고출력 다이오드 레이저를 이용한 SKD11 표면 열처리 특성

최성대,정선환,양승철,김잠규 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

An experimental investigation with high power diode laser system was carried out to study the effect of surface heat treatment on the SKD11. The surface heat treatment characteristics of the laser beam were evaluated using hardness tests, optical microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy(EDS). Results indicated that the Hardness were changed by beam size, focal length, feed rates. The micro grain structure was observed retained austenite grain at hardened zone and globular cementite grain at fine grain zone and base metal zone by optical microscopy. The intensive X-ray diffraction patterns of (110)-(200)-(211) was detected on the surface and the hardened surface intensity level was bigger than the unhardened surface. The intensive X-ray diffraction patterns of (110)-(200)-(211) was detected hardened surface and the hardened surface distributed plenty of carbon density than metal zone.

축산분뇨중의 암모니아성 질소 제거

진양오,최성우,김성우,김익성,신남철,박승조 동아대학교 환경문제연구소 1999 硏究報告 Vol.22 No.2

The purpose of thus study were to investigate the proper conditions of struvite formation in synthetic wastewater and then to apply these conditions to effluent of anaerobic digester of livestock wastewater The conditions of struvite formation had been studied by many researchers. But a little conditions were different among them. Especially, according to suspended solid variation in livestock wastewater was investigated by few researchers. In experiment of synthetic wastewater, the proper conditions of struvite formation were pH 105, l50rpm of mixing rate, 10 minutes of reaction time, and 20 minutes of precipitation time. At same time, the ammonia nitrogen removal rates were about 99.7%, 95.5%, and 96% of synthetic wastewater, raw wastewater, and effluent of anaerobic digester of livestock wastewater at molar ratio of 2(Mg):l(N)2(P) respectively. The larger factor of NH₄/SS constant was, the more effective the removal rate of ammonium nitrogen, SS was, but the less effective COD_(cr), and TOC was. By using XRD analysis, the most certain compound in precipitate of synthetic wastewater was struvite.

상악 제 2대구치 발치를 동반한 Ⅱ급 부정교합의 치료

문성철,장영일,양원식 대한치과교정학회 1993 대한치과교정학회지 Vol.23 No.1

The purpose of this report is to present the successful improvement of occlusal relationship and facial esthetics in class Ⅱ division 1 malocclusion with severe labioversion of upper anterior teeth and severe overjet, and in class Ⅱ malocclusion with infraversion of bilateral maxillary canines by MEAW mechanics, which enables us to get effective distal en mass movement of maxillary dentition, with upper second molar extraction. After treatment, there were natural contact points at canine and premolar regions, normal occlusal relationship and treatment results, satisfied the gnathologic concept, in this 2 cases. Compared with the routine treatment with premolar extraction, the treatment time and patients' discomfort were reduced. And the MEAW mechanics, which enables us to get effective distal en mass movement of maxillary dentition, resulted in reduction of the treatment time and getting the good treatment results. Consequently, the major concerns in orthodontic treatment are appropriate diagnosis and treatment plan, so, the application of second molar extraction with appropriate case analysis and diagnosis is very helpful to orthodontic treatment.

자연과 수업시 교사가 아동에게 제공하고 있는 뇌친화적 요소에 관한 연구

임채성,김병철,류양순,이영아 부산교육대학교 과학교육연구소 1999 科學敎育硏究 Vol.24 No.-

Educational practices should be based on the sound information about the structure and function of human brain. Recently, with the result of advancement in technology, inner workings of our brain were sufficiently accumulated to actually apply to the educational practices. The eight brain-compatible elements suggested by Kovalik & Olsen(1994) were based on these knowledge about brain. This study was undertaken with the purpose of providing insights into science teaching-learning based on the brain-compatible elements derived from several brain-based learning principles. To accomplish this purpose, we explored how the elements were provided to children by teachers in science instruction. The results as follows. The levels of appreciation of the elements by teachers were high. Especially, the appreciation element of cooperation in science teaching was relatively higher than those of others. Furthermore, they had attitudes to have children relate the science subject to their real lives. For one particular element, that is, enriched environment, it was found to be relatively less appreciated, probably because of the lack of resources such as books, videos, CD, pictures, regularly scheduled guest speakers, and the others to support science contents. These findings provide a basis for understanding the roles of the brain-compatible elements in learning science. The results also highlight the need for teachers to aware of and implement the elements to create environments which encourage the maximization of the brain potentials of children when teach science subjects.

