• Textile Coloration and Finishing
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• v.24 no.1
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• pp.69-78
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• 2012

This paper surveys the physical properties of the MWNT dispersion solution dispersed with the three types of solvents and of the polyurethane composite film for improvement of mechanical properties and electrical characteristics of PU/MWNT composite film. For this purpose, the MWNT dispersed solution was mixed with three types of solvent such as IPA, MEK and Toluene and then mixed with polyurethane (100part) with variation of loading content (0, 10, 20, 30, 40, 50 part) of MWNT dispersed solution in the ultrasonic wave dispersion apparatus. And eighteen PU/MWNT composite films were prepared as specimens. The various physical properties of these PU/MWNT films were measured and discussed with the loading content of three types of MWNT dispersed solutions. The highest absorbancy among the three types of dispersed solutions was shown in the IPA/MWNT solution. But the absorbancy of PU/MWNT films was not same as the solution. The low electrical surface and volume resistivity of PU/MWNT film were shown at the condition of 20 and 10 parts loading of IPA/MWNT dispersed solution, respectively. The low triboelectricity of PU/MWNT film was shown at the condition of above 30part loading of IPA/MWNT dispersed solution. The breaking strength and strain of PU/MWNT film prepared with IPA/MWNT dispersed solution were decreased with increasing loading content of IPA/MWNT from 10 to 40 parts. The maximum breaking strength and breaking strain according to the dispersion solution were shown on the IPA/MWNT dispersed solution. The uniform dispersion of PU/MWNT film according to the loading content of MWNT solution was shown by surface image analysis on the films dispersed with IPA.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.1
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• pp.5-10
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• 2011

The effect of sample handling condition on the rheological measurement of regenerated silk fibroin formic acid solution using parallel plate geometry was investigated. In case of loading method, the loading by pouring sample solution resulted in the best reproducibility of rheological measurement. Loading with spoon showed a high variance of viscosity value at low shear rate region ($0.01{\sim}1sec^{-1}$) while loading with syringe exhibited a low reproducibility of viscosity at high shear region ($1{\sim}100sec^{-1}$) with a disappearance of shear thinning phenomenon. It was revealed that the sample loading with small extra amount lead to the most reproducible result. The sample loading with the exact amount for the measuring plate resulted in a lack of reproducibility of high shear viscosity, while the loading with large extra volume produced a limited consistency of low shear viscosity. It was turned out that 3 min. of waiting time before measurement was the optimum condition for reliable result. When the waiting time was less than 1 min., the low shear viscosity was obtained with a lack of consistency. On the other hand, the sample solution started drying when the waiting time increased up to 5 min.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.79-84
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• 2012

An efficient protocol for cryopreservation of madder hairy root cultures has been developed using droplet-vitrification. In previous study, combining loading solution C4 (35% PVS3) and vitrification solution B5 (80% PVS3) was the most effective method. In this study, we tried three types of vitrification solution, B5, A3 (90% PVS2, on ice), and A5 (70% PVS2, on ice). Combining loading solution C4 and vitrification solution A5 (on ice) showed the best regeneration rate in this study. Histological changes of the cells within the hairy root of madder were also observed in different steps. The cells from the hairy roots of the control treatment were full and intact with different size of vacuoles and obvious cell nucleus having a dark nucleolus. After the stage of preparing for cryopreservation (after preculturing, loading, followed by dehydration solution A5 or B5), intercellular spaces had become distinct, and within cells, the cytoplasms had become denser and week plasmolyses had appeared. The cell plasmolyses were much more apparent and we measured the degree of plasmolysis by calculating, the area of cell/the area of cytoplasm. The value of plasmolysis degree was the highest in the combination of preculture, loading solution C4, and dehydration solution A5, 1.97. Because the highest regeneration rates appeared in the treatment of A5 for 20 min, we could assume that the optimal degree of plasmolysis for cryopreservation might be around 1.97. The changes in cell structure during cryopreservation might be a useful basis for the development of a proper long-term preservation method for madder germplasms.

