Electrocatalytic activity of chemically deposited Cu_xS thin film for counter electrode in quantum dots-sensitized solar cells

Lim, I.,Lee, D.Y.,Patil, S.A.,Shrestha, N.K.,Kang, S.H.,Nah, Y.C.,Lee, W.,Han, S.H. Elsevier Science Publishers 2014 Materials chemistry and physics Vol.148 No.3

The compact (c-Cu<SUB>x</SUB>S) and the porous (p-Cu<SUB>x</SUB>S) with particle decorated films of coppers-ulfidearesynthesized using a chemical bath deposition technique, and the films are characterized using electrochemical techniques. In addition, the chemically deposited Cu<SUB>x</SUB>S films are investigated as a counter electrode in quantum dots-sensitized solar cells (QSSCs). The available redox active reaction sites of the p-Cu<SUB>x</SUB>S film are found to be 57.9% higher than those available in the c-Cu<SUB>x</SUB>S film. From the electrochemical impedance spectroscopy, the effective diffusion coefficients of the polysulfide electrolyte in the c-Cu<SUB>x</SUB>S and p-Cu<SUB>x</SUB>S films are estimated to be 3.67 x 10<SUP>-5</SUP> and 6.35 x 10<SUP>-5</SUP> cm<SUP>2</SUP> s<SUP>-1</SUP>, respectively. These results can be ascribed to the improvement in the available redox active reaction sites and the electrocatalytic activity of the Cu<SUB>x</SUB>S counter electrode. As compared to the c-Cu<SUB>x</SUB>S film, the p-Cu<SUB>x</SUB>S film as a counter electrode exhibits an enhanced photovoltaic performance of the QSSCs with the power conversion efficiency of 3.17%, short-circuit current of 11.89 mA c<SUP>-</SUP>m<SUP>2</SUP>, open-circuit voltage of 0.50 V, and fill factor of 53.29. The improved performance of the QSSCs is ascribed to the improvements on the available redox active reaction sites, electrocatalytic activity and the diffusion coefficients, which are directly related to the surface morphology of the sulfide films.

Rational Design of Low Cost and High Energy Lithium Batteries through Tailored Fluorine-free Electrolyte and Nanostructured S/C Composite

Agostini, M.,Lim, D.-H.,Sadd, M.,Hwang, J.-Y.,Brutti, S.,Heo, J. W.,Ahn, J. H.,Sun, Y. K.,Matic, A. Wiley (John WileySons) 2018 ChemSusChem Vol.11 No.17

<P>We report a new Li-S cell concept based on an optimized F-free catholyte solution and a high loading nanostructured C/S composite cathode. The Li2S8 present in the electrolyte ensures both buffering against active material dissolution and Li+ conduction. The high S loading is obtained by confining elemental S (approximate to 80%) in the pores of a highly ordered mesopores carbon (CMK3). With this concept we demonstrate stabilization of a high energy density and excellent cycling performance over 500 cycles. This Li-S cell has a specific capacity that reaches over 1000 mA hg(-1), with an overall S loading of 3.6 mg cm(-2) and low electrolyte volume (i.e., 10 mu L cm(-2)), resulting in a practical energy density of 365 Wh kg(-1). The Li-S system proposed thus meets the requirements for large scale energy storage systems and is expected to be environmentally friendly and have lower cost compared with the commercial Li-ion battery thanks to the removal of both Co and F from the overall formulation.</P>

Pivotal role of the RanBP9-cofilin pathway in Aβ-induced apoptosis and neurodegeneration

Woo, J A,Jung, A R,Lakshmana, M K,Bedrossian, A,Lim, Y,Bu, J H,Park, S A,Koo, E H,Mook-Jung, I,Kang, D E Macmillan Publishers Limited 2012 CELL DEATH AND DIFFERENTIATION Vol.19 No.9

Neurodegeneration associated with amyloid β (Aβ) peptide accumulation, synaptic loss, neuroinflammation, tauopathy, and memory impairments encompass the pathophysiological features of Alzheimer's disease (AD). We previously reported that the scaffolding protein RanBP9, which is overall increased in brains of AD patients, simultaneously promotes Aβ generation and focal adhesion disruption by accelerating the endocytosis of amyloid precursor protein (APP) and β1-integrin, respectively. Here, we show that RanBP9 protein levels are increased by fourfold in FAD mutant APP transgenic mice. Accordingly, RanBP9 transgenic mice demonstrate significantly increased synapse loss, neurodegeneration, gliosis, and spatial memory deficits. RanBP9 overexpression promotes apoptosis and potentiates Aβ-induced neurotoxicity independent of its capacity to promote Aβ generation. Conversely, RanBP9 reduction by siRNA or gene dosage mitigates Aβ-induced neurotoxicity. Importantly, RanBP9 activates/dephosphorylates cofilin, a key regulator of actin dynamics and mitochondria-mediated apoptosis, and siRNA knockdown of cofilin abolishes both Aβ and RanBP9-induced apoptosis. These findings implicate the RanBP9–cofilin pathway as critical therapeutic targets not only for stemming Aβ generation but also antagonizing Aβ-induced neurotoxicity.

