• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.333-340
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• 2010

This paper presents the distributions of the tensile and fracture properties of an alloy 82/182 dissimilar weld joint between an SA508 Gr.3 nozzle and F316L SS safe-end at ambient temperature. Tensile and J-R tests were conducted using specimens extracted from base metals, heat-affected zones (HAZs), buttering regions, and various regions of the weld metal. The results show that the root region of the weld has higher strength than the upper region. The yield and tensile strengths vary considerably within the root region of the weld. The buttering region had the lowest strengths. The strengths gradually increased as the F316L stainless steel weld boundary was approached. The variation of the strengths within the upper region of the weld is insignificant. The fracture toughness of the alloy 82/182 weld metal is less than those of both the base metals and both HAZs. Within the alloy 82/182 weld, the center of weld has a slightly lower fracture toughness than the weld boundary and buttering region, and the root region has greater toughness than the upper region of the weld.

• Journal of The Korean Association For Science Education
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• v.35 no.1
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• pp.121-130
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• 2015

Identifying students' achievement level and reflecting it on educational policy making or instructional improvement by analyzing the results of nationwide standardized assessment is an integral part of accountability in education. On the basis of this premise, we analyzed the characteristics of National Assessment of Educational Achievement (NAEA) items for middle school science subject conducted from 2010 to 2013 by using the option response rate distribution curve, the fittest graph estimated from the response rate of correct/incorrect options by achievement score. Furthermore, we classified the type of option response rate curve in terms of correct and incorrect options. Results of the analysis of option response curve showed that five types of correct option response curve (S-shaped, J-shaped, straight-shaped, F-shaped, and step-shaped) and 4 types of incorrect option response curve (down-slope, flat, mound, and up-slope) were identified. The most common type of items was the combination of S-shaped correct option response curve and down-slope incorrect option response curve, which are considered as appropriate items to discriminate the students according to achievement level. Moreover, correct option response was found to be correlated with incorrect option response. Based on the results, we also discussed some implications on teaching-learning method and classroom assessment in science education.

• Journal of the Korean Vacuum Society
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• v.19 no.2
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• pp.81-90
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• 2010

We introduce a novel and versatile approach for preparing self-assembled nanoporous multilayered films with antireflective properties. Protonated polystyrene-block-poly (4-vinylpyrine) (PS-b-P4VP) and anionic polystyrene-block-poly (acrylic acid) (PS-b-PAA) block copolymer micelles (BCM) were used as building blocks for the layer-by-layer assembly of BCM multilayer films. BCM film growth is governed by electrostatic and hydrogen-bonding interactions between the oppositely BCMs. Both film porosity and film thickness are dependent upon the charge density of the micelles, with the porosity of the film controlled by the solution pH and the molecular weight (Mw) of the constituents. PS7K-b-P4VP28K/PS2K-b-PAA8K films prepared at pH 4 (for PS7K-b-P4VP28K) and pH 6 (for PS2K-b-PAA8K) are highly nanoporous and antireflective. In contrast, PS7K-b-P4VP28K/PS2K-b-PAA8K films assembled at pH 4/4 show a relatively dense surface morphology due to the decreased charge density of PS2K-b-PAA8K. Films formed from BCMs with increased PS block and decreased hydrophilic block (P4VP or PAA) size (e.g., PS36K-b-P4VP12K/PS16K-b-PAA4K at pH 4/4) were also nanoporous. Furthermore, we demonstrate that the nanostructured electrochemical sensors based on patterning methods show the electrochemical activities. Anionic poly(styrene sulfonate) (PSS) layers were selectively and uniformly deposited onto the catalase (CAT)-coated surface using the micro-contact printing method. The pH-induced charge reversal of catalase can provide the selective deposition of consecutive PE multilayers onto patterned PSS layers by causing the electrostatic repulsion between next PE layer and catalase. Based on this patterning method, the hybrid patterned multilayers composed of platinum nanoparticles (PtNP) and catalase were prepared and then their electrochemical properties were investigated from sensing $H_2O_2$ and NO gas. This study was based on the papers reported by our group. (J. Am. Chem. Soc. 128, 9935 (2006); Adv. Mater. 19, 4364 (2007); Electro. Mater. Lett. 3, 163 (2007)).

