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Enhancing PV modules efficiency and output power by applied laser patterned glass
Kim Minje,Jeon Youngwoo,Kim Hong-Il,Park Jinjoo 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.11
The power of a PV module afects the amount of incident light collected by the cells. It causes optical loss in the process of modularizing solar cells. Optical loss in the PV module is refected due to refractive index mismatch at the air/glass interface. To reduce the optical loss, we form periodic patterns using a femtosecond laser, which is a non-thermal process and form various patterns through a chemical etching process. The laser patterned glass having a light-trapping structure with a periodic pattern improved transmittance of 1.59% in the visible ray region (380–780 nm) and haze ratio of 55% at 550 nm. Laser patterned glass was applied to the module, and the power was improved by 1.56% with a current gain of 1.56% due to the light-trapping structure.
Kim, Seong Jin,Woo, Youngwoo,Park, Ah-Young,Kim, Hye Rim,Son, Sujin,Yun, Hwi Young,Chun, Pusoon,Moon, Hyung Ryong Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.9
Synthesis of north-5'-methylbicyclo[3.1.0]hexyl adenine and hypoxanthine nucleosides with an ethenyl group at C3' position was successfully achieved by a highly facile method. Methylbicyclo[3.1.0]hexanone (${\pm}$)-7 with three contiguous chiral centers and its epimer (${\pm}$)-6 was remarkably simply constructed only by four steps involving a carbenoid insertion reaction in the presence of rhodium (II) acetate dimer as a metal catalyst, giving a correct relative stereochemistry of the generated three chiral centers. Due to steric hindrance from the concave face of the bicyclo[3.1.0]hexanone system, a Grignard reaction of (${\pm}$)-7 with ethenylmagnesium bromide showed exclusive diastereoselectivity towards the b-face. The Grignard reaction chemoselectively proceeded without reacting with ester functionality. Coupling reaction of glycosyl donor (${\pm}$)-11 with 6-chloropurine nucleobase afforded only the desired $N^9$-alkylated nucleoside without the formation of $N^7$-regioisomer. By the conventional method, 6-chloro group was converted into 6-amino and 6-hydroxy groups to give the desired adenine and hypoxanthine bicyclo[3.1.0]hexyl carbanucleosides with 3'-ethenyl group, respectively.
Youngwoo Nam,Won Il Choi,Hye Jung Song,Kyu Wha Kim 한국응용곤충학회 2015 한국응용곤충학회 학술대회논문집 Vol.2015 No.10
This study was conducted to examine the occurrence characteristics of pine trees infected by pine wood nematode in Gyeongsangbuk-do, Korea. Based on the GPS coordinate data of the infected trees at Yeongdeok-gun from 2013 to 2014 and at Andong-si in 2014, nearest neighbor analysis was conducted to analyze nearest distance between the infected trees. And the influence of geographical factors such as altitude, slope, and the distance from the road on the position of infected trees were identified. Our results showed that over 60% of the newly infected trees were found within 50m of the trees infected in previous year. Over 70% of infected trees occurred below 100m altitude in Yoeongdeok-gun whereas less 32% of total pine trees distributed below the altitude. 98% of the infected trees and 74% of total pine trees in Andong-si were found between 150 and 300m altitude, and altitudinal distribution of the infected trees was similar to that of pine forests. Only less 5% of infected trees found in the forests located below 5 degree of slope in Yeongdeok-gun whereas 18% of total pine trees existed in the areas. Over 50% of infected trees in the forests located from 10 to 20 degree of slope, and 47% of total pine trees were found in the forests located from 5 to 15 degree of slope. Most infected trees and total pine trees were found in the forests located below 15 degree of slope in Andong-si. Over 80% of the infected trees occurred within 1km of road in both study areas.
Kim, Youngwoo,Hong, Byung Woo,Kim, Seung Ja,Kim, Jong Hyo Published for the American Association of Physicis 2014 Medical physics Vol.41 No.7
<P>A major challenge when distinguishing glandular tissues on mammograms, especially for area-based estimations, lies in determining a boundary on a hazy transition zone from adipose to glandular tissues. This stems from the nature of mammography, which is a projection of superimposed tissues consisting of different structures. In this paper, the authors present a novel segmentation scheme which incorporates the learned prior knowledge of experts into a level set framework for fully automated mammographic density estimations.</P>
Vision-based fluid-type tactile sensor for measurements on biological tissues
Kim, Youngwoo,Obinata, Goro,Kawk, Bongseop,Jung, Jiuk,Lee, Suwoong Springer-Verlag 2018 Medical & biological engineering & computing Vol.56 No.2
<P>Hardness, dimensions, and location of biological tissues are important parameters for electronic palpation protocols with standardized performance. This study presents a novel fluid-type tactile sensor able to measure size and depth of heterogeneous substances in elastic bodies. The new sensor is very simple and can be easily fabricated. It consists of an image sensor, LED lights, and a touchpad filled with translucent water. The intensity field of the light traveling in the touchpad is analyzed to estimate the touchpad shape which conforms to the shape of an object in contact. The use of the new sensor for measuring size and depth of heterogeneous substances inside elastic bodies as well as hardness of elastic bodies is illustrated. Results obtained for breast cancer dummies demonstrate the effectiveness of the proposed approach.</P>
YoungWoo Kim,Tatsuo Narikiyo 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-
This paper presents a new controller design method based on the data-mining polynomial algorithm. We show application of a polynomial data-mining algorithm to controller design, where an input-state linearized polynomial vehicle model is developed for a very low speed operation and without introducing any process with fudge factor, control inputs of nonlinear system are obtained in the original coordinate. We verify the developed modeling method and controller design method through some numerical experiments.
Youngwoo Nam,Won IL Choi,Dae-Sung Won,Jong-Kuk Kim,Sang-Hyun Koh,Jung-Su Lee,Kyung-Hee Kim 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.10
An ambrosia beetle, Platypus koryoensis, is a vector of Raffaelea quercimongolicae that is known to cause Korean Oak Wilt (KOW), one of the serious threats to forest healthy in Korea. To manage P. koryoensis properly, it is necessary to clarify flight period of the adult. This experiment was conducted to elucidate the relationship between temperature and the flight period based on field observation in three forests consisted of Quercus mongolica from 2007 to 2009 except winter season. Date of flight period for 50% (FP50) was estimated by the cumulative Weibull distribution model based on cumulative proportion of the adult density and air temperature. Relationship between site temperature and the date of FP50 of P. koryoensis was the most significant when temperatures below 6.5℃ were excluded, suggesting lower threshold temperature for the flight period based on the site temperature. The pooling cumulative proportion of flight period against degree days was well described by the degree-day model, which has explanatory power for the 89% of year and site variation in the flight period and predicted accurately the flight pattern in 2011.