• 융복합기술연구소 논문집
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• 제2권1호
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• pp.1-6
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• 2012

The cold chain system in South-East Asia is requiring to maintain freshness of refrigerated or frozen food. In this study, Thermal storage system using Phase change material (PCM) was developed and evaluated its performance about temperature and cold keeping time. For various application of cold chain system, we developed portable cold box, cold roll container and freezing station. Keeping time on laboratory tests of portable cold box in case of refrigeration and freezing were 6 hours and 4 hours, respectively. Cold container was developed to 2.5 ton scale. Evaluation in Indonesia, it was showed to keep the setting temperature of $-10^{\circ}C$ over 40 hours at $30^{\circ}C$ of ambient air. Freezing station using PCM was kept over 24 hours under $-20^{\circ}C$.

• 대한방사선치료학회지
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• 제20권1호
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• pp.45-53
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• 2008

목 적: 본원에 2007년 10월에 설치된 토모테라피를 이용하여 치료한 환자 130명에 대하여 치료의 통계적 특성을 분석하여 종양의 부위별, 종양표적체적의 변화, 전체치료시간(overall treatment time), 초고압전산화단층촬영(Megavoltage computed tomography; MVCT)을 이용한 환자의 이동 값, 종양의 크기 변화에 따른 보정치료계획(Adaptive plan) 필요성 등에 대한 통계를 분석하여 알아보고자 한다. 대상 및 방법: 본원에서 2007년 10월부터 2008년 8월까지 토모테라피를 받은 130명의 환자를 대상으로 조사하였다. 환자의 평균 연령은 53세(최소 25세, 최고 83세)이고, 치료 부위별로 두경부(22명), 흉부(47명), 복부(25명), 골반부(11명), 골격계(25명) 로 나누었으며 MVCT는 2,702번의 총 분할조사를 치료 전 100% 시행하였고 종양의 크기변화가 큰 27명은 보정치료계획을 시행하였다. 또한 획득된 MVCT와 kV-CT를 일치시킨 후 이동된 값(X, Y, Z, roll, vector)을 치료부위와 사용된 고정기구의 평균 오차범위를 조사하였고 위치잡이(set up), MVCT, 평균 전체치료시간, 표적체적(target volume; TV)을 조사하였다. 결 과: 분석결과 환자가 카우치에 누워있는 평균시간은 22.8분, 평균 치료시간은 13.46분, 평균 보정계수(mm) X=-0.7, Y=-1.4, Z=5.77, roll=0.29, vector=8.66으로 평균 육안적종양체적(gross tumor volume; GTV)=229 $cm^3$, 평균 임상표적체적(clinical tumor volume; CTV)=564 $cm^3$으로 나타났다. 흉부, 복부, 골격계 치료환자보다 두경부 환자의 이동된 vector값이 2.96 mm적음을 알 수 있었다. 치료부위별 이동된 vector값이 두경부>골격계>복부>흉부>골반부 순서로 나타났다. 또한, 보정치료 계획을 시행한 환자는 27명, 종양이 길거나 다발성 종양환자는 39명이며 치료 시 1개의 치료계획으로 치료할 때 전체치료시간은 32분, 2개의 치료계획으로 나누어 치료 시에는 각각 21분, 19분으로 총 40분 소요되는 것을 알 수 있었다. 결 론: 고정용구의 사용과 더불어 MVCT의 적용으로 더욱 정확한 세기조절방사선치료(intensity modulated radiation therapy; IMRT)를 할 수 있었다. 또한 매일 영상을 통해 종양의 변화를 확인하여 보정치료계획을 할 수 있었으며 종양이 길거나 또는 다발성 종양, 손상위험장기(organ at risk; OAR) 근처의 치료와 급격한 선량분포의 변화를 주어야 하는 복잡한 치료를 가능하게 하였다.

