• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.351-358
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• 2018

In this study, we propose a method of suppressing the leakage noise signal of motor assembly through the test. The motor assembly is mounted on outside of the aircraft to rotate an antenna and must satisfy RE102 requirement on MIL-STD-461F in terms of electromagnetic interference. It is confirmed by RE102 test result hat the leakage noise signal of the equipment occurs due to external influx through the power and control cable and rotation of the motor. And it is ascertained that the part where internal/external physical shielding is difficult to rotate is the leakage path. To reduce the leakage noise signal, the electrical ground reinforcement and the electric shielding structure considering the operation of the equipment is applied and it is verified that the requirement is satisfied. Finally, we verified that required specification are met by applying circular corrugated choke with interlocking shapes and conductive grease to the noise leakage path.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1097-1104
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• 2016

The infrared camera is difficult to satisfy the RE-102 specification of Mil-Std-461. Especially, in the case of UAV electronics, shielded cable is not used, so it is difficult to meet the electromagnetic compatibility standard. In the RE-102 test of the IR camera for UAV, radiated noise exceeding 30 dBuV/m was observed in the range of 50 MHz to 200 MHz. As a result of pcb em scan, peak noise which caused by the harmonic frequency of the digital control signal clock was observed. Radiated noise was reduced by up to 22.9 dBuV/m by applying the spread spectrum clock generator(SSCG) with 3 % down spreading method to the camera control clock.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2006.04a
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• pp.101-102
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• 2006

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.329-337
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• 2007

This paper deals with electromagnetic tests of the GPS receiver system that should be developed to satisfy emission and susceptibility requirements for a satellite launch vehicle. Performance of the GPS receiver system against electromagnetic environment that is improved through several tests satisfies all requirements about electromagnetic tests. The outline of the electromagnetic tests and emission test results of CE102, CE106 and RE102 on MIL-STD-461E are described in Part I.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.870-875
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• 2023

In this paper, we analyzed the revised guidance on electromagnetic (EM) interference qualification of Regulatory Guide 1.180 (Revision 2), which is published by the U.S. Nuclear Regulatory Commission for electromagnetic compatibility qualification for nuclear safety, by comparing it with that of the previous version. We confirmed that the test methods and the acceptance criteria of both CE101 and CE102 tests for conductive emission and RE102 test for radiating emission are changed in the recently revised Regulatory Guide 1.180 (Revision 2). Furthermore, we found that the revised Regulatory Guide 1.180 provides flexibility in the use of alternative methods for EM interference (EMI) qualification, in that a mix of the various base-standards is technically allowed. In addition, the primary revision of the updated Regulatory. Guide 1.180 is that MIL-STD-461G is to be adopted as the latest base-standard, instead of MIL-STD-461E. To evaluate the influence on EMI qualification for nuclear safety due to the endorsement of MIL-STD-461G, we thoroughly analyzed the modifications in the acceptance criteria and test methods for EMI qualification, and then validated the analyzed effect on the EMI qualification, which is caused by the revision of MIL-STD-461, by performing electromagnetic simulation for equipment under RE102 test.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.101-102
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• 2005

• Journal of Advanced Navigation Technology
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• v.24 no.1
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• pp.1-8
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• 2020

In this research, we develop an airborne equipment radiating S/C-band signal to a target located at a long distance. RF interface of the equipment comprises band-specific transmitters and an broadband antenna to satisfy EIRP(effective isotropic radiated power) requirements. The equipment is in a shape of a POD like an aircraft fuel tank. The measured weight of the equipment is 119.8 kg, the CG(center of gravity) is 1391.35 mm and the MOI(moment of inertia) are 46.07 ± 0.05(I_yy) kg·㎡, 45.36 ± 0.09(I_zz) kg·㎡. All results are found to meet the requirements for aircraft installation. To verify flight safety, EMI(electromagnetic interference) tests (RE102, CE102), environmental tests (high/low temperature operation, altitude), intra-system EMC(electromagnetic compatibility) and HERP(hazards electromagnetic radiation personnel) tests have been conducted and all the test results met the requirements. It is confirmed that the equipment could be mounted on the aircraft by meeting all electrical and mechanical requirements.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2043-2046
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• 2002

