Performance and Safety Characteristics of Lithium-molybdenum Disulfide Cells

The lithium-molybdenum disulfide system offers attractive characteristics including high rate capability, successful operation up to 75 C, a very low self-discharge rate, a good cycle life and safety characteristics which compare favorably to those of other lithium cells. Moreover, the materials and manufacturing costs for the system is effectively controlled, so the cells should ultimately be competitive with currently marketed rechargeable cells

A numerical method to solve the Boltzmann equation for a spin valve

We present a numerical algorithm to solve the Boltzmann equation for the electron distribution function in magnetic multilayer heterostructures with non-collinear magnetizations. The solution is based on a scattering matrix formalism for layers that are translationally invariant in plane so that properties only vary perpendicular to the planes. Physical quantities like spin density, spin current, and spin-transfer torque are calculated directly from the distribution function. We illustrate our solution method with a systematic study of the spin-transfer torque in a spin valve as a function of its geometry. The results agree with a hybrid circuit theory developed by Slonczewski for geometries typical of those measured experimentally.Comment: 13 pages, 8 figure

Peculiar long-range superexchange in Cu2A2O7 (A = P, As, V) as a key element of the microscopic magnetic model

A microscopic magnetic model for alpha-Cu2P2O7 is evaluated in a combined theoretical and experimental study. Despite a dominant intradimer coupling J1, sizable interdimer couplings enforce long-range magnetic ordering at T_N=27 K. The spin model for alpha-Cu2P2O7 is compared to the models of the isostructural beta-Cu2V2O7 and alpha-Cu2As2O7 systems. As a surprise, coupled dimers in alpha-Cu2P2O7 and alternating chains in alpha-Cu2As2O7 contrast with a honeycomb lattice in beta-Cu2V2O7. We find that the qualitative difference in the coupling regime of these isostructural compounds is governed by the nature of AO4 side groups: d-elements (A = V) hybridize with nearby O atoms forming a Cu-O-A-O-Cu superexchange path, while for p-elements (A = P, As) the superexchange is realized via O-O edges of the tetrahedron. Implications for a broad range of systems are discussed.Comment: 8 pages, 5 figures, 1 table; discussion extende

PCPro a Novel Technology for Rapid Prototyping and Rapid Manufacturing

PCPro stands for Precise Cast Prototyping, which is a combination of casting technologies and milling. This method was developed at Fraunhofer IWS in Dresden, Germany. It is patented in Germany [1] and is applied in the USA under US 10/794,936. The main goal for this development was to shorten the process chain for making plastic prototypes accompanied by higher quality. The casting technology was integrated in a machining center in order to enable a high degree of automation and to avoid an external casting system. This means that Rapid Manufacturing can be easily implemented using such an automated combination of casting and machining. This article describes the PCPro method by means of the fabrication of sample parts. The advantages and the limitations in comparison to common Rapid Prototyping and Rapid Manufacturing process chains will be discussed. In addition, the manufacturing of a prototype machine is presented.Mechanical Engineerin

Macrospin Models of Spin Transfer Dynamics

The current-induced magnetization dynamics of a spin valve are studied using a macrospin (single domain) approximation and numerical solutions of a generalized Landau-Lifshitz-Gilbert equation. For the purpose of quantitative comparison with experiment [Kiselev {\it et al.} Nature {\bf 425}, 380 (2003)], we calculate the resistance and microwave power as a function of current and external field including the effects of anisotropies, damping, spin-transfer torque, thermal fluctuations, spin-pumping, and incomplete absorption of transverse spin current. While many features of experiment appear in the simulations, there are two significant discrepancies: the current dependence of the precession frequency and the presence/absence of a microwave quiet magnetic phase with a distinct magnetoresistance signature. Comparison is made with micromagnetic simulations designed to model the same experiment.Comment: 14 pages, 14 figures. Email [email protected] for a pdf with higher quality figure

Phenolic cutter for machining foam insulation

Pre-pregged fiber glass is an efficient abrasive for machining polystyrene and polyurethane foams. It bonds easily to any cutter base made of aluminum, steel, or phenolic, is inexpensive, and is readily available

Recent Advances in Human Genetics - Paper Presented at the Fifty-Fifth Annual Meeting

Advances in human genetics are taking place on several fronts; and despite the diversity of attacks on the problems involved, the author of this paper will limit himself to a few areas in which he and his students have either done some research or have a special interest. Every year some advances are being made in our knowledge of the inheritance of physical traits and an attempt will be made to briefly indicate some of the achievements and problems encountered in this field of study. The writer has been making a number of studies of the inheritance of physical traits