• Title/Summary/Keyword: Unit cell

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Unit Cell Analysis of Satin Weave Composites Using Macroelements (수자직 복합재료 단위구조의 마크로요소해석)

  • 우경식
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.10a
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    • pp.35-41
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    • 1997
  • Unit cell analyses were peformed to study the engineering properties of satin weave textile composites. Two 5-harness satin weave layers with fiber tow shifts were modeled by unit cells and repeating boundary conditions were applied at the outer surface of the unit cells. Multi-field macroelements were employed to consider the microstructure details and to effectively reduce computer memory requirements. Preliminary results indicated that the engineering properties of 5-harness satin weave textile composites can vary significantly according to the manner how the adjacent fiber tows were arranged in stacking.

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Visualization of Hepatitis B Virus (HBV) Surface Protein Binding to HepG2 Cells

  • Lee, Dong-Gun;Park, Jung-Hyun;Choi, Eun-A;Han, Mi-Young;Kim, Kil-Lyong;Hahm, Kyung-Soo
    • BMB Reports
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    • v.29 no.2
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    • pp.175-179
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    • 1996
  • Viral surface proteins are known to play an essential role in attachment of the virus particle to the host cell membrane. In case of the hepatitis B virus (HBV) several reports have described potential receptors on the target cell side, but no definite receptor protein has been isolated yet. As for the viral side, it has been suggested that the preS region of the envelope protein, especially the preS1 region, is involved in binding of HBV to the host cell. In this study, preS1 region was recombinantly expressed in the form of a maltose binding protein (MBP) fusion protein and used to identify and visualize the expression of putative HBV receptor(s) on the host cell. Using laser scanned confocal microscopy and by FACS analysis, MBP-preS1 proteins were shown to bind to the human hepatoma cell line HepG2 in a receptor-ligand specific manner. The binding kinetic of MBP-preS1 to its cellular receptor was shown to be temperature and time dependent. In cells permeabilized with Triton X-100 and treated with the fusion protein, a specific staining of the nuclear membrane could be observed. To determine the precise location of the receptor binding site within the preS1 region, several short overlapping peptides from this region were synthesized and used in a competition assay. In this way the receptor binding epitope in preS1 was revealed to be amino acid residues 27 to 51, which is in agreement with previous reports. These results confirm the significance of the preS1 region in virus attachment in general, and suggest an internalization pathway mediated by direct attachment of the viral particle to the target cell membrane.

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Distribution of Basal Cell Carcinoma and Squamous Cell Carcinoma by Facial Esthetic Unit

  • Choi, Jung Hun;Kim, Young Joon;Kim, Hoon;Nam, Sang Hyun;Choi, Young Woong
    • Archives of Plastic Surgery
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    • v.40 no.4
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    • pp.387-391
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    • 2013
  • Background The most common cutaneous malignant masses are basal cell carcinoma (BCC) and squamous cell carcinoma. The predominant site of a malignant mass is the face, which has many opportunities to be exposed to ultraviolet radiation. However the predilection sites of malignant masses have been equivocal due to the use of general regions, rather than anatomical landmarks, in surveys. A facial esthetic unit is an anatomical site classified as an area of similar facial contour characteristics that can be distinguished from other areas. The purpose of this study is to determine widely accepted anatomical landmarks using the esthetic unit. Methods We retrospectively analyzed 118 cases of malignant masses in our clinic from January 2005 to October 2012. We evaluated the patients' age, gender, and predilection site of the malignant mass by esthetic unit through pathology, medical records and patient photographs. We mapped the occurrence site of the malignant mass on schematic drawings of the esthetic units. Results Most of the malignant masses were BCC. The ratio of males to females was 1:1.41. The frequent predilection site of a malignant mass was on the nasal unit (33.1%), followed by the buccal unit (11.0%). Primary closure was the most common method of repairing a surgical defect (38.9%), followed by a local flap (35.5%). Conclusions This review described the relationship between clinical characteristics and esthetic units by proposing objective predilection sites for malignant masses, which can be used commonly as a framework in the study of malignant masses by unifying equivocal occurrence sites.

COMPUTATIONAL STUDY FOR PERFORMANCE EVALUATION OF FLOW CHANNELS INSIDE CDI UNIT CELL (수치모사를 이용한 CDI Unit Cell 내부의 유로성능 평가)

  • Sohn, D.Y.;Choi, Y.H.;Park, D.W.;Jung, C.H.
    • Journal of computational fluids engineering
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    • v.15 no.1
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    • pp.31-36
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    • 2010
  • In the present study, computations for flow fields inside the CDI unit cells with electrodes and spacers have been made to evaluate their performance. Three types of unit cells that include a planar type, a serpentine channel type, and a spiral wound type were considered and their flow characteristics were compared. From the computational results, it is found that the serpentine channel type has a large flow resistance and can not guarantee the outflow flux for industrial applications. On the other hand, the planar type can sustain a large enough outflow flux but it's efficiency is low for the electrode-use because of the non-uniform velocity distribution inside the cell and dead zones in every corner. Finally, The spiral wound type has not only a large outflow flux as much as the planar type has, but also a high efficiency for the electrode-use because of uniform velocity distribution. From this comparison, we can expect that the spiral wound type of CDI unit cell would have a high performance deionization capability.

