• Journal of Korean Society of Steel Construction
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• v.12 no.2 s.45
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• pp.197-207
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• 2000

A transient heat transfer analysis and thermo-elastic analysis have been performed for the residual stress distribution on the fillet weldment used by finite element method. Specimen is fabricated single-pass fillet welding. This computation was performed for conditions including surface heat flux and temperature dependent thermo-physical properties using by heat input as parameter. Also, cut-off temperature of residual stress estimation by thermo-elastic analysis is determined. The fillet weldment were measured to determined their residual stress distributions for using hole-drilling method. As result, it was found that large tensile residual stress is about material yield strength, and the numerical simulation results for finite element method similar to residual stresses by hole-drilling method and other exiting research. Also, cut-off temperature is effectively determined by temperature which calculated maximum thermal stress equal to material yield strength.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.338-346
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• 2000

Although the net-shape molding of composites is generally recommended, molded composites are frequently required cutting or grinding due to the dimensional inaccuracy for precision machine elements . During the composite machining operations such as cutting and grinding, the temperature at the cutting point may increase beyond the allowed limit due to the low thermal conductivity of composites, which might degrade the matrix of composite. Therefore, in this work, the temperature at the cutting point during cut-off grinding of carbon fiber epoxy composites was measured. The cutting force and surface roughness were also measured to investigate the cut-off grinding characteristics of the composites. The experiments were performed both under dry and wet grinding conditions with respect to cutting speed and feed rate. From the experimental investigation, the optimal conditions for the composite cut-off grinding were suggested.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.480-486
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• 2006

Generally, IR cut-off filters for mobile phone is coated on the glass substrate at high temperature(above $300^{\circ}C$). In this work, we prepared IR cut-off filters on the poly(methyl methacrylate)(PMMA) substrates at low temperature(about $70^{\circ}C$ ). using the $CeO_2\;and\;SiO_2$ coatings by physical vapor deposition. The surface energies of coated and uncoated PMMA, and adhesive properties of IR cut-off filters coatings were examined using contact angle measurements. We demonstrate the improve of mobile phone optical system using these results.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.465-465
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• 2010

Cut off probe, the efficient method, can measure the plasma parameters like the plasma electron density and the electron temperature. Plasma potential is also one of the important parameters in plasma processing but cannot be measured by cut off probe yet. Thus we developed method to measure plasma potential by focusing on relation between bias on a tip and sheath around tip. The system consist of a ICP(Inductive Coupled Plasma) source, a Network analyzer and a bias tee that can be bridge apply DC voltage on the cut off probe tip. Plasma potential is identified by using this system. The results corresponded well with the measured results by single langmuir probe(SLP).

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.181-181
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• 2012

The microwave probe for measuring plasma density is widely used for its advantages: First, it is not affected by the reactive gas. Second, it can measure local plasma parameters such as plasma density, plasma potential and plasma temperature. Third, it is simple and robust. A cut-off probe is the one of the most promising microwave probe. Recently, Kim et al. reveals the physics of the cut-off probe but the effect of the sheath on the determination of the plasma density is not explained. In this presentation, for taking account of sheath effects on determination of plasma density from the cut-off peak, a simplified circuit modeling and an E/M simulation are conducted. The results show that occupation ratio of sheath volume between two tips of the cut-off probe and subsequence pressure condition mainly change position of the cut-off peak with respect to plasma frequency. Magnitude of relative voltage taken on the impedance of sheath and the impedance of bulk plasma can explain this effect. Furthermore, effects of gap size, tip radius, and tip length ware revealed based on above analysis.

• Ocean and Polar Research
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• v.27 no.3
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• pp.277-288
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• 2005

Spatial distribution and vertical structures of water masses around the Antarctic continental margin are described using synthesized hydrographic data. Antarctic Surface Water (AASW) over the shelf regime is distinguished from underlying other water masses by the cut-off salinity, varying from approximately 34.35 to 34.45 around Antarctica. Shelf water, characterized by salinity greater than the cut-off salinity and potential temperature less than $-17^{\circ}C$, is observed on the Ross Sea, off George V Land, off Wilkes Land, the Amery Basin, and the Weddell Sea, but in some shelves AASW occupies the entire shelf. Lower Circumpolar Deep Water is present everywhere around the Antarctic oceanic regime and in some places it mixes with Shelf Water, producing Antarctic Slope Front Water (ASFW). ASFW, characterized by potential temperature less than about $0^{\circ}C$ and greater than $-17^{\circ}C$, and salinity greater than the cut-off salinity, is found everywhere around Antarctica except in the Bellingshausen-Amundsen sector. The presence of different water masses over the Antarctic shelves and shelf edges produces mainly three types of water mass stratifications: no significant meridional property gradient in the Bellingshausen and Amundsen Seas, single property gradient where ASFW presents, and a V-shaped front where Shelf Water exists.

