• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.1
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• pp.53-61
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• 2015

This paper presented the nonlinear behaviors of the single-layered lattice dome, which is widely used for the long-span structure system. The behaviors were analysed through the classical shell buckling theory as the single-layered lattice dome behaves like continum thin shell due to its geometric characteristics, and finite element analysis method using the software program Nastran. Shell buckling theory provides two types of buckling loads, the global- and member buckling, and finite element analysis provides the ultimate load of geometric nonlinear analysis as well as the buckling load of Eigen value solution. Two types of models for the lattice dome were analysed, that is rigid- and pin-jointed structure. Buckling load using the shell buckling theory for each type of lattice dome, governed by the minimum value of global buckling or member buckling load, resulted better estimation than the buckling load with Eigen value analysis. And it is useful to predict the buckling pattern, that is global buckling or member buckling.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1130-1135
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• 2015

The bond pull test is the most widely used technique for the evaluation and control of wire bond quality. The wire being tested is pulled upward until the wire or bond to the die or substrate breaks. The inspector test strength of wire by manually and it takes around 3 minutes to perform the test. In this paper, we develop a 3D vision system to measure 3D position of wire. It gives 3D position data of wire to move a hook into wires. The 3D measurement method to use here is a confocal imaging system. The conventional confocal imaging system is a spot scanning method which has a high resolution and good illumination efficiency. However, a conventional confocal systems has a disadvantage to perform XY axis scanning in order to achieve 3D data in given FOV (Field of View) through spot scanning. We propose a method to improve a parallel mode confocal system using a micro-lens and pin-hole array to remove XY scan. 2D imaging system can detect 2D location of wire and it can reduce time to measure 3D position of wire. In the experimental results, the proposed system can measure 3D position of wire with reasonable accuracy.

• The Research Journal of the Costume Culture
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• v.25 no.2
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• pp.159-174
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• 2017

The study uses lists of wedding gifts used from old Korean documents written in Hangeul in the western Gyungnam province during the 20th century. The study analyzed four lists of wedding gifts from the Muncheongak archive and two lists from the archive of ancient document. This analysis found that clothing accounts for the majority of the items in the lists, and items such as furniture, jewelry, household goods, and medical materials were also recorded. That the furnishings were commonly prepared by the groom's side, and the fact that the number of jeogori was higher than the number of skirt, speaks to the unique wedding custom of Gyeongsang province. While the groom's list of wedding gifts included a record of the bride's ornaments, jewelry, and furnishings in the bride's list, the groom's nickel top-knot pin was only included as an ornament. In the list of wedding gifts between brothers, the gifts for the eldest son differed from those for the third son in terms of number and price. The list of wedding gifts between father and son illustrates how economic development and changing times wedding custom. The lists of wedding gifts in the old Korean documents shed light on the oral research into 20th century wedding custom, which will be used as basic data in researching and reproducting the wedding culture and life conditions of the time.

• Korean Journal of Optics and Photonics
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• v.10 no.1
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• pp.73-79
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• 1999

Semiconductor optical switch modules of 1$\times$2, 1$\times$4, and 4$\times$4 types for 1550 nm optical communication systems were fabricated by using laser welding technique, embodying in 30-pin butterfly package. For better coupling efficiency between switch chip and optical fiber, tapered fibers of 10~15mm lens radii were used, which provided up to 60% optical coupling efficiency. With the help of new laser hammering process, we could recover the lost optical power almost completely up to average 82% of initially obtained power. The fabricated optical switch modules showed good thermal stability of less than 5% degradation even after 200 times thermal cycling test. The 2.5 Gbps optical transmission characteristics of the 4$\times$4 switch module showed low sensitivities of less than -30dB for all possible switching paths. The transmission penalties of 1$\times$2 switch module at $10^{-10}$ BER were 0.6dB and 0.7dB for 50Xm and 90 Km optical fibers, respectively.

• Journal of Technologic Dentistry
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• v.31 no.1
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• pp.63-74
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• 2009

Partial or complete prosthesis is needed when teeth are lost due to various kinds of reason. Artificial teeth recover occlusion instead of natural teeth. Artificial teeth are required of esthetics, fragile resistance and abrasive resistance. Artificial tooth is made of acrylic resin or porcelain. Nowadays, acrylic resin artificial teeth are mainly used. Acrylic resin teeth are occluded with natural teeth, gold alloy, Ni-Cr alloy or porcelain etc. Acrylic resin teeth have similar translucency, gloss of natural teeth. And it has good chemical bond with denture base material, but it has low wear resistance. The aim of this study is to compare wear resistance among several denture teeth(Endura, SR-orthosit-PE, Planustar) and between artificial resin denture teeth and opposing 3 restorative materials(gold, Ni-Cr alloy, porcelain). Wear tests were conducted with a rotating wear testing apparatus(pin-on-disk type wear tester) under conditions of rpm 180, 75 minutes and constant loading of 50N. The upper part was the cusp of maxillary first molar and the lower part was a disk type restorative materials. To make similar oral environment, water was supplied continually. The acrylic resin teeth wear was determined by weighing the cusp each 5 minutes during 75 minutes test. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces. The results were as follows: 1. Wear rates of acrylic resin teeth opposing to the restorative materials were high in order of Porcelain, Gold, Ni-Cr alloy (p<.05). 2. Wear resistance rate opposing to the Porcelain disk, was shown in order of Endura, SR-orthosit-PE, Planustar. The wear rate of opposing to porcelain disk was above two times more than that of other groups (p<.05). 3. Wear resistance rates opposing to the Gold, Ni-Cr alloy disk, was shown in order of Endura, SR-orthosit-PE, Planustar (p<.05). 4. A degree of the surface hardness is directly proportional to the degree of wear resistance. There are statistically significant differences between each groups (p<.05).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.698-703
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• 2007

