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산업단지 및 일반생활 지역의 공기 중 톨루엔에 대한 개인노출 및 생체시료의 상관성 분석
이병준(Byoungjun Lee),허 정(Jung Heo),정다영(Dayoung Jung),김순신(Sunshin Kim),류현수(Hyeon-Su Ryu),최민지(Min-Ji Choi),솨이지엔페이(Jian-Fei Shuai),임성국(Sung-Guk Im),양원호(Wonho Yang) 한국환경보건학회 2017 한국환경보건학회지 Vol.43 No.4
Objectives: The purpose of this study was to assess the correlation relationship between personal exposure and urinary hippuric acid in biological monitoring for airborne toluene in an industrial complex and in general environments. Methods: Personal exposure to toluene and its metabolite, hippuric acid, in urine were simultaneously measured in occupational environments area near an industrial complex and in general environments. The study subjects were divided into three types: 137 workers who use organic solvents in the workplace, 210 residents living near a dyeing industrial complex, and 379 residents living in general environments. The toluene exposures of workers and residents were measured by a passive sampler for four days. The urine of participants was sampled when the passive samplers of personal exposure were collected. Results: The toluene and hippuric acid concentrations of workers were the highest, followed by the concentrations of residents living near a dyeing industrial complex and residents living in general environments. The coefficient of correlation between the concentrations of toluene and hippuric acid among workers was 0.749 (p<0.01) in the workplace. On the contrary, correlations between the concentrations of toluene and hippuric acid among residents living near a dyeing industrial complex and residents living in general environments were all not significant. The relationship between the concentrations of hippuric acid and toluene in three types could be described by the exponential growth model. Conclusions: This study analyzed the relationships between toluene exposure and the concentrations of hippuric acid in urine in high, middle, and low exposure environments, and could be described by the exponential growth model.
Choi, Dukhyun,Choi, Min-Yeol,Choi, Won Mook,Shin, Hyeon-Jin,Park, Hyun-Kyu,Seo, Ju-Seok,Park, Jongbong,Yoon, Seon-Mi,Chae, Seung Jin,Lee, Young Hee,Kim, Sang-Woo,Choi, Jae-Young,Lee, Sang Yoon,Kim, Jo WILEY-VCH Verlag 2010 ADVANCED MATERIALS Vol.22 No.19
<B>Graphic Abstract</B> <P>The cover shows an image of fully rollable transparent nanogenerators synthesized using chemical vapor deposition grown large-scale graphene sheets as transparent electrodes and piezoelectric ZnO nanorod arrays. Sang-Woo Kim, Jae-Young Choi, and co-workers report on p. 2187 the electrical and structural stability of the nanogenerators, with excellent charge scavenging performance under external mechanical loads such as bending and rolling. This study shows that graphene-based nanogenerators are very promising for self-powered rollable transparent device applications. <img src='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content.gif' alt='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content'> </P>
( Sung Bae Cho ),( Jongmin Lee ),( Hyeon Hui Kang ),( Hwa Sik Moon ),( Sang Haak Lee ) 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1
Background: Recent researches suggest that chronic obstructive pulmonary disease (COPD) is associated with an increased risk of peptic ulcer disease, but limited data exist on affecting factors in COPD patient with peptic ulcer disease on gastroduodenoscopy. Methods: We retrospectively reviewed medical records on 237 COPD patients who performed gastroduodenoscopy in 2003-2013. Patients were divided into two groups accordingly: peptic ulcer (gastric and/or duodenal ulcer) group and non-ulcerative disease group. Statistical analyses were performed with the logistic regression model to obtain the factors affecting peptic ulceration in COPD patients, controlling confounding factors. Results: The prevalence of peptic ulcer disease was 99 of 237 COPD patients (41.7%) and a male sex had a positive association with peptic ulcer disease (odds ratio[OR], 2.270, 95% confidence interval[CI], 1.189 to 4.332). There was independent relationships between the presence of peptic ulcer disease and both liters of predicted forced expiratory volume in 1s (FEV1) (OR, 0.407, 95% CI, 0.229 to 0.724) and liters of functional vital capacity (FVC) (OR, 1.029, 95% CI, 1.011 to 1.048). Smoking status and corticosteroids, known risk factors of peptic ulcer disease in general population, did not showed expected affect on peptic ulceration. Conclusions: Our findings provide further evidence that COPD is associated with peptic ulcer disease and there is an increased risk for peptic ulcer associated with COPD severity.
