• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.886-888
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• 1998

By irradiating photoresist on Si or glass with $Ar^+$ (${\lambda}$=514 nm, CW) and Nd:YAG (${\lambda}$=266 and 532nm, pulse) laser beam, the photoresist was etched masklessly in air. Using a fourth harmonic Nd:YAG laser beam, the etching threshold of energy fluence was $25\;J/cm^2$ and the damage of substrate was appeared over $40\;J/cm^2$.

• Korea Journal of Hospital Management
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• v.18 no.3
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• pp.62-82
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• 2013

Unlike administrative affairs of a general organization, hospital administration employees distinctively have a lot of interactions with patients and their care givers in addition to interaction with different occupations such as doctors and nurses. Although they are in a normal organization hierarchy as general employees, they have to be equipped with professional knowledge as medical terminology, disease and drugs and to understand new technologies and capabilities. This study analyzes the level of job satisfaction and the turnover intention of administrative employees who are engaged in medical institutes. It compares job satisfaction and the difference of turnover intention by the characteristics of job-related and scale of medical institutes. In addition, it verifies the relative in fluence of variables related to demographic and job-related characteristics as factors for explaining the job satisfaction of the administrative employees.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.108-112
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• 1993

The term Alkali-Silica Reaction (ASR) is used to describe a reaction between certain siliceous aggregates and hydroxyl ions present in the pore fluid of a concrete. The ASR is affected by the content of alkali, the particle size and the content of reactive aggregate, water-cement ratio, humidity, temperature and so on. In this paper, the fluence of alkali content and kind of added alkali to the ASR was studied. As a result, the more the content of alkali was increased, the more the mortar-bar was expand and the expansion of mortar-bar was showed differently with the added alkali kinds, The reaction products by ASR were observed by SEM(Scanning Electron Microscope) and analyzed by EDXA(Energy Dispersive X-ray Analysis) also and showed a gel composed of alkali(Na+, K+), silica and calcium.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.167-175
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• 2001

Semiconductor diode detectors coated with neutron reactive material are presently under investigation for various uses, such as remote sensing of thermal neutrons, fast neutron counting, and thermal neutron radiography. Theory indicates that single-coated devices can yield thermal neutron efficiencies from 4% to 11 %, which is supported by experimental evidence. Radiation endurance measurements indicate that the devices function well up to a limiting thermal neutron fluence of $10^{13}/cm^2$, beyond which noticeable degradation occurs. Thermal neutron contrast images of step wedges and simple phantoms, taken with dual in-line pixel devices, show promise for thermal neutron imaging detectors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.748-751
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• 2000

Microlens made by laser radiation method have advantages in the easiness of their fabrication. The process is based on the projection of a chromium-on-quartz reticle on to the Polymer using a pulsed 248nm KrF excimer laser. Fabrication process is a fluence-dependent rate and density. The lens shape is defined by a rotationally symmetric sluence distribution with smooth radial variation in the image plane of the reticle. A typical lens of 50㎛ diameter was fabricated by irradiating 2000 laser pulses within 40 seconds. The experimental results show microlens fabrication by UV laser is possible and well worth studying further.

• Laser Solutions
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• v.11 no.1
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• pp.25-31
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• 2008

The characteristics of femtosecond laser ablation of $Al_2O_3$ for prescision microfabrication are studied experimentally. Specifically, the process time during femtosecond laser drilling of microholes with $sub-100{\mu}m$ diameter are investigated for varying laser fluence, scan speed and beam path designs like trepanning with continuously changed start points. The accumulation of sub-micrometer size particles within the hole and the deterioration of edge clarity and roundness for decreasing hole diameter are examined and through process optimization the microdrilling with good hole quality is achieved using a femtosecond laser system (repetitionrate 1 kHz, wavelength 785 nm, pulse duration 185 fs)

• Laser Solutions
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• v.11 no.1
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• pp.19-24
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• 2008

It has been recognized that laser dicing of wafers results in low mechanical strength compared to the conventional sawing techniques. Thermal shock generated by rapid thermal loading is responsible for this problem. This work presents a two-dimensional ultra-short thermo elastic model for numerical simulation of femtosecond laser ablation of metals in the high-fluence regime where the phase explosion is dominant. Laser-induced thermoelastic stress is analyzed for Ni. The results show that the laser-induced thermal shock is large enough to induce mechanical damages.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.216-219
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• 1999

A simple two-terminal cyclic current-voltage(I-V) technique is used to measure the current-transients in MOS capacitors. Distinct charging/discharging currents were measured and analyzed as a function of (1) the hold time. (2) the gate polarity during the FNT electron injection, (3) the injection fluence and (4) the annealing time after the injection had stopped. Discharging and charging current-transients were strongly dependent upon the conditions for forming the inversion layer and the density of interface traps caused during the FNT electron injection, respectively. Several tentative mechanisms were suggested in the current work.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.620-624
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• 2004

Optical emission studies were performed to investigate thermal and dynamical properties of a plume produced by laser ablation of a graphite target in a nitrogen atmosphere. Experimental spectra of $C_2(d^3{\Pi}_g{\to}a^3{\Pi}_u$, ${\Delta}_V$=1) and CN ($B^2{\Sigma}^+{\to}X^2{\Sigma}^+,{\Delta}_V=0)$ were simulated to obtain the vibrational and rotational temperatures of the electronically excited species at various laser fluences and distances from the target. The spectroscopic temperatures of both molecules were found to be nearly independent of the laser fluence. The temperature of CN molecules was peaked in the middle of the plume while that of $C_2$decreased with increase in the distance. At a given distance, the temperature of CN molecules was clearly higher than that of $C_2$.

• Nuclear Engineering and Technology
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• v.33 no.5
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• pp.498-513
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• 2001

Performed here is a comparative assessment study for the generation of the pressure- temperature (P/T) limit curve of the reactor vessel. Using the cooling or heating rate and vessel material properties, the stress distribution is obtained to calculate stress intensity factors, which are compared with the material fracture toughness to determine the relations between operating pressure and temperature during cool-down and heat-up. P/T limit curves are generated with respect to crack direction, clad thickness, toughness curve, cooling or heating rate and neutron fluence, and their results are compared.