• Korean Journal of Materials Research
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• v.14 no.3
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• pp.186-190
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• 2004

An electron beam microcolumn composed of an electron emitter, micro lenses, scan deflector, and focus lenses have been fabricated and tested in the STEM mode. In this paper, we report a technique of precisely aligning the electron lenses by the laser diffraction patterns instead of the conventional alignment method based on aligner and STM. STEM images of a standard Cu-grid were observed using a fabricated microcolumn under both the retarding and accelerating modes.

• Applied Microscopy
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• v.45 no.3
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• pp.150-154
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• 2015

Negative staining electron microscopy facilitates the visualization of small bio-materials such as proteins; thus, many electron microscopists have used this conventional method to visualize the morphologies and structures of biological materials. To achieve sufficient contrast of the materials, a number of imaging parameters must be considered. Here, we examined the effects of one of the fundamental imaging parameters, electron beam exposure time, on electron densities generated using transmission electron microscopy. A single site of a negatively stained biological sample was illuminated with the electron beam for different times (1, 2, or 4 seconds) and sets of micrographs were collected. Computational image processing demonstrated that longer exposure times provide better electron densities at the molecular level. This report describes technical procedures for testing parameters that allow enhanced evaluations of the densities of electron microscopy images.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.68-69
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• 1998

Nano-crystalline silicon(nc-Si) thin films were directly depposited by ion beam assisted electron beam depposition (IBAED) method. The visibe luminescence in IBAED sampples were originated from not an oxygen bond but Si nano-crystallites. And we can conclude that the ion beam would be contribute to the suppression of the Si-O bond formation.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.942-948
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• 2003

This paper about the small electron beam irradiator for solar cell's efficiency. Many things are studied by method to increase conversion efficiency of solar cell. We selected electron beam by method for conversion efficiency of solar cell. Energy bands of this electron beam irradiator is 80keV(max.). And, solar cells that apply in this paper are crystal Si. Average efficiency of solar cell that applies in this experiment is 10$\%$. This system manufactured low energy electron beam irradiator. And, electron beam irradiation to solar cell in vacuum chamber of this irradiator. Irradiation area is 20*20 [mm2] by 40[keV].

• KSBB Journal
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• v.29 no.4
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• pp.297-302
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• 2014

The autoclaving assisted by an irradiation pretreatment method was developed without toxic chemicals to produce fermentable sugars for their conversion to bioethanol. In the first step, electron beam irradiation (EBI) of rice straw was performed at various doses. The electron beam-irradiated rice straw was then autoclaved with DI water at $120^{\circ}C$ for 1 h. A total sugar yield of 81% was obtained from 300 kGy electron beam-irradiated rice straw after 72 h of enzymatic hydrolysis by Cellulase 1.5L (70 FPU/mL) and Novozyme-188 (40 CbU/mL). Also, the removal of hemicellulose and lignin was 32.0% and 32.5%, respectively. This result indicates that the environmentally-friendly pretreatment method of rice straw by an electron beam irradiation could be applied for bioethanol production in plant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.401-404
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• 2004

The electron beam machining provides very high resolution up to nanometer scale, hence the E-beam writing technology is rapidly growing in MEMS and nano-engineering areas. In the optical column of the e-beam writer, there are several lenses condensing and focusing electron beams from electron gun with fringing magnetic fields. To achieve small spot size as 1-2 nm for higher power of electron beam, magnetic lenses should be designed considering their magnetic field distribution. In this paper, the magnetic field at two condenser lenses and object lens are calculated with finite element method and discussed its performances.

• Journal of the Korean institute of surface engineering
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• v.43 no.4
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• pp.170-175
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• 2010

The GaAs epitaxial layers were grown on Si(100) substrates by molecular beam epitaxy(MBE) using the two-step method. The Si(100) substrates were cleaned with different surface cleaning method of vacuum heating, As-beam, and Ga-beam at the substrate temperature of $800^{\circ}C$. Growth temperature and thickness of the GaAs epitaxial layer were $800^{\circ}C$ and 1 ${\mu}m$, respectively. The surface structure and epitaxial growth were observed by reflection high-energy electron diffraction(RHEED) and scanning electron microscope(SEM). Just surface structure of the Si(100) substrate cleaned by Ga-beam at $800^{\circ}C$ shows double domain ($2{\times}1$). RHEED patterns of the GaAs epitaxial layers grown on Si(100) substrates with cleaning method of vacuum heating, As-beam, and Ga-beam show spot-like, ($2{\times}4$) with spot, and clear ($2{\times}4$). From SEM, it is found that the GaAs epitaxial layers grown on Si(100) substrates with Ga-beam cleaning has a high quality.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1483_1484
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• 2009

The electron collision cross sections for gases have been determined by electron beam and electron swarm method. Especially, measurements by electron swarm method is carried out by using the double shutter drift tube given by T.O.F. and Double shutter method.

• Journal of Adhesion and Interface
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• v.11 no.4
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• pp.162-167
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• 2010

In the present work, the effect of electron beam irradiation on the chemical and thermal characteristics of cellulose-based jute fibers was explored by means of chemical analysis, electron spin resonance analysis, ATR-FTIR spectroscopy, thermogravimetric analysis and thermomechanical analysis. Jute fiber bundles were uniformly irradiated in the range of 2~100 kGy by a continuous method using a conveyor cartin an electron beam tunnel. Electron beam treatment, which is a physical approach to change the surfaces, more or less changed the chemical composition of jute fibers. It was also found that the radicals on the jute fibers can be increasingly formed with increasing electron beam intensity. However, the electron beam irradiation did not change significantly the chemical functional groups existing on the jute fiber surfaces. The electron beam irradiation influenced the thermal stability and thermal shrinkage/expansion behavior and the behavior depended on the electron beam intensity.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1727-1732
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• 2008

We present a facile, yet versatile carbon nanofabrication method using electron beam lithography and resist pyrolysis. Various resist nanopatterns were fabricated using a negative electron beam resist, SAL-601, and were then subjected to heat treatment in an inert atmosphere to obtain carbon nanopatterns. Suspended carbon nanostructures were fabricated by wet-etching of an underlying sacrificial oxide layer. Free-standing carbon nanostructures, which contain 122 nm-wide, 15 nm-thick, and 2 ${\mu}m$-long nanobridges, were fabricated by resist pyrolysis and nanomachining processes. Electron beam exposure dose effects on resist thickness and pattern widening were studied. The thickness of the carbon nanostructures was thinned down by etching with oxygen plasma. An electrical biosensor utilizing carbon nanostructures as a conducting channel was studied. Conductance modulations of the carbon device due to streptavidin-biotin binding and pH variations were observed.