Accelerated battery-life testing - A concept

Test program, employing empirical, statistical and physical methods, determines service life and failure probabilities of electrochemical cells and batteries, and is applicable to testing mechanical, electrical, and chemical devices. Data obtained aids long-term performance prediction of battery or cell

The effect of low-energy ion-implantation on the electrical transport properties of Si-SiO2 MOSFETs

Using silicon MOSFETs with thin (5nm) thermally grown SiO2 gate dielectrics, we characterize the density of electrically active traps at low-temperature after 16keV phosphorus ion-implantation through the oxide. We find that, after rapid thermal annealing at 1000oC for 5 seconds, each implanted P ion contributes an additional 0.08 plus/minus 0.03 electrically active traps, whilst no increase in the number of traps is seen for comparable silicon implants. This result shows that the additional traps are ionized P donors, and not damage due to the implantation process. We also find, using the room temperature threshold voltage shift, that the electrical activation of donors at an implant density of 2x10^12 cm^-2 is ~100%.Comment: 11 pages, 10 figure

A study of the magnesium content of plant material

The experiments with grass and clover at Boghall and ryegrass at Bush showed that: -1. the mineral content of different species of grass and clover varied considerably, the clovers tending to be higher in mineral content than the grasses.2. the mineral content of white clover was affected by the grass with which it was grown and the competition with the grass for the available nutrients, particularly in the case of phosphorus.3. the mineral content of both grasses and clover varied considerably from month to month, the nature of the variation depending on the frequency of cutting. In grasses cut monthly, the minerai content tended to increase towards the end of the season, while in uncut ryegrass, the mineral content decreased as the grass matured.4. treatment with "nitrochalk" increased the calcium and magnesium contents of grasses throughout the season, and increased the phosphorus content initially. The effect of treatment on the clover seemed to depend on the yield and leafiness of the grass with which it was grown and the consequent competition between the grass and clover.5. treatment with heavy dressings of MgSO4.7H2O increased he magnesium content of ryegrass throughout the season. . the uptake of minerals varied from species to species and from month to month throughout the season, the monthly variation generally following that of the yield. The uptake of minerals by clover was lower than that of the grasses /because of the lower yield of the clover. The total seasonal uptakes of calcium and of phosphorus were greater than the uptake of magnesium.7. treatment with "nitrochalk" increased the uptake of all three elements by both grass and clover.The mineral content of a sward will therefore depend on the botanical composition of the sward, the frequency of cutting, the time of year and tiffe fertiliser treatment. The experiments with mixed herbage grown for hay and for dried grass bore out these results and showed that: -1. the magnesium content of the herbage depended on the available magnesium in the soil.2. the mineral content of herbage decreased with advancing maturity.3. the effect of the fertilisers studied depended not only on the nature of the fertiliser but also on the mineral status of the soil to which it was applied and the existing cation: anion ratios.(a) magnesium sulphate raised the magnesium content of the herbage, particularly where the soil was low in available magnesium.(b) potassium sulphate depressed the magnesium and phsophorus contents of herbage and in some cases the calcium content also.(c) potassium -magnesium sulphate had little effect on the magnesium ani phosphorus contents of herbage, and was therefore more suitable for use where the soil was low in available magnesium.The experiments with turnips and kale showed that: - 1. the yield of dry matter and the uptake of minerals in the leaf was less than that of the roots in turnips and of the stem in kale. 2. the mineral content of the leaf was higher than that of the roots in turnips and of the stem in kale. 3. the magnesium content of turnip leaves depended on the available magnesium in the soil. 4. treatment with potassium -magnesium sulphate increased ¡the dry matter yield of turnip roots where the available soil magnesium was low, and increased the yield of magnesium content of kale leaves, and the uptake of magnesium by the leaves

Differential thermal analysis and solution growth of intermetallic compounds

To obtain single crystals by solution growth, an exposed primary solidification surface in the appropriate, but often unknown, equilibrium alloy phase diagram is required. Furthermore, an appropriate crucible material is needed, necessary to hold the molten alloy during growth, without being attacked by it. Recently, we have used the comparison of realistic simulations with experimental differential thermal analysis (DTA) curves to address both these problems. We have found: 1) complex DTA curves can be interpreted to determine an appropriate heat treatment and starting composition for solution growth, without having to determine the underlying phase diagrams in detail. 2) DTA can facilitate identification of appropriate crucible materials. DTA can thus be used to make the procedure to obtain single crystals of a desired phase by solution growth more efficient. We will use some of the systems for which we have recently obtained single-crystalline samples using the combination of DTA and solution growth as examples. These systems are TbAl, Pr$_7$Ni$_2$Si$_5$, and YMn$_4$Al$_8$.Comment: 17 pages, 8 figure

Electrically-detected magnetic resonance in ion-implanted Si:P nanostructures

We present the results of electrically-detected magnetic resonance (EDMR) experiments on silicon with ion-implanted phosphorus nanostructures, performed at 5 K. The devices consist of high-dose implanted metallic leads with a square gap, into which Phosphorus is implanted at a non-metallic dose corresponding to 10^17 cm^-3. By restricting this secondary implant to a 100 nm x 100 nm region, the EDMR signal from less than 100 donors is detected. This technique provides a pathway to the study of single donor spins in semiconductors, which is relevant to a number of proposals for quantum information processing.Comment: 9 pages, 3 figure

Language and art activities at primary level: the EE dimension

The inter-relationship of language and art with environmental education (EE) within the Primary Education Upgrading Prograrnne (PEUP) in Bophuthatswana is described and discussed

Diagnosing pregnancy in sheep : the \u27Scanopreg\u27

The Scanopreg , an ultrasonic machine for diagnosing pregnancy in sheep, is effective as early as eight to nine weeks of pregnancy, and could therefore be a useful management tool

Low-Temperature Rapid Synthesis and Superconductivity of Fe-Based Oxypnictide Superconductors

we were able to develop a novel method to synthesize Fe-based oxypnictide superconductors. By using LnAs and FeO as the starting materials and a ball-milling process prior to solid-state sintering, Tc as high as 50.7 K was obtained with the sample of Sm 0.85Nd0.15FeAsO0.85F0.15 prepared by sintering at temperatures as low as 1173 K for times as short as 20 min.Comment: 2 pages,2 figures, 1 tabl

Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making

A method of making a permanent magnet wherein 1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and 2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties