Polystyrene composites containing crosslinked polystyrene-multiwalled carbon nanotube balls

Kwon, Soon-Min,Kim, Hun-Sik,Kim, Don-Young,Yun, Young Soo,Jin, Hyoung-Joon Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of applied polymer science Vol.110 No.6

<P>Crosslinked polystyrene-multiwalled carbon nanotube (PS-MWCNT) balls, which act as conductive microfillers, were prepared by the in situ suspension polymerization of styrene with MWCNTs and divinyl benzene (DVB) as a crosslinking agent. The diameters of the synthesized crosslinked PS-MWCNT balls ranged from 10 to 100 μm and their electrical conductivity was about 7.7 × 10<SUP>−3</SUP> S/cm. The morphology of the crosslinked PS-MWCNT balls was observed by scanning electron microscopy and transmission electron microscopy. The change in the chemical structure of the MWCNTs was confirmed by Raman spectroscopy and Fourier transform infrared spectroscopy. The mechanical and electrical properties of the PS/crosslinked PS-MWCNT ball composites were investigated. It was found that the tensile strength, ultimate strain, Young's modulus, and impact strength of the PS matrix were enhanced by the incorporation of the crosslinked PS-MWCNT balls. In addition, the mechanical properties of the PS/crosslinked PS-MWCNT ball composites were better than those of the PS/pristine MWCNT composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008</P>

장기간 항갑상선제 투여 후 임의 중단 뒤 재복용시 발생한 무과립구증 1 예

김승만;김태영;박수영;배영환;서영경 정은주;김태균;권민정;박정현;이순희 인제대학교 2011 仁濟醫學 Vol.32 No.-

Agranulocytosis, one of the major side effects of antithyroid a gents, probably occurs in less than 0.25% of cases treated with antithyroid agents. It usually occurs within the first several weeks or months after the initiation of therapy, when drug dosage is higher. Most reported cases of agranulocytosis have occurred during the first 3 months of therapy. We describe here a rare case that did not experience the side effect for 6 years of antithyroid agent treatment but presented with agranulocytosis in one month after re-exposure. It suggests that the major side effect such as agranulocytosis can occur in patients who had undergone prior uneventful antithyroid drug therapy.

노화가 인체 중간엽 줄기세포로부터 조골세포로의 증식 및 분화에 미치는 영향

백기현,태현정,오기원,이원영,조정기,권순용,강무일,차봉연,이광우,손호영,강성구,김춘추 대한내분비학회 2003 Endocrinology and metabolism Vol.18 No.3

