• Korea-Australia Rheology Journal
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• 제17권3호
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• pp.99-110
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• 2005

This work presents results of finite element analysis of isothermal incompressible creeping viscoelastic flows with the tensor-logarithmic formulation of the Leonov model especially for the planar geometry with singular comers in the domain. In the case of 4:1 contraction flow, for all 5 meshes we have obtained solutions over the Deborah number of 100, even though there exists slight decrease of convergence limit as the mesh becomes finer. From this analysis, singular behavior of the comer vortex has been clearly seen and proper interpolation of variables in terms of the logarithmic transformation is demonstrated. Solutions of 4:1:4 contraction/expansion flow are also presented, where there exists 2 singular comers. 5 different types spatial resolutions are also employed, in which convergent solutions are obtained over the Deborah number of 10. Although the convergence limit is rather low in comparison with the result of the contraction flow, the results presented herein seem to be the only numerical outcome available for this flow type. As the flow rate increases, the upstream vortex increases, but the downstream vortex decreases in their size. In addition, peculiar deflection of the streamlines near the exit comer has been found. When the spatial resolution is fine enough and the Deborah number is high, small lip vortex just before the exit comer has been observed. It seems to occur due to abrupt expansion of the elastic liquid through the constriction exit that accompanies sudden relaxation of elastic deformation.

• 원예과학기술지
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• 제18권6호
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• pp.792-796
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• 2000

참외의 지주재배는 포복재배에 비하여 과실의 수량이 증가하였다. 지주재배는 수확전 낙과율이 47.6%로 무지주의 13.0%에 비하여 현저히 높았다. 그러나 개화 후 15 일에 aminoethoxyvinylglycine(AVG, $100mg{\cdot}L^{-1}$)을 엽면살포한 결과 낙과율이 10.9%까지 소하였다. AVG처리는 과실의 품질이나 숙기에는 영향이 없었다. AVG처리는 과설의 에틸렌 발생을 현저히 감소시켰다.

• The Journal of Korean Physical Therapy
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• 제8권1호
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• pp.1-14
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• 1996

The present case study has a object to investigate the changes in locomotion patterns of infant with athetoid cerebral palsy would be occured by the program when it is applied with upper extremity weight bearing. The subject has been limited to one infant over one year of age, selected from the patients in the physical therapy clinic, Rehabilitation Center, Taegu University. Subject is normal in the visual and auditory sense, but he is unable to walk on his own Subject weighted 2.9kg at birth and underwent severe postnatal kernicterus, always on the baby-walker at homo. He disliked supine position characteristic in moving in athetoid type before he was under the program. The program was applied 7 months. Each session of the program is composed of 7 stages : (1) prebriefing between the therapist and the parents (2) pretherapy amusement time of the infant (3) warming-up (4) upper extremity weight bearing (5) cooling-down (6) post-therapy amusement time (7) postbriefing. The locomotion of the subject is proved to be influenced by the program. He showed a leftward circular movement as a result of the exercise, reducing the involuntary movement of his head when he was positioned for crawling. Later he proceeded to develop into creeping, crawling, kneeling and finally cruising. In conclusion, it appeared evident that the locomotive abilities of the subject is improved by the program explored in this study. The higher locomotive patterns could be achieved such as crawling, sitting, kneeling and cruising wich enable the upper extremities weight bearing.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.204-208
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• 2004

Embedded business will be expanded market more and more since customers seek more wearable and ubiquitous systems. Cellular telephones, PDAs, notebooks and portable multimedia devices could bring higher microprocessor revenues and more rewarding improvements in performance and functions. Increasing battery capacity is still creeping along the roadmap. Until a small practical fuel cell becomes available, microprocessor developers must come up with power-reduction methods. According to MPR 2003, the instruction and data caches of ARM920T processor consume $44\%$ of total processor power. The rest of it is split into the power consumptions of the integer core, memory management units, bus interface unit and other essential CPU circuitry. And the relationships among CPU, peripherals and caches may change in the future. The processor working on higher operating frequency will exact larger cache RAM and consume more energy. In this paper, we propose advanced low power trace cache which caches traces of the dynamic instruction stream, and reduces cache access times. And we evaluate the performance of the trace cache and estimate the power of the trace cache, which is compared with conventional cache.

• Fibers and Polymers
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• 제3권4호
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• pp.159-168
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• 2002

Polyurethane foams were produced by using a homogenizer as a mixing equipment. Effects of stirring speed on the foam structure were investigated with SEM observations. Variation of the bubble size, density of the foam, compressive strength, and thermal conductivity were studied. A hybrid foam consisting of polyurethane foam and commercial polystyrene foam is produced. Mechanical and thermal properties of the hybrid foam were compared with those of pure polyurethane foam. Advancement of flow front during mold filling was observed by using a digital camcorder. Four types of mold geometry were used for mold filling experiments. Flow during mold filling was analyzed by using a two-dimensional control volume finite element method. Variation of foam density with respect to time was experimentally measured. Creeping flow, uniform density, uniform conversion, and uniform temperature were assumed for the numerical simulation. It was assumed for the numerical analysis that the cavity has thin planar geometry and the viscosity is constant. The theoretical predictions were compared with the experimental results and showed good agreement.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.154-160
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• 2009

