• 한국식품과학회지
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• 제31권3호
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• pp.682-687
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• 1999

식품동결에 의한 품질손상에 있어 크게 영향을 미치는 인자중의 하나가 체적변화에 의한 조직 파괴이므로 본 연구에서는 압력변환기를 사용하여 식육의 동결, 냉동냉장 및 해동시에 일어나는 내부압력을 조사하였다. 그 결과, 우육은 $-20^{\circ}C$에서 밀도는 $942.17\;kg/cm^2$으로, 체적은 6.33% 증가하였으며, 급속 및 완만동결시 우육의 내부압력 변화 경향은 동결 직전에 급격히 상승한 후 동결 초기부터 최대빙결정생성대를 통과하는 동안은 급격히 감소하다가 다시 온도가 내려감에 따라 압력변화는 증가와 감소를 반복하여 상승하는 경향을 보여 주었고, 동결시의 내부압력 크기는 약 $8{\sim}10\;psig$ 수준이며, 내부압력의 변화 경향은 정지공기식보다 침지식에서 약 1 psig 정도 크게 나타났다. 냉동냉장시에 일어나는 내부압력의 상하변화는 돈육의 품온차가 ${\pm}1^{\circ}C$일 때, 시료중량에 마라 $1.84{\sim}2.32\;psig$ 정도의 내부압력 차가 반복적으로 발생됨을 알 수 있었다. 또한, 돈육의 해동시 내부압력은 해동 개시 후 급격히 상승하여 5분 이내에 최고압력에 도달한 이후에는 서서히 하강하였으며, 해동시에 발생한 내부압력의 값은 동결시의 내부압력 값보다도 대부분 크게 나타났다. 또한, 균온처리한 우육의 동결시 내부 압력 값은 약 $1{\sim}4\;psig$ 수준으로 균온처리하지 않은 우육에 비하여 매우 적게 나타났으며, 동결소요시간도 약 $10{\sim}20%$ 정도 짧게 나타났다.

• 지역사회간호학회지
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• 제15권3호
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• pp.353-364
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• 2004

Purpose: The purpose of this study was to investigate the types and frequencies of nursing intervention of home health care in Public Health Centers and its effects. Method: The data collection period for this study lasted from March 1 to December 31, 2003. The clients were sampled by a stratified randomized method among those who had been cared for at least 3 months. The data was analyzed by SPSS for description. ANOVA, paired t test, etc. Result: The types and frequencies of nursing intervention in major chronic health problems were significantly different. The main types of nursing intervention in hypertension and DM patients included education on disease management, regular exercise, stress management, diets, etc. CVA patients were intervened in pain control (ice or hot pack, massage), position changes, and ROM exercise. Cancer patients received imaginary or relaxation therapy, pain control (ice or hot pack, massage), hospice, etc. After the intervention, the drug compliance of hypertension (8.2 days per month) and DM patients (6.2 days per month) improved. Blood sugar levels (FBS 7.6, post partum 2hrs $21.4(mg/d{\ell})$ and blood pressure(systolic 9.8, diastolic 4.3 mmHg) lowered significantly. All aspects of QOL also improved (total 3.68). Conclusion: The types and frequencies of nursing intervention were determined by characteristics of the health problems, and home health care nursing intervention in Public Health Centers was effective to the elderly of the community in many aspects.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1181-1181
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• 2001

