• 전기의세계
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• v.10
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• pp.62-71
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• 1963

공업계측분야에 대한 계수기술은 최근획기적인 발전을 거두고있다. 계수화된 계측기는 측정정도에 있어서 개인차나 오산이 없으므로 과거의 눈금식의 계측방식은 이로 대치되어 갈것인데 그 계측 가능한 속도에 있어서 종래의 진공관보다 Transistor식이 되면 훨씬 고속도까지도 계수가 쉽게 되고 장치 및 계수표시용소비전력도 개량되어가고 있다. 이러한것이 되므로서 높은 주파수측정, 짧은 시간측정은 물론이고 전기적인 진폭의 크기를 Analog to Digital 변환기로서 정밀도가 높은 계측을 가능하게 하고 특히 방사능 측정에 있어서 종래의것보다 더 고속화되므로서 방사능의 완전한 성질을 파악할 수 있을 것이다. 그것은 1Cure의 방사능이 3.7*$10^{10}$dps의 붕괴수를 갖고 있으나 현재는 약 2.8*$10^{7}$ cps정도의 계측이 가능할 따름이다. 따라서 계측속도를 더 향상시키므로서 강한 방사능계측도 가능하게 된다. 이러한 고속계수문제의 해결을 하기 위하여 Transistor회로로서 두가지면으로 추구되고 있다. 그 하나는 고속도용 Transistor자체의 개발이며 또하나는 회로적인 개량연구이다. 여기서는 후자에 관해서만 생각하고, 거기에 적합한 Transistor를 얻었을때의 설계기준과 기본적인 실험결과에 관해서 논하기로 한다.

• Journal of the Korean Solar Energy Society
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• v.28 no.3
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• pp.67-73
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• 2008

This study has been carried out to investigate the effect of vacuum on the thermal performance of a nonglass evacuated tube. A series of measurements are made indoors to monitor the temperature change of the absorber plate contained in the evacuated tube under different conditions of vacuum and heat fluxes. Those temperatures measured at the thermal equilibrium could be used to assess the heat losses to the ambient in link with the steady operation of non-glass evacuated tubes for solar exploitation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.371-372
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• 2008

In this paper, we experimentally investigated discharge phenomena inside vacuum interrupter at 1 to 20 Torr to simulate the vacuum leakage. We used glass type of vacuum interrupter where the internal pressure and the type of gasses can be varied according to requirement. The experiment is conducted under ac applied voltage and the experimental circuit is constructed to simulate the actual circuit used in cubical type insulated switchgear. We used two types of gases such as air and $SF_6$. The use of glass type vacuum interrupter allowed us to measure discharges occurring in vacuum interrupter optically. We measured and discussed the discharge occurring in both gases with a current transformer and ICCD camera. We also revealed that electromagnetic wave spectra emitted by the discharge have same frequency range for both gasses.

• Journal of the Korean Professional Engineers Association
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• v.30 no.3
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• pp.43-51
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• 1997

Vacuum tubes are electron tubes in which the motion of electrons are utilized. There are many kinds of vacuum tubes, e.g. diode tubes, triode tubes, pentodes. muti-tubes and etc. Generally accommodated in glass tube, its eletrodes can be seen easily from outside and it easy to understand. In 1884 Edison discovered a current flow in the vacuum tube. He could not, however, explain this phenomenon. This is called Edison effect. In 1904 Fleming developed the backup for the practical diode theory. The most important milestone in this early history of electronics came in 1906 when De Forest put a third electrode (a grid) into the above, and thus invented the triode tube. It is 90 years since the triode was invented by De Forest (as of 1996) and 100 years (centennial also as of 1996) since the specific electric change e/mo$_0$ ≒ 1.7589 ${\times}$ 1011 (C/kg) was confirmed by the English scientist Thomson in 1896. On the occasion of the 90th and 100th anniversary of these inventions and discovery, E would like to describe the rise and 1111 of the vacuum tubes and the current status of these tubes.

• Journal of Korean Academy of Nursing
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• v.42 no.3
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• pp.443-451
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• 2012

Purpose: This study was done to compare the rates of hemolysis and repeated sampling in blood samples obtained by a syringe needle versus a vacuum tube needle. Methods: A randomized, prospective study was used to evaluate the differences between the two blood sampling methods. The study group consisted of patients seen in the emergency department (ED) for blood sampling to determine electrolyte level. ED patients were randomly assigned to either the syringe group or the vacuum tube group. All blood samples were collected by experienced ED nurses and hemolysis was determined by experienced laboratory technologists. Data were analyzed using Fisher's exact test and binary logistic regression. Results: One hundred forty-five valid samples were collected (74 in the syringe group versus 71 in the vacuum tube group). 5 of 74 (6.8%) blood samples in the syringe group and 8 of 71 (11.3%) in the vacuum tube group hemolyzed. Repeated blood sampling occurred for 2 of 74 (2.7%) and 3 of 71 (4.2%) in each group respectively. There were no significant differences in rates of hemolysis and repeated sampling between two groups (B=1.97, p=.204; B=2.36, p=.345). Conclusion: Venipuncture with syringe needles can be recommended for ED nurses to obtain blood samples.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.90-94
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• 2023

