concentrations in the reaction mixture were varied. The initial colloid has a mean particle diameter of 5-80 nm, and it exhibits an absorption band with various shapes in the UV region with a maximum near 420 nm. UV-vis spectroscopy, TEM, and X-ray diffraction techniques were used to investigate the formation and growth process of the metallic silver nanocolloids.

• Journal of Magnetics
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• v.6 no.1
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• pp.1-4
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• 2001

We have used acetic acids ethanol and distilled water as a solvent to synthesize $La_{2/3}Sr_{1/3}Mn_{0.99}{^{57}}Fe_{0.01}O_3$(LSMFO) precursor. Crack-free LSMFO granular polycrystalline thin films have been deposited on thermally oxidized silicon substrates by spin coaling. The dependence of crystallization, surface morphology, magnetic and transport properties on annealing temperature was investigated. With increasing annealing temperature, the metal-semiconductor (insulator) transition temperature and the magnetic moment decrease while the resistivity increases. The lattice constants remain almost unchanged. For LSMFO thin films, spin-dependent interfacial tunneling and/or scattering magnetoresistance were observed. Our results indicate that the annealing temperature is very important in determining the intrinsic and extrinsic magnetotransport properties.

• YAKHAK HOEJI
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• v.44 no.3
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• pp.272-278
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• 2000

The antiinflammatory mechanism of NSAIDs is attributed to the reduction of prostaglandin synthesis by the direct inhibition of cyclooxygenase. Inhibition of prostaglandin production in organs such as stomach and kidney can result in gastric lesions, nephrotoxicity and increased bleeding. In this study, newly designed COX-2 inhibitors, synthesized 1,2-benzothiazine derivatives, were screened in vitro for selectivity of COX-1 and COX-2 inhibition properties. Lead compounds in the structure-activity relationship were studied to synthesize new highly selective COX-2 inhibitors.13 determine inhibitory effect of COX-2, synthesized 1,2-benzothiazine derivatives were screened with accumulation of prostaglandin by lipopolysaccharide (LPS) in aspirin-treated macrophages and murine macropharge cell. Some of synthesized 1,2-benzothiazine derivatives were shown to be effective as selective COX-2 inhibitory activity. Others exhibited a preferential inhibition of COX-2, although some COX-1 inhibitory activity was still present. As a conclusion, simple monomer derivatives were more active than dimer derivatives. Substitution of halogen (Br, C1) on the benzothiazine nucleus slightly enhanced inhibition activity.