• 제목/요약/키워드: inorganic content

검색결과 834건 처리시간 0.028초

Chemical Properties of Artificially Buried Wood in an Intertidal Zone during the Deterioration Period

  • SEO, Sujin;KIM, Taekjoon;LEE, Jae-Won
    • Journal of the Korean Wood Science and Technology
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    • 제48권6호
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    • pp.896-906
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    • 2020
  • Wood deterioration experiments were carried out for 6 months in an intertidal zone of South Korea to monitor the changes in the chemical properties of two types of species, Korean red pine and sawtooth oak. The results of FT-IR spectra and XRD patterns have shown that the chemical properties of the wood did not change significantly during the 6-month burial period. However, the brightness of the surface decreased after burial; the value of the sawtooth oak sample was lower than that of the Korean red pine sample owing to an accumulation of inorganic compounds in cell lumen as observed by ICP analysis. Among the inorganic compounds, sodium and sulfur concentrations increased significantly over the burial period compared with the control. Further, the maximum moisture content decreased from 199% to 136% in the Korean red pine and 62% to 60% for the sawtooth oak. Nevertheless, the major chemical composition of both the wood species did not change significantly during the 6-month burial period, whereas, the crystallinity decreased with an increasing burial period owing to an accumulation of inorganic compounds in the lumen.

SHS법에 의한 탄화텅스텐 분말 합성 (Synthesis of Tungsten Carbide Powders by SHS Method)

  • 전호병;조덕호;이형복;박성
    • 한국세라믹학회지
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    • 제31권10호
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    • pp.1159-1168
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    • 1994
  • We powders were synthesized from W powders in differnet particle sizes by Self-propagating High-temperature Synthesis process (SHS) using a chemical furnace. The effects of the mole ratio of chemical fuel content, pellet thickness and the mole ratio between carbon and tungsten (C/W Ratio) on synthesis were investigated with the tungsten powders have different particle size each other. Compositional and structural characterization of these powders was carried out by scanning electron microscope (SEM0 and x-ray diffractometer. Powder characterization was carried out by the measurement of particle size distribution with laser-particle size analyzer. The amounts of WC obtained by SHS process depend very much on the particle size of tungsten powder and heat contents given in a product, i.e. as the particle size of W powder is smaller, the amounts of WC produced increase. Also the more heat contents is given, the more amounts of WC increase. By optimizing the synthesis conditions, it is possible to fabricate WC powders which have little secondary phases (W2C, C).

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Sol-Gel 하드 코팅 막에서의 Spiropyran의 광 변색 특성 (Photochromic Properties of Spiropyran in Hard Coating Films Made by Sol-Gel Method)

  • 정상혁;조경인;박정용;송기창
    • Korean Chemical Engineering Research
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    • 제46권2호
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    • pp.310-315
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    • 2008
  • 실란커플링제인 glycidoxypropyl trimethoxysilane(GPTMS)과 vinyltriethoxysilane(VTES)을 출발물질로 하여 sol-gel 법에 의해 유-무기 혼성 용액을 제조하였다. 이 용액에 spiropyran계 광 변색 염료를 ethylacetate에 용해시킨 용액을 혼합하여 광 변색 코팅 용액을 제조하였다. 그 후 기재인 polycarbonate 시트에 스핀 코팅 시키고 $100^{\circ}C$에서 2 h 동안 열 경화시켜 광 변색성을 갖는 하드 코팅 막을 제조하였다. 코팅 막은 UV 광을 조사함에 의해 투명색으로부터 푸른색으로 변했다가 다시 투명색으로 변하는 가역적인 색변화를 보여주었다. 이때 코팅 막의 소색속도 및 연필경도는 코팅 용액 중의 GPTMS의 mol비가 증가됨에 따라 증가하였다.

헤어리베치(Vice villosa Roth) 품종별 국내 월동성, Biomass 및 무기태 질소 함량비교 (Comparison of Overwintering, Biomass, Inorganic N Concentration in Hairy Vetch (Vice villosa Roth) Cultivars)

  • 이상민;이연;이용환;성좌경;윤홍배;최현석
    • 한국유기농업학회지
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    • 제21권1호
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    • pp.61-68
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    • 2013
  • 헤어리베치 8종의 품종별 국내 적응성 검증을 위해 월동률과 biomass, 그리고 토양 중 무기태질소를 조사하였다. 겨울철 월동 후 생존율은 Hungvillosa와 Ostsaat 품종에서 좋았고, Minnie, Oregon common과 TTF1에서 낮았다. 생존율은 biomass에도 영향을 주어서 Hungvillosa와 Ostsaat 품종에서 가장 높았다. 헤어리베치 품종 간 무기성분 농도는 별다른 차이가 관찰되지 않았다. 토양 중 무기태질소 농도는 질소환원능이 좋았던, Hungvillosa와 Ostsaat가 예초 후 10여일 후에 크게 증가시켰다.

Crystal growing of NaX type zeolite

  • Ha, Jong-Pil;Seo, Dong-Nam;Jung, Mi-Jeong;Moon, In-Ho;Cho, Sang-Joon;Park, Hyun-Min;Kim, Ik-Jin
    • 한국결정성장학회지
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    • 제9권4호
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    • pp.371-376
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    • 1999
  • A large NaX type zeolite crystal of a uniform particle size of 20$\mu\textrm{m}$ are grown with various {{{{{H}_{2}O}}}} content by hydrothermal reaction and added seed crystal (2~3$\mu\textrm{m}$) to reactant solution as a function of different adding seed levels from 3 to 15%. The result that increased purity of NaX zeolite above 95% and homogeneity of crystal size by increasing adding seed levels, also decreased crystallization time. It was explained that adding seed to synthesis solution leaded out increase of surface area for physical contact reaction and directed growth of seed crystal, so more rapid consumption of reaction gel as increase seeding levels.

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폴리에스터 필름의 광투과도 향상에 대한 연구 (Study on the Improvement of Light Transmittance of Polyester Film)

  • 김시민;박수영
    • 폴리머
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    • 제36권5호
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    • pp.662-667
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    • 2012
  • 평판 디스플레이에 사용되는 PET 필름의 광학적 특성을 알아보기 위하여 필름 표면 굴절률, 필름 표면조도 및 필름 내부입자가 광투과율에 미치는 영향을 알아 보았다. 필름표면에 굴절률이 낮은 코팅층을 형성함에 따라 필름의 광투과율이 향상되었고, 최대의 광투과율을 가지는 코팅두께가 있음을 확인하였다. 표면 거칠기의 영향에 대해서는 표면조도를 나타내는 Ra를 입사 파장의 1/4 이하로 조절한 경우 광손실이 발생되지 않았다. 필름 내 무기입자는 입사된 광의 흡수 및 산란을 발생시켜 광손실을 증가시켰다.

Preparation and Characterization of Hybrid Silica-Poly(ethylene glycol) Sonogel

  • Jung, Hwa-Young;Gupta, Ravindra K.;Seo, Dong-Won;Kim, Yoo-Hang;Whang, Chin-Myung
    • Bulletin of the Korean Chemical Society
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    • 제23권6호
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    • pp.884-890
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    • 2002
  • An inorganic-organic hybrid system, silica-poly(ethylene glycol) songel is reported. This system was prepared via sol-gel method by varying varous processing variables. e.g. ultrasonic radiation time, gelling temperanture, PEG content and its molecular weight. Various experimental techniques wee employed to analyze the morphological, mechanical and optical properties of the system. The results were discussed in the light of existing theories. The sonogel system exhibited the common features of inorganic-organic hybrids. $SiO_2-10$ wt% PEG sonogel exhibited the morphological and optical properties superior to those reported earlier for the classic gels and found suitable for device applications.

Tribological Behaviour of the Si/SiC and the Si/SiC/Graphite Composites

  • Kim, In-Sub;Shin, Dong-Woo;So, You-Young;Lee, Byung-Ha
    • The Korean Journal of Ceramics
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    • 제3권1호
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    • pp.47-51
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    • 1997
  • The dense sintered bodies of Si/SiC composite with various Si contents could be fabricated by changing the green density in the forming process. The Si/SiC/graphite composites with various graphite contents could be also fabricated by changing a graphite content in the starting composition. Their mechanical and tribological properties were characterized and wear mechanism was also studided. The hardness and strength of the Si/SiC and the Si/SiC/graphite were decreased with increasing the contents of free Si and graphite, respectively. However, the friction coefficient and specific wear rate had no specific relations to their hardness and strength. Adhesion of free Si was a main factor to determine a wear resistance of the Si/SiC composite. In the case of the Si/SiC/graphite, solid lubricationl and liquid reservoir of the graphite particles played the main role of the reduction of the friction force. In the torque test to estimate the possibility of practical of practical applications, the value of torque between the Al2O3 disk and Si/SiC/graphite disk was 1/6 lower compared with two $Al_2O_3$ disks on the basis of 100,000 cycles.

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Sol-Gel법에 의해 Spiropyran을 함유한 광 변색 코팅 막의 제조 (Preparation of Photochromic Coating Films Containing Spiropyran by Sol-Gel Method)

  • 정상혁;조경인;송기창
    • Korean Chemical Engineering Research
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    • 제46권1호
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    • pp.112-117
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    • 2008
  • 1:1로 몰 비가 조절된 glycidoxypropyl trimethoxysilane(GPTMS)과 methyl triethoxysilane(MTES)을 출발물질로 하여 sol-gel법에 의해 유-무기 혼성 용액을 제조하였다. 이 용액에 spiropyran계 광 변색 염료를 ethylacetate(EA)에 용해시킨 용액을 혼합하여 광 변색 코팅 용액을 제조하였다. 그 후 기재인 polycarbonate 시트에 스핀 코팅 시키고 $100^{\circ}C$에서 2 h 동안 열 경화 시켜 광 변색 코팅 막을 제조하였다. 코팅 막은 UV 광을 조사함에 의해 가역적인 색변화를 보여주었다. 이때 코팅 막의 소색속도는 코팅 용액 중의 EA의 첨가량이 증가됨에 따라 증가하였다.

High Flame Retardancy and High-strength of Polymer Composites with Synergistically Reinforced MOSw and EG

  • Kim, Chowon;Lee, Jinwoo;Yoon, Hyejeong;Suhr, Jonghwan
    • Composites Research
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    • 제35권5호
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    • pp.359-364
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    • 2022
  • Polymers are inherently vulnerable to flame, which limits their application to various high-tech industries. In addition, environmental regulations restrict the use of halogen-based flame retardants which has best flame-retardant effect. There are inorganic flame retardants and phosphorous flame retardants as representative non-halogen-based flame retardants. However, high content of flame retardants is required to impart high flame retardancy of the polymers, and this leads to a decrease in mechanical properties. In this research, a new approach for inorganic flame retardant-based polymer composites with high mechanical properties and flame retardancy was suggested. Inorganic flame retardants called as magnesium oxysulfate whisker (MOSw) were used in this research. MOSw can extinguish fire by releasing water and non-combustible gases when exposed to flame. In addition, they have reinforcing effect when added into the polymer with its high aspect ratio. Expandable graphite (EG) was used as a flame-retardant supplement by helping to form a more dense char layer. Through this research, it is expected that it can be applied to various industries requiring flame retardancy such as automobile, and architecture by replacing halogen-based flame polymer composites.