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Comparison of Land Surface Temperatures from Near-surface Measurement and Satellite-based Product
Ryu, Jae-Hyun,Jeong, Hoejeong,Choi, Seonwoong,Lee, Yang-Won,Cho, Jaeil The Korean Society of Remote Sensing 2019 大韓遠隔探査學會誌 Vol.35 No.4
Land surface temperature ($T_s$) is a critical variable for understanding the surface energy exchange between land and atmosphere. Using the data measured from micrometeorological flux towers, three types of $T_s$, obtained using a thermal-infrared radiometer (IRT), a net radiometer, and an equation for sensible heat flux, were compared. The $T_s$ estimated using the net radiometer was highly correlated with the $T_s$ obtained from the IRT. Both values acceptably fit the $T_s$ from the Terra/MODIS (Moderate Resolution Imaging Spectroradiometer)satellite. These results will enhance the measurement of land surface temperatures at various scales. Further, they are useful for understanding land surface energy partitioning to evaluate and develop land surface models and algorithms for satellite remote sensing products associated with surface thermal conditions.
Ryu, Jae-Hyun,Hong, Sungwook,Lyu, Sang Jin,Chung, Chu-Yong,Shi, Inchul,Cho, Jaeil The Korean Society of Remote Sensing 2018 大韓遠隔探査學會誌 Vol.34 No.1
The effects of hydro-meteorological and surface variables on the frequency of Asian dust events (FAE) were investigated using ground station and satellite-based data. Present weather codes 7, 8, and 9 derived from surface synoptic observations (SYNOP)were used for counting FAE. Surface wind speed (SWS), air temperature (Ta), relative humidity (RH), and precipitation were analyzed as hydro-meteorological variables for FAE. The Normalized Difference Vegetation Index (NDVI), land surface temperature (LST), and snow cover fraction (SCF) were used to consider the effects of surface variables on FAE. The relationships between FAE and hydro-meteorological variables were analyzed using Z-score and empirical orthogonal function (EOF) analysis. Although all variables expressed the change of FAE, the degrees of expression were different. SWS, LST, and Ta (indices applicable when Z-score was < 0) explained about 63.01, 58.00, and 56.17% of the FAE,respectively. For NDVI, precipitation, and RH, Asian dust events occurred with a frequency of about 55.38, 67.37, and 62.87% when the Z-scores were > 0. EOF analysis for the FAE showed the seasonal cycle, change pattern, and surface influences related to dryness condition for the FAE. The intensity of SWS was the main cause for change of FAE, but surface variables such as LST, SCF, and NDVI also were expressed because wet surface conditions suppress FAE. These results demonstrate that not only SWS and precipitation, but also surface variables, are important and useful precursors for monitoring Asian dust events.
수치해석을 이용한 해양시추용 드릴비트의 구조적 안전성 평가
유찬욱(Ryu canuk),박재현(Park jaehyoun),김정렬(Kim jeongryul),배재일(Bae jaeil) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
A drill bit is the component of the offshore drilling machine for pulverizing the aquifer which is under the abyssal sea to drill for oil and gas. During top drive are spinning, it connect with drill collar, pipe and then also spinning all of them. In this paper, the strength of drill bit are implemented to evaluate to drill bit safety when the abyssal sea which is considered only 1,700m pressure to the drill bit. Additionally, the torque from top drive also applied in this analysis. The drill bit have many kind of types, the previous analysis it chose tungsten carbide type. Base on the analysis results, we conclude that the tungsten carbide type drill bit could perform the drilling aquifer.
Scavenging Effects of Tea Catechins on Superoxide and Hydroxy Radical
Park Jaeil,Liuji Chen,Xianqiang Yang,Shengrong Shen,Yuefei Wang,Ryu Beung Ho 한국생명과학회 2002 Journal of Life Science Vol.12 No.2
Tea catechins, the most important compounds in tea polyphenols, can efficiently scavenge superoxide anion free-radical (O₂-·), hydroxyl radical. (·OH) The mechanism of scavenging active oxygen free radicals was investigated by ESR spin trapping technique and Chemiluminescence. Results showed that various tea catechins constitute an antioxidant cycle in accordance with the decreasing order of the first reductive potential, and produce the effect of cooperative strength each other. Esterificated catechins could scavenge active oxygen free radicals more effectively than the non-esterificated ones. When ·OH and O₂-·- were scavenged by (-)-epigallocatechin gallate [(-)- EGCG], the stoichiometric factors were 6, and the rate constants of scavenging reaction reached 7.71x10(6) and 3.52x10(11) L mmol-¹ S-¹, respectively. In the mean time, tea catechins could scavenge superoxide anion fiee radical (O₂-·) and hydroxyl radical (·OH) in a dose dependent manner. But at higher concentration or pH value, tea catechins can induce the prooxidant.
