• 대한기계학회논문집
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• 제14권5호
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• pp.1155-1165
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• 1990

본 연구에서는 롤압력과 롤토크를 예측하는 새로운 방법이 제시된다. 이 방 법은 롤 간극에서의 자세한 변형도속도의 분포를 예측할 수 있으며, 특히 롤압력과 롤 토크의 계산에 필요한 유동응력 분포도 계산할 수 있다. 이 방법을 이용하여 압연조 건과 재료성질이 롤압력, 압하력, 롤토그 등에 미치는 영향을 조사하였다. 또한, 이 방법에 의해서 예측된 결과를 참고문헌과 포항제철의 공정 데이터로부터 발췌한 실험 데이터와 비교하였으며, 유한요소 해석결과와도 비교하였다.

• 제어로봇시스템학회논문지
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• 제17권4호
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• pp.382-387
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• 2011

In this paper, a LBCC (Latter Bank Cooling Control) for the high strength steel is proposed to obtain the desirable temperature and the property of the material along the longitudinal direction of the steel on the ROT (Run-Out Table) process. A cooling valve is modeled to analyze the response of the ROT banks. The control concept is derived from a field data, a valve model considering the valve response and a TTT (Time-Temperature Transformation) diagram. The proposed control is verified from the simulation results under the various carbon quantities. It is shown through the field test of the hot strip mill that the deviation of the CT (Coiling Temperature) is considerably decreased by the proposed temperature control.

• 천문학논총
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• 제30권2호
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• pp.423-427
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• 2015

Recognition of the role of radio galaxies in the universe has been increasing in recent years. Their colossal energy output over huge volumes is now widely believed to play a key role not only in the formation of galaxies and their supermassive black holes, but also in the evolution of clusters of galaxies and, possibly, the cosmic web itself. In this regard, we need to understand the inflation of radio bubbles in the hot gas atmospheres of clusters and the importance of the role that radio galaxies play in the overall energy budget of the intracluster medium. Here, we present results from X-ray and radio band observations of the hot gas atmospheres of powerful, nearby radio galaxies in poor clusters.

• 한국유체기계학회 논문집
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• 제12권2호
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• pp.17-23
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• 2009

The program using $C/C^{++}$ which could calculate 3-D velocities from data of the flowfield obtained by a slant hot-wire has been developed. The characteristic of the exit flowfield of a circular nozzle with a curved surface was investigated. From the result, the inward-flow was verified at adjacent layers near the boundary of the exit flowfield of a circular nozzle in Id and outward-flow was sensed gradually from down-flow of Id. Similarity of the nondimensional velocity profile properlly could be obtained except near Id and the virtual origin reasonably could be obtained.

• 소성∙가공
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• 제10권1호
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• pp.35-41
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• 2001

The high temperature deformation behavior of SCM 440 can be characterized by the hot torsion test in the temperature ranges of $900^{\circ}C$~$1100^{\circ}C$ and strain rate ranges of 0.05/sec~5/sec. The aim of this paper is to establish the quantitative equation of the volume fraction of dynamic recrystallization (DRX) as a function of processing variables, such as strain rate ($\varepsilon$), temperature (T), and strain ('$\varepsilon$). During hot deformation, the evolution of microstructure could be analyzed from work hardening rate ($\theta$). For the exact prediction of dynamic softening mechanism the critical strain ($\varepsilon_c$), the strain for maximum softening rate ($\varepsilon^*$ and Avrami' exponent (m') were quantitatively expressed by dimensionless parameter, Z/A, respectively. The transformation-effective strain-temperature curve for DRX could be composed. It was found that the calculated results were agreed with the experimental data for the steel at any deformation conditions.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.273-276
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• 2006

To generate electricity from wind energy, wind turbine generally has a rotor blade. Since this rotor blade is a kind of the rotating machinery, the wake from the rotor is very Important role in the side of the aerodynamic performances. Thus the study about wake is essential to analyze wind turbine aerodynamics. In this study wake characteristics are analyzed by hot-wire probe in the K.A.F.A(Korea Air Force Academy) wind tunnel. It is possible to analyze the wake characteristics by hot-wire probe from acquiring the velocity fluctuations at given positions in the flow. This velocity data are arranged by trigger signal at same azimuth of the blade in periodic manner of the rotor blade. From this various wake characteristics are found : radial and axial position of the tip vortex, vortex core characteristics in the flow etc.

• 대한물리치료과학회지
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• 제24권2호
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• pp.45-52
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• 2017

Purpose : Most of the moderns have been spent sedentary life style in front of desk or on the chairs, so that their hamstring muscles are shorted commonly and the shortness of hamstring muscles are caused to some problems in functional activities. The purpose of this study was to compare the effectiveness of thermotherapy with hot-pack and ultrasound on the tightness of hamstring muscles in individuals with hamstring tightness. Method : Twenty-eight persons with hamstring tightness participated in this study. They were randomly assigned to three exercise groups: stretching group(n=10), hot-pack group(n=9), and ultrasound group(n=9). Before experiment, this study measured the angle of hip flexion using a inclinometer in all participants. Stretching group conducted actively stretching on their shorted leg for 30 seconds, 3 times, and rest for 10 seconds between each exercises. Hot-pack group have applied hot-pack($70{\sim}75^{\circ}C$) on shorted hamstring muscles for 20 minutes before stretching exercise. Ultrasound group have applied therapeutic ultrasound(1 MHz and 1.5W/cm2) on shorted hamstring muscles for 10 minutes before stretching exercise. All data was analysed using one-way repeated ANOVA. Result : The results revealed that ultrasound therapy before stretching is more effective to the flexibility on hamstring muscles than hot-pack before stretching and stretching only. Conclusion : The results of this study show that thermotherapy with therapeutic ultrasound will be effective on the shortness of hamstring muscles before stretching exercise.

