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At least 1,477 records · Page 82

The effect of Eu{sup 2+} doping concentration on luminescence properties of Sr{sub 3}B{sub 2}O{sub 6}:Eu{sup 2+} yellow phosphor

Graphical abstract: - Highlights: • The concentration quenching mechanism of Sr{sub 3}B{sub 2}O{sub 6}:Eu{sup 2+}can be interpreted by the dipole–dipole (d–d) interaction of Eu{sup 2+} ions. • The average electronegativity of O{sup 2−} ions located around Eu{sup 2+} ion is 1.9991 eV. • The optimum concentration of Eu{sup 2+} ions in Sr{sub 3}B{sub 2}O{sub 6} is 7 mol%. • Sr{sub 3}B{sub 2}O{sub 6}:Eu{sup 2+} is a hexagonal crystal structure. - Abstract: The Sr{sub 3}B{sub 2}O{sub 6}:Eu{sup 2+} yellow phosphors were synthesized by high-temperature solid state reaction method. The crystal structure and optical properties of the Sr{sub 3}B{sub 2}O{sub 6}:Eu{sup 2+} phosphor was studied. Results indicate that Sr{sub 3}B{sub 2}O{sub 6}:Eu{sup 2+} has a hexagonal crystal structure. The excitation spectrum indicates that this phosphor can be effectively excited by ultraviolet light of near 390 nm and blue light of 460 nm. The emission spectrum shows a intense broad band spectrum peaking at 566 nm, which corresponds to the 4f{sup 6}({sup 7}F)5d ({sup 2}e{sub g})→{sup 8}S{sub 7/2} (4f{sup 7})transition of Eu{sup 2+} ion. The excitation spectrum is a broad asymmetric excitation band extending from 300 nm to 500 nm and the main excitation peak is at 468 nm. The average electronegativity of O{sup 2−} ions located around Eu{sup 2+} ion is 1.9991 eV. The optimum concentration of Eu{sup 2+} is 7 mol%. The concentration quenching mechanism can be interpreted by the dipole–dipole (d–d) interaction of Eu{sup 2+} ions.

36 MATERIALS SCIENCE↗

α-Fe{sub 2}O{sub 3} modified Bi{sub 2}WO{sub 6} flower-like mesostructures with enhanced photocatalytic performance

Graphical abstract: - Highlights: • α-Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6} heterostructures were facilely fabricated by an impregnation method. • The Bi{sub 2}WO{sub 6} matrix was modified by α-Fe{sub 2}O{sub 3} nanoparticles of 10–20 nm on the surface. • The visible-light absorption region of the composite was effectively red-shifted. • The composite exhibited enhanced photocatalytic activity to RhB below Fe-0.4%. • The band gap coupling effect between α-Fe{sub 2}O{sub 3} and Bi{sub 2}WO{sub 6} was interpreted. - Abstract: α-Fe{sub 2}O{sub 3} modified Bi{sub 2}WO{sub 6} mesostructures were facilely prepared by an impregnation method. The characterizations of phase structure, morphology, microstructure, UV–vis absorption, photoluminescence, BET and solar simulated photocatalytic behavior were systematically conducted. The Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6} heterostructure with a Fe mass percentage in 0.05–0.2% presented obviously enhanced photocatalytic activity for the degradation of Rhodamine B than pristine Bi{sub 2}WO{sub 6}. In particular, the apparent reaction rate constant with Fe-0.1% was 2.24-folds of that of pure Bi{sub 2}WO{sub 6}. UV–vis diffuse reflectance spectra showed that the modification of α-Fe{sub 2}O{sub 3} broadened the visible light absorption of Bi{sub 2}WO{sub 6}. The decreased photoluminescence indicated an effective suppression of the recombination of electron–hole pairs at Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6} interface. The band-gap coupling effect between Fe{sub 2}O{sub 3} and Bi{sub 2}WO{sub 6} was interpreted via comparison of relative valence and conductance potentials, which confirmed an irreversible flow of electrons and holes in the interface of Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6}. Moreover, the composite showed excellent circulation stability, suggesting potential application in dealing with environmental pollutions.

