[en] A survey and analysis of Protein Data Bank (PDB) depositions from international synchrotron radiation facilities, based on the latest released PDB entries, are reported. The results (< http://asdp.bnl.gov/asda/Libraries/>) show that worldwide, every year since 1999, more than 50% of the deposited X-ray structures have used synchrotron facilities, reaching 75% by 2003. In this web-based database, all PDB entries among individual synchrotron beamlines are archived, synchronized with the weekly PDB release. Statistics regarding the quality of experimental data and the refined model for all structures are presented, and these are analysed to reflect the impact of synchrotron sources. The results confirm the common impression that synchrotron sources extend the size of structures that can be solved with equivalent or better quality than home sources

[en] We study the general Higgs--weak-boson coupling with CP violation via the process e⁺e^-→fbar fh. We categorize the signal channels by the subprocesses of Zh production and ZZ fusion and construct four CP asymmetries by exploiting polarized e⁺e^- beams. We find complementarity among the subprocesses and the asymmetries to probe the real and imaginary parts of the CP-violating form factor. Certain asymmetries with unpolarized beams can retain significant sensitivity to the coupling. We conclude that at a linear collider with high luminosity, the CP-odd ZZh coupling may be sensitively probed via measurements of the asymmetries

[en] Owing to increased emphasis on renewable resources, the development of suitable isolated power generators driven by energy sources, the development of suitable isolated power generators driven by energy sources such as photovoltaic, wind, small hydroelectric, biogas and etc. has recently assumed greater significance. A single phase capacitor self excited induction generator has emerged as a suitable candidate of isolated power sources. This paper presents performance analysis of a single phase self-excited induction generator driven by photovoltaic (P V) system for low power isolated stand-alone applications. A single phase induction machine can work as a self-excited induction generator when its rotor is driven at suitable speed by an photovoltaic powered do motor. Its excitation is provided by connecting a single phase capacitor bank at a stator terminals. Either to augment grid power or to get uninterrupted power during grid failure stand-alone low capacity ac generators are used. These are driven by photovoltaic, wind power or I C engines using kerosene, diesel, petrol or biogas as fuel. Self-excitation with capacitors at the stator terminals of the stator terminals of the induction machines is well demonstrated experimentally on a P V powered dc motor-induction machine set. The parameters and the excitation requirements of the induction machine run in self-excited induction generator mode are determined. The effects of variations in prime mover speed,terminal capacitance and load power factor on the machine terminal voltage are studied

[en] SrRuO₃ thin films deposited on (001) LaAlO₃ substrates by 90 degree off-axis sputtering at 600 degreeC were studied by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Both AFM and cross-section TEM investigations show that the films have a rough surface. Plan-view TEM studies demonstrate that the films are composed of all three different types of orientation domains (twins). These domain structures and surface morphology are different from the SrRuO₃ film deposited on the (001) SrTiO₃ substrate which has an atomically flat surface and is composed of only the [110]-type domains. The reason for these differences was ascribed as the effect of lattice mismatch across the film/substrate interface. It is proposed that a SrRuO₃ thin film grows on a (001) SrTiO₃ substrate through a two-dimensional nucleation process, while a film on LaAlO₃ grows with three steps: the coherent growth of a few monolayers at the initial stage through a two-dimensional nucleation process; the formation of misfit dislocations when the film reaches a critical thickness; and an island-like growth thereafter due to the nonuniform distribution of stress along the film surface. [copyright] 2001 American Institute of Physics

[en] We study the production at future e⁺e^- linear colliders of the heavy neutral Higgs bosons H and A of the minimal supersymmetric standard model in association with top and bottom quarks. The cross sections have a strong dependence on the parameter tanβ, and thus provide a good way to determine it. At a linear collider with s=0.5--1 TeV and expected integrated luminosities, we find significant sensitivities for determining tanβ. In the supergravity scenario, the sensitivity is particularly strong for tanβ∼>10, reaching a 15% or better measurement. In the general MSSM scenario, the interplay between the 4b and 4t channels results in a good determination for tanβ∼<10, while the sensitivity is weakened for higher values of tanβ

