• Clinical and Experimental Reproductive Medicine
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• v.11 no.2
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• pp.69-76
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• 1984

In order to obtain high proportion of Y sperm the semen was laid over 6%,10% and 20% bovine serum albumin. Separated sperm were stained with quinacrine mustard in order to see F - body which could be seen in human Y sperm. But we could'nt find F-body in the bull sperm. So sperm were compared with size of sperm head. As a result of observation separated sperm was small in size of length and width of sperm head as compared with control sperm. So it was found that the proportion of Y sperm showed a marked increase in separated layer. Then the higher albumin density was, the higher the proportion of Y sperm which had smaller head and faster motility was. But the higher albumin density was, the lower the recovery rate of sperm was. So it was hard to separate Y sperm in oligospermia.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.275-276
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• 2002

Active-head sliders with a unimorph piezoelectric actuator for flying height control were experimentally evaluated. It was found that the normalized stroke of the actuator is 5.2 to 6 nm/V/mm without flying over the disk. However, the normalized adjustment range of flying height is about 1.6 nm/V/mm when the active-head slider is flying over the disk. This value is smaller than the measured value when the slider is not flying, because of the air pressure generated at the active pad when the pad approaches the disk surface.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.9
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• pp.116-125
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• 2008

Inkjet printing technology with a drop-on-demand (DOD) inkget head technology has been recognized as one of versatile and low cost manufacturing tools in the electronics industry. Concerned with control of driving signal, however, general strategy to optimize jetting stability has not been understood well, because of the inherent complex multi-physics nature in inkjet phenomena. Motivated by this, present study investigates the effect of driving waveforms of piezoelectric head on jetting characteristics of DOD inkjet system focused on jetting stability with phase matching of pressure waves in the print head. The results show that velocities and volumes of the ink jetted droplets were linear relations with the driving signal's maximum voltage, while periodic behaviors are observed with the driving signal's pulse widths.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1444-1449
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• 2007

Inkjet printing technology with a drop-on-demand (DOD) inkjet head technology has been recognized as one of versatile and low cost manufacturing tools in the electronics industry. Concerned with control of driving signal, however, general strategy to optimize jetting stability has not been understood well, because of the inherent complex multi-physics nature in inkjet phenomena. Motivated by this, present study investigates the effect of driving waveforms of piezoelectric head on jetting characteristics of DOD inkjet system focused on jetting stability with phase matching of pressure waves in the print head. The results show that velocities and volumes of the ink jetted droplets were linear relations with the driving signal's maximum voltage, while periodic behaviors are observed with the driving signal's pulse widths.

• Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.258-262
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• 2002

Effects of Escherichia coli genomic DNA on the production of phagocyte activating supernatants by the head kidney leucocytes isolated from olive flounder (Paralichthys olivaceus) were investigated. Phagocyte activating activity of the supernatants was estimated by. measuring reactive oxygen species (ROS) production in target head kidney phagocytes. All supernatants from olive flounder head kidney leucocytes-stimulated with E. coli DNA induced significantly (P<0.01) higher ROS production from target pagocytes than the unstimulated control supernatant. Maximum enhancement of chemiluminescent response was observed $5.0-10.0{\mu}g\;mL^{-1}$ of bacterial DNA while the increment ability was decreased significantly (P<0.01) at the concentration of $20.0{\mu}mL^{-1}$. The results demonstrate that olive flounder head-kidney leucocytes stimulated with bacterial DNA release a soluble phagocyte activating cytokines capable of enhancing the respiratory burst activity from target phagocytes.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1107-1108
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• 2008

The purpose of this study is to develope a computer mouse using the head movements and eye blink in order to help the disability persons who can't move the hands or foot because of car accident or cerebral apoplexy. The mouse is composed of two gyro-sensors and photo sensor. The gryo-sensors detect the head horizontal and vertical angular velocities, respectively. The photo sensor detect the eye blink to perform click, double click, and to reset the head position. In the results, we could control the mouse points in real time using the proposed system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.3
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• pp.35-40
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• 2011

5-axis laser cutting has great advantages when it is applied to three dimensional machining requiring high cutting quality. For developing 5-axis CNC laser cutting systems, however, many problems such as rotating a laser head or a working table, 5-axis servo-control mechanism, tool path generation and post-processing, and collision avoidance between a laser head and a work-piece should be solved. In this paper, we deal with developing a motion simulator for 5-axis laser cutting machine with a nutating cutting head whose rotational axis is in an inclined plane. Two essential modules such as post-processor and cutting motion simulator was developed based on a commercial 3D CAD of UG-NX. The developed system was applied to three dimensional cutting products and showed the validity of the developed methods.

