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레이저 빔 프린터 나노가공품의 표면정밀도 향상에 관한 연구
추현식,성백섭 조선대학교 생산기술연구소 2006 生産技術硏究 Vol.28 No.2
Recent advances in high-tech industry and ultra precision machining technology have led to the development of a wide variety of new materials. The demand for LBP Polygon Mirror finishing parts has increased, which are mainly used for the motor of the printer. so ultra precision machining technology is required. It is important for Polygon Mirror to have the enough strength for the highUspeed rotation and high quality Polygon line surface. Polygon Mirror, high-tech nano finishing part, is used for optical instrument such as laser phnters, digital copiers, laser fax machines and bar-code readers, etc. Therefore, we have evaluated the machining precision of matehal surface and tried to determine the optimum machining conditions in order to improve machining precision of S3M. Also we have applied to the production line to reduce the defective proportion. As a result, we have obtained high quality precision of side surface machining in case that the number of revolutions, speed and movement were constant and cutting rate was 0.05 mm. Also we have obtained the same results from the 30 test specimens with constant rough-cutting during the Polygon line machining. The defective proportion decreased from 12 percent to 4-6 percent when the machining conditions selected during the test were applied to the real production line. It is expected that the defective proportion of products can be reduced if we conduct further research on the cleaning and heat treatment process.
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박용구,정상섭,주정화,김종환 대한신경외과학회 1991 Journal of Korean neurosurgical society Vol.20 No.9
Recently, motor evoked potential(MEP) using cortical surface of transcranial stimulation have been used to monitor the integrity of motor pathways and map motor cortex in human and animal. The primary concept using motor evoked potentials(MEPs) for test of motor pathways was based on the assumption that pyramidal neurons in the motor cortex are activated by electrical stimulation applied on the cerebral cortex and synchronized compound action potentials are conducted mainly along the corticospinal tracts in the spinal cord. However, the origins and the descending pathways of these MEPs in small animals may be different from those of potentials evoked by intracortical microstimulation because of current spread. Our previous study revealed that the origns of the MEPs in rats differed from those previously believed and may be reticular nuclei. To further clarify those results and localize the intraspinal pathways conducting MEPs, consecutive vertical and/or horizontal sections of the spinal cord were performed at T9 cord level in twelve rats. MEPs were recorded at T2/3 and L2/3 before and after each section and sequential alterations of MEPs were observed. In six rats, the stimulation was alternated between the right and left cortex and the lateralities of conduction pathways were compared. All six cases showed no differences of MEPs and pattern of wave abolition after each section between right and left brain stimulation. The alteration of MEPs after each consecutive section was categorized by analyzing latency shift, amplitude change, and disappearance of waves. We divided a cross section of T9 spinal cord into forty-six squares. If one of the categorized changes occurred after cutting an area, the appropriate score was given for the area since more change of waves meant more significant contribution of the cut area to conduction of MEPs. The score of twelve rats were summed in each forty-six spots and map showing the distribution of MEPs was constructed. The map revealed that MEPs were conducted along the wide area of ventral and lateral funiculus of the spinal cord but mainly along the medial portion of the ventral funiculus and ventral portion of the lateral funiculus through which reticulospinal and vestibulospinal tracts pass. No conduction of MEPs along the corticospinal tracts was confirmed. This finding supports the result of our previous study. However, this extrapyramidal MEPs conducted along ventral spinal cord in addition to somatosensory evoked potential(SSEP) which is conducted along posterior funiculus can be useful to monitor the integrity of the whole spinal cord. Moreover, the extrapyramidal MEP can be more useful than pyramidal MEP in rats because the reticular formation plays a more important role in motor function and pyramidal tract is located in posterior funiculus.
