• Journal of Adhesion and Interface
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• v.4 no.4
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• pp.7-14
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• 2003

"Tack" is defined as "the property that enables an adhesive to form a bond with the surface of another material upon brief contact under light pressure". The tack depends on a number of experimental parameters. We can control various experimental factors (contact force, dwell time, pretest speed) using probe tack tester. We are here concerned with pretest speed of experimental factors using SIS-based hotmelt PSA and water-borne acrylic PSA.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.112-118
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• 2011

The recycled asphalt concrete has gotten increasing attention due to the environmental issues. The volume of reclaimed asphalt has increased significantly for last few years because of city remodeling, pavement maintenance, utility excavation, and road widening. Considering the value of reclaimed asphalt, it is rather used for the recycled asphalt concrete than it is used for fill and cover up material instead of soil. This research will be a supplements incomplete issues from existing research results and suggests the quality control guideline for recycled asphalt concrete and upcoming laws. As the first step of research, the trial construction of RAP(Recycled Asphalt Pavement) performed in expressway construction sites. These trial construction sites have been checked every years. And another construction sites studied and selected for more deeper performance check of RAP. For this checks, we used automatic pavement survey equipment and computerized analysis tools. Also, DSR(Dynamic Shear Rheometer) was used for the fatigue life calculation of binder blends(RAP and virgin binder). As a consequence of this research, the application of recycled asphalt provides good enough quality for highway construction. The preceeding literatures reviewed shows that the asphalt rejuvenator are used in many countries but that type of chemical agent are not used in Korea. By using the data of trial construction and mix design in Chongwon-Sangju construction lane, the surface and base courses consisted with the 10% and 30% rap mix asphalt section maintains good performance for up to 7 years. Through the performance check and laboratory tests(DSR), the quality control and mixture's low temperature prevention are the important factor and chemical agent necessary for increasing the fatigue life of RAP binder.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.888-894
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• 2009

Recently, touch screen systems with direct touch interfaces are prevailing in digital products such as MP3's, DMB's, PDA's and navigators, which give rise to new interface issues related to speed, feedback and accuracy, and consider additional considerations for solving those issues in evaluation processes. Although paper prototyping method, the one of applicable methods, is efficient ways to evaluate the touch interface, it still requires a certain amount of adaptations for touch interfaces. This study aims to identify emerged issues regarding to paper-prototyping method for the evaluation of touch interface, to come up with alternatives for applying the method. The study started with analyzing the touch interface in digital products, and suggests the 'Touch Wheel' interface based on mainly used interface. 'Touch Wheel' interface allows the user searching for her/his favorite songs by rolling 'wheel-like' menu list. The Userbility test was conducted by 24 MP3 users with 4 times, and based on such conditions as materials, making methods and evaluating process of paper prototyping for evaluating the touch interface, effective alternatives were considered in each evaluation steps. As a result, paper prototypes for evaluating the touch interface should give active operations to subjects by offering direct experience, so as to provide subjects with proper feedbacks and for designers to collect effective alternatives for expected problems in initial interface design process.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.6
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• pp.96-105
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• 2010

This study identified the dynamic process of sandbar and vegetation distribution of the sandbar on the Tan-cheon River. The study area is located in the lower reaches of the Tan-cheon River that has been managed as an Ecosystem Reserve Area since 2002. For the study, the geomorphological process was analyzed through mapping analysis using a satellite image followed by analysis of the vegetation distribution through an on-site survey. The major findings were as follows : First, In the fluvial geomorphic process, various kinds of sandbars were developed in 1990s, the morphologic characteristics changing continuously. Second, In the distribution of vegetation on the sandbar, the sandbar shore was covered with bare sand substrate or intermittent annual vegetation because of the periodic fluctuation of the water-level due to intensive disturbances. Third, In the relationship between the sandbar formation and vegetation, four types of sandbars were classified: channel-shore stable bar, channel-shore unstable bar, mid-channel stable bar and mid-channel unstable bar, according to the fluvial disturbance & vegetation process. The study verifies that the vegetation distribution is reciprocally related to the geomorphological process. Accordingly, it is meaningful in the selection of plant species and the planting area of the sand bar. However, it is limited to the planting guidelines on river restoration projects. More diverse on-site experimental studies should be conducted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.579-584
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• 2017

