Synthesis of platinum silicide at platinum/silicon oxide interface by photon irradiation

The synthesis of platinum silicide at a Pt/SiOx interface by photon irradiation was investigated using transmission electron microscopy. A platinum silicide, Pt₂Si, was successfully formed at the Pt/SiOx interface by irradiation with 680 and 140 eV photons, but not by irradiation with 80 eV photons. Silicide formation was also induced by irradiation with electrons of energy 75 keV. The amount of silicide formed by photon irradiation was lower than the amount obtained by electron irradiation. Silicide formation by both photon and electron irradiation was accompanied by Si depletion in amorphous SiOx. The experimental results indicate that silicide formation is induced by electronic excitation. A possible mechanism for silicide formation is proposed on the basis of the results

Neutrino Interferometry In Curved Spacetime

Gravitational lensing introduces the possibility of multiple (macroscopic) paths from an astrophysical neutrino source to a detector. Such a multiplicity of paths can allow for quantum mechanical interference to take place that is qualitatively different to neutrino oscillations in flat space. After an illustrative example clarifying some under-appreciated subtleties of the phase calculation, we derive the form of the quantum mechanical phase for a neutrino mass eigenstate propagating non-radially through a Schwarzschild metric. We subsequently determine the form of the interference pattern seen at a detector. We show that the neutrino signal from a supernova could exhibit the interference effects we discuss were it lensed by an object in a suitable mass range. We finally conclude, however, that -- given current neutrino detector technology -- the probability of such lensing occurring for a (neutrino-detectable) supernova is tiny in the immediate future.Comment: 25 pages, 1 .eps figure. Updated version -- with simplified notation -- accepted for publication in Phys.Rev.D. Extra author adde

DD-4 Synthesis of Planar Microwave Band-pass Filter based on Foster-type Network and Normal Mode Expansion Method

A new synthesis method of microwave filter circuit based on the Foster-type network representation is proposed, where two port impedance matrix which realizes the desired frequency characteristics and that of any microwave circuit structure are expanded into Foster-type network representation; microwave filter circuit can be synthesizedby matching the both network representation. In this paper fundamental idea of synthesis method and practical examples are explained.1992 IEEE MTT-S International Microwave Symposium Digest, June 1-5, 1992, Albuquerque Convention Center, Albuquerque, New Mexic

Mouse SPNS2 Functions as a Sphingosine-1-Phosphate Transporter in Vascular Endothelial Cells

Sphingosine-1-phosphate (S1P), a sphingolipid metabolite that is produced inside the cells, regulates a variety of physiological and pathological responses via S1P receptors (S1P1–5). Signal transduction between cells consists of three steps; the synthesis of signaling molecules, their export to the extracellular space and their recognition by receptors. An S1P concentration gradient is essential for the migration of various cell types that express S1P receptors, such as lymphocytes, pre-osteoclasts, cancer cells and endothelial cells. To maintain this concentration gradient, plasma S1P concentration must be at a higher level. However, little is known about the molecular mechanism by which S1P is supplied to extracellular environments such as blood plasma. Here, we show that SPNS2 functions as an S1P transporter in vascular endothelial cells but not in erythrocytes and platelets. Moreover, the plasma S1P concentration of SPNS2-deficient mice was reduced to approximately 60% of wild-type, and SPNS2-deficient mice were lymphopenic. Our results demonstrate that SPNS2 is the first physiological S1P transporter in mammals and is a key determinant of lymphocyte egress from the thymus

MoniPoly---An Expressive qq-SDH-Based Anonymous Attribute-Based Credential System

Modern attribute-based anonymous credential (ABC) systems benefit from special encodings that yield expressive and highly efficient show proofs on logical statements. The technique was first proposed by Camenisch and Groß, who constructed an SRSA-based ABC system with prime-encoded attributes that offers efficient AND, OR and NOT proofs. While other ABC frameworks have adopted constructions in the same vein, the Camenisch-Groß ABC has been the most expressive and asymptotically most efficient proof system to date, even if it was constrained by the requirement of a trusted message-space setup and an inherent restriction to finite-set attributes encoded as primes. In this paper, combining a new set commitment scheme and a SDH-based signature scheme, we present a provably secure ABC system that supports show proofs for complex statements. This construction is not only more expressive than existing approaches, it is also highly efficient under unrestricted attribute space due to its ECC protocols only requiring a constant number of bilinear pairings by the verifier; none by the prover. Furthermore, we introduce strong security models for impersonation and unlinkability under adaptive active and concurrent attacks to allow for the expressiveness of our ABC as well as for a systematic comparison to existing schemes. Given this foundation, we are the first to comprehensively formally prove the security of an ABC with expressive show proofs. Specifically, we prove the security against impersonation under the $q$-(co-)SDH assumption with a tight reduction. Besides the set commitment scheme, which may be of independent interest, our security models can serve as a foundation for the design of future ABC systems

A Bayesian approach to the Japanese Black cattle carcass genetic evaluation

Volumes of the routine carcass field data used in the official genetic evaluation for carcass traits in Japanese Black cattle are increasing rapidly. The purposes of this paper are to describe a Bayesian approach via Gibbs sampling (GS) to be used in the Japanese Black carcass genetic evaluation, and in particular using a very large carcass field data, to compare breeding values for sires and dams of animals with records estimated using GS and the conventional empirical best linear unbiased prediction (EBLUP) employing the restricted maximum likelihood (REML) estimates of variance components. The total of six carcass traits evaluated were carcass weight, rib eye area, rib thickness, subcutaneous fat thickness, estimated muscle yield percentage and marbling score. As prior distributions for GS, uniform, normal and independently scaled inverted chi-square distributions with degree of belief and scale parameters of –2 and 0 were used for nuisance parameters, breeding values and variance components, respectively. The posterior means were calculated using every 10th sample from a total of 90 000 samples, after 10 000 samples had been discarded. Moment and rank correlations between breeding values estimated by the GS and the REML-EBLUP were all very close to one, and the coefficients and the intercepts for linear regression of the GS on the REML-EBLUP estimates were substantially one and zero, respectively, showing a very good agreement between breeding value estimation by the GS and the REML-EBLUP

Influence of extrusion conditions on the superplastic properties of a Mg-8%Li alloy processed at room temperature by equal-channel angular pressing

It is well known that alpha+beta duplex structure Mg-Li alloys exhibit an excellent superplastic ductility at intermediate temperatures. Moreover, many researchers have demonstrated that the ductility enhancement in Mg alloys could be achieved by refining its grain structure using conventional thermo-mechanical treatments, powder metallurgy and severe plastic deformation. Among the severe plastic deformation methods, equal-channel angular pressing (ECAP) can produce uncontaminated, fully dense and large bulk materials with submicrometer or even nanometer grain structures effectively.Processing by ECAP was successfully performed on a Mg-8mass%Li alloy at room temperature using a solid die having an internal channel angle of 135 degree. A refined and uniform dispersion of the alpha and beta phases was achieved by applying ECAP processing for four passes at room temperature by comparison with the alloy in the extruded condition. The elongations to failure in tensile testing increase with a decrease in the extrusion temperature but they are reasonably independent of the extrusion speed within the range from 1-10mm/s. The Mg-8%Li alloy exhibits excellent superplastic properties at 473K after extrusion and ECAP including a maximum elongation of 1780%. The strain rate sensitivity was measured as 0.4-0.6 under the optimum superplastic conditions