• Journal of Powder Materials
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• v.16 no.2
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• pp.85-90
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• 2009

Magnesium and its alloys are attractive as light weight structural/functional materials for high performance application in automobile and electronics industries due to their superior physical properties. In order to obtain high quality products manufactured by the magnesium powders, it is important to control and understand the densification behavior of the powders. The effect of the sheath surrounding the magnesium powders on the plastic deformation and densification behavior during equal channel angular pressing was investigated in the study by experimental and the finite element methods. A modified version of Lee-Kim's plastic yield criterion, notably known as the critical relative density model, was applied to simulate the densification behavior of magnesium powders. In addition, a new approach that extracts the mechanical characteristics of both the powder and the matrix was developed. The model was implemented into the finite element method, with which powder compaction under equal channel angular pressing was simulated.

• Korean Journal of Materials Research
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• v.16 no.6
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• pp.355-359
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• 2006

Fine silica powders were synthesized via w/o emulsion method using sodium silicate, ammonium sulfate, Triton N-57, and cyclohexane as silica source, precipitating agent, surfactant, and oil phase, respectively. The powders were prepared under a conventional process and an ultrasonic process using the same reactants at room temperature for 1 hr varying the concentration of $Na_2SiO_3$ solution and the mol ratio of $H_2O$/surfactant, respectively. The particle size of the silica powder was reduced with decreasing the concentration of sodium silicate solution and with increasing the mol ratio of $H_2O$/surfactant under with and without ultrasounds. The size of powder with ultrasounds was smaller than that without ultrasounds, which indicates that the application of ultrasound in the synthesis of silica powder is an efficient way to reduce particle size.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.17-22
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• 2002

This Waterproofing Material which mainly consisted of 2 components of waste tire chip powder and waste glass powder. This Study is abut development of waterproofing Material, There is not tried in domestic. The most Motive of this Study wishes to recycle resources and get the economic performance for waterproofing Material The result of this Study is as followings. (1) Dense waterproofing floor is formed between waste tire chip by Coupling Agent(the most effective method to encourage adhesive strength and raise cohesion of material by combination.) (2) Expected to bring effect to shorten construction period at spot application potentially space-time in moisture aspect. Also, shortening effect of construction period and spot work are considered to be gone efficiently selecting pre-mix construction method. (3) This development Waterproofing material has elasticity that nature side compatibility of cement ingredient and plastic Emulsion have when utilize and constructs waite resources (being waste tire chip and waste glass powdered).

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.81-85
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• 2002

This study was carried out to investigate the effect of organic fertilizer(OM-1 : $300kgha^{-1}$, OM-2 : $600kgha^{-1}$), microorganism(ML : liquid form, MP : powder form) and seaweed extract ; ascophyllum nodosum(AF : foliar application, AI ; irrigation) on the growth and yield of the chinese cabbage. At the treatment of organic fertilizer OM-2 have appeared the best yield. According to the application of microorganism appeared certainly increasing yield of cabbage by application of powder form. The excess application of organic fertilizer OM-2 should not be occurred fertilizer damages and increased on the growth and yield by use of microorganism, In application of sewweed extract treatment, the cabbage yield increased by irrigation method.

• Journal of Powder Materials
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• v.24 no.5
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• pp.351-356
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• 2017

Tin dioxide nanoparticles are prepared using a newly developed synthesis method of plasma-assisted electrolysis. A high voltage is applied to the tin metal plate to apply a high pressure and temperature to the synthesized oxide layer on the metal surface, producing nanoparticles in a low concentration of sulfuric acid. The particle size, morphology, and size distribution is controlled by the concentration of electrolytes and frequency of the power supply. The as-prepared powder of tin dioxide nanoparticles is used to fabricate a gas sensor to investigate the potential application. The particle-based gas sensor exhibits a short response and recovery time. There is sensitivity to the reduction gas for the gas flowing at rates of 50, 250, and 500 ppm of $H_2S$ gas.

• Journal of Powder Materials
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• v.26 no.1
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• pp.28-33
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• 2019

The gas sensor is essential to monitoring dangerous gases in our environment. Metal oxide (MO) gas sensors are primarily utilized for flammable, toxic and organic gases and $O_3$ because of their high sensitivity, high response and high stability. Tungsten oxides ($WO_3$) have versatile applications, particularly for gas sensor applications because of the wide bandgap and stability of $WO_3$. Nanosize $WO_3$ are synthesized using the hydrothermal method. As-prepared $WO_3$ nanopowders are in the form of nanorods and nanorulers. The crystal structure is hexagonal tungsten bronze ($MxWO_3$, x =< 0.33), characterized as a tunnel structure that accommodates alkali ions and the phase stabilizer. A gas detection test reveals that $WO_3$ can detect acetone, butanol, ethanol, and gasoline. This is the first study to report this capability of $WO_3$.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.1-8
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• 2016

This study aimed to enhance the applications of dates as a food material that can be utilized and stored easily by improving the inefficient process of the traditional cooking procedure. To this end, this study investigated the physico-chemical and nutritional properties of jujube pulp powder, and compared the traditional and newly developed methods of making yakbap, yakpyon, and jujube porridge. According to the analysis of physical and chemical properties, the jujube pulp powder contained 5.4% moisture, 2.6% crude ash, 6.6% crude protein, 0.35% crude fat, and 4.7% crude fiber. The water activity was 0.95% in jujube pulp while it was 0.24% in jujube pulp powder. In addition, the jujube pulp powder had a total sugar content of 70.4% and reducing sugar content of 6.3%. The vitamin C was content was estimated to be 68.5 mg/100 g in the jujube pulp powder and the jujube pulp contained 6.2 g/100 g of dietary fiber. Major minerals were K, Mg, and Ca. After appointing jujube pulp powder (new method) to a test group and jujube pulp (traditional method) to a control group, the sensory evaluation and acceptance testing were conducted for yakbap, yakpyon, and jujube porridge. As a result, there was no significant difference in any sensory factors tested (p<0.05). It was found that making and storing jujube pulp powder by drying jujube pulp is a useful way of utilizing jujube because Yakbab, Yakpyun and jujube porridge were found to have a relatively good appearance, color, flavor, taste, texture and overall acceptance.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.04a
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• pp.50-50
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• 2006

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.99-102
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• 2002

The BSCCO superconductor materials of using Self-propagating High-temperature Synthesis (SHS) were studied. Mechano-chemical activation - as a pre-treatment of the reactants mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product. In this paper as an effort for fabricating the SHSed BSCCO superconductor powder SHS method was considered to application in the synthesis of superconducting materials.

• Journal of Powder Materials
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• v.10 no.3
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• pp.151-156
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• 2003

In the present work some properties of nanopowders and possible areas of their applications are discussed. Main attention is paid to the use of nanodispersed powders (NDP) in new materials production technologies.