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Dual signaling of water contents of biofuel-relevant ethanol and butanol by pyranines
Jung, Y.u.,Choi, M.G.,Lee, S.H.,Chang, S.K. Elsevier Sequoia 2017 Sensors and actuators. B Chemical Vol.241 No.-
<P>Novel optical sensors for measuring the water contents of biofuel-relevant ethanol and 1-butanol based on the pyranine fluorophore were investigated. The diethylsulfonamide derivative of pyranine showed a pronounced absorption and fluorescent signaling in response to changes in the water content of ethanol and 1-butanol. This signaling was based on the increased dissociation of the acidic hydroxy group of pyranine in response to the increasing water content of the alcohol solutions. The signaling behavior of the sensors was readily analyzed by ratiometric measurements using the absorption and fluorescence characteristics of the undissociated and dissociated forms. Upon the derivatization to diethylsulfonamide, the signaling became more sensitive than that for its parent pyranine. The detection limits of the pyranine and diethylsulfonamide derivative for the measurement of the water content in ethanol were 1.9% and 0.03%, respectively. On the other hand, the detection limit of the diethylsulfonamide derivative for the determination of the water content in 1-butanol was 0.01%, whereas underivatized pyranine was not useful because of the limited solubility of the sensor. The practical application of this method for measuring the water content in ethanol and 1-butanol using a smartphone as an easy-to-use signal capturing device was also explored. (C) 2016 Elsevier B.V. All rights reserved.</P>
Concomitant occurrence of Turner syndrome and growth hormone deficiency
Jung Yu,Ha Young Shin,Chong Guk Lee,Jae Hyun Kim 대한소아청소년과학회 2016 Clinical and Experimental Pediatrics (CEP) Vol.59 No.no.sup1
Turner syndrome (TS) is a genetic disorder in phenotypic females that has characteristic physical features and presents as partial or complete absence of the second sex chromosome. Growth hormone deficiency (GHD) is a condition caused by insufficient release of growth hormone from the pituitary gland. The concomitant occurrence of TS and GHD is rare and has not yet been reported in Korea. Here we report 2 cases of TS and GHD. In case 1, GHD was initially diagnosed. Karyotyping was performed because of the presence of the typical phenotype and poor response to growth hormone therapy, which revealed 45,X/45,X+mar. The patient showed increased growth velocity after the growth hormone dose was increased. In case 2, a growth hormone provocation test and chromosomal analysis were performed simultaneously because of decreased growth velocity and the typical TS phenotype, which showed GHD and a mosaic karyotype of 45,X/46,XX. The patient showed spontaneous pubertal development. In female patients with short stature, it is important to perform a throughout physical examination and test for hormonal and chromosomal abnormalities because diagnostic accuracy is important for treatment and prognosis.
Electromechanical properties of graphene transparent conducting films for flexible electronics
Jung, Y.U.,Oh, S.i.,Choa, S.H.,Kim, H.K.,Kang, S.J. Elsevier 2013 CURRENT APPLIED PHYSICS Vol.13 No.7
We report a systematic study of the electromechanical properties of graphene films for flexible transparent conducting electrodes. The flexibility of graphene films, which were grown using a chemical vapor deposition (CVD) method and transfer process on polyethylene terephthalate (PET) substrates, was investigated using a lab-made inner/outer bending, twisting and stretching test system. The electromechanical properties as a function of the change of bending radius, twisting angle and strain distance were evaluated by measuring the change in resistance. The change in resistance during the inner bending test was less than 8% even when the bending radius was 3 mm. Additionally, the results of the inner bending fatigue test showed a constant resistance throughout 2000 bending cycles. However, in the outer bending test, the resistance increased substantially when the bending radius was smaller than 10 mm. Therefore, we can expect that more cracks form between the grains of graphene during the outer bending test. The twistability and stretchability of the graphene film were also investigated. Both twisting and stretching tests show gradually increasing resistances according to the twisting angle and stretching distance. These results provide useful information regarding the electromechanical properties of graphene transparent conducting films for the development of flexible electronics.
