http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Low-Frequency Noise 측정을 통한 Bottom-Gated ZnO TFT의 문턱전압 불안정성 연구
정광석,김영수,박정규,양승동,김유미,윤호진,한인식,이희덕,이가원,Jeong, Kwang-Seok,Kim, Young-Su,Park, Jeong-Gyu,Yang, Seung-Dong,Kim, Yu-Mi,Yun, Ho-Jin,Han, In-Shik,Lee, Hi-Deok,Lee, Ga-Won 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.7
Low-frequency noise (1/f noise) has been measured in order to analyze the Vth instability of ZnO TFTs having two different active layer thicknesses of 40 nm and 80 nm. Under electrical stress, it was found that the TFTs with the active layer thickness of 80 nm shows smaller threshold voltage shift (${\Delta}V_{th}$) than those with thickness of 40 nm. However the ${\Delta}V_{th}$ is completely relaxed after the removal of DC stress. In order to investigate the cause of this threshold voltage instability, we accomplished the 1/f noise measurement and found that ZnO TFTs exposed the mobility fluctuation properties, in which the noise level increases as the gate bias rises and the normalized drain current noise level($S_{ID}/{I_D}^2$) of the active layer of thickness 80 nm is smaller than that of active layer thickness of thickness 40 nm. This result means that the 80 nm thickness TFTs have a smaller density of traps. This result correlated with the physical characteristics analysis performmed using XRD, which indicated that the grain size increases when the active layer thickness is made thicker. Consequently, the number of preexisting traps in the device increases with decreasing thickness of the active layer and are related closely to the $V_{th}$ instability under electrical stress.
우울증 여부에 따른 경도인지장애 환자의 신경심리학적 특징 비교
정광석(Kwang Seok Jeong),안준호(Joon Ho Ahn),방수영(Soo Young Bhang),최순호(Soon Ho Choi),김성윤(Seong Yoon Kim) 대한노인정신의학회 2012 노인정신의학 Vol.16 No.2
Objectives:The depression in the elderly often accompany with cognitive decline and the mild cognitive impairment (MCI) commonly accompany with depressive symptoms. This study was performed to compare the differences in neuropsychological characteristics between the MCI without depression and the MCI with depression. Methods:The subjects for this study were 366 MCI patient who enrolled through ‘Clinical Research Center for Dementia of South Korea (CREDOS) study’ gathered between December, 2005 and February, 2011. We divided the MCI patient into non-de-pressed group (n=187) and depressed group (n=179), and evaluated each cognitive domain with the Seoul Neuropsychological Screening Battery (SNSB) and analyzed the two group. Results:In the depressed group compared to the non-depressed group, Korean version of Mini-mental State Examination (K-MMSE) scores were lower (p<0.05), and Instrumental Activities of Daily Living (I-ADL) impairment was pronounced (p<0.05). In SNSB, the test scores of the two groups had similar levels on memory (p=0.403), language domain (p=0.098). But the test scores on attention (p<0.05), visuospatial function (p<0.05), executive function (p<0.05) domain in depression group was sig-nificantly lower than in non-depression group. Conclusion:This study shows differences in the clinical feature and neuropsychologic characteristics between the two differ-ent situations. MCI subjects with coexisting depression showed severer cognitive decline and had multiple cognitive domain im-pairment rather than single memory domain impairment.
전자기력 조합에 기초한 평면 구동기를 이용한 자기 부상 방식 초정밀 스테이지
정광석,백윤수,Jeong, Gwang-Seok,Baek, Yun-Su 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.11
In this Paper, we suggest the precision stage using a novel non-contact planar actuator that utilizes an interaction between an array type of air-core solenoids and permanent magnets. The former with axes arranged in the mutually orthogonal direction is fixed on the stator and the latter with the same polar direction is attached below the stage. The promising magnetic structure has little uncertainty such as hysteresis loss caused by ferromagnetic material, then it is simple to quantify the magnetic phenomenon. And all the magnetic forces are transmitted through narrow air-gap between the coil and the permanent magnet, therefore the structure can be highly compacted. Furthermore, the stage or plate can be perfectly isolated from the stator without any wire connection, leading to diminish the generating possibility of wear particles due to mechanical contact. Then. it is estimated that the proposed operating principle is very suitable for work requiring high accuracy and cleanness. or general-purpose nano stage. The main issues rebated to the plate driving are discussed here.
자기 부상 방식 구동원리를 이용한 다자유도 정밀 위치 시스템의 최적 설계, 모델링 및 제어에 관한 연구
정광석,백윤수,Jeong, Gwang-Seok,Baek, Yun-Su 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.5
The multi degree of freedom system using magnetic levitation has been implemented successfully. Differently from another noncontact systems, the developed system was focused on the maximization of the system stiffness under the constraint of a limited input. The variation of a relative adopting point between the magnetic pair, its location on the fixed base, and the selection of optimal specifications for the main active magnetic elements give us another chance to realize the increased robustness against external disturbances with the less control inputs. In this paper, the overall development procedures are given including the optimal design, the dynamic modeling, the various control tests, and the main issues to be solved.
정광석,백윤수,Jeong, Gwang-Seok,Baek, Yun-Su 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.5
In this paper, we introduce a positioner based on magnetic levitation to eliminate the friction which is the most severe effect to limit high resolution on the micro level. Differently from existing electromagnetic device, the proposed positioner consists of air core solenoid and permanent magnet. Although the combination produces small magnetic force, it is suitable for realizing micro motion repeatedly without the accumulation of error because there is no hysteresis caused by ferromagnetic materials, no eddy current loss, no flux saturation. First, the approximate modeling of stiffness and damping effects between the magnetic elements is made and verified experimentally. Then, we have formulated the dynamic equation of one d.o.f magnetic levitation positioner using linear perturbation method and discussed the necessity of optimization for the chief design parameters to maximize the stability performance.
패밀리 레스토랑 이벤트 활동이 고객의 관계지향성과에 미치는 영향
정광석(Kwang Suk Jung),김종원(Chong Won Kim),김정경(Jeong Kyong Kim) 한국호텔외식관광경영학회 2002 호텔경영학연구 Vol.11 No.1
The purpose of this study is as follows; first, to examine systematically visual security of assessment on event activities at the family restaurants and it`s contribution on the inclination of the customer relationship, second, to examine the efficient marketing plans of events at the family restaurants, for maximizing the enterprise profits with efficient management. The data of this study was taken from five foreign brand family restaurants(T.G.I. Friday`s, Bennigan`s, Sizzler, Outback steakhouse, Marche`) run in Seoul, Korea. It was surveyed to every 5th customers who visited from May, 1, 2001 to May, 20, 2001 and December, 20, 2001 to December, 31, 2001 in the family restaurants by an interview method of self-filling up. The results were as followings; Sales service group, low income earner group, young age-group and female group in variability verification of each group by demographic characteristics are perceived highly effect and valuation on event activities. In the difference of each group by use form the groups such as frequent visiting group, group accompanied by friends and family, highly paid group and a benefit club or a graduates` association are perceived highly effect and valuation on event activities. The factors affected to the relationship inclination of the customers, visiting the family restaurants should be embossed customer care factor in the relational quality (satisfaction, credibility) and necessary systematical approach on publicity and guidance factor in the relationship result(repurchase intention, recommendation and support)