• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.360-360
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• 2006

Zein protein is one of the best biopolymer for edible film making and polyols are convenient plasticizers for biopolymers. Sorbitol, glycerol and manitol at three levels (0.5, 0.7, 1g/g of zein) were used as plasticizers. Rheological and thermal properties of zein resins were studied for determining their plasticization effectiveness. Sorbitol and glycerol had good plasticizing effects and could decrease viscoelastic modulus of zein resins considerably, but manitol was not as effective as them. Effects of plasticizers on thermal properties of resins were investigated by DSC at -100 to $150^{\circ}C$. No crystallization and melting peaks related to zein resin and plasticizers were observed. Thermograms showed that polyolic plasticizers and zein resin remained a homogeneous material throughout the cooling and heating cycles.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.159-164
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• 2005

The Hot Embossing Lithography(HEL) as a method fur the fabrication of the nanostructure with polymer is becoming increasingly important because of its simple process, low cost, high replication fidelity and relatively high throughput. In this paper, we carried out experimental studies and numerical simulations in order to understand the viscous flow of the polymer (PMMA) film during the hot embossing process. To grasp the characteristics of the micro patterning rheology by process parameters (embossing temperature, pressure and time), we have carried out various experiments by using the nickel-coated master fabricated by the deep RIE process and the plasma sputtering. During the hot embossing process, we have observed the characteristics of the viscoelastic behavior of polymer. Also, the viscous flow during the hot embossing process has been simulated by the continuum based FDM(Finite Difference Method) analysis considering the micro effect, such as a surface tension and a contact angle.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.4
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• pp.52-57
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• 2001

The flexural vibration of aluminum beams with active and passive constrained-layer damping has been investigated experimentally to design a structure with maximum possible damping capacity. Piezoelectric film is used as a sensor and piezoceramic as an actuator for the negative velocity feedback control. The experimental results are compared with those by the finite element analysis. This paper shows the effectiveness of active constrained-layer damping treatment through experiments, and we have carried out an experiment to study the effect of beam thickness.

• Journal of Dairy Science and Biotechnology
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• v.38 no.4
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• pp.189-196
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• 2020

Milk proteins, such as casein and whey protein, exhibit significant potential as natural emulsifiers for the preparation and stabilization of emulsion-based delivery systems. This can be attributed to their unique functional properties, such as the amphiphilic nature, GRAS (generally recognized as safe) status, high nutritional value, and viscoelastic film-forming ability around oil droplets. In addition, milk protein has been used as a coating material in emulsion-based delivery systems to protect bioactive compounds during food processing and storage owing to its unique functional properties. These properties include the ability to bind lipophilic bioactive compounds and antioxidant activity. In this review, we present the use of milk proteins as emulsifiers for the formation of emulsions and food applications of milk protein-stabilized emulsion delivery systems.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.85-86
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• 2020

In securing durability of underground structure non-exposed waterproof materials, the company aims to improve durability of waterproof materials by studying more realistic weather conditions than KS standards and developers' durability standards. Analyzing the actual climate data in Korea and the temperature of the basement layer, it is a waterproofing sheet method, a self-adhesive sheet method in which a film and a compound, which are currently widely used as underground water-proofing, and a self-adhesive waterproofing sheet method, etc. We would like to present the guidelines necessary to prevent the temperature situation and waterproof defects that are ideal for setting the endurance conditions later.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.547-553
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• 2008

To achieve the ideal performances of paint film, resins and hardeners have to be chosen and designed in a proper way depending on the exposure circumstance of substrate and the requested physical properties. Six different kinds of clear paints were made in this experiment using alkyd polyol, polyester polyol, polyester modified acrylic polyol and another 3 acrylic polyol resins whose $T_g$ and OH value were partially modified. Then the tests for chemical, physical, and mechanical properties were measured after forming the paint films using aliphatic and aromatic polyisocyanate. The viscosity and elasticity of paint film were then measured in terms of gel point and $tan{\delta}$ using Rheometer and DMA. Through this viscoelastic characteristic test of polyurethane resin, we were able to choose the adequate resins and hardeners which are the most important in the top and primer painting system of urethane paint and, as a result of observing the physical, mechanical, and chemical properties of paint film by urethane, we have finally reached the conclusion that we could apply the proper polyol to top and primer paint for developing the polyurethane paint system.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.59-64
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• 2022

