• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.528-530
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• 2008

The effect of consolidation temperature on the microstructure, density and mechanical properties (especially, wear property) of $Al_{92.5}-Fe_{2.5}-Cr_{2.5}-Ti_{2.5}$ alloy fabricated by gas atomization and magnetic pulsed compaction was investigated. All consolidated alloys consisted of homogeneously distributed fine-grained fcc-Al matrix and intermetallic compounds. Relative higher mechanical properties in the MPCed specimen were attributed to the retention of the nanostructure in consolidated bulk without cracks. The as consolidated bulk by magnetic pulsed compaction showed the enhanced wear properties than that of a general consolidation process. In addition, the wear mechanism and fracture mode of MPCed bulk was discussed.

• 한국자기학회지
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• 제10권1호
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• pp.30-36
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• 2000

Q switch mode 혹은 Fixed Q mode Nd-YAG 레이저 어블레이션법으로 (100)Si 기판위에 SmCo 박막을 증착하였다. 증착시 Sm$_{100-x}$Co$_{x}$ (73$\leq$x$\leq$93) 조성의 타겟을 사용하였고, 기판온도는 600~$700^{\circ}C$ 변화시켰으며 각 mode 에너지를 조절하였다. Q switching mode로 증착된 박막의 4$\pi$Ms, $_{i}$H$_{c}$ 및 4$\pi$M$_{r}$/4$\pi$M$_{s}$는 각각 5.2~7.7 kG, 190~250 Oe, 0.4~O.74이었다. 반면, Fixed Q mode로 얻어진 박막의 $_{i}$H$_{c}$, 4$\pi$M$_{r}$/4$\pi$M$_{s}$는 각각 430~6290 Oe, 0.32~0.91로 훨씬 양호한 경자기 특성이 나타났다. 후자의 자기특성은 박막에 존재하는 입자(droplet)내 SmCo$_{5}$ 와 Sm$_2$Co$_{17}$상의 생성에 의한 것으로 판단된다. 입자의 존재로 인한 박막표면의 거칠기는 향후 연구에서 해결되어야 할 문제점으로 확인되었다.문제점으로 확인되었다.었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.264-268
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• 2003

This paper describes a high voltage high power DC power supply which has the ability of pulsed mode operation. The power supply Is constructed with several series connected power converters based on modified multilevel converters. The modified multilevel converters are suitable for the protection of frequent output short-circuit. The output dc power of the proposed converter can be disconnected from the load within several hundred microseconds at the instant of short-circuit fault. The rising time of the dc load voltage is as small as several hundred microseconds, and there is no overshoot of the do voltage because the dc output capacitors keep undischarged state. Analysis, simulations, and experiments are carried out to Investigate the operation and usefulness of the proposed scheme.

• Nuclear Engineering and Technology
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• 제2권4호
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• pp.249-254
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• 1970

고 에너지 영역에서 비탄성핵을 가진 충격중성자 전도문제에서 시간과 에너지의 과도적인 특성은 연속 에너지 전도연산자로서 면밀히 해결했다. 점근적으로 가장 우세한 하나의 고정된 시간고유치를 발견했다. 완전한 해는 다음 세 부분으로 되어 있다. 1. 점근적으로 가장 우세한 시간과 에너지의 분리 가능형. 2. 과도적으로 감속하는 순 에너지에 의해서 결정된 분리 불가능형. 3. 점근적으로 무시할 수 있는 시간과 에너지의 혼합에 의하여 결정된 분리 불가능형.

• 산업기술연구
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• 제26권B호
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• pp.173-181
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• 2006

We analyzed systematically particle growth in the pulsed $SiH_4$ plasmas by a numerical method and investigated the effects of pulse modulations (pulse frequencies, duty ratios) on the particle growth. We considered effects of particle charging on the particle growth by coagulation during plasma-on. During plasma-on ($t_{on}$), the particle size distribution in plasma reactor becomes bimodal (small sized and large sized particles groups). During plasma-off ($t_{off}$), there is a single mode of large sized particles which is widely dispersed in the particle size distribution. During plasma on, the large sized particles grows more quickly by fast coagulation between small and large sized particles than during plasma-off. As the pulse frequency decreases, or as the duty ratio increases, $t_{on}$ increases and the large sized particles grow faster. On the basis of these results, the pulsed plasma process can be a good method to suppress efficiently the generation and growth of particles in $SiH_4$ PCVD process. This systematical analysis can be applied to design a pulsed plasma process for the preparation of high quality thin films.

