• Korean Journal of Pharmacognosy
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• v.32 no.3 s.126
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• pp.200-211
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• 2001

This study was carried out to determine the 11 organochlorine, 7 organophosphorus residual pesticides in 251 crude drugs. These residual pesticides in herbal drugs were extracted with acetonitrile and the extracts were cleaned up via LC-florisil solid phase extraction column. The prepared samples were assayed for pesticide residues using GC-ECD, NPD with capillary column and identified by GC-MSD. Recoveries were $63.9{\sim}111.5%$ in the organochlorine pesticides and $69.8{\sim}92.4%$ in the organophosphorus pesticides, and detection limits were $0.001{\sim}0.65\;ppm$ in the organochlorine pesticides and $0.0009{\sim}0.0074\;ppm$ in the organophosphorus pesticides. Pesticide residues were detected in 9 cases.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.26-35
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• 2020

BACKGROUND: Microbes that govern a unique biochemical process of oxidizing ammonia into dinitrogen gas, such as anaerobic ammonium oxidation (anammox) have been reported to play a pivotal role in agricultural soils and in oceanic environments. However, limited information for anammox bacterial abundance and distribution in the terrestrial habitats has been known. METHODS AND RESULTS: Phylogenetic and next-generation sequencing analyses of bacterial 16S rRNA gene were performed to examine potential anammox bacteria in paddy soils. Through clone libraries constructed by using the anammox bacteria-specific primers, some clones showed sequence similarities with Planctomycetes (87% to 99%) and anammox bacteria (94% to 95%). Microbial community analysis for the paddy soils by using Illumina Miseq sequencing of 16S rRNA gene at phylum level was dominated by unclassified Bacteria at 33.2 ± 7.6%, followed by Chloroflexi at 20.4 ± 2.0% and Acidobacteria at 17.0 ± 6.5%. Planctomycetes that anammox bacteria are belonged to was 1.5% (± 0.3) on average from the two paddy soils. CONCLUSION: We suggest evidence of anammox bacteria in the paddy soil. In addition to the relatively well-known microbial processes for nitrogen-cycle, anammox can be a potential contributor on the cycle in terrestrial environments such as paddy soils.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.15-23
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• 1999

A multiresidue, simple and rapid isolation technique known as matrix-solid phase dispersoin (MSPD) for the extraction and quantitative gas chromatographic/electron capture detection (GC/ECD) determination of 14 organochlorinated pesticides($\alpha$-BHC, ($\beta$-BHC, ($\gamma$-BHC, aldrin, dieldrin, endrin, heptachlor, ($\alpha$-endosulfan, ($\beta$-endosulfan, endosulfan sulfate, p,p'-DDE, o,p'-DDD, p,p'-DDD, p,p'-DDT) from meat fats. The 14 pesticide were fortified into meat fat(0.5g) and blend with 2g $C_{18}$, $C_{18}$meat fat matrix blend and 2g activated florisil comprise an extraction column from which the pesticides are eluted by adding 8ml acetonitrile. Then 2${\mu}\ell$ of the eluate is analyzed by GC/ECD. Unfortified blank controls are tested similarly. The eluate contained all the pesticide analytes and was free of interfering coextractants. Recovery rate(31.3-500ng/g) were ranged from 80$\pm$4% to 97$\pm$4%. Any organochlorinated pesticides were not detected in 120 samples of beef and pork collected from slaughter houses in Kyeonggi province.

• Korean Journal of Animal Reproduction
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• v.8 no.1
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• pp.10-15
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• 1984

This experiment was carried out to study the egg transports and distribution patterns in the oviducts of superovulated rabbits by administrations of PGF2$\alpha$. Group I (3 does) and Group II (3 does) were killed at 24 hours, 48 hours after mating, respectively. Group III (6 does0 received a single injection of 5mg/Kg of body weight of PGF2$\alpha$ at 24 hours after mating and killed at 4 hours after PGF2$\alpha$ administration. The oviducts were frozen in LN-gas, thawed using Howe's method, and cleared in Benzyl-Benzoate sol. using Orsini's technique. The location of the eggs and the AIJ. were identified using transmitted light from a dissecting microscope. The results obtained were as follows: 1. The average numbers of detected eggs from the oviduct were 28.6 (26-32), 26.0 (24-29), and 27.1 (22-34) in Group I, II, and III, respectively. 2. Detection rate was 88.7%, 76.4%, and 84.9% in Group I, II, and III, respectively. 3. The positionof all AIJ. was 44.2% to 55.0%(av. 49.5%) of the distance from the fimbriae to the UTJ.(Utero-Tubal Junction). 4. The changes of egg distribution patterns were as follows: Group I Ampulla : 52.3%, Isthmus : 47.7%, Group II Ampulla : 8.9%, Isthmus : 91.1% Group III Ampulla : 8.0% Isthmus : 92.0%.

