1,721,226 research outputs found
Effect of Permeability on Spread-Splash Transition Criterion in Drop Impingement against Porous Substrate - A Preliminary Report
No full textInterfacial characteristics of plasticized polymer electrolyte based on crosslinked polymer electrolyte
No full textPhotoinduced low refractive index in a photosensitive organic inorganic hybrid material
No full textA new organic-inorganic hybrid material, that shows photoinduced reduction of refractive index as well as volume contraction, has been prepared using a sol-gel method. Whereas previous photosensitive materials show a photoinduced increase in refractive index, this hybrid material shows a significant decrease in refractive index via the decomposition of methacrylate on light irradiation. Moreover, this hybrid material is patternable. The reduction of refractive index measured with a prism coupler was about 0.045, with a low refractive index value of 1.385 being observed. The structural change of the hybrid material on UV-light irradiation as monitored by FT-IR and energy dispersive X-ray spectroscopy (EDS) is investigated. Direct imprinting of the organic inorganic hybrid material without any further steps (wet etching, thermal curing, or UV fixing) is also performed utilizing the volume contraction on light irradiation
Ultraviolet-nanoimprint of 40 nm scale patterns using functionally modified fluorinated hybrid materials
No full textPhoto-curable fluorinated organic - inorganic hybrid materials (F-hybrimers) present high modulus, low surface tension, low shrinkage, and high etching resistance. These are essential properties as a mould and as a resist for nanoimprint lithography (\NIL). In order to control the properties of the fluorinated hybrimer, in this study it is modified by the optimal addition of appropriate acryl monomers as a mould and as a resist material for NIL. Accordingly, the viscosity in terms of the resist material and the modulus in terms of the mould material are modulated ( low v F-hybrimer and flexible F-hybrimer). Finally, 30 - 40 nm half-pitch line patterns are imprinted, using identically modified F-hybrimer material systems as a mould and a resist.This research has been supported by the Korea Science and
Engineering Foundation (KOSEF; Grant No. R01-2003-000-
10125-0) and the Brain Korea 21 project
Mixed-Mode Interfacial Fatigue Characteristics of Composite/Metal Interface of Bimaterials
No full textNanopatterning of photonic crystals with a photocurable silica-titania organic-inorganic hybrid material by a UV-based nanoimprint technique
No full textUV patternable high refractive index inorganic-organic hybrid materials prepared by sol-gel process can be nanoimprinted in order to get photonic crystal nanopatterns. Non-hydrolytic sol-gel process can make a UV curable and relatively high refractive index hybrid material, which can be cured without a significant shrinkage for nanoimprinting. Sol-gel process of heterogeneously functionalized silicon alkoxides can make the organically modified inorganic Si-O-Ti network very well. The UV-based nanoimprint technique utilizes transparent templates and UV curable high refractive index materials to allow pattern replication at room temperature and very low pressure. UV-based nanoimprint technique is an efficient way to fabricate this sort of polymeric photonic crystal nanostructures.This work is supported by the Sol–Gel Innovation Project
(SOLIP) of the Ministry of Commerce, Industry and Energy of
Korea
Misalignment estimation and compensation for robotic assembly with uncertainty
No full textThe complexity and uncertainty of the cross-sectional shape of the parts to be mated is one of the main reasons that misalignment between them occurs in assembly processes. Misalignment cannot only give rise to assembly failure but also cause damage to the parts or a robot due to large contact force. Therefore, misalignment sensing and compensation is essential for successful assembly operation. In this paper, we propose a novel misalignment estimation and compensation method which does not need any advance information on the cross-sectional shapes of the mating parts. This method utilizes a f - r transformation and an M-estimation pattern matching technique with misalignment images of a peg and a hole taken by an omni-directional visual sensing system during assembly. At every sampling instant during assembly action, it furnishes information on the relative position and orientation between the mating parts, and thus helps to estimate and compensate any possible misalignment between them. Also, a series of experiments are performed with a couple of peg-in-hole tasks, and the results are discussed. The experimental results show that the proposed method is effective for misalignment compensation in robotic assembly even though there is no prior information on part geometry and the images are very noisy
Flexible Film Optical Waveguide with Little Bending Loss Fabricated by UV Moulding of Sol-Gel Hybrid Materials
No full textForeign Investors and Corporate Governance in Korea
No full textThis paper has two aims. The first aim is to investigate whether poor corporate governance negatively affects equity participation by foreign portfolio investors. The second aim is to investigate whether firm-level efforts to improve on corporate governance attract more foreign portfolio investments. The evidence indicates that foreign equity ownership is negatively associated with ownership concentration and positively associated with firm’s efforts to improve on corporate governance. Interestingly, however, domestic investors behave differently from foreign investors in that the latter group appears to be less sensitive to firm-level corporate governance than the former group
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