• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.04a
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• pp.68-76
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• 1991

최근 열간압연의 공정이 단순하고 회수율이높은 CC재 (연속 주조재)가 IC재 (Ingot 주조재)에 비해 냉간압연 재료의 주종을 이루고있으며, Roll 조도의 급속한 저하로 슬립현상과 채터링현상 등이 발생한다. 본 연구에서는 Work Roll 마멸 및 조도 저하에 큰 영향을 미치는 (1) 압연 가공길이 및 (2) 실험 재료의 종류에 따른 영향과 (3) 압연하중에 의한 Roll 조도변화를 실제 압연가공을 통하여 분석하고, (4) 알미늄 산화 게재물의 영향과 전사율을 연구하고저 한다.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.38-41
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• 1994

막분리(membrane separation)법은 막 전후의 압력차, 농도차 등을 추진력(driving foroe)으로 하여 분리대상물질에 대한 막의 선택투과성 차이를 이용, 분리를 행하는 것이다. 이 분리법은 기존의 분리공정인 심냉법(cryogenic separation)과는 달리 상변환 공정이 필요없어 에너지가 적게 들고 또한 PSA(pressure swing adsorption)법에서와 같은 cycle 운전이 필요없어 연속적으로 분리가 가능하며 시스템도 간단하다. 최근 기체 막분리의 경우 수소 및 탄산가스의 회수정제, 공기중의 산소와 질소의 분리 등에 실용화되고 있다. 여기서는 공기중의 산소를 분리하여 30-40% 산소부화공기(oxygen enriched air)를 간편하게 제조할 수 있는 산소부화막장치와 연소장치에의 응용기술 및 연구결과에 대해 간략히 소개하고자 한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.285-288
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• 2004

온라인 필기체 한자는 동일인의 동일 문자조차도 회수, 획순 및 형태의 변화가 다양할 뿐만 아니라 인식 대상이 방대하여 인식이 매우 어렵다. 또한 한자는 기본 자소의 조합에 의한 글자가 아닌 각각의 글자가 독립적으로 이루어져 있어 연속된 획들 간의 관련도를 파악하기 어렵고 획수도 1획에서 28획까지 다양하게 분포를 한다. 따라서 본 연구에서는 대분류 단계로 시작획 비교를 하고 이어진 세분류 단계에서 문자의 특징으로 방향코드와 특이점을 추출해내고 획수를 고려하여 DP 정합을 하는 2단계 인식 시스템을 제안하였다. 이로써 최적의 속도로 입력한 문자를 찾아낼 수 있도록 하였다.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.482-488
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• 1997

Copper recovery from waste water of electronic industry has been conducted effectively in a fluidized bed reactor. Initial concentration of copper in the waste water, liquid flow rate in the reactor, reaction temperature and time and current density between the cathode and anode in the reactor have been selected as operating variables. The effects of operating variables on the recovery of copper have been studied. It has found that the copper resolved in the waste water can be recovered continuously by means of a fluidized bed reactor The recovery of copper decreased with an increase in the initial concentration of copper in the waste water, while it increased with increasing reaction time and current density, however, it exhibited its maximum value with the variations of liquid flow rate and reaction temperature. The optimum reaction condition to maintain the copper recovery around 85% is as follows ; $X_o=3wt%$, $U_L=0.5cm/s$, $T=25^{\circ}C$, $I=7A/dm^2$ and t=2hrs within this experimental condition.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.654-658
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• 2012

In this study, $CO_2$ capture efficiency in relation to the inlet moisture content of the regenerator was investigated using potassium-based sorbents in the continuous process composed of two bubbling fluidized-bed reactors, where solid outlet configuration in the regenerator was converted from underflow to overflow. XRD (X-ray Diffraction), SEM (Scanning Electron Microscope) and TGA were performed to find out the effect of water pre-treatment according to inlet moisture content in the regenerator. The $K_2CO_3{\cdot}1.5H_2O$ structure of solid sorbents has been increased as inlet moisture content of the regenerator increased. As a result, the $CO_2$ capture efficiency increased as the $K_2CO_3{\cdot}1.5H_2O$ structure of solid sorbents increased since the reactivity of the sorbents has been improved by that structure generated by the water pre-treatment. And $CO_2$ capture efficiency increased about 3~8% after sorbent outlet configuration of the regenerator was changed underflow to overflow.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1122-1127
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• 2017

