NR과 SBR 가황물의 경도와 강성도에 대한 온도의 영향

진현호 ( Hyun Ho Jin ),홍창국 ( Chang Kook Hong ),조동련 ( Dong Lyun Cho ),강신영 ( Shin Young Kaang ) 한국고무학회 2007 엘라스토머 및 콤포지트 Vol.42 No.3

본 연구에서는 고무제품의 수치 안정성과 성능유지에 직접적으로 영향을 미치는 중요한 특성 중 하나인 온도변화에 따른 고무재료의 경도변화를 고찰하였다. 새롭게 제작된 International Rubber Hardness Degree(IRHD, Normal type) 경도측정 시험기를 사용하여 미충전된 NR과 SBR시편의 여러 온도에서 경도변화를 측정하였으며 Young`s modulus 값과 비교하였다. NR과 SBR 모두 유리전이온도 근처에서 경도와 Young`s modulus의 급격한 변화를 보였다. 온도가 증가함에 따라 경도와 Young`s modulus 값이 증가하는 경향을 보였으며 이는 분자의 운동성과 엔트로피 영향으로 해석할 수 있다. 카본블랙과 실리카가 충전된 NR과 SBR의 경우 충전제의 함량이 증가함에 따라 경도에 미치는 온도의 영향이 감소함을 관찰하였다. Hardness of rubbery materials, which is important for dimensional stability and product performance, was investigated upon temperature change in this study. A newly developed IRHD (International Rubber Hardness Degree) tester was used to measure the hardness changes of NR and SBR specimens at various temperatures and the hardness values were compared with the Young`s modulus. The hardness and Young`s modulus of NR and SBR showed an abrupt change near the glass transition temperatures. The hardness and Young`s modulus were increased by increasing temperature due to the increased random chain conformation of molecules. The effect of temperature on hardness and Young`s modulus of NR and SBR specimens filled with carbon black and silica was decreased by increasing filler content.

AN IN-SITU YOUNG'S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

Choi, Young-Chul,Yoon, Doo-Byung,Park, Jin-Ho,Kwon, Hyun-Sang Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.3

Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young's modulus becomes unreliable and in-situ measurement of Young's modulus is required from an engineering point of view. Young's modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young's modulus of two plates.

모체 Thyroxine 투여가 태아알코올효과를 가진 흰쥐 대뇌겉질 및 해마에서 NPY함유 신경세포의 생후 발달에 미치는 영향

김복,박상기,박영란,김종중,문정석,김주수,문영민,현영식,천관영,정윤영 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.2

Background and Objectives: Maternal alcohol abuse is considered to be one of the most prominent cause of neurobiological malformations in the postnatal and adult life of the offspring. In this study, we investigated the effects of maternal alcohol drinking on the postnatal development of NPY-containing neuron, and, the influence of thyroxine treatment on the cerebral cortex and hippocampus of pups of alcohol abused mother. Materials and Method: Time-pregnant rats were divided into three groups. Alcohol-fed group A received 35 calories of liquid alcohol diet daily from gestation day 6; control pair-fed group B was fed a liquid diet in dextrin replaced alcohol isocalorically: alcohol + T4 group C received 35 calories liquid alcohol diet and exogenous thyroxine subcutaneously. Results: Group C showed prominent NPY immunoreactivity in the cerebral cortex compared to group A and B at P7. In group C, NPY-containing neurons were widely distributed in the all layers of cerebral cortex after P14. Besides, numerical decrease of NPY-containing neuron as age increases was not found in group C. However, the decrease of NPY-containing neuron was clearly observed in group A compared to group C after P14. In hippocampus, group Band C were appeared similar patterns after P7. Additionally, in group C, NPY immunoreactivity was prominently appeared in CA2 and CA3 at P14 as compared to group B. Conclusions: The present results showed the increase of intensity and number of NPY-containing neurons in cerebral cortex and hippocampus of pups of exogenous T₄ supplemented alcohol-exposed dams as compared to control pair-fed and alcohol-exposed pups at P7. It presumably suggest that NPY-containing neurons might be regulated by the early postnatal growth stimulatory effect of the exogenously supplemented T₄. Therefore, the increase of NPY synthesis caused by maternal administration of exogenous thyroxine may ameliorate fetal alcohol effect, one of the ill effects as a result of the dysthyroid state following maternal alcohol abuse.