Self-Organization of Ink-jet-Printed Triisopropylsilylethynyl Pentacene via Evaporation-Induced Flows in a Drying Droplet

Lim, J. A.,Lee, W. H.,Lee, H. S.,Lee, J. H.,Park, Y. D.,Cho, K. WILEY-VCH Verlag 2008 Advanced functional materials Vol.18 No.2

<P>We have demonstrated the influence of evaporation-induced flow in a single droplet on the crystalline microstructure and film morphology of an ink-jet-printed organic semiconductor, 6,13-bis((triisopropylsilylethynyl) pentacene (TIPS_PEN), by varying the composition of the solvent mixture. The ringlike deposits induced by outward convective flow in the droplets have a randomly oriented crystalline structure. The addition of dichlorobenzene as an evaporation control agent results in a homogeneous film morphology due to slow evaporation, but the molecular orientation of the film is undesirable in that it is similar to that of the ring-deposited films. However, self-aligned TIPS_PEN crystals with highly ordered crystalline structures were successfully produced when dodecane was added. Dodecane has a high boiling point and a low surface tension, and its addition to the solvent results in a recirculation flow in the droplets that is induced by a Marangoni flow (surface-tension-driven flow), which arises during the drying processes in the direction opposite to the convective flow. The field-effect transistors fabricated with these self-aligned crystals via ink-jet printing exhibit significantly improved performance with an average effective field-effect mobility of 0.12 cm<SUP>2</SUP> V<SUP>–1</SUP> s<SUP>–1</SUP>. These results demonstrate that with the choice of appropriate solvent ink-jet printing is an excellent method for the production of organic semiconductor films with uniform morphology and desired molecular orientation for the direct-write fabrication of high-performance organic electronics.</P> <B>Graphic Abstract</B> <P>Self-organization of ink-jet printed organic semiconductor with highly ordered crystalline structures can be produced by the evaporation-induced recirculation flow in a drying droplet (see figure). The influence of the evaporation-induced flow in a single droplet on the crystalline microstructure and film morphology of ink-jet-printed triisopropylsilylethynyl pentacene (TIPS_PEN) by varying the composition of the solvent mixture is systematically investigated and discussed. <img src='wiley_img/1616301X-2008-18-2-ADFM200700859-content.gif' alt='wiley_img/1616301X-2008-18-2-ADFM200700859-content'> </P>

Structure-property relationship of D-A type copolymers based on thienylenevinylene for organic electronics

Kim, Y.A.,Jeon, Y.J.,Kang, M.,Jang, S.Y.,Kim, I.B.,Lim, D.H.,Heo, Y.J.,Kim, D.Y. Elsevier Science 2017 Organic electronics Vol.46 No.-

A series of D-A type conjugated polymers based on (E)-1,2-bis(3-dodecyllthiophen-2-yl)ethene (TV) as electron donor unit and with different repeating subunits, PTVBO8, PTVBT8, PTVTBO12, and PTVTBT12 were synthesized for use in organic field effect transistors and bulk heterojunction organic photovoltaics. Upon incorporation of alkoxy substituents in acceptor units, benzooxadiazole (BO) and benzothiadiazole (BT), polymer solubility improved and higher molecular weight polymers were obtained. In addition, all copolymers showed favorable thermal stability (T<SUB>d</SUB> > 300 <SUP>o</SUP>C), and low band gap properties (1.49-1.67 eV). The thiophene-flanked TV-TBX copolymers, PTVTBO12 and PTVTBT12, exhibited higher molecular weight and superior device performance in both OFETs and OPVs compared with the TV-BX copolymers. The electronic energy levels of copolymers were strongly influenced by the nature of acceptor units, while optical band gaps and shape of molecular orientation of polymer chains were affected by the presence or absence of thiophene spacer. Charge carrier mobilities in TV-TBX copolymers were 1 order of magnitude greater than in TV-BX copolymers. OFETs based on a PTVTBT12 with TG/BC configuration displayed the highest hole mobility of 0.48 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP>. The photovoltaic device containing a PTVTBO12:PC<SUB>71</SUB>BM (1:2 w/w) blend system exhibited best performance with a V<SUB>oc</SUB> of 0.56 V, a short-circuit current density (Jsc) of 13.1 mA cm<SUP>-2</SUP>, a fill factor (FF) of 69%, and a power conversion efficiency (PCE) of 5.0%.

