• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.7
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• pp.7-13
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• 2001

The wirebonding is a common interconnection technique for modern microwave devices because of rather simple and reliable processes involved. At millimeter-wave frequencies, however, the bondwire parasitics are significant and consequently limit the external performance of packaged devices. In this paper, we represent wideband characterization of multiple bondwires and ribbon in a frequency range from 20 to 35 GHz. From these results, the double bondwire shows very small insertion loss less than 0.55 dB up to 35 GHz and its performance is comparable to that of the ribbon in the millimeter-wave frequencies. Therefore, the wirebonding is very suitable for millimeter wave packaging in terms of performance and manufacturing cost.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.121-127
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• 2010

An experimental study of composite beam with perforated fiber reinforced polymer(FRP) plank as a permanent formwork and the tensile reinforcement was performed. A combined formwork and reinforcement system can facilitate rapid construction of concrete members since no conventional formwork is needed, which requires time consuming assembly and dismantling. In order for a smooth FRP plank to act compositely with the concrete, the surface of the FRP needs to be treated to increase its bond properties. Aggregates were bonded to the FRP plank using a commercially available epoxy and perforated web of plank. No additional flexural or shear reinforcement was provided in the beams. For comparison, two control specimens were tested. One control had no perforated hole in the web of FRP plank and the other had internal steel reinforcing bars instead of the FRP plank. The beams were loaded by central patch load to their ultimate capacity. This study demonstrates that the perforated FRP plank has the potential to serve as a permanent formwork and reinforcing for concrete beam.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.60_61
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• 2009

최근 국내에서 345kV GIL(Gas Insulated Transmission Lines) 시스템의 실 계통 도입이 검토되고 있다. 현재까지 GIL은 원자력 발전소에서 주변압기로부터 스위치 야드까지 1km 미만의 거리에 소규모로 설치되어 운영되고 있다. 하지만 향후 본격적으로 GIL 시스템이 도입된다면 발전소 구내뿐만 아니라 수 km 이상 되는 송전급 선로에도 적용될 것이 예상된다. 현재 GIL의 시스(외함)는 100~120m 정도마다 접지를 하는 직접접지 형태를 취하고 있으나 시스에 흐르는 순환전류가 부하전류의 97% 이상 된다. 따라서 이에 따른 손실이 많이 발생되고 있어 도체에 흘릴 수 있는 허용전류 값이 감소하게 된다. 본 논문에서는 GIL 시스템에 크로스본드 접지방식을 적용하였을 때 시스 순환전류 감소 효과에 대해서 검토하고, 아울러 뇌써지나 스위칭 써지에 의한 절연통의 열화 등에 대비하기 위하여 절연통보호장치의 설치 방안에 대해서 검토하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.66-75
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• 1998

In many case of optimal design and sensitivity analysis, obtaining of transfer function between input and output variables is a difficult and time-consuming problem. The bond graph modeling is a method that is used for making it easy to analyze complex systems composed of mechanical and electrical parts. It gives us a simple and systematic tool to get state-space equations easily. And we can obtain the transfer function graphically using bond graph and Mason's rule. This paper shows how bond graphs are converted to block diagram and how Mason's rule is applied. And the simple direct method to obtain transfer function from bond graph is introduced. As a example, induction of transfer function of electric power steering composed of mechanical and electrical parts will be done.

• Composites Research
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• v.19 no.5
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• pp.34-39
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• 2006

The mechanical properties and durabilities of fiber advanced composites make them ideal for widespread applications in construction worldwide. However, one of the problems of fiber reinforced advanced composites has expensive initial costs. So the efforts for lowering the initial cost have to be needed. There has been hardly assessment results of life cycle cost for fiber reinforced advanced composites in construction field, but some papers showed that total life cycle cost could be profitable, if the initial cost could be reduced. The purpose of this paper is to report assessment results of LCC(Life Cycle Cost) for application of FRP(Fiber Reinforced Plastic) in construction field.

