• 한국생산제조학회지
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• 제7권1호
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• pp.22-33
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• 1998

A continuum analysis of the evolution of plasticity and Bauschinger effect in a short fiber reinforced metal matrix composite, based on the FEM solution for a single fiber model has been performed to investigate the strengthening behavior. The evolution of matrix field quantities during one cycle of fully reversed loading have been examined in detail. The results indicate that the role of constrained matrix flow in generating different levels of matrix triaxiality during forward and reversed loading provides an important contribution to the developement of the Bauschinger effect in the metal matrix composite. Therefore, even when the plastic flow of the matrix material follows on isotropic hardening behavior, the Bauschinger effect is predicted for the composite material.

• 한국진공학회지
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• 제1권1호
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• pp.115-120
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• 1992

SIMS는 뛰어난 원소검출감도와 깊이 분해능을 가지고 있어서 깊이에 따른 미량불 순물 분석에 필수적인 장비이지만, 시료와 불순물의 변화에 따라 이온화율과 깍이는 속도가 달라서 일어나는 matrix effect 때문에 표준 시료없이 정량분석을 할 수 없는 문제점이 있 다. 이런 SIMS의 단점을 보완하기 위한 방법으로 개발된 여러 가지 SNMS 기술 중 SIMS에 아무런 기계장치를 덧붙이지 않고도 정량화 개선효과를 가져오는 CsX+ SNMS에 대한 연구 를 진행하여, 지금까지 밝혀진 실리콘 산화막 등에서의 주성분원소 조성비분석을 통해 SNMS 기능을 확인하고 SIMS의 주 분석대상인 분순물 농도분석에의 적용가능성을 실험해 보았다. 이를 위해 실리콘에 BF2 이온 주입 후 붕소분포 분석시 강한 matrix effect를 나타 내는 불소의 효과를 SNMS와 SIMS로 비교하였으며, 검출한계와 dynamic range도 조사하였 다. 실험결과 CsX+ SNMS 기술은 matrix effect 때문에 실제분포와 다른 값으로 검출되는 불순물 시료분석에 적용할 수 있음을 알았다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1992년도 제2회 학술발표회 논문개요집
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• pp.17-18
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• 1992

SIMS는 뛰어난 원소검찰감도의 깊이분해능을 가지고 있어서 깊이에 따른 미량불순물 분석에 필수적인 장비이지만, 시료와 불순물의 변화에 따라 이온화율과 깎이는 속도가 달라서 일어나는 matrix effect 때문에 표준시료없이 정량분석을 할 수 없는 문제점이 있다. 이런 SIMS의 단점을 보완하기 위한 방법으로 개발된 여러 가지 SNMS기술중 SIMS에 아무런 기계장치를 덧붙이지 않고도 정량화개선효과를 가져오는 CsX+ SNMS에 대한 연구를 진행하여, 지금까지 밝혀진 실리콘 산화막등에서의 주성분원소 조성비분석을 통해 SNMS기능을 확인하고 SIMS의 주 분석대상인 불순물농도분석에의 적용가능성을 실험해 보았다. 이를 위해 실리콘에 BF2 이온주입후 붕소분포분석시 강한 matrix effect를 나타내는 불소의 효과를 SNMS와 SIMS로 비교하였으며, 검출한계와 dynamic range도 조사하였다. 실험결과 CsX+ SNMS기술은 matrix effect 때문에 실제 분포와 다른 값으로 검출되는 불순물 시료 분석에 적용할 수 있음을 알았다.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3482-3488
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• 2014

Matrix-induced mass bias and its effect on the accuracy of isotope ratio measurements have been examined for a quadrupole-based inductively coupled plasma-mass spectrometer (Q ICP-MS). Matrix-induced mass bias effect was directly proportional to % mass difference, and its magnitude varied for element and nebulizer flow rate. For a given element and conditions in a day, the effect was consistent. The isotope ratio of Cd106/Cd114 under $200{\mu}g\;g^{-1}$ U matrix deviated from the natural value significantly by 3.5%. When Cd 111 and Cd114 were used for the quantification of Cd with isotope dilution (ID) method, the average of differences between the calculated and measured concentrations was -0.034% for samples without matrix ($0.076{\mu}g\;g^{-1}$ to $0.21{\mu}g\;g^{-1}$ for the period of 6 months). However, the error was as large as 1.5% for samples with $200{\mu}g\;g^{-1}$ U. The error in ID caused by matrix could be larger when larger mass difference isotopes are used.

• Computers and Concrete
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• 제15권3호
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• pp.373-389
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• 2015

The development of a finite element model for the geometric and material nonlinear analysis of bonded prestressed concrete continuous beams is presented. The nonlinear geometric effect is introduced by the coupling of axial and flexural fields. A layered approach is applied so as to consider different material properties across the depth of a cross section. The proposed method of analysis is formulated based on the Euler-Bernoulli beam theory. According to the total Lagrangian description, the constructed stiffness matrix consists of three components, namely, the material stiffness matrix reflecting the nonlinear material effect, the geometric stiffness matrix reflecting the nonlinear geometric effect and the large displacement stiffness matrix reflecting the large displacement effect. The analysis is capable of predicting the nonlinear behaviour of bonded prestressed concrete continuous beams over the entire loading stage up to failure. Some numerical examples are presented to demonstrate the validity and applicability of the proposed model.

• 한국재료학회지
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• 제25권12호
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• pp.678-682
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• 2015

The electrical property of polymer matrix composites with added carbon powder is studied based on the temperature dependency of the conduction mechanism. The temperature coefficient of the resistance of the polymer matrix composites below the percolation threshold (x) changed from negative to positive at 0.20 < x < 0.21; this trend decreased with increasing of the percolation threshold. The temperature dependence of the electrical property(resistivity) of the polymer matrix composites below the percolation threshold can be explained by using a tunneling conduction model that incorporates the effect of the thermal expansion of the polymer matrix composites into the tunneling gap. The temperature coefficient of the resistance of the polymer matrix composites above the percolation threshold has a positive value; its absolute value increased with increasing volume fraction of carbon powder. By assuming that the electrical conduction through the percolating paths is a thermally activated process and by incorporating the effect of thermal expansion into the volume fraction of the carbon power, the temperature dependency of the resistivity above the percolation threshold can be well explained without violating the universal law of conductivity.

• Journal of Welding and Joining
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• 제16권1호
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• pp.114-124
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• 1998

The effect of matrix phase (austenite, pearlite, martensite) on the low stress abrasion resistance in the chromium-carbide-type high Cr white iorn hardfacing weld deposites has been investigated. In order to examine matrix phase, a series of alloys with different matrix phase by changing the ratio of Cr/C system by heat treatment were employed. The alloys were deposited twice on a mild steel plate using self-shielding flux cored arc welding process. The low stress abrasion resistance of the alloys against sands was measured by the Dry Sand/Rubber Wheel Abrasion Test(RWAT). Even though formation of pearlite phase in the matrix showed higher hardness than that of austenite, there was no observable difference in wear resistance between the pearlite and austenite phase for the same amount of chromium-carbide in the matrix. On the other hand, the formation of martensitic phase,, from heat treated austenitic alloys (high content of Cr), enhanced wear resistance due to its fine secondary precipitates.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1258-1266
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• 2005

The present study was carried out in order to assess the protective effects of calycosin-7-O-$\beta$-D-glucopyranoside, isolated from Astragali radix (AR), on hyaluronidase (HAase) and the recombinant human interleukin-$1\beta$ (IL-$1\beta$)-induced matrix degradation in human articular cartilage and chondrocytes. We isolated the active component from the n-butanol soluble fraction of AR (ARBu) as the HAase inhibitor and structurally identified as calycosin-7-O-$\beta$-D-glucopyranoside by LC-MS, IR, ${1}^H$ NMR, and ${13}^C$ NMR analyses. The $IC_{50}$ of this component on HAase was found to be 3.7 mg/ml by in vitro agarose plate assay. The protective effect of ARBu on the matrix gene expression of immortalized chondrocyte cell line C28/I2 treated with HAase was investigated using a reverse transcription polymerase chain reaction (RT-PCR), and its effect on HAase and IL-$1\beta$-induced matrix degradation in human articular cartilage was determined by a staining method and calculating the amount of degraded glycosaminoglycan (GAG) from the cultured media. Pretreatment with calycosin-7-O-$\beta$-D-glucopyranoside effectively protected human chondrocytes and articular cartilage from matrix degradation. Therefore, calycosin-7-O-$\beta$-D-glucopyranoside from AR appears to be a potential natural ant-inflammatory or antii-osteoarthritis agent and can be effectively used to protect from proteoglycan (PG) degradation.

• 한국통신학회논문지
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• 제36권8A호
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• pp.741-747
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• 2011

잘 알려진 매트릭스 팬슬 방법은 정적이지 않은 환경 및 주파수가 같은 다중경로 신호가 존재 할때도 동작하는 입사각 추정방식이다. 매트릭스 팬슬방식은 기존의 공분산행렬을 사용한 방식보다 더 좋은 분해능을 보여 줄뿐 아니라 계산량의 측면에서도 매우 효과적이다. 본 논문에서는 매트릭스 팬슬 방식의 계산 과정에서 발생되는 데이터의 가중치가 균형이 맞지 않음으로써 생기는 영향에 관해 기술한다. 데이터의 균형이 맞는 새로운 방식의 매트릭스 팬슬 방식을 제안하고 데이터의 불균형을 해소할 수 있음을 보여주었다.

• 수산해양기술연구
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• 제51권4호
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• pp.561-566
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• 2015

In this study, the effect of temperature effect of the rubber matrix filled with nano sized silica particles composites with silica volume fraction of 19-25% was investigated by the Charpy impact test. The Charpy impact test was conducted in the temperature range from $-40^{\circ}C$ to $0^{\circ}C$. The critical energy release rate GIC of the rubber matrix composites filled with nano sized silica particles was considerably affected by temperature and it was shown that the maximum value was appeared at higher temperature between temperature tested and it was shown that the value of GIC increases as temperature tested increases. The major fracture mechanisms were matrix deformation, silica particle debonding and delamination, microcrack between particles and matrix, and/or pull out between particles and matrix which is ascertained by SEM photographs of Charpy impact surfaces fracture.