• Fashion & Textile Research Journal
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• v.16 no.5
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• pp.791-799
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• 2014

For development of dyeability, the rayon fabrics were dyed repeatedly with persimmon juice by padding mangle. The merit of padding-based dyeing was easier color reproduction over traditional hand dyeing where various colors and color fastness to light and laundering are hard to obtain. We evaluated the mechanical properties and hand value by Kawabata Evaluation system for dyed rayon fabrics. The results obtained from this study were as follows. With the increase of repeating padding times of dyeing, the linearity load-extension curve and tensile energy per unit length of the rayon fabrics were increased, but the tensile resilience of fabrics were decreased. The value of shear stiffness and shear hysteresis were increased. Also compression resilience and linearity of compression thickness were increased. The rayon fabrics dyed with persimmon juice had shown the thickness and weight increase as the number of padding increase. As repeating times of dyeing with persimmon juice were increased, among the 6 hand values, the item of koshi(stiffness) and Hari(anti-drape stiffness), fukurami(fullness and softness) were increased. while Shinayakasa (flexibility with soft feeling) and Shari(crispness) were greately decreased. The amount of coated persimmon juice on the surface of the fabric was gradually increased as the padding times of dyeing.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.5
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• pp.368-374
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• 2016

This paper presents an experimental study on an electrical circuit model of the TiO2-based nano-wired memristor device for neuromophic applications. The electrical circuit equivalent model of the proposed memristor device consists of several electronics components and some passive devices including operational amplifiers, multipliers, resistors and capacitors. In order to verify the proposed design, both of simulation (using PSPICE) as well as hardware implementation were performed for the analysis of the memristor circuit with time waveforms, frequency spectra, I-V curves and power curves. The gained results from the measured data showed a good agreement with the simulation result that confirm the proposed idea.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.239-242
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• 1990

The effect of $CaCo_3$, $SrCo_3$, $SiO_2$ and $H_3BO_3$ in the range of 0.1-1.0 wt% on strontium ferrites consisting of the magnetoplumbite phase $SrO-5.7Fe_2O_3$ were investigated. The hysteresis loop, density, demagnetization curve and the intrinsic coercive force were measured on anisotropic ferrite. The particle diameter and 0.5(wt%) of second additive $CaCo_3$ is particularly important for the properties of anisotropic ferrite. When the particle diameter is decreased from 1.98(${\mu}m$) to 1.07(${\mu}m$), the remance is increased from 2900 to 4010(G) and the coercive force from 2150 to 2850(Oe) at a sintering temperature 1230 ($^{\circ}C$). Remance Br(G), coercleve force(Oe) and maximum energy product of sample A-16 are87(%), 56(%), 67(%) of S-W model theoretical value.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.440-440
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• 2011

We report on the non-volatile memory characteristics of a bistable organic memory (BOM) device with Au nanoparticles (NPs) embedded in a conducting poly N-vinylcarbazole (PVK) colloids hybrid layer deposited on flexible polyethylene terephthalate (PET) substrates. Transmission electron microscopy (TEM) images show the Au nanoparticles distributed isotropically around the surface of a PVK colloid. The average induced charge on Au nanoparticles, estimated using the C-V hysteresis curve, was large, as much as 5 holes/NP at a sweeping voltage of ${\pm}3$ V. The maximum ON/OFF ratio of the current bistability in the BOM devices was as large as $1{\times}105$. The cycling endurance tests of the ON/OFF switching exhibited a high endurance of above $1.5{\times}105$ cycles and a high ON/OFF ratio of ~105 could be achieved consistently even after quite a long retention time of more than $1{\times}106$ s.

• The Korean Journal of Ceramics
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• v.7 no.1
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• pp.30-35
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• 2001

The contribution of the non-$180^{\circ}C$ domains to the electric-field-induced strains (EFI-strains) of PZT ceramics was evaluated by an XRD method and by an interferometric method. The XRD intensity ratio of 200 and 002 diffraction peaks of tetragonal PZT was measured under strong electric fields. The amount of the $90^{\circ}$ domain reorientation was evaluated and the strain due to the domain reorientation was calculated. It was confirmed that the EFI-strain of PZT ceramics was equal to the sum of the strain calculated from the d$_33$ constant determined by the resonance-antiresonance method and the strain due to the $90^{\circ}$ domain reorientation. The amount of the $90^{\circ}$domain reorientation has a linear relation with the c/a ratio in the "soft" PZT ceramics. A Mech-Zehnder interferometer was constructed to measure the EFI-strains vs. electric-field curves of PZT ceramics as a function of frequency. The EFI-strain vs. electric-field curve showed a hysteresis due to the effect of the non-$180^{\circ}$ domain reorientation when the applied voltage was high and its frequency was low. The apparent piezoelectric constant increased from the d$_33$ value determined by the resonance-antiresonance method with decreasing frequency. This deviation was attributed to the non-$180^{\circ}$ domain contribution.tribution.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.554-570
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• 1990

