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노환중,정인교,양동규,김태규,김종렬 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.3
Sonoring is caused by the repeated obstructions of versatile upper air way structure during sleep and is known as a kind of disease entity varing from simple snoring to obstructive sleep opnea syndrome(OSAS) which can cause serious cardiopulmonary complications due to its hypoxic pathophysiology. It has been reported that over 30% of middle-aged person have the problems of snoring and its accompanied symptomes and signs. Cephalometric measurements, frequently used to measure sella-nasion-subspinale(SNA) and sella-nasion-supramentale(SNB) angles, can provide the informations about the posterior airway space(PAS), the mandibular plane(MP) and the position of hyoid bone. These informations are useful in determining the therapeutic modalities of the snoring and OSAS patients. However, with conventional routine upright position, it does not represent the actual images of obstructive mechanism during sleep but only show the images of awaken normal upper airway anatomy. Therefore we have taken dual images of a routine upright lateral and a supine cephalometric view to compare both.
Roh, Dong Kyu,Ahn, Sung Hoon,Seo, Jin Ah,Shul, Yong Gun,Kim, Jong Hak Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of polymer science. Part B, Polymer physic Vol.48 No.10
<P>A novel graft copolymer consisting of a poly(vinylidene fluoride-co-chlorotrifluoroethylene) backbone and poly(glycidyl methacrylate) side chains, that is, P(VDF-co-CTFE)-g-PGMA, was synthesized through atom transfer radical polymerization (ATRP) using CTFE units as a macroinitiator. Successful synthesis and microphase-separated structure of the polymer were confirmed by <SUP>1</SUP>H NMR, FTIR spectroscopy, and TEM. As-synthesized P(VDF-co-CTFE)-g-PGMA copolymer was sulfonated by sodium bisulfite, followed by thermal crosslinking with sulfosuccinic acid (SA) via the esterification to produce grafted/crosslinked polymer electrolyte membranes. The IEC values continuously increased with increasing SA content but water uptake increased with SA content up to 10 wt %, above which it decreased again as a result of competitive effect between crosslinking and hydrophilicity of membranes. At 20 wt % of SA content, the proton conductivity reached 0.057 and 0.11 S/cm at 20 and 80 °C, respectively. The grafted/crosslinked P(VDF-co-CTFE)-g-PGMA/SA membranes exhibited good mechanical properties (>400 MPa of Young's modulus) and high thermal stability (up to 300 °C), as determined by a universal testing machine (UTM) and TGA, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1110–1117, 2010</P>
Roh, Dong Kyu,Chi, Won Seok,Ahn, Sung Hoon,Jeon, Harim,Kim, Jong Hak Wiley-VCH 2013 ChemSusChem Vol.6 No.8
<P>Herein, we report a facile synthesis of high-density anatase-phase vertically aligned thornbush-like TiO2 nanowires (TBWs) on transparent conducting oxide glasses. Morphologically controllable TBW arrays of 9 μm in length are generated through a one-step hydrothermal reaction at 200?C over 11 h using potassium titanium oxide oxalate dehydrate, diethylene glycol (DEG), and water. The TBWs consist of a large number of nanoplates or nanorods, as confirmed by SEM and TEM imaging. The morphologies of TBWs are controllable by adjusting DEG/water ratios. TBW diameters gradually decrease from 600 (TBW600) to 400 (TBW400) to 200 nm (TBW200) and morphologies change from nanoplates to nanorods with an increase in DEG content. TBWs are utilized as photoanodes for quasi-solid-state dye-sensitized solar cells (qssDSSCs) and solid-state DSSCs (ssDSSCs). The energy-conversion efficiency of qssDSSCs is in the order: TBW200 (5.2%)>TBW400 (4.5%)>TBW600 (3.4%). These results can be attributed to the different surface areas, light-scattering effects, and charge transport rates, as confirmed by dye-loading measurements, reflectance spectroscopy, and incident photon-to-electron conversion efficiency and intensity-modulated photovoltage spectroscopy/intensity-modulated photocurrent spectroscopy analyses. TBW200 is further treated with a graft-copolymer-directed organized mesoporous TiO2 to increase the surface area and interconnectivity of TBWs. As a result, the energy-conversion efficiency of the ssDSSC increases to 6.7% at 100 mW cm(-2) , which is among the highest values for N719-dye-based ssDSSCs.</P>
Roh, Dong Kyu,Seo, Jin Ah,Chi, Won Seok,Koh, Jong Kwan,Kim, Jong Hak The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.22
