이중조직을 가지는 Ti-6Al-4V 합금의 동적 변형특성에 미치는 템퍼드 마르텐사이트 분율의 영향

이동근,이유환,이종수,이성학 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.6

The effects of volume fraction of tempered martensite on quasi-static tensile and dynamic deformation properties of Ti-6Al-4V alloy with bimodal microstructure were investigated in this study. Five microstructures with various tempered martensite volume fractions were obtained by varying heat-treatment temperatures and times. Dynamic torsional tests were conducted on them by using a torsional Kolsky bar. The test data were analyzed in relation to microstructures, tensile properties, and adiabatic shear band formation. Under a dynamic loading condition, maximum shear stress increased with increasing tempered martensite volume fraction, whereas fracture shear strain decreased. Observation of the deformed area beneath the fracture surface after the dynamic torsional test indicated that a number of voids initiated mainly at a/martensite interfaces, and that the number of voids increased with increasing martensite volume fraction. Adiabatic shear bands of 6-10 lam in width were formed in the specimens having lower martensite volume fractions, while they were not formed in those having higher martensite volume fractions. The possibility of the adiabatic shear band formation was explained by concepts of absorbed deformation energy and void initiation. (Received April 7, 2004)

원위기저 비복동맥 피판술

이동걸,이동훈,이정형,조병채,백봉수 大韓成形外科學會 1999 Archives of Plastic Surgery Vol.26 No.3

Reconstruction of soft tissue defect with exposure of the tendons and bone in the lower third of the leg and the heel represents a challenge to plastic surgeons. The sural artery flap is a fasciocutaneous flap supplied by the sural artery that accompanies the sural nerve and connects with a septocutaneous perforator of the peroneal artery via a suprafascial network of vessels. For the coverage of soft tissue defects, we operated on 10 patients using a distally-based sural artery flap. The sites of the soft tissue defect were the lower third of the leg in 7 cases and the heel in 3 cases. The size of flap varied from 3.5x4cm to 12x18cm. Nine of 10 flaps survived completely. One flap in which the sural nerve was preserved showed partial necrosis but healed spontaneously. Two flaps showed slightly venous congestion which disappeared after a few days. The advantages of the sural flap are a reliable blood supply, easy and quick elevation of the flap, preservation of the major artery and minimal donor site morbidity. The disadvantage of the flap is hypoesthesia at the lateral part of the foot. In conclusion, the distally-based sural artery flap can be used safely for soft tissues coverage in the lower third of the leg and the heel.

Ti-6Al-4V 합금의 동적변형특성과 탄도충격성능 : 1. 초고속 폭발충격 특성 1. Ultra-high-speed Exploding Properties

이유환,이동근,이성학,이종수,최준홍,허선무 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.10

The effects of microstructural morphology on ultra-high-speed exploding properties of Ti-6Al-4V alloy were investigated in this study. Exploding bridge wire (EBW) test was conducted on equiaxed and bimodal microstructures, which were processed by different heat treatments. From the test, moving velocity of free surface vs time profiles were obtained to measure strength at Hugoniot elastic limit (HEL) and spall strength and to subsequently predict ballistic mass efficiency. The EBW results indicated that impact resistance of the bimodal microstructure was better than that of the equiaxed microstructure when the measured strength at HEL and spall strength were considered. It was also learned from the observation of fractured EBW specimens that fracture occurred by the initiation and propagation of long cracks in the equiaxed microstructure, whereas a number of microcracks were formed and connected each other in a zig-zag pattern to reduce the driving force for crack propagation in the bimodal microstructure. Since the EBW test helped experimentally estimate ultra-high-speed deformation and fracture behavior, it could be effectively used for the prediction of ballistic impact performance.

