• 제목/요약/키워드: Protective structure

검색결과 324건 처리시간 0.024초

왕릉의 식생경관구조 및 관리대책에 관한 연구(II)-헌인릉 식물군집의 천이- (Studios on the Vegetational Landscape Structure and Administration Planning of the Royal Tomb (II)-Successional Trends of the Plant Community of Heonin Royal Tomb-)

  • 이경재;오구균;우종수;송근준
    • 한국조경학회지
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    • 제17권3호
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    • pp.35-47
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    • 1990
  • This study was executed to analyze the vegetational landscape structure and administration planning of Heonin Royal Tomb forest by three kinds of ordination techniques (PCA, RA and DCA) and comparison of the couple photographs between 1920s and 1980s. Seventeen sites in the recreation area and fifteen sites in the protective area were sampled with clumped sampling method in June 1988 and five quadrats were examined in each site. Environmental impact grade 3, 4 and 5 area covered 56.4% of the surveyed area and these area should be restored by the input of human energy. Pinus densifora community of actual vegetation covered 8.4%, Alnus japonica 24.2% and Quercus community 40.9% of the total area. And the afforested vegetation of Pinus koraiensis and Pinus rigida covered 23.1 % The recreation area was divided by P. densiflora, P. densiflora-Quercus aliena, A. japonica-Q.aliena, A. japonica and the protective area by Q. acutissima, Q. aliena, A. japonica-Q. aliena.. DCA ordination showed that successional trends of tree species seem to be from P. densiflora, Sorbus alnifolia, Styrax obassia to Q. variabilis Q. serrata in P. densiflora community and from A. japonica through A. ginnala to Q. aliena in A. japonica community of the upper layer. By the comparison of the couple photographs between 1920s and 1980s, we can recognize the change of historical landscape composed of P. densiflora community and those community is succeeded to Q. aliena.

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Experimental and numerical investigation of RC sandwich panels with helical springs under free air blast loads

  • Rashad, Mohamed;Wahab, Mostafa M.A.;Yang, T.Y.
    • Steel and Composite Structures
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    • 제30권3호
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    • pp.217-230
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    • 2019
  • One of the most important design criteria in underground structure is to design lightweight protective layers to resist significant blast loads. Sandwich blast resistant panels are commonly used to protect underground structures. The front face of the sandwich panel is designed to resist the blast load and the core is designed to mitigate the blast energy from reaching the back panel. The design is to allow the sandwich panel to be repaired efficiently. Hence, the underground structure can be used under repeated blast loads. In this study, a novel sandwich panel, named RC panel - Helical springs- RC panel (RHR) sandwich panel, which consists of normal strength reinforced concrete (RC) panels at the front and the back and steel compression helical springs in the middle, is proposed. In this study, a detailed 3D nonlinear numerical analysis is proposed using the nonlinear finite element software, AUTODYN. The accuracy of the blast load and RHR Sandwich panel modelling are validated using available experimental results. The results show that the proposed finite element model can be used efficiently and effectively to simulate the nonlinear dynamic behaviour of the newly proposed RHR sandwich panels under different ranges of free air blast loads. Detailed parameter study is then conducted using the validated finite element model. The results show that the newly proposed RHR sandwich panel can be used as a reliable and effective lightweight protective layer for underground structures.

Antioxidant activity and cell protective effect of loliolide isolated from Sargassum ringgoldianum subsp. coreanum

  • Yang, Xiudong;Kang, Min-Cheol;Lee, Ki-Wan;Kang, Sung-Myung;Lee, Won-Woo;Jeon, You-Jin
    • ALGAE
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    • 제26권2호
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    • pp.201-208
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    • 2011
  • A monoterpene lactone, loliolide was successively isolated from brown seaweed, Sargassum ringgoldianum subsp. coreanum using column chromatography and high-performance liquid chromatography. The structure of the isolated compound was determined by comparison of EIMS and NMR spectral data with the previously published data. The antioxidant activities of loliolide were also evaluated by DPPH and $H_2O_2$ radical and intracellular reactive oxygen species scavenging assays, and it showed moderate activities in all antioxidant assays. Furthermore, loliolide was found to exert positive dose-dependent effects in the protective effects against $H_2O_2$-induced cell damage which were determined via MTT, Hoechst staining assays and cell cycle analysis. This is the first study on chemical constituent of this seaweed according to our best knowledge. These results clearly indicated that loliolide isolated from Sargassum ringgoldianum subsp. coreanum can protect the cells against $H_2O_2$-induced cell damage or apoptosis.

