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      • 콘크리트의 壓縮强度에 미치는 굵은 골재 크기의 영향에 관한 基礎的 硏究

        윤석천,박서규,남재현,김무한 충남대학교 공업교육연구소 1985 論文集 Vol.8 No.1

        The purpose of this study is to research an effect of aggregate size on the compressive strength of concrete. Tests were, therefore, made in sixteen classes of concrete : maximum aggregate sizes of 5, 10, 20, 30^mm with water cement rations of 40% and 60% and with AEA°cement rations of 0.00% and 0.03% for each maximum aggregate size. The results of this experiment are showing the fellowing tendency. 1. Generally, with the range of this experiment program, the smaller maximum aggregate size becomes, the higher the compressive strength of concrete gets. 2. The decreasing tate of the compressive strength of concrete gets higher in lean mix concrete than in rich mix concrete at each age. 3. The compressive strength of concrete is developed faster with not only the increase of maximum aggregate size but also the decrease of water cement ratio. And it shows that the rate of the compressive strength development is higher in AE concrete in spite of water cement ratio.

      • Alnico 8 型 硬質磁性材料의 磁氣的 性質에 미치는 添加元素의 影響

        徐圓根,金澤基,金潤培 忠南大學校 産業技術硏究所 1986 산업기술연구논문집 Vol.1 No.1

        In order to study the alloying elements effects on the magnetic properties in Alnico 8 (Fe-35Co-14Ni-7Al-5Ti-3Cu) permanent magnet alloy, some Alnico 8-type alloys which are different in composition of Ni, Cu, Ti and Al were prepared by induction melting. They were thermomagnetically treated at 740℃ - 840℃ for 3-15 min and then aged at 600℃ for 15hours. The magnetic properties and the optimum thermomagnetic treatment condition were investigated. The results were as follows ; 1) The region of the high temperature α phase, the zone of the solution treatment, is extended by Al and Ti, but that is reduced by Ni and Cu. 2) In the composition range of 10-14 wt.% of Ni, the coercive force decreases greatly with decreasing the Ni content with little change of the residual magnetization and the squareness of demagnetization curve. The optimum thermomagnetic treatment condition appeared at high temperature and short time with decreasing the Ni content. 3) In the composition range of 1-3wt.% of Cu, the coercive force decreases greatly with decreasing the Cu content, but the residual magnetization shows increasing tendency with decreasing the Cu content. The optimum thermomagnetic treatment condition appeared at low temperature and long time with decreasing the Cu content. 4) In the composition range of 5-8wt.% of Ti, the coercive force increases with increasing the Ti content, but the residual magnetization decreases with increasing Ti content. The optimum thermomagnetic treatment temperature was not dependent on the Ti content, but the optimum thermomagnetic treatment time appeared at long time with increasing the Ti content.

