• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.949-953
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• 1999

Because epoxy molding compound(EMC) for semi-conductor encapsulants contains high concentrations of fillers, its flow behaviors are affected much by the concentrations and properties of those fillers. This paper reports the effects of a filler concentration, shape, size, and size distributions on the viscosity behavior of EMC(epoxy/silica). In addition, the prediction of viscosity behavior was performed using the Mooney equation. The maximum packing volume in the Mooney equation was calculated by Ouchiyama's packing model and Taguchi's optimization method, while the shpae factor was determined by fitting the experimental data. The results showed that the Mooney equation predicted the viscosity behavior of EMC very well.

• Korea Journal of Hospital Management
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• v.10 no.2
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• pp.64-80
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• 2005

The objectives of this study were to identify factors associated with unexpected revisit to an emergency medical center (EMC) located in Seoul and to examine reasons for revisit. During March, June, September and December, 2002, a total of 168 patients had unexpected revisits to the EMC within 48 hours of a previous discharge. As a 1:1 matched control, we included 136 patients who: discharged from the EMC during the same time period: did not return to the EMC; had the same diagnosis and age(${\pm}5$) with the case. In this study, factors associated with unexpected revisits were defined as characteristics of a previous discharge, which were classified into three: sociodemographic, EMC visit-related, and discharge management factors. Reasons for revisit were categorized into disease, physician, patients, and system-related factors. Data were collected by medical chart review with assistance from clinicians of the EMC. Logistic regression results showed that patients who headed home after discharge without follow-up schedule had a 27.6 times higher risk of revisiting EMC than those who were hospitalized following EMC visit. Patients discharged on his own will had a 5.9 times higher risk of revisiting than those discharged following physician's advice. Patients requiring continual observation at the time of discharge were more likely to revisit by 8.7 times than those discharged with improved condition. About 69.13% of the revisits were due to disease-related factors, followed by 13.90% due to patient-related factors, 8.64% due to system-related factors, and 8.34% due to physician-related factors. It appears that the most significant factors influencing revisits are discharge management factors such as patient's condition at discharge, whether the discharge was accorded with physician's advice, and whether returning home without follow-up schedule. Therefore, appropriate discharge management is necessary to prevent EMC revisit.

• Journal of Navigation and Port Research
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• v.28 no.8
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• pp.715-719
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• 2004

This paper deals with EMC filter for a personal computer(PC). A PC contains many sources of noise inside and out, with many connected cables. High noise levels are also emitted from the PC because of high-speed signals. So radiated noise from the computer body may sometimes cause problems. Therefore, we design and fabricate an electromagnetic compatibility (EMC) filter for PC, which is composed of feed-through capacitors and ferrite beads with high permeability. Through extensive test, the proposed EMC filter is shown to have excellent differential-mode and common-mode noises filtering characteristics above 30 dB in the frequency band from 10 MHz to 1.5 GHz. The immunity characteristics are improved more than 10 to 30 dB over the frequency band from DC to 1.8 GHz.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.8
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• pp.322-328
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• 2006

In this paper, The impulse un-tripping characteristics and the electro magnetic compatibility characteristics are compared with each other. The performance of impulse un-tripping test exists at domestic standard (KSC 4613). However test items are insufficient because the more test items such as EMC exist at international standard (IEC). Also, Electric Appliances Safety Certificate has taken the certificate test since July 2004 in Korea but did not confirm the EMC performance for RCCBs made in Korea. Thus, in this paper, We experiment with Oscillatory waves immunity test and the 7 EMC tests for 32 RCCBs of 4 types (mini, home standard, plug, outlet) for 16 brands according to IEC standard 61009-1 and 61008-1. As a result, 24 RCCBs proved to be poor for surge immunity test. However the RCCBs operating incorrectly for surge immunity test operate correctly for oscillatory waves immunity test. Thus, the correlation between oscillatory waves immunity test and EMC test is little and standard for compatibility of combination surge at IEC 61000-4-5 should be added to KS standard as soon as possible.

• Korean Journal of Materials Research
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• v.7 no.9
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• pp.781-788
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• 1997

Cu/EMC 계면 접착력에 미치는 산화의 규명하기 위해 리드프레임의 저온 산화에 대하여 조사하였다. 이전의 보고와 달리, 저온에서도 Cu$_{2}$O위에 CuO산화물이 형성되어 Cu/Cu$_{2}$O(NiO)/Cu(NiO)/air의 산화층 구조를 나타내었다. Cu/EMC 계면 접착력은 산화가 진행됨에 따라 산화 초기에 급격히 증가하다 최대값에 이르고, 이후의 계속적인 산화로 감소하는 양상을 보였다. 접착력은 산화 온도나 리드프레임의 종류보다 산화막의 두께에 밀접한 상관 관계를 나타내었다. 최대 계면 접착력이 얻어지는 산화막의 두께는 리드프레임의 종류보다 산화막의 두께에 밀접한 상관 관계를 나타내었다. 최대 계면 접착력이 얻어지는 산화막의 두께는 리드프레임의 종류와 무관하게 대략 20nm 와 30nm 사이에 존재하였다. 산화 초기의 접착력 증가는 산화로 인한 EMC에 대한 젖음성의 증가와 기계적 고착 효과의 증가에 기인하였다. 리드프레임과 EMC의 파괴 표면에 대한 AES, XPS 분석으로 부터, 산화막의 두께가 얇을 때에는 Cu$_{2}$O//CuO의 계면 파괴 + EMC 자체 파괴가 복합적으로 발생함을 알 수 있었다. 반면에 과도한 산화로 낮을 접착력을 나타내는 시편은 Cu/Cu$_{2}$/O 계면의 파괴를 나타냈다.

