271 research outputs found
Characterization of high-fracture toughness K-fluorrichterite-fluorapatite glass ceramics
Stoichiometric K-fluorrichterite (Glass A) and the same composition with 2 mol% P2O5 added (Glass B) were prepared and then heat-treated isothermally from 550°1000°C with 50°C intervals. Samples were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The biaxial flexural strength and indentation fracture toughness of heat-treated glass specimens were also determined for both materials. XRD traces and TEM images showed similar phase evolution and fine microstructures for both systems at ≤950°C, with mica and diopside reacting with residual glass to form K-fluorrichterite as the temperature was increased from 650°C. However, in Glass B, fluorapatite was also present at >800°C. In contrast, coarser microstructures were observed at 1000°C, with larger K-fluorrichterite (20 μm) and enstatite (10 μm) crystals in Glasses A and B, respectively. The highest fracture toughness (2.69 ± 0.01 MPa·m(1/2)) and biaxial strength (242.6 ± 3.6 MPa) were recorded for Glass B heat-treated at 1000°C. This was attributed to the presence of enstatite coupled with an interlocked lath-like crystalline microstructure
QCD Pressure and the Trace Anomaly
Exact relations between the QCD thermal pressure and the trace anomaly are
derived. These are used, first, to prove the equivalence of the thermodynamic
and the hydrodynamic pressure in equilibrium in the presence of the trace
anomaly, closing a gap in previous arguments. Second, in the temporal axial
gauge a formula is derived which expresses the thermal pressure in terms of a
Dyson-resummed two-point function. This overcomes the infrared problems
encountered in the conventional perturbation-theory approach.Comment: 9 pages plain te
Beverage preparation from fish hydrolysate
A method for the preparation of energy food incorporating fish hydrolysates, sugar, cocoa, malt extract etc. is described. The product has good consumer appeal. The preparation does not impart any bitter taste of the hydrolysate to the final product irrespective of the type of fish used for preparing the hydrolysate. It freely mixes with hot or cold milk and the resulting drink is adjudged to be very palatable
Covariant gauges at finite temperature
A prescription is presented for real-time finite-temperature perturbation
theory in covariant gauges, in which only the two physical degrees of freedom
of the gauge-field propagator acquire thermal parts. The propagators for the
unphysical degrees of freedom of the gauge field, and for the Faddeev-Popov
ghost field, are independent of temperature. This prescription is applied to
the calculation of the one-loop gluon self-energy and the two-loop interaction
pressure, and is found to be simpler to use than the conventional one.Comment: 11 pages plus pictex figures (the leading-temperature contributions
given in sect 3.1 were incomplete) CERN-TH-6491/92, published in Nucl Phys
B383 (1992) 60
Exact Minimum Eigenvalue Distribution of an Entangled Random Pure State
A recent conjecture regarding the average of the minimum eigenvalue of the
reduced density matrix of a random complex state is proved. In fact, the full
distribution of the minimum eigenvalue is derived exactly for both the cases of
a random real and a random complex state. Our results are relevant to the
entanglement properties of eigenvectors of the orthogonal and unitary ensembles
of random matrix theory and quantum chaotic systems. They also provide a rare
exactly solvable case for the distribution of the minimum of a set of N {\em
strongly correlated} random variables for all values of N (and not just for
large N).Comment: 13 pages, 2 figures included; typos corrected; to appear in J. Stat.
Phy
Same-sign W pair production as a probe of double parton scattering at the LHC
We study the production of same-sign W boson pairs at the LHC in double
parton interactions. Compared with simple factorised double parton
distributions (dPDFs), we show that the recently developed dPDFs, GS09, lead to
non-trivial kinematic correlations between the W bosons. A numerical study of
the prospects for observing this process using same-sign dilepton signatures,
including same-sign WWjj, di-boson and heavy flavour backgrounds, at 14 TeV
centre-of-mass energy is then performed. It is shown that a small excess of
same-sign dilepton events from double parton scattering over a background
dominated by single scattering WZ(gamma*) production could be observed at the
LHC.Comment: 14 pages, 8 figures. Added references, slight changes in the text
Ultra-High Carrier Mobilities in Ferroelectric Domain Wall Corbino Cones at Room Temperature
Recently, electrically conducting heterointerfaces between dissimilar band-insulators (such as lanthanum aluminate and strontium titanate) have attracted considerable research interest. Charge transport has been thoroughly explored and fundamental aspects of conduction firmly established. Perhaps surprisingly, similar insights into conceptually much simpler conducting homointerfaces, such as the domain walls that separate regions of different orientations of electrical polarisation within the same ferroelectric band-insulator, are not nearly so well-developed. Addressing this disparity, we herein report magnetoresistance in approximately conical 180° charged domain walls, which occur in partially switched ferroelectric thin film single crystal lithium niobate. This system is ideal for such measurements: firstly, the conductivity difference between domains and domain walls is extremely and unusually large (a factor of at least 1013) and hence currents driven through the thin film, between planar top and bottom electrodes, are overwhelmingly channelled along the walls; secondly, when electrical contact is made to the top and bottom of the domain walls and a magnetic field is applied along their cone axes (perpendicular to the thin film surface), then the test geometry mirrors that of a Corbino disc, which is a textbook arrangement for geometric magnetoresistance measurement. Our data imply carriers at the domain walls with extremely high room temperature Hall mobilities of up to ~ 3,700cm2V-1s-1. This is an unparalleled value for oxide interfaces (and for bulk oxides too) and is most comparable to mobilities in other systems typically seen at cryogenic, rather than at room, temperature
Age at first birth in women is genetically associated with increased risk of schizophrenia
Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe
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