• Korean Journal of Optics and Photonics
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• v.3 no.1
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• pp.55-62
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• 1992

The optical absorption characteristics of glasses colored by CdS. CdSe, $CdS_{1-x}Se_x$,ZnS, and ZnSe microcrystallites have been studied with emphasis on changes of the cut-off wavelength. The sharpcut filters with various cut-off wavelengths were fabricated by controlling the composition and the heat-treatment temperature. The cut-off wavelength shifts due to the different heat-treatment temperatures for CdS. CdSe, ZnS, and ZnSe doped SK-16 glasses were found to be relatively small(~30 nm). However, by treating the CdS1,Se, doped SK-16 glasses with different x values at the same heattreatment temperature, it was possible to obtain the filters with various cut-off wavelengths(~130 nm) without losing the high extinction coefficients of the filters. The filter glasses with various cut-off wavelngths(~100 nm) and high extinction coefficiencts were also produced by treating the CdSe and $CdS_{0.5}Se_{0.5}$ doped ZK-1 glasses at different temperatures.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.3
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• pp.152-155
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• 2013

In this paper, the reduction of the figure of merit depending on the increased spill-over when the parabolic reflector is cut off partially for low-profile configuration in the satellite broadcast receiving antenna is analyzed. Also for the accurate analysis and simulation, it is considered that the noise temperature is increased due to the effect of ground thermal noise toword the sidelobes and back lobes when the antenna is tracked from $0^{\circ}$ to $60^{\circ}$ in elevation angle, and that the total noise temperature is increased because to the noise figure of LNA. As the results, noise temperature is increased up to about 15K and G/T ratio is decreased to about 2.5dB, when the reflector is cut 35% off partially.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.3
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• pp.95-102
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• 2012

Purpose: The purpose of this study is to define the cut off values of cold hypersensitivity of hands by using digital infrared thermographic imaging(DITI). Methods: Thermographic images of 130 patients with cold hypersensitivity of hands(CHHG, n=65) and non-cold hypersensitivity of hands(NCHHG, n=65) were retrospectively reviewed. We used the temperature difference the palm(PC8) and the upper arm(LU4) for diagnosing cold hypersensitivity of hands. The temperature differences of between two groups were analysed using independent samples t-tests. The cut off values were calculated by ROC curve analysis. Analyses were undertaken using SPSS version 17.0. P value of < 0.05 was considered significant. Results: The temperature difference the palm(PC8) and the upper arm(LU4) were significantly different between groups(p < 0.001). Using receiver operating characteristic curve analysis, the sensitivity, specificity, and area under the curve were 70.8%, 73.8%, respectively both hands. The AUC was 0.822 on right hand and 0.818 on left hand. The optimum cut-off value was defined as $-0.05^{\circ}C$. Conclusions: These results suggest that DITI is a reliable instrument for estimating the cold hypersensitivity of hands.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.3
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• pp.85-92
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• 2013

Objectives: The purpose of this study is to find diagnostic points and define the cut off values of hot flashes by using digital infrared thermographic imaging. Methods: Thermographic images of 75 patients with hot flashes (HF, n=35) and non-hot flashes (NHF, n=40) were retrospectively reviewed. We used the temperature difference between Ex-HN3 and CV17, LU4, CV12, CV4 for diagnosing hot flashes. The temperature differences of between two groups were analysed using independent samples t-tests. The cut off values were calculated by received operating characteristic curve analysis. Analyses were undertaken using SPSS version 17.0. and p-value of <0.05 was considered significant. Results: The temperature difference Ex-HN3 and LU4 were the most significantly different between groups (p<0.001). Using receiver operating characteristic curve analysis, the sensitivity, specificity, and area under the curve were 65.7%, 72.5%, 0.729, respectively. The optimum cut off value was defined as $1.00^{\circ}C$. Conclusions: These results suggest that the digital infrared thermographic imaging is a reliable instrument for estimating hot flashes.