• Title/Summary/Keyword: 박정현

Search Result 603, Processing Time 0.022 seconds

특집 - 전문의가 바라본 2008년 당뇨병 치료 변화 패턴

  • Park, Jeong-Hyeon
    • The Monthly Diabetes
    • /
    • s.217
    • /
    • pp.27-31
    • /
    • 2007
  • 의학은 항상 변화하고 발전하는 학문이다. 특히 최근 임상의 학은 눈부시게 빠른 속도로 발전해가고 있다. 당뇨병의 치료 분야는 임상의학의 모든 분야를 통틀어 가장 빠르게 발전하고 있는 분야의 하나로 해가 갈수록 이전과는 다른 내용의 과학적 정보들 및 진료지침들이 만들어지고 있다. 하지만 이러한 발전에도 불구하고 아직도 우리가 당뇨병의 병태생리에 대해 알고 있는 지식과 당뇨병을 치료하기 위해 가지고 있는 기술은 1921년 인슐린이 발견된 이래로 크게 진보된 것은 없다고 생각한다. 아직도 많이 불완전한 치료 방법들만을 너무 맹신하고 당뇨병의 보다 근본적인 병태생리가 되는 생활습관의 왜곡에 대해 보다 적극적으로 개입하지 않는 것은 크게 잘못된 것이다. 2008년에는 당뇨병을 앓고 있는 모든 환자분들과 당뇨병 치료에 관련된 모든 의학계의 분들이 같이 노력해서 잘못된 관행과 습관 및 제도 등을 개선하고, 약물에만 의존할 것이 아니라 잘못된 생활 습관을 제대로 교정하려는 노력도 함께 기울였으면 한다.

  • PDF

Screening of Deoxynivalenol Producing Strains from Agricultural Products by Immunoanalytical Method (면역분석기법에 의한 농산물에서의 Deoxynivalenol생성균 검색)

  • 강성조;오상석;박정현;김형갑;장덕화
    • Journal of Environmental Health Sciences
    • /
    • v.27 no.4
    • /
    • pp.35-40
    • /
    • 2001
  • In order to evaluate the safety of agricultural products in Korea, we carried out work by screening of Fusarium species. which can produce deoxinivalenol(DON) from agricultural products in Western Gyeongnam, Korea. From 215 samples of soil agricultural products, 129 strains of Fusarium species were obtained. The production of DON was verified by thin layer chromatography(TLC) As the results of TLC, 25 strains were identified as DON producing strain. But only 10 strains were identified as DON producing strains by enzyme-linked immunosorbent assay (ELISA). The maximum DON producing strain No.41 was isolated from corn. In conclusion. the above results indicate that DON producing fungi contaminated agricultural products in Korea. Therefore further studies are required to accumulate more detailed data about the contamination of DON in various agricultural products.

  • PDF

A Study on the Si-SiC Composites Fabricated by Pressureless Powder Packing Forming Method (무가압 분말 충전 성형법에 의해 제조된 Si-SiC 복합체에 관한 연구)

  • 박정현;임은택;성재석;최헌진;이준석
    • Journal of the Korean Ceramic Society
    • /
    • v.32 no.6
    • /
    • pp.710-718
    • /
    • 1995
  • The new forming method, Pressureless Powder Packing Forming Method was applied to the manufacturing of reaction sintered SiC. After the experiments of vibratory powder packing and binder infiltration, the abrasive SiC powder of which mean size is 45${\mu}{\textrm}{m}$ was selected to this forming method. Uniform green bodies with porosity of 45% and narrow pore size distribution could be formed by this new forming method. Also, complex or varied cross-sectional shapes could be easily manufactured through the silicone rubber mould used in this forming method. Maximum 15 wt% amorphous carbon was penetrated into green body by multi impregnation-carbonization cycles. And reaction-bonded SiC was manufactured by infiltration of SiC-carbon shaped bodies with liquid silicon.

  • PDF

The Fabrication and Characteristics of Porous Alumina Ceramics by Pressureless Powder Packing Forming Method : I . Alumina (무가압분말충전성형법에 의한 다공성 세라믹스의 제조 및 특성 : I. 알루미나)

  • 박정현;황명익;김동희;최환욱;김용남
    • Journal of the Korean Ceramic Society
    • /
    • v.36 no.6
    • /
    • pp.662-670
    • /
    • 1999
  • Porous alumina was fabricated from pressureless powder packing forming method using powders granulated by spray drying. It was investigated the pore size distribution of fabricated porous alumina. The results of microstructural observation showed that intraganular pore size and intragranular pore size. At 1700$^{\circ}C$ there were no intragranular pores but it showed homogeneous distribution of intergranular pore size. The bending strength and shrinkage increased as porosity decreased. In case of thermal shock resistance sudden decrease of bending strength to $\Delta$T was not shown because intergranular large pore prevented sudden crack propagation.

  • PDF

The Fabrication and Characteristics of Porous Ceramics by Pressureless Powder Packing Forming Method ; II, Mullite & Cordierite (무가압분말 충전성형법에 의한 다공성 세라믹스의 제조 및 특성 : II. 뮬라이트 & 코디어라이트)

  • 박정현;황명익;김동희;최환욱;김용남
    • Journal of the Korean Ceramic Society
    • /
    • v.36 no.6
    • /
    • pp.671-678
    • /
    • 1999
  • Porous ceramics were fabricated from pressureless powder packing forming method using mullite and cordierite powders granulate by spray drying. The bending strength and shrinkage of porous ceramics were increased and their porosity were decreased with increasing temperature. It showed homogeneous distribution of 2$\mu\textrm{m}$ intergranular pores of mullite at 1400$^{\circ}C$, 2.5$\mu\textrm{m}$ intergranular pores of cordierite at 1300$^{\circ}C$ respedtively. Above that temperature intragranular particles were sintered and sintering by intergranular necking was extremely proceeded. In the test of thermal shock resistance sudden decrease of bending strength to $\Delta$T was not shown because intergranular large pore prevented sudden crack propagation.

