배관부 부식 및 결함 평가를 위한 레이저 유도 초음파 적용 기술

최상우,이준현,조윤호 한국비파괴검사학회 2004 학술대회 논문집 Vol.- No.-

There are many tube and pipe-line in nuclear power plant under high temperature and high pressure. Erosion and corrosion defects were expected on these tube and pipe-line by environmental and mechanical factors. These erosion and corrosion defects can evaluated by ultrasonic technique. In these study, Scanning Laser Source(SLS) technique was applied to detect defect and construct image. This technique also makes detection possible on rough and curved surfaces such as tube and pipe-line by scanning. Conventional ultrasonic scanning technique requires immersion of specimen or water jet for transferring ultrasonic wave between transducer and specimen. However, this SLS technique does not need contacting and couplant to generate surface wave and to get flaw images. Therefore, this SLS technique has several advantages, for complicated production inspection, non-contact, remote from specimen, and high resolution. In this study, SLS images were obtained with various conditions of generation laser ultrasound and receiving in order to enhance detectability of flaws on the tube. Stress corrosion cracks were produced on tube and imgaes of stress corrosion cracks were constructed by using SLS technique.

술전ㆍ후 상악동염환자와 정상인의 상악동 크기 및 골벽두께에 관한 전산화단층방사선학적 연구

최선영,이상래,고광준 대한구강악안면방사선학회 2000 Imaging Science in Dentistry Vol.30 No.2

Purpose : To compare the size and bone wall thickness of the maxillary sinus in normal, preoperative and postoperative maxillary sinusitis patients. Materials and Methods : The author analyzed CT images of both left and right maxillary sinuses in 357 patients who visited Chonbuk National University Hospital between January 1997 and December 1998. The size and bone wall thickness of the maxillary sinus of normal, inflammatory and post-Caldwell-Luc groups were compared. Results : The significant differences of transverse, maximum medio-lateral, maximum supero-inferior dimensions and medio-lateral dimension at nasal floor level between normal and post-Caldwell-Luc groups were found (P<0.05). And the significant differences of antero-posterior dimensions between inflammatory and post-Caldwell-Luc group were found(P<0.05). But, no significant differences of vertical height dimensions between groups was found(P> 0.05). The significant differences of postero-lateral, infero-lateral and medial wall thickness between normal and post-Caldwell-Luc groups were found (P< 0.05). Conclusion : The results of this study will aid in the diagnosis and treatment of maxillary sinus diseases and post operative treatment Planning, (Korean J Oral Maxillofac Radiol 2000 ; 30 : 109-116)

영아에서 발생한 골수섬유증 1례

최성민,이동석,권경배,김두권,김나연,원유흥,이준희,권영무 동국대학교 경주대학 1996 東國論集 Vol.15 No.-

특발성 골수섬유증은 만성 골수증식성 질환의 하나로 말초혈액도말에서 백적아구증, 부동변형적혈구 눈물방울세포 소견을 보이며, 골수 생검상 망상 섬유와 교원섬유로 구성된 섬유조직이 증가하는 골수의 섬유화 소견을 보이며, 골수외 조혈작용으로 인한 대상적 비장·간장 종대를 특징으로 하는 소아에서는 극히 드문 질환이다. 저자들은 본원에 복부종괴와 안면창백으로 입원하였던 8개월된 남아에서 임상증상, 말초혈액검사, 골수생검에서 특발성 골수섬유증으로 진단되어 Methylprednisolone 대량 정주 요법으로 치료하였으나 진단7개월만에 패혈증과 심부전으로 사망했던 1례를 경험하였기에 문헌고찰과 함께 보고하는 바이다. Idiopathic myelofibrosis is a chronic myeloproliferative disorder characterized by anemia, leukoerythroblastosis, anisopoikilocytosis, tear-drop cell, extramedullary hematopoiesis with hepatosplenomegaly and varying degrees of myelofibrosis of bone marrow. The mean age is about 60 years, and pediatric cases are rare. We experienced a case of idiopathic myelofibrosis in a 8 months old male who was presented with pallor, huge splenomegaly, leukoerythroblastosis in peripheral blood, myelofibrosis in bone marrow biopsy. We presented a case of idiopathic myelofibrosis with brief review of the literatures.

2차 공기 주입 조건 변화에 따른 소형 소각로 내부의 유동장 분석

최병대,김성준 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

This analysis is aimed to find out how the conditions of secondary air injection affects the residence time and the turbulence energy of flue gas and flow field in a small incinerator. A commercial code, PHOENICS, is used to simulate the flow field of an incinerator. The computational grid system is constructed in a cartesian coordinate system. In this numerical experiment, an independent numerical variable is the conditions of secondary air injection and dependants are the residence time of flue gas and the mean value of turbulence energy in a primary combustion chamber. The flow field and the distribution of turbulence energy are analysed to evaluate the residence time of flue gas and the turbulence energy. The computational results say that the tangential injection of secondary air make the residence time much longer than the radial injection and that the radial injection of secondary make turbulence much stronger than the tangential injection.