대학 평가 내용 분석 및 체제 개선 연구

오성철,이혁규,양갑렬 淸州敎育大學校 初等敎育硏究所 2004 初等敎育硏究 Vol.14 No.-

로드셀을 이용한 고속 감자 중량계량법

김상철,임종환,김귀식,김성근,양종훈 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

Potatos, together with tangerines, are one of the major agricultural products in Jeju, and the production account for more than 30% of the domestic production. Recently some kinds of sorting machine for potatos are available, but they are not extensively used because their performance is not satisfactory and/or they are very expensive. This paper presents a load based high speed weighting method for sorting the potatos. This method is based on the fact that the linear momentum of a potato is proportional to the mass of it. The usefulness of the method is demonstrated with sets of experiments.

포자배양에 의한 박쥐란 (Platycerium bifurcatum (Cav.) C. Chr.)의 대량증식과 순화재배에 관한 연구

姜聲述,梁會亨,曺敬喆,金光秀 全南大學校 農業科學技術硏究所 1998 農業科學技術硏究 Vol.33 No.-

박쥐란(Platycerium bifurcatum (Cav.) C. Chr.)의 기재 대량 증식과 순화배지 개발을 목적으로 포자발아에 적합 배지, 유식물의 발근율 향상을 위한 생장조정제 종류 및 활성탄소의 농도를 구명하고 훈탄, 수태, 바크와 왕겨, 피트와 퍼라이트 및 버미큐라이트와 퍼라이트 등 몇가지 재식 재료의 종류가 박쥐란 유묘의 생육에 미치는 영향에 관하여 알아 보고자 실험은 실시하였다. 포자의 발아는 agar 보다 gelrite 첨가배지에서 좋았다. 포자체의 성장에는 MS 배지 보다 hyponex, Knudson 배지가 좋았다. 생장조정제 종류의 영향에 있어서는 shoot 발생에는 IAA와 NAA 첨가배지에서 양호했고 rooting은 NAA 첨가배지에서만 발생하였다. 활성탄소의 종도에 따른 shoot 발생과 지상부생육은 0.3%에서 가장 양호했고 뿌리수도 같은 경향으로 적정 농도는 0.3∼0.6%였다. 특히 활성탄소의 농도 그 이상인 경우는 근부 발달이 현저히 억제되었다. 유묘의 순화는 훈탄과 수태단용, 피트 + 퍼라이트에서는 신초수, 지상부 및 지하부 생육이 양호한 반면 바크와 왕겨 혼합용토는 식재재료로 부적당하였다. This study was carried out to establish a mass-propagaion system of Platycerium bifurcatum (Cav.) C. Chr. through in vitro culture of spores. Effects of growth regulator and activated charcoal on the in vitro plant development from spores were examined, and an ideal potting material for acclimatization of the sporelings was developed in this experiments. Gelrite was better than agar as gelling agent of the media for spore germination. The gametophytes grew better on hyponex or Knudson medium than on MS medium. The culture medium with IAA and NAA was better for the plant shooting and rooting than the medium containing NAA only. Multiple shoot formation as will as shoot and root growth was promoted by the addition of activated charcoal aat 0.3% to the culture medium, byt, the plant growth, especially root development was retarded when the concentration of charcoal exceeded 0.6% in the culture medium. Carbonized rice hull, sphagnum moss or peat with perlite in pot mixture resulted in the desirable shoot and root growth.

