• Journal of the Korean Physical Society
• /
• 제73권10호
• /
• pp.1584-1588
• /
• 2018

During hyperthermia therapy, cancer cells are heated to a temperature in the range of $40{\sim}45^{\circ}C$ for a defined time period to damage these cells while keeping healthy tissues at safe temperatures. Prior to hyperthermia therapy, the amount of heat energy transferred to the cancer cells must be predicted. Among various non-invasive methods, the thermal prediction method using the specific absorption rate (SAR) is the most widely used method. The existing methods predict the thermal distribution by using a single constant for the mass density in one organ through assignment. However, because the SAR and the bio heat equation (BHE) vary with the mass density, the mass density of each organ must be accurately considered. In this study, the mass density distribution was calculated using the relationship between the Hounsfield unit and the mass density of tissues in preceding research. The SAR distribution was found using a quasi-static approximation to Maxwell's equation and was used to calculate the potential distribution and the energy distributions for capacitive RF heating. The thermal distribution during exposure to RF waves was determined by solving the BHE with consideration given to the considering contributions of heat conduction and external heating. Compared with reference data for the mass density, our results was within 1%. When the reconstructed temperature distribution was compared to the measured temperature distribution, the difference was within 3%. In this study, the density distribution and the thermal distribution were reconstructed for the agar phantom. Based on these data, we developed an algorithm that could be applied to patients.

• 전자공학회논문지
• /
• 제53권6호
• /
• pp.155-166
• /
• 2016

전자유도 가열시설에서 정밀하고 일정한 주파수 성분에 의해 가열물체에 발열을 유도하려면 LC공진회로 설계단계에서 출력 주파수에 대한 커패시터의 정전용량(C)과 워크코일의 유도계수(L) 설정이 중요하다. 하지만 고유의 발열계수를 가진 물체의 가열위치와 범위에 직접유도를 하는 워크코일은 고정적으로 설계되는 반면 커패시터는 가변되도록 설계되어야만 전체장비의 활용도가 높아진다. 본 논문에서는 $1000V_{MAX}$ 최대전압과 $200I_{MAX}$ 전류에서 최대 700kHz의 고주파 LC공진 출력이 되도록 커패시터 내부구성 원자재 선정 및 공정설계 단계까지 단일전극 용량별 샘플을 추출하였다. 그리고 정전용량 규격변화에 따라 주파수 변화특성과 출력 파라메타 결과를 바탕으로 HF-LC공진용 전도냉각 커패시터의 최적설계를 위한 관계를 증명하는 기초 실험결과를 제시하였다.

• 대한기계학회논문집B
• /
• 제39권4호
• /
• pp.309-316
• /
• 2015

가열식 액체용 질량유량계측기(LMFM, Liquid Mass Flow Meter)에 대하여 수치해석적으로 분석하였으며 실험을 통하여 검증하였다. 기존의 기체용 질량유량계측기(GMFM, Gas Mass Flow Meter)와 동일한 구조로 설계하였으나 계측온도차는 기체용에 비하여 정 반대의 특성을 나타낸다. 기체는 열용량이 작아서 계측관벽을 통한 전도열전달이 기체의 유동에 따른 대류열전달에 대응할 정도이므로 이들 상호작용의 결과 상 하류 써미스터의 온도차가 질량유량에 비례한다. 반면, 열용량이 큰 액체의 경우 대류열전달이 지배적이 되어 계측관벽을 통한 전도열전달이 무시되며, 결과적으로 온도차가 질량유량에 반비례한다. 계측관경과 히터의 권선폭은 LMFM 의 중요한 설계인자로서 각각 최적화가 필요하다. 최적화 설계를 통하여 제작한 계측기는 반도체 생산장비의 극소유량 정밀제어 및 공급용으로 사용할 수 있다.

