• Korean Journal of Acupuncture
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• v.37 no.4
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• pp.262-270
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• 2020

Objectives : The aim of this study is to evaluate the effect of Daebangfung-tang (DBFT) on suppressing muscle atrophy followed by immobilization. Methods : Twenty young male Sprague-Dawley rats were randomized into two groups. The rats in experimental group (DBFT group) were orally administrated DBFT once a day for 2 weeks, and the rats in control group were given normal saline in the same manner. The immobilization on left leg was carried out using casting tape. The morphologies of gastrocnemius in both groups were assessed. The cross sectional area of them was measured by image analyzer. Immunohistochemical staining was implemented and the numbers of immunopositive cells implying the expression of TNF-α were measured and quantified. Results : DBFT represented the significant suppressive effects against the weight loss of the left gastrocnemius muscle and the reduction in cross sectional area of the left gastrocnemius muscle compared with normal saline. Also the treatment with DBFT significantly reduced the expression of TNF-α in gastrocnemius compared with normal saline. Conclusions : DBFT is thought to have the significant suppressive effect against muscle atrophy followed by immobilization.

• Composites Research
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• v.20 no.5
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• pp.49-55
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• 2007

Nanocomposite blade for dicing semiconductor wafer is investigated for micro/nano-device and micro/nano-fabrication. While metal blade has been used for dicing of silicon wafer, polymer composite blades are used for machining of quartz wafer in semiconductor and cellular phone industry in these days. Organic-inorganic material selection is important to provide the blade with machinability, electrical conductivity, strength, ductility and wear resistance. Maintaining constant thickness with micro-dimension during shaping is one of the important technologies fer machining micro/nano fabrication. In this study the fabrication of blade by wet processing of mixing conducting nano ceramic powder, abrasive powder phenol resin and polyimide has been investigated using an experimental approach in which the thickness differential as the primary design criterion. The effect of drying conduction and post pressure are investigated. As a result wet processing techniques reveal that reliable results are achievable with improved dimension tolerance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.263-269
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• 2017

A piezoelectric cantilever energy harvester (PCEH) driven in longitudinal (3-3) vibration mode was fabricated, and its electrical properties were evaluated by varying the resistive load. A commercial PZT piezoelectric ceramic with a high piezoelectric charge constant ($d_{33}$) of 520 pC/N and the interdigitated (IDT) electrode pattern was used to fabricate the PCEH driven in longitudinal vibration. The IDT Ag electrode embedded piezoelectric laminates were co-fired at $850^{\circ}C$ for 2 h. The 3-3 mode PCEH was successfully fabricated by attaching the piezoelectric laminates to a SUS304 elastic substrate. The PCEH exhibited a high output power of 3.8 mW across the resistive load of $100k{\Omega}$ at 100 Hz and 1.5 G. This corresponds to a power density of $10.3mW/cm^3$ and a normalized global power factor of $4.56mW/g^2{\cdot}cm^3$. Given the other PCEH driven in transverse (3-1) vibration mode, the 3-3 mode PCEH could be better for vibration energy harvesting applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.768-775
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• 2017

Energy harvesting characteristics of trapezoidal piezoelectric cantilever generator, which has a lead zirconate titanate (PZT) laminate film, were compared by longitudinal (3-3) and transverse (3-1) modes. The PZT laminate film, fabricated by a conventional tape casting process, was cofired with Ag electrode at $850^{\circ}C$ for 2 h. A multi-layered Ag electrode by a planar pattern and an interdigitated pattern was applied to the PZT laminate to implement the 3-3 and 3-1 modes, respectively. The energy harvesting performance of the 3-3 mode trapezoidal piezoelectric cantilever generator was better than that of the 3-1 mode. An extremely high output power density of $26.7mW/cm^3$ for the 3-3 mode was obtained at a resonant frequency of 145 Hz under a load resistance of $50{\Omega}$ and acceleration of 1.3 G, which is ~3-times higher than that for the 3-1 mode. Therefore, the 3-3 mode is considered significantly efficient for application to high-performance piezoelectric cantilever generator.

• Korean Journal of Materials Research
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• v.11 no.6
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• pp.519-526
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• 2001

The effects of methyl isobutyl ketone(MIBK)/ethanol(EtOH) solvent mixtures on the dispension, particle size distribution and rheology of $Al_2$O$_3$/ZrO$_2$ nonaqueous suspensions were investigated by measuring sedimentation density and viscosity. The sedimentation density of $Al_2$O$_3$ and ZrO$_2$ particles increased in MIBK-rich($\geq$60 vol%) solvents with 'Hypermer' KD-1 as a dispersant. The ball-milled suspensions in 80MIBK/20EtOH(vol%) solvent exhibited the narrow and unimodal particle size distribution. Although all Suspensions exhibited the Pseduo-Plastic flow(Shear thinning) the shear thinning behavior was somewhat different depending on the mixture ratio of $Al_2$O$_3$/ZrO$_2$ and MIBK/EtOH. Under a given shear rate( <300 s$^{-1}$ for $Al_2$O$_3$; <3000 s$^{-1}$ for ZrO$_2$) the strongest shear thinning appeared in the $Al_2$O$_3$ and ZrO$_2$ suspensions with pure MIBK solvent. The shear thinning was nearly independable on the mixture ratio of $Al_2$O$_3$/ZrO$_2$ in case of using the identical solvent(80MIBK/20EtOH, vol%).

• Journal of the Korean Electrochemical Society
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• v.9 no.3
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• pp.124-131
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• 2006

For commercialization of molten carbonate fuel cell (MCFC), it has some problems to be overcome such as decrease of porosity and thickness of the anode under the operating condition (at $650^{\circ}C$ and working pressure of more than 2 $kg_f/cm^2$). Recently, Ni-Al alloy anode has been proposed to replace the conventional Ni-Cr anode as an alternative material to resist a creep and inhibit the sintering. The objective of this research is to sinter the green sheet of Ni-Al alloy anode during single cell pre-treatment process, which has several advantages like cost down and simplification of manufacturing process. However, the Ni-Al alloy anode prepared with a conventional pre-treatment process showed the phase separation of Ni-Al alloy and formation of micropore(${\leqq}0.4{\mu}m$), resulting in low creep resistance and high electrolyte re-distribution. In order to prevent the Ni-Al alloy anode from phase-separating, nitrogen gas was used in the process of pre-treatment. Introducing the nitrogen, the phase separation from Ni-Al alloy into nickel and alumina was minimized and increased creep resistance. However, there was some micropore formation on the surface of Ni-Al alloy anode during the cell operation due to creation of lithium aluminate. Addition of more amount of electrolyte into a cell, especially at cathode, made the cell performance stable for 2,000 hrs. Consequently, it was possible to make the Ni-Al alloy anode with good creep resistance by the modified in-situ sintering technique.