• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.73-80
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• 2005

In general, the performance of movable nozzle used for thrust vector control in solid rocket motor is estimated on the basis of the effective pivot of nozzle. However, it is nearly impossible to define the exact effective pivot by the mathematical model or experimental technique owing to pivot dynamics. In this paper, pivot dynamic properties were investigated by ADAMS simulation technique and trajectory of the exact effective pivot was modelled by the artificial neural network. Comparison of the proposed method was made with the virtual movable nozzle (computer simulation) to verify the method, and showed good agreement. Therefore, the proposed method will be applicable to predict the effective pivot of movable nozzle during bench or ground test.

• The Journal of the Acoustical Society of Korea
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• v.19 no.5
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• pp.41-45
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• 2000

The effective elastic constants of a single-crystal superlattice film have been determined by two methods based on the velocities of surface acoustic waves (SAW). One method uses formulas to calculate the effective elastic constants of a superlattice from the known elastic constants of the constituent layers. The calculated effective elastic constants are tested by comparing the corresponding SAW velocities calculated for thin-film/substrate systems with the corresponding SAW velocities measured by line-focus acoustic microscopy (LFAM). The other method determines the effective elastic constants of the superlattices by inverting the SAW velocity dispersion data measured by LFAM. The results of both methods applied to a TiN/NbN superlattice film are in good agreement.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.56-60
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• 2002

Since the transmittance of solar radiation directly affected by the structural frames of greenhouse can be changed according to the ratio of diffuse to direct radiations, it is necessary to investigate the transmittance of greenhouse at the different weather conditions. We can easily get the data of total solar radiation from the Meteorological Administration, but we have to personally measure the photosynthetic photon flux (PPF). If the relationship between total solar radiation and PPF is established, the PPF can be simply acquired from the relationship. Sol it is required to develop the equation to calculate PPF depending on weather condition. This study was conducted to determine the transmittance of PPF at canopy level in glasshouse and the correlation between total solar radiation and PPF at clear and cloudy days. The variation phase of greenhouse transmittance at clear day was very different from that at cloudy day. It was concluded that the proper transmittance, depending on the weather condition, should be adopted to calculate the accurate total solar radiation and PPF in greenhouse. The transmittance of solar radiation was the same as that of PPF in greenhouse. It was confirmed that the ratio of PPF to total radiation increased as the amount of cloud increased. The correlation between the hourly total solar radiation and PPF was derived.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.282-288
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• 1985

This experiment was conducted to investigate the changing patterns of the available elements by the control of lime addition amount and temperature in Acid Sulfate Soils under the submerged condition. The results obtained were summarized as follows: 1. pH and contents of available phosphate, soluble silicate, $NH_4-N$, and exchangeable iron in soils were decreased but exchangeable aluminium and manganese, and water soluble sulfur in soils increased after submergence. 2. Lime treatment increased pH, available phosphate, soluble silicate, $NH_4-N$, and water soluble sulfur, but that decreased exchangeable aluminium, iron, and manganese in soils. 3. Treatment with 12me/100gr of Ca as $CaCO_3$, showed the marked effect in increasing the exchangeable aluminium and iron, and increasing pH value to about 6.5 as well as available phosphate and $NH_4-N$. 4. Increases in available phosphate, $NH_4-N$, and exchangeable iron with aging of the soil flooded and lime treated were higher at $35^{\circ}C$ than those at $25^{\circ}C$. 5. Throughout submerged period a significant positive correlation was observed between pH and soluble silicate while the pH has negative correlation with exchangeable elements such as aluminium, iron, and manganese etc.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1377-1380
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• 2010

본 연구에서는 해양준설퇴적물의 유효활용을 위한 역학적, 환경적 실험을 통한 건설재료로서의 활용성을 검토하였다. 울산 방어진과 진해 행안만에서 수거한 준설토로 고화처리토 및 경량혼합토 공시체를 제작하여 압축특성 및 응력-변형 거동 등 공학적 실험을 실시하였다. 해양오염토 유효활용을 위한 활용방법도 예시하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.137-138
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• 2012

