• Radioisotope journal
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• v.20 no.3
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• pp.73-74
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• 2005

• Proceedings of the Korean Ceranic Society Conference
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• 2004.04b
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• pp.36.3-36.3
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• 2004

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.1
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• pp.10-17
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• 2000

Recently, as the field of cyclotron application is to be wider, to inject the beam whree the user want to is getting more important. But since it is not the easy way to describe the model equation of cyclotron, it could be operated by only operator's experiences. In this paper, we suggest the cyclotron controller using the fuzzy logic and the genetic algorithm. The proposed controller was verified in useful by applying to the cyclotron's beam line. In the experiment the measured results were obtained by VXIbus and the control algorithm was performed by LabWindows/CVI.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.4
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• pp.261-268
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• 1999

Laser-induced thermochemical etching has been recognized as a new powerful method for processing a variety of materials, including metals, semiconductors, ceramics, insulators and polymers. This study presents characteristics of direct etching for Si substrate using focused argon ion laser beam in aqueous KOH and $CCl_2F_2$ gas. In order to determine process conditions, we first theoretically investigated the temperature characteristics induced by a CW laser beam with a gaussian intensity distribution on a silicon surface. Major process parameters are laser beam power, beam scan speed and reaction material. We have achieved a very high etch rate up to $434.7\mum/sec$ and a high aspect ratio of about 6. Potential applications of this laser beam etching include prototyping of micro-structures of MEMS(micro electro mechanical systems), repair of devices, and isolation of opto-electric devices.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.91-94
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• 1999

A new type of high-T$_c$ superconducting Josephson junctions has been prepared by Ar ion beam etching and electron beam lithography. YBa$_2Cu_3O_{7-x}$ (YBCO) films deposited on (001) SrTiO$_3$ single crystal substrate by pulsed laser deposition were patterned by Ar ion milling with photolithography. The narrow slit with a electroresist mask, about 1000 ${\AA}$ wide, was constructed over a 3 ${\sim}$ 5 ${\mu}$m bridge of a 1200-${\AA}$-thick YBCO film by electron beam lithography. The slit was then etched by the Ar ion beam to form a damaged 600-${\AA}$-thick YBCO. Thus prepared structure forms an S-N-S (YBCO - damaged YBCO - YBCO) type Josephson junctions. Those junctions exhibit RSI-like I-V characteristics at 77 K. The properties of the Josephson junctions such as I$_c$ R$_N$, and J$_c$ were characterized.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.370-370
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• 2007

The liquid crystal (LC) aligning capabilities treated on the Organic overcoat thin film surfaces by ion beam irradiation and rubbing method was successfully studied for the first time. The Organic overcoat layer was coated by spin-coating. In order to characterize the LC alignment, the microscope, pretilt angle, thermal stress, and atomic force microscopy (AFM) image was used. The good LC aligning capabilities treated on the Organic overcoat thin film surfaces with ion beam exposure of $45^{\circ}$ above ion beam energy density of 1200 eV can be achieved. But, the alignment of defect of NLC on the Organicovercoat surface at low energy density of 600 eV was measured. The pretilt angle of NLC on the Organic overcoat thin film surface with ion beam exposure of $45^{\circ}$ for 1 min at energy density of 1800eV was measured about 1.13 degree. But, low pretilt angles of NLC on the Organic overcoat thin film surface with ion beam exposure at energy density of 600, 1200, 2400, and 3000 eV was measured. Also, the pretilt angle of NLC on the rubbed Organic overcoat thin film surfaces was measured about 0.04 degrees. Finally, the good thermal stability of LC alignment on the Organic overcoat thin film surface with ion beam exposure of $45^{\circ}$ for 1 min can be measured.

• Electrical & Electronic Materials
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• v.7 no.2
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• pp.100-106
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• 1994

A bilayer film consisting of a layer of a-Se$_{75}$ Ge$_{25}$ with a surface layer of silver -100[.angs.] thick and a monolayer film of a-Se$_{75}$ Ge$_{25}$ are irradiated with 9[keV] Ga$^{+}$ ion beam. The Ga$^{+}$ ion (10$^{16}$ [ions/cm$^{2}$] exposed a-Se$_{75}$ Ge$_{25}$ and Ag/a-Se$_{75}$ Ge$_{25}$ thin films show an increase in optical absorption, and the absorption edge on irradiation with shifts toward longer wavelength. The shift toward longer wavelength called a "darkening effect" is observed also in film exposure to optical radiation(4.5*10$^{20}$ [photons/cm$^{2}$]). The 0.3[eV] edge shift for ion irradiation films is about twice to that obtained on irradiation with photons. These large changes are primarily due to structural changes, which lead to high etch selectivity and high sensitivity.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.109-115
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• 2000

Effects of the heavy-ion ($^{14}$ N or $^{20}$ Ne) beam irradiation on the response of anthers, growth of calli, germination of seeds, and the early growth after the germination of tobacco (Nicotiana tabacum L. cv. BY-4) were investigated. Anthers precultured for 10 days before the irradiation became brown without callus or shoot induction over 20 Gy of $^{14}$ N and $^{20}$ Ne ion beam irradiation. Relative growth rate of the cultured calli was reduced by the irradiation and became brown significantly 2 weeks after the $^{14}$ N and $^{20}$ Ne ion beam irradiation over 50 Gy. The increased intensity of the heavy-ion ($^{14}$ N, $^{20}$ Ne) beam irradiation resulted in the delay of seed germination and the inhibition of the early growth both in water-treated and non-treated seeds before the irradiation. In addition, the heavy-ion beam irradiation to the imbibed seeds inhibited seed germination more than that to the non-imbibed seeds. The screening approach of non-imbibed seeds with heavy-ion beam irradiation using in vitro culture system was more useful than the filter-paper germination method in investigating the characteristics of heavy-ion beam-irradiated seed population and the screening of morphological variants at the early stage of the plant growth.

• 한국가시화정보학회:학술대회논문집
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• 2005.12a
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• pp.64-68
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• 2005

In this study, the smoke flows of the inner subway station were visualized through a numerical analysis and visualization experiment in the subway fire. A transparent acrylic model was designed and installed as 1:25th scale-down as the actual subway station by using geometrical similarity The properties of subway fire were reconstructed according to Densimetric Froude Similarity. The 47 to 53 ratio of the mixed air and Helium was inputted in the inner acrylic model to describe 1MW fire intensity with reference to the experiment paper. For the same time, the fire smoke from a smoke generator was inputted in the inner acrylic model with the mixture. At this time, the buoyancy effect of Helium gas went up the smoke to the acrylic model. When the sheet beam of Ar-lon laser was given out to the top and stair of subway model, the digital camcorder took the images of the scattered cluster of smoke particles when applying the smoke management system and PSD.

• KSBB Journal
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• v.17 no.3
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• pp.235-240
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• 2002

The surface of polypropylene was modified by 1 keV $Ar^+$ ion beam in an $O_2$ environment in order to enhance wettability. Contact angle of deionized water on modified polypropylene was reduced from $78^{\circ}$to $22^{\circ}$. The enhanced wettability is originated from newly formed functional groups such as ether, carbonyl, and carbonyl groups. During immersion in deionized water, the enhanced wettability has remained nearly same. After washing in water, the hydrophilic functional groups on the polymer surface have been very stable. The modified polypropylene was adopted as bio-film media to remove organics in synthetic wastewater. Microbe adhesion on the polypropylene surface was improved due to the newly formed hydrophilic groups.