  • PDF

A Study on the Fabrication of Sialon Powder through the Thermit Ignition (Al 분말의 점화열을 이용한 Sialon 분말 제조에 관한 연구)

  • 박정현;전병세;이은창
    • Journal of the Korean Ceramic Society
    • /
    • v.23 no.2
    • /
    • pp.1-6
    • /
    • 1986
  • The mixture of (opalit+Al) powder was ignited by electric shock for the preparation of sialon powder by changin the contents of Al. The formation reaction of sialon was investigated by heating the specimens of ignited mixture (opalit+Al) in nitrogen atmosphere at various temperature. The phases existing inthe specimens nitrided between 1400 and 1$600^{\circ}C$ were found $\beta$-sialon 15R-sia-lon $Al_2O_3$ and AlN but the mixture $\beta$-sialon and 15R-sialon was finally acquired by heating the ignited mixture of (Al 50%+opalit) at 175$0^{\circ}C$ for 3hours in nitrogen atmosphere.

  • PDF

Mullitization of Kyanite-Al Mixture (Kyanite-Al 혼합물의 Mullite화 반응)

  • 박정현;배원태
    • Journal of the Korean Ceramic Society
    • /
    • v.23 no.2
    • /
    • pp.7-12
    • /
    • 1986
  • As the other silicate minerals such as kaolinite and pyrophyllite kyanite ($Al_2O_3$.$SiO_2$) is transformed to mullite and free silica or glassy phase at high temperature. Therefore $Al_2O_3$ is commonly added to kyanite in order to increase the mullite-yield. In case of $Al_2O_3$-addition mullite-yield depends on the reactivity of added $Al_2O_3$ with free silica which occurs from transformation of kyanite or exists as accessory minerals. It is well known that addition of activated $Al_2O_3$Al powder is added to kyanite to utilize the aluminothermal reac-tion of Al powder in reaction of mullite-formation.

  • PDF

Sinterability and Stability of Tetragonal Zirconia Polycrystals Co-Stabilized by CeO2 and Other Oxides (CeO2와 각종 산화물에 의해 동시 안정화한 정방전 ZrO2 다결정체의 소결성과 안정성)

  • 박정현;문성환
    • Journal of the Korean Ceramic Society
    • /
    • v.28 no.7
    • /
    • pp.541-548
    • /
    • 1991
  • Sinterability and stability of TZP ceramics co-stabilized by 12 mol% CeO2 and divalent or trivalent oxides less than 1 mol% were investigated. Divalent and trivalent oxides increased stability of tetragonal ZrO2. 100% tetragonal ZrO2 phase was obtained by doping 12 mol% CeO2 and 0.2 mol% CaO and MgO respectively when sintering was carried out at 1500$^{\circ}C$ for 2 hours. Divalent and trivalent oxides improved sinterability and inhibit grain growth of ZrO2. And it was found that CaO was the most effective sintering aid and grain growth inhibitor for ZrO2 in this study. Incorporation of divalent and trivalent oxides into 12Ce-TZP increased the strength of 12Ce-TZP and particulary 12Ce, 0.4Ca-TZP exhibited a flexural strength of about twofold greater than 12Ce-TZP.

  • PDF

Study on the Reaction between $BaTiO_3$ Ceramics and Oxide Setters ($BaTiO_3$ 세라믹스와 Oxide Setter의 반응성에 관한 연구)

  • 박정현;최현정;조경식;염강섭;조철구
    • Journal of the Korean Ceramic Society
    • /
    • v.31 no.6
    • /
    • pp.651-659
    • /
    • 1994
  • BaTiO3 ceramics were sintered on Al2O3, MgAl2O4, MgO and Mg-, Ca-, Y-stabilized zirconia setters. Then the influence of setters on the microstructure of BaTiO3 ceramics and the stability of setters were investigated by SEM, EDAX and XRD analyses. The microstructure of BaTiO3 ceramics sintered on Al2O3, MgAl2O4, MgO and Mg-PSZ showed large grain growth, but little grain growth on Ce-TZP(Tetragonal Zirconia Policrystal). Mg-PSZ(Partially Stabilized Zirconia), Ca-PSZ, Ce-TZP setters showed extensive phase transformation. Y-TZP and fused Y-SZ (Stabilized Zirconia) setters were stable. The liquid sintering aids of BaTiO3 ceramics accelerate mass transport. The reaction of SrTiO3 in BaTiO3 with ZrO2 resulted in the formation of SrZrO3.

  • PDF

The Effect of Al-powder as an additive on the Sintering of $Al_2O_3$ (II. In air,1600~180$0^{\circ}C$) (첨가된 알루미늄 분말의 산화가 알루미나 소결에 미치는 영향(II. 공지궁 1,600~1,80$0^{\circ}C$에서))

  • 박정현;전병세
    • Journal of the Korean Ceramic Society
    • /
    • v.21 no.3
    • /
    • pp.259-265
    • /
    • 1984
  • As the effect of Al-powder as an additive on the sintering of $Al_2O_3$ was found satisfacotry in the range of 1350-155$0^{\circ}C$ this experiment was carried out at higher temperature(1600-180$0^{\circ}C$) at which the commerical $Al_2O_3$ body is sintered. Some phsical properties were measured and the micostructures of the specimens were observed by SEM. Although some measured physical properties of the specimens were improved through the addition of Al powder to $Al_3O_2$ powder the systematic changes in microsturces of the specmens could not be observed by SEM.

  • PDF