• Journal of Magnetics
• /
• v.8 no.4
• /
• pp.164-168
• /
• 2003

In high density recording system, the recording head field on a medium should be focused in small bit area and should have a sufficient value to overcome the medium coercivity, which resulted in head saturation. In this paper, an efficient method to access the head field and field gradient considering head saturation is presented. The magnetic vector potential on the head surface is pre-calculated considering head saturation in several cases and accumulated into database. The head field on the recording media is easily produced solving Laplace equation using accessed magnetic vector potential boundaries. The computed head field is compared with a quantified magnetic force microscopy measurement.

• Child Health Nursing Research
• /
• v.18 no.4
• /
• pp.201-206
• /
• 2012

Purpose: In this study changes were observed in body temperature, heart rate and arterial oxygen saturation (SaO2) of newborns after bathing and to determine the effects of covering their heads with cotton hats after bathing. Methods: Participants were 58 newborn infants, 31 in the experimental group had their heads covered with cotton hats after their bath while 27 in the control group did not. Body temperature, arterial oxygen saturation and heart rate were measured at 8 consecutive times after bathing. Data were analyzed using t-test and repeated measures ANOVA. Results: Body temperature declined shortly after bathing. The experimental group showed faster recovery (p<.001). Heart rate increased after bathing in both groups. Heart rate in the experimental group decreased for 120 minutes and gradually increased to baseline (p<.001). In the control group, heart rate decreased for 180 minutes and then increased but did not reach the baseline (p<.001). Arterial oxygen saturation decreased shortly after bathing and recovery to the baseline was more rapid in the experimental group (30 minutes vs. 60 minutes) (p<.001). Conclusion: With significant changes observed in newborns' body temperature, arterial oxygen saturation and heart rate, covering the head right after bathing is effective in stabilizing infants' physiological system.

• Journal of the Korean Geotechnical Society
• /
• v.24 no.3
• /
• pp.53-63
• /
• 2008

The aim of this study was to validate the suitability of an digital image analysis (DIA) method to measure the degree of saturation in the unsaturated conditions. This study was carried out on the Joo-Mun-Jin standard sand. A one-dimensional sand column test was used in the constant water level condition to get the correlation equation between the color number ($C_n$) and the measured degree of saturation (5). In addition, the hanging wale. column technique to determine the soil-water charactenstic curve (SWCC) was performed in a Buchner funnel. The average degree of saturation ($S_{ave}$) in the SWCC could be obtained by substituting average color number at each suction head value with the $C_n\;-\;S$ correlation equation. Comparisons were made between the measured results by the hanging water column test and those obtained from DIA method. Results showed that the DIA method tested here provided fairly good saturation distribution values in the drying and wetting processes.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.31 no.1
• /
• pp.31-34
• /
• 2020

Tracheostomy is considered as a first treatment, when oral intubation seems to be difficult in patient who present severe upper airway obstruction. Generally, tracheostomy is performed in supine position. But if airway obstruction is severe enough to cause dyspnea, low oxygen saturation and inability to maintain supine position, tracheostomy should be performed in sitting position. The authors report a case of successful tracheostomy using high flow nasal cannula which help to maintain stable oxygen saturation and respiration in patients with laryngeal cancer.

• Journal of Biosystems Engineering
• /
• v.27 no.4
• /
• pp.327-334
• /
• 2002

In this study, energy conversion from thermal energy to mechanical power by using n-pentane was tested and exergy variation, cycle number, water quantity pumped and thermal efficiency were analyzed. The energy conversion was done and the water head could be ten meters on the experimental conditions. The operating temperature range of cycle was recommended to be around the liquid-vapour saturation temperature of the working fluid on the viewpoint of the maximum work. The cycle diagram was analyzed by the exergy analysis. For the constant water head, the cycle number was decreased and the water quantity per day was increased and thermal efficiency become higher when the water quantity per cycle become increasing. For the constant pumping water quantity per cycle, cycle number and the water quantity per day was decreased and the thermal efficiency become higher because the saturation temperature become higher when the water head become higher.

• Design & Manufacturing
• /
• v.13 no.2
• /
• pp.37-43
• /
• 2019

This study conducted a research as to condensation heat transfer friction loss headby using three types of flat micro multi-channel tubes with different processing of micro-fin and number of channels inside the pipes and different sizes of appearances. In addition, identical studies were conducted by using smoothing circular tubes with 5mm external diameter to study heat enhancement factor and pressure drop penalty factor. 1) The friction head loss showed an increase as the vapor quality and mass flux increased. In case of saturation temperature, it shows an increase as it gets lower. These factors are the reason occurring as the lower the saturation temperature is, the higher the density of refrigerant vapor gets. The influence of heat flux is similar as the dryness is low, but as it gets higher, it lowers in heat flux, and as the high temperature of high heat flux, it is a factor that occurs as the density gets lower. 2) RMS error of the in case of friction head loss, it showed to be predicted as 0.45~0.67 by Chisholm, Friedel, Lockhart and Martinelli. 3) As forfriction head loss penalty factor, the smaller the aspect ratio is, the larger the penalty factor gets, and as for the effect of micro-fin, the penalty factor increased because it decreases to the gas fluid the way groove for the refrigerant's flow.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.760-765
• /
• 2000

The study deals with the development of a computational procedure for evaluating the temperature rise in dry and lubricated multi-layered contacts of head/disk interface. A transient computational model with a transformed rectangular computational domain is utilized. A model and a computational method for micro-contact with sub-lubricated zone, including friction heat generation, have been presented. The model was applied, taking full account of the changes in contact area and contact load due to frictional heating. The computational distribution of temperature is obtained with the analytical findings for various composition and contact conditions. Especially, a rapid rise ($220^{\circ}C$ or above) in read head temperature lese to a saturation in the influence of a thermal spike on signal performance. This general class of problems can be treated provided that heat generation distribution and layer properties are known.

• Journal of the Korean Magnetics Society
• /
• v.5 no.4
• /
• pp.299-303
• /
• 1995

In order to improve the read-out signal waveform, a shielded magnetoresistive (SMR) head has been designed and studied by applying the transmission-line model. The bias and signal field distribution, the voltage output, the harmonic output signal and resistance value of MR element are simulated as functions of bias current and recording displacement. The results show that the SMR head has good linear character with respect to the medium recording signal in high recording frequency of about 2.5 MHz. The amplitude and waveform of reroduction signal have been obviously improved. The saturation effect on the symmetry and amplitude of reproducing output have also been analyzed.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2002.12a
• /
• pp.214-215
• /
• 2002

High saturation magnetization (B$\_$s/) and excellent high frequency characteristics of magnetic thin films has been recognized as the most important requirement for further miniaturization and higher frequency operation in magnetic devices, such as magnetic heads and magnetic sensors. Up to now, Fe-X-N (X =Ti, Hf, and Al etc.) films with B$\_$s/ of 15 ∼ 19 kG and coercivity (H$\_$c/) of 0.5 ∼ 5.0 Oe have been successfully fabricated and proven to satisfy various requirements as a potential candidate for thin film head materials. (omitted)

• Korean Journal of Metals and Materials
• /
• v.50 no.3
• /
• pp.248-255
• /
• 2012

AlN thin films containing various amounts of Co, AlN-Co, and Al-Co alloy particles were prepared using a two-facing-target type dc reactive sputtering (TFTS) system. The as-deposited films exhibited the variable nature expected from an AlN-rich phase, and an amorphous-like phase, depending on the Co content in the films. Specific favorable microstructures were prepared by optimizing annealing conditions. Those microstructures and their magnetic properties and resistivity were investigated. As-deposited films showed very small saturation magnetization and an amorphous-like structure. However, when annealed, the as-deposited amorphous-like phase decomposes into phases of AlN, Co and Al-Co. These annealing induced changes in the microstructure improve the magnetization and resistivity of the films. Further improvement of soft magnetic properties could lead to the material being used for high density magnetic recording head material.