• Asia pacific journal of information systems
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• 제33권3호
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• pp.541-572
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• 2023

Amazon Go is a cashierless convenience store concept, which is seen as a disruption in the grocery retail segment. Although Amazon Go has the ability to disrupt the retail segment, there are speculations on how Amazon Go will be perceived by users. Existing studies have not utilized user-generated content to understand the factors that affect customer behaviour in case of Amazon Go. Additionally, in case of phygital retail, studies have not attempted at understanding the effect of emotions and gratifications on user behaviour. To address the gap of exploring user perspectives based on their experience, we have examined the impact of gratifications and emotions on the acceptance of phygital retail using user-generated-content. A mixed-method approach has been utilized using only user-generated content. Utilizing topic-modelling based content analysis and emotion analysis on 30 articles related to Amazon Go, we found themes like, convenience, technology, experience, personalization, enjoyment and emotions like, bad, good, annoyance, success. In the empirical analysis, we have utilized 522 reviews about Amazon Go from the cognition and emotion theory stance, and found that hedonic gratifications have a positive impact on challenge emotions. We also found a significant impact of emotions on customer's favourite behaviour.

• 동의생리병리학회지
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• 제16권1호
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• pp.141-145
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• 2002

In order to clarify the neuroprotective effect of Gamibojungikki-tang (GBJIKT) water extract on cultured mouse spinal sensory neuron damaged by glucose Oxidase (GO), MTT [3-(4,5-dimethylthiazole-2-yl) -2,5-diphenyltetrazolium bromide] assay and SRB (Sulforhodamine B) assay were carried out after the cultured mouse spinal sensory neuron were preincubated with various concentrations of GBJIKT water extract for 3 hours prior to exposure of GO. Cell viability of cultured mouse spinal sensory neurons exposed to various concentrations of GO for 8 hours was decreased in a dose-dependent manner. MTT50 values were 45 mU/ml GO. Cultured mouse spinal sensory neurons in the medium containing various concentration of GO for 8 hours showed decreasing of total protein synthesis. GO was toxic on cultured spinal sensory neurons. Pretreatment at GBJIKT water extract for 3 hours following GO prevented the GO-induced neurotoxicity such as decreasing of total protein synthesis. These results suggest that GO shows toxic effect on cultured spinal sensory neurons and GBJIKT water extract is highly effective in proecting the neurotoxicity induced by GO.

• 방송공학회논문지
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• 제22권6호
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• pp.724-733
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• 2017

바둑 기보를 자동으로 기록하는 기존의 방법들은 대국 중 발생하는 방해물(손 혹은 물체)의 바둑판 가림 현상을 제대로 고려하지 않았다. 방해물에 의해 바둑판이 가려지는 경우 바둑돌의 착수 위치를 인식하지 못하거나, 바둑돌의 착수 순서가 실제와 다르게 저장되는 문제가 발생할 수 있다. 제안된 알고리즘은 방해물이 없는 온전한 바둑판 영상만을 배경 영상으로 내부에 저장하고 배경 영상과 현재 입력 영상을 비교하여 방해물을 인식한다. 그림자가 방해물로 오인식되는 현상을 제거하기 위해 단순한 차 영상이 아닌 미분영상을 기반으로 한 방해물 검출 방법이 제안되었다. 추가로 노이즈에 강인하게 방해물을 인식하기 위한 노이즈 제거 방법도 제안되었다. 방해물이 없는 때는 배경 영상을 지속적으로 갱신한다. 최종적으로 각 순간마다 저장된 배경 영상들을 비교하여 바둑돌의 착수 위치와 바둑돌의 종류를 인식한다. 실험 결과에 따르면 일반적인 조명환경에서 제안된 알고리즘은 95%이상의 인식률을 보여준다.

