Stable CW laser based on low thermal expansion ceramic cavity with 49 mHz/s frequency drift

We describe a CW laser stabilized to a low thermal expansion ceramic cavity which has a lower frequency drift rate than cavities based on ultralow-expansion glass (ULE), which are widely used as optical references. Two identical optical cavities with spacers of different material, ceramic and ULE, were assembled and the optical frequencies locked to each of these cavities were compared. The optical frequency drifts of both CW lasers were measured to within a precision of 10−11 in one second over the course of one year. The ceramic cavity had a long-term frequency drift rate of 4.9 mHz/s and the ULE cavity had one of 23 mHz/s

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

Development of Auto Scaling Method for 3D Rock Fragmentation Measurement System

Fragmentation Distribution is one of the important aspects of mining operations as it affects productivities on the majority of Mine-to-Mill operations. Nevertheless the significance of fragmentation management, the mining industry has relied on 2D image based fragmentation measurement system which poses many downsides. To overcome the drawbacks of current 2D fragmentation measurement system, 3D Rock Fragmentation Measurement System has been proposed with using 3D photogrammetry technologies. One of the common difficulty of fragmentation measurement system is scaling of the object, which is an essential component to secure the accuracy of particle size distribution. In this study, the actual scales and size information of objects have been obtained by measuring the acceleration when moving between the photographing points and giving the information of the distance obtained from the acceleration. The developed system would be equipped with the 3D Rock Fragmentation Measurement System

Orbital ordering in charge transfer insulators

We discuss a new mechanism of orbital ordering, which in charge transfer insulators is more important than the usual exchange interactions and which can make the very type of the ground state of a charge transfer insulator, i.e. its orbital and magnetic ordering, different from that of a Mott-Hubbard insulator. This purely electronic mechanism allows us to explain why orbitals in Jahn-Teller materials typically order at higher temperatures than spins, and to understand the type of orbital ordering in a number of materials, e.g. K_2CuF_4, without invoking the electron-lattice interaction.Comment: 4 pages, 2 figure

Carbon Deposition Model for Oxygen-Hydrocarbon Combustion, Volume 2

Presented are details of the design, fabrication, and testing of subscale hardware used in the evaluation of carbon deposition characteristics of liquid oxygen and three hydrocarbon fuels for both main chamber and preburner/gas generator operating conditions. In main chamber conditions, the deposition of carbon on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and at chamber pressures of 1000 to 1500 psia. No carbon deposition on chamber walls was detected at these main chamber mixture ratios. In preburner/gas generator operating conditions, the deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60 and at chamber pressures of 720 to 1650 psia. The results of the tests showed carbon deposition rate to be a strong function of mixture ratio and a weak function of chamber pressure. Further analyses evaluated the operational concequences of carbon deposition on preburner/gas generator performance. This is Volume 2 of the report, which contains data plots of all the test programs

High prevalence of multidrug-resistant Pneumococcal molecular epidemiology network clones among Streptococcus pneumoniae isolates from adult patients with community-acquired pneumonia in Japan

AbstractA total of 141 Streptococcus pneumoniae isolates from patients with community-acquired pneumonia were collected from May 2003 through October 2004. The strains were tested for antimicrobial agent susceptibility, serotype and genotype by multilocus sequence typing (MLST) and the presence of the pilus rlrA islet. MLST analysis identified 49 sequence types (STs), of which 19 were novel. eBURST analysis using the MLST database (3773 STs) grouped the isolates into 27 clonal complexes and three singletons. A total of 92 (65.2%) isolates were related to ten of the 43 international Pneumococcal Molecular Epidemiology Network (PMEN) clones; major clones found were multidrug-resistant Netherlands3-31 [clonal complex (CC) 180], Taiwan19F-14 (CC271), Taiwan23F-15 (CC242), and Colombia23F-26 (CC138) (the latter new to Asia). We adopted univariate and multiple logistic regression models to identify factors associated with PMEN CCs. Multivariate analysis showed that multidrug resistance (OR 6.3; 95% CI 2.0–22.9), carriage serogroups (OR 7.2; 95% CI 2.5–23.7), prevalence of rlrA (OR 12.6; 95% CI 3.6–59.7) and central nervous system-related disorders (OR 7.7; 95% CI 1.8–48.4) were independently associated with PMEN CCs. Our data indicate that multidrug-resistant PMEN clones are highly prevalent, contributing to the high frequency of resistance to antimicrobial agents in Japan, and suggest that certain predisposing factors in patients contribute to the high frequency of these clones

Hilbert schemes and simple singularities An and Dn

For any finite subgroup G of SL(2, C) of order n, we consider a certain subscheme HilbG(A2 ) of Hilbn(A2 ) consisting of G-invariant 0-dimensional subschemes of length n. We prove without using the classification of finite subgroups in SL(2,C) that HilbG(A2 ) is a minimal resolution of a simple singularity A2 /G in the canonical manner. Any point of the exceptional set is a G-invariant 0-dimensional subscheme of A2 with support the origin, to which we associate the ideal sheaf I defining the subscheme. A minimal G-submodule of I generating the O A2-module I is a one dimensional trivial G-module plus one or two nontrivial mutually distinct irreducible G-modules. This gives a bijective correpondence between the set of all the irreducible components of the exceptional set and the set of all the equivalence classes of irreducible G-modules, which turns out to be the ( classical) McKay correspondence

Ferromagnetism and large negative magnetoresistance in Pb doped Bi-Sr-Co-O misfit-layer compound

Ferromagnetism and accompanying large negative magnetoresistance in Pb-substituted Bi-Sr-Co-O misfit-layer compound are investigated in detail. Recent structural analysis of (Bi,Pb)${}_2$Sr${}_{3}$Co${}_2$O${}_9$, which has been believed to be a Co analogue of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta}$, revealed that it has a more complex structure including a CoO${}_2$ hexagonal layer [T. Yamamoto {\it et al.}, Jpn. J. Appl. Phys. {\bf 39} (2000) L747]. Pb substitution for Bi not only introduces holes into the conducting CoO${}_2$ layers but also creates a certain amount of localized spins. Ferromagnetic transition appears at $T$ = 3.2 K with small spontaneous magnetization along the $c$ axis, and around the transition temperature large and anisotropic negative magnetoresistance was observed. This compound is the first example which shows ferromagnetic long-range order in a two-dimensional metallic hexagnonal CoO${}_2$ layer.Comment: 8 pages including eps figures. To be published in J. Phys. Soc. Jp

BPS Monopole Equation in Omega-background

We study deformed supersymmetries in N=2 super Yang-Mills theory in the Omega-backgrounds characterized by two complex parameters $\epsilon_1, \epsilon_2$. When one of the $\epsilon$-parameters vanishes, the theory has extended supersymmetries. We compute the central charge of the algebra and obtain the deformed BPS monopole equation. We examine supersymmetries preserved by the equation.Comment: 14 pages, typos corrected, published version in JHE