23,901 research outputs found
The lipid composition and its alteration during the growth stage in pathogenic fungus, epidermophyton floccosum
Qualitative and quantitative changes of lipid components during the growth stages were studied in E. floccosum. The acyl group components of total lipids of Trichophyton rubrum and Microsporum cookei were also examined. The lipids of E. floccosum amounted to approximately 4% of the dry cell weight. Neutral lipids mainly consisted of triglycerides and sterols, and major polar lipids were phosphatidylcholine, phosphatidylethanolamine, and an unknown lipid X. The fatty acids in tryglycerides and phospholipids were palmitic, palmitoleic, stearic, oleic, and linoleic acids. The unknown polar lipid X which appeared between phosphatidylethanolamine and cardiolipin on thin layer chromatography plates contained no phosphorus. There was no significant change in the fatty acid components of E. floccosum and T. rubrum during the cell growth, whereas profound changes occurred in M. cookei. The sterol components of E. floccosum showed striking changes depending on the growth stage
FE analysis on tube hydroforming of small diametr ZM21 magnesium alloy tube
Tube hydroforming (THF) is one of the plasticity processing methods. Tubular parts, for instance automotive components are expanded by forces such as internal pressure and axial compression in order to deform an objective shape. THF has less restriction on shape and size of workpieces owing to adopting the liquid tool. The demand of a small diameter magnesium alloy tubular parts have been increased for applying small medical and electronic devices. In this study, it was investigated that influence of process conditions such as processing temperature, internal pressure and axial feeding amount on formability of small diameter ZM21 magnesium alloy tube with outer diameter of 2.0mm and thickness of 0.20mm. Furthermore, the processing conditions for improving the formability of material in THF were examined. For prior evaluation of deformation characteristics in the warm THF of small diameter ZM21 magnesium alloy tube, a finite element (FE) simulation was conducted. The FE method (FEM) code was used LS-DYNA 3D for analysis of the FE model of the tube and the dies. The material characteristics were obtained by tensile test and fracture test. From FE analysis results, it was elucidated that effect of the processing temperature, the variable internal pressure and the axial feeding amount on deformation behavior. The formability of ZM21 magnesium alloy tube was improved by processing at 250 C. The difference of deformation characteristic between FE results and experimental results was compared. As the results, the processing condition which could improve the formability of ZM21 tube was clarified using this FE model. The effect of adding the straightening stage in the loading path after the preform on formability was investigated. The thinning of the wall thickness of the tube was inhibited by calibration after the axial feeding
Nucleon Spin in QCD: Old Crisis and New Resolution
We discuss the shortfalls of existing resolutions of the long-standing gauge
invariance problem of the canonical decomposition of the nucleon spin to the
spin and angular momentum of quarks and gluons. We provide two logically
flawless expressions of nucleon spin which have different physical meanings,
using the gauge independent Abelian decomposition. The first one is based on
the assumption that all gluons (binding and valence gluons) contribute to the
nucleon spin, but the second one is based on the assumption that only the
binding gluons (and the quarks) contribute to it. We propose the second
expression to be the physically correct one
Fe-doping-induced evolution of charge-orbital ordering in a bicritical-state manganite
Impurity effects on the stability of a ferromagnetic metallic state in a
bicritical-state manganite, (La0.7Pr0.3)0.65Ca0.35MnO3, on the verge of
metal-insulator transition have been investigated by substituting a variety of
transition-metal atoms for Mn ones. Among them, Fe doping exhibits the
exceptional ability to dramatically decrease the ferromagnetic transition
temperature. Systematic studies on the magnetotransport properties and x-ray
diffraction for the Fe-doped crystals have revealed that charge-orbital
ordering evolves down to low temperatures, which strongly suppresses the
ferromagnetic metallic state. The observed glassy magnetic and transport
properties as well as diffuse phase transition can be attributed to the
phase-separated state where short-range charge-orbital-ordered clusters are
embedded in the ferromagnetic metallic matrix. Such a behavior in the Fe-doped
manganites form a marked contrast to the Cr-doping effects on
charge-orbital-ordered manganites known as impurity-induced collapse of
charge-orbital ordering.Comment: 8 pages, 7 figure
A mobile antineutrino detector with plastic scintillators
We propose a new type segmented antineutrino detector made of plastic
scintillators for the nuclear safeguard application. A small prototype was
built and tested to measure background events. A satisfactory unmanned field
operation of the detector system was demonstrated. Besides, a detailed Monte
Carlo simulation code was developed to estimate the antineutrino detection
efficiency of the detector.Comment: 23 pages, 11 figures; accepted for publication in Nuclear Instruments
and Methods in Physics Research
Generalized McKay quivers of rank three
For each finite subgroup G of SL(n, C), we introduce the generalized Cartan
matrix C_{G} in view of McKay correspondence from the fusion rule of its
natural representation. Using group theory, we show that the generalized Cartan
matrices have similar favorable properties such as positive semi-definiteness
as in the classical case of affine Cartan matrices (the case of SL(2,C)). The
complete McKay quivers for SL(3,C) are explicitly described and classified
based on representation theory
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