• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.346-346
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• 2007

압전세라믹 재료는 현재 압전 변압기, actuator, transducer, sensor, speaker 등에 광범위하게 이용이 되고 있다. 이 중에서 압전세라믹 소결체를 이용한 스피커의 제조는 가공이 까다롭고, 대형의 크기로 제작 시 소자가 깨지는 등의 많은 제약을 받고 있으며, 저음 특성이 떨어져 응용 범위가 한정되어 있다. 따라서 최근에는 이러한 단점을 극복하기 위하여 세라믹/고분자 복합체를 이용한 필름 스피커를 제작하고자 시도하고 있다. 이러한 세라믹/고분자 0-3형 압전 복합체를 이용할 경우, 제품의 경량화를 실현할 수 있고, 크기나 환경의 영향을 거의 받지 않으므로, 고기능성 스피커로의 응용에 적합할 것으로 보인다. 따라서 본 연구에서는 PZT계의 세라믹와 PVDF, PVDF-TrFE, Polyester, acrylic resin 등의 여러 고분자 물질과의 복합체를 제조하여 압전특성을 평가하였다. 본 실험은 먼저 $(Pb_{1-a-b}Ba_aCd_b)(Zr_xTi_{1-x})_{1-c-d}(Ni_{1/3}Nb_{2/3})_c(Zn_{1/3}Nb_{2/3})_dO_3$ (이하 PZT라 표기)의 최적화 조성을 선택하여, $1050^{\circ}C$에서 소결된 분말을 48시간 ball milling방법 로 약 $1{\mu}m$ 크기로 분쇄하였다. 고분자 물질들은 알맞은 용제들을 선택하여 녹였다. 그 다음 소결된 PZT분말과 고분자를 50:50, 60:40, 65:35, 70:30등의 무게 분율로 혼합하고, 분산제, 소포제 등을 첨가하여 3단 roll mill을 이용하여 충분히 분산시켜 페이스트 (Paste)를 제조하였다. 제조된 페이스트를 ITO가 코팅된 PET필름 위에 스크린 프린팅 법을 사용하여 인쇄하여 $120^{\circ}C$에서 5분간 건조하였다. 코팅된 복합체의 두께는 약 $80{\mu}m$ 정도로 측정되었다. Ag 페이스트를 이용한 상부 전극 형성에도 스크린 프린팅 법을 적용하였다. 이를 $120^{\circ}C$에서 4 kV/mm의 DC 전계로 분극 공정을 수행한 후 전기적 특성을 평가하였다. 유전특성을 조사하기 위해서 LCR meter (EDC-1620)를 사용하였고, 시편의 결정구조는 XRD (Rigaku; D/MAX-2500H)을 통해 분석하였으며, 전자현미경(SEM)을 이용하여 미세구조를 분석하였다. 압전 전하상수$(d_{33})$ 값은 APC 8000 모델을 이용하여 측정하였다. PZT의 혼합비가 증가할수록 비유전율 및 압전 전하 상수 등의 전기적 특성이 증가되었다. 또 여러 고분자 물질 중에서 PVDF-TrFE 수지가 가장 우수한 특성을 보였다. 이는 PVDF-TrFE 수지가 압전성을 나타내기 때문인 것으로 판단되었다.

• Journal of Nutrition and Health
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• v.41 no.7
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• pp.634-664
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• 2008

