Advanced Science Research Center

In this paper, several optimized design results of the HTGR-based 10 MWth Reaktor Daya Eksperimental (RDE) (Experimental Power Reactor), so far conducted, are reviewed and compared from the neutronics, reactor types, refueling schemes, and fuel cycle points of view. The review covers the multipass and once-through-then-out (OTTO) pebble-bed cores, as well as block/prismatic type cores with several fuel shuffling options. As for the fuel cycle, uranium and thorium fuels are considered. The fuel burnup performance and power distribution are evaluated and compared among other important design parameters. Reactor physics codes, nuclear data libraries, and calculation models and procedures used for the design and analysis are reviewed, and challenges for future improvements are discussed.

We report atomic mass measurements of the unstable nuclides 73−75 Ni, 73−78 Cu, and 74−78 Zn, which have been accomplished using multi-reflection time-of-flight mass spectrometry combined with new technical developments to resolve challenges for exotic-isotope identification and selection. The isotopes were produced in-flight at the RIKEN’s Radioactive Ion Beam Facility and delivered to the combined gas cell and multi-reflection system installed downstream of the ZeroDegree spectrometer. The incoming high-energy beam was energy-degraded and subsequently stopped in a helium gas cell. The energy degrader thickness was optimized using a new method that employs signals from plastic scintillators located upstream and downstream of the helium-filled gas cell. Extracted isotopes of interest were mass-selected by the in-MRTOF deflector method, for which we discuss simultaneous selection of multiple isobar chains. The ions of interest were identified unambiguously using β-decay-correlated mass measurements for the first time, which is demonstrated for 78 Zn. The new mass values are compared with literature values and recent measurements performed at JYFLTRAP and ISOLTRAP, where a generally good agreement is observed.

In this work, we analyze the energy density and the stress distribution inside the pion derived from gravitational form factors in top-down holographic QCD. In particular, we show that the dominance of the scale anomaly in the confining pressure, previously observed in the instant form for the nucleon, also holds for the pion in the light-front form. Furthermore, we find that in large- <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msub> <a:mi>N</a:mi> <a:mi>c</a:mi> </a:msub> </a:math> QCD described by this approach, the scalar glueball plays a mediating role in transmitting the confining pressure. These findings support the universal role of the scale anomaly in the stability of hadrons.

Abstract This study aims to investigate the temperature-dependent structure of germanene prepared by atomic segregation epitaxy on an Ag(111) thin film surface. A germanene (7√7 × 7√7) superstructure, obtained upon heating at 500 °C followed by cooling at room temperature, transforms into a germanene (√109 × √109) superstructure after further annealing at 250 °C and subsequently evolves into the Ag–Ge surface alloy upon annealing at 350 °C, as evidenced from the thorough analysis by scanning tunneling microscopy, low-energy electron diffraction, and core-level (CL) photoemission spectroscopy. Angle-resolved CL spectra reveal that germanium preferentially occupies the topmost atomic layer, forming the (7√7 × 7√7) and (√109 × √109) superstructures. In contrast, germanium is distributed within at least a few layers for the striped incommensurate surface alloy phase. From angle-resolved photoemission spectroscopy, the electronic structures of the (7√7 × 7√7) and (√109 × √109) superstructures appear to be almost the same. Based on these considerations, the surface phase diagram of Ge/Ag(111)/Ge(111) has been constructed. These findings provide insights into the relationship between germanene thermal stability and Ge concentration at the surface region of Ag(111).

Recent measurements of J/ψ production as a function of event charged-particle multiplicity at the collision energies of both the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC) show enhanced J/ψ production yields with increasing multiplicity. One potential explanation for this type of dependence is multiparton interactions (MPI). We present the first study of potential autocorrelations at RHIC energies and forward and backward rapidity of self-normalized J/ψ yields and ψ(2S) to J/ψ ratio, as a function of self-normalized multiplicity in p+p collisions. In addition, detailed studies tuned to RHIC energies were performed to investigate the MPI impacts. We find that the PHENIX data at RHIC are consistent with recent LHC measurements and can only be described by calculations that include MPI effects. The forward and backward ψ(2S) to J/ψ ratio is found to be less dependent on the charged-particle multiplicity.

International audience

The corner problem is a century-old canonical scattering problem describing wave diffraction at a quarter-plane spatial discontinuity. Here, we study its space-time analog: wave scattering at a corner in space-time, arising at a time-switched spatial interface. We highlight and resolve an inconsistency between spatial and temporal boundary conditions arising in this problem, and analytically demonstrate the emergence of shock waves launched by the scattering process. After numerically verifying our theory, we realize and experimentally probe the scattering at a space-time corner arising at the edge of a time-switched waveguide. Our results unveil and efficiently model the unusual phenomena arising at the spatial interface between time-modulated and static media, of great relevance for the growing field of spatiotemporal metamaterials.

A Magnetic Rotational (MR) band in 57 Fe nucleus has been newly identified and established from the decreasing behaviour of the experimental electric dipole transition probabilities, B(M1), determined from the measured lifetimes of the states. This becomes the first nucleus in the lighter mass ( A < 60 ) region in which, the B(M1) values of an MR band are measured. A single-particle configuration of π f 7 / 2 − 2 ⊗ ν ( p 3 / 2 f 5 / 2 p 1 / 2 ) 3 has been assigned to this MR band. This configuration, which involves only the negative parity proton and neutron orbitals below and above the Z,N = 28 shell closures, respectively, is a unique one which was not identified before for a MR band. The range of observed angular momenta for this band is congruent with this configuration and the experimental data are found to be in agreement with the SPAC (Shears mechanism with Principal Axis Cranking) and semi-classical calculations. Shell model calculations with GXPF1A interaction reproduce the observed levels in 57 Fe including the band head of the MR band. This validates the assigned configurations of this band.

Inflammatory pain is a worldwide health problem, affecting primarily women. Nonetheless, most research conducted in this field has involved male subjects, and only 10% of the results have been obtained using females. Gold Lotion (GL) is a formulated product made from the peels of six citrus fruits that have been proven, via experimental data, to possess several biological properties, such as anti-inflammatory, anticancer, and antibacterial activities. This research aims to investigate the response to GL administration in two models of peripheral inflammation to assess potential sex differences. Carrageenan was used to induce mechanical allodynia and maximal edema within hours, serving as a model of acute inflammation, while Complete Freund's Adjuvant (CFA) was used to obtain similar results within days, resulting in a model of chronic inflammation. Acute GL administration reduced mechanical allodynia in both models and both sexes, with no anti-inflammatory effects observed. In conclusion, this study demonstrates the potential of GL to alleviate inflammatory pain in both males and females, thereby broadening its therapeutic applications.