여대생 1인가구의 사회적지지, 주거환경, 식습관과 건강 관련 삶의 질의 상관관계 연구

구정연,김근영,김다희,김선미,김수연,김지아,배춘화,임혜윤,최유현,황선영,정덕유,김지연 이화여자대학교 간호과학대학 2017 이화간호학회지 Vol.- No.51

Purpose: The purpose of this study was to investigate the health-related quality of life (HRQOL) among female college students living alone and analyze the relationship among HRQOL, eating habits, residential environments and social support among female college students living alone. Method: Using a descriptive correlation study design, 151 female college students living alone were recruited through convenience sampling. Instruments were the social support tool developed by Park(1985), residential environment tool developed by Kim and Nam(2015), eating habit tool developed by Park et al(2005), modified by Choi(2012) and the HRQOL tool developed by EuroQol Group(1990). The data were analyzed by average, standard deviation, percentage, t-test, ANOVA, and scheffe test, Pearson’s correlation coefficient using the SPSS 22.0 Version program. Results: Participants’ economic level showed statistically significant differences in social support.(F=4.33, p=.009). There was a statically significant relationship among the types of resident and residential environment evaluation score.(F=4.33, p=.009). Also, there were correlations between HRQOL and social support(Pearson’s r=.165, p=.043), residential environment evaluation score.(r=.284, p<.001). There was a correlation between social support and residential environment evaluation score(r=.202, p=.013). Eating habit showed a correlation between emotional support(r=.164, p=.044) and residential environment evaluation score(r=.200, p=.014). However, perceived health status and eating habit were not significantly associated with HRQOL. Conclusion: As a result of this study, the following conclusions were obtained. There were strong relationships among social support, residential environment and HRQOL in female college students living alone. These findings implied the importance of framing university's guideline and overnment’s policy such as financial support, residential counsel and mental health programs to improve HRQOL for female college students living alone. Since the importance of HRQOL has acquired a great importance, it is critical to collect the data of related factors of HRQOL considering only little research on female college students living alone has been done.

여대생의 월경불편감 정도와 식습관에 관한 연구

김선영,김준희,김찬영,박정우,신선미,안선영,이민혜,이정아,임미선,전현정 이화여자대학교 간호과학대학 2010 이화간호학회지 Vol.- No.44

Purpose: This study was done to identify the correlation between the menstrual discomforts and dietary habits of young university women in order to provide the basic needs and make improvements on the quality of life for women. Method: The Menstrual Discomfort Questionnaire (MDQ) and Nutrition Diagnosis for Health were the tools used. The participants were 279 female university students in Seoul. Result: Factors related to MDQ were found to be the VAS scores (r=.361, p=.002), menstrual discomfort according to stress consciousness (F=3.756, p=.025), experiences of taking medicine (F= 4.130 p= .043), the types of residential forms (F=6.197, p=.000), recognition of menstrual period (F=5.466, p=.020), eating breakfast, the frequency of carbohydrates intake (F=5.28, p=.006), the frequency of vegetable intake, seaweed and mushrooms (F=4.98, p=.008). As a result of the study, there is a correlation between menstrual discomforts of female university students and dietary habits. Conclusion: In order to decrease the discomforts of the menstrual cycle that usually includes pain and bloating a well-balanced dietary habit is needed. A balance diet includes grain, vegetables, and mushroom should be taken in normal meals. We should confine the dietary habits that form severe menstrual discomfort in people and give them recommendations for ideal dietary habits that would ideally decrease the pain caused by menstruation. Therefore it is necessary that the education program and nursing mediation should be developed as a program that would aid in decreasing menstrual discomforts. In future studies, a similar study with at a larger scale should be conducted with more recommended specified nutritional assessment.

