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불연속 전류모드에서의 다상 교호 강압컨버터의 정상상태 해석 및 모델링
장성동(Sung-Dong Chang),장은승(Eun-Sung Jang),정세교(Se-Kyo Chung),신휘범(Hwi-Boem Shin),이현우(Hyun-Woo Lee) 한국조명·전기설비학회 2004 한국조명·전기설비학회 학술대회논문집 Vol.2004 No.5월
A multi-phase interleaved buck converter is used to reduce current ripples and filter size of a power supply. This paper addresses the modelling and steady-state analysis of the multi-phase interleaved buck converter operated in discontinuous inductor current mode. The model is derived using an averaging technique in steady state. The do voltage ratio and the range of the discontinuous inductor current mode(DICM) and the continuous output current mode(COCM) are derived from the averaged state-space model. In addition, the efficiency is investigated according to the number of phase.
배터리차 추진제어를 위한 병렬 MOSFET의 도통전압을 이용한 전류파형 검출
장성동(Sung-Dong Chang),김성중(Sung- Joong Kim),정재호(Jae-Ho Chung),신휘범(Hwi-Beom Shin) 전력전자학회 1999 전력전자학술대회 논문집 Vol.1999 No.7
In this paper, an algorithm of reconstructing the armature current of the battery car is presented by using MOSFET's on-voltage of the dc chopper and a corresponding circuit is developed with the low-cost analog multiplexer. For driving comfort, the armature current of the motor or the traction force should be properly controlled when the car changes the direction and is accelerated or decelerated and climbs up or down the hill. Therefore, an information of the current IS needed for the traction control. The proposed reconstruction algorithm IS experimentally verified.
박지현,장성동,이세엽,Ji Hyun Park,M,D,Sung Dong Chang,M,D,Se Youp Lee,M,D 대한안과학회 2008 대한안과학회지 Vol.49 No.1
`Purpose: There have been no reports of optic nerve injuries caused by gunshot in Korea. We describe such an injury and report the treatment outcomes. Case summary: A patient visited our hospital complaining of visual disturbance after her right zygomatic bone had been shot with an airgun during a suicide attempt in September 2006. A visual acuity test, pupillary light reflex test, fundus examination, skull X-ray, and computed tomography (CT) were performed. At the initial examination, the right eye had no light perception. The pupillary light reflex test revealed an afferent pupillary defect, and the fundus examination showed central retinal artery occlusion. The skull X-ray and computed tomography revealed a fracture of the right medial and lateral orbital walls as well as a partial injury to the medial rectus muscle. In addition, right retrobulbar hemorrhage and metallic foreign bodies were observed in the right orbit. Under general anesthesia, disinsertion of the superior and lateral rectus muscles was performed, and the metallic foreign bodies in the right orbit were removed. The surgical incision was then closed. A Krimsky prism test performed 7 days after surgery revealed an approximately 15 prism diopters of exodeviation of the right eye. Conclusions: We report a case of optic nerve injury caused by a gunshot.`
초심자 안과 전문의 10명에 의해 시행된 수정체유화술 중 발생한 후낭파열의 임상양상
전종화,장성동,Jong Hwa Jun,MD,Sung Dong Chang,MD,PhD 대한안과학회 2014 대한안과학회지 Vol.55 No.5
Purpose: To report the related factors of posterior capsule rupture and the difference of postoperative visual prognosis after phacoemulsification by analyzing clinical features of the surgery performed by ten novice ophthalmologists. Methods: We retrospectively evaluated electronic medical records of 326 patients (412 phacoemulsification cases) who underwent surgery by novice ophthalmologists certified by the Board of Ophthalmology after a resident training program. Results: The number of cataract surgeries performed by each surgeon within the ophthalmology fellowship period (6 months - 2 years) ranged from 16 to 75 eyes, and perioperative posterior capsule ruptures occurred in 64 of 412 eyes (15.5%). Factors such as age, sex, laterality, axial length and clinical courses were not related to the rate of posterior capsule rupture. Nucleosclerosis was significantly related to the posterior capsule rupture rate and was especially higher in the group with a grade higher than five compared to that in the groups with a grade less than 5 based on the Lens Opacities Classification System III (<em>p</em> = 0.033). Factors of surgeon's subspecialty, nucleofractis method, and period between residency and the fellowship were not related to the posterior capsule rupture rate, except when considering anesthetic methods. The posterior capsule rupture rate was less frequent in the retrobulbar surgery group than the topical surgery group (<em>p</em> = 0.046). Postoperative visual outcomes were significantly different at postoperative day one and one month (<em>p</em> = 0.023, 0.022, respectively) but not at postoperative two months (<em>p</em> = 0.059). Conclusions: Phacoemulsifications performed by novice ophthalmologists showed a statistically significant difference in posterior capsule rupture rate between nucleosclerosis and anesthesia groups. Postoperative visual outcome differed at postoperative day one and one month but not after two months postoperatively. J Korean Ophthalmol Soc 2014;55(5):679-685
