• 제목/요약/키워드: Aging Properties

검색결과 1,327건 처리시간 0.032초

황색종 잎담배의 발효숙성 촉진에 관한 종합적 연구 (A Comprehensive Study on the Forced Aging of Flue-cured Tobacco-Leaves)

  • 배효원
    • Applied Biological Chemistry
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    • 제13권1호
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    • pp.1-27
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    • 1970
  • 황색종 잎담배의 인공발효숙성은 효모처리에 의한 인공발효, 단순한 인공숙성, 2년 저장숙성 및 미처리구로 나누어 미생물학, 물리학, 화학, 생화학적으로 그 변화과정을 종합적으로 연구하여 다음과 같은 결과를 얻었다. 1. 한국산 잎담배 Y.S.A의 발호숙성을 촉진시키는 최적 조건으로서는 및 담배를 온도 $40^{\circ}C$평형함수율 18%, 관계습도 74%에 놓아두는 것이 잎담배의 모든 품질적 특성에 가장 양호한 결과를 주는 것임을 알게되었다. 2. 잎담배를 $40^{\circ}C$의 숙성온도 및 74%의 상대습도에서 효모를 첨가하여 약 20일 내외에서 숙성을 촉진시켜 숙성시키면 잎담배의 여러가지 물리적 및 화학적 특성이 1년 및 2년 저장숙성시킨 것과 비슷하게 됨을 알게 되었음으로 그 실용적 효과를 입증할 수 있었다. 3. 온도 $40^{\circ}C$와 평형함수율 18%의 숙성조건하에서 잎담배에 효모를 첨가하여 또는 단순히 조기숙성시켰을 때 잎담배는 그 숙성에 필요한 물리화학적 특성은 약 20일만에 얻을 수 있다는 것을 알게되었다. 4, 본 실험에서 잎담배의 발효숙성기간중 미생물의 동태는 효모와 세균은 15일까지 증가하였다가 감소하였고 곰팡이류는 끝까지 계속 증가하였다. 5, 효모구 및 속성구 잎담배의 이화학성은 발효숙성이 $15{\sim}20$일 진행함에 따라 pH는 저하하였고 팽승성과 연소성이 양호하여 졌고 자극순도, 명도주재파장등 색택에 관련되는 물리성이 2년저장 잎담배와 비등하여졌다. 또 총환원성물질, 전당, 전환원당, 알카로이드량은 감소하였고 유기산, ether 추출물은 증가, 전질소 및 단백질량, 조섬유, 회분등은 별 변화가 없었다. 6. 효모 및 속성구의 잎담배는 발효숙성이 15-30일 진행되는 동안 그 개개의 화학성분이 다음과 같이 변화하였다. 즉, 시일이 경과함에 따라 당 류-sucrose, rhamnose, glucose 색소류-chlorophyll, carotenes, xanthophyll, violaxanthine polyphenols-rutin, chlorogenic 및 caffeic acid 유기산-iso?tutylic, crotonic, capronic, galacturonic,tartaric, succinic, citric acid 알카로이드-nicotine,nornicotine등 화합물은 감소하였다. 한편 시일이 경과함에 따라 당 류-fructose, maltose, raffnose 아미노산-proline, cystine, 유 기 산-formic, acetic, propionic, malic, oxalic,malonic, α-ketoglutaric, fumaric, glutaric acid 등 화합물은 증가하였다. 7. 잎담배 발효숙성중 생화학적 특성의 변화는 다음과 같았다. 즉, 30일간의 발효숙성기간중 산소흡수량은 점차 감소하였으며, ${\alpha}-amylase$ ${\beta}-amylase$}활성도는 점차 약하여 졌으나 catalase, invertase는 그 활성도가 일단 숙성중기에 높아졌다가 낮아졌다.

