• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제20회 춘계학술대회 논문집
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• pp.49-53
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• 2003

In this study, the geometric design parameters of ejector system were investigated. The critical parameters were primary nozzle area ratio, 2nd-throat cross sectional area and 2nd-throat L/D ratio. At every geometry cases, primary pressure and secondary pressure were measured simultaneously according to secondary mass flow rate. From the results, the ejector starting pressure, unstarting pressure and minimum secondary flow pressure were found and we got the effect of geometric parameters to ejector performance and the way to optimal design of ejector system for chemical lasers operating. Also the experiments of changing secondary flow temperature were carried out.

• 한국레이저가공학회지
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• 제14권4호
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• pp.14-20
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• 2011

The advantage of using lasers for through silicon via (TSV) drilling is that they allow higher flexibility during manufacturing because vacuums, lithography, and masks are not required; furthermore, the lasers can be applied to metal and dielectric layers other than silicon. However, conventional nanosecond lasers have disadvantages including that they can cause heat affection around the target area. In contrast, the use of a picosecond laser enables the precise generation of TSVs with a smaller heat affected zone. In this study, a comparison of the thermal and crystallographic defect around laser-drilled holes when using a picosecond laser beam with varing a fluence and repetition rate was conducted. Notably, the higher fluence and repetition rate picosecond laser process increased the experimentally recast layer, surface debris, and dislocation around the hole better than the high fluence and repetition rate. These findings suggest that even the picosecond laser has a heat accumulation effect under high fluence and short pulse interval conditions. To eliminate these defects under the high speed process, the CDE (chemical downstream etching) process was employed and it can prove the possibility to applicate to the TSV industry.

• 한국임상수의학회지
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• 제15권2호
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• pp.339-345
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• 1998

This study was performed to investigate the effect of acupuncture in dogs with experimentally induced thoracic disease. Twenty four dogs and 16 cats for the heart study, were divided into four groups(each of 6 in dogs, each of 4 in cats): laserpuncture, electroacupuncture, acupuncture and control group. Heart disease was induced by partial pericardiectomy, and then treatment was done once daily for 4 days. The acupoints used were Xin-shu and Nei-guan. The effect of acupuncture was evaluated by clinical symptom, blood chemical values, electrocardiogram(ECG) and histopathological findings. In dogs, acupuncture group revealed relatively fast recovery and laserpuncture group revealed secondly fast recovery after treatment. In catsl lasewuncture group revealed relatively fast recover and acnpuncture group reveaBed secondly fast recovery after treatment Sixteen dogs for the lung study, were divided into flour groups(each of 4) : laserpuncture, electroacupunchuf, acupuncture and control group. Lung disease was induced by partial lung lobectomy, and then treatment was done once daily for 4 days. The acupoints used were Fei-shu and Shen- zhu. The effect of acupuncture was evaluated by clinical symptoms blood chemical values and histopathological findings. Acupuncture and laserpuncture group revealed relatively fast recovery compared with other groups.

• 대한전자공학회논문지
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• 제23권6호
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• pp.780-788
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• 1986

1.3\ulcorner GaInAsP BH(Buried Heterostructure) lasers were fabricated on the p-InP substrate. Two step chemical etching processes and melt-back etching technique during 2nd epitaxy were used for BH active layer. BH laser had the threshold current, Ith, of 72mA(23\ulcorner), peak wavelength of 1.2937\ulcorner, nd of 10-20%, and To of 85K. They operated in single mode under pulse condition up to 1.4 Ith. CW(DC) operation was successfully performed at room temperature.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1383-1385
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• 2005

We synthesized new poly(p -phenylene vinylene) (PPV) derivatives including different portions of crosslink that could interconnect the backbone of PPV for application in optoelectronic devices such as lightemitting-diodes, photovoltaic cells, and lasers. The fluorescence and electroluminescence properties of PPV including crosslink were discussed with respect of their structure and length of crosslink unit.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.165-167
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• 1998

Nd:YAG crystals were grown by Horizontal Bridgman method. The effects of sliding rate (growth rate) of Molydbenum container, growth atmosphere and concentration of Neodymium ions on crystal qualities were investigated. The size of the crystals grown was up to 150-200 mm in length, 70 mm in width and 25-35 mm in thickness. Crystals grown under the optimum conditions were violet, transparent and could not be observed any macroscopic defects. Under the polarizing microscopoc observations with crossed polar, striations, {211} facets and inclusions were detected. With the grown crystals, prototypes of laser rods for 1.06$\mu$m laser application were manufactured and then characterized. As a result, we can get high quality of Nd:YAG laser rods with <111> and <110> axis, 63 mm in length and6.3 mm in diameter.

• 한국임상수의학회지
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• 제15권2호
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• pp.331-338
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• 1998

This study evaluated the effect of acupuncture in dogs with experimentally induced spleens pancreas and urinary bladder disease. For the spleen studys sixteen dogs were divided into four groups(each of 4 in dogs): laserfonctnreg electroacupunctnre, acupuncture and control group. Spleen disease was brought by experimentally induced spleen traumata and then treatment was done once daisy for 4 days. The acupoints used were Pi-shu and Ge-shu. The effect of acupuncture was evaluated by clinical grmptomi hematological findings and blood chemical values. Acupuncture and Iaserpunctore group revealed rotatively fast recovery compared with other sloops. For the pancreas study, sixteen dogs were divided into four groups(each of 4 in dogs): laserpuncture, electroacupuncture, acupuncture and control group. Pancreas disease was brought by experimentally induced pancreas trauma, and then treatment was done once daily for 4 days The acupoints used were Wei-shu and Pi-shu. The effect of acupuncture was evaluate6 by clinical symptom, hematological findings and blood chemical values. Laserpuncture revealed relatively frost recovery and acupuncture group revealed secondly fast recovery after treatment. For the urinary bladder study, sixteen dogs were divided into four groups(each of 4 in dogs): laserpuncture, electroacupuncture,acupuncture and control group. Spleen disease was brought by experimentally induced urinary stoner and then treatment was done once daily for 4 days. The acupuncture used were Pang Guang-shu and Shen-shu. The effect of acupuncture was evaluated by clinical symptom, hematological findings, and blood chemical values. Laserpuncture and acupuncoure group revealed relatively fast recovery compared with other groups.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.135-138
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• 2002

High-speed ejection of burnt gases from the resonator cavity is essential for performance optimization of the chemical laser system. Additionally, to maintain the population of lasing species at a level for maximum optical power, the pressure within the cavity must be of order of 10 torr. In the present study, a small-scale ejector was designed and built for parametric study of its performance. High-pressure air was used as a motive gas. Measurements include schlieren visualization and pressure distribution trace near the ejector nozzle and along the diffuser downstream of the ejector. preliminary tests showed performance of the ejector is a function of parameters including mass flow rate and stagnation pressure of the motive gas, ejector nozzle area ratio, throat area of the diffuser downstream of the ejector.

• 한국진공학회지
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• 제12권S1호
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• pp.52-55
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• 2003

GaAs/AlGaAs quantum-wire (QWR) gain-coupled distributed-feedback (GC-DFB) lasers are fabricated and characterized Constant metalorganic chemical vapor deposition (MOCVD) growth is used to avoid grating overgrowth during the fabrication of DFB structures. Numerical calculation shows large gain anisotropy by optical feedback along the DFB directions near Bragg wavelength. DFB lasing via QWR active gratings is also experimentally achieved.

• Transactions on Electrical and Electronic Materials
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• 제2권1호
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• pp.1-6
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• 2001

$C_{x}F_{y}$ polymer film was deposited in rf and dc Fluorinert vapor ($C_{7}F_{16}$) plasmas. In the plasma phase, the spatial distribution of optical emission spectra and the temporal concentration of decomposed species were monitored, and kinetics of the $C_{7}F_{16}$ decomposition process was discussed. Deposition of $C_{x}F_{y}$ film has been tried on substrates of stainless steel, glass, molybdenum and silicon wafers at room temperature in the vapor pressures of 40 and 100 Pa. The films deposited in the rf plasma showed excellent electrical properties as an insulator for multi-layered interconnection of deep-submicron LSI, i.e. the low dielectric constant ∼2.0, the dielectric strength ∼2 MV/cm and the high deposition rate ∼100nm/min at 100W input power.