• Food Science of Animal Resources
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• v.35 no.6
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• pp.800-806
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• 2015

We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 µs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorganisms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (p<0.05). These results indicate that a relatively low electric-field strength of 10 kV/cm can be used to pasteurize low-fat milk.

• The Journal of Korean Medicine
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• v.30 no.3
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• pp.98-105
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• 2009

Objective: Increased aortic and carotid arterial augmentation index (AI) is associated with the risk of cardiovascular disease. The most widely used approach for determining central arterial AI is by calculating the aortic pressure waveform from radial arterial waveforms using a transfer function. But how the change of waveform by applied pressure and the pattern of the change rely on subject's characteristics has not been recognized. In this study, we use a new method for measuring radial waveform and observe the change of waveform and the deviation of radial AI in the same position by applied pressure. Method: Forty-six non-patient volunteers (31 men and 15 women, age range 21-58 years) were enrolled for this study. Informed consent in a form approved by the institutional review board was obtained in all subjects. Blood pressure was measured on the left upper arm using an oscillometric method, radial pressure waves were recorded with the use of an improved automated tonometry device. DMP-3000(DAEYOMEDI Co., Ltd. Ansan, Korea) has robotics mechanism to scan and trace automatically. For each subject, we performed the procedure 5 times for each applied pressure level. We could thus obtain 5 different radial pulse waveforms for the same person's same position at different applied pressures. All these processes were repeated twice for test reproducibility. Result: Aortic AI, peripheral AI and radial AI were higher in women than in men (P<0.01), radial AI strongly correlated with aortic AI, and radial AI was consistently approximately 39% higher than aortic AI. Relationship between representative radial AI of DMP-3000 and peripheral AI of SphygmoCor had strongly correlation. And there were three patterns in change of pulse waveform. Conclusion: In this study, it is revealed the new device was sufficient to measure how radial AI and radial waveform from the same person at the same time change under applied pressure and it had inverse-proportion to applied pressure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.12
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• pp.1227-1236
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• 2012

The low speed machinery faults are usually caused by the bearing failure of the rolling elements. As the life time of the bearing is limited, the condition monitoring of bearing is very important to maintain the continuous operation without failures. A few monitoring techniques using time domain, frequency domain and fuzzy neural network vibration analysis are introduced to detect and diagnose the faults of the low speed machinery. This paper presents a method of fault detection for the rolling element bearing in the low speed machinery using the Wiener filtering and shock pulse counting techniques. Wiener filter is used for noise cancellation and it clearly makes the shock pulse emerge from the time signal with the high level of noise. The shock pulse counting is used to determine the various faults obviously from the shock signal with transient pulses not related with the bearing fault. Machine fault simulator is used for the experimental measurement in order to verify this technique is the powerful tool for the low speed machine compared with the frequency analysis. The test results show that the method proposed is very effective parameter even for the signal with high contaminated noise, speed variation and very low energy. The presented method shows the optimal tool for the condition monitoring purpose to detect the various bearing fault with high accuracy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1121-1129
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• 2009

In this paper, the UWB(Ultra-Wide Band) modules such as a pulse generator and the LNA(Low-Noise Amplifier) with AGC(Auto Gain Control) are designed to construct a cross-borehole pulse radar system, of which performance is compared with the existing system. The budget and specification of the radar system are determined by calculating the total path loss of the underground medium including an empty cavity. The pulse generator is fabricated to have the repeatation frequency 40 kHz, the pulse width lower than 5 ns and the peak signal level +73 dBm. The UWB LNA is designed to have the noise figure 3.77 dB, the variable gain range 100 dB and the frequency range of 20 MHz to 200 MHz. Compared with the existing system in an actual test site, the implemented system renders it possible to detect the blind area due to the UWB LNA with low noise figure.

• Journal of Internet of Things and Convergence
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• v.9 no.3
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• pp.61-67
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• 2023

In order to optimize the pulse electroforming copper process, a double hidden layer BP (Back Propagation) neural network is constructed. Through sample training, the mapping relationship between electroforming copper process conditions and target properties is accurately established, and the prediction of microhardness and tensile strength of the electroforming layer in the pulse electroforming copper process is realized. The predicted results are verified by electrodeposition copper test in copper pyrophosphate solution system with pulse power supply. The results show that the microhardness and tensile strength of copper layer predicted by "3-4-3-2" structure double hidden layer neural network are very close to the experimental values, and the relative error is less than 2.32%. In the parameter range, the microhardness of copper layer is between 100.3~205.6MPa and the tensile strength is between 112~485MPa.When the microhardness and tensile strength are optimal,the corresponding process conditions are as follows: current density is 2A-dm-2, pulse frequency is 2KHz and pulse duty cycle is 10%.

• Journal of Auto-vehicle Safety Association
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• v.5 no.2
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• pp.5-10
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• 2013

The pole side crash caused fatal injury by comparison with other crash impact mode such as frontal and rear crash. EuroNCAP proposed the pole side crash test using WorldSID(World Side Impact Dummy). The objective of this study is to develop the pole side impact sled test using dummy rib deflection between crash and sled test. In the pursuit of this purpose, we fabricated new pole side sled buck and test preliminary pole sled using ES-2re. Through this, we found the sled acceleration pulse scale. Hardness and thickness of the EPP affects the rib deflection. We conducted the pole sled test using WorldSID based on the preliminary results. As a result, rib deflection was shown to correlate well between crash test and pole side sled test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.673-680
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• 2019

This study was conducted to investigate the effects of plasma homocysteine concentration on the brachial-ankle pulse wave velocity between the normal homocysteine group and the asymptomatic high homocysteine group. 435 subjects who visited the general health examination center from April 1 to October 31, 2016, as well as to compare the direct correlation of the brachial-ankle pulse wave velocity, which indirectly reflects the homocysteine test and arterial stiffness, as a predictor of future cardiovascular outcome. As a result of the study, age, waist circumference, BUN, and plasma creatinine were significantly higher, and HDL was significantly lower in the high homocysteine group (> $15{\mu}mol/L$) than in the normal homocysteine group (< $15{\mu}mol/L$) (p=0.05). In addition, homocysteinemia was associated with smoking and drinking (p<0.001) and was significantly higher in males (p<0.001). The right and left brachial-to-ankle pulse wave velocities were significantly higher in the high homocysteine group (right p<0.001, left p=0.003) before calibrating the relevant variables. There was no significant difference between right and left brachial-to-ankle pulse wave velocities after calibrating the relevant variables. Therefore, further studies on the independent association of lowering homocysteine concentration and prevention of cardiovascular disease and the relationship between homocysteine and renal function are needed.

• Research in Community and Public Health Nursing
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• v.6 no.1
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• pp.98-113
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• 1995

The purpose of this study were two fold : first, to determine the effect of aerobic exercise on BP, pulse rate, body fat, body weight, symptoms of sterss response: and secondly, to apply the aerobic exercise on nursing practice in the healthy or ill subjects. In an attempt to investigate the physiological and psychological effect of exercise, a quasi -experiment, non-equivalent control group pre-test & post-test design was planned. Experiments were carried out from July 4, through August 30, 1994 with 37 subjects conveniently sampled from K & Y sports center located in Taejon. The 37 research subjects were assigned to experimental(16 subjects) and control(21 subjects) groups. Aerobic exercise was carried out for experimental group from three times to five times a week for 6 weeks in aerobic center. Data were analyzed with t-test, mean, per centage of change using SAS program. Results were obtained as follows: 1) Systolic blood pressure (M=123.75mmHg, % of change=1.12%) and diastolic blood pressure (M=74.38mmHg, % of change=5.79%) was increased on that of experimental group after 6 weeks experiment. But there was no significant difference between experimental group and control group. 2) Body weight was decreased on that of experimental group(M=56.54Kg, % of change=-1.60%) and that of control group(M=52.05, % of change=-0.99%) after 6 weeks. But there was no significant difference between experimental group and control group. 3) Body fat was decreased on that of experimental group(M=30.53%, % of change=-3.60%) and that of control group (M=28.75%, % of change=-3.52%) after 6 weeks. There was no significant difference between experimental group and control group. 4) Pulse rate was decreased on that of experimental group(M=69.19회/min, % of change -8.43%) and that of control group(M=76.0회/min, % change -0.07%) after 6weeks. There was significant difference(t=-2.621, P<0.05) between experimental group and control group. 5) Symptoms of stress response were decreased on that of experimental group(M=0.97) and that of control group(M=1.15) after 6 weeks. There was no significant difference between experimental group and control group. Therefore, adherence to aerobic exercise for 6 week seem to be affected mainly pulse rate of subjects. A futher study is necessary to determine the difference in the effect of variety exercise, programs, to study over 6 weeks, to produce professional educational program for exercise speciality nurses.

• Journal of Korean Academy of Nursing
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• v.28 no.4
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• pp.980-991
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• 1998

The purpose of this study was to examnin the effect of slow stroke back massage(SSBM) on anxiety and immune response in patients undergoing open heart surgery and to compare the effect of 5-minutes with 10-minutes SSBM. Among the sixty-four patient subjects, twenty-one were one experimental group receiving massage for 10-minutes, twenty for the other experimental group receiving massage for 5-minutes and twenty-three for the control group. Subjects were admitted at Hospitals in Inchon and Puchon for open heart surgery. This study was carried out from October 10, 1997 to May 10, 1998. The levels of anxiety were measured by the Visual Analogue Scale(VAS), Trait anxiety scale, systolic and diastolic blood pressure, pulse rate, blood cortisol and the levels of immune response were measured by the blood T-lymphocyte and Natural killer cell. Study measurements were taken before and after SSBM on the 1st post operative day. Data were analyzed using x$^2$ test, oneway ANOVA, paired t-test, t-test and Pearson product moment correlation. The results were summarized as follows : 1. After SSBM, VAS anxiety level, systolic and diastolic blood pressure and pulse rate of the experimental group were decreased significantly than those measurements before the SSBM. After SSBM, significant difference in the VAS anxiety level, systolic blood pressure and pulse rate between the experimental and control groups were found. 2. After SSBM, the blood cortisol of the experimental and control groups were increased significantly compared with before SSBM. But the significant difference in blood cortisol between the two groups was not found. 3. After SSBM, the blood T-lymphocyte percentages of the experimental and control groups were decreased signigicantly and blood Natural killer cell percentages of the two groups were increased compared with before SSBM. But significant difference in blood T-lymphocyte and Natural killer cell percentages between the two groups was not found. 4. Significant difference in VAS anxiety level, systolic and diastolic blood pressure, pulse rate, blood cortisol, blood T-lymphocyte and Natural killer cell percentages between SSBM for 5 minutes and SSBM for 10 minutes were not found. Based upon the results, this study concludes that the slow stroke back massage for 5 minutes is a useful intervention that decreases anxiety and produces relaxation in patients undergoing open heart surgery.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.4
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• pp.394-402
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• 2013

This paper presents design, fabrication and ruggedness test of switching-mode power amplifier using GaN(Gallium Nitride) HEMT(High Electron Mobility Transistor) for S-band radar applications. The power amplifier is designed to Class-F for high efficiency. The input signal for the measurement of the power amplifier is pulse signal at $100{\mu}s$ pulse width and duty cycle of 10 %. The measurement results of the fabricated Class-F power amplifier are a power gain of 10.8 dB, an output power of 40.8 dBm, a power added efficiency(PAE) of 54.2 %, and a drain efficiency of 62.6 %, at the center frequency. We proposed reliability test set-up of a power amplifier for ruggedness test. And we measured output power and efficiency according to VSWR(Voltage Standing Wave Ratio) variation. The designed power amplifier achieved output power of 32.6~41.1 dBm and drain efficiency of 23.4~63 % by changing VSWR, respectively.