• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.995-1000
• /
• 2000

In this paper. a mechanistic model is first constructed to predict three-dimensional cutting forces, and the uncut chip th thickness is calculated by following the movements of the position of the center of a cutter, which varies with the nominal feed, cutter deflection and runout. For general implementation to a real machining, this paper presents the method that determines constant cutting force coefficients, irrespective of the cutting conditions or cutter rotation angles. In addition, this study presents the approach which estimates runout-related parameters. the runout offset and its location angle, using only one measurement of cutting forces. For more accurate cutting force predictions, the size effect has to be considered in the cutting force model. In this paper, two approximate methods are suggested since the strict approach is practically impossible due to a measurement problem. The size effect is individually considered for narrow and wide cuts.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.725-730
• /
• 2005

In case of the national roads which is opened in the past, there are carried out the expansion and improvement for enlargement of the traffic demand by industrial development and safety road operation to narrow of road width and serious change of the road alignment with effect of topography and graphical features of a mountain. A protection method using vegetation in the cut-slope has been constructed for harmony of ambient environment after cutting the slope recently. But it requires a study because the surface lose and the failure have been occurred in the large cut-slope which is covered by vegetation. In this study it was presented a countermeasure and examined a stability of contained uncertainty in the cut-slope according to the failure example of the cut-slope which is covered by vegetation. The additional research will be necessary against the development of the investigation technique which executes the stability investigation of the cut-slope which is covered by vegetation.

• 한국방재학회:학술대회논문집
• /
• 2008.02a
• /
• pp.589-592
• /
• 2008

National Road No.24 connects Ulju-gun in Ulsan Metropolitan City and Milyang city in south Gyongsang Province. The width of the road is small and narrow and many of the dangerous cut slopes are distributed along the way. In 2002, the government officer carried on the brief exploration about road cut slopes, and KICT conduct a detailed additionally investigations 57 dangerous cut slope sites of them. We gained a variety of information of the each slope such as length, slope, discontinuites et al.

• Journal of the Korean Geosynthetics Society
• /
• v.10 no.4
• /
• pp.11-18
• /
• 2011

In this study, the reinforcing effect of geogrids in the narrow backfill by sand was experimentally studied. In the model tests, the size of space and the slope of the cut off slope were varied out. The resultant and the distribution of lateral earth pressure were measured. Width of backfill space varied 10 cm, 20 cm, 30 cm at the lower wall level and angle of the cut off slope varied $90^{\circ}$, $75^{\circ}$, $60^{\circ}$. Geogrids were installed in the backfill. Measured results showed that the distribution of the lateral earth pressure due to the narrow backfill developed in a arching shape. And the earth pressure was reduced due to the reinforcement of the backfill by geogrid. geogrid helps reduction of lateral earth pressure.

• ETRI Journal
• /
• v.27 no.3
• /
• pp.304-311
• /
• 2005

We report on the fabrication of an AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) using a dielectric-defined process. This process was utilized to fabricate $0.12\;{\mu}m\;{\times}\;100 {\mu}m$ T-gate PHEMTs. A two-step etch process was performed to define the gate footprint in the $SiN_x$. The $SiN_x$ was etched either by dry etching alone or using a combination of wet and dry etching. The gate recessing was done in three steps: a wet etching for removal of the damaged surface layer, a dry etching for the narrow recess, and wet etching. A structure for the top of the T-gate consisting of a wide head part and a narrow lower layer part has been employed, taking advantage of the large cross-sectional area of the gate and its mechanically stable structure. From s-parameter data of up to 50 GHz, an extrapolated cut-off frequency of as high as 104 GHz was obtained. When comparing sample C (combination of wet and dry etching for the $SiN_x$) with sample A (dry etching for the $SiN_x$), we observed an 62.5% increase of the cut-off frequency. This is believed to be due to considerable decreases of the gate-source and gate-drain capacitances. This improvement in RF performance can be understood in terms of the decrease in parasitic capacitances, which is due to the use of the dielectric and the gate recess etching method.