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폐타이어 재활용에 있어서 Binder양이 미치는 영향 (Effect of the Binder Content on the Recycling of Scrap Waste Tires)

  • 김진국;조하나;이수구
    • Elastomers and Composites
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    • 제29권5호
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    • pp.431-435
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    • 1994
  • For recycling of the waste tires, polyurethane binder mixed with the scrapped rubber powders which obtained from tread part of waste tire. This study covered the effect of the binder contents on the mechanical properties of the blend. We also studied the change of the properties after aging on properties compared with those of before aging. The curing reaction of the binder was also investigated in this study. We obtained conclusions the suitable binder content was 15phr in this system.

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철도차량용 유리섬유직물/페놀릭 복합재의 가속노화 특성 (Aging Characteristics of Glass Fabric/Phenolic Composites in Train Carbody)

  • 윤성호;남정표;황영은;신광복
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2004년도 춘계학술대회 논문집
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    • pp.352-357
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    • 2004
  • In this study. the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated through a 2.5KW accelerated environmental aging tester. Environmental factors such as temperature. moisture, and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile, bending, and shear specimens those are warp direction and fill direction were used to investigate the effects of environmental factors on mechanical properties of the composites. The glass fabric $\sharp$650/AP300 was used for the fabrication of specimens. Mechanical degradations for tensile, bending and shear properties were evaluated through a UTM. Also. storage shear modulus. loss shear modulus, and tan $\delta$ were measured as a function of exposure times through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using II scanning electron microscope.

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미생물 종별 특성과 토양에 장기간 노출된 화합물들의 Bioavailability와의 상관 관계 (Microbial Properties Influencing The Bioavailability of Aged Chemical in Soil.)

  • 박성희;조재경;이남영
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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    • pp.137-141
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    • 1998
  • A chemical has been aging in soil environment is more less bioavailable than freshly added chemical. The amount of bioavailability of the aged chemical is different by bacterial strains. The difference could be depend on physiochemical properties of each strain. Phenanthrene was employed as an aged chemical. Seven bacteria were isolated from activated sludge and petroleum disposed soil. These strains were able to degrade phenanthrene and to grow using phenanthrene as a sole carbon source. According to the result of materialization and chemical extraction experiment, the bioavailable amount of aged phenanthrene which has been aged in Lima loam is different by each bacteria. Several physiochemical properties of each strain were tested to certify correlation with their different amount of bioavailability.

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Zn-Pr-Co-Cr-Tb계 바리스터의 전기적 특성 및 안정성에 소결온도가 미치는 영향 (Effect of Sintering Temperature on Electrical Properties and Stability of Zn-Pr-Co-Cr-Tb-Based Varistors)

  • 남춘우
    • 한국재료학회지
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    • 제17권6호
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    • pp.298-302
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    • 2007
  • The electrical properties and its stability of Zn-Pr-Co-Cr-Tb-based varistors were investigated for different sintering temperatures. As the sintering temperatures increased, the varistor voltage decreased in the range of $705.2{\sim}299.1$ V/mm, the nonlinear coefficient decreased in the range of $42.4{\sim}31.7$, and the leakage current was in the range of $1.0{\sim}1.7\;{\mu}A$. The stability of electrical characteristics increased with the increase of sintering temperature. The varistors sintered at $1350^{\circ}C$ marked the high electrical stability, with $%\Delta$ $V_{1mA}=+0.1%,\;%\Delta{\alpha}=+3.2%$, and $%{\Delta}I_L=+117.6%$ for DC accelerated aging stress state of $0.95V_{1mA}/150^{\circ}C/24\;h$.

천연가황고무의 변형특성에 있어서 열경화의 영향 (The Effect of Heat Ageing Natural Vulcanized Rubber)

  • 강희진;김용덕;정현용;이태수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집A
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    • pp.309-314
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    • 2000
  • Rubber is used as a primary suspension component in a vehicle or a mechanical structure. The aim of this study is to establish a procedure for measuring the material properties of rubber and to analyze the differences of material properties of virgin rubber and heat aged rubber. The effect of mechanical conditioning was shown and included in the procedures of tensile. compression. simple shear. and pure shear tests. In addition. using engine oil was recommended for compression test in order not to have barrelling. Moreover, based on the material properties of vil·gin rubber and heat aged rubber. equations of C10 and IRHD were proposed as a function of heat aging temperature and time.

