• Bulletin of the Korean Chemical Society
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• 제23권7호
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• pp.943-947
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• 2002

The two reactions between iron ion (Fe3+ ) and o-chlorophenylfluorone (o-CPF) and copper ion (Cu2+ ) and o-CPF are sensitive at pH 6 in the presence of Triton X-100. We have determined the formation constants of the complexes by the spectral correction technique. Because of the poor selectivity of o-CPF to metals, the competition coordination of only the iron ion from the Cu-o-CPF complex was found and applied to the selective detection of iron traces by the Selective Competition Coordination Determination (SCCD) approach.The analysis of several samples shows that the relative standard deviations are less than 5.0% and the recovery of iron ions between 94.5% and 106%.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1832-1838
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• 2006

The present paper is focused on sorption concentration of silver (I) on some complex-forming ion exchangers in the initial thiocyanate form and subsequent determination of Ag(I) in the phase of anion exchanger AN-25 by diffuse reflectance spectroscopy. The sorption and kinetic characteristics of the sorbents were investigated. The apparent stability constants of thiocyanate silver complexes in the ion exchanger phase were calculated. The sorption-spectroscopic method is proposed for Ag(I) determination in aqueous solutions. The calibration curve is linear in the concentration range of 10-200 mg/L (sample volume is 10.0 mL) and the detection limit is 2 $\mu$g/mL. The presence of $Na^+,\;K^+,\;Mg^{2+}$ (macrocomponents) as well as of Ni (II), Co (II), Cu (II) do not hinder the determination of silver (I).

• 마이크로전자및패키징학회지
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• 제9권4호
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• pp.31-34
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• 2002

For the mold die sticking mechanism, the major explanation is that the silica as a filler in EMC (epoxy molding compound) wears die surface to be roughened, which results in increase of adhesion strength. As the sticking behavior, however, showed strong dependency on the EMC models based on the experimental results from different semiconductor manufacturers, chemisorption or acid-base interaction is apt to be also functioning as major mechanisms. In this investigation, the plasma source ion implantation (PSII) using $O_2, N_2$, and $CF_4$ modifies sample surface to form a new dense layer and improve surface hardness, and change metal surface condition from hydrophilic to hydrophobic or vice versa. Through surface energy quantification by measuring contact angle and surface ion coupling state analysis by Auger, major governing mechanism for sticking issue was figured out to be a complex of mechanical and chemical factors.

• KSBB Journal
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• 제15권1호
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• pp.76-79
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• 2000

Complex, ill-defined mixtures of natural origin are often used as nutrients in the production of biological products through microbial fermentation. Product yields are affected by variation in these natural products. Yeast extract is a typical example of these natural products. Since it is a mixture of amino acids, peptides and nucleic acids, its composition is not well characterized. In this study, we investigated the properties of thiamine hydrochloride, riboflavin and pyridoxine hydrochlride in yeast extract by using a gel filtration chromatography, ion exchange chromatography and high performance liquid chromatography. Yeast extract solution was fractionated by gel filtration chromatography and ion exchange chromatography, and then, each fraction was analyzed by using a high performance liquid chromatography.

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.482-486
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• 1992

Ion-molecule reactions of acetylene and mixed acetylene-ammonia cluster ions are studied using an electron impact time-of-flight mass spectrometer. The present results clearly demonstrate that $(C_2H_2)_n^+$ cluster ion distribution represents a distinct magic number of n=3. The mass spectroscopic evidence for the enhanced structural stabilities of $[C_6H_4{\cdot}(NH_3)_m]^+$ (m=0-8) ions is also found along with the detection of mixed cluster $[(C_2H_2)_n{\cdot}(NH_3)_m]^+$ ions, which gives insight into the feasible structure of solvated ions. This is rationalized on the basis of the structural stability for acetylene clusters and the dissociation dynamics of the complex ion under the presence of solvent molecules.