36 MATERIALS SCIENCE↗

Reinforcement of double-exchange ferromagnetic coupling by Ru in La{sub 1.24}Sr{sub 1.76}Mn{sub 2-y}Ru{sub y}O{sub 7} manganite system

Highlights: • Effect of Mn-site doping by Ru has been studied in La{sub 1.24}Sr{sub 1.76}Mn{sub 2-y}Ru{sub y}O{sub 7}. • Electrical resistance, magnetoresistance and magnetic properties were measured. • Ru substitution enhances the ferromagnetism and metallicity. • Results were interpreted by the ferromagnetically coupled Ru with Mn ions in Mn–O–Ru network. - Abstract: The effect of Mn-site doping on magnetic and transport properties in the bilayer manganites La{sub 1.24}Sr{sub 1.76}Mn{sub 2-y}Ru{sub y}O{sub 7} (y = 0.0, 0.04, 0.08 and 0.15) has been studied. The undoped compound La{sub 1.24}Sr{sub 1.76}Mn{sub 2}O{sub 7} exhibits a ferromagnetic metal to paramagnetic insulator transition at T{sub C} = 130 K and the substitution of Ru shifts the transition temperatures to higher temperature values. The increased metal–insulator transition by Ru substitution, obtained from temperature dependence of resistivity measurements, indicates that the Ru substitution enhances the metallic state at low temperature regime and favours the Mn–Ru pairs in the Ru doped samples. Moreover, the activation energy values calculated from the temperature dependence of resistivity curves suggest that the Ru substitution weakens the formation of polarons. The increased magnetoresistance ratio from 108% to 136% by Ru substitution, measured at 5 K, points out that the Ru substitution also enhances the inter-grain tunneling magnetoresistance. Thus, the ferromagnetic order and metallic state in La{sub 1.24}Sr{sub 1.76}Mn{sub 2}O{sub 7} system have been enhanced by the presence of Ru in the Mn-site. These reinforcements of ferromagnetic metallic state and magnetoresistance have been interpreted by the ferromagnetically coupled high spin states of Ru with Mn ions in the Mn–O–Ru network.

36 MATERIALS SCIENCE↗

The electron–phonon coupling of fundamental, overtone, and combination modes and its effects on the resonance Raman spectra

Highlights: • The Huang–Rhys factors and electron–phonon coupling constants are calculated. • The changes of overtone mode are larger than those of fundamental mode. • The variation pattern of electron–phonon coupling well interprets the changes of spectra. - Abstract: External field plays a very important role in the interaction between the π-electron transition and atomic vibration of polyenes. It has significant effects on both the Huang–Rhys factor and the electron–phonon coupling. In this paper, the visible absorption and resonance Raman spectra of all-trans-β-carotene are measured in the 345–295 K temperature range and it is found that the changes of the 0–1 and 0–2 vibration bands of the absorption spectra with the temperature lead to the different electron–phonon coupling of fundamental, overtone, and combination modes. The electron-phonon coupling constants of all the modes are calculated and analyzed under different temperatures. The variation law of the electron–phonon coupling with the temperature well interprets the changes of the resonance Raman spectra, such as the shift, intensity and line width of the overtone and combination modes, which are all greater than those of the fundamental modes.

36 MATERIALS SCIENCE↗

Effects of Ho-ion substitution on the magnetic properties of the Ca3Co2O6 frustrated spin-chain compound

Highlights: • A great sensitivity of the Ca{sub 3}Co{sub 2}O{sub 6} magnetic behavior to the presence of magnetic foreign cation are emphasized. • As the Ho content increases the ferrimagnetic configuration becomes less stable; and the antiferromagnetic (AFM) interaction enhances gradually. • Antiferromagnetic coupling interaction between Ho{sup 3+} ions are interpreted, The complex micro-mechanism are discussed in detail. - Abstract: Ho{sup 3+}-ion doped spin-chain compounds Ca{sub 3}Co{sub 2-x}Ho{sub x}O{sub 6} (x = 0, 0.05, 0.1, 0.15) were prepared by a conventional solid-state reaction method. Rietveld refinement of the X-ray diffraction patterns at room temperature confirmed the rhombohedral structure with the R 3-bar c space group. The results reveal that the solid solubility of the Ho element in Ca{sub 3}Co{sub 2}O{sub 6} is in the range of x = 0.1–0.15. Magnetic measurement suggests that with the increased Ho content: (1) the ferromagnetic transition temperature Tc and spin freezing temperature T{sub ƒ} decrease obviously; (2) the ferrimagnetic configuration becomes less stable; (3) the dynamic characteristics become slower; and (4) the antiferromagnetic (AFM) interaction enhances gradually. Based on these phenomena, the mechanism was discussed in detail. The magnetic correlation length is broken at a low Ho{sup 3+}-ion level, and the Ho{sup 3+}-ion pair formation along the chain with a high level of doping was interpreted.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Alternating current conduction mechanisms of RbMgPO4 compound

