• Korean Chemical Engineering Research
• /
• 제51권1호
• /
• pp.42-46
• /
• 2013

미역에서 후코산틴을 추출하는 공정과 후코산틴의 안정성에 대해 연구하였다. 본 연구에서는 후코산틴 추출물을 기능성 식품에 이용하기 위해 용매를 에탄올을 사용했다. 에탄올 농도가 80%일 때 후코산틴 추출 농도가 최고였다. $50^{\circ}C$까지 추출온도가 상승할 때 추출수율이 증가하였다. 원료를 5분간 물세척하여 후코산틴 중 염분농도를 약 94% 감소시켰다. 후코산틴이 $70^{\circ}C$에서 1일 저장 동안 30% 감소해, $70^{\circ}C$ 이상의 온도에서 열에 약함을 나타냈다. 그리고 빛 안정성 실험결과 후코산틴은 빛에도 매우 약함을 보였다.

• 한국식품과학회지
• /
• 제17권4호
• /
• pp.265-270
• /
• 1985

홍미삼을 원료로 홍삼엑기스를 조제할때 추출온도와 추출시간이 조사포닌의 수율과 ginsenoside의 구성에 미치는 영향을 조사하였다. 엑기스의 수율은 추출온도가 상승되고 추출회수가 증가될수록 증가되는 반면 조사포닌의 수율은 낮아지는 경향이 있으며 특히 $100^{\circ}C$의 경우 현저하여 열에 대한 불안정함을 보여주었고$80^{\circ}C$이하에서는 대체로 안정하였다. Ginsenoside별 구성율은 추출회수에 따라 큰 차이가 없어 용출의 특이성을 보이지 않았으나 용출율에서는 온도상승에 따라 감소되었으며 PT제에 비하여 PD계의 사포만의 감소율이 더 크게 나타나 열에 대한 안정성에서 차이를 보였다. 물 추출구(區) 및70%에탄올구(區)모두 $3{\sim}4$회 추출로 총사포닌의 94% 이상이 용출되었으며 초기용출은 물 추출구(區)가 더 컸다. 따라서 홍삼엑기스의 수율과 작업성 및 사포닌의 안정화 유지를 위한 적정 추출온도 및 추출회수는80이하에서 $3{\sim}4$회 추출하는 것이 적합한 것으로 판단되었다.

• Nuclear Engineering and Technology
• /
• 제53권1호
• /
• pp.188-198
• /
• 2021

A modern approach to nuclear energy involves reprocessing like transmutations of spent nuclear fuel products to reduce their radiotoxicity and time needed for their storage. For this purpose, they are immobilized in inert matrices made of zirconia and can be "burned" in fast neutron reactor or Accelerator Driven System. These matrices in spherical form can be obtained by sol-gel process. The paper presents a method of microspheres fabrication based on the combined Complex Sol-Gel Process and double extraction process consisting in the preparation of zirconium-ascorbate sol and simultaneous extraction of water and nitrates. The procedure allows obtaining gel microspheres with a diameter of 50 ㎛, which after heat treatment are processed into the final product. The synthesis of zirconia microspheres with Yttrium by internal gelation process is well known for over a decade now. However, the explanation and characterization of synthesis of such material by extraction of water process is rarely found. Parameters such as: pH, viscosity, shape, sphericity and crystal structure have been determined for synthesized products and semi-products. In addition, preliminary research consisting in irradiation of the obtained materials in fast and thermal neutron flux was carried out. The obtained results are presented and described in this work.

• 분석과학
• /
• 제33권2호
• /
• pp.76-85
• /
• 2020

A stainless-steel needle (Hamilton 90022, 22 gauge, 718-㎛ o.d., 413-㎛ i.d., 51-mm length, bevel tip) with an electrochemically coated polyaniline layer having a microbore tunnel was newly prepared as a device for headspace in-needle microextraction. For designing the needle, the polyaniline layer length was optimized, and to evaluate the extraction efficiency for polycyclic aromatic hydrocarbons, numerous cyclic voltammetry scans were conducted. In addition, the optimization of the analytical conditions (including the adsorption and desorption parameters) and the validation of the analytical method were conducted. The optimized adsorption and desorption conditions were 40 ℃ for 30 min and 230 ℃ for 60 s, respectively. Finally, in this study, a polyaniline layer was electrochemically deposited on the in-needle surface, and it exhibited good thermal stability. The needle with the polyaniline layer was repeatedly used more than 200 times during this study. This method has some advantages in terms of the extraction time, extraction efficiency, and analysis cost.

