Fractal 차원에 의한 표면경화면과 마찰면의 형태해석

문병주,조연상,옥철호,박흥식,전태옥 동아대학교 생산기술연구소 2001 生産技術硏究所硏究論文集 Vol.6 No.1

The determination of surface middleography is believed to be extremely important in the areas of contact mechanics, adhesion and friction. In order to describe middleography of various rubbed and hardened surface, the wear test was carried out under different experimental conditions in dry friction. And fractal descriptors was applied to rubbed and hardened surface of laser modified steel with image processing system. These descriptors to analyze surface structure are fractal dimension. Surface fractal dimension can be determined by sum of intensity difference of surface pixel. middleography of rubbed and hardened surface can be effectively obtained by fractal dimensions.

도금사업장의 작업환경의 유해인자 노출수준에 관한 연구

문덕환,도수영,이채관,황용식,선병관,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : For the purpose of preparing the fundamental data and assessing the status of exposure level of chemical substances and physical agents. Methods and Material : Such as noise, two types of dust, four types of metals, seventeen types of organic solvents, and four types of other materials classified by specific chemical substances in 21 metal product plating factories classified by 28 processes. The author determined exposure level on those hazardous materials from Jan. to Dec. 2001. Results : The results were as follows: 1. The exposure level for noise was exceeded to Threshold Limit Value(TLV) in the process of 6 cases of Machining, 5 and 4 cases of pre and post-buffing, and 6 cases of waterdrop-removing, the mean noise level of all of processes was not exceeded to compliance level. 2. The exposure level for dust was not exceeded to TLV at all. 3. The exposure level for Chromium(Cr) was exceeded to TLV in Chromium plating process, metal exposure level including Zinc(Zn), Manganese(Mn), and Lead(Pb) was not exceeded to TLV. 4. The exposure level of toluene in case of organic solvents was exceeded to TLV in 1 case of finishing/cleaning, coating/developing process, respectively. 5. The exposure level of four types of other materials classified by specific chemical substances were not exceeded to TLV. 6. The exposure level for dust and metal including Zn, Mn, and Pb was decreased in comparison with two results of air monitoring performed. There was no difference of the exposure level for Cr, noise, and four types of other materials classified by specific chemical substances, and the exposure level for organic solvents was slightly increased. 7. The exposure level for noise in factories employing more than 21 workers was higher than that for noise in foadtories employing less than 20 workers. The more workers, the lower exposure level in metal including Zn, Mn. The exposure level for Cr was increasing in factories employing more than 51 workers, and the more workers the lower exposure level in organic solvents. Conclusion : According to above results, this study suggests positive work environment managements in processes exceeding exposure limit value as well as continuously consecutive work environment management in processes not exceeding exposure limit value and revealing no chronological difference of exposure level should be needed.

마멸입자 형태해석에 의한 유압피스톤용 모터의 상태감시

문병주,조연상,박흥식,전태옥 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.6

Morphological analysis of wear particles is one of useful methods for machine condition monitoring because it is well reflected in machine driving state. This paper was undertaken to apply to the condition monitoring of hydraulic piston motor. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) arc used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of calculating presumed wear volume for three kinds of mate-rials on driving time to foresee a damage condition of lubricating materials.