플라즈마 표지소자의 제작

이상윤,라병욱,박동수,황인헌,이덕동,신영남,박성배,이동욱,박용석,박형근,손상호,권태근,채경락,정경득 慶北大學校 自然科學大學 1986 自然科學論文集 Vol.4 No.-

An Ac-type Plasma Display Panel (PDP) operating with Ne-Ar(0.1%) Penning mixture gas is fabicated. The characterics of the panel with electrodes covered with thin and thick dielectric layers are studied. The brightness of the Neon-orange light emitted by the panel measured as function of applied voltage and frequency. As an application, a graphic display system equipped with PDP showing still and moving pictures is made.

한국인에게서 그레이브스병 약물치료의 적정기간

이형숙,이동훈,정희선,이종우,김정은,신승수,정윤석,이관우,김현만 대한내분비학회 2003 Endocrinology and metabolism Vol.18 No.1

연구배경: 그레이브스병의 치료에는 항갑상선제, 수술 및 방사성 요오드법이 선택되어 사용되고 있다. 이중 항갑상선제는 가장 많이 선호되고 있으나 낮은 관해율과 높은 재발율로 장기간 치료기간이 요구된다. 저자들은 그레이브스병 환자에게서, 선택되는 치료법의 선호도와 각 치료법의 관해율을 조사하고자 본 연구를 시행하였다. 또한 본 연구에서는 항갑선제 치료의 적정기간을 평가하고자 하였다. 방법: 아주대학교병원에 내원한 환자 중 1년 이상 추적관찰이 가능한 205명의 그레이브스병 환자를 대상으로 조사하였다. 항갑상제군, 수술군 및 방사성 요오드군은 각각 170명, 29명 그리고 6명이었다. ROC curve를 이용하여 약물치료의 예후예측인자를 분석하였다. 결과: 1) 그레이브스병 환자의 치료 방법의 선택은 항갑상선제군, 수술군 및 방사성 요오드군 각각 170명(83.0%), 29명(14.1%) 그리고 6명(2.9%)으로 항갑상선제 치료가 가장 선호되었다. 2) 그레이브스병의 관해율은 항갑상선제군, 수술군 및 방사성 요오드군에서 각각 60.0%(102/170명), 96.5%(28/29명) 그리고 83.0%(5/6명)으로 수술군이 가장 높았다. 3) ROC curve의 AUC는 치료기간과 진단시 TBII가 각각 0.709 및 0.648이었고 적절한 약물투여 추적 관찰기간은 26개월이었다. 결론: 그레이브스병의 일차 치료법으로는 항갑상선제가 선호되고 있으나 수술 및 방사성 요오드 치료군에 비해 상대적으로 낮은 관해율을 보였다. 따라서 항갑상선제 치료로 26개월 이상 관해가 되지 않을 경우에는 치료 방법의 변경을 고려하는 것이 관해율을 높이는데 도움이 될 것으로 생각된다. Background: Graves' disease in an organ specific autoimmune disease. Three kinds of therapeutic modalities (antithyroid drugs, ablation with radioactive iodine and subtotal thyroidectomy) are frequently performed for the management of this disease. The most popular therapeutic policy for the disease in Korea is antithyroid treatment. We analysed and compared the remission rates of all three modalities for Graves' disease, and evaluated the antithyroid modality to determine the correct duration of treatment. Subjects & Methods : The medical records of 205 patients with Graves' disease were reviewed. For the evaluation of the antithyroid modality medical treatment, antithyroid drugs were administered for more than 1 year. The prognostic factors associated with remission were analysed by means of an ROC curve. Results: 1) Of the 205 patients, proportions that received medical therapy, subtotal thyroidectomy and radioiodine therapy were 83.0, 14.1 and 2.9%, respectively. 2) The remission rates of the medical therapy, surgery and radioiodine therapy were 60.0, 96.5 and 83.0%, respectively. 3) The remission rate of the medical therapy was associated with the duration of medication and TBII activity. The determined proper duration for the antithyroid treatment was 26 months from the ROC curve analysis. Conclusion: The above results suggest that the proper duration of antithyroid treatment for Graves' disease is 26 months, after which time the subtotal thyroidectomy or radioiodine therapy should be considered if the disease has not remitted (J Kor Soc Endocrinol 18:24∼31, 2003).