• 동의생리병리학회지
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• 제16권2호
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• pp.343-347
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• 2002

In order to darify the neuroprotective effect of Gamibojungikki-tang(GBJIKT) water extract on cultured mouse spinal sensory neuron damaged by glucose Oxidase (GO), NR (Neutral Red) assay and LDH (Lactate Dehydrogenase) activity assay were carried out after the cultured mouse spinal sensory neuron were preincubated with various concentrations of GBJIKT water extract for 3 hours prior to exposure of GO. Cell viability of cultured mouse spinal sensory neurons exposed to various concentrations of GO for 8 hours was decreased in a dose-dependent manner. NR/sub 50/ values were 50 mU/ml GO. Cultured mouse spinal sensory neurons in the medium containing various concentration of GO for 8 hours showed increasing of LDH activity. We knew that GO was toxic on cultured spinal sensory neurons. Pretreatment of GBJIKT water extract for 3 hours following GO prevented the GO-induced neurotoxicity such as increasing of LDH activity. These results suggest that GO shows toxic effect on cultured spinal sensory neurons and GBJIKT water extract is highly effective in proecting the neurotoxicity induced by GO.

• 멤브레인
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• 제23권3호
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• pp.204-210
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• 2013

본 연구는 microfiltration (MF) 적용을 위한 PVdF/GO 하이브리드 나노섬유막(FG) 제조에 관한 것이다. 지지체인 PVdF (polyvinylidene difluoride) 나노섬유막은 N,N-Dimethylacetamide (DMAc)와 아세톤에 PVdF를 녹여 방사용액 제조 후 전기방사법을 이용하여 제조하였다. 본 연구에서 사용된 GO (grapheme oxide) sheets는 Hummer's 방법에 따라 제조되었으며, PVdF 나노섬유 지지체 위에 에탄올에 분산시킨 GO용액을 분사함으로써, 최종적으로 PVdF/GO 하이브리드 나노섬유막(FG)을 제조하였다. FG막은 SEM, Raman, 접촉각, 기공특성분석장치(Porometer), 만능인장시험기(UTM)를 사용하여 조사하였고, 수투과도 분석은 제작된 셀(Dead-End Cell)을 이용하여 측정하였다. 접촉각 측정 결과로부터 제조된 FG막의 표면이 친수성으로 개질되었음을 확인할 수 있었으며, 수투과도값은 PVdF막에 비해 약 2.5배 향상된 것을 확인할 수 있었다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제20권2호
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• pp.61-67
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• 2009

Objectives: The purpose of this study was to examine the performance and electrophysiological characteristics of drug-naive children with attention-deficit/hyperactivity disorder(ADHD) during the Go/NoGo task. Methods: Twenty-three boys with ADHD and 18 age-matched normal boys were recruited at a child psychiatric outpatient clinic in Seoul. All subjects were assessed by the Kiddie Schedules for Affective Disorders and Schizophrenia Present and Lifetime version. The investigator also assessed all subjects using the ADHD Rating Scale-IV(ADHDRS). Event-related potentials were recorded from 8 scalp electrodes during the visual Go/NoGo task. Results: Children with ADHD showed a larger mean of standard deviation of response time during the Go/NoGo task than normal children. The temporal N200 and P300 amplitudes were larger in children with ADHD relative to controls. The parietal N200 and P300 latencies were more prolonged in children with ADHD compared to normal controls. Conclusion: These results suggest that psychotropic-naive children with ADHD may have more variable performance ability, more difficulty in discriminating visual stimuli, and slower information processing speed than their normal age-matched counterparts.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.562-562
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• 2012

Recently, graphene and graphene-based materials such as graphene oxide (GO) or reduced graphene oxide (R-GO) draws a great attention for electronic devices due to their structures of one atomic layer of carbon hexagon that have excellent mechanical, electrical, thermal, optical properties and very high specific surface area that can be high potential for chemical functionalization. R-GO is a promising candidate because it can be prepared with low-cost from solution process by chemical oxidation and exfoliation using strong acids and oxidants to produce graphene oxide (GO) and its subsequent reduction. R-GO has been used as semiconductor or conductor materials as well as sensing layer for bio-molecules or ions. In this work, reduced graphene oxide field-effect transistor (R-GO FET) has been fabricated with ITO extended gate structure that has sensing area on ITO extended gate part. R-GO FET device was encapsulated by tetratetracontane (TTC) layer using thermal evaporation. A thermal annealing process was carried out at $140^{\circ}C$ for 4 hours in the same thermal vacuum chamber to remove defects in R-GO film before deposition of TTC at $50^{\circ}C$ with thickness of 200 nm. As a result of this process, R-GO FET device has a very high stability and durability for months to serve as a transducer for sensing applications.

