• The Journal of Engineering Geology
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• v.19 no.4
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• pp.493-499
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• 2009

Recently, the construction of Concrete Faced Rockfill Dam (CFRD) is increasing because rock material resources are plenty in Korea. Bedding zone in the CFRD is necessary enough bearing capacity to support the concrete face slab uniformly and enough impermeability to prevent the loss of fine soils in case of leakage from the concrete slab face. Therefore, cut-off the water leakage in bedding zone securely is the key factor influencing the safety of CFRD. Tested materials satisfied with the specification of particle size distribution at the Bedding Zone area are chosen for conducting permeability tests, which are done to evaluate the property of cut off the materials. Based on the test results, the effects of cut off the materials are investigated by considering the coefficient of permeability, the soil particle distribution, and the dry unit weight. Especially, the relationships between coefficient of permeability with effective size(D10), dry unit weight, and weight passing percent the No.4 sieve are suggested, and also the variation of coefficient of permeability with time are proposed.

• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.617-626
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• 2014

In this paper, experiments for the evaluation of tensile strength of steel plate with bolt hole and bearing strength of bolted connection were performed, where bolt holes were punched by drilling and oxygen torch, respectively. For the tensile tests, drilled and oxygen torch punched steel plate specimens of 10mm and 15mm thickness were made from structural angles and H-shapes, respectively. For the bearing strength evaluation, test specimens were fabricated with base plates and splice plates those were also punched by drilling and oxygen torch, respectively. The Vicker's hardness were measured around the bolt hole to investigate material property change due to heat effect by oxygen torch cut. Numerical analysis was also performed to investigate the bearing strength of bolted joints due to the increase of hardness around the bolt hole by oxygen torch cut.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.5
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• pp.925-932
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• 2001

The influence of ultraviolet(UV)-ray in sun light on human skin has been noted. Textiles can provide protection against harmful UV-radiation. Normally UV-absorbing finishes are used to get better protection. The purpose of this study is to evaluate the UV-cut properties of cotton fabrics treated with UV-absorber. 2,2-dihydroxy-4,4-dimethoxbenzophenone, as UV-absorber was applied to 100% cotton fabric. Reagents added in finishing solution were Triton X-100, polyethylene glycol 400, and $MgCl_2{\cdot}6H_2O$, and C.I. Direct Red 81. Both untreated and treated cotton fabrics were exposed to a xenon arc lamp for 20 and 80 hours. UV absorption spectra of finishing solutions and UV transmission spectra of fabrics were measured by the UV/VIS spectrophotometer. The results of this study can be summarized as follows. The results of this study can be summarized as follows. Absorption and the related transmission spectra were modified in a controlled way with UV-absorber. Absorption effect of UV-absorber was improved by adding Triton X-100, PEG 400, and $MgCl_2{\cdot}6H_2O$ in finishing solution. The UV absorption of finishing solution was in the following order: U/D/T/P/M>D/T/P/M> D/T> D/P, D>U/T/P/M>U/T>T/P/M>T. The UV transmittance of cotton fabrics was remarkably decreased by the application of UV-absorber and additives. The UV-cut properties were most improved by the application of U/D/T/P/M.

• Membrane Journal
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• v.23 no.2
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• pp.176-184
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• 2013

To investigate the performance of VOC separation, composite hollow fiber membrane was prepared which composed of poly (ether imide) support prepared by phase separation method and poly (dimethylsiloxane) coating active layer. The performances of the membranes for the application of recovery process in terms of their morphology, gas permeance test for $N_2$ and $O_2$ gases. Durability against benzene, toluene and xylene was also investigated. And permeation test for multi-component VOCS through the membrane with different feed concentration and stage-cut were investigated. Permeance of PEI supported membrane and the membranes coated with PDMS decreased from 45,000 GPU to 63 GPU and 49,450 to 30 GPU for $N_2$ and $O_2$, respectively. Recovery efficiency and concentration of VOCs in permeate increased with decreasing stage-cut. VOCs concentration in permeate proportionally increased with increasing feed concentration but concentration ratio and recovery efficiency showed any noticeable changes with feed concentration change.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.5
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• pp.623-631
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• 2011

Light emitting diodes (LEDs) which can produce uniform luminescence need a very difficult and complex procedure because LEDs have strong and straight optical property. One of the major parameters for LED production is the determination of the viewing angle. However, in the present, there is still no available production technology to measure LED viewing angle and optical property. In this study, we developed a five-side LED viewing angle and optical property measurement system, having a source meter that uses a high speed switching photo relay instead of a mercury relay. This new measurement system can measure the viewing angle at a very high accuracy of ${\pm}0.66^{\circ}$. This new technology presents a great potential for fast and reliable LED mass production, which can significantly cut down the cost from savings in production time.

