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The nonlinear optical properties of a magneto-exciton in a strained Ga_(0.2)In_(0.8)As/GaAs quantum dot

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Chinese Physics B 2013年第10期22卷 479-485页

作者： N.R.Senthil Kumar A.John Peter Chang Kyoo yoo Department of Physics SBM College of Engineering and Technology Department of Physics Govt.Arts CollegeMelur-625 106MaduraiIndia Center for Environmental Studies/Green Energy Center Deptartment of Environmental Science and EngineeringCollege of EngineeringKyung Hee UniversitySeocheon-dong 1Giheung-guYongin-SiGyeonggi-Do446-701South Korea

The magnetic field-dependent heavy hole excitonic states in a strained ***/GaAs quantum dot are investi- gated by taking into account the anisotropy, non-parabolicity of the conduction band, and the geometrical confinement. The strained quantum dot is considered as a parabolic dot of InAs embedded in a GaAs barrier material. The dependence of the effective excitonic g-factor as a function of dot radius and the magnetic field strength is numerically measured. The interband optical transition energy as a function of geometrical confinement is computed in the presence of a mag- netic field. The magnetic field-dependent oscillator strength of interband transition under the geometrical confinement is studied. The exchange enhancements as a function of dot radius are observed for various magnetic field strengths in a strained ***/GaAs quantum dot. Heavy hole excitonic absorption spectra, the changes in refractive index, and the third-order susceptibility of third-order harmonic generation are investigated in the Gao.2Ino.8As/GaAs quantum dot. The result shows that the effect of magnetic field strength is more strongly dependent on the nonlinear optical property in a low-dimensional semiconductor system.

关键词： oscillator strength exciton quantum dot

Forecasting promising technology using analysis of patent information:Focused on next generation mobile communications

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Journal of Central South University 2014年第11期21卷 4303-4310页

作者： CHOI Seung-Wook YOU Yen-yoo NA Kwan-Sik Department of Knowledge Service & Consulting Hansung UniversitySeoul Korea Department of Management Information Systems Seowon UniversityCheongju Korea

In order to forecast promising technologies in the field of next generation mobile communication, various patent indicators were analyzed such as citation per patent, patent family information, patent share, increase rate, and patent activity. These indicators were quantified into several indexes and then integrated into an evaluation score to provide promising technologies. As a result of the suggested patent analysis, four technologies out of twenty two in details classification were selected, which showed outstanding technology competitiveness, high patent share and increasing rates as well as high recent-patent-ratios and triad-patent-family-ratios. Each of the selected technologies scored more than 10 points in total, and the following four technologies were suggested as promising ones in the field of next generation mobile communication: 1) 3GPP based mobile communication, 2) beyond 4G mobile communication, 3) IEEE 802.16 based mobile communication, which are in medium classification of broadband mobile communication system, and 4) testing/certification system of mobile communication, which is in medium classification of mobile communication testing/certification system.

关键词： next generation mobile communication promising technology forecasting patent information patent analysis patent indicators

Fluid flow and heat transfer characteristics of spiral coiled tube: Effects of Reynolds number and curvature ratio

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Journal of Central South University 2012年第2期19卷 471-476页

作者： yoo Geun-jong CHOI Hoon-ki DONG Wa-ryong School of Mechatronics Changwon National University

Numerical analysis was performed to investigate flow and heat transfer characteristics in spiral coiled tube heat exchanger. Radius of curvature of the spiral coiled tube was gradually increased as total rotating angle reached 12n. As the varying radius of curvature became a dominant flow parameter, three-dimensional flow analysis was performed to this flow together with different Reynolds numbers while constant wall heat flux condition was set in thermal field. From the analysis, centrifugal force due to curvature effect is found to have significant role in behavior of pressure drop and heat transfer. The centrifugal force enhances pressure drop and heat transfer to have generally higher values in the spiral coiled tube than those in the straight tube. Even then, friction factor and Nusselt number are found to follow the proportionality with square root of the Dean number. Individual effect of flow parameters of Reynolds number and curvature ratio was investigated and effect of Reynolds number is found to be stronger than that of curvature effect.