• Archives of Pharmacal Research
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• 제5권2호
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• pp.71-77
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• 1982

Improvements in the analytical methodology used in the gas chromatographic/mass spectral analysis of phenolic compounds from cigarette smoke are described. For the direct analysis of crude samples, pyridine extraction and the glass capillary column GC was used for the separation of phenolics as trimethylsilyl derivativatives. The separations of cigarette smoke on Carbowax 20M and SE-54 wall coated open tubular columns are given. Improved methodology for the routine quantitation of the identified components using the computer-controlled multiple ion selection technique of MS presented. Considerations pertaining to routine analyses of a multitude of complex smoke samples are also discussed.

• 로봇학회논문지
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• 제18권1호
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• pp.88-92
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• 2023

Lithium-ion batteries are actively used in various industrial sites such as field robots, drones, and electric vehicles due to their high energy efficiency, light weight, long life span, and low self-discharge rate. When using a lithium-ion battery in a field, it is important to accurately estimate the SoC (State of Charge) of batteries to prevent damage. In recent years, SoC estimation using data-based artificial neural networks has been in the spotlight, but it has been difficult to deploy in the embedded board environment at the actual site because the computation is heavy and complex. To solve this problem, neural network lightening technologies such as network pruning have recently attracted attention. When pruning a neural network, the performance varies depending on which layer and how much pruning is performed. In this paper, we introduce an optimized pruning technique by improving the existing pruning method, and perform a comparative experiment to analyze the results.

• 대한화학회지
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• 제27권6호
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• pp.411-418
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• 1983

HF용액 또는 ${KHF}_2$용액에서 methylene blue의 양이온과 ${BF}_4^-$음이온이 이루는 착물을 1,2-dichloroethane으로 용매추출할 때, 용액 중에 존재하는 $F^-$와 ${HF}_2^-$음이온이 미치는 영향을 분광광도법으로 조사하였다.$F^-$ 이온은 $10^{-2}$의 비교적 진한 농도로 존재하더라도 methylene blue와 이온쌍을 이루지 않으므로 직접적인 영향을 주지 않았다. 그러나 ${HF}_2^-$이온은 ${BF}_4^-$이온과 경쟁적으로 methylene blue와 이온쌍을 이루어 BF4-이온과 함께 추출되는 것으로 보이고 25$^{\circ}C$ 에서 methylene blue-${HF}_2$ 이온쌍의 1,2-dichloroethane용매에 대한 추출상수, $K_{ext}$=8.5를 얻었다.

• 분석과학
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• 제8권1호
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• pp.79-84
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• 1995

Alverine에 대한 anionic counter ion으로서 acid red 97의 이용 가능성을 살펴보았다. PVC와 가소제의 비율이 같을 때 적절한 감응과 긴 수명을 나타내었으며, 검량선은 $1.0{\times}10^{-5}M$까지 직선성이었고 그 감응 기울기는 55.35mV/dec., 변동계수는 0.61이었다. Methylephedrine에 대하여는 -2.626, histidine에 대하여는 -2.216등의 선택계수를 보였고 pH 7.0~4.0에서 안정된 전위값을 얻을 수 있었다. $10^{-4}M$ 이하에서 20~30초 이내, 그 이상의 농도에서는 약 10초 이내에서 안정된 전위값을 얻을 수 있었다.

• 공업화학
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• 제8권1호
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• pp.23-28
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• 1997

활성탄에 의한 암모니아 구리착물의 흡착 특성에 대하여 연구하였다. 활성탄 비표면적을 BET 흡착장치에서 측정하였고, 암모니아수용액에서 암모니아 착물을 이용하여 Cu(II)이온 제거 특성과 활성탄에 의한 착물흡착에서 암모니아착물 형태에 대하여 연구하였다. 실험 결과 비표면적 크기는 mesh No.가 감소할 수록 증가하였고, 활성탄에 의한 Cu(II)이온 흡착은 pH 6 범위가 적합함을 알았다. 또한 암모니아수용액에서 암모니아 구리착물이 활성탄에 흡착되는 형태는 $[Cu(NH_3){_2}]^{2+}$와 $[Cu(NH_3){_3}]^{2+}$로 흡착됨을 알았으며, 암모니아 농도는 $2.25{\times}10^{-4}{\sim}2.25{\times}10^{-3}(mol/{\ell})$ 범위에서 검토하였다.