http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
MEE법으로 성장한 InAs/GaAs 양자점의 발광특성
오재원,변혜령,류미이,송진동,Oh, Jae Won,Byun, Hye Ryoung,Ryu, Mee-Yi,Song, Jin Dong 한국진공학회 2013 Applied Science and Convergence Technology Vol.22 No.2
Migration-enhanced epitaxy 성장한 InAs/GaAs 양자점(quantum dots)의 광학적 특성을 PL (photoluminescence)과 Time-resolved PL 이용하여 분석하였다. InAs 양자점은 In을 9.3초 공급하고 5초 차단한 후 As을 3초, 4초, 6초, 또는 9초 공급하고 5초 차단하는 과정을 3회 반복하여 성장하였다. As을 3초 공급한 시료의 PL 피크는 1,140 nm에서 나타나고, PL 세기는 다른 세 시료에 비해 매우 약하게 나타났다. As 공급시간을 3초에서 증가하였을 때 모든 PL 피크는 1,118 nm로 청색이동하여 나타났으며, PL 세기는 증가하였다. As을 6초 공급한 시료의 PL 세기가 가장 강하게 나타나고, 반치폭(full width at half maximum)도 가장 좁게 나타났다. 이러한 결과는 양자점의 밀도와 균일도(크기변화)로 설명된다. 또한 발광파장에 따른 PL 소멸시간은 PL 피크 근처에서 가장 길게 나타났다. The luminescence properties of InAs/GaAs quantum dots (QDs) grown by a migration enhanced epitaxy method have been investigated by using photoluminescence (PL) and time-resolved PL measurements. The MEE method supplies materials in a series of alternate depositions with migration enhancing time between each deposition. After In source was supplied for 9.3 s, the growth was interrupted for 5 s. Subsequently, As source was open for 3 (AT3), 4(AT4), 6 (AT6), or 9 s (AT9), and the growth was interrupted for 5 s again. This growth sequence was repeated 3 times for the growth of InAs QDs. The PL peak of the AT3 was 1,140 nm and the PL intensity was very weak compared with that of the other three samples. The PL peak of all samples except the AT3 sample was 1,118 nm, which is blueshifted from 1,140 nm, and the PL intensity was increased compared to that of the AT3. These results can be explained by the increased QD density and the improved QD uniformity. The AT6 sample showed the strongest PL intensity and the narrowest full width at half maximum. The PL decay time of AT6 increased with increasing emission wavelength from 940 to 1,126 nm, reaching a maximum decay time of 1.09 ns at 1,126 nm, and then decreased as the emission wavelength was increased further.
이혜련(Hyeryeon Yi),신미경(Mee-Kyung Shin),원종순(Jongsoon Won) 기본간호학회 2012 기본간호학회지 Vol.19 No.4
Purpose: The purpose of this study was to investigate sleep patterns and predictors of excessive daytime sleepiness (EDS) in university students. Methods: Participants were 120 university students who were attending two universities in S-city and C-city. Data were collected from May 20 to June 15, 2012 using self-report questionnaires which included Johns’Epworth Sleepiness Scale, Yi’ Sleep Quality Scale, and Beck Depression Inventory. Data were digitalized and analyzed using frequency, percentages, means and standard deviations, Wilcoxon rank sum test, Chi-square test, Fisher’ exact test, and multiple logistic regression with SAS 9.0. Results: Mean total sleep time was 6.6 hours on weekdays, 8.1 hours on weekends. Mean sleep latency was 19.1 minutes and the score for mean sleep quality was 22.6. Prevalence of EDS was 12.5%. Depression was significantly different between EDS and Non-EDS students (t=2.17, p=.030). Multiple logistic regression showed that the only factor associated with EDS was depression (adjusted odds ratio of depression=5.33, 95% Confidence Interval=1.49-19.04). Conclusion: Results of this study indicate that university students experience short sleep time, low sleep quality, and common EDS with depression, suggesting that students with complaints of EDS should be completely assessed for depression as well as sleep problems.
고층 타워에 작용하는 동적 풍압력의 POD 방법을 이용한 시공간적 특성 해석
이미화,함희정 江原大學校 産業技術硏究所 2004 産業技術硏究 Vol.24 No.B
The wind and wind-induced dynamic wind pressures fluctuate irregularly according to time and space. In this study, the proper orthogonal decomposition(POD) technique is applied to wind pressures acting on a tall tower model, and the following results are found: the along-wind and across-wind forces can be reconstructed by only four dominant POD modes, and the reconstructed errors are 4.71% and 22%, respectively for across-wind and along-wind directions. The physical meanings for dominant modes are also presented in the paper. The POD analysis can compress complex wind pressure data only by a few dominant modes and interpret spatio-temporal characteristics of wind pressure by novel way while existing statistical methods do not have such benefits.
열공형과 비열공형 피질하 혈관성 치매에서 위험인자의 차이에 관한 비교 연구
배희준,정지향,유경호,나덕렬,김상윤,최경규,양동원,손의주,이상도,김재우,박경원,김응규,이재홍,박미영,한일우,함동석,최문성,하충건,최성혜,이애영,이병철,한설희 대한치매학회 2003 Dementia and Neurocognitive Disorders Vol.2 No.2
Backgrounds and Objectives: Vascular dementia is a group of dementing disoders arising from various stroke syndrome. Among these. subcortical ischemic vascular dementia (SIVD) is regarded as a relatively distinct clinical entity. However, MRI patterns of SIVD are not homogenous. In some patients, lacunes are dominant, and in others, subcortical white matter changes are. This study was designed to compare risk factor profiles between SIVD with and without multiple lacunes. Methods: We divided 47 subjects (22 males, mean age. 68 years) recruited from VADAPET (Multicenter Trial For Evaluation Of The Changes In the PET Images Of Subcortical Vascular Dementia Patient) study into two groups one with more than 5 lacunes in deep gray matter (lacune group) and the other with 5 or less(non-lacune group) Clinical characteristics and laboratory findings of two groups were compared. Results: Nineteen of 47 patients (40%) belonged to the lacune group. The lacune and non-lacune groups d d not differ in the following variables: age, hypertension, diabetes mellitus, hyperlipidemia heart disease, history of stroke or TIA, history of trauma or major surgery, family history of hypertension stroke, or dementia, age at diagnosis of dementia, body mass index, white blood cell count, ESR, CRP, fibrinogen, hemoglobin A1C, total cholesterol. LDL cholesterol creatinine, proteinuria, glucosuria, and microhematuria. However, male sex, smoking alcohol. hemoglobin, and HDL cholesterol were possibly associated more with lacune group SIVD than with non-lacune group (p<0 1) Multivariate analyses revealed that smoking, hemoglobin, and HDL cholesterol were independent predictors of SIVD with multiple lacunes Conclusion: Our study suggests that SIVD with multiple lacunes may be significantly different in smoking habits hemoglobin, and HDL cholesterol from SIVD without multiple lacunes.
Mee-Yi Ryu,E. A. Moore,R. L. Hengehold,T. D. Steiner,Y. K. Yeo 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
Electrical activation studies of Si-implanted AlxG1ကxN grown on sapphire substrate have been made as a function of ion dose, anneal temperature, and anneal time. The samples were annealed from 1200 to 1350 C with a 500 A thick AlN cap in a nitrogen environment. The optimum anneal temperature for Al0:25Ga0:75N samples implanted with a dose of 1 1015 cmက2 is around 1350 C, exhibiting nearly 87 % electrical activation eciency. Both the electrical activation eciency and Hall mobility of Si-implanted Al0:18Ga0:82N annealed at 1200 C from 5 to 25 min increase continuously with anneal time, but at a much slower rate as anneal time increases. The activation eciencies of 94 and 89 % were obtained for doses of 1 1015 and 5 1014 cmက2, respectively, after annealing at 1200 C for 25 min, which are the highest activation eciency reported for a given dose, to the best of our knowledge.
Ferromagnetic Properties of Nickel-Implanted Al0.35Ga0.65N
Mee-Yi Ryu,Jeremy Raley,Pan Wu,Robert Hengehold,Yicheng Lu,Yung Kee Yeo 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.5
Magnetic characterization studies of Ni-implanted Al$_{0.35}$Ga$_{0.65}$N have been made for various magnetic fields and sample temperatures by using a superconducting quantum interference device (SQUID). Ni ions were implanted at 200 keV to a dose of 3 $\times$ 10$^{16}$ cm$^{-2}$ at room temperature. The material was found to show clear signs of ferromagnetism after annealing between 675 and 775 $^\circ$C for 5 min. The ferromagnetic property persisted above room temperature, and a coercive field width of 118 Oe and a remanent field of 16 \% of the saturation magnetization of 2.6 $\times$ 10$^{-5}$ emu were obtained at 300 K after annealing at an optimum annealing temperature of around 750 $^\circ$C. This ferromagnetic property was also confirmed with field-cooled and zero-field-cooled magnetization measurements, and the Curie temperature was estimated to be around 350 K. Cathodoluminescence and X-ray diffraction (XRD) measurements showed that the significant implantation-related damage was recovered after annealing at 750 $^\circ$C, indicating a good Ni incorporation in the Al$_{0.35}$Ga$_{0.65}$N. Furthermore, the XRD measurements also showed no indication of secondary phase formation or Ni clusters, which implies that we had observed a dilute ferromagnetic semiconductor behavior.
Mee-Yi Ryu,C. Q. Chen,J. H. Song,M. Asif Khan 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.1I
Photoluminescence (PL) and time-resolved PL measurements have been carried out in the quaternary AlxInyGa1.x.yN epilayers grown by using pulsed metalorganic chemical vapor deposition (PMOCVD). PMOCVD-grown AlInGaN layers show a strong blueshift and linewidth broadening of the emission band with excitation power density, and the PL decay time increases with decreasing emission energy. These results are characteristic of localized carrier/exciton recombination, which is beneficial for strong spontaneous emission for ultraviolet (UV) light-emitting diodes (LEDs). The obtained properties indicate that quaternary AlInGaN is a promising material for UV applications and especially that the PMOCVD process is a useful method for fabricating the active region of a deep UV LED.:10chh9