• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.10
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• pp.893-899
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• 2010

A previous study showed that hemodynamics is correlated with stenosis in the coronary artery. The flow characteristics and the distributions of the hemodynamic wall parameters in the coronary artery are investigated under physiological flow condition. The present study also aims to establish the mechanism of the generation of atherosclerosis by analyzing the hemodynamic variables in the coronary artery where atherosclerosis frequently occurs. The stenosis phenomena due to atherosclerosis are related to not only the biochemical reaction between blood and blood vessels but also the hemodynamic factors sush as flow separation and oscillatory wall shear stress. As the bifurcated angle increases, the size of the recirculation area that appears in the cross section increases and disturbed flow is observed in this area. We speculate that this area is the starting point of atherosclerosis in the coronary artery.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.325-330
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• 1996

Dynamic parameters of physiology including embryo ratio (ER), embryo length to endosperm length, dry weight ratio between embryo and endosperm (DWR) and respiration rate (RR) in American send (Panax quinquefolium L.) seed were investigated. According to the changes of ER during seed stratification, the duration of embryo afterripening could be divided into three stages as \circled1 embryo slow growth stage (ESGS), ER increased from 7.31% to 20.48% (0.16% day-1): \circled2 embryo rapid growth stage (ERGS), ER increased to 80.98% (0.61% day-1) (75G5+ ERGS=morphological afterripening stage (MP,5)) and \circled3pysiological afterripening stage (PAS), ER Increased to 88.50% (0.094 day-1) only. DWR Increased slowly from 0.20% to 2.76clp (0.016% day-1) in MAS and rapidly to 8.81% (0.061% day-1) in PAS. The RR correlated significantly with ER as well (r=0.8934 > rot, 0.6610). The steep increment of both DWR and RR in PAS indicated that the PAS was not a static stage although the ER was not changed too much. All of these may provide some information for understanding the dormancy mechanisms of American sting seed.

• Journal of the Korean Chemical Society
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• v.21 no.1
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• pp.38-43
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• 1977

The rate constant of the reaction of 3-or 4-substituted pyridines with benzyl benzenesulfonate in acetone at $35^{\circ}C$ were determined by an electric conductivity method. According to the Hammett plot, the rates were increased the electron donating ability at the $S_N2$ reaction of benzyl benzenesulfonate with pyridine and 4-$NH_2$ pyridine was correlated with ${\sigma}^+$ than Hammett ${\sigma}$ value. This result was explained that $NH_2$ group and N atom in pyridine are largely contribute by resonance. In Br$\"{o}$nsted plot, 4-amino and electron attracting group were deviated from the increasing part at linearity. It was considered to solvent effects on substituents. A mechanistic possibility was proposed to account for the results. Some activation parameters were also calculated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.746-752
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• 2017

High test hydrogen peroxide has been widely developed as green propellant for thrusters. Hydrogen peroxide is decomposed in the catalyst bed to produce the thrust. Catalyst bed design optimization is considered through existing model for catalyst beds. To verify the model, static firing tests were conducted under various conditions using a 100 N scale $H_2O_2$ monopropellant thruster. Temperature and pressure estimations from the model were well correlated to the experimental data. The model is used to obtain optimal design parameters by analyzing the catalyst capacity and pressure drop data for various simulated conditions. Catalyst beds can be optimized from the analysis of the catalyst capacity and pressure drop correlation through catalyst bed modeling.

• Journal of the Korean Home Economics Association
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• v.38 no.12
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• pp.59-71
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• 2000