      • 화상에 의한 간상해에 Anti-prostaglandin이 미치는 영향

        김용송,임정교,손윤경,서인수,손태중 慶北大學校 醫科大學 1991 慶北醫大誌 Vol.32 No.1

        저자는 anti-prostaglandin의 화상독에 의한 간상해에 미치는 영향에 관하여 알아보고자 Sprague-Dawley계 흰쥐 수컷의 체표 30%에 3도 화상을 일으키고 생리식염수와 anti-prostaglandin제제인 flurbiprofen을 투여한 후 각각 5일과 10일 후 도살하여 간의 변화를 관찰하였으며 성적은 다음과 같다. 생리식염수를 투여한 실험군에서는 화상 5일 후 간세포에 mitochondria의 상해와 ER의 확장이 있었고 유동내에는 호중구 등 염증세포의 침윤이 있었다. 화상 10일 후에는 상기한 mitochondria의 상해가 거의 수복되고 ER의 확장도 감소되었으며 유동내의 염증세포도 거의 보이지 않았다. flurbiprofen을 투여한 실험군에서는 화상 5일후 mitochondria의 상해와 ER의 확장이 관찰되었으며 이는 화상 10일 후 까지 지속되었다. 이상의 성적으로 보아 중증화상후에 간은 화상독에 의하여 간세포 mitochondria의 상해를 주로하는 손상을 받게되나 이는 시간이 지나면 수복 가능한 가역적인 상해라 보아진다. 또한 anti-prostaglandin제제는 화상독에 의한 간세포상해에 거의 영향을 미치지 못할 것으로 생각된다. An ultrastructural study was carried out to investigate the effects of burn toxin to liver. Thermal burns wee tried on the skin of Sprague-Dawley rats with severity of 30% and 3rd degree. Flurbiprofen (a kind of anti-prostaglandin) and normal saline was administered every day after burn. The animals were sacrificed at 5 days and 10 days after burns and the livers were extracted for electron microscopic observation. The liver cells of saline intake groups at 5 days after burns were characterized by generalized mitochondrial injury, such as swelling, loss of cristae and membrase destruction. Dilatation of ER and lysosomal increase are also noted. The sinusoid revealed neutrophilic infiltration. At 10 days after burns the liver cells demonstrated nearly normal structure without mitochondrial injury. Mild dilatation of ER was seen. The flurbiprofen intake groups revealed that mitochondrial swelling, loss of critae and destruction of mitochondrial membrane with dilatation of ER and lysosomal increase at 5 days after burns. These features were continued to 10 days after burns. According to these results, it would be concluded that the effects of burn toxin to liver is characterized by mitochondrial injury and it is reversible change. And the anti-prostaglandin drugs may not be effective to inhibit the progressive injury induced by burn toxin.

      • KCI등재

        사망 진단서(시체 검안서) 작성의 문제점

        김규석,임용수,이중의,서길준,윤여규,어은경,염석란,정연권,이윤성 대한응급의학회 2000 대한응급의학회지 Vol.11 No.4

        Background: This study was conducted to analyze the current problems in completing death certificates and to identify the correct method for completing death certificates Methods: We reviewed 262 death certificates in three hospitals from March 1 to April 30, 2000, and 119 death certificates in one hospital from March 1 to 31, 2000. We identified major and minor errors and analyzed and compared them retrospectively. Results: A total of 381 death certificates were reviewed: 59 in Seoul National University Hospital,101 in Ewha Woman's University Hospital, and 102 in Gachon Medical College Hospital, which has no education program for completing death certificates in postgraduate training, and 119 in Samsung Medical Center which has an education program for completing death certificates. 358 certificates(94.0%) had at least one error. There were only 23 death certificates(6.0%) without an error. In 182 cases(47.8%), there was one major error. In 321 death certificates(84.3%), there were more than two errors. A comparison of Samsung Medical Center with the other hospitals showed that the number of total errors was statistically different(p=0.001). Conclusion: There were few death certificates without an error in this study. In a hospital which has postgraduate training in completing death certificates, there are fewer errors than in other hospitals which have no training course. Emergency physicians actually certify many deaths, so they must know the correct method of completing death certificates for statistics on morbidity and mortality.

      • KCI등재후보
      • 방향족 화합물의 할로 메칠화 반응

        박정서,김신종,백운필,이현주,송윤석,장정민 明知大學校 自然科學硏究所 1997 자연과학논문집 Vol.15 No.-

        Biphenyl의 para position에 methylene group을 도입 시키는 방법으로 paraformaldehyde와 dimethylamine을 반응시켜 Mannich Base인 (1,1'-biphenyl-4,4'-dimethyl)-dimethli amine을 합성해 보았으나, 전혀 반응이 진행되지 않았다. 즉 , Biphenyl에 강한 activating group이 없으므로 Mannich Base을 사용한 방법은 효과적이 못된다. 따라서, 다른 방법으로 biphenyl에 bromomethylation을 진행 시켜서, 두 개의 methylene group을 도입시켰다. Bromomethylation은 다음과 같이 사용하는 시약 및 실험 방법 등을 고려하여 3가지 방법으로 시도 하였다. 1)1,3,5-trioxane + HBr in AcOH + paraformaldehyde 사용법, 2)Hbr in AcOH + paraformaldehyde 사용법, 3) NaBr + H₂SO₄+paraformaldehyde 사용법, 이상의 3가지 방법 중에서 NaBr+ H₂SO₄+ paraformaldehyde 사용법이 가장 좋은 결과를 얻었다. 이러한 system에서 반응을 진행시킨 결과 69% 의 높은 수율 (87%의 purity)로 4,4'-dibromomethylbiphenyl 합성에 성공할 수 있었다. The synthetic method for the induction of methylene group on the para position of arenes is of importance. Since the weak activation effect of phenyl group on the electrophilic substitution reaction, the induction of methylene group by way of Mannich base using paraformaldehyde and dimethylamine was unsuccessful. It was found that halomethylation of byphenyl is only the way for the preparation of di-p-methylenebiphenyl. Especially, bromomethylation was turn out to be more reliable synthetic method than chloromethylation. Herein, we developed 3 protocols for the synthesis of 4,4'-dibromomethylbiphenyl. In addition, the best result was obtained using NaBr + H₂SO₄paraformaldehyde protocol in 69% yield.