인체보호용 헬멧의 구조 및 기술 (Structure and Technology of Personal Protection Helmets)

  • 황재형;정원영
    • 한국의류학회지
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    • 제41권4호
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    • pp.771-781
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    • 2017
  • The helmet is an imperative personal protective equipment. This protective device must be able to guard the human head against potential risks. Helmets are classified according into the purpose of use; therefore, the required performance and specifications depend on the type of products. Military helmets are intended to protect the wearer's head from bullets and shrapnel. Generally, lightweight super fibers and fiber reinforced composite materials are used as helmet shell materials, and NIJ STD of U.S. Department of Justice is most widely used as international standard related to bulletproof helmets. Safety helmets are widely used for industrial application and sports leisure. In general, the performance of shock absorption must be ensured, and various lining systems are applied in material, design, and combination methods. Evaluation standards have also been classified and strictly controlled for each purpose; therefore, it is difficult to certify with the existing standards such as the recently developed convergence helmets. However, it is possible to launch the product through a separate national integrated certification procedure.

CrAlN과 CrZrN의 산화 (Oxidation of CrAlN and CrZrN Films)

  • 김민정;김슬기;이상율;이동복
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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    • pp.33-35
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    • 2011
  • Films of CrAlN and CrZrN were deposited on a steel substrate by closed field unbalanced magnetron sputtering, and their oxidation behaviors were investigated. CrAlN films consisted of dense, polycrystalline CrN and AlN fine columns. The formed oxides consisted primarily of crystalline $Cr_2O_3$ incorporated with $Al_2O_3$. The oxide layers were thin and compact so as to make CrAlN films more protective than CrN films. In case of CrZrN films, Zr atoms were dissolved in the CrN phase. Zr atoms advantageously refined the columnar structure, reduced the surface roughness, and increased the micro-hardness. However, the addition of Zr did not increased oxidation resistance, mainly because Zr was not a protective element. All the deposited films displayed relatively good oxidation resistance, owing to the formation of the highly protective $Cr_2O_3$ on their surface. The $Cr_{40}Zr_9N$ and $Cr_{31}Zr_{16}N$ films oxidized to $Cr_2O_3$ as the major phase and ${\alpha}-ZrO_2$ as the minor one, whereas the CrN film oxidized to $Cr_2O_3$.

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유해환경으로부터 개인의 안전보호를 위한 패션 마스크 디자인 경향 (A study on fashion mask design trends for individual safety protection from harmful environments)

  • 이달아;김찬호
    • 한국의상디자인학회지
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    • 제24권4호
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    • pp.101-116
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    • 2022
  • The purpose of this study is to understand the trends of fashion mask designs as a fashion item with characteristics to protect individual health and safety from harmful environments. To this end, the concept, the trend analysis of the domestic and foreign mask markets, the type, characteristics of functional masks, and the design trend of fashion masks were analyzed. Research methods included case studies and literaturte on mask design, fashion magazines, fashion brand websites, fashion collections, and promotional material. First, masks for personal safety were classified as protective function masks from the natural environment, functional masks by industrial groups, masks for protective functions from biohazards, and masks for protective functions from various external activities. Through this analysis, the design trends of fashion masks were analyzed. The functional orientation of structure and functionality, the environmental orientation of sustainable eco-friendly methods, the fashion orientation of individual fashion styling, and the social functional orientation tend to transmit social messages. In the harmful environment of everyday life, items such as fashion masks with functionality and fashion characteristics should be continuously studied to integrate functional and design characteristics that can contribute to the future fashion industry and the fashion market as a sense of unity and responsibility.