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Lee, Won‐,Mo,Sung, Ji Ho,Chu, Kanghyun,Moya, Xavier,Lee, Donghun,Kim, Cheol‐,Joo,Mathur, Neil D.,Cheong, S.‐,W.,Yang, C.‐,H.,Jo, Moon‐,Ho WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.10
<P>On page OP49, M.‐H. Jo and co‐workers describe a method of control over photocurrent detection by manipulating ferroelectric domain configurations. The magnitude is spectrally centered around charged domain walls that are associated with oxygen vacancy migration in BiFeO<SUB>3</SUB>, where potential gradients caused by spontaneous polarization yield asymmetric and nonlinear photocarrier dynamics. </P>
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박용구,정상섭,주정화,김종환 대한신경외과학회 1991 Journal of Korean neurosurgical society Vol.20 No.9
Motor evoked potential(MEP) produced by cortical surface or transcranial stimulation has evolved as a new clinical and experimental tool to monitor the integrity of motor pathways and to map motor cortex. Clinical assessment of motor system using MEP has further advanced with recent development of the magnetic stimulator. The primary concept using MEPs test of motor pathways was based on the assumption that pyramidal neurons in the motor cortex are activated by electrical stimulation applied on the cerebral cortex and synchronized compound action potentials are conducted mainly along the corticospinal tracts in the spinal cord. However, recent studies indicated that the origins of the MEPs in non-primates may differ from those previously believed. In order to use MEPs as a clinical or experimental tool, it is essential to clarify the origin of MEPs. Therefore, goals of this study were : ⑴ to investigate the origin of MEPs, and ⑵ to design the most reliable simple method to evoke and monitor MEPs. In a total of fifteen rats, MEPs were produced by cortex to cortex stimulation and were monitored using a pair of epidural electrodes. Using varying stimulus intensities, the amplitudes and latencies of MEPs were statistically analyzed. The latencies and amplitudes of the MEPs in these animals showed surprisingly large standard deviations, which were partially resulted from convergence of neighboring waves during high stimulation intensities. Wave forms of MEPs were also varied greatly depending on the position of recording electrodes. At low stimulus intensities, most consistent MEPs were obtained when the stimulating electrodes were placed on the hard palate and the temporal muscle, not on the motor cortex. This observation indicates that the primary source of MEPs is not the motor cortex in the rat. When the potentials generated by direct stimulation of motor cortex and those generated by reticular nuclei were monitored epidurally sources actually identical in their latencies and wave forms. However, the threshold stimulus intensities evoking these potentials were quite different in the two methods. The threshold was much lower to evoke potentials by reticular nuclei stimulation. It suggests that MEPs are generated by the reticular nuclei or brain structure located in the brain stem. The observation that the motor cortex play no major roles in generation MEPs was confirmed by sequential sections of neural axis from the motor cortex to brain stem in three rats. All these findings suggested that neither direct motor cortex stimulation not transcranial stimulation did evoke MEPs origination from the motor cortex in rat. These stimulating methods activate reticular nuclei by stimulus current spread to the brain stem. Since the reticular formation plays an important role in motor function in rats. MEP originated from reticular nucleus play an important testing of the motor function in rats. Moreover, transcranial stimulation of the brain is technically easy. This technique producing MEPs originated from reticular nucleus can be useful to monitor the integrity of motor pathways.
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A New Infrared Probe Targeting Mitochondria via Regulation of Molecular Hydrophobicity
Sung, June,Rho, Jun Gi,Jeon, Gyeong G.,Chu, Yeonjeong,Min, Jun Sik,Lee, Sanghee,Kim, Jong H.,Kim, Wook,Kim, Eunha American Chemical Society 2019 Bioconjugate chemistry Vol.30 No.1
