• Title/Summary/Keyword: Key Barrier

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Fabrication of Nb_{3}$Sn superconducting wire from large billet stage (Nb_{3}$Sn 초전도 선재용 대형 빌렛 제조 및 가공 조건 연구)

  • 하동우;오상수;하홍수;이남진;권영길;류강식
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2000.02a
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    • pp.9-11
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    • 2000
  • A key technology for achieving commercial Nb_{3}$Sn superconducting wires may be driven from fabrication process of big-scale billets. There was no breakage in the strand that was constituted with annealed sub-element. It was need that billet had to treat HIP because of remove of voids and good contact between Cu and Nb filaments. Ta wound sheet was better than Ta tube for barrier in the strand.

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Neonatal innate immunity and Toll-like receptor

  • Yoon, Hye-Sun
    • Clinical and Experimental Pediatrics
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    • v.53 no.12
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    • pp.985-988
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    • 2010
  • The innate immune response is the first line of defense against microbial infections. Innate immunity is made up of the surface barrier, cellular immunity and humoral immunity. In newborn, immunologic function and demands are different to adults. Neonatal innate immunity specifically suppresses Th1-type immune responses, and not Th2-type immune responses, which are enhanced. And the impaired response of macrophages is associated with the defective innate immunity in newborn period. Toll-like receptors (TLRs) play a key roles in the detection of invading pathogens and in the induction of innate immune responses. In newborn, the expression of TLRs is age dependent, so preterm has low expression of TLRs. Also, there are defects in signaling pathways downstream of TLRs. As a consequence, the defects of TLRs activity cause the susceptibility to infection in the neonatal period.

Sphingolipids and Antimicrobial Peptides: Function and Roles in Atopic Dermatitis

  • Park, Kyungho;Lee, Sinhee;Lee, Yong-Moon
    • Biomolecules & Therapeutics
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    • v.21 no.4
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    • pp.251-257
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    • 2013
  • Inflammatory skin diseases such as atopic dermatitis (AD) and rosacea were complicated by barrier abrogation and deficiency in innate immunity. The first defender of epidermal innate immune response is the antimicrobial peptides (AMPs) that exhibit a broad-spectrum antimicrobial activity against multiple pathogens, including Gram-positive and Gram-negative bacteria, viruses, and fungi. The deficiency of these AMPs in the skin of AD fails to protect our body against virulent pathogen infections. In contrast to AD where there is a suppression of AMPs, rosacea is characterized by overexpression of cathelicidin antimicrobial peptide (CAMP), the products of which result in chronic epidermal inflammation. In this regard, AMP generation that is controlled by a key ceramide metabolite S1P-dependent mechanism could be considered as alternate therapeutic approaches to treat these skin disorders, i.e., Increased S1P levels strongly stimulated the CAMP expression which elevated the antimicrobial activity against multiple pathogens resulting the improved AD patient skin.

Barix Multilayer Barriers; a key enabler for protecting OLED displays and flexible organic devices

  • Moro, L.L.M.;Rutherford, N.;Chu, X.;Visser, R.J.;Graf, G.C.;Gross, M.E.;Bennet, W.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.616-619
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    • 2005
  • OLED display are extremely sensitive to water and oxygen. Developing a thin film encapsulation for this technology has for a long time been elusive. Vitex has developed a multilayer barrier consisting of alternating inorganic and organic layers which can meet the requirements for a successful protection for such displays. In this paper we will discuss the basic process, the model, the results on top and bottom emission OLED displays as well as the application of Barix layers on plastic to create flexible OLED displays. We will show that for displays all the requirement for the telecommunication industry can be met and that the we can scale up to a mass manufacturing process.

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Multiscale Modeling of Radiation Damage: Radiation Hardening of Pressure Vessel Steel

  • Kwon Junhyun;Kwon Sang Chul;Hong Jun-Hwa
    • Nuclear Engineering and Technology
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    • v.36 no.3
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    • pp.229-236
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    • 2004
  • Radiation hardening is a multiscale phenomenon involving various processes over a wide range of time and length. We present a multiscale model for estimating the amount of radiation hardening in pressure vessel steel in the environment of a light water reactor. The model comprises two main parts: molecular dynamics (MD) simulation and a point defect cluster (PDC) model. The MD simulation was used to investigate the primary damage caused by displacement cascades. The PDC model mathematically formulates interactions between point defects and their clusters, which explains the evolution of microstructures. We then used a dislocation barrier model to calculate the hardening due to the PDCs. The key input for this multiscale model is a neutron spectrum at the inner surface of reactor pressure vessel steel of the Younggwang Nuclear Power Plant No.5. A combined calculation from the MD simulation and the PDC model provides a convenient tool for estimating the amount of radiation hardening.

