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Multi-stage Process Study of PEI-PDMS Hollow Fiber Composite Membrane Modules for $H_2/CO_2$ Mixed Gas Separation ($H_2/CO_2$ 혼합기체의 분리를 위한 PEI-PDMS 중공사 복합막 모듈의 다단 공정 연구)

  • Lee, Chung Seop;Cho, Eun Hye;Ha, Seong Yong;Chung, Jong Tae;Rhim, Ji Won
    • Membrane Journal
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    • v.23 no.1
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    • pp.1-11
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    • 2013
  • Poly(ether imide) (PEI)-poly(dimethylsioxane) (PDMS) composite membranes and their modules were prepared, which are capable of selective $CO_2$ separation from the mixture gas. The gas flow rate, concentration, recovery ratio of $H_2$ and removal ratio of $CO_2$ outflowing by stage-cut were characterized at $25^{\circ}C$ and the constant pressure. In addition, to increase the recovery ratio of $H_2$, one stage, two stage series connection, and three stages series + parallel connection tests were carried out. When the stage-cut was 0.32 for the three stages connection operation, the concentration $H_2$ of the produced gas and the recovery ratio of $H_2$ was 97% and 85%, respectively. And also the removal ratio of $CO_2$ was 90% was obtained and the recycled gas concentration was similar with that of the feed gases.

A Fuzzy Resoning for Servo System by $\alpha$-Level Set Decomposition and Hardware Implementation ($\alpha$-레벨집합 분해에 의한 서보시스템용 퍼지추론과 하드웨어)

  • 안영주
    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.38-40
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    • 2000
  • In this paper we propose a calculation method for fuzzy control based on quantized $\alpha$-cut decomposition of fuzzy sets. This method is easy to be implemented in analog hardware. The effect of quantization levels on defuzzified fuzzy inference results is investigated. A few quantization levels are sufficient for fuzzy control. The hardware implementation of this calculation method and the defuzzification by gravity center method by PWM are also presented.

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Cutting Force Estimation Using Spindle Motor Power (주축 모터 동력을 이용한 절삭력 예측)

  • 최영준;김기대;주종남
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.1088-1094
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    • 1997
  • An indirect cutting torque and cutting force estimation method is presented. This method uses a time-domain model between the spindle motor power, which calculated form measured spindle motor current and voltage. Spindle motor power is linear with cutting torque in this model. The cutting force is proportional to the cutting torque. Using trial cut, parameters are determined. Static sensitivity is suitable for various cutting conditions. The presented method is verified under several cutting tests on the CNC horizontal machining center.

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Characteristics of Feed Mechanism in NC Lathe (수치제어선반의 이송특성에 관한 연구)

  • 여인완;박철우;이상조
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.7
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    • pp.104-118
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    • 1998
  • In this paper, the motion of ballscrew and shape of workpiece are the main objective variables varying with load conditions. To verify feed mechanism in NC lathe, the monitoring system is designed and cutting condition variables are spindle speed depth of cut and feed. During machining, rotation number of ballscrew motion of ballscrew in direction to gravity center and cutting force are measured. After machining, the roughness of workpiece is measured.

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Japanese Hornwort Mosaic Virus in Ornamental Flower and Its Phylogenetic Analysis with Other Potyvirusess.

  • Kim, Ok-Sun;Ueda, S;Ebihara, Y.;Uematsu, S.;Hanada, K.;Ohshima, K.;Iwanami, T.;Takanami, Y.;Choi, Jang-Kyung
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.142-143
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    • 2003
  • Ammi majus (white lace flower, Unbelliferae) is an ornamental plant used for cut-flower arrangements worldwide. A potyvirus was isolated from its leaves with mosaic and chlorotic symptoms in the cultivated field of Chiba, Japan. Compared with Japanese homuort mosaic virus (JHMV) previously isolated from Cryptotaenia japonica, it showed similar characteristics in host reactions and molecular properties. The nucleotide sequences of coat protein and 3'- nontranslated region were highly homologous and shared 87% and 91% identities with those of JHMV, respectively. This virus was thus supposed to be an isolate of JHMV and designated as JHMV-Am. Phylogenetic tree was constructed using CP nucleotide sequences of the two isolates and other potyviruses previously reported. JHMV-Am and JHMV fell into a cluster with Korean strain of Zantedeschia mosaic virus (ZaMV-KR). However, low identity in amino acid sequences was found in the termini of CP genes between the two isolates of JHMV and ZaMV-KR.

