• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.692-699
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• 2012

The aim of the present study is to explore the possibility of utilizing loess and fly ash as well as activated carbon for the adsorptive removal of PCBs in transformer oil. Here, we investigated the effect of various factors such as temperature (5, 25, 55), contact time (30 min-3 day) and adsorbent does (1, 2.5, 5, 10 g) in detail. It was found that PCBs adsorption rate from transformer oil by activated carbon is more favored than loess at the equilibrium time of 60 minutes. The equilibrium data for both activated carbon and loess is fitted well to the Freundlich isotherm model. The rate constant and activation energy of PCBs adsorption in transformer oil on each adsorbent was analyzed by fitting a kinetic model at 5, 25 and $55^{\circ}C$. From the thermodynamic parameters, the PCBs adsorption process for transformer oil/activated carbon and loess system is spontaneous and endothermic in nature.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.700-705
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• 2012

The present study is to explore the possibility of utilizing loess and fly ash as well as activated carbon for the adsorptive removal of T-N and T-P in water. Here, we investigated adsorption efficiency and Freundlich constants k and 1/n of each adsorbent. It was found that fly ash has not adsorptive capability for both T-N and T-P in water. Adsorption of T-N from water by loess has not occurred, but showed that adsorption efficiency for T-P reached approximately 57.5% at equilibrium time of 24 hr and room temperature. Activated carbon was shown to be an effective adsorbent for adsorption of T-N from water. Freundlich constant 1/n value of activated carbon represented that adsorptive capability of activated carbon is almost equivalent to loess.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.440-445
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• 2019

It has developed a method that can recover efficiently the reproducible resources from the vehicle waste lithium second battery module. Module cell consists of copper thin film, aluminum thin film and diaphragm made with polymer between these thin films. Cell was disassembled completely without any damage in glove box and through several steps. Preferentially, cathode active material was separated from aluminum thin film at heat treatment of 400 ℃. The retrieved cathode active material was then obtained as high purity after calcining at 800 ℃ to remove residual carbon. Based on this study, it was found that rare metals such as Co, Ni, Mn and Li made up of cathode active material could recover above 80% from aluminum thin film.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.446-452
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• 2019

We have developed a method that can leach Co, Mn, and Ni in the cathode active material safely using lactic acid. When cathode active material was leached by lactic acid, lactic acid showed the highest efficiency at 2 N than 1 N and above 4 N concentration. When the cathode active material was added incrementally into the solution of lactic acid, the maximum solubility was 30 g/L at 2 N concentration. Oxalic acid was added in the solution of lactic acid and it showed that rare metals represent the most economical recovery efficiency at 4 g/L. Based on this study, it was found that the optimal condition for recovery of rare metals from cathode active material is oxalic acid : cathode active material = 7 : 1 as a ratio of weight. In addition, it was observed that the precipitate produced by oxalic acid is a polynuclear crystalline material bonded with 3 components of Co, Ni, and Mn.

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.219-232
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• 1997

치아는 성별과 연령의 추정은 물론 혈형 검사와 유전자 검사까지 가능하게 하는 중요한 법의치과학적 자료이다 대부분 치아를 이용한 연구는 핵 DNA가 들어있는 치수에서의 연구로 치수내에는 풍부한 혈액 및 세포가 분포해 있어 핵 DNA가 다량 함유되어 있다. 그러나 순수 상아질에는 핵이 없고 따라서 핵 DNA도 없는 것으로 알려졌지만 치수내에 존재하는 핵 DNA가 상아세관을 통하여 상아질내로 침투할 가능성이 있고 실제 근관치료가 되어 있는 무수치를 감정하게 되는 경우도 있다. 본 연구에서는 이러한 치아중에서도 근관치료를 받은 무수치에서 개인식별에 활용되는 유전자가 검출되는지 여부를 확인하고자 하였다. 40개의 근관치료된 치아상아질에서 DNA출 추출하고 중합효소반응을 이용하여 증폭절편다형(Amp-FLPs)을 실시하고 X-Y homologous amelogenin gene과 STR 유전좌위 F13A01, LPL를 검색하여 다음과 같은 결과를 얻었다. 1. 40개의 근관치료된 치아중 19개에서 DNA가 추출되었다. 2. X-Y homologous amelogenin gene 검색으로 40개의 근관치료된 치아에서 21의 남자 치아중 5개, 19개의 여자치아중 7개 등 모두 12개 치아에서 성별검사가 가능하였다. 3. F13A01 유전자는 43개의 근관치료된 치아중 6개의 치아에서 검색되었으며, 4개의 대립유전자 및 5개의 유전자형을 관찰하였다. 4. LPL_유전자는 40개의 근관치료된 치아중 7개의 치아에서 검색되었으며, 3개의 대립유전자 및 3개의 유건자형을 관찰하였다. 이상의 결과를 종합하여 볼 때 근관치료된 치아상아질에서 중합효소반응을 이용한 성별검사 및 STR 유전자위의 검색은 일부 치아에서만 가능하였으나, 근관치료된 치아들도 개인식별을 위한 법의치과학적 자료로서 유용할 것으로 사료된다.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.129-138
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• 2011

