• Journal of Advanced Marine Engineering and Technology
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• 제30권6호
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• pp.740-745
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• 2006

This study suggested the occurrence source of weld-defects and its solution methods in a welding of Electrolyte injection hole by pulsed Nd:YAG laser. In experiment, the ramp down was used in order that solidification crack was removed. Furthermore. shrinkage stress and heat input were reduced by changing of weld trajectory and defocused distance. As a results of a experiment, a sound weld bead shape and crack-free weld bead can be obtained. In conclusion this show that the welding stability is greatly affected by modulation of laser pulse shape for the same laser energy and welding parameters.

• 대한전자공학회논문지
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• 제25권7호
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• pp.780-790
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• 1988

We have studied the hot-carrier-induced degradation caused by the high channel electric field due to the decrease of the gate length of MOSFET used in VLSI. Under DC stress, the condition in which maximum substrate current occures gave the worst degradation. Under AC dynamic stress, other conditions, the pulse shape and the falling rate, gave enormous effects on the degradation phenomena, especially at 77K. Threshold voltage, transconductance, channel conductance and gate current were measured and compared under various stress conditions. The threshold voltage was almost completely recovered by hot-injection stress as a reverse-stress. But, the transconductance was rapidly degraded under hot-hole injection and recovered by sequential hot-electron stress. The Si-SiO2 interface state density was analyzed by a charge pumping technique and the charge pumping current showed the same trend as the threshold voltage shift in degradation process.

• 한국자동차공학회논문집
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• 제6권3호
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• pp.115-122
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• 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.

• 대한의용생체공학회:의공학회지
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• 제22권3호
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• pp.275-283
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• 2001

This study was performed to extract and analyze the biosignals to find the relationship between the level of anesthesia and the variations of physiological parameters during epidural anesthesia. Seven male and twenty female patients(ages from 45 to 70 years old) were participated for the experiment, and ECGs, PPGs, SKTs, SCRs were obtained during anesthesia. As results, the HF/LF ratios of HRV were decreased after the injection anesthetics. For skin temperatures, values measured from the palm was reduced and the temperatures from four channels, measured from armpit through the right side of the body, were increased. SCRs were decreased for all channels after the injection of anesthetics. However the heart rate and PPGs showed no significant changes. It was concluded that the injection of anesthetics result the changes in biosignals, and it could be explained by the degree of the sympathetic and/or parasympathetic nerve activities. Results of this study could provide the valuable information for the estimation of level for the spinal and general anesthesia, and could be extended to the development of a system which could quantify the level of anesthesia.

• Child Health Nursing Research
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• 제13권1호
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• pp.66-72
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• 2007

Purpose: This study was done to evaluate the effects of distraction using balloon art on pain experienced by preschool children when undergoing an intravenous injection. Methods: Participants were 40 hospitalized preschool children. Children in the experimental group (20) were distracted by balloon art while undergoing an intravenous injection. Children in the control group (20) received regular care. Pain experienced by the children was measured using self-report, observation tools, heart rate and oxygen saturation. The data were analyzed using the SAS program. Results: Compared with the control group, children in the experimental group showed significant difference in pain as shown by pulse rate. However, children in the experimental group did not show a decrease in pain in the self-report or behavior observation when compared with children in the control group. Conclusion: Distraction using balloon art can be used to reduce pain for preschool children when undergoing an intravenous injection. Further nursing interventions need to be developed and provided to preschool children when undergoing painful procedures.

• 대한핵의학회지
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• 제20권2호
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• pp.79-84
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• 1986

The opiate antagonist, naloxone, was injected for the reversal of hypotension due to Korean hemorrhagic fever, and the authors observed changes in pituitary hormones. In the hypotensive phase of the Korean hemorrhagic fever, the f-endorphin was high, and normalized granually in the diuretic and convalescent period. The naloxone raised the pulse rate and the blood pressure within 30 minutes without change in the central venous pressure. Around 30 minuted after the injection of the naloxone, the $\beta-endorphin$, ACTH and cortisol rose. The prolactin fell down 60 minutes after the naloxone injection.