• 대한방사선치료학회지
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• 제26권1호
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• pp.69-76
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• 2014

목 적 : 외부 압박을 통해 전립선암 환자의 복강 내 압력을 안정화시켜 움직임을 감소하여 치료 간(interfraction)과 치료 중(intrafraction)에 변화를 측정하여 평가하고자 시행하였다. 대상 및 방법 : 10명의 전립선환자들은 전체 치료과정동안 MVCT 스캔을 통해 치료 전과 후에 걸쳐 환자 당 60개의 영상을 획득하였고 획득한 좌우방향(X), 상하방향(Y), 전후방향(Z), 회전방향(Roll)에 대한 Shift 값들을 이용하여 복부 압박 시 치료 간 치료준비 변화와 치료 중 표적 움직임의 상호 연관성을 분석하였다. 결 과 : 치료 간의 움직임 변화는 평균 좌우방향(X)에서 $0.65{\pm}2.32mm$, 상하방향(Y)에서 $1.41{\pm}4.83mm$, 전후방향(Z)에서 $0.73{\pm}0.52mm$, 회전방향(Roll)에서 $0.96{\pm}0.21^{\circ}$로 나타났다. 치료 중 움직임 변화는 평균 좌우방향(X)에서 $0.15{\pm}0.44mm$, 상하방향(Y)에서 $0.13{\pm}0.44mm$, 전후방향(Z)에서 $0.24{\pm}0.64mm$, 회전방향(Roll)에서 $0.1{\pm}0.9^{\circ}$로 나타났다. 결 론 : 전처치과정과 외부에서 복부압박을 통한 전복부의 움직임을 제한한다면 치료동안에 내부 장기와 환자의 움직임을 감소시켜 보다 적은 여유(margin)로 계획용 표적체적(PTV)을 생성할 수 있어서 정상조직의 부작용 증가 없이 더욱 이상적인 선량 체적을 얻을 수 있을 것으로 사료된다.

• 대한기계학회논문집A
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• 제28권6호
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• pp.799-806
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• 2004

This paper presents a scheme for finding an optimal combination of design parameters affecting on the handling performance of a large truck using design of experiments. The average of the sum of peak-to-peak roll angles at the first and second part of the double lane is used as an objective function for design of experiments. Six design parameters are selected from all possible parameters affecting on the handling performance. The table of orthogonal arrays is made by 27 times simulations. A computational model of a large truck is developed by MSC/NASTRAN and MSC/ADAMS, and verified the reliability of it with the results of vehicle tests performed in a double lane change course. It is used for the simulations. Analyses of variance and factor effect of the table of orthogonal arrays are performed. This paper proposes an optimal combination of those six design parameters for improving the handling performance of the large truck.

• Elastomers and Composites
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• 제31권1호
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• pp.33-42
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• 1996

NR, NBR, and CR rubber were prepared by mixing filler in various ratios. Their vulcanization characteristics and thermal properties were studied. Vulcanization characteristics were investigated using cure curve that had been obtained from oscillating disk rheometer study. The Arrhenius law is known to describe the relationship between cure time and temperature of most elastomers. Curing could be done by the addition of sulfur, peroxides, and proper acceleratores. The optimum cure time that affects desirable values of modulus and tensile strength of the vulcanizate is taken as t90 as measured by a rheometer. Rubbers were cured in the rheometer at temperatures ranging from $130^{\circ}C\;to\;180^{\circ}C$ in order to check the validity of the curing system used. A linear relationship between ln(ts2) and ln(t90) was found for all elastomers. The term sensitivity has been used to describe the relationship between a change of ts2 to the corresponding change of t90 due to an increment of temperature. This is related to the formula of the compound.

• 한국유체기계학회 논문집
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• 제18권5호
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• pp.49-53
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• 2015

Thrust vector control is the method which generates the side force and roll moment by controlling exhausted gas directly in a rocket nozzle. TVC is classified by mechanical and fluid dynamic methods. Mechanical methods can change the flow direction by several objects installed in a rocket nozzle exhaust such as tapered ramp tabs and jet vane. Fluid dynamic methods control the flight direction with the injection of secondary gaseous flows into the rocket nozzle. The tapered ramp tabs of mechanical methods are used in this paper. They installed at the rear in the rocket nozzle could be freely moved along axial and radial direction on the mounting ring to provide the mass flow rate which is injected from the rocket nozzle. TVC of the tapered ramp tabs has the potential to produce both large axial thrust and high lateral force. We have conducted the experimental research and flow analysis of ramp tabs to show the performance and the structural integrity of the TVC. The experiments are carried out with the supersonic cold flow system and the schlieren graph. This paper provides to analyze the location of normal shock wave and distribution of surface pressure on the region enclosed by the tapered ramp tabs.

