• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.372.1-372.1
• /
• 2016

Recently, there are a lot of diseases all around the world. Out of them, Atherosclerosis (AS) is the most common cause of stroke, cardiovascular mortality, and myocardial infarction. The macrophage-derived foam cell, which is formed by oxidized low-density lipoprotein (oxLDL), is the crucial marker for AS. In this study, we report a label-free capacitance imaging technique with multi-electrode array (MEA). The lipid-rich aorta arch lesions, which are derived from an apolipoprotein-E receptor-deficient (apoE-/-) mouse, exhibit higher capacitance than the lipid-free aorta arch, allowing the capacitance imaging of lipid region in atherosclerosis. To improve the contacts between MEA and tissue, polypyrrole(PPy)-coated multi walled carbon nanotubes (MWNTs) multi electrode array (PPy-MWNTs-MEA) was fabricated. Compared to TiN-MEA, PPy-MWNTs-MEA yielded lower contact impedance and better capacitance images. In addition, we have also developed a flexible MEA using single walled carbon nanotubes on a PET substrate. The lipid region could be discriminated in the capacitance images of the lipid-rich aorta arch lesions measured using flexible MEA, demonstrating a feasibility of in vivo applications.

• Transactions of the Korean hydrogen and new energy society
• /
• v.31 no.3
• /
• pp.276-283
• /
• 2020

Alcohol-based solvents including ethanol (EtOH) and tert-butyl alcohol (TBA) are investigated instead of isopropanol (IPA), which is a common solvent for polytetrafluoroethylene (PTFE), as an alternative solvent for preparing the catalyst slurry with PTFE binder. As a result, the performance at 0.2 A/㎠ from the single cells from using catalyst slurries based on EtOH and TBA showed very similar value to that from the slurry using IPA, which implies the EtOH and TBA can be used as a solvent for the catalyst slurry. It is also confirmed by the very close values of the total resistance of the membrane electrode assemblies from the slurries using different solvents. In the energy dispersive spectrometry (EDS) image, the shape of crack and dispersion of PTFE are changed according to the vapor pressure of the solvent.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.9
• /
• pp.57-63
• /
• 2007

The occurrence of a corona is that electrical discharge due to the heterogeneity that occurs when an electrical field is concentrated in an electrode due to a cusp formed on said electrode. Wire treatment at the end of a 154[kV] dead end clamp for end users accelerates the occurrence of corona, which in turn leads to power loss and noise. In this study, the characteristics of the corona which occurs between porcelain insulators and support clamps of overhead lines used in 154[kV] power receiving facilities for end users were investigated. The corona, which cannot be identified by one common method, was measured utilizing a UV image camera. A risk assessment for fire damage and its status was suggested. The stress distribution of the electrical field by length of bare wire was suggested by means of the finite element method(FEMLAB). As a result, it was found to affect a porcelain insulators. These results can be utilized for the enhancement of clamp installation and safety in power facilities.

• The Journal of the Acoustical Society of Korea
• /
• v.18 no.4
• /
• pp.53-59
• /
• 1999

Of various SPUDT SAW filter types, we select the two most common types, DART and EWC/SPUDT, and analyze their performance with the Smith equivalent circuit method. Based on the results for an exemplary case, a usual apodized SAW filter, we investigate the advantage of one type over the other, if any, in a quantitative manner. To compensate for the performance degradation that can happen in the process of the modification of the apodized filer to the SPUDT structure, we apply the triangular weighting technique to wide fingers of the IDT. Further, the variation in performance of the SPUDT structure is investigated in relation to its electrode thickness and the number of fingers. The results in this paper are expected to enable us to easily select an SPUDT type appropriate for each particular application field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.308-309
• /
• 2008

We have proposed a high performance liquid crystal display using two thin film transistors (TFTs) for the large size TFT-LCD desirably 42inch WXGA panel for TVs. The device generates stronger electric fields to reorient liquid crystals than that in the conventional IPS device because the voltages with opposite polarity with respect to the common electrode are applied to each finger-type electrode. As a result, the operation voltage of 2Tr-IPS mode can be decreased and the transmittance can be increased compared to conventional IPS device. Consequently, the 2Tr-IPS has all the advantages over conventional IPS from large size point of view.

