• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.459-467
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• 2005

This study focuses on the development of a new method of H-shaped beam-to-square column connection with an outer diaphragm and a field welding. The specific type of beam-to-column connection with an external stiffener, using field welding, is proposed. The structural behavior of this connection was examined experimentally. Two loading type tests were conducted under the experimental parameters given as details. First described was the symmetrical loading test, which supported both ends or a beam simply and applied a load from the column to the pend (What does this mean?) to investigate a fundamental characteristic of this connection. Further described was the anti-symmetrical loading test, which carried out simple support of the column'stop end and the column base, and applied a load from both ends of a beam to investigate the structural performance of this connection. From the results, it is clear that the external- stiffener-type connection proposed in this paper is the reliable connection method.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.3
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• pp.88-97
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• 2009

The vacuum die casting techniques can diminish the porosity of products and provide better surface appearance by the ordinary high pressure die casting process. The vacuum system can also reduce the cold laps in the die casting process and minimize the overflow pockets of the die. The vacuum system does not need high pressures to die cast compared to the ordinary die casting process, and so enables die casting of large parts for a given machine size. Parts made by the vacuum system have higher strength and more elongation than parts made by the ordinary die casting systems. In this paper, we designed and produced the Magnesium seat frames using the vacuum die casting processes. The new Magnesium seat frame was designed to satisfy safety regulations. Some safety test procedures of the seat frame were simulated by the finite element method. We obtained 10% weight reduction by design modification of seat frames compared to the current model. Flow simulations were carried out to minimize the trial and error in producing the parts. The die casted parts using vacuum systems resulted in better mechanical characteristics and no defects compared to those without vacuum systems.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.116-125
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• 2002

Semi-Solid Diecasters usually carry out the Semi-Solid diecasting experiments before producing new casts. At the Semi-Solid diecasting stages, the runner-gate part has been always repeatedly corrected, which leads to a tedious processing time and increased processing cost. A large amount of experience is essential in manual assessment and if the design is defective, much time and a great deal of efforts will be wasted in the modification of the die. In this study, design system has been developed based on design database. In addition, gate experiment for gating system design has been carried out to append the database. It is possible for engineers to make efficient gating system design of Semi-Solid diecasting and it will result in the reduction of expenses and time to be required. The detailed contents of the research are described in the followings.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.1
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• pp.29-36
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• 1999

A field experiment of the leeway of person-in-water(man with wetsuit) was conducted during October 1997∼ April 1998. The experiment area was northeast side of Cho Do island in Pusan. The college students whose weight ranges 60∼87 kg, height 170∼178 cm were actually drifted for the experiment. The person-in-water wore 5 mm neoprene diving wetsuit to prevent heat loss of the body. The current near the target was measured using a colored vinyl bag. To compare the result a scuba diver equipped with scuba gear and with his BC(buoyancy compensator) fully inflated was drifted alongside. The average leeway speed of man with wetsuit and that of scuba diver were about 0.4 percent and 1.3% of the 10 m wind speed above the water respectively.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.132-133
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• 2007

$In_xGa_{1-x}N/In_yGa_{1-y}N$ 다중 양자우물 녹색 발광 다이오드에 2차원 광자 결정을 이용하여 음극선 발광의 향상을 관찰 하였다. 정사각형 배열의 2차원 광자 결정의 주기와 격자 상수는 200/500 nm 이고 전자빔 리소그래피로 광자결정 패턴을 제작한 후, 플라즈마 건식 식각법으로 패턴을 구현하였다. 식각 시간의 차이를 둔 구현된 패턴의 홀 깊이는, 각각 ${\sim}69nm,\;{\sim}99nm,\;{\sim}173nm$ 이었다. 전계 방사 주사 현미경 측정 결과, 형성된 홀은 끝이 잘린 역전된 원뿔 모양으로 식각 되었다. 식각 된 홀의 깊이에 따라 광자 결정이 있는 부분이 없는 부분보다 최대 ${\sim}30$배 많은 광자가 검출 됨을 확인하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.34-41
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• 2021

