Design of Supramolecular Electrolytes for Solid State Dye-sensitized Solar Cells

고종관(Koh, Jong-Kwan),고주환(Koh, Joo-Hwan),서진아(Seo, Jin-Ah),김종학(Kim, Jong-Hak) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.06

Solid-state dye-sensitized solar cells (DSSCs) have been constructed employing supramolecular electrolytes with multiple hydrogen bonding. A supramolecule was facilely synthesized by one-pot reaction between the amines of methyl isocytosine (MIC) and the epoxy groups of poly(ethylene glycol diglycidyl ether) (PEGDGE) to produce quadruple hydrogen bonding units. Hydrogen bonding interactions and dissolution behavior of salt in supramolecular electrolytes are investigated. The ionic conductivity of the supramolecular electrolytes with ionic liquid, i.e. 1-methyl-3-propylimidazolium iodide (MPII) reaches 8.5{times}10^{-5} S/cm at room temperature, which is higher than that with metal salt (KI). A worm-like morphology is observed in the FE-SEM micrographs of TiO₂ nanoporous layer, due to the connection of TiO₂ nanoparticles resulting from adequate coating by electrolytes. DSSCs employing the supramolecular electrolytes with MPII and KI exhibit an energy conversion efficiency of 2.5 % and 0.5 %, respectively, at 100 mW/cm², indicating the importance of the cation of salt. Solar cell performances were further improved up to 3.7 % upon introduction of poly(ethylene glycol dimethyl ether) (PEGDME) with 500 g/mol.

정상 한국인 및 저식염식인에서 본 이뇨제투여후의 Renin-Angiotensin-Aldosterone 계

성호경,고주환,Sung, Ho-Kyung,Koh, Joo-Hwan 대한생리학회 1974 대한생리학회지 Vol.8 No.1

This study was carried out to investigate the acute changes in R-A-A system following lasix administration, and to evaluate the materials in plasma R-A-A system and electrolytic excretion every 30 minutes for 2 hours after lasix administration with normal high sodium Korean food, moderate sodium restriction, and severe sodium restriction, and it was concluded as followed; 1. Plasma renin activity, angiotensin II concentration, and aldosterone concentration elevated in course of time after lasix administration with high sodium Korean food, but the R-A-A system takes insignificant part because of the increasing rate was so slight. 2. Although the increasing rate of plasma renin activity reached lower levels, angiotensin II and aldosterone concentration were significantly increased after lasix administration with moderate sodium restriction. 3. It was observed that higher rise in aldosterone concentration following lasix administration during severe sodium restriction than when moderate sodium restriction. 4. Urinary sodium and potassium excretion during two hours after lasix administration showed decrease as little as the amount of sodium intake, but K/Na excretion ratio showed increase with small amount of sodium intake because of the decreasing rate of potassium was low value. 5. Sodium excretion after lasix administration reached more than 1.5 times of sodium intake, even though R-A-A reaction showed significantly. 6. As our results showed, R-A-A reaction following acute diuresis was insignificant with high sodium Intake, the increasing ratio of aldosterone concentration showed high rise compare with of plasma renin activity as little as the amount of sodium intake, and the participated rate in sodium reabsorption of R-A-A system was increased.

Crosslinked Composite Polymer Electrolyte Membranes Based On Diblock Copolymer and Phosphotungstic Acid

김종학,고주환,박정태,서진아,김종화,조영충,Kim, Jong-Hak,Koh, Joo-Hwan,Park, Jung-Tae,Seo, Jin-Ah,Kim, Jong-Hwa,Jho, Young-Choong The Membrane Society of Korea 2008 멤브레인 Vol.18 No.2

