• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1073-1080
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• 2018

There are several types of petroleum products used for the fuel oil, according to their respective quality standards, grades and usage. Depending on the degree of oil tax rate by country, even the same petroleum products will have price gap. The illegal mixing of cheap petroleum products, which are subject to the lower tax rate, with relatively expensive transportation fuel causes problems such as tax evasion, environmental pollution and vehicle breakdown. In order to prevent illicit production and mixing of these different petroleum products, a small amount of markers are legally added to specific petroleum products. In Korea, markers are introduced and used to prevent illegal activity that kerosene used as fuel for house and commercial boiler are mixed with automotive diesel fuels, and marker contents are analyzed to use UV-Vis spectrophotometer and high performance liquid chromatography (HPLC). In this study, we have developed a method to qualitatively and quantitatively determine the marker added to petroleum products by gas chromatography-mass spectrometry (GC-MS) without adding developing reagent or sample pre-treatments.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1260-1268
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• 2018

To improve fuel performance and specific characteristics of long storage and moving through fuel systems additives should be added in kerosene type aviation turbine fuel (AVTUR) such as antioxidant, fuel system icing inhibitor (FSII), electric conductivity improvers and so on. The dosage of additives has to be analyzed qualitatively and quantitatively due to inspect the quality of abnormal fuel and distinguish other petroleum products. Multi-dimensional GC-MS (MDGC-MS) with Deans switching technique are applied the determination of antioxidant and FSII, which are added with AVTUR containing complex mixture of hydrocarbons. Antioxidant and FSII in the range of 2.5-20 mg/L was quantitatively and qualitatively analyzed using MDGC-MS and the detection limit was about twice as low as that of the 1-dimensional GC-MS results. The method in this study has been higher peak resolution compared with GC-MS and could be simultaneously analyzed different two additives without sample pre-treatment.

• Journal of Climate Change Research
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• v.2 no.4
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• pp.309-316
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• 2011

The study evaluated the loss rate of carbon dioxide, which is the prevalent greenhouse gas, according to the method of keeping specimens using standard gases. In order to examine the difference generated by a bag of storing specimens, it checked the loss rate according to concentration and time by making a 2nd set of standard gases in a Tedlar bag and an Aluminium bag. The containers lost gases at a rate of 5% or more after 6 day, and 10% or more after 15 days in both bags. In time, it was confirmed that the loss rate of the Aluminium bag was higher than that of the Tedlar bag. Specifically, there was no significant difference between the two bags after 12 days had passed, but by the 15th day, it was confirmed that the loss in an Aluminium bag was more severe than that in the Tedlar bag. The study went on to check the relations between the humidity in storage and the loss rate. The results showed that there was no significant effect of humidity on the loss rate until 72 hours had passed, when the loss rate in the Tedlar bag with high humidity was about 5% higher than that of the Tedlar bag in dry conditions. This study examined the loss rate of carbon dioxide, a typical greenhouse gas. It is important to note that the loss rate was determined by calculating highly reliable carbon dioxide emission and emission coefficient data, with consideration to the method of keeping specimens.

• Journal of agricultural medicine and community health
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• v.44 no.1
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• pp.1-10
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• 2019

Objectives: This study aimed to assess the status of Scrub typhus, Leptospirosis and HFRS(hemorrhagic fever with renal syndrome) among farmers with febrile illness. Methods: We involved a total of 841 farmers who had febrile illness(508 and 333 village residents were, respectively, three and four district of Gyeongju city) selected during autumn of 2014 and 2015. Data were collected by survey questionnaires and blood sample examination. Results: Serum response rate for Scrub typhus and Leptospirosis was 1.5% each and 1.9% for HFRS. Serum response rate for Scrub typhus was significantly higher for tick-bite cases(38.5%), while Leptospirosis was significantly higher for those who were in fruit-planting work(23.1%). Similarly, serum response rate was significantly higher for HFRS who were working in venyl green house work(25.0%). Conclusions: Government authority should develop effective and efficient preventive strategies to create awareness of infectious diseases among farmers. Extending information, education and communication be reached to farmers that could change their perception and help early diagnosis and treatment and reduce the disease burden and its complication.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.339-346
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• 2018

Cyanazine is a member of the triazine family of herbicides. Cyanazine is used as a pre- and post-emergence herbicide for the control of annual grasses and broadleaf weeds. This experiment was conducted to establish a determination method for cyanazine, as domestic unregistered pesticide, residue in major agricultural commodities using HPLC-DAD/MS. Cyanazine was extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice and soybean. The extract was diluted with saline water and partitioned to dichloromethane for remove polar extractive in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized florisil column chromatography. On a $C_{18}$ column in HPLC, cyanazine was successfully separated from co-extractives of sample, and sensitively quantitated by diode array detection at 220 nm. Accuracy and precision of the proposed method was validated by the recovery experiment on every major agricultural commodity samples fortified with cyanazine at 3 concentration levels per agricultural commodity in each triplication. Mean recoveries were ranged from 83.6 to 93.3% in five major representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation(LOQ) of cyanazine was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring(SIM) technique was also provided to clearly identify the suspected residue.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.136-141
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• 2011

