• 소성∙가공
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• 제16권3호
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• pp.157-162
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• 2007

The hydropiercing process gives a lot of advantages to the tube hydroforming such as cost reduction and high productivity. However it has a drawback, the amount of deflection around the hole is bigger than that of conventional die piercing process. The deflection can cause the problem at the assembly process of stamped parts and hydroformed part. Therefore the reduction of deflection is one of the most important issues for hydropiercing process. In this study, the deflection around hydropierced hole was investigated by experiment. As a result of investigation, the amount of deflection is influenced by the internal pressure, the material thickness' and the size of hole. Especially the hole size is most influencing factor on the deflection around the hydropierced hole.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.779-780
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• 2014

This paper dealt with numerical estimation of pressure pulsation of the refrigerant in a suction pipe of the compressor. To evaluate the effect of reduction of pressure pulsation, a pipe system with tube was simulated using F.S.I.(Fluid-structure interaction) analysis. A commercial program was used for calculating behavior of pressure. The numerical simulation for pressure ratio of before and after going though internal structure were carried out. As a result, it was verified that the pressure after passing structure is less than the pressure before passing internal structure depending on the longitudinal frequency of structure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.489-490
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• 2008

This paper describes the analysis of electric field distribution of high voltage polymeric bushing with structure. The high voltage bushing consists of FRP tube and housing made of LSR. The field control can be achieved by means of the design of such internal field shaper and top corona ring as grading electrodes. In accordance, the optimized design uses both internal and external elements for electric stress grading at critical parts of the bushing. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymeric bushing.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권6호
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• pp.230-235
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• 2003

In this paper, a superposed discharge type ozonizer with an internal dielectric that can be made into a vacuum tube has been designed and fabricated. Ozone generation and discharge characteristics have been investigated in accordance with output voltage of power supply, flow-rate, discharge power and vacuum of inside internal dielectric. Pure oxygen was used as the supply gas of the ozonizer. Ozone concentration and ozone generation are gradually increased when discharge power is increased at the same flow-rate and they are both proportional to the vacuum level. As such, the maximum ozone concentration of 8840 ppm was obtained at vacuum 0.1 Torr and flow-rate 0.5 $\ell$/min.

• Journal of Information Display
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• 제12권2호
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• pp.69-75
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• 2011

A new electron source and an electron collection source were found for the closure of the internal electron circuit inside fluorescent lamp (FL) tubes. The sources are formed in front of the polarized electric-insulator particles on the metal electrodes at both ends of the FL tube. The appearance and disappearance of both sources are controlled by the electric voltages applied to the metal electrodes. The electrons and $Ar^+$ for the sources are generated by the ionization of the Ar atoms, and they return to the Ar atoms at the electron collection source. Thus, the Ar atoms are preserved in the FL tubes, ensuring a long operation life for such tubes.

• 한국분무공학회지
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• 제26권4호
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• pp.197-203
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• 2021

In gasoline direct injection injectors, cavitation can be generated inside the hole because of their high injection pressure. In this paper, the effects of cavitation development in injector were investigated depending on the various hole drilling angles were investigated by a numerical method. In order to verify the internal flow model, injection rate and injection quantity of individual holes were measured. The BOSCH long tube method was used to measure the injection rate. As a result, even if the hole diameters were the same, the discharge coefficient differed by up to 10% depending on the hole angle. Moreover, if the hole drilling angle became greater than 30°, the area coefficient and the discharge coefficient decreased as the nozzle outlet was blocked due to cavitation.

• Clinical Endoscopy
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• 제57권3호
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• pp.293-301
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• 2024

Cap-assisted endoscopy refers to a procedure in which a short tube made of a polymer (mostly transparent) is attached to the distal tip of the endoscope to enhance its diagnostic and therapeutic capabilities. It is reported to be particularly useful in: (1) minimizing blind spots during screening colonoscopy, (2) providing a constant distance from a lesion for clear visualization during magnifying endoscopy, (3) accurately assessing the size of various gastrointestinal lesions, (4) preventing mucosal injury during foreign body removal, (5) securing adequate workspace in the submucosal space during endoscopic submucosal dissection or third space endoscopy, (6) providing an optimal approach angle to a target, and (7) suctioning mucosal and submucosal tissue with negative pressure for resection or approximation. Here, we review various applications of attachable caps in diagnostic and therapeutic endoscopy and their future implications.

• Tuberculosis and Respiratory Diseases
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• 제57권5호
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• pp.465-469
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• 2004

저자들은 패혈증이나 혈액응고장애가 이상이 없는 소방이 형성된 흉막삼출 환자에서 비교적 안전한 것으로 알려진 urokinase의 주입 후에 발생한 혈흉과 이로 인한 hypovolemic shock을 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

• Tuberculosis and Respiratory Diseases
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• 제79권3호
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• pp.179-183
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• 2016

A 59-year-old man presented with acute dyspnea following sudden productive cough and expectoration of a full cup of "blood-tinged" sputum. He had been diagnosed with hepatitis B virus-related hepatocellular carcinoma and had received transarterial chemoembolization 5 years ago for a 20-cm hepatic mass; he denied any history of hematemesis and the last esophagogastroduodenoscopy from a year ago showed absence of varix. Chest computed tomography (CT) with angiography showed new appearance of right basal lung consolidation but no bleeding focus. Despite the use of systemic antibiotics, the patient developed respiratory failure on day 7 of hospitalization. After intubation, a massive amount of brown sputum with anchovy-paste-like consistency was suctioned via the endotracheal tube. Bronchoscopic toileting was performed and the patient was extubated. In the ward, he continued to expectorate the brown sputum. On day 25 of hospitalization, a repeat CT scan showed simultaneous disappearance of the pneumonic consolidation and the necrotic fluid within the hepatic mass, suggesting the presence of a fistula. He has continued to receive systemic antibiotics, sorafenib, and entecavir, and follow up by respiratory and hepato-oncology specialists.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.78-81
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• 1995

In imaging the samples or human internal organs in a tube shape, general RF-probe types (that encircles a sample or places on top of the sample) are usually unsuitable for the internal imaging due to the degradation of signal-to-noise ratios(SNR's). In the present study the inside-out probes for Magnetic Resonance Imaging (MRI) have been constructed in the three different shapes such as an anti-solenoidal, a saddle and a dual surface types which are positioned as close to the area as possible by putting the probe inside the tubelike sample to improve filling factor. RF-field distributions have also been calculated depending upon the geometrical changes of anti-solenoid probes. Moreover, the performance of the inside-out probes has been checked by measuring SNR's of the images acquired. The inside-out probes constructed in this study produced better SNR's and rf-field uniformity in the area close to the probes in comparing with any other commercial probes. There is a high possibility that the constructed probes in the present study are applicable to the diagnosis of human bodies.