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Insulation coating is often applied to time domain reflectometry (TDR) soil moisture sensors to reduce the conduction loss of energy. However, because of low dielectric constants of common plastic insulation materials, sensitivity is reduced, and the measurements are strongly dependent on coating thickness. Analytical studies clearly showed that these unwanted features could be mitigated if a high dielectric material is used for coating. An epoxy‐ceramic nanocomposite was selected as a high dielectric insulation material because of its high dielectric constant and high adhesion. Experimental work using this composite indicated that the material has the potential to be used as a high dielectric coating for TDR soil moisture probes. On the basis of the results of these analytical and experimental studies a framework for designing an improved epoxy‐ceramic composite for coating TDR soil moisture sensors is suggested.

The modified embedded atom method (MEAM) was employed in conjunction with molecular dynamics (MD) simulations to investigate whether a physical mixture of nano-Sn and nano-Ag particles at a prescribed ratio would achieve the same intermixing as a nano-Sn/Ag alloy. A Sn sphere and a Ag sphere both with a diameter of 4 nm were prepared by cutting the perfect bulk lattice structure. After energy minimization and structural relaxation, the two spheres were placed next to each other with a gap of 3 Å. The simulation was then performed at 500 K for 3 ns. Simulation results showed that the nano-Ag sphere still maintained its crystalline structure and no significant diffusion between Sn and Ag was observed. Further simulations were performed at 800 K, 850 K, 900 K and 1000 K, respectively, in order to obtain the activation energy of interdiffusion between An and Sn. It was then predicted that 118 ns was required for Sn and Ag to mix with each other at 500 K. The results implied that a physical mixture of nano-Sn and nano-Ag particles may satisfy the requirements of lead free solder for low temperature (∼500 K) reflow applications.

In the last few years, flip chip technology has been increasingly employed in a variety of applications in the microelectronics industry. Comparing to conventional wirebonding technology, flip chip provides lower profile, faster signal transfer, and higher VO

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