Clustering Algorithm for Time Series with Similar Shapes
( Jungyu Ahn ),( Ju-hong Lee ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7
Since time series clustering is performed without prior information, it is used for exploratory data analysis. In particular, clusters of time series with similar shapes can be used in various fields, such as business, medicine, finance, and communications. However, existing time series clustering algorithms have a problem in that time series with different shapes are included in the clusters. The reason for such a problem is that the existing algorithms do not consider the limitations on the size of the generated clusters, and use a dimension reduction method in which the information loss is large. In this paper, we propose a method to alleviate the disadvantages of existing methods and to find a better quality of cluster containing similarly shaped time series. In the data preprocessing step, we normalize the time series using z-transformation. Then, we use piecewise aggregate approximation (PAA) to reduce the dimension of the time series. In the clustering step, we use density-based spatial clustering of applications with noise (DBSCAN) to create a precluster. We then use a modified K-means algorithm to refine the preclusters containing differently shaped time series into subclusters containing only similarly shaped time series. In our experiments, our method showed better results than the existing method.
돈사의 공기역학적 문제점에 대한 교육용 CFD-VR 시뮬레이터 개발
김준규 ( Jungyu Kim ),김락우 ( Rackwoo Kim ),이인복 ( In-bok Lee ) 한국농공학회 2017 한국농공학회 학술대회초록집 Vol.2017 No.-
최근 우리나라 축산업의 발전에 따라 농업생산액의 43%에 달하며, 이중에서도 양돈의 생산량 및 소비량은 축산업에서 가장 많은 비중을 차지하고 있다. 이와 더불어 양돈시설의 현대화, 대형화가 이루어지면서, 시설 내부 환경의 균일성 및 안정성 유지에 문제점이 다수 발생하고 있다. 온도, 가스, 습도, 분진 등의 환경 조절은 내부 환경 요소의 열전달 및 물질전달의 주 메커니즘인 공기 유동의 영향을 받으며, 이는 눈에 보이지 않아 예측 및 측정이 어렵기 때문에 축산업 종사자들 중 약 75%가 환기, 내부 유동 등을 잘못 이해하고 있는 실정이다. 특히, 사계절이 뚜렷하여 혹서기, 혹한기와 같이 극심한 환경에서 돈사 관리에 많은 문제점들이 발생하기 때문에, 다수의 양돈 농가에서 내부 환경 조절에 많은 어려움을 겪고 있다. 한편 보이지 않는 기류에 대한 공기역학적인 분석을 실시하여도 이를 실제 농가들이 쉽게 이해하기 위해서는 공기 유동을 가시화하는 기술이 필요하다. 최근 4차 산업 혁명과 함께 사용자가 다양한 현상들을 직접 체험할 수 있는 가상현실 기술이 부상하고 있으나 현재까지 농업 시설, 특히 온실에 적용한 사례는 전무한 현실이다.이에 본 연구에서는 CFD를 이용한 양돈 농가에서 발생하는 주요 문제점들을 공기역학적 분석을 수행하고, 이를 바탕으로 가상현실 기술을 통해 내부 공기 유동을 가시화 하여 농민 교육용 가상현실 시뮬레이터를 개발하고자 하였다. 대상시설은 2009년도 대한양돈협회 표준돈사설계도의 이유자돈방으로 선정하였으며, 농민 및 농업 컨설턴트들을 위한 가상현실 시뮬레이터 제작을 위하여, 우선적으로 실제 국내 돈사에서 발생하고 있는 다양한 문제점들에 대한 현장조사 및 문헌조사를 실시하였다. 이를 바탕으로 문제점과 개선사항의 연산케이스를 선정하여 CFD 모델을 설계 및 수치해석을 수행하였다. 연산된 CFD 결과들이 가상현실로 구현될 수 있도록 가상현실 프로그램을 설계하고, 사용자들에게 쉽게 접근할 수 있는 가상현실 User Interface를 구축하였다. 가상현실 모델을 실제와 같이 설계하기 위하여 돈사와 돼지의 다각도 촬영 자료를 바탕으로 이미지 텍스처를 제작하고, 이용자의 어지러움증 유발을 방지하기 위하여 수차례 거쳐 최적화 작업을 진행하였다. 최종적으로 가상현실 시뮬레이터를 통해 CFD 해석 결과를 가시화하여 농민들이 공기역학적인 현상을 체험할 수 있는 양돈농가 교육용 시뮬레이터를 완성하였다.