Characterization, Antioxidant Capacity and Protective Effect of Peptides from Cordyceps militaris Cultivated with Tussah Pupa on Oxidative Injured HepG2 Cells

  • Bingxin Li;Jinying Zhang;Yefei Liu;Ze Wang;Fangxu Xu
    • Journal of Microbiology and Biotechnology
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    • 제34권5호
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    • pp.1082-1091
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    • 2024
  • The antioxidant capacity and protective effect of peptides from protein hydrolysate of Cordyceps militaris cultivated with tussah pupa (ECPs) on H2O2-injured HepG2 cells were studied. Results indicated ECP1 (<3 kDa) presented the strongest antioxidant activity compared with other molecular weight peptides. Pretreated with ECPs observably enhanced survival rates and reduced apoptosis rates of HepG2 cells. ECPs treatment decreased the ROS level, MDA content and increased CAT and GSH-Px activities of HepG2 cells. Besides, the morphologies of natural peptides from C. militaris cultivated with tussah pupa (NCP1) and ECP1 were observed by scanning electron microscopy (SEM). Characterization results suggested the structure of NCP1 was changed by enzymatic hydrolysis treatment. Most of hydrophobic and acidic amino acids contents (ACC) in ECP1 were also observably improved by enzymatic hydrolysis. In conclusion, low molecular weight peptides had potential value in the development of cosmetics and health food.

파일지지 구조물의 선박 충돌거동에 대한 해석 (Analysis of Ship Collision Behavior of Pile Supported Structure)

  • 배용귀;이성로
    • 대한토목학회논문집
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    • 제28권3A호
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    • pp.323-330
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    • 2008
  • 선박과 방호구조물 충돌시 구조물의 동적 특성들을 분석하기 위하여 항로상에 위치한 교량의 방호구조물인 강관파일그룹에 대한 선박충돌해석을 수행하였다. 해석은 선박과 파일의 유한요소 모델링, 비선형성 재료의 모델링, 강성충돌해석, 변위기반해석 그리고 충돌시나리오에 대한 연성충돌해석 등을 포함하고 있다. 강체벽에 대한 강성충돌해석을 통하여, 선수부의 충돌유형에 따른 충돌하중을 산정하였다. 변위기반 해석에서 방호시스템이 최대 수평 이격거리 내에서 흡수할 수 있는 대략적인 에너지의 범위를 산정할 수 있었다. 충돌시나리오별 연성충돌해석에서는 충돌시 거동을 방호시스템 설계를 고려하면서 검토하였다. 파일지지구조물의 에너지소산 메카니즘 분석을 통해 방호구조물의 최적 설계를 도출할 수 있다.

광섬유 센서를 이용한 복합 섬유 재료로 보강된 철근 콘크리트 보의 모니터링 (Monitoring of Retrofitted Reinforced Concrete Beams with Hybrid Fiber Reinforced Polymer)

  • 이옥기;신영수;김기수;김종우
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.509-514
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    • 2001
  • The Fibre-optic Bragg grating (FBG) sensor is broadly accepted as a structural health monitoring device for Fibre reinforced plastic (FRP) materials by either embedding into or bonding onto the structures. The accuracy of the strain measured by using the FBG sensor is highly dependent on the bonding characteristics among the bare optical fibre, protective coating, adhesive layer and host material. In general, the signal extracted from the embedded FBG sensor should reflect the straining condition of the host structure. This paper presents a theoretical model to evaluate the differential strains between the bare fibre and host material with different adhesive thickness and modulus of the protective coating of the embedded FBG sensor.

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A New Technology of Hardening Porous Materials of Titan Powders

  • Belyavin, K.E.;Minko, D.V.;Reshetnikov, N.V.
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.1012-1013
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    • 2006
  • A technology of hardening porous materials of titan powders has been elaborated. The technology is based on passing alternating current with duration of ${\sim}10^{-1}{\ldots}10^1$ s through porous ($35{\ldots}40%$) blanks made by method of Sintering by Electric Discharge (SED) by passing a pulse of current with duration of ${\sim}10^{-5}{\ldots}10^{-3}$ s. The influence of technological regimes of porous blanks treatment on their structure and properties is investigated. Geometry and dimension of contact necks between powder particles of obtained samples are evaluated. Variations of porosity and strengths as well as microstructure of porous samples materials before and after treatment are investigated. Optimum range of treatment technological regimes is determined within which porosity of $30{\ldots}35%$ with maximum strength values.

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