Recent Research Activities for Continuous SiC Fiber Reinforced Ceramic Matrix Composites in Japan (일본에서의 탄화규소장섬유세라믹스강화 복합재료 연구개발)

  • Ogasawara, Toshio
    • Ceramist
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    • v.9 no.6
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    • pp.18-23
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    • 2006
  • In this article, the present activities regarding research and development of continuous SiC fiber reinforced ceramic matrix composites (CFCC) in Japan are reviewed. The key technologies in SiC fiber composites are interphase between fiber and matrix and its oxidation resistance. To improve oxidation resistance of interphase, various kinds of technologies such as environment barrier coating, high dense matrix, unti-oxidation matrix, multi-layered intephase have been developed. It is suggested that high performance, affordable processing cost, and excellent reliability will be important factors to be in practical use of CMCs in future.

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EPD time delay in etching of stack down WSix gate in DPS+ poly chamber

  • Ko, Yong Deuk;Chun, Hui-Gon
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2002.11a
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    • pp.130-136
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    • 2002
  • Device makers want to make higher density chips as devices shrink, especially WSix poly stack down is one of the key issues. However, EPD (End Point Detection) time delay was happened in DPS+ poly chamber which is a barrier to achieve device shrink because EPD time delay killed test pattern and next generation device. To investigate the EPD time delay, a test was done with patterned wafers. This experimental was carried out combined with OES(Optical Emission Spectroscopy) and SEM (Scanning Electron Microscopy). OES was used to find corrected wavelength in WSix stack down gate etching. SEM was used to confirm WSix gate profile and gate oxide damage. Through the experiment, a new wavelength (252nm) line of plasma is selected for DPS+ chamber to call correct EPD in WSix stack down gate etching for current device and next generation device.

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A Spatial-domain Fourier Transform Infrared Spectrometer: Application for Analyte Measurement in Cell Culture Media

  • Jung, Byung-Jo
    • Journal of the Optical Society of Korea
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    • v.9 no.4
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    • pp.151-156
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    • 2005
  • A spatial-domain Fourier Transform (FT) infrared (IR) spectrometer coupled with a PtSi Schottky­barrier IR detector plane was developed in the spectral range of $2.0-2.5{\mu}m$ for noninvasive measurement of analyte concentrations in cell culture media during cell culture processing. A key optical component of the spectrometer is a Savart plate which is a birefringent polarizer generating coherent two rays for interfering. The spectral resolution of the spectrometer was determined as $71cm^{-1}$ (${\~}0.05{\mu}m$ at $2.5{\mu}m$). Clear IR fringe patterns were imaged on the IR detector plane. The feasibility of the spectrometer for our application was investigated by measuring absorbance spectra of glucose and fetal bovine serum (FBS) which are important compounds in cell culture media. Experiment results show that the spectral quality of glucose and FBS was comparable with the standard spectra acquired with a commercial FT-IR spectrometer, presenting the feasibility of the spectrometer to perform analyte measurement in cell culture media.

Selection of Machining Inclination Angle of Tool Considering Tool Wear in High Speed Ball End Milling (고속 볼앤드밀링에서 공구마모를 고려한 공구의 가공경사각 선정)

  • Ko, Tae-Jo;Jung, Hoon;Kim, Hee-Sool
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.9
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    • pp.135-144
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    • 1998
  • High speed machining is a key issue in die and mold manufacturing recently. Even though this technology has great potential of high productivity. tool wear accelerated by high cutting speed to the hardened materials is other barrier. In this research, we attempted to reduce tool wear by considering tool inclination angle between tool and workpiece. The boundary lines describing machined sculptured surfaces were represented by both of cutting envelop condition and the geometric relationship of successive tool paths. Chip cross section, and cutting length could be obtained from the calculated cutting edge and the rotational engagement angle. From the simulation results, machining inclination angle of tool of $15^\circ$ was good enough from the point of tool wear and cutting force, and this value was verified through the cutting experiment of high speed ball end milling.

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The Electrical Characteristics of Recrystallized Silicon by CW $CO_2$ Laser (CW $CO_2$ 레이저에 의하여 재결정화된 실리콘의 전기적 특성)

  • Park, Jong Tae;Lee, Moon Key;Kim, Bong Ryul
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.1
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    • pp.79-84
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    • 1987
  • In this study, the recrystallization of polycrystalline silicn by CW CO2 laser is reported. With a variation of CW CO2 laser power, the surface morphology of recrystallized silicon is observed by SEM and the value of resistivity and mobility is obtained by Hall measurement. From the obtained results, it is concluded that the polycrystalline silicon is locally melted at 39W laser power and the reduction of resistivity and the increase of mobility are caused by the increase of grain size and the reduction of the potentical barrier at grain boundaries.

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