• Structural Engineering and Mechanics
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• 제60권5호
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• pp.829-849
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• 2016

In this paper, experimental as well as numerical analysis of Glass Fiber Reinforced Polymer (GFRP) laminated composite has been presented under ballistic impact with varying projectile nose shapes (conical, ogival and spherical) and incidence velocities. The experimental impact tests on GFRP composite plate reinforced with woven glass fiber ($0^{\circ}/90^{\circ}$)s are performed by using pneumatic gun. A three dimensional finite element model is developed in AUTODYN hydro code to validate the experimental results and to study the ballistic perforation characteristic of the target with different parametric variations. The influence of projectile nose shapes, plate thickness and incidence velocity on the variation of residual velocity, ballistic limit, contact force-time histories, energy absorption, damage pattern and damage area in the composite target have been studied. The material characterization of GFRP composite is carried out as required for the progressive damage analysis of composite. The numerical results from the present FE model in terms of residual velocity, absorbed energy, damage pattern and damage area are having close agreement with the results from the experimental impact tests.

• 한국표면공학회지
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• 제42권2호
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• pp.59-62
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• 2009

Antireflection pattern, moth-eye structure, was fabricated on lens using Ultra Violet nanoimprint lithography and flexible template. Ni template with conical shaped structure was used as a master template to molding. The flexible poly vinyl alcohol template was fabricated by molding. This poly vinyl alcohol template was used as an imprint template of imprint at lens. Using Ultra Violet nanoimprint lithography and poly vinyl alcohol template, polymer based moth-eye structure was formed on lens and its transmittance was increased up to 94% from 92% at 550 nm wavelength.

• Macromolecular Research
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• 제17권7호
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• pp.464-468
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• 2009

Gelatin nanoparticles derived from bovine or porcine have been developed as various types of drug delivery system, and they need to be cross-linked to maintain their physicochemical properties in aqueous environments. Although gelatin is a widely used material in pharmaceutical industries, the safety issue of animal-origin gelatins, such as transmissible mad cow disease and anaphylaxis, remains to be solved. The purpose of this study was to prepare type A gelatin (GA) nanoparticles by modified, two-step, desolvation method and compare the toxicity of the resulting GA nanoparticles with recombinant human gelatin (rHG) nanoparticles. The GA nanoparticles were characterized, and drug loading and release pattern were measured. FITC-BSA, a model protein, was efficiently loaded in the nanoparticles and then released in a biphasic and sustained release pattern without an initial burst. In particular, the cell viability of the GA nanoparticles was less than that of the rHG nanoparticles. This finding suggests that rHG nanoparticles should be considered as an alternative to animal-origin gelatin nanoparticles in order to minimize the safety problems.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1122-1124
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• 2009

Organic thin-film transistors (OTFTs) were fabricated by using the transfer patterning method. In order to remove Au pattern easily, UV-curable polymer mold was surface treated. Au source/drain (S/D) pattern was transferred to insulator-coated substrate surface. Fabricated OTFTs were compared to OTFTs using vacuum-deposited Au S/D. Additionally, transistor diodes were characterized.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1042-1044
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• 1996

The use of fuzzy theory in task of pattern recognition may be applicable gases and odours classification and recognition. This paper reports results obtained from fuzzy c-means algorithms to patterns generated by odour sensing system using an array of conducting polymer sensors, for volatile chemicals. For the volatile chemicals clustering problem, the three unsupervise fuzzy c-means algorithms were applied. From among the pattern clustering methods, the FCMAW algorithm, which updated the cluster centres more frequently, consistently outperformed. It has been confirmed as an outstanding clustering algorithm throughout experimental trials.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.2080-2081
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• 2007

In this paper, the polymer insulators which had been used for electrical insulation were investigated surface leakage current and deterioration pattern. Because the electrical fault took place at the dust occurrence area due to environmental pollution. In particular, the dust accumulates easily on insulation material which is exposed an external long time. The leakage current brings out electrical fault after all. Also, it is need to variation of material and shape to repress a leakage current on electrical material. In this paper, we measured a leakage current on electrical material of facilities by dust, and in experiments the prevention to electrical fault was studied.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.265.2-265.2
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• 2013

We fabricate poly(3,4-ethylenedioxythiopene patterns using liquid-bridge-mediated nanotransfer (LB-nTM) printing via vapor phase polymerization (VPP). LB-nTM printing method can simultaneously enable the synthesis, alignment and patterning of the nanowires from molecular ink solutions. Two- or three-dimensional complex structures of VPP-PEDOT were directly fabricated over a large area using many types of molecular inks. VPP method is a versatile technique that can be used to obtain highly conducting coatings of conjugated polymer on both conducting and non-conducting substrates. The PEDOT patterns has analyzed crystallinity from X-ray diffraction pattern and select-area diffraction patterns. In addition, the PEDOT pattern has high conductivity compared other conducting polymers.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.70-71
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• 2014

In this paper, an advanced charging strategy for improving the charging performance of the Li-ion polymer battery is proposed, which is based on the battery characteristic. Simulation results show that the proposed charging current pattern can improve the charging speed of battery in comparison with the standard CC-CV (constant current - constant voltage) charging strategy and the pulse-charging strategy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.423-424
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• 2009

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.76-76
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• 2007

Several kinds of photo-chromic polymers containing push-pull structure were synthesized and investigated on optical patterning by photo-induced surface relief gratings (SRG) technique. The azobenzene segment was introduced as a functional group for a photo-triggered tran-cis isomerization. Consequently, we have fabricated micro-size regular pattern by one-step process without photo-mask.