This study investigated the effects of the nutrition education on body weight, visceral fat and diet quality in the postmenopausal women. The subjects (n = 101) were randomly divided into two groups: Nutrition education + Exercise (NEE) group (n = 51) and Exercise only (EO) group (n = 50). Nutrition education was consisted of counseling in portion control, food selection for low carbohydrate, high fiber food items and for the improvement in micronutrient intakes and diet quality. After 6 months, the reduction in the body weight and visceral fat area was significantly greater in the NEE than in the EO group. The NEE subjects were further divided into two groups according to the amount of visceral fat area reduction; high visceral fat area loss (HVL) group with a visceral fat area reduction 2.35% or greater and low visceral fat area loss (LVL) group with a reduction less than 2.35%. In the HVL group, the reduction in body weight, BMI, percent body fat, waist to hip ratio and visceral fat area was significantly greater than that in the LVL group. We observed a significant increase in the serum HDL-cholesterol level and a decrease in systolic blood pressure, fasting blood sucrose, total and LDL-cholesterol levels in the HVL group compared to the LVL group. The energyadjusted protein, fiber, calcium, vitamin $B_6$, vitamin C, vitamin E intakes were significantly increased in the HVL compared to LVL group. The index of nutritional quality (INQ) and mean adequacy ratio (MAR) were also increased in the HVL group compared to the LVL group. These results show that our nutrition education program was an effective intervention measure for the reduction of body weight and visceral fat, blood pressure, glucose and lipid levels in the blood and also for the improvement of nutrient intake and diet quality in postmenopausal women who are overweight.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1703-1708
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• 2004

This study was carried out to investigate the characteristic quality of jeungpyun added Paecilomyces japonica with different fermentation time. The volume of jeungpyun added Paecilomyces japonica was more increased after fermentation. The volume was decreased when the fermentation was progressed. The pH was 5.1 before fermentation and the pH decreased when the fermentation was progressed. Moisture content was more increased as the time of fermentation became longer. Hunter color test, L value and b value appeared the highest after 1st fermentation, and it appeared lesser when the time of fermentation became longer. In measurement of texture, hardness showed the highest value when 90 minutes passed after the 2nd fermentation. Gumminess and brittleness were tend to increase when it have longer fermentation time. In scanning electron microscopic observation, organization of sponges was tend to break down as the fermentation time was longer. Sensory properties showed that color intensity was more strong when second fermentation was progressed, and hardness, toughness, sourness were high when the fermentation time was longer. In conclusion overall acceptability of jeungpyun, 3$0^{\circ}C$, 3 hours after 1st fermentation and 2nd fermentation for 30 minutes, 35$^{\circ}C$ showed the most preference.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.123-130
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• 2015

This study examines the effects of different types of bridge exercises on the thickness of trunk muscles through ultrasound fusion imaging on 32 students. The thickness of the internal oblique (IO), external oblique (EO), transverse abdominis (TrA), and multifidus (Mf) muscles were measured in three different bridge exercises. The exercises included a supine bridge exercise, which was performed on a fixed support surface (Exercise A), a gym ball bridge exercise (Exercise B), and a sling bridge exercise (Exercise C). There were significant differences among the three bridge exercises in the IO, TrA, and Mf muscles. The IO was thickest in Exercise B followed by Exercise A and C. In contrast, the TrA and the Mf muscles were thickest in Exercise C followed by Exercise A and B. Therefore, the sling bridge exercise may be a more effective method of enhancing trunk muscle thickness than the exercises performed in other positions. Until recently, no previous studies had observed substantial changes in muscle thickness using ultrasound fusion imaging. This study suggests that sling bridge exercises contribute most to the activation of trunk muscles. Therefore, the research can contribute to the prescription and application of bridge exercises in clinical practices.

• Korean Journal of Ecology and Environment
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• v.51 no.3
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• pp.221-233
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• 2018

This study was carried out to predict the current and future potential distribution and to identify the factors affecting potential distribution of 7 plants(Lamium amplexicaule L., Trigonotis peduncularis(Trevir.) Benth. ex Hemsl, Capsella bursa-pastoris (L.) L. W. Medicus, Taraxacum officinale Weber, Veronica persica Poir., Conyza sumatrensis E. Walker, Hypochaeris radicata L.) selected as indicators for climate change in agricultural ecosystem. We collected presence/absence data of 7 indicator plants at 108 sites in South Korea and applied the Maxent model. According to future climate scenario, the distribution area of C. bursa-pastoris(L.) L. W. Medicus, T. officinale Weber, and V. persica Poir. was expected to be reduced, but the distribution range was to be maintained. The distribution areas and range of the C. sumatrensis E. Walker and H. radicata L. were expected to be increased. The distribution area and range of T. peduncularis (Trevir.) Benth. Ex Hemsl. and L. amplexicalue L. were rapidly decreased. Non-climatic factors such as land cover and altitude were the most important environmental variable for T. officinale Weber, C. bursa-pastoris(L.) L.W.Medicus, V. persica Poir., T. peduncularis (Trevir.) Benth. Ex Hemsl., and L. amplexicalue L.. Climatic factors were the most important environmental variable for C. sumatrensis E. Walker and H. radicata L.. It is expected that the future potential distribution of 7 indicator plants response to climate change will be used to monitor and to establish the management plan.

