Thermally activated reversal in exchange-coupled structures

In this paper, we study the thermally activated reversal of IrMn/CoFe exchange-coupled structures using Lorentz microscopy and magnetometry. An asymmetry and a training effect were found on the hysteresis loops both with and without holding the film at negative saturation of the ferromagnetic layer. Holding the film at negative saturation results in the hysteresis loop shifting toward zero field. We believe that, in this system, two energy barrier distributions with different time constants coexist. The large-time-constant thermally activated reversal of the antiferromagnetic layer contributes to a increasing shift of the entire hysteresis loop toward zero field with increased period of time spent at negative saturation of the ferromagnetic layer. The small-time-constant thermal activation contributes to asymmetry in the magnetization reversal and training effects

Enzymuria in Streptozotocin-Diabetic Rats

Peer Reviewe

3D Printing Multi-Functionality: Embedded RF Antennas and Components

Significant research and press has recently focused on the fabrication freedom of Additive Manufacturing (AM) to create both conceptual models and final end-use products. This flexibility allows design modifications to be immediately reflected in 3D printed structures, creating new paradigms within the manufacturing process. 3D printed products will inevitably be fabricated locally, with unit-level customization, optimized to unique mission requirements. However, for the technology to be universally adopted, the processes must be enhanced to incorporate additional technologies; such as electronics, actuation, and electromagnetics. Recently, a novel 3D printing platform, Multi3D manufacturing, was funded by the presidential initiative for revitalizing manufacturing in the USA using 3D printing (America Makes - also known as the National Additive Manufacturing Innovation Institute). The Multi3D system specifically targets 3D printed electronics in arbitrary form; and building upon the potential of this system, this paper describes RF antennas and components fabricated through the integration of material extrusion 3D printing with embedded wire, mesh, and RF elements

Trailblazer: Proof of Concept CubeSat Mission for SPA-1

The Space Plug-and-play Architecture (SPA) concept of rapid satellite development has progressed exponentially over the past several years. The team at the Configurable Space Microsystems Innovations and Applications Center (COSMIAC) in conjunction with the Space Dynamics Laboratory (SDL) and the Air Force Research Laboratory have trained over 500 individuals on this rapid bus architecture related to satellite development. This paper will outline the first CubeSat satellite proof of concept flight for a SPA only spacecraft. The Trailblazer mission is designed to fly a 1U CubeSat that is based entirely on a SPA bus implementation. Trailblazer will consist of Commercial Off The Shelf (COTS) parts converted to be SPA compliant. This allows not only a demonstration of the bus reliability in a space environment, but also the ease in converting existing components to be SPA compliant. With the dimensional constraints and power budget of Trailblazer, we have elected to use the SPA-1 standard. SPA-1 is the most recent addition to the AFRL SPA family. The SPA-1 data transfer protocol is based on 400 kbit/s I2C making it the lowest power, and lowest bandwidth option for SPA. Given the power constraints of typical satellite architecture, it is generally advantageous to interface devices/modules which do not require high data transfer rates to a SPA network via the SPA-1 Applique Sensor Interface Module (ASIM). This ASIM is logic that enables SPA Plug-and-Play for hardware components. It contains all the information needed for the system to automatically discover and automatically configure the hardware component. SPA-1 ASIMs can be any microcontroller that supports I2C and has enough memory to contain the needed logic. This allows the standard to remain open to a variety of dynamic implementations. The Trailblazer mission is being launched under the National Aeronautics and Space Administration (NASA) Educational Launch of Nanosatellite (ELaNA) program. This NASA program is designed to provide affordable access to space through collaborative efforts with academic institutions. The ELaNA program provides manifesting and launch of CubeSats for $30,000 per 1U module. The proposed orbit is 325 km with an inclination of 51 degrees for a launch in 2011

Exchange Anisotropy in Epitaxial and Polycrystalline NiO/NiFe Bilayers

(001) oriented NiO/NiFe bilayers were grown on single crystal MgO (001) substrates by ion beam sputtering in order to determine the effect that the crystalline orientation of the NiO antiferromagnetic layer has on the magnetization curve of the NiFe ferromagnetic layer. Simple models predict no exchange anisotropy for the (001)-oriented surface, which in its bulk termination is magnetically compensated. Nonetheless exchange anisotropy is present in the epitaxial films, although it is approximately half as large as in polycrystalline films that were grown simultaneously. Experiments show that differences in exchange field and coercivity between polycrystalline and epitaxial NiFe/NiO bilayers couples arise due to variations in induced surface anisotropy and not from differences in the degree of compensation of the terminating NiO plane. Implications of these observations for models of induced exchange anisotropy in NiO/NiFe bilayer couples will be discussed.Comment: 23 pages in RevTex format, submitted to Phys Rev B

The metabolism of certain herbicides by plants : a key factor in their biological activity

Published March 1961. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo