• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.65-68
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• 2009

The Stirling cryocoolers have been widely used for the cooling of the infrared detector(InSb, HgCdTe, and etc,) and HTS(High Temperature Superconductor) to the cryogenic temperature. The monobloc Stirling cryocoolers with the rotary compressor are applicable to the cooling device for the compact mobile thermal imaging system, because the cryocoolers have the compact structure and light weight. The typical performance factors of the Stirling cryocooler are the cool-down time, cooling capacity at the desired temperature (80 K), the electric input power and COP. The above performance factors depend on the operating conditions such as the charging pressure of the helium gas, the thermal environment and etc.. In this study, the effects of the thermal environment (temperature of 241, 293, and 333 K) on the performance of the cryocooler were investigated by experiments. The results show the effects of the temperature of the thermal environment on the cooling capacity and input power.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.492-498
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• 2012

In this study, hydrodynamics such as solid circulation rate and voidage in the desulfurizer and the reaction characteristics of Zn-based solid sorbents were investigated using lab-scale high pressure and high temperature desulfurization process. The continuous HGD (Hot Gas Desulfurization) process consist of a fast fluidized bed type desulfurizer (6.2 m tall pipe of 0.015 m i.d), a bubbling fluidized bed type regenerator (1.6 m tall bed of 0.053 m i.d), a loop-seal and the pressure control valves. The solid circulation rate was measured by varying the slide-gate opening positions, the gas velocities and temperatures of the desulfurizer and the voidage in the desulfurizer was derived by the same way. At the same gas velocities and the same opening positions of the slide gate, the solid circulation rate, which was similar at the temperature of $300^{\circ}C$ and $550^{\circ}C$, was low at those temperatures compared with a room temperature. The voidage in the desulfurizer showed a fast fluidized bed type when the opening positions of the slide gate were 10~20% while that showed a turbulent fluidized bed type when those of slide gate were 30~40%. The reaction characteristics of Zn-based solid sorbent were investigated by different desulfurization temperatures at 20 atm in the continuous operation. The $H_2S$ removal efficiency tended to decrease below the desulfurization temperature of $450^{\circ}C$. Thus, the 10 hour continuous operation has been performed at the desulfurization temperature of $500^{\circ}C$ in order to maintain the high $H_2S$ removal efficiency. During 10 hour continuous operation, the $H_2S$ removal efficiency was above 99.99% because the $H_2S$ concentration after desulfurization was not detected at the inlet $H_2S$ concentration of 5,000 ppmv condition using UV analyzers (Radas2) and the detector tube (GASTEC) which lower detection limit is 1 ppmv.

• Applied Biological Chemistry
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• v.9
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• pp.29-33
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• 1968

Through an experiment with gas chromatography carried out using diethylene glycol succinate(DEGS) as the packing material of the column, we have obtained the correction factor between the weight ratio and the peak dimension of the saturated fatty acid methyl esters of C10, C12, C14, C16, and C18 and unsaturated fatty acid methyl esters of oleic acid, linoloic acid, and linolenic acid, employing the detector of thermal conductivity type. Quantitative analysis of the fatty acids contained in rice Bran oil was performed with the above correction factor and the results are as follows; 1. Main components were found to be palmitic acid, oleic acid sand linolenic acid. No trases of capric acid (C10) lauric acid (C10) were found. 2. It was confirmed that there were straight line relation between the logarism retention time of each fatty acid and the number of carbon of saturated fatty acid or the number of double bond of other fatty acids having the same number of carbon. 3. The correction factor became larger as to the number of carbon increased up to C18 in case of saturated fatty acids, end as for other fatty acids, and as for other fatty acids of the same carbon number, it became larger according as the number of double bond increased.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.37-44
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• 2014

