• Journal of the Semiconductor & Display Technology
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• v.19 no.1
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• pp.17-22
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• 2020

Recently, the decrease in thin film thickness has been actively studied by changing several physical elements such as the increase in revolution velocity of lower substrate equipped with AC or DC motor. In this paper, we propose a novel spin coater control system that changes AC or DC motor and common use software with limitation of velocity and position control into step motor and LABVIEW software based on GUI to control revolution velocity and position more precisely. By determining six input values of rotation velocity 1, 5, 10, 25, 50, 100 PPS, we fabricated six samples using coating target, TA(tantalum) on silicon substrate and measured their thin film thickness by SEM. Hence, this research can be applied to inferring thin film thickness of tantalum regarding any value of revolution velocity without additional experiments and for linear reference model via property analysis of thin film thickness using other thin-film materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.500-504
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• 2023

In this study, the heteroepitaxial thin film growth of β-Ga₂O₃ was studied according to the position of the susceptor in mist-CVD. The position of the susceptor and substrate was moved step by step from the center of the hot zone to the inlet of mist in the range of 0~50 mm. It was confirmed that the average thickness increased to 292 nm (D1), 521 nm (D2), and 580 nm (D3) as the position of the susceptor moved away from the center of the hot zone region. The thickness of the lower region of the substrate is increased compared to the upper region. The surface roughness of the lower region of the substrate also increased because the nucleation density increased due to the increase in the lifetime of the mist droplets and the increased mist density. Therefore, thin film growth of β-Ga₂O₃ in mist-CVD is performed by appropriately adjusting the position of the susceptor (or substrate) in consideration of the mist velocity, evaporation amount, and temperature difference with the substrate, thereby determining the crystallinity of the thin film, the thickness distribution, and the thickness of the thin film. Therefore, these results can provide insights for optimizing the mist-CVD process and producing high-quality β-Ga₂O₃ thin films for various optical and electronic applications.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.973-979
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• 2001

Tin-doped indium oxide (ITO) thin films were deposited using r.f. magnetron reactive sputtering and the electrical properties, such as the resistivity, carrier concentration and mobility, were investigated as a function of the sample position under a given magnetron sputtering condition. The nonhomogeneity of the electrical properties with the sample position was observed under a given magnetron sputtering condition. The resistivity of ITO thin film on the substrate which corresponded to the center of the target had a minimum value, 2∼4$\times$10$\^$-4/$\Omega$$.$cm, and it increased symmetrically when the substrate deviated from the center. The density measurement result also showed that ITO thin film deposited at the center has a maximum density of 7.0g/cm$^3$, which was a relative density of about 97%, and the density decreased symmetrically as the substrate deviated from the center. The nonhomogeneity of electrical properties with the deposition position could be explained with the incidence angle of the source beam alpha, which is related with an atomic self-shadowing effect. It was confirmed experimentally that the density in film affect both the carrier mobility and the conductivity. In the case where the density of ITO thin film is 7.0g/cm$^3$, the magnitude of the mean free path was identical with that of the grain size(the diameter of column). However, in the other cases, the mean free path was smaller than the grain size. These results showed that the scattering of the free electrons at the grain boundary is the major factor for the electrical conduction in ITO thin films having a high density, and there exists other scattering sources such as vacancies, holes, or pores in ITO thin films having a low density.ing a low density.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.175-180
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• 2002

Use spctrophotometer to estimate thin film uniformity of lens, Compare, and analyze thin film uniformity availability selecting two peaks of Reflectance(R%) measuring on spectrum. Wavelength dependence's Reflectance in position of center, middle and edge of lens etc... obtain thin film's thickness (t) from Wavelength region (${\lambda}_1,{\lambda}_2$) of two peaks of Reflectance. $$t=\frac{1}{2(n^2-\sin^2{\theta})^{1/2}}{\times}\frac{{\lambda}_1{\lambda}_2}{{\lambda}_2-{\lambda}_1}$$ If Reflectance pattern is uniformity value in position of center middle of lens, edge etc... thin film has uniformity. Applied thin film uniformity estimation method to 1st layer $MgF_2$(n=1.38) coating lens. It was about thin film's thickness difference 360nm. Can analyze coating lens' thin film uniformity easily from Reflectance relationship measurement about Wavelength dependence.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.2
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• pp.122-127
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• 1994

