| 1. |
- Ablikim, M., et al.
(författare)
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Study of chi(cJ) decaying into phi K*(892)(K)over-bar
- 2015
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of 106 million psi(3686) events collected with the BESIII detector operated at the BEPCII storage ring, we study for the first time the decays chi(cJ) -> phi(KSK +/-)-K-0 pi(-/+) and chi(cJ) -> phi K+K-pi(0) in the E1 radiative transition psi(3686) -> gamma chi(cJ). The decays are dominated by the three-body decay chi(cJ) -> phi K*(892)(K) over bar. We measure branching fractions for this reaction via the neutral and charged K*(892) and find them consistent with each other within the expectation of isospin symmetry. In the K (K) over bar pi invariant mass distribution, a structure near the K*(892)(K) over bar mass threshold is observed, and the corresponding mass and width are measured to be 1412 +/- 4(stat) +/- 8(sys) MeV/c(2) and Gamma = 84 +/- 12(stat) +/- 40(sys) MeV, respectively. The observed state favors an assignment to the h(1)(1380), considering its possible J(PC) and comparing its mass, width and decay mode to those reported in the Particle Data Group.
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| 2. |
- Wang, Z., et al.
(författare)
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A Sparse Model-Inspired Deep Thresholding Network for Exponential Signal Reconstruction--Application in Fast Biological Spectroscopy
- 2022
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Ingår i: IEEE Transactions on Neural Networks and Learning Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 2162-237X .- 2162-2388. ; 34:10, s. 7578-92
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Tidskriftsartikel (refereegranskat)abstract
- The nonuniform sampling (NUS) is a powerful approach to enable fast acquisition but requires sophisticated reconstruction algorithms. Faithful reconstruction from partially sampled exponentials is highly expected in general signal processing and many applications. Deep learning (DL) has shown astonishing potential in this field, but many existing problems, such as lack of robustness and explainability, greatly limit its applications. In this work, by combining the merits of the sparse model-based optimization method and data-driven DL, we propose a DL architecture for spectra reconstruction from undersampled data, called MoDern. It follows the iterative reconstruction in solving a sparse model to build the neural network, and we elaborately design a learnable soft-thresholding to adaptively eliminate the spectrum artifacts introduced by undersampling. Extensive results on both synthetic and biological data show that MoDern enables more robust, high-fidelity, and ultrafast reconstruction than the state-of-the-art methods. Remarkably, MoDern has a small number of network parameters and is trained on solely synthetic data while generalizing well to biological data in various scenarios. Furthermore, we extend it to an open-access and easy-to-use cloud computing platform (XCloud-MoDern), contributing a promising strategy for further development of biological applications.
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| 3. |
- Abgrall, N., et al.
(författare)
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The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
- 2017
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Ingår i: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1894
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Konferensbidrag (refereegranskat)abstract
- The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
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| 4. |
- Baruzzo, M., et al.
(författare)
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3D effects on RWM physics in RFX-mod
- 2011
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Ingår i: Nuclear Fusion. - 1741-4326 .- 0029-5515. ; 51, s. 083037-
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Tidskriftsartikel (refereegranskat)abstract
- n this paper insights into the behaviour of resistive wall modes (RWMs) in the RFX-mod reversed field pinch device are given, with a focus on 3D issues in the characterization of the m spectrum of the mode and on the study of multi-harmonic coupling.In the first part of the paper the interaction between multiple unstable RWMs is studied and the presence of a coupling between different poloidal components of the most unstable RWM is demonstrated, taking advantage of the flexibility of the RFX-mod control system.In the second part of the work, the dependence of the growth rates of RWMs on a complete set of plasma parameters is studied in order to create a complete and homogeneous database, which permits a careful validation of stability codes.Finally, the experimental data are compared with the code predictions which take into account the 3D structure of conductors around the plasma. The different effects that modify the simple description, where unstable modes can be identified with single Fourier harmonics, appear to be explained by a mixture of toroidicity-induced and 3D eddy current effects.
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| 5. |
- Guo, S. C., et al.
(författare)
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Cancellation of drift kinetic effects between thermal and energetic particles on the resistive wall mode stabilization
- 2016
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 56:7, s. Artno 076006-
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Tidskriftsartikel (refereegranskat)abstract
- Drift kinetic stabilization of the resistive wall mode (RWM) is computationally investigated using MHD-kinetic hybrid code MARS-K following the non-perturbative approach (Liu et al 2008 Phys. Plasmas 15 112503), for both reversed field pinch (RFP) and tokamak plasmas. Toroidal precessional drift resonance effects from trapped energetic ions (EIs) and various kinetic resonances between the mode and the guiding center drift motions of thermal particles are included into the self-consistent toroidal computations. The results show cancellation effects of the drift kinetic damping on the RWM between the thermal particles and EIs contributions, in both RFP and tokamak plasmas, even though each species alone can provide damping and stabilize RWM instability by respective kinetic resonances. The degree of cancellation generally depends on the EIs equilibrium distribution, the particle birth energy, as well as the toroidal flow speed of the plasma.
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| 6. |
- He, X. L., et al.
