• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1009-1011
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• 2004

In the present work a very simple, sensitive and selective spectrophotometric method for the determination of nitrite in micellar media is described. The method is based on the color reaction of nitrite with p-nitroaniline in the presence of diphenylamine in acid media. In order to remove the extraction step, Triton X-100, a non-ionic surfactant was used as micellar media. The optimum reaction conditions such as acid concentration, reagents concentration and effect of time have been studied and the analytical characteristics of the method such as limit of detection, linear range and molar absorptivity have been obtained. The interference of some anions and cations was also tested. The method was applied to the determination of nitrite in real samples.

• Journal of information and communication convergence engineering
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• v.9 no.2
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• pp.161-165
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• 2011

Recently, According to increasing interest to original sound Karaoke instrument, MIDI type karaoke manufacturer attempt to make more cheap method instead of original recoding method. Separating technique for singing voice from music accompaniment is very useful in such equipment. We propose a system to separate singing voice from music accompaniment for stereo recordings. Our system consists of three stages. The first stage is a spectral change detector. The second stage classifies an input into vocal and non vocal portions by using GMM classifier. The last stage is a selective frequency separation stage. The results of removed by listening test from the results for computer based extraction simulation, spectrogram results show separation task successfully. Listening test with extracted MR from proposed system show vocal separating and removal task successfully.

• Environmental Analysis Health and Toxicology
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• v.15 no.1_2
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• pp.45-51
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• 2000

Analytical method of 4-nitrotoluene (4-NT) in water was developed by 9as chromatography/mass selective detector/selected ion monitoring (GC/MSD/SIM). 4-NT was extracted with diethyl ether. Organic layer was washed with 5 % sodium chloride solution. The influence of solvent and evaporation condition on extraction of 4-NT were examined. The retention time of 4-NT peak was 7.72 min. Coefficient of variation (CV) of 4-NT (ng) within day and day-to-day was ranged from 7.0 to 14.6% and from 7.7 to 20.8%, respectively. Recovery of 4-NT was ranged from 84 to 109%, and detection limit of 4-H was lese than 1 ng/㎖.

• Food Science and Biotechnology
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• v.14 no.2
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• pp.259-262
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• 2005

A fraction (CMEx-AH-${\beta}$) of water-soluble polysaccharides, showing selective antitumor activities, was isolated from the mycelia of solid cultured Agaricus blazei Murill by hot-water extraction, ethanol precipitation, and series of chromatography. Chemical characteristics of CMEx-AH-${\beta}$, were as follows: carbohydrate content, 48%; monosaccharide composition, Man:Glu:Gal (2:93:5); molecular weight, $2{\times}10^5$; uronic acid content, 6.2%. Fundamental structure of CMEx-AH-${\beta}$, was deduced as ${\beta}-(1\;{\rightarrow}\;6)$-D-glucan with ${\beta}-(1\;{\rightarrow}\;3)$-D-glucosidic side chains based on results of methylation and $^{13}C$ NMR spectroscopic analyses.

• Archives of Pharmacal Research
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• v.4 no.2
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• pp.85-90
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• 1981

A quantitative GC-MS spectrometric assay was used for the determination of residual N, N-dimethylaniline as a contaminant in commercial penicillin derivatives from various sources. The assay utilizes selective ion focusing to monitor in a GC effluent the molecular ions of DMA generated by electron impact ionization. This method includes dissolution of the sample in alkaline solution, extraction of organic base with cyclohexane and injection into GC-MS with a 3% OV-17 column. Levels of 50 ppb of DMA were easily measured with a coeffecient of varation less than 5 % and recoveries from spiked samples exceeded 97 %. The results of the determinations of DMA in various commercial penicillins were relatively free of this contaminant.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.374-376
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• 2000

