A Fully Integrated Thin‐Film Inductor and Its Application to a DC‐DC Converter

This paper presents a simple process to integrate thin‐film inductors with a bottom NiFe magnetic core. NiFe thin films with a thickness of 2 to 3 μm were deposited by sputtering. A polyimide buffer layer and shadow mask were used to relax the stress of the NiFe films. The fabricated double spiral thin‐film inductor showed an inductance of 0.49 μH and a Q factor of 4.8 at 8 MHz. The DC‐DC converter with the monolithically integrated thin‐film inductor showed comparable performances to those with sandwiched magnetic layers. We simplified the integration process by eliminating the planarization process for the top magnetic core. The efficiency of the DC‐DC converter with the monolithic thin‐film inductor was 72% when the input voltage and output voltage were 3.5 V and 6 V, respectively, at an operating frequency of 8 MHz.     

Demagnetization due to inverse magnetostriction effects inlongitudinal thin film media

Unpredictable mechanical stresses that occur during the operation of hard disk drives can degrade the recorded signal. On the basis of a micromagnetic analysis and the calculated stress field during head-disk impact, inverse magnetostriction effects in longitudinal recording thin film media are considered and demagnetization due to head-disk impact is simulated numerically. Thin film media are modeled as planar hexagonal arrays of hexagonally shaped grains. The computation uses the conjugate gradient algorithm to minimize the variation of the total energy. In particular, the effect of the stress on the relaxation process is investigated. Also the change in the remanent magnetization due to repetitive head-disk impacts is calculated. We obtained results indicating that the effect of the impact stress during dynamic loading is not so significant as to cause data loss during operation for the longitudinal thin film media     

Multicast‐aware power allocation in multiple spot‐beam satellite communication systems

In this paper, we address the problem of user heterogeneity in satellite multicast from the perspective of resource allocation in a multiple spot‐beam satellite system that supports both unicast and multicast flows. Satellite communication systems, with their wide‐area coverage and direct access to large number of users, clearly have an inherent advantage in supporting multicast applications. In order to remain competitive against other broadband technologies, however, next generation satellite systems will be required to support both unicast and multicast flows and offer optimal sharing of system resources between these flows. We show that user heterogeneity across spot‐beam queues may result in lower allocated session rates for active flows, and be perceived as unsatisfactory by potential users when both unicast and multicast flows are active in the system. We propose an optimization‐based approach that allocates resources with the goal of smoothing user heterogeneity, and show that resulting session rates are higher on the average for both unicast and multicast flows. This is achieved through the re‐distribution of system power among spot‐beam queues, by taking into account the load on the queues and the channel states. We conclude that it is possible to increase the average session rates of multicast flows by 25–100%, and the rates of unicast flows by 15–40% compared to the pre‐optimization levels. Copyright © 2006 John Wiley & Sons, Ltd.     

In Vitro Delivery of Fluocinolone Acetonide in FAPG Base

The effects of oleic acid and lauric acid in a mixture of fatty alcohol and propylene glycol (FAPG base) on the percutaneous absorption of fluocinolone acetonide (FA) were investigated by using nude mouse skin and synthetic membrane in vitro. me mixture of 0.9% sodium chloride and methanol (91) was used as the receptor phase for the diffusion study. The concentration of FA in the receptor phase was determined by HPLC. fie optimal formulation of the FAPG base was obtained with the addition of 5% lauric acid     

Controlled hydrothermal growth of multi-length-scale ZnO nanowires using liquid masking layers

In this study, we demonstrate a method for creating multi-length-scale ZnO nanowires in a controllable manner on diverse planar and curvilinear substrates by introducing immiscible liquid masking layers (LMLs) above and beneath a nutrient solution used in hydrothermal growth. The confinement of volatile reactants by the LMLs stabilizes the pH, which is an important parameter in determining the shape of the nanowires, to enable growth in a stable manner. The conformal wettability of the LMLs provides freedom in the choice of target substrates and allows for the possibility of mounting spatially moving stages without the use of a specially designed solid lid. Selective growth within the growth zone defined by the LMLs in a dynamic- and/or static-mode can create various types of ZnO nanowires with gradual or terraced length profiles in two- or three-dimensional geometries. For a device application, we developed cylindrical photodetectors with the configuration of Cr/ZnO seed/ZnO nanowires/poly(3-hexylthiophene-2,5-diyl)/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) to show the ability to spatially modulate the photo-sensitivity by controlled hydrothermal growth of diverse length scales of ZnO nanowires using the LML method.