• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.168-170
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• 1987

The reaction between 1-benzyl-3-carbamoyl-1,4-dihydropyridine (BNAH) 1 and various 1-arylpyridinium salts 2, and the reaction between 1-(4-methylphenyl)-1,4-dihydropyridine 4b and 1-aryl-3-carbamoylpyridinium (1-arylnicotinamide) salts 5 were carried out. The extents of reaction in equilibrium were estimated by nmr integration data. The equilibrium constants for the reactions, K, and the standard Gibbs free energy changes for the reduction of the pyridinium salts to the corresponding 1,4-dihydropyridines ${\Delta}G^{\circ}'$ were evaluated. The Hammett plot of log K for the reaction between 1 and 2, and ${\Delta}G^{\circ}'$ against ${\sigma}_p$ of the substituents in 1-aryl moiety shows linear correlation with the reaction constant ${\rho}$ of 9.4 (for log K vs ${\sigma}_p$) and -54.5 KJ/mole (for ${\Delta}G^{\circ}'$ vs ${\sigma}_p$). It was found that 1-aryl-1,4-dihydropyridines have much higher reducing power than the corresponding 1-aryl-1,4-dihydronicotinamides, and the power is affected greatly by the electron-withdrawing ability of the substituents in aryl group. The reactions were utilized for preparation of 1,4-dihydropyridines bearing highly electron-withdrawing groups such as 4-nitrophenyl and 2,4-dinitrophenyl, which could not be obtained by conventional dithionite reduction of the corresponding pyridinium salts due to the base-labile nature of the salts.

• 대한물리의학회지
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• 제6권3호
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• pp.293-301
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• 2011

Purpose : The purposes of this study were to investigate the age-related difference in balance ability in the elderly over 65 years and to verify the clinical usefulness of the functional reach test (FRT) for balance evaluation of the elderly through the sensory organization test (SOT). Methods : The subjects were forty-six community dwelling elderly people over 65 years old in order to verify the correlation of balance measures and to compare the balance ability. Balance was measured using the FRT and the six sub-equilibrium scores and the composite equilibrium score of the SOT. Pearson's product correlation coefficient was used to evaluate the relationships among these measurements of balance. Results : There was a significant difference in functional reach by age in the elderly (p<.01). There was a significant negative correlation between the FRT and the age of the elderly (r=-.396, p<.01). There was also significant high positive correlation between the FRT and the eye closed sway surface (EC/SS) (r=.789, p<.01), and composite equilibrium score (r=.548, p<.01) of the SOT. Conclusion : Thus, it is possible to use the FRT as a quantitative measure of balance, rather than the SOT, which is more expensive and complicated to evaluate elderly people. According to the results of this study, the use of the FRT is required clinically to objectively measure the balance of elderly people in the future.

• 한국산업융합학회 논문집
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• 제4권3호
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• pp.329-337
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• 2001

This simulator is developed for the analysis of a MOSFET based on Thermally Coupled Energy Transport Model(TCETM). The simulator has the ability to calculate not only stationary characteristics but also non - stationary characteristics of a MOSFET. It solves basic semiconductor devices equations including Possion equation, current continuity equations for electrons and holes, energy balance equation for electrons and heat flow equation, using finite difference method. The conventional semiconductor device simulation technique, based on the Drift-Diffusion Model (DDM), neglects the thermal and other energy-related properties of a miniaturized device. I, therefore, developed a simulator based on the Thermally Coupled Energy Transport Model (TCETM) which treats not only steady-state but also transient phenomena of such a small-size MOSFET. In particular, the present paper investigates the breakdown characteristics in transient conditions. As a result, we found that the breakdown voltage has been largely underestimated by the DDM in transient conditions.

• 대한전기학회논문지:전력기술부문A
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• 제51권8호
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• pp.403-408
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• 2002

As the electricity industry undergoes a process of fundamental restructuring, horizontal market power appears as a potential obstacle to a fully competitive wholesale electricity market. Market power is the ability profitably to maintain prices above competitive levels by restricting output below competitive levels. In models for imperfect competition under the consideration of the transmission constraints, the Nash equilibrium has the form of a mixed strategy. In this paper, the models for analyzing imperfect competition are compared using the solution of pure and mixed equilibria. The relation between market power and the capacity of a transmission line is investigated by imperfect competition analysis methods: Cournot, Bertrand, and Supply Curve model.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.395-406
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• 2023

Ten women in their 20s and 10 women in their 50s were selected to investigate the effect of an elastic band exercise program for 8 weeks according to age on women's knee speed expression rate and balance. Knee isokinetic muscle strength measurement, single-legged standing with eyes closed, and YBT were performed 1 week before and after the exercise program. The measured data were analyzed through a mixed design two-way ANOVA, and if there was a significant difference, post hoc verification was performed using the bonferoni method. In our study, as a result of an 8-week elastic band exercise program, there was no difference in the speed development rate according to the measurement period, and the speed development rate according to age was found to be higher in people in their 50s than in their 20s. In our study, there was no difference in balance ability depending on the measurement period, and there was also no difference in balance ability depending on age. Discussing the results of our study, we found that 8 weeks of elastic band exercise cannot bring about significant changes in speed development ability and balance ability, which become more accurate with age.