• Explosives and Blasting
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• v.17 no.2
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• pp.45-51
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• 1999

To find out the characteristics and trend of dust fall in open cut limestone mine in-situ measurement and wind tunnel tests were carried out. In-siti measurement was done by two dust fall samplers at the Halls mine for 60 days. The laboratory test was done in the 100m long temporary wind tunnel installed at the yard of the institute. The most of dust falled within 25m form the dust source and only less than 0.5% defused up to over 100 meters. It was known that the dust fall at 100m away from souces were negligible.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.4
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• pp.466-475
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• 2011

The dyeing properties of protein fiber with pine needles colorants were studied through an investigation of the effect of dyeing conditions such as dye concentration, dyeing temperatures and time on dye uptakes, effect of mordants, and color change. In addition, the various colorfastness of dyed silk and wool fabrics were evaluated for practical use. The antimicrobial ability, ultraviolet-cut ability, and deodorant ability were also estimated. The dye uptake increased as the dyeing concentration increased and this enabled the obtainment of the Langmuir absorption isotherm. The dye uptake increased as the dyeing time and temperature increased. Pine needles colorants showed relatively good affinity to protein fiber and produced a yellow color. Post-mordanting was more effective than the pre-mordanting, and the dye uptake of fabrics improved by mordanting. Except for washing, the colorfastness of dyed fabrics showed a low rating. However, the colorfastness to light and the dry cleaning of fabrics mordanted with N.Cu, and the friction fastness of fabrics mordanted with Cu improved. The guide fabrics showed very good antimicrobial abilities of 99.9%; in addition, the ultraviolet-cut ability and deodorant ability improved in fabrics dyed with pine needles extracts.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.15-21
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• 2004

The machining process of ceramics can be characterized by cracking and brittle fracture. In the machining of ceramics, edge chipping and crack propagation are the principal reasons to cause surface integrity deterioration. Such phenomenon can cause not only poor dimensional and geometric accuracy, but also possible failure of the ceramic parts. Thus, traditional ceramics are very difficult-to-cut materials. To overcome such problems, in this paper, h-BN powder, which gives good cutting property, is added for the fabrication of machinable ceramics by volume of 5, 10, 15, 20, 25 and 30%. The objectives of this paper is to evaluate the fracture phenomenon of the tungsten carbide tool and the variation of surface integrity of the manufactured machinable ceramics under various cutting conditions during end mill machining With CNC machining center.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.4
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• pp.34-41
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• 2003

A new technique for detecting parametric faults in mixed signal circuits is proposed Pseudo-random sequence from linear feedback shift register(LFSR) is fed to circuit-under-test (CUT) as stimulus and wavelets are used to compact the transient response under this stimulus into a small number of signature. Wavelet based scheme decomposes the transient response into a number of signal in different frequency bands. Each decomposed signal is compacted into a signature using digital integrator. The digital pulses from LFSR, owing to its pseudo-randomness property, are almost uniform in frequency domain, which generates multi-frequency response when passed through CUT. The effectiveness of this technique is demonstrated in our experimental results.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.3
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• pp.336-346
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• 2011

Dyeing properties of protein fiber with bamboo colorants were studied by investigating the effect of dyeing conditions such as dye concentration, dyeing temperatures, times on dye uptakes, effect of mordants, and color change. The various colorfastness of dyed fabrics were evaluated for practical use. In addition, the antimicrobial ability, ultraviolet-cut ability, and deodorant ability were estimated. The dye uptake increased as the dyeing concentration increased. Bamboo colorants showed relatively good affinity to protein fiber and produced a yellow color. Dye uptake increased as the dyeing time and temperature increased. Post-mordanting was more effective than pre-mordanting. Mordants, Fe and N.Fe, were effective for increasing dye uptake. The color of fabric mordanted with Cu and N.Cu changed to GY. Colorfastness of dyed fabrics showed a relatively good rating, and mordanting had no significant effect on colorfastness. Dyed silk fabric showed very good antimicrobial abilities of 99.9%. Also, ultraviolet-cut ability and deodorant ability were improved in silk fabric dyed with bamboo extracts.