      • Heparin이 망내계세포에 미치는 영향에 관한 초미형태학적 연구

        이동철,김중길,임정교,손윤경,서인수,손태중 慶北大學校 醫科大學 1991 慶北醫大誌 Vol.32 No.3

        저자들은 heparin 투여후 세망내피계의 초미형태학적 변화를 관찰하기 위해 Sprague-Dawley계 숫쥐에 heparin과 endotoxin을 투여한 후 비장을 채취하여 실험에 이용하였다. 실험군은 heparin 전처치군과 heparin 후처치군으로 나누었으며 비교군으로 heparin 단독투여군과 endotoxin 단독투여군을 설정하여 각각을 투약후 비장을 채취하여 광학현미경 및 전자현미경적 검색을 실시하였다. 실험결과를 요약하면 heparin 단독투여군은 대식세포, 형질세포양 림프아구 및 다핵백혈구가 증가되었고, 대식세포의 탐식능도 항진되었다. 그러나 대식세포자체의 소기관 발달은 현저하지 않았다. Endotoxin 단독투여군은 시간이 갈수록 대식세포의 탐식능이 저하되고, 파괴가 증가되어 수가 감소하였다. 미소혈전이 자주 관찰되었으며 기타세포들의 파괴가 관찰되었다. Heparin 전처치 및 후처치군은 공히 endotoxin군에 비해 대식세포 탐식능이 증가되었다. 이상의 성적으로 보아 heparin의 망내세포에 대한 영향은 주로 대식세포의 탐식능과 수의 증가로 생각되며 이는 정상 및 병적상태 모두에서 일어난다고 생각된다. 또한 ET 투여 전후 heparin을 투여한 실험군에서 공히 대식세포 탐식능이 증가되었으므로 이는 ET shock 후 조직손상으로 분비되는 세망내피계 저하물질에 대해 heparin이 길항작용을 할 것으로 생각된다. 또한 heparin의 대식세포 탐식능항진에 대한 효과는 세포의 직접적인 자극이라기 보다는 탐식과정중 특히 oposonization에 효과를 미칠 것으로 생각된다. The authors studied an ultrastructural changes of reticuloendothelial system after administration of heparin. Male Sprague-Dawley rats were examined after administration of heparin and endotoxin. The experimental groups were divided into heparin pretreated groups and heparin posttreated groups. The control groups were divided into heparin-only groups and endotoxin-only groups. Each animals were sacrificed and spleens were extirpated and examined by light and electron microscopy. The results obtained were summarized as follows: Heparin-only groups showed proliferation of macrophages, lymphocytes and neutrophils. The phagocytic activity of marcophage is enhanced. The cytoplamic organellar change is not remarkable except increase of secondary lysosomes. Endotoxin-only groups showed decrease of phagocytic cells. The phagocytic activity is also depressed. Destruction of macrophages and other cells are noted. Microthrombi are frequently seen. Both heparin pretreated and heparin posttreated groups revealed relative enhancement of phagocytic activity compaired to endotoxin-only groups. From the result of the experimental study, it appears that the effect of heparin on the reticuloendothelial system is enhancement of phagocytic activity of macrophages both in the coditions of normal and pathologic one. And it also suggests that heparin may act as an antagonizing factor to the reticuloendothelial depressing agent that may be derived from injured organ of endotoxin shock. And the effect of heparin to the phagocytic activity of macrophage may be related to the process of phagocytosis such as opsonization or to the direct cellular stimulation.