• Food Science and Biotechnology
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• 제15권1호
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• pp.33-38
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• 2006

This study was performed to provide basic rheological data of dandelion root concentrates in order to predict their processing aptitude and usefulness as functional foods material. The hot water and 70% ethanol extracts of dandelion root were concentrated at 5, 20, and 50 Brix, and their static viscosity, dynamic viscosity, and Arrhenius plots were investigated. Almost all hot water concentrates showed the typical flow properties of a pseudoplastic fluid, but evaluation using the power law model indicated that the 70% ethanol concentrates showed a flow behavior close to a Newtonian fluid. The apparent viscosity of hot water and 70% ethanol concentrates decreased with increasing temperature. Yield stresses of hot water and 70% ethanol concentrates by Herschel-Bulkley model application were in the range of 0.026 - 1.368 Pa and 0.022 - 0.238 Pa, respectively. The effect of temperature and concentration on the apparent viscosity was examined by Arrhenius equation. The activation energies of hot water and 70% ethanol concentrates were in the range of $8.762-23.778{\times}10^3\;J/mol{\cdot}kg$ and $3.217-20.384{\times}10^3\;J/mol{\cdot}kg$ with increasing concentration, respectively. Storage (G') and loss (G") moduli were generally increased with increasing frequency. For the 70% ethanol concentrates, G" predominated over G' at all applied frequencies and so they showed the typical flow behavior of a low molecular solution. However, for the hot water concentrates, G' predominated over G" at more than 1.9 rad/sec (cross-over point) and so they showed the typical flow behavior of a macromolecular solution.

• 한국식생활문화학회지
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• 제23권4호
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• pp.479-488
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• 2008

Some biological activities such as an electron donating capacity, the contents of total polyphenol compounds and flavonoids, fibrinolytic activity and $\alpha$-glucosidase inhibitory activity have been detected in hot water extracts of Ligularia fischeri and Angelica gigas Nakai. To increase the usefulness of the functional ingredients for prevention and improvement of some metabolic disorders, ethanol-treated hot water extracts of Angelica gigas Nakai were prepared. A hot water extract of Ligularia fischeri has 92% of electron donating capacity, 39.4 mg/g of total polyphenol compounds, 24.8 mg/g of flavonoids and 29.8% of $\alpha$-glucosidase inhibitory activity, but no fibrinolytic activity. A hot water extract of Angelica gigas Nakai has 94.7% of electron donating capacity, 5.8 mg/g of total polyphenol compounds, 2.6 mg/g of flavonoids, 0.48 plasmin units of fibrinolytic activity and no $\alpha$-glucosidase inhibitory activity. However, with partial purification using cold ethanol treatment, the $\alpha$-glucosidase inhibitory activity of Angelica gigas Nakai was increased to 70.5%. Thus, we expected a more useful effect with the use of the addition of a cold ethanol-treated Angelica gigas Nakai extract. The L, b values of cold buckwheat noodles using a mixture of 0$\sim$3% of Ligularia fischeri powder and 0.5% of an ethanol-treated hot water extract of Angelica gigas Nakai were decreased with the addition of an increasing amount of Ligularia fischeri powder. Among the mechanical qualities, only adhesiveness was significantly higher in 3% Ligularia fischeri noodles. From sensory evaluation data, it was determined that these two functional ingredients did not ruin the color, texture, and overall acceptance of the cold buckwheat noodles. A higher amount of the extracts improved the quality of the product with little added cost.

• Spatial Information Research
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• 제8권2호
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• pp.213-232
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• 2000

범죄발생 자료는 본질적으로 지리적인 속성을 내포하고 있기 때문에 범죄분석에 있어서 공간적 패턴을 파악하는 것은 매우 중요하다. 본 연구에서는 GIS의 지도화 기능과 공간통계 기법을 접목하여 범죄발생의 공간적 양상을 규명할 수 있는 ¨범죄분석 지리정보시스템¨의 원형(prototype)을 제작하였다. 이 시스템은 DBMS와 GIS를 연동하는 구조로서 점 자료(point data)의 공간분포 탐색, 범죄다발지역(hot-spot)의 지도화, 범죄발생의 군집성 분석 그리고 면(area)단위 집계자료 분석 등의 기능들로 구성된다. 시스템의 설계와 구현 과정은 객체지향 방법론에 의거하였으며, 본 시스템 이외에도 현재 개발 중에 있는 웹 기반 3-Tier 구조의 시스템은 범죄분석과 인터넷 지리정보시스템에 있어서 중요한 역할을 담당할 것으로 전망된다.