On cosmic-ray production efficiency at supernova remnant shocks propagating into realistic diffuse interstellar medium

Using three-dimensional magnetohydrodynamics simulations, we show that the efficiency of cosmic-ray (CR) production at supernova remnants (SNRs) is over-predicted if it could be estimated based on proper motion measurements of H$\alpha$ filaments in combination with shock-jump conditions. Density fluctuations of upstream medium make shock waves rippled and oblique almost everywhere. The kinetic energy of the shock wave is transferred into that of downstream turbulence as well as thermal energy which is related to the shock velocity component normal to the shock surface. Our synthetic observation shows that the CR acceleration efficiency as estimated from a lower downstream plasma temperature, is overestimated by 10-40%, because rippled shock does not immediately dissipate all upstream kinetic energy.Comment: 7 pages, 3 figures, 1 table, accepted for publication in ApJ; the paper with full resolution images is http://www.phys.aoyama.ac.jp/~ryo/papers/shimoda2015.pd

Effects of Growth Rates and Cooling Rates on Defect Generation in Melt-Grown Copper Crystals(Physics)

Single crystals of zone-refined Cu were grown from the melt at growth rates ranging from 0.1 to 29.0 mm/min and with cooling rates of the crystal after growth varying from 0.24 to 45℃/min. It was found that the growth rate had a very important effect on the generation of dislocations and their arrays, but the cooling rate of the crystal after growth had an important effect only when the crystal had been solidified at a rate of 0.1 mm/min

The reaction of nitrile with α-hydrogens under high pressure I : dimerization and trimerization of malononitrile

The effects of pressure on the reaction of malononitrile have been studied in water, methanol, ethanol, iso-propanol, dioxane, and so on in the temperature range of 323 to 343 K up to 8000 kg cm^-2. The reaction produced a dimer and two trimers only at high pressure. The dimer was identified as 1, 1, 3-tricyano-2-amino-1-propene and the trimers as 2, 4-diamino-3, 5-dicyano-6-cyanomethylpyridine, and ammonium 1, 1, 3, 3-tetracyano-2-cyanomethylpropenide, which are, respectively, the "Trimer 1" and "Trimer 2" reported by Schenck and Finken. The "Trimer 3" was not yielded.1. 3, 5-Tricyanomethyl-s-triazine was not produced in the present reaction either. The polar solvents and the addition of triethylamine increased the reaction rate remarkably. The formation of the dimer is autocatalytic and its mechanism is found to be a Thorpe-type reaction

Nitrogenase Fe protein-like Fe–S cluster is conserved in L-protein (BchL) of dark-operative protochlorophyllide reductase from Rhodobacter capsulatus

AbstractDark-operative protochlorophyllide reductase (DPOR) in bacteriochlorophyll biosynthesis is a nitrogenase-like enzyme consisting of L-protein (BchL-dimer) as a reductase component and NB-protein (BchN–BchB-heterotetramer) as a catalytic component. Metallocenters of DPOR have not been identified. Here we report that L-protein has an oxygen-sensitive [4Fe–4S] cluster similar to nitrogenase Fe protein. Purified L-protein from Rhodobacter capsulatus showed absorption spectra and an electron paramagnetic resonance signal indicative of a [4Fe–4S] cluster. The activity quickly disappeared upon exposure to air with a half-life of 20s. These results suggest that the electron transfer mechanism is conserved in nitrogenase Fe protein and DPOR L-protein

Analysis of the A-C Voltage Control Circuit with ParallelConnection of SCR and Reactor

The a-c voltage control circuit, composed of parallel connection of a SCR and a reactor, gives the similar performance as the control circuit of a back to back SCR pair. However, the control characteristics of this circuit is affected by magnetizing characteristics of reactor. In this paper, the circuit with the resistive load has been analyzed by using the approximated models of hysteresis loop of core materials, where the SCR's forward voltage drop is taken into account. The results of the analysis have revealed the facts as follows, I) The control characteristics of the a-c voltage in average value is independent on the magnetizing characteristics of reactors except in the vicinity of minimum output point. But, in effective value, it is not valid. 2) A SCR's forward voltage drop results in the reduction of not only SCR's current but also reactor's current. 3) The a-c output current does not include the d-c component, if the winding resistance of the reactor is negligible

Visual completion of partly occluded grating in infants under 1 month of age

AbstractFour groups of eight infants (3 weeks of age on average) were each habituated to one of four displays consisting of a grating of either low (0.4 cpd) or high (1.2 cpd) spatial frequency, whose central portion was covered up with a horizontal occluder which was either narrow (1.33°) or broad (4.17°). These habituation displays are referred to as LN (low spatial frequency grating and narrow occluder), LB (low and broad), HN (high and narrow), and HB (high and broad) displays. Posthabituation-test displays consisted of a complete grating (CG) of the same frequency as the habituated grating along with a separate grating (SG) whose central portion was replaced with a black gap of the same height as the occluder in the habituation displays. Infants habituated to the LN display looked significantly longer at the SG than the CG display during posthabituation-test trials. Infants habituated to the LB and HN displays looked at the CG and SG displays, almost equally. In contrast, infants habituated to the HB display looked longer at the CG than the SG display. These results show that infants under 1 month of age can perceive the continuation of the grating behind the occluder, and that their visual completion on habituation displays can be evoked according to the interaction between the spatial frequency of the grating and the occluder height