<P>Multi-functional mesoporous TiO<SUB>2</SUB> (M-TiO<SUB>2</SUB>) beads with high porosity and good interconnectivity in the anatase phase were synthesized <I>via</I> a solvothermal reaction at low temperature (100 °C) using a graft copolymer, <I>i.e.</I>, poly(vinyl chloride)-<I>g</I>-poly(oxyethylene methacrylate) (PVC-<I>g</I>-POEM), as a structure-directing agent. Field-emission scanning electron microscopy (FE-SEM), energy-filtering transmission electron microscopy (EF-TEM) and X-ray diffraction (XRD) revealed that the TiO<SUB>2</SUB> beads consisted of 13 nm interconnected nanocrystallites and were monodisperse with tunable sizes of approximately 120, 250, 500 and 750 nm. The photoelectrodes fabricated with M-TiO<SUB>2</SUB> beads showed a high surface area (86.5 m<SUP>2</SUP> g<SUP>−1</SUP>) and a stronger light scattering effect, as confirmed by Brunauer–Emmett–Teller (BET) and incident photon-to-electron conversion efficiency (IPCE) measurements. The structures of M-TiO<SUB>2</SUB> beads effectively offered better pore infiltration of the polymer electrolyte. Furthermore, the improved interconnectivity of M-TiO<SUB>2</SUB> beads improved the electron diffusion coefficient and electron lifetime, resulting in an improvement in the light harvesting efficiency. Thus, quasi-solid-state polymer electrolyte dye-sensitized solar cells (DSSCs) with M-TiO<SUB>2</SUB> beads showed a higher efficiency (4.8% at 100 mW cm<SUP>−2</SUP>) than those with conventional P25 (3.8%). A structure–property relation among M-TiO<SUB>2</SUB> beads was investigated in terms of surface area and light scattering. Upon utilizing double layer structures and a solid polymerized ionic liquid (PIL), the efficiency was increased up to 6.7% at 100 mW cm<SUP>−2</SUP>, one of the highest values for all-solid-state DSSCs.</P> <P>Graphic Abstract</P><P>Size-tunable, multi-functional mesoporous TiO<SUB>2</SUB> beads with high porosity and good interconnectivity in the anatase phase are synthesized <I>via</I> a solvothermal reaction using a graft copolymer as a structure-directing agent. The TiO<SUB>2</SUB> beads show a high surface area, greater light scattering effect, better pore-infiltration of electrolyte and improved electron lifetime. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm30826f'> </P>
Roh, Dong Kyu,Kim, Sang Jin,Jeon, Harim,Kim, Jong Hak American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.14
<P>Mesoporous MgTiO<SUB>3</SUB> perovskite with a high porosity and interfacial properties were synthesized via a solvothermal reaction at 150 °C for 10 h using a graft copolymer, i.e., poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) with a well-ordered micellar morphology as a structure-directing agent. A PVC-g-POEM graft copolymer with a wormlike morphology was utilized as a soft matrix to prepare a mixed matrix membrane (MMM) with mesoporous MgTiO<SUB>3</SUB> perovskite through a solution-casting method. The structure and morphology of PVC-g-POEM graft copolymer was carefully tuned by controlling polymer-solvent interactions, as characterized by transmission electron microscopy (TEM). The average pore diameter of the MgTiO<SUB>3</SUB> perovskite was 10.4 nm, which is effective in facilitating gas transport via Knudsen diffusion through mesopores as well as improving interfacial contact with the organic polymer matrix. Because of a high porosity (0.56), the density of mesoporous MgTiO<SUB>3</SUB> (1.75 g/cm<SUP>3</SUP>) was much lower than that of dense nonporous MgTiO<SUB>3</SUB> (4 g/cm<SUP>3</SUP>) and not significantly higher than that of PVC-g-POEM (1.25 g/cm<SUP>3</SUP>), leading to a uniform distribution of MgTiO<SUB>3</SUB> in MMM. The permeability of MMM with MgTiO<SUB>3</SUB> was greater than those of MMM with only MgO or TiO<SUB>2</SUB>, indicating the simultaneous improvement of solubility and diffusivity in the former, as supported by CO<SUB>2</SUB> temperature-programmed desorption (TPD) measurements. The MMM with MgTiO<SUB>3</SUB> 25 wt % exhibited a CO<SUB>2</SUB> permeability improvement of 140% up to 138.7 Barrer (1 Barrer = 1 × 10<SUP>–10</SUP> cm<SUP>3</SUP>(STP) cm cm<SUP>–2</SUP> s<SUP>–1</SUP> cmHg<SUP>–1</SUP>) without a large loss of CO<SUB>2</SUB>/N<SUB>2</SUB> selectivity.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-14/am401306p/production/images/medium/am-2013-01306p_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am401306p'>ACS Electronic Supporting Info</A></P>