Highlights: • Two displacive reversible phase transitions located at T{sub 1} = 442/432 K and T{sub 2} = 460/445 K (heating/cooling). • The temperature dependence of conductivity was described in terms of Arrhenius relation. • The ac conductivity of this compound is proportional to ω{sup s} where the s values are between 0 and 2. • The (CBH) model was found to be the appropriate transport mechanism in RbMgPO{sub 4} compound. - Abstract: Rubidium magnesium monophosphate (RbMgPO{sub 4}) compound was prepared from highly pure constituents by solid state reaction. It was characterized by X-ray powder diffraction, IR, Raman, differential scanning calorimetry (DSC) and impedance spectroscopy. The infrared and Raman spectra were interpreted on the basis of PO{sub 4}{sup 3−} vibrations. DSC revealed two displacive and reversible phase transitions at T{sub 1} = 442/432 K and T{sub 2} = 460/445 K (heating/cooling). The electrical conductivity was measured in the frequency and temperature range 200 Hz-5 MHz and 423 K–523 K, respectively. The obtained results were analysed by fitting the experimental data to an equivalent circuit model. The temperature dependence of alternating and direct current conductivities (σ{sub ac}, σ{sub dc}) confirms the observed transitions in the calorimetric study; they were described in terms of Arrhenius relation. The activation energy’s values were determined in each phase. The AC conductivity behavior is ensured by a single process defined as a hopping transport mechanism. The conductivity frequency dependence was interpreted using the correlated barrier-hopping model (CBH) in all phases.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Machine learning-based discovery of molecular descriptors that control polymer gas permeation

While machine learning has found increasing use in predicting the properties of polymeric materials with only a knowledge of chain architecture, determining the molecular factors underpinning properties (“interpretable AI”) has remained less well explored. We show that encoding chain chemistry in commonly employed formats, e.g., binary-valued fingerprints, leads to uniqueness issues during the hashing process to save storage space. This is because the hashing algorithm can map several chemical moieties into the same bit. These issues carry over into the ML algorithms, especially for “inverse” design and interpretable AI, and cannot be avoided by changing the length of the fingerprint. Using MACCS key featurizations of monomer repeats resolves some of these issues, and we show that a few substructures consistently appear in top features for maximizing permeability across several gases and ML models. These are carbon–carbon double bonds (as in polyacetylenes) especially when they are associated with methyl groups (found in branching architectures). Here these results, derived from the limited data set of ~ 500 polymers with experimental gas permeation data, are in agreement with physical insight and thus provide a robust foundation which could further enable study of these material classes through detailed experiments and simulations.

36 MATERIALS SCIENCE↗

Decomposition of liquid-liquid extraction organic phase structure into critical and pre-peak contributions

Solution nanostructure induced by amphiphile self-association plays an important role in various chemical and physical processes, including liquid-liquid extraction (LLE). Small angle scattering techniques are an essential means of probing this structure, but, due to non-uniqueness of scattering patterns, their interpretation is not trivial. Here, in this study, we decompose small angle x-ray scattering (SAXS) patterns for a range of binary LLE organic phases into two components: Ornstein-Zernike and pre-peak contributions resulting from, respectively, critical concentration fluctuations and packing of the amphiphilic extractant molecules in the nonpolar aliphatic diluent. While we previously applied Ornstein-Zernike scattering models to similar organic phases, including the pre-peak explicitly in the fit allows us to measure weak fluctuations at high extractant concentration and simultaneously obtain information on the position and intensity of the correlation peak related to amphiphile packing. Scattering patterns and partial structure factors calculated from molecular dynamics simulations support this interpretation. We demonstrate how this minimal scattering model describes nanostructuring for a large number of extractant types over their entire extractant/diluent composition ranges, suggesting simple and universal behavior. The straightforward assignment of these structural contributions facilitates the comparison of these features between different classes of extractant molecules and will enable further studies of organic phase aggregation. Applicability to more complex, process-relevant organic phases is illustrated with post-contact organic phases containing significant quantities of extracted lanthanide nitrate salt, which we find are readily described by this model.

