• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.996-999
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• 2010

고압의 가스를 이용하여 고온 가스와 저온 가스를 분리하거나 입자상 물질의 분리에 사용할 수 있는 장치인 볼텍스 튜브의 에너지 분리 특성을 파악하기 위하여 $100Nm^3$/hr급 볼텍스 튜브를 제작하고 이에 대한 실험을 진행하였다. 저온측의 유량비와 오리피스 직경 및 볼텍스 튜브의 길이가 온도에 미치는 영향을 분석하였다. 오리피스 직경 0.6D에서 최적의 온도 분리 효과를 나타내었으며, 0.8D의 경우 그 효과가 미미하였다. 또 한 오리피스 직경이나 길이에 관계없이 저온유량비가 약 0.9부근에서 고온측의 온도가 최고점을 나타내었고, 볼텍스 튜브 길이는 저온측 온도 변화에 미미한 영향을 미치나, 오리피스 직경의 변화는 최저 온도점이 나타나는 저온 유량비에 상당한 영향을 미쳤다. 본 연구의 결과는 $100Nm^3$/hr급 볼텍스 튜브의 최적화를 위한 기초자료로 활용될 수 있을 것이다.

• Proceedings of the Membrane Society of Korea Conference
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• 1991.10a
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• pp.45-46
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• 1991

분리막 공정은 상변화를 일으키지 않기 때문에 장치비가 저렴하며, 열 및 화학적으로 민감한 물질, 특히 생체물질 등을 다루는데 적합하다. 또한 최종 생성물질을 정제하는 방법으로는 이온교환 크로마토그래피, 전기 영동 및 친화성 크로마토그래피(affinity chromatography)가 있다. 이중 친화성 크로마토그래피는 가장 선택적이고, 단일 장치로서 기존의 분리방법에 비해 약 1000배 가까이 정제할 수 있다. 본 실험에서는 트립신 억제제인 m-aminobenzamidine을 포함하고 있는 수용성 고분자를 제조하여 트립신을 선택적으로 분리하고자 하였으며, 본 연구 필요한 분리막은 막제조가 용이하며 비용이 저렴한 cellulose acetate막을 사용하였다. CA 막의 세공크기는 겔화매질의 에탄올 농도로 조절하였다. Casting 용액의 조성은 다음 표에 간략하게 나타내었다.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.311-320
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• 2014

A magnetic separation study was conducted for a soil sampled from a landfill site where steel slag had been dumped for a long time. Heavy metal concentrating effect was evaluated by analyzing heavy metal content of magnetically separated soil and passed through soil. The effect was compared between soil after soil-washing process and original landfill soil and the effect was also tested between wet condition-magnetic separation and dry condition-magnetic separation. Separated ratio was relatively higher in non-soil washed sample. The water content has no significant effect on the separation rate. The concentrating effect of Fe, Pb, Cu, and Cd were 3.2, 2.1, 12.1, 2.5, 1.5 and 17.4, 7.0, 15.7, 9.6, 7.0 respectively for non-soil washed sample and soil washed sample. We can expect a bigger volume reduction effect from soil-washed samples. The volume reduction effect was obtained from the separation in dry condition. However, when the separation ratio is too high the volume reduction effect decreases. The magnetic separation leads to a volume reduction and concentration of heavy metals into a portion of soil in case of paramagnetic particles contained soil.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.202-203
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• 2017

비음수 행렬 인수분해(Non-negative Matrix Factorization, NMF)의 신호분리 성능을 개선하기 위해 희소조건을 인가한 방법이 희소 비음수 행렬 인수분해 알고리즘(Sparse NMF, SNMF)이다. 기존의 SNMF 알고리즘은 개별 음원의 희소성을 고려하지 않고 임의로 결정한 희소 조건을 사용한다. 본 논문에서는 음원의 특성에 따른 희소성을 추정하고 이를 SNMF 학습알고리즘에 적용하는 새로운 신호분리 기법을 제안한다. 혼합 신호에서의 잡음제거 실험을 통해, 제안한 방법이 기존의 NMF와 SNMF에 비해 성능이 더 우수함을 보였다.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.121-128
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• 1998