충수염의 임상적 고찰과 초음파의 유용성

박정배,양혁준,김형수,황성연,박철완,이근 대한응급의학회 1995 대한응급의학회지 Vol.6 No.2

Appendicitis is the most common acute abdomen in Emergency Medical Center & outpatient department. But sometimes, it is difficult for us to diagnose because of clinically variable symptoms. We reviewed the ultrasonographic findings and analyse 521 cases of appendectomy patients about its distribution of sex and age, seasonal prevalence, clinical symptom and signs, laboratory findings, duration from onset of symptom to arrival at hospital, duration from arrival at hospital to operation, vital signs, operative results, and associated diseases, which were treated at the department of General Surgery & Emergency Medical Center in Chung Ang Gil Hospital from July, 1994 to June, 1995. The results were as follows : 1. The most common age group was second decade. And male to female ratio was 1.43:1. Seasonal variation was not significant. 2. Of 521 cases, 141 cases(27.1%) visited the hospital within 24 hours from the onset of symptom, and 259 cases(49.7%) visited between 24 to 48 hours. 3. In duration from arrival to operation, the cases within 6 hours were 263 (50.5%), the cases between 6 and 12 hours were 131(25..1%). 4. In systolic blood pressure, cases below 90mmHg were 19(3.6%), cases above 160mmHg were 23(4.4%). Below 60mmHg diastolic pressure were 55 cases(10.6%), cases above 110mmHg were 9(1.7%). In pulse rate, above 90 rate/min were 171(32.8%). 5. On admission leukocytosis was found in 413 cases(79.3%) and 342 cases of them were pathologic appendicitis. 6. Ultrasoundgraphy was performed in the 87 cases, but 23 cases were suggested appendicitis. Among 23 cases, 22(95.7%) revealed pathologic appendicitis at ooperation and labortatory examination. Of the 64 cases which were normal on ultrasonography, only 2 cases(3.1%) were proved to be appendicitis. 7. The results of 496 operations without ultrasonography were appendicitis in 390 cases(78.6%), mesenteric lymphadenopathy 36(7.3%), pelvic inflammatory disease 28(5.6%), fecalith 15(3.0%), terminal ileitis 8(1.6%), diverticulitis 7(1.4%), urinary tract stones 5(1.0%), cecal cancer 2 cases, right ovarian tumor 2 cases, tubo-ovarian abscess 2 cases, grater omentum internal hernia 1 case. Our results showed that the sensitivity of ultrasonohraphy was 95.8% and the specificity 98.4% in the diagnosis of appendicitis, It suggests that the ultrasonography is very helpful in the diagnosis & differential diagnosis of acute appeendiditis.

한국형 교정치료용 Bracket의 개발에 관한 연구

장영일,양원식,남동석,문성철 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.5

한국인의 치열의 특성을 고려한 Straight-Wire Appliance(SWA)의 제작을 위한 자료를 얻기 위하여 18세 이상 25세 사이의 한국인 성인 정상교합자를 1) 구강악안면부에 기능장애가 없고, 2) 양호한 치열궁 형태와 긴밀한 구치부 교합 관계를 가지며, 3) 교합이 전후방적으로 앵글 분류 I급의 관계를 가지며, 4) 간단한 수복 치료 외에 교정치료나 보철치료를 받지 않았으며, 특히 치아의 순면과 협면의 형태에 변형을 초래한 치과 치료를 받지 않았으며, 5) 단정한 안모를 가진 자를 선발 기준으로 정하여 선발하였다. 선정된 정상 교합자의 상, 하악 인상을 채득하고, 교정용 석고 모형을 제작하였다. 얻어진 치과 석고모형을 분석하여, Andrews의 Six keys to optimal occlusion에 부합되는 표본을 5 명의 숙련된 교정의사들이 선별하여 한국인 성인 정상교합자 치열의 석고 모형 155 쌍(남자 92쌍, 여자 63쌍)을 얻었다. 이들을 대상으로 정밀측정장비인 Coordinate Measuring Machine(CMM, MPC802, WEGU-Messtechnik, Germany)을 이용하여 3차원 digitization을 시행하고, 계측프로그램을 작성하여 SWA 제작을 위하여 필요한 Angulation, Inclination, In-and-Out, Molar offset angle, Arch-form 등을 측정하였다. 측정을 시행하기 전에, CMM을 이용한 3차원 digitization의 오차에 대한 검증을 실시하였고, 3차원 digitization과 컴퓨터를 이용한 형태학적 분석법과 기존의 수작업에 의한 분석법의 신뢰도에 대한 분석을 실시하였다. 이상의 연구를 통하여 얻은 결론은 다음과 같다. 1.치과 석고모형의 3차원 digitization에 CMM을 적용하여 mesh size 0.25 mm,0.5 mm, 1.0 mm로 등간격 디지타이징하는 것은 모두 받아들일 수 있으며, 측정의 효율성을 고려할 때 1.0 mm 간격으로 등간격 디지타이징 하는 것이 바람직하다. 2.3차원 digitization과 컴퓨터를 이용한 방법이 Andrews의 방법에 기반한 수작업 방법보다 신뢰성이 높다. 3.3차원 digitization과 검퓨터를 이용한 방법으로 한국인의 치열의 형태학적 특성에 맞는 SWA의 제작을 위한 자료를 채득하였다. The aim of this study was development of the Straight-Wire Appliance(SWA) suitable for the treatment of Korean. To accomplish the object of this study, Korean adult with normal occlusion were selected with following criteria : 1) no functional abnormality in the craniofacial area, 2) good dental arch form and posterior occlusal relationship, 3) Angle Class I occlusal relationship, 4) no experience of orthodontic, nor prosthodontic treatment, especially, no dental treatment on labial and buccal surfaces of teeth, 5) good facial profile. Impression were taken for upper and lower dental arches of the selected normal occlusion samples and the orthodontic dental stone models were fabricated. 5 well-trained orthodontists had examined the acquired dental stone models to select study samples which satisfy the Six keys to optimal occlusion of Andrews. 155 pairs of dental stone models (92 pairs of Male, 63 of Female) were finally selected. 3 dimensional digitization were performed with the Coordinate Measuring Machine(CMM, MPC802, WEGU-Messtechnik, Germany) and measuring of Angulation, Inclination, In-and-Out, Molar offset angle and Arch form were accomplished with a measuring software to achieve data for the development of SWA. Before the measurement, error study was performed on the 3 dimensional digitization with CMM, and the analysis of reliability of computerized measuring method adapted in this study and conventional manual method presented by Andrews was performed. Results of this study were as follows : 1.Equi-distance digitization with mesh size 0.25 mm, 0.5 mm and 1.0 mm were acceptable in 3 dimensional digitization of dental stone model with the CMM, and the digitization with 1.0 mm mesh size was recommendable in terms of efficiency. 2.Computerized measuring method with 3 dimensional digitization was more reliable than manual measuring method of Andrews. 3.Data were collected for the development of SWA suitable for the morphological characteristics of Korean with the computerized measuring method with 3 dimensional digitization.

직업적 아크릴아미드 폭로에 의한 다발성 신경병증

정해관,권용욱,어경윤,김병준,양정선,정철,진영우,이미영,강성규 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.3

Authors report a first Korean case of polyneuropathy in an acrylamide producing factory together with an environmental and epidemiologic survey for the ten workers of the same workplace and 46 workers in the production and manufacturing acrylamide in Ulsan, Korea. The case is 30 years old man who worked in the production of the acrylamide for two years. In August, 1997, he had a weakness of the lower extremity with loss of body weight of 15 Kg which progressed to paresthesia of the limbs, the loss of vibration sense, difficulty in walking, speech disturbance, dysuria, constipation, difficulty in erection and swallowing difficulty. Neurologic examination showed a complete loss of vibration and position sense, and loss of deep tendon reflex in all the limbs. There was a contact dermatitis-like skin lesion on the feet. Electrodiagnostic test showed a generalized polyneuropathy of moderate degree involving motor and sensory component of peripheral and cranial nerves. After 8 months' cessation from exposure and supportive care, his symptoms were completely resolved, but abnormality in electrodiagnostic test and vibrotactile perception threshold still persisted, although much improved than before. There were 11 workers in the same workplace of the case, producing acrylamide by microorganism as a catalyst. Environmental monitoring of the workplace revealed air borne concentration of the acrylamide to be from 0.05 to 0.23 mg/m3 by personal sampling and from 7.65 to 11.65 mg/m3 by area sampling during filter exchanging process, which far exceeds TLV-TWA of 0.03 mg/m3. However, acrylamide was not detected from the plasma of the workers. Symptom questionnaire showed a markedly higher complain of neurologic symptoms, compared to the workers of the other acrylamide producing companies. Electrodiagnostic test showed a several workers are in the lower normal range without definite abnormality. Vibrotactile perception threshold by Vibratron Ⅱ showed a significantly increased threshold in the workers of the same workplace compared to the other acrylamide workers and significantly decreased test score of color vision compared to normal controls. After improvement of the production process and strict wearing of the protective device, most workers reported the improvement of clinical symptoms, but vibrotactile perception threshold was not improved. These result suggests the need for the effective environmental monitoring together with a periodic biological monitoring. Development of effective screening test is urgently needed to control and assess the skin absorption of acrylamide.