Design and Fabrication of Wideband High Pass Filter Using Left-Handed Transmission Line (LH 전송선을 이용한 광대역 고역통과 필터 설계 및 제작)

  • Yang, Doo-Yeong;Seo, Soo-Duk;Cho, Hak-Rae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.2
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    • pp.260-267
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    • 2014
  • In this paper, the unit cell of LH structure using microstrip transmission line and chip capacitor is devised, and the reactive components of equivalent circuit are extracted from the proposed unit cell. And then, we have analyzed for the unit cell parameters and applied the characteristics to the wideband high pass filter design. This filter cascading several unit cells with high pass property has been implemented on microstrip transmission line, and the performance has been the band rejection characteristics of 62.9 dB in the stop band to 0~2.18 GHz and less than the insertion loss of 1.17 dB in the pass band from 3.0G Hz to 12.75 GHz.

A New Design of Blood Cell Counter using DSP chip and Optimal Discrimination Method (DSP 칩과 최적분별법을 이용한 새로운 혈구입자 계수기 설계)

  • Kim, G.H.;Kim, J.W.;Kim, K.S.;Hong, W.H.;Kim, S.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1991 no.05
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    • pp.89-93
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    • 1991
  • The purpose of this reserch is to design the blood cell counting instrument which can measure the number of RBC(Red Blood Cell) and WBC(White Blood Cell) including many other blood component. The proposed method uses the electrical impedence method and the new discrimination method wi th DSP chip and software algorithm. The system consist of control unit, blood cell discrimination unit, hemoglobin spectrometer, post detect ion processor unit, and IBM-PC interface unit. In this paper, the discrimination system has been implemented using digital signal processor, which result in the reduction of system hardware and cost. The system is helpful in providing necessary clinical test for screen test and quality control of hematology.

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Electrochemical studies of nano-scale solid electrolyte powder prepared by chemical synthesis process (화학적합성법에 의한 나노 고체 전해질 분말 합성 및 전기화학적 평가)

  • Kim, Young-Mi;Shin, Yu-Cheol;Kim, Ho-Sung
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.295-298
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    • 2009
  • Oxygen ionic conductors of CeScSZ electrolyte in SOFC unit cell are applied to anode and cathode as well as electrolyte to have the triple-phase-boundaries of electrochemical reaction, and it is required to decrease the sintering temperature of anode-supported electrolyte by the nanoscale of CeScSZ electrolyte powder. In this report, nanoscale CeScSZ electrolyte powder was synthesized by chemical synthesis method. The particle size, surface area and morphology of the powder were observed by SEM and BET. Thin film electrolyte of under $10{\mu}m$ was fabricated by tape casting using the synthesized CeScSZ electrolyte powder, and ionic conductivity and gas permeability of electrolyte film were evaluated. Finally the SOFC unit cell was fabricated using the anode-supported electrolyte prepared by a tape casting method and co-sintering, in which the active layer, measuring $20{\mu}m$, was introduced in the anode layer to provide a more efficient reaction. Electrochemical evaluations of the SOFC unit cell, including measurements such as power density and impedance, were performed and analyzed.

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Design of the Wideband Microwave Absorber for X-band Applications (X-대역 응용을 위한 광대역 전파 흡수체 설계)

  • Hong, Young-Taek;Jeoung, Gu-Ho;Choi, Jaehoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.9
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    • pp.749-755
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    • 2017
  • In this paper, a wideband microwave absorber for X-band(8~12 GHz) applications is proposed. The structure of the proposed absorber unit cell consists of a resonator with a slot and slit, a backing ground plate, and a Taconic RF-30(${\varepsilon}_r=3$, $tan{\delta}=0.0014$) substrate with a dimension of $8.5{\times}8.5{\times}0.5mm^3$. The proposed absorber has a dual resonance at 9.83 and 10.37 GHz. To demonstrate the operating principle of the proposed absorber structure at each resonance frequency, the simulated current distributions on the unit cell are analyzed. To verify the performance of the proposed absorber, a prototype absorber was fabricated with a planar array of $20{\times}20$ unit cells. The measured results exhibit two absorptivity peaks stronger than 99 % and full-width at half-maximum(FWHM) bandwidth of 1.1 GHz(9.51~10.61 GHz).

Prediction of Effective Material Properties for Triaxially Braided Textile Composite

  • Geleta, Tsinuel N.;Woo, Kyeongsik;Lee, Bongho
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.2
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    • pp.222-235
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    • 2017
  • In this study, finite element modeling was used to predict the material properties of tri-axially braided textile composite. The model was made based on an experimental test specimen which was also used to compare the final results. The full interlacing of tows was geometrically modelled, from which repeating parts that make up the whole braid called unit cells were identified based on the geometric and mechanical property periodicity. In order to simulate the repeating nature of the unit cell, periodic boundary conditions were applied. For validation of the method, a reference model was analyzed for which a very good agreement was obtained. Material property calculation was done by simulating uniaxial and pure shear tests on the unit cell. The comparison of these results with that of experimental test results showed an excellent agreement. Finally, parametric study on the effect of number of plies, stacking type (symmetric/anti-symmetric) and stacking phase shift was conducted.