• 제목/요약/키워드: natural effect

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모듈형 부유구조물의 유닛 크기 및 커넥터 강도에 따른 고유모드 고찰 (Investigation of Natural Modes of Moduled Floating Structure Considering Unit Size and Connector Stiffness)

  • 김병완;홍사영;경조현
    • 한국소음진동공학회논문집
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    • 제18권3호
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    • pp.356-360
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    • 2008
  • This paper investigates the natural modes of moduled floating structure with module unit connector. As an example structure, a floating parking place($120m\;{\times}\;60m$) is considered. In the evaluation of natural modes, numerical equations are formulated by FEM(finite element method) and the natural modes are solved by the subspace iteration method. By comparing results for various sizes of module unit, the effect of unit size is investigated. By comparing results for various stiffness of module unit connector, the effect of stiffness of unit connector is also examined.

직사각형 구멍을 갖는 직사각형 평판의 접수진동 (Hydroelastic Vibration of a Rectangular Plate with a Rectangular Hole)

  • 곽문규;한상보
    • 한국소음진동공학회논문집
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    • 제22권1호
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    • pp.29-37
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    • 2012
  • This paper is concerned with the natural vibration characteristics of a rectangular plate with a rectangular hole in contact with the water. The addressed problem was solved by using the Rayleigh-Ritz method combined with the Green function method. This study presents the numerical approach, numerical results and experimental results. In addition, the validity of the approximate formula which mainly depends on the so-called non-dimensionalized added virtual mass incremental factor and the natural mode shape change due to the presence of the water were investigated. Experiments were also carried out to validate theoretical results. The theoretical results are in good agreement with the experimental results. It was found that the effect of a square hole on the natural frequencies of the square plate in contact with water is different from the effect of a square hole on the natural frequencies of the square plate in air and the approximate formula can predict lower natural frequencies in water with a good accuracy.

생봉독을 이용한 돼지 관절염의 치료효과 (The Therapeutic Effect of Pigs with Arthritis by Natural Honeybee (Apis mellifera) Venom)

  • 조성구;최석화;최향순;강성수;권영방
    • 한국임상수의학회지
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    • 제16권1호
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    • pp.145-149
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    • 1999
  • This study was designed to examine therapeutic effect of natural honeybee (Apis mellifera) venom in pigs with arthritis. Pigs were assigned to treated and nontreated control groups. In treated group, 51 pigs were given natural honeybee venom once a day for 5 consecutive days. Acupoints of Sam-li, Jok-su and Pal-ja were stung by the natural honey bees. In control group, 46 pigs were intramuscularly injected with a standard dosage of penicillin G (400,000 IU/kg of body weight) once a day for 5 consecutive days. On day 5 following bee venom therapy, 73.9% of control pigs and 86.2% of pigs in treated group recovered from arthritis. Bee acupuncture therapy did not show any side effects such as allergy, intoxication, hemorrhage, or infection. It might be concluded that honeybee venom therapy was effective in controlling of pig with arthritis.

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Determinants of Bilateral Foreign Direct Investment Intra-ASEAN : Panel Gravity Model

  • Zebua, Hasrat Ifolala;Nasrudin, Nasrudin
    • Asian Journal of Business Environment
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    • 제6권1호
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    • pp.19-24
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    • 2016
  • Purpose - This paper aims to find and analyze factors that determine the flows of bilateral foreign direct investment in intra-ASEAN. It specifically focuses on the dimension of macro-economic, natural resources, human resources, and the quality of governance. Research design, data, and methodology - Data were collected from 64 bilateral relations between ASEAN nations from 2002 to 2013. Panel gravity model was utilized to find factors that determine the flows of bilateral foreign direct investment. Results - Significant factors were identified that determine the flows of bilateral foreign direct investment: GDP home country, GDP host country, real interest rate, distance, and total natural resources rent. Unexpectedly, natural resources have a negative effect. Conclusions - In a situation of increasing the flow of FDI among the countries of ASEAN, the government should control the interest rates and maintain good relations with nearby countries. The negative effect of total natural resource rents implies that ASEAN countries should not depend on their natural resources to attract foreign investments.

Effect of agitation speed on production of exopolymer by Pseudomonas elodea NK-2000

  • 이남규;김현숙;손창우;이유정;조영수;이진우
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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    • pp.334-337
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    • 2000
  • Extracellular polysaccharide was produced by Pseudomonas elodea NK-2000 under nitrogen limitation and aerobic condition, The effect of agiatation speed on cell growth and production of exopolymer was investigated. The agitation speed of 7.5 L fermentor ranged from 200 to 500 rpm. Production of exopolymer increased with higher agitation speed. Maximal cell growth and production of exopolymer from 2% glucose were 3.35 g/l and 3.80 g/l, respectively when agitation speed was 400 rpm.