关键词： spiral coiled tube heat exchanger Reynolds number curvature ratio secondary flow friction factor Nusselt number

Multiple-Object Tracking Using Histogram Stamp Extraction in CCTV Environments

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Computers, Materials & Continua 2023年第12期77卷 3619-3635页

作者： Ye-Yeon Kang Geon Park Hyun yoo Kyungyong Chung Division of AI Computer Science and Engineering Kyonggi UniversitySuwon16227Korea Contents Convergence Software Research Institute Kyonggi UniversitySuwon16227Korea

Object tracking,an important technology in the field of image processing and computer vision,is used to continuously track a specific object or person in an *** technology may be effective in identifying the same person within one image,but it has limitations in handling multiple images owing to the difficulty in identifying whether the object appearing in other images is the *** tracking the same object using two or more images,there must be a way to determine that objects existing in different images are the same ***,this paper attempts to determine the same object present in different images using color information among the unique information of the ***,this study proposes a multiple-object-tracking method using histogram stamp extraction in closed-circuit television *** proposed method determines the presence or absence of a target object in an image by comparing the similarity between the image containing the target object and other *** this end,a unique color value of the target object is extracted based on its color distribution in the image using three methods:mean,mode,and interquartile *** Top-N accuracy method is used to analyze the accuracy of each method,and the results show that the mean method had an accuracy of 93.5%(Top-2).Furthermore,the positive prediction value experimental results show that the accuracy of the mean method was 65.7%.As a result of the analysis,it is possible to detect and track the same object present in different images using the unique color of the *** the results,it is possible to track the same object that can minimize manpower without using personal information when detecting objects in different *** the last response speed experiment,it was shown that when the mean was used,the color extraction of the object was possible in real time with 0.016954 *** this,it is possible to detect and track the same object in real time when using the proposed

关键词： Data mining deep learning object detection object tracking real-time object detection multiple object image processing

Computed tomography coronary angiography after excluding myocardial infarction:high-sensitivity troponin versus risk score-guided approach

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World Journal of Emergency Medicine 2023年第6期14卷 428-433页

作者： Won Jae yoo Shin Ahn Bora Chae Won Young Kim Department of Emergency Medicine Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505Republicof Korea

BACKGROUND:Patients with suspected acute coronary syndrome (ACS) in whom myocardial infarction has been ruled out are still at risk of having obstructive coronary artery disease (CAD).This rate is higher among patients with intermediate high-sensitivity troponin I (hsTnI) concentrations (5 ng/L to 99th percentile) than low concentrations (<5 ng/L).Therefore,an intermediate concentration has been suggested as a candidate for downstream investigation with computed tomography coronary angiography(CTCA).We tried to compare the HEART score-guided ***-guided approach for identifying obstructive ***:From a prospective cohort study of patients presenting to the emergency department with suspected ACS,433 patients without elevated hsTnI who also underwent CTCA were selected and *** performances of hsTnI concentration and HEART score were compared using sensitivity,specificity,positive predictive value (PPV),and negative predictive value (NPV).RESULTS:Overall,120 (27.7%) patients had obstructive *** with intermediate hsTnI concentrations were more likely to have obstructive CAD than those with low hsTnI concentrations(40.0%vs.18.1%);patients with non-low-risk HEART scores (≥4 points) were also more likely to have obstructive CAD than those with low-risk scores (0 to 3 points)(41.0%vs.7.6%).The HEART score had higher sensitivity and NPV for detecting obstructive CAD in each classification than hsTnI concentration (sensitivity:89.2%vs.63.3%;NPV:92.4%vs.81.9%,respectively).CONCLUSION:After excluding myocardial infarction in patients with suspected ACS,adding the HEART score for selecting candidates for CTCA could improve patient risk stratification more accurately than relying on hsTnI concentration.

