Synthesis and properties of a polyhedral oligomeric silsesquioxane-based new light-emitting nanoparticle.

Eom, Jae-Hoon,Mi, Dongbo,Park, Moo-Jin,Cho, Hoon-Je,Lee, Jonghee,Lee, Jeong-Ik,Chu, Hye Yong,Shim, Hong-Ku,Hwang, Do-Hoon American Scientific Publishers 2009 Journal of nanoscience and nanotechnology Vol.9 No.12

<P>A polyhedral oligomeric silsesquioxane (POSS)-based electroluminescent nanoparticle, POSS-NPA, which contains anthracenenaphthyl chromophores on each of its eight arms, was easily prepared via the hydrosilylation reaction between octakis(dimethylsiloxy)silsesquioxane and allyl-functionalized 9-naphthalene-2-yl-10-phenyl anthracene chromophores. POSS-NPA was completely soluble in common organic solvents such as chloroform, THF, toluene, p-xylene, and chlorobenzene, and showed good film-forming properties on a quartz plate or an indium tin oxide (ITO) plate, i.e., it has good solution processing properties. The UV-visible absorption and the photoluminescence (PL) emission maxima of POSS-NPA in chlorobenzene solution were found to be 378 nm and 433 nm while those of POSS-NPA in the solid state were 379 and 464 nm, respectively. An electroluminescent (EL) device with the configuration of ITO/PEDOT:PSS/POSS-NPA (50 nm)/BAIq (40 nm)/LiF (1 nm)/Al (120 nm) was also fabricated and the blue light emission was successfully obtained.</P>

Green Light-Emitting Diodes from Poly(2-dimethyloctylsilyl-1.4-phenylenevinylene)

Do Hoon Hwang,Sung Tae Kim,Hong Ku Shim,Andrew B. Holmes,Richard H. Friend 한국고분자학회 1997 한국고분자학회 학술대회 연구논문 초록집 Vol.1997 No.4

VipD of <i>Legionella pneumophila</i> Targets Activated Rab5 and Rab22 to Interfere with Endosomal Trafficking in Macrophages

Ku, Bonsu,Lee, Kwang-Hoon,Park, Wei Sun,Yang, Chul-Su,Ge, Jianning,Lee, Seong-Gyu,Cha, Sun-Shin,Shao, Feng,Heo, Won Do,Jung, Jae U.,Oh, Byung-Ha Public Library of Science 2012 PLoS pathogens Vol.8 No.12

<▼1><P>Upon phagocytosis, <I>Legionella pneumophila</I> translocates numerous effector proteins into host cells to perturb cellular metabolism and immunity, ultimately establishing intracellular survival and growth. VipD of <I>L. pneumophila</I> belongs to a family of bacterial effectors that contain the N-terminal lipase domain and the C-terminal domain with an unknown function. We report the crystal structure of VipD and show that its C-terminal domain robustly interferes with endosomal trafficking through tight and selective interactions with Rab5 and Rab22. This domain, which is not significantly similar to any known protein structure, potently interacts with the GTP-bound active form of the two Rabs by recognizing a hydrophobic triad conserved in Rabs. These interactions prevent Rab5 and Rab22 from binding to downstream effectors Rabaptin-5, Rabenosyn-5 and EEA1, consequently blocking endosomal trafficking and subsequent lysosomal degradation of endocytic materials in macrophage cells. Together, this work reveals endosomal trafficking as a target of <I>L. pneumophila</I> and delineates the underlying molecular mechanism.</P></▼1><▼2><P><B>Author Summary</B></P><P><I>Legionella pneumophila</I> is a pathogen bacterium that causes Legionnaires' disease accompanied by severe pneumonia. Surprisingly, this pathogen invades and replicates inside macrophages, whose major function is to detect and destroy invading microorganisms. How <I>L. pneumophila</I> can be “immune” to this primary immune cell has been a focus of intensive research. Upon being engulfed by a macrophage cell, <I>L. pneumophila</I> translocates hundreds of bacterial proteins into this host cell. These proteins, called bacterial effectors, are thought to manipulate normal host cellular processes. However, which host molecules and how they are targeted by the bacterial effectors are largely unknown. In this study, we determined the three-dimensional structure of <I>L. pneumophila</I> effector protein VipD, whose function in macrophage was unknown. Ensuing analyses revealed that VipD selectively and tightly binds two host signaling proteins Rab5 and Rab22, which are key regulators of early endosomal vesicle trafficking. These interactions prevent the activated form of Rab5 and Rab22 from binding their downstream signaling proteins, resulting in the blockade of endosomal trafficking in macrophages. The presented work shows that <I>L. pneumophila</I> targets endosomal Rab proteins and delineates the underlying molecular mechanism, providing a new insight into the pathogen's strategies to dysregulate normal intracellular processes.</P></▼2>

