• 한국세라믹학회지
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• 제38권11호
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• pp.973-979
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• 2001

Sn을 도핑한 In$_2$O$_3$(ITO) 박막을 R.F. 마그네트론 반응성 스퍼터링법에 의해서 증착하였다. 동일한 마그네트론 스퍼터링 조건에서 증착위치에 따른 ITO 박막의 저항, 자유 전하 농도 및 이동도 전기적 특성을 조사하였다. 동일한 마그네트론 스퍼터링 조건임에도 불구하고, ITO 박막의 전기적 특성은 증착위치에 따라 불균질성을 나타내었다. 타겟의 중심에 위치한 기판위에 증착된 ITO 박막의 저항은 최소 값인 2~4$\times$$10^{-4}$ $\Omega$.cm인 반면, 중심에서 멀어질수록 박막의 전기 저항은 대칭적으로 증가하였다. ITO 박막의 밀도 측정 결과도 중심에서 이론 밀도 값의 97%에 해당하는 7.0g/$cm^3$를 나타내나, 위치가 중심에서 멀어질수록 박막의 밀도가 대칭적으로 감소하였다. ITO 박막에서 이동도와 전도도는 밀도에 직접적으로 영향을 받는 것이 실험적으로 확인되었다. ITO 박막의 밀도가 7.0g/$cm^3$(이론 밀도의 97%)인 경우, 자유행정거리와 입자크기(=주상의 직경)가 동일한 값을 가지나, 밀도가 이 보다 감소하면 자유행정거리와 입자크기의 차이는 더욱 증가하였다. 이 결과는 ITO 박막의 밀도가 7.0g/$cm^3$인 경우는 입계가 자유 전자의 전도에 중요한 산란 원으로 작용하는 반면, 그 외의 경우는 결정 내의 공격자점, 공공, 기공 등이 다른 산란 원으로 작용하고 있다는 것을 나타낸다.

• Tuberculosis and Respiratory Diseases
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• 제64권3호
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• pp.219-223
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• 2008

저자들은 대량 객혈로 내원한 환자에서 폐 출혈과 함께 반복적인 심인성 폐부종, 카테콜라민 유도성 심부전이 합병된 드문 형태의 갈색세포종을 경험하여 이러한 임상 증상시 폐나 심장 질환 외에 갈색세포종에 대한 고려가 필요할 것으로 생각되어 문헌고찰과 함께 보고하는 바이다.

• 대한소아치과학회지
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• 제24권4호
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• pp.763-770
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• 1997

The air abrasive technique is a non-mechanical method by which teeth are treated before restoration and stains and calculi are removed from tooth surfaces using the kinetic energy of small particles. The air abrasive technique in dentistry was first introduced in the 1950's with as instrument called 'Airdent'. But, as the main restorative materials of the period were amalgam and gold, and the instrument's inability to control the flow of particles caused the particles to be spread throughout the clinics, widespread use was not possible. In the 1990's, as these techincal problems were solved and more interest in new restorative materials rose in an effort to preserve sound tooth structure, new developements took place in instruments related to the air abrasive technique. The air abrasive technique produces less pressure, vibration and heat that might cause patient discomfort and facilitates the preservation of sound tooth structure. It also reduces the need for anesthesia and is less harmful to the pulp. Other advantages include increase in dentin bonding strength of composite resin, lower possibility of saliva contamination and maintenance of a dry field. But there is not direct contact between the nozzle and the tooth, the operator cannot use his or her tactile sense and must rely solely upon visual input. Other disadvantages are: the tooth preparation depends on the operator's ability; alpha-alumina particles, after bouncing off the tooth surface, cause damage to dental mirrors; the equipment is expensive and takes up a certain amount of space in the clinic. The author conducted case report using the air abrasive technique on patient visiting the Department of Pediatric Dentistry at Seoul National University Dental Hospital and arrived at the following conclusions. 1. The tooth preparation capability of different air abrasive devices varied widely among manufacturers. 2. It was more effective in treating early caries lesions and stains compared to lesions where caries had already progressed to produce soft dentin. 3. The cold stream and noise caused by the evacuation system was a major cause of discomfort to pediatric patients. 4. As there is no direct contact with tooth surface when using the air abrasive technique for tooth preparation, considerable experience and skill is required for proper tooth preparation.

• 한국자기학회지
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• 제7권5호
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• pp.243-248
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• 1997

