• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.11-11
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• 2004

나노기술은 크게 2가지 접근방법을 가진다. 하나는 위에서 아래로(Top-Down)라는 관점으로 벌크물질로부터 이온빔 등을 이용해 이를 작게 잘라가는 방식이며, 다른 하나는 아래에서 위로(Bottom-Up) 방식으로 재질을 구성하는 분자를 재구성해 원하는 물성 및 특성을 가지도록 만드는 방법이다. 이 두 가지 접근 방법은 원하는 결과를 얻기 위해 상호 보완적으로 사용되기도 한다. Top-Down방식의 대표적인 기기로는 접속이온빔 장치(FIB, Focused Ion Beam)를 등 수 있으며, Bottom-Up방식의 대표적인 기기로는 SPM(Scanning Probe Microscope)을 들 수 있다.(중략)

• Journal of the Korea Institute of Military Science and Technology
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• 제13권6호
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• pp.1121-1126
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• 2010

Borosilicate glass (81% $SiO_2$-2% $Al_2O_3$-13% $B_2O_3$-4% $Na_2O_3$) was prepared, and the glass was ion exchanged in $KNO_3$ powder containing different temperature and time. The $K^+-Na^+$ ion exchange takes place at the glass surface and creates compressed stress, which raise the mechanical strength of the glass. The depth profile of $Na^+$ and $K^+$ was observed by electron probe micro analyzer. With the increasing heat-treatment time from 0min to 20min, the depth profile was increased from 17.1um to 29.4um, but mechanical properties were decreased. It was also found out that excessive heat treatment brings stress relaxation. The Vickers hardness, Fracture Toughness and bending strength of ion exchanged samples at $570^{\circ}C$ for 10min were $821.8H_v$, $1.3404MPa{\cdot}m^{1/2}$, and 953MPa, which is about 120%, 180%, and 450% higher than parent borosilicate glass, respectively. Transmittance was analyzed by UV-VIS-NIR spectrophotometer. Transmittance of ion exchanged borosilicate glass was decreased slightly at visible-range. It can be expected that transparent bulletproof materials in more light-weight and thinner by ion exchanged borosilicate glass.

• Proceedings of the KIEE Conference
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1008-1010
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• 2005

In the examination of steam generator(SG) tube in nuclear power plant, eddy current testing probes play an important role in detecting the defects. Bobbin probe and MRPC probe is usually used for the inspection of SG tube. Bobbin probe is good at high speed inspection, but ability of detection of circumferential defect is very weak. On the contrary MRPC probe, which moves for inspection in the direction of axial and circumferential simultaneously, has very slow inspection speed, but it has excellent detection capability for small cracks, which is hardly detected by bobbin probe. In this paper, for the accurate analysis of experimental ECT signals, construction of MRPC probe signals database according to the variation of defect size is the main purpose. Using 3-D finite element method, ECT signals are analyzed, and signals analysis add according to frequency ingredient. The results, which are analysis and characteristics ion of electromagnetism simulation signals, is databased.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3717-3723
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• 2022

For the first time, two-dimensional temporal behavior of the edge localized mode (ELM) filament is measured in the edge tokamak plasma with a multi-channel electrical probe array (MCEP). MCEP, which has 16 floating probes (4 × 4), is mounted at the far scrape-off layer (SOL) region in the KSTAR. An electron temperature and an ion flux are measured by sideband method (SBM), which can achieve two-dimensional measurements with high time resolution. Furthermore, temporal evolutions of the electron temperature and the ion flux are obtained during the ELM occurrence. In the H-mode period, short spikes from ELM bursts are observed in measured plasma parameters, and the trend is similar to that of typical Hα signal. Interestingly, when blob-like ELM filaments crash the probe, the heat flux is significantly higher in a local region of the probe array. The results show that our probe array using the SBM can measure the ELM behavior and the plasma parameters without the effect of the stray current caused by the huge device. This study can provide valuable data needed to understand the interaction between the SOL plasma and the plasma facing components (PFCs).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.314-317
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• 2004