• 한국광학회:학술대회논문집
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• 한국광학회 1997년도 Advance Program of 14th optics andquantum Electronics conference, 1997제14 회 광학 및 양자전자 학술 발표회 논문 요약집
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• pp.76-76
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• 1997

• Journal of Oral Medicine and Pain
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• 제22권2호
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• pp.309-325
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• 1997

In order to set the lasing variables and evaluate, clinically, the therapeutic effects of a pulsed Nd:YAG laser on oral lesion, the author applied the laser energy from a fiberoptic delivered, free running, pulsed Nd:YAG laser (wavelength 1064nm, Pulse duration 120$\mu$sec, fiber diameter 200$\mu$m/320$\mu$m) to 22 cases of oral soft tissue lesions and 6 cases of oral hard tissue lesions. The obtained results were as follows : 1. The effective excision with contact mode and the effective hemostasis of accompanied bleeding with noncontact mode were occurred by lasing on oral soft tissue lesions with fiber diameter of 320$\mu$m under the variables of 2.0~4.0W and 20~50Hz which were controlled into high power/low pulses for excision, low power/high pulses for hemostasis, low power in granulation tissue and high power in fibrous tissue according to therapeutic goals and tissue conditions. 2. About 50% of decreasing effect on hypersensitivity was occurred by lasing with non-contact and contact mode on cervical abrasion which caused dentinal hypersensitivity with fiber diameter of 320$\mu$m under the variables of 0.7 - 1.0W and 10Hz which were applied 2~3 times with 1 week interval. 3. The effective sterilization of infected root canal and lesion of periapical abscess was occurred by lasing with contact and spiral modes on wall of root canal and periapical abscess with fiber diameter of 200$\mu$m of which the tip was placed about 1mm shorter than root canal length under the variables of 1.OW and 10Hz.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.359-362
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• 2012

The results are shown highly unstable mode's detonation dynamics by compared with weakly unstable mode. And we investigate the difference and similar features of 2D and 3D results. By using PSD via FFT, the effects of pre-exponential factor difference and of unstable mode were investigated in this study. The result of PSD is shown pulsed features in weakly unstable mode, but noselike in highly unstable mode. By compared between Sheliren image and overlaid slice image, the irregular feature of detonation waves structure was discussed in highly unstable mode.

• The Journal of Korean Physical Therapy
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• 제26권5호
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• pp.331-343
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• 2014

Purpose: The purpose of this study is to assess the effectiveness of short-wave therapy (SWT) for treatment of knee osteoarthritis (OA) as compared to placebo and control, and to assess the question of whether the effects are related to the mode, dosage, and application method. Methods: We searched randomized, placebo-controlled trials using electronic databases. We also manually reviewed sources in order to identify additional relevant studies. Results: Eight studies (597 participants) with OA were included in the meta-analysis. Pulse SWT had a significant effect on pain relief compared with control treatment, while did not favour compared with the placebo group. Pulse SWT had a significant effect on functional improvement compared with control and placebo treatment. Continuous SWT had no effect on pain relief and functional improvement. Capacitive SWT a significant effect on pain relief, functional improvement, and muscle strength. Continuous and capacitive SWT had increased muscle strength significantly. We found no clinical significance of all outcomes except pain and functional improvement in pulsed SWT with low dose. There was no difference in adverse events. None of the participants experienced any serious adverse events. Conclusion: Low dose pulsed SWT provided a short-term clinical benefit for pain relief and functional improvement. Pulsed SWD with low and high dose had effects on pain and function. There seems to be a placebo effect. We found significant effects on pain and function in capacitive SWT. Despite some positive findings, this analysis lacked data on how effectiveness is affected by mode, dosage, and application method of SWT. Further well-designed clinical studies are required in order to confirm the effectiveness of SWT.

• 접착 및 계면
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• 제10권1호
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• pp.17-22
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• 2009

Polymer thin films were prepared by radio frequency (RF) plasma polymerization of phthalic anhydride (PA). First, monomer vaporization temperature ($100{\sim}160^{\circ}C$) was optimized by evaluating the thermal properties of thin films using differential scanning calorimeter (DSC) and measuring the root-mean-square (RMS) roughness with atomic force microscope (AFM) at the fixed plasma power of 10 W and time of 5 min in a continuous-wave (CW) mode. Plasma power (5~20 W) was then optimized by measuring the film solubility in solvents such as toluene, acetone, dimethylsulfoxide (DMSO) and 1 methylpyrrolidine (NMP). Next, pulsed mode plasma polymerization was also studied by varying the duty cycle of on-time (5, 20%) under optimized conditions of continuous-wave (CW) mode ($120^{\circ}C$, 10 W) in order to increase the anhydride functional groups. Finally, polymer thin films were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA) and ${\alpha}$-step.