• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.3
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• pp.46-51
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• 2004

Nowadays, plastic industry has needed to produce parts that require high precision and quality. To make a high precision and quality part, before injection molding, plastic material in investigated about their properties such as shrinkage, warpage, etc. In this study, experiments were conducted with PP(polypiopylene) to figure out shrinkage behavior according to three type aspect ratio of samples. The injection speed that affects on shear late, molecular orientation within plastic part was determined as main variable of experiment. As a result of experimental study, part shrinkage had a tendency to be decreased by increasing injection speed and aspect ratio of samples.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.444-447
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• 2005

In recent industry, according to pursuit the miniaturization and high-precision of machine part with development of new technology as If, BT the development of mold manufacturing technology for mass production is accompanied. In this study, after executing the injection molding process of micro structure on the plate which the aspect ratio is 10, the characteristic of each molding condition is investigated by observing the filling height.

• Design & Manufacturing
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• v.2 no.2
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• pp.6-9
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• 2008

Injection molding is representative process of plastic production. Most of numerical analyses for injection molding have been based on the Hele Shaw's approximation: two-dimensional flow analysis. The present work covers numerical analyses of injection molding using three-dimensional solid elements. The accuracy of the analysis results has been verified through some numerical examples in comparison with the various conditions. In this study, moldflow software was used to analyze the cooling analysis. The results of cooling analysis and testing catapult were compared for plastic products.

• Steel and Composite Structures
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• v.19 no.3
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• pp.777-787
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• 2015

Production and properties of metal matrix composites reinforced with an in-situ high aspect ratio $AlB_2$ flake have been investigated. Boron 2.2wt.% was dissolved in pure Al and Al-Cu alloy at $1300^{\circ}C$ by adding directly boron oxide which resulted in 4 vol.% reinforcing phase. The in-situ $AlB_2$ flake concentration was increased up to 30 vol.% in order to increase the tensile strength of the composites. Hardness, compressive strength and tensile strength of the composite were measured and compared with their matrix. Results showed that 30 vol.% $AlB_2/Al$ composite show a 193% increase in the compressive strength and a 322% increase in compressive yield strength. Results also showed that ductility of composites decreases with adding $AlB_2$ reinforcements.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1815-1818
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• 2006

Imogolite which has chemical composition, $(HO)_3Al_2O_3SiOH$, was synthesized with orthosilicate acid and aluminium chloride at low pH solution. It has extremely large aspect ratio with an external diameter of 2nm and the length of a few micrometers. The high aspect ratio of the imogolite could make the material as the filler for the high strength fiber and as the wire for the electronic applications. Here, Imogolite that derives considerable microporosity from a nanometer-sized tubular structure has been modified with a conducting polymer, polypyrrole. Its bonding and wiring structure were confirmed by IR and TEM. The measured conductivity after modification with polypyrrole increased with polypyrrole thickness at various voltage conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.138-138
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• 2000

Kinetic behaviors of homoepitaxial growth on Ni(110) surface was studied at the growth-temperature ranges 290~380 K with scanning tunneling microscopy. At low temperature (~290 K), deposited Ni grows layer-by-layer mode in the first several layers with one-dimensional islands but eventually (at > monolayers) forms three-dimensional islands througy the kinetic shortening of the average length of one-dimensional islands. At the intermediat temperature (~340 K), the three-dimensional islands were observed to be I) regular mesa-like structure with high aspect ratio (~1:10) at ~15 monolayer, ii) hut-like structure with low aspect ratio (~1:1.5) at ~35 monolayer, and iii) rounded mound structure at ~55 monolayers, due to the competition of kinetic and energetic terms. At the high temperature (~ 380 K), the flat surface with layer-by-layer mode was observed up to 50 monolayers. Microscopic orgins for the observations will be discussed on the basis of kinetic Monte Carlo simulations.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.1
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• pp.32-37
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• 2023

In this study, in order to propose a integrity evaluation for type IV high aspect ratio hydrogen storage vessel, a numerical analysis of the hoop tensile test and pressure test was performed using FEM software, and the results of the actual physical property test were reviewed. The property test and numerical analysis were compared, and very similar results were obtained with deviations of maximum tensile strength of 4.75% and fiber direction stress of 5.39%.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.339-344
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• 2001

The present study investigates convective heat/mass transfer and flow characteristics in wavy ducts of primary surface heat exchanger. Experiments using a naphthalene technique are carried out to determine the local transfer characteristics for flow in the corrugated wall duct. The aspect ratios of the rectangular duct cross-section are 7.3, 4.7 and 1.8 with a corrugation angle of $145^{\circ}$. The Reynolds numbers, based on the duct hydraulic diameter, are ranged from 1000 to 5000. The local heat/mass transfer measurement is conducted in the spanwise directions. The results show that Tayler-Gortler vortices exist on the pressure surface. Flow separation on the suction surface appears at a high Reynolds number resulting in a sharp decrease in the local transfer rates, but relatively high transfer rates are obtained in the reattachment region.

• Korean Journal of Metals and Materials
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• v.49 no.4
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• pp.334-341
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• 2011

The mechanism behind super-filling of high-aspect-ratio features with Cu by catalyst-enhanced chemical vapor deposition (CECVD) coupled with plasma treatment is described and the metrology required to predict the filling feasibility is identified and quantified. The reaction probability of a Cu precursor was determined as a function of substrate temperature. Iodine adatoms are deactivated by the bombardment of energetic particles and also by the overdeposition of sputtered Cu atoms during the plasma treatment. The degree of deactivation of adsorbed iodine was experimentally quantified. The quantified factors, reaction probability and degree of deactivation of iodine were introduced to the simulation for the prediction of the trench filling aspect by CECVD coupled with plasma treatment. Simulated results show excellent agreement with the experimental filling aspects.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.155-155
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• 1992