연구배경: 일반적으로 골다공증과 연관된 위험인자로는 연령, 폐경, 약물, 불충분한 칼슘섭취, 만성질환 및 운동부족 등이 있는데, 특히 노화가 진행할수록 골밀도가 감소하는 것은 잘 알려져 있다. 노화와 관련하여 진행되는 골소실은 조골세포 및 전구조골세포의 기능적 결핍에 의한 골형성의 감소가 주요한 요인으로 여겨지고 있다. 그 동안 연령이 조골모 세포의 양과 조골모 세포로부터 성숙조골세포로의 분화 및 증식에 미치는 영향에 대한 일부 보고들이 있었으나 아직 일치된 견해는 없는 형편이다. 방법: 다양한 연령의 사람으로부터 골수를 채취, 중간엽 줄기세포가 포함된 단핵세포를 분리한 후 조골세포로 분화하기 좋은 조건하에서 배양하였다. 대상군은다시 젊은군과 노령군으로 구분하여 다양한 변수를 비교 분석하였다. 일차배양에서는 CFU-F를 계수하여 골수내 중간엽 줄기세포의 수를 추산하였고, 칼슘측정을 통하여 기질의 무기화 정도를 비교하였다. 계대배양후 이차배양에서는 시기별로 알카리성 포스파타제 활성도를 측정하고 오스테오칼신 mRNA의 발현을 관찰하여 젊은군과 노령군 사이의 증식능 차이를 비교하였다. 또한 이차배양 시기별로 MTT 측정을 하여 양군간에 증식능 차이가 있는지 알아보았다. 결과: 1. 일차배양 15일째에 평균 CFU-F의 수는 젊은군에서 유의하게 많았다(젊은군 148.3±28.9, 노령군 54.3±9.1, p=0.02). CFU-F의 평균면적은 젊은군에서 넓은 경향을 보였으나 통계적으로 유의하지는 않았다. 2. 일차배양 17일 경과 후 양군간에 기질 칼슘 침착정도는 유의한 차이를 보이지 않았다(젊은군 103.6±50.6, 노령군: 114.0±56.5, p=NS). 3. 이차배양 10일째에 젊은군에서 알카리성 포스파타제 활성도가 고령군에 비해 유의하게 높았다(젊은군: 935.5±115.0 U/mg, 노령군: 578.4±115.7U/mg,p.0.05). 고령군에서는 시간 경과에 따른 변화가 미약했으며 전반적으로 알카리성 포스파타제의 활성도가 젊은군에 비해 낮았다. 4. 이차배양도중 오스테오칼신 mRNA의 발현은 배양시기별로 젊은군에 비해 고령군에서 더 낮은 경향을 관찰할 수 있었다. 5. 이차배양 10일과 15일에 젊은군에서 노령군보다세포증식이 유의하게 증가된 양상을 보였다(10앓 젊은군 0.73±0.05, 노령군 0.58±0.04, p=0.05, 15일; 젊은군 0.80±0.05, 노령군 0.70±0.03, p=0.05).결론: 이상의 연구에서 저자들은 노령군에서 젊은군보다 골수 내 중간엽줄기세포의 수가 적고, 노령군에서 유래한 전구조골세포의 성숙조골세포로의 증식 및 분화가 젊은군 보다 감소해 있는 것을 관찰할 수 있었다. Background: Osteoblasts originate from osteoprogenitor cells in bone marrow stroma, termed mesenchymal stem cells (MSCs) or bone marrow stromal cells. Each MSC forms colonies (colony forming units-fibroblasts [CFL-Fs]) when cultured ex vivo. There are some reports about the age-related changes of the number and osteogenic potential of osteoprogenitor cells, but any relationship has not been clearly established in humans. In this study, we counted MSCs using CFU-Fs count and examined the proliferative capacity and differentiation potential of osteoprogenitor cells. Finally, we analyzed how these parameters varied with donor age. Methods: Bone marrow was obtained from the iliac crest of young (n=6, 27.2±8.6 years old) and old (n= 10, 57.4k6.7 years old) healthy donors. Mononuclear cells, including MSCs, were isolated and cultured in osteogenic medium. In primary culture, we compared the colony-forming efficiency of MSCs between the two groups and determined the matrix calcification. When primary culture showed near confluence, the cells were subcultured. Alkaline phosphatase activity, osteocalcin expression by RT-PCR and proliferative potential by MTT assay were examined by the time course of secondary culture. Results: At the 15th day of primary culture, the mean number of CFU-Fs was significantly higher in the younger donors (young: 148.3±28.9, old: 54.3±9.1, p=0.02) and the mean size of CFL-Fs was also larger in the younger donors than the older donors. However, matrix calcification was not different between the two groups (young: 103.6±50.6, old: 114.0±56.5, p=NS). In secondary culture, alkaline phosphatase activities were significantly lower in the older donors. The younger donors showed peak alkaline phosphatase activity at day 10, while the older donors didn't showed a remarkable peak (young: 935.5±115.OU/mg, old: 578.4±115.7U/mg, p<0.05). Total cell number as a proliferative index increased progressively during the secondary culture and a significantly greater cell number was noted in the younger donors. Osteocalcin expression was generally upregulated in the younger donors, but this was not statistically significant. Conclusion: Our study shows that the number of osteoprogenitor cells is decreased during aging and that the proliferative capacity and differentiation potential of osteoprogenitor cells seem to be reduced during aging (J Kor SOC Endocrinol 18:296-305, 2003).

