In this study, changes in the amount of potassium chloride liquid phase used for the molten‐salt synthesis of strontium ferrite were examined to understand the transition of the growth mechanism with temperature. The results of this investigation indicate that an increase in reaction temperature from 900° to 1200°C caused the particle shapes to become nearly spherical. In addition, the particle size decreased as the relative amount of liquid increased. The growth process of the strontium ferrite particles in the molten salt appears to have undergone a transition from an interfacial, reaction‐controlled mechanism to a diffusion‐controlled mechanism as temperature is increased.
Highly ordered pattern formation of block copolymers (BCPs) within nanoscale templates is of great interest for generating diverse ordered nanostructures. Here, introduced is a combined methodology of nanotransfer printing (nTP) and BCP self‐assembly to guide the formation of spherical nanodots within a printed crossbar nanotemplate. By successfully accommodating poly(styrene‐b‐dimethylsiloxane) (PS‐b‐PDMS) BCPs in the guiding metallic crossbar nanotemplate (≈30 × 30 nm2), a well‐organized array of single‐domain PDMS spheres (≈10 nm) with a square symmetry is successfully obtained in an extremely short annealing time (<5 s). The self‐consistent field theory simulation results theoretically explain the spontaneous one‐to‐one accommodation of PDMS spheres in the confined area of the crossbar template. This approach can potentially be extended to the many other BCP materials and morphologies to diversify the geometry of self‐assembled BCP and/or transfer‐printed nanopatterns for various types of nanodevice applications.
Dielectric properties of low-loss dielectric materials are investigated with variation of silica filler which is known to be general filler in PCB composite. With comparison of dielectric losses of various filler materials in use of BCB resin, it could be known that crystalline cristobalite was superior to other crystalline or amorphous silica-base materials and reduced dielectric losses in the composite with resin. And dielectric properties of composite with the variation of filler quantity showed that amorphous silica and quartz increased dielectric loss as their quantities increased, while cristobalite increased little. As quantity of crystalline cristobalite phase increases in cristobalite/quartz intermediates, dissipation factor decreases.
Composite specimens with resin contents of 33.5%, 35.4%, and 35.9%, respectively, were manufactured by controlling the type of subsidiary material used in the bagging process for a composite material having the same composition.The effect of controlling the resin content on the microstructure and mechanical properties of composite specimens was investigated. The flow of resin and air during the cure process was inferred and explained by connecting it with the microstructure. Specifically, the behavior of the resin determined the thickness, density, and void of the composite laminate, which acted as a factor causing the difference in mechanical properties of the composite materials. As the resin content increased, there was no significant difference in tensile strength, but Young's modulus decreased. In the case of the compression test, there was a difference in mechanical properties due to the combined effect of the reinforcement and the resin. The maximum compressive strength value was shown in the process with low void content, and Young's modulus tended to decrease as the resin content increased. In the bagging process, the subsidiary material controlled the flow of resin and air, and caused a difference in microstructure, affecting the change of mechanical properties.
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