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      • 신경근전기자극에 의한 척수운동신경원의 흥분성 변화

        이정우,김태열,이인학,이준희,Lee, Jeong-Woo,Kim, Tae-Youl,Lee, In-Hak,Lee, Joon-Hee 대한임상전기생리학회 2003 대한임상전기생리학회지 Vol.1 No.1

        The purpose of this study was to determine the effect of neuromuscular electrical stimulation(NMES) on the alteration of spinal motor neuron excitability. In this article, I would like to experiment on a standard capacity of clinical electrophysiology, a difference in applying methods and a clinical efficiency of NMES by Nerve conduction velocity. We used normal eight subjects without neuromuscular disease and all subjects participated 3 session, which at least 1 week between session. Participants classified according to each group in Antagonist, Agonist, Antagonist-Agonist by the NMES. The test was measured continuously pre test, post-test, post 20 minute test by EMG including H reflex, F wave, motor nerve conduction velocity(MNCV). The following results were obtained; 1. H-reflex latencies and H/M intervals were significantly increased in agonist and antagonist-agonist group(p<.01). 2. H-reflex amplitudes and H/M ratios were significantly decreased in agonist and antagonist-agonist group(p<.01). In agonist group, H-reflex amplitudes and H/M ratios were more significantly decreased than antagonist group. 3. F-wave latencies were significantly increased in agonist and antagonist-agonist group(p<.01). F/M intervals were significantly increased in antagonist-agonist group(p<.01). F wave conduction velocities were significantly increased in agonist and antagonist-agonist group(p<.01) but F/M ratios were not significant. 4. MNCV were significantly decreased in agonist(p<.01). These results lead us to the conclusion that agonist and Antagonist-agonist was significantly decreased excitability of spinal motor neuron. Conversely, Antagonist does not decreased. Therefore, A further direction of this study will be to provide more evidence that NMES have an effect on excitability of spinal motor neurons in UMN syndrome.

      • KCI등재
      • KCI등재

        유두상 혈관내막 증식증의 임상적 보고

        이정우,정호윤,이석종,김귀락,최강영,양정덕,조병채,Lee, Jeong-Woo,Chung, Ho-Yun,Lee, Seok-Jong,Kim, Gui-Rak,Choi, Kang-Young,Yang, Jung-Dug,Cho, Byung-Chae 대한성형외과학회 2010 Archives of Plastic Surgery Vol.37 No.3

        Purpose: Intravascular papillary endothelial hyperplasia (IPEH), also known as Masson's pseudoangiosarcoma, is a rare disease which is now considered as a reactive process of the endothelium rather than a benign neoplasm. It can occur in any blood vessels in the body but more common in the head and neck region as a solitary, often tender, bluish or reddish nodule. IPEH is characterized by the development of endothelial-lined papillary projections in a vascular lumen, usually associated with thrombotic material, the endothelial cells in the papillary structures showing only slight atypia and occasional mitotic Figures, the absence of tissue necrosis. Methods: 8 patients with IPEH were enrolled in the study from 2002 to 2007. All 8 lesions were surgically excised for histopathologic diagnosis. Results: 4 patients were female. The duration of the lesions ranged from 3 months to 15 years. The tumors were first noted between the ages of 20 and 72 years. 4 patients had lesions on the head; 2 on the toe; 1 on the back; and 1 on the finger, respectively. All lesions were solitary, ranged in size from 2 mm to 27 mm. There were no recurrences. Conclusion: The clinical appearance of IPEH is not specific, presented as a primary neoplasm, and the diagnosis can be established by microscopic examination. Complete surgical excision is the best choice of therapy for patients with IPEH, and is both diagnostic and curative. Awareness of this lesion will prevent incorrect diagnosis and overly aggressive treatment.

      • KCI등재

        고무댐에 적용하기 위한 유리섬유보강 복합재료 클랩핑 플레이트의 내구 특성

        이정우,박찬기,김종옥,이승기,김필식,Lee, Jeong-Woo,Park, Chan-Gi,Kim, Jong-Ok,Lee, Seung-Kee,Kim, Pil-Sik 한국농공학회 2011 한국농공학회논문집 Vol.53 No.5

        Steel clapping plate is used to connecting rubber body in rubber dam. However, once the steel clapping plate corrodes, it may cause faults, such as the same problems experienced by typical reinforcing steel. This study evaluated the applicability of glass fiber reinforced polymer composite(GFRP) clapping plate as a substitute for steel clapping plate. Absorption and load test were conducted to evaluate the decrease in durability of GFRP clapping plate exposed to deterioration environments. In the durability test results, the absorption rate of GFRP clapping plate was appeared as 0.6~1.0% in 50 day of immersion time. Also, the fracture load decreased with accelerated degradation environment exposure. Moreover, the absorption rate in GFRP clapping plate increased as degradation progressed, reducing the fracture load.

