• 태양에너지
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• 제11권2호
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• pp.34-40
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• 1991

Thermal stratification enhancement for the higher extraction efficiency of hot water storage tank was experimentally studied with transparent fiber glass cylindical tank($350{\ell}$, D=516mm, H=1680mm). Height to diameter ratio (H/D =1,2,3), flow rate(Q= 8,10,12LPM), inlet-outlet temperature differences(${\Delta}T=20,25,30^{\circ}C$), and geometry of inlet-outlet port were the parameters. In particular, three kind of distributors were used for geometry of inlet-outlet port. As a result, it was possible to get extraction efficiency of 95% by using the distributor having variable diameter but keeping a constant diameter of perforation. So it is recommendable to design the distributor so that the main pipe decrease in diameter toward the dead end.

• 한국해양바이오학회지
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• 제1권3호
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• pp.206-212
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• 2006

Supercritical carbon dioxide ($SCO_2$) extraction was investigated as a method for protein-sourcing material from squid viscera. To find the optimum conditions, the extraction of squid viscera using $SCO_2$ was performed under the conditions of temperature range from 35 to $45^{\circ}C$ and constant pressure 25 MPa using Hewlett-Packard 7680T. Also from result of SDS-PAGE, the protein denaturation was minimized when using $SCO_2$ extraction. And the major amino acids in the squid viscera were glutamic acid, aspartic acid, lysine, leucine, arginine, alanine, glycine, isoleucine, and valine. The main fatty acids from squid viscera were myristic acid, palmitic acid, stearic acid, heneicosanoic acid, palmitoleic acid, elaidic acid, oleic acid, eicosenoic acid, EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid).

• Mass Spectrometry Letters
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• 제12권4호
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• pp.186-191
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• 2021

A new method for chemical separation of light rare-earth elements (LREEs) using gas-pressurized extraction chromatography (GPEC) is described. GPEC is a microscale column chromatography system that features a constant flow of solvents, which is created by pressurized nitrogen gas. The separation column with a Teflon tubing was packed with LN resin. The proposed GPEC method facilitates production of lesser chemical wastes and faster separation owing to the use of low solvent volume compared to traditional column chromatography. We evaluated the separation of Ba, La, Ce, and Nd using various elution solvents. The column reproducibility of the proposed GPEC system ranged from 2.4% to 4.9% with RSDs of recoveries, and the column-to-column reproducibility ranged from 3.1% to 6.3% with RSDs of recoveries. The proposed technique is robust, and it can be useful for the fast separation of LREEs.

• 한국가스학회지
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• 제3권1호
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• pp.33-40
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• 1999

초임계 이산화탄소 및 보조용매를 사용하여 미역분말로부터 지방질의 추출특성을 조사하였다. 지방질의 추출속도는 미역입자가 작을수록, 압력이 높을수록, 온도가 낮을수록, 유량이 많을수록 증가하였으나, 지방질의 추출수율은 주어진 조건에서 거의 일정하였다. 본 연구의 실험범위에서 최적조건은 미역입자 300um, 초임계 이산화탄소의 온도 313K, 압력 13.8MPa 및 유량 30L/min이었고, 이 때 추출수율은 $1.45wt\%$이었다 동일농도의 보조용매를 사용한 경우 에탄을은 메탄올과 헥산보다 더 좋은 추출수율을 나타내었으며, 에탄올을 보조용매로 첨가한 경우는 이산화탄소만을 사용한 경우보다 2.21배의 추출수율의 상승효과가 있었다. 물질전달 매개변수 $k_fa$값은 초임계 이산화탄소만을 사용한 경우에 체류시간 또는 지방질의 평균농도가 감소함에 따라 증가하였으나, 에탄올을 보조용매로 사용한 경우는 반대 결과가 되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1337-1339
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• 2001

We have investigated the relation between the molecular weight distribution (MWD) of diffusible species and the recovery rate of hydrophobicity of room-temperature vulcanizing (RTV) silicone rubber (SIR) using solvent extraction at various temperatures. It was observed that the extract had a MWD ranging from a few hundreds g/mol to hundreds of thousands g/mol. By measuring the migration of siloxane to the extracted SIR surface through a thin carbon coating, the aspect of migration of diffusible species was observed as a real time plot, and the time constant of the migration was also calculated. According to the time dependence of IR-absorbance, the time constant was increased with the increase of MW of the extracts.