이온 플레이팅법으로 제조한 TiN 박막의 미세구조

권순영,김민호,이해석,손창헌,김규호 嶺南大學校 工業技術硏究所 1997 工業技術硏究所論文集 Vol.25 No.1

Hard coating의 일종인 TiN 피막을 PVD 법으로 제조할 경우, 이온 충돌 양상을 조절할 수 있는 기판 Bias와 질소 분압 등이 미세 구조와 피막 특성에 많은 영향을 미치는 것으로 알려지고 있다. 본 실험에서는 Ion plating에 의한 TiN 피막 제조에서 기판 바이어스 전압과 질소 분압을 변화시키면서 TiN 피막을 제조하고, 미세 구조를 조사하였다. 공정 변수에 관계없이 얻어진 모든 피막은 δ-TiN 단일상이었다. 질소 분압이 높아짐에 따라 우선배향은 (111)면에서 (200)면으로 바뀌었으며, (111)회절상과 (222) 회절상의 반가폭의 비는 감소하였다. 그리고 결정의 크기는 감소하는 거동을 보였으며 피막의 격자 상수는 증가하는 경향을 보였다. 기판 바이어스 변화에 대해서는 전압이 증가함에 따라 (111) 회절상의 반가폭은 -100V 가지 증가하다 그 이상에서는 다시 감소하였으며, 그 때 결정이 크기는 증가하는 경향을 보였다. 피막의 격자 상수는 기판 바이어스가 증가함에 따라 150V까지 증가하다 그 이상에서는 다시 감소하였다. The action of ionized particles has to be controlled properly in ion plating method, because the action of ionized particles has an effect on the microstructure of the thin film. In this pointview, we investigated microstructure of TiN thin film that was deposited with variables of N₂partial pressure is increased, the prefered orientation was changed(1110 plane to (200) plane, the ratio of FWHM of (222) to FWHM of (111)was decreased, grain size was decrease and lattice parameter was increased. As bias voltage was increased, the FWHM of (111) peak was increased to-100V, and then decreased with the grain size was increased. Lattice parameter of film was increased to-150V, and then decreased

잡음환경에서의 음성인식을 위한 전처리의 성능비교

권영옥,김형순 釜山工業大學校 1995 論文集 Vol.37 No.-

One of the ultimate purpose in speech recognition is to recognize all of the arbitrary natural-sentences spoken by arbitrary speaker under any adverse environments. We review the theoretical and experimental foundations of the method, discuss the relationship with auditory perception, and extend to combination of additive noise and convolutional noise. This paper describes that performance comparision of the preprocessing schemes are applied to speech recognition in the adverse environments. Also some experiments of speech recognition are performed for department name of twenty-two that are pronounced one times by fifty Korean adults. The results show an application of the RASTA technique to speech enhancement.

콘크리트 덧씌우기 전후 비교조사에 따른 덧씌우기공법의 지지력 및 하중전달 특성 연구

권순민,서영찬 漢陽大學校 工學技術硏究所 1997 工學技術論文集 Vol.6 No.1

A 290m 2-lane experimental concrete overlay was constructed in 88 Express Highway to investigate it's feasibility in Korea. The test section consists of both bonded and unbonded type overlays. Pavement condition of the existing slab was surveyed before overlay, and construction feasibility of concrete overlay was checked during construction. After overlay, delamination, crack, deflection(using FWD), and load transfer at various temperature conditions have been measured periodically. Findings from the study can be summarized as follows. (1) The overlays performed successfully during at least 1 year after construction, (2) Overlay reduced deflection by 47% in bonded overlay section and by 57% in unbonded overlay section, (3) Unbonded overlay showed better load transfer than bonded overlay, (4) Joints transfer dowel bar showed better load transfer than those without dowel bar, and (5) Load transfer efficiency varied with temperature conditions.