광원의 광달거리 산출에 이용되는 유효광도의 계산은 국제항로표지기술협회 권고에 의해 기존에 크게 3가지의 형태가 이용되었다. Schmidt-Clausen 식, Allard 식, Blondel-Rey-Douglas 식이 그것이다. 그러나 이 식들이 가지고 있는 한계로 인하여, 새로운 계산식이 요구되었으며, 2008년 12월 IALA 권고서 E-200시리즈에서 새롭게 Modified-Allard 식이 발표되었다. 본 논문은 새롭게 발표된 Modified-Allard 식에 따라 실제로 현장에서 이용되고 있는 등명기의 유효광도를 산정해 보았다.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.964-968
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• 2010

본 논문에서는 다양한 협동조합들 중 대표적인 협동조합이라고 할 수 있는 농업협동조합을 대상으로 협동조합의 특수성에 맞는 리더십을 모색하며 리더십이 조직유효성 및 조직 몰입도에 미치는 영향을 연구할 수 있는 모형 및 분석의 제언을 하고자 한다. 변혁적 리더십과 조직유효성의 측정은 농업협동조합으로 보고자 하였으며, 이를 통하여 조합장의 리더십이 조직유효성과의 상관관계를 분석할 수 있을 것이다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.1
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• pp.159-184
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• 1997

인체에 안전하고 유효한 화장품을 개발하고 제품의 질을 평가하기 위하여 표준화된 안전성 및 유효성 시험방법이 필요하며, 기능성 화장품 등 제품의 개발 환경에 맞추어 신규 시험방법의 개발이 요구되고 있다. 또한 유럽에서부터 시작되고 있는 화장품 영역에서의 동물실험을 줄이려는 경향에 따라 동물대체 실험 법도 동시에 요구되고 있는 실정이다. 이에 일반 화장품 및 기능성 제품 개발에 필요한 피부에서의 안전성 및 유효성 시험 법에 대한 현황과 표준화의 필요성에 대한 제안과 새로운 시험법의 개발 전망에 대하여 알아보고, 동물 대체 실험 법에 대한 연구 동향과 전망에 관해 기술하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.10-11
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• 2000

광섬유 격자는 WDM 광시스템의 필터뿐만 아니라 센서로도 많은 연구가 되고 있다. 이 경우 필수적인 것이 유효굴절률에 대한 해석이다. 유효굴절률은 광섬유의 코어와 클래딩의 굴절률과 반지름에 따른 수치해석을 통해서도 구할 수 있다. 수치해석과정에서 필수적인 것이 파장에 따른 굴절률을 계산할 수 있는 Sellmeier식이다$^{(1)}$ . 본 연구에서는 광섬유격자 쌍을 이용하여 광섬유의 유효굴절률을 클래딩 모드수에 따라 측정할 수 있는 새로운 방법을 제시한다. (중략)

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.213-219
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• 2008

The purpose of this study is to propose frame analysis method for flat plate slabs having edge beam under lateral loads. Flat plate system is defined as the system only with slab of uniform thickness and column. However, the slab system generally incorporate edge beams at exterior connection in actual design. ACI 318 (2005) allows three methods for conducting flat plate system analysis subjected to lateral loads. There are the finite element method (FEM), the equivalent frame method (EFM), and the effective beam width method (EBWM). Among methods, the EBWM enables us to analyze practically by substituting the actual slab to beam element. In this model, the beam element has a thickness equal to that of the slab, and effective beam width equal to some fraction of the slab transverse width. However, the established EBWM was generally proposed for variables of geometry or stiffness reduction factor and seldom proposed for the effect of edge beams. This study verifies that, in the case of flat plate system having edge beams at exterior connections, the lateral stiffness is considerably larger than without edge beams. Therefore it need to analysis method for considered the effect of edge beams. In this study, an analysis model is proposed for the flat plate system having edge beams under lateral loads by considering the effect of edge beams. To verify the accuracy of proposed model, this study compared results of the proposed EBWM with results of FEM of flat plate systems having edge beams under lateral loads. Also, the proposed approach is compared with experimental results of former research.