• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.08a
• /
• pp.119-125
• /
• 2004

Radiant tube heaters are widely used for indirect heating in heat treatment processes such as continuous annealing line(CAL) or continuous galvanizing line(CGL). Main issues for radiant tube are temperature uniformity, lifetime, thermal efficiency. To achieve higher heat release, the radiant tubes are fired at a higher fuel rate and therefore local overheating occur. A numerical simulation based on a commercial code FLUENT has been performed to investigate local overheating of radiant tube heaters. To minimize local overheating, the effects of radiating fins, flue gas recirculation(FGR), two-stage combustion were investigated. More uniform temperature distribution was achieved in the longitudinal direction within the tube with radiating fins and this contributed to increase the life of radiant tubes. Furthermore, the radiant tube with radiating fins was proven to be more efficient than the one without fins. The effects of flue gas recirculation and two stage combustion on the efficiency of the radiant tube were also considered and the results were presented.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.5 no.3
• /
• pp.392-403
• /
• 2013

For the analysis of radiating noise problems in medium-to-high frequency ranges, the Energy Flow Boundary Element Method (EFBEM) was developed. EFBEM is the analysis technique that applies the Boundary Element Method (BEM) to Energy Flow Analysis (EFA). The fundamental solutions representing spherical wave property for radiating noise problems in open field and considering the free surface effect in underwater are developed. Also the directivity factor is developed to express wave's directivity patterns in medium-to-high frequency ranges. Indirect EFBEM by using fundamental solutions and fictitious source was applied to open field and underwater noise problems successfully. Through numerical applications, the acoustic energy density distributions due to vibration of a simple plate model and a sphere model were compared with those of commercial code, and the comparison showed good agreement in the level and pattern of the energy density distributions.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.5
• /
• pp.107-114
• /
• 2006

This paper investigates the radiating source of electro-magnetic waves in the cabin of automobile with spark ignition engine. Front seats are very close to the engine room where electro-magnetic waves are expected to be radiating. But front seat area is believed to be a blind zone, which is not affected by radiating electro-magnetic waves, because a bulk board and floor board shield the front seat area. The level and frequency spectrum of electro-magnetic waves are measured at the passenger seat and the engine room. The measured frequency range is $145{\sim}365MHz$. As a results, the level of the electro-magnetic waves of automatic transmission vehicle is greater than -82dBm. The shapes of frequency spectrum of both engine room and passenger seat are look alike. But the level of electro-magnetic waves of manual transmission vehicle is less than -82dBm and the shapes of frequency spectrum of engine room and passenger seat are different to each other. From these results, we can say that any mal-function caused by electro-magnetic waves in the automobile cabin are only possible for automatic transmission vehicle. Also, it is believed that the radiating source of electro-magnetic waves is inside the vehicle. Thus, based on the transmission line theory, this paper presumably concludes that the cables which connect all the components inside a automatic transmission vehicle must be a radiating source of electro-magnetic waves in the cabin.

• Journal of Korean Medicine Rehabilitation
• /
• v.20 no.4
• /
• pp.139-146
• /
• 2010

Objectives : To compare the differences between the symptoms and the findings of MRI(magnetic resonance imaging) and x-ray, we studied the patients with neck pain or radiating pain, which has been diagnosed as cervical herniated disc recently. Methods : We randomly selected among the 143 patients with x-ray and cervical spine(C-spine) MRI films who have visited Ja-seng hospital with neck pain and neck and radiating pain from April 1 of 2010 to May 1. We used SPSS 13.0 for windows in analyzing statistical data of study results and the level of significance was below 0.05. Results : 1. There were no significant differences between the presence of radiating pain and the amount of cervical herniation(p>0.05). 2. If the finding of a x-ray showed narrowing, based on MRI findings, the amount of herniation was more severe(p>0.05). 3. There were no significant differences between the presence of radiating pain and the findings of x-ray(p>0.05). 4. Among the 143 cases, which showed findings beside HIVD(herniation of intervertebral disc) were 13 cases. 88 cases of straightening(61.5%). 78 cases of uncovertebral joint arthrosis(54.5%). 25 cases of stenosis(17.5%), 13 cases of retrolisthesis(9.1%), 8 cases of osteophyte(6.6%), 4 cases of spondylolisthesis(2.8%), 2 cases of hemangioma(1.4%), 3 cases of OPLL(ossification of posterior longitudinal ligament)(2.1%), 2 cases of block vertebrae(1.4%), 2 cases of spondylitis(1.4%), 1 case of kyphosis(0.1) and 1 case of ligamentum flavum hypertrophy(0.1%). Conclusions : The findings from this study suggest that there was no relation between radiating pain and radiological result. On the other hand, diagnosis of x-ray and MRI showed significant relevance. The narrower disc space there were, the severer the state of herniation there existed.