• Kyungpook Mathematical Journal
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• 제53권4호
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• pp.647-660
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• 2013

In the paper, a two-prey one-predator system with defensive ability and Holling type-II functional responses is investigated. First, the stability of equilibrium points of the system is discussed and then conditions for the persistence of the system are established according to the existence of limit cycles. Numerical examples are illustrated to attest to our mathematical results. Finally, via bifurcation diagrams, various dynamic behaviors including chaotic phenomena are demonstrated.

• 한국자동차공학회논문집
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• 제10권1호
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• pp.84-92
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• 2002

On the cold start of LPG engine, as the engine temperature has not reached its equilibrium temperature, liquid LPG could not be changed perfectly gaseous LPG, although it was passed to the vaporizer. Liquid and gas mixed fuel could influence starting ability and exhaust emission characteristics of LPG engine. In this study, the vaporization characteristic of liquid LPG was investigated with a conventional vaporizer and the vaporizer with heat source(glow plug) installed at preheated chamber inlet, by using the visualization methods and engine test. According to visualization result, even if the engine coolant temperature was $14^{\circ}C$, liquid fuel was supplied to primary chamber over 25 seconds without vaporizing from preheated chamber in such a conventional vaporizer. However, the vaporizer with heat source do not correspond with that, scarcely had been trim on glow plug when LPG began to vaporize. The effectiveness of heat source could be verified by application to the conventional LPG engine.

• Environmental Analysis Health and Toxicology
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• 제6권3_4호
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• pp.143-148
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• 1991

This study was carried out to develop the low-priced adsorbent by synthesizing the zeolite of high cation exchange capacity with the natural zeolite and to examine the adsorbing ability of this zeolite. The dominant clay minerals were clinoptilolite and mordenite in natural zeolite, while phillipsite in the synthesized zeolite. Adsorption reaction of $NH_4^{+}$on zeolite was reached equilibrium after 2 hrs. The amount of adsorption was increased with increasing the concentration of $NH_4^{+}$or the pH of suspension. The cation exchange capacity of zeolite was slightly decreased below pH 4.0 by acidic treatment. It was estimated that the ability of the synthesized zeolite to remove noxious ions was better than that of the natural zeolite.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1279-1284
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• 2014

The binding of TATA-binding protein (TBP) to the TATA-box containing promoter region is aided by many other transcriptional factors including TFIIA and TFIIB. The mechanistic insight into the assembly of RNA polymerase II preinitation complex (PIC) has been gained by either directly altering a function of target protein or perturbing molecular interactions using drugs, RNAi, or aptamers. Aptamers have been found particularly useful for studying a role of a subset of PIC on transcription for their ability to inhibit specific molecular interactions. One major hurdle to the wide use of aptamers as specific inhibitors arises from the difficulty with traditional assays to validate and determine specificity, affinity, and binding epitopes for aptamers against targets. Here, using a technique called the bio-layer interferometry (BLI) designed for a label-free, real-time, and multiplexed detection of molecular interactions, we studied the assembly of a subset of PIC, TBP binding to TATA DNA, and two distinct classes of aptamers against TPB in regard to their ability to inhibit TBP binding to TFIIA or TATA DNA. Using BLI, we measured not only equilibrium binding constants ($K_D$), which were overall in close agreement with those obtained by electrophoretic mobility shift assay, but also kinetic constants of binding ($k_{on}$ and $k_{off}$), differentiating aptamers of comparable KDs by their difference in binding kinetics. The assay developed in this study can readily be adopted for high throughput validation of candidate aptamers for specificity, affinity, and epitopes, providing both equilibrium and kinetic information for aptamer interaction with targets.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제25권4호
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• pp.681-691
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• 2011

2009 개정 교육과정에 따른 수학과 교육과정에서 학교 수학은 학생들의 창의적 사고 능력과 더불어 수학에 대한 흥미와 호기심을 길러주고, 주변의 여러 가지 현상을 수학적으로 관찰하고 해석하는 능력과 태도를 길러야 한다고 제시한다. 2007 개정 교육과정에서 삼각형의 무게중심은 '삼각형의 세 중선의 교점'으로 정의되고, 평행선의 성질과 삼각형의 닮음을 이용한 증명에 초점을 두어 지도되었다. 이는 무게중심 그 자체에 초점을 두고 지도되지 못하였을 뿐 아니라 학생들에게 오개념 역시 심어줄 수 있는 문제점이 노출됨에 따라 본고에서는 무게중심을 '평형을 이루는 점'이라고 하는 본질에 맞게 지도하고 이에 대한 정당화 방법 역시 달리 할 수 있음을 제안한다.