• 대한한방내과학회지
• /
• 제21권5호
• /
• pp.747-763
• /
• 2000

through a literal study upon Arrhythmia between east and west medicine, the results were as follows 1. Arrhythmia is not only irregular cardiac beat but disorder of cardiac impulse making and conduction disturbance. it means almost irregularity of interval between two beat 2. In the east medicine, arrhythmia is represented various category as palpitation, continuous palpitation, dizziness, consumption which give the first consideration by the accompanied symptoms. A separate way in a diagnostics it become a base of diagnosis of diseases and decision of prognosis by the examination of pulse 3. In the west medicine, Arrhythmia is classified as disorder of heart rate, rhythm, conduction disturbance or tachycardia, bradycardia and it is concomitant with fatigue, palpitation, dyspnoea, syncope, chest discomfort 4. The diagnostic study of pulse condition which represent arrhythmia was started from $\mathbb{<}$Nae-Kyung$\mathbb{>}$ and it was revealed as pulse condition of rapid pulse, slow pulse, swift pulse, running pulse, knotted pulse, intermittent pulse etc. Out of them running pulse, knotted pulse, intermittent pulse which obviously are concomitant with irregularity of interval are clinically meaningful in a conditions of disease and decision of prognosis. and the significance of these pulse condition are transformed through the changes of the times 5. According to cause of disease it is classified by Arrhythmia(running pulse, knotted pulse, intermittent pulse) due to heat, cold, phlegm, deficiency(or insufficiency) and There are three categories of etiological factor that is, endogenous, exogenous and non-exo-endogenous factor. the endogenous factor is insufficiency of the heart Ki, deficiency of both Ki and blood, intemal stagnation of phlegm and fluid, stagnation of seven emotions. the exogenous factor is caused by stagnation of Ki and blood by six exogenous pathogenic factor and the non-exo-endgenous factors are improper diet, overstrain, traumatic injury. A cause of arrhythmia in western medicine are a organic and pathological change of the heart itself and malfunction of the autonomic nervous system.

• 한국의류학회지
• /
• 제29권7호
• /
• pp.918-925
• /
• 2005

The following are the results from the infrared body temperature image test to verify the changes in facial temperature according to call duration with a cellular phone. As for the body temperatures, it appears to be the mean value at the upper central point of phone's battery among 7 different points that are measured, and to be the highest at srernocleido-mastoid and scapular trapezius muscle triangle zone$(34.25^{\circ}C\; and\;34.05^{\circ}C\;each)$. The changes of body temperature according to the time duration shows that the body temperature rises according to the length of phone use because of the heat emitted from the battery. As for the temperature changes according to blocking materials, the one without processing appears to be higher in the mean temperature compared to the others that are processed, NSS(Nano Silver Silk) and NSG(Nano Silver Silk Gold) appear to be the lowest in the temperature to show the best blocking property. As for the temperature changes according to measuring points, it appears to be the highest at P4, P5 with all materials, and one with NSG to be the lowest at Pl, P2, P3, and one with NSS to be the lowest at P3, P4, P5, P6, which is due to the thermal conduction of Au and Ag. And the mean temperature at each point appears to be different according to the materials. Therefore, the study conducted with human participants requires a proper particle size of it which would not penetrate cellular tissues and a proper binder and binding treatment for it, to prevent the physical fatigues and the potential diseases. However, it is highly required for back-up researches to verify various aspects in applying nano silver to textile products.

• Agricultural and Biosystems Engineering
• /
• 제4권2호
• /
• pp.58-65
• /
• 2003

An understanding of the cooling requirements of horticultural commodities begins with adequate knowledge of their biological responses. All fresh horticultural products are living organisms, carrying on the many biological processes that are essential to the maintenance of life. The pre-cooling is essential technique for the construction of cold chain system, which is necessary to maintain marketing quality of fresh produces during the transportation and distribution. The purpose of this study is to develop the pressure cooling tunnel using conveyer for the reduction of labor and improvement of pre-cooling efficiency. Performance of developed facility was tested for the strawberries, tomatoes and Chinese cabbages. Cooling ratio as a result of pre-cooling efficiency was 1.57, 1.56 and 1.32 for strawberries, tomatoes, and Chinese cabbages respectively. Cooling ratio decreased with increasing the distance of heat conduction from surface to center. The cooling ratio of Chinese cabbages was lower than that of fruit because of its head and leaf. In aspect of cooling uniformity, there was no significant difference of final temperature among inlet, outlet and middle layers of cold air in fresh produces. After pre-cooling treatment, quality changes were measured for the weight loss, Vit. C content, and titratable acidity. The quality of pre-cooling treatment was better than that of non-treatment and was kept on well during long-term storage.

