• Journal of the Korean Wood Science and Technology
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• 제45권3호
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• pp.317-326
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• 2017

산사나무 목질부 및 수피부를 70% acetone 수용액으로 추출하고 목질부는 n-hexane, chloroform ($CHCl_3$), n-butanol (n-BuOH) 및 수용성 추출물로 분획하였으며, 수피부는 n-hexane, chloroform, ethylacetate (EtOAc) 및 수용성으로 분획한 후, 각 추출 분획에 대하여 항산화 및 항염활성 평가를 실시하였다. 항산화 활성은 목질부에서는 n-BuOH용성이, 수피부에서는 EtOAc용성이 가장 좋은 활성을 보였으며, 특히 수피부 EtOAc용성은 대조군으로 사용된 buthylated hydroxytoluene (BHT) 및 ${\alpha}$-tocopherol에 비하여 매우 우수한 항산화 활성을 나타냈다. 항염활성은 목질부 수용성을 제외한 모든 분획물들이 nitric oxide (NO) 생성을 억제하는 효과를 보이고 있었으며, 수피부 조추출물과 수용성 분획에서 가장 우수한 NO 생성 억제효과를 나타내었다. 이와 같은 결과를 토대로 볼 때, 산사나무 추출물은 항산화제 및 항염제로 이용될 수 있는 천연 바이오매스 자원으로써의 가능성을 나타내었다.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 추계학술대회 논문집
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• pp.400-401
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• 2003

Atmospheric fine aerosol particles play an important role in controlling a number of atmospheric processes, such as the deposition of different compounds, the optical properties etc. (Molnar et al., 1999). In this report, water-soluble species of PM$_{2.5}$ obtained from simultaneous measurements at four Asia sites (Beijng (39.56$^{\circ}$N, 116.17$^{\circ}$E), China; Gwangju (35.10$^{\circ}$N, 126.53$^{\circ}$E), South Korea; Kyoto (35.01$^{\circ}$N, 135.44$^{\circ}$E), Japan; and Ulan-Bator (47.55$^{\circ}$N, 106.52$^{\circ}$E), Mongolia) during the periods of 14-22 August, 30 October-06 November 2000, 14-21 January 2001, 23 July-02 August and 05-16 November 2002, within the framework of an APN (The Asia-Pacific Network for Global Change Research) project are reported. Ion components in 23 July-02 August 2002 were not obtained because of the technical problem of equipments.s.

• Journal of Electrochemical Science and Technology
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• 제9권4호
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• pp.320-329
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• 2018

Natural graphite is obtained from an abandoned open-cast mine and purified by a simple, eco-friendly and affordable beneficiation process including ball milling and flotation process. Both raw graphite (55 wt %) and its concentrate (85 wt %) were electrochemically tested in order to evaluate these materials as anode materials for Li-ion and Na-ion batteries. It was found that both raw and purified graphites exhibit good electrochemical activities with respect to lithium and sodium ions through completely different reaction mechanisms. The encouraging results demonstrated in this work suggest that both raw and graphite concentrates after flotation could be used respectively for stationary and embedded applications. This strategy would help in developing local electrical storage systems with a significantly low environmental footprint.

• 한국식품과학회지
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• 제37권4호
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• pp.656-659
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• 2005

신선초의 기능성 해명과 유용 기능성성분 탐색연구의 일환으로 신선초 지상부로부터 항산화활성물질을 분리하여 구조 해석하였다. 신선초 지상부의 열수추출물을 용매분획하여 ethyl acetate 가용 중성획분을 얻었다. 이를 Sephadex LH-20 column chromatography와 HPLC로 정제하여 항산화활성물질 2종을 단리하고, 그들 각각의 화합물을 대상으로 FAB-MS와 NMR 분석을 실시한 결과, pseudoisopsoralen과 8-methoxypsoralen(xanthotoxin)으로 동정하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권4호
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• pp.569-579
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• 2013

A steel-type breakwater that uses a submerged dual horizontal porous plate was originally proposed by Kweon et al. (2005), and its hydrodynamic characteristics and design methodology were investigated in a series of subsequent researches. In particular, Kweon et al. (2011) proposed a method of estimating the vertical uplift force that acts on the horizontal plate, applicable to the design of the pile uplift drag force. However, the difference between the method proposed by Kweon et al. (2011), and the wave force measured at a different time without a phase difference, have not yet been clearly analyzed. In this study, such difference according to the method of estimating the wave force was analyzed, by measuring the wave pressure acting on a breakwater model. The hydraulic model test was conducted in a two-dimensional wave flume of 60.0 m length, 1.5 m height and 1.0 m width. The steepness range of the selected waves is 0.01~0.03, with regular and random signals. 20 pressure gauges were used for the measurement. The analysis results showed that the wave force estimate in the method of Kweon et al. (2011) was smaller than the wave force calculated from the maximum pressure at individual points, under a random wave action. Meanwhile, the method of Goda (1974) that was applied to the horizontal plate produced a smaller wave force, than the method of Kweon et al. (2011). The method of Kweon (2011) was already verified in the real sea test of Kweon et al. (2012), where the safety factor of the pile uplift force was found to be greater than 2.0. Based on these results, it was concluded that the method of estimating the wave force by Kweon et al. (2011) can be satisfactorily used for estimating the uplift force of a pile.