74 ATOMIC AND MOLECULAR PHYSICS↗

Resolving protein-mineral interfacial interactions during in vitro mineralization by atom probe tomography

Organic macromolecules exert remarkable control over the nucleation and growth of inorganic crystallites during (bio)mineralization, as exemplified during enamel formation where the protein amelogenin regulates the formation of hydroxyapatite (HAP). However, it is poorly understood how fundamental processes at the organic-inorganic interface, such as protein adsorption and/or incorporation into minerals, regulates nucleation and crystal growth due to technical challenges in observing and characterizing mineral-bound organics at high-resolution. Here, atom probe tomography techniques were developed and applied to characterize amelogenin-mineralized HAP particles in vitro, revealing distinct organic-inorganic interfacial structures and processes at the nanoscale. Specifically, visualization of amelogenin across the mineralized particulate demonstrates protein can become entrapped during HAP crystal aggregation and fusion. Identification of protein signatures and structural interpretations were further supported by standards analyses, i.e., defined HAP surfaces with and without amelogenin adsorbed. These findings represent a significant advance in the characterization of interfacial structures and, more so, interpretation of fundamental organic-inorganic processes and mechanisms influencing crystal growth. Ultimately, this approach can be broadly applied to inform how potentially unique and diverse organic-inorganic interactions at different stages regulates the growth and evolution of various biominerals.

36 MATERIALS SCIENCE↗

Exploring the Impact of Nuclear Data Uncertainties in Ultra-high Resolution Gamma Spectroscopy for Isotopic Analysis Using Approximate Bayesian Computation

High purity germanium (HPGe) currently provides the highest readily available resolution gamma detection for a broad range of radiation measurements, but microcalorimetry is a developing option that has considerably higher resolution even than HPGe. Superior microcalorimetry resolution offers the potential to better distinguish closely spaced X-rays and gamma-rays, a common challenge for the low energy spectral region near 100 keV from special nuclear materials, and the higher signal-to-background ratio also confers an advantage in detection limit. As microcalorimetry continues to develop, it is timely to assess the impact of uncertainties in detector and item response functions and in basic nuclear data, such as branching ratios and half-lives, used to interpret spectra in terms of the contributory radioactive isotopes. We illustrate that a new inference option known as approximate Bayesian computation (ABC) is effective and convenient both for isotopic inference and for uncertainty quantification for microcalorimetry. The ABC approach opens a pathway to new and more powerful implementations for practical applications than currently available.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Reliable statistics-based detection and investigation of anomalies in a SMART valve system

Reliable anomaly detection and diagnosis are critical for the safe operation of complex engineered systems. This study presents a unified framework that integrates statistical, model-based, and data-driven techniques for anomaly detection and investigation, demonstrated on SMART valve systems in hybrid energy applications. Four detection methods—mean deviation, seasonal extreme studentized deviate, ARIMA forecasting, and matrix profiling—were implemented and compared. Matrix profiling was particularly effective in revealing subtle deviations and hidden relationships among variables. Anomaly investigation was performed by analyzing variable-level and grouped signal profiles, with system topology incorporated to distinguish primary faults from propagated effects. Grouping signals by type enhanced interpretability, enabling accurate localization of anomalies across multi-dimensional datasets. Experimental results confirmed the framework's capability to consistently detect and isolate anomalies while providing actionable insights into system interdependencies. The proposed methodology offers a robust, interpretable, and scalable solution for condition monitoring, with potential applications in safety-critical domains such as nuclear energy, aerospace, and process industries.

ARIMA models↗

HACC: Simulating sky surveys on state-of-the-art supercomputing architectures

Current and future surveys of large-scale cosmic structure are associated with a massive and complex datastream to study, characterize, and ultimately understand the physics behind the two major components of the ‘Dark Universe’, dark energy and dark matter. In addition, the surveys also probe primordial perturbations and carry out fundamental measurements, such as determining the sum of neutrino masses. Large-scale simulations of structure formation in the Universe play a critical role in the interpretation of the data and extraction of the physics of interest. Just as survey instruments continue to grow in size and complexity, so do the supercomputers that enable these simulations. In this paper, we report on HACC (Hardware/Hybrid Accelerated Cosmology Code), a recently developed and evolving cosmology N-body code framework, designed to run efficiently on diverse computing architectures and to scale to millions of cores and beyond. HACC can run on all current supercomputer architectures and supports a variety of programming models and algorithms. It has been demonstrated at scale on Cell- and GPU-accelerated systems, standard multi-core node clusters, and Blue Gene systems. HACC’s design allows for ease of portability, and at the same time, high levels of sustained performance on the fastest supercomputers available. We present a description of the design philosophy of HACC, the underlying algorithms and code structure, and outline implementation details for several specific architectures. We show selected accuracy and performance results from some of the largest high resolution cosmological simulations so far performed, including benchmarks evolving more than 3.6 trillion particles.

