• Title/Summary/Keyword: pulse cycle

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Effects of Duty Cycle and Pulse Frequency on the Microstructure and Mechanical Properties of TiAlN Coatings (듀티 싸이클 및 펄스 주파수가 TiAlN 코팅막의 미세구조와 기계적 특성에 미치는 영향에 관한 연구)

  • Chun, Sung-Yong;Hwang, Ju Yeon
    • Journal of the Korean Ceramic Society
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    • v.51 no.5
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    • pp.447-452
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    • 2014
  • This paper presents the effects of pulse plasma parameters such as duty cycle and pulse frequency on the properties of TiAlN coatings deposited by asymmetric bipolar pulsed DC magnetron sputtering systems. The results show that, with decreasing duty cycle and increasing pulse frequency, the coating morphology changes from a columnar structure to a dense structure with finer grains. Pulsed sputtered TiAlN coatings showed higher hardness, higher residual stress, and smaller grain sizes than did DC prepared TiAlN coatings. Moreover, residual stress and nanoindentation hardness of pulsed sputtered TiAlN coatings increased with increasing pulse frequency. Meanwhile, the surface roughness decreased continuously with increasing pulsed DC frequency up to 50 kHz.

Study on the Waveform Analysis of Radial Artery Pulse Diagnosis Using Pulse Meter and Analyzer - the Waveform Analysis of Left KWAN Pulse Dignosis - (맥상기를 통한 요골동맥 맥진법의 맥파분석 - 좌관부위 맥파요인을 중심으로 -)

  • Kim, Gyeong-Cheal;Lee, Jeong-Won;Ryu, Kyeong-Ho;Park, Dong-Il;Shin, Woo-Jin;Kang, Hee-Jung
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.23 no.1
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    • pp.186-191
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    • 2009
  • In the study on the waveform analysis of radial artery pulse diagnosis, we need to establish fundaments of contemporary pulse diagnosis research. As we will to do experimental research on the difference of pulse waveform on the radial artery with applied variations of pressure(5 stage-pressure) and measuring position(CHON, KWAN, CHEOG). First of all, in this research, we did the experiment of the study on the waveform analysis of radial artery(left KWAN) pulse dignosis by using 3 dimension pulse meter and analyzer (3D MAC). As a result. we extracted the seven measurement fluents : energy(E), size of cycle(h1), size of reflection cycle(h2), time of reflection cycle(t2), time of contraction (t4), width of cycle(w), area of waveform(A) by the statistically reasonable differences. We expect that the seven measurement fluents contribute to divide the situation through the results of waveform analysis of radial artery.

A Study on the Atomic-Layer Deposition Mechanism and Characteristics of TiN Films Deposited by Cycle-CVD (Cycle-CVD법으로 증착된 TiN 박막의 ALD 증착기구와 특성에 관한 연구)

  • Min, Jae-Sik;Son, Young-Woong;Kang, Won-Gu;Kang, Sang-Won
    • Korean Journal of Materials Research
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    • v.8 no.5
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    • pp.377-382
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    • 1998
  • Atomic layer deposition(ALD) of amorphous TiN films on $SiO_2$ between 17$0^{\circ}C$ and 21O$^{\circ}C$ has been investigated by alternate supply of reactant sources, Ti[N($C_2,H_5,CH_3)_2]_4$ [tetrakis(ethylmethylamminoltitanium: TEMAT] and $NH_3$. Reactant sources were injected into the reactor in the order of TEMAT vapor pulse, Ar gas pulse, $NH_3$. gas pulse and Ar gas pulse. Film thickness per cycle was saturated at around 1.6 monolayer(MU per cycle with sufficient pulse times of reactant sources at 20$0^{\circ}C$. The results suggest that film thickness per cycle could be beyond 1 MLicycie in ALD, which were explained by rechemisorption mechanisms of reactant sources. The ideal linear relationship be¬tween number of cycles and film thickness is confirmed. As a results of surface limited reactions of ALD, step cover¬age was excellent. Particles caused by the gas phase reactions between TEMAT and NH3 were almost free because TEMAT was seperated from $NH_3$ by the Ar pulse. In spite of relatively low substrate temperature, carbon impurity was incorporated below 4 at%.

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Thermodynamic Analysis of Hybrid Engine Cycle of Brayton and Pulse Detonation Engine (브레이튼과 펄스 데토네이션 복합 엔진 사이클의 열역학적 성능 해석)

  • Kim, Geon-Hong;Koo, Ja-Ye
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.15 no.1
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    • pp.1-10
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    • 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.

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A Study on Pulse Diagnosis in Women with Polycystic Ovary Syndrome (PCOS) (Polycystic Ovary Syndrome(PCOS) 환자의 맥 분석 연구)

  • Park, Kyung-Dug;Bae, Ju-Eun;Yoon, Young-Jin
    • The Journal of Korean Obstetrics and Gynecology
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    • v.30 no.4
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    • pp.77-88
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    • 2017
  • Objectives: The purpose of this study is to analyze the characteristics of the pulse energy in women with PCOS (Polycystic ovary syndrome) compared with women who have a regular menstrual cycle. Methods: We analyzed the values of pulse energy on 20 patients with PCOS as an experimental group and 40 patients with regular menstrual cycle as a control group. Control group was divided into 20 women with follicular phase and 20 women with luteal phase respectively. Statistical analysis was performed using SPSS/Win 18.0, one way ANOVA and Tukey HSD. Results: The results were as follows. 1. The mean pulse energy of the Right Chon was significantly increased compared with those of the Left Kwan and the Right Kwan among PCOS group. 2. There were no statistically significant pulse energy among control groups. Conclusions: The pulse energy of Lung is bigger than that of Spleen and Liver in PCOS patients compared with women who have a regular menstrual cycle.

The Cycle Analysis of 4 Valve-type Pulse Tube Refrigerator (4 밸브형 맥동관 냉동기의 사이클 해석)

  • Cho, Kyung-Chul;Lee, Sang-Won;Lim, Young-Hun;Kim, Soo-Yun;Jung, Pyung-Suk
    • Proceedings of the KSME Conference
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    • pp.636-641
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    • 2001
  • In this paper, we constructed four valve type pulse tube refrigerator and found the characteristic of orifice (needle valve) opening for using phase shifter and optimum cycle time - The valve timing was controlled by the digital timers. The experimental results showed the optimum frequence and cycle time at operating conditions. The results showed that the optimum process time existed and the rate was same at each operating frequence. The no- load temperature of the refrigerator was 85K.

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Ag Pulse 도금을 이용한 표면 형상 및 특성 변화에 대한 연구

  • Jeong, Dae-Hui;Kim, Jeong-Su;Jo, Dae-Hyeong;Yu, Bong-Yeong
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.90.1-90.1
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    • 2012
  • 1934년 J. R. Winkler에 의해 처음으로 개발된 pulse current 도금은 연속적인 직류 단속을 이용한 전기도금으로써 종래의 연속적인 직류(direct current) 전기 도금이 가지는 다공성 및 거친 도금 등의 한계를 극복하기 위해 연구되고 있다. 최근 전기 전자 산업의 급속한 발달과 함께 Au, Pd, Rh 등의 귀금속 도금에 있어서 Pulse 도금은 광택, 다공도, 내부 응력, 불순물 및 수소 함유량의 감소와 같은 특성 향상을 가질 수 있으며 기존 DC 전기 도금의 문제점 해결책으로서 많은 연구가 이루어지고 있다. 하지만 현재까지 Pulse 도금의 정확한 기구(mechanism)에 대한 명확한 정립이 되어 있지 않아 모든 도금계에 적용할 수 있는 standard pattern이 없는 실정이다. 본 연구에서는 귀금속 도금 중 Ag pulse 도금에 있어서 Peak current density, duty cycle, time이 Ag 도금의 표면 형상, 두께, 열전도율에 미치는 영향에 대해 연구하였다.