In this paper, a novel impedance tuner using a directional coupler is proposed. The design topology is analyzed by signal flow graph(SFG) and shows advantages compared with conventional single and double stub methods from the view points of easy implementation and wide tuning range, respectively. This impedance tuner consists of ten switches and its $2^{10}$ tuning points are distributed uniformly on the whole Smith chart. The measured maximum magnitude of the reflection coefficient is 0.9. And the fabricated impedance tuner has a wide bandwidth from 1.8 to 2.2 GHz. Using this impedance tuner, we did a load-pull measurement of a power transistor.

• Fashion & Textile Research Journal
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• v.22 no.5
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• pp.686-695
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• 2020

The present study evaluated the manual dexterity and usability of conductive gloves when operating touchscreen devices in the cold. Twelve male subjects (23.3±1.5 years in age) participated in three experimental conditions: no gloves, fabric conductive and lambskin conductive gloves. Manual dexterity was tested using both Purdue Pegboard (PP) and ASTM dexterity tests at an air temperature of 5℃ and air humidity of 30%RH. Glove usability was tested through the following touchscreen tests: tap, double tap, long tab, drag, flick, and multi-touch. The results showed that manual dexterity according to the PP (2.5 mm of a pin diameter) and ASTM tests (8 mm of a stick diameter) was worse for the two glove conditions than for the no glove condition (p<.005). PP dexterity was better for the fabric glove condition than for the lambskin glove condition (p<.05); however, there was no difference in ASTM dexterity between the two glove conditions. Hand and finger skin temperatures were higher for the glove conditions than the bare hand condition (p<.05), with no differences between the two glove conditions. The touchscreen usability was the best for the no glove condition, followed by fabric gloves (p<.05). Wearing either fabric or lambskin gloves diminishes hand dexterity while maintaining hand and finger temperatures at higher levels. For improved hand dexterity in dealing with small numbers, letters on a touchscreen in cold environments, we recommend wearing fabric conductive gloves rather than lambskin conductive gloves.

• Archives of Reconstructive Microsurgery
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• v.10 no.2
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• pp.131-136
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• 2001

Purpose : The sensory radial forearm flap is used to recover the soft tissue defect of hand and foot. The aim of this study is to evaluate the results after sensory reconstruction using sensate radial forearm flaps. Materials and Methods : There were 9 cases of 8 patients (6 males and 2 females). The 7 cases of 6 patients were donated to foot, the 2 cases of 2 patients to hand. At operation, the ages of them ranged from 18 to 63 years (mean: 37.9 years). Sensory evaluation was performed using percentage(%) of responding area to the pinprick test and the static and moving two-point discrimination test (s-2PD and m-2PD). Results : The mean percentage of responding area to the pin prick test was 48.5%. The mean s-2PD and m-2PD of recipient hands were 37.2 mm and 28.8 mm. The mean s-2PD and m-2PD of recipient feet were 46.7 mm and 45.0 mm. The mean s-2PD and m-2PD of controls were 23.5 mm and 19.7 mm. Conclusion : All the recipients were less sensitive than the control, but the recipient hands more sensitive than the recipient feet. Although the small numbers were studied, the results suggested that the recovery of sensation in the innervated flaps was influenced by the recipient nerve. So the donor nerve seems to be selected as more sensitive and more distal nerve of donor site for better outcome.

• Toxicological Research
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• v.21 no.1
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• pp.45-49
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• 2005

The purpose of this study is to evaluate the free radical scavenging ability and xanthine oxidase inhibitory activity of a complex herbal bath consisted of Artemisiae argyi folium, Angelicae sinensis radix, Ligustici wallichii radix and Angelicae tuhuo radix, and its potential irritation response were also tested for safety use in the rabbits. For antioxidative activity, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the complex herbal bath were examined at five different concentrations (0, 250, 500, 1000 and 2000 ㎍/ml). The concentration of the complex herbal bath required for scavenging DPPH free radical by 50% was 897.2 ㎍/ml. In the inhibition of xanthine oxidase (XO) activity, the concentration of the complex herbal bath required for 50% of inhibition was 221.4 ㎍/ml. In the skin irritation study in rabbit, all animals survived for the duration of the study and the examined skin exhibited no edema, erythema, and eschar formation. In the ocular irritation study in rabbit, after application of the sample to eyes, all of the eyes were normal. In summary, the complex herbal bath has potent antioxidant effects against the DPPH radical and XO and was considered to be a non-irritation bath for safety use.

• Journal of Korean Society of Steel Construction
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• v.24 no.1
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• pp.73-80
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• 2012

The adoption of a composite beam system is regarded as a simple but effective solution because it improves the overall stiffness, strength and stability of the structure by welding shear studs. However, welding shear studs poses problems including electric shock and weld defects. Mechanical methods have emerged as an alternative to metallurgical methods for connecting the H-beam and shear connector. Four specimens were tested in order to compare the structural behavior of the proposed composite beams with that of the classical composite beam given the condition of horizontal loading. With the original composite beam (FCB-SB specimen) using stud bolts, hysteresis loops are stable, but its strength decreased with the crashing of the concrete slab around the column. The suggested composite beams using shear connectors also yielded stable hysteresis loops. Consequently, use of the suggested composite beams instead of the original composite beam are recommended.