This paper studies on Sun interference effects or Sun outage effects on C-band satellite reception signal for THAICOM2. The THAICOM2 satellite is at 78.5 degree East 〔co-located with THAICOM3〕. The down link station was located in Khon-kaen, longitude 102.83 degree East and latitude 16.43 degree North. The antenna diameter is 4.6 meters for C-band downlink station. Total 9 times of sun interference events were occurred during summer and fall of 2001 and these about 53 minutes altogether. The Maximum CM degradation of the THAICOM2 system was around 11 dB. The Sun interference events of 53 minutes of one year are 0.0122 percents of the C-band contact time when 21 hours of contact time is used f3r broadcasting a day.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.181.1-181.1
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• 2015

용액 공정을 이용한 Resistive random access memory (ReRAM)은 간단한 공정 과정, 대면적화, 저렴한 가격 등의 장점으로 인해 큰 관심을 받고 있으며, HfOx, TiOx, AlOx 등의 산화물이 ReRAM 절연 막으로 주로 연구되고 있다. 더 나아가 최근에는 organic 물질을 메모리 소자로 사용한 연구가 보고되고 있다. 이는 경제적이며, wearable 또는 flexible system에 적용이 용이하다. 그럼에도 불구하고, organic 물질을 갖는 메모리 소자는 기존의 산화물 소자에 비해 열에 취약하며 전기적인 특성과 신뢰성이 우수하지 못하다는 단점을 가지고 있다. 이를 위한 방안으로 본 연구에서는 AlOx - polymethylmethacrylate (PMMA) blended thin film ReRAM을 제안하였다. 이는 organic물질의 전기적 특성을 개선시킬 뿐 아니라, inorganic 물질을 wearable 소자에 적용했을 때 발생하는 crack과 같은 기계적 물리적 결함을 해결할 수 있는 새로운 방법이다. 먼저, P-type Si 위에 습식산화를 통하여 SiO2 300 nm 성장시킨 기판을 사용하여 electron beam evaporation으로 10 nm의 Ti, 100 nm의 Pt 층을 차례로 증착하였다. 그리고 PMMA 용액과 AlOx 용액을 초음파를 이용하여 혼합한 뒤, 이 용액을 Pt 하부 전극 상에서 spin coating방법으로 1000 rpm 10초, 5000 rpm 30초의 조건으로 증착하였다. Solvent 및 불순물 제거를 위하여 150, 180, $210^{\circ}C$의 온도로 30 분 동안 열처리를 진행하였고, shadow mask를 이용하여 상부 전극인 Ti를 sputtering 방식으로 100 nm 증착하였다. 150, 180, $210^{\circ}C$로 각각 열처리한 AlOx - PMMA blended ReRAM의 전기적 특성은 HP 4156B semiconductor parameter analyzer를 이용하여 측정하였다. 측정 결과 제작된 소자 전부에서 2 V이하의 낮은 동작전압, 안정된 DC endurance (>150cycles), 102 이상의 높은 on/off ratio를 확인하였고, 그 중 $180^{\circ}C$에서 열처리한 ReRAM은 더 높은 on/off ratio를 갖는 것을 확인하였다. 결론적으로 baking 온도를 최적화하였으며 AlOx - PMMA blended film ReRAM의 우수한 메모리 특성을 확인하였다. AlOx-PMMA blended film ReRAM은 organic과 inorganic의 장점을 갖는 wearable 및 system용 비휘발성 메모리소자에 적용이 가능한 경제적인 기술로 판단된다.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.97-102
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• 2003

An experimental study is conducted to investigate the effects of duct corrugation angle on heat/mass transfer characteristics in wavy ducts by using a naphthalene sublimation technique. The corrugation angles of the wavy ducts are $145^{\circ}$ , $130^{\circ}$ and $115^{\circ}$ . and the Reynolds numbers based on the duct hydraulic diameter vary from 300 to 3,000. At the low $Re(Re{\leq}1000)$, high heat/mass transfer regions are formed by the secondary vortex flows called Taylor-Gortler vortices on both pressure-side and suction-side walls. At the high $Re(Re{\geq}1000)$, the effects of these secondary flows are vanished. As corrugation angle decreases, the local peak Sh induced by Taylor-Gertler vortices are increased and average Sh also enhanced. More pumping power (pressure loss) is required with the smaller corrugation angle due to the stronger secondary vortex flows.