고속도강을 이용한 CFRP 복합재료의 드릴가공 특성

조규재,박종남,정용운 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.1

복합재료는 각 종 기계부품, 우주항공산업, 자동차의 내장재와 구조재, 건축구조물, 선박 재료, 스포츠용품 등 다방면에서 유용하게 사용되어지고 있다. 복합재료는 여러 가지의 대체 재료로서 타 산업에 비하여 활용의 가치가 높다. 그러나 기계가공분야에서는 가공의 어려움으로 인하여 활용도가 미흡한 상태이다. 따라서 본 논문에서는 CFRP를 수직형 머시닝센터에서 고속도강 드렬로 가공한 후 흘 가공 입 · 출구부에서 표면이 고르지 못함을 확인하였으며, 가공을 할수록 유동형의 긴 칩에서 분진형태로 변하는 칩의 형상 등을 관찰하였다. Composite materials are widely used in all kinds of machine parts, aerospace industries, internal and structural materials of cars, building structures, ship materials, sporting goods, and others. It is worth while to use the composite materials as various substitutions compared with others. But it is limited to use them in the field of the mechanical processing because of the difficulties in cutting. Thus it is proved that the surface roughness is in and out of the hole processing after cutting the CFRP with HSS drilling in the vertical machining center. And it is observed that the more it is processed, the more the fluid long chip is changed into the powdered chip.

생체내 심근허혈-재관류 모델에서 멜라토닌의 재관류 부정맥에 대한 심근보호작용에 관한 연구

조규종,김원,홍정석,이미우,장성은,오세현,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Recently, a few studies demonstrated that melatonin reduced the severity of myocardial reperfusion injuries, such as reperfusion arrhythmias. However, it is uncertain whether the melatonin reduces reperfusion arrhythmias in thus anesthetized animals because results were obtained using isolated hearts. Thus, to see whether melatonin reduces reperfusion arrhythmias in anesthetized animals, we examined the effect of melatonin on the incidence of reperfusion arrhythmias in an anesthetized-cat model of regional ischemia. Method: Adult mongrel male cats(n=30, 2.9∼4.2 kg) were anesthetized under positive-pressure artificial ventilation with room air. The animals of the control group(n=15) were subjected to 20-minute left anterior descending coronary artery(LAD) occlusion followed by abrupt reperfusion. The animals in experimental group(n=15) were divided into two. Group I(n=6) was pretreated with melatonin, 1 mg/kg, before occluding the LAD. Group II(n=9) was pretreated with melatonin, 10 mg/kg. The animals in experimental group were subjected to ischemia/reperfusion insult following drug treatment: melatonin was applied intra-peritoneally for 3 minutes just before LAD coronary artery ligation. The Fisher's exact test was used to compare the data from different animal groups. p<0.05 was considered significant. Results: The incidence of ventricular fibrillation(VF) during the reperfusion phase in group II(pretreated with melatonin, 10 mg) was significantly smaller than that in the control group(p-value = 0.0029). However, no statistically significant difference of VF incidence was found between group I(pretreated with melatonin, 1 mg) and the control group. Conclusion: Employing an anesthetized-cat model of regional cardiac ischemia, we investigated the dose-dependant effects of melatonin on reperfusion-induced arrhythmia. The cats pretreated with 10 mg/kg of melatonin before ischemia had a significantly reduced incidence of lethal reperfusion-induced arrhythmia, but there was no difference between the cats pretreated with 1 mg/kg of melatonin before ischemia and the control group.

高麗人蔘(Panax ginseng C. A. Meyer) 澱粉의 理化學的 特性

曺圭成,金海中 안성산업대학교 1996 論文集 Vol.28 No.-

This study was conducted to investigate the morphology and distribution of starch granule in ginseng root. The results obtained are as follows; The starch contents of 4 years and 6 years old ginseng root were 28.62~39.26% and 29.33%~41.02%, respectively. Thus the starch content of genseng root was different depending on the potion of ginseng root and growing periods. The starch granules showed nearly round or oval shape having the diameter 2~8.5μ and their size were increased with a growing period of ginseng. The amylose and amylopectin content ratio of ginseng starch was 17~18% and 82~83%, respectively. And amylose was decreased with a growing period of ginseng.

