• 제목/요약/키워드: inorganic chemical

검색결과 1,508건 처리시간 0.032초

해포석이 시멘트 경화체의 특성에 미치는 영향 (The Effects of Sepiolite on the Properties of Portland Cement Mortar)

  • 강현주;송명신;김영식
    • 한국세라믹학회지
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    • 제45권8호
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    • pp.443-452
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    • 2008
  • Shrinkage crack is a major concern for cement materials, especially for flat structures such as Korean On-Dol floor system, flooring for garages, and wall. One of the methods to reduce the adverse effects of shrinkage cracking is to reinforce cement materials with shot randomly distributed fibers. The efficiency of inorganic fibrous material to arresting cracks in cementitious composites was studied. Cement materials reinforced with five different qualities of inorganic fibrous material were tested. Contents of inorganic fibrous material were 1.0 kg, 1.5 kg, 2.0 kg, 2.5 kg, 3.0 kg by weight of cement mortar and C : S types of cement mortar were 1:3 and 1:4. W/C were 60% and 80%. Cement mortar of inorganic fibrous material reinforcement showed an ability to reduce the crack width and crack length significantly as compared to unreinforced cement mortar. $40%{\sim}60%$ drop in shrinkage crack of 1:4 cement mortar with 1.5 kg over was observed.

DMFC용 PVDF/SPEEK/TiO2 하이브리드 막의 수분함량과 메탄올 전이현상 (Liquid Uptake and Methanol Transport Behaviour of PVDF/SPEEK/TiO2 Hybrid Membrane for DMFC)

  • 유선경;김한주;박수길
    • 전기화학회지
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    • 제8권4호
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    • pp.177-180
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    • 2005
  • 유 무기 혼성 막의 계열은 티타니움 디옥사이드 나노파티클 함량의 체계적인 변화에 의해 조제된다. 유 무기 혼성 막의 수분함량, 메탄올 투과도와 전자 전도 특성은 무기 산화물의 함량의 기능에 따라 연구된다. 그 결과 망상구조의 무기 산화물은 전자 전도 특성과 수분함량의 감소를 보였다. 또한 무기 산화물의 함량이 증가할수록 메탄올 투과도도 감소함을 나타내었다. 형태학적인 관점에서 막은 폴리머 기반과 무기영역 사이에 균일하고 잘 점착됨을 보여준다. 혼성막의 특성은 나피온막과 비교 실험되었다.

Substantial Evidences Indicate That Inorganic Arsenic Is a Genotoxic Carcinogen: a Review

  • Roy, Jinia Sinha;Chatterjee, Debmita;Das, Nandana;Giri, Ashok K.
    • Toxicological Research
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    • 제34권4호
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    • pp.311-324
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    • 2018
  • Arsenic is one of the most toxic environmental toxicants. More than 150 million people worldwide are exposed to arsenic through ground water contamination. It is an exclusive human carcinogen. Although the hallmarks of arsenic toxicity are skin lesions and skin cancers, arsenic can also induce cancers in the lung, liver, kidney, urinary bladder, and other internal organs. Arsenic is a non-mutagenic compound but can induce significant cytogenetic damage as measured by chromosomal aberrations, sister chromatid exchanges, and micronuclei formation in human systems. These genotoxic end points are extensively used to predict genotoxic potentials of different environmental chemicals, drugs, pesticides, and insecticides. These cytogenetic end points are also used for evaluating cancer risk. Here, by critically reviewing and analyzing the existing literature, we conclude that inorganic arsenic is a genotoxic carcinogen.

전도체 형성 방법에 따른 유무기 복합재료 안테나의 고주파 특성 (Microwave Properties of Organic-inorganic Composite Material Antenna with Various Fabrication Method of Conduction Material)

  • 박상훈;성원모
    • 한국전기전자재료학회논문지
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    • 제19권9호
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    • pp.832-837
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    • 2006
  • Antennas were fabricated by physical(adhesive) and chemical(deposition+plating) method on organic-inorganic composite material. And antennas were measured dielectric constant and gain. Dielectric constant of antennas were fabricated by physical method was decreased with increase of adhesive tape thickness and number of conduction material composition. But antennas were fabricated by chemical method was reached to 90 % of dielectric material. Gain of antennas were fabricated by physical method was decreased with increase of adhesive tape thickness. But they were unrelated with conduction material composition. The other side antennas were fabricated by chemical method excelled more 0.8 dBic than antennas were fabricated by physical method in gain of antenna. Finally, chemical method can expect excellent product process because it can produce smaller size, higher gain and elimination of many handworks.

Preparation and Characterization of $TiO_2$Filled Sulfonated Poly(ether ether ketone) Nanocomposite Membranes for Direct Methanol Fuel Cells

  • Kim Han-Joo;Kalappa Prashantha;Son Won-Keun;Park Jong-Eun;Oshaka Tetsuya;Kim Hyun-Hoo;Hong Ji-Sook;Park Soo-Gil
    • KIEE International Transactions on Electrophysics and Applications
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    • 제5C권4호
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    • pp.165-170
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    • 2005
  • A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxide nanoparticle content. Their water uptake, methanol permeability and proton conductivity as a function of temperature were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of the morphology, membranes are homogeneous and exhibit good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with the standard nafion membrane.