      • KCI등재

        뇨(尿)중 3-Methylhistidine 함량의 측정과 이용

        정수현,서형주,김윤숙,이효구,강덕호 한국식품영양학회 1996 韓國食品營養學會誌 Vol.9 No.2

        기존의 방법을 일부 수정하여 뇨중 3-methylhistidine을 분석하였다. 뇨중 3-methylhistidine을 fluorescamine 유도체화하여 HPLC에 주입하고 C_18 column과 10 mM acetonitrile/sodium phosphate buffer(pH 7.5)로 분리·용출시켜 형광검출기로 측정하였다. 3-methylhistidine의 체류시간은 7분 이내이었으며, histidine과의 분리상태도 서로 간섭함이 없이 양호하였다. 뇨에 3-methylhistidine을 첨가하고 이를 분석하였을 때의 회수율은 93∼106%로 높은 수준이었다. 체육학과 남학생중 웨이트 트레이닝 단련자와 비단련자를 대상으로 조사한 단기간의 웨이트 트레이닝에 따른 뇨중 3-methylhistidine 함량의 변화는 두 집단 모두 웨이트 트레이닝후의 3-methylhistidine 분비량이 유의하게 증가하였다. A modified method is given for the precolumn derivatization and subsequent high-pressure liquid chromatographic seperation of 3-methylhistidine from urine. The elution contained isocratic solution with acetonirile and 10 mM sodium phosphate(pH 7.5) requires less than 7 min. The recoveries of 3-methylhistidine from urine control were 93% to 106%. 3-Methylhistidine determinations were performed on urine samples from volunteers who were both male trained and non-trained physical undergraduates. As the result, urinary 3-methylhistidine content of volunteers increased significantly after weight training.

      • 세포질내 정자주입법(ICSI)에 있어서 정자흡입 및 난자내 주입방법에 관한 연구

        이택후,김항진,송건호,김대근,전상식,박윤규,서태광,전병균,류은경,이은숙,문진수,김광철 경북대학교 의학연구소 2000 경북대학교병원의학연구소논문집 Vol.4 No.1

        Study on Method of Sperm Aspiration and Injection into an Oocyte in Intracytoplasmic Sperm Injection(ICSI) Immobilization of spermatozoa prior to intracytoplasmic sperm iniection(ICSI) sometimes results in crooked tail and this makes it difficult to aspirate sperm into an injection pipette tail first. Head-first sperm aspiration into an injection pipette avoid this problem due to the bigger size of the sperm head. The effect of head or tail-first sperm injection into an oocyte on fertilization cleavage, percentage of grade I embryos and development to blastocyst stage in ICSI program has been studied. A single living immobilized spermatozoa from oligoasthenozoospermic patient was injected into an oocyte head-first or tail-first according to the treatment. Eighteen hours after microinjection, oocytes ware inspected for survival and fertilization Fertilized oocytes with two pronuclei were cultured in 30μl drop of mHTF supplemented with 10% heat-inactivated follicular fluid(FF) at 37℃. On day 2. embryo transfer was performed with cleaved embryos. The remaining 2-8 cell stage embryos were co-cultured with BRL cells in mHTF + 10% FF for 72 hours and the developmental stage was observed. The data were analyzed by Analysis of Variance. A total of 164 oocytes from 36 cycles were assigned to earth treatment and ICSI was performed(88 head-first, tail-first). The rates of normal fertilization were 81.8% and 76.3% for head-first and tail-first, respectively. Of the fertilized oocytes, the percentage of cleaved embryos and the percentage of grade 1 embryo among cleaved embryos were 88.9% and 68.8%, 93.1% and 74.1% for head-first and tail-first, respectively. Of the 2-8 cell embryos cultured, 44.4%(16/36) and 50.0%(10/20) for head first and tail first, respectively developed to blastocyst stage. There were no differences in fertilization, cleavage, rates of grade 1 embryos, and development to blastocyst stage. In conclusion, head-first or tail-first sperm injection into an oocyte in ICSI program does not affect fertilization and subsequent embryo development to blastocyst stage in vitro.

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