Proton conductive hybrid nanocomposite polymer electrolyte membranes comprising polystyrene-5-poly (hydroxyethyl methacrylate) (PS-b-PHEMA), sulfosuccinic acid (SA) and phosphotungstic acid (PWA) were prepared by varying PWA concentrations. The PHEMA block was thermally crosslinked by SA via the esterification reaction between -OH of PHEMA and -COOH of SA. Upon the incorporation of PWA into the diblock copolymer, the symmetric stretching bands of the $SO_3^-$ group at $1187cm^{-1}$ shifted to a lower wavenumber at $1158cm^{-1}$, demonstrating that the PWA particles strongly interact with the sulfonic acid groups of SA. When the concentration of PWA was increased to 30wt%, the proton conductivity of the composite membrane at room temperature increased from 0.045 to 0.062 S/cm, presumably due to the intrinsic conductivity of the PWA particles and the enhanced acidity of the sulfonic acid in the membranes. The membrane containing 30wt% of PWA exhibited a proton conductivity of 0.126 S/cm at $100^{\circ}C$. Thermal stability of the composite membranes was also enhanced by introducing PWA nanoparticles. 폴리스티렌-블록-폴리히드록에틸 메타크릴레이트(PS-b-PHEMA), 술포석시닉산(SA), 인텅스텐산(PWA)으로 구성된 수소 이온 전도성 나노복합 고분자 전해질막을 제조하였다. 폴리히드록에틸 메타크릴레이트(PHEMA) 블록의 히드록실그룹(-OH)와 술포석시닉산(SA)의 -COOH 그룹과의 에스테르 반응에 의하여 전해질막을 가교시켰다. 폴리헤테로산(PWA)을 도입했을 때, $SO_3^-$ 그룹의 신축 밴드가 $1187cm^{-1}$에서 $1158cm^{-1}$로 낮아졌으며, 이는 PWA 입자가 전해질막의 술폰산 그룹과 상호작용함을 나타낸다. PWA 함량이 30wt%가 되었을 때, 상온 전도도는 0.045에서 0.062S/cm로 증가되었으며, 이는 PWA 입자의 고유 전도도 특성과 전해질막의 술폰산기의 산도가 증가했기 때문이다. 또한 30wt%를 함유한 복합 전해질막은 $100^{\circ}C$에서는 최대 0.126 S/cm의 수소 이온 전도도를 나타내었다 PWA가 첨가됨에 따라 복합 전해질막의 열적특성 또한 증가하였다.

Preparation of Poly(vinyl chloride)-graft-poly(styrene sulfonic acid) Composite Nanofiltration Membranes

김종학,박정태,고주환,노동규,서진아,Kim, Jong-Hak,Park, Jung-Tae,Koh, Joo-Hwan,Roh, Dong-Kyu,Seo, Jin-Ah The Membrane Society of Korea 2008 멤브레인 Vol.18 No.2

Nanofiltration membranes were prepared based on coating a sulfonated comb-like copolymer layer on top of a poly(vinylidene fluoride) (PVDF) support. The comb-like copolymer comprising poly(vinyl chloride) backbone and poly(styrene sulfonic acid) side chains, i.e. PVC-g-PSSA was synthesized by atom transfer radical polymerization (ATRP) using direct initiation of the secondary chlorines of PVC. The successful synthesis of graft copolymers were confirmed by nuclear magnetic resonance ($^1H$-NMR), FT-IR spectroscopy and wide angle X-ray scattering (WAXS). Composite nanofiltration membranes consisting PVC-g-PSSA as a top layer exhibited the increase of both rejections and solution flux with increasing PSSA concentration. This performance enhancement is presumably due to the increase of SO3H groups and membrane hydrophilicity. The rejections of composite membranes containing 71 wt% of PSSA were 88% for $Na_2SO_4$ and 33% for NaCl, and the solution flux were 26 and $34L/m^2h$, respectively, at 0.3 MPa pressure. 폴리비닐리덴플로라이드(PVDF) 지지체 위에 빗살모양의 술폰화된 공중합체를 코팅하여 나노 분리막을 제조하였다. 빗살모양의 공중합체는 원자전달 라디칼 중합법(ATRP)에 의해 제조하였으며, 폴리비닐클로라이드의 주사슬과 폴리스티렌 술폰산(PSSA)의 곁사슬로 구성되어 있다. 핵자기 공명법($^1H$-NMR), FT-IR분광학 그리고 WAXS 분석법에 의해 공중합체가 성공적으로 합성되었음을 확인하였다 PVC-g-PSSA로 구성된 복합 나노 분리막은 PSSA의 함량이 증가함에 따라 플럭스와 배제율 모두 증가하였다. 이러한 성능 향상은 분리막의 술폰산의 함량의 증가로써 설명할 수 있다. PSSA가 71wt%첨가된 나노 복합막의 배제율은 $Na_2SO_4$ 88%, NaCl 33%을 나타내었고, 플럭스는 $Na_2SO_4$ 26, NaCl $34L/m^2 h$을 각각 나타내었다.