Preservatives such as paraben, phenoxyethanol, and chlorphene are commonly used in cosmetics thanks to cheap price and good antiseptic effect. Recently, consumers' concerns about their possible toxicity and skin irritation forced them to be replaced with straight 1,2-alkanediols. However, as the alkanediols may also irritate skin, limited amount of them should be used in cosmetics. Three 1,2-alkanediols including 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol in cosmetics were analyzed simultaneously by gas chromatogrphy with flame ionization detector. As a result of method validation, the specificity was confirmed by the calibration curves of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol showing good linearity correlation coefficient of above 0.999 over the concentration range of $100{\sim}1,200{\mu}g/g$. The limit of detection (LOD) and quantification (LOQ) of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol were 31, 40, and $19{\mu}g/g$ and 98, 108, and $57{\mu}g/g$, respectively. The precision (Repeatability) of the amount in cosmetics showed less than 2.0%. Relative Standard Deviation (% RSD) and the Accuracy (% recovery) of the amount in cosmetics showed 99.3 ~ 103.3, 99.4 ~ 106.7, 97.5 ~ 107.3% respectively. As a result, simultaneous analysis of antimicrobial three 1,2-alkanediols in cosmetics were possible. This method can be utilized in accurate quantitative analysis of 1,2-alkanediols in cosmetics.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.129-140
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• 2007

CFC(CFC-12, CFC-11 and CFC-113) analytical system for air and water was constructed using a customized purge and trap extraction device and a gas chromatograph with an electron capture detector. Sampling methods of air and water for CFCs were also established. The analytical system was experimentally optimized to result in reproducibilities of triplicates less than 2% for current air samples and less than 5% for groundwater samples with CFC-12 concentration of 160 to 180 pg/kg, and verified with respect to the CFC system in USGS, which showed analytical results were in agreement within 10%. CFCs in air were monitored at three sites over 19-month period in the central part of South Korea, and the result indicates no significant local sources of CFCs in those areas. For groundwater in Jeju Island, CFCs were measured over a year with a two-month interval. The time-series data showed seasonal fluctuations which could be interpreted by the effect of recharge pulse derived from large amount of rainfall during monsoon period with a few month delay, which indicates high permeability of basaltic rocks in Jeju Island.

• Food Science of Animal Resources
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• v.28 no.2
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• pp.240-245
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• 2008

The consumption of foods containing trans fatty acids (TFAs) is a matter of concern at present. According to many studies, trans fatty acids (TFAs) may cause illnesses such as the coronary heart disease, diabetes mellitus, large intestine cancer, and breast cancer. They can also raise low density lipoprotein (LDL) cholesterol and reduce high density lipoprotein (HDL) cholesterol. TFAs can also inhibit the synthesis of phospholipids containing polyunsaturated fatty acids in arterial cells. As a consequence the Food and Drug Administration has deemed that saturated fatty acid, cholesterol and trans fatty acid levels be listed on food labels as of 2006. The Korea Food and Drug Administration also has required the listing of trans fatty acid content on food labels since 2007. The aim of this study was to determine the total lipid and trans fatty acid (TFA) contents in retort food, powdered milk, biscuit and pizza products. The number of samples examined were 2 retort food, 6 powdered milk, 7 biscuit and 3 pizza products. The extraction of total lipids in retort food and powdered milk followed the chloroform methanol method. The extraction of total lipids in biscuit and pizza was by the acid digestion method. All samples were analyzed by gas chromatography (GC) using a SP-2560 capillary column and a flame ionization detector. The TFA contents per 100g of sample were 1-2.8% (1.9%) in retort foods, 0.4-2.4% (1.37%) in powdered milk products, 0-2.9% (1.23%) in biscuits, and 2.8-3.45% (3.03%) in pizzas.

• Journal of Animal Science and Technology
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• v.53 no.5
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• pp.475-480
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• 2011

This study was conducted to investigate the effects of different feeding level of TDN (Total Digestible Nutrients) on the generation of main greenhouse gases such as carbon dioxide and methane in Hanwoo cows. The diet TDN (kg) adjusted to achieve ADG of 0 g/day (Control), 200 g/day (T1), and 400 g/day (T2) of the maintenance level TMR (Total Mixed Ration) delivered twice a day at 08:30 and 17:30. Cow are housed in a respiration chamber and the environmental temperature was maintained at $20^{\circ}C$. The gases were measured for 24 hours using the multi-detector instrument Mamos-300. The analyzed methane emissions of T1 and T2 were 33.5% and 69.6% higher than control, respectively, and the carbon dioxide emissions were 21.1% and 40.6% higher than control. Also, the hourly pattern of carbon dioxide and methane production were showed very similar emission. Gas production showed peak after 1 hour of feeding and this gap was wider in the afternoon than in the morning hours. It is clearly conducted that $CO_2$ and $CH_4$ emissions were different by limited intake levels of feed.

