• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.193-197
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• 2005

This paper presents a method by which multiple holes of ultra small size can be punched simultaneously. Silicon wafers were used to fabricate punching die. Workpiece used in the present investigation were the rolled pure copper of $3{\mu}m$ in thickness and CP titanium of $1.5{\mu}m$ in thickness. The metal foils were punched with the dies and arrays of circular and rectangular holes were made. The diameter of holes ranges from $2-10{\mu}m$. The process set-up is similar to that of the flexible rubber pad forming or Guerin process. Arrays of holes were punched successfully in one step forming. The punched holes were examined in terms of their dimensions, surface qualities, and potential defect. The effects of the die hole dimension on ultra small size hole formation of the thin foil were discussed. The optimum process condition such as proper die shape and diameter-thickness ratio (d/t) were also discussed. The results in this paper show that the present method can be successfully applied to the fabrication of ultra small size hole array in a one step operation.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.1
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• pp.1-8
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• 2019

In this study, the effectiveness of a multi-action hybrid damper (MHD) composed of lead rubber bearing (LRB) and friction pad was verified in terms of seismic performance improvement of a frame structure. The LRB and the friction elements are connected in series, so the LRB governs the intial small deformation and the friction determines large deformation behavior. Cyclic loading tests were conducted by using a half scale steel frame structure with the MHD, and the results indicated that the structure became to have the stable trilinear hysteresis with large initial stiffness and first yielding due to the LRB, and the second yielding due to the friction. The MHD could significantly increase the energy dissipation capacity of the structure and the hysteresis curves obtained by tests were almost identical to the analytically estimated ones.

• Geomechanics and Engineering
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• v.30 no.3
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• pp.273-280
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• 2022

A certain amount of random vibration excitation to subway track is caused by subway operation. This excitation is transmitted through track foundation, tunnel, soil medium, and ground building to the ground and ground structure, causing vibration. The vibration affects ground building. In this study, the results of ANSYS numerical simulation was used to establish back-propagation (BP) neural network model. Moreover, a back-propagation neural network model consisting of five input neurons, one hidden layer, 11 hidden-layer neurons, and three output neurons was used to analyze and calculate the vertical Z-vibration level of New Capital's ground buildings of Qingdao Metro phase I Project (Line M3). The Z-vibration level under different working conditions was calculated from monolithic roadbed, steel-spring floating slab roadbed, and rubber-pad floating slab roadbed under the working condition of center point of 0-100 m. The steel-spring floating slab roadbed was used in the New Capital area to monitor the subway operation vibration in this area. Comparing the monitoring and prediction results, it was found that the prediction results have a good linear relationship with lower error. The research results have good reference and guiding significance for predicting vibration caused by subway operation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.154-160
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• 2021

Recently, there have been increasing construction works carried out in urban centers, which are inducing frequent artificial vibration in the vicinity of existing structures due to such construction works. moreover, in case of industrial estates, vibration is induced due to operation of machines in the surrounding areas, thereby causing problems. meanwhile, in case of ordinary concrete that compose structure has low level of damping capability for vibration. accordingly, there are difficulties in blocking a wide range of vibrations delivered to the structures from outside including not only vibrations generated in the structures themselves but also ground vibration. recently, numerous studies are being carried out actively on high-damping system that markedly enhanced the damping performances of structures by utilizing polymer concrete in order to block the vibrations delivered to the structures through ground. therefore, this study compared the performances of polymer concrete with those of ordinary concrete, polyurethane pad and foamed rubber pad in order to review its performances in reducing ground vibration. for this purpose, review of FRF and vibration acceleration as dynamic characteristics was made. after comparative verification on the dynamic characteristics is made when polymer concrete and other aforementioned materials are applied to underground structures, the possibility of application of polymer concrete to structures is reviewed.

• The Journal of Korean Academy of Prosthodontics
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• v.21 no.1
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• pp.59-66
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• 1983

Distal extension partial dentures are supported by both the relatively rigid teeth and the resilient mucosa. So impression techniques of residual alveolar ridge in case of distal extension partial denture have particular importance in order to broad distribution of the masticatory force. McLean recognized the need for recording the tissues supporting distal extension partial denture base in functional form to equalize the resilient and non-resilient support, and this was called functional impression. Many investigators proposed various techniques of the functional impression for a distal extension partial denture, but only a little studies were performed about displacement of soft tissue under distal extension partial denture base. The purpose of this study is to investigate the amount of vertical displacement of the soft tissue under distal extension partial denture base by different functional impression techniques. Impression techniques used were Z.O.P. Impression, Selective Tissue Placement Impression, Functional Relining Impression. Measurement of the vertical displacement of soft tissue were made with Depth Gauge and Measuring Platform. A Anatomic Impression was used as a control. The results were tested statistically using 3 way ANOVA and Scheffe test. The followings were the results obtained from this study. 1. The greatest amount of soft tissue displacement was observed in the center of the retromolar pad. 2. No significant differences were found between the crest of alveolar ridge and the buccal shelf area. 3. The greatest soft tissue displacement was observed in Functional Relining Impression using Iowa wax, and the least displacement was observed in Selective Tissue Placement Impression using murcaptan rubber base. 4. No significant differences were found between finger pressure and biting pressure in Z.O.P. Impression, but greater displacement was observed by biting pressure than finger pressure in Functional Reling Impression.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1330-1336
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• 2015

