CoB/Ni-Based Multilayer Nanowire with High-Speed Domain Wall Motion under Low Current Control

The spin-transfer torque motion of magnetic domain walls (DWs) in a CoB/Ni-based nanowire driven by a low current density of (1.12\pm0.8)\times10^{11} A m^{-2} has been observed indirectly by magnetotransport measurements. A high DW velocity of 85\pm4 m/s at zero field was measured at the threshold current density. Upon increasing the current density to 2.6\times10^{11} A m^{-2}, the DW velocity increases to 197\pm16 m/s before decreasing quickly in the high-current-density regime attributed to nonadiabatic spin-transfer torque at a low damping factor and weak pinning. The addition of B atoms to the Co layers decreased the magnitude of saturation magnetization, Gilbert damping factor, and density of pinning sites, making the CoB/Ni multilayer nanowire favorable for practical applications.Comment: 4 pages, 5 figures; PACS: 72.25.Ba, 75.60.Ch, 75.70.Cn, 75.75.Cd, 75.76.+j, 75.78.F

Wind Electronic Generator NU-101 Driven by Axial-Flow Air-Turbine with Stator

"Generators driven by axial-flow air-turbine with stator are relatively small in size and can be adapted to withstand violent blizzards. They are suitable for antarctic use, especially as energy sources for unmanned observation units. An analysis is given of the performance of an axial-flow air-turbine comprising a stator having stationary blades and a rotor having moving blades. Changes in the velocity and thermodynamic properties of the air flow in passing through the turbine are discussed quantitatively, and the expression for the output power and efficiencies of the turbine are given. It is shown that the output attains its maximum when the axial velocity of the air flow in the turbine is 1/√ of the wind velocity. The method of evaluation of the maximum annual wind energy available is discussed. The design of turbine blades is described: the constant nozzle angle design is adopted for the stationary blades, and the axially leaving velocity design for the moving blades. The starting torque, the starting wind velocity, and the off- design performance of the wind air-turbine are also studied. The performance of an air-turbine with stator is compared theoretically to that of an ordinary wind air-turbine without stator, and it is verified the maximum output power allowable for the former will be about 140% of the latter at a lower rotational speed than the latter, which will be about 70% thereof. A wind electric generator designated NU-101 which has been designed on the basis of the discussion outlined above is described. This comprises an axial-flow air-turbine, 1.2m in diameter, whose maximum rotational velocityis 300 RPM, and a 2 kW, 100V, AC generator. In 1972, this generator wasshipped to Syowa Station, Antarctica, by the 14th Japanese Antarctic ResearchExpedition (JARE). The results of some test runs in Tokyo in 1972 and atSyowa Station in 1973 are given.

Weight Distributions of Multi-Edge type LDPC Codes

The multi-edge type LDPC codes, introduced by Richardson and Urbanke, present the general class of structured LDPC codes. In this paper, we derive the average weight distributions of the multi-edge type LDPC code ensembles. Furthermore, we investigate the asymptotic exponential growth rate of the average weight distributions and investigate the connection to the stability condition of the density evolution.Comment: To appear in IEICE Trans. Fundamentals, vol.E93-A, no.11 November 201

Energy saving at Syowa and Mizuho Stations

"At Syowa Station, which was opened in 1957, two diesel electric generators were installed, one of which was always operated as the main energy source. The electric capacity of each generator has been increased from 20 kVA to 110 kVA in accordance with the expansion of the station. In order to save fuel consumption, the authors have developed some waste heat recovery systems of the diesel engines. By fully utilizing the waste heat of diesel engines, i.e., their exhaust-gas energy and coolant energy, cold and hot water was made from ice or snow even in winter. The hot and cold water was supplied to the living quarters through insulated water pipes. The hot water was also supplied for bathing and heating of apartments of the buildings. At Mizuho Station, which was opened in 1970, a system for recovering coolant heat of a diesel electric generator was installed. The cold and hot water is made by the similar system. The hot water is supplied to a bathtub and to a fan-coil unit in a trench living room. The heating by utilizing the waste coolant can ensure the safety of the personnel living in the trench room against fire, contamination by CO, CO_2 and lack of oxygen. In this report, the technical problems and experiences on waste heat recovering, especially on exhaust-gas heat exchangers are described.

Clinical reasoning in canine spinal disease: what combination of clinical information is useful?

Spinal disease in dogs is commonly encountered in veterinary practice. Numerous diseases may cause similar clinical signs and presenting histories. The study objective was to use statistical models to identify combinations of discrete parameters from the patient signalment, history and neurological examination that could suggest the most likely diagnoses with statistical significance. A retrospective study of 500 dogs referred to the Queen Mother Hospital for Animals before June 2012 for the investigation of spinal disease was performed. Details regarding signalment, history, physical and neurological examinations, neuroanatomical localisation and imaging data were obtained. Univariate analyses of variables (breed, age, weight, onset, deterioration, pain, asymmetry, neuroanatomical localisation) were performed, and variables were retained in a multivariate logistic regression model if P<0.05. Leading diagnoses were intervertebral disc extrusion (IVDE, n=149), intervertebral disc protrusion (n=149), ischaemic myelopathy (IM, n=48) and neoplasms (n=44). Multivariate logistic regression characterised IM and acute non-compressive nucleus pulposus extrusions as the only peracute onset, non-progressive, non-painful and asymmetrical T3-L3 myelopathies. IVDE was most commonly characterised as acute onset, often deteriorating, painful and largely symmetrical T3-L3 myelopathy. This study suggests that most spinal diseases cause distinctive combinations of presenting clinical parameters (signalment, onset, deterioration, pain, asymmetry, neuroanatomical localisation). Taking particular account of these parameters may aid decision making in a clinical setting

Stable ultrahigh-density magneto-optical recordings using introduced linear defects

The stability of data bits in magnetic recording media at ultrahigh densities is compromised by thermal `flips' -- magnetic spin reversals -- of nano-sized spin domains, which erase the stored information. Media that are magnetized perpendicular to the plane of the film, such as ultrathin cobalt films or multilayered structures, are more stable against thermal self-erasure than conventional memory devices. In this context, magneto-optical memories seem particularly promising for ultrahigh-density recording on portable disks, and bit densities of $\sim$100 Gbit inch$^{-2}$ have been demonstrated using recent advances in the bit writing and reading techniques. But the roughness and mobility of the magnetic domain walls prevents closer packing of the magnetic bits, and therefore presents a challenge to reaching even higher bit densities. Here we report that the strain imposed by a linear defect in a magnetic thin film can smooth rough domain walls over regions hundreds of micrometers in size, and halt their motion. A scaling analysis of this process, based on the generic physics of disorder-controlled elastic lines, points to a simple way by which magnetic media might be prepared that can store data at densities in excess of 1 Tbit inch$^{-2}$.Comment: 5 pages, 4 figures, see also an article in TRN News at http://www.trnmag.com/Stories/041801/Defects_boost_disc_capacity_041801.htm