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Focused Very-High Energy Electron (VHEE, 50–300 MeV) and Ultra-High Energy Electron (UHEE, > 300 MeV) beams can accurately target both large and deeply seated human tumors with high sparing properties, while avoiding the spatial requirements and cost of proton and heavy ion facilities. Advanced testing phases are underway at the CLEAR facilities at CERN (Switzerland), NLCTA at Stanford (USA), and SPARC at INFN (Italy), aiming to accelerate the transition to clinical application. Currently, Monte Carlo (MC) transport is the sole paradigm supporting preclinical trials and imminent clinical deployment. In this paper, we propose an alternative: the first extension of the nuclear-reactor deterministic chain Njoy-Dragon for VHEE and UHEE applications. We have extended the Boltzmann-Fokker-Planck (BFP) multigroup formalism and validated it using standard radio-oncology benchmarks, complex assemblies with a wide range of atomic numbers, and comprehensive irradiation of the entire periodic table. We report that 99 % of water voxels exhibit a BFP-MC deviation below 2 % for electron energies under 1.5 GeV . Additionally, we demonstrate that at least 97 % of voxels of bone, lung, adipose tissue, muscle, soft tissue, tumor, steel, and aluminum meet the same criterion between 50 MeV and 1.5 GeV . For water, the thorax, and the breast intra-operative benchmark, typical average BFP-MC deviations of 0.3 % and 0.4 % were observed at 300 MeV and 1 GeV , respectively. By irradiating the entire periodic table, we observed similar performance between lithium ( Z = 3 ) and cerium ( Z = 58 ). Deficiencies observed between praseodymium ( Z = 59 ) and einsteinium ( Z = 99 ) have been reported, analyzed, and quantified, offering critical insights for the ongoing development of the Evaluated Nuclear Data File mode in Njoy. [ABSTRACT FROM AUTHOR]

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) is the world's largest and most powerful particle accelerator colliding beams of protons and lead ions at energies up to 7 Z TeV, where Z is the atomic number. ALICE is one of the experiments optimised for heavy-ion collisions. A fixed-target experiment in ALICE is being considered to collide a portion of the beam halo, split using a bent crystal inserted in the transverse hierarchy of the LHC collimation system, with an internal target placed a few metres upstream of the existing detector. This study is carried out as a part of the Physics Beyond Collider effort at CERN. Fixed-target collisions offer many physics opportunities related to hadronic matter and the quark-gluon plasma to extend the research potential of the CERN accelerator complex. Production of physics events depends on the particle flux on the target. The machine layout for the fixed-target experiment is developed to provide a flux of particles on the target high enough to exploit the full capabilities of the ALICE detector acquisition system. This paper summarises the fixed-target layout consisting of the crystal assembly, the target and the downstream absorbers. We discuss the conceptual integration of these elements within the LHC ring, the impact on ring losses, and expected performance in terms of particle flux on target. [ABSTRACT FROM AUTHOR]

In this paper, a pioneering study of the electronic and optical properties of QPHT-graphene after adsorbing three types of alkali metal atoms (Li/Na/K) was conducted using first-principles calculations based on density functional theory. The electronic properties study covers TDOS, PDOS, and Bader charge analyses, in addition to charge density difference. The optical properties study considers the complex dielectric function, complex refractive function, absorption coefficient, reflection coefficient and energy loss function under three types of polarization. The results show that all configurations exhibit a good optical response within a wide energy range of 0–25 eV and are anisotropic under all three polarization types. Under E x and E y polarizations, the adsorption of alkali metal atoms significantly enhances the absorptivity, reflectivity, and refractivity of the pristine QPHT-graphene. As the atomic number increases, it shows a regular oscillatory behavior. Under E z polarization, the QPHT-graphene optical response is concentrated in the high-frequency ultraviolet region, i.e., higher than 10 eV, and alkali metal atom adsorption has little effect on its optical properties. These results show that alkali metal atom adsorption can effectively modulate the optical properties of QPHT-graphene. This research can help to further understand the electronic and optical properties of QPHT-graphene and is instructive in promoting the application of new two-dimensional nanocarbon materials in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