• 디지털콘텐츠학회 논문지
• /
• 제19권4호
• /
• pp.615-620
• /
• 2018

당뇨병성 다발성 신경병증 환자들을 진단하는 전류지각 역치 시험과 진동 감각 지각 역치의 임상학적 유용성에 대한 평가는 당뇨병성 다발성 신경병증에 대한 진단방법 중의 하나이다. 현재까지 당뇨병성 다발성 신경병증 환자들에 대해 몇 가지 방법들이 사용되어 왔는데, 예를 들면, 하지 신경병증 장애 시험, 신경전도 시험, 냉각감지 역치 시험, 열-고통 역치 시험 등을 들 수 있다. 그러나, 이들 대부분의 시험은 고가이거나 시험하는데 많은 시간을 필요로 한다. 본 논문에서는 진동 감지 능력을 평가하는 새로운 기구가 소개되고, 이를 위해 환자의 말초 신경을 자극하는 보이스 코일 모터(voice coil motor)와 전류 증폭기를 제작하였다. 또한, 당뇨병성 다발성 신경병증 환자들의 정량적 진동 감지 수준을 측정하기 위하여 진동 감지 역치 시험을 센싱하고 구동하는 소프트웨어가 개발되었다.

• 대한기계학회논문집B
• /
• 제24권9호
• /
• pp.1219-1226
• /
• 2000

An efficient method is developed for plunger thermal cycle analysis in repeated forming process of the TV glass. The plunger undergoes temperature fluctuation during a cycle due to the repeated contact and separation from the glass, which attains a cyclic steady state having same temperature history at every cycle. Straightforward analysis of this problem brings about more than 80 cycles to get reasonable solution, and yet hard to setup stopping criteria due to extremely slow convergence. An exponential fitting method is proposed to overcome the difficulty, which finds exponential function to best approximate temperature values of 3 consecutive cycles, and new cycle is restarted with the fitted value at infinite time. Numerical implementation shows that it reduces the number of cycles dramatically to only 6-18 cycles to reach convergence within 10 accuracy. A system for the analysis is constructed, in which the thermal analysis is performed by commercial software ANSYS, and the fitting of the result is done by IMSL library. From the parametric studies, one reveals some important facts that although the plunger cooling or the glass thickness is increased, its counter part in contact is not much affected, duo to the low thermal conductance of the glass.

• 한국건축시공학회지
• /
• 제16권3호
• /
• pp.193-199
• /
• 2016

본 연구는 산업폐기물로 발생되는 굴 패각과 건식공정 바텀애시를 골재로 활용하여 제작된 내화보드의 가열실험을 통한 성능에 관한 연구이며 다음과 같은 결론을 도출하였다. 전기로 가열실험을 통해 나타난 시험편의 이면온도는 $300^{\circ}C$ 가열상황에서 $103.1{\sim}125.1^{\circ}C$로, $600^{\circ}C$의 가열상황에서 $201.1{\sim}210.1^{\circ}C$로, $900^{\circ}C$의 가열상황에서 $249.2{\sim}276.9^{\circ}C$의 범위로 나타났다. 내화보드 시험편의 경우 일정온도상승 이후 유지되는 것으로 나타나 사용재료들의 경우 내화성능이 발휘되는 것으로 판단된다. 실험의 결과로 유추할 때, 입자의 크기가 작을 경우 $600^{\circ}C$까지는 내화성능이 상대적으로 우수하지만, 그 이상의 온도에서는 입자의 크기가 큰 경우 많은 공극을 포함하여 열전달이 지연되는 것으로 판단된다.

• 한국전산유체공학회지
• /
• 제21권2호
• /
• pp.112-119
• /
• 2016

NEXTSat-1 is the next-generation small-size artificial satellite system planed by the Satellite Technology Research Center(SatTReC) in Korea Advanced Institute of Science and Technology(KAIST). For the control of attitude and transition of the orbit, the system has adopted a RHM(Resisto-jet Head Module), which has a very simple geometry with a reasonable efficiency. An axisymmetric model is devised with two coil-resistance heaters using xenon(Xe) gas, and the minimum required specific impulse is 60 seconds under the thrust more than 30 milli-Newton. To design the module, seven basic parameters should be decided: the nozzle shape, the power distribution of heater, the pressure drop of filter, the diameter of nozzle throat, the slant length and the angle of nozzle, and the size of reservoir, etc. After quasi one-dimensional analysis, a theoretical value of specific impulse is calculated, and the optima of parameters are found out from the baseline with a series of multi-physical numerical simulations based on the compressible Navier-Stokes equations for gas and the heat conduction energy equation for solid. A commercial code, COMSOL Multiphysics is used for the computation with a FEM (finite element method) based numerical scheme. The final values of design parameters indicate 5.8% better performance than those of baseline design after the verification with all the tuned parameters. The present method should be effective to reduce the time cost of trial and error in the development of RHM, the thruster of NEXTSat-1.