• 제목/요약/키워드: Ion extraction

검색결과 605건 처리시간 0.023초

Uranium Analysis in Aqueous Samples by Selective Extraction and Photon-Electron Rejecting Alpha Liquid Scintillation $(PERALS^\circledR)$ Spectrometry

  • Shin, Hyun-Sang;Lee, Myung-Ho;Park, Geun-Sik;Lee, Chang-Woo
    • Nuclear Engineering and Technology
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    • 제31권5호
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    • pp.445-454
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    • 1999
  • This work describes the adaptation of extractive scintillation by URAE $X^{TM}$ with a photon-electron rejecting alpha liquid scintillation (PERAL $S^{)}$ spectrometer to the analysis of uranium in aqueous samples. The extraction efficiency of the system was evaluated under varing chemical conditions including pH, and sample-cocktail volume ratio. Isotopic information from the (PERAL $S^{)}$ spectrum of natural uranium was obtained using a curve fitting routine. Comparisons of the result with that obtained from alpha spectrometry method using ion implanted silicon detector showed good agreement.t.

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Detectio of Malonaldehyde-thiobarbituric Acid (MA-TBA) Complex by High Performance Liquid Chromatography(HPLC) in a Model System

  • Whang, Key
    • Preventive Nutrition and Food Science
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    • 제4권3호
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    • pp.167-170
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    • 1999
  • Various concentrations of malonaldehyde (MA) produced upon hydrolysis of 1, 1, 3,3-tetraethoxypropane (TEP) were reacted with 2-thiobarbituric acid (TBA)and th e contents of MA-TBA complex were measured both with spectrophotometer and high performance liquid chromatography (HPLC). As the concentrations of MA-TBA increased, their absorbances and the corresponding HPLC peak areas increased. The correlation coefficient between absorbances and HPLC peak areas of MA-TBA peaks from the other compounds and butanol extraction of the complex increased its recovery its recovery by 29.4% . Measurement of the content of MA-TBA complex for monitoring the development of lipid oxidation was proven to be successful with the use of high performance liquid chromatography.

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Tris(1,10-phenathroline) Fe(II) chelate에 의한 undecylenic acid의 흡광광도 정량법 (The spectrophotometric determination of undecylenic acid using tris (1,10-phenanthroline) Fe(II) chelate)

  • 강삼식;백남호
    • 약학회지
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    • 제16권4호
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    • pp.180-185
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    • 1972
  • A new spectrophotometric method was established for the determination of undecylenic acid. The method is based on the solvent extraction into nitrobenzene of the ion pair formed between tris(1,10-phenanthroline)Fe(II) chelate and the anion of undecylenic acid. The maximum absorbance of the extract in the organic phase was at 518nm. A maximum extraction was obtained at pH 9-11, when excess of at least 50-fold(molar) of the phenanthroline-Fe(II) chelate to undecylenic acid was present. The color intensity of the extracted species remained constant at room temperature for the several hours after separation of the organic layer. A linear relationship was obtained over the tested range of 5-20${\gamma}$/ml of undecylenic acid. The effect of several other fungicids on this method was investigated. The method was applied to the determination of undecylenic acid in preparations and the results were in good agreement with those added amounts.

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딥러닝과 특징 추출 기반 배터리 노화 상태 추정 방법 (Battery State-of-Health Estimation Method based on Deep-learning and Feature Engineering)

  • 장문석;이강석;배성우
    • 전력전자학회논문지
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    • 제27권4호
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    • pp.332-338
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    • 2022
  • This study proposes a battery state-of-health estimation method by applying a feature extraction technique. The technique that can improve estimation performance is the process of identifying and extracting meaningful data. To apply a data-driven-based aging state estimation method to batteries, health indicators are used as training data. However, limitations occur in extracting health indicators from charge/discharge cycles. This study proposes a deep-learning-based battery state-of-health estimation method that applies feature extraction techniques to compensate for this problem. According to the performance evaluation result of the proposed method, it has a low estimation error of 0.3887% based on an absolute error evaluation method.

