Silver nanowire-embedded PDMS with a multiscale structure for a highly sensitive and robust flexible pressure sensor

Joo, Yunsik,Byun, Junghwan,Seong, Narkhyeon,Ha, Jewook,Kim, Hyunjong,Kim, Sangwoo,Kim, Taehoon,Im, Hwarim,Kim, Donghyun,Hong, Yongtaek The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.14

<P>The development of highly sensitive pressure sensors with a low-cost and facile fabrication technique is desirable for electronic skins and wearable sensing devices. Here a low-cost and facile fabrication strategy to obtain multiscale-structured elastomeric electrodes and a highly sensitive and robust flexible pressure sensor is presented. The principles of spontaneous buckle formation of the PDMS surface and the embedding of silver nanowires are used to fabricate the multiscale-structured elastomeric electrode. By laminating the multiscale-structured elastomeric electrode onto the dielectric layer/bottom electrode template, the pressure sensor can be obtained. The pressure sensor is based on the capacitive sensing mechanism and shows high sensitivity (>3.8 kPa<SUP>−1</SUP>), fast response and relaxation time (<150 ms), high bending stability and high cycle stability. The fabrication process can be easily scaled up to produce pressure sensor arrays and they can detect the spatial distribution of the applied pressure. It is also demonstrated that the fingertip pressure sensing device can sense the pressure distribution of each finger, when grabbing an object.</P>

Evaluation of thermal efficiency by in-situ thermal response test on large diameter cast-in-place energy piles

Sangwoo Park(박상우),Hyunjun Choi(최현준),Kyoung-Sik Jung(정경식),Byong-Hu Sohn(손병후),Yongsun Joo(주용선),Hangseok Choi(최항석) 한국신재생에너지학회 2013 한국신재생에너지학회 학술대회논문집 Vol.2013 No.05

PRELIMINARY DESIGN METHOD FOR CAST-IN-PLACE ENERGY PILE

Sangwoo Park,Culho Lee,Kyoung-Sik Jung,Yongsun Joo,Hangseok Choi 한국신재생에너지학회 2012 AFORE Vol.2012 No.-

Amelioration of Cerebral Ischemic Injury by a Synthetic Seco-nucleoside LMT497

Ryu, Sangwoo,Kwon, Joonha,Park, Hyeon,Choi, In-Young,Hwang, Sunyoung,Gajulapati, Veeraswamy,Lee, Joo Young,Choi, Yongseok,Varani, Katia,Borea, Pier Andrea,Ju, Chung,Kim, Won-Ki The Korean Society for Brain and Neural Science 2015 Experimental Neurobiology Vol.24 No.1

<P>Recently, we reported that the A3 adenosine receptor (A<SUB>3</SUB>AR) agonist LJ529 (2-chloro-N<SUP>6</SUP>-(3-iodobnzyl)-5'-N-methylcarbamoyl-4'-thioadenosine) reduces cerebral ischemic injury via inhibition of recruitment of peripheral inflammatory cells into ischemic brain lesion. A3AR agonists, however, are known to possess anti-platelet activity, which may deter the combination therapy with tissue plasminogen activator for the therapy of cerebral ischemic stroke. Thus, the present study investigates the neuroprotective/anti-ischemic effect of a synthetic seco-nucleoside, LMT497 ((<I>S</I>)-2-((<I>R</I>)-1-(2-chloro-6-(3-iodobenzylamino)-9<I>H</I>-purin-9-yl)-2-hydroxyethoxy)-3-hydroxy-<I>N</I>-methylpropanamide) with little anti-platelet activity. LMT497 neither showed A<SUB>3</SUB>AR binding activity nor anti-platelet activity. In our present study LMT497 significantly attenuated the injury/death of cortical neurons exposed to oxygen-glucose deprivation (OGD) followed by re-oxygenation (R). LMT497 significantly reduced the ascending cellular level of reactive oxygen species under ischemic conditions by increasing the superoxide dismutase (SOD) levels. LMT497 also inhibited the migration of microglia which mediates inflammatory responses in ischemia. In rats subjected to middle cerebral artery occlusion (MCAO, 1.5 h) followed by reperfusion, LMT497 largely reduced brain infarction volume, and edema, and improved neurological score. Therapeutic efficacy of LMT497 was obtained by twice treatments even at 10 h and 18 h after the onset of ischemia. Collectively, LMT497 could be a therapeutic drug candidate with a wide therapeutic time window for the treatment of cerebral ischemic stroke.</P>

구조해석을 통한 T/CON 피스톤 처짐량 및 피로수명에 대한 연구

임상우(Sangwoo Lim),이웅철(Woongchul Lee),권의섭(Eaisub Kwon),신순철(Sooncheol Shin),주인식(Insik Joo) 한국자동차공학회 2013 한국자동차공학회 학술대회 및 전시회 Vol.2013 No.11

Torque converter consists of fluid clutch and lock-up clutch. When the lock-up clutch activates, piston operation transfers the engine power to the transmission. In recent times, in order to meet the requirements for light weight and stability, Torque converter requires optimized design using structural analysis considering maximum load. The most effective parts to lightweight is piston of lock-up clutch which is necessary design criteria. In addition, study for life optimization was conducted. For analysis, piston shape is of single facing clutch type. In the future, this study will aid for structural design of piston.