癌의 發生과 免疫에 대한 考察

조정효,손창규,조종관 대전대학교 한방병원 2001 惠和醫學 Vol.10 No.1

Most cancers are thought to originate from a single cell that has undergone a somatic mutation, but the progeny of this cell must undergo further changes, probably requiring several additional mutations, before they become cancerous. This phenomenon of tumor progression, which usually takes many years, reflects the operation of evolution by mutations and natural selection among somatic cells. The rate of the process is accelerated both by mutagenic agents (tumor initiators) and by certain nonmutagenic agents (tumor promoters). Thus many factors contribute to the development of a given cancer, and since some of these factors are avoidable features of the environment, a large proportion of cancers are in principle preventable.

고유량 고효율 혈액투석막 재사용의 임상경험

조현경,김승정,임병국,정혁준,최영일,마경애,신규태,김흥수,김도헌 대한신장학회 2001 대한신장학회잡지 Vol.20 No.3

다이빙 조사에 의한 가을철 가거도 연안의 어류상

명정구,조선형,박정호,백상규,김종만,강필선 한국어류학회 2003 韓國魚類學會誌 Vol.15 No.3

1. 2002년 10월 16∼17일에 스쿠버다이빙, 수중 촬영을 통하여 전라남도 신안군 가거도 주변 가을철 연안의 어류상을 조사한 결과 총 5목 23과 40종이 확인되었고, 지금까지 기재 된 어종 이외에 18종이 추가로 확인되었다. 2. 어종 구성으로 보면 양볼락과가 7종으로 가장 많았으며, 그 다음으로 둑중개과가 4종, 자리돔과가 3종 순이었다. 3. 가거도 주변에서 지금까지 확인된 어종들은 온대성 어종이 대부분이었지만, 그 외에 노랑자리돔, 청황베도라치 및 파랑돔 등 난류성 또는 아열대 어종이 확인되어 제주도나 독도와 마찬가지로 대마난류의 영향도 받고 있음을 나타내었다. The fish fauna in the coastal waters of Gageodo Island, South-west Sea, was investigated by SCUBA diving in October 16 and 17, 2002. The fishes observed were classified into 40 species in 23 families. In Autumn, subtropical fishes in such as families as Pomacentridae, Pomacanthidae and Apogonidae, represented 12.5% of the total, while eurythermal species represented 72.5%.

17β-Estradiol의 심근 보호작용에 대한 연구 ; 재관류 부정맥을 유발한 동물실험

홍정석,김원,조규종,이미우,장성은,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Although reperfusion certainly prevents tissue ischemia from possible cardiac death, several lines of evidence suggest that reperfusion may paradoxically aggravate the frequency of serious reperfusion-induced lethal arrhythmias. It has been reported that acute administration of estrogen at physiological concentrations reduced with myocardial ischemic injury in women with coronary heart disease. In studies with canines, acute administration by either the intra-muscular or the intra-coronary route similarly prevented ischemia and reperfusion dysrhythmias and also reduced the infarct size because the estrogen increased the distal coronary perfusion pressure, scavenged free radicals and had other effects during both ischemia and reperfusion. However, the canine heart is notoriously well collateralized. 17β-estradiol induces very little vasorelaxation in cat coronary rings, suggesting that increased ischemic myocardial blood flow dose not contribute to the protective effect. In the present study, employing a cat model of regional cardiac ischemia, we examined whether reperfusion rendered after acute administration of 17β-estradiol could lower the incidence of reperfusion-induced lethal arrhythmia and the death rate. Method: Adult mongrel male cats(n=31, 2.7∼4.5 kg) were anesthetized under positive-pressure artificial ventilation with room air. Electrocardiograms were recorded. The animals of the control group(n=15) were subjected to 20-minute left anterior descending coronary artery(LAD) occlusion followed by abrupt reperfusion. The animals in the experimental 17β-estradiol(2 or 20 ㎍/kg) group were subjected to ischemia/reperfusion insult following drug treatment: 17 β -estradiol was applied intravenously within the 60 seconds just before LAD ligation followed by abrupt reperfusion. The Fisher's exact test was used to compare the data from different animal groups(p<0.05). Results: The number of arrhythmias(ventricular premature beat, ventricular tachycardia and ventricular fibrillation) emerging during the reperfusion phase were not statistically different from that in the control group. The death rate in the 17β-estradiol 20㎍/kg group was lower from that in the control group(P value = 0.039). Conclusion: Acute administration of 17β -estradiol at a supraphysiological concentration might produce cardioprotective effects, not by modificating the coronary blood flow into the threatened myocardial region, but by other mechanisms that directly or indirectly increase the intrinsic myocardial ischemic tolerance in the cat during the reperfusion phase.