• 한국분말재료학회지
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• 제23권4호
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• pp.263-269
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• 2016

Graphene oxide (GO) powder processed by Hummer's method is mixed with p-type $Bi_2Te_3$ based thermoelectric materials by a high-energy ball milling process. The synthesized GO-dispersed p-type $Bi_2Te_3$ composite powder has a composition of $Bi_{0.5}Sb_{1.5}Te_3$ (BSbT), and the powder is consolidated into composites with different contents of GO powder by using the spark plasma sintering (SPS) process. It is found that the addition of GO powder significantly decreases the thermal conductivity of the pure BSbT material through active phonon scattering at the newly formed interfaces. In addition, the electrical properties of the GO/BSbT composites are degraded by the addition of GO powder except in the case of the 0.1 wt% GO/BSbT composite. It is found that defects on the surface of GO powder hinder the electrical transport properties. As a result, the maximum thermoelectric performance (ZT value of 0.91) is achieved from the 0.1% GO/BSbT composite at 398 K. These results indicate that introducing GO powder into thermoelectric materials is a promising method to achieve enhanced thermoelectric performance due to the reduction in thermal conductivity.

• 폴리머
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• 제37권2호
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• pp.218-224
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• 2013

Hummers and Offeman 방법을 이용하여 흑연으로부터 산화 그래핀(graphene oxide; GO)을 합성하였고, 이를 이용하여 두 가지 다른 작용기화 그래핀(FGS)을 합성하였다. 그래핀 판상(graphene sheet; GS)에 수직방향으로 hexadecylamine(HDA)이 치환된 Ver-HDA-GS을 HDA와 에폭시기를 반응하여 얻었고, 한편으로, 환원된 GO(Reduced-GO; RGO)를 통하여 hexadecanol(HDO)와 알코올을 반응시켜 HDO가 수평 방향으로 치환된 Hor-HDO-GS를 합성하였다. 합성된 GO, RGO, Ver-HDA-GS 그리고 Hor-HDO-GS의 합성여부를 확인하기 위하여 FTIR을 이용하였으며, 합성된 물질들의 열 안정성 및 모폴로지를 각각 확인하였다. 원자간력 현미경(AFM)을 통해서 Ver-HDA-GS는 한 층 또는 두 층 두께의 그래핀으로 이루어졌고, 평균 두께는 1.76 nm임을 확인하였다. 합성된 FGS들의 열 안정성은 GO나 RGO보다 더 나았으며, 분산도의 경우에 Ver-HDA-GS는 DMSO, 톨루엔, 클로로포름, 데카린 등의 일상적인 용매에서 잘 분산되었다.

• 한국건축시공학회지
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• 제23권4호
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• pp.381-392
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• 2023

본 연구에서는 산화 그래핀 나노플레이트릿(Oxidized graphene nanoplatelet, GO)와 유공유리분말(Hollow glass powder, HGP)를 활용한 초고강도 콘크리트의 역학특성을 검토하였으며 이를 위해 작업성, 강도(압축, 인장), 수밀성, 내부조직을 검토하였다. 그 결과 HGP 소량 투입으로 작업성능을 획기적으로 회복시킬 수 있었고 강도특성 및 수밀성도 증가하는 것으로 나타났다. cGO(C사의 GO) 와 HGP는 응집현상 없이 분산이 잘 되어 있는 것으로 확인되었고 공극량은 20% 이상 감소하는 것으로 나타났다. cGO와 HGP가 실리카 흄(Silica fume, SF)을 대체할 수 있는지에 대해서도 검토하였다. cGO와 HGP의 사용으로 SF 없이도 쉽게 작업성을 확보할 수 있었고 역학특성도 향상되는 것으로 나타났으며 신재료의 사용으로 콘크리트 제조방법의 변화가 가능함을 확인할 수 있었다.