The interaction of nickel(II) with halogenazomercaptophenols (HAMPs) {1-(5-bromo-2-pyridylazo)-2-hydroxy-4-mercaptophenol and 1-(5-iodo-2-pyridylazo)-2-hydroxy-4-mercaptophenol} in the presence of aminophenols (APs) 2,6-bis(N,N-dimethylaminomethyl)-4-methylphenol and 2,6-bis(N,N-dimethylaminomethyl)-4-ethylphenol was studied by the extraction-photometric method. The charge of the resultant complexes was determined by the methods of ion electromigration and electrophoresis on paper. Colored complexes proved to be anions. Upon introduction of the aminophenols into the system the anionic complexes passed into the organic phase in the form of mixed-ligand complexes (MLCs). A single extraction with chloroform provided a 97.1–98.9% yield of nickel(II) in the form of an MLC. The optimal range of acidity of the medium, corresponding to a maximal and constant absorbance, was pHopt 2.4–6.5 (рHform 0.7–8.4). The maximum absorbance was reached within 8–12 min. The optimal condition for the formation and extraction of these compounds were identified as HAMP concentration of (1.12–2.34)×10–3 M and the AP concentration of (6.3–8.4)×10–4 M. A 20-fold increase in the volume ratio of the aqueous to organic phase did not affect the completeness of the extraction. Light absorption was at a maximum at 605–648 nm. In the composition of the MLCs, there was one mole of HAMP and AP each per mole of nickel. Using the Nazarenko method, it was found that Ni2+ is the complexing form of nickel. The number of protons it displaced from one H2L molecule turned out to be equal to 2. The performed calculations showed that the MLCs do not polymerize in the organic phase and occur in the monomeric form (γ = 0.94–1.07). The results of studies on the formation and extraction of MLCs of Ni(II) with HAMP and AP and the physicochemical and analytical characteristics of these compounds served as a basis for the development of new techniques for the extraction-photometric determination of Ni(II) in wastewater, bottom sediments, crude oil, and petroleum products of Baku. [ABSTRACT FROM AUTHOR]

In this paper we investigate the impact of the higher-twist effects, resummed by the non-linear approaches for the QCD dynamics, on the inclusive observables that will be measured in future electron-ion colliders. We assume a phenomenological model for the dipole-nucleus scattering amplitude which takes into account the non-linear corrections and estimate the contribution of the different twists for F 2 A (x , Q 2) , F L A (x , Q 2) and ∂ F 2 A / ∂ l n Q 2 considering different values of the Bjorken-x variable, photon virtuality Q 2 and atomic number A. A comparison with the full predictions is performed and the impact of the distinct twists is estimated. Our results indicate that a future analysis of the logarithmic Q 2 slope and longitudinal structure function will allow us to probe the presence of the non-linear effects on the QCD dynamics. [ABSTRACT FROM AUTHOR]

Radiation induces deterioration to life, the environment and electronic gadgets. Also, the escalating quests in use of radioactive entities has induced increased radioactive hazards resulting in the need to fabricate advanced materials for efficient protection against the deteriorating effects of radiation. Inclusive of differing techniques to achieve radiation attenuation, the use of compounds exhibiting elevated atomic number (Z), including lead, has been attained. On the other hand, lead exhibit toxicity. Therefore, varying researches have investigated the use of minimally-toxic post-transitionally metallic-oriented compounds, such as bismuth. However, polymeric materials offer great prospects attributable to their inherent electrical, mechanical, thermal, as well as multi-functional dispositions. However, composites fabricated from polymers with elevated atomic number reinforcements facilitate attainment of materials exhibiting minimal weight, good flexibility, and exceptional processability. Therefore, this paper elucidates emerging advancements in synthesization of polymeric materials and nanoarchitectures for radiation protection, focusing on application of polymeric nanoarchitectures for attenuation of varying forms of radiation. [ABSTRACT FROM AUTHOR]