79 ASTRONOMY AND ASTROPHYSICS↗

Ultrafast radiographic imaging and tracking: An overview of instruments, methods, data, and applications

Ultrafast radiographic imaging and tracking (U-RadIT) use state-of-the-art ionizing particle and light sources to experimentally study sub-nanosecond transients or dynamic processes in physics, chemistry, biology, geology, materials science and other fields. These processes are fundamental to modern technologies and applications, such as nuclear fusion energy, advanced manufacturing, communication, and green transportation, which often involve one mole or more atoms and elementary particles, and thus are challenging to compute by using the first principles of quantum physics or other forward models. One of the central problems in U-RadIT is to optimize information yield through, e.g. high-luminosity X-ray and particle sources, efficient imaging and tracking detectors, novel methods to collect data, and large-bandwidth online and offline data processing, regulated by the underlying physics, statistics, and computing power. We review and highlight recent progress in: (a.) Detectors such as high-speed complementary metal-oxide semiconductor (CMOS) cameras, hybrid pixelated array detectors integrated with Timepix4 and other application-specific integrated circuits (ASICs), and digital photon detectors; (b.) U-RadIT modalities such as dynamic phase contrast imaging, dynamic diffractive imaging, and four-dimensional (4D) particle tracking; (c.) U-RadIT data and algorithms such as neural networks and machine learning, and (d.) Applications in ultrafast dynamic material science using XFELs, synchrotrons and laser-driven sources. Hardware-centric approaches to U-RadIT optimization are constrained by detector material properties, low signal-to-noise ratio, high cost and long development cycles of critical hardware components such as ASICs. Interpretation of experimental data, including comparisons with forward models, is frequently hindered by sparse measurements, model and measurement uncertainties, and noise. Alternatively, U-RadIT make increasing use of data science and machine learning algorithms, including experimental implementations of compressed sensing. Machine learning and artificial intelligence approaches, refined by physics and materials information, may also contribute significantly to data interpretation, uncertainty quantification and U-RadIT optimization.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Meso-scale modeling of irradiated concrete in test reactor

In this paper, we detail a numerical model accounting for the effects of neutron irradiation on concrete at the mesoscale. Irradiation experiments in test reactor (Elleuch et al.,1972), i.e., in accelerated conditions, are simulated. Concrete is considered as a two-phase material made of elastic inclusions (aggregate) subjected to thermal and irradiation-induced swelling and embedded in a cementitious matrix subjected to shrinkage and thermal expansion. The role of the hardened cement paste in the post-peak regime (brittle-ductile transition with decreasing loading rate), and creep effects are investigated. Radiation-induced volumetric expansion (RIVE) of the aggregate cause the development and propagation of damage around the aggregate which further develops in bridging cracks across the hardened cement paste between the individual aggregate particles. The development of damage is aggravated when shrinkage occurs simultaneously with RIVE during the irradiation experiment. The post-irradiation expansion derived from the simulation is well correlated with the experimental data and, the obtained damage levels are fully consistent with previous estimations based on a micromechanical interpretation of the experimental post-irradiation elastic properties (Le Pape et al.,2015). In conclusion, the proposed modeling opens new perspectives for the interpretation of test reactor experiments in regards to the actual operation of light water reactors.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

On the flow induced vibration of an externally excited nuclear reactor experiment