• 자원리싸이클링
• /
• 제26권3호
• /
• pp.69-78
• /
• 2017

최근 국내 자동차부품 및 전자기기 산업에서 마그네슘 금속의 수요가 증가하고 있다. 마그네슘 제련은 크게 용융염전해법과 열환원법 두 가지로 대별할 수 있는데, 본 고에서는 마그네슘 금속 제련에 관하여 원료 광석인 마그네사이트로부터 무수염화마그네슘 제조를 거쳐 용융염전해법에 의한 금속 마그네슘 제조까지 실험실 규모로 전해 마그네슘을 제조한 내용을 요약 보고하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
• /
• pp.1819-1824
• /
• 2006

A microlens arrays formed by thermal reflow method is attached to an OLED device and the light extraction efficiency which includes luminance and power information is determined by adjusting the area ratio and the height ratio.

• 한국측량학회지
• /
• 제34권6호
• /
• pp.619-627
• /
• 2016

Cells of a PV (photovoltaic) module can suffer defects due to various causes resulting in a loss of power output. As a malfunctioning cell has a higher temperature than adjacent normal cells, it can be easily detected with a thermal infrared sensor. A conventional method of PV cell inspection is to use a hand-held infrared sensor for visual inspection. The main disadvantages of this method, when applied to a large-scale PV power plant, are that it is time-consuming and costly. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule was applied to automatically detect defective panels using the mean intensity and standard deviation range of each panel by array. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97% or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule. In this study, we used a panel area extraction method that we previously developed; fault detection accuracy would be improved if panel area extraction from images was more precise. Furthermore, the proposed algorithm contributes to the development of a maintenance and repair system for large-scale PV power plants, in combination with a geo-referencing algorithm for accurate determination of panel locations using sensor-based orientation parameters and photogrammetry from ground control points.

• Carbon letters
• /
• 제11권2호
• /
• pp.127-130
• /
• 2010

Boron doped fullerene $C_{60}$ ($B:C_{60}$) films were prepared by the thermal evaporation of $C_{60}$ powder using argon plasma treatment. The morphology and structural characteristics of the thin films were investigated by scanning electron microscope (SEM), Fourier transform infra-red spectroscopy (FTIR) and x-ray photo electron spectroscopy (XPS). The electrochemical application of the boron doped fullerene film as a coating layer for silicon anodes in lithium ion batteries was also investigated. Cyclic voltammetry (CV) measurements were applied to the $B:C_{60}$ coated silicon electrodes at a scan rate of $0.05\;mVs^{-1}$. The CV results show that the $B:C_{60}$ coating layer act as a passivation layer with respect to the insertion and extraction of lithium ions into the silicon film electrode.

• 한국태양에너지학회 논문집
• /
• 제22권1호
• /
• pp.31-42
• /
• 2002

This study has been carried out to design a number of storage units which could improve the utilizability of solar energy by offering convenient means to store it. The proposed units are systematically tested to establish their reliability in actual operations. One of the prominent features of the present storage units is that each design is meant to drastically improve the thermal response of solar systems which would definitely offer extreme convenience to whoever uses it. Also sought in the present study is to elicit ideal operating conditions during the storage and extraction phases of solar energy once it is delivered to the storage unit. The present study has confirmed the potential use of the proposed units with their applicability in capitalizing the sun's energy.

• Mass Spectrometry Letters
• /
• 제5권1호
• /
• pp.12-15
• /
• 2014

Thermal ionization mass spectrometry (TIMS) was used to determine the concentration and isotope ratio of uranium contained in samples of soil and groundwater collected from Korea. Quantification of uranium in ground water samples was performed by isotope dilution mass spectrometry. A series of chemical treatment processes, including chemical separation using extraction chromatography, was applied to the soil samples to extract the uranium. No treatments other than filtration were applied to the groundwater samples. Isotopic analyses by TIMS showed that the isotope ratios of uranium in both the soil and water samples were indistinguishable from those of naturally abundant uranium. The concentration of uranium in the groundwater samples was within the U.S. acceptable standards for drinking water. These results demonstrate the utility of TIMS for monitoring uranium in environmental samples with high analytical reliability.