• The Korean Journal of Mycology
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• v.31 no.2
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• pp.94-97
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• 2003

In order to shorten cultivation periods of Agrocybe cylindracea, liquid spawn was used in place of sawdust spawn. Optimum culture condition of liquid spawn was PSB (potato extract sugar broth) medium, $25^{\circ}C$ temperature and pH 7.0. And, optimum inoculum volume was $10{\sim}15ml$. Two grams per liter of dry weight of the fungal mycelia were obtained with 10l of culture bottle with liquid spawn after 10 days. In 850 ml-bottle of sawdust media, cultivation period using liquid spawn (30 days) was five days shorter compared with the cultivation period in sawdust spawn (35 days). Also, complete growth of sawdust media was increased to 92% (liquid spawn) from 75% (sawdust spawn) and yield of fruiting bodies was increased to about 10%.

• Resources Recycling
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• v.28 no.2
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• pp.46-53
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• 2019

In this study, the extraction and reduction behavior of platinum group metals in a non-aqueous solvent based on ionic liquids was investigated in order to confirm a new extraction technology of platinum group metals. Platinum was selectively extracted using an ionic liquid $[C_4mim]PF_6$ from a mixed solution of $PdCl_2$, $PtCl_4$ and $RhCl_3$ dissolved with concentration ratio of 10:1:0.5 M. After stripping of the metals by 1 M $HNO_3$ solution, the platinum was preferentially reduced by aqueous electrolysis on gold electrode at -0.8 V (vs. Pt-QRE). The residual palladium and rhodium were transferred to ionic liquid of $[C_4mim]Cl$. The metallic palladium and rhodium could be sequentially reduced on gold and STS304 as working electrodes by non-aqueous electrolysis, respectively.

• Analytical Science and Technology
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• v.28 no.3
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• pp.228-235
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• 2015

The efficiency and applicability of the solid phase extraction disk method in a ²²⁶Ra analysis were examined by the gamma ray spectrometer (GRS) method using a Marinelli beaker and the liquid scintillation counter (LSC) method for groundwater. The recovered ²²⁶Ra, which was filtered by the solid phase extraction disk, was analyzed using gamma ray spectrometer The disks, which were pretreated for caulking the daughter nuclide, were sealed with polyethylene film. Distilled water was used for the blank value of the ²²⁶Ra activity. The recovery values of ²¹⁴Bi and ²¹⁴Pb in the solid phase extraction disk, which used ²²⁶Ra standard material, were 80% (295.21 Kev) and 104% (351.92 Kev), respectively, which were higher than 75% determined by the LSC. The injection of nitrogen gas into the measuring chamber reduced the interference values by about 10%. The detection limits of the ²²⁶Ra activity in a blank sample of 5 L were 0.17~0.40 pCi/L after 80,000 seconds of measuring time. The relationship of the ²²⁶Ra activity in the solid phase extraction disk method and in the LSC method in seven groundwater samples showed a correlation coefficient value 0.987, which implies the applicability of the solid phase extraction disk method. The results showed that ²²⁶Ra activity in groundwater using the solid phase extraction disk method has the following benefits: simple pretreatment, time saving, high recovery values, a low detection limit, and so on. Compared with the LSC method and the GRS method using the Marinelli beaker for the ²²⁶Ra analysis, the solid phase extraction disk method could be useful in groundwater samples with low levels of activities of radionuclides because the method is not restricted by the volume of the sample.

• Journal of Korean Society for Atmospheric Environment
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• v.4 no.2
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• pp.11-19
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• 1988

대기오염물질 속에 함유되어 있는 다환방향족 탄화수소 (PAHs)는 분자식 구조가 비슷한 수십개의 이성질체가 여러 종류의 유기화합물과 혼합되어 존재한다. 본 연구에서는 환경오염 시료중의 PAHs를 분석하는데 있어서 분석방법과 결과를 비교하기 위하여 지침이 될 수 있는 환경표준 기준물을 개발할 목적으로 굴뚝 안쪽벽에서 긁어 채취한 검댕을 시료로 선책하여 액체/액체 용매 추출방법에 의해 PAHs 분류부분을 얻었다. Phenanthrene 이외의 30여종의 PAHs 화합물을 가스크로마토그라피의 머무른시간과 가스크로마토그라피/질량분석기에 의하여 분리, 판명하였고 5종의 주 PAHs 화합물을 정확하게 정량 분석하였다. 정량분석 결과의 신뢰도, 정확도, 정밀도는 미국 NBS의 표준기준물 1647을 분석하여 검정치와 비교함으로써 평가하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.316.1-316
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• 2002

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.393.1-393
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• 2002

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.251-252
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• 2016

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.441-442
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• 2016

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.139-140
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• 2012

• Clean Technology
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• v.26 no.2
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• pp.102-108
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• 2020

In recent years, packed column has been widely used in separation processes, such as absorption, desorption, distillation, and extraction, in the petrochemical, fine chemistry, and environmental industries. Packed column is used as a contacting facility for gas-liquid and liquid-liquid systems filled with random packed materials in the column. Packed column has various advantages such as low pressure drop, economical efficiency, thermally sensitive liquids, easy repairing restoration, and noxious gas treatment. The performance of a packed column is highly dependent on the maintenance of good gas and liquid distribution throughout a packed bed; thus, this is an important consideration in a design of packed column. In this study, hydraulic pressure drop, hold-up as a function of liquid load, and mass transfer in the air, air/water, and air-NH₃/water systems were studied to find the geometrical characteristic for raschig super-ring experiment dry pressure drop. Based on the results, design factors and operating conditions to handle noxious gases were obtained. The dry pressure drop of the random packing raschig super-ring was linearly increased as a function of gas capacity factor with various liquid loads in the Air/Water system. This result is lower than that of 35 mm Pall-ring, which is most commonly used in the industrial field. Also, it can be found that the hydraulic pressure drop of raschig super-ring is consistently increased by gas capacity factor with various liquid loads. When gas capacity factor with various liquid loads is increased from 1.855 to 2.323 kg^-1/2 m^-1/2 S^-1, hydraulic pressure drop increases around 17%. Finally, the liquid hold-up related to packing volume, which is a parameter of specific liquid load depending on gas capacity factor, shows consistent increase by around 3.84 kg^-1/2 m^-1/2 S^-1 of the gas capacity factor. However, liquid hold-up significantly increases above it.