Lee, Ju Hyeon,Seo, Jung Uk,Chung, Yun Joong,Lee, Jae Chun,Park, Sung Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.317 No.-
<P>ZnO nanopowder was prepared by a novel “solution-combustion method (SCM)” and it was used as a semiconductor photocatalyst to evaluate its photoreduction properties. Aqueous Pb-EDTA and Cu-EDTA solutions of heavy metal ions (Pb and Cu) were used for the photocatalysis reaction under UV illumination. The result was then compared with other semiconductor photocatalyst powder such as TiO2 powder (P25; Degussa) and TiO2 powder prepared by homogeneous precipitation process at low temperature (HPPLT). In the removal of Pb++ ions, the ZnO nanopowder showed 2.6 fold higher removal rate than P25 TiO2 powder and 1.8 fold higher than HPPLT TiO2. Also the ZnO nanopowder showed the highest removal rate of the Cu++ ions from the solution among the different photocatalyst powders compared. The superior photoreduction ability of the ZnO nanopowder appears to be due to its excellent UV absorption characteristics. This was confirmed by the photoluminescence (PL) measurement.</P>
Lee, Yong Kyu,Ahn, Kyunghan,Cha, Joonil,Zhou, Chongjian,Kim, Hyo Seok,Choi, Garam,Chae, Sue In,Park, Jae-Hyuk,Cho, Sung-Pyo,Park, Sang Hyun,Sung, Yung-Eun,Lee, Won Bo,Hyeon, Taeghwan,Chung, In American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.31
<P>SnSe emerges as a new class of thermoelectric materials since the recent discovery of an ultrahigh thermoelectric figure of merit in its single crystals. Achieving such performance in the polycrystalline counterpart is still challenging and requires fundamental understandings of its electrical and thermal transport properties as well as structural chemistry. Here we demonstrate a new strategy of improving conversion efficiency of bulk polycrystalline SnSe thermoelethics. We show that PbSe alloying decreases the transition temperature between Pnma and Cmcm phases and thereby can serve as a means of controlling its onset temperature. Along with 1% Na doping, delicate control of the alloying fraction markedly enhances electrical conductivity by earlier initiation of bipolar conduction while reducing lattice thermal conductivity by alloy and point defect scattering simultaneously. As a result, a remarkably high peak ZT of similar to 1.2 at 773 K as well as average ZT of similar to 0.5 from RT to 773 K is achieved for Na-0.01(Sn1-xPbx)(0.99)Se. Surprisingly, spherical-aberration corrected scanning transmission electron microscopic studies reveal that NaySn1-xPbxSe (0 < x <= 0.2; y = 0, 0.01) alloys spontaneously form nanoscale particles with a typical size of similar to 5-10 nm embedded inside the bulk matrix, rather than solid solutions as previously believed. This unexpected feature results in further reduction in their lattice thermal conductivity.</P>
Optical design of ZnO-based antireflective layers for enhanced GaAs solar cell performance
Lee, Hye Jin,Lee, Jae Won,Kim, Hee Jun,Jung, Dae-Han,Lee, Ki-Suk,Kim, Sang Hyeon,Geum, Dae-myeong,Kim, Chang Zoo,Choi, Won Jun,Baik, Jeong Min The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.4
<P>A series of hierarchical ZnO-based antireflection coatings with different nanostructures (nanowires and nanosheets) is prepared hydrothermally, followed by means of RF sputtering of MgF2 layers for coaxial nanostructures. Structural analysis showed that both ZnO had a highly preferred orientation along the < 0001 > direction with a highly crystalline MgF2 shell coated uniformly. However, a small amount of Al was present in nanosheets, originating from Al diffusion from the Al seed layer, resulting in an increase of the optical bandgap. Compared with the nanosheet-based antireflection coatings, the nanowire-based ones exhibited a significantly lower reflectance (similar to 2%) in ultraviolet and visible light wavelength regions. In particular, they showed perfect light absorption at wavelength less than approximately 400 nm. However, a GaAs single junction solar cell with nanosheet-based antireflection coatings showed the largest enhancement (43.9%) in power conversion efficiency. These results show that the increase of the optical bandgap of the nanosheets by the incorporation of Al atoms allows more photons enter the active region of the solar cell, improving the performance.</P>