Synthesis of Organized TiO₂ Electrodes Using Graft Copolymer and Their Applications to Dye-Sensitized Solar Cells

안성훈(Ahn, Sung Hoon),고주환(Koh, Joo Hwan),박정태(Park, Jung Tae),김종학(Kim, Jong Hak) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06

The morphology of mesoporous TiO₂ films plays an important role in the operation of a DSSC. For example, the energy conversion efficiency of DSSCs with well-organized mesoporous TiO₂ films is much higher than those with traditional films possessing a random morphology. In previous research, well-organized mesoporous TiO₂ films have mainly been synthesized using an amphiphilic block copolymer, e.g., a poly(ethylene oxide) (PEO)-based template. A graft copolymer is more attractive than a block copolymer due to its low cost and the ease with which it can be synthesized. In this work, we provide the first report on the successful synthesis of well-organized mesoporous TiO₂ films templated by an organized graft copolymer as a structure directing agent. Well-organized mesoporous TiO₂ films with excellent channel connectivities were developed via the sol gel processusing an organized PVC-g-POEM graft copolymer synthesized by one-pot ATRP. The careful adjustment of copolymer composition and solvent affinity using a THF/H₂O/HCl mixture was used to systematically vary the material structure. The influence of the material structure on solar cell performance was then investigated. A solid-state DSSC employing both the graft copolymer templated organized 700 nm-thick TiO₂ films and graft copolymer electrolytes exhibited a solar conversion efficiency of 2.2% at 100 mW/cm². This value was approximately two-fold higher than that attained from a DSSC employing a random mesoporous TiO₂ film. The solar cell performance was maximized at 4.6% when the film thickness was increased to 2.5{mu}m. We believe that this graft copolymer-directed approach introduces a new and simple route toward the synthesis of well-organized metal oxide films as an alternative to a conventional block copolymer-based template.

Preparation of Anhydrous Crosslinked Graft Copolymer Electrolyte Membrane

노동규(Roh, Dong-Kyu),고주환(Koh, Joo-hwan),박정태(Park, Jung-tae),서진아(Seo, Jin-ah),김종학(Kim, Jong-hak) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.06

A comb-like copolymer consisting of a poly(vinylidene fluoride-co-chlorotrifluoro-ethylene) backbone and poly(hydroxy ethyl acrylate) side chains, i.e. P(VDF-co-CTFE)-g-PHEA, was synthesized through atom transfer radical polymerization (ATRP) using CTFE units as a macroinitiator. Successful synthesis and a microphase-separated structure of the copolymer were confirmed by proton nuclear magnetic resonance (1H-NMR), FT-IR spectroscopy, and transmission electron microscopy (TEM). This comb-like polymer was crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via the esterification of the -OH groups of PHEA and the -COOH groups of IDA. Upon doping with phosphoric acid (H₃PO₄) to form imidazole-H₃PO₄ complexes, the proton conductivity of the membranes continuously increased with increasing H₃PO₄ content. A maximum proton conductivity of 0.015 S/cm was achieved at 120?C under anhydrous conditions. In addition, these P(VDF-co-CTFE)-g-PHEA/IDA/H₃PO₄ membranes exhibited good mechanical properties (765 MPa of Young's modulus), and high thermal stability up to 250?C, as determined by a universal testing machine (UTM) and thermal gravimetric analysis (TGA), respectively.

