• 한국항공운항학회지
• /
• 제15권1호
• /
• pp.1-10
• /
• 2007

When detonation is occurred, the working fluid is compressed itself, though there are no other devices that compress the fluid. As a result, an engine which uses detonation for a combustion process doesn't need moving parts so that the engine can be lighter than other engines ever exist, and such an engine is often referred to as a pulse detonation engine. Since using detonation has higher performance than using deflagration, many studies have been attempting to control and analyze the engines using detonation as combustion. The purpose of this study is to analyze the hybrid cycle which is consisted of Brayton and Pulse Detonation Engine cycle. At first, we set the theoretical basis of detonation analysis, and after that we consider two hybrid cycles; a turbojet hybrid cycle and a turbofan hybrid cycle. The more energy released, the higher detonation Mach number the detonation wave has. In general, a cycle which has a detonation process has higher performances but thermal efficiency of hybrid turbofan engine.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
• /
• pp.253-256
• /
• 2002

In this paper, we implement the volume pulse detection system which can quantitatively represent an artery elasticity. The system consists of transducer which has IRLED-photodiode detecter, temperature sensor, filters, preprocessing circuits, A/D converter, serial communication part and computer system. In order to presume the artery elasticity information we measure the volume pulse at four points and then evaluate the transition time, distance and the correlation coefficient of the pulse wave between the points. We test the system with 10 subjects during the week for basic experiment and obtain the data at four points. As the result of experiment, we can detect normalized volume pulse wave and evaluated parameter with effectively.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 E
• /
• pp.1755-1757
• /
• 1998

Pulse transformers have been developed to apply for pulsed power technology as an alternative of a Marx generator. To obtain repetitive pulsed power generation, it is necessary to observe the rising time of output of pulse transformer. In this paper, using the equivalent circuit, The rising wave of output of pulse transformer is simulated for various input wave by using the Electromagnetic transient program(EMTP).

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.1346-1353
• /
• 2009

In this study, a numerical study was carried out to simulate the expansion of ground borehole by pulse discharge technology using finite element analysis. Considering the mortar in the borehole as an acoustic medium and the surrounding soil as an elasto-plastic material, the strong shock wave developed by the pulse discharge was modeled using the underwater explosion model. The ground expansion was simulated based on a coupled acoustic-structural analysis with varying properties of mortar and soil, and the behavior between acoustic-structural interface.

• 한국전기전자재료학회논문지
• /
• 제26권6호
• /
• pp.472-477
• /
• 2013

This paper carried out the comparative analysis on ground impedance of a carbon block and a copper rod. Two types of grounding electrode were compared ; a carbon block (L : 1 m, ${\Phi}$ : 245 mm) buried at a depth of 0.8 m and a three-linked copper rod (L : 1 m, ${\Phi}$ : 10 mm) of equilateral triangles with 1 m spacing. Ground impedance depending on applied current source was evaluated by the application of a sine wave current with 60 Hz ~ 3.5 MHz, a fast-rise pulse with rising time of 200 ns, a standard lightning impulse of $8/20{\mu}s$ and a 600 Hz square wave. Ground impedance for both electrodes were almost the same value below 100 kHz, and increased rapidly afterwards. The maximum ground impedance appeared $400{\Omega}$ at around 1.5 MHz. Ground impedance of the carbon block was lower at the square wave and was higher at fast-rise pulse than that of the copper rod. Also, ground impedance as ages showed no difference for the last 8 months. From the results, it is likely that ground performance for both electrodes shows no difference against commercial frequency and lightning impulse current, while the copper rod shows better performance against a fast-rise pulse with rise-time of a few hundred ns.

• 한국항공우주학회지
• /
• 제33권3호
• /
• pp.99-106
• /
• 2005

액체로켓엔진 개발에서 필수 단계인 연소안정성 확인을 위한 연소안정성 평가시험(stability rating test) 방법의 개발을 위해서는 압력교란장치의 특성과 더불어 안전한 연소시험 절차(sequence)의 확립이 필수적이다. 따라서 본 연구에서는 연소안정성 평가시험을 위해 개발된 펄스건을 액체로켓엔진의 연소시험에 실제로 적용하기 위한 단계로서, 적절한 연소 시험 절차를 개발/검증하고자 하였다. 먼저 펄스건을 실제로 연소실 외벽에 장착하게 되는 압력파 유도장치를 설계하고, 펄스건의 오작동을 방지하기 위한 압력파 유도장치 내부의 냉각시스템의 설계 및 시험을 수행하였다. 이러한 일련의 연소시험 단계를 통하여 실물형 액체로켓엔진에서의 연소안정성 평가시험이 가능한 적절한 시험 단계를 국내 독자적으로 개발하는데 성공하였다.