Effects of film stack structure and peeling rate on the peel strength of screen-printed (SP) Ag/polyimide (PI) systems were investigated by a 90° peel test. When PI film was peeled at PI/SP-Ag and PI/SP-Ag/electroplated (EP) Cu structures, the peel strength was nearly constant regardless of the peeling rate. When EP Cu was peeled at EP Cu/SP-Ag/PI structure, the peel strength continuously increased as peeling rate increased. Considering uniaxial tensile test results of EP Cu/SP-Ag film with respect to loading rate, the increase of 90° plastic bending energy and peel strength was attributed to increased flow stress and toughness. On the other hand, viscoelastic PI film showed little variation of flow stress and toughness with respect to loading rate, which was assumed to result in nearly constant 90° plastic bending energy and peel strength.

• Korea-Australia Rheology Journal
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• v.21 no.2
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• pp.109-117
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• 2009

Absorption rate of carbon dioxide was measured in the aqueous xanthan gum (XG) solution in the range of 0~0.15 wt% containing diisopropanolamine (DIPA) of $0{\sim}2\;kmol/m^3$ in a flat-stirred vessel with an impeller of 0.05 m and agitation speed of 50 rpm at $25^{\circ}C$ and 101.3 kPa. The volumetric liquid-side mass transfer coefficient ($k_La$) of $CO_2$, which was obtained by the measured physical absorption rate, was correlated with the viscosity and the elastic behavior of XG solution such as Deborah number as an empirical formula. The chemical absorption rate of $CO_2$ ($R_A$), which was estimated by the film theory using the measured $k_La$ and the known kinetics of reaction between $CO_2$ and DIPA, was compared with the measured rate. The aqueous XG solution with elastic property of non-Newtonian liquid made $k_La$ and $R_A$ increased compared with Newtonian liquid based on the same viscosity of the solution.

• Korea-Australia Rheology Journal
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• v.15 no.3
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• pp.125-130
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• 2003

The emulsion stability of cosmetic creams based on the water-in-oil (W/O) high internal phase emulsions (HIPEs) containing water, squalane oil and cetyl dimethicone copolyol was investigated with various compositional changes, such as electrolyte concentration, oil polarity and water phase volume fraction. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The slope change of complex modulus versus water phase volume fraction monitored in the linear viscoelastic region could be explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsions: the greater the increase of complex modulus was, the more the coalescence occurred and the less consistent the emulsions were. Emulsion stability was dependent on the addition of electrolyte to the water phase. Increasing the electrolyte concentration increased the refractive index of the water phase, and thus decreased the refractive index difference between oil and water phases. This decreased the attractive force between water droplets, which resulted in reducing the coalescence of droplets and increasing the stability of emulsions. Increasing the oil polarity tended to increase emulsion consistency, but did not show clear difference in cream hardness among the emulsions.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.374-379
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• 2017

In vehicle to pedestrian accidents, cracks occur in the vehicle laminated glass due to impact of a pedestrian's head. In this study, FMH(Free Motion Headform) was used to experiment on and analyze the crack patterns on a vehicle laminated glass that collides with an adult headform at speeds of 20 km/h, 30 km/h, and 40 km/h, respectively. Applying the acquired experimental data and material property of the vehicle laminated glass to the structural analysis program LS-Dyna, we could develop the FE model of vehicle laminated glass similar to real vehicle laminated glass. We could estimate the head impact velocity and pedestrian's vehicle impact velocity using the Madymo program.