여대생의 흡연실태와 흡연, 자아존중감, 우울 간의 관계연구 : 서울시내 4년제 대학교 중심으로

강선아,김세은,김지민,이미현,이수연,이예리,이현정,임나래,정민선,최보영,이자형,정덕유,김현경 이화여자대학교 간호과학대학 2009 이화간호학회지 Vol.- No.43

This study was conducted to find out the actual state of smoking among female college students, their knowledge of harmfulness of smoking and their attitude about abstinence from smoking and to analyze their reasons for starting smoking. By doing so, this study aimed to provide the preliminary data for the educational program that prevents smoking and helps smokers to quit cigarettes. Also, this study was conducted to compare the self-esteem and the propensity to depression between female smokers and female non-smokers. Before carrying out the study, the study subjects were investigated about their gender, age, living allowance, residential condition, religion, high school, and whether or not they repeated a year in their high school in order to identify the factors related to smoking. Also, in case of smokers, their smoking amount, their smoking frequency, their first experience of smoking, their attempt of quitting smoking, etc were examined to find out the state of smoking among female college students. Also, as the core aspect of this study, the relationship of self-esteem and depression with smoking was investigated. As a result, the examination of smoking's effects on depression and self-esteem showed that the stud y subjects in the smoker group had a higher level of depression, indicating that smoking is related to the degree of depression (p-value = .017) (smoker group average: 14.75, non-smoker group average: 11.28). In the aspect of self-esteem, it was shown that the more self-esteem the subjects have, the more frequently they smoke, suggesting that whether or not people smoke is not related to the degree of their self-esteem (p-value = .017).

Electrochemical Properties of Gel Copolymer-Electrolyte Based on Phosphonium Ionic Liquid

차은희,S.A. Lim,J.H. Park,김동원,박주훈 한국전기화학회 2008 한국전기화학회지 Vol.11 No.4

Noble Poly (lithium 2-acrylamido-2-methyl propane sulfonate) and its copolymer withN-vinyl formamide based on trihexyl (tetradecyl) phosphonium acetate [(C6H13)3 P (C14H29)CH3COO; P66614 CH3COO) and trihexyl (tetradecyl)phosphonium bis(trifluoromethane sulfonyl) amide([(C6H13)3P(C14H29)] [TFSA];P66614TFSA) were prepared and analyzed to determine their characteristicsand properties. The ionic conductivity of a copolymer based P66614TFSA ionic liquidsystem exhibits a higher conductivity (8.9 × 10-5Scm-1) than that of a copolymer basedP66614CH3COO system (1.57 × 10-5Scm-1). The charge on the TFSA anion is spread very diffuselythrough the S-N-S core and particularly in the trifluoromethane groups, and this diffusionresults in a decreased interaction between the cation and the anion. The viscosity of P66614TFSA(39 cP at 343 K) and P66614CH3COO (124 cP at 343 K), which is very hydrophobic, was fairlyhigh. High viscosity leads to a slow rate of diffusion of redox species. The ionic conductivityof copolymer of a phosphonium ionic liquid system also exhibits higher conductivity than thatof a homopolymer system. Phosphonium ionic liquids were thermally stable at temperatures upto 400oC

Electrochemical properties of gel copolymer- electrolyte based on Phosphonium ionic liquid

Cha, E.H.,Lim, S.A.,Park, J.H.,Kim, D.W.,Park, J.H. The Korean Electrochemical Society 2008 한국전기화학회지 Vol.11 No.4

Noble Poly (lithium 2-acrylamido-2-methyl propane sulfonate) and its copolymer with N-vinyl formamide based on trihexyl (tetradecyl) phosphonium acetate [$(C_6H_{13})_3$ P ($C_{14}H_{29}$) $CH_3COO$; $P_{66614}$ $CH_3COO$] and trihexyl (tetradecyl)phosphonium bis(trifluoromethane sulfonyl) amide ([$(C_6H_{13})_3P(C_{14}H_{29})$] [TFSA];$P_{66614}TFSA$) were prepared and analyzed to determine their characteristics and properties. The ionic conductivity of a copolymer based $P_{66614}TFSA$ ionic liquid system exhibits a higher conductivity ($8.9{\times}10^{-5}Scm^{-1}$) than that of a copolymer based $P_{66614}CH_3COO$ system ($1.57{\times}10^{-5}Scm^{-1})$. The charge on the TFSA anion is spread very diffusely through the S-N-S core and particularly in the trifluoromethane groups, and this diffusion results in a decreased interaction between the cation and the anion. The viscosity of $P_{66614}TFSA$ (39 cP at 343 K) and $P_{66614}CH_3COO$ (124 cP at 343 K), which is very hydrophobic, was fairly high. High viscosity leads to a slow rate of diffusion of redox species. The ionic conductivity of copolymer of a phosphonium ionic liquid system also exhibits higher conductivity than that of a homopolymer system. Phosphonium ionic liquids were thermally stable at temperatures up to $400^{\circ}C$.