복합레진의 지연충전이 미세인장 결합강도에 미치는 영향

박현식,조영곤,박병철,김종욱,최희영,김종진,진철희,유상훈,기영재 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

The purpose of this study was to evaluate the effect of immediate or delayed composite resin filling on dentinal microtensile bond strength (μTBS) after applied the adhesive. The coronal dentin of human third molars was exposed. Single-Bond or One-Step was applied on the dentin surfaces, and composite resin were constructed immediately (group 1) or 5 min., 10 min., 15 min., 20 min. and 30 min. (groups 2-6) after an adhesive was applied. The specimens were sectioned and made bar-shaped. Each surface area of them was about l ㎟. The RBS test was performed by EZ test. The results were analysed by One-way ANOVA and Tukey's test at 95 % significance level. The results suggested that the μTBS of Single-Bond to dentin was decreased when the composite resin was constructed 20 min. and 30 min. after Single-Bond was applied. But the μTBS of One-Step was not affected by delayed composite resin filling.

유치 및 초기 영구치아의 치수 신경분포

김영진,남순현,김현정,이재문,이인정 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.2

유치 및 초기 영구치의 치수신경분포 및 변화를 평가하기 위하여 교정치료를 위해 발치한 치근흡수가 비교적 적은 유치,정상 탈락기의 유치,맹출중인 교합하지 않은 제 1소구치,맹출이 완료되어 교합하고 있는 1소구치를 대상으로 neurofilament protein(NEP)을 이용한 면역조직화학적 방법으로 관찰하여 다음과 같은 결과를 얻었다. 치근흡수가 비교적 적은 유치에서도 영구치와 유사한 신경총의 존재와 신경분포 형태가 관찰되었으나,영구치에 비해 그 신경분포 밀도가 낮았으며 분지형성 또한 미약하게 나타났고,전상아질로 진입하는 섬유의 수가 적었다. 정상탈락기의 유치에서는 신경의 변성으로 소포(vesicle),단절(fragmentation)등이 관찰되었으며,그 신경분포가 현저히 감소되어 나타났고,총상의 형태도 소실되었다. 교합하지 않은 제 1소구치에서 치수내의 신경은 말단가지의 숫자가 적고,치수 조상아 세포 경계에 도달하였으며,비교적 가는 신경 섬유가 많았다. 교합하고 있는 제 1소구치에서 치수내의 신경은 말단이 조상아층으로 진출하고,어떤 신경섬유는 전상아질층까지 진입하였으며,비교적 굵은신경 섬유의 분포가 많아졌다. The purpose of this study was to investigate the distribution of nerves in the dental pulp of early extracted primary teeth,normal exfoliated teeth,partially-erupted,nonfunctional,premolars,and erupted,functional,premolars.Numbers of sample were 10 teeth in each group. The distribution of nerves in the dental pulp were investigated by means of immunohistochemistry for detection of neurofilament protein(NFP). The results were as follows: The early extracted primary teeth exhibited patterns of innervation similar to those observed for young permanent teeth.The plexiform arrangement of fibers was not evident in the primary teeth.Most nerves appear to terminate about the odontoblasts. As primary teeth began to undergo root resorption,degenerative changes such as vesicles and fragmentation appear in nerves.The quantity of neural tissue also decreased.In teeth in which the roots were almost completely resorbed only a small number of nerves remain. There was a decrease in the number of terminal branches in the pulp of the partiallyerupted,nonfunctional,premolars and those present reached the pulpo-odontoblastic border. The nerve terminals in the pulp of the erupted,functional,premolars were traced to the dentinal tubule and a few nerve fibers formed loops in the predentin.

내시경적 조임근절개술후에 발생한 췌십이지장 가성동맥류 1예

박수영,김윤정,박진한,전현수,박시형,이영진,이은지,김지현 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

We reported a case of pancreatic pseudoaneurysm, involving pancreaticoduodenal artery, developed after endoscopic retrograde cholangiopancreatography(ERCP) with endoscopic sphinterotomy. A 54 year old woman was transferred to our hospital due to sustained hematochezia and hypovolemia. A week before admission, she underwent ERCP with endoscopic sphinterotomy for acute cholangitis in local clinics. She developed abdominal pain and hematochezia at 12 hours after the procedures. A post procedure contrast enhanced computed tomography of abdomen demonstrated a pseudoaneurysm in inferior portion of pancreatic head. This was not present on the pre procedure contrast enhanced computed tomography of abdomen and was thought to arise from the pancreaticoduodenal artery as a complication of the pre sphincterotomy. She was brought to our emergency room in a state of hypovolemia. A upper endoscopy showed active bleeding from ampula of vater. An celiac angiography demonstrated pancreatic pseudoaneurysm involving inferior pancreaticoduodenal artery and selective coil embolization of was performed.

