• 한국세라믹학회지
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• 제55권2호
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• pp.166-173
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• 2018

In order to investigate the effect of Mn on the dielectric and piezoelectric properties of PMN-PT [$Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$], four different types of 71PMN-29PT samples were prepared using the solid-state single crystal growth (SSCG) method: (1) Undoped single crystals, (2) undoped polycrystalline ceramics, (3) Mn-doped single crystals, and (4) Mn-doped polycrystalline ceramics. In the case of single crystals, the addition of 0.5 mol% Mn to PMN-PT decreased the dielectric constant ($K_3{^T}$), piezoelectric charge constant ($d_{33}$), and dielectric loss (tan ${\delta}$) by about 50%, but increased the coercive electric field ($E_C$) by 50% and the electromechanical quality factor ($Q_m$) by 500%, respectively. The addition of Mn to PMN-PT induced an internal bias electric field ($E_I$) and thus specimens changed from piezoelectrically soft-type to piezoelectrically hard-type. This Mn effect was more significant in single crystals than in ceramics. These results demonstrate that Mn-doped 71PMN-29PT single crystals, because they are piezoelectrically hard and simultaneously have high piezoelectric and electromechanical properties, have great potential for application in fields of SONAR transducers, high intensity focused ultrasound (HIFU), and ultrasonic motors.

• Toxicological Research
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• 제33권1호
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• pp.49-54
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• 2017

Vitamin D3 is a fat-soluble secosteroid responsible for enhancing intestinal absorption of calcium, iron, and other materials. Vitamin D3 deficiency, therefore, can cause health problems such as metabolic diseases, and bone disorder. Female sex hormones including estrogen and progesterone are biosynthesized mainly in the granulosa cells of ovary. In this study, we isolated granulosa cells from porcine ovary and cultured for the experiments. In order to examine the effect of vitamin D3 on the ovarian granulosa cells, the mRNA and protein levels of genes were analyzed by real-time PCR and Western blot assay. The production of estrogen from the granulosa cells was also measured by the ELISA assay. Genes associated with follicle growth were not significantly altered by vitamin D3. However, it increases expression of genes involved in the estrogen-biosynthesis. Further, estrogen concentrations in porcine granulosa cell-cultured media increased in response to vitamin D3. These results showed that vitamin D3 is a powerful regulator of sex steroid hormone production in porcine granulosa cells, suggesting that vitamin D deficiency may result in inappropriate sexual development of industrial animals and eventually economic loss.

• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.780-784
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• 2011

As the popularization and development of 3D display makes common users easy to experience a solid 3D virtual reality, the demand for virtual reality contents are increasing. In this paper, we propose 3D panorama system using vanishing point locationbased depth map generation method. 3D panorama using depthmap stitching gives an effect that makes users feel staying at real place and looking around nearby circumstances. Also, 3D panorama gives free sight point for both nearby object and remote one and provides solid 3D video.

• 약학회지
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• 제48권4호
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• pp.254-260
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• 2004

Structure-activity relationship studies of allylamine type of antimycotics were carried out to evaluate the effect of naphthyl and methyl portion of naftifine. Compounds with 2,4-difluorophenyl( 2a-5a), 2,5-difluorophenyl(2b-5b), 4-ethylphenyl(2c-5c), 2-hydroxyphenyl(2d-5d) and 2-methylnaphthyl(2e-5e) instead of naphthyl group with hydrogen(3a-3e), methyl(4a-4e), and ethyl(5a-5e) in the place of methyl in naftifine were synthesized and tested their in vitro anti-fungal activity against five different fungi. Eight compounds( 3a, 4a, 5a, 3d, 4d, 4d, 5d, 3e, and 4e) showed significant anti-fungal activity against T. mentagroPhytes. (E)-N-(3-Phenyl-2-propenyl)-2- hydroxy-benzenemethaneamine( 3d) displayed moderate antifungal activity against all five different fungi.

• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.269-275
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• 2022

자작나무(Betula platyphylla) 수피 추출물에는 생리활성을 보일 수 있는 다수의 terpenoids 물질이 포함되어 있고 염증반응을 완화시키는 치료제로 사용되어 왔다. 본 연구는 탈모예방 효과를 보일 수 있는 천연 물질을 확보하기 위해 자작나무를 여러 용매에서 추출 및 분리 정제하여 몇몇 분획을 획득하였다. 이를 사용하여 사람 모낭 모유두세포(HDP)에 대한 세포 독성 및 성장촉진 효과 그리고 β-catenin, VEGF, IGF1, Cyclin D의 발현변화와 5-α-reductase activity에 미치는 영향을 평가하였다. Ethyl acetate를 이용하여 분리한 4개의 분획 중 H3-2 분획은 알려진 유효물질인 ETB, LPO와 동등수준의 모낭 모유두세포(HDP)에 대한 성장 촉진 효과를 보였고 성장에 관여하는 주요인자들의 발현을 높이는 효과를 보였다. 또한, 5-α-reductase activity에 ETB, LPO가 큰 영향을 보이지 못한 반면 최종분획물인 H3은 5-α-reductase activity 감소활성이 있음을 확인할 수 있었다.

• 산업경영시스템학회지
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• 제37권3호
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• pp.24-35
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• 2014

This paper examines, from the perspective of the structure-conduct-performance (S-C-P) paradigm, the structural factors that determine R&D concentration in industries. The results are as follows. First, an industry's R&D concentration is directly related to its market concentration, R&D intensity, capital intensity, and technological opportunities. In contrast, the higher an industry's performance, the more likely the diffusion of R&D investment is for firms belonging to that industry. Second, an industry's R&D concentration has a positive effect on its market concentration but a negative effect on its performance, suggesting that governments should adopt R&D policies that would induce more firms to invest in R&D instead of focusing only on a few firms to enhance industry performance.