• Composites Research
• /
• v.26 no.4
• /
• pp.259-264
• /
• 2013

This study manufactured the radiating element of multi-band antenna skin structure which satisfy electrical and mechanical performance and is made by double injection molding process. Structural test including impact and buckling test is carried out and stress analysis is simulated to evaluate safety of radiating element for the axial and shear loads, when changing of the skin structure is occurred by the external force. To predict allowable load of structure and evaluate safety on impact and buckling, experimental and analytic method is used in strength analysis of structure.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.16 no.2
• /
• pp.34-39
• /
• 2010

Purpose : The purpose of this study is to find out the evidence concerning the effectiveness of manual therapy intervention in the treatment of low back pain related to spondylolisthesis Methods : 12men with lumbar pain from L5~S1 spondylolisthesis of 2 or 3 grade were treated during 12-week period. The manual therapy applied twice per week. The results of back and radiating pain were measured by VAS, and abdominal muscle strength was measured by Power track II. The measurement of degree of slip in spondylolisthesis was confirmed by the lateral view of X-ray and took a measurements of the anterior displacement of a vertebral body in relation to the vertebral below. Results : 1. There was significant decrease in the back and radiating pain.(p<0.05) 2. There was significant increase in the abdominal muscle strength.(p<0.05). 3. There was significant decrease in the degree of the anterior displacement. Conclusion: The intervention of manual therapy for lumbar spondylolisthesis is effective in back pain, radiating pain, abdominal muscle strength and degree of the anterior displacement. So, nonsurgical treatment should be attempted before surgical treatment.

• Journal of Biomedical Engineering Research
• /
• v.36 no.3
• /
• pp.69-78
• /
• 2015

Ultrasonic physiotherapy systems should comply with IEC 60601-2-5(particular requirements for safety of ultrasonic physiotherapy equipment) standard for safety of patients and clinical performances. One of the most important parameters in the standard is the effective radiating area ($A_{ER}$). It has to be measured in accordance with IEC 61689 (field specifications and methods of measurement in the frequency range 0.5MHz to 5MHz). Typical ultrasonic physiotherapy system works in the frequency range 1MHz ~ 3MHz to comply with the IEC 61689. However, ultrasonic physiotherapy system using frequencies over 5MHz is out of the IEC 61689's scope. That is, even if such ultrasonic physiotherapy systems are developed by demands of the market, there is no standard to apply. It is the motivation for this study. Whereas there are other parameters to be considered, this study focuses on the effective radiating area and shows effectiveness of applying IEC 61689 in measuring effective radiating area of ultrasonic physiotherapy systems using frequency range over 5MHz by comparing the results of computer simulation and experiment. Results of this study shows that applying the IEC 61689 standard to ultrasonic physiotherapy system using frequency range over 5MHz is possible.

• Journal of IKEEE
• /
• v.24 no.3
• /
• pp.917-920
• /
• 2020

In this paper, we studied the derivation method of isoflux radiation for a planar array antenna. The presented array antenna was designed for considering of 1U-sized CubeSAT with Ku-band communications. For the presented array antenna, 8×8 radiating elements were arranged, and the distance between radiating elements was set of half-wavelength. The excited current weighting for each radiating elements was calculated by the signal processing technique used in the design of the low-pass filter. As a result of analysis of the method proposed in this paper, it was confirmed that a seamless isoflux pattern can be derived.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.49 no.7
• /
• pp.375-381
• /
• 2000

In this paper, we described the characterization of High-Tc Superconducting(HTS) microstrip antenna using non-radiating edge feeding technique and reported the microwave properties of HTS antennas with temperature. To do this, we prepared the $YBa_2Cu_3O_{7-x}$ superconducting thin film on MgO substrate using pulse-laser deposition techniques. The HTS microstrip antenna using non-radiating feeding technique was fabricated using chemical wet-etching. Then it was compared with identical antenna patterned with evaporated gold. The diverse measured results have been reported in terms of the input impedance, resonant frequency and return loss. In additional, at around the critical temperature, the effect of kinetic inductance which affect the resonant characteristic of the HTS microstrip antenna was reported.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.6
• /
• pp.1381-1389
• /
• 1988

The heat transfer by simultaneous conduction, convection and radiation between flame and fuel surface in a thermally radiating medium is investigated theoretically. The flame and fuel surface are assumed to be diffuse, gray, infinite, isothermal, parallel surfaces separated by a finite distance. The space between the plates is supposed is formulated exactly in terms of simultaneous interior-differential equations. The numerical results reveal the effect of the system parameters on the heat transfer characteristics and the temperature distributions. The numerical results reveal that the optically thick radiating medium has a blocking effect on the total beat transfer. The temperature distributions are observed to be convex upward for an optically thick radiating medium as the alberto decreases.