In fields of operating or handling a hydrogen isotope facility, and of the technology for nuclear fusion source management, gas chromatography has been used as one of the practical techniques lot separation and enrichment of hydrogen isotopic gases including tritium. Chromatographic separation experiments of the hydrogen isotope mixture (hydrogen, deuterium and tritium) were carried out by use of a commercially available gas chromatograph. An aliquot of gas sample was injected by a specially designed vacuum sampler into the stream of inert carrier gas which went through the separation column under liquid nitrogen temperature. The complete separation of hydrogen isotopic molecules was observed with an alumina adsorbent partially deactivated by coating with 10% manganese chlorine. In addition, fairly good separation conditions were obtained without any appearance of nuclear spin isomers with shorter retention time, which would be available for the practical applications of the hydrogen isotope separation and enrichment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.10
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• pp.827-832
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• 2013

Heating wire cutting type separation mechanism has been widely used for cube satellite applications due to its design constraints such as small size of $10cm{\times}10cm{\times}10cm$ and light weight of less than 1kg. In addition, usage of pyro technic device is not allowed for cube satellite application. The conventional methods have some disadvantages of relatively small mechanical constraint force and the system complexity for the multi-deployable systems. In this paper, a separation nut type non-explosive separation mechanism has been proposed and investigated. The effectiveness of the design has been verified through the qualification tests of the mechanism.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.275-282
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• 2002

High fluidity concrete needs high dosage of superplasticizer to acquire sufficient fluidity and high contents of fine powder and viscosity agents to prevent segregation. But it requires high manufacturing cost and has difficult in quality control. Therefore, in this paper, determination of optimal mixture proportion of segregation type superplasticizer for high fluidity concrete and manufacturing high fluidity concrete by applying developed segregation reducing type superplasticizer are discussed using flowing concrete method. According to test results, as dosage of superplasticizer increases, it shows that fluidity and bleeding increase, while air contents and ratio of segregation resistance decrease. It also shows that adding viscosity agent into it reduce bleeding and improve segregation resistance. Dosage of AE agent into it containing viscosity agent recovers loss of air contents during flowing procedure. Combination of proper contents of superplasticizer, viscosity agent and AE agent make possible to develope segregation reducing type superplasticizer Compressive strength of high fluidity concrete applying flowing method with it is higher than that of base concrete. No differences of compressive strength between compacting methods are found.

• Computational Structural Engineering
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• v.7 no.1
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• pp.83-90
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• 1994

This study presents the nonlinear dynamic analysis method of the bridge with the seismic isolation bearing. Also the numerical analyses are performed for investigating the response characteristics of the bridge isolated with the lead-rubber bearing under the ground motions compatible to Korea bridge design response spectra. It is found that the pier design force can be considerably smaller than the one for the bridge with the fixed bearing. It is observed that the lead-rubber bearing has the great effectiveness for reducing the longitudinal seismic force in case of the bridges with low and medium periods. Therefore the seismic isolation bearing can be used instead of the fixed bearing for the economic and safe design of the bridge.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.243-248
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• 2005

Membrane pervaporation processes could have advantages over distillation for separation of water/organics mixtures: a low energy demand and the ability to separate azeotropic mixtures or isomers. Zeolite membranes might show better thermal, mechanical and chemical stabilities than polymer membranes. Water could be effectively separated from water/organic mixtures using the NaA zeolite membrane because of its high hydrophilicity. In this study, water was separated by pervaporation using the NaA zeolite membrane from water/ethanol mixtures. As a mole fraction of ethanol increased, the total permeation flux and the water flux decreased while the separation factor increased, reached a maximum point, and decreased. As an experimental temperature increased, the total permeation flux increased while the separation factor increased at the lower mole fraction of ethanol than 0.8 and it decreased at the higher mole fraction of ethanol than 0.8. The total permeation flux and the separation factor could be maintained constant during the long term experiment longer than 160 hours. It was found that the NaA zeolite membrane synthesized in our study showed better performance on water/ethanol separation than that of a distillation process or PVA polymeric pervaporation membranes.

• The Journal of the Acoustical Society of Korea
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• v.32 no.1
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• pp.79-85
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• 2013

Feature extraction of CASA system uses time continuity and channel similarity and makes correlogram of auditory elements for the use. In case of using feature extraction with cross correlation coefficient for channel similarity, it has much computational complexity in order to display correlation quantitatively. Therefore, this paper suggests feature extraction method using non-parametric correlation coefficient in order to reduce computational complexity when extracting the feature and tests to segregate target speech by CASA system. As a result of measuring SNR (Signal to Noise Ratio) for the performance evaluation of target speech segregation, the proposed method shows a slight improvement of 0.14 dB on average over the conventional method.