응급실에 내원한 환자에서 어지럼증의 원인과 임상양상의 분석

문원식,정경운,위준선,문정미,전병조,김용권,소정일,류진호,허탁,민용일 대한응급의학회 2001 대한응급의학회지 Vol.12 No.3

Background: Recently, The number of patients who have been complaining of the vertigo or dizziness has been increasing due to rapid growth of elderly population and senile disease. The differentiation of dizzy patients is not familiar to most emergency physicians. This study was designed to differentiate true vertigo and to investigate the clinical difference among central vertigo, peripheral vertigo, and other causes of dizziness. Methods: The authors analyzed the cases of 237 dizzy patients who visited the emergency department of Chonnam University Hospital during the recent 2 years. For the base of dizziness, associated past illnesses, severity, nystagmus type, and the causes of central and peripheral vertigo. Results: Female patients were 142(59.9%) and male patients were 95(40.1%). The most common age group was the 6th decade. The origin of dizziness was classified as peripheral cause(25.3%), central cause(32.9%), and others(41.8%). As to nature of the dizziness, the rotatory sense was dominant in peripheral vertigo and the floating sense and blurred vision in central vertigo. Peripheral vertigo was triggered by position change of head and body, and central vertigo by the eye movement. Audiograms I showed that most patients with central vertigo had normal hearing, but 46.7% of thoswith peripheral vertigo had an abnormal hearing disturbance. Nystagmus was more prevalent in peripheral vertigo Conclusion: History taking and physical examination played an important role in the diagnosis of dizzy patients. An important part of the diagnosis of a dizzy patient could be to evaluate the peripheral origin, the central origin and others causes. Because central vertigo may be associated with a significant neurological pathology, spectral radiological studies, including MRI and CT, are mandatory to rule out a devastating brain lesion.

Indium이 도핑된 Si/CeO_2/Si 박막의 발광 현상

문병식,김종걸,양지훈,박종윤 성균관대학교 기초과학연구소 1998 論文集 Vol.49 No.-

Visible light with about 500 nm was observed from the indium doped Si/CeO_2/Si thin films at room temperature. CeO₂, indium, and silicon were in sequence deposited on the Si(111) substrate using electron beam evaporation. As the indium was increased the peak intensity of 500 nm was increased. After furnace annealing in nitrogen at 1100℃ the peak was observed at 400 nm. Secondary ion mass spectrometry(SIMS) showed the mixed layer of CeO₂, indium, and silicon. It seems that the peak around 500 nm would come from the mixed layer.

구치부 복합레진의 적정 RADIOPACITY에 관한 연구

김병현,이정식,엄정문 大韓齒科保存學會 1992 Restorative Dentistry & Endodontics Vol.17 No.1

The aim of this study was to compare the accuracy of radiographic diagnosis of secondary carious lesions adjacent to composite filling materials with different radiopacity. The level of radiopacity that is most compatible with the radiographic diagnosis of secondary caries was studied in a two part experiment. In the first part, the radiopacity of 6 posterior composites (BP, CF, HM, LF, PQ, P50), enamel and dentin were measured by desitometer and 6 posterior composites divided into 3 groups based on their level of radiopacity compared with enamel and dentin. In the second part, class II composite fillings with or without secondary caries were made in extracted premolar and radiographs of the teeth were examined by 10 dentists to diagnose simulated carious lesion. The following results were obtained : 1. The radiopacity of 6 posterior composites varied between 1.76(PQ) and 6.78(P50)mm Al equivalent. 2. For 4 composites the radiopacity exeeded that of an equal thickness of enamel, and for two the radiopacity was lower than that of dentin. 3. The detection of secondary caries was facillitated when the radiopacity of a composite resin was similar to or slightly greater than that of enamel.

Dynamic Vehicle Scheduling for Pickup/Delivery Systems

이문규,박병춘,손유익,김태식 啓明大學校 産業技術硏究所 1996 産業技術硏究所 論文報告集 Vol.19 No.1

In this paper, we consider a vehicle scheduling problem with time windows where for each customer request either pickup or delivery operation is performed by a single vehicle. For the static case of the problem, a dynamic programming (DP) algorithm which generates exact solutions is developed. In this case, intermediate requests which may arrive during the excecution of the current route are not allowed. The approach is then extended to solve the equivalent dynamic case where new emergent requests are automatically included in the current route at the time they appear. The algorithm optimizes over all the known information and does not consider any future requests. To show the validity of the algorithm an example problem is solved.