The damper oil seal of a high-speed railway vehicle is made from nitrile butadiene rubber (NBR) in order to prevent lubricant from leaking into the damper and to stop harmful contaminants from entering the external environment while in service. Oil leakage through the seal primarily occurs from fatigue failure of the damper. Cumulative damage of the seal occurs due to the contact force between the rod and the rubber during movement due to track irregularities and cants, among other factors. Thus, the design of the oil seal should minimize the maximum principal strain at weak points. In this study, the optimal cross section of the damper oil seal was found using the multi-island genetic algorithm method to improve the durability of the damper. The optimal shape of the oil seal was derived using process automation and design optimization software. Nonlinear material properties for finite element analysis (FEA) of the rubber were determined by Marlow's model. The nonlinear FEA confirmed that the maximum principal strain at the oil leakage point was decreased 24% between the initial design and the optimum design.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.13-13
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• 2009

현재 열간단조 금형을 제작함에 있어 육성용접을 실시하는 방법이 금형강 STD61, STD11 등으로 제작하는 방법에 비해 보수나 비용적인 측면에서 이점을 가지고 있기 때문에 점차적으로 증가하고 있는 추세이다. 열간단조 공정에서 금형은 $1000^{\circ}C$이상의 고온재료와 반복접촉하게 된다. 이때 이형제의 사용은 급속냉각 및 급속가열의 열피로를 가속시킨다. 또한, 금형은 반복충격에 의한 기계적 피로를 받게 된다. 이러한 금형의 사용환경을 고려한 FCW는 종래 고가의 $2.8{\sim}3.2{\Phi}$인 외국산 FCW를 사용하였으나 이를 대체한 $3.2{\Phi}$ 태경 FCW가 국내에서 개발되었다. 하지만 개발된 FCW를 사용하여 제작된 금형의 수명이 부족한 현상이 발생하였다. 이에 금형의 수명을 연장시킬 수 있는 내균열성 및 내열충격성을 확보한 태경 FCW의 개발과 개발된 FCW의 성능평가가 요구되었다. 특히 열간단조 금형에 있어서 중요한 내열충격성의 경우 가열과 냉각의 반복 Cycle에 의한 Thermal shock의 평가가 대부분이며 높은 Cycle로 인해 많은 시간이 걸리며, 또한 가열과 냉각을 오갈 수 있는 고가의 시험장치가 요구된다. 그러므로 개발된 FCW 육성용접부의 내균열성 및 내열충격성을 평가할 수 있는 방법에 대한 연구와 특히 내열충격성을 시간이 적게 걸리면서도 경제적으로 평가할 수 있는 방법에 대한 연구가 필요하다. 본 연구의 목적은 열간단조 금형 육성용접부의 내균열성 및 열충격특성을 평가할 수 있는 방법에 대한 검토와 특히 내열충격성에 대해 J.W.Kim등의 시험방법을 참고하여 시간이 적게 걸리면서 저 비용으로 열 충격특성을 평가할 수 있는 시험법을 고안하는 것이다. 이를 위한 방법으로 육성용접부의 내균열성을 평가하기 위한 상온 Bending을 실시하였고, 내열충격성을 평가하기 위한 염욕로를 이용하는 고온 Bending을 고안하여 실시하였다. 상온 Bending, 고온 Bending 모두 3점 굽힘시험을 적용하였다. 고온 Bending의 가열방법으로는 염욕로를 사용하여 시편이 대기중에서 약 $850^{\circ}C$의 온도가 될 수 있도록 하였다. 시편은 각각 열처리를 하여 요구 경도를 확보하였고, 이를 염욕로에서 5분간 가열 및 유지하여 취출 후 굽힘하중을 가하여 변위의 정도로 열충격을 평가하는 방법을 사용하였다. 상온 Bending은 극한변형량과 파단부 극한응력으로, 고온 Bending은 고온 극한변형량으로 평가를 하였고, 외국산 FCW를 사용한 육성용접부를 비교대상으로 하였다. 평가 결과 개발된 국산 $3.2{\Phi}$ 태경 FCW의 성능은 외국산 FCW와 유사하거나 우수한 것으로 평가되었고, 실제 금형을 제작하여 현장에 적용한 결과 금형의 수명이 연장된 것이 나타났다.

