• 분석과학
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• 제30권5호
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• pp.226-233
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• 2017

In general, quantitative chemical analysis in various areas including food, the environment, in vitro diagnostics, etc., requires traceability in order to increase the reliability of the measurements. Measurement traceability is a property of an unbroken chain of comparisons relating an instrument's measurements to SI units. Purity analysis is the first process for establishing traceability to SI units in chemical measurements. The purpose of this study is to develop and validate a method of purity assignment for establishing the traceability of $17{\beta}$-estradiol measurements in an in vitro diagnostics field. The establishment of this method is very important as it can be applied to the development of CRM and to the analysis of the purity of other hormones. The method of assignment of the purity of $17{\beta}$-estradiol was developed using the mass balance method and was validated through participation in an International comparison. In the mass balance method, impurities are categorized into four classes as follows: total related structure impurities, water, residual organic solvents, and nonvolatiles/inorganics. In this study, total related structure impurities were characterized by a gas chromatography-flame ionization detector (GC-FID) and a high-performance liquid chromatography-ultraviolet (HPLC-UV) detector, water content was determined by a Karl-Fisher coulometer, and total residual solvents and nonvolatiles/inorganics were checked simultaneously by thermogravimetric analysis (TGA). The purity of the $17{\beta}$-estradiol was 985.6 mg/g and the expanded uncertainty was 2.1 mg/g at 95% confidence. The developed method can be applied to the development of certified reference materials, which play a critical role in traceability.

• 센서학회지
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• 제7권2호
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• pp.117-123
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• 1998

알루미나 기판위에 스핀코팅에 의해 $In_{2}O_{3}$ 박막을 형성하고 그 박막의 미세구조와 가스감지특성을 조사하였다. 코팅용액은 $In(OH)_{3}$ 수용액에 초산을 첨가하여 합성되었다. 이 용액에 바인더로써 암모니아 카르복실 셀루로오스를 섞어서 코팅용액으로 사용하였다. 이 용액을 $1{\sim}7$회 스핀코팅하고 $110^{\circ}C$에서의 건조와 $600^{\circ}C$에서의 열처리에 의해 두께 $71{\sim}210nm$의 $In_{2}O_{3}$ 박막을 얻을 수 있었다. 제조된 박막은 미세한 $In_{2}O_{3}$ 결정입자($23{\sim}27nm$)가 적층된 형태의 구조를 가지고 알루미나 기판의 결정입위에 균일하게 코팅되었다. 박막의 두께는 스핀코팅의 횟수에 선형적으로 증가하였다. 제조된 박막은 CO, $H_{2}$ 가스에 대해 높은 감도와 빠른 응답특성을 나타내었다.

• 열처리공학회지
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• 제21권6호
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• pp.293-299
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• 2008

In order to provide with fundamental data of the wrought Mg alloy for press forging, the effect of annealing temperature on the microstructure, texture development and tensile properties is studied in a commercial AZ31B Mg alloy sheet. Basal texture i.e. $(0001){\pm}5^{\circ}$[21$\bar{3}$0] is developed in a commercial AZ31B Mg sheet, and the texture is not changed considerably by annealing over $400^{\circ}C{\times}30min$, while (10$\bar{3}$0) component with high intensity can be observed due to abnormal grain growth. When the sheet is tensile-deformed with RD, $45^{\circ}$ and TD directions at room temperature, fracture strains are given by 25.8, 21.4 and 11.9% in the order of RD, $45^{\circ}$ and TD directions, respectively. With increasing annealing temperature up to $450^{\circ}C{\times}30min$, little change in mean grain size can be revealed by annealing below $300^{\circ}C{\times}30min$ but an abnormal grain growth, where some grains become significantly coarser than the rest, occurs by annealing above $400^{\circ}C{\times}30min$. The maximum tensile strain of around 25% is obtained by annealing below $300^{\circ}C{\times}30min$, but it is abruptly decreased to 16% by annealing above $400^{\circ}C{\times}30min$ owing to intergranular fracture of abnormal grown grains.