This study was conducted to confirm the application as ingredients of cosmetics through an examination of the function for anti-cancer and anti-microbial of the fraction isolated from Pyrus ussuriensis leaves. The dried leaf of P. ussuriensis were extracted with acetone-$H_{2}O$ (6:4, v/v), concentrated and fractionated with the upper layer of acetone on a separatory funnel. Each fraction was freeze dried, then a portion of acetone soluble powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol as eluents and also used the MIC-gel using a series of aqueous methanol as developing solvent. The isolated compounds were identified by silica-gel TLC. The growth inhibition activity was measured using the MTT assay by the mouse meltioma (B16F10) cell. The cancer cell growth inhibition rate of fractions isolated from P. ussuriensis leaf was 80%. In anti-microbial activity test, the fraction of P. ussuriensis with 0.25 mg/disc resulted in the clear zone of 1.3 cm and 2 cm for Staphylococcus aureus and S. epidermidis of gram positive bacillus, respectively. In Escherichia coli of gram negative bacillus, the fraction with 0.5 mg/disc resulted in the clear zone of 1.1 cm~1.5 cm each fraction. From these results, we confirmed that acetate fraction of P. ussuriensis has a great potential as a natural ingredients with a anti-cancer and anti-microbial source.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.344-354
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• 2020

Identification of the target species of 2-MIB (2-methyllisoborneol) production is crucial in the management of off-flavor problem in the freshwater system. This study was conducted to identify 2-MIB-producing Pseudanabaena strains occurring in the North Han River system using molecular genetic method. Eleven phenotypes of Pseudanabaena were isolated from several mainstream sites of the North Han River, including Sambong-ri, Joam-myun, and Lake Uiam areas. Despite of morphological similarity of the strains, the phylogenetic analysis using 16S rDNA classified them into different species with low genetic similarity (40~55%). Isolated Pseudanabaena strains were converged to four species; Pseudanabaena cinerea, P. yagii, P. mucicola, and P. redekei. Among them, the 2-MIB synthesizing gene (mibC) was detected in P. cinerea, P. yagii, and P. redekei. However, actual 2-MIB production was detected only in P. cinerea and P. redekei based on gas chromatography analysis. This study is the first report of the molecular identification of Pseudanabaena strains and their 2-MIB production potential in Korea. The results of this study provides an evidence of species diversity of Pseudanabaena occurring in the North Han River.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.393-398
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• 2020

The blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae), is an emerging pest on cultivated blueberries in Korea. To develop a sensitive tool for monitoring this pest in blueberry orchards, we compared the attractiveness of host plant volatiles and sex pheromone to D. oxycoccana adults. We performed gas chromatography-mass spectrometry (GC-MS) analysis of solid-phase microextraction (SPME)-collected volatiles that were released from blueberry ('Darrow' cultivar). The analysis revealed two major volatiles, cinnamaldehyde and cinnamyl alcohol from flowers; and three major volatiles, β-caryophyllene, germacrene D, and α-farnesene from shoots and young fruits. In field tests conducted in Gunsan, Korea in 2019, commercialized cinnamaldehyde, cinnamyl alcohol, β-caryophyllene, and α-farnesene, used singly or in quaternary combination, were unattractive to the blueberry gall midge. However, traps baited with the known sex pheromone (2R,14R)-2,14-diacetoxyheptadecane attracted significantly more males than the treatments with plant volatiles or the control. No synergistic effect was observed between sex pheromone and plant volatiles. Male D. oxycoccana were captured in the pheromone traps from May to August, with three peaks in mid-May, late June, and late July in Gunsan blueberry fields in 2020.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.35-44
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• 2004

The water soluble fractions(WSF) from Japanese larch wood were isolated, purified by anion exchange resin and Sephadex gel filtration and identified its chemical structure by means of periodate oxidation and methylation reactions. Its major components are arabinose and galactose (1 : 3.4). Based on the results of periodate oxidation, methylation and gas chromatographic analysis of purified WSF, main chain is composed of β-1,3-glycosidic linkage among D-galactopyranoses, and two different side chains; β-1,6-glycosidic linkage among 2-3 units of D-galactopyranoses and β-1,6-glycosidic linkage between 1-2 units of D-galactopyranose and L-arabinopyranose. Addition of WSF to culture media of oak mushroom (Lentinula edodes) accelerated the mycelial growth. In the case of PDA cultures, 2 percent addition of WSF in Sanlim No. 6 strain and 4 percent of WSF in Mok-H strain mostly enhanced the mycelial growth of the mushroom. In the case of sawdust cultures, 4 percent addition of WSF in two strains showed the best mycelial growth. High percentages addition of WSF inhibited mycelial growth of the mushroom. Mushroom production was increased with addition of WSF. By the addition of WSF, ergosterol contents in the media were quite high at the colonized stage and rapidly increased at the fruiting stage. Therefore the ergosterol content could be utilized as an indicator to evaluate the culture maturity for the mushroom fruiting.

• Clean Technology
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• v.15 no.1
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• pp.9-15
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• 2009

Catalytic hydrodechlorination of PCBs (polychlorinated biphenyls) included in the transformer oil was carried out to detoxify PCBs and to recycle the treated oil. Catalysts such as 0.98 wt% Pt and 0.79 wt% Pd on ${\gamma}$-alumina (${\gamma}-Al_2O_3$) support, 12.8 wt% Ni on ${\gamma}-Al_2O_3$, and 57.6 wt% Ni on silica-alumina ($SiO_2-Al_2O_3$) support were used for the catalytic hydrodechlorination. Various supercritical fluids such as carbon dioxide, propane and isobutane were used as reaction media. The effects of reaction temperature, reaction time, catalysts, and supercritical fluids on the catalytic hydrodechlorination were examined in detail. The detoxification degree increased in the order of Ni > Pd > Pt. This is possibly due to higher metal loading and larger metal size of the Ni catalyst. Below $175^{\circ}C,\;scCO_2$ was found as the most effective reaction media for the catalytic hydrodechlorination of PCBs included in the transformer oil.