• Analytical Science and Technology
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• v.15 no.3
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• pp.221-228
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• 2002

AMX is one of extremely high mutagenic compound produced from the reaction of the chlorine and the organic compound during the disinfection of tap water. In this paper, the chemical derivatization of MX with 2% sulfuric acid-methanol, iso-propanol, sec-butanol and n-butanol derivatives for the GC/MS analysis were tested or compared. Limit of detection for the EI and NCI mode were 25 pg and 1.25 pg, respectively. The good linear calibration curve was obtained the range of 25~2500 pg by EI and NCI

• Analytical Science and Technology
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• v.16 no.6
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• pp.458-465
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• 2003

The HS (headspace)-SPME (Solid phase microextraction) as rapid and simple method was performed for the determination of volatile fatty acids (VFAs) from the aqueous samples. In-fiber derivatization of VFAs with 1-Pyrenyldiazomethane (PDAM) was applied to improve their sensitivity of detection. In SPME procedure, typical parameters such as effects of solution pH, and salting out reagent and ultrasonication were investigated to improve the extraction efficiency. Based on the developed method, VFAs in wastewater samples were determined by gas chromatography / mass spectrometry-selected ion monitoring (GC/MS-SIM) mode.

• Mass Spectrometry Letters
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• v.3 no.4
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• pp.87-92
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• 2012

In this study, we explored a new approach for generating ions of organics and biomolecules using contactless atmospheric pressure ionization (C-API). That is, a tapered capillary (~20 cm) was connected to a syringe, which was coupled to a syringe pump for providing a given flow rate to introduce sample solution to the proximity of a mass spectrometer. The gas phase ions derived from analytes were readily formed in the capillary outlet, which was very close to the mass spectrometer (~1 mm). No external electric connection was applied on the capillary emitter. This setup is very simple, but it can function as an ion source. This approach can be readily used for the analysis of small molecules such as amino acids and large molecules such as peptides and proteins. The limit of the detection of this approach was estimated to be ~10 pM when using bradykinin as the sample. Thus, we believe that this approach should be very useful for being used as an alternative ion source because of its low cost, high sensitivity, simplicity, and ease of operation.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2195-2197
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• 1999

Electric breakdown in the liquid produces a spark channel. The energy input into the channel causes expansion of a vapor gas cavity. If the power of the discharge is high enough, this expansion is fast enough to produce a shock wave which propagates through the liquid to the subject of destruction. We focused our attention on the correlation between electric parameters and the characteristics of the flash caused by point to-point electrode discharge in the water. By varying firing voltage and gap length, we obtained the features of the flash : amplitude, pulse width, and so on. In this paper, We have known that there is a concrete interrelation between underwater firing voltage and photodiode output.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.8-11
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• 2003

We propose that when combustible burn with contain carbon, introduce fire detector with sensor of private-use detectable light energy as infrared and ultraviolet in energy of electromagnetic-wave type radiate from flame, method for correct discrimination to resemble fire produce false alarm of detector such as sun light, hot object radiation, are welding. This research using infrared sensor is pyroelectric infrared sensor based black body radiation theory. Ultraviolet sensor is uv Tron using gas multiplication effect to current discharge and photoelectric effect of metal. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research introduced UV/IR compound type flame detector and proposed method of false alarm reduced to resemble fire. The result propres the prevention and extinction of fire technique degree, certificated operation of detector.

• The Journal of the Acoustical Society of Korea
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• v.21 no.7
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• pp.614-623
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• 2002

In this paper, it was manufactured an interferometric optical fiber sensor and measured partial discharge acoustic signal caused by defect of power facilities such as power cables, transformers and gas insulation. Acrylic and aluminium mandrels wound with fiber-optic were chosen as optical fiber sensor, Sagnac and Mach-Zehnder interferometers were chosen to detect discharge acoustic signals. The two fiber optic interferometers were identified by using the PZT. Discharge experimentation set in the discharge imitation cell in oil tank and the discharge phenomena was generated. Based on the experimental result, to detect the discharge acoustic signal, Sagnac interferometer can detect stably the acoustic signal than the Mach-Zehnder interferometer. It is shown that Sagnac optical fiber sensor can detect the discharge acoustic signals effectively.