MgCl₂溶液內에서 STS 304 HP Stainless Steel 熔接部의 破壞擧動에 對한 硏究

金永奭,丁太權,朴昌彦,洪錫柱,梁仁榮,金基玉,朴煥奎,李茂錫,曺圭宰,鄭在康 조선대학교 생산기술연구소 1983 生産技術硏究 Vol.1983 No.-

This paper is based on an experiment analysing the stress corrosion cracking behaviour of welding specimens compared to that of non-welding specimens of STS 304 HP stainless steel in corrosion solution. As a corrosion condition, stainless steel has been known to be the most fragile in a solution of 42% MgCl₂heated to the boiling point, therefore the experiment was carried out in this condition. The experiment was carried out with argon gas TIG welding specimens and non-welding ones made of stainless steel plates, thickness 2mm, by tensile force. At this time, the tensile force was taken to be the value of the yield strength of the tensile test specimens divided by the safety factor of 3.0 to 3.5, 4.0, 4.5, and 5.0. In this paper, the relations between Time of Initial Crack, Time of Failure, Time of Final Fracture and Crack Propagation Length were investigated and then plotted. Furthermore, the relations between Stress Intensity Factor K proposed by Irwin and the Time of Initial Crack, the Time of Failure, the Time of Final Fracture were calculated and plotted. At the last, all the relations plotted were expressed to normal equations by computer, and the equations were used to analyse the data obtained in the experiment. The conclusions obtained in this study are as follows: 1. Welding materials, compared with non-welding ones, as the Time of Initial Crack, the Time of Failure, and the Time of Final Fracture were generally very fast, appeared to be a phenomenon of unstable brittleness fracture. 2. Non-welding materials, compared with welding ones, as the safety factor was larger or the working stress was smaller, appeared to be a phenomenon that the longer had had greater durability. Therefor, welding materials must be considered enough to be used in heate affected and stress corrosion atmosphere. 3. The normal equations of the Time of Initial Crack and the variation rate to the same Stress Intensity Factor K are as follows: (A) Non-welding T =259702.4-5451.2 K+28.386 K² T = -5451.2+28.386 K (B) Welding T= -332.693+28.043 K-0.211 K² T' =28.043-0.211 K here, T; Time of Initial Crack, T'; Variation Rate of Time of Initial Crack to Stress Intensity Factor K, K ; Stress Intensity Factor.

Elastic Open Activator를 이용한 Ⅱ급 부정 교합의 치료효과

정규림,박영국,이현경 대한치과교정학회 1995 대한치과교정학회지 Vol.25 No.5

Elastic Open Activator(E.O.A)는 myodynamic activator의 일종으로서 장치의 아크릴 부위의 대폭적인 크기 감소로 환자가 거부감 없이 장시간 착용할 수 있는 장점을 가지며, 구강내에서 매우 느슨하게 장착되므로써 보다 적극적인 근기능 자극 효과를 나타내고, 구강 내외의 제 기능시 발휘되는 생리적인 힘을 효율적으로 치조골 및 악관절부에 전달시킨다. 특히 기능모체(functional matrix)를 효과적으로 차단하는 동시에 능동적으로 자극함으로써 많은 부정교함 증례에서 비발치에 의한 교정치료의 성공률을 높이는 것으로 사료된다. 이 연구는 혼합치열기 및 초기 영구치열기의 Ⅱ급 부정교합 환자에게 사용된 E.O.A의 치료효과를 구명하기 위하여 시행되었으며 경희의료원 교정과에 내원하여 Ⅱ급 1류 및 2류 부정교합으로 진단되었던 각각 9명과 5명의 치료 전후 cephalogram 및 석고모형을 비교분석한 후 결과를 평가하여 다음과 같은 결론을 얻었다. 1. 상악골은 두 군 모두에서 정상적인 성장 양태를 유지하였다. 2. 하악골은 두 군 모두에서 크게 전하방 성장되었다. 3. 상악 전치는 Ⅱ급 1류 부정교합자에서는 설측, Ⅱ급 2류 부정교합자에서는 순측 경사되었고 두 군 모두에서 상하악 전치부 치조골 수직 성장이 억제되었다. 4. 하악 전치는 두 군 모두에서 약간 순측 경사되었다. 5. 두 군 모두에서 상, 하악 치궁의 확장이 일어났으며 Ⅱ급 2류 부정교합자에서 가용 공극의 길이가 증가되었다. The elastic open activator is one of the modified myodynamic activator. The reduced size of the appliance mass motivates the patients' comfort and longer time of wearing. Its peculiarities in loose fitting and the lack of appliance stabilization in the mouth draws the tongue and the surrounding functional matrices on close interaction with the appliance, consigns the physiologic exertion to target structures, and eventually makes it feasible to the inland of non-extraction treatment. In the context of the sagittal malocclusion, the orthodontic trench is dependent upon the growth of basal structure aimed, therefore, it is contemplated to grabble the effects of Elastic Open Activator upon the class Ⅱ malocclusion of growing child retrospectively. The cephalometric headfilms and study models of nine class Ⅱ malocclusion of growing child retrospectively. The cephalometric headfilms and study models of class Ⅱ division 1 and five division 2 patients were evaluated and analyzed, and the following observations were drawn ; 1. The maxilla maintained a normal growth pattern in both groups. 2. The mandible grew anteroinferiorly in both groups. 3. The upper incisors tipped ligually in Class Ⅱ division 1 and tipped labially in Class Ⅱ division 2 and anterior vertical alveolar growth was interrupted in both groups. 4. The lower incisors tipped labially. 5. There was an arch expansion in both groups and increase of available space in Class Ⅱ division 2

