• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1249-1254
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• 2010

The bogie structure of center guided type monorail has been applied to Incheon Wolmi Eunha monorail at first in the world, and aluminum alloy material bogie is first ever introduced in Korea. Since bogie transfers vertical and horizontal loads to the track and guide rail as an essential system, its structure should have enough durability and secure excellent operation performance and ride quality. This study presents a suitable structure for center guided type monorail, a system combination method for bogie operation performance and riding quality, and a solution for better bogie frame durability.

• Biomolecules & Therapeutics
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• v.2 no.1
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• pp.34-38
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• 1994

In order to investigate the structure-activity relationships of the stereoisomers of angiotensin converting enzyme inhibitors, captopril and its derivatives were selected as model compounds. In vitro enzymatic activities of them depend on the symmetry at the asymmetric carbons. Especially, the alanyl carbon should have the S configuration to be biologically active. But the demethylated captopril having the achiral carbon also shows the activity although it is less active than captopril. Seven stereoisomers of captopril and its derivatives were chosen and their acidic and ionic forms were used for molecular dynamics simulations. Four computer simulations were practiced for each model compound in order to obtain the good condition for simulation to explain the experimental structure-activity relationships. From the computer simulation results, relativistic movements of three well-known pharmacophoric sites, carboxylate carbon, carbonyl oxygen, and sulfur atoms, were analyzed. Good results were obtained from the aqueous solution molecular dynamics simulation with ionic forms of model compounds. Active model compounds have the pharmacophoric areas of 6.08 to 6.38 $\AA$$^2$and the similarity in the geometrical data. But inactive ones have the largely deviated values of 4.51 to 4.87 $\AA$$^2$from those of active ones.

• Ceramist
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• v.23 no.2
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• pp.114-131
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• 2020

Fracture in the titanium carbonitride-metal composites occurs by crack propagation through the carbonitride grains or in the interfaces. Thus, intrinsic properties of the carbonitride need to be enhanced and the interfaces should be also modified to coherent structure to strengthen the composites. Especially, interfacial structure can be the main factor to determine the mechanical properties of titanium carbonitride-metal composites because the interfaces between carbonitride grains and metallic phase are weak parts due to heterogeneous nature of carbonitride and metallic phase. In this paper, methodologies for improving the interfacial structure of titanium carbonitride-metal composites are suggested. Total area of the interfaces can be reduced using solid solution type carbonitrides as raw materials instead of a mixture of various carbonitrides in the composites. Also, synthesis of titanium carbonitride-metal composite powders and the low-temperature sintering of the composite powders for short time can be the way for formation of coherent interfaces. The sintering of the composite powders for short time at low temperature can reduce the potential of formation of interfaces by dissolution and precipitation of carbonitride in the liquid metal. As a result of formation of coherent boundaries due to low-temperature and short-time sintering, interfaces between titanium carbonitride grains and metallic phase have the favorable structure for the enhanced fracture toughness. It is believed that the low-temperature sintering of solid solution type composite powders for short time can be the way to improve the low toughness of the titanium carbonitride-metal composites.

• Journal of the Korean Magnetic Resonance Society
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• v.13 no.2
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• pp.143-153
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• 2009

Luteinizing Hormone Releasing Hormone (LHRH) is composed of 10 amino acids, and is best known as a neurotransmitter. Because of the 80% homology in animals, much more concerns have focused on the substances that have similar functions or can control LHRH. Ni, Cu-LHRH complexes were synthesized. The degree of complexation was monitored by $^1H,\;^{13}C$-NMR chemical shifts, and final products were identified by ESI-Mass spectrum. Solution-state structure determination of Ni-LHRH complex was accomplished by using NMR results and NMR-based distance geometry (DG). Interproton distances from nuclear Overhauser effect spectroscopy (NOESY) were utilized for the molecular structure determination. Results were compared with previous structures obtained from energy minimization and other spectroscopic methods. Structure obtained in this study has a cyclic conformation which is similar to that of energy minimized, and exhibits a specific a-helical turn with residue numbers (2~7) out of 10 amino acids. Comparison of chemical shifts and EPR studies of Ni, Cu-LHRH complexes exhibit that Ni-LHRH complex has same binding sites with the 4-coordination mode as in Zn-LHRH complex.

