• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.362-368
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• 2023

Multilayered actuators using Pb(Mg_1/3Nb_2/3)O₃-Pb(In_1/2Nb_1/2)O₃-PbTiO₃ (PMN-PIN-PT) crystals have demonstrated excellent properties, but are costly and lack mechanical strength. Textured PMN-PIN-PT ceramics exhibit robust mechanical strength and comparable properties to their single crystals form. However, the development of multilayered actuators using textured PMN-PIN-PT ceramics has not been achieved until now. This study presents the development of a multilayered actuator using textured 0.37PMN-0.29PIN-0.34PT ceramics with an Ag_0.9/Pd_0.1 inner electrode, co-fired at 950℃. A random 0.37PMN-0.29PIN-0.34PT ceramics multilayered actuator was also developed for comparison. The multilayered actuator consisted of 9 ceramic layers (36 ㎛ thickness) with an overall actuator thickness of 0.401 mm. The textured and random 0.37PMN-0.29PIN-0.34PT ceramics-based multilayered actuators achieved displacements of 0.61 ㎛ (0.15% strain) and 0.23 ㎛ (0.057% strain) at a low applied peak voltage of 100 V. These results suggest that the developed multilayered actuator using high-performance textured 0.37PMN-0.29PIN-0.34PT ceramics has the potential to replace expensive single crystal-based actuators cost-effectively.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.206-211
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• 2003

Effects of substrates and buffer layer upon the formation of crystalline phases and ferroelectricity of $YMnO_3$ thin films were investigated. The hexagonal $YMnO_3$ was easily formed on Si(100) while the mixed phases, hexagonal and orthorhombic $YMnO_3$, on $Pt(111)/TiO_2/SiO_2/Si$ substrate. When the $Y_2O_3$ buffer layer of 70 nm thick was inserted between the substrates and the $YMnO_3,$ the c-axis oriented hexagonal single phase formed on both substrates, Si(100) and $Pt(111)/TiO_2/SiO_2/Si$. The leakage current density of the hexagonal $YMnO_3$ thin films was lower than that consisting of mixed phases, hexagonal and orthorhombic. Furthermore the hexagonal $YMnO_3$ with c-axis preferred orientation showed the lowest leakage current density. The remnant polarization from a P-E hysteresis curve for the $YMnO_3$ formed on Si(100) was 0.14 without buffer layer and $0.24_{mu}C/cm^2$ for that with buffer layer. For the $Pt(111)/TiO_3/SiO_3/Si$ substrates, the specimen without $Y_2O_3$buffer layer did not show the hysteresis curve, while the buffer-layered has the remnant polarization of $1.14_{mu}C/cm^2$. It was concluded that the leakage current density and the ferroelectricity for the $YMnO_3$ thin films could be controlled by varying crystalline phases and their preferred orientation which depend on the kind of substrates and whether the $Y_2O_3$buffer layer exist or not.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.115-128
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• 1992

The training of male wistar rats for active conditioned response (ACR) was performed by one daily training session of 30 consecutive trials for 10 successive days using a two-way shuttle box, and the rats that showed 10 or more ACRs on the last day were treated for further 10 days with electroconvulsive shock (ECS : 50 mA, 0.5 msec; 100 Hz; 1.5 sec) and the following compounds. On the 20th day, all the rats were tested for the ACR rention. The ECS regimens were one ECS per day for 10 days with one day interval $(5{\times}ECS)$, one ECS at 3 hrs (ECS-3h), and one ECS at 24 hrs (ECS-24h), respectively, before the ACR retention test. And CDP-choline (cc: 250 mg/kg), spermine (SM: 10 mg/kg), ${\alpha}-difluoromethylornithine$ (DO: 250 mg/kg), or aminoguanidine (AG: 100 mg/kg) was administered by one daily i.p. injection for 10 days. The ACR number $(13.7{\pm}1.0)$ obtained on the last training day was increased by 37.23% on the 20th day in the control rats. And the ACR increase was significantly suppressed by 5-ECS, ECS-3h, CC, or SM but was little affected by ECS-24h, DO, or AG. However, the 5-ECS induced impairment of ACR retention was significantly suppressed by AG, SM, and CC in the order of potency but was little affected by DFMO. And the ECS-3h induced impairment was moderately worsened by SM or AG. The acetylcholine (ACh) of the rat hypothalamus (HT), hippocampus (HC), and entorhinal cortex (EC) was markedly increased by CC and moderately increased by SM, but little affected by ECS-3h, ECS-24h, DO, or AG. But $5{\times}ECS$ slightly increased the ACh content. The brain putrescine (Pt) content was significantly increased by AG and little affected by CC, SM, or DO. But the $5{\times}ECS$ markedy decreased the brain Pt content, and the decrease was significantly suppressed by CC, SM, or AG. CC induced the marked increases of the spermidine (Sd) and spermine (Sm) contents of all the areas. SM increased the Sd contents of all the areas and the EC-Sm content. DO decreased the brain Sd and Sm contents. And AG increased the HT-Sd content and the Sm contents of all the brain areas. The $5{\times}ECS$ induced decrease of the HC-Sm content was suppressed by CC, SM and AG. These results suggest that the improving effect of aminoguanidine on the $5{\times}ECS$ induced impairment of ACR retention may be ascribed in part to its activity as a diamine oxidase inhibitor.