Furosemide 이뇨중의 내당능 및 Insulin 반응에 미치는 K 또는 Ca 보충투여의 영향

성호경(Sung, Ho-Kyung),고주환(Koh, Joo-Hwan),유용운(Ryu, Yong-Woon) 대한생리학회 1976 대한생리학회지 Vol.10 No.2

Effect of furosemide administration on glucose tolerance, insulin-and HGH response following parenteral glucose loading was studied in healthy subjects. Effects of potassium or calcium on the furosemide induced changes were also observed in the same subjects. Furosemide administration resulted in a considerable reduction in the magnitude and duration of insulin response although no obvious changes were observed in glucose disappearance from the circulation. Oral potassium or calcium supplement to the furosemide treated subjects showed a reversion toward normal of the insulin response. The author suggested that a decreased endogenous insulin production resulting from the potassium and/or calcium depletion is responsible for the changes observed. In those subjects who receive parenteral nutrition if administration of furosemide is essential, it should be supplemented by potassium and/or calcium.

The cytokinesis-block micronucleus assay as a biological dosimeter in irradiated lymphocyte : Comparison of the response of mouse and human

김성호,조철구,김태환,류성렬,고경환,윤형근,고주환,최수용,Kim, Sung-ho,Cho, Chul-koo,Kim, Tae-hwan,Yoo, Seong-yul,Koh, Kyoung-hwan,Yun, Hyong-geun,Koh, Joo-hwan,Choi, Soo-yong The Korean Society of Veterinary Science 1993 大韓獸醫學會誌 Vol.33 No.3

정상인 말초혈액임파구 및 C57BL/6마우스 비장임파구에 $^{60}Co{\gamma}-rays$를 in vitro상태에서 조사한 후 500개 또는 1000개의 cytokinesis-blocked(CB) lymphocytes의 미세핵(micronuclei)의 발생빈도를 측정하였다. 방사선조사량에 따라 미세핵의 발생빈도는 증가하였으며 linear-quadratic model로 측정한 결과 선량반응곡선의 식은 인체의 경우 $Y=(0.31{\pm}0.049)D+(0.0022{\pm}0.0002)D^2+13.19$($r^2=1.000$)이었으며, 마우스의 경우 $Y=(1.31{\pm}0.264)D+(0.0015{\pm}0.0006)+8.7$($r^2=0.988$)이었다(Y는 1000개의 CB cell 당 미세핵발생빈도, D는 cGy로 표시되는 조사선량). 인체 말초혈액임파구에 대한 마우스 비장임파구의 상대적 생물학적 효과(relative biological effectiveness)는 미세핵의 발생율이 세포당 0.05~0.8의 범위에서 $1.84{\pm}0.48$이었다. 미세핵분석법은 인체 및 동물의 방사선 피폭시 간편하고 빠른 생물학적 선량측정법으로 사용될 수 있을 것이다.