골다공증에 의한 압박 골절의 치료에 있어서 경피적 추세 성형술의 의의

최재영,윤승환,조준,문창택,장상근 건국대학교 의과학연구소 2001 건국의과학학술지 Vol.11 No.-

Percutaneous vertebroplasty has recently been introduced as a therapeutic alternative for the treatment of pain associated with osteoporotic compression fractures and performed popularly at a few centers by neurosurgeons. This technique allows marked pain relief through stabilization of microfractures and strengthening of weakened vertebral body. Authors retrospectively analyzed the clinical outcome of 100 patients with osteoporotic compression fractures for investigating the therapeutic effectiveness of percutaneous vertebroplasty. They were treated with vertebroplasty from April to August 1999. Plain X-ray of all patients showed osteoporotic compression fractures at more than one level.

Er:YAG 레이저를 이용한 치아삭제 효과

최남기,양규호,박상원,김옥준 大韓小兒齒科學會 2001 大韓小兒齒科學會誌 Vol.28 No.4

Er:YAG 레이저는 파장이 물의 주흡수 정점과 일치하는 2.94㎛의 방출파장을 가지기 때문에, 물분사를 하면서 사용했을 때, 다른 레이저보다 열손상은 더 작으면서 치아경조직을 보다 효과적으로 삭제한다고 알려져 있다. Er:YAG 레이저의 상아질 삭제 효과를 평가하고자 발거된 소구치와 대구치를 대상으로 상아질 시편을 제작하고 2.94㎛의 pulsed Er:YAG 레이저 (SDL-300EN, 삼성전자, 한국)를 handpiece형의 전달계를 이용한 비접촉식 방법으로, 물에 담궈진 시간과 레이저 조사시간에 따른 삭제량과 형태를 조사, 분석하여 다음과 같은 결과를 얻었다. 1. 건전 상아질에 대한 조사 결과 물에 담군 시간이 증가할수록 삭제율이 증가 하였다. 2. 건전 상아질과 우식 상아질에 150mJ, 10Hz의 조건으로, 30초간 레이저를 조사했을 때, 우식상아질에 비해 건전 상아질에서 surface irregularity가 증가하고 상아세관이 열리는 경향이 있었으며 crack이 관찰되었다. 또한 우식 상아질에 비해 많은 탄조각(ash flecks), crack이 관찰되었고 상아세관의 불연속성(inconsistency)이 관찰 되었다. 3. 우식 상아질에서 30초로 조사한 경우에서는 dark zone이 와동에 국한되어 나타났으며 작은 fleck들이 관찰되었고, 1분간 조사한 경우에서는 30초의 경우보다도 와동이 더 넓었으며, crack이 상아세관 주행방향과 직각으로 형성된 것을 관찰 할 수 있었다. 2분간 조사한 경우는 와동이 가장 넓었으며 crack이 더 많이 형성된 것을 볼 수 있었다. The purpose of this study was to evaluate the effects of Er:YAG laser on cutting efficacy and its histologic findings. Dentin specimens of human premolars and molars were used and irradiated by Er:YAG laser with noncontact handpiece type delivery system under different treatment condition of irradiation tiem. Cavity pattern and volume were evaluated to determine the cutting efficacy and following results were obtained. 1. Cutting volume of sound dentin was getting larger with time immersed in water increase 2. With the condition of irradiation (150mJ, 10Hz, 30sec), surface irregularity was more increased in sound dentin comparing to carious dentin. For the light microscopic examination, dentinal tubules were opened and ash flecks and cracks were noted with inconsistence of dentinal tubules. 3. In case of 30 sec, irradiation in carious dentin, dark zone was limited to small focus whereas 1 min, irradiation, more wider, and cracks were noted in the perpendicular to direction of dentinal tubules. For the 2 min, irradiation, cavity was the widest and more cracks were found.

