• Proceedings of the Korean Society of Life Science Conference
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• 2006.09a
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• pp.39.2-39.2
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• 2006

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.457-460
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• 1997

The photoconductive gain mechanism in various types of hydrogenated amorphous silicon devices, such as p-i-n, n-i-n and n-i-p-i-n structures was investigated in connection with applications to radiation detection. We measured the photoconductive gain in two time scales: one for short pulses of visible light $(<1{\mu}sec)$ which simulate the transit of energetic charged particles, and the other for rather long pulses of light $(\sim1msec)$ which simulate x-ray exposure in medical imaging. We used two definitions of photoconductive gain: current gain and charge gain which is an integration of the current gain. We found typical charge gains of $3\sim9$ for short pulses and a few hundred for long pulses at a dark current density level of $10mA/cm^2$.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2000.01a
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• pp.38-40
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• 2000

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2000.01a
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• pp.44-46
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• 2000

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.1
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• pp.23-26
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• 2009

During operations, neurosurgeons usually perform multiple temporary occlusions of parental artery, possibly resulting in the neuronal damage. It is generally thought that neuronal damage by cerebral ischemia is associated with extracellular concentrations of the excitatory amino acids. In this study, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion(VO) model to compare between single occlusion and repeated transient occlusions within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flowmetry simultaneously with cortical glutamate level measured by amperometric biosensor. From real time monitoring of glutamate release in 11 VO model, the change of extracellular glutamate level in repeated transient occlusion group was smaller than that of single occlusion group, and the onset time of glutamate release in the second ischemic episode of repeated occlusion group was delayed compared to the first ischemic episode which was similar to that of single 10 min ischemic episode. These results suggested that repeated transient occlusion induces less glutamate release from neuronal cell than single occlusion, and the delayed onset time of glutamate release is attributed to endogeneous protective mechanism of ischemic tolerance.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.271-278
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• 2009

Recently, robot research and development was interesting the inside and outside of the country. Medical robot surgery showed diverse advantages according to advanced technical robot research. Also the academic society, research institute and industry showed concerning to the medical robot system. There is a growing need to introduce medical research for aging society. The surgical landscape is quickly changing because of the major driving force of robotics. Robot system and biomedical engineering research as defined a new engine of development show present ways of future revitalization of medical robot system. Medical robot system will be even more utilized when we keeps trying to combine high biomedical technique, IT research, and robot technique. In this review article, we begin with a short historical review of medical robotics, followed by an overview of clinical applications where robots have been applied.

• Journal of Biomedical Engineering Research
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• v.39 no.6
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• pp.268-277
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• 2018

With drastic change in the market and technology of medical devices, a comparative analysis is necessary in advanced systems internationally in order to prepare domestically applicable plans for improvement in classification and differential grade management for items of medical devices. This research examines and analyzes the differences of definition and legal systems of medical devices among Korea, United States, EU, Japan and China, and investigates classification and grading system of each country to identify disadvantages of classification and grading structures for medical device in Korea. This research suggests ways to supplement the disadvantages of domestic classification and grading system of medical devices, and elicits differential management plans for medical devices.

• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.206-214
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• 2019

Surgical methods and associated precision systems have been developed, but surgical procedures that require precise location and fine manipulation of the lesion remain a limitation. The combination of precision robot manipulation technology and 3D medical image navigation technology overcomes the limitations of minimally invasive surgery (MIS) and enables a more stable and successful operation. Surgical robots are surgical robots such as da Vince, and surgical robots using industrial robotic arms. There are various developments and researches of medical robots. In recent medical robot development, a new type of surgical robot based on an industrial robot arm capable of easily replacing the end effector according to the user's needs is being actively developed at home and abroad. Therefore, in this study, we developed safety and performance evaluation guideline for micro - surgical robots based on open robot platform using general purpose robot arm to help quality control of the medical device.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.219-230
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• 2018

The present study examined a moving bed biofilm reactor (MBBR) bioreactor on a laboratory scale for simultaneous removal of atrazine, organic carbon, and nutrients from wastewater. The maximum removal efficiency of atrazine, chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN) were 83.57%, 90.36%, 90.74% and 87.93 respectively. Increasing salinity up to 40 g/L NaCl in influent flow could inhibit atrazine biodegradation process strongly in the MBBR reactor.Results showed that MBBR is so suitable process for efficiently biodegrading of atrazine and nitrogen removal process was based on the simultaneous nitrification-denitrification (SND) process.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.147-149
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• 2003

Using computational fluid dynamics with the fluid-structure interaction, structural effects of intra-luminal thrombus were determined in thrombosed axisymmetric abdominal aorta aneurysm (AAA) models under pulsatile flow. Four different models, varying dilatations of the aneurysm and Young's moduli of intra-luminal thrombus, were defmed. Compared with unthrombosed AAA models, both von Mises stress and radial displacements in the aneurysm wall significantly decreased. Stiffer intra-luminal thrombus reduced von Mises stress in the aneUtysm wall. The present study supported that intra-luminal thrombus might reduce wall stress in the aneurysm.