Analysis of Insulation Diagnosis for Generator‑Motor Stator Winding in Pumped Storage Power Plant

Soo‑Hoh Lee,Tae‑Sik Kong,Hee‑Dong Kim 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.3

In this study, insulation diagnostic tests were conducted on pumped storage power plant (PSPP) generator-motor stator bars with artifcially simulated defects in order to improve solutions to perform preventive maintenance and track insulation diagnostic data for generator-motors by proving the efectiveness of insulation indices. Moreover, ozone (O3) concentration was estimated in order to relate it to partial discharge (PD) in laboratory to ensure the efectiveness of ozone as another index for insulation deterioration. By performing an ofine PD test and ultraviolet (UV) observation on one of the generator-motors during overhaul, and an ozone concentration measurement for the identical machine after the overhaul, it was concluded that ozone estimation could be a powerful index for insulation diagnosis under actual operational conditions. It was further developed that ozone measurement is useful to detect not only discharges in slots as mentioned in some studies but also discharges at the end-winding as proven in this study. The fndings of this study are expected to contribute to more reliable maintenance of generator-motors in PSPPs by achieving elaborate insulation diagnosis via multiple diagnostic indices.

Lightweight Printed Dipole Antenna Array With 3×2 Beamforming Network for Wide UAV Communication Coverage

Dong‑Geun Seo,Jeong‑Soo Park,Gun ‑Ki Lee,Wang‑Sang Lee 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4

In this paper, a lightweight printed dipole antenna array with 3×2 beamforming network for wide unmanned aerial vehicle (UAV) communication coverage is presented. The proposed antenna consists of an upper substrate, a lower substrate, and two supports with a microstrip feeding. The upper substrate has a two-element printed dipole antenna array, and the lower substrate includes a beamforming feeding circuit and a ground plane as a refector of the proposed antenna array for gain improvement. For wide beam coverage, the proposed feeding network consists of three RF switches, one Wilkinson power divider, and one 90° hybrid coupler, and generates the wide beam using one broadside beam and two end-fre beams. Measured impedance bandwidth, peak gain, and half-power beamwidth (HPBW) of the proposed array operated from 5.03 to 5.15 GHz are approximately 2 GHz, 4.3 dBi, and 155°, respectively.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

DTMF 신호를 이용한 전자 보안 시스템

이병수,이순흠,박동규,이동원,이선휘,황유동 순천향대학교 부설 산업기술연구소 1999 순천향 산업기술연구소논문집 Vol.5 No.2

we have developed cost-effective effectronic security system. The system is superior to the day-time alert system which is currently used for banks in Choongchung Province. The system can monitor 512 banks and inform the police of emergency state and its related informations. The developed svstem is under field test at a police station in Choongchung Province.

Ti-6Al-4V 합금의 동적변형특성과 탄도충격성능 : 2. 동적비틀림 특성과 탄도충격성능 2. Dynamic Torsional Properties and Ballistic Performance

이동근,이유환,이성학,이종수,이충열,허선무 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.10

The effects of microstructural morphology on dynamic deformation and fracture behavior and ballistic performance of a Ti-6Al-4V alloy were investigated in this study. Ballistic impact tests were conducted on equiaxed and bimodal microstructures, which were processed by different heat treatments, and then the test data were analyzed in relation to microstructures, tensile properties, and dynamic torsional test data. In the impacted region of the equiaxed microstructure, a number of adiabatic shear bands and cracks were observed to be formed along plastic flow lines, and delamination occurred because of cracking along the plastic flow lines or shear bands. In the case of the bimodal microstructure, shear bands were found in limited area near the impacted region without occurring delamination, and their number was fewer than that of the equiaxed microstructure. Thus, ballistic performance of the bimodal microstructure was better than that of the equiaxed microstructure. The ballistic performance of the two microstructures was also discussed by comparing the possibility of adiabatic shear band formation obtained from dynamic torsional test data.