Ar+ $O_{2}$ 혼합가스 중에서 반응성 스퍼터링을 통해 직접 Fe-Hf-O계 초미세결정 연자성 박막을 제조하였으며, 이때 산소분압비의 변화가 Fe-Hf-O 박막의 미세구조 및 자기적 특성에 미치는 영향을 조사하였다. 산소분압이 증가함에 따라 박막의 포화자속밀도는 점차적으로 감소하며 연자기특성이 10%까지는 향상되다가 다시 열화되는 경향을 나타내었다. 최적조건인 10%의 산소분압에서 증착한 F $e_{82}$H $f_{3.4}$ $O_{14.6}$ 초미세결정 박막은 열처리 없이 증착한 상태에서 우수한 연자기 특성을 나타내었으며, 이때의 자기적 특성은 각각 포화자속밀도 17.7 kG, 보자력 0.7 Oe 및 실효투자율 2,500(100 MHz)의 값을 나타내었다. 산소분압이 증가함에 따라 결정립 크기가 감소하며 15% 이상의 산소분압에서는 F $e_{3}$ $O_{4}$가 생성되었다. 따라서 10%에서 가장 우수한 연자기 특성을 나타내는 것은 결정립 크기와 산화물 생성에 의해 설명될 수 있다. Fe-Hf-O계 초미세결정 박막의 전기비저항은 산소분압이 증가함에 따라 증가하는 경향을 나타내었다. 우수한 연자기 특성을 나타내는 F $e_{82}$H $f_{3.4}$ $O_{14.6}$ 박막의 경우, 약 150 .mu. .ohm.cm로 산소를 첨가하지 않은 경우의 30 .mu. .ohm. cm에 비하여 약 5배 증가된 값을 나타내었다. 따라서 F $e_{82}$H $f_{3.4}$ $O_{14.6}$초미세결정 박막이 고주파에서 우수한 연자기 특성을 나타내는 원인은 주로 높은 전기비저항과 미세하게 형성된 결정립에 기이한 것으로 생각된다.

• Corrosion Science and Technology
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• 제13권1호
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• pp.28-35
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• 2014

Recently, the fuel oil of diesel engines of marine ships has been increasingly changed to heavy oil of low quality as the oil price is getting higher and higher. Therefore, the spiral gear attached at the motor of the oil purifier which plays an important role to purify the heavy oil is also easy to expose at severe environmental condition due to the purification of the heavy oil in higher temperature. Thus, the material of the spiral gear requires a better mechanical strength, wear and corrosion resistance. In this study, the heat treatment(tempering) with various holding time at temperature of $500^{\circ}C$ was carried out to the alloy of Cu-7Al-2.5Si as centrifugal casting, and the properties of both hardness and corrosion resistance with and without heat treatment were investigated with observation of the microstructure and with electrochemical methods, such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram, and a.c. impedance. in natural seawater solution. The ${\alpha}$, ${\beta}^{\prime}$ and ${\gamma}_2$ phases were observed in the material in spite of no heat treatment due to quenching effect of a spin mold. However, their phases, that is, ${\beta}^{\prime}$ and ${\gamma}_2$ phases decreased gradually with increasing the holding time at a constant temperature of $500^{\circ}C$. The hardness more or less decreased with heat treatment, however its corrosion resistance was improved with the heat treatment. Furthermore, the longer holding time, the better corrosion resistance. In addition, when the holding time was 48hrs, its corrosion current density showed the lowest value. The pattern of corroded surface was nearly similar to that of the pitting corrosion, and this morphology was greatly observed in the case of no heat treatment. It is considered that ${\gamma}_2$ phase at the grain boundary was corroded preferentially as an anode. However, the pattern of general corrosion exhibited increasingly due to decreasing the ${\gamma}_2$ phase with heat treatment. Consequently, it is suggested that the corrosion resistance of Cu-7Al-2.5Si alloy can be improved with the heat treatment as a holding time for 48 hrs at $500^{\circ}C$.

• 한국식생활문화학회지
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• 제19권2호
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• pp.170-176
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• 2004

천연첨가물검색의 일환으로 초피의 용매 추출물의 항산화성과 항균성을 실험하고, 소비자의 수용도를 검토하기 위하여 초피를 첨가한 육원전의 관능 검사를 실시한 결과는 다음과 같았다. 1. 초피 용매 추출물들의 옥수수유에 대한 항산화 효과는 가장 많이 사용되는 합성항산화 제인 BHT과 같은 농도에서 BUex는 월등히 높았으며, MEex, EAex는 유사한 경향을 나타냈다. 2. 초피의 용매 추출물의 중 CHex와 BUex가 Escheria coli, Salmonella typhimurium, Psudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus 및 Listeria monocytogenes 모두에 대하여 항균효과를 보였다. 3. 초피 가루를 식품에 첨가하여 제조한 육완자전에 대한 소비자의 기호도를 검사한 결과는 0.1%를 첨가한 경우는 초피를 첨가하지 않은 본래의 육완자전과 같은 수준의 기호도를 나타내므로써(P<0.05) 초피 가루에 의한 이미(異味)가 없어 육와자전 제조에 초피가루를 사용 할 수 있을 것으로 사료된다.