조윤근,장성동,김유철,이세엽,Yun-Keun Cho,Sung-Dong Chang,Yu-Choel Kim Se-Youp Lee 대한안과학회 2005 대한안과학회지 Vol.46 No.10
Purpose: Here, we report a case of an infant with fetal alcohol syndrome with esotropia who was born to a mother who consumed a large quantity of alcohol during her pregnancy. Methods: A 1-year-old female infant visited our hospital for the main symptom of the esodeviation of the eye. The medical history of the mother and the delivery history were reviewed, and a physical examination and ophthalmic examination of the infant were performed. Results: At the first examination, the patient was 15 months old, her mass was 5,600 grams, her height was 70 cm, her head circumference was 39.5 cm, and her chest circumference was 41 cm; all the measurements were below the 3rd percentile. From the gestation age of 24 weeks, the mother consumed 1-2 bottles of sojoo every day, and the infant patient was delivered at the gestation age of 42 weeks by Cesarean section. The infant’s birth weight was 1,510 grams. Upon physical examination, her philtrum was found to be shallow, and microcephaly was detected. Upon ophthalmic examination, a refractive error +1.25 Dsph. was detected. With regard to the horizontal length of the palpebral fissure, the right and the left were 1.7 cm and 1.6 cm, respectively, which is considered short; telecanthus and esotropia were also present. Conclusions: To the best of our knowledge, this is the first reported case of fetal alcohol syndrome with accompanying esotropia.
장지혜,김유철,장성동,이세엽,김광수,Ji Hea Jang,Yu Cheol Kim,Sung Dong Chang,Se Youp Lee,Kwang Soo Kim 대한안과학회 2007 대한안과학회지 Vol.48 No.12
Purpose: We encountered a rare case of optic neuritis that developed in a sphenoid sinusitis. This case has not been reported at any of the Korean Ophthalmological Society meetings. Case summary: A 12-year-old boy with swollen optic disc was diagnosed with optic neuritis secondary to sphenoid sinusitis, through orbit MRI (magnetic resonance imaging) and paranasal sinus CT (computed tomography). We observed the recovery of visual acuity and the improvement of papilledema after treatment. In the initial examination, the BCVA (best-corrected visual acuity) of the right eye was only hand movement. Papilledema was detected by ophthalmoscopy. Orbit MRI and paranasal sinus CT were then performed, which revealed that sphenoid sinusitis had invaded the right optic nerve. Treatment included the use of antibiotics, systemic steroid therapy, and endoscopic sinus surgery. One month after treatment, the BCVA of the right eye was 1.0 and the papilla of right eye had a normal ophthalmoscopic finding. Conclusions: Sphenoid sinusitis can be a cause of optic neuritis. The treatment of optic neuritis caused by paranasal sinusitis must include antibiotics use or endoscopic sinus surgery to remove the sinus inflammation as well as high dose steroid therapy.
이동철,이중원,장성동,Dong Cheol Lee,MD,Jung Won Lee,MD,Sung Dong Chang,MD 대한안과학회 2012 대한안과학회지 Vol.53 No.2
Purpose: To report a case of fusarium keratitis treated with only moxifloxacin 0.5% ophthalmic solution (Vigamox?, Alcon Laboratories, Inc., Ft Worth, TX, USA). Case summary: A 37- year- old healthy male patient experienced a right eye injury due to grain 7 days prior to presentation at our hospital with visual disturbance and ocular pain. A 2.7 × 4.3 mm sized corneal epithelial defect with irregular featherlike midstromal infiltration was observed, and slit lamp examination revealed a dry, rough texture. Thus a smear and culture were performed. Moxifloxacin 0.5% ophthalmic solution (Vigamox?) and lubricant were applied for treatment. Three days after using the eye solution, all clinical features improved. Seven days later, Fusarium species was identified in culture. Conclusions: As standard treatment for Fusarium, the authors of the present study used an antifungal agent. Although hyphae were detected in culture, the use of only moxifloxacin 0.5% ophthalmic solution (Vigamox?) result in a satisfactory result and improvement in clinical features. J Korean Ophthalmol Soc 2012;53(2):338-341