유방 절제술 후 조기 운동프로그램의 치료 효과

이규완,이충휘,조상현,박정미 한국전문물리치료학회 2001 한국전문물리치료학회지 Vol.8 No.1

The purposes of this study were to investigate the therapeutic effects of an early exercise program after mastectomy and to provide the early exercise program protocol for patients who had undergone mastectomy. The subjects were seventy women who were diagnosed with breast cancer. They were randomly assigned either to a experimental group (n=35) that received early postoperative exercise program or to a control group (n=35) that received only education by nurses. Data were obtained for each patient from goniometric measurements of shoulder flexion, abduction, external rotation, 10 elements of functional performance, and subjective pain evaluation using visual analogue scale (VAS). All variables were measured preoperatively, three days postoperatively, and one month postoperatively. Data were compared by groups using independent t-test and Mann-Whitey U test for parametric or non-parametric data, respectively. There were no significant differences between the groups for all variables preoperatively and at three days postoperatively. But there were significant differences at one month postoperatively. The experimental group showed a statisti-cally significant increases in shoulder flexion, abduction, and external rotation and in the pain VAS at one month Postoperatively (p〈,05). Also, at one month prostoperatively, the experimental group had less difficulty with three elements of functional performance-doing up a 'back' zippered article of clothing, reaching the ipsilateral scaula, and contralateral scapula with the fingers on the operated side- than the control group (p〈.05). The results of this study suggest that after mastectomy, the early exercise program conducted by a well-trained physical therapist can make a significant contribution to the return of more normal shoulder function and activities of daily living and to an increased quality of life.

유압관로에서 비정상유량의 속도분포에 대한 이론적 해석

유영태,조정규,최병재 조선대학교 에너지.자원신기술연구소 2001 에너지·자원신기술연구소 논문지 Vol.23 No.1

An efficient wave equation is analyzed for determining wave of taking into account viscosity and radial velocity and a oil hammer. Both frequency and transient response experiments are carried out with use of a rotary sinusoidal flow generator. The dynamic pressure of oil is measured and the obtained frequency characteristics are compared with the theoretical ones. Experimental and theoretical results make clear that the wave equation investigated here can predict wave phenomena in a wave transmission line containing a viscous liquid. i.e., in a hydraulic lines.

양 하지의 근력저하를 주소로 응급실로 내원한 원발성 알도스테로증 1예

안력,김원,조규종,홍정석,이미우,장성은,오세현,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

A primary central nervous system lymphoma(PCNSL) is defined as a lymphoma limited to the cranial-spinal axis without systemic involvement. PCNSLs were formerly very rare, only 0.5∼ 1.2% of all intracranial neoplasms, and were usually associated with acquired immuno-deficiency syndrome(AIDS) and other immune-compromised states. Recently, there has been a clear rise in the incidence of this disease among normal individuals. We describe a 77-year-old female with hyponatremia who presented with a confused mental state. Computed tomography(CT) of the brain demonstrated a suprasellar mass with enhancement. We evaluated the basic hormonal studies and the magnetic resonance imaging(MRI). A ventricular biopsy was done, and the result was a diffuse, large, B-cell-type malignant lymphoma. She presented panhypopituitarism and partial central diabetes insipidus. She received chemotheraphy and was discharged in an improved condition. We report a case of panhypopituitarism due to PCNSL and give a review of the literature.