TMS320F240을 이용한 PWM 인버터 유도전동기 구동 시스템의 전도노이즈 저감을 위한 스위칭 기법

朴奎炫,金利勳,元忠淵,金奎植,崔世琓,咸年根 성균관대학교 2003 학술회의지원논문목록집 Vol.2003 No.-

PWM 인버터에 의해 구동되는 유도전동기에 발생되는 고주파 커먼 모드 전압은 전도성 EMI, 전동기 접지전류, 베어링 전류 및 다른 원치 않는 결과의 주원인이 된다. 인버터 제어의 무효벡터 스위칭 상태는 나머지 유효벡터 스위칭 상태에 비교하여 큰 커먼 모드 전압을 일으킨다. 그러므로 이 논문은 커먼 모드 전압을 완화하는 스위칭기법을 다룬다. 즉 정현파 PWM기법을 기본으로 한 커먼 모드 전압 제거방법을 제안하였다. PWM 신호는 각각의 정현파 기준신호와 120˚위상차가 나는 3개의 캐리어 파형과 비교하여 발생된다. 시뮬레이션과 실험적결과는 제안된 PWM 기법에서 커먼 모드 전압이 종래의 PWM 기법보다 약 66% 더 저감됨을 보였다. High frequency common mode voltage produced by PWM inverter fed induction motor is a major cause of conducted EMI. creation motor ground currents, bearing currents and other hamful products. The zero switching states of inverter control invoke large in comparison with the non-zero switching state of inverter control. We proposed a common mode voltage reduction method based on sinusoidal PWM technique. PWM signal are generated by comparing respective sinusoidal reference signal with three triangular carrier wave displaced of 120˚. Simulation and experimental result show that common mode voltages in the propsed PWM technique are reduced by approximate 66% more than conventional PWM technique.

支配關係를 利用한 順位化法

박상규,정규련 한국경영과학회 1992 韓國經營科學會誌 Vol.17 No.2

In this paper fuzzy ranking method using dominance relation is suggested. This method is compared to the existing fuzzy number comparing methods. All ten methods with the suggested method are evaluated using six examples based on four criteria.