It is necessary to study on acoustic and vibratory response of a MEMS resonant accelerometer before applying to military applications. In this paper, we analyze why the resonant accelerometer reacts to an acoustic wave and a high frequency vibration. And we describe experimental results on acoustic and vibratory response of the accelerometer. The accelerometer consists of a proof mass and a dual ended tuning fork. It is a differential resonant accelerometer with arranging a pair of accelerometers. The mode shape was analyzed to find out the input mode frequency by using a FEM simulation. Some experiments regarding the acoustic noise was carried out by using a tweeter and a microphone in the anechoic room. Results showed that the accelerometer reacted to the acoustic wave and vibration which had the input mode frequency as we had expected. We showed experimentally not only that the susceptibility of the accelerometer to an acoustic wave was 70 dB but also that the effectiveness of applying an acoustic absorber and a metal case was 20 dB, respectively. Also, we could minimize the vibratory response property of the accelerometer by installing a IMU with a silicone rubber mount pad.

• Earthquakes and Structures
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• v.7 no.6
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• pp.1001-1024
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• 2014

The size of spread footings was found to be unnecessarily large from some actual engineering practices constructed in Taiwan, due to the strict design provisions related to footing uplift. According to the earlier design code in Taiwan, the footing uplift involving separation of footing from subsoil was permitted to be only up to one-half of the foundation base area, as the applied moment reaches the value of plastic moment capacity of the column. The reason for this provision was that rocking of spread footings was not a favorable mechanism. However, recent research has indicated that rocking itself may not be detrimental to seismic performance and, in fact, may act as a form of seismic isolation mechanism. In order to clarify the effects of the relative strength between column and foundation on the rocking behavior of a column, six circular reinforced concrete (RC) columns were designed and constructed and a series of rocking experiments were performed. During the tests, columns rested on a rubber pad to allow rocking to take place. Experimental variables included the dimensions of the footings, the strength and ductility capacity of the columns and the intensity of the applied earthquake. Experimental data for the six circular RC columns subjected to quasi-static and pseudo-dynamic loading are presented. Results of each cyclic loading test are compared against the benchmark test with fixed-base conditions. By comparing the experimental responses of the specimens with different design details, a key parameter of rocking behavior related to footing size and column strength is identified. For a properly designed column with the parameter higher than 1, the beneficial effects of rocking in reducing ductility and the strength demand of columns is verified.

• Journal of Fashion Business
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• v.19 no.3
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• pp.31-42
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• 2015

The purpose of this study is to develop a new makeup-kit brand for education, analyzing customer satisfaction of makeup-kits used in makeup lessons provided by lifelong education centers of colleges. The research method is as follows. In order to understand the current status of the kits used in makeup lessons offered by lifelong education centers of colleges in South Korea, the study conducted a survey from October 10 of 2014 to October 31 via fax, telephone and e-mail targeting these 98 colleges that were open makeup-courses available in October 2014. As for an analysis technique, the study used a frequency analysis. In order to develop a makeup-kit brand, the study investigated these makeup-kits as well and presented a BI draft and a makeup-kit design that the study had created for itself using Photoshop CS6 and Illustrator CS4. According to findings of the survey, the students were not satisfied with kits that had too many items, were high in price and had poor case design. In the light of that, the study conducted to develop a low to middle priced makeup-kit ranging from 110,000 KRW and 150,000 KRW with approximately 26 items. In terms of a case design, black was a dominant color which would make the case feel simple and modern. Dimensions of a small size makeup-kit container were 22cm*35cm*37cm with a sponge and rubber pad proposed as product ideas. The study also worked on a BI design.

• Korean Journal of Acupuncture
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• v.18 no.1
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• pp.165-170
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• 2001

A rapid increasing in cultivation area due to favorable price temporarily and decreasing in consumer's demands caused by economic depressions recently, lead the price of Cynanchum wilfordii Hemsley to decline sharply. Thus, it may give rises to weakening of cultivation bases in Cynanchum wilfordii Hemsley. To investigate optimal mechanical peeling conditions of Cynanchum wilfordii Hemsley, protruded rubber, plastic pad, diamond shape's steel and palstic brush were introduced as blades and artificial stone, sand and small pebble were done as abrasives. The main results obtained were summarized as follows; 1. It took 2 minutes per 1kg in mechanical peeling of Cynanchum wilfordii Hemsley's raw root whereas 36 minutes in manual peeling and values of lightness showed more higher in manual peeling than in mechanical peeling. 2. Yield in combination of diamond shape's steel blade and sand abrasive showed the lowest at 89.9% among treatments and peeling rates in combination of diamond shape's steel blade and small pebble showed the highest at 71.3% in mechanical peeling. 3. Lightness, one of the most important factors in determining quality of Cynanchum wilfordii Hemsley, showed the highest in combination of diamond shape's steel blade and small pebble brasive at 61.90 in mechanical peeling. 4. As the speed of rotation gets faster, yields tend to lower in mechanical peeling. Peeling rates and lightness showed the highest at 66.8%, 57.96 respectively among treatments at 30 r.p.m. in mechanical peeling.