<P>Herein, we developed a near-infrared (NIR) fluorescent probe for mitochondrial staining based on the NIR fluorochrome, silicon-rhodamine. The hydrophobicity of the fluorescent core was systematically modified by conjugation with 10 different commercial amines. The resulting fluorescent compounds exhibited similar photophysical properties but diverse hydrophobicity. We identified the optimal level of hydrophobicity associated with high mitochondrial targeting efficiency. In particular, the SiR-Mito 8 probe provided excellent mitochondrial staining and successfully differentiated the live Hep3B cancer cells from normal L02 cells <I>in vitro</I>.</P> [FIG OMISSION]</BR>
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Innovative Design and Integrated Manufacturing Laboratory at Seoul National University
Sung-Hoon Ahn,Won-Shik Chu,Varsha Khare,Gil-Yong Lee,Wei Wang,Dong-Hyeon Kim,Sung-Ik Park,Min-Woo Han,Hyun-Taek Lee,Min-Cheol Kim,Jang-Yeob Lee,Hyung-Soo Kim,Min-Soo Kim,Kang-In Lee,Ying Jun Quan,Ji-H 한국생산제조학회 2016 한국생산제조시스템학회 학술발표대회 논문집 Vol.2016 No.10
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컬러감자 홍영, 자영으로부터 항산화 화합물의 정량 및 간세포 보호 효과 탐색
김상민 ( Sang Min Kim ),강경수 ( Kyungsu Kang ),하인수 ( In Su Ha ),노주원 ( Chu Won Nho ),남정환 ( Jung Hwan Nam ),조지홍 ( Ji Hong Cho ),권오근 ( Oh Keun Kwon ),정진철 ( Jin Cheol Jeong ),이재권 ( Jae Kwon Lee ),판철호 ( Cheol H 충북대학교 과학교육연구소 2014 과학교육연구논총 Vol.29 No.1
The colored Potatoes, ‘Hongyoung’ and ‘Jayoung’ cultivars bred in Rural Development Administration (Korea) contain antioxidant compounds such as chlorogenic acids and anthocyanin compounds in the tuber. In this study, main antioxidant compounds in both cultivars were identified by LC-MS analysis and quantified by HPLC analysis. The result showed that three compounds (petunidin-3-O-coumaroyl-rutinoside-5-O-glucoside, pelargonidin-3-Ocoumaroyl- rutinoside-5-O-glucoside and peonidin-3-O-coumaroyl-rutinoside -5-O-glucoside) were identified as main anthocyanins in ‘Jayoung’ cultivar while only pelargonidin-3-O-coumaroyl-rutinoside-5-O-glucoside was presented as a major anthocyanin in ‘Hongyoung’ cultivar. Among chlorogenic acids, 5-O-caffeoylquinic acid was the most abundant in both cultivars. In order to evaluate hepatoprotective activity of these potatoes, the methanol extracts and their serial solvent fractions were prepared by solvent partition and XAD-7 column chromatography method and treated on hepatoma HepG2 cells of which cytotoxicity was induced by tert-butyl hydroperoxide. Among the tested samples, anthocyanin-rich fractions from both cultivars contained the strongest hepatoprotective effect on HepG2 cells. This result indicates that hepatoprotective effect of these fractions can be occurred from anthocyanin.
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임상무,양승대,박찬희,배문선,조철우,윤석남 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.1
Purpose: The aim of this study is to demonstrate the feasibility of 2-[fluorine-18] fluoro-2-deoxy-D-glucose (F-18-FDG) whole body scan (FDG W/B Scan) using dual-head gamma camera equipped with ultra high energy collimator in patients with various cancers, and compare the results with those of coincidence imaging. Materials and Methods: Phantom studies of planar imaging with ultra high energy and coincidence tomography (FDG CoDe PET) were performed. Fourteen patients with known or suspected maligancy were examined. F-18-FDG whole body scan was performed using dual-head gamma camera with high energy (511 keV) collimators and regional FDG CoDe PET immediately followed it. Radiological, clinical follow up and histologic results were correlated with F-18-FDG finding. Results: Planar phantom study showed 13.1 mm spatial resolution at 10 cm with a sensitivity of 2638 cpm/MBq/ml. In coincidence PET, spatial resolution was 7.49 mm and sensitivity was 5351 cpm/MBq/ml. Eight out of 14 patients showed hypermetabolic sites in primary or metastatic tumors in FDG CoDe PET. The lesions showing no hypermetabolic uptake of FDG in both methods were all less than 1 cm except one lesion of 2 cm sized metastatic lymph node. The metastatic lymph nodes of positive FDG uptake were more than 1.5 cm in size or conglomerated lesions of lymph nodes less than 1 cm in size. FDG W/B scan showed similar results but had additional false positive and false negative cases. FDG W/B scan not visualize liver metastasis in one case that showed multiple metastatic sites in FDG CoDe PET. Conclusions: FDG W/B scan with specially designed collimators depicted some cancers and their metastatic sites, although it had a limitation in image quality compared to that of FDG CoDe PET. This study suggests that F-18-FDG positron imaging using dual-head gamma camera is feasible in oncology and helpful if it should be more available by regional distribution of FDG.
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