휴대전화 슬라이드 조작감의 주관적 감성 모형에 관한 연구

반상우(Sangwoo Bahn),권오채(Oche Kwon),송주봉(Joo Bong Song),권상현(Sanghyun Kwon),윤명환(Myung Hwan Yun) 한국HCI학회 2010 한국HCI학회 학술대회 Vol.2010 No.1

휴대전화를 열고 닫는 동작을 하면서 촉각 및 체감각을 통해 인지되는 감각은 휴대전화에 대한 감성적 반응에 많은 영향을 미치지만, 제품의 사용작업 중에 발생하는 조작감에 대한 연구는 많이 이루어지고 있지 않으며, 제품 디자인 프로세스는 대부분 기능성 확보나 외형적 심미성을 충족하는 데 중점을 두고 있다. 본 연구에서는 슬라이드형 휴대전화를 대상으로 슬라이드를 열고 닫는 동작에서 사람들이 느끼는 조작감에 대한 감성을 구체적인 감성 요소 변수를 이용하여 평가하고 통계적인 방법론을 활용하여 모델링 하였다. 이를 위하여 총 25 종의 휴대전화를 대상으로 40 명(남:20, 여:20)의 피실험자에 대하여 평가 실험을 실시하였으며, 평가 실험 결과는 분산 분석, 컨조인트 분석, 다차원 척도법 등을 사용하여 통계적으로 분석하였다. 분석 결과 마찰력, 구동부 속도, 두께가 슬라이드 조작 감성에 주로 영향을 미치는 주요 변수로 파악되었으며, 조작 감성을 향상시키기 위한 설계 변수의 조합이 도출되었다. 본 연구를 통하여 슬라이드형 제품의 조작감을 정의하고, 이에 영향을 미치는 각 요소와 조작감성을 향상시킬 수 있는 방안을 파악할 수 있었다. We have a feel for sliding control of mobile phone's upper cover through kinesthetic and tactile senses, and this feeling has an effect of affective evaluation for the mobile phone. But there are very few studies about control feels of products or mobile phones and design process mainly focuses on ensuring functional needs or aesthetic aspects of physical appearance. The purpose of this study is defining the control feel of slide type mobile phone using affective variable and engineering variables. A total of 25 various slide type mobile phone and 40 participants (male: 20, female: 20) were employed to evaluate the mobile phone samples using the questionnaire based on affective variables. Utilizing some multivariate statistical analysis such as ANOVA, Conjoint Analysis, Multi-Dimensional Scaling experiment result was analyzed. The result shows that how the control feel is explained by detailed affective variables and what changes have an effect on increasing user's satisfaction of control feel of mobile phone.

Association between sleep duration and impaired fasting glucose according to work type in non-regular workers: data from the first and second year (2016, 2017) of the 7th Korean National Health and Nutrition Examination (KNHANE) (a cross-sectional study)

JaeHan Joo,Jae-Gwang Lee,SangWoo Kim,JaeHan Lee,June-Hee Lee,Kyung-Jae Lee 대한직업환경의학회 2020 대한직업환경의학회지 Vol.32 No.-

Background: We aimed to find the relationship between sleep duration and impaired fasting glucose according to working type in non-regular workers using the 2016 and 2017 Korean National Health And Nutrition Examination (KNHANE, 7th revision). Method: In the 1st and 2nd year (2016, 2017) of the 7th KNHANE, 16,277 people participated. Minors were excluded because this study was intended for individuals aged 19 years and older. As this study was based on wage workers, unemployment, self-employed workers, employers, unpaid family workers, and those who have insufficient answers such as unknown or no response were excluded. Regular workers were excluded because this study was intended for non-regular workers. Finally, a total of 2,168 people were included in the survey, except those who had been diagnosed with diabetes, had a fasting blood glucose level of 126 mg/dL or higher, or taking hypoglycemic agents or receiving insulin injections. To find the relationship between sleep duration and impaired fasting glucose according to work type in non-regular workers, multiple logistic regression analysis was performed by adjusting the general and occupational characteristics after stratification according to work type. All statistical analyses were performed using the SPSS software (version 26.0; SPSS Inc., Chicago, IL, USA). Results: In the case of insufficient sleep duration in irregular female workers, the odds ratio (OR) of impaired fasting glucose was statistically insignificant, but in the case of insufficient sleep duration in irregular male workers who have shift work, the odds ratio (OR) of impaired fasting glucose was significantly higher than that of sufficient sleep duration (Model 1, OR: 3.05, 95% confidence interval [CI]: 1.18–7.90; Model 2, OR: 2.81, 95% CI: 1.08–7.29). Conclusions: Our findings demonstrate that insufficient sleep duration was associated with an increase in fasting blood glucose levels in non-regular male workers working shifts. This means that non-regular workers are in desperate need for adequate sleep and health care. We hope that our study will help improve the health of non-regular workers and more systematic and prospective follow-up studies will be conducted to further improve the health of non-regular workers.