Currently, the consumer trends are increasing towards "natural" in all food systems. Therefore, in the flavor industry, the production of flavor esters by "natural" methods are needed. On the other hand, "natural flavor" is expensive to produce because of the limited natural source. Recently, the flavor obtained from the enzyme or microbial could be represented as "natural flavor". Ethyl butyrate is used most frequently as a fruity aroma in drinks and the processed food industry. In this study, ethyl butyrate was synthesized enzymatically using the ester synthetase obtained from the waste of pineapple and banana peel. The ethyl butyrate production optimization was analyzed using a response surface methodology. The enzyme reaction variances were composed of the ethanol content, butyric acid content, and reaction time. As a result, in ester synthetase obtained from banana peel, the maximum predicted production amounts were 45.8199 mM at an ethanol content of 38.7050 mM, butyric acid content of 50.9019 mM, and reaction time of 4.3662 h. In ester synthetase obtained from pineapple peel, the maximum predicted production was 65.1087 mM at an ethanol content of 54.6502 mM, butyric acid content of 58.7638 mM, and reaction time of 4.7436 h. In conclusion, ethyl butyrate production was shown the more useful using the ester synthetase obtained from pineapple peel than that from banana peel.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3175-3184
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• 1997

To support large storage capacity and real-time characteristics of continuous media storage systems, we need to improve the performance of disk I/O subsystems. To improve the performance, we exploited buffer sharing scheme that reduces the number of disk I/Os. We utilized the advance knowledge of continuous media streams that is used to anticipate data demands, and so Promoting the sharing of blocks in buffers. In this paper, we proposed a buffer replacement algorithm that enables subsequent users requesting the same data to share buffer efficiently. The proposed algorithm manages buffers by utilizing reference interval information of blocks. In order to verify validity of the proposed algorithm, we accomplished simulation experiments and showed the results of performance improvements compared to traditional buffer replacement algorithms.

• Resources Recycling
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• v.31 no.6
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• pp.18-24
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• 2022

Dry reduction using natural gas was proposed to recover tin from waste tin oxide generated in a tin bath that was used for controlling the smoothness of architectural glass during production, and the reduction behavior was investigated. The utilized vertical natural gas dry reduction system is capable to process 4 L or 20 kg depending on input raw materials. The system was established by applying the upper intake and lower discharge method. The recovery rate was 97.2% at 800 ℃ and 4 sccm flow rate and increased with the amount of input gas. Hydrogen accounted for 23% of the discharge gas, showing a 16.6% hydrogen conversion rate. The reaction behavior of tin recovered via natural gas reduction provides basic data on the new waste resource reduction/recovery technology.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.763-770
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• 1997

The separation of benzene-cyclohexane mixture using (O/W)/O emulsion liquid membrane was studied. The operating parameters which can affect the selectivity, benzene yield, and emulsion size distribution were examined and determined by the batch type operation. The unsteady state and steady state extraction behavior in continuous pulse stirred reactor(CPSR) were verified. The optimum conditions for benzene selectivity and yield in batch operation were as follows; emulsion mixing intensity 4000 rpm, Tween 80 concentration 0.4%, volume ratio of membrane phase to internal phase 0.75, volume ratio of dispersed phase to continuous phase 0.5, and permeation time 10 minutes, As impeller speed increased and the microdrop holdup decreased, the Sauter mean diameter decreased. Turbulence damping parameter of modified Calabrease correlation considering microdrop holdup was 2.28. The optimum conditions of continuous operation were as follows; agitation speed 300 rpm, pulse frequence 2 times/sec, flow rate of continuous phase 30ml/min, and flow rate of emulsion phase 12.0ml/min.

• Resources Recycling
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• v.31 no.4
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• pp.34-39
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• 2022

In this study, effects of ultrasonic energy on the cementation reaction and copper recovery rate were investigated for different types of iron samples, such as plate, chip, and powder, for recovering copper from waste etchant, which contained ~3.5% copper. The cementation reaction using the ultrasonic energy was more effective than the simple stirring reaction, with the former exhibiting a high copper recovery rate than the latter for the same time interval. When cementation was performed for 25 min with ultrasonic treatment, rather than simple stirring, the copper recovery rate of the plate, chip, and powder improved from 7.0% to 12.0%, 14.0% to 46.1%, and 41.9% to 77.2%, respectively. Therefore, the use of ultrasonic energy could detach the copper recovered by the cementation reaction from the surface of the iron samples, thereby increasing the copper recovery rate. Owing to the use of ultrasonic energy, the copper recovery rate increased by 2-6 times, and the recovered copper exhibited a decreased particle size compared to that obtained via simple stirring.