"지황 1호"를 이용한 숙지황 제조기술 연구

박남규,김선림,허한순,박충현 한국국제농업개발학회 2002 韓國國際農業開發學會誌 Vol.14 No.1

재래종 지황과 신육성품종 지황 1호를 이용하여 절단 및 원형으로 숙지황을 제조한 결과는 다음과 같다. 1. 가압에 의한 숙지황 제조시간이 재래종은 254∼264시간, 제품수율이 71.42∼71.48%였고, 지황 1호는 제조시간이 260∼276시간 소요되었고, 수율은 71.50∼71.51%였으며 중량은 감소하는 경향이었다. 2. 상압에 의한 숙지황 제조에서도 가압에 의한 제조와 비슷한 경향을 보였다. 3. 가압과 상압에 의한 숙지황 제조 후 유리당 조성은 재래종, 지황 1호 전처리구에 63∼65% 이상이 fructose였으며, 30% 이상이 glucose였고, sucrose, maltose가 함유되었다. 4. 가압 및 상압에 의한 숙지황 제조시 catalpol 함량 변화는 종자회수가 많아질수록 caltalpol 함량이 낮아지는 경향이었으나 완전히 없어지지는 않았다. 5. 숙지황 제조 후 포장재별로 포장하여 상온에 저장한 결과 제품에 곰팡이 발생이 없어 저장에 문제가 없었다. New processing method for R. Radix preparata was developed by using the landrace variety as a control and "Jiwhang 1" (Rehmannia glutinosa Liboschitiz). Sliced Rehmanna glutionsa Liboschitiz was steam heated by normal and high pressure conditions for the round-shaped R. Radix preparata processing. About 254 to 264 hours were required for the processing of domestic variety, and about 260 to 280 hours were required for "Jiwhang 1", but their yields were ranged about 71.42∼71.6%. Fructose and glucose were major free sugar of R. Radix preparata, and their composition rates were 63∼65% and 30%, respectively, but sucrose and maltose were traced only small amount. The Catalpol content was decreased as increasing the frequencies of steam heating repetion. But the catalpol was not completely removed. After processing, R. Radix preparata packed with paper-bag or PE-bag, and storaged at common temperature was keeping a best quality.

드라이브 일렉트로닉스의 동향과 전망

鄭東和,朴奎南 순천대학교 공업기술연구소 1993 工業技術硏究所論文集 Vol.7 No.-

Drive electronics has been defined as multi-disciplinary technology that encompasses power semiconductor devices, converter circuits, electrical machines, signal electronics, control theory, microcomputers, VLSI circuits and CAD techniques. Although drive electronics engineers polarized in a narrow segment of the spectrum in this area should have more or less experience in all the above component disciplines. This is indeed a challenge since most these disciplines are going through fast technological evolution. This paper describes technology trend and view with AC drive of drive electronics.

EKF를 이용한 유도전동기의 속도센서리스 백터제어

鄭東和,朴奎南 순천대학교 공업기술연구소 1994 工業技術硏究所論文集 Vol.8 No.-

In field oriented control of induction motors, speed sensor is required which reduces the sturdiness of drive system and together with the expenditure of hardware for faultless transmission and processing of sensor signals it causes considerable expenses. These expensive sensor can be replaced by speed sensorless concept. And for good control, the knowledge of the rotor flux component or the rotor resistance are needs. This paper is based on a extended kalman filter(EKF) that estimates the state variables that are required for the control by only measuring the line voltage and current of the machine The rotor resistance and speed estimated by the EKF shows satisfactory agreement with actual values with simulation.

다양한 표피 종양에서 Matrix Metalloproteinase-2와 Matrix Metalloproteinase-9 발현에 관한 면역조직화학적 연구

박홍표,최규철,정병수 조선대학교 부설 의학연구소 2002 The Medical Journal of Chosun University Vol.27 No.1

Background and Objectives: Degradation of basement membranes and extracelluar matrix is a essential step in tumor cell migration, invasion and metastasis formation. Two types of Matrix metalloproteinases (MMPs), MMP-2 and MMP-9 are active in the digestion of type Ⅳ collagen, the main constituent of the basement membrane. Based on this background, we investigated the expression patterns of Type Ⅳ collagenase (MMP-2 and MMP-9) in squamous cell carcinoma, adenoid (acantholytic) squamous cell carcimoma, and its precancerous conditions, actinic keratosis and Bowen's disease by immunohistochemical technique. Materials and Methods: Formalin-fixed and paraffin-embedded tissues from 5 actinic keratosis, 5 Bowen's diseases, 5 adenoid squamous cell carcinoma, and 5 squamous cell carcinoma were immunolabelled with monoclonal antibodies directed against MMP-2 and MMP-9. Result: For MMP-2, actinic keratosis, Bowen's disease, adenoid squamous cell carcinoma, and squamous cell carcinoma was expressed to relative low level in tumor cells. Bowen's disease showed a negative staining for MMP-9, but in microinvasive area of actinic keratosis and adenoid lining cells of adenoid squamous cell carcinoma was a positive staining or MMP-9. In Bowen's disease, squamous cell carcinoma, and adenoid squamous cell carcinoma, dyskeratotic cells and acantholytic cells were stained for MMP-2 but for MMP-9, only in adenoid squamous cell carcinoma. Conclusion: This finding suggested that MMP-9 may be related to tumor invasion to surrounding stroma and that MMP-2 and MMP-9 may be involves in the apoptotic process of the tumor cells.