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Cr-Mo 강의 열화도 평가를 위한 Advanced Indentation System의 응용 (Application of Advanced Indentation System for Evaluati Tensile Property Degradation of Cr-Mo Steel)

  • 장재일;최열;이윤희;권동일;김정태
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집A
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    • pp.231-236
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    • 2001
  • A newly developed Advanced Indentation System (AIS), which is a portable and nondestructive system for evaluating tensile properties, was used to measure mechanical behavior of materials used under high temperature and pressure conditions. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. Aging effects of Cr-Mo and Cr-Mo-V steel at high temperature were simulated. Tensile properties including yield strength and tensile strength at various temperature are obtained from the test. For all test materials and conditions, the AIS-derived results were in good agreement with those from conventional standard test method. Examples of the test results ate given and potential applications of the AIS to assess the integrity of aging structures are briefly discussed.

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방사선조사에 따른 원전 저압케이블용 절연재료의 특성분석 (Characterization of Insulation Materials for Low Voltage Cables in a Nuclear Power Plant with ${\gamma}$-Ray Irradiation)

  • 박정기;이우선;한재홍
    • 한국전기전자재료학회논문지
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    • 제14권5호
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    • pp.397-404
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    • 2001
  • This study describes the effect of γ-ray irradiation on the properties of insulation materials for low voltage cables in a nuclear power plant. The radiation effects were characterized by measuring OIT, FTIR, electrical properties of the irradiated specimens. As a result, they showed the decrease of OIT and the increase of chemical structural defects with the increase of γ-ray amount. Also, the electrical properties such as dielectrical constant, tan $\delta$ and current were changed by aging. These changes may come from the increase of chemical structural defects by $\delta$-ray irradiation.

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Effect of Precured EPDM on the Property of Magneto-rheological Elastomer Based on NR/EPDM Blend

  • Na, Bokgyun;Chung, Kyungho
    • Elastomers and Composites
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    • 제53권2호
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    • pp.67-74
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    • 2018
  • Magneto-rheological elastomers (MREs) are smart materials in which the inherent stiffness and damping properties can be changed by the influence of an external magnetic field. The magneto-rheological (MR) effect depends on the orientation characteristics of the dispersed magneto-responsible particles (MRPs) in the matrix. In this study, natural rubber (NR) and ethylene propylene diene rubber (EPDM) were blended and used as a matrix of an MRE. EPDM was pre-cured before blending with NR. The Mooney viscosity, curing characteristics, and mechanical properties were analyzed with various pre-curing conditions of EPDM and the NR/EPDM blend. The results show that excellent mechanical properties of the NR/EPDM blend-based MRE were obtained when the pre-curing time of EPDM was 60 min. The aging property of the NR-based MRE was improved by the introduction of pre-cured EPDM. Also, the anisotropic MRE showed a higher MR effect than that of the isotropic MRE.

Silica와 Glass Fiber에 의한 Polychloroprene의 보강(補强) (Reinforcement of Polychloroprene by means of Silia and Glass Fiber)

  • 유종선;백남철
    • Elastomers and Composites
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    • 제23권3호
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    • pp.223-229
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    • 1988
  • The effect of triazine thiol derivative on the physical properties of silica-polychloroprene(CR) composites and glass fiber(MGF)-CR composites was investigated. Optimum cure time of the MGF composites filled with 2-dibuthylamino-4, 6-dithiol-s-triazine(DBT) was the fastest one, while maximum torque was the best in case of the silica composites filled with s-triazine-2,4,6-trithiol(TAT) on the Oscillating Disk Rheometer(ODR) test. Stress-strain curves of the composites showed that the physical properties such as 100% modulus, 300% modulus, tensile strength of the silica composites filled with DBT was very satisfactory and the silica composites filled with TAT was higher density of crosslinking than other crosslinked elastomer. In aging properties, elastomer filled DBT and TAT were progress post-curing reaction with increasing of aging time and it have been improved the tensile strength and crosslinking density.

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