• 한국전자파학회논문지
• /
• 제30권4호
• /
• pp.307-313
• /
• 2019

Ka-대역 밀리미터파 복합모드 탐색기에 적용할 수 있는 진행파관 증폭기(traveling wave tube amplifier: TWTA)는 고전압생성부(high voltage power supply: HVPS), 변조부(grid modulator), 제어부(command & control), 고조파부(RF assembly)로 구성되는 고출력 펄스형 송신기이다. 펄스 반복 주파수(pulse repetition frequency: PRF)와 전원공급기 스위칭 주파수가 동기/가변되어 -17.9 kV 고전압을 생성하는 고전압 전원 공급기와 RF 펄스 변조를 위한 고속 그리드 스위칭 변조기를 설계하였다. 체적이 3.18 L로 소형화로 제작된 TWTA는 그리드 on/off 신호의 상승/하강시간이 최대 18.5 ns 이하 고속펄스 스위칭 특성을 가지고, 첨두전력은 564.9 W 이상으로 고출력 성능을 보였다. 또한 PRF와 PRF/2 범위 내에서 -68.4 dBc 이하의 우수한 불요파 성능을 확인하였다.

• 척추신경추나의학회지
• /
• 제4권2호
• /
• pp.39-45
• /
• 2009

Objectives : The aim of this study is to compare the improvement of Low back pain (LBP) depending on male Inpatient's Brachlalankle Pulse Wave Velocity (baPWV), Method : We evaluated 35 LBP inpatients who took pulse wave velocity test during admission at Jaseng hospital from November 2008 to september 2009. We used applanation tonometry method to measure pulse wave velocity and numerical rating scale to measure patient's improvement. Result : At admission, standard deviation of normal group's NRS was $7.44{\pm}1.67$ and high risk group's was $7.57{\pm}2.09$(P=0.678). After 5 days of admission, standard deviation of normal group's NRS was $5.67{\pm}1.94$ and high risk group's was $6.00{\pm}2.17$(P=0.680). After 10 days of admission, standard deviation of normal group's NRS was $4.00{\pm}1.80$ and high risk group's was $4.95{\pm}1.96$(P=0.281). After 15 days of admission, standard deviation of normal group's NRS was $2.89{\pm}1.62$ and high risk group's was $4.10{\pm}1.92$(P=0.124). At discharge, standard deviation of normal group's NRS was $5.11{\pm}1.69$ and high risk group's was $4.86{\pm}2.08$(P=0.504). Comparison between admission and discharge, standard deviation of normal group's NRS was $5.11{\pm}1.69$ and high risk group's was $4.86{\pm}2.08$(P=0.504) Conclusion : Low back patients with high Brachialankle Pulse Wave Velocity, showed slower improvement rate compare to patients within normal rate. But statically, had no significance.

• 한국식품과학회지
• /
• 제53권1호
• /
• pp.99-103
• /
• 2021

마이크로웨이브는 식품의 표면을 투과하여 식품 내부를 매우 신속하게 가열할 수 있으므로 식품의 맛, 냄새, 조직감, 영양가 등에 대하여 최소한의 영향을 미치게 된다(Chandrasekaran 등, 2013; Datta 와 Hu, 1992). 본 실험은 이러한 기능이 있는 마이크로파를 이용한 국내에서 생산가능한 허브 5종의 건조에 따른 품질특성에 있어서의 변화를 알아보고자 하였다. 비조사구와 100 Watt와 600 Watt에서 각각 계속적인 가열건조 방법과 Pulse 방법을 이용한 마이크로파 건조방법을 사용하였으며, 실험결과 조직감 유지 및 갈변화 방지에 매우 효과적인 것으로 나타났다. 또한 CW에 의한 건조 보다는 PW를 활용한 방법이 조직감 유지 및 갈변화 방지, 탈수율에 효과적인 것으로 나타났다. 특히 허브의 총균수 사멸에 있어서 마이크로파는 다른 일반가열보다 짧은 시간 내에 미생물의 사멸효과가 있었으며, CW보다 PW가 미생물의 사멸속도가 빠른 것으로 나타났다. 따라서 마이크로파를 이용한 허브의 건조시 낮은 온도에서의 빠른 건조 발생으로 시간적 향상과 물리적 변화를 최대한 억제시키며 미생물의 성장을 억제하는 작용을 하여 허브 특유의 냄새를 보존시키는 작용으로 앞으로 국내산 허브의 건조저장기술에 마이크로파가 다양하게 이용될 수 있을 것이라 기대된다.

• 동의생리병리학회지
• /
• 제28권6호
• /
• pp.662-667
• /
• 2014

The purpose of this clinical study is to develop structured clinical trial protocol and guideline for improvement of safety, useful and effective of pulse diagnosis devices. As a first step, papers on pulse diagnosis and pulse diagnosis devices from 2001 and 2013 were systematically reviewed. In the next step, we have collected the opinions from the specialists, companies, and statistician in pulse diagnosis to evaluate the current condition, the state and problem of domestic clinical trial cases of pulse diagnosis device. And we have to created protocol and case report form (CRF) in regards to site condition and characteristics of pulse diagnosis devices, and showed the guideline of eligibility criteria, operation process, investigation items, evaluation items and so on. This clinical protocol will become a basic information for a researcher in designing or performing a clinical study of pulse diagnosis devices, and be used as a useful material during acquisition of good clinical data. Furthermore, we hope to enhance the invigoration of pulse diagnosis clinical trials and the performance improvement of pulse diagnosis devices.