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전단 및 단면 회전관성효과를 고려한 회전 외팔보의 면외 굽힘진동해석 (Flapwise bending vibration analysis of rotating cantilever beams considering shear and rotary inertial effects)

  • 신상하;유홍희
    • 대한기계학회논문집A
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    • 제21권10호
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    • pp.1580-1588
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    • 1997
  • A modeling method for the flapwise bending vibration of a rotating cantilever beam which has small slenderness ratio is presented in this paper. It is shown that as the slenderness ratio decreases the shear and rotary inertia effects increase. Such effects become critical for the accurate estimation of the natural frequencies and modeshapes, especially higher frequencies and modes, as the angular speed increases. It is also shown that the flapwise bending natural frequencies are higher than the chordwise bending natural frequencies. The discrepancy between first natural frequencies are especially significant when the hub radius ratio is small.

접착제 접합된 자연섬유강화 복합재료의 파괴 강도특성에 미치는 섬유방향의 영향 (Effect of Fiber Orientation on Failure Strength Properties of Natural Fiber Reinforced Composites including Adhesive Bonded Joints)

  • 임재규;윤호철;이상용
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2005년도 추계학술발표대회 개요집
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    • pp.94-96
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    • 2005
  • This paper is concerned with a fracture strength study of composite adhesive lap joints. The tensile and peel tests were carried out on specimen manufactured hybrid stacked composites such as the polyester and bamboo natural fiber layer. The main objective of the work was to test the failure strength of adhesive bonded joints using hybrid stacked composites with a polyester and bamboo natural fiber layer adjacent to the fiber orientation. From results, the load directional orientation, small amount and low thickness of bamboo natural fiber layer have a good effect on the tensile and peel strength of natural fiber reinforced composites. and these characters are have a great influence on fracture strength and failure shape of adhesive bonded joints using hybrid stacked composites in the difference of fiber orientation.

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황색계 천연색소 추출물의 항균 특성 (Antibacterial Characteristics of the Extracts of Yellow Natural Dyes)

  • 한신영;최석철
    • 한국염색가공학회지
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    • 제12권5호
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    • pp.315-322
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    • 2000
  • The purpose of this study was to investigate the antibacterial effects of natural colors extracted from yellow natural dyes(Tumeric, Amur Cork Tree and Onion Shell). The water and the methanol extracts of Tumeric and Amur Cork Tree significally decreased the growth of E. coli in vitro and the methanol extract of Tumeric exhibited the strongest inhibitory effect among the samples. Silk and nylon fabrics dyed with water and methanol extracts of the yellow natural dyes showed antimicrobial activities against E. coli and Staph aureus in the Bioassay Test. Nylon fabric dyed with methanol extracts of them showed strong antibacterial effect on E. coli compared with that of water extracts. However, slik fabrics dyed with the extracts could not reduce the growth of E. coli. Silk or nylon fabrics dyed with methanol or water extracts of yellow natural dyes showed antimicrobial activities against Staph aureus. The antimicrobial activity of the fabrics dyed with methanol extracts from Tumeric, Amur Cork Tree and Onion Shell was stronger than that of water extracts, especially, the fabrics dyed with Tumeric extract showed the highest antibacterial property among the dyed fabrics.

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Cytotoxic Effects of Methanol Extracts from Medicinal Plants on Cancer Cell Lines

  • Lee, Jeong-Ho;Chun, Hyun-Ja;Lee, Ki-Nam;Lim, Jin-A;Ryu, Hyeong-Won;Baek, Seung-Hwa
    • 대한약학회:학술대회논문집
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    • 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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    • pp.210.3-210.3
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    • 2003
  • This study was performed to determine the cytotoxic effect of methanol extract from medicinal plants. The cell viability was determined by the MTT method. Their cytotoxic activities against three cancer cell lines such as A549, MDA-MB-231 and SNU-C4 cell line were tested. Among them, The methanol extract of Saururus Chinensis Bail showed the strongest cytotoxic effect against SNU-C4 cells. These results suggest that the methanol extract of Saururus Chinensis Bail possessed a potential antitumorous agent

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Electro-optic Properties of a Guest-Host System Containing a Phenothiazine-based Chromophore: Effect of the Chromophore Density on the Macroscopic Optical Nonlinearity

  • Lee, Sang-Kyu;Cho, Min-Ju;Yoon, Hyuk;Lee, Seung-Hwan;Kim, Jae-Hong;Qing Zhang;Choi, Dong-Hoon
    • Macromolecular Research
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    • 제12권5호
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    • pp.484-489
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    • 2004
  • We have prepared a phenothiazine-based nonlinear optical (NLO) chromophore that displays a fairly high microscopic nonlinearity through intramolecular charge transfer. The phenothiazine unit plays important roles of contributing its high electron donating ability and connecting the resonance pathway through a conjugative effect in the cyclized ring adjacent to the aromatic ring. Theoretical calculations and an absorption spectroscopic study provided useful information concerning the microscopic nonlinearity of the chromophores. We investigated the electro-optic (EO) properties of the guest-host systems in amorphous polycarbonate containing the synthesized chromophores at different concentrations under different poling temperatures. A real-time pole and probe method provided a much greater amount of information regarding how the EO properties can arise and how they can be optimized.