• 한국의류학회지
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• 제2권2호
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• pp.245-252
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• 1978

In order to obtain some information for solvent dyeing, polyethylene terephthalate (PET) was treated with water, tetrachloroethylene yarn (TCE), and water/TCE emulsion for three hours at the temperatures from $40^{\circ}$ to $140^{\circ}C$. The change of fine structure of substratum by measuring the shrinkage, the degree of crystallinity, the stress relacxation modulus and Young's modulus. The P.E.T. film was also treated in water (at $140^{\circ}C$) for 4 hours to stabilize the substratum. By means of film roll cyliderical method, the Disperse Blue 27 was diffused. Then, calculated the diffusion coefficient and examined the application of WLF equation. However, the temperature dependence of the shrinkage could be explain with WLF equation, the diffusion coefficient couldn't be applied the WLF equation when the substratum was stabilized. From the result, the effects on shrinkage were in the order of water

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3820-3841
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• 2018

Most of the accidents occur due to drowsiness while driving, avoiding road signs and due to driver's distraction. Driver's distraction depends on various factors which include talking with passengers while driving, mood disorder, nervousness, anger, over-excitement, anxiety, loud music, illness, fatigue and different driver's head rotations due to change in yaw, pitch and roll angle. The contribution of this paper is two-fold. Firstly, a data set is generated for conducting different experiments on driver's distraction. Secondly, novel approaches are presented that use features based on facial points; especially the features computed using motion vectors and interpolation to detect a special type of driver's distraction, i.e., driver's head rotation due to change in yaw angle. These facial points are detected by Active Shape Model (ASM) and Boosted Regression with Markov Networks (BoRMaN). Various types of classifiers are trained and tested on different frames to decide about a driver's distraction. These approaches are also scale invariant. The results show that the approach that uses the novel ideas of motion vectors and interpolation outperforms other approaches in detection of driver's head rotation. We are able to achieve a percentage accuracy of 98.45 using Neural Network.

• 열처리공학회지
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• 제34권3호
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• pp.107-115
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• 2021

Al-Si coated boron steel has been widely used as commercial hot stamping steel. When the steel is heated at 900~930℃ for 5 min in an electric furnace, thickness of the coating layer increases as a consequence of formation of intermetallic compounds and diffusion layer. The diffusion layer plays an important roll in blunting the propagation of crack from coating layer to base steel. Change in microstructure and coating layer of Al-Si coated boron steel after conductive heating with higher heating rate than electric furnace has been investigated in this study. Conductive-heated steel showed the martensitic structure with vickers hardness of 505~567. Both intermetallic compounds in coating layer and diffusion layer were not observed in conductive-heated steel due to rapid heating. It has been found that the conductive-heating consisting of rapid heating to 550℃ which is lower than melting point of Al-Si coating layer, slower heating to 900℃, and then 1 min holding at 900℃ is effective in forming intermetallic compound in coating layer and diffusion layer.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3068-3073
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• 2007

Aerodynamic forces and moments have been used to control rocket propelled vehicles. If control is required at very low speed, Those systems only provide a limited capability because aerodynamic control force is proportional to the air density and low dynamic pressure. But thrust vector control(TVC) can overcome the disadvantages. TVC is the method which generates the side force and roll moment by controlling exhausted gas directly in a rocket nozzle. TVC is classified by mechanical and fluid dynamic methods. Mechanical methods can change the flow direction by several objects installed in a rocket nozzle exhaust such as tapered ramp tabs and jet vane. Fluid dynamic methods control the flight direction with the injection of secondary gaseous flows into the rocket nozzle. The tapered ramp tabs of mechanical methods are used in this paper. They installed at the rear in the rocket nozzle could be freely moved along axial and radial direction on the mounting ring to provide the mass flow rate which is injected from the rocket nozzle. In this paper, the conceptual design and the performance study on the tapered ramp tabs of the thurst vector control has been carried out using the supersonic cold flow system and shadow graph. Numerical simulation was also performed to study flow characteristics and interactions between ramp tabs. This paper provides to analyze the location of normal shock wave and distribution of surface pressure on the region enclosed by the tapered ramp tabs.