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Crystal Structure, Microstructure and Mechanical Properties of NbN Coatings Deposited by Asymmetric Bipolar Pulsed DC Sputtering

  • Chun, Sung-Yong;Im, Hyun-Ho
    • Journal of the Korean Ceramic Society
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    • v.54 no.1
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    • pp.33-37
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    • 2017
  • Single phase niobium nitride (NbN) coatings were deposited using asymmetric bipolar pulsed dc sputtering by varying pulse frequency and duty cycle of pulsed plasmas. Crystal structure, microstructure, morphology and mechanical properties were examined using XRD, FE-SEM, AFM and nanoindentation. Upon increasing pulse frequencies and decreasing duty cycles, the coating morphology was changed from a pyramidal-shaped columnar structure to a round-shaped dense structure with finer grains. Asymmetric bipolar pulsed dc sputtered NbN coatings deposited at pulse frequency of 25 kHz is characterized by higher hardness up to 17.4 GPa, elastic modulus up to 193.9 GPa, residual compressive stress and a smaller grain size down to 27.5 nm compared with dc sputtered NbN coatings at pulse frequency of 0 kHz. The results suggest that the asymmetric bipolar pulsed dc sputtering technique is very beneficial to reactive deposition of transition-metal nitrides such as NbN coatings.

Diffraction-Limited High-Power Single-Cycle Terahertz Pulse Generation in Prism-Cut LiNbO3 for Precise Terahertz Applications

  • Baek, In Hyung;Kang, Bong Joo;Jeong, Young Uk;Rotermund, Fabian
    • Journal of the Optical Society of Korea
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    • v.18 no.1
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    • pp.60-64
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    • 2014
  • We report the generation of 3.3-mW single-cycle terahertz (THz) pulses at 1-kHz repetition rate via optical rectification in MgO-doped prism-cut stoichiometric LiNbO3. Efficient pulse-front tilting of 800-nm pulses was realized by an optimized single-lens focusing scheme for radially-symmetric propagation of THz beams. In this geometry, nearly-diffraction-limited THz Gaussian beams with electric field strength as high as 350 kV/cm were generated. The pump-to-THz energy conversion efficiency of $1.36{\times}10^{-3}$ and the extremely high signal-to-noise ratio of ~1:15000 achieved are among the best results for 1-kHz single-cycle terahertz pulse generation ever demonstrated in room temperature operation.

Correlation Results of Pulse/Respiration Ratio and Body Composition Analysis (맥솔(脈率)과 체성분(體成分) 분석(分析)의 상관성(相關性) 연구(硏究))

  • Park, Jae-Sung;Park, Young-Bae;Kim, Min-Yong;Park, Young-Jae
    • The Journal of the Society of Korean Medicine Diagnostics
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    • v.10 no.2
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    • pp.132-150
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    • 2006
  • Objectives : The objective is that we measure and analyze Pulse-Respiration Ratio and Body Composition Analysis to study the correlation between both. Methods : First, after subjects take a rest over 10 minutes, we measure their electrocardiogram and respiration pattern through which we take average peak interval to calculate an average pulse cycle and a respiration cycle. An average respiration cycle divided by an average Pulse Rate gives Pulse-Respiration Ratio. Next, we draw out 22 Body Composition Analysis indicators by using In-Body 720 model. Last, we analyze and take statistics on them by using SPSS 13.0 program. Results : Negative is the correlation between P/R Ratio and Body Composition Analysis indicator like fatness degree, body fat volume, body fat rate, abdominal fatness, BMI. Conclusions : 1. The higher P/R Ratio the more likely to be thin, the lower P/R Ratio the more likely to be fat. 2. We separately analyze P/R Ratio depending on each breathing frequency and pulse frequency to find out that breathing frequency has great influence and that breathing frequency decides the fatness degree. 3. In study on the correlation between P/R Ratio and Body Composition Analysis, fatness degree, in-body fat volume, in-body fat rate, BMI are the related indicators, which shows the connection with the fatness indicators. 4. In study on the correlation between Han-Yeol [寒熱] grade and Body Composition Analysis indicators, the result is that Han[寒] has no connection and that only Yeol[熱] grade has something to do with it, which means the higher heat symptom subjects have, the more basic metabolism volume and muscular build they have.

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