• International Journal of Computer Science & Network Security
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• 제23권9호
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• pp.141-149
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• 2023

Repacked mobile apps constitute about 78% of all malware of Android, and it greatly affects the technical ecosystem of Android. Although many methods exist for repacked app detection, most of them suffer from performance issues. In this manuscript, a novel method using the Constant Key Point Selection and Limited Binary Pattern (CKPS: LBP) Feature extraction-based Hashing is proposed for the identification of repacked android applications through the visual similarity, which is a notable feature of repacked applications. The results from the experiment prove that the proposed method can effectively detect the apps that are similar visually even that are even under the double fold content manipulations. From the experimental analysis, it proved that the proposed CKPS: LBP method has a better efficiency of detecting 1354 similar applications from a repository of 95124 applications and also the computational time was 0.91 seconds within which a user could get the decision of whether the app repacked. The overall efficiency of the proposed algorithm is 41% greater than the average of other methods, and the time complexity is found to have been reduced by 31%. The collision probability of the Hashes was 41% better than the average value of the other state of the art methods.

• 한국멀티미디어학회논문지
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• 제4권3호
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• pp.270-279
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• 2001

프로그램 수행 시간의 대부분이 루프 구조에서 소비되고 있기 때문에 루프 구조를 가진 순차 프로그램에서 병렬성을 추출하는 연구들이 많이 행해지고 있고 그 연구들은 하나의 프로시저 내 루프 구조의 변환에 치중되고 있다. 그러나 대부분의 프로그램들은 프로시저 간 잠재된 병렬성을 가지고 있다. 본 논문에서는 프로시저 호출을 가진 루프에서 병렬성 추출 방식을 제안한다. 프로시저 호출을 포함하는 루프의 병렬화는 대부분 자료종속거리가 uniform 형태의 코드에서만 집중되었다. 본 논문에서는 자료종속거리가 uniform 코드, nonuniform 코드 그리고 복합된(complex) 코드를 가진 프로그램에서 적용 가능한 알고리즘을 제시하였으며, 제안된 알고리즘과 loop extraction, loop embedding 그리고 procedure cloning 변환 방법을 CRAY-T3E로 성능 평가하였다. 성능평가 결과는 제안된 알고리즘이 효율적이라는 것을 보여준다.

• Korean Chemical Engineering Research
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• 제55권6호
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• pp.785-790
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• 2017

To collect zinc, Fe and Zn in spent pickling solution were extracted by using TBP (tributyl phosphate), and Zn was recovered from extracted solution to zinc oxalate particles by oxalic acid solution. The reusability of TBP solvent was also tested. The distribution coefficient of Zn was not affected by the concentration of Fe in spent pickling solution, almost constant with the values of 7.12~9.31 when extracted by TBP solvent. It was found that the extraction capacity of TBP solvent for Zn is higher than that for Fe. The extraction efficiency of Zn was higher than 95%, while most of Fe was left in aqueous phase. After the recovery, the used TBP solvent could be repeatedly reused for the extraction of Zn up to eight times. XRD analysis showed that zinc oxalate ($ZnC_2O_4$ $2H_2O$) was formed from the reaction of Zn-TBP and oxalic acid. From the results of SEM analysis, the formation of zinc oxalate particle was strongly affected by the concentration of oxalic acid. In summary, Zn in spent pickling solution was successfully separated and recovered with TBP solvent and oxalic acid solution, respectively.

• 한국식품과학회지
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• 제11권2호
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• pp.118-121
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• 1979

Under the experimental conditions of varying the thickness(2L cm) of ginseng disc and the bulk, concentration $(C_b.{\;}%)$, the experimental results were well coincided with those of the model which was set up by using the inter disc diffusion with constant diffusivity. It was therefore convinced that the extraction rate is controlled by the diffusion rate of ginseng components through the disc. The relationship between the diffusivity$(D{\;}cm^2/min)$ and the mean concentration (C %) of soluble ginseng components in the disc is as follows, $ln{\frac{C-C_{b0}}{C_i-C_{b0}}}=ln{\frac{8}{{\pi}^2}-{\frac{{\pi}^2D}{4L^2}{\theta}$ where $C_i(%)$ is the initial concentration of soluble ginseng components and $\theta$ (min.) is the extraction time.

• 공업화학
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• 제31권1호
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• pp.103-107
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• 2020

본 연구는 대부분의 산업부산물에 다량 포함되어 있는 칼슘이온을 자원화하기 위한 것으로 칼슘이온의 추출 및 분리 조건 별 특성을 확인하였다. 칼슘 추출원으로 산화칼슘, 추출용제로 염산을 사용했으며, 추출용제의 농도에 따른 추출량 및 추출액의 pH 변화 특성을 분석하였다. 추출용제의 농도가 높아짐에 따라 추출량은 증가하는 반면 추출액의 pH는 일정하게 유지되는 경향을 나타내었다. 추출된 칼슘이온을 분리하기 위하여 산·염기성 용액 주입하였으며, 침전물 발생 여부와 침전물의 형태에 대하여 분석하였다. 산·염기성 물질 중 황산, 수산화나트륨 용액을 칼슘추출액에 주입하였을 때 침전물이 발생하였으며 각각 CaSO₄, Ca(OH)₂ 형태로 분리되는 것을 확인할 수 있었다.