음성인식 시스템에 사용하는 알고리즘 중에 하나인 DHMM은 코드북을 이용하여 음성의 프레임들에 대한 특징을 관측열로 추출하여 음성의 패턴에 대한 훈련과 인식을 수행하게 된다. 그러나 음성은 유성음과 무성음의 특징 차이가 많이 나게 되므로 하나의 코드북을 이용하게 되면 코드북 오차에 의하여 성질이 전혀 다른 코드북 인덱스를 DHMM의 관측열로 사용하게 된다. 본 논문에서는 음성의 유성음과 무성음에 대한 선별적인 작업을 통해 서로 다른 코드북을 만들어 관측열을 추출하고 선행 관측과 현 관측과의 거리 비교 연산을 통하여 관측의 시간축을 정규화한 관측열을 음성인식에 사용하였다. 본 논문에서 제시하는 인식 방법을 사용하여 실험한 결과, 기존의 인식 방법보다 5.33% 향상된 결과를 얻었다.

• Analytical Science and Technology
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• v.17 no.6
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• pp.476-480
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• 2004

A simple, rapid, reproducible and selective UV-Visible spectrophotometric method has been developed for determination of germanium in a week acid medium (pH = 3.0) in the presence of mandelic acid (MA) and malachite green (MG). A single extraction in chlorobenzene was used for the analysis. The germanium-MA ion association complex exhibits an absorption maximum at ${\lambda}_{max}=618nm$ with MG as counter ion and has an apparent molar absorptivtity of $1.313{\times}10^5L\;mol^{-1}\;cm^{-1}$. The values obtained by this UV-Visible spectrophotometric method are in good agreement with the values from inductively coupled plasma-mass spectrometer analysis.

• Journal of the Korean Applied Science and Technology
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• v.27 no.3
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• pp.273-281
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• 2010

Nickel recovery method was studied by the wet process from the catalyst used in hydrogenation process. Nickel content in waste catalyst was about 16%. At the waste catalyst leaching system by the alkaline solution, selective leaching of nickel was possible by amine complex formation reaction from ammonia water and ammonium chloride mixed leachate. The best leaching condition of nickel from mixed leachate was acquired at the condition of pH 8. LIX65N as chelating solvent extractant was used to recover nickel from alkaline leachate. The purity of recovered nickel was higher than 99.5%, and the whole quantity of nickel was recovered from amine complex.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.183-183
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• 2018

In this study, 5-bromo-2,9-bis(5,6-diphenyl-1,2,4-triazin-3-yl)-1,10-phenanthroline (5-bromo-Ph4-BTPhen) was synthesized and evaluated for its ability to remove major radionuclides ($Cs^+$, $Sr^{2+}$, and $Co^{2+}$). The synthesized ligand removed both $Sr^{2+}$ and $Co^{2+}$ from $1mg\;L^{-1}$ aqueous solutions with extraction efficiencies of up to 99% at neutral and alkaline pH. The $Sr^{2+}$ and $Co^{2+}$ removal efficiencies decreased as a consequence of the higher bonding strengths of competing metal ions to the N-donor atoms in the cavity of the ligand; competing divalent ions affected the $Sr^{2+}$ and $Co^{2+}$ removal efficiencies more than monovalent ions.

• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.340-346
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• 2021

The purpose of this study was to investigate the volatile flavor compounds of Ligularia stenocephala and Ligularia fischeri, edible wild plants. The volatile flavor compounds were isolated by the simultaneous distillation extraction method and analyzed by GC-MSD (gas chromatography-mass selective detector). Forty-eight volatile flavor compounds were identified in the extracts from L. stenocephala and the major compounds were sabinene, cis-ocimene, trans-caryophyllene, and β-elemene. Fifty-one volatile flavor compounds were identified in the extracts from L. fischeri and the major compounds were α-pinene, germacrene-D, transcaryophyllene, endo-1-bourbonanol and 1-limonene. The common volatile flavor compounds between two plants were transcaryophyllene, sabinene, β-elemene and β-cubebene etc. However, α-phellendrene and myrcene were identified in L. stenocephala, but were not identified in L. fischeri. However α-pinene, germacrene-D and limonene were identified in L. fischeri but were not identified in L. stenocephala.