Feeding preference of cigarette beetle, Lasioderma sewicorne F., on cured tobacco leaves was investigated to obtain basic information on ecological management of the insect pest in tobacco storage warehouses. About 3, 000-4, 000 adults of the insect were released in a warehouse in which groud tobacco leaves were placed on the bottom and at 3m above the floor level, and numbers of insects attracted were examined. There was no significant difference on feeding preference between the two tobacco varieties, flue-cured(NC82) and air-cured(Br3l) tobacco leaves. However, significant differences were noted in feeding preference between thick and thin leaves and among different quality grades within a tobacco variety. Feeding preferences of cigarette beetle between flue- and air- cured tobacco varieties showed significant differences on the lower position, though there were no differences on the 3m upper position. On the 3m upper position, feeding preferences were different between thick and thin leaves of tobacco varieties, and variety X thickness and variety X thickness equality grades showed statistically significant differences. Significantly higher feeding preference by cigarette beetle adults was observed for the food placed on the 3m upper than on the lower position. There were negative correlations between quality grades of cured tobacco leaves and feeding preference on the lower position, and the regression equation was Y(feeding preference)=4.050-0.683 X (degree).

• Journal of Welding and Joining
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• v.19 no.3
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• pp.317-324
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• 2001

This study deals with high power Nd:YAG laser welding of thin steels for small pressure vessels. Full penetration welding at the overlap joint was performed so as to assure sufficient weld strength. Results showed that mid-depth weld size reduced drastically with increasing the travel speed. Position of focus had little effect on the bead formation even though short focal system was used. However, the shape factor and the bead width had closely related with the position of focus. Based on the microstructural inspection, acceptable weld was obtained when the overlap clearance was controlled up to 20% of the base metal thickness. In the case that the joint contained more clearance than the critical value, both the tensile shear strength and the tear strength were reduced. Results also demonstrated that shielding gases were proved to play a key role as far as the bead formation characteristics was taken into consideration. Blowing dry air through 5mm in diameter nozzle produced narrower bead cross-section than that of argon or nitrogen shielding.

• Journal of Oral Medicine and Pain
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• v.41 no.3
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• pp.137-143
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• 2016

Posterior disk displacement (PDD) of the temporomandibular joint (TMJ) is a rare condition and most descriptions of TMJ PDD are about the adhesion of superior TMJ in which the position of disk is relatively posterior to anteriorly translated condyle in open mouth position. However, there have been reports about truly posteriorly positioned disk to the condyle in closed mouth position. This type of PDD has been classified into three subtypes-thin flat disk type, grossly posterior displaced disk type, and perforated disk type. Here, we report two rare cases of TMJ PDD, one with thin flat disk and one with perforated disk. Its possible etiology, pathogenetic mechanisms, related signs and symptoms, differential diagnoses, and treatments were reviewed and discussed.

• Bulletin of the Korean Mathematical Society
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• v.60 no.6
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• pp.1621-1639
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• 2023

In this paper, we give an improvement for the second main theorems of algebraically non-degenerate meromorphic maps from generalized p-parabolic manifolds into projective varieties intersecting hypersurfaces in subgeneral position with some index, which extends the results of Han [6] and Chen-Thin [3].

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1053-1057
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• 1997

Laser thin film process with a Q-switch pulsed YAG laser was performed for micro machining. In this research, we performed basic Cr thin film on glass substrates removal machining experiments. Form experiments, it happens not only evaporration of thin film but also spatter and cohesion of melting substance in working region, when machining a Cr thin film by Q-switch YAG laser beam irradiation. Critical energy of surface irradiation type by irradiation direction of laser in a face composing thin film on the glass is higher than that of back irradiation type, but the latter is favorable because of spatter appearance. In case of image formation position when laser beam is irradiated, the defocus is permitted to a certain extent within forcus depth. Ifexceeds focus depth, formation of pattern is vanishing step by step.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1720-1723
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• 2000

Boron doped conducting diamond thin film were grown on Si substrate by microwave plasma chemical vapor deposition from a gaseous feed of hydrogen, acetone/methanol and solid boron. The doping level of boron was controlled from 0ppm to $10^4$ppm (B/C). The Si substrate was tilted ca. 10$^{\circ}$ to make Si substrate have different height and temperature. Experimental results show that same condition but different temperature of Si substrate by height made different crystalline of diamond thin film. There were appeared 3$\sim$4 step of different crystalline morphology of diamond. To characterize the boron-doped diamond thin film, Raman spectroscopy was used for identification of crystallinity. To survey surface morphology, microscope was used. Grain size was changed gradually by different temperature due to different height. The Raman spectrum of film exhibited a sharp peak at 1334$cm^{-1}$, which is characteristic of crystalline diamond. The lower position of diamond film position, the more non-diamond component peak appeared near 1550$cm^{-1}$.