본 논문은 친환경 절연재료인 Dry-Air 중 에폭시 수지의 연면절연특성을 구명하여 Dry-Air를 절연매체로 사용한 각종 절연설계 시에 응용 가능한 기초자료를 제공하고자 한다. 사용한 전극은 침 대 평판, 구 대 평판, KS M3015 전극으로써, 동일한 조건 하에서 전극의 종류에 따른 연면 절연 파괴 전압, 연면 거리, 연면방전 전계강도를 비교하였다. 연면전계강도는 침 대 평판 전극 하에서 가장 높게 나타났다. 또한 에폭시 수지의 두께와 지름을 변화시켰을 때의 연면 절연 특성은 에폭시 수지의 두께가 두꺼울수록, 지름이 길수록 연면 절연 파괴 전압이 높게 나타남을 확인하였다.

• 아시안잔디학회지
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• 제13권4호
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• pp.201-212
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• 1999

In use of pesticides in golf courses has been increased steadily. Environmental concern as well as decrease in efficiency led the turfgrass management into an alternate approach of using beneficial microorganism to deal with turfgrass pests. This study was focused on the use of such microorganisms for improving cultural environment and minimizing the use of pesticides. Microorganisms antagonistic to turfgrass diseases were applied to zoysiagrass fairways and creeping bentgrass greens in Yusung country club. Tharch accumulation, disease occurrence, and other cultural environments were compared among the combinations of microorganisms and suppliemental N applications. The application of microorganisms antagonistic to turfgrass diseases improved turf resiliency. Thatch thickness was 3.03cm in the control plot but it was 2.11cm in plots treated by microorganisms, indicating significant effects of microorganism application on reduction of thatch accumulation. Number of microorganism that can decompose of cellulose was higher at the plots treated with useful microbial products and it was considered that existence of higher population of microorganisms resulted in reduction of thatch accumulation. In the evaluation of relationship between thatch accumulation and disease occurrence, greater thatch accumulation was observed at the golf courses which have been frequently infested by large patch. However, the rate of thatch accumulation varied among surveyed golf courses regardless of the year of turf establishment. Therefore, management practice which can be effective for reduction of thatch could result in large patch suppression. The application of microorganisms on the established turfgrasses reduced the occurrence rate of pythium blight and yellow path diseases, whereas occurrence of brown patch and dollar spot increased.

• The Korean Journal of Ecology
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• 제21권5_2호
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• pp.519-529
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• 1998

The vegetation of alpine and subalpine zone from timber line, 2,000m altitude, to the upper area of Mt. Packtu were investigated by phytosociological method. The plant distribution along to the different altitudes shown as follows: Betula ermani community with Rhododendron redowskianum occupied dominantly at 2,000m area as patch forms, Rhododendron redowskianum community with Vaccinium uliginosum, at 2,180-2,200m area, both Vaccinium uliginosum and Rhododendron redowskianum community were compatible with each other at 2,243m area. Rhododendron redowskianum community at 2,250, Salix rotundifolia community, Erigeron thunbergii var. glabrata community, Dryas octopetala var. asiatica community and Carex atrata community were occurred frequently at 2,263m around Chonji Lake. Rhododendron aureum, Thunbergii coccinea and V accinium uliginosum showed higher cover degree than other species at 2,370m area, Phyllodoce coerulea-Rhododendron aureum community at 2,400m, Rhododendron redowskianum community at 2,470m, Rhododendron aureum community at 2,490m, Salix rotundifolia at 2,520m, Rhododendron redowskianum community at 2,580m, Dryas octopetala var. asiatica community, Salix rotundifolia, and bistorta achotensis etc. at 2,650 altitude area were settled as sparse, creeping shape on the surface soil and dwarf plants of about 15cm heights.

• 한국안전학회지
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• 제17권4호
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• pp.19-24
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• 2002

User-friendly-web-based database system for searching creep property data was developed. This system includes about 38000 creep data for 270 different materials including low carbon steel, stainless steel and alloy steel. Data on creep rupture, creep deformation, creep crack growth and creeping materials can be searched through this system. Retrieved data is displayed in numeric form and also presented in graphical form for visualizing the data. Furthermore, the creep rupture data is designed to be fitted to a regression equation of logarithmic stress using time-temperature parameter(TTP). The degree of the regression equation, orthogonal polynomials, was determined using analysis of variance.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.588-595
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• 2016

This paper is a study on head bolts that are used in A/C compressors to reduce production cost and solve leak problems on the head bolt seat area that causes massive intermittent malfunctioning during production. In this study, the pre-heat treated steel, which was used as a material in the head bolt, eliminated the heat treatment process after forging. The pre-heat treated steel head bolts, which have 10 % lower tensile strength than the conventional SCM 435 head bolts, were selected after considering the results of creeping rupture properties, axial force, and stress concentration per tensile strength variation. Then, the performance test and the durability test with the A/C compressor that was assembled with the pre-heat treated steel head bolts were performed and verified. Based on the results, the pre-heat treated steel head bolts developed in this study saved 7.3 % in production cost by eliminating the heat treatment process and the logistics process. Furthermore, the leak problem on the head bolt seat area in the A/C compressor was addressed significantly on the mass production assembly line.