• Journal of Sericultural and Entomological Science
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• v.34 no.1
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• pp.1-7
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• 1992

For a long-term preservation of silkworm stocks by frozen gonad storage, fundamental topics such as freezing rate and transplanting stage of the gonad, proper cryoprotectant, and super-cooling temperature and freezing point of the freezing medium were examined and following results were obtained. Proper method to anesthetize the ovary-recipient silkworm was to dip the animal to cold water for 10 minutes, and the ovary taken from the 4th instar larvae was more suitable for freezing-preservation than that from the 5th. Concerning the cryoprotectant, glycerol and DMSO were effective to prevent cryoinjury of the ovary, but sorbitol was not. The supercooling temperature and freezing point of the medium to freeze the ovary and testes were checked, and consulting with the results desirable cooling rate was confirmed. On the desirable conditions of transplanting methods, freezing rate and cryoprotectant concentration ect., the next generation was obtained when the females implanted frozen-thawed ovaries mated with normal males, but none of the normal females mated with the males implanted frozen-thawed testes laid fertilized eggs. Now it is needed to improve the connecting ration of the ducts associated with the transplanted testis to those of the hosts.

• Korean Journal of Environmental Agriculture
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• v.5 no.2
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• pp.106-112
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• 1986

Biochemical and histological effects of ozone gas (0.3 ppm) on rice plant were discussed. After ozone expoure, damage symptom, percentages of destroyed leaves, activities of peroxidase and polyphenoloxidase, and the contents of flavonoid, protein and sugar were examined on two rice varieties (Seokwangbyeo, Jinjubyeo), on tillering stage, and at different exposure time (0, 1, 3, 5 hr). The result were as followed. 1. The ozone-injured cell adjoining stomata become pigmented red-brown. 2. The percentage of injured leaves in Jinjubyeo was higher than that in Seokwangbyeo. 3. The activities of peroxidase and polyphenoloxidase increased on ozone-injured leaves. 4. The peroxidase activity increased with time in Jinjubyeo compared to Seokwangbyeo. 5. Peroxidase isozyme spectrum was altered after ozone exposure. 6. The content of flavonoid and reducing sugar in the rice leaves was increased, but the contents of protein was reduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.346-354
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• 2018

In the probe of a medical ultrasound device, three parts were selected randomly by the examiner and the bacteria in the probe were detected by the blood examiners. In addition, the degree of death of the pathogenic bacteria after each disinfection of the detected pathogens, disinfecting ethanol, and disinfecting tissue of the detected pathogens were analyzed quantitatively. The following was detected: S Aureus (32.3 %), Bacillus spp. (26.5 %), Micrococcus spp. (21.5 %), and CNS (20 %). With the conventional probe, S. aureus (26.2 %), a playback curve (24.2 %), and a micron (19.5 %), Micrococcus spp. (15.5 %), and CNS (14.6 %) were observed. In the fan probe, S. aureus (24.7 %), Enterococcus (24.7 %), Enterococcus (17.7 %), and CNS (13.8 %) were detected. The disinfection of the three pathogens detected revealed sterilization of most of the pathogens, and most cases contained at least 91.3 % of the total sterilizing effect (P>0.05). In addition, for the disinfection of Propolis extract and disinfecting tissue, the disinfection effect was lower than that of disinfecting ethanol, but the difference was not statistically significant (P>0.05). The results revealed bacteria on most of the ultrasound probes. Antiseptic disinfection of surgical instruments using an extract of propolis works with results similar to those of ethanol. A blood test along with disinfection can help prevent infection if an ultrasound probe is applied to food.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.1
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• pp.50-57
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• 2020

The loss of posterior support and the abnormal jaw relation can cause pathologic findings. If deep bite patients with multiple missing teeth, can not have the stable posterior contact, the mandible moves posteriorly, and consequently the overjet and overbite get worse. And when the mandibular irregular occlusal plane is corrected, it is easier to have the bilateral balanced occlusion with the maxilla. So the treatment goal is to give proper posetrior support and establish appropriate anterior guidance, and ultimately provide improved mastication and esthetics recovery. In this case, a 68 year old man, having deep bite without posterior support was evaluated by the vertical dimesion decision flow-chart. An available prosthetic height, anterior occlusal relation such as overjet, overbite and the esthetic part such as facial height and the cephalometric analysis are the factors to be considered.