Analytical method for designing grating compensated dispersion-managed soliton systems

This paper was published in Journal of Optical Society of America B and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=JOSAB-21-4-706. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. © 2004 The Optical Society.Peer reviewedPublisher PD

Crack analysis of concrete beams based on pseudo-discrete crack model

Crack widths are important considerations in both serviceability and durability design of concrete structures and should be evaluated to ensure compliance with design limits. However, existing empirical formulas for maximum crack width prediction are discrepant with each other, and they cannot reveal key information such as crack number and crack spacing. To obtain such information, finite element analysis has to be adopted. However, conventional finite element analysis has its limits in carrying out crack analysis. Particularly, the common smeared crack models, which do not realistically reflect bond-slip of reinforcing bars, would not give correct crack widths. In contrast, the discrete crack models are difficult to apply because of the need to adaptively generate discrete crack elements according to the cracks formed during the loading process. In this paper, a pseudo-discrete crack model is developed for finite element implementation. The conventional smeared crack model is transformed and reformulated, and a novel crack queuing algorithm is introduced for crack analysis. The method has been applied to analyse concrete beams in the literature. It is demonstrated that the computational results of crack number, spacing and widths agree closely with the measured results

Effects of metallic spacer in layered superconducting Sr2(Mgy_yTi1−y_{1-y})O3FeAs

The highly two-dimensional superconducting system Sr2(Mg$_y$Ti$_{1-y}$)O3FeAs, recently synthesized in the range of 0.2 < y < 0.5, shows an Mg concentration-dependent $T_c$. Reducing the Mg concentration from y=0.5 leads to a sudden increase in $T_c$, with a maximum $T_c$ ~40 K at y=0.2. Using first principles calculations, the unsynthesized stoichiometric y=0 and the substoichiometric y=0.5 compounds have been investigated. For the 50% Mg-doped phase (y=0.5), Sr2(Mg$_y$Ti$_{1-y}$)O3 layers are completely insulating spacers between FeAs layers, leading to the fermiology such as that found for other Fe pnictides. At y=0, representing a phase with metallic Sr2TiO3 layers, the $\Gamma$-centered Fe-derived Fermi surfaces (FSs) considerably shrink or disappear. Instead, three $\Gamma$-centered Ti FSs appear, and in particular two of them have similar size, like in MgB2. Interestingly, FSs have very low Fermi velocity in large fractions: the lowest being 0.6$\times10^6$ cm/s. Furthermore, our fixed spin moment calculations suggest the possibility of magnetic ordering, with magnetic Ti and nearly nonmagnetic Fe ions. These results indicate a crucial role of Sr2(Mg$_y$Ti$_{1-y}$)O3 layers in this superconductivity.Comment: 7 pages; Proceedings of ICSM-201

Measurement of Cosmic-ray Muons and Muon-induced Neutrons in the Aberdeen Tunnel Underground Laboratory

We have measured the muon flux and production rate of muon-induced neutrons at a depth of 611 m water equivalent. Our apparatus comprises three layers of crossed plastic scintillator hodoscopes for tracking the incident cosmic-ray muons and 760 L of gadolinium-doped liquid scintillator for producing and detecting neutrons. The vertical muon intensity was measured to be $I_{\mu} = (5.7 \pm 0.6) \times 10^{-6}$ cm$^{-2}$s$^{-1}$sr$^{-1}$. The yield of muon-induced neutrons in the liquid scintillator was determined to be $Y_{n} = (1.19 \pm 0.08 (stat) \pm 0.21 (syst)) \times 10^{-4}$ neutrons/($\mu\cdot$g$\cdot$cm$^{-2}$). A fit to the recently measured neutron yields at different depths gave a mean muon energy dependence of $\left\langle E_{\mu} \right\rangle^{0.76 \pm 0.03}$ for liquid-scintillator targets.Comment: 14 pages, 17 figures, 3 table

The internal transcribed spacer rDNA specific markers for identification of Zanthoxylum piperitum

Genus Zanthoxylum which has significant medical importance belongs to the family Rutaceae. This investigation was aimed to identify total internal transcribed spacer (ITS) regions among the nuclear ribosomal DNA (nrDNA) to distinguish Zanthoxylum piperitum from Zanthoxylum sichinifolium. The nrDNA ITS sequence markers were developed by using universal ITS5/ITS4 primer pairs. Speciesspecific primers amplified the total ITS region sequence named ITS1-YL1 and ITS1-YL2. These were amplified efficiently when paired with universal primer ITS4 in Z. piperitum, but not in Z. schinifolium. ITS1-YL1/ITS4 or ITS1-YL2/ITS4 preferential amplification was shown to be particularly useful for detection and distribution of Z. piperitum from other plant species, especially Z. schinifolium. These primers are useful to study the structure of Rutaceae family. Such identifications will be helpful for phylogenetic analysis in intraspecies population of the genus Zanthoxylum.Key words: Zanthoxylum piperitum, rDNA Int-sp markers, phylogenetic relationship, ribosomal DNA, internal transcribed spacer

Ribosomal DNA internal transcribed spacer 1 and internal transcribed spacer 2 regions as targets for molecular identification of medically important Zanthoxylum schinifolium

Molecular approaches are now being developed to provide a more rapid and objective identification compared to traditional phenotypic methods. Nuclear ribosomal DNA (nrDNA) targets, especially internal transcribed spacer 1 and 2 (ITS1 and ITS2), have been widely used for molecular identification of some plants and fungi. We therefore conducted an investigation in the identification of the fifth medically important Zanthoxylum schinifolium ecotypes using the common primers of the ITS region. About 620 bp fragments were obtained and the sequences of the polymerase chain reaction (PCR) products were tested. The sequence length, G+C content (%), DNA alignment and pariwise nucleotidecomparisons demonstrated 98.8 to 100% sequence identities in the total ITS region, 98.3 to 100% identities in the ITS1 region and 99.5 to 100% in the ITS2 region. Comparative analysis using GenBank reference data showed that the exclusive reported data showed 100% identities with BEMR, CWDO, HCDC, JDGG and GJGD in the ITS1 region and 100% identities with thirteen ecotypes except BEMR and GRDG in the ITS2 region. The fifth different ecotypes were classified into five groups and theidentification of medically important Z. schinifolium was highly improved due to the augmentation of our current ITS sequences

Novel Phases and Finite-Size Scaling in Two-Species Asymmetric Diffusive Processes

We study a stochastic lattice gas of particles undergoing asymmetric diffusion in two dimensions. Transitions between a low-density uniform phase and high-density non-uniform phases characterized by localized or extended structure are found. We develop a mean-field theory which relates coarse-grained parameters to microscopic ones. Detailed predictions for finite-size ($L$) scaling and density profiles agree excellently with simulations. Unusual large-$L$ behavior of the transition point parallel to that of self-organized sandpile models is found.Comment: 7 pages, plus 6 figures uuencoded, compressed and appended after source code, LATeX, to be published as a Phys. Rev. Let