No abstract available

[en] High strength steel box columns are usually fabricated from steel slab by applying welding. The welding process can introduce residual stresses and geometric imperfections into the columns and influence the column strength. In this study, a numerical investigation on the behavior of high strength steel thin-walled box columns under the compression force was carried out. The welding processes were firstly simulated with commercial package ABAQUS in this study to find out the residual stress distributions in high strength steel box column. After that, the column behaviors under the compression were modelled with predefined field from the previous step. The effect of the welding process (including flux-core arc welding and submerged arc welding), heating treatment (including preheating and post-weld heat treatment) and geometrical imperfection on the residual stress field and box column strength was investigated and discussed. (Author)

[en] Using 4π data from the Bevalac streamer chamber, azimuthal correlations for fragment pairs (as in conventional sideward flow analyses) and higher-order multiplets are studied for 400 A MeV Ar + Pb and 1200 A MeV Ar + BaI₂. The authors point out that previous studies of sideward flow have not ruled out the possibility that the effect is dominated by a small number of correlated fragments in each event, as opposed to being a collective motion to which most or all fragments contribute. The authors infer the percentage of the forward going fragments that carry a component of the collective motion

[en] The ratio of neutral Higgs field vacuum expectation values, tanβ, is one of the most important parameters to determine in either the minimal supersymmetric standard model (MSSM) or a general type-II two-Higgs doublet model (2HDM). Assuming an energy and integrated luminosity of √s=500 GeV and L=2000 fb^-1 at a future linear collider (LC), we show that a very accurate determination of tanβ will be possible for low and high tanβ values by measuring the production rates of Higgs bosons and reconstructing Higgs boson decays. In particular, based on a TESLA simulation, and assuming no other light Higgs bosons and 100≤m_A≤200 GeV, we find that the rate for the process e⁺e^-→bb-bar A→bb-bar bb-bar provides a good determination of tanβ at high tanβ. In the MSSM Higgs sector, in the sample case of m_A=200 GeV, we find that the rates for e⁺e^-→bb-bar A+bb-bar H→bb-bar bb-bar and for e⁺e^-→HA→bb-bar bb-bar provide a good determination of tanβ at high and low tanβ, respectively. We also show that the direct measurement of the average total widths of the H and A in e⁺e^-→HA→bb-bar bb-bar events provides an excellent determination of tanβ at large values. In addition, the charged Higgs boson process e⁺e^-→H⁺H^-→tb-bar t-bar b has been studied. The sensitivity to tanβ at the LHC obtained directly from heavy Higgs boson production is briefly compared to the LC results

[en] This study investigates the use of an analytic redundancy in shutdown systems to improve their reliability without installation of redundant sensors in the pressure boundary of nuclear reactor systems. The behavior of process variables can be predicted based on fundamental conservation laws, such as mass, momentum, and energy balance. The predicted quantities are then used as redundant measurements in decision-making. Many techniques to improve reliability and credibility based on analytical redundancy have been studied for nuclear power plants over the last two decades. A limitation of these methods is that they may produce false decisions when operating conditions have changed. During system operation, it is possible that changes in the system be made based on operation procedures. When this happens, the static relationships among measured variables can also change. If these conditions are not considered in the analytical redundancy generation, a false decision will be generated. Current study investigates the use of analytical redundancy in improving the reliability of SDSs. As an application example, the pressurizer low level trip parameter of SDS1 is selected and the mathematical model is used to capture the pressurizer level behavior. The detailed behavior of the pressurizer level, pressure and temperature under different perturbations are considered. Finally, the faults detection algorithm which can substitute physical sensors and instruments is demonstrated using the pressurizer model, and the reliability improvement of SDS1 has been examined