• Journal of the Korean Vacuum Society
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• v.19 no.4
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• pp.243-248
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• 2010

Sonic nozzles have been a standard device for measurement of steady state gas flow, as recommended in ISO 9300. This paper introduces two sonic nozzles of diameter ${\Phi}$ 0.03 mm and ${\Phi}$ 0.2 mm precisely machined according to ISO 9300. The constant volume flow meter(CVFM), readily set up in the Vacuum center of KRISS. was used to calibrate the discharge coefficients of both nozzles. The calibration results were shown to determine them within the 3% expanded measurement uncertainty. Calibrated sonic nozzles were found to be applicable for precision measurement of steady state gas flow in the vacuum process in the ranges of 0.6~1,800 cc/min. Those flow conditions are equivalent to the fine gas flow with Reynolds numbers of 26~12,100. Those encouraging results confirm that calibrated sonic nozzles enable precision measurement of extremely low gas flow encountered very often in th vacuum processes. Both calibrated sonic nozzles are proven to provide the precision measurement of the volume flow rate of the dry vacuum pump within one percent difference in reference to CVFM. Calibrated sonic nozzles are applied to a new 'in-situ and in-field' equipment designed to measure the volume flow rate of vacuum pumps in the semiconductor and flat display processes. Furthermore, they can provide other applications to flow control devices in vacuum, such as MFC, etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1732-1739
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• 2011

This study aims to make a comparison of educational effectiveness between instructor-centered learning and video self-instruction(VSI) about automatic external defibrillator(AED) for high school girls in order to help select an effective teaching method concerning AED. A total of 59 high school girls (29 for the experimental group, 30 for the control group) in J Province participated in this study from July 7 to 14, 2010. The analysis was carried out by using an SPSS WIN 12.0 Version program. After the AED instruction, the knowledge increased more in the experimental group (1.72) than that in the control group (1.60); self-confidence increased more in the experimental group (1.58) than that in the control group (1.46); and accuracy of technical performance increased more in the control group (5.46) than that in the experimental group (4.20). The experimental group (5.68) was more satisfied with AED instruction than the control group (4.95). Since video self-instruction proved to be more educationally effective than instructor-centered learning in most areas, it is necessary to apply video self-instruction to AED instruction in the future. However, further researches are necessary to see if video self-instruction is effective.

• Journal of Sasang Constitutional Medicine
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• v.25 no.3
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• pp.167-179
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• 2013

Objectives This study was performed to compare responses of Korean to the Sasang Constitution questionnaire with those of Japanese and to learn difference in characteristic according to the Sasang Constitution between two countries. Methods 301 Korean visiting the department of the Sasang Constitution, Dong-Eui Medical Center in Busan, Korea from November 2006 to September 2010 responded to the SSCQ-P(Sasang Constitution Questionnaire for Patients). Sasang Constitution specialist interviewed subjects and diagnosed their Sasang Constitution. 361 Japanese visiting the center for Kampo Medicine, Keio University in Tokyo, Japan from January 2010 to February 2011 responded the SSCQ-J(Sasang Constitution Questionnaire for Japanese). The Sasang Constitution was diagnosed in the same way as Korean. We compare responses to the SSCQ-P in Korean with those to the SSCQ-J in Japanese. Results 1. Among Soyangin related 58 items of Sasang Constitution questionnaire, 26, 46.36% items had statistically significant response results in both Korean and Japanese and response disposition of all these items was same. Among Taeeumin related 68items, 36, 52.94% items had statistically significant response results in both Korean and Japanese. Of these, response disposition of 35 items was same and that of 1 item was different. Among Soeumin related 71 items, 31, 43.66% items had statistically significant response results in both Korean and Japanese. Of these, response disposition of 28 items was same and that of 3 items was different. 2. The proportion of items having statistical significance and same disposition in both Korean and Japanese by Sasang Constitutional characteristic category[Features and Way of Speaking, Physical Appearance, Temperament and Talent, Pathological Syndromes] was as follows; In Soyangin, the proportion in Pathological Syndromes was 27.8% and that in the others was more than 41.7%. In Taeeumin, the proportion in Pathological Syndromes was 33.3% and that in the others was more than 57.9%. In Soeumin, the proportion in Features and Way of Speaking was 70.6%, that in Physical Appearance was 8.3% and that in the others was 30~40%. Conclusions The response disposition of many of items having statistical significance between Korean and Japanese was same and that of a few was different. From this, there are many common Sasang Constitutional characteristics between two countries, and possibility of applying the Sasang Constitutional Medicine of Korea to Japan.

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.23-32
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• 2012

This study was conducted to monitor microbial species dynamics within the aquifer due to long term operation of geothermal heat pump system. The species were identified by molecular biological methods of 16S rDNA. Groundwater sample was collected from both open (S region) and closed geothermal recovery system (J region) along with the control. J measured and control as well as S measured found Ralstonia pickettii as dominant species at year 2010. In contrast, Rhodoferax ferrireducens was dominantly observed for the control of S. In 2011, Sediminibacterium sp. was universely identified as the dominant species regardless of the monitoring places and type of sample, i.e., measured or control. The difference in the dynamics between the measured and the control was not critically observed, but annual variation was more strikingly found. It reveals that possible environmental changes (e.g. ORP and DO) due to the operation of geothermal heat recovery system in aquifer could be more exceedingly preceded to differentiate annual variation of microbial species rather than positional differences.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.172.2-172.2
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• 2010

