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기능 하중 하에서 접착용 Glass Ionomer 시멘트의 결합강도에 대한 비교연구
전중현,강우진,이근우,Jun Joong-Hyun,Kang Woo-Jin,Lee Keun-Woo 대한치과보철학회 1992 대한치과보철학회지 Vol.30 No.2
The purpose of this study was to compare the bond strength of the glass ionomer luting cements after the functional loads were applied to the crowns respectively 10 min, 30 min, 1 hr, 24 hrs later after mixing of cements. The conventional (GC Fuji I; GC Int. Co., Japan), water hardening type (Ketac Cem; ESPE, W. Germany) glass ionomer luting cement and C-dent ZPC (Confi-Dental Products Co., U.S.A.) as a control were used. The results of this study were obtained as follows: 1. In the bond strength of GC Fuji I, 24 hr-group was highest and there were no statistically significant differences among 10 min-, 30 min- and 1 hr- groups. 2. l3 the bond strength of Ketac Cem and C-dent ZPC, there was no statistically significant differences among 10 min-, 30 min-, 1 hr- and 24 hr-groups respectively. 3. Comparing the bond strength among cements in 10 min-, 30 min-groups respectively, GC Fuji I was lowest and there was no statistically significant difference between Ketac Cem and C-dent ZPC. 4. The bond strengths between GC Fuji I and Ketac Cem were not significantly different in 1 hr-, 24 hr-group. 5. The bond strengths among 3 types of cements were not significantly different in 24 hr-groups.
전중현,현창호 한국지능시스템학회 2017 한국지능시스템학회논문지 Vol.27 No.6
본 논문은 공-판 제어시스템을 제작하고 구동과정에서 발생하는 외란을 고려한 강인 적응제어 기법을 제안한다. 비젼센서를이용한 공-판 제어시스템을 제작하고 이에 대한 수학적 모델링을 먼저 유도한다. 모델기반의 궤환선형화 제어기를 모의실험과정을 거쳐 설계하고, 이를 시스템에 적용하여 구동 시 발생하는 외란과 파라미터 불확실성을 확인한다. 이 과정에서확인된 외란과 파라미터 불확실성을 극복하기 위한 강인 적응제어기 설계기법을 제안한다. 설계한 강인 적응제어기의안정성은 리아푸노프 안정성 이론을 통해 입증하고, 그것의 실용성은 모의실험과 실제 실험에서 먼저 설계한 궤환선형화제어기의 성능비교를 통해서 제안한 제어기의 성능을 검증한다 In this paper, we propose a robust adaptive control method considering the disturbance generated during the driving process by fabricating the ball-plate control system. A ball-plate control system using a vision sensor if fabricated and mathematical modeling is first derived. A model-based feedback linearization controller is designed through a simulation process and applied to the system to check disturbance and parameter uncertainty during operation. We propose a robust adaptive controller design technique to overcome the disturbance and parameter uncertainties identified in the process. The stability of the designed robust adaptive controller is verified through the theory of Lyapunov stability and its practicality is verified by comparing the performance of the feedback linearization controller designed in the simulation and the actual experiment
[18F]Aryl fluorides from hypervalent iodine compounds
전중현,손정민,박준영,윤미진 대한방사성의약품학회 2017 Journal of radiopharmaceuticals and molecular prob Vol.3 No.1
Nucleophilic aromatic fluorination has been one of the most explored methods in fluorin-18 based radiochemistry. Unlike electrophilic [18F]fluorination methods, no-carrier-added nucleophilic radiofluorination with cyclotronproduced [18F]fluoride ion offers better specific radioactivity which is essential aspect to obtain good quality images from positron emission tomography. Contrary to amenable aliphatic radiofluorination, the development of reliable aromatic [18F]fluorination methods has been pursued by many research groups; however, no viable method has yet been established. Recently, hypervalent iodine compound draws increasing attention as versatile radiolabeling precursor for various [18F]fluoroarenes, since it bears the capacity to introduce fluorine-18 either on electron-deficient or electron-rich aryl ring with enhanced regiospecificity. Other classes of hypervalent iodine congeners often utilized in radiochemistry are iodylarenes, iodonium ylides, and spirocyclic iodonium ylides. Recently developed spirocyclic iodonium ylides have already been avidly employed to provide various [18F]aryl fluorides with high labeling efficiency. This metal-free protocol would afford efficient routes, replacing the traditional approaches to [18F]fluoroarenes, from prosthetic labeling synthons to complex PET radiotracers. J Radiopharm Mol Probes 3(1):3-14, 2017
Organometallic fluorine-18 bonds in 18F-radiochemistry
전중현,이민주,전성원,손정민 대한방사성의약품학회 2021 Journal of radiopharmaceuticals and molecular prob Vol.7 No.1
Fluorine-18 is by far the most widely exploited radionuclide in PET (positron emission tomography) radiochemistry. The physical half-life of fluorine-18 allows for chemical manipulation within a restricted timeframe, and cyclotron-produced fluoride ion has been widely applied in aliphatic and aromatic nucleophilic radiofluorinations to produce a variety of established radiotracers. Radiotracers have become more structurally complicated to address diverse targets in physiobiological systems. There is therefore an unmet need to complement traditional C-18F bond-forming radiofluorination with new and efficient radiolabeling techniques to tackle the myriad of possible chemical environments. This review discusses recent advances in organometallic fluorine-18 bond creation in 18F-radiochemistry. Although not widely employed, new radiolabeling strategies for constructing boron-18F, silicon-18F, aluminum-18F, and other metal-18F bonds are described in view of their potential use in the development of novel radiopharmaceuticals.
Pulsed Nd : YAG 레이저를 조사한 임플란트를 가토복강내에 이식시 주위조직에 미치는 영향
전중현,이호용,Jun, Joong-Hyun,Lee, Ho-Yong 대한치과보철학회 1996 대한치과보철학회지 Vol.34 No.4
Pulsed Nd : YAG laser has been used to treat various soft tissue lesions. However, there have been warnings of using laser to treat peri-implantitis because the laser can alter the surface of implant and can rise its temperature so that it might be harmful to implant itself and its surrounding tissue. However, the study in vivo has not been done yet. The purpose of this study was to evaluate the biocompatibility to the pulsed Nd:YAG lased dental implant. 16 HA coated implants and 16 titanium plasma sprayed implants were used. They were divided 4 groups as unlased control, 0.3 watt, 1.0 watt and 2.0 watt lased groups after lasing. And they were implanted in the peritonial walls of 12 rabbits. The rabbits were sacrificed 6 weeks after implantation and the LM and EM specimems were made. 1. In the unlased implant group, both HA coated and titanium plasma sprayed implants were surrounded by fibroblasts and collagen fibers. No macrophages and inflammatory cells were seen. 2. In HA coated implants 0.3 watt, 1.0 watt lased group had a little inflammation, but in 2.0 watt lased group had scattered macrophages, a significantly larger number of chronic imflammatory cells were seen. 3. In titanium plasma sprayed implant 0.3 watt, 1.0 watt lased group had a little inflammation, but in 2.0 watt group had severe inflammation as in the conditions of HA coated group. 4. The inflammatory reaction of both lased HA coated and titanium plasma sprayed implant groups increased as the increase of the power of the laser.