• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.267-271
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• 2009

The aim of this study is to evaluate wavelength dependence for laser-assisted lipolysis using a mathematical simulation. In this study, a Monte Carlo simulation was performed to simulate light transport in fat and dermal tissue with 3 different laser wavelengths (${\lambda}\;=\;1064\;nm$, 1320 nm, and 1444 nm) that are currently used in clinic settings for laser-assisted lipolysis. The relative rates of heat generation versus penetration depth showed that the greatest amount of heat generation was seen in the tissues at ${\lambda}\;=\;1444\;nm$. This Monte Carlo simulation may help lend insight into the thermal events occurring inside the fat and dermal tissue during laser-assisted lipolysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.167-174
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• 1997

The penetration depth and the size distribution of the droplets of fuel sprays are important in the operation of spark-ignition MPI engines. A fluorescence/scattering image technique for droplet sizing was applied to measure th edroplet size distribution in non-evaporating gasoline sprays. The fluorescence and scattering lights were imaged simultaneously by the two-dimensional visualization system composed of a laser sheet, a doubling prism, optical filters, and a CCD camera. Quantitative droplet size distributions were extracted from evaluating the ratio of the two light densities. The mean droplet size measured by the fluorescence/scattering technique was compared with the result obtained by the enlarged photographs of droplets. The fluorescence/scattering image technique also gives the useful information of the characteristics of droplet impingement in a inclined wall.

• Laser Solutions
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• v.8 no.3
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• pp.11-19
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• 2005

In automotive industry, light weight vehicle is one of issues because of the air pollution and the protection of environment. Therefore, automotive manufacturers have tried to adopt light materials such as aluminum alloy to production line. Aluminum welding using laser has some advantages high energy density and high productivity. It is very important to understand weld characteristic according to welding condition in order to determine the possibility of application to car body. In this study, Nd:YAG laser welding of 5182 aluminum alloy with filler wire AA5356 was carried out through experimental design according to wire feed rate, laser power and welding speed. Weld bead shape in terms of cross section photo, bead with, height of reinforcement and penetration depth and mechanical property in terms of tensile strength and formability was investigated. Analysis of variation (ANOVA) was performed to know the effect of weld parameter for weldability, laser power was statistically most significance factor of three variables.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.39-50
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• 2004

One of the challenge for successful daylighting design might be to capture sunlighting that varies in both intensity and position and to deliver the luminous flux into the inner space as deep as possible. Conventional glazing apertures allow daylight in the outer 3.5m of a perimeter spaces. More advanced daylighting technologies can extend this daylighting depth by reflecting sunlight further from the windows within a deep floor area. For this purpose, this study developed light shelves based on performance evaluation with a mock-up model that constructed recently and measured under real sky condition. All these daylighting devices have a customized geometry developed from the solar path at a given latitude and utilize unique reflecting finishing to maximize the amount of redirection and diffusion of the daylight. This paper tells that the best daylighting penetration typically can be expected from using light-colored sloped external shelves.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.61-67
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• 1982

Optical properties of sea water were studied in the southern sea of Korea, based on ten oceanographic stations in July, 1980. Submarine daylight intensity was measured at intervals of 5m depth in the upper 70m layer by using the underwater irradiameter (Kahlsico # 268 WA 360). The mean absorption coefficients of the sea water were shown as 0.102 (0.066~0.137), 0.119 (0.069~0.154), 0.091 (0.054~.0123), and 0.095 (0.056~0.129) for clear, red, green, and blue color respectively. The transparency ranged from 13 to 25 meters (mean 17.1 m). The mean water color in this area was 3.9 (3-5) in Forel scales. The relation between absorption coefficient (k) and transparency (D) was k=1.17/D, k=2.01/D, k=1.52/D, and k=1.60/D for clear, red, green, and blue color respectively. The rates of light penetration for clear, red, green, and blue color in four different depths were computed with reference to the surface light intensity respectively. The mean rates of light penetration in proportion to depths were as follows; clear : 57.3%(5m), 20.82%(15m), 5.16%(30m), 0.94%(50m). red : 52.2%(5m), 15.99%(15m), 2.99%(30m), 0.39%(50m). green : 60.9%(5m), 24.51%(15m), 7.11%(30m), 1.56%(50m). blue : 59.4%(5m), 22.92%(15m), 6.09%(30m), 1.29%(50m).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.95-101
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• 1980