Furosemide 투여후 Aldosterone 분비율의 변동

고주환,유용운,성호경 대한핵의학회 1976 핵의학 분자영상 Vol.10 No.1

정상 혈압을 유지하고 있는 건강한 청년을 대상으로 furosemide 이뇨기간중과 이뇨후 1일간의 aldosterone 분비율, 배설율 및 혈중농도를 측정하여 아래와 같은 성적을 얻었다. 1) Furosemide 투여후 2시간 동안의 aldosterone 배설량은 투여를 받지 않은 사람에 비하여 현저히 증가하였다. 2) Furosemide 투여후 뇨중으로의 Na 및 K 배설량은 모두 현저히 증가하였다. 3) Furosemide 이뇨기간중의 뇨증 배설 증가량은 심히 증가되었으나 aldosterone 분비율은 훨씬 미급하였다. 4) Furosemide 이뇨후 1일간의 aldosterone 배설은 별다른 변동을 보이지 않았고 분비율 변동도 크지는 않았지만 1일동안의 총분비량 증가분은 이뇨로 잃은양을 보충할만한 분량이었다. 5) 이상 성적으로 보아 aldosterone 분비를 증가하는데 양적 한계가 있는 것으로 보였으나 이를 해명하기 위하여는 대사성 제거율 측정이 있어야 할 것으로 고찰되었다. Marked augmentation of urinary aldosterone excretion following furosemide adnainistration was observed in previous experiment. In this study, author measured the changes of aldosterone secretion after furosemide administration in normotensive young volunteers with high sodium intake. After intraveeous injection of 1.2-3H-aldosterone, urine samples were collected in course of time until 24 hours after the injection. Furosemide administration was done at 30 minutes prior to aldosterone injection. Specific activities of 3H-aldosterone during and after diuresis were measured and aldosterone secretion rates were calculated dividing the doses by specific activities. Results were as followed. 1) Furosemide resulted in a marked increase in urinary aldosterone excretion. 2) Furosemide lead to an increase in both sodium and potassium excretion. 3) Aldosterone secretion rate was also inc rease d during furosemide diuresis, but the rate was smaller than that of urinary excretion. 4) Continuous modest increase in aldosterone secretion rate was shown after diuresis and tota1 excess amount of aldosterone secretion for 24 hrs was equivalent to the amount of aldosterone excretion produced by diruesis. 5) Abrupt marked loss of circulating aldosterone produced by diuresis was supplemented by long lasting increase in secretion for over twenty four hours.

Na 섭취제한,K 투여 및 이뇨 기간중 실혈성 Aldosterone 반응의 변동

고주환,유용운,이장규,성호경,박귀원 대한핵의학회 1977 핵의학 분자영상 Vol.11 No.1

고식염 섭취, Na 섭취제한, K 투여 및 이뇨기간중의 혈강 aldosterone 농도에 미치는 실혈의 영향을 정상 혈압을 유지하고 있는 청년 20명에서 관찰하여 아래와 같은 성적을 얻었다. 1) 실혈로 혈중 aldosterone 농도는 증가하였고 식염섭취제한이나 이뇨중의 실혈성 증가반응은 더욱 증대되었으나, K 투여로 aldosterone 농도가 이미 높은 개체에서는 증가반응을 가려낼 수 없었다. 2) 실혈시의 혈중 renin 활성도의 증가는 고식염식때 보다 Na 섭취제한이나 furosemide 이뇨시에 현저히 높았고 K 투여시의 실혈성 PRA 증가반응은 K를 별도로 투여치 않은 실험군과 별 변동이 없었다. 3) 실혈로 혈중 Na 농도에 큰 변동을 보이지 않았지만 모든 실험 조건하에서 감소경향은 나타내고 있었다. 4) 이상의 성적으로 보아 실혈에 의한 혈중 aldosterone 농도의 증가반응은 식염섭취제한이나 이뇨등의 부신 자극 요인이 있는 경우에 renin-aldosterone계의 활동 증가를 통한 aldosterone 분비의 가중현상을 보이나 K 섭취로 aldosterone 분비가 왕성한 기간중에는 실혈에 의한 renin 계의 aldosterone분비자극 첨가는 회의적이었다. Effect of sodium restriction with or without potassium supplement and furosemide diuresis on plasma aldosterone response to mild hemorrhage wese studied in normotensive young volunteers. After an overnight fast, blood were drawn just before and 10, 20, 30, 50, 70, 90, and 120 minutes after the 3H-aldosterone injection. The sum of blood delivered reached over 100ml (during two hours). Plasma aldosterone and renin were measured by means ot radioimmunoassay. The results were as followed; 1) Hemorrhage resulted in a moderate increase in plasma aldosterone level of volunteers with normal diet. 2) The mean figures of plasma aldosterone in subjects with sodium restriction and diuresis were likewise significantly increased by hemorrhage, however, the figure of the subjects with potassium supplement who already shown higher plasma level was without effect on hemorrhage. 3) Hemorrhage produced slight decrease in serum sodium concentration in every experimental conditions, although the changes were not significant. 4) Plasma renin activities after the hemorrhage followed a similar pattern with that of aldos terone, increased during sodium restriction cr diuresis and unaffected during potassium supplement. $quot;