• Journal of Korean Physical Therapy Science
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• v.15 no.4
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• pp.43-50
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• 2008

Background: This study is intended as an investigation of the recognition for physical and occupational therapist on the Pilates. Methods: Thirty three therapist were participated in instruction of C-college, completed questionnaire form and then analyzed data. Results: Subjects who don't instruct or practice on the Pilates was 90.9% and physical therapist(PT) was 83.3%, occupational therapist(OT) 100%. 57.6% subjects was well aware of the Pilates by the media and was a most higher respondents. Therapists knowing the exact effect of the Pilates was 54.5%. PT was 33.3%, OT 80.0% and between PT and OT groups were significant difference(p<.05). Therapists knowing the exact practice with Pilates method of applicable a patient was 54.5%. In relation to Pilates and rehabilitation, a lot was 18.2%, a yes 69.7% and a little 12.1%. Therapists have applied the Pilates in rehabilitation was 12.1%. In minded therapists applying the Pilates after instruction, a lot was 24.2%, a yes 69.7%, a little 6.1% and a none 0%. Conclusion: Judging from the above, the knowledge and recognition of the Pilates for PT and OT was low and the will applying for therapy was high. Therefore, therapist is in need of instruction of the Pilates and further research on the Pilates and therapist would clarify the development of PT or OT.

• Analytical Science and Technology
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• v.29 no.1
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• pp.35-42
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• 2016

A new nano-composite carbon ink for the development of disposable dopamine (DA) biosensors based on screen-printed carbon electrodes (SPCEs) is introduced. The method developed uses SPCEs coupled with a tyrosinase modified nano-composite carbon ink. The ink was prepared by an “in-house” procedure with reduced graphene oxide (rGO), Pt nanoparticles (PtNP), and carbon materials such as carbon black and graphite. The rGO-PtNP carbon composite ink was used to print the working electrodes of the SPCEs and the reference counter electrodes were printed by using a commercial Ag/AgCl ink. After the construction of nano-composite SPCEs, tyrosinase was immobilized onto the working electrodes by using a biocompatible matrix, chitosan. The composite of nano-materials was characterized by X-ray photoelectron spectroscopy (XPS) and the performance characteristics of the sensors were evaluated by using voltammetric and amperometric techniques. The cyclic voltammetry results indicated that the sensors prepared with the rGO-PtNP-carbon composite ink revealed a significant improvement in electro-catalytic activity to DA compared with the results obtained from bare or only PtNP embedded carbon inks. Optimum experimental parameters such as pH and operating potential were evaluated and calibration curves for dopamine were constructed with the results obtained from a series of amperometric detections at −0.1 V vs. Ag/AgCl. The limit of detection was found to be 14 nM in a linear range of 10 nM to 100 µM of DA, and the sensor’s sensitivity was calculated to be 0.4 µAµM⁻¹cm⁻².

• Journal of Sensor Science and Technology
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• v.9 no.2
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• pp.113-119
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• 2000

In this work, Pd/Pt gate MISFET sensor using Pd membrane was fabricated to detect the hydrogen in DI water. A differential pair-type was used to minimize the intrinsic voltage drift of the MISFET. To avoid hydrogen induced drift of the sensor, the silicon dioxide/silicon nitride double layer was used as the gate insulator of the FET's. In order to eliminate the blister formation on the surface of the hydrogen sensing gate metal, Pd/Pt double metal layer was deposited on the gate insulator. For this type of application sensors need to be isolated from the DI water, and a Pd membrane was used to separate the sensor from the DI water. The output voltage change due to the variation of hydrogen concentration is linear from 100ppm to 500 ppm.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.3
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• pp.156-160
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• 2007