벗김전압전류법을 이용한 미량의 루테늄의 정량

權英順,金素眞 카톨릭대학교 성심교정 1995 論文集 Vol.2 No.-

루테늄을 정량하기 위하여 벗김전압전류법을 사용하였다. 히드라진-초산용액에서 촉매효과와 측적방법을 결합하여 실험한 검출한계는 7.0x10-9M이다. 이때의 조건은 초산완충용액 0.01M, 히드라진0.01M, 축적전위 -0.76V, 축적시간 2.0분이다. Stripping voltammetric for the determination of Ruthenium is described. By the use of combined catalytic effects and accumulation in hydragine-acetate solution, the limit of detection is 7.0x10-9M. Optimized condition are 0.01M acetate buffer solution containing 0.01 M hydragine, an accumulation potential of -0.76V(vs. As/AgCl) and accumulation time of 2.0 min.

5-Phenyl-4,5-dihydro-1H-benzazepin-2 one의 합성

권순경,박영남 德成女子大學校 2003 德成女大論文集 Vol.32 No.-

The first of benzodiazepines was chlordiazepoxide, which was marketed as tranquilizer under the trade name Librium. Now benzodiazepine derivatives are prescribed for insomnia and muscle relaxants as well as to treat anxiety. As benzodiazepines used widely, drug abuse becomes a serious social problem because of psychological and physical dependence and over deaths. It is necessary to develop the in vitro diagnostic reagents for the detection of small amount of abused drugs in urines. Because accuracy and convenience for point of care testing systems are indispensable, immunological determinations are fit for our requirements, which react with specific drug antigens and are able to detect small amount of drugs in urine. A benzazepinone derivative(4), which will be used as a component of the reagents for detecting benzodiazepine drugs or their metabolite in urine, was synthesized from 5-phenyltetrahydrofuran-2-one(1) as a key intermediate.

PbS-Ag₂S 막전극의 특성과 응용

권영순,심옥임 聖心女子大學校 1983 論文集 Vol.15 No.-

Pbs-Ag₂S 막전극은 ??농도 범위의 ??용액에서 Nernst 기울기에 잘 맞는다. 이 전극의 감응은 ?? 순서로 감소한다. 이 전극은 이 전극에 감응하는 각각의 금속이온과, 그리고 ?? 같은 금속 혼합물을 EDTA로서 착화적정하는데에 이용될 수 있다. 이 전극은 ?? 같은 단일음이온과 음이온혼합물을 ?? 표준용액으로 전위차적정할 때에도 이용될 수 있다. 50% methanol 용매를 쓰면 더 좋은 전위급변을 얻을 수 있다. The PbS-Ag₂S memberane electrode has showed a linear potential response to the activities of lead ion in the concentration range from ??to ?? with Nernstian Slope. The response of this electrode is decreased in the order ?? This membrane electrode could be used in the chelometric titrations of each responsing metal ion and mixture ions such as ??with EDTA. This electrode could be also used in the potentiometric titrations of a single anion, such as ?? and anion mixture with the standard solution of lead nitrate. Good potential break was obtained by using 50% methanol solvent.

바나듐과 크롬의 쿠페론 착물의 전기화학적 행동의 차이

권영순,이상미,정미영,박소영 가톨릭대학교 자연과학연구소 2004 자연과학논문집 Vol.25 No.-

바나듐과 크롬의 쿠페론 착물의 전기화학적 행동을 아세트산 완충용액(pH 5.0)과 붕산염 완충용액(pH 9.5)에서 조사해 본 결과 크롬-쿠페론 착물의 환원봉우리전위(E_(ct)^(p))가 쿠페론의 봉우리전위(E₁^(p))보다 작다 (E_(ct)^(P) < E₁^(P)). 붕산염 완충용액에서 크롬-쿠페론계의 전도된 봉우리가 크게 나타나는 것은 E_(ct)^(P)와 E₁^(P)의 차이가 큰 때문인 것으로 생각된다 (ΔE = 0.40V). When the peak potentials of V-cupferron and Cr-cupferron complex compare at both buffer solution(pH 5.0 and pH 9.5), the peak potential of Cr-cupferron(E_(ct)^(P)) is smaller the peak potential of cupferron (E₁^(P)) at both buffer solution (E_(ct)^(p)) < E₁^(p)). The appearance of larger inverted peak of Cr-cupferron in borate buffer solution results from large difference of E_(ct)^(p) and E₁^(p) (ΔE=0.40 V).