• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.307-314
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• 2013

Infrared optical systems are operated at low temperature and vacuum (LT-V) condition, whereas the assembly and alignment are performed at room temperature and non-vacuum (RT-NV) condition. The differences in temperature and pressure between assembly/alignment environments and operation environment change the physical characteristics of optical and opto-mechanical parts (e.g., thickness, height, length, curvature, and refractive index), and the resultant optical performance changes accordingly. In this study, using input relay optics (IO), among the components of the Immersion GRating INfrared Spectrograph (IGRINS) which is an infrared spectrograph, a simulation based on the physical information of this optical system and an actual experiment were performed; and optical performances in the RT-NV, RT-V, and LT-V environments were predicted with an accuracy of $0.014{\pm}0.007{\lambda}$ rms WFE, by developing an adaptive fitting line. The developed adaptive fitting line can quantitatively control assembly and alignment processes below ${\lambda}/70$ rms WFE. Therefore, it is expected that the subsequent processes of assembly, alignment, and performance analysis could not be repeated.

• Journal of Korean Medical classics
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• v.17 no.4
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• pp.155-170
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• 2004

The word "Sajeung(死證)" in "Huangjenaegyeong(黃帝內經)" includes a warning to lead to death if it is treated wrongly as well as a definite diagnosis saying that it is impossible to care diseases. A disorder condition of the body means that the balance of Eum-yang(陰陽) are broken or O-haeng(五行) doesn't have a good circulation. The prediction to progress is very important as much as decision of whether it is Sajeung or not because it can be changed by the time of day or night and also by changes of the seasons. In addition, according to the relations between Sangsaeng(相生) and Sanggeuk(相克) of O-haeng patients' diseases fall into a dangerous condition at the time under control. But sometimes it can be a severe illness even they are full of vigor. When living and dying has to be determined, it is emphasized the significance of inspection, auscultation and olfaction, inquiring and palpation(望聞問切法). Especially this is the key point to study people's face and pulse.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.139-148
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• 1998

Internal and external heat sources will cause to deform to machine elements in the contact joint of structure, which results in the change of contact pressure distribution different from initial assembly. Heat induced variations of contact pressure will change the static and dynamic properties such as contact stiffness, damping as well as contact heat conduction in the structure In order to design and control the intelligent machine tool operating in variant conditions more sophisticatedly, the good prediction for the changes of prescribed properties are strongly required especially in the contact elements adjacent to the rotational or linear bearing. This paper presents some computational and experimental results in regard to static and dynamic characteristics of the press-fitted bush and shaft assembly which is a model of the bearing innerrace and shaft assembly. In the condition of heat generation on the outer surface of the bush, the effects of changes in the negative clearance and the heat flux on pressure distribution and dynamic properties are investigated. Results of this study show that the edge effect of the bush and the initial clearance have effects on the transient dynamic characteristics significantly.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.571-581
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• 2015

Soil moisture content is generally accepted as an important factor to understand the process of crop growth and is the basis of earth system models for analysis and prediction of the crop condition. To continuously monitor soil moisture changes at kilometer scale, it is demanded to create high resolution data from the current, several tens of kilometers. In this paper we described a downscaling method for Advanced Microwave Scanning Radiometer 2 (AMSR2) Soil Moisture Content (SMC) from 10 km to 30 m resolution using a soil texture and field measurements that have a high correlation with the SMC. As a result, the soil moisture variations of both data (before and after downscaling) were identical, and the Root Mean Square Error (RMSE) of SMC exhibited the low values. Also, time series analyses showed that three kinds of SMC data (field measurement, original AMSR2, and downscaled AMSR2) had very similar temporal variations. Our method can be applied to downscaling of other soil variables and can contribute to monitoring small-scale changes of soil moisture by providing high resolution data.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.639-643
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• 2007

Tidal regime change with general hydrolic condition change is examined, according to Garolim Tidal Power Plant (TPP) operation. Numerical model has been developed for the Yellow and East China Seas region, in order to consider the tidal regime change by the TPP operation. The changes of tidal elevation and tidal current inside the Garolim bay are also investigated in details, along with examining the change of the tidal flat area with operation. The field measurement for the tide and current have been carried out for the validation of the numerical model and for understanding the state of current system in the present state.

• Journal of the Korean Society of Safety
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• v.5 no.2
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• pp.58-65
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• 1990

The purpose of this study is to consider the effects of strain rate on the stress-strain behavior of sheet metal at instability. The results and conclusions obtained as follows ： 1. As the strain rate increases, the fracture pressure increases and the polar height at fracture decreases. 2. The effect of strain rate on forming limit diagram produces a general lowering of the diagram with increasing strain rate but changes according to materials and strain paths. 3. The forming limit diagram predicted by swift instability theory is comparatively inconsistent with the experimental result at high strain rates, because there is inevitable gap between them.

• New & Renewable Energy
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• v.3 no.2 s.10
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• pp.3-10
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• 2007

Tidal regime change with general hydrolic condition change is examined, according to Garolim Tidal Power Plant (TPP) operation. Numerical model has been developed for the Yellow and East China Seas region, in order to consider the tidal regime change by the TPP operation. The changes of tidal elevation and tidal current inside the Garolim bay are also investigated in details, along with examining the change of the tidal flat area with operation. The field measurement for the tide and current have been carried out for the validation of the numerical model and for understanding the state of current system in the present state.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.29-36
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• 2003

Exhaust manifolds suffer from serious temperature variation during the thermal fatigue test. The spatial distribution of temperature changes at each moment. Because transient flow can not be simulated during the long period of temperature change, the simulation can not be performed by conjugate heat transfer analysis. In this study, a new procedure for transient thermal analysis is established by decoupling fluid-solid analysis. The procedure consists of (1) transient CFD calculation (2 cycles), (2) mapping heat transfer coefficient to the inner surface of solid mesh as a boundary condition of heat conduction analysis and (3) transient heat conduction analysis in the long period (30 min). The realistic temperature change can be predicted by this procedure.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.155-166
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• 1999

The construction of the coastal structures and reclamation work causes the circulation reduced in the semi-closed inner water area and the unbalanced sediment budget of beach results in an alteration of beach topography. Among the various fluid motions in the nearshore zone water particle motion due to wave and wave-induced currents are the most responsible for sediment movement. Therefore it is needed to predict the effect of the environmental change because of development and so the prediction of wave transformation dose. The purpose of this study is to introduce the relation between waves wave-induced currents and sediment movement. In this study we will show numerical method using energy conservation equation involving reflection diffraction and reflection and the surfzone energy dissipation term due to wave breaking is included in the basic equation. For the wave-induced current the momentum equation was combined with radiation stresses lateral mixing and friction Various information is required in the prediction of wave-induced current depending on the prediction tool. We can predict changes in wave-induced current from the distribution of wave especially near the wave breaking zone. To evaluate these quantities we have to know the local condition of waves mean sea level and so on. The results from the wave field and wave-induced current field deformation models are used as input data of the sediment transport and bottom change model. Numerical model were established by a finite difference method then were applied to the development plan of the eastern Pusan coastal zone Yeonhwa-ri and Daebyun fishing port. We represented the result with 2-D graphics and made comparison between before and after development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.99-108
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• 2020

In the field of aircraft icing prediction, surface roughness has been considered as critical factor because it enhances convective heat transfer and changes local collection efficiency. For this significance, experimental studies have been conducted to acquire the quantitative data of the formation process. Meanwhile, these experiments was conducted under low-speed condition due to the measurement difficulties. However, it has not been investigated that how the flow characteristic of low-speed will effects to the surface roughness. Therefore, the present study conducted experiment under low-speed icing condition, and analyzed the relation between surface roughness characteristics and icing condition. As an analysis method, the dominant parameters used in the previous high-speed experiments are employed, and roughness characteristics are compared. The size of roughness element was consistent with the previous known tendency, but not the smooth zone width.