• Earthquakes and Structures
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• v.13 no.6
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• pp.589-598
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• 2017

In this paper, dynamic response of the horizontal concrete beam subjected to seismic ground excitation is investigated. The structure is reinforced by $Fe_2O_3$ nanoparticles which have the magnetic properties. The hyperbolic shear deformation beam theory (HSDBT) is used for mathematical modeling of the structure. Based on the Mori-Tanaka model, the effective material properties of concrete beam is calculated considering the agglomeration of $Fe_2O_3$ nanoparticles. Applying energy method and Hamilton's principle, the motion equations are derived. Harmonic differential quadrature method (HDQM) along with Newmark method is utilized for numerical solution of the motion equations. The effects of different parameters such as volume fraction and agglomeration of $Fe_2O_3$ nanoparticles, magnetic field, boundary conditions and geometrical parameters of concrete beam are studied on the dynamic response of the structure. In order to validation of this work, an exact solution is used for comparing the numerical and analytical results. The results indicated that applying magnetic field decreases the of the structure up to 54 percent. In addition, increase too much the magnetic field (Hx>5e8 A/m) does not considerable effect on the reduction of the maximum dynamic displacement.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1310-1313
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• 1997

Application of eddy current sensing principle for the non-contact estimation of very low concentration of electrolytic solution is presented in this paper. for this application, a new, simple, low-cost, low-power structure for the eddy current sensor is proposed. By measuring the eddy current produced in the conducting electrolytic solution, the concentration is estimated. Therefore, the unknown concentration can be estimated comparing with the database which is prepared as the relation between the change in inductance and various concentrations of electrolytic solution. The concentration, as low as l ppm of the solutioin can be detected by this sensor. It was tested on various low concentration solutions of NaCl. It shows distinct response for various concentrations.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.3
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• pp.97-103
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• 2018

The objective of this study is to develop the mechanical properties of AlSiCu aluminum alloy by the two-step solution heat treatment. The microstructure of gravity casting specimen represents a typical dendrite structure having a secondary dendrite arm spacing (SDAS) of 40 mm. In addition to the Al matrix, a large amount of coarsen eutectic Si phase, $Al_2Cu$ intermetallic phase, and Fe-rich phases are generated. The eutectic Si phases are fragmented and globularized with solution heat treatment. Also, the $Al_2Cu$ intermetallic phase is resolutionized into the Al matrix. The $2^{nd}$ solution temperature at $525^{\circ}C$ might be a optimum condition for enhancement of mechanical properties of AlSiCu aluminum alloy.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.858-863
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• 2004

In the optimized design of an actual structure, the design variable should be selected among any certain values or corresponds to a discrete design variable that needs to handle the size of a pre-formatted part. Various algorithms have been developed for discrete design. As recently reported, the sequential algorithm with orthogonal arrays(SOA), which is a local minimum search algorithm in discrete space, has excellent local minimum search ability. It reduces the number of function evaluation using orthogonal arrays. However it only finds a local minimum and the final solution depends on the initial value. In this research, the genetic algorithm, which defines an initial population with the potential solution in a global space, is adopted in SOA. The new algorithm, sequential algorithm with orthogonal arrays and genetic algorithm(SOAGA), can find a global solution with the properties of genetic algorithm and the solution is found rapidly with the characteristics of SOA.

• Journal of the Korean institute of surface engineering
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• v.41 no.1
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• pp.23-27
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• 2008

The effect of solution agitation on the copper electroless deposition process of ULSI (ultra large scale integration) interconnections was investigated by using physical, electrochemical and electrical techniques. It was found that proper solution agitation was effective to obtain superconformal copper configuration within the trenches of $130{\sim}80nm$ width. The transition of open potential during electroless deposition process showed that solution agitation induced compact structure of copper deposits by suppressing mass transfer of cuprous ions toward substrate. Also, the specific resistivity of copper layers was lowered by increasing agitation speed, which made the deposited copper particles smaller. Considering both copper deposit configuration and electric property, around 500 rpm of solution agitation was the most suitable for the homogeneous electroless copper filling within the ultra-fine patterns.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.197-211
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• 2002

In this paper, we propose a multi-Criteria decision making approach to address the problem of finding the best possible solution in credit unions. Sensitivity analysis on the priority structure of the goals has been performed to obtain all possible solutions. The study uses the Euclidean distance method to measure distances of all possible solutions from the identified ideal solution. The possible optimum solution is determined from the minimum distance between the ideal solution and other possible solutions of the Problem.