단기부하예측을 위한 Takagi-Sugeno 퍼지 모델 기반 예측기 설계

김도완(Do Wan Kim),박진배(Jin Bae Park),장권규(Kwon Ku Jang),정근호(Kyun Ho Jung),주영훈(Young Hoon Joo) 한국지능시스템학회 2004 한국지능시스템학회 학술발표 논문집 Vol.14 No.1

This paper presents a new design methods of the short-term load forecasting system (STLFS) using the data mining. The proposed predictor takes form of the convex combination of the linear time series predictors for each inputs. The problem of estimating the consequent parameters is formulated by the convex optimization problem, which is to minimize the norm distance between the real load and the output of the linear time series estimator. The problem of estimating the premise parameters is to find the parameter value minimizing the error between the real load and the overall output. Finally, to show the feasibility of the proposed method, this paper provides the short-term load forecasting example.

Optical Third-Harmonic Generation of Poly(2-Bromo-1,4-phenylenevinylene)

Hwang Do-Hoon,Lee Jeong-Ik,Lee Minyung,Shim Hong-Ku Korean Chemical Society 1994 Bulletin of the Korean Chemical Society Vol.15 No.1

Weakly electron withdrawing bromine substituted poly(2-bromo-1,4-phenylenevinylene) (PBrPV) was synthesized th-rough water-soluble precursor method. The linear and nonlinear optical properties of PBrPV were compared with those of poly(1,4-phenylenevinylene) (PPV). The third-order nonlinear optical susceptibility, X^{(3)}$, was measured by using third-harmonic generation (THG) technique at 1907 nm, fundamental wavelength. The calculated $X^{(3)}$ values of PPV and PBrPV were 3${\times}$ 10$^{-12}$ esu and 2${\times}$10$^{-12}$ esu, respectively.

Synthesis and characterization of novel germanium-containing poly(p-phenylenevinylene) derivatives

Cho, Hoon-Je,Hwang, Do-Hoon,Lee, Jong-Don,Cho, Nam-Sung,Lee, Sang-Kyu,Lee, Jonghee,Jung, Young Kwan,Shim, Hong-Ku Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of polymer science Part A, Polymer chemist Vol.46 No.3

<P>Novel blue-emitting germanium-containing poly(p-phenylenevinylene) (PPV) derivatives with well-defined conjugation lengths were synthesized via Wittig-condensation polymerizations. The polymers can be color-tuned by the introduction of various chromophores into the PPV-based polymer backbones. The photoluminescence (PL) spectra of the polymers, GePVK (containing carbazole moieties), GeMEH (containing dialkoxybenzene moieties), and GePTH (containing phenothiazine moieties), were found to exhibit blue, greenish blue, and green emissions, respectively. GePTH produces more red-shifted emission than GeMEH and GEPVK, resulting in green emission, and the solution and solid state PL spectra of GePVK consist of almost blue emission. The electroluminescence spectra of GeMEH and GePTH contain yellowy green and yellow colors, respectively. Interestingly, GePVK exhibits white emission with CIE coordinates of (0.33, 0.37) due to electroplex emission in the light-emitting diodes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 979–988, 2008</P> <B>Graphic Abstract</B> <P>Three novel germanium-containing poly(p-phenylenevinylene) derivatives—GePVK, GeMEH, and GePTH—were successfully synthesized via Wittig-condensation polymerization. The polymers can be color-tuned by the introduction of various chromophores into the PPV-based polymer backbones. The photoluminescence spectra of the polymers, GePVK, GeMEH, and GePTH, were found to exhibit blue, greenish blue, and green emissions, respectively. <img src='wiley_img/0887624X-2008-46-3-POLA22441-gra001.gif' alt='wiley_img/0887624X-2008-46-3-POLA22441-gra001'> </P>

