• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.137-145
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• 2004

Limestone zone in korea have been distributed to diagonal line so that it is wide from the Gangwondo to the Jeonlanamdo. The limestone cavity and fractured zone were formed by chemical weathering. Limestone cavity and fractured zone was reinforced with cemented milk(w/c=60%)by high pressure jet grouting by tripple -pipe to establish bridge foundation on the ground condition like limestone cavity. To analyze property of limestone and solid of cement milk(w/c=65%), mixed solid of cement, core NX size in the limestone cavity and fractured zone and compressive strength. Seismic tomograpy exploration was pcrforn1cd to analyze deformation modulus of limestone. The analysis suggests that deformation modulus of limestone has effect on uniaxial compressive strength, seismic velocity, seismic elasticity modulus. Average static elasticity modulus of limestone is $5.08{\times}10^5kgf/cm^2$, cement and coal mixed solid is $0.25{\times}10^5kgf/cm^2$, $0.095{\times}10^5kgf/cm^2$. Average seismic velocity of limestone is 5.240m/sec, cement and coal mixed solid is 2,211.3m/sec, 1,447.5m/sec. Average uniaxial compressive strength of limestone was $1,221.3kgf/cm^2$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $125.22kgf/cm^2$, $35kgf/cm^2$ each other. Average friction angle of limestone was $49.14^{\circ}$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $38.39^{\circ}, 25.83^{\circ}$ each other. Average cohesion of limestone was $137.7kgf/cm^2$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $23.5kgf/cm^2$, $15.5kgf/cm^2$ each other. Average deformation modulus of limestone was $2.84{\times}10^5kgf/cm^2$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $0.4{\times}10^5kgf/cm^2, 0.12{\times}10^5kgf/cm^2$ each other. It was analyzed that the elasticity and uniaxial compressive strength, seismic velocity of solid of cement milk mixed limestone pieces and coal had an highly interrelation regardless of existence of limestones pieces and coal but it had shown that limestones had an lower interrelation. In case of field seismic velocity and deformation of limestone, SIC solid of cement milk mixed with coal and limestone pieces had an highly interrelation.

• Polymer(Korea)
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• v.36 no.4
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• pp.440-447
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• 2012

The branched copolyester was synthesized and its molecular weight, $T_g$, 1/2 method temperature ($T_{1/2}$) and rheological properties were characterized for the application of toner binder. The linear copolyester had low molecular weight and melt elasticity obtained by dimethylterephthalate (DMT), ethylene glycol (EG) and 2,2-bis(4-(2-hydroxypropoxy) phenyl)propane (HPP). The branched copolyesters prepared with various branching agents such as 2-(hydroxymethyl)-2-ethylpropane-1,3-diol (trimethylol propane, TMP), 2,2-bi(hydroxymethyl)-1,3-propanediol (pentaerythritol, PER), 1,2,4-benzenetricarboxylic anhydride (trimellitic anhydride, TMA) and glycerol to improve the physical properties of the linear copolyester. The effect of branching agents on the molecular weight and melt elasticity of the branched copolyester was examined. The branched copolyesters prepared by adding over 15 mol% of branching agent showed relatively high molecular weight and melt elasticity, and $T_{1/2}$ value of $140^{\circ}C$. Therefore, the highly branched copolyesters were deemed suitable as a hot-melt toner of laser print process.

• Korean journal of food and cookery science
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• v.13 no.1
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• pp.7-15
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• 1997

The composition and polymeric structure of starch are the most important factors to determine the functional properties of rice. In an effort to relate the structural characteristics and its functional properties of starch in rice, molecular structural properties of starch from 6 rice cultivars were analysed. To relate the structure and function of starch the texture of Jeung-pyun made of rice were analyzed during retrogradation. The polymeric structure of rice starch was analyzed by debranching with isoamylase after gelatinization and fractionated with Sephadex G-75 gel filteration. The size fractionated debranched starch was categorized into four groups such as Fraction I, II, III and Intermediate Fraction depending in their max, The fractions with the max higher than 620 nm were designated as Fraction I, while those in the range of 600-620 nm and 540-600 nm as the Intermediate Fraction and Fraction II, respectively. The Fractions with the max lower than 540 were described as Fraction III. The average degree of polymerization (DP) of the Fraction I was estimated to be higher than 200, and those of other fractions, i.e. the Intermediate Fraction I, Fraction II and III were 150,45 and 25, respectively. The levels of Fraction I were varied from II to 35％ of total sugar. The Fraction I showed the linear relationship with the amylse contents, and the Intermediate Fraction, which might contain the mixture of short chain of amylose and debranched long chain of amylopectin, were measured to be in the range of 2.7∼8.4%. The levels of fraction II and III, both to be considered as the branches of amylopectin, were ranged 14.5∼23.6% and 39.7∼73.0%, respectively. The ratio of Fraction III to Fraction II describing the degree of branch or compactness of amylopectin was estimated to be around 4.0 for waxy varieties and around 2.0 for high amylose cultivars. With these results, it can be suggested that the degree of branch of the amylopectin may effect on amylose contents of starch or rice versa, To invertigate processing aptitude of different rice cultivars for the preparation of Jeung-pyun, its texture was analyzed by Instron, hardness, cohesiveness, elasticity, gumminess and chewiness of Jeung-pyun made of rice showed the significant relationship with the amylose content. Hardness was increased during retrogradation of product, but the relationship between hardness and amylose content due to not only difference in amylose content but also difference in structural characteristics of starch. In analysis of relationship between structure of rice starch and mechanical properties of Jeung-pyun during retrogradation elasticity did not show any relationship before retrogradation bur during retrogradation showed significant correlation. With these result, it can be suggested that the degree of branch of the amylopectin may effect on elasticity during retrogradation. However hardness, cohesiveness, gumminess and chewiness which were significant different before retrogradation, showed some correlation with structure of rice starch during retrigradation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.1
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• pp.27-32
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• 2006

