• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.120-125
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• 2006

In contrast to the conventional trigatron switch in which the currents are constricted by the z-pinch mechanical the new switch operates in an inverse pinch geometry formed by a pair of spiral electrodes in a sealed-off type. Inverse pinch switch greatly reduces hot spot formations and protects the electrode surfaces. The switch can be initiated with an electrical trigger electrode. Advantages of the new switch over the conventional switches are longer useful life, high current capability and lower inductance due to the dispersed and moving current sheet. These improved characteristics may make the inverse pinch switch suitable for pulse power systems.

• Journal of Chest Surgery
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• v.41 no.4
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• pp.504-507
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• 2008

Implantable central venous catheters (Chemoport) are increasingly being used for vascular access, parenteral nutrition and administering chemotherapeutic agents. As with most invasive procedures, central venous catheterization is associated with numerous potential complications such as infection, thoromboembolism and occlusion. A rare but serous complication is the catheter fracture. We present here three cases of catheter fracture as a consequence of Pinch off syndrome, and we include a review of the relevant literature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.371-377
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• 2008

In order to obtain fundamental knowledge of atomization, the three dimensional unsteady phenomenon of pinch off was numerically studied by developed method. Not only liquid shapes but also velocity distributions of numerical results were compared with corresponding experimental ones. They showed satisfactorily good agreement at least in a qualitative sense. The liquid jet shapes, the pressure and velocity distributions, and the inner flow structures were clarified through the comparisons of distinctly different flow fields due to presence or absence of surface tension. The condition of pinch off, which had close correlation with fluid acceleration at injection, was clearly specified.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.498-501
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• 2002

In this paper, we designed double gate(DG) MOSFET structure which has main gate(MG) and two side gates(SG). We have simulated using TCAD simulator. DG MOSFET have the main gate length of nm and the side gate length of 70nm. Then, we have investigated the pinch-off characteristics, drain voltage is changed from 0V to 1.5V at VMG=1.5V and VSG=3.0V. In spite of the LMG is very small, we have obtained a very good pinch-off characteristics. Therefore, we know that the DG structure is very useful at nino scale.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1629-1631
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• 2003

고전압 대전류 펄스파워에 사용되는 스위치는 여러 종류가 사용되고 있는데, 커페시터에 저장된 초기의 전자 에너지를 시공적으로 압축하여 수ns ${\sim}$ 수ms의 짧은 시간안에 고출력을 발생시키기 위해서는 펄스파워 장치에 사용되는 커패시터, 인덕터, 저항, 스위치등 회로 소자들의 임피이던스가 작아야 할 필요성이 대두 된다. 따라서 Inverse Pinch Switch(IPS)는 이런 조건을 만족시킬수 있는 스위치로서 각광을 받고 있다. 본 논문에서는 전기트리거형 IPS의 금속 전극부와 절연 ceramic를 brazing하여 sealed off type의 스위치의 제작 과정과 특성을 연구 하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.7
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• pp.1074-1078
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• 2002

In this paper, we designed double gate(DG) MOSFET structure which has main gate(MG) and two side gates(SG). We have simulated using TCAD simulator U .WOSFET have the main gate length of %m and the side gate length of 70nm. Then, u'e have investigated the pinch-off characteristics, drain voltage is changed from 0V to 1.5V at VMG=1.5V and VSG=3.0V. In spite of the LMG is very small, we have obtained a very good pinch-off characteristics. Therefore, we know that the DG structure is very useful at nano scale.

• Journal of Chest Surgery
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• v.51 no.5
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• pp.333-337
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• 2018

Background: Pinch-off syndrome (POS) is a rare complication after totally implantable venous access device (TIVAD) implantation. In cancer patients, it is important to prevent this rare complication and to recognize it early if it does occur. We present a case series of POS after TIVAD implantation and the results of a literature search about this complication. Methods: From July 2006 to December 2015, 924 permanent implantable central venous catheter implantation procedures were performed. The most common indication was vascular access for chemotherapy. Results: POS occurred in 5 patients in our clinic. Two patients experienced POS within 2 weeks, and the other 3 patients were admitted to department of surgery, Istanbul Faculty of Medicine at 6 to 14 months following implantation. The catheters were found to be occluded during medication administration, and all patients complained of serious pain. The transected fragments of the catheters had migrated to the heart. They were successfully removed under angiography with a single-loop snare. Conclusion: POS is a serious complication after TIVAD implantation. It is important to be aware of this possibility and to make an early diagnosis in order to prevent complications such as drug extravasation and occlusion events.

• Journal of computational fluids engineering
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• v.17 no.3
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• pp.33-38
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• 2012

The droplet ejection behavior from drop-on-demand printhead are investigated numerically for Newtonian and shear-thinning fluid. The numerical simulation is performed using a volume-of-fluid model. In this study, we compare the printable range in terms of Z number and pinch-off time for Newtonian and shear-thinning fluids. The printability range are found to be 1.08 $$\leq_-$$ Z $$\leq_-$$ 12.9 for Newtonian fluid and 0.8 $$\leq_-$$ Z $$\leq_-$$ 12.9 for shear-thinning fluid. However, air entrainment is observed during merging of primary and satellite droplet within the printability range. The pinch-off time of the shear-thinning fluid is apparently shorter compared to the corresponding Newtonian fluid due to shear-thinning effects and the differences in the pinch-off time is enlarged significantly when the capillary number is larger than 0.5.

• Journal of the Korean Society of Visualization
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• v.20 no.3
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• pp.10-18
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• 2022

We present an experimental investigation on emulsions created during the impact process between a surfactant-laden droplet and an oil layer on water. By varying the surfactant concentration and the viscosity of oil layer, we created emulsions and visualized them using multi-dimensional high-speed imaging. Our analysis shows that the emulsions are more likely to be unstable and decay within a minute if the impacting droplet contains more surfactant. We also found that there are three mechanisms of generation of emulsions depending on the concentration of surfactant and the viscosity of oil layer; the jet pinch-off, cavity pinch-off, and tearing of oil layer. Jet and cavity pinch-off turned out to be dominant mechanisms for high oil viscosities, while tearing of oil layer is dominant for low oil viscosities. Our result is potentially useful in designing optimal dispersant properties for offshore oil contamination.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1588-1593
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• 2008

This paper describes a real-time isometric pinch force prediction algorithm from surface electromyogram (sEMG) using multilayer perceptron (MLP) for human robot interactive applications. The activities of seven muscles which are observable from surface electrodes and also related to the movements of the thumb and index finger joints were recorded during pinch force experiments. For the successful implementation of the real-time prediction algorithm, an off-line analysis was performed using the recorded activities. Four muscles were selected for the force prediction by using the Fisher linear discriminant analysis among seven muscles, and the four muscle activities provided effective information for mapping sEMG to the pinch force. The MLP structure was designed to make training efficient and to avoid both under- and over-fitting problems. The pinch force prediction algorithm was tested on five volunteers and the results were evaluated using two criteria: normalized root mean squared error (NRMSE) and correlation (CORR). The training time for the subjects was only 2 min 29 sec, but the prediction results were successful with NRMSE = 0.112 ${\pm}$ 0.082 and CORR = 0.932 ${\pm}$ 0.058. These results imply that the proposed algorithm is useful to measure the produced pinch force without force sensors in real-time. The possible applications include controlling bionic finger robot systems to overcome finger paralysis or amputation.