• Journal of rehabilitation welfare engineering & assistive technology
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• v.3 no.1
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• pp.49-53
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• 2009

In this paper, we compared wheelchair seating system between wheelchair users with cerebral palsy and spinal cord injuries. Wheelchair seating system is divided into three parts, seating components, seating cushion, and special functions. Seating components are composed of 10 sections, such as headrest, footrest, etc. There are 4 seating cushions including gel, form, hybrid, and air. Also leg elevation, seat elevation, tilt-in-space, reclining, and standing are special function of the wheelchair. There are 10 wheelchair users, 5 with celebral palsy, and 5 with spinal cord injuries who have participated in this study. 10 wheelchair users have been customers of rehabilitation technology center in national rehabilitation center. On the result, SCI group mostly uses headrest, and Humeral blocks (seating components), air cushion (seating cushion), and tilt in space, reclining (special functions). On the other hand, CP group uses adductor, abductor, and pommel (seating components), form cushion (seating cushion), and some of CP group uses reclining (special functions)

• Microbiology and Biotechnology Letters
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• v.29 no.4
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• pp.240-247
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• 2001

The effect of microsparged aeration in mammalian cell bioreactor on the oxygen transfer rate and cell viability was studied. The microspargers with differ- ent micron-sized pores were used to supply oxygen to the medium. The oxygen transfer coefficients (k$_{L}$a) measured in the bioreactor were markedly increased, which is due to the increase of the contacting area between air bubbles and liquid medium when the pore size of microsparger decreases. When the impellers of two different types (square-pitch marine impeller and $45^{\circ}$ pitched flat blade impeller) were used for agitation, the k$_{L}$a values were slightly higher with the marine impeller than with the blade impeller. The detrimental effect of direct gas sparging with microsparger on mammalian cells was investigated in bubble columns with various air flow rates and different pore sized microspargers. The first-order cell death rate constant ($k_{d}$ /7) was shown to be directly proportional to the air flow rate and inversely proportional to the pore size. During the cultivation of hybridoma cells using microsparger with the pore size of $0.57\mu$m in the mammalian cell culture bioreactor, the continuous sparging caused the cell death and suppressed the cell growth. However, cells grew normally and cell viability was maintained above 90% in the logarithmic phase when the air was intermittently sparked in order to maintain the dissolved oxygen level above 20%.

• Bulletin of Food Technology
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• v.25 no.2
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• pp.116-128
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• 2012

식품동결에 의한 품질손상에 있어 크게 영향을 미치는 인자 중의 하나가 체적변화에 의한 조직 파괴이므로 식육 및 과채류의 냉동시 내부압력에 따른 조직파괴를 방지하기 위한 기초연구로 다양한 동결방법에 따른 내부압력 변화에 대하여 조사한 결과, 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 8~10 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 따라 1.84~2.32 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 내부압력 값은 약 1~4 psig 수준으로 균온처리하지 않은 우육에 비하여 매우 적게 나타났으며, 동결소요시간도 약 10~20% 정도 짧게 나타났다. 그리고 균온처리 및 다양한 동결방법에 따른 동결식육의 조직과 냉동냉장 중의 품질변화를 비교 검토한 결과, 동결방법에 따른 드립손실율은 우육의 경우 정지공기식으로 처리한 시료는 타 처리구에 비해 계속 높게 나타났으며, 돈육은 우육에 비해 상대적으로 드립손실량이 적게 나타났으나 송풍식으로 처리한 시료에서 저장 40일째, 7.39%로 가장 높게 나타났다. 동결 우육 및 돈육의 pH변화는 뚜렷한 차이를 나타내지 않았으며, VBN 및 TBA값에 있어서는 균온 처리한 시료가 완만 및 급속동결 처리한 타 시료에 비해 저장 200일까지 가장 변화가 없었다. 동결저장온도의 상하변동에 있어서는 온도변동 횟수가 증가할수록 pH 및 수분함량은 뚜렷한 변화가 없었으나 드립손실율, VBN 및 TBA값은 온도 변동횟수가 증가할수록 서서히 증가하는 경향을 보여 주었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.123-130
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• 2015

This paper presents a new formulation for transient simulations of microwave propagation in heterogeneous unbounded domains. In particular, perfectly-matched-layers(PMLs) are introduced to allow for wave absorption at artificial boundaries used to truncate the infinite extent of the physical domains. The development of the electromagnetic PML targets the application to engineering mechanics problems such as structural health monitoring and inverse medium problems. To formulate the PML for plane electromagnetic waves, a complex coordinate transformation is introduced to Maxwell's equations in the frequency-domain. Then the PML-endowed partial differential equations(PDEs) for transient electromagnetic waves are recovered by the application of the inverse Fourier transform to the frequency-domain equations. A mixed finite element method is employed to solve the time-domain PDEs for electric and magnetic fields in the PML-truncated domain. Numerical results are presented for plane microwaves propagating through concrete structures, and the accuracy of solutions is investigated by a series of error analyses.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.171-178
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• 2015