he rolling contact behaviors between a smooth ball and a flat rough surface under dynamic load are intricately affected by many factors, such as the diameter of a ball, normal load and the roughness of a flat surface etc. Accordingly, the experimental study is done to find them on the base of elastic hysteresis loss as theoretical approach is very difficult. The experimental apparatus composed of damped-free vibration system is used. This paper investigates the damping characteristics on the rolling contact area through rolling friction force and logarithmic decrement versus displacement obtained in accordance with the variations of those factors, and presents a new experimental method to find out contact width using the relations of logarithmic decrement and rolling friction force with displacement.

• Composites Research
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• v.17 no.2
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• pp.1-8
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• 2004

The present paper is concerned with the optimum design of taper spring, in which the static spring rate of the fiber-reinforcement composite material spring is fitted to that of the steel leaf spring. The thickness and width of springs were selected as design variables. The object functions of the regression model were obtained through the analysis with a common analytic program. After regression coefficients were calculated to get functions of the regression model, optimal solutions were calculated with DOT. E-glass/epoxy and carbon/epoxy were used as fiber reinforcement materials in the design, which were compared and analyzed with the steel leaf spring. The result of the static spring rates show that optimized composite leaf springs agree with steel leaf spring within 1%.

• Journal of the Korean Home Economics Association
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• v.26 no.2
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• pp.29-38
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• 1988

The shearing properties, which belong to the mechanical properties of fabrics, are most closely related to the appearnace of weared clothes, formation and feeling of wearing. And they are the elements which show the sense of touch, the properties of drape, folds and recoveryk curve foring, and keeping up formation. Sorts of 156 commercial skil fabrics and polyester fabrics of Korean make for women's cloth were tested for shearing propreties. All samples were classified into for summer and for fall and winter wear. Then shearing properties were measured by kawabata's evluation method. In this study shear stiffness(G) and shear hysteresis (2HG, 2HG5) of shearing prperties were measurd, then G/W and 2HG/G which are concerning to formation of weared clothes and trnsformatio behavior wre properties. The results obtained are as follows: 1. Silk fabrics were higher than polyester fabrics in G and 2HG. Thickness and weight of the fabrics for summer were a third to a half of those of the fabrics for fall and winter, but shearing properties were almost the same in the two types of the fabrics. 2. Fabrics for fall and winter were lower than fabrics for summer in G/W and fabrics for summer were lower than fabrics for fall and winter in 2HG/G. 3. korean women's silk cloth was much lighter than Japanese kimono cloth in weight but thickness and shearing properties were almost the same in the two types of the clothes.

• Structural Engineering and Mechanics
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• v.42 no.1
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• pp.73-93
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• 2012

With an active structural involvement in spiral case structure (SCS) that is always the design and research focus of hydroelectric power plant (HPP), the compressible membrane sandwiched between steel spiral case and surrounding reinforced concrete was often assumed to be linear elastic material in conventional design analysis of SCS. Unfortunately considerable previous studies have proved that the foam material serving as membrane exhibits essentially nonlinear mechanical behavior. In order to clarify the effect of membrane (foam) material's nonlinear stress-strain behavior on SCS, this work performed a case study on SCS with a compressible membrane using the ABAQUS code after a sound calibration of the employed constitutive model describing foam material. In view of the successful capture of fitted stress-strain curve of test by the FEM program, we recommend an application and dissemination of the simulation technique employed in this work for membrane material description to structural designers of SCS. Even more important, the case study argues that taking into account the nonlinear stress-strain response of membrane material in loading process is definitely essential. However, we hold it unnecessary to consider the membrane material's hysteresis and additionally, employment of nonlinear elastic model for membrane material description is adequate to the structural design of SCS. Understanding and accepting these concepts will help to analyze and predict the structural performance of SCS more accurately in design effort.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.105-113
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• 2004

MRAM uses magneto-resistance material as a storage element, which stores cell data as a polarization of spin in a free magnetic layer. This magneto-resistance material has hysteresis, asteroid curve at the thermal variation, and R-V characteristics for switching the data. Therefore, a macro-model which can reproduce these characteristics is required for MRAM simulation. We propose a macro-model of TMR (Tunneling Magneto Resistance) that can reproduce all of these characteristics on HSPICE. Also we propose a novel sensing scheme, which generates reference resistance having the medium value, ( $R_{H}$+ $R_{L}$)/2, for a wide range of applied voltage and present simulation results based on the HSPICE macro-model of MTJ that we have developed.d.d.