인터넷 중독 청소년들의 정신병리 및 대처 방식

안영균(Young Kyun Ahn),신영철(Young Chul Shin),고복자(Bok Ja Koh),심진현(Jin Hyun Shim),김범조(Bum Jo Kim),이승민(Seung Min Lee),이길홍(Kil Hong Lee) 한국중독정신의학회 2005 중독정신의학 Vol.9 No.1

This study was conducted to investigate the differences in psychopathology and coping strategies among internet addictors, over users and non addictors in high school students. Subjects were 273 high school students in Seoul city. Self rating questionnaires included demographic data, Young’s Internet Addiction Scale, SCL-90-R, Beck Depression Inventory, Spielberger State-Trait Anxiety Inventory, and The Way of Coping Strategy. Subjects were classified into 3 groups (addiction, over use, non addiction) by Internet Addiction Scale score. Prevalence of internet addiction was 4.3% and male adolescents were more addictive than female. Students who were mainly involved with internet chatting or game showed higher internet addiction score. The addiction group and over use group showed higher level of somatization, obsession, interpersonal sensitivity, depression, anxiety, hostility, and paranoia than non-addicted group. Addiction group and over use group used passive coping strategies more frequently in the stressful situation than nonaddicted group. Also, the regression analysis for finding out causal factors that predicts internet addiction showed that emotion relieving strategy were important variable which predict internet addiction. Interpersonal sensitivity and emotion relieving coping strategy was important to predict addiction. This study showed that problematic internet use was closely associated with psychopathology and psychiatric comorbidity. And high interpersonal sensitivity and emotion relieving coping strategy were related with internet addiction in adolescence.

Rat의 복강내에 투여한 5-fluorouracil-polyglycolic acid 제형이 장기에 미치는 영향에 관한 연구

강대영,송규상,최정목,노승무,정경수,오정연,김진향,양준묵,최선웅,이진호,조준식,민병무,김용백,김창식,박근성,김승영,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

For more effective intraperitoneal chemotherapy, the authers made 5-fluorouracil-polyglycolic acid composite disks(FU-PGA disks) with 5-fluorouracil and polyglycolic acid, a biodegradable polymer. We inserted the FU-PGA disk into the peritoneal cavites of Sprague-Dawley male rats, the control and three experimental groups; one FU-PGA disk insert group(300mg/kg), two FU-PGA disk insert group(600mg/kg), and three FU-PGA disk insert group(900mg/kg). The control group received a similar number of PGA disk inserts. A pharmacokinetic study was performed to measure the 5-fluorouracil concentration in the peritoneal fluid, blood, and tissues(liver, kidney and heart) at 24 hours, 72hours and 168 hours after insertion of the FU-PGA disk. Light and electron microscopic studies were done. The results were as follows: 1) The number of white blood cells and platelets decreased after FU-PGA insertion. The degree was proportional to the duration and amounts inserted. The change in the number of red blood cells varied slightly. 2) Light microscopically, slight changes were noted at 168 hours in the 3 disk insert group (900mg/kg). Mild fatty change and hepatocyte degeneration around the central veins of the liver were noted, with vacuolar degeneration in the proximal convoluted tubules of the kidney. 3) Electron microscopically,the liver showed focal increases of lipid droplets in the hepatocytes, and irregular nuclear membrane with focal nucleolar segregation of the fibrillar and granular elements. Also the double membranous structure of the hepatocytes and Kupffer cells was widened with bleb formation. The kidney showed wide separation of the nuclear double membrane in the proximal convoluted tubular cells and mesangial cells, with vacuolation and myelin figure formation in the mitochondria of the proximal convoluted tubular cells, at 72 hours and 168 hours in the 2 to 3 FU-PGA insert groups. The heart showed focal loss of cristae,vacuolation and myelin figure formation in the mitochondria of the 2 to 3 FU-PGA insert groups. In conclusion, despite the large amont of FU-PGA inserted, the histopathological changes in the liver, kidney and heart were slight, and consonant with the very low amount of 5-fluorouracil concentrations detected in the liver, kidney and heart. The above results suggest that the FU-PGA composite can serve as a new device for releasing drugs in a controlled manner and easily targeted to intraperitoneal organs. This device can improve the efficacy of intraperitoneal chemotherapy for gastric cancer.