Na, Domin,Ryu, Jaeil,Hong, Suk-Joo,Hong, Sun Hwa,Yoon, Min A,Ahn, Kyung-Sik,Kang, Chang Ho,Kim, Baek Hyun Korean Society of Magnetic Resonance in Medicine 2016 Investigative Magnetic Resonance Imaging Vol.20 No.2
Purpose: To analyze the feasibility of three-dimensional (3D) diffusion-weighted (DW) PSIF (reversed FISP [fast imaging with steady-state free precession]) sequence in order to evaluate peripheral nerves in the elbow. Materials and Methods: Ten normal, asymptomatic volunteers were enrolled (6 men, 4 women, mean age 27.9 years). The following sequences of magnetic resonance images (MRI) of the elbow were obtained using a 3.0-T machine: 3D DW PSIF, 3D T2 SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) with SPAIR (spectral adiabatic inversion recovery) and 2D T2 TSE (turbo spin echo) with modified Dixon (m-Dixon) sequence. Two observers used a 5-point grading system to analyze the image quality of the ulnar, median, and radial nerves. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each nerve were measured. We compared 3D DW PSIF images with other sequences using the Wilcoxon-signed rank test and Friedman test. Inter-observer agreement was measured using intraclass correlation coefficient (ICC) analysis. Results: The mean 5-point scores of radial, median, and ulnar nerves in 3D DW PSIF (3.9/4.2/4.5, respectively) were higher than those in 3D T2 SPACE SPAIR (1.9/2.8/2.8) and 2D T2 TSE m-Dixon (1.7/2.8/2.9) sequences (P < 0.05). The mean SNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR, but there was no difference between 3D DW PSIF and 2D T2 TSE m-Dixon in all of the three nerves. The mean CNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR and 2D T2 TSE m-Dixon in the median and ulnar nerves, but no difference among the three sequences in the radial nerve. Conclusion: The three-dimensional DW PSIF sequence may be feasible to evaluate the peripheral nerves around the elbow in MR imaging. However, further optimization of the image quality (SNR, CNR) is required.
Park, Youngrong,Ryu, Yeon-Mi,Jung, Yebin,Wang, Taejun,Baek, Yeonggyeong,Yoon, Yeoreum,Bae, Sang Mun,Park, Joonhyuck,Hwang, Sekyu,Kim, Jaeil,Do, Eun-Ju,Kim, Sang-Yeob,Chung, Euiheon,Kim, Ki Hean,Kim, S American Chemical Society 2014 ACS NANO Vol.8 No.9
<P>The detection of colon cancer using endoscopy is widely used, but the interpretation of the diagnosis is based on the clinician’s naked eye. This is subjective and can lead to false detection. Here we developed a rapid and accurate molecular fluorescence imaging technique using antibody-coated quantum dots (Ab–QDs) sprayed and washed simultaneously on colon tumor tissues inside live animals, subsequently excited and imaged by endoscopy. QDs were conjugated to matrix metalloproteinases (MMP) 9, MMP 14, or carcinoembryonic antigen (CEA) Abs with zwitterionic surface coating to reduce nonspecific bindings. The Ab–QD probes can diagnose tumors on sectioned mouse tissues, fresh mouse colons stained <I>ex vivo</I> and also <I>in vivo</I> as well as fresh human colon adenoma tissues in 30 min and can be imaged with a depth of 100 μm. The probes successfully detected not only cancers that are readily discernible by bare eyes but also hyperplasia and adenoma regions. Sum and cross signal operations provided postprocessed images that can show complementary information or regions of high priority. This multiplexed quantum dot, spray-and-wash, and endoscopy approach provides a significant advantage for detecting small or flat tumors that may be missed by conventional endoscopic examinations and bestows a strategy for the improvement of cancer diagnosis.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2014/ancac3.2014.8.issue-9/nn5009269/production/images/medium/nn-2014-009269_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5009269'>ACS Electronic Supporting Info</A></P>
Oh, Dohyeok,Ryu, Jae-Hyun,Oh, Sehee,Jeong, Hoejeong,Park, Jisung,Jeong, Rae-Dong,Kim, Wonsik,Cho, Jaeil The Korean Society of Plant Pathology 2018 Plant Pathology Journal Vol.34 No.3
Crop yield is critically related to the physiological responses and disease resistance of the crop, which could be strongly affected by high temperature conditions. We observed the changes in the growth of barley under higher than ambient air-temperature conditions using a temperature gradient field chamber (TGFC) during winter and spring. Before the stem extension stage of barley growth, Cladosporium sp. spontaneously appeared in the TGFC. The severity of disease became serious under warmer temperature conditions. Further, the stomata closed as the severity of the disease increased; however, stomatal conductance at the initial stage of disease was higher than that of the normal leaves. This was likely due to the Iwanov effect, which explains that stressed plants rapidly and transiently open their stomata before longer-term closure. In this study, we tested three optical methods: soil-plant analysis development (SPAD) chlorophyll index, photochemical reflectance index (PRI), and maximum quantum yield (Fv/Fm). These rapid evaluation methods have not been used in studies focusing on disease stress, although some studies have used these methods to monitor other stresses. These three indicative parameters revealed that diseased barley exhibited lower values of these parameters than normal, and with the increase in disease severity, these values declined further. Our results will be useful in efficient monitoring and evaluation of crop diseases under future warming conditions.