This paper presents a multi-scale numerical method to study the electrolyte material BaZrO3 (BZO) and gives numerical implementations and results. At the microscopic level, molecular dynamics (MD) is used to model the atomic structure of BZO. At the macroscopic level, the finite element method is used for loading and numerical solution. To bridge the microscopic and macroscopic scales, the concept of coarse-grained and coupled algorithms was used to establish a relationship between the atomic mass and the number of nodes in a continuous medium by means of a weighted residual method. This approach takes into account the anisotropy of the atomic structure of BZO and determines an intrinsic nature law through detailed modelling of the microstructure. We first describe the principle of the Atom-to-Continuum (AtC) multiscale approach and verify the accuracy of the multiscale calculation method by comparing the stress–strain curves of BZO with a central crack under the AtC method and MD simulations. The mechanical response of the crack under macroscopic and microscopic calculations is then observed and discussed by combining it with finite element software. Under the finite element simulations, the crack extends forward in a cleavage manner, while in the MD simulations the results show a clear directional dependence: the (100) surface fracture involves in-plane slip, with the crack propagating forward perpendicular to the plane between Zr and O; in the (110) surface the crack is unstable as it extends, resulting in a zigzag crack extension path, with the final crack remaining in the same direction as the initial direction remains the same. Our study not only reveals the fracture mechanism of perovskite oxide BZO but also presents a multi-scale approach that allows for large-scale calculations, providing a new way of studying the material design and applications. [ABSTRACT FROM AUTHOR]

The ongoing paper describes the neutron–gamma photon efficiency of two vinyl ester composites utilizing MCNPX Monte Carlo Simulation Code (MCSC), analytical calculations, and newly developed Phy-X: PSD software. The colemanite and barite vinyl ester composites were irradiated by 252Cf radio isotopic source. In this study, new methods, namely Watt Fission Distribution (WFD) and Doppler Effect (DE), are used to extract the neutron–gamma photon spectra for vinyl ester series. Fast Neutron Removal Cross Section (FNRCS) and other related neutron attenuation features are derived by analytical calculations. The analytical results reveal that the increasing rate of barite in vinyl ester series rises the fast neutron shielding capacity of the sample from 4.722 to 7.117 cm−1, while a descending trend of 9.905 cm−1 to 9.572 cm−1 is found for the colemanite vinyl ester series. Moreover, the gamma photon Linear Attenuation Coefficient (LAC) is extracted via MCNPX simulation. Accordingly, increasing order of (LAC)V-C0% < (LAC)V-C20% < (LAC)V-C50% < (LAC)V-B0% < (LAC)V-B20% < (LAC)V-B50% is reported for the colemanite and barite vinyl ester series. The effective atomic number (Zeff) experiences a sharp peak for barite vinyl ester composites which may be due to the K-edge absorption of high Z element resources. From the obtained results, it can be deduced that V-C0% has the best neutron shielding performance, while V-B50% possesses the highest shielding capacity against gamma photon among the rest of the colemanite- and barite-containing resources. These results could be highly beneficial for further investigation in different fields of study. [ABSTRACT FROM AUTHOR]

This paper demonstrates how secondary electron energy spectroscopy (SEES) performed inside a scanning electron microscope (SEM) can be used to map sample atomic number and acquire bulk valence band density of states (DOS) information at low primary beam voltages. The technique uses an electron energy analyser attachment to detect small changes in the shape of the scattered secondary electron (SE) spectrum and extract out fine structure features from it. Close agreement between experimental and theoretical bulk valance band DOS distributions was obtained for six different test samples, where the normalised root mean square deviation ranged from 2.7 to 6.7%. High accuracy levels of this kind do not appear to have been reported before. The results presented in this paper point towards SEES becoming a quantitative material analysis companion tool for low voltage scanning electron microscopy (LVSEM) and providing new applications for Scanning Auger Microscopy (SAM) instruments. [ABSTRACT FROM AUTHOR]

We re-examine the history of the element "nipponium" discovered by a Japanese chemist Masataka Ogawa in 1908. Since 1996 H.K. Yoshihara has made extensive research into Ogawa's work and revealed evidence that nipponium proposed for the place of the atomic number of 43 was actually rhenium (75). In this paper, we provide critical re-interpretations of the existing information and confirmed that Ogawa left indisputable evidence that nipponium was in fact rhenium. We further discuss the reasons for the existing doubts and criticism against Ogawa's discