• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.9
• /
• pp.685-697
• /
• 2017

In this paper, it is presented the result of design and fabrication for C-band solid state high power amplifier unit and components using in search radar. The solid state power amplifier(SSPA) assembly was fabricated using GaN(Gallium Nitride), which is semiconductor device, and the transmit signal output power of the solid state high power amplifier unit is generated by combining the transmit signal power of the solid state power amplifier configured in parallel through a design and fabricated waveguide type transmit signal combine assembler. Designed solid state high power amplifier unit demonstrated C-band 500 MHz bandwidth, maximum 10.5% duty cycle, transmit pulse width from $0.0{\mu}s{\sim}000{\mu}s$, and transmit signal power is 44.98 kW(76.53 dBm).

• Asian Oncology Nursing
• /
• v.1 no.2
• /
• pp.204-216
• /
• 2001

The purpose of this study was to test the effects of foot reflexology on pain and mood in patients who have just had a mastectomy. The research design was a nonequivalent control group, non-synchronized design. The participants for this study were 28 patients with breast cancer on first or second day after mastectomy surgery. The first 12 patients were assigned to the control group and the second 16 to the experimental group. The study was conducted from October 28, 2001 to December 22, 2001 on a surgical unit of Y Medical Center in Seoul, Korea. Pain intensity, blood pressure, pulse rate and mood were measured as dependent variables. The instrument used for pain intensity and mood was a 10 cm visual analogue scale. Cronbach alpha for this study was .70. For the experimental group pre and post tests were done immediately before and 15 minutes after completion of foot reflexology. Foot reflexology was performed once for 20 minutes. After the pretest, patients in the control group were instructed to have a quiet time for a 35 minute period and then the post-test was done. The number of participants was small so the data were analyzed by Mann-Whitney U test, and Wilcoxon signed ranks test. The results of this study are as follow : 1. In the experimental group there were significant decreases between the pre and post tests for pain intensity (z=-3.47, p<.001), diastolic blood pressure (z=-2.67, p<.01) and pulse rate (z=-3.44, p<.001) but there was no difference between the two groups on the post test. 2. The systolic blood pressure, diastolic blood pressure and pulse rate were also not significantly different between the experimental group and the control group on the post test. 3. The mood score was significantly improved after foot reflexology(z=-3.52, p=.000) and the difference between the two groups was also significant (u=49.0, p=.03). In conclusion, there was a statistically significant difference in mood between the two groups, but no difference for pain intensity, blood pressure, or pulse rate. However, there were significant differences between the pretest and post-test for pain intensity, diastolic blood pressure and pulse rate in the experimental group. On the basis of the above findings, this study suggests that foot reflexology can be an effective method of relieving pain and improving mood in clinical practice in women who have had mastectomy surgery.

• Korean Journal of Agricultural Science
• /
• v.23 no.1
• /
• pp.39-50
• /
• 1996

The normal cement concrete is widely used material to build the construction recently, but it has a fault to increase the dead load on account of its unit weight is large compared with strength. So, many engineers are continuously searching for new materials of construction to provide greater performance at lower density. Many studies were carried out on the lightweight aggregate concrete in foreign country in the latter half of the 19th century, therefore lightweight aggregate concrete has been used successfully for many years for structural members. The main purpose of the work described in this paper were to establish its physical and mechanical properties of no-fines lightweight concrete using synthetic lightweight coarse aggregates. Test results are summarized as follows ; The water-cement ratio was shown less than 33% in use synthetic lightweight coarse aggregates, unit weights of synthetic lightweight concrete was shown less than $1,800kg/m^3$ and compressive strength was higher than $200kg/m^2$. And the pulse velocity was more than 3,000m/sec. The relationship of compressive strength between unit weight and pulse velocity was shown to be approximately linear.

• Korean Journal of Adult Nursing
• /
• v.13 no.2
• /
• pp.340-349
• /
• 2001

The purpose of this study was to investigate the effect of a hand massage program on anxiety, vital sign and pain in clients with ischemic heart disease. The design utilized for this study was quasi-experimental with a nonequivalent control group non-synchronized design The subjects were fifty-four patients, twenty-eight for the experimental and twenty-six for the control group, who were admitted with ischemic heart diease at a cardiac intensive care unit in K medical center of K university. This study was carried out from May, 1999 to March, 2000. The level of anxiety and pain measured by Visual Analogue Scale, systolic blood pressure, diastolic blood pressure and pulse rate were measured before and after hand massage, the state of Anxiety was measured by the Spielberger (1970) scale at admission and after hand massage for three days. The collected data were processed by using the SPSS PC program and analyzed using $\chi^2$-test and t-test. The result of this study are as follows : 1. The scores of VAS anxiety and State of anxiety of the experimental group were lower than those of the control group. 2. The degree of systolic blood pressure, diastolic blood pressure and pulse rate of the experimental group were lower than that of the control group. 3. The score of VAS pain of the experimental group was lower than that of the control group. The results suggested that hand massage can decrease VAS anxiety, State of anxiety, vital signs and VAS pain of patients who were admitted with ischemic heart disease at cardiac intensive care unit Therefore, it is proposed that hand massage is an appropriate nursing intervention to relieve anxiety of the patients who were admitted with ischemic heart disease at a cardiac intensive care unit.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.3
• /
• pp.115-122
• /
• 1998

For digital engine control timings, such as ignition, are based on the crank shaft angle. Therefore, it is very important that the angle of the crank shaft can be detected with accuracy for optimal ignition timing. Sequential multi-point injection(MPI) systems that have independent injection events for each cylinder, are used to inject an accurate quantity of fuel, and to cope with varying engine status promptly. In this study the distributorless ignition timing. A crankshaft position sensor has been installed such that it generates a number of pulses per crankshaft revolution to permit accurate detection of the crank shaft angle. An event detecting algorithm has been developed, which detects the crank shaft pulses generated by the position sensor, and the software outputs the required control signals at given crank angle values. We clarified that the hardware method is the best way to increase the performance of the control system, because the event detecting duration T(1+2)max becomes zero.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.11
• /
• pp.912-917
• /
• 2001

In this study, we define the measuring method of crank angle precisely using an event and perform a study on the hardware structure and software algorithms which is applicable for the commercial engine. Also we developed a Computer-ECU(Personal computer based electronic control unit) using a computer and a microprocessor, for performing the ignition at a desire position(angle) and for controlling a duty ratio a pulse for ISC(Idle speed control). We applied these algorithms to the modeling which is induced a concept of event and got a better result than a conventional ECU in the state of transient as a result of performing air fuel ratio control in a commercial engine. This technique can be used for the back to improve ECU performance. It the present type of Hybrid I. C voltage regulator is altered to the new type of regulator, we will be surely able to reduce the production cost as well as simplify the design of alternator\`s rear bracket and rectifier part because of the removal of trio diode. Experiment is taken by MS-R004.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.12
• /
• pp.2296-2302
• /
• 2006

In this paper, we propose a development technique of high precision laser finder ranger within instrument distance 1km, instrument error less than 1 m by using pulse time of flight method in the 5m unit instrument and heterodyne method in the within Am unit. These propose methods can be more advanced to measurement velocity and more highly precision distance instrument not affected the strength of light. We also validate this usefulness.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.36 no.4
• /
• pp.48-55
• /
• 1994

This study was performed to evaluate the engineering properties of the lightweight concrete using surlightweight aggregate foaming agent and high performance agent. The following conclusions were drawn. 1. The unit weight of type A, B and C concrete was 0.912t/m$^3$, 1.592t/m$^3$ and 1.070t/m$^3$, respectively. Specially, the unit weight of type A concrete was decreased 42% than that of the type B concrete. 2. The highest engineering property was measured in the lightweight concrete using high performance agent Also, the ratio of tensile and bending strength to compresive streng-th of the lightweight concrete was higher than that of the normal cement concrete. 3. The dynamic modulus of elasticity of the lightweight concrete was in the range of 2.86 x 10 5~9.86 x 10 5 kg/cm$^2$ which was approximately 300% than that of the normal cement concrete. 4. The ultrasonic pulse velocity of the lightweight concrete was in the range 2047~3394 n/sec, which was smaller than that of the normal cement concrete.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.6
• /
• pp.2428-2434
• /
• 2012

This paper describes the control of a solenoid valve of ESC(Electronic Stability Control) with hydraulic modulator in braking system. ESC ECU(Electronic Control Unit) to control the high-frequency control and slope control method was applied, the surge pressure and EMI(electromagnetic interference) reduction characteristics were studied. The stage of ECU output was added the slope shaping function to reduce electromagnetic emission at higher frequencies. Measurements show that this high frequency ECU manages to reduce the surge pressure and electromagnetic emission by the control of solenoid valve. In conclusion, by using the results of this study for the high frequency ECU control, we could expect enhancement of braking system performance.

• Journal of Power Electronics
• /
• v.15 no.6
• /
• pp.1456-1467
• /
• 2015

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.