• Korean Journal of Head & Neck Oncology
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• v.14 no.1
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• pp.35-39
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• 1998

Objectives: Minimal improvement in the long-term survival of head and neck cancer(HNC) patients has occurred despite a multitude of advances in the control of loco regional disease and a second primary malignancy(SPM) contribute to the continued poor prognosis for the HNC patients. This study was performed in order to identify the clinical characteristics of SPM in the HNC patients. Materials and Methods: The medical records of 354 patients of head and neck squamous cell carcinoma that were followed up after initial treatment during the period of 1987 through 1994 were reviewed. This study examines the medical records of 354 patients with squamous cell carcinoma of the head and neck, of whom 26 subsequently developed a second neoplasm. Results: The actuarial SPM rate was 7.3%, and median time to presentation for the SPM was 26.8 months. The SPM were more likely to occur in male patients who had oral cavity index tumors. Patient whose index tumor was small at diagnosis had a greater chance of developing a second tumor as did those with no cervical lymph node metastases to the neck. Initial treatment modality was not associated with an increased risk of developing a second tumor. The commonest sites for the SPM were the lung and other head and neck area. The 3-year survival for patients who developed a secondary tumor from the time of its diagnosis was 27.8%. Conclusion: The SPM in the head and neck cancer patients are not uncommon and early detection of the SPM will contribute to increase the long-term survival of HNC patients.

• Journal of the HCI Society of Korea
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• v.5 no.2
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• pp.1-6
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• 2010

In this research, we designed the head mouse system for disabled and gamers, a mouse controller which can be controlled by head movements and eye blinks only, and compared its performance with other regular mouse controller systems. The head mouse was moved by a gyro-sensor, which can measure an angular rotation of a head movement, and the eye blink was used as a clicking event of the mouse system. Accumulated errors caused by integral, which was a problem that previous head mouse system had, were removed periodically, and treated as dead zones in the non-linear relative point graph, and direct mouse point control was possible using its moving distance and acceleration calculation. We used the active light sources to minimize the influence of the ambient light changes, so that the head mouse was not affected by the change in external light source. In a comparison between the head mouse and the gazing tracking mouse (Quick Glance), the above method resulted about 21% higher score on the clicking event experiment called "20 clicks", about 25% higher on the dasher experiment, and about 37% higher on on-screen keyboard test respectively, which concludes that the proposed head mouse has better performance than the standard mouse system.

• Journal of Korean Clinical Nursing Research
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• v.17 no.2
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• pp.275-285
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• 2011

Purpose: Head-up position during sleep is one of the non-pharmacologic interventions for the treatment of orthostatic hypotension. Because the head-up position causes discomfort in many patients, this approach may not be acceptable to all patients. We compared the systolic blood pressure in erect position, orthostatic hypotension, orthostatic disability score, and the improvement rates of orthostatic hypotension between the 20 cm head-up group and the 10 cm head-up group. Methods: A control pre/post-test design was used. Between August 1, 2009 and November 15, 2010, we consecutively enrolled patients who showed orthostatic hypotension in patients with Parkinsonian disorders. Sixty-seven patients were prospectively enrolled and forty-four patients were completed the study. Results: There were no statistically significant differences found in the systolic blood pressure in erect position, orthostatic hypotension, and orthostatic disability scores between the two groups. However, five patients showed improvement in 20 cm head-up group and one patient was showed improvement in 10 cm head-up Group. Conclusion: Orthostatic hypotension is decreased with 20 cm head-up position in some patients with Parkinsonian disorders (p=.034). Further research investigating the relationships between orthostatic hypotension and head-up position are warranted.