We evaluated the newly developed plastic sodium citrate tubes for routine coagulation test by direct comparison with glass citrate theophylline adenosine dipyridamole (CTAD) tubes. Blood was drawn from 100 patients into glass CTAD tubes and plastic sodium citrate tubes. After collection, samples were centrifuged at 1500 ${\times}$g for 15 min at $22^{\circ}C$. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen were measured by using the Coagrex-800 (IRC, Japan). We used comparison plot by linear regression model and difference plot graphs to compare the results of the independent measurements of PT, aPTT, fibrinogen between glass CTAD tubes and plastic sodium citrate tubes. On the comparison study between glass CTAD tubes and plastic sodium citrate tubes, the correlation coefficients (R) were 0.99 for PT, 0.97 for aPTT and 0.97 for fibrinogen. This results implicated good correlation of each parameter between two tubes. Although the difference plot graph analysis showed statistically significant differences between glass and plastic tubes for PT, aPTT and fibrinogen, the range of difference was acceptable according to the CLSI/NCCLS guideline. The plastic sodium citrate tubes showed good correlation with the glass CTAD tubes, so it can substitute glass citrate tube for routine coagulation tests.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.127-131
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• 2005

We report a nanometer scale mark formation using a $PtO_x$ thin film or a TbFeCo rare-earth transition metal film and the mechanism. The multi-layer samples($ZnS-SiO_2/PtOx/ZNS-SiO_2,\;ZnS-SiO_2/TbFeCo/ZnS-SiO_2$) were prepared with a magnetron sputtering method on a polycarbonate or a glass substrate. By laser irradiation of approximately a few nanoseconds, nanometer scale marks were fabricated. During the fabrication process, the thin films were thermally reacted or inter-diffused during the laser irradiation. 75 nm bubble marks in the PtOx multi-layer sample by an approximately 4-ns laser irradiation. Inside the bubble mark, Pt particles with a few nanometer sizes are distributed. The $50{\sim}100$ nm bubble marks in the TbFeCo multi-layer sample by a few nanosecond laser irradiations. We will report the detail structure of the samples, the bubble mark formation process and the mechanism.

• Journal of Magnetics
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• v.21 no.1
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• pp.35-39
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• 2016

$Cr_{100-x}Ti_x$ amorphous texture-inducing layers (TIL) were investigated to realize highly (002) oriented $L1_0$ FePt-C granular films through hetero-epitaxial growth on the (002) textured bcc-$Cr_{80}Mn_{20}$ seed layer (bcc-SL). As-deposited TILs showed the amorphous phase in Ti content of $30{\leq}x(at%){\leq}75$. Particularly, films with $40{\leq}x{\leq}60$ kept the amorphous phase against the heat treatment over $600^{\circ}C$. It was found that preference of the crystallographic texture for bcc-SLs is directly affected by the structural phase of TILs. (002) crystallographic texture was realized in bcc-SLs deposited on the amorphous TILs ($40{\leq}x{\leq}70$), whereas (110) texture was formed in bcc-SLs overlying on crystalline TILs (x < 30 and x > 70). Correlation between the angular distribution of (002) crystal orientation of bcc-SL evaluated by full width at half maximum of (002) diffraction (FWHM) and a grain diameter of bcc-SL indicated that while the development of the lateral growth for bcc-SL grain reduces FWHM, crystallization of amorphous TILs hinders FWHM. $L1_0$ FePt-C granular films were fabricated under the substrate heating process over $600^{\circ}C$ with having different FWHM of bcc-SL. Hysteresis loops showed that squareness ($M_r/M_s$) of the films increased from 0.87 to 0.95 when FWHM of bcc-SL decreased from $13.7^{\circ}$ to $3.8^{\circ}$. It is suggested that the reduction of (002) FWHM affects to the overlying MgO film as well as FePt-C granular film by means of the hetero-epitaxial growth.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.162-162
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• 2000

We have studied magnetic properties of Co/Pt multilayered films which have attracted great interest as high-density magneto-optical (MO) recording media due to their good MO properties. For this study, [Pt(45 )/Co(35 )]$\times$8 films were deposited with a Pt buffer layer of 60 on Si(100) substrate by alternating electron-beam evaporation in a high vacuum and were ion beam mixed by using 80keV Ar+ at 25$0^{\circ}C$. Especially, an external magnetic field was added to help changing magnetic property during ion beam mixing (IBM). The intermixing of Co and Pt layers after IBM was confirmed with Rutherford Backscattering Spectroscopy (RBS) and Transmission Electron Microscopy (TEM). The MO property of the film was measured with magneto-optical Kerr spectrometer and the change of magnetic easy axis in the film plane was observed from Ker loop data. This anomalous result might be correlated with the change of atomic structure due to the intermixing effect.