53 research outputs found

    Spectrum and Wave Functions of Excited States in Lattice Gauge Theory

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    We suggest a new method to compute the spectrum and wave functions of excited states. We construct a stochastic basis of Bargmann link states, drawn from a physical probability density distribution and compute transition amplitudes between stochastic basis states. From such transition matrix we extract wave functions and the energy spectrum. We apply this method to U(1)2+1U(1)_{2+1} lattice gauge theory. As a test we compute the energy spectrum, wave functions and thermodynamical functions of the electric Hamiltonian and compare it with analytical results. We find excellent agreement. We observe scaling of energies and wave functions in the variable of time. We also present first results on a small lattice for the full Hamiltonian including the magnetic term.Comment: Lattice 2008 conferenc

    Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

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    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a wellcharacterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 mu m diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 angstrom ngstrom were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.11Ysciescopu

    Coherent soft X-ray diffraction imaging of coliphage PR772 at the Linac coherent light source

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    Single-particle diffraction from X-ray Free Electron Lasers offers the potential for molecular structure determination without the need for crystallization. In an effort to further develop the technique, we present a dataset of coherent soft X-ray diffraction images of Coliphage PR772 virus, collected at the Atomic Molecular Optics (AMO) beamline with pnCCD detectors in the LAMP instrument at the Linac Coherent Light Source. The diameter of PR772 ranges from 65–70 nm, which is considerably smaller than the previously reported ~600 nm diameter Mimivirus. This reflects continued progress in XFEL-based single-particle imaging towards the single molecular imaging regime. The data set contains significantly more single particle hits than collected in previous experiments, enabling the development of improved statistical analysis, reconstruction algorithms, and quantitative metrics to determine resolution and self-consistency

    Retracted: A survey of jundishapur medical sciences university students viewpoints in Ahvaz considering the effective components in the marketing process of libraries based on the principles of marketing mix (9P's model)

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    This article was withdrawn and retracted by the Journal of Fundamental and Applied Sciences and has been removed from AJOL at the request of the journal Editor in Chief and the organisers of the conference at which the articles were presented (www.iccmit.net). Please address any queries to [email protected]

    Single-particle structure determination by X-ray free-electron lasers: Possibilities and challenges

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    Single-particle structure recovery without crystals or radiation damage is a revolutionary possibility offered by X-ray free-electron lasers, but it involves formidable experimental and data-analytical challenges. Many of these difficulties were encountered during the development of cryogenic electron microscopy of biological systems. Electron microscopy of biological entities has now reached a spatial resolution of about 0.3 nm, with a rapidly emerging capability to map discrete and continuous conformational changes and the energy landscapes of biomolecular machines. Nonetheless, single-particle imaging by X-ray free-electron lasers remains important for a range of applications, including the study of large “electron-opaque” objects and time-resolved examination of key biological processes at physiological temperatures. After summarizing the state of the art in the study of structure and conformations by cryogenic electron microscopy, we identify the primary opportunities and challenges facing X-ray-based single-particle approaches, and possible means for circumventing them

    Unconstrained melting inside a sphere

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    This paper presents both numerical and experimental investigations on unconstrained melting of phase change material (PCM) using n-octadecane inside a spherical container. Experimental studies are performed for three different wall temperatures of the container at 35 °C, 40 °C and 45 °C with the PCM at an initial sub-cooling of 1 °C below the melting temperature. Numerical simulations are performed for axisymmetric melting of PCM inside a sphere using the Fluent 6.3 software. After validating the numerical results with the experimental data, the effect of shell diameter on melting at different Stefan numbers is studied numerically. The results indicate that the melting rate is high at the beginning of melting due to perfect contact between the hot shell and solid PCM. The melting rate reduces with progressing time when a layer of molten PCM is formed between the shell and solid PCM. After this stage, the effect of conduction heat transfer diminishes and restricted to the bottom of sphere where the solid PCM sinks. At both sides of the sphere, convection heat transfer in the liquid PCM becomes the dominant mode for melting
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