• 한국물환경학회지
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• 제23권2호
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• pp.201-205
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• 2007

This paper reports the amount of $^{222}Rn$ and $^{238}U$ in 18 sites of ground water and 30 sites of surface water. The instrument used to count $^{222}Rn$ activity was the liquid scintillation counter (LSC) which could resolute ${\alpha}$ and ${\beta}$ radiations. And $^{238}U$ was analyzed by the inductively coupled plasma (ICP). Radon and Uranium were not detected in raw and treated water which were sampled in a water treatment plant. However, radon ($^{222}Rn$) was high concentration in ground water from Jeon-la, Gang-won. So was uranium ($^{238}U$) in case of ground water from Gang-won, Choong-chung. Radon ($^{222}Rn$) activities were detected less than 15 pCi/L at 5 sampling points, 15~300 pCi/L at 7 sampling points, 300~4000 pCi/L at 6 sampling points. However, Radon ($^{222}Rn$) activities of all ground water samples were less than 4,000 pCi/L, which was bellow American Alternative Maximum Contamination Level (AMCL). Uranium ($^{238}U$) concentrations were less than $0.1{\mu}g/L$ at 5 sampling points, from $0.1{\mu}g/L$ to $20{\mu}g/L$ at 13 sampling points. Uranium was not detected in about 30% of the whole samples, but the concentration ranged from relatively low to high concentrations depending on the sampling point. The minimum detectable activity (MDA) of radon was 15 pCi/L. and the detection limit of uranium was $0.1{\mu}g/L$.

• 대한두경부종양학회지
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• 제13권1호
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• pp.16-23
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• 1997

Although normal thyroid epithelial cells do not constitutively express HLA-DR antigen, their expression in wide spread within thyroid glands obtained from the human with autoimmune thyroid disease and with many neoplastic thyroids. We have, therefore, studied immunohistochemically with regard to the expression of HLA-DR antigen of thyroidectomy specimens from 50 patients of various thyroid diseases with use of paraffin-embedded tissue. One or two sections from each case were stained with commercially available mouse monoclonal antibody for class II HLA-DR antigen(HLA-DR/Alpha, DAKO) and examined by semiquantitative counting system for thyrocytes, neoplastic thyrocytes and other cells expressing HLA-DR antigen. All patients with lymphocytic thyroiditis(2/2) and diffuse hyperplasia(Graves' disease)(5/5), most patients with Hashimoto's disease(9/ll) expressed HLA-DR antigens in thyrocyte with abundant HLA-DR expressing lymphocytic infiltrates with lymph follicle formation in its vicinity or adjacent to the lesion. Most patients with papillary carcinoma(9/1l) had HLA-DR antigen detected in malignant thyrocytes ; while follicular carcinoma(0/3) and follicular adenoma(0/5) did not have detactable HLA-DR immunoreactivity. Adenomatous goiter(3/7) had HLA-DR antigen detected focally in lesser than half cases. Conversely, in four papillary carcinomas and three adenomatous goiters, HLA-DR expression of thyrocytes was found in the absence of HLA-DR expressing lymphoid infiltrates. In such cases therefore other factors more than thyroid autoimmunity must be causative for HLA-DR immunoreactivity. The results of this study indicate as follows. 1) The expression of HLA-DR on thyrocytes involved in autoimmune reactions appeared to be secondary to cytokine release from associated lymphocytic infiltrates. 2) Thyrocytes in thyroid lesions with equal degrees of lymphocytic infiltration without HLA­DR expression exhibited no HLA-DR immunoreactivity. 3) In neoplastic thyrocytes, most papillary carcinoma(9/11) exhibited detactable HLA-DR expression, while follicular carcinoma/adenoma(0/3/0/5) exhibited no detactable HLA-DR immunoreactivity which suggest the existence of divergent mechanisms inducing and modulating HLA-DR expression of different types of neoplastic thyrocytes.

• 한국식품영양과학회지
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• 제45권3호
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• pp.445-451
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• 2016

본 연구는 고사리 및 취나물과 같은 산채가 첨가된 된장 및 일반 된장의 면역 활성을 비교하기 위하여 선천면역계의 대표적인 세포인 대식세포와 적응면역계에서 중추적인 역할을 수행하는 비장세포에 각각 산채첨가 된장 추출물(WPDJ) 및 일반 된장(DJ) 추출물을 처리하여 각각의 면역세포의 세포증식률과 사이토카인 분비능에 미치는 영향에 관하여 측정하여 보았다. 대식세포 및 비장세포에 WPDJ 및 DJ를 125, 250 및 $500{\mu}g/mL$의 농도로 처리하였을 때 두 추출물 모두 대식세포 및 비장세포에 대한 세포독성을 유발하지 않았으며, 농도 의존적으로 세포증식률을 증가시키는 것으로 관찰되었다. 대식세포의 사이토카인의 분비능에 관하여 알아본 결과 WPDJ 처리구에서 더 높게 증가하는 것으로 관찰되었다. 또한 마우스 비장에서 유리된 비장세포에 WPDJ 및 DJ를 125, 250 및 $500{\mu}g/mL$의 농도로 처리하였을 때 Th1 type의 사이토카인인 IL-2와 IFN-${\gamma}$의 분비능은 유의적으로 증가한 반면, 알레르기를 유도하는 것으로 알려진 Th2 type의 사이토카인인 IL-4의 생성에는 영향을 미치지 않는 것으로 관찰되었다. 따라서 산채를 첨가하여 제조한 된장은 일반 된장보다 면역 활성을 더 높게 증가시키는 것으로 생각한다.