이데올로기의 否定的 機能에 관한 硏究

崔俊成 상명대학교 논문집 1983 상명대학교논문집 Vol.12 No.-

Ideology does not constitute truth in the sense of science and philosophy, yet it has a great potential to influence human life, especially in the areas of politics, economics, and culture. An ideology is a form of social or political doctrine, which functions in two directions, namely positive and negative. This study's research goal is to inquire into the contents and causes of the negative function of ideology and to discover the methods of the conquest of negative ideology with regard to Marxism. The results of the negative function of ideology are as follows: first, the function of temptation, second, of oppression, third, of confinement, fourth, of despotism,and fifth, of destruction. The causes of the negative function of ideology are as follows: first, the preservation of the ruling power or the governing class, second, the self interest of human beings, third, the confusion of factual judgement with value judgement, fourth, the intermingling of natural scientific methods and social scientific methods, fifth, the indescriminate use of relative truth and absolute truth, sixth, ideology as empty form is subject to abuse, and seventh, the tendency for illusion in human nature. Ideology, may be truth in the practical sense but not in the theoretical sense. It is a system of ideas which aspires not only to explain the world but to change it. Therefore, it must be controlled in order to contribute toward increasing the self-realization of the individual and the welfare of human society as a whole.

6주간의 淸暑益氣湯 經口投與가 에너지대사 및 호르몬 변화에 미치는 영향

최용어,강명신,유종만,이규성,오재근,조준용 韓國體育大學校附屬 體育科學硏究所 1994 韓國體育大學校附屬 體育科學硏究所論文集 Vol.13 No.1

The purpose of this study was to investigate the effects of chung-seo-ik-gi -tang administration on the metabolic responses and hormones in 18 healthy-male elite boxes. All subjects were divided randomly with two groups, Chung-sea-ik-gi-tang Group(N=18) and placebo group(N=18) and perfored with 70% of HR max using bycicle ergometer unfil exhaustion. During the submaximal exercise, heart rate was maesured every two min. The blood samples were collected from antecubital vein by 10ml syranges(6ml/each) before immediately after exhaustion, recover-10 min, recover-20 min and recover-30 min. The samples were to analyzed for the level of glucose, lactate, TG, TC, HDL-C, insulin and catecholamine. The results of various blood parameters were summarized as follow; l. Energy substrates (plasma glucose, TG, TC, HDL-C) changes in group C were significantly different from group P. Plasma glucose in group C was significantly lowered at recover-10 min compared to group P (P<0.05). and also TG, TC and HDL-C in group C were significantly increased after 3 weeks compared to group P (P<0.05) whereas. Lactate accumulation in group C was significantly decreased after 3 weeks compared to group P (P<0.05). 2. Plasma insulin level was not showed significant difference between two groups. But insulin depression tendency after 3, 6 weeks in group C was allevated compared to group P. Increasing rate of norepinephrine in group C at Post-exhaustion after 3weeks lowered compared to group P. Norepinephrine in group C at rest periods after 3 weeks showed significant difference compared to group C. The results indicated that Chung-seo-ik-gi-tang had the effects of ergogenic aids on fatigue resistance and recovery from exhaustive exercise at the level of 70% HR max.

원자로 스터드 볼트의 비파괴 평가를 위한 초음파 Phased Array 기법 적용

최상우,이준현,박문호,박민수,조윤호 한국비파괴검사학회 2004 학술대회 논문집 Vol.- No.-

The stud bolt is one of crucial parts for safety of reactor vessels in nuclear power plants. Cracks initiation and propagation were reported in stud bolts using closure of reactor vessel and head. Stud bolts are inspected by ultrasonic technique during overhaul periodically for the prevention of stud bolt failure and radioactive leakage from nuclear reactor. In conventional ultrasonic testing for inspection of stud bolts, crack was detected by using shadow effect. It take too much time to inspect stud bolt by using conventional ultrasonic technique. In addition, there were numerous spurious signal reflected from every thread. In this study, the advanced ultrasonic phased array technique was introduced for inspect stud bolts. The phased array technique provide fast inspection and high detectability of defects. There are sector scanning and linear scanning method in phased array technique, and these scanning methods were applied to inspect stud bolt and detectability was investigated.

灰鑄鐵의 磨減特性에 미치는 微量合金 元素의 影響

최광림,박상준 大田開放大學 1985 論文集 Vol.3 No.-

Specimens of the gray cast iron which were added small amounts of alloy elements (Ti, V, Sn, p, Nb, B, Mo, Ni, Cu, Cr) were casted into green sand mold and centrifugal easting mold. Both, the microstructures and wear characteristics of the samples are studied. The result are as follows. 1) The centrifugal castings are more large amounts of 1-2% carbide and less size of 0.01-0.04 mm graphite than the green sand mold castings at the same composition. 2) Under the present experimental conditions, the relationship between the abrasion speed and the abraded amount are : 0.6 m/sec for maximum abrasive wear of the green sand castings, 1.4 m/sec for maximum abrasive wear of the centrifugal casting. 3) Wear-resistance of the unalloyed centrifugal castings is more excellent than the green sand castings, which alloyed small amounts with Ti, V, Sn, Mo, Cu, Ni and Nb element. 4) The cast Iron with phosphorus and boron elements have excellent wear-resistance than the cast iron with other elements at dry wear condition.