(författare)
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Fast generation of Schrödinger cat states using a Kerr-tunable superconducting resonator
- 2023
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Schrödinger cat states, quantum superpositions of macroscopically distinct classical states, are an important resource for quantum communication, quantum metrology and quantum computation. Especially, cat states in a phase space protected against phase-flip errors can be used as a logical qubit. However, cat states, normally generated in three-dimensional cavities and/or strong multi-photon drives, are facing the challenges of scalability and controllability. Here, we present a strategy to generate and preserve cat states in a coplanar superconducting circuit by the fast modulation of Kerr nonlinearity. At the Kerr-free work point, our cat states are passively preserved due to the vanishing Kerr effect. We are able to prepare a 2-component cat state in our chip-based device with a fidelity reaching 89.1% under a 96 ns gate time. Our scheme shows an excellent route to constructing a chip-based bosonic quantum processor.
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| 7. |
- Huang, Z. L., et al.
(författare)
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Novel heterocycle-based organic molecules with two-photon induced blue fluorescent emission
- 2003
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 13:4, s. 708-711
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon absorption and two-photon induced blue emission characteristics of a series of heterocycle-based organic molecules are investigated experimentally and by quantum-chemical computations. The molecules consist of a typical A-pi-A' structure, where heterocycle, styryl and formyl groups are employed as A, pi-conjugated and A' moieties, respectively. Experimental results indicate that significant enhancements in the blue emission efficiency and two-photon absorption cross-sections can be achieved by replacing S and O atoms with an N atom in the heterocycle acceptor moiety, which is also supported by the quantum-chemical computations. Additionally, larger two-photon absorption cross-sections can be obtained by choosing appropriate solvents, as indicated by the computations.
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| 8. |
- Liu, Yueqiang, 1971, et al.
(författare)
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Modelling toroidal rotation damping in ITER due to external 3D fields
- 2015
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 55:6
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Tidskriftsartikel (refereegranskat)abstract
- The linear and quasi-linear plasma response to the n = 3 and n = 4 (n is the toroidal mode number) resonant magnetic perturbation (RMP) fields, produced by the in-vessel edge localized mode control coils, is numerically studied for an ITER 15MA H-mode baseline scenario. Both single fluid and fluid-kinetic hybrid models are used. The inclusion of drift kinetic effects does not strongly alter the plasma response compared to the fluid approximation for this ITER plasma. The full toroidal drift kinetic model is also used to compute the neoclassical toroidal viscous (NTV) torque, yielding results close to that of an analytic model based on geometric simplifications. The computed NTV torque from low-n RMP fields is generally smaller than the resonant electromagnetic torque for this ITER plasma. The linear response computations show a weak core kink response, contrary to a strong kink response often computed for plasmas from present day tokamak devices. Initial value quasi-linear simulations, including various torque models, show a localized damping of the plasma toroidal flow near the edge, as a result of the applied RMP fields. This localized rotation damping can be weak or strong depending on whether a weakly unstable edge localized peeling mode is present. No qualitative difference is found between the n = 3 and n = 4 RMP field configurations, in both the linear and non-linear response results.
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| 9. |
- Ma, Z. R., et al.
(författare)
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NH3-SCR reaction mechanisms of NbOx/Ce0.75Zr0.25O2 catalyst: DRIFTS and kinetics studies
- 2016
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Ingår i: Journal of Molecular Catalysis A: Chemical. - : Elsevier BV. - 1381-1169. ; 423, s. 172-180
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Tidskriftsartikel (refereegranskat)abstract
- A NbOx/Ce0.75Zr0.25O2 (NbCZ) catalyst was synthesized by a citric acid-aided sol-gel method. It shows that above 80% NOx conversion and above 95% N-2 selectivity for the selective catalytic reduction of NOx by ammonia over this catalyst are achieved in the temperature range 200-450 degrees C. Based on the DRIFTS and kinetic studies over NbCZ and Ce0.75Zr0.25O2, the promotion mechanism by niobia loading was elucidated with an overall reaction pathway. Two different reaction routes, "L-H" mechanism via "NH4NO3 + NO" at low temperatures ( 350 degrees C), are presented. The niobia addition increases the surface acidity and promotes the formation of nitrates species at low temperatures. In this way, the reaction between the ads-NH3 and nitrates species is accelerated to form NH4NO3 intermediates, which then decompose to N-2 and H2O. The reaction of the ads-NH3 species with gaseous NOx at high temperatures is also promoted due to the enhanced acidity and weakened thermal stability of nitrates after niobia loading.
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| 10. |
- Martin, P., et al.
(författare)
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Overview of the RFX-mod fusion science programme
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 53:10, s. 104018-
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Forskningsöversikt (refereegranskat)abstract
- This paper reports the highlights of the RFX-mod fusion science programme since the last 2010 IAEA Fusion Energy Conference. The RFX-mod fusion science programme focused on two main goals: exploring the fusion potential of the reversed field pinch (RFP) magnetic configuration and contributing to the solution of key science and technology problems in the roadmap to ITER. Active control of several plasma parameters has been a key tool in this endeavour. New upgrades on the system for active control of magnetohydrodynamic (MHD) stability are underway and will be presented in this paper. Unique among the existing fusion devices, RFX-mod has been operated both as an RFP and as a tokamak. The latter operation has allowed the exploration of edge safety factor q edge < 2 with active control of MHD stability and studies concerning basic energy and flow transport mechanisms. Strong interaction has continued with the stellarator community in particular on the physics of helical states and on three-dimensional codes.
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