Carbon fiber(CF) with excellent thermal conductivity and electrical conductivity is attracting attention as an alternative material because metal heating elements have problems such as high heat loss and fire risk. However, since CF is oxidized and disconnected at about 200℃ or higher, the application of heating elements is limited, and CF heating elements in the form of vacuum tubes are currently used in some commercial heaters. In this work, polyimide(PI) with high heat resistance was coated on the surface of carbon fiber by electrophoretic deposition to prevent oxidation of CF in the atmosphere without using a vacuum tube, and the coating thickness and heat resistance were investigated according to the applied voltage. The heater made by connecting the PI-coated CF heating elements in series showed stable heating characteristics up to 292℃, which was similar to the heating temperature result of the heat transfer simulation. The PI layer coated by the electrophoretic deposition method is effective in preventing oxidation of CF at 200℃ or higher and is expected to be applicable to various heating components such as secondary batteries, aerospace, and electric vehicles that require heat stability.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.2
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• pp.22-29
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• 2018

The purpose of this study was to evaluate the performance of a solar collector to introduce natural convection in a water tank as a means of obtaining warm water. Numerical analysis was performed to predict the characteristics of the solar collector and its performance was verified using an experimental method. The single vacuum structure of the collector enabled natural convection when it was fitted on the water tank. Based on numerical analysis, warm water of $31-54^{\circ}C$ was obtained when the inlet temperature of cold water was $20^{\circ}C$. Furthermore, the temperature of the warm water could be predicted under various conditions as well as the experimental conditions created for this study.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.19-19
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• 2003

에디슨 전구가 발명된 지 1 세기가 지난 지금, 반도체 기술에 의해 또 다른 빛의 혁명이 시작되고있다. 고출력 백색 LED를 이용한 반도체 조명이 그 주역이다. 종래의 단순 표시기에서 사용되었던 저휘도 LED가 이제는 빛의 3원색인 적색, 녹색 및 청색뿐만 아니라, 모든 가시광선의 영역과 나아가서는 자외선 영 역까지 고출력 LED 구현이 가능하게 되었고, 또한 빛의 3원색을 결합시킨 백색 LED의 광효율이 획기적으로 증가함에 따라 차세대 조명기기에의 응용이 눈앞에 다가오고 있는 실정이다. 이와 같은 기술의 변화의 파라다임은 과거 진공관 시대가 트랜지스터 시대로 변모되었고, 현재 CRT 모니터 시대에서 LCD 모니터 시대로 급변하는 것과 같이, 미래에는 백열전구 시대에서 LED 반도체 조명 시대로 바뀌게 될 것을 기대 할 수가 있을 것이다. LED 반도체 조명은 무엇보다도 기존의 조명기기보다 전력 소모가 매우 적고 10년 이상의 수명을 갖고 있어서 유지보수 측면에서의 효용성, 내구성과 견고성과 더불어 다양한 직접화 및 디자인 등의 많은 장점을 갖고 있어서 빛이 필요한 모든 다양한 분야에서 사용이 가능하기 때문에 그 중요성이 새삼 강조되고 있다. 따라서 현 정부에서는 차세대 성장 동력 산업 38개 사업 중 LED 사업을 그 중 하나의 산업으로 지정만 바가 있다. 본 논문에서는 LED의 개발 역사와 선진국들의 고휘도 및 고출력 LED 신기술 동향을 고찰하며, 시장의 다양한 응용의 예와 LED 반도체 조명을 구현하기 위해 극복해야 할 기술들을 전체적으로 분석하여 제시하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.12
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• pp.785-790
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• 1999

This research has been carried out to develop a low-energy large-aperture pulsed electron beam generator (LELA), 200keV 1A, for industrial applications. One of the most important feature of this electron beam generator is large electron beam cross section of $190cm^2$. Low energy electron beam generators have been used for water cleaning, flue gas cleaning, and pasteurization, etc. In these applications the cross sectionof the e-beam is related to reaction efficiency. Another important feature of this LELA EB generator is easy maintenance because of its simple structure and relatively low vacuum operation compared to the conventional EB generators. The conventional EB generators need to be scanned because the small cross section thermal electron emitters are used in the conventional EB generators which have small EB cross section. In this research, we use the secondary electrons generated by ion bombardment on the HV cathode surface as a electron source. Therefore we can make any shape of EB cross section without scanning.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.243-244
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• 2008

We experimentally investigated discharge phenomena inside vacuum interrupter at 1 to 20 Torr to simulate the vacuum leakage. We used glass type of vacuum interrupter where the internal pressure and the type of gasses can be varied according to requirement. The experiment is conducted under ac applied voltage and the experimental circuit is constructed to simulate the actual circuit used in cubical type insulated switchgear. We used two types of gases such as air and $SF_6$. The use of glass type vacuum interrupter allowed us to measure discharges occurring in vacuum interrupter optically. We measured and discussed the discharge occurring in both gases with a current transformer and ICCD camera. We a1so revealed that electromagnetic wave spectra emitted by the discharge have same frequency range for both gasses.