      • KCI등재

        세기변조방사선치료 선량분포 확인을 위한 2차원적 이온전리함 배열의 특성분석

        이정우,홍세미,김연래,최경식,정진범,이두현,서태석,Lee, Jeong-Woo,Hong, Se-Mie,Kim, Yon-Lae,Choi, Kyoung-Sik,Jung, Jin-Beom,Lee, Doo-Hyun,Suh, Tae-Suk 한국의학물리학회 2006 의학물리 Vol.17 No.3

        본 연구의 목적은 2차원적 이온전리함 배열의 특성을 분석하고 세기변조방사선치료 선량분포 확인의 유용성을 평가하기 위함이다. 본 실험에 사용된 2차원적 이온전리함 배열(MatriXX, Scanditronix-Wellhofer, IBA, Germany)은 $24{\times}24cm^2$ 범위에 1,024개의 평판형 전리함(용적: $0.08cm^3$, 직경: 4.5 mm, 높이: 5 mm, 배열간격: 7.62 mm)이 일정한 간격으로 배열되어있다. MatriXX의 특성분석을 위해 선량 직선성, 선량률 의존도, 출력 계수, 단기 선릉재현성을 분석하였으며, 선량분포 확인의 신뢰도를 평가하기 위해 Varian사의 동적쐐기와 세기변조 방사선치료의 선량분포를 분석하였다. 선량 직선성의 범위는 $1{\sim}800$cGy이었으며, 1% 미만의 오차율을 보였다. 선량률 의존성(범위 $100{\sim}600MU/min$)은 300 Mu/min을 기준으로 했을 때 모든 선량률 범위에서 0.4% 미만의 선량변화를 보였다. 또한, 물팬톰에서 0.1 cc 지두형 전리함으로 측정한 출력계수와 폴리스틸렌 팬톰에서 MatriXX로 측정한 출력계수를 비교하였다. 이 실험의 결과, $3{\times}3{\sim}24{\times}24cm^2$ 범위에서 0.5% 미만의 일치를 나타내었다. 단기 출력재현성 확인을 위하여 15분 간격으로 6회 측정한 결과, 0.5% 내의 차이를 보였다. 동적쐐기와 세기변조 방사선 조사면의 일치성 실험에서도 치료계획장치의 계산값과 필름측정값이 비교적 잘 일치함을 알 수 있었다. 본 연구를 통해 MatriXX의 물리적인 특성을 분석하였으며 세기변조방사선치료의 품질관리를 위한 유용성을 확인하였다. A commercial ion chamber matrix was examined the characteristics and its performance for radiotherapy qualify assurance. The device was the I'mRT 2D-MatriXX (Scanditronix-Wellhofer, Schwarzenbruck, Germany). The 2D-MatriXX device consists of a 1020 vented ion chamber array, arranged in $24{\times}24cm^2$ matrix. Each ion chamber has a volume of $0.08cm^3$, spacing of 0.762 cm and minimum sampling time of 20 ms. For the investigation of the characteristics, dose linearity, output factor, short-term reproducibility and dose rate dependency were tested. In the testing of dose linearity. It has shown a good signal linearity within 1% in the range of $1{\sim}800$cGy. Dose rate dependency was found to be lower than 0.4% (Range: 100-600 Mu/min) relative to a dose rate of 300 Mu/min as a reference. Output factors matched very well within 0.5% compared with commissioned beam data using a ionization chamber (CC01, Scanditronix-Wellhofer, Schwarzenbruck, Germany) in the range of field sizes $3{\times}3{\sim}24{\times}24cm^2$. Short-term reproducibility (6 times with a interval of 15 minute) was also shown a good agreement within 0.5%, when the temperature and the pressure were corrected by each time of measurement. in addition, we compared enhanced dynamic wedge (EDW, Varian, Palo Alto, USA) profiles from calculated values in the radiation planning system with those from measurements of the MatriXX. Furthermore, anon-uniform IMRT dose fluence was tested. All the comparison studies have shown good agreements. In this study, the MatriXX was evaluated as a reliable dosimeter, and it could be used as a simplistic and convenient tool for radiotherapy qualify assurance.

      • KCI등재후보

        MR Polishing을 이용한 커버글라스의 굽힘강도 향상에 관한 연구

        이정우,김지훈,임동욱,하석재,Lee, Jeong-woo,Kim, Ji-Hun,Lim, Dong-Wook,Ha, Seok-Jae 한국금형공학회 2022 한국금형공학회지 Vol.16 No.1

        Coverglass of electronic equipments is thinner and slimmer, so the glass must have good bending strength. In these days, the polishing edge of glass is used by solid tool like grinding wheel. But solid tool leave micro crack or edge chipping in edge of glass. MR polishing is an optimal method by polishing edge of glass. MR polishing is used MR fluid that is a liquid tool. MR polishing doesn't leave tool path or residual stress, micro crack and edge chipping unlike grinding wheel polishing. In this paper, the results of grinding and MR polishing were compared and analyzed to improve bending strength by minimizing edge chipping of cover glass. It was derived that the depth and size of cracks have a significant influence on the bending strength of the glass edge. The edges of the glass using MR grinding were analyzed to have a better surface and higher bending strength than the glass using abrasive wheel grinding. It was confirmed that MR polishing had an effect on strength improvement by effectively removing cracks in the specimen.