Determination of 11 Phenolic Endocrine Disruptors using Gas Chromatography/Mass Spectrometry-Selected Ion Monitoring in Five Selected Wastewater Influents

  • Kim, Hyub
    • Environmental Engineering Research
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    • 제13권4호
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    • pp.216-223
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    • 2008
  • An efficient method for the simultaneous determination of eleven phenolic endocrine-disrupting chemicals (EDCs) present in wastewater influent samples was described. The 11 phenolic EDCs including alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) following two work-up methods for comparison; isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. The wastewater influent samples containing the 11 EDCs were adjusted to pH 2 with $H_2SO_4$ and then cleaned up with n-hexane. Next, they were subjected to solid-phase extraction (SPE) with XAD-4 resin and subsequently converted to isoBOC or TBDMS derivatives for sensitivity analysis with gas chromatography/mass spectrometry-selected ion monitoring (GC/MSSIM). Following isoBOC derivatization and TBDMS derivatization, the recoveries were 86.6-105.2% and 97.6-142.7%, the limits of quantitation (LOQ) for the 11 phenolic EDCs for SIM was 0.001-0.050 ng/mL and 0.003-0.050 ng/mL, and the SIM responses were linear with the correlation coefficient varying by 0.9717-0.9995 and 0.9842-0.9980, respectively. When these methods were applied to five selected wastewater influent samples, for isoBOC derivatization and TBDMS derivatization the ranges of concentration detected were 0.2-99.6 ng/mL and 0.4-147.4 ng/mL, respectively.

Antioxidant Activities of Various Solvent Extracts from Ginseng (Panax ginseng C.A. Meyer) Leaves

  • Kang, Ok-Ju
    • Preventive Nutrition and Food Science
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    • 제16권4호
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    • pp.321-327
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    • 2011
  • Water, methanol and ethanol extracts of ginseng leaves were assayed for total phenolics and flavonoids, ascorbic acid, cupric and ferrous ion chelating activities, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) assay and ABTS radical cation decolourization (TEAC) assay for their antioxidant properties. The ethanol extract of ginseng leaves contained significantly (p<0.05) higher amounts of total phenolics and flavonoids (600.57 and 1701 mg/100 g) than methanol (374.43 and 1512.64 mg/100 g) and water extracts (248.30 and 680.05 mg/100 g). Among solvent extracts of ginseng leaves, the ethanol extract showed the most powerful antioxidant activities. However, the ferrous ion chelating activity of ginseng leaf extracts were lower than the cupric ion chelating ability. These differences in concentrations of key antioxidants among various solvent extracts seemed to be responsible for their differences in antioxidant activities. These results suggest that ethanol extract of ginseng leaves has the most effective antioxidant capacity compared to the methanol and water extracts tested in the present study. Thus, it can be applied for the effective extraction of functional material from ginseng leaves for the usage of pharmaceutical and/or food industries.

환경시료로부터 미량 페놀류의 분석을 위한 isoButoxycarbonyl 유도체화 분석방법 적용 및 최적화 (Application and Optimization of the IsoButoxycarbonyl Derivatization method to the Analysis of Trace Level Phenols in Environmental Samples)

  • 김협;홍종기;김용화;김경례
    • Environmental Analysis Health and Toxicology
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    • 제17권1호
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    • pp.37-51
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    • 2002
  • Eleven phenols including two chlorophenols, eight alkylphenols and bisphenol A were derivatized with isobutylchloroformate to form their isobutoxycarbonyl derivatives. Standard phenol mixture was concentrated for the isobutoxycarbonyl (isoBOC) derivatization and analysed by gas chromatography/mass spectrometry (GC/MS). The recoveries of the derivatization method of alkylphenols, chlorophenols, and bisphenol A were calculated by gas chromatography/mass spectrometry-selected ion monitoring mode using two work-up methods for comparison; shaking and heating method. The linear detector responses were obtained in the concentration range of 5∼400 ng, with correlation coefficients varying from 0.9755∼0.9981. Recoveries of the alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode using two work-up methods for comparison ; the US-EPA method and the isoBOC derivatization method, Eleven phenols in water samples were extracted with dichloromethane and then concentrated. Also, solid-phase extraction (SPE) with XAD-4 and subsequent conversion to isobutoxycarbonyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The recoveries were 85.1∼109.9% and 90.3∼126.6% for the US-EPA method and the isoBOC.