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A Study on the Space Element of Public Library Buildings as a Information Center (정보센터로서의 공공도서관 공간요소에 관한 연구)

  • 이상호;황창석
    • Korean Institute of Interior Design Journal
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    • no.17
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    • pp.87-93
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    • 1998
  • As the varification of public library services has been come true through the increase of multimedia information accompanied with the development of information tachnology and the advent of various electronic materials the repetitive and labo intensive process has been cut down by the development of network system. Recentrly the electronic library using outside networks electronic library facilities at the time of their new contructions. In this study it is aimed that the outline of the library planning is presented with the case analyses of domestic and foreign libraries especially concerning the kinds and features of the required spaces for electronic libraries their scale basic facilities. The conclusions of this study are : First the spaces requred for electronic library are as mentioned below: catalgue are equipped with terminal information service center reference room electronic reading room computer training center and conference room. Second computer room for management and electronic information center has been made recently in the Library of Seoul City. The space for librarians room is to be 5.48$m^2$ per person on average and for electronic information center of library provided with an exclusive use is to be 5.1$m^2$ per person.

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Analyses of structural dynamic characteristics and end milling in a vertical machining center (금형 가공기의 엔드밀 가공 및 구조 동특성 해석)

  • 이신영;김성걸;이장무
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.3
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    • pp.66-74
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    • 1997
  • In a high speed and high precision vertical machining center, chatter vibration is easily generated due to unbalanced masses in rotating parts and changtes of cutting forces. In this paper, modal test is performed to obtain modal parameters of the vertical machining center. In order to predit the cutting force of endmilling process for various cutting conditions, a mathematical model is given and this model is based on chip load, cutting geometry, and relationship between cutting forces and the chip load. Specific cutting constants of the model are obtained by averaging forces of cutting tests. The interactions between the dy- namic characteristics and cutting dynamics of the vertical machining center make the primary and the secondary feedback loops, and we make use of the equations of system to predict the chatter vibration. The chatter prediction is formulated as linear differential-differene equations, and simulated for several cases. Trends of vibration as radial and axial depths of cut are changed are shown and compared.

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Identification of Genes Differentially Expressed in Wild Type and Purkinje Cell Degeneration Mice

  • Xiao, Rui;Park, Youngsook;Dirisala, Vijaya R.;Zhang, Ya-Ping;Um, Sang June;Lee, Hoon Taek;Park, Chankyu
    • Molecules and Cells
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    • v.20 no.2
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    • pp.219-227
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    • 2005
  • Purkinje cell degeneration (pcd) mice are characterized by death of virtually all cerebellar Purkinje cells by postnatal day 30. In this study, we used DNA microarray analysis to investigate differences in gene expression between the brains of wild type and pcd mice on postnatal day 20, before the appearance of clear-cut phenotypic abnormalities. We identified 300 differentially expressed genes, most of which were involved in metabolic and physiological processes. Among the differentially expressed genes were several calcium binding proteins including calbindin-28k, paravalbumin, matrix gamma-carboxyglutamate protein and synaptotagamins 1 and 13, suggesting the involvement of abnormal $Ca^{2+}$ signaling in the pcd phenotype.

Fabrication of metal line on plastic substrate by hot embossing and CMP process (핫 엠보싱 공정과 CMP 공정을 이용한 플라스틱 기판에 메탈 라인 형성)

  • Cha, Nam-Goo;Kang, Young-Jae;Park, Chang-Hwa;Rim, Hyung-Woo;Park, Jin-Goo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.655-656
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    • 2005
  • In the future, plastic based system will play a crucial role in modem life, for examples, transparent display or disposable electronics and so on. In this paper, we introduced a new method to fabricate the metal line on the plastic substrate. Metal lines were fabricated by hot embossing and CMP process on PMMA (polymethylmethacrylate) substrates. A Si mold was made by wet etching process and a PMMA wafer was cut off from I mm thick PMMA sheet. A 100 nm thick Al was deposited on PMMA wafers. The Al deposited PMMA wafer and the Si mold carefully sandwiched which was directly imprinted by hot embossing. After imprinting process, a residual Al layer was removed by CMP process. Finally, we found the entire process may be very useful to fabricate the metal line on plastic substrates.

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Recent advances in development of commercial rose by molecular breeding (분자육종에 의한 장미 신품종 최근 개발 동향)

  • Oh, Myung-Jin;Kim, Jong-Hyun;Ahn, Myung-Suk;Liu, Jang-R.;Kim, Suk-Weon
    • Journal of Plant Biotechnology
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    • v.37 no.4
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    • pp.414-424
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    • 2010
  • This report describes recent advances in tissue culture, genetic transformation of commercial rose (Rosa hybrida) and in development of new rose cultivars by molecular breeding. Rose is one of major cut-flowers in global horticulture industry. Successful progresses were made in development of new cultivars for pathogen resistant, environmental stress resistant and petal color modification by molecular breeding. New cultivars, however, has not reported yet in korea, although lots of progresses were achieved in each field of conventional breeding, tissue culture and genetic transformation. Cooperation in these research fields will promote screening of useful genes to have specific traits on rose and exploiting of processes to improve in the efficiency of tissue culture and genetic transformation of rose, therefore, we hopefully expect that new rose cultivars by molecular breeding will be released in the near future.