      • 반도체 capacitive 지문 센서 및 이미지 합성 방법

        이정우,민동진,김원찬,Lee, Jeong-Woo,Min, Dong-Jin,Kim, Won-Chan 대한전자공학회 1999 電子工學會論文誌, D Vol.d36 No.2

        본 논문에서는 저 비용, 고해상도 반도체 지문 센서칩에 대하여 논한다. 제작된 테스트 칩은 $64{\times}256$ 센싱 셀(sensing cell)로 구성되어 있으며, 칩의 크기는 $2.7mm{\times}10.8mm$이다. sensing cell 내부에서 일어나는 전하 재분포를 감지하는 새로운 방식을 이용하여 내부의 기생 캐패시턴스의 영향을 효과적으로 제거하는 방법을 제안하였다. 제안하는 방법은 센싱 셀의 감지 능력을 키우므로 센싱 셀의 크기를 줄일 수 있고, 따라서 고해상도의 이미지를 추출할 수 있다. 표준 0.6${\mu}m$ CMOS 공정을 이용하여 제작된 칩은 600dpi의 해상도를 가지는 지문 이미지를 추출한다. 제조 단가를 낮추기 위하여 지문의 부분 이미지들로부터 전체 지문 이미지를 얻어내는 이미지 합성 방법의 가능성과 문제점에 대해서도 논의하였다. This paper introduces a possibility of a low-cost, high-resolution fingerprint sensor chip. The test chip is composed of $64{\times}256$ sensing cells(chip size : $2.7mm{\times}10.8mm$). A new detection circuit of charge sharing is proposed, which eliminates the influences of internal parasitic copacitances. This the reduced sensing-capacitor size enables a high resolution of 600dpi, using even conventional 0.6${\mu}m$ CMOS process. The partial fingerprint image captured therefrom are synthesized into a full fingerprint image with a image synthesis algorithm. The problems and possibilities of image synthesis technique are also analyzed and discussed.

      • KCI등재
      • 확장된 쐐기조사야에 의한 조직산란계수의 변화

        이정우,조화섭,박성렬,Lee, Jeong-Woo,Cho, Hwa-Seop,Park, Seong-Ryul 대한방사선치료학회 1998 大韓放射線治療技術學會誌 Vol.10 No.1

        In recent days, although many kinds of beam modifiers are developing and using for clinical purposes in accordance with progressing medical engineering, physical wedges are preferred to use as a beam modifier by a lot of institutions until now because of cost, complexities of dosimetry and mechanical uncertainties. According to progressing technology, available field size of wedge is more enlarger than that of old model LINAC. Because field size dependence of wedged fields increases in new model LINAC, we was trying to know that how much different PSFs are in enlarged wedged fields compared with open fields. In small or middle size of fields($4{\times}4{\sim}15{\times}15cm$), there are only a few percents of PSF variation between open and wedged fields. But there are $2{\sim}8\%\;variations\;in\;relatively\;large\;fields(20{\times}20{\sim}30{\times}40cm)$.

      • KCI등재

        과다 유두(Supernumerary Nipple) 2례

        이정우,양정덕,이정훈,최강영,김귀락,정호윤,조병채,Lee, Jeong-Woo,Yang, Jung-Dug,Lee, Jung-Hun,Choi, Kang-Young,Kim, Gui-Rak,Chung, Ho-Yun,Cho, Byung-Chae 대한성형외과학회 2010 Archives of Plastic Surgery Vol.37 No.5

        Purpose: Supernumerary nipple or polythelia is one of the developmental anomalies occurring at the embryonic stage and this anomaly usually arises from the milk line. While this atypical feature is determined during early developmental stage, it may not come out obviously or become troublesome until puberty or lactation. Moreover, sometimes it is confused with a pigmented nevus. Methods: Case 1, a 18-year-old woman with intramammary supernumerary breast consisted of another nipple with middle sized areola on the right lower breast was admitted for a $2.8{\times}3.1\;cm$-sized mass on the right breast which was starting appeared 1 year earlier. The preliminary cytological examination of the material obtained by needle aspiration biopsy from the mass was revealed by fibroadenoma with no malignant change. The patient had the surgical excision of the mass and accessory breast. Case 2, a 16 year-old woman admitted for intra-areolar polythelia of the left breast, even she doesn't have any family history of polythelia. Since she wanted surgical correction of her atypical nipple for aesthetic and psychological reasons, we reconstructed the areola using transposition flaps in an S-plasty design. Results: Case 1, the excised supernumerary nipple showed following histological features. In the superficial layer, an acanthotic and hyperpigmented epithelium with elongated rete ridges was found. In the dermis, there were follicles with hairs surrounded by hypertrophic sebaceous glands. In the deepest portion, abundant secretory glomerules and excretory ducts of apocrine gland type were observed. Case 2, follow-up visits 3 months after the procedure showed a satisfactory result with good shape and projection of the nipple. Conclusion: We report two cases of aberrant mammary tissue who underwent surgical correction, including complete breast (with nipple, areola, and glandular tissue) and intra-areolar polythelia according to the Kajava's classification, and the results were satisfactory.

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