Electrospinning is a versatile and straightforward method for the formation of continuous thin fibers and is based on an electrohydrodynamic process from polymer solutions and melts. To improve the throughput of electrospinning and the quality of the electrospun thin fibers, an in-depth understanding of the fiber formation process is required. In the present study, we attempted to quantitatively analyze the bending instability of an electrified thin jet during electrospinning. The electrified-jet flying phenomenon from the spinneret to the substrate was investigated by high-speed camera observation and electromagnetic and kinetic analyses, i.e., the flying velocity of the electrified jet was measured, and the electric potential was obtained from finite element method analysis of an electric field. The charge density and diameter of the electrified jet in the bending instability region during electrospinning were determined by solving the equation of motion.

Nanoimprint lithography has advantages such as good resolution, CD uniformity and LER. However, nanoimprint lithography involves risks. In particular, defectivity is the most critical issue for nanoimprint lithography. Above all, the "non-fill defects" dominate such defects for UV nanoimprint.At the filling process of imprint resist, the capillary force that occurs between an imprint-resist and surface of template plays an important role. Our experience, suggests there is a relationship between the filling characteristics and pattern size of template. We also think the resist properties and the environmental conditions such as atmosphere pressure play important roles in the filling process. This paper explains the filling process dependency on the properties mentioned above.We analyzed the filling process using fluid simulation. At first, we assumed several pattern sizes with the same pattern height. Then, the filling times were estimated for each pattern size with various resist properties and the environmental conditions. An important attribute of our simulation model is the consideration accorded to the dissolution of gas between the template and imprint resist.As a result, the filling time of smaller pattern was found to be shorter than that of larger pattern. The assumed patterns are space and via on template ranging in size from 22nm width to 1000nm-width. The pattern height is 60nm.In this paper, we studied characteristics of filling mechanism by using fluid simulation. The relations between CD and filling time were obtained. We found that the gas dissolution rate is the dominant parameter for filling time.

At present, epoxy resin is applied during the manufacturing of more compact and thinner components for the packaging of electronic and other devices. Epoxy resin has superior properties in terms of heat resistance, insulation, and strength; however, defects such as deformations and cracks often occur because of stress concentration. It is important to determine the inner stress of resin solidification for molding processes. Through a combination of numerical analyses of heat generated due to chemical reactions and experiments on shrinkage and strain that occur during hardening of epoxy resin, it becomes possible to analyze the stress generated due to hardening shrinkage. The developed analytical method can contribute to the realization of highly reliable components made of epoxy resin.

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This paper reports the effects of structural parameters on organic liquid impregnation behavior into nanofibrous (NF) polymer membranes. The NF membranes were prepared from organic liquidphilic polymers, poly(amide-imide)s (PAIs), by electrospinning. The impregnation velocity of the organic liquid, ethylmethylcarbonate, into the as-spun PAI NF membranes with diameters ranging from 400 to 900 nm was approximately 10–20 times higher than that into commercial cellulose nonwoven membranes. Our theoretical analyses based on the Kozeny–Carman equation and multivariate statistics clearly indicate that in addition to the porosity of the membranes, the variation in fiber diameter as well as the average fiber diameter is a crucial factor for controlling the liquid impregnation behavior.