간세포암과 감별이 어려웠던 악성중피종 치험 1예

김선문,허원석,채경훈,강윤세,정재훈,김연수,박기오,문희석,이엄석,김석현,성재규,이병석,이헌영,신경숙,조준식,송인상,강대영 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

Malignant peritoneal mesothelioma is a rare neoplasm that arises from the mesothelium of a serosal cavity and is a rapidly fatal disease with a median survival of 4 to 12 months for untreated cases. Recently, we experienced a case with malignant peritoneal mesothelioma who was suspected hepatocelluar carcioma by abdominal CT scan and was confirmed by biopsy including immunohistochemical stain(calretinin) after surgery. We performed tumor excisions and wedge resection of the liver(segment Ⅷ)and inserted Tencoff catheter in abdominal cavity at 25th day of post-operation. We treated with intraperitoneal paclitaxel(25mg/m^(2)/day for 5 days) six courses monthly. She was well tolerable and is still living without any evidence of recurrence for 14th month of post-operation.

TiN 박막 형성에 미치는 ion beam 조사 효과

안병건,추관식,문두수,안정식,김영대,김형자,이규용 釜慶大學校 2002 釜慶大學校 論文集 Vol.7 No.-

Low energy high current N_2 ion beam was used to modify the morphology and chemical composition of cemented carbide WC-Co(Co:10 wt%, TiC + TaC:15 wt%, WC:bal) hard material surface for the fabrication of the TiN thin film by sol-gel method. The effects of ion beam treatment on preparation of the TiN thin film by sol-gel mothod were investigated by XPS, SEM, AFM and GXRD. According to the N_2 ion beam bombardment, the surface roughness was increased and TiC binders in WC were dissolved. The dissolved Ti was recombind with nitrogen ion to form the TiN nucleuses which were acted as seeds for the forming of the TiN thin film on the cemented WC-Co surface. Besides, the sputter deposited Ti interlayer prevented the diffusion of TiO_2 sol into the porous WC-Co during the formation of TiN thin film.

밤가공공장의 밤껍질에서 밤분말의 생산에 관한 연구(Ⅰ) : 밤껍질에서 분리한 전분의 이화학적 특성연구 Study on Physicochemical Properties of Starch Separated from Chestunt Inner Shell

전병관,문정식 동신대학교 환경연구소 1998 환경연구 Vol.3 No.1

밤 가공공장에서 밤을 가공하는 공정에서 다량의 밤껍질이 폐기되고 있으며 이껍질속에는 밤살이 포함되어 있다. 이렇게 폐기되는 밤살을 회수하여 식품원으로 활용한다면 재원의 재활용차원에서 뿐만 아니라 가공공장의 수익에도 많은 보탬이 될 것으로 생각되어 밤껍질의 활용에 대한 기초적인 연구로서 밤분말을 제조한 후 만든 밤전분의 이화학적 특성을 규명하여 다음과 같은 결과를 얻었다. 1. 무기성분 함량은 밤껍질에서 분리한 전분이 순수한 밤에서 분리한 전분보다 평균 4.5배정도 많았다. 2. 껍질에서 분리한 전분의 탄닌함량은 순수한 밤에서 분리한 전분의 탄닌에 비하여 12배정도 많았다. 3. 물결합능력은 껍질에서 분리한 전분이 순수한 밤에서 분리한 전분보다 40%정도 높았다. 5. 순수한 밤에서 분리한 전분과 껍질에서 분리한 전분의 요오드반응결과 625nm에서의 흡광도는 유사하였다. 6. amylose 분해한도는 밤껍질에서 분리한 전분이 순수한 밤에서 분리한 전분보다 8.0%정도 높았다. Chestnut processing plants have produced large amount of chestnut inner skin waste, which contains chestnut flesh that can be recovered to be used as food ingredient. To obtain basic information needed for commercial application, comparative chemical analysis of starches extracted from both inner skin waste and chestnut core was performed. The results were as fellows: 1. Starch from the inner skin waste contains 4.5 times more inorganic compounds than the core starch. 2. Starch from the inner skin waste contains 12 times more tannin (or tannic acids) than the core starch. 3. Starch from the inner skin waste absorbs 40% more water than the core starch. 4. Both types of starches recorded comparable absorbencies at 625nm from Iodine Reaction. 5. Starch from the inner skin waste shows 8% higher amylase degradation than the core starch.