Synthesis and Electroconductivities of Poly(2-cyano-5-methoxyl-1,4-phenylenevinylene) and Copolymers

Hong-Ku Shim,Shin-Woong Kang,Do Hoon Hwang Korean Chemical Society 1993 Bulletin of the Korean Chemical Society Vol.14 No.1

Poly(2-cyano-5-methoxy-1,4-phenylenevinylene), PCMPV and a series of PPV copolymers containing 2-cyano-5-methoxy-1,4-phenylenevinylene (CMPV) units were prepared via the water-soluble precursor method. They were obtained in films form and were easily doped with $FeCl_3$. Doping of undrawn and drawn films of PCMPV homopolymer with $FeCl_3$ led to conductivity of $10^{-5}-10^{-4}\;Scm^{-1}$. Conductivity of $FeCl_3$-doped copolymer films ranged from $10^{-3}$ 4.0 Scm$^{-1}$ depending on composition. As the content of CMPV units in the copolymer increased further, the electrical conductivity steadly decreased. Electronic effect by the CN substituent and morphological changes brought by copolymerization appear to interplay intricately resulting in the observation of a maximum conducting composition.

Synthesis and characterization of fluorene-based copolymers containing siloxane or distilbene moieties on their main chain

Cho, Hoon-Je,Park, Moo-Jin,Hwang, Do-Hoon,Ahn, Taek,Hong, Ji-Won,Lee, Jonghee,Cho, Nam Sung,Shim, Hong-Ku Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science Part A, Polymer chemist Vol.47 No.6

<P>Two novel types of polyfluorene copolymers containing siloxane linkages or distilbene moieties on their main-chains were synthesized by Ni(0)-mediated Yamamoto coupling polymerization. These polymers, designated P2Silo05, P2Silo15, PF-P02, and PF-P05 were prepared by copolymerization between 2,7-dibromo-9,9′-dihexylfluorene and bis(bromobenzene)-terminated disiloxane monomer (for P2Silo05 and P2Silo15) or dibromodistilbene monomer (for PF-P02 and PF-P05). All of the polymers were highly soluble in common organic solvents such as chloroform, toluene, and p-xylene. The glass transition temperatures of the polymers were between 92 and 113 °C, and the decomposition temperatures for a 5% weight loss (T<SUB>d</SUB>) were above 420 °C for all of the polymers, demonstrating high thermal stability. The molecular weight (M<SUB>w</SUB>) of the polymers ranged from 4.2 × 10<SUP>4</SUP> to 8.8 × 10<SUP>4</SUP>. The blue shift of the maximum in the UV-visible absorption was greater in polymers with a higher molar percentage of siloxane linkages or distilbene moieties than in homo poly (dihexylfluorene) (PDHF). However, the photoluminescence spectra of the polymers were similar to those of PDHF in terms of the onsets and patterns. Single-layer light-emitting diodes were fabricated with a configuration of ITO/PEDOT:PSS/polymers/Ca/Al. The maximum electroluminescence emission wavelengths of the polymers were 425–450 nm, corresponding to pure blue light. The CIE co-ordinates of the polyfluorenes containing siloxane linkages or distilbene moieties ranged from (0.21, 0.21) to (0.17, 0.10), indicating deeper blue light than that of PDHF {CIE co-ordinates of (0.25, 0.29)}, with P2Silo15 giving the deepest blue-light {CIE co-ordinates of (0.17, 0.10)}. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1595–1608, 2009</P> <B>Graphic Abstract</B> <P>We have synthesized two types of polyfluorene copolymers containing siloxane linkages or distilbene moieties on their main-chains. To the best of our knowledge, P2Silo05 and P2Silo15 are the first polyfluorene copolymers that contain siloxane linkages on their main-chains. Interestingly, the CIE coordinates of the polyfluorenes containing siloxane linkages or distilbene moieties ranged from (0.21, 0.21) to (0.17, 0.10), indicating a deeper blue light emission than that of PDHF {CIE coordinates of (0.25, 0.29)}. <img src='wiley_img/0887624X-2009-47-6-POLA23259-gra001.gif' alt='wiley_img/0887624X-2009-47-6-POLA23259-gra001'> </P>