• Journal of Conservation Science
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• v.31 no.1
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• pp.47-64
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• 2015

The excavated potteries and raw clays of the Bronze Age from the archaeological sites in the Cheonan-Asan area were studied on material scientific characteristics and homogeneity. Under the microscope, grainsize of the tempers in the potteries were distributed from less than 1mm to 10mm. Microtexture of the potteries showed various shapes and sizes of pores. In addition to the main minerals such as quartz, feldspar, mica, hornblende, chlorite and talc were found from the X-ray diffraction analysis of potteries, while talc was not found in the raw clay. Therefore, it was considered as an artificially added mineral. Firing temperature of the potteries, which did not contain chlorite, are assumed that they were baked below $850^{\circ}C$. On the other hand, the potteries which had mica and talc, are assumed that they were fired below $900^{\circ}C$. The geochemical characteristics of the potteries and raw clays showed very similar patterns, that means the potteries were produced by using the raw clay sources from each site.

• Korean Journal of Environmental Biology
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• v.40 no.1
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• pp.1-10
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• 2022

Global warming has a major impact on the Earth's precipitation and temperature fluctuations, and significantly affects the habitats and biodiversity of many species. Although the number of alien plants newly introduced in South Korea has recently increased due to the increasing frequency of international exchanges and climate change, studies on how climate change affects the distribution of these alien plants are lacking. This study predicts changes in the distribution of suitable habitats according to RCPs climate change scenarios using the current distribution of the invasive alien plant Conyza sumatrensis and bioclimatic variables. C. sumatrensis has a limited distribution in the southern part of South Korea. Isothermality (bio03), the max temperature of the warmest month (bio05), and the mean temperature of the driest quarter (bio09) were found to influence the distribution of C. sumatrensis. In the future, the suitable habitat for C. sumatrensis is projected to increase under RCP 4.5 and RCP 8.5 climate change scenarios. Changes in the distribution of alien plants can have a significant impact on the survival of native plants and cause ecosystem disturbance. Therefore, studies on changing distribution of invasive species according to climate change scenarios can provide useful information required to plan conservation strategies and restoration plans for various ecosystems.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.219-224
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• 2019

BACKGROUND: Soil bacteria play important roles in organic matter decomposition and nutrient cycling during the non-growing season. The purpose of this study was to investigate the effects of soil management and chemical properties on the utilization of carbon sources by soil bacteria in paddy fields. METHODS AND RESULTS: The Biolog EcoPlate was used for analyzing community-level carbon substrate utilization profiles of soil bacteria. Soils were collected from the following three types of areas: plain, interface and mountain areas, which were tested to investigate the topology effect. The results of canonical correspondence analysis and Kendall rank correlation analysis showed that soil C/N ratio and NH₄⁺ influenced utilization of carbon sources by bacteria. The utilization of carbohydrates and complex carbon sources were positively correlated with NH₄⁺ concentration. Cultivated paddy fields were compared with adjacent abandoned fields to investigate the impact of cultivation cessation. The level of utilization of putrescine was lower in abandoned fields than in cultivated fields. Monoculture fields were compared with double cropping fields cultivated with barley to investigate the impact of winter crop cultivation. Cropping system altered bacterial use of carbon sources, as reflected by the enhanced utilization of 2-hydroxy benzoic acid under monoculture conditions. CONCLUSION: These results show that soil use intensity and topological characteristics have a minimal impact on soil bacterial functioning in relation to carbon substrate utilization. Moreover, soil chemical properties were found to be important factors determining the physiological profile of the soil bacterial community in paddy fields.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.6
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• pp.707-716
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• 2006