Versatilities of Calix[4]pyrrole Based Anion Receptors

  • Lee, Chang-Hee
    • Bulletin of the Korean Chemical Society
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    • 제32권3호
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    • pp.768-778
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    • 2011
  • Calixpyrroles and related macrocycles are non-planer synthetic anion receptors that have attracted considerable attentions in recent years. Although the synthesis of calix[4]pyrrole (known as meso-octamethylporphyrinogen) was reported more than 100 years ago, the anion binding properties were first discovered in 1996. The simple calix[4]pyrroles can be synthesized in single step in high yield by condensation of pyrrole with acetone. The compounds showed preferential binding for halide anions including fluoride, phosphate, carboxylate, and chloride in organic media. Efforts to improve the anion affinity of calix[4]pyrrole and to enhance its selectivity have led to the synthesis of a variety of new calixpyrrole derivatives. Among the various modifications, introduction of straps on one side of the calix[4]pyrroles are the most effective. Incorporation of aromatic rings other than pyrroles also exhibited interesting binding behaviour. Introduction of signalling units as part of the strapping element enable to detect the anions on chromogenic or fluorogenic fashion. Finding of the anion transport properties across the membrane and cytotoxic effects of the calix[4]pyrroles open new window for calixpyrrole-related research. The polymer-incorporated systems have also been employed as anion complexants in solvent-solvent extraction. These old, yet easy-to-make macrocycles have well advanced more recently with the discovery of the ion-pair complexation properties. In this review, the synthetic developments and anion binding properties of calixpyrroles for the last decades will be discussed and will cover the advances in calixpyrrole chemistry.

JFET 영역의 이중이온 주입법을 이용한 Power MOSFET의 온저항 특성에 관한 연구 (Properties of Reducing On-resistance for JFET Region in Power MOSFET by Double Ion Implantation)

  • 김기현;김정한;박태수;정은식;양창헌
    • 한국전기전자재료학회논문지
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    • 제28권4호
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    • pp.213-217
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    • 2015
  • Device model parameters are very important for accurate estimation of electrical performances in devices, integrated circuits and their systems. There are a large number of methods for extraction of model parameters in power MOSFETs. For high efficiency, design is important considerations of a power MOSFET with high-voltage applications in consumer electronics. Meanwhile, it was proposed that the efficiency of a MOSFET can be enhanced by conducting JFET region double implant to reduce the On-resistance of the transistor. This paper reports the effects of JFET region double implant on the electrical properties and the decreasing On-resistance of the MOSFET. Experimental results show that the 1st JFET region implant diffuse can enhance the On-resistance by decreasing the ion concentration due to the surface and reduce the On-resistance by implanting the 2nd Phosphorus to the surface JFET region.

An Investigation on the Extraction and Quantitation of a Hexavalent Chromium in Acrylonitrile Butadiene Styrene Copolymer (ABS) and Printed Circuit Board (PCB) by Ion Chromatography Coupled with Inductively Coupled Plasma Atomic Emission Spectrometry

  • Nam, Sang-Ho;Kim, Yu-Na
    • Bulletin of the Korean Chemical Society
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    • 제33권6호
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    • pp.1967-1971
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    • 2012
  • A hexavalent chromium (Cr (VI)) is one of the hazardous substances regulated by the RoHS. The determination of Cr (VI) in various polymers and printed circuit board (PCB) has been very important. In this study, the three different analytical methods were investigated for the determination of a hexavalent chromium in Acrylonitrile Butadiene Styrene copolymer (ABS) and PCB. The results by three analytical methods were obtained and compared. An analytical method by UV-Visible spectrometer has been generally used for the determination of Cr (VI) in a sample, but a hexavalent chromium should complex with diphenylcarbazide for the detection in the method. The complexation did make an adverse effect on the quantitative analysis of Cr (VI) in ABS. The analytical method using diphenylcarbazide was also not applicable to printed circuit board (PCB) because PCB contained lots of irons. The irons interfered with the analysis of hexavalent chromium because those also could complex with diphenylcarbazide. In this study, hexavalent chromiums in PCB have been separated by ion chromatography (IC), then directly and selectively detected by inductively coupled plasma atomic emission spectrometry (ICP-AES). The quantity of Cr (VI) in PCB was 0.1 mg/kg.