• 한국식생활문화학회지
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• 제27권3호
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• pp.233-239
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• 2012

The purpose of this study was to develop an evaluation indicator for the industrialization of local cuisine. We conducted a literature study, interviews with experts, and a Delphi survey. The resulting evaluation indicator was divided into four groups and nine sub-groups. The four groups were locality, taste and functionality, industrial base, and business value. The nine sub-groups were traditionality, regionality, eating quality, nutrition and functionality, condition of development, technological level, rights and policy, marketability, and ripple effects. Also 22 items were created as indicators for evaluating classes ; historicity, sustainability, rarity, awareness of local resident, the number of similar restaurant, appearance, taste, nutritional balance, health functionality, availability of raw materials, suitability of environmental exchange of market, standardization of recipe, simplification of recipe, storability, intellectual property rights, government's policy, appropriacy of price, popularization, possibility of franchise, globalization, improvement of local image, vitalization of local economy. The four most important classes corresponded to one of the four groups. These classes were sustainability, taste, state (local autonomy) policy, vitalization of local economy. The implications of this study are that the possibility of industrializing the local cuisine of each region can be evaluated and applied. Moreover, these indicators could promote the discovery of local cuisines, support planning for the commercialization of local cuisine.

• 대한의용생체공학회:의공학회지
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• 제20권2호
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• pp.213-220
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• 1999

본 연구는 쥐의 뇌, 심장, 간, 근육 및 근육부위의 종양조직과 인간의 뇌 조직과 뇌 종양 조직의 광학적 흡수계수를 500nm~900nm 범위의 파장에서 측정하고 비교분석하였다. 광학적 흡수계수는 물질마다 가지고 있는 고유한 성질을 나타내므로 생체조직의 광학계수를 측정하면, 생체 조직의 고유한 특성을 나타낼 수 있다. Spectrograph monometer와 PDA를 이용하여, 동결절편으로 제작한 시편에 대하여 실험하였다. 실험결과, 쥐 조직과 인체의 뇌 조직의 흡수계수는 정상적인 일반 조직과 종양 조직에서 차이가 분명하게 있음을 알 수 있었다. 정상 뇌 조직의 흡수계수는 파장이 변화함에 따라 0.1~0.2$cm^{-1}$사이의 비교적 균일한 값을 보이는데 반하여, 뇌종양 조직의 흡수계수는 파장에 따라서 크게는 약 0.4~0.5$cm^{-1}$정도의 변화가 있다. 본 실험 결과들은 다양한 조직에서의 광학계수 중에서 흡수계수를 측정함으로써, 생체조직의 흡수계수의 변화를 감지하여 질병진단의 지표로 삼을 수 있다.

• 한국식품과학회지
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• 제20권4호
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• pp.470-475
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• 1988

압출성형시 원료의 수분함량이 낮을수록 팽화율이 커졌으며, 수분함량이 증가되면 호화도, 가밀도 및 전단강도가 증가하였다. 또한 아밀로그램이나 리올로지 특성에 있어서도 수분함량이 증가할수록 점도가 증가하였으며 의가소성 유동특성을 보여주었다. 수분함량이 증가하면 WAI값은 증가하나 WSI값은 감소하였다. 수분함량이 낮으면 황색도가 증가하였다. 미세구조에 있어서도 수분 함량이 높을수록 전분질의 호화특성을 관찰할 수 있었다. 품종간의 대체적인 물성특성은 삼강보다는 추청품종이 우수하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권3호
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• pp.146-152
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• 2009

Traditional surgical method or injection using filler is performed for soft tissue augmentation. Surgical methods have disadvantage of surgical morbidity. Commercially available injectable materials have the disadvantages such as resorption, short-term effect. repeated application and hypersensitivity. Significant shortcoming of cell therapy using autologous fibroblasts is delay of treatment effect. Chitosan/${\beta}$-glycerol phosphate (GP) solution has thermosensitive property and allows sol-gel transition at physiologic pH and temperature. These properties may resolve the delay of treatment effect. The purposes of this study are to evaluate the viscosity and pH changes of chitosan/${\beta}$-GP solutions and to evaluate the effect of chitosan/${\beta}$-GP solution on fibroblast proliferation and production of collagen. We measured the viscosity and pH as function of temperature, of the solution containing 1:0.7, 1:0.75, 1:0.8 chitosan (1, 10, 100, 700 kDa) /${\beta}$-GP. Fibroblasts from ears of 5 rats were cultured in chitosan/${\beta}$-GP solutions for 3 weeks. Cell proliferation and collagen contents were measured every week with WST (water-soluble tetrazolium salt) assay and Collagen assay respectively. The Results are 1) Chitosan(100 kDa<)/${\beta}$-GP solution (1:0.75) showed sol-gel transition at physiologic pH and body temperature and injectable properties. It will enable to resolve the delay in treatment effect 2) Cell proliferation and total collagen contents of the control group were increased with time. However, these decreased after the 1st week in experimental group 3) Collagen contents in the experimental group are higher than that of control group. Chitosan/${\beta}$-GP solution may provide favorable conditions for cell function

