• Tribology and Lubricants
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• v.21 no.2
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• pp.71-76
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• 2005

This paper compares of mechanical tensile properties of 6 kinds of copper foil. The beam lead made with copper foil. Different from other package type such as plastic package, Chip Size Package has a reliability problem in beam lead rather than solder joint in board level. A new tensile loading system was developed using voice-coil actuator. The new tensile loading system has a load cell with maximum capacity of 20 N and a non-contact position measuring system based on the principle of capacitance micrometry with 0.1nm resolution for displacement measurement. Strain was calculated from the measured displacement using FE analysis. The comparison of mechanical properties helps designer of package to choose copper for ensuring reliability of beam lead in early stage of semiconductor development.

• Korean Journal of Crystallography
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• v.12 no.2
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• pp.102-112
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• 2001

The mechanical properties of silicon crystals are important from the viewpoint of wafer and device fabrication processes. It is now widely recognized that silicon undergoes a series of phase transformations when subjected to high pressures, using conventional high pressure devices, such as diamond anvils or indenters. Diamond tip scratching on a silicon surface in the various conditions introduces various kinds of mechanical damage and stressed states. Micro Raman spectroscopy was used to observe the phase transition of single crystal silicon. As results, different morphologies were observed as functions of scratching speed and loading condition and various phases were observed as functions of scratching speed and loading condition.

• Journal of Electrochemical Science and Technology
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• v.7 no.3
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• pp.218-227
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• 2016

The light harvesting efficiency is counted as an important factor in the power conversion efficiency of DSSCs. There are two measures to improve this parameter, including enhancing the dye-loading capacity and increasing the light trapping in the photoanode structure. In this paper, these tasks are addressed by introducing a macro-porous silicon (PSi) substrate as photoanode. The effects of the novel photoanode structure on the DSSC performance have been investigated by using energy dispersive X-ray spectroscopy, photocurrent-voltage, UV-visible spectroscopy, reflectance spectroscopy, and electrochemical impedance spectroscopy measurements. The results indicated that bigger porosity percentage of the PSi structure improved the both anti-reflective/light-trapping and dye-loading capacity properties. PSi based DSSCs own higher power conversion efficiency due to its remarkable higher photocurrent, open circuit voltage, and fill factor. Percent porosity of 64%, PSi(III), resulted in nearly 50 percent increment in power conversion efficiency compared with conventional DSSC. This paper showed that PSi can be a good candidate for the improvement of light harvesting efficiency in DSSCs. Furthermore, this study can be considered a valuable reference for more investigations in the design of multifunctional devices which will profit from integrated on-chip solar power.

• Membrane and Water Treatment
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• v.5 no.3
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• pp.183-195
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• 2014

The efficiency of two metal ions (cadmium, zinc) removal from aqueous solutions by ultrafiltration (UF) and Polymer Enhanced Ultrafiltration (PEUF) processes were investigated in this work. The UF and PEUF studies were carried out using an ultrafiltration tangential cell system equipped with 5.000 MWCO regenerated cellulose. A water-soluble polymer: the polyacrylic acid (PAA) was used as complexant for PEUF experiments. The effects of transmembrane pressure, pH, metal ions and loading ratio on permeate fluxes and metal ions removals were evaluated. In UF process, permeate fluxes increase linearly with increasing pH for different transmembrane pressure, which may be the consequence of the formation of soluble metal hydroxyl complexes in the aqueous phase. In PEUF process, above pH 5.0, the Cd(II) retention reaches a plateau at 90% and Zn(II) at 80% for L = 5. Also, cadmium retention at different L is greater than zinc retention at pH varying from 5.0 to 9.0. In a mixture solution, cadmium retention is higher than zinc for different loading ratio, this is due to interactions between carboxylic groups of PAA and metal ions and more important with cadmium ions.

• Journal of Pharmaceutical Investigation
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• v.34 no.4
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• pp.275-281
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• 2004

We have studied the effect of polarity, current density, current duration, crosslinking density, swelling ratio, and permeation enhancers on the transdermal flux of ketoprofen from acrylamide hydrogel. Hydrogel was prepared by free radical crosslinking polymerization of acrylamide. Drug loading was made just before transport experiment by soaking the hydrogel in solution containing drug. In vitro flux study using hairless mouse skin was performed at $36.5^{\circ}C$ using side-by-side diffusion cell, and the drug was analysed using HPLC/UV system. The result showed that, compared to passive flux, the total amount of drug transported increased about 18 folds by the application of $0.4\;mA/cm^2$ cathodal current. Anodal delivery with same current density also increased the total amount of drug transported about 13 folds. It seemed that the increase in flux was due to the electrorepulsion and the increase in passive permeability of the skin by the current application. Flux increased as current density, the duration of current application and loading amount (swelling duration) increased. As the cross linking density of the hydrogel increased, flux clearly decreased. The effect of hydrophilic enhancers (urea, N-methyl pyrrolidone, Tween 20) and some hydrophobic enhancers (propylene glycol monolaurate and isopropyl myristate) was minimal. However, about 3 folds increase in flux was observed when 5% oleic acid was used. Overall, these results provide some useful information on the design of an optimized iontophoretic delivery system of ketoprofen.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.436-449
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• 2017

