381 research outputs found
Investigation of the quasifission process by theoretical analysis of experimental data of fissionlike reaction products
The fusion excitation function is the important quantity in planning
experiments for the synthesis of superheavy elements. Its values seem to be
determined by the experimental study of the hindrance to complete fusion by the
observation of mass, angular and energy distributions of the fissionlike
fragments. There is ambiguity in establishment of the reaction mechanism
leading to the observed binary fissionlike fragments. The fissionlike fragments
can be produced in the quasifission, fast fission, and fusion-fission processes
which have overlapping in the mass (angular, kinetic energy) distributions of
fragments. The branching ratio between quasifission and complete fusion
strongly depends on the characteristics of the entrance channel. In this paper
we consider a wide set of reactions (with different mass asymmetry and mass
symmetry parameters) with the aim to explain the role played by many quantities
on the reaction mechanisms. We also present the results of study of the
Ca+Bk reaction used to synthesize superheavy nuclei with Z = 117
by the determination of the evaporation residue cross sections and the
effective fission barriers of excited nuclei formed along the
de-excitation cascade of the compound nucleus.Comment: 21 pages, 15 figures, 2 table
COMPARISON OF CHARACTERISTICS OF BIM VISUALIZATION AND INTERACTIVE APPLICATION BASED ON WEBGL AND GAME ENGINE
How can we make the building information model accessible to all stakeholders on a project? An efficient approach is to access the building information model is to use the software that created the model. However, not all stakeholders will be able to use this highly specialized software—due to lack of training and expensive licences—even if some software specially developed a simplified version of the viewer to browse the model, however, it still failed to provide convenient access to these models for participants from a wide range of backgrounds. The current development of BIM model visualization and interactive applications is mainly based on two technologies: WebGL and game engines. What is the general workflow of WebGL and Game Engines supporting application development? What are their characteristics respectively? What conditions are restricted? There are no relevant academic papers to discuss and compare these two types of platforms. Therefore, this is the content of this essay. By comparing the workflow and characteristics of BIM visualization and interactive application development based on WebGL and Game Engine, it can provide a reference for heritage building managers when planning the development of relevant application tools and meet the participation needs of different stakeholders
"Pi of the Sky" - all-sky, real-time search for fast optical transients
An apparatus to search for optical flashes in the sky is described. It has
been optimized for gamma ray bursts (GRB) optical counterparts. It consists of
2x16 cameras covering all the sky. The sky is monitored continuously and the
data are analysed on-line. It has self-triggering capability and can react to
external triggers with negative delay. The prototype with two cameras has been
installed at Las Campanas (Chile) and is operational from July 2004. The paper
presents general idea and describes the apparatus in detail. Performance of the
prototype is briefly reviewed and perspectives for the future are outlined
Photoproduction of K+ Δ(1405) → K+ π0 Σ0 extending to forward angles and low momentum transfer
K+ Lambda (1405) photoproduction has been studied at the BGOOD experiment via the all neutral decay, Lambda(1405)-> Sigma0 Pi0. The unique BGOOD experimental setup allows both the cross section and
invariant mass Lamba(1405) distribution (line shape) to be measured over a broad K+ polar angle range, extending to extreme forward K+ angles unattainable at previous experiments.
Evidence is provided for the role of a triangle singularity driven by the N*(2030)⁎
resonance, which appears to contribute significantly to K+Lambda(1405)
photoproduction. This is observed in the integrated cross section which was determined with unprecedented energy resolution and supported by the angular distributions. The measured line shape is also in agreement with the previous results of CLAS and ANKE, and is consistent with two poles derived in χPT based models
Phylogenetic and Molecular Characterization of a 23S Ribosomal-Rna Gene Positions the Genus Campylobacter in the Epsilon-Subdivision of the Proteobacteria and Shows That the Presence of Transcribed Spacers Is Common in Campylobacter Spp
The nucleotide sequence of a 23S rRNA gene of Campylobacter coli VC167 was determined. The primary sequence of the C. coli 23S rRNA was deduced, and a secondary-structure model was constructed. Comparison with Escherichia coli 23S rRNA showed a major difference in the C. coli rRNA at approximately position 1170 (E. coli numbering) in the form of an extra sequence block approximately 147 bp long. PCR analysis of 31 other strains of C. coli and C. jejuni showed that 69% carried a transcribed spacer of either ca, 147 or ca. 37 bp. Comparison of all sequenced Campylobacter transcribed spacers showed that the Campylobacter inserts were related in sequence and percent G+C content. All Campylobacter strains carrying transcribed spacers in their 23S rRNA genes produced fragmented 23S rRNAs. Other strains which produced unfragmented 23S rRNAs did not appear to carry transcribed spacers at this position in their 23S rRNA genes. At the 1850 region (E. coli numbering), Campylobacter 23S rRNA displayed a base pairing signature most like that of the beta and gamma subdivisions of the class Proteobacteria, but in the 270 region, Campylobacter 23S rRNA displayed a helix signature which distinguished it from the alpha, beta, and gamma subdivisions. Phylogenetic analysis comparing C. coli VC167 23S rRNA and a C. jejuni TGH9011 (ATCC 43431) 23S rRNA with 53 other completely sequenced (eu)bacterial 23S rRNAs showed that the two campylobacters form a sister group to the alpha, beta, and gamma proteobacterial 23S rRNAs, a positioning consistent with the idea that the genus Campylobacter belongs to the epsilon subdivision of the class Proteobacteria
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal
Measurement of the γ n → K0 0 differential cross section over the K∗ threshold
The differential cross section for the quasi-free photoproduction reaction gamma(n)-> K-0 Sigma(0) was measured at BGOOD at ELSA from threshold to a centre-of-mass energy of 2400 MeV. Close to threshold the results are consistent with existing data and are in agreement with partial wave analysis solutions over the full measured energy range, with a large coupling to the Delta(1900)1/2(-) evident. This is the first dataset covering the K* threshold region, where there are model predictions of dynamically generated vector meson-baryon resonance contributions
Evidence of a dibaryon spectrum in coherent π0π0d photoproduction at forward deuteron angles
The coherent reaction, was studied with the BGOOD experiment at ELSA from threshold to a centre-of-mass energy of 2850 MeV. A full kinematic reconstruction was made, with final state deuterons identified in the forward spectrometer and decays in the central BGO Rugby Ball. The strength of the differential cross section exceeds what can be described by models of coherent photoproduction and instead supports the three isoscalar dibaryon candidates reported by the ELPH collaboration at 2.38, 2.47 and 2.63 GeV/c2. A low mass enhancement in the invariant mass is also observed at the
⁎
centre-of-mass energy which is consistent with the ABC effect. At higher centre-of-mass energies, a narrow peak in the invariant mass at 2114 MeV/c2 with a width of 20 MeV/c2 supports a sequential two-dibaryon decay mechanism
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