• 한국분무공학회지
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• 제19권1호
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• pp.9-14
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• 2014

Performance of DI diesel engine with high-pressure fuel injection equipment is directly related to its emission characteristics and fuel consumption. So, the electro-hydraulic injector for the common-rail injection system should be designed to meet the precise high fuel delivery control capability. Currently, most high pressure injector in use has a needle driven by the solenoid coil energy or the piezo actuator controlled by charge-discharge of output pulse current. In this study, macroscopic spray approaching method was applied under constant volume chamber to research the performance of three different injectors : solenoid, indirect-acting piezo and direct-acting piezo type for CR direct-injection. LED back illumination for Mie scattering was applied on the liquid spray visible of direct-acting piezo injector, including hydraulic-servo type solenoid and piezo-driven injectors. As main results, we found that a direct-acting piezo injector had better a spray tip penetration than hydraulic-servo injectors in spray visualization.

• 한국분무공학회지
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• 제10권3호
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• pp.29-37
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• 2005

The spray and acoustic characteristics of a gas/liquid swirl coaxial injector are studied experimentally. The self-pulsation is defined as a pressure and flow rate oscillations by a time-delayed feedback between liquid and gas phase. Self-pulsation has strong influences on atomization and mixing processes and accompanies painful screams. So. the spray and acoustic characteristics are investigated. Spray patterns are observed by shadow photography technique in order to determine the onset of self-pulsation. And self-pulsation boundary with Injection conditions and recess length is get. To measure the frequency of the spray oscillation. oscillation of the laser intensity which passes through spray is analyzed by Fast Fourier Transform. For acoustic tests, a PULSE System was used. Acoustic characteristics of a swirl coaxial injector are investigated according to the injection conditions. such as the pressure drop or the liquid and gas phase. and injector geometries. such as recess length and gap size between the inner and outer injector. Front the experimental results. the increase of recess length leads to the rapid increase of the sound pressure level. And as the pressure drop of the liquid phase increases. the frequency of the self?pulsation shifts to the higher frequency. The frequency of spray oscillations is the same as that of the acoustic fields by self-pulsation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 추계학술대회 논문집
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• pp.227-228
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• 2012

본 논문에서는 스위칭 주파수의 구형파 펄스 전압 주입을 이용한 센서리스 제어시 회전자 초기 위치 추정 방법을 제안하였다. 추정된 동기좌표계 d축에 스위칭 주파수의 구형파 펄스 전압을 주입하여 회전자의 위치를 추정하고, 인덕턴스 포화현상을 이용하여 회전자의 극성을 판별하였다. 제안된 방법은 실험을 통하여 그 타당성을 검증하였다.

• 전기전자학회논문지
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• 제28권1호
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• pp.97-103
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• 2024

일부 약물은 피부의 표피층 이하로 주입될 때 훨씬 더 효과적인 의료 효과를 제공할 수 있다. 그러나 전통적인 비침습 주입 장치는 피부의 한 부분에 상대적으로 많은 양의 약물을 전달하며, 이는 조직층 구조를 분리하여 멍과 출혈을 유발할 수 있다. 피부의 큰 표면적에 빠른 반복율로 소량을 주입함으로써 환자의 부상과 통증을 감소시킬 수 있다. 이를 위해서 약액을 분사하는 압력은 빠른 속도로 침투 가능 압력까지 상승되고 빠르게 하강하여 주입되지 않는 되튀김량을 줄이고, 주입량을 최소화해야한다. 이러한 형태의 비침습 주사 장치가 개발되었지만 그 장치들의 의학적 효능은 분석된 바가 거의 없다. 따라서 이 연구에서는 속도가 ~310m/s인 마이크로젯을 분사하는 레이저 유도 마이크로젯 장치를 개발했다. 펄스 시간은 400~800 ㎲이며 각 분사가 초당 10번 반복되는 속도로 약물을 약 1 µL 분사할 수 있습니다. 이러한 원리를 사용하여 우리는 마우스 모델에 대한 약물 주사의 효과를 평가했다. 마우스 모델에 인슐린 용액을 주입한 후 혈중 인슐린 농도를 측정하였으며, 일반 바늘 주사 주법과 동일한 값을 얻었다.