• The Korean Journal of Pesticide Science
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• v.8 no.2
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• pp.103-106
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• 2004

To confirm physico-chemical stability of formulated products, this study was conducted under different storage conditions; room temperature and accelerated temperature of $54^{\circ}C$. The tested pesticide formulations were dichlorvos 50% EC, acephate 50% WP, hymexazol 4% DP, thiram 80% WP and isoprothiolane 12% GR. The selected formulations were stored for 10 weeks and 5 years under the given temperature in maximum and contents of active ingredients were also analyzed by GLC or HPLC after each time of storage. The degradation rates of 5 active ingredients under the two conditions showed a similar trend except acephate. Acephate was rapidly decomposed at $54^{\circ}C$ but slowly decomposed at room temperature, and the degradation rate under the accelerated condition was 2.4 to 5-fold higher than that under the room temperature. Consequently, the stability test on active ingredients in pesticide formulations was able to recommend to be carried out under the accelerated condition except acephate. And the physical properties of all formulations tested under two storage conditions were good.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.303-309
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• 2007

For the propagation of elastic waves in unbounded domains, absorbing boundary conditions at the fictitious numerical boundaries have been proposed. In this paper we focus on both first and second order paraxial boundary conditions(PBCs) in the framework of variational approximations which are based on paraxial approximations of the scalar and elastic wave equations. We propose a penalty function method for the treatment of PBCs and apply these into finite element analysis. The numerical verification of the efficiency is carried out through comparing PBCs with Lysmer-Kuhlemeyer's boundary conditions.

• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.119-123
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• 2000

Effect of fluctuating temperatures on the development of the immature beet armyworm, Spodoptera exigua (H bner), was analyzed. At constant rearing temperature regimes, the estimated developmental threshold temperatures were varied among stages and instars, but had an average 13$^{\circ}C$ from egg hatch to adult emergence. Based on the 13$^{\circ}C$ threshold temperature, we set up three different rearing temperature regimes having the same day-degrees. Two fluctuating temperature regimes changed significantly the developmenta1 period expected by the constant rearing temperature regime. Under the same thermophase temperature (25$^{\circ}C$), the thermocycling regime with the higher cryophase temperature (10$^{\circ}C$) decelerated the developmental rate probably by lowering temperature limit thor development, but that with the lower cryophase temperature (5$^{\circ}C$) gave a negative developmental effect.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.102-109
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• 2015

The methodology to calculate loads on the bearings of the gas-turbine engine is presented for design of high-speed bearing. Firstly, the loads on the bearings are formulated according to the force and moment equilibrium with gyroscopic moment in three-dimensional space. Afterward, operating loading conditions of the engine are presented by applying the Joint Service Specification Guide, and magnitudes of transient and steady bearing loads are estimated based on the operating conditions. The calculated loading conditions of the bearings will be used for the essential design boundaries for the detail structural design and rig test.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.103-109
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• 2003

A numerical analysis of cable-stayed bridge is conducted to determine optimum longitudinal modulus of elasticity which represents the boundary condition between the tower and main girder. The effect of longitudinal modulus of elasticity is investigated for different loading condition (live load, wind load, seismic load), respectively. There are significant changes in the member forces as variations of longitudinal modulus of elasticity, such as, $k_h$=e=100tonf/m/bearing (live load), $k_h$=e=1000tonf/m/bearing (seismic load), However, the wind loads do not affect member forces. The optimum longitudinal modulus of elasticity is determined from considering minimum member forces in the numerical analysis results.

• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.177-185
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• 2005

Construction uncertainties are frequently exposed to the claims. In most cases, an interpretation of the claims is based on the construction contract. Therefore, the key points of contract negotiation are how to fairly distribute the contract risks to the client and contractor. For these, a FIDIC that is considered as an international standard contract form would be a good reference to decide reasonable contract risk distribution. In order to find out any unreasonable and unfair contract clauses at the general conditions of contract applying generally to public construction project in Korea, this study surveys, analyses and evaluates the general conditions of contract based on a FIDIC, and then proposes a risk mitigation methodology to response those clauses' risk factors reasonably.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.849-852
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• 2008

In the wheel tracking test to evaluate abrasion resistance for concrete surface coating materials applied parking lot, weight of the wheel, test temperature, scattered sand amount, wheel speed, etc. various test condition is used for reliable evaluating the abrasion resistance performance of surface coating materials and the results depends on the test condition. In this paper, we carried experimental study as following on abrasion resistance with 2kinds of different environmental conditions. - Commons : real car tire with 300kg of load, 5km/h of speed, 80,000 cycle. - Control A : no other deterioration condition - Control B : scattering 1.0g of sand per every 30rounds from 1m height.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.203-209
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• 2018

To correctly predict the neutron behavior based on diffusion calculations, it is necessary to adopt well-specified boundary conditions using suitable diffusion approximations to transport boundary conditions. Boundary conditions such as the zero net-current, the Marshak, the Mark, the zero scalar flux, and the Albedo condition have been used extensively in diffusion theory to approximate the reflective and vacuum conditions in transport theory. In this paper, we derive and analyze these conditions to prove their mathematical validity and to understand their physical implications, as well as their relationships with one another. To show the validity of these diffusion boundary conditions, we solve a sample problem. The results show that solutions of the diffusion equation with these well-formulated boundary conditions are very close to the solution of the transport equation with transport boundary conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.210-210
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• 2021