关键词： Chest pain Coronary artery disease Acute coronary syndrome Troponin HEART score

Defect-rich spinel ferrites with improved charge collection properties for efficient solar water splitting

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Journal of Advanced Ceramics 2023年第3期12卷 612-624页

作者： Runfa Tan yoo Jae Jeong Qu Li Minje Kang In Sun Cho Department of Materials Science&Engineering Ajou UniversitySuwon 16499Republic of Korea Department of Energy Systems Research Ajou UniversitySuwon 16499Republic of Korea

Spinel zinc ferrite(ZnFe_(2)O_(4),ZFO)is a potential photoanode material for photoelectrochemical(PEC)water splitting because of its ideal bandgap(1.9–2.1 eV)and superior chemical stability in aqueous ***,the low charge collection efficiency significantly hinders the improvement in PEC ***,we report an ultrafast and effective flame activation route to enhance the charge collection properties of ***,high-temperature flame(>1300℃)facilitated surface and grain boundary diffusions,increasing the grain size and connectivity of the ZFO ***,the reducing atmosphere of the flame enabled the formation of surface defects(oxygen vacancy and Fe^(2+)),thereby increasing the charge carrier density and surface adsorption ***,these two factors promoted charge transport and transfer kinetics,resulting in a 10-fold increase in the photocurrent density over the unactivated ***,we deposited a thin Al_(2)O_(3)overlayer to passivate the ZFO surface and then the NiFeOx oxygen evolution catalyst(OEC)to expedite hole injection into the *** surface passivation and OEC deposition led to a remarkable photocurrent density of~1 mA/cm^(2)at 1.23 V versus the reversible hydrogen electrode,which is the highest value among all reported ZFO ***,the NiFeOx/Al_(2)O_(3)/F-ZFO photoanode achieved excellent photocurrent stability over 55 h(96%retention)and superior faradaic efficiency(FE>94%).Our flame activation method is also effective in improving the photocurrent densities of other spinel ferrites:CuFe_(2)O_(4)(93 times),MgFe_(2)O_(4)(16 times),and NiFe_(2)O_(4)(12 times).

关键词： spinel ferrites flame activation defect-rich surface charge collection photoelectrochemical(PEC) water splitting

Inverse correlation between gastroesophageal reflux disease and atrophic gastritis assessed by endoscopy and serology

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World Journal of Gastroenterology 2022年第8期28卷 853-867页

作者： yoo Min Han Su Jin Chung Seokha yoo Jong In Yang Ji Min Choi Jooyoung Lee Joo Sung Kim Department of Internal Medicine and Healthcare Research Institute Seoul National University Hospital Healthcare System Gangnam CenterSeoul 06236South Korea Department of Anesthesiology and Pain Medicine Seoul National University College of MedicineSeoul 03080South Korea Department of Internal Medicine and Liver Research Institute Seoul National University College of MedicineSeoul 03080South Korea

BACKGROUND Helicobacter pylori(***)infection is known to prevent the occurrence of gastroesophageal reflux disease(GERD)by inducing gastric mucosal ***,little is known about the relationship between atrophic gastritis(AG)and *** To confirm the inverse correlation between AG and the occurrence and severity of *** Individuals receiving health checkups who underwent upper gastrointestinal endoscopy at Seoul National University Healthcare System Gangnam Center were *** grade of reflux esophagitis was evaluated according to the Los Angeles *** AG(EAG)was categorized into six *** AG(SAG)was defined as pepsinogen I≤70 ng/m L and pepsinogen I/II ratio≤*** association between the extent of EAG and SAG and the occurrence and severity of GERD was evaluated using multivariate logistic regression *** In total,4684 individuals with GERD were compared with 21901 healthy *** multivariate logistic regression analysis,advanced age,male sex,body mass index>23 kg/m2,presence of metabolic syndrome,current smoking,and alcohol consumption were associated with an increased risk of *** for *** immunoglobulin G antibodies was associated with a decreased risk of *** was an inverse correlation between the extent of EAG and occurrence of GERD:Odds ratio(OR),1.01[95%confidence interval(CI):0.90-1.14]in C1,0.87(0.78-0.97)in C2,0.71(0.62-0.80)in C3,0.52(0.44-0.61)in O1,0.37(0.29-0.48)in O2,and 0.28(0.18-0.43)in ***,the extent of EAG showed an inverse correlation with the severity of *** presence of SAG was correlated with a reduced risk of GERD(OR=0.49,95%CI:0.28-0.87,P=0.014).CONCLUSION The extent of EAG and SAG exhibited strong inverse relationships with the occurrence and severity of *** followed by *** infection may be independently protect against GERD.