• 경영과학
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• 제25권3호
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• pp.13-26
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• 2008

We investigate the effect of government and public sector R&D Investment at IT Industry on the amount of Production, export and nongovernment R&D Investment at IT Industry. We, firstly, examine the stationarity of each variable by the unit root t-test and perform the co-integration test for the pairs of variables. We use YECM(Vector Error Correction Model) according to the results of co-integration test for the examination of Granger-causality between variables. It is found that there exist an Granger-causality between public sector R&D Investment and nongovernment R&D investment and also between public sector R&D Investment and export. Secondly, we analyze the impulse response of government and public sector R&D Investment at IT Industry on the amount of production, export and nongovernment R&D investment at IT Industry based on VECM model. It is found that the response of the amount of production is highest at 3th period and is lowest at 8th period and that of export shows similar pattern.

• Journal of Animal Science and Technology
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• 제64권2호
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• pp.302-311
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• 2022

This study investigated the effect of a synergistic blend of free and buffered organic acid (FMP) on the performance of piglets born to sows supplemented with a blend of short- and medium-chain organic acids (SGG) during the late gestation and lactation period. A total of 150 multiparous sows (n = 50/treatment, Landrace × Yorkshire) were blocked (2.4 parity) and assigned to 1 of 3 dietary treatments: CON - corn-soybean meal-based basal diet, SGG-Low - CON+ 1.5 kg/ton SGG, and SGG-High - CON + 3kg/ton SGG. During weaning, 600 piglets (6.72 ± 0.5kg) which weaned from sows supplemented with 3 levels of SGG were allocated to 2 weaner diets (Control and FMP - 3kg/ton) following 3 × 2 factorial arrangement. Supplemental effects on performance were measured at d0-d21 and d 21-42, and the entire period. Pigs fed with FMP and born to sows supplemented with SGG-High gained more weight and ate more (p < 0.05) compared with those in the CON group in both phases, and with SGG-Low in the second phase. Over the entire post-weaning period, piglets born to sows supplemented with SGG-Low and SGG-High had a higher average daily gain (ADG) and body weight (BW) (p < 0.05). Regardless of sow treatment, pigs fed with an FMP diet had higher ADG (p < 0.001), BW (p = 0.045), and a lower feed conversion ratio (p = 0.033). Also, feeding FMP diets reduced the fecal Escherichia coli and Clostridium perfringens counts at d42. The current study indicates that sows fed SGG supplement had a positive carry-over effect on the post-weaning growth rate, and FMP supplement enhances the growth performance and reduced the number of C. perfringens and E. coli. Thus, the application of 3 kg/ton of SGG in sows' diet and subsequent feeding of piglets with FMP would be an effective strategy to improve growth rate and reduce pathogenic bacteria in post-weaned piglets.

• 산업진흥연구
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• 제8권2호
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• pp.1-9
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• 2023

본 연구는 4차 산업혁명 관련 연구에 존재하는 간극을 메우고자, 4차 산업혁명 핵심기술과 기업의 경제적 성과 간 상관관계를 탐색적으로 살펴본다. 실증분석 결과, 각 4차 산업혁명 핵심기술의 도입 여부는 기업의 매출액과 통계적으로 유의미한 양(+)의 상관관계가 존재했다. 상관관계의 크기는 3D 프린팅(139%), 빅데이터(129%), 클라우드 컴퓨팅(127%), 인공지능(78%), 사물인터넷(70%) 순으로 나타났다. 이들 4차 산업혁명 핵심기술 도입이 기업의 매출액에 미치는 상호작용효과를 검정한 결과, 사물인터넷과 3D 프린팅, 클라우드 컴퓨팅과 빅데이터, 클라우드 컴퓨팅과 3D 프린팅 간에는 통계적으로 유의미한 음(-)의 상호작용효과가 나타났다. 본 연구는 4차 산업혁명 핵심기술과 기업의 경제적 성과 간 상관관계를 살피는 초기적 시도로 향후 이와 관련한 실증연구의 기초로 활용할 수 있다.

• 한국항해항만학회지
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• 제29권3호
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• pp.257-262
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• 2005

본 연구는 최근의 연안역 개발 사업 이전에 선행되어야 하는 물리학적 변화요인들( 파랑변형과 주변해역의 해양 환경적 변화 요인 등)에 대한 연구에 그 목적이 있다. 이러한 관점에서 울산 신항과 같은 연안역에서의 DELFT-3D: WAVE(SWAN)을 이용하여 대상 해역의 파랑특성을 파악했다, 파랑특성 파악을 위해서 다방향 불규칙파의 굴절 및 천수변형을 동시에 풀 수 있는 에너지 평형 방정식을 사용한 수치모델인 SWAN 모델에 대해 연구하였다. 이러한 과정을 통해서 울산 신항 주변 해역의 불규칙 파랑특성을 파악했다. 파랑특성 파악의 가상 좋은 방법은 현장 파고계를 설치하여 장기간에 걸쳐 파랑을 직접 관찰하는 것이다. 그러나 광범위한 지역에 대한 파랑특성 파악에는 어려움이 있어서 이에 대한 대안으로 수치모텔인 DELFT-3D; WAVE를 이용해서 불규칙 파랑특성을 파악했다.