Robinson with ${coworkers}^{1}$ have introduced two-state outer-neighbor bonding model to explain the anomalies of water. The studies on the properties of water as a function of temperature and pressure revealed that, unlike other ideas, all $H_2O$ molecules in liquid are tetrabonded. On the average they are forming two different bonding types. One type is the regular tetrahedral water-water bonding similar to that found in the ordinary ice Ih, whereas the other is a more dense nonregular tetrahedral bonding similar to that appearing in the ice II. The transformation between these two bonding forms is evidenced by FT-NIR experiment. The FT-NIR measurements were done for liquid water in the temperature range from $20^{\circ}C$ up to $80^{\circ}C$ in a wide extent of frequencies: 12 000 - 4000 $cm^{-1}$ /. Temperature dependent variations in the volume fraction of these two structures are directly related to the spectral changes. The absorbance variations are explored by means of the two-dimensional correlation spectroscopy (2DCOS), principal component analysis (PCA), curve fitting and second derivatives. The presence of the isosbestic points in a range of the combination and overtone transitions indicates that the experimental spectra are a superposition of two temperature independent components. One component of diminishing intensity with temperature increase, is assigned to a stronger hydrogen bonds occurred in the Ih type, whereas the second component showing an opposite behavior, one can attribute to a weaker H-bonds characteristic for the II type. The understanding of the hydrogen bonding network in the liquid water is very important in interpretation of the interaction between water and protein chain. The two-state model of water surrounding the protein surface could advance an understanding of the hydration process.

• Structural Engineering and Mechanics
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• 제75권4호
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• pp.487-496
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• 2020

Most of the previous works on numerical analysis of galloping of transmission lines are generally based on the quasisteady theory. However, some wind tunnel tests of the rectangular section or hangers of suspension bridges have shown that the galloping phenomenon has a strong unsteady characteristic and the test results are quite different from the quasi-steady calculation results. Therefore, it is necessary to check the applicability of the quasi-static theory in galloping analysis of the ice-covered transmission line. Although some limited unsteady simulation researches have been conducted on the variation of parameters such as aerodynamic damping, aerodynamic coefficients with wind speed or wind attack angle, there is a need to investigate the numerical simulation of unsteady galloping of two-dimensional iced transmission line with comparison to wind tunnel test results. In this paper, it is proposed to conduct a two dimensional (2-D) unsteady numerical analysis of ice-covered transmission line galloping. First, wind tunnel tests of a typical crescent-shapes iced conductor are conducted firstly to check the subsequent quasisteady and unsteady numerical analysis results. Then, a numerical simulation model consistent with the aeroelastic model in the wind tunnel test is established. The weak coupling methodology is used to consider the fluid-structure interaction in investigating a two-dimension numerical simulation of unsteady galloping of the iced conductor. First, the flow field is simulated to obtain the pressure and velocity distribution of the flow field. The fluid action on the iced conduct at the coupling interface is treated as an external load to the conductor. Then, the movement of the conduct is analyzed separately. The software ANSYS FLUENT is employed and redeveloped to numerically analyze the model responses based on fluid-structure interaction theory. The numerical simulation results of unsteady galloping of the iced conduct are compared with the measured responses of wind tunnel tests and the numerical results by the conventional quasi-steady theory, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.609-614
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• 2005

Gas hydrates are ice-l ike sol id compounds that are composed of water and natural gas. All common gas hydrates belong to the three crystal structures that are composed of five polyhedral cavities formed by hydrogen bonded water molecules and stable in specific high pressure and low temperature conditions. Gas hydrates contain large amounts of organic carbon and widely occur in deep oceans and permafrost regions, and they may therefore represent a potential energy resource in the future. United States and Japan perform the national R&D programs for the commercial production of gas hydrates in 2010's. The study on gas hydrates are also important for exploration and development of natural gas in the regions where gas hydrates are accumulated and could be formed. Although their global abundance is debated, they play an important role in global climate change since methane is a 50 times more effect ive greenhouse gas than carbon dioxide. Natural gas hydrates also form a possible natural hazard if rapidly dissociated and can cause slides and slumps and in the marine environment associated tsunamis.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.1023-1026
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• 2006

As it was shown recently, climate changes in Antarctica resulted in interannual trends of some climatic parameters like sea level pressure, surface air temperature, ice thickness and others. These tendencies have effect on the Southern Ocean meteorological and hydrological regime. The following remote sensing data: AVHRR MCSST data, satellite altimetry data (merged data of mission ERS-2, TOPEX/Poseidon, Jason-1, ENVISAT, GFO-1) are used to analyse the interannual and/or climatic tendency of sea surface temperature (SST) and sea level anomaly (SLA). According to the obtained results, SST has negative trend $-0.02{\pm}0.003^{\circ}C/yr$ for 24-yr record (1982-2005) and SLA has positive trend $0.01{\pm}0.005$ cm/yr for 24-yr record (1982-2005) and $0.24{\pm}0.026$ cm/yr for 12-yr record (1993-2005). However in some areas (for example, Pacific-Antarctic Ridge) SST and SLA tendencies are stronger $-0.065{\pm}0.007^{\circ}C/yr$ and $-0.21{\pm}0.05$ cm/yr, respectively.