Optical properties were studied at the fishing ground of anchovy in the southern part of Korea based on seven oceanographic stations from May to August and November to December, 1977. Submarine daylight intensity was measured at intervals of 1m depth in the upper 30 m layer by the underwater luxmeter (Toshiba # 9). The absorption coefficient of the sea water ranged from 0.066 to 0.619 (mean 0.21) for six months. The transparency ranged from 2.6 to 16 meters (mean 8.4m). The relationship between absorption coefficient (n) and transparency (D) was k=1.70/D. The mean water color in this area was 4.8 $(3\~10)$ in Forel scales. The rates of light penetration for daylight at four different depths were computed with reference to the surface light intensity. The mean rates of light penetration were $69.38\%(25.43\~88.10\%),\;30.35\%\;(4.38\~59.46\%),\;12.53\%\;(0.75\~33.51\%),\;5.7\%(0.18\~20.27\%)$ at depths of 1, 5, 10 and 15 m respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.17 no.2
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• pp.53-58
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• 1981

Optical properties of sea water were studied in the northwestern water of Jeju Island, based on seven oceanographic stations in July, 1980. Submarine daylight intensity was measured at intervals of 5m depth in the upper 70m layer by using the underwater irradiameter(Kahlsico #268 WA360). The mean absorption coefficients of the sea water were appeared as 0.106(0.084-0.152), 0.135(0.106-0.184), 0.089(0.069-0.130) for clear, red, green, and blue color respectively. The transparency ranged from 11 to 19 meters(mean 16.1m). The mean water color in this area was 4.3(3-5) in Forel scales. The relation between absorption coefficient(k) and transparency(D) was k=1.66/D, k=2.12/D, k=1.38/D, and k=1.51/D for clear, red green, and blue color respectively. The rates of light penetration for clear, red, green, and blue color in four different depths were computed with reference to the surface light intensity respectively. The mean rates of light penetration in proportion to depths were as follows; clear : 56.57%(5m), 20.54%(15m), 4.60%(30m), 0.68%(50m). red : 50.14%(5m), 2.37%(30m), 0.23%(50m). green : 62.29%(5m), 26.43%(15m), 7.74%(30m), 1.56%(50m). blue : 59.29%(5m), 23.43%(15m), 6.10%(30m), 1.08%(50m).

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.401-404
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• 2010

The ion-beam induced changes in the characteristics of gadolinium doped ceria (GDC) pellets have been studied by UV-visible spectroscopy (UV-vis), SEM, and XRD. Implanted ions were protons or Xe ions with the energy of 120 keV or 5 MeV. Densely sintered pristine GDC pellets have cubic fluorite structure and are brown in color. As the ion irradiation proceeded, its color gradually turned into light black and finally into dark black. XRD patterns of GDC pellets were closely related with ion energy and the penetration depth of X-ray. It showed that upon the ion irradiation (120 keV) the lattice parameter of the cubic fluorite phase just beneath the surface is increased.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.242-250
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• 1996

Glasses of Na2O-Al2O3-SiO2 system were prepared and ion-exchange characteristics change of properties and bactericidal effects by Na+↔Ag+ ion exchange were studied. Parent glasses with three compositions of varying Na2O in the 20~30 wt% were ion-exchanged in the molten salt of 2 mol% AgNO3+98 mol% NaNO3 at 320~36$0^{\circ}C$ for 15~16min. Amount of ion exchange and penetration depth of Ag+ ion increased with Na2O content in the parent glass ion exchange temperature and time. After ion exchange densities and Vickers hardness of the glasses increased and the glasses showed yellow-brown color and as amount of ion exchange increased the color turned deep because partial reduction and agglomeration of Ag+ into Ag0 results in absorption of visible light. After ion exchange chemical durability of the glass to wter was enhanced compara-bly that weight loss and change of surface of the glass were not found for the leaching test in 5$0^{\circ}C$ K.I water for 240hrs. Bactericidal effect of ion exchanged glass on Staphylococcus aureus and E. coli was determined by microorganism test and bactericidal effect increased with amount of ion exchange and incubation time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.92-95
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• 2005

The silver photodoping effect in amorphous AsGeSeS chalcogenide thin films for holographic recording has been investigated using a HeNe laser ($\lambda$=632.8 nm). The chalcogenide films prepared in this work were thinner in comparison with the penetration depth of recording light ($d_p$=1.66 mm). The variation of the diffraction efficiency $(\eta)$ in amorphous chalcogende films exhibits a tendency, independently of the Ag photodoping. That is, n increases relatively rapidly at the beginning of the recording process, reaches the maximum $({\eta}_{max})$ and slowly decreases. In addition, the value of ${\eta}_{max}$ depends strongly on chalcogenide film thickness(d) and its peak among the films with d = 40, 80, 150, 300, and 633 nm is observed at d = 150 nm (approximately 1/2n), where n is refractive index of the chalcogenide (n=2.0). The ${\eta}$ is largely enhanced by Ag photodoping into the chalcogenides. In particular, the value of hmax in a bilayer of 10-nm-thick Ag/150-nm-thick AsGeSeS film is about 1.6%, which corresponds to ~20 times in comparison with that of the AsGeSeS film (without Ag).