• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.467-473
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• 2005

Liquid phase nitrous oxide ($N_2O$) contains air, carbon monoxide, water, carbon dioxide and NOx as main impurities. It is known to be very dangerous to obtain a very pure $N_2O$ product by using solidification at low temperature. In this study a new method to obtain a high purity of $N_2O$ product based on a continuous distillation process was introduced. For the modeling of the continuous distillation process to obtain a product having a purity over 99.999％ of $N_2O$ stream, Intalox wire gauze packing- No. SCH-80S gauze packing column was used. Peng-Robinson equation of state was used for the modeling of the continuous distillation process and refrigeration system. Computational results performed in this work showed a good agreement with Aspen Plus simulation results.

• Korean Journal of Biological Psychiatry
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• v.19 no.1
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• pp.45-52
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• 2012

Objectives : This study was designed to investigate the usability of IVA + Plus (Continuous Performance Test) and Neuro-Guide [Quantitative electroencephalography (EEG) normative database] as an auxiliary diagnostic tools for attention-deficit hyperactivity disorder (ADHD). Methods : The scores of IVA + Plus and resting EEG were obtained from 34 elementary school-aged children. Also, the Korean ADHD Rating Scale (K-ARS) and the Diagnostic Interview Schedule for Children version IV (DISC-IV) was done for the parent of them. From the result of the DISC-IV, we divided them into three groups, ADHD Not Otherwise Specified (NOS), and Normal Control (NC). Using NeuroGuide, the z-scores of relative power for delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), and beta (12-25 Hz) were calculated. Then the correlation and variance analysis were done to investigate the differences between three groups. Results : The scores of IVA + Plus were negatively correlated with the K-ARS. IVA + Plus have successfully discriminated the ADHD from NC and NOS. The z-scores of relative power of delta and theta were positively correlated with the K-ARS. The z-scores of relative power of alpha and beta were negatively correlated with the K-ARS. Conclusions : The IVA + Plus and NeuroGuide QEEG test are expected to be used as the valuable tools for diagnosing ADHD accurately.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.92-95
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• 1999

본 논문에서는 음성에 의해 구동되는 이동천화를 구현하기 위한 기초 실험으로서, 이동전화상에서 많이 사용되는 단어 데이터를 직접 채록하여 단어 인식 실험을 수행하여 인식기의 성능을 평가하였다. 인식 실험에 사용된 단어 데이터베이스는 서울 화자 360명(남성화자 180명, 여성화자 180명), 41상도 화자 240명(남성화자 120명, 여성화자 120명)으로 구성된 600명의 발성을 이용하여 구성하였다. 발성 단어는 이동전화에 주로 사용되는 중요 기능과 제어 단어, 그리고 숫자음을 포함한 55개 단어로 구성되었으며, 각 화자가 3회씩 발성하였다. 데이터의 채집환경은 잡음이 다소 있는 사무실환경이며, 샘플링율은 8kHz였다. 인식의 기본단위는 48개의 유사음소단위(Phoneme Like Unit : PLU)를 사용하였으며, 정적 특징으로 멜켑스트럼과 동적 특징으로 회귀계수를 특징 파라미터로 사용하였다. 인식실험에서는 OPDP(One Pass Dynamic Programming)알고리즘을 사용하였다. 인식실험을 위한 모델은 각 지역에 따라 학습을 수행한 모델과, 지역에 상관없이 학습한 모델을 만들었으며, 기존의 16Htz의 초기 모델에 8kHz로 채집된 데이터를 적응화시키는 방법을 이용하여 학습을 수행하였다. 인식실험에 있어서는 각 지역별 모델과 지역에 관계없이 학습한 모델에 대하여, 각 지역별로, 그리고 지역에 관계없이 평가용 데이터로 인식실험을 수행하였다 인식실험 결과, $90\%$이상의 비교적 높은 인식률을 얻어 인식시스템 성능의 유효성을 확인할 수 있었다.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.34-41
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• 1996

The heat of evaporation (cold energy) of LNG is the energy consumed in the production of LNG. This energy amounts to 14% of the NG. In Pyungtak LNG terminal, it is about 96 MW in 1993. In order to utilize the cold energy, the cold power generation systems are investigated: The Rankine cycle using the low temperature energy, the partial expansion cycle using the pressure energy, and the Linde process which is a combined cycle of the Rankine and the partial direct expansion cycle. The commercial simulator, ASPEN Plus, is used. The conceptual design data are obtained from the current facilities of the Pyungtak LNG terminal. The performances of three systems are evaluated. The amount of electric power ranges iron 3 MW to 6MW. The optimum energy efficiency is about 37%. The optimum design conditions are obtained for the partial direct expansion (PDE) cycle. The performance of the PDE cycle is supposed to be comparable to that of the Rankine cycle if the areas of the total heat exchanger of the both cycle are equal.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.128-134
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• 2012

The pilot scale experiments can handle the flue gas up to 1,000 $Nm^3/hr$ for separation of carbon dioxide included in real flue gas at coal-fired power plant. The operational characteristics was analyzed with the main experimental variables such as flue gas flow rate, absorbent circulation rate using chemical absorbents mono-ethanolamine( MEA) and 2-amino-2-methyl-1-propanol(AMP). The more flue gas flow rate decreased in 100 $m^3/hr$ in the MEA 20 wt% experiments, the more carbon dioxide removal efficiency was increased 6.7% on average. Carbon dioxide removal efficiency was increased approximately 2.8% according to raise of the 1,000 kg/hr absorbent circulation rate. It also was more than 90% at $110^{\circ}C$ of re-boiler temperature. Carbon dioxide removal efficiency of the MEA was higher than that of the AMP. In the MEA(20 wt%) experiment, carbon dioxide removal efficiency(85.5%) was 10% higher than result(75.5%) of ASPEN plus simulation.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.69-83
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• 2020