On 9/5/2003, the planet probe “HAYABUSA” as MUSES-C project was launched by The Institute of Space and Astronautical Science. “HAYABUSA” has microwave discharge ion engines and these engines are characterized by their high efficiency and specific impulse in comparison with chemical engine. A large ion engine can be used as a planet explorer, while a small ion engine can be used as attitude control of small satellite. We have been developing a high thrust density microwave discharge ion engine using “Multi-Monopole Antenna”. The performance of this engine are: ion cost of 344W/A, propellant utilization efficiency of 52% and thrust density of 0.055mN/$\textrm{cm}^2$ for Kr gas flow rate of 2.5sccm, microwave(2.45㎓) power of 32W and acceleration voltage of l.4㎸.

• The Transactions of the Korean Institute of Electrical Engineers
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• 제41권5호
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• pp.492-501
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• 1992

In this paper, an ion analyzer is used in conjunction with a Langmuir probe to study the chracteristics of ECR plasma such as the ion temperature, ion current density and electron temperature as the operating pressure, ${\mu}$-wave power and axial position change, Silicon etching has been performed with RF-biasing and its etching chracteristics have been discussed in terms of the ion energy distribution function. The maximum value of ion current density appears in the range of 10S0-3T mbar and the broadening of ion energy distribution function increases as pressure increases. Therefore, as pressure decreases, anisotropy increases but selectivity to photoresist decreases.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.91-94
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• 2008

Newly developed Atom Probe Tomography (APT) technique can provide the highest available spatial resolution, 3D tomography imaging and quantitative chemical analysis in a sub-nm scale. As a complementary technique to APT, Nano-secondary ion Mass Spectroscopy (SIMS) also provides the boron distribution in micro-scale. Therefore, the exact behavior of boron at either grain boundary or grain interior in steels can be investigated by the combination of APT and SIMS techniques from the sub-nanometer scale to the micrometer scale. The results obtained by both APT and SIMS revealed that the boron atoms were mainly segregated to the grain boundaries rather than to the grain interior in the steels containing 50ppm and 100ppm boron. It also found that carbon atoms were segregated at the boron enriched regions, which were thought to be retained austenite phase due to the chemical composition of carbon atoms.

• Transactions of Materials Processing
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• 제15권1호
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• pp.21-26
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• 2006

A optical head unit for nano optical probe array was developed. The optical probe array is generated by Talbot effect. The shape and thickness of microlens array(MLA) were designed to minimize the spot size at the foci of MLA. To increase the optical efficiency of the system and obtain the large tolerance for fabrication, aperture size was theoretically optimized. Then microlens illuminated aperture array(MLIAA) as an optical head unit was fabricated using a ultra violet(UV) molding process on aluminum aperture array. In this process, Al aperture array was fabricated separately using the photolithography and reactive ion etching(RIE) process. Optical properties of the generated optical probes were measured and compared at Talbot distance from the aperture array having a diameter of $1{\mu}m$ and MLIAA.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1061-1064
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• 2013

A known $Hg^{2+}$ selective rhodamine B derivatised probe 1 was reinvestigated as a colorimetric and fluorescent probe for $Cu^{2+}$ through changing the applied solvent media. Probe 1 exhibited good selectivity and sensitivity to $Cu^{2+}$ in $CH_3CN-H_2O$ (7:3, v/v, HEPES 10 mM, pH 7.0) solution with a detection limit of $9.74{\times}10^{-7}$ M. The $Cu^{2+}$ sensing event was proved to be irreversible through hydrolysis of 1 to release rhodamine B.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.29-34
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• 2005

A optical head unit for nano optical probe away was developed. The optical probe array is generated by Talbot effect. The shape and thickness of microlens array(MLA) were designed to minimize the spot size at the foci of MLA. To increase the optical efficiency of the system and obtain the large tolerance for fabrication, aperture size was theoretically optimized. Then microlens illuminated aperture array(MLIAA) as an optical head unit was fabricated using a ultra violet(UV) molding process on aluminum aperture array. In this process, Al aperture array was fabricated separately using the photolithography and reactive ion etching(RIE) process. Optical properties of the generated optical probes were measured and compared at Talbot distance from the aperture array having a diameter of $1{\mu}m$ and MLIAA.