The disk cover is installed to protect brake disk and calliper and it's removed right before delivering to customers. The temperature of disk cover was measured driving test vehicles(2000cc, diesel) in this study. The highest temperature measured for the driving test(120km/h-braking(0.3G)-stop-120km/h-braking(0.5G)-stop) was $260{\sim}270^{\circ}C$ in the upper part of the disk cover and the temperature varied considerably around the disk cover. It can be inferred from this temperature distribution around the cover that the major heat transfer from hot disk to cover was through convection. In other words, the hot air generated by braking friction moved up to the upper part of the disk cover. And only the upper area of the disk cover was melted down during this driving test. The thickness of disk cover was increased to 1.0mm from 0.7mm and 1 paper of masking tape was pasted in the upper region of the disk cover. Then the cover endured the heated air formed by braking friction during the driving test.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1886-1896
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• 1991

This paper presents a method to predict the flying height of the head slider in a hard disk drive. Quantitative predicts of the flying height according to the variations of the external load and the disk velocity have been done by numerical computation. In addition, the magnitude of the external load to keep flying height constant were also suggested. The Modified Reynolds' equation driven from hydrodynamic lubrication theory under slip flow condition was used to describe air-bearing system under the slider. To solve the equation, a Finite Volume Method (FVM) has been applied. To determine the final minimum flying height and pitch angle of the head slider, the Secant iteration method is used which update initial guess of the minimum flying height and pitch angle of the slider. In this study, the model head slider has been selected from a real hard disk drive which is equipped in many commercial personal computers. As a result, as the disk velocity increases at constant external load, the minimum flying height and the pitch angle increase due to the in crease of the air-bearing force at the bottom of slider.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.163-168
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• 2001

Due to aging, adhesively bonded and riveted aircraft lap joints can contain distends, cracks around rivet holes, fatigue induced flaws, and corrosion. It is required for the safety of aircraft to inspect these defects through the whole region of mint in rapid speed. Bond quality or adhesively bonded and riveted aluminum lap splice joints is investigated using non-contact remote ultrasonic nondestructive evaluation (NDE). Non-contact ultrasonic tests are performed using laser generation and air-coupled transducer detection. A Q-switched Nd:YAG laser and a periodic transmission mask are used to generate a selected Lamb mode. The Lamb wave is generated on one side of the lap splice joint, propagates along the plate, interacts with the joint and is detected on the other side by a micromachined air-coupled capacitance transducer. Analysis of recorded signals allows to evaluate the condition of the bond.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.315-317
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• 1999

The complications associated with the use of pulmonary artery catheter include dysrhythmias, heart block, pulmonary artery rupture, pulmonary infarction, endocardial damage, balloon rupture, arterial puncture, thromboembolism, air embolism, infection, pneumothorax, and knotting of the catheter. Knotting of the catheter is a rare complication and it should be anticipated if there is an excessive advancement of the pulmonary artery catheter beyond the normally expected distance. We report a successful surgical removal of knotted pulmonary artery catheter by sternotomy and cardiopulmonary bypass.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.813-820
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• 2009

On Dec 22, 1909, a young patriot called Lee Jae-Myung (1986~1910) attempted to assassinate Lee Wan-Yong, the prime minister of the last Yi Choseon cabinet and he later signed the annexation treaty with imperial Japan. Despite that Lee Jae-Myung failed in this assassination attempt, his heroic deed motivated national pride thereafter. After this attempted assassination, a medical record was prepared about stab wound that was inflicted upon Lee Wan-Yong during the trial of Lee Jae-Myung, and this record included many significant specific descriptions that were concerned with thoracic surgery. They included an intercostal stab wound and intercostal arterial hemorrhage, lung injury, chest contusion, traumatic pleuritis and supposedly pneumo-and hemothorax. Thoracentesis for drainage of the serosanguinous pleural effusion was also mentioned. This medical record is judged to be the first written medical record on thoracic surgery in Korean history. The aim of this study is to analyze the content of the record as it is related with a well known episode in modern Korean history.

• Advanced Industrial SCIence
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• v.2 no.3
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• pp.1-7
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• 2023

Recently, it is increasing that a issue of concern about radiation exposure. It affects soil, water, air, crops, etc., and in the long term, environmental pollution and food pollution occur, and it is considered to cause social problems and economic damage. Radiation exposure causes diseases and health problems, but as a method for diagnosing diseases, nuclear medicine tests such as X-ray imaging, CT, and PET-CT are conducted, and radiation isotopes are exposed for the purpose of cancer treatment. A Hungarian case study on radiation in water, particularly drinking water, following the release of radioactive waste from Fukushima, and an examination of the Larsemann Hills area in Antarctica, found that it was within the prescribed radioactivity limits of drinking water recommended by the World Health Organization. We looked at radioprotective agents, focusing on DNA damage, cell and organ damage, and cancer, and also investigated various literatures on ACE inhibitors, antioxidants, and natural substances among restoration materials. Although exposed to radiation in everyday life, the reason why it can be safe is probably because there is a radiation protection material and a recovery material for radiation exposure, so we are trying to find possible materials.