Light olefins are important petrochemicals as well as primary building blocks for various chemical intermediates. As the number of ethane cracking center (ECC) process, in which ethylene accounts for most of the production, has increased in recent years, propylene supply is not catching up with steadily increasing propylene demand. This trend makes the conversion of methanol to olefins to get more industrial importance. The methanol to olefins (MTO) process produces methanol through syngas and obtain olefins such as propylene through methanol. Since the reaction from methanol to olefins provides different product compositions depending on the catalyst used for the reaction, it is important to choose an appropriate separation process for the reaction product with different composition. Four different separation processes are considered for four representative cases of product compositions. The separation processes for the reaction products are evaluated by techno-economic analysis based on the simulation results using Aspen plus. Guidelines are provided for selecting a suitable separation process for each of representative case of product compositions in the MTO process.

• Clean Technology
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• v.17 no.4
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• pp.329-335
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• 2011

$SF_6$ gas is well known as a global warming gas. Global warming potential of $SF_6$ gas is 22,000 times higher than that of $CO_2$. Recycling of $SF_6$ gas is an essential technology for the sake of the environment and the economy. The recovery processes of $SF_6$ gas studied in this work were liquefaction, distillation, and crystallization processes because these processes were thought to be easily carried to the fields for recycling waste $SF_6$ gas. The processes were simulated and optimized using Aspen plus. The optimization problems were formulated to minimize energy consumption with satisfying product specification and desired recovery. The performance of the processes was compared based on the optimization results. Effects of major process variables on the recovery performance were investigated and optimal operation guide for changing product specification and product recovery was provided.

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.571-584
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• 1991

잉어과(Gyprinidae)의 Zocco속 어류 4종과 Candidia속 어류 1종에 대한 종간 유연관계와 종분화 연대측정 및 이들의 지질학적 분포경로를 밝히기 위하여 한국, 일본 및 대만에서 채집된 개체를 대상으로 전기영동법에 의한 유전자 분석을 하였다. 각 종의 지역별(한국, 일본, 대만) 집단간 유전적 유연관계를 분석한 결과 평균 유전적 근연치는 90% 이상이었다. Z. temmincki의 경우 일본집 단들은 한국의 A-type 집단과는 유연관계가 가까왔으나 한국의 B-type과는 유전적 차이가 현저하러다. Z. PlaD여5의 경우 한국집단과 일본집단사이의 유연관계는 S = 0.852였고, 한국집단과 대만집단 사이는 5 = 0.672, 일본집단과 대만집단 사이는 S = 0.751로서 지리적으로 현저한 차이를 업였다. Z. pochycephalus 3개 집단간의 유전적 근인치는 S = 0.963이었고 Candidia borbota 2개 집단간은 S = 0.946이었다. 종간의 유전적 근연환계를 비교한 결과 Candidia borbota와 Z. temmincki사이는 S = 0.608, Z. pluDpus와 1. pachycephalus사이는 S = 0.612였으나, Z. temmincki와 Z. platypus사이는 S = 0.441, Z. temmincki 와 Z. pochycepholus 사이는 S = 0.350이었고, Z. plotpus와 Condfda barbata사이는 S = 0.328로서 이들 사이에는 현저한 유전적 차이가 있었다. 각 종간의 롱분화 연대를 추산한 결과 이들은 약 480만년 전인 Pliocene 초기에 공통 조상종에서 분화하여 Z. temmincki, Candidia borbato group과 Z. plotypus, Z. pochycepholus group으로 분리되었고 약 260만년 전인 Pliocene 후기에 Z. temminc소와 Candidia borbota로 분화되었다고 추산되며 약 80만년 전인 Pleistocene시기에 남 temmincki B-type에서 h-type이 분화되었다짙 여겨진다. 한편 또 다른 한 단opP은 약 230만년 전인 열iocene후기에 대만 지역의 Z. plotypas에서 Z. pochvcepholus가 분화된 후 현재에 이르렀다고 추정된다. Z. platypus는 약150만년 이전인 초기 Pleistocene시기에 대만지역에서 한국 및 일본집단으로 분리되었다고 보며 이들 한국집단과 일본집단은 약 50만년 전 Pleistocene의 Middle기에 고황하 수계를 거쳐 현재의 분포 상황에 이르렀다고 여겨진다. 한편 대. temmin체과의 B-type에서 저온 적응으로 분화되었다고 추측되는 A-type은 약 20만년 전인 Pleistocene의 Riss기에 역시 고황하 수계를 통하여 한국과 일본으로 분포하여 현재에 이르렀다고 사료된다.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.69-77
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• 2015

The PMV regression analysis was conducted for this model based on a database of the PMV variables. PMV regression model simplification was completed through sensitivity and data analysis. The simplified PMV regression model's and Fanger PMV model was confirmed through MAE and RMSE. And the EMS in EnergyPlus was used to establish a simplified PMV regression analysis-based thermal comfort control. Also, the thermal comfort controls based on simplified PMV model and the Fanger PMV model were applied to the building model, it was confirmed that both controls met the thermal comfort range in more than 90% of cases during the air conditioning period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4643-4651
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• 2013

In this study, we have surveyed the new technologies in the cryogenic distillation of ITER, equilibrium reactors and helium refrigeration cycle contained in the isotope separation system (ISS). We also have collected thermodynamic and transport properties for $H_2$, HD, $D_2$, HT, DT and $T_2$ components of which properties are not built in a general purpose chemical process simulators such as Aspen Plus and PRO/II with PROVISION. Verification works have been performed to compare between literature data and simulation results. For the simulation of ISS involving six hydrogen isotope components, four distillation columns and two equilibrium reactors are used for the separation of $D_2$ and DT from $T_2$.