To make tofu (soybean curd) with cuttlefish int the cuttlefish ink diluted 20-fold was added to soymilk in the ratio of 0%, 1%, 3%, 5%, 7% and 9% there is no respective comparison here respectively and the prepared cuttlefish inky tofu samples were stored for 15 days at $4^{\circ}C$. After storage, the tofu samples were tested for yield, pH, acidity, bacterial growth, sensory evaluations and physical properties. The yields of 7%(I7) and especially 9%(I9) cuttlefish ink tofu were higher than that of the control tofu(I0). The pH was decreased, but the acidity was increased with increasing storage period. The microorganism count of I9 was the lowest during the storage period. The turbidity gradually increased until 9 days of storage and rapidly increased at 12 days of storage. In the measurement of inky tofu color, the L and b values were decreased during the storage period. In the texture analysis, the hardness, gumminess and brittleness of inky tofu were increased until 12 days of storage but then decreased. Chewiness was decreased with increasing storage period. Springiness of Il and I3 was higher than that of I0. In sensory evaluation, color was increased with increasing cuttlefish inky concentration. Sleekness of I3 was the highest. Hardness and chewiness of inky Il and I3 were the highest. Springiness, cohesiveness and softness were the highest in I3. In overall acceptability, I3 gained the highest score.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.255-255
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• 2015

국제핵융합실험로(ITER)의 3대 목표 중 하나는 핵융합로 개발을 위한 삼중수소증식블랑켓 개념을 시험하고 검증하는 것이며, 이를 위해 시험증식블랑켓(TBM, Test Blanket Module) 프로그램을 마련, 각국이 참여할 수 있도록 하고 있다. 한국도 2012년 국가핵융합위원회 결정에 따라, EU, 일본, 중국, 인도와 함께 TBM 프로그램에 참여하고 있으며, 2021년 설치를 목표로 헬륨냉각 고체증식재 개념의 HCCR (Helilum Cooled Ceramic Reflector) TBM을 설계, 개발하고 있다. 한국형 TBM은 총 4개의 서브모듈과 하나의 후벽(Back Manifold, BM) 으로 구성되며, 각 서브모듈은 플라즈마와 대면하는 일차벽(First Wall, FW), 증식재와 증배재, 반사재를 담고 있는 증식영역(Breeding Zong, BZ), 냉각재 매니폴드 및 구조물 역할을 하는 측벽(Side Wall, SW) 등의 기능부품으로 구성되어 있다. 냉각재는 8 MPa, $300-500^{\circ}C$의 고온고압헬륨을 사용하고, Li2SiO4 혹은 Li2TiO4 형태의 Li 세라믹 증식재를 사용하며, 중성자 증배를 위해 Be 증배재 및 흑연 반사재를 사용한다 [1-3]. 2015년 2월 개념설계검토(CDR, Conceptual Design Review)를 위해, TBM-shield를 포함한 TBM-set 설계가 완료되었으며, 열수력, 구조, 지진, 전자기, 복합하중에 대한 평가가 진행되었다. 본 논문에서는 이 중 H/He-phase에 시험될 EM-TBM과 D-T phase에 시험될 INT-TBM에 대한 열수력 성능 결과를 소개하였다[5]. 각각의 열부하 조건은 0.17과 $0.3MW/m^2$이며, 중성자 조사는 D-T phase 에서만 고려되었다. 구조재 및 사용된 기능소재별 온도 요건을 정의하고, 성능해석 결과와 비교하였으며, 이를 통해 모든 온도 요건을 만족함을 최종 확인하였다. 이러한 온도 분포는 열응력 평가를 위해 구조해석 입력자료로 활용되었다.