• Advances in materials Research
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• v.4 no.4
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• pp.207-214
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• 2015

It has been reported in the technical literature that orotic acid can be used in order to induce improved crystallization of biodegradable and biocompatible polymers like poly(L-lactic acid), polyhydroxybutyrate and poly(hydroxybutyrate-co-hydroxyhexaonat). The expected advantage of the changed crystalline structure is a reinforcing effect of the polymers. A lot of papers reported about the application of inorganic and organic agents for acceleration of heterogeneous nucleation. This study reports on an attempt to use orotic acid as appropriate non-toxic nucleating agent for improving mechanical properties of isotactic polypropylene. Special attention is given to demonstrate the effect of nucleation in a typical melt spinning process in order to improve the mechanical properties. The effects were demonstrated using rheology, thermal analysis and tensile testing.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.223-230
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• 1996

Fine structure of the neuromuscular junction in the venomous organ of the spider, Agelena li'mbutq, was studied using high magnification electron microscope. The motor nerve endings at neuromuscular contact area composed of neurons and neuroslial cells were located between musculature and extracellular sheath of the venom gBand. At the synaptic contact between a motor axon and a muscle fiber in the musculature, spherical synaptic vesicles were prominent in the nerve terminal. The sarcoplasm beneath the neuromuscular synapse has a granular appearance and lacks mvofilaments. And the main axon gives off a branch between the muscle fibers. The synaptic regions of this organ are located close to the myofilaments unlike to other chelicerate classes. Moreover the postsvnaptic complex of vesicles and membrane invasinations present in other synaptic legions are absent from these legions in this venomous organ.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.1
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• pp.81-90
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• 2004

Farmers need timely information on the nutritional status of their animals and the nutritive value of pastures and supplementary feeds if they are to apply successfully this existing nutritional information. Near infrared reflectance(NIR) spectroscopy has been used over the last forty years to analyse accurately protein, fiber, and other organic components in animal foods. NIR spectroscopy is a rapid, non-destructive, and non-polluting technology. When properly calibrated, NIR spectroscopy is used successfully with both concentrate and forage feeds. NIR methods predict in vitro digestibility accurately and precisely, and can predict in vivo digestibility at least as well as conventional "wet chemistry" methods such as in vivo digestion or the pepsin-cellulase method, and much more rapidly. NIR technology has been applied to the routine monitoring (through analysis of feces samples) of the nutritional status of cattle and other grazing animals. This report reviews the use of near infrared reflectance(NIR) spectroscopy to monitor the nutritive value of animal feeds and the nutritional status of grazing animals.

• KCI Concrete Journal
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• v.12 no.1
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• pp.35-46
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• 2000

A research program was initiated at the University of Colorado at Boulder to develop computational models that can be used for seismic risk assessments. To assess the overall performance of bridge structures including the nonlinear effects of bridge piers, the research focused on two levels of capabilities, i.e. global and local pier levels. A 3-D concrete model was used to evaluate the behavior of individual piers under combined axial, bending, and shear loadings using 3-D finite element analysis. Whereby the response curve reached the peak strength of the R/C column under the constant axial and monotonically increasing lateral loads. Experimental results on reinforced concrete bridge piers, which were obtained at the University of California at San Diego were used to validate the seismic performance of bridge piers at the two levels, globa1 and local.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.673-676
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• 2006

Steel FibreReinforced Shotcrete(SFRS) is one of the main tunnel support along with the rock bolt during the excavation and after the completion of the tunnel. In the standard qualification of the SFRS defined by Korea Highway Corporation, 28 day core specimen has to meet the compressive strength of 19.6 MPa and over 90 % fibre contents. Furthermore, for the 28 days brick shaped specimen made by shooting, flexural strength should be over 4.4 MPa and flexural toughness ratio which can be calculated from flexural toughness factor has to meet more than 68% of flexural strength. In shotcrete, accelerating agent is added for the rapid strength development. Silicate and aluminate type agents are known to develop shotcrete strength rapidly, however, has such problem to degrade the middle and long term strength. Hence, using poly carboxylic super plasticizer, it was aimed to enhance the quality of the shotcrete with the lower water-cement ratio and the same level of workability. The present paper shows the part of the field test result and its analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.3-4
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• 2011

The purpose of this study is to suggest basic data for development optimal disassembly manufacturing system during analysis pore structure and heating properties of cementitious joint using conductive resister by induction heating. From the results, we knew cementitious joint is weak easily by heating of conductive resister, such as wire mesh, punching metal, and steel fiber, from induction heating.

• Steel and Composite Structures
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• v.17 no.2
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• pp.159-172
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• 2014

A finite element model with the consideration of damage initiation and evolution has been developed for the analysis of the dynamic response of a composite sandwich panel subject to low velocity impact. Typical damage modes including fiber breakage, matrix crushing and cracking, delamination and core crushing are considered in this model. Strain-based Hashin failure criteria with stiffness degradation mechanism are used in predicting the initiation and evolution of intra-laminar damage modes by self-developed VUMAT subroutine. Zero-thickness cohesive elements are adopted along the interface regions between the facesheets and the foam core to simulate the initiation and propagation of delamination. A crushable foam core model with volumetric hardening rule is used to simulate the mechanical behavior of foam core material at the plastic state. The time history curves of contact force and the core collapse area are obtained. They all show a good correlation with the experimental data.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.13-18
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• 2007

In this paper, authors deal with an application of power quality monitoring using the Sampled Value which is described in the IEC61850 International Standard for substation communication. Firstly, while Merging Unit is designed as a process level device transmitting sensor data, the practical problems such as time delay compensation and optical fiber communication are issued. Secondly, the Sampled Value message which is proper to a power quality monitoring system is presented. Because the power quality monitoring system requests non time critical service comparing to protection and control applications, the Sampled Value service message structure is introduced to improve efficiency. At last, the power quality monitoring server having various power quality analysis functions is suggested to verify the performance of Merging Unit. With the diverse experiments, it is proved that the process bus distributed solution is flexible and economic for the power quality monitoring.

• Journal of the Korean Society of Clothing and Textiles
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• v.15 no.4 s.40
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• pp.431-435
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• 1991

The dispersion and Poiar force components of the surface free energy of PET fibers untreated and treated with hydrophilic chemicals, such as nonionic-soil release polymer (SRP), anionic, nonionic and hydrophilic silicone, were determined using harmonic-mean and geometric-mean methods. Contact angles of water and methylene iodide on the fibers were determined from the adhesion tensions using tensiometric method. Fibers treated with hydrophilic chemicals have the increased polar force component and the decreased dispersion force component. The adhesion tensions of triolein for the hydrophilic treated fibers were smaller than that for untreated fiber.

• Textile Coloration and Finishing
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• v.9 no.6
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• pp.87-95
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• 1997

Wool samples were treated by potassium tert-Butoxide(t-BuOK) in anhydrous tert-butanol to remove the bound surface lipid-layer, and the weight loss behaviors in protease solution and dyeabilities of the samples were studies. The C/N ratio of the surface of the t-BuOK-treated wool was shown to be 4.3 from XPS analysis. From SEM pictures any remarkable change in the shape of surface curticle during the proteasw treatment was not observed regardless of prior t-BuOK treatment. Dyeing rate and equilibrium adsorption of Orange II, a typical levelling type acid dye, on wool were not changed by protease or t-BuOK treatment, but those of Milling Cyanine 5R, a typical milling type acid dye, on wool were greatly enhanced by t-BuOK treatment in spite that, from alkali and urea-bisulfite solubilities, no damage on the inner part of wool fiber was expected by t-BuOK treatment.