关键词： Gastroesophageal reflux disease Reflux esophagitis Helicobacter pylori Atrophic gastritis Pepsinogen

Synthesis, characterization and electrocatalytic studies of palladium–manganese oxyhydroxide nanocomposite towards direct ethylene glycol fuel cell

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Chinese Science Bulletin 2014年第27期59卷 3413-3419页

作者： Ramanujam Kannan Ae Rhan Kim Dong Jin yoo R&D Education Center for Specialized Graduate School of Hydrogen and Fuel Cells Engineering Chonbuk National University Chonju Joellabuk-do 561-756 Korea Department of Energy Storage/Conversion Engineering Hydrogen and Fuel Cell Research Center Graduate SchoolChonbuk National University Chonju Joellabuk-do 561-756Korea Department of Chemistry Chonbuk National UniversityChonju Joellabuk-do 561-756 Korea

The palladium nanoparticle grafted manganese oxyhydroxide nanorod(MON) electrocatalyst has been synthesized and tested for the electrooxidation of ethylene glycol(EG) in an alkaline medium. The MON was prepared using the hydrothermal method and the Pd nanoparticles were coated on the MON using an in situ reduction method. The nanocatalyst thus prepared was characterized by powder X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and electrochemical methods. The microscopic studies confirm the formation of MON and reveal that the Pd nanoparticles were grafted uniformly on the MON. In the voltammetric studies, the Pd/MON catalyst exhibited a six-fold improved peak current for ethylene glycol electrooxidation compared with the C/Pd. The EG electrooxidation reaction performances of the Pd/MON nanocatalyst in the alkaline solutions containing different quantities of EG were tested through cyclic voltammetry. The catalytic removal of the poisonous intermediates formed during electrooxidation of EG was explained. The present study shows that MON can act as an active support for the Pd nanocatalyst.

关键词：钯纳米粒子氢氧化锰乙二醇化学研究燃料电池纳米复合合成高分辨透射电子显微镜

Comparison of microwave and conventional heating on physicochemical properties and phenolic profiles of purple sweetpotato and wheat flours

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Food Bioscience 2022年第2期46卷 923-933页

作者： Rongbin Cui Michelle Ji Yeon yoo Fan Zhu School of Chemical Sciences University of AucklandPrivate Bag 92019Auckland 1142New Zealand School of Science Faculty of Health and Environment SciencesAuckland University of TechnologyAucklandNew Zealand

The hydrothermal treatment assisted with microwaves on physicochemical properties and phenolic profiles of purple sweetpotato flour and wheat flour was studied and compared with those of conventional heat *** treatments significantly decreased the enthalpy change,pasting viscosity and gelling capacity of flours,while increasing particle size,gelatinization temperatures and content of resistant *** induced more severe damages on the starch granule morphology and crystallinity than conventional heat treatment,which could be attributed to the intensive friction and collision produced by electromagnetic *** total concentrations of hydroxycinnamic acid derivatives and anthocyanins in purple sweetpotato flour extracted using microwaves at 100℃ were 36%and 68%higher than those in the samples after conventional heat treatment at 100℃,*** waves caused a higher extent of cell damage due to sudden temperature rise during microwave ***,microwave treatment has potential to produce novel functionalities and nutritional values of flours and can be applied as an effective approach for other starch-based food products.

关键词： Ipomoea batatas Microwave heating Conventional heating Dielectric property Phenolics Resistant starch Cereal processing Starch gelatinization Domestic cooking