• Journal of Preventive Medicine and Public Health
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• v.26 no.2 s.42
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• pp.222-230
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• 1993

Industrial glues, known as 'Bonds' in Korea, contain many kinds of organic solvents, and glue sniffing of youths became one of the social problems in Korea. Mixed exposures to solvents by glue sniffing may induce chronic toxicities different from those by exposures to solvents of single component. To test effects of the glue sniffing on weight gain or central nervous system, two groups of 20 male Sprague-Dawley rats were exposed to air(control group) or vapors of the glues to narcotic status(exposed group), and weight check, tail flick test, hot plate test, rotarod treadmill test were done on the 14th,24th, 36th, 45th, 53rd, 86th, 102nd, 117th, 134th and 151st days after the first exposure. On the 188th day, their brains were excised and examined by a pathologist. Weight gain, controlled against time change, showed significant difference between the groups, but response times in tail flick test, hot plate tests, and rotarod treadmill test didn't. In pathological examination with blind method, no macroscopic or microscopic differences were found between the two groups. These results suggests that organic lesion in central nervous system may not ensue glue sniffing, but, before firm conclusion, more studies in various exposure conditions should be followed.

• KDI Journal of Economic Policy
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• v.32 no.1
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• pp.1-26
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• 2010

Securitization was meant to disperse credit risk to those who were better able to bear it. In practice, securitization appears to have concentrated the risks in the financial intermediary sector itself. This paper outlines an accounting framework for the financial system for assessing the impact of securitization on financial stability. If securitization leads to the lengthening of intermediation chains, then risks become concentrated in the intermediary sector with damaging consequences for financial stability. Covered bonds are one form of securitization that do not fall foul of this principle. I discuss the role of countercyclial capital requirements and the Spanish-style statistical provisioning in mitigating the harmful effects of lengthening intermediation chains. For Korea, the stability of funding emerges as a key consideration. Covered bonds may play a role in stabilizing the funding arrangement for banks.

• Journal of the Korean Magnetics Society
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• v.4 no.3
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• pp.219-225
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• 1994

The alignment of Sr-ferrite magnetic powders, which is usually related to the fluidity and the applied magnetic field, is investicated in the anisotropic Sr-ferrite / resin-bonded permanent magnets. The magnetic powder alignment is observed to increase with the applied magnetic field and the fluidity which is a function of molding temperature and powder packing ratio. The best magnetic powder alignment is achieved at the following conditions; Sr-ferrite packing ratio of 56vol%, apparent viscosity of about 3000 poise in $1000sec^{-1}$ shear rate, and applied magnetic field of about 5kOe. The degree of preferred orientation of the magnetic powders in the field direction, as determined by the dc hysterisis graphs, is 84~85% (0.84~0.85). This result is in agreement with the value of 0.85 obtained by the X-ray experiments in the $2{\theta}$ range of ${23~40}^0$. The best magnetic properties obtained are:2.2kG of remanent flux density, 2.2MGOe of maximum energy product.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.19-26
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• 2004

High performance packages must provide excellent transmission characteristics. In face-up ceramic packages, however, parasitic characteristics of bondwires are not negligible at millimeter-wave frequencies. Consequently, the electrical performance of ceramic packages is degraded. In をis paper, we propose a new millimeter-wave ceramic package feed-through having Embedded Metal Sheets (EMS). The package that contains double-bondwire interconnections is analyzed by the FEM (Finite Element Method) and measured from 20 to 50GHz. As a result, the proposed package having Embedded Metal Sheets (EMS) achieved 0.85dB, 0.4dB insertion loss improvement on the conventional and the double bondwires buried in epoxy ( $\varepsilon_{{\gamma}}$/ = 4) ceramic package respectively to 47GHz. This improved ceramic package will be useful for MMICs modules and small ceramic packages developments.amic packages developments.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.119-119
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• 2018

1992년 '자원절약과 재활용 촉진에 관한 법률'이 제정되었고 폐기물 관련 규제가 강화됨에 2003년 생산자 책임 재활용 제도(EPR)를 도입하였다. 하지만 비데시트 내부에 부착된 열선의 누전방지를 위하여 은박지 및 비데 상하면을 강력본드로 접합시키고 있다. 이 점이 재활용에 많은 어려움으로 되어 일부는 재활용되거나 폐기되고 있는 실정이다. 이러한 유효자원이 폐기되고 있는 문제점을 해결하기 위한 방안으로서 열선과 플라스틱을 자동분리 할 수 있는 장치(지그)를 개발함으로써 효율적인 R&D 사업을 제시하고 문제점을 해결할 수 있다. 이에 가정이나 생활현장에서 폐기되고 있는 자원을 회수할 수 있는 기술을 제공하고자 한다. 본고에서는 필자가 현장에서 근무하면서 터득한 폐기되고 있는 생활 폐기물인 비데두껑을 이용한 환경개선과 소재활용을 목표로 열선과 플라스틱 수지를 효과적으로 분리시킬 수 있는 기술을 적용시킴으로써 수입 대체 소재 재활용 국산에 이바지 하고자 하였다.