• Imaging Science in Dentistry
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• 제38권1호
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• pp.49-56
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• 2008

Purpose: Diagnostic estimation of destruction and formation of bone has the typical limit according to capacity of x-ray generator and image detector. So the aim of this study was to find out how much it can reproduce the shape and the density of bone in the case of using recently developed dental type of cone beam computed tomography, and which image is applied by new detector and mathematic calculation. Materials and Methods: Cone beam computed tomography (PSR 9000N, Asahi Roentgen Ind. Co., Ltd., Japan) and soft x-ray radiography were executed on dry mandible that was already decalcified during 5 hours, 10 hours, 15 hours, 20 hours, and 25 hours. Estimating and comparing of those came to the following results. Results: The change of inferior border of mandible and anterior border of ramus in the region of cortical bone was observed between first 5 and 10 hours of decalcification. The reproduction of shape and density in the region of cortical bone and cancellous bone can be hardly observed at cone beam computed tomography compared with soft x-ray radiography. The difference of decrease of bone density according to hours of decalcification increase wasn't reproduced at cone beam computed tomography compared with soft x-ray radiography. Conclusion: CBCT images revealed higher spatial resolution. However, contrast resolution in region of low contrast sensitivity is the inferiority of images' property.

• Korean Chemical Engineering Research
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• 제55권1호
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• pp.115-120
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• 2017

현재 세계적인 이슈가 되고 있는 나노과학과 기술은 탄소나노튜브(CNTs)를 기반으로 한 바이오센서 성능 향상에 주력하고 있다. 다양한 기능성을 가진 CNTs는 높은 안정성과 바이오 수용체와 같은 생체물질과의 높은 적합성으로 이를 이용한 바이오 전극 기술에 힘입어 의학, 식품 및 환경에서 이슈가 되는 물질들을 검출하기 위한 산업적 응용 연구가 주목받고 있다. 본 연구에서는 이러한 CNTs를 이용한 전기화학적 바이오센서에 있어서 시료가 액체 상태로 검출이 예상되는데 그 시료의 화학적 특성에 따른 금 전극 사이에 고정화된 CNTs의 전자전달현상을 조사하였다. 그 결과, 시료가 극성인 경우와 무극성인 경우 고정화된 CNTs의 전자전달 현상이 다르게 나타났으며, 극성의 세기가 증가할수록 전자의 이동에 방해를 받는 것으로 확인되었다. 이는 CNTs의 양끝에 존재하는 극성 작용기와의 상호작용에 의한 것으로서 센서 디바이스 전체를 시료 용액에 침투시켜 전자이동을 관찰한 결과와 달리 안정적으로 저항값을 나타내는 것으로 확인되었다. 향후 민감도가 높은 CNTs 기반 나노바이오센서 개발 시 시료의 효과적인 전처리 공정에서 이러한 용매의 극성을 고려한 최적화 연구가 필요하다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권8호
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• pp.348-353
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• 2003

This paper was the research of high voltage suspension insulator (400 [kN]) including pottery stone, feldspar, clay and alumina of 17 [wt%]. The slurry was fabricated after ball milling mixed raw materials. Green compacts were made by the extrusion of jiggering method and were sintered at 1300[$^{\circ}C$] for 50 [min.] in the tunnel kiln. The sintered density was reached to 97% of theoretical density, and the bending strength was 1658 [k $g_{f}$/$\textrm{cm}^2$] and hardness and fracture toughness which was measured by ICL( indentation crack length ) method were 1658 (kgf/$\textrm{cm}^2$) and 27.5 [Gpa], respectively. In measurement of tana and insulation break voltage of 400 (kN) porcelain, tan$\delta$ took some numerical value between 17${\times}$10$_{-3}$ and 61${\times}$10$_{-3}$ and insulation break voltage value was 19.9$\pm$1.4 [㎸/mm]. The test was performed to research whether the shape of pin affect a overvoltage break load or not As a consequence, when a pin was designed a pin diameter 51 [mm] with the bottom form of two-step constructed with straight in the suspension insulator, Insulator showed overvoltage break load 52 [ton] of the highest value and reflected a fine characteristic in aged deterioration test which is one of the accelerated aging test. Also it could be confirmed a fine characteristic through performing the test that electrical property of insulator was established correctly in accordance with IEC 60383-1 standards.s.