• Steel and Composite Structures
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• 제34권5호
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• pp.643-655
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• 2020

In the present work, the buckling behavior of a single-layered graphene sheet (SLGS) embedded in visco-Pasternak's medium is studied using nonlocal four-unknown integral model. This model has a displacement field with integral terms which includes the effect of transverse shear deformation without using shear correction factors. The visco-Pasternak's medium is introduced by considering the damping effect to the classical foundation model which modeled by the linear Winkler's coefficient and Pasternak's (shear) foundation coefficient. The SLGS under consideration is subjected to compressive in- plane edge loads per unit length. The influences of many parameters such as nonlocal parameter, geometric ratio, the visco-Pasternak's coefficients, damping parameter, and mode numbers on the buckling response of the SLGSs are studied and discussed.

• Geomechanics and Engineering
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• 제34권3호
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• pp.233-250
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• 2023

This paper investigates the flexural analysis of isotropic, transversely isotropic, and laminated composite plates using a new higher-order normal and shear deformation theory. In the present theory, only five unknown functions are involved compared to six or more unknowns used in the other similar theories. The developed theory does not need a shear correction factor. It can satisfy the zero traction boundary conditions on the top and the bottom surfaces of the plate as well as account for sufficient distribution of the transverse shear strains. The thickness stretching effect is considered in the computation. A simply supported was considered on all edges of the plate. The plate is subjected to uniform and sinusoidal distributed load in the static analysis. Laminated composite, isotropic, and transversely isotropic plates are considered. The governing equations are obtained utilizing the virtual work principle. The differential equations are solved via Navier's procedure. The results obtained from the developed theory are compared with other higher-order theories considered in the previous studies and 3D elasticity solutions. The results showed that the proposed theory accurately and effectively predicts the bidirectional bending responses of laminated composite plates. Several parametric studies are presented to illustrate the various parameters influencing the static response of the laminated composite plates.

• Computers and Concrete
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• 제26권5호
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• pp.439-450
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• 2020

In this research, bending and buckling analyses of porous functionally graded (FG) plate under mechanical load are presented. The properties of the FG plate vary gradually across the thickness according to power-law and exponential functions. The material imperfection is considered to vary depending to a logarithmic function. The plate is modeled by a refined trigonometric shear deformation theory where the use of the shear correction factor is unnecessary. The governing equations of the FG plate are derived via virtual work principle and resolved via Navier solutions. The accuracy of the present model is checked by comparing the obtained results with those found in the literature. The various effects influencing the stresses, displacements and critical buckling loads of the plate are also examined and discussed in detail.

• Journal of Plant Biotechnology
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• 제48권2호
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• pp.100-105
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• 2021

Genetic engineering is a potential approach to improve secondary metabolism in plants. In order to elucidate the effect of production of anthocyanin pigment 1 (PAP1) overexpression on the bioactivity of ginseng, we analyzed its antioxidant, antimicrobial, and anti-elastase activities in this study. Our results showed that PAP1 overexpression increased the production of polyphenolic compounds including anthocyanins. The antioxidant, antimicrobial, and anti-elastase activities were stronger in anthocyanin-overproducing ginseng hairy roots (AOX) than in wild ginseng hairy roots. Using a different solvent system (0, 30, 70, and 100% (v/v) EtOH), we revealed that variations in the contents of the polyphenolic compounds were highly correlated with changes in the antioxidant and antimicrobial activities of AOX. The antioxidant, antimicrobial, and anti-elastase effects of AOX highlight genetic engineering as a powerful approach to enhance the therapeutic properties of plants. Our results show that AOX could potentially have various functional applications in the cosmetic and pharmaceutical industries.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2003년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.252-253
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• 2003

바지락포자충 Perkinsus는 미국과 유럽 등지에서 굴과 바지락에 기생하며 고수온기숙주의 대량 폐사를 유발하는 원생동물로 이에 대한 연구가 활발하게 진행 중인 패류질병이다. Choi 와 Park (2001), Choi et at.(2002)은 우리나라 전 연안과 일본 Isahaya Bay에 서식하는 바지락에서 Perkinsus를 검출하고 이들의 감염도와 조직병리학적 특성을 보고한 바 있다. (중략)