폐암과 동반되어 나타난 기관기관지병증 골연골형성증 1예

이영진,전현수,박시형,김모세,김현주,이승헌,이영민,이현욱,이현경 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

Tracheobronchopathia osteochondroplastica (TPO) is a rare benign disease of unknown etiology characterized by multiple cartilaginous or bony submucosal nodules, which project into the tracheobronchial lumen. Although some disorders were reported combined with TPO, these seemed to be considered casual. We report a case of TPO that combined with adenocarcinoma of lung. She was 50-year-old non smoking woman presented with chronic cough with right chest pain. Lung mass on right lower lobe was found on chest x-ray, so lung cancer was suspected. Multiple scattered whitish small elevations from trachea to bronchial trees were found on bronchoscopic exam. We mistook these lesions for metastases from lung cancer and biopsies of these lesions were done. Transbronchial biopsy for right lower lobe mass lesion was also done. But biopsies from trachea and bronchus revealed TPO rather than lung cancer. Transbronchial lung biopsy of right lower lobe mass was diagnosed adenocarcinoma of lung. So TPO combined with adenocarcinoma of lung was diagnosed.

농업인 교육 프로그램 분석

김진모,김진군,마상진,전영욱,이진화,주현미 한국농업교육학회 2007 농업교육과 인적자원개발 Vol.39 No.1

이 연구는 농업인을 대상으로 한 교육 프로그램의 내용 및 방법을 살펴봄으로써 향후 농업인 교육을 위한 기초자료를 제공하는 데 목적이 있었다. 농업인 교육프로그램 분석을 위한 개념적 틀은 관련문헌에 대한 고찰과 수집 자료에 대한 귀납적 분석을 통해 개발되었다. 그 결과, 8가지의 기관 유형, 17가지의 프로그램 내용 영역, 5가지의 교육방법, 3가지의 교육인원, 3가지의 교육기간이 도출되었다. 분석대상은 총 173개 기관의 2,483개 프로그램이었다. 이 연구의 주요 결과는 다음과 같다. 첫째, 우리나라의 농업인 교육은 국가기관 및 기술센터 등의 정부기관 주도로 이루어지고 있었다. 둘째, 재배/사육기술, 생활개선 및 농촌건강관리, 정보획득 등의 내용이 주요 교육내용으로 다루어지고 있었다. 셋째, 각 기관 유형별로 비중 있게 다루는 주요 교육내용에 있어서 다소 차이가 있었다. 넷째, 농업인 교육프로그램에서 활용되는 교육방법은 대체적으로 강의에 편중되어 있었다. 다섯째, 교육인원에 있어 중규모와 대규모 인원의 비중이 상대적으로 높았으며, 1 대 1 개별 교육은 전혀 없는 것으로 나타났다. 여섯째, 1일 혹은 3일 이상 이루어지는 교육의 비중이 상대적으로 높았으며, 2일 동안 이루어지는 교육의 비중은 비교적 낮은 편이었다. The purposes of this study were to analyze the farmer education programs in Korea, and to get implications for further program development. The framework for the analysis was developed through extensive literature review and an inductive method. As a result, eight types of organizations for farmer education, seventeen content domains of programs, five instructional methods, three categories of program participant size, and three categories of program period were derived. The subjects of analysis were 2,483 programs of 173 farmer education organizations. The major findings were as follows: 1) Farmer education programs of Korea were led by government agencies such as national organizations and extension agencies. 2) The content domains of cultivating/raising techniques, improvement of life quality and farmer health care, and information acquisition were relatively highly dealt with. 3) Main contents which were dealt with by each type of farmer education organization were differentiated. 4) In terms of instructional method, a lecture had the highest portion in most contents domains. 5) The portion of the middle size and large size of participants was relatively higher than others. And there are no programs which used one by one teaching method. 6) The portion of programs for 1 day or 3days was relatively higher, and the portion of programs for 2 days was lower.