Thermoplastic elastomer(TPE) has many advantages such as high flexibility, high elasticity and high elongation, etc. TPE is easily molded as plastic materials, therefore, many TPE parts are applied as home appliances and mechanical parts. However, its mechanical properties would be changed by injection molding conditions such as melt temperature, mold temperature, injection pressure and holding pressure, etc. In this study, the influences of the injection molding condition on the mechanical properties as tensile strength, hardness of thermoplastic vulcanizates(TPVs), which is one of the TPE, were investigated. By the injection molding experiment, the molding's tensile strength and hardness was influenced on the melt temperature and composition ratio of PP and EPDM. The morphology of moldings were shown by the scanning electron microscope.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3923-3927
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• 2010

Primary charging roller rotated with contacting surface of OPC drum and take charge OPC drum. Owing to this reason, primary charging roller is made by elasticity substance with electric conduction. Properties of charging and image is changed by class of coating, method of coating and environment. This study developed coating material and coating method to make Image Forming of High- quality.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.3
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• pp.149-154
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• 2002

In this paper, we propose a new graphic deformation algorithm for haptic interface system. Our deformable model is based on non-linear elasticity, anisotropy behavior and the finite element method. Also we developed controller for high-speed communication. The proposed controller is based on the PCI/FPGA technology, which could progress the capability of the position calculating and the force data transmitting. The haptic system is composed of the 6DOF force display device, the high-speed controller, HIR library for 3D graphic deformation algorithm and the haptic rendering algorithm. The developed system will be used on constructing the dynamical virtual environment. We demonstrate the relevance of this approach for the real-time simulating deformations of elastic objects. To show the efficiency of our system, we programmed the simulation of force reflecting. As the result of experiment, we found that it has high stability and easy to control for deformable object than some other systems.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.399-402
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• 2003

This study is performed to examine the physical and mechanical properties of the high strength concrete using recycled aggregate. The recycled aggregate is replaced by 0%, 25%, 50%, 75%, 100% of natural crushed aggregate. The compressive strength of the concrete used recycled aggregate is shown in more than $400kgf/cm^2$ at the curing age 28 days. But the pulse velocity and dynamic modulus of elasticity are decreased with increasing the content of recycled aggregate. Accordingly, these recycled aggregate concrete can be used for high strength concrete.

• Journal of Industrial Technology
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• v.24 no.B
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• pp.73-81
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• 2004

The development of efficient and precise handling of an liquid crystal display (LCD) panel has been addressed as the sizes of LCD panels become much larger than ever. The majority part of LCD panel handling is conducted by industrial robots for the cost reduction and the quality control. A challenging problem, vibration of the panel, can be found when the robots are utilized for handling LCD panels. The vibration causes the poor product precision and the low productivity. The characteristics of LCD panels, which are the high size-to thickness ratio, the high elasticity, and the high brittleness, are the major sources of the vibration This paper introduces the vibration attenuation techniques to overcome the difficulties encountered in the LCD production using the industrial robots.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.685-686
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• 2011

There have been intensive and continuous efforts in the field of DLC coating process because of their feature, like high hardness, high elasticity, abrasion resistance and chemical stability and have been applied widely the industrial areas. In this report, tungsten carbide(WC) mold core was manufactures using high performance precision machining and the efforts of DLC coating on the surface roughness and SEM of WC mold was evaluated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.140-140
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• 2010

There have been intensive and continuous efforts in the field of DLC coating process because of their feature, like high hardness, high elasticity, abrasion resistance and chemical stability and have been applied widely the industrial areas. In this report, tungsten carbide(WC) mold core was manufactures using high performance precision machining and the efforts of DLC coating on the surface roughness and SEM of WC mold was evaluated.