This study was carried out in order to reduce the installation expense of heating system for greenhouse comparing to geothermal heat pump and develope the coefficient of performance (COP) for a heat pump. For getting plenty of heat flux from geothermal energy. Surface water in river channel was used for getting a lots of geothermal heat by penetrating water through underground soil layer of the river bank that make heat transmission to passing water. The range of water temperature after the process of Ground filtration is 13~18 degrees celsius which is very similar to low heat source of geothermal heat pump system and the plenty amount of heat source from that make the number of geothermal heat exchanging hole and the expense for geothermal heat exchanger construction reduced. Drainage well is also used for returning filtration water to the aquifer that keep the water good recirculation from losing geothermal heat and water resource. For the COP improvement of Heat pump, thermal storage tank with separating insulation plate according to the temperature difference make the COP of Heat pump that is similar to thermal storage tank with diffuser. Developed thermal storage tank make construction expense cheaper than customarily used one's. and that sand filter and oxidation sand (FELOX) are going to be used for improving ground filtration water quality that make heat exchanger efficiency better. All above developed component skill are going to be set on the Ground filtration water source heat pump system and applied for medium, large scale for protected greenhouse in riverside area and on-site experiment is going to do for optimizing the heating system function and overcome the problem happening in the process of on-site application afterward.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.72.2-72.2
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• 2010

평판형 고체산화물 연료전지 스택의 고온 밀봉 구조에 대하여 설명하고 스택 운전 후 사후 분석을 통하여 밀봉재와 금속 분리판의 계면반응에 대하여 고찰하였다. 대표적인 고온 밀봉재인 Barium-Silicate 계 결정화 유리와 Fe-Cr 계 금속 분리판은 스택의 작동온도인 $700{\sim}850^{\circ}C$ 에서 고온 반응을 통하여 계면에 반응생성물을 형성하는 것이 확인되었다. 이러한 계면반응은 장기 운전시 SOFC 스택 성능 저하의 원인이 되고, 열 싸이클(작동온도${\leftrightarrow}$상온)을 가하면 계면반응 생성물이 delamination 되어 밀봉구조가 파괴되어 수명을 단축시키게 된다. 계면반응은 Fe-Cr 계 금속 분리판의 산화물인 Cr 산화물, Fe 산화물이 밀봉유리 소재와 반응을 일으키는 것이 주요 원인으로 판명되었다. SOFC 스택에서 열 싸이클시 계면반응에 의하여 기밀도가 감소하는 현상이 확인되었으며, 밀봉 구조의 어느 부분에서 계면반응이 진행되는지 관찰하였다. 이러한 계면반응을 막기 위해서는 금속 분리판과 밀봉유리 사이에 계면반응을 억제하는 보호층을 형성하는 방법이 효과적이다. 본 연구에서는 보호층으로서 밀봉유리 및 Fe-Cr 계 금속 분리판과의 계면반응성이 낮고 열팽창 계수가 비슷한 Yttria Stabilized Zirconia 층을 APS(Atmospheric Plasma Spray) 공정을 이용하여 형성하였다. 밀봉유리/YSZ 보호층/금속분리판은 gas-tight 한 밀봉 구조를 형성하였으며, YSZ 보호층은 밀봉유리와 Fe-Cr 계 금속 분리판 소재와 계면반응을 효과적으로 억제하는 것이 확인되었다.

• Biomedical Science Letters
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• v.16 no.3
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• pp.151-159
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• 2010

The peroxisome proliferator-activated receptor $\alpha$ (PPAR$\alpha$) is a nuclear transcription factor that plays a central role in lipid metabolism and obesity. Exercise also is a powerful modifier of the manifestations of the lipid metabolism and obesity in animal models and humans with obesity and metabolic syndrome. However, effects of exercise on lipid metabolism and obesity in normal-weight younger female subjects, having functional ovaries and not metabolic disease, remain unexplained. To explore the effects of exercise on the development of obesity and its molecular mechanism in high fat diet-fed female C57BL/6J mice, we experimented the effects of swim training on body weight, adipose tissue mass, serum lipid levels, morphological changes of adipocytes and the expression of PPAR$\alpha$ target genes involved in fat oxidation in skeletal muscle tissue of female C57BL/6J mice. Swim-trained mice had significantly decreased body weight, adipose tissue mass, serum triglycerides compared with female control mice. Histological studies showed that swim training significantly decreased the average size of adipoctyes in parametrial adipose tissue. Swim training did not affect the expression of PPAR$\alpha$ mRNA in skeletal muscle. Concomitantly, swim training did not increase mRNA levels of PPAR$\alpha$ target genes responsible for fatty acid $\beta$-oxidation, such as carnitine palmitoyltransferase 1, medium chain acyl-CoA dehydrogenase, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase, and thiolase in skeletal muscle. In conclusion, these results indicate that swim training regulates lipid metabolism and obesity in high fat diet fed-female mice although swim training did not increase mRNA levels of PPAR$\alpha$ target genes involved in fatty acid $\beta$-oxidation in skeletal muscle, suggesting that swim training may prevent obesity and improve fitness through other mechanisms in female with ovaries, not through the activation of skeletal muscle PPAR$\alpha$.