Interventional radiology and minimally invasive surgery both require a precisely shaped microcatheter. Microcatheters are manufactured using polymer extrusion processes with a die and puller. The manufacturing parameters and die geometry greatly influence the profile of the extrudate and designing dies using a trial-and-error process is expensive and requires a lot of time. Therefore, predicting the profile of the extrudate is important for manufacturing microcatheters. This study investigates the effects of die design and geometry on the profile of the extrudate. The profiles of the extrudate are predicted using ANSYS Polyflow with respect to the different die geometries. The outer and inner diameters and wall thickness of the predicted extrudate are compared to those of a target extrudate. The die swell of melt polymer and the effect of the pulling are both examined. Optimized die designs are suggested for manufacturing the target extrudate.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.225-235
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• 2017

In this study, we investigated the effect on the increase of In vitro skin permeation experiments and In-vivo skin whitening efficacy using a O/W nanoemulsion produced via PIC(Phase Inversion Composition) with 1,3-di(pentyloxyl)benzene. skin permeation experiments of RS-nanoemulsion formulated with selected condition was evaluated compared to mineral oil containing 1,3-di(pentyloxyl)benzene and normal O/W type RS-emulsion. Compared to mineral oil with 1,3-di(pentyloxyl)benzene and RS-emulsion. RS-Nanoemulsion has a statistically significant high percutaneous absorption in terms of index substance, which is 1,3-di(pentyloxyl)benzene. In vivo test were prepared in the system of O/W cream containing RS-nanoemulsion. There was no adverse reactions in both samples. After 8 weeks, the subjects was evaluated by a dermatologist's scoring and Chromameter. In conclusion, the testing product showed statistically improvement (p<0.05) compared to the controlled product and proved its whitening efficacy.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.957-964
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• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.

• Economic and Environmental Geology
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• v.47 no.1
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• pp.1-15
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• 2014

The Bobonaro m$\acute{e}$lange is one of the youngest syn-collisional m$\acute{e}$langes, located between the Indo-Australian and Eurasian plates. The m$\acute{e}$lange has formed in association with a collision between the Australian continental margin and the Banda arc initiated in Neogene. The Suai area at the southern part of Timor is a good place to examine the genetic relationship between the m$\acute{e}$lange and other rock sequences because various tectonostratigraphic units coexist in the area. In this study, we present the structural characteristics and spatial distribution of the Bobonaro m$\acute{e}$lange investigated as a part of 1:25K scale geologic mapping in the area, and discuss on the origin of the m$\acute{e}$lange. The Bobonaro m$\acute{e}$lange in the Suai area is composed of unmetamorphosed clay matrix and blocks of various lithologies. The clay matrix mainly is reddish brown or greenish gray in colour, and has scaly texture. Most blocks are allochthonous, but mostly derived from nearby formations. Based on the internal structure and relationship with surrounding rocks, the Bobonaro m$\acute{e}$lange is genetically classified into 1) diapiric m$\acute{e}$lange; 2) tectonic m$\acute{e}$lange; and 3) broken formation. The spatial distribution of the Bobonaro m$\acute{e}$lange indicates that it intruded all pre-collisional units including the lower Australian continental margin unit(Gondwana megasequence) and the Banda arc unit. Taking the field evidences and previous genetic models into consideration, the Bobonaro m$\acute{e}$lange is interpreted to be mainly formed as a diapiric m$\acute{e}$lange originated from Gondwana megasequence, consistently effected by faulting events. This study reflects that diapiric m$\acute{e}$lange is a significant component in recent accretionay-collision belts. It suggests that diapiric process should be considered as a main genetic factor even in ancient m$\acute{e}$lange.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.9
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• pp.661-667
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• 2018

Tactical communication radio systems that employ software defined radios(SDRs) have been developed for achieving high-speed data transmissions and voice communications. Such systems possess multiband and multichannel features, and can potentially replace several existing radio systems. This paper proposes a design for wideband antennas by incorporating a diplexer matching network for tactical vehicles. The proposed antenna design includes two radiators(upper and lower) and a diplexer matching network connected to the end of the feed line such that the LC matching networks are interleaved in the lower radiator and spring mount. By employing the diplexer matching network, the designed antenna can perform wideband impedance matching for the fifty ohm feed line. The designed LC networks aid in varying the effective electrical length of the antenna according to the operation frequency. The primary objective behind adjusting the electrical length is to vary the current distribution above and below the LC networks. The proposed antenna was fabricated and tested in an open site. The obtained evaluation results show that the designed antenna can achieve a relative bandwidth of 190% with a VSWR value of 3.5:1, and can attain good antenna gains over VHF and UHF bands.