• Analytical Science and Technology
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• v.29 no.5
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• pp.242-247
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• 2016

This research aims to set up and validate methods of analyzing the methanol in wet wipes and verifies the analysis methods that applied to the wet wipes. We used Headspace (HS) Gas Chromatography (GC) - Flame Ionization Detector (FID) to the establish analysis method of methanol in wet wipes and optimized heating temperature, heating time, GC conditions with column. The result indicated that 3 mL of sample in 20 mL headspace vial can be equilibrated efficiently in headspace sampler at 70 ℃ for 10 min and sample was measured by GC with spli injection mode(10:1). The results show that linearity from 1 to 100 ppm was over R2 0.9995, precision was RSD 1.83 % and accuracy(recovery rate) was 105.44 (±1.05 %) on water matrix and wet wipes matrix removed non-woven fabric. Also, monitoring results of total 20 cosmetics on the market, from 0.00017 to 0.00156 % of methanol was detected from wet wipes.

• Geophysics and Geophysical Exploration
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• v.8 no.4
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• pp.270-279
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• 2005

Under the research project supported by Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), we have conducted the development of GPR systems for landmine detection. Until 2005, we have finished development of two prototype GPR systems, namely ALIS (Advanced Landmine Imaging System) and SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar). ALIS is a novel landmine detection sensor system combined with a metal detector and GPR. This is a hand-held equipment, which has a sensor position tracking system, and can visualize the sensor output in real time. In order to achieve the sensor tracking system, ALIS needs only one CCD camera attached on the sensor handle. The CCD image is superimposed with the GPR and metal detector signal, and the detection and identification of buried targets is quite easy and reliable. Field evaluation test of ALIS was conducted in December 2004 in Afghanistan, and we demonstrated that it can detect buried antipersonnel landmines, and can also discriminate metal fragments from landmines. SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar) is a machine mounted sensor system composed of B GPR and a metal detector. The GPR employs an array antenna for advanced signal processing for better subsurface imaging. SAR-GPR combined with synthetic aperture radar algorithm, can suppress clutter and can image buried objects in strongly inhomogeneous material. SAR-GPR is a stepped frequency radar system, whose RF component is a newly developed compact vector network analyzers. The size of the system is 30cm x 30cm x 30 cm, composed from six Vivaldi antennas and three vector network analyzers. The weight of the system is 17 kg, and it can be mounted on a robotic arm on a small unmanned vehicle. The field test of this system was carried out in March 2005 in Japan.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.243-251
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• 2020

In this study, we investigated pesticide residues in 207 agricultural products distributed by direct trade in the northern area of Gyeonggi Province. A total of 94 general agricultural products and 113 eco-friendly agricultural products collected from local grocers and cooperative stores were analyzed by multiresidue method for 263 pesticides using GC (gas chromatography)/ECD (electron capture detector), GC/NPD (nitrogen phosphorus detector), GC-MS/MS (tandem mass spectrometry), LC (liquid chromatography)/PDA (photodiode array detector), LC/FLD (fluorescence detector), LC-MS/MS. All samples showing pesticide residues were general agricultural products collected from local food stores. The pesticide residue levels of 14 samples (6.8%) were below the maximum residue limits (MRLs) and one of them (0.5%) exceeded the MRLs. Sixteen pesticides were detected from samples of the following produce items: spinach, young cabbage, perilla leaves, mallow, cucumber, chives and water dropwort. The safety of the detected pesticides was assessed by monitoring the daily intake estimate (EDI) and the daily intake allowance (ADI) based on the amount of pesticides detected. The ADI percentage range (the ratio of EDI to ADI) was 0.0134-61.6259% and there was no health risk connected with consuming agricultural products in which pesticide residues were detected.