• Structural Engineering and Mechanics
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• v.87 no.2
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• pp.165-172
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• 2023

This paper presents a novel method for modeling elastic wave propagation in long beams. The proposed method derives a solution for the transient transverse displacement of the beam's neutral axis without assuming the separation of variables (SV). By mapping the governing equation from the space domain to the frequency domain using Fourier transformation (FT), the transverse displacement function is determined as a convolution integral of external loading functions and a combination of trigonometric and Fresnel functions. This method determines the beam's response to general loading conditions as a linear combination of the analytical response of a beam subjected to an abrupt localized loading. The proposed solution method is verified through finite element analysis (FEA) and wave propagation patterns are derived for tone burst loading with specific frequency contents. The results demonstrate that the proposed solution method accurately models wave dispersion, reduces computational cost, and yields accurate results even for high-frequency loading.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.288-295
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• 2022

This study shows a system identification method of a balancing loading device for a stair climbing delivery robot. The balancing loading device is designed as a 2-axes gimbal structure and is interpreted as two independent pendulum structures for simplifying. The loading device's properties such as mass, moment of inertia, and position of the center of gravity are changeable for luggage. The system identification process of the loading device is required, and the controller should be optimized for the system in real-time. In this study, the system identification method is based on least squares method to estimate the unknown parameters of the loading device's dynamic equation. It estimates the unknown parameters by calculating them that minimize the error function between the real system's motion and the estimated system's motion. This study improves the accuracy of parameter estimation using a null space solution. The null space solution can produce the correct parameters by adjusting the parameter's relative sizes. The proposed system identification method is verified by the simulation to determine how close the estimated unknown parameters are to the real parameters.

• Journal of Information Processing Systems
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• v.10 no.2
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• pp.163-175
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• 2014

This paper will focus on improving the performance of orthogonal frequency division multiplexing (OFDM) in Rayleigh fading environments. The proposed technique will use a previously published method that has been shown to improve OFDM performance in independent fading, based on ordered sub-carrier selection. Then, a simple non-iterative method for finding the optimal bit-loading allocation was proposed. It was also based on ordered sub-carrier selection. We compared both of these algorithms to an optimal bit-loading solution to determine their effectiveness in a correlated fading environment. The correlated fading was simulated using the JTC channel models. Our intent was not to create an optimal solution, but to create a low complexity solution that can be used in a wireless environment in which the channel conditions change rapidly and that require a simple algorithm for fast bit loading.

• Tunnel and Underground Space
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• v.26 no.3
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• pp.154-165
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• 2016

This paper presents experimental results to investigate the affects of acidic solution under loading condition on rock properties. In the experiment, the variations of various rock properties including effective porosity, thermal conductivity, and etc were investigated with different pHs of solution and magnitudes of loading. The results show that the rock property change was increased with low pH under loading. It was predicted that chemical reaction rate would be increased in low pH. Below the crack initiation stress of the rock specimen, the variation of rock property change was reduced with increased loading. It could be explained with the reduced chemical reaction area by the compressional loading if there is no crack generation.

• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.227-233
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• 2011

This study aimed at developing cryopreservation protocol for chrysanthemum (Dendranthema grandiflora Tzelevcv. peak) shoot apices based on droplet-vitrification procedure, which is a combination of droplet-freezing and solution based vitrification. Progressive preculture of shoot apices in liquid MS medium supplemented with 0.3 and 0.7 M sucrose for 31 and 17 hours, respectively, was found optimum among preculture treatments tested. The composition of both loading and vitrification solutions significantly affected recovery growth of shoot tips before and after cryopreservation. Balancing glycerol and sucrose concentrations in the solutions was beneficial for recovery growth. The highest recovery after cryopreservation was observed when apical shoot tips were extracted from 4-week-old in vitro plantlets, progressively precultured with 0.3-0.5-0.7 M sucrose for 32-16-6 hours, respectively, then treated with loading solution comprising of 1.9 M glycerol + 0.5 M sucrose (35% PVS3 solution). Apices were then dehydrated with the vitrification solution consisted of 50% glycerol + 50% sucrose for 90 minutes then directly immersed in liquid nitrogen.

• ETRI Journal
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• v.29 no.1
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• pp.50-58
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• 2007

Robust adaptive beamforming based on worst-case performance optimization is investigated in this paper. It improves robustness against steering vector mismatches by the approach of diagonal loading. A closed-form solution to optimal loading is derived after some approximations. Besides reducing the computational complexity, it shows how different factors affect the optimal loading. Based on this solution, a performance analysis of the beamformer is carried out. As a consequence, approximated closed-form expressions of the source-of-interest power estimation and the output signalto-interference-plus-noise ratio are presented in order to predict its performance. Numerical examples show that the proposed closed-form expressions are very close to their actual values.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.125-128
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• 1996

In this paper, we consider a ring loading problem, which arises in the design of SONET bidirectional rings. We deal with the case where demands are allowed to be split and routed in two different directions. Even if integral . demands are given, the optimal solution of the problem doesn't always have integral values. We present an efficient algorithm which produces an integral optimal solution.