• Journal of Digital Convergence
• /
• v.16 no.10
• /
• pp.479-484
• /
• 2018

This study is an attempt to analyze the changes and morphological analysis of the one length hair style of women in the Imperial Japanese colonial period, and the purpose of this study is to analyze the components of hair design such as shape, texture, and color based on the precedent and the book and to make possible various styles of one length hair style cut. From the results of this study, one length hair style showed the outline shape with no step height of cut length, natural hair texture and natural hair color in 1910s to 1920s. In the 1930s, the one length hair style showed a slight cut length step height and a slight discoloration using a diamond shape, a narrow wave of natural texture, hydrogen peroxide or oxygenated water. In the 1940s, one length hair style did not find any singularity to pursue brilliant beauty(美) in terms of form, texture, and color. This study may enable a deep and detailed follow up study on one length hair style, and will be a cornerstone for the development of basic data of hair beauty education and trend of new mode.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.12
• /
• pp.1201-1211
• /
• 2014

The purpose of this paper is to present the aperture cut-off filter for reduction of electromagnetic field penetration through a slot in conducting screen. The reduction characteristics of electric field penetration by the aperture cut-off filter are considered. In order to establish the concept of the aperture cut-off filter, the integral equation on the slot aperture field distribution is derived and solved by method of moments, and the reduction characteristics of penetration electric fields for the incident plane wave are calculated. The numerical results showed that the aperture cut-off filter for reduction of electric field penetration through the slot can be realized. To check the validity of the concept of an aperture cut-off filter and the theoretical analysis, the calculated electric field penetration of the metallic wall with narrow slot were compared with the experimental results.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.376-379
• /
• 2003

In this raper, proposed easy half-wavelength LPF and acceptor structure in actuality manufacture using EBG (Electromagnatic Bandgap) structure for application of micro-strip circuit. Because conventional half-wavelength LPF and acceptor is narrow line-width of High impedance, actuality manufacture is difficult. Width that in proposed structure narrow microstrip line of High impedance EBG structure use and has equal impedance embodied to wide microstrip line. Also, it is seen that actuality manufacture is available applying to half-wavelength LPF that have cut-off Frequency of 3GHz.

• Proceedings of the IEEK Conference
• /
• 2002.06b
• /
• pp.249-252
• /
• 2002

we have studied the characteristics of PHEMT's with gate recess etching method. The DC characterization of PHTMT fabricated with the wide single recess methods is a maximum drain current density of 319.4 ㎃/mm and a peak transconductance of 336.7 ㎳/mm. The RF measurements were obtained in the frequency range of 1~50GHz. At 50GHz, 3.69dB of 521 gain were obtained and a current gain cut-off frequency(f$_{T}$) of 113 CH and a maximum frequency of oscillation(f$_{max}$) of 172 Ghz were achieved from this device. On the other hand, a maximum drain current of 367 mA/mm, a peak transconduclancc of 504.6 mS/mm, S$_{21}$ gain of 2.94 dB, a current gain cut-off frequency(f$_{T}$) of 101 CH and a maximum frequency of oscillation(f$_{max}$) of 113 fa were achieved from the PHEMT's fabricated by the .narrow single recess methods.methods.

• Journal of the Korean Society of Safety
• /
• v.14 no.4
• /
• pp.114-119
• /
• 1999

When NaOCl was generated and put into sea-water cooling machine in order to overcome the biological hindrances against sea-water cooling machine, it was converted into metallic ion, particularly Ca and Mg, as a hydrate in sea-water and is to stick to electrolyte as a side reaction. This phenomena make the distance between the electrolytes narrow to decrease the flow rate, which induces the local vortex flow which erodes the pole plate. Moreover, this increases the resistance of the electrolyte as well as voltage to decrease the electrolytic efficiency, which has curtailed a chlorine yield and caused a pole plate cut. We are able to overcome these problems by chemical cleaning and intend to extend the life-time of electrolyte and to increase output of the sea-water electrolysis facilities by studying optimal policy regarding chemical cleaning of electrolytic cell. Cleaning time of electrolytic facilities is determined when both increase in electrolytic efficiency and decrease in pole-plate voltage are 10%. At this time as operating current of electrolytic facilities is high, operating time is diminished. Whereas, parameter of end point determination according to cleaning is Mg ionic concentration in solution. When we use Cleaner as a 7wt% HCl, cleaning time is about 80min proper. We are able to maintain pole plate performance by protecting against pole plate cut by means of electrolytic by-product, improve operating rate of facilities, and cut down on maintenance expenditure after acidic cleaning.