• Structural Engineering and Mechanics
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• v.75 no.5
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• pp.559-569
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• 2020

In the present study, the fracture toughness of U-shaped notches made of aluminum alloy Al7075-T6 under combined tension/out-of-plane shear loading conditions (mixed mode I/III) is studied by theoretical and experimental methods. In the experimental part, U-notched test samples are loaded using a previously developed fixture under mixed mode I/III loading and their load-carrying capacity (LCC) is measured. Then, due to the presence of considerable plasticity in the notch vicinity at crack initiation instance, using the Equivalent Material Concept (EMC) and with the help of the point stress (PS) and mean stress (MS) brittle failure criteria, the LCC of the tested samples is predicted theoretically. The EMC equates a ductile material with a virtual brittle material in order to avoid performing elastic-plastic analysis. Because of the very good match between the EMC-PS and EMC-MS combined criteria with the experimental results, the use of the combination of the criteria with EMC is recommended for designing U-notched aluminum plates in engineering structures. Meanwhile, because of nearly the same accuracy of the two criteria and the simplicity of the PS criterion relations, the use of EMC-PS failure model in design of notched Al7075-T6 components is superior to the EMC-MS criterion.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.207-212
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• 2008

In EMC(electromagnetic compatibility) certification, the facilities and equipments have been considered as important qualification for registration of EMC certification business. In future, the certification environment is also supposed to be restricted Strictly. Many organizations have made on attempt to establish, certification environment as a international standard. Therefore, in order to enhance the competitive powers of domestic certification industry, a real-time system which can be measure automatically and remotely the temperature, humidity, illumination, CO/CO2, magnetic field, and human sensing is proposed in this paper. This system can also maintain the appropriate measurement environment by using USN (ubiquitous sensor network). The availabilities are confirmed through the experiment.

• Journal of Power Electronics
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• v.18 no.1
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• pp.195-203
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• 2018

In the variable speed Wind Turbine based on ElectroMagnetic Coupler (WT-EMC), a synchronous generator is coupled directly to the grid. Therefore, like conventional power plants, WT-EMC is able to inherently support grid frequency. However, due to the reduced inertia of the synchronous generator, WT-EMC is expected to be controlled to increase its output power in response to a grid frequency drop to support grid frequency. Similar to the grid frequency support control of Type 3 or Type 4 wind turbine, inertial control and droop control can be used to calculate the WT-EMC additional output power reference according to the synchronous generator speed. In this paper, an experimental platform is built to study the grid frequency support from WT-EMC with inertial control and droop control. Two synchronous generators, driven by two induction motors controlled by two converters, are used to emulate the synchronous generators in conventional power plants and in WT-EMCs respectively. The effectiveness of the grid frequency support from WT-EMC with inertial control and droop control responding to a grid frequency drop is validated by experimental results. The selection of the grid frequency support controller and its gain for WT-EMC is analyzed briefly.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.1
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• pp.14-21
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• 1996

전자기적합성 전문위원회(TC 77 : Electromagnetic Compatibility)는 현재 IEC/TC중 에서 가장 활동이 활발한 TC 가운데 하나이다. 이는 거의 모든 산업 분야에 중요한 문제로 대두 되고 있는 EMC의 표준화를 담당하고 있기 때문이다. 이 글에서는 IEC/TC 77의 배경 및 업무 등 을 간단히 살펴 보고, EMC 표준화 전반에 걸쳐 관련되고 모든 EMC 규격의 바탕이 되는 '기본 E MC 간행물(IEC 1000 시리스)'의 현황을 알아 본다. 여기서는 IEC 1000 시리스 외에도 EMC 관련 이 많은 CISPR 규격 등 몇개를 포함시켰으나, SC 77C(HEMP) 관련 규격은 생략하였다.

• Electronics and Telecommunications Trends
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• v.33 no.3
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• pp.41-50
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• 2018

In order to ensure the electromagnetic safety of a complex facility equipped with a variety of electric and electronic equipment, the European Union (EU) has enacted and applied the Electromagnetic Compatibility Directive (EMC Directive 2004/108/EC) to a fixed installation. This paper introduces the regulations and techniques related with electromagnetic compatibility (EMC) engineering applied to a fixed installation, which is used to prevent a malfunction of critical equipment and systems caused by unwanted electromagnetic waves and to operate the facilities with stability.