외과계 감염증에 대한 Sulperazon(Sulbactam/cefoperazone) 및 Cefoperazone의 임상효과 비교연구

박규주,노동영,김상준,권오중,정중기,홍인규 대한화학요법학회 1990 대한화학요법학회지 Vol.8 No.2

Despite recent advances in development of antibiotics and antiseptic techniques, infection still remains to be one of the major problems in the surgical field. Due to development of bacterial resistance to commonly used antibiotics, there is always a need to develop a new antimicrobial agent which would overcome such resistance. Sulperazon (Sulbactam/Cefoperazone) is a combination drug of potent β-lactamase inhigitor, sulbactam, and cefoperazone which has broad antibacterial spectrum, which was developed to combat against β-lactamase producing microorganisms. In an effort to evaluate the efficacy and safety of sulperazone, we have randomly divided 40 patients (12 with perforated appendicitis, 10 with peritionitis, 6 with GB empyema, 6 with periproctal abscess, 3 with wound infection, 1 liver abscess, 1 pancreatic abscess, and 1 acute cholangitis) into 2 groups (20 patients in each group). One group received daily dose of 2 to 3 grams of sulperazon and the other group received daily dose of 2 to 3 grams of cefoperazone. Following results were obtained : 1. Clinical effect of sulperazon was cure in 16 patients (80%), improvement in 3 patients (15%), compaired to cure in 14 patients (70%), improvement in 4 patients (20%) for the cefoperazone group. 2. Using disc diffusion method, sulperazon was sensitive to all of the isolated microorganisms except β-hemolytic streptococci, which was moderately sensitive. Cefoperazone was sensitive to only E. coli, Pseudomonas aeruginosa and Serratia. 3. Microbiological effect of sulperazon was eradication of offending microorganisms in 16 patients (80%), compared to 14 patients (70%) in Cefoperazone group. 4. Overall clinical efficacy of sulperazon was 95%, compared to 80% for cefoperazone. 5. Adverse effects due to sulperazon was nausea and diarrhea which occurred in 1 patient respectively. 2 patients receiving cefoperazone experienced diarrhea. It can be concluded that sulperazon is a safe and effective antibiotic agent which can be used in surgical infection patients.

Agrobacterium 이용한 형질전환 시 배추 풍종간 callus 발생율 및 식물체 재분화율 비교

박태성,정규환 中央大學校 遺傳工學硏究所 2002 遺傳工學硏究論集 Vol.15 No.1

An effective condition for callus formation or shoot and root regeneration from Chinese cabbage (Brassica campestris ssp. pekinensis) 'Samjin' and 'Seoul' using a-NAA, 2,4-D and BAP during the Agrobacterium mediated transformation were investigated. The most suitable cotyledon and hypocotyl of Chinese cabbage for transformation were obtained 4 day after germination. Among various combinations of a-NAA, 2,4-D and BAP tested, the combination of 1 mg/L 2,4-D and 0.1, 1 mg/L BAP showed the highest rate of callus formation. In the Agrobacterium mediated transformation experiment, however, the combination of 1 mg/L a-NAA and 4mg/L BAP showed more effective results on shoot and root regeneration. The callus formation rate from Chinese cabbage 'Seoul' showed 2.4∼10 times higher than Chinese cabbage 'Samjin'. The root and shoot induction rate from Chinese cabbage 'Seoul' also showed 6∼12 times higher than Chinese cabbage 'Samjin'.