가정용 인버터 에어컨의 사용 환경에 따른 에너지 절감율에 관한 실험적 연구

이상우(Sangwoo Lee),황준(Jun Hwang),주영주(Youngju Joo),조형규(Hyeongkyu Cho),서형준(Hyeongjoon Seo),임병국(Byongguk Lim),임성진(Seongjin Lim) 대한설비공학회 2020 대한설비공학회 학술발표대회논문집 Vol.2020 No.6

Recently, as the situation of using air conditioners for a long time has increased, interest in power consumption consumed by air conditioners has increased. In particular, the interest in electricity bills is higher than ever due to the progressive electricity bills in Korea. In this paper, Evaluate the three methods increasing the set temperature, close unused rooms, and stop driving when going out those can reduced power consumption. Through this, this study provides information for economical use of air conditioners. Under the conditions of this experiment, it was confirmed that the power consumption was reduced by about 11% as the set temperature increased by 1 degree and the power consumption is reduced in proportion to the blocking space by blocking the unused space. Finally when going out for a while,turning on the air conditioner will help save energy.

Characterization of micro-scale creep deformation of an electro-active paper actuator

Lee, Sangwoo,Kim, Joo-Hyung,Kang, Kwangseon,Kim, Jaehwan,Kim, Heung Soo,Yang, Chulho Institute of Physics Publishing 2009 Smart materials & structures Vol.18 No.9

<P>The creep deformation process of an electro-active paper (EAPap) actuator was investigated by adapting stepwise dead-weight loading. To understand the deformation mechanism of the EAPap film, including morphological and structural changes, various loading conditions below yield strength were applied to cellophane EAPap. From the structural observation, micro-dimples and micro-cracks were detected at applied load lower than 10% of yield strength, while they were not found in higher load conditions. It is hypothesized that only short and random fibers in the amorphous region may respond to the applied stress at the low loading condition, not the fibers in the crystalline area. As a result, deformation energy at the localized spot accumulated and created micro-defects at the surface. Meanwhile, fibers in the crystalline region may sustain most of the loads as creep load increases to a high level. Molecular chains in the fiber may rotate and elongate with high load. Elongated fibers were observed only at a high level of load. From the structural change as a function of applied load, a peak shift of crystal orientation was observed only in high load conditions by wide angle x-ray measurement. This may confirm that creep deformation could give rise to structure changes in EAPap. </P>

기능성 위장장애 환자의 소화불량 제증상 치료에 있어서 콤비짐^(�)정의 임상효과

김동의,주재환,추상우,김형륵,조철균,김영진,김현종,김신곤 中央醫學社 1996 中央醫學 Vol.61 No.12

Functional dyspepsia has been considered, until recently, to be a nebulous syndrome, in part because of the lack of a structural explanation for the symptoms and because of the apparent heterogeneity of the patients labeled with this diagnosis. Although many definitions have been offered, there is now reasonable consensus that dyspepsia refers to persistent or recurrent pain or discomfort that is centered on the upper abdomen ; the discomfort may be characterized by postprandial fullness, early satiety, nausea or upper abdominal bloating. The diagnosis of dyspepsia must not be restricted to those with meal-related symptoms because there is no clinical condition, including chronic peptic ulceration, in which the symptoms are exclusively confined to the postprandial period. The majority of the patients with chronic or recurrent dyspepsia do not have a peptic ulcer or any other recognized structural or biochemical abnormality that definitely explains the symptoms ; these patients are classified as having functional dyspepsia. Ideally, therapy for functional dyspepsia should be targeted at correcting an individual's underlying pathophysiologic disturbances. However, the mechanisms that produce symptoms in patients with functional dyspepsia remain poorly understood. A polyvalent digestive product Combizym� has a powerful combination of enzymes with broad activity and broad pH spectrum. It acts from the stomach to the small intestine and has a complete digestive effect on protein, carbohyrate and fat. We treated Combizym� in patients with functional dyspepsia with open, noncomparative study. The results are as follows ; 1. The improvement of the symptoms were 96.4 % in nausea and vomiting, 92.6 % in bloating, other symptoms were also improved over 75 %. 2. There was only mild pruritus in a patient and others were well tolerated during the experiment. 3. Overall improvement rate was 86.7 % of 30 patients. In conclusion, Combizym� is a safe and effective digestive drug in patients with functional dyspepsia.