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Probe cards mounted with vapor-liquid-solid (VLS) grown silicon whiskers were fabricated. The 'mesa method' in which VLS whiskers are grown on silicon mesas topped with gold hats, is successfully implemented which permits the accurate positioning of the VLS whiskers. The VLS whisker grows vertically to over 2000 microns in length and a diameter of 10-100 microns is produced. The metal-plated whisker has sufficient compliance with overdrive capability of up to 400 microns to compensate for the prober error and the possible irregularity of the wafer surface which maintains reliable contact.

The Waikite Hot Springs emit waters (most >90 [degrees] C) with a pH of 7.2-8.9, high Si[O.sub.2] (150-170mg [l.sup.-1]) concentrations, but low Ca ( Keywords: New Zealand, hot springs, calcite, crystal growth.

The evolution of the spherulitic morphology, commonly encountered during the solidification of semicrystalline materials, is modeled by taking into account the transport of the solute (the noncrystallizing species) and the crystallization kinetics. In this paper, a microscopic cell model is presented that incorporates the influence of these phenomena. The growth of the spherulite in the cell is represented by defining three concentric zones within the unit cell: a liquid zone, a dendritic zone, and a solid zone. The governing equations that describe the process are solved simultaneously with an integral method and a time-stepping scheme to obtain a description of the growth of a spherulite within the cell. Five dimensionless parameters are identified that affect the cooling profile and the microstructure. Also, the concentration profiles of the noncrystallizing species, the cooling history of the spherulite, and the evolution of the grain envelope and the dendritic zone are calculated during the solidification process. These results are obtained for boundary conditions of prescribed heat flow, prescribed cooling rate, and isothermal crystallization. The development of a significant interdendritic region is observed under prescribed heat flow, along with the rise in temperature associated with the self-heating of the polymer due to the latent heat. No interdendritic region developed with the prescribed cooling rate, and a much smaller one appeared under isothermal conditions. The solid fraction, in the last case, also reached a plateau below unity due to the choice of cooling conditions. These results are consistent with experimental observations., INTRODUCTION An accurate prediction of microstructure formation in semicrystalline polymers is of prime importance for parts made through injection molding, fiber spinning, or extrusion. The microstructure of the solidified polymer [...]

The salt impurities present in model lactose solutions and whey ultrafiltration permeate solutions influence the lactose crystal growth and solubility. The incorporation of LiCl in the model solution leads to a maximum rise in growth rate and a maximum fall in lactose solubility. K2HPO4 has an opposite effect on the growth rate and solubility in a model solution. Compared to the pure lactose solution, crystal growth rate is low and lactose solubility is high in whey ultrafiltration permeate solutions.

The occurrence of sector zoning in minerals of regional metamorphic or low-temperature intrusive origin implies that rapid growth is not required for the development of this particular form of homogeneous disequilibrium. It is shown here that sector zoning can be a natural consequence simply of slow lattice diffusion. Given anisotropic surface enrichrnent coupled with the low diffusivities typical of highly charged elements in refractory accessory minerals such as zircon and titanite, sector zoning can arise even in cases of growth rates as low as a few micrometers per million years. According to the proposed model, the development of sector zoning depends upon the competition between growth rate (V) and lattice diffusion ([D.sub.i]) within the near-surface layer (1), such that above a critical value of Vl/[D.sub.i] (~0.5-3), sector zoning is unavoidable in crystals that exhibit selective enrichment on some growth surfaces. Known diffusivities of rare earth elements in Zircon and titanite lead to the expectation of sector zoning in these minerals with respect to REEs for reasonable geologic growth rates. Even in the case of clinopyroxene, diffusion of REEs and high field-strength elements may be slow enough to contribute to the development of sector zoning in laboratory-grown crystals.