An in-pile, drop-in experiment design is presently being designed and studied for the near-term deployment within the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL); this experiment is termed the Miniplate-1 Large-B (MP-1 LB) Experiment. A number of explicit studies are performed during the design- and safety-related stage. Traditionally, a clear and logical methodology has been developed and utilized for analyses such as hydraulics, thermal-loads, mechanical loads, and others for these experiments. Recently a small component from a different experiment assembly mechanically separated while in the reactor’s core. While this experiment didn’t compromise the safety of the reactor, it led to a higher-level question which centered on whether the appropriate level of consideration was being made toward the fluid–structure-interactions of these experiments. The outcome yielded separate flow test experiments of like-for-like geometry in an experimental loop located at Oregon State University which produces experimental data compliant with applicable parts and requirements to ASME’s NQA-1 2008, 2009a standard – suitable for benchmark evaluation. Here, the objectives of this study are to (1) develop a process for handling and interpreting the mechanical response of the test elements during hydraulic testing, to (2) characterize the motion of a specific test element during a flow test which imposes a wide range of hydraulic conditions, and (3) provide objective observations toward the potential safety related implications that are tied to the synthesized data. The outcome of this study has led to a confident process in inspecting the experimental data, synthesized it for interpretation, identified several unique hydraulic characteristics of the experiment design which were previously unknown, and demonstrated that the likelihood for mechanical failure resulting from fluid-structure-interactions in the reactor is far below any criterion for concern of the element’s safety.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

A methodology for decay heat characterization in molten salt reactors

Accurate decay heat prediction in molten salt reactors (MSRs) faces dual challenges: complex operational uncertainties and the need for interpretable models compatible with engineering workflows. This work presents a hybrid machine learning and segmented polynomial methodology that addresses both requirements through three key innovations. First, a modular data architecture encodes MSR-specific operational parameters (power density: 1-100 W cm -3 , humidity: 0-0.1 wt %, air ingress: 0-0.1 mol %) with uncertainty-aware temporal discretization spanning 15 orders of magnitude. Second, region-optimized machine learning models achieve 92.3 % root mean square error (RMSE) reduction over conventional polynomials while maintaining physical interpretability through automated piecewise equation generation. Third, dual front-end interfaces accelerate safety analyses — a Jupyter environment enables researchers to explore 10,000+ parameter combinations via interactive widgets, while a Streamlit web application reduces design iteration cycles through production-grade visualization tools. Operational deployment demonstrates prediction times of only a couple hundred milliseconds for 10 4 years decay profiles, enabling real-time optimization of spent fuel container designs.

42 - ENGINEERING↗

New insights into the nuclear structure in neutron-rich 112,114,115,116,117,118Pd

New level schemes of 112,114,115,116,117,118Pd are established by means of ?–?–??–?–?, ?–?–?–??–?–?–? and ?–?(0)?–?(0) measurements of prompt fission y rays from 252Cf using the Gammasphere multi-detector array. Spins/parities were assigned to levels based on ?–??–? angular correlation measurements, level systematics and decay patterns. In the even-N isotopes 112,114,116Pd, two sets of odd-parity bands were identified and extended with spins measured in each band. The odd-parity bands with large level staggerings were interpreted as disturbed chirality with less pronounced triaxial deformations in the Pd isotopes than observed in the chiral symmetry breaking 110,112Ru with maximum triaxiality. Onset of wobbling motion was identified from the sign of the signature splitting in the ? band of even–even 114Pd, and probably also in 116Pd, as first seen in the N=68N=68 isotone 112Ru. Maximal triaxiality in Ru and Pd isotopes is found to be reached for N=68N=68, 112Ru and 114Pd, 4 neutrons more than predicted in the theoretical calculations. The new data and TRS calculations allowed a systematic study of the band crossings in the even-N112,114,116Pd and odd-N115,117Pd isotopes. Now we find a new overall, more complex shape evolution than previously proposed from triaxial prolate in 110Pd via triaxial oblate in 112Pd to nearly oblate in 114,116Pd with a large change of the triaxial deformation parameter y toward nearly oblate in the (pi g 9/2)2 alignment in 114,115,116,117,118Pd, and triaxial-prolate–triaxial-oblate shape coexisting bands in 115Pd.

112,114,115,116,117,118Pd↗

Ultraperipheral Collisions at RHIC and the LHC

The current status of ultraperipheral measurements in heavy ion collisions is discussed, with an emphasis on what is learned from one photon (photonuclear) and two photon (γ+γ) processes. Furthermore, the interpretation of recent data on “nonUPC” events, in which electromagnetic processes occur simultaneously with hadronic ones, is also discussed. Results from the LHC (ALICE, ATLAS, CMS, and LHCb) and the STAR experiment at RHIC are discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