The purpose of this study was to assess the iron nutritional status and dietary iron availability of postmenopausal women residing in Jeonju area. The anthropometric parameters, nutrient intake and biochemical status of iron were measured from 57 postmenopausal women aged 50∼74 years old. Mean values of hemoglobin(Hb), hematocrit(Hct), serum iron(Fe), total iron binding capacity(TIBC) and serum ferritin(Ferritin) concentration were 12.82${\pm}$1.03g/dl, 37.68${\pm}$2.99%, 92.60${\pm}$46.66ug/dl, 353.0${\pm}$54.48ug/dl, 86.86${\pm}$100.7ug/ιrespectively. Prevalence of iron deficiency greatly varied by indices from 14.04% when judged by Ferritin(<20ug/ι) to 40.4% by TIBC(>360${\mu}$g/dl. The anemic subjects assessed with Hct percent(36%) represented 22.8%, whereas 21.1% of the subjects possessed less than 12g/dl of Hb. Ferritin concentration showed a significantly negative correlation with TIBC(r=-0.343, p<0.01) and a positive correlation with MCHC(r=0.361, p<0.01). The mean daily intake of iron was 10.62mg and intake of heme iron was 5.3%(0.56mg) of total iron intake. Total absorbable iron caculated by the method of Monsen was 0.49mg anti bioavailability of dietary iron was 4.61%. Ferritin Concentration was positively associated with total iron intake(r=0.264, p<0.05), dietary nonheme iron(r=0.286, p<0.05) and iron of animal food (r=0.364, p<0.01). But Ferritin concentration was not correlated dietary heme iron(r=-0.137, p>0.05). Major food groups of iron intake were vegetables(20.15%), cereals(19.59%) and fishes(12.34%) in postmenopausal women. Intake of eggs was positively associated with Ferritin(r=0.473, p<0.01).

• Korean Journal of Psychosomatic Medicine
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• v.3 no.2
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• pp.147-158
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• 1995

This paper describes the development of Korean version of two widely used self-report measure of alexithymia-Schalling-Sifneos Personality Scale (SSPS) and Toronto Alexithymia Scale(TAS), and present the preliminary results of their reliability and validity tested to an Korean college student sample(N=206). TAS showed moderate to acceptable internal consistancy with 0.26 of mean item-total correlation and 0.754 of Cronbach's alpha coefficient, while those parameters for SSPS turned out inconsistent. However, results of test-retest reliability for both scale were excellent. Factor analysis revealed tow factors for TAS and three factors for SSPS ; the four-factor structure of TAS was quite congruent with previously known alexithymaia construct, while, again, SSPS showed intermixed factor structure. TAS scores correlated fairly well with somatization scores enough to get concurrent validity while SSPS scores did not. Overall, Korean version of TAS demonstrated well matched findings in terms of internal consistency and factorial validity with original and Spanish version of TAS. The results suggest that Korean version of TAS could be a useful and reliable tool for the measurement in Korean population.

• Journal of Surface Science and Engineering
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• v.49 no.1
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• pp.40-45
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• 2016

Recently, $Bi_2Te_3$-based alloys are the best thermoelectric materials near to room temperature, so it has been researched to achieve increased figure of merit(ZT). Ternary compounds such as Bi-Te-Se and Bi-Sb-Te have higher thermoelectric property than binary compound Bi-Te and Sb-Te, respectively. Compared to DC plating method, pulsed electrodeposition is able to control parameters including average current density, and on/off pulse time etc. Thereby the morphology and properties of the films can be improved. In this study, we electrodeposited n-type ternary Cu-doped $Bi_2(Te-Se)_3$ thin film by modified pulse technique at room temperature. To further enhance thermoelectric properties of $Bi_2(Te-Se)_3$ thin film, we optimized Cu doping concentration in $Bi_2(Te-Se)_3$ thin film and correlated it to electrical and thermoelectric properties. Thus, the crystal, electrical, and thermoelectric properties of electrodeposited $Bi_2(Te-Se)_3$ thin film were characterized the XRD, SEM, EDS, Seebeck measurement, and Hall effect measurement, respectively. As a result, the thermoelectric properties of Cu-doped $Bi_2(Te-Se)_3$ thin films were observed that the Seebeck coefficient is $-101.2{\mu}V/K$ and the power factor is $1412.6{\mu}W/mK^2$ at 10 mg of Cu weight. The power factor of Cu-doped $Bi_2(Te-Se)_3$ thin film is 1.4 times higher than undoped $Bi_2(Te-Se)_3$ thin film.