In this paper, the damage and failure behavior of triaxially braided textile composites was studied using progressive failure analysis. The analysis was performed at both micro and meso-scales through iterative cycles. Stress based failure criteria were used to define the failure states at both micro- and meso-scale models. The stress-strain curve under uniaxial tensile loading was drawn based on the load-displacement curve from the progressive failure analysis and compared to those by test and computational results from reference for verification. Then, the detailed failure initiation and propagation was studied using the verified model for both tensile and compression loading cases. The failure modes of each part of the model were assessed at different stages of failure. Effect of ply stacking and number of unit cells considered were then investigated using the resulting stress-strain curves and damage patterns. Finally, the effect of matrix plasticity was examined for the compressive failure behavior of the same model using elastic, elastic - perfectly plastic and multi-linear elastic-plastic matrix properties.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.2
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• pp.133-140
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• 2017

This paper is a study of the central structural unit model of the sandwich core structure. The applied model is based on the honeycomb structure formed by the truss, the H-shaped honeycomb structure formed by adding the truss of H shape to the space of the center portion, and the honeycomb structure formed by the plate. Applied material property is AISI 304 stainless steel, which has cost effectiveness and easy to get near place. The truss diameter of the model is three different type: 1mm, 2mm and 3mm. ABAQUS software is obtained to do the analysis and applied test is quasi-static loading. Boundary conditions for the analysis are that vertical direction loading at top place without any rotation and bottom surface is fixed. The test results show that the H-truss model has the highest stiffness and yield strength. Therefore, it is hoped that more and more researching for the development of a unit model in sandwich core structure has been investigating and that the developed sandwich core model can be applied into various industrial fields such as mechanical or aerospace industries.

• Journal of Hydrogen and New Energy
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• v.32 no.5
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• pp.293-298
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• 2021

To synthesize Fe/Ni nanocatalysts loaded on carbon black, Iron(II) acetylacetonate and nickel (II) acetylacetonate and were reduced to Fe and Ni metallic nanoparticles by a spontaneous reduction reaction. The distribution of the Fe and Ni nanoparticles was observed by transmission electron microscopy, and the loading weight of Fe/Ni nanocatalysts on the carbon black was measured by thermogravimetric analyzer. The elemental ratio of Fe and Ni was estimated by energy dispersive x-ray analyzer. It was found that the loading weight of Fe/Ni nanoparticles was 6.23 wt%, and the elemental ratio of Fe and Ni was 0.53:0.40. Specific surface area was measured by BET analysis instrument and I-V characteristics were estimated.

• Journal of the Korean Wood Science and Technology
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• v.47 no.3
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• pp.324-335
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• 2019

Timber from plantation forests has inferior physical and mechanical properties compared to timber from natural forest because it is mostly from fast-growing tree species that are cut at a young age. Filling cell voids with methyl methacrylate (MMA) can improve the wood properties. The purpose of this study was to determine the physical and mechanical properties of MMA-impregnated wood from three fast-growing wood species, namely jabon (Anthocephalus cadamba (Roxb.) Miq.), mangium (Acacia mangium Willd) and pine (Pinus merkusii Jungh. & de Vriese). Wood samples were either immersed in MMA monomer or impregnated with it and then heated to induce the polymerization process. Jabon, which was the lowest density wood, had the highest polymer loading, followed by pine and mangium. The physical and mechanical properties of samples were affected by wood species and the presence of MMA, with higher-density wood having better properties than wood with a lower density. Physical and mechanical properties of MMA wood were enhanced compared to untreated wood. Furthermore, the impregnation process was better than immersion process resulting the physical and mechanical properties. Based on MOR values, the MMA woods were one strength class higher compared to untreated wood with regard to Strength Classification of Indonesian Wood.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.715-722
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• 2022

Pt-Fe/carbon black nanocatalysts were prepared by spontaneous reduction reaction of Platinum(II) acetylacetonate and Iron(II) acetylacetonate in a nucleophilic solvent and they were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analyzer (EDS), thermogravimetric analyzer (TGA), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) surface area analysis and anion exchange membrane (AEM) water electrolysis test station. The distribution of the Pt and Fe nanoparticles on carbon black was observed by TEM, and the loading weight of Pt-Fe nanocatalysts on the carbon black was measured by TGA. Elemental ratio of Fe:Pt was estimated by EDS and it was found that elemental ratio of Pt and Fe was changed in the range of 1:0 to 0:1, and the loading weight of Pt-Fe nanoparticles on the carbon black was 5.95-6.78 wt%. Specific surface area was greatly reduced because Pt-Fe nanocatalysts blocked the pores. I-V characteristics were estimated.