Performance changes of an anode-supported tubular SOFC including current collectors are analyzed at different current collecting methods using numerical simulation. From the two dimensional numerical model of the solid oxide fuel cell with nickel felts as anodic current collectors and silver wires as cathodic ones, the performance curves and the distributions of temperature, concentration, current density are obtained. Also, the voltage loss of the cell is divided into three parts: activation loss, concentration loss and ohmic loss. The results show that the performance change of the cell is dominantly influenced by the ohmic loss. Although the temperature and concentration distributions are different, the total activation loss and concentration loss are nearly same. And the ohmic loss is divided into each parts of the cell components. The ohmic loss of the anodic current collectorreaches about 60~80% of the cell's total ohmic loss. Therefore, the reduction of the ohmic loss of the anodic current collector is very important for stack power enhancement. It is also recommended that the load should be connected to the both ends of the anodic current collector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.5C
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• pp.454-464
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• 2002

In the ATM-PON (Asynchronous Transfer Mode-Passive Optical Network), the downstream cell transmitted by an OLT is broadcast to all ONUs. The ONU receives selectively its own cells by VP filtering. On the other hand, the upstream cell can be transmitted by ONU in the case of receiving a grant from the OLT. After providing the grant to an ONU, the OLT expects the arrival of a cell after an elapse of the equalized round trip delay. ITU-T G.983.1 recommends that one bit error is allowed between the expected arrival time and the actual arrival time at the OLT. Because the ONU processes the different delay to each type of grant (ranging, user cell, and mimi-slot grant), it is not simple to design the transmission part of ONU. In this paper, we implement a grant processor which provides the delay accurately in the ONU TC chip with the FPGA. For the given equalized delay, it deals with the delay for the cell, the byte, and the bit unit by using the shift register, the byte counter, and the D flip-flop, respectively. We verify the operation of the grant processor by the time simulation and the measurement of the optical board output.

• Journal of the Korean Chemical Society
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• v.61 no.5
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• pp.238-243
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• 2017

In this study, water treatment sludge carbonized with $400^{\circ}C$ was tested as an adsorbent for the removal of Pb and Cd in water. The carbonized sludge was characterized by thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), and surface area analysis. Carbonized sludge exhibited much higher specific surface area and total pore volume than water treatment sludge itself. In batch-type adsorption process, carbonized sludge represented better adsorption performance for Pb than Cd, achieving 90~98% at the concentrations conducted in the experiments. Equilibrium data of adsorption were analyzed using the Freundlich and Langmuir isotherm models. It was seen that both Freundlich and Langmuir isotherms have correlation coefficient $R^2$ value larger than 0.95. The results of studies indicated that carbonized water treatment sludge by heat treatment could be used as an efficient adsorbent for the removal of Pb and Cd from water.

• Korean Journal of Human Ecology
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• v.5 no.1
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• pp.14-27
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• 2002

The purpose of this study is to identify the ritual dress used by the 12 religious bodies of Dankun followers to help understand the teachings of these currently operating religious groups in Korea. The findings from the survey and related literatures are used to analyze the characteristics of these ritual dresses in terms of their items, construction, form, and color. The results of the study are as follows: first, most of the religious groups of Dankun followers have established the code for ritual dresses and they are named as 'chaebok'(제복, sacrificial robes), 'yebok'(예복, ceremonial dress), 'chungbok'(정복, formal attire), 'pubbok'(법복, Buddhist formal dress), or 'tobok'(도복, Taoist garments). The official headgear is usually named as 'chaemo'(제모), 'soogun'(수건), 'moja'(모자), or 'yoogun'(유건, 儒巾). Though, there are some groups which do not use any specific names for headgear. Second, the ritual dresses of most groups are composed of the 'hanbok'(한복,韓服) or usual Western-style dress, a traditional outer wear, 'po'(포,袍), and a headgear, as a basic attire. Third, the traditional 'hanbok' is worn as a base garment and an outer wear is worn above. The different types of outer wear are used: mostly 'chaksu jueui jikyoun po'(착수주의직령포, 窄袖周衣直領袍) for men and 'kwangsu jikyoung po'(광수직령포, 廣袖直領袍) and other various styles for women. The headgear from the ancient times are worn by both men and women. Fourth, the most frequently-used color for ritual dress is white for both men and women's dress. The colors from the Yin and Yang ideology are also used in the ritual dresses. Finally, the kinds of materials are not considered as an important element for the ritual dresses.

• Journal of the Korean Chemical Society
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• v.62 no.6
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• pp.433-440
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• 2018

The pyrolysis has been universally applied to recycle the waste artificial marble. However, the existing heat treatment equipment has relatively low heat transfer efficiency into the inner part of the waste artificial marble. Besides, it leads to unnecessary excessive gas during the partial carbonization of the polymethyl methacrylate (PMMA) and raises the risk of fire due to heat at an extremely high temperature. This study suggests the process of pyrolysis at the formation state after adding the starch to waste artificial marble to overcome above-mentioned problems. As the result of experiments, this method showed that the pyrolysis of waste artificial marble was greatly improved at comparatively low temperature condition of $350^{\circ}C$. Moreover, it also manifested the effect on securing the stability and energy savings necessary for the recovery of methyl methacrylate (MMA) and ${\alpha}$-alumina (${\alpha}-Al_2O_3$).