• Journal of Soil and Groundwater Environment
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• v.8 no.1
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• pp.81-86
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• 2003

Understanding the penetration behavior of the spilled oil is very important to remove itself and to minimize its impact on intertidal biological communities by earlier treatment of the oil. The purpose of this study is to clarify the effects of wave and tidal actions on the penetration of spilled oil and to evaluate main factors of oil penetration using a sandy-beach model. Infiltration processes into the sediments showed significant difference between seawater and crude oil. Seawater was infiltrated by both wave action and tidal fluctuation into the sediments in sandy beach. However, spilled crude oil penetrated into the sediments only by falling tides and not by wave action, and the first tide is most important for the penetration of stranded oil. Over 70% of bulk fraction in penetrated crude oil was concentrated to the top 2 cm sediment-layer when spilled oil volume was 1 L/$\textrm{m}^2$. Moreover, the penetration of stranded oil into the sandy beach sediments was strongly correlated with the oil viscosity affected by temperature.

• Journal of Photoscience
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• v.12 no.1
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• pp.33-39
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• 2005

Plants possess the ability to dissipate the excitation energy for the protection of photosynthetic apparatus from absorbed excess light. Heat dissipation is regulated by xanthophyll cycle in thylakoid membranes of chloroplasts. We investigated the mechanistic aspects of xanthophyll cycle-dependent photoprotection against low-temperature photoinhibition in plants. Using barley and rice as chilling-resistant species and sensitive ones, respectively, chilling-induced chlorophyll fluorescence quenching, composition of xanthophyll cycle pigments and mRNA expression of the zeaxanthin epoxidase were examined. Chilled barley plants exhibited little changes in chlorophyll fluorescence quenching either of photochemical or non-photochemical nature and in the photosynthetic electron transport, indicating low reduction state of PS II primary electron acceptor. In contrast to the barley, chilled rice showed a marked decline in those parameters mentioned above, indicating the increased reduction state of PS II primary electron acceptor. In addition, barley plants were shown to have a higher capacity to elevate the pool size of xanthophyll cycle pigments in response to cold stress compared to rice plants. Such species-dependent regulation of xanthophyll cycle activity was correlated with the gene expression level of cold-induced zeaxanthin epoxidase. Chilled rice plants depressed the gene expression of zeaxanthin epoxidase, whereas barley increased its expression in response to cold stress. We suggest that chilling-induced alterations in the pool size of xanthophyll cycle pigments related to its capacity would play an important role in regulating plant's sensitivity to chilling stress.

• Korean Journal of Head & Neck Oncology
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• v.21 no.1
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• pp.15-20
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• 2005

Objectives: The hepatocyte growth factor(HGF)/c-Met pathway may play various roles in the carcinogenesis of various organs. Although HGF/c-Met signalling pathway has been shown to demonstrate various cellular responses including mitogenic, proliferative, morphogenic and angiogenic activities, the study on their expression related to clinicopathological parameters in thyroid tumor is relatively rare. So we want to find out the clinical significance of the c-Met in thyroid tumor. Materials and Methods: We assess the mRNA and protein expression of the c-Met genes by means of RT-PCR method and the immunohistochemical stain in 100 cases of thyroid tumors(50 papillary carcinomas, 10 follicular carcinomas, 20 follicular adenomas, 20 nodular hyperplasia). Results: By RT-PCR, c-Met mRNA was detected in 43(86%) in papillary carcinoma, 4(40%) in follicular carcinoma, 4(20%) in follicular adenoma and 2(10%) in nodular hyperplasia cases. By immunohistochemistry, c-Met protein expression was detected in 44(88%), 2(20%), 3(15%) and 1(5%). Expression of the c-Met mRNA and protein expression was significantly highly recognized in papillary carcinoma. The c-Met protein overexpression was significantly correlated with the grade of the differentiation. Conclusion: These results suggest that c-Met expression may be associated with thyroid papillary cancer progression. The differential expression of c-Met protein and mRNA suggests that these molecules may be a reliable diagnostic marker in thyroid papillary cancer.