Patterned metal films have been shown to possess unique optical properties resulting from the excitation of surface plasmon polaritons at the patterned metal surface. Here we demonstrate spectrally selective thermal emission from patterned steel substrates. The materials and processes used in this work were chosen for their potential scalability to large-area and low cost production of metal films with distinct and designable thermal signatures. The samples studied were characterized by reflection and emission spectroscopy, and a factor of 2.6 emission enhancement is demonstrated for the design wavelength. These results are compared to numerical simulations.

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Viscoplastic finite-element (FE) simulation is used to predict board-level solder joint reliability of ball grid array (BGA) packages under accelerated temperature cycling (ATC) conditions. The model is first validated against archived ATC data, then parametric studies are conducted to examine the model's sensitivity to changes in design factors and thenno-mechanical material properties. The use of the program Surface Evolver to predict BGA solder joint shape and profile is briefly discussed.

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Methamphetamine (METH) is a highly addictive psychostimulant that has been shown to produce neurotoxicity. Methamphetamine increases the release of dopamine by reversing the direction of monoamine transporter proteins, leading to the formation of reactive oxygen species in the brain. In this study, we examined the effect of METH on DNA damage in vivo using the single cell gel electrophoresis assay (comet assay) under two different conditions. Rats treated with multiple doses of METH (10 mg/kg × 4) showed significant levels of DNA damage in the nucleus accumbens and striatum, both dopamine-rich areas. In contrast, a single dose of METH did not lead to significant levels of DNA damage in any of the dopamine-rich brain regions that were tested. Overall, the results of our study demonstrate that METH produces greater oxidative DNA damage in brain areas that receive greater dopamine innervation.

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There are continuous efforts in the electronics industry to reduce electronic package size. The main force pushing for smaller package size is the desire by original equipment manufacturers to reduce their mother board size and thereby their own costs. Reducing the size of electronic packages can be achieved by a variety of means and for ball grid array (BGA) packages an effective method is to decrease the pitch between the individual balls. Reducing the pitch between balls decreases the ball size and therefore the standoff between the packages and motherboards is reduced. The reduced standoff has the negative effect of reducing board-level reliability. An experiment to understand board-level reliability improvement by underfilling the BGA will be presented for several finepitch plastic BGA types (fleXBGA and MAP (mold array process)). Four different (snap-cure) underfill epoxies with varied coefficients of thermal expansion and elastic moduli were used so that the preferred set of epoxy properties could be determined. A full factorial numerical experiment was used to identify the optimum combination of CTE and elastic modulus. Results indicate that a signficant increase in boardlevel reliability can be achieved by underfilling the BGA. I. IntroductionMany end customer have a continuous desire to reduce the size of their final assembled boards. This is coupled with end customer needs to constantly squeeze costs out of their final product. A simple method for accomplishing both is for an end customer to push their own suppliers in supplying smaller packages. The smaller package takes less materials and therefore nominally might cost less. With a smaller package, the end customer can begin to shrink the final board design.One consequence of pushing suppliers into smaller packages is that the board-level reliability can decrease. For a BGA type package, a primary driver for board-level reliability is the standoff height [1], the distance between the board and the package. As this decreases, the life of the solder-joint connecting the board and package can decrease.Past efforts have shown that underfilling the BGA for ceramic substrate packages can significantly increase the board-level reliability for these parts [2,3]. Using the knowledge from [3] the present board-level reliability experiment and numerical modeling of underfilled plastic BGA packages were started.