Delft Dashboard는 유동모델을 위한 오픈소스 프로그램으로 로컬 및 글로벌 데이터 세트를 사용하여 다수의 입력 매개변수를 신속하게 생성, 편집하고 모델 내 입력을 시각화하도록 설계된 그래픽 사용자 인터페이스(GUI) 이다. 특히 Delft Dashboard에 제공하는 개방경계조건을 이용하면 격자영역을 인식하여 개방경계를 자동으로 분배 및 지정하고, 각 개방경계 위치에서 분조별 조석조화상수 값도 산출되므로 유동 모델의 편의성을 증대시킬 수 있지만 상황에 따라 적합하게 경계를 분배하여 개방경계로 지정하는 것이 중요하다. 본 연구에서는 Delft Dashboard에서 제공하는 개방경계조건 중 TPXO 8.0을 이용한 Delft-3D 해수유동 수치모의를 수행하여 개방경계조건이 결과에 미치는 영향을 분석하였다. TPXO 8.0의 경우 격자영역에서 개방경계조건을 설정할 때 사용자가 경계조건에 포함될 격자 수를 지정하면 전체 격자경계에서 격자 수에 해당하는 만큼 경계를 나누어 개방경계를 지정하고 각 개방경계 위치에서의 분조별 조석조화상수값을 산출한다. 특히 격자 수에 따라 개방경계로 지정되는 정도에 따른 영향을 분석하기 위하여 인위적으로 경계를 다양하게 분배하여 개방경계를 지정한 후 수치모의에 적용하였다. 수치모의는 동해안 고리원전 인근을 대상으로 격자 생성 후 Delft Dashboard TPXO 8.0을 이용하여 전술된대로 다양한 개방경계조건을 생성하였고 이를 Delft-3D내 적용하여 해수유동 모의를 수행하였다. 각 개방경계 조건별 초기 수면 변위 분석 및 인근 조위관측소의 관측값의 비교를 통해 개방경계조건이 모의결과에 미치는 영향을 분석하였다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.93-93
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• 2011

스포츠웨어 바람막이용도에 사용되는 대부분의 소재는 폴리아미드계 소재이며, 국내에서는 대부분 나일론6 소재를 사용하고 있다. 최근 소비자들의 요구는 점점 경량화되고 있고 야외활동 증가와 더불어 착용감이 우수한 소재를 요구하고 있다. 이러한 시즘에 국내에서 많이 사용되는 나일론6 소재를 이용하여 직물단계에서 경량감과 스트레치성이 발현될수 있는 나일론6 경량 Mechanical 스트레치 직물 개발에 대한 연구를 진행하고자 함이다. 본 연구에서는 직물단계에서 경량감과 스트레치성이 발현될수 있는 나일론6 경량 Mechanical 직물개발을 위해 공중합 나일론6 폴리머와 일반 나일론6 폴리머를 복합방사설비를 이용하여 SIDE BY SIDE POY 26d/6f 원사를 제조한 후, Nip Belt 가연설비로 연신비, 가연 1st 히터온도, 벨트각도 조건에 따라서 제조된 4가지의 나일론6 가연사 DTY 20d/6f와 T사에서 생산되고 있는 나일론6 가연사 DTY 20d/7f를 동일한 직물설계 조건에서 위사방향으로 제직을 실시하였다. 직물설계 조건은 경사를 나일론 DTY 20d/7f, 경사밀도는 2가지, 위사밀도 2가지으로 설계하여 제직하였으며, 이렇게 제조된 직물(생지)를 일반 나일론6 염색가공 공정조건으로 전처리, 염색, 가공, 코팅 공정을 거친후, 신축성 평가를 실시하였다. 동일한 제직조건 및 염색가공 조건에서 제조된 직물의 신축성은 가연조건인 가연 연신비가 높고, 가연 1st 히터온도가 높은 조건에서 높게 나타남을 알 수 있었다. 경사밀도가 낮은 조건이 수축이 많이 진행됨을 알 수 있었으며, 가연조건인 가연 연신비가 높고, 가연 1st 히터온도가 높은 조건에서 수축이 더 많이 이루어짐을 알 수 있었다. 권축률이 높은 가연사 조건이 그만큼 수축이 많이 들어옴을 나타내는 결과로 사료되며, 위사밀도가 낮은 조건이 수축이 좀 더 많이 진행됨을 알 수 있었으며, 위사밀도가 너무 많으면 가연사끼리 상호 수축할 수 있는 정도를 감소시키는 결과로 판단된다. 전처리, 염색가공, 코팅이 완료된 최종 원단의 신축성 평가를 실시한 결과, 비교사로 제직된 최종 원단은 8~10%수준, 가연사 제조조건에 따른 제조된 4가지의 가연사의 신축성은 12~18%의 신축성을 보임을 알수 있었다. 향후, 제직설계 및 염색가공 조건의 다양화로 연구를 진행할 계획이다.