• Journal of International Academy of Physical Therapy Research
• /
• v.5 no.2
• /
• pp.718-722
• /
• 2014

The cerebellum is known to control balance, equilibrium, and muscle tone. If the cerebellum becomes damaged, the body is unable to retain its balancing functions or involuntary muscle movement. This is why, in stroke patients, there is a high risk of functional disability, as well as a myriad of other disabilities secondary to stroke. Ischemia was induced in SD mice by occluding the common carotid artery for 5 minutes, after which blood was reperfused. Needle electrode electrical stimulation(NEES) was applied to acupuncture points, at 12, 24, and 48 hours post-ischemia on the joksamri. Protein expression was investigated through caspase-3 antibody immuno-reactive cells in the cerebral nerve cells and Western blotting. The results were as follows: The number of caspase-3 reactive cells in the corpus cerebellum 12 and 24 hours post-ischemia was significantly (p<.05) smaller in the NEES group compared to the GI group. caspase-3 expression 12 and 24 hours post-ischemia was significantly(p<.05) smaller in the NEES group compared to the GI group. Based on these results, NEES seems to have a significant effect on Caspase-3 in the cerebellum in an ischemic state at 12 and 24 hours post ischemia, NEES delays the occurrence of early stage apoptosis-inducing Caspase-3, delaying and inhibiting apoptosis. Further systematic studies will have to be conducted in relation to the application of this study's results on stroke patients.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.390-390
• /
• 2000

This research is the development of a skin-type tactile sensor for service robot using PVDF film for the detection of the contact state. The Prototype of the tactile sensor which has 8$\times$8 taxels was fabricated using PVDF film In the fabrication procedure of the sensor, the electrode patterns and common electrode of the thin conductive tape were attached to the both side of the 28 micro meter thickness PVDF film using conductive adhesive. The sensor was covered with polyester film for insulation and attached to the rubber base for making stable structure. The signals of a contact pressure to the tactile sensor were sensed and processed in the DSP system in which the signals were digitized and filtered. Finally, the signals were integrated for taking the force profile. The processed signals of the output of the sensor were visualized in PC, the shape and force distribution of the contact object were obtained. The reasonable performance for the detection of contact state was verified through the experiment.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.1
• /
• pp.212-218
• /
• 2002

This research is the development of a distributed tactile sensor using PVDF film far the detection of the contact state. The prototype of the tactile sensor with 8$\times$8 taxels was fabricated using PVDF film and flexible circuitry. In the fabrication procedure, the electrode and the common electrode patterns are attached to the both side of the 28${\mu}m$ thickness PVDF film. The sensor is covered with polyester film for insulation. The signals of a contact pressure to the tactile sensor are sensed and processed in the DSP system in which the signals are digitalized and filtered. And the signals are integrated for taking the force profile. The processed signals of the output of the sensor are visualized to take the shape and force distribution of the contact object in personal computer. The usefulness of the sensor system is verified through the sensing examples.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.11
• /
• pp.1007-1013
• /
• 2005

In this study, a step-down piezoelectric transformer was fabricated to utilize as an adapter for charging batteries of mobile electronic appliances. The ceramic part of the transformer is $Pb[(Mn_{1/3}Sb_{2/3})_{_0.05}Zr_{0.475}Ti_{0.475}]O_3$ with mechanical quality factor of 1600, electromechanical coupling coefficient $59\%$, and piezoelectric constant $d_{33}$ 1300, which can be utilized as a piezoelectric transformer. A simply fabricated disk-typed test pattern of diameter 28 mm and thickness 2 mm was used to characterize output voltage, step-down ratio as a function of electrode area with the input remained constant, and power, efficiency as a function of input voltage, and temperature-dependent electric characteristics were evaluated. The sample APT1 showed the best properties. The highest admittance, effective electromechanical coupling coefficient and an appropriate mechanical quality factor were obtained at the sample with the input/output area ratio of 1:1.5 at the common electrode, and the condition of 20 $V_{rms}$, $50\;\Omega$ made the maximum efficiency of $95\%$. The temperature was increased by 14.7'E as the input voltage was increased for $50\;V_{rms},\;50\;\Omega$.

• Journal of International Academy of Physical Therapy Research
• /
• v.3 no.2
• /
• pp.429-434
• /
• 2012

Ischemia, the leading cause of strokes, is known to be deeply related to synaptic plasticity and apoptosis in tissue damage due to ischemic conditions or trauma. The purpose of this study was to research the effects of NEES(needle electrode electrical stimulation) in brain cells of ischemia-induced rat, more specifically the effects of Poly[ADP-ribose] polymerase(PARP) on the corpus striatum. Ischemia was induced in SD mice by occluding the common carotid artery for 5 minutes, after which blood was re-perfused. NEES was applied to acupuncture points, at 12, 24, and 48 hours post-ischemia on the joksamri, and at 24 hours post-ischemia on the hapgok. Protein expression was investigated through PARP antibody immuno-reactive cells in the cerebral nerve cells and western blotting. The number of PARP reactive cells in the corpus striatum 24 hours post-ischemia was significantly(p<.05) smaller in the NEES group compared to the global ischemia(GI) group. PARP expression 24 hours post-ischemia was very significantly smaller in the NEES group compared to the GI group. Results show that ischemia increases PARP expression and stimulates necrosis, making it a leading cause of death of nerve cells. NEES can decrease protein expression related to cell death, protecting neurons and preventing neuronal apoptosis.