• Steel and Composite Structures
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• v.1 no.3
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• pp.355-376
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• 2001

An experimental research program on end-plate beam-to-column composite joints under cyclic loading is presented. The major focus relates to the identification of the contribution of the concrete confinement in composite columns to the behaviour of the joint, on internal nodes and external nodes, together with an assessment of degradation of strength and stiffness in successive loading cycles. From the experimental results it was possible to identify the various failure modes and to fit the corresponding hysteretic curves to the Richard-Abbott and Mazzolani models. These curve-fitting exercises highlighted the need to adapt both models, either for improved ease of application, or to deal with some aspects previously not covered by those models.

• Computers and Concrete
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• v.19 no.3
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• pp.227-232
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• 2017

This paper describes an experimental study of the cyclic performance of concrete beams reinforced with CFRP prestressed concrete prisms (PCP). The failure modes, hysteretic loops, skeleton curve, ductility, energy dissipation capacity and stiffness degradation of concrete beams reinforced with CFRP prestressed concrete prisms were analyzed. The results show that The CFRP prestressed prisms reinforced concrete beams have good seismic performance. The level of effective prestress and cross section of CFRP prestressed prisms had a little influence on the bearing capacity, the ductility and energy dissipation capacity of CFRP prestressed prisms reinforced concrete beams.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.970-973
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• 1999

When the size of the device is decreased, the hot carrier degradation presents a severe problem for long-term device reliability. In this paper we fabricated & tested the 0.26${\mu}{\textrm}{m}$ NMOSFET with wet gate oxide and nitride oxide gate to compare that the characteristics of hot carrier effect, charge to breakdown, transistor Id_Vg curve and charge trapping using the Hp4145 device tester As a result we find that the characteristics of nitride oxide gate device better than wet gate oxide device, especially a hot carrier lifetime(nitride oxide gate device satisfied 30years, but the lifetime of wet gate oxide was only 0.1year), variation of Vg, charge to breakdown and charge trapping etc.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.483-488
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• 2001

Until now, the tensile properties of materials can be obtained just in accordance with conventional tensile testing methods which are described in several standards such as ASTM (American Society for Testing and Materials) standard and BS (British Standard). For some cases including on-service facility materials, however, the standard testing methods cannot be applicable due to the destructive testing procedure and specimen size requirement. Therefore, simple, non-destructive and advanced indentation technique was proposed. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. In this paper, the research trend of non-destructive evaluation of tensile properties using AIS (advanced indentation system) and its application fields are reviewed and discussed.

• Progress in Superconductivity
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• v.3 no.2
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• pp.146-150
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• 2002

We performed the point contact spectroscopy on newly discovered superconductor $MgB_2$ thin films with Au tip. In the point contact spectroscopy of the metallic Sharvin limit, the differential conductance below the gap is twice as that above the gap by virtue of Andreev Reflection. After some surface cleaning processes of sample preparation such as ion-milling and wet etching, the obtained dI/dV versus voltage curves are relatively well fitted to the Blonder-Tinkham-Klapwijk (BTK) formalism. Gaps determined by this technique were distributed in the range of 3meV~ 8meV with the BCS value of 5.9meV in the weak coupling limit. We attribute these discrepancies to the symmetry of the gap parameter and the degradation of the surface of the sample. We also present the temperature dependence of the conductance vs voltage curve and thereby the temperature dependence of the gap.

• KSTLE International Journal
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• v.1 no.1
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• pp.48-51
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• 2000

Surface damage accumulation of alumina ceramics under the cyclic stress state was analyzed. The alternating stress state in repeat pass sliding contact was simulated by a synchronized biaxial (normal and tangential) repeated indentation technique. Wear debris formation mechanism through damage accumulation and fatigue grain failure in both alumina ceramic balls and flat disks was confirmed, and the contact induced surface degradation due to fatigue cracking accumulation was quantified by measuring vertical contact displacement. Variation of structural compliance (slope of load-displacement curve) of two contacting bodies was expressed as a variation of the apparent elastic property, called pseudo-elastic constant, of the contact system.

• Environmental and Resource Economics Review
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• v.16 no.3
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• pp.629-641
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• 2007

Chinese government has implemented the West Development Strategy since 1999 to boost the region's growth and prevent the environmental degradation. Until now, the regional economy and living standard in Western China have been greatly improved, while it also indicated by the State Council that the ecological environment still deteriorated with part improvement, and pressure of water shortage increased. The paper focus on the relationship of GDP per capita and the volume of industrial waste water discharge of all the 12 provinces in Western China from 1989 to 2004, by the expanded EKC model in the cubic form. Results show that they mainly have down trend in the whole sample space but small up trend in the recent years. That means controlling of industrial wastewater discharge is still an important task to be insisted in the Western China.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.500-509
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• 2015

This paper presents the single objective design optimization of plate-fin heat sink equipped with fan cooling system using Genetic Algorithm. The proper heat sink and fan model are selected based on the previous studies. And the thermal resistance of heat sinks and fan efficiency during operation are calculated according to specific design parameters. The objective function is combination of thermal resistance and fan efficiency which have been taken to measure the performance of the heat sink. And Decision making procedure is suggested considering life time of semiconductor and Fan Operating cost. And also Analytical Model used for optimization is validated by Fluent, Ansys 13.0 and this model give a quite reasonable and reliable design.

• Journal of the Korean Electrochemical Society
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• v.21 no.2
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• pp.21-27
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• 2018

In this review, recent researches on ion transport phenomena in organic metal halide perovskite materials, which have been popular all over the world, are summarized. Although different results have been reported depending on the perovskite material composition and applied voltage, iodide seems to migrate under actual solar cell operating conditions, and occasionally methylammonium migration is observed. Perovskite is a so-called mixed conductor in which electrons and ions move simultaneously at room temperature, which greatly influences the hysteresis of the perovskite solar cell current-voltage curve and the performance degradation due to long-term operation.

• Elastomers and Composites
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• v.30 no.2
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• pp.105-111
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• 1995

The thermal decomposition of the paper sludge with poly (acrylonitrile-butadiene-styrene) was using a thermal analysis techniques in the stream of nitrogen gas of 30ml/min at various heating rates from 4 to $20^{\circ}C/min$. The mathmatical, derivative and integral method were used to obtain values of activation energy of decomposition reaction. 1. The values of activation energy evaluated by derivative and Intergral method were consistent with each other very well. 2. The maximum value of heat of decomposition evaluated by DSC method was 10.120cal/g at weight ratio of paper sludge/ABS=20/80. 3. The thermogravimetric trace curve agreed with the theoretical equation.