도시철도 이용 정보 전달을 위한 시각화 구현 방안에 대한 고찰

정구인(Ku-In Jung),김태도(Tae-Do Kim),김영수(Yong-Su Kim),이석흥(Suk-heoung Lee),주종훈(Jong-Hoon Joo),신민창(Min-Chang Shin),최시행(Si-Hang Choi),한창문(Chang-Mun Han) 한국철도학회 2015 한국철도학회 학술발표대회논문집 Vol.2015 No.5

A Preliminary Study on the Feasibility of Copper Mesh as an Off-Gas Iodine Capturing Medium for Pyroprocessing

Min Ku Jeon,Tae Kyo Lee,Yong Taek Choi,Hee-Chul Eun,Jung Hoon Choi,Hwan-Seo Park,Jin-Mok Hur,Do-Hee Ahn 한국방사성폐기물학회 2015 방사성폐기물학회지 Vol.13 No.3

본 연구에서는 파이로프로세싱에서 발생하는 배기체 내 요오드 포집을 위한 매질로서 고가의 은 기반 흡착제를 대체하기 위 한 상용 구리메쉬의 가능성에 대해 연구하였다. 열역학적 계산을 통해 구리 금속과 요오드 기체의 반응은 100 ~ 500℃ 온도 범위에서 자발적으로 일어나며 요오드화구리(CuI)를 형성할 것으로 예상되었다. 실험을 통해 반응 온도에 따른 요오드 포 집 효율의 영향을 분석한 결과, 1개의 구리메쉬(질량 0.26 g)를 이용하여 반응 온도를 300, 400℃로 변화하였을 때 각각 5 및 6 wt%의 요오드(초기질량 2.0 g)가 포집됨을 확인하였다. 또한, 반복 실험 결과를 토대로 구리메쉬 표면에 형성된 반응 생성 물(CuI)의 자발적인 탈리 현상으로 구리의 활용률이 증가할 수 있음을 확인하였다. 반응 생성물의 CuI 상 형성은 X-선 회절 실험을 통해 확인하였으며, 표면 분석은 주사전자현미경을 이용하여 수행하여 그 결과를 보고하였다. A commercially available copper mesh was investigated as an iodine off-gas capturing medium for pyroprocessing, with an aim to replace costly silver based adsorbents. Theoretical calculation results suggested that the reaction between metallic copper and gaseous iodine will occur spontaneously to produce copper iodide in the temperature range of 100 ~ 500℃. The effect of the reaction temperature on iodine capturing efficiency was investigated by experimentation, and it was found that 5 and 6 wt% of iodine (initial mass 2.0 g) was captured by a single copper mesh (0.26 g) at 300 and 400℃, respectively. The repeated experimental results also suggested that copper utilization can be increased with the help of the spontaneous detachment of the reaction product (CuI) from a copper mesh. The formation of the CuI phase was confirmed using the X-ray diffraction technique, and the surface morphology of the reaction product was observed using scanning electron microscopy.