• 제목/요약/키워드: DBU

검색결과 13건 처리시간 0.021초

반 잠수식 복수부선의 진수설계 (Development of float off Operation Design for Mdlti Semi-submersible Barges with Symmetrical Stability Casings)

  • 양영태;최문길;이춘보;박병남;성석부
    • 한국해양공학회지
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    • 제17권2호
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    • pp.72-76
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    • 2003
  • This paper presents the design concept and operation results of float-off for FSO (340,000 DWT Class, ELF AMENAM KPONO Project) built on the ground, without dry dock facilities. It was the first attempt to build FSO, completely, on the ground and launch it using DBU (Double Barge Unit, which was connected by rigid frame structure.) The major characteristics of FSO, which are similar to general VLCC type hull, including topside structure, weigh 51,000 metric ton. In order to have sufficient stability during the deck immersion of DBU, while passing through a minimum water plane area zone, proper trim control was completed with LMC (Load Master Computer). The major features of the monitoring system include calculation for transverse bending moment, shear force, local strength check of each connector, based on component stress, and deformation check during the load-out and float-off. Another major concern during the operation was to avoid damages at the bottom and sides of FSO, due to motion & movement after free-floating; therefore, adequate clearances between DBU and FSO were to be provided, and guide posts were installed to prevent side damage of the DBU casings. This paper also presents various measures that indecate the connector bending moment, damage stability analysis, and mooring of DBU during float off.

Synthesis, Characterization and Structure of DBU-hydrobromide-perbromide: A Novel Oxidizing Agent for Selective Oxidation of Alcohols to Carbonyl Compounds

  • Bakavoli, Mehdi;Rahimizadeh, Mohammad;Eshghi, Hossein;Shiri, Ali;Ebrahimpour, Zahra;Takjoo, Reza
    • Bulletin of the Korean Chemical Society
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    • 제31권4호
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    • pp.949-952
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    • 2010
  • A new and efficient reagent for the conversion of primary and secondary alcohols into their corresponding aldehydes and ketones is introduced. The reagent was easily prepared from the reaction of DBU with molecular bromine in $CHCl_3$. The structure of the reagent as $DBUH^+{Br_3}^-$ was determined by single crystal X-ray diffraction analysis.

Effects of Amine Catalysts on Structure of Polyurethane Foams

  • Furukawa, Mutsuhisa;Takamatsu, Katsuhiro
    • Elastomers and Composites
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    • 제34권4호
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    • pp.285-291
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    • 1999
  • Effects of catalysts on network structure, hard segment length and distribution of polyurethane foams in the absence of catalysts were investigated. CFC free all MDI-based poly urethane foams were prepared from poly(ethylene adipate)glycol, 4,4'-diphenylmethane diisocyanate, and water. Amino catalysts used were 1,4-diazabicyclo[2,2,2]octane(DABCO), N, N,N',N'-tetramethyl--hexane-1,6-diamine(MR), bis(2-methylamino ethyl)ether(ET), 1,8-diazabicyclo-[5,4,0]-undecene-7(DBU). Dibutyltindilaurate(DBTL) as control was also used. Hard segment components of polyurethane foams were obtained by a selective degradation of polyester chains with 0.01N KOH-methanol solution. The PUFs with DBU catalyst contained more amount of isocyanurate components than other PUFs. On the other hand, the PUFs with ET, MR, DBTL catalysts contained more amount of allophanate and biuret component than the other PUFs.

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Mechanism of Elimination from (E)-2,4-Dinitrobenzaldehyde O-pivaloyloxime Promoted by $R_2NH/R_2NH_2$+ buffer in 70% MeCN(aq)

  • 조봉래;조남순;정학석;손기남;한만소;편상용
    • Bulletin of the Korean Chemical Society
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    • 제18권12호
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    • pp.1301-1304
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    • 1997
  • Elimination reactions of (E)-2,4-dinitrobenzaldehyde O-pivaloyloxime promoted by R2NH/R2NH2+ buffer in 70% MeCN(aq) have been studied kinetically. The reaction exhibited second order kinetics and general base catalysis with Bronsted β=0.45. The Hammett ρ value decreased from 2.3 to 1.6 as the base-solvent system was changed from DBU in MeCN to R2NH/R2NH2+ buffer in 70% MeCN(aq). From these results an E2 mechanism is proposed.

수소이온 전도성 가교된 P(VDF-co-CTFE)-MAA/SEMA 막 제조 및 분석 (Preparation and Characterization of Proton Conducting Crosslinked P(VDF-co-CTFE)-MAA/SEMA membranes)

  • 라즈쿠마 파텔;증효뢰;허성연;김종학
    • 멤브레인
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    • 제23권4호
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    • pp.290-296
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    • 2013
  • 촉매 1,8-diazabicyclo[5,4,0]undec-7-ene(DBU)를 이용하여, poly(vinylidenefluoride-co-chlorotrifluoroethylene) P(VDF-co-CTFE) 고분자와 methacrylic acid (MAA)를 반응시켜, P(VDF-co-CTFE)-MAA 공중합체를 제조하였다. 또한 P(VDF-co-CTFE)-MAA와 2-sulfoethyl methacrylate (SEMA) 단량체를 4',4'-azobis(4-cyanovaleric acid) (ACVA) 개시제 하에서 자유 라디칼 중합하여 수소 이온 전도성 막을 제조하였다. SEMA 함량이 많아짐에 따라 술폰산 그룹이 증가하였다. SEMA 함량이 50%일 때 최대 이온교환 용량값이 0.82 meq/g에 도달하였으며 이는 함수량 결과와 일치하였다. 또한, SEMA 함량이 50%일 때 수소이온 전도도가 0.041 S/cm까지 도달하였다. 이러한 결과는 분리막에서 SEMA 함량이 증가할수록 수소 이온을 전달시킬 수 있는 이온그룹이 증가하기 때문이다.

프탈로시아닌 유도체 합성 및 광학응답특성 연구

  • 이준희;;손영아
    • 한국염색가공학회:학술대회논문집
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    • 한국염색가공학회 2011년도 제44차 학술발표회
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    • pp.67-67
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    • 2011
  • Recently, Phthalocyanine dye has attentions due to their excellent photochemical properties and used to optical applications such as chemical sensors. And azo groups can change photochemical properties in the UV irradiation because their molecualr structure reverse cis-trans isomer and changes cooperative motion, aggregation and so on. In this study, we synthesized the azo compound between amino pyridine and phenol. this azo derivative used the combination with 3-nitro phthalonitrile and makes phthalocyanine structure through the synthesis with 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU), zinc acetate. Finally, we synthesized a new photoswiching dye zinc-phthalocyanine azo compound. This compound was studied by phothoswichiing phenomenon by UV irradiation and analyzed molecular aggregation through the SEM images.

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