• 한국초전도ㆍ저온공학회논문지
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• 제4권1호
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• pp.1-3
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• 2002

Single Josephson junctions, which are of cross type, of $50 ${\mu}{\textrm}{m}$ {\times} 50 ${\mu}{\textrm}{m}$$ were fabricated under several oxidation conditions to Investigate controllabilities of critical current density (Jc) with the standard KRISS processes. Considering that the self-field effect suppresses the observed critical current (Ice) at high Jc region, we could reasonably estimate Jc values from I-V observations. The dependence of the obtained Jc as a function of exposure, which is equal to pressure (P) times time (t), was well fitted to a curve of Jc ~ (Pt)-0.34. The maximum Jc value at the controllability margin was found to be 3 kA/cm$^2$with the current equipment set up.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.121-127
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• 2001

To investigate the stability and integrity of offshore structures, it is necessary to estimates the significant ocean environmental loadings. They include hydrostatic pressure, wind, wave, current, tide, ice, earthquake, temperature, marine growth and scouring. Waves are of major importance among them because of the large forces acting on submerged parts of the structure caused by accompanying water motions. For the comparison of stress and deflection analysis tools, a vertical pile is applied under environmental loads. The analysis is concerned with SACS(Structural Analysis Computer System), ANSYS and C program. SACS and C program have nearly the same results but not ANSYS. This study shows the comparison of results obtained from 3 different approaches.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.75-82
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• 2000

A huge offshore structures such as immersed tunnel, ice-resisting wall are continuously subjected to large force from water pressure, wave action and impact loads. Composite steel-concrete structure of sandwich system has profitable advantages for a huge offshore structures. This composite structures should exhibit a high degree of strength and ductility, because of concrete confining effect and the property of steel plate. Therefore, it endures large deformation and absorbs a great deal of energy until failure. In this study, nonlinear analysis for composite steel-concrete structure of sandwich system was carried out, and certify the effects of various parameters, elastic·plastic behavior characteristic, load-carrying and failure mechanism.

• 대기
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• 제26권4호
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• pp.617-633
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• 2016

Jangbogo station is located in Terra Nova Bay over the East Antarctica, which is often affected by individual storms moving along nearby storm tracks and a katabatic flow from the continental interior towards the coast. A numerical simulation for two strong wind events of maximum instantaneous wind speed ($41.17m\;s^{-1}$) and daily mean wind speed ($23.92m\;s^{-1}$) at Jangbogo station are conducted using the polar-optimized version of Weather Research and Forecasting model (Polar WRF). Verifying model results from 3 km grid resolution simulation against AWS observation at Jangbogo station, the case of maximum instantaneous wind speed is relatively simulated well with high skill in wind with a bias of $-3.3m\;s^{-1}$ and standard deviation of $5.4m\;s^{-1}$. The case of maximum daily mean wind speed showed comparatively lower accuracy for the simulation of wind speed with a bias of -7.0 m/s and standard deviation of $8.6m\;s^{-1}$. From the analysis, it is revealed that the each case has different origins for strong wind. The highest maximum instantaneous wind case is caused by the approach of the strong synoptic low pressure system moving toward Terra Nova Bay from North and the other daily wind maximum speed case is mainly caused by the katabatic flow from the interiors of Terra Nova Bay towards the coast. Our evaluation suggests that the Polar WRF can be used as a useful dynamic downscaling tool for the simulation and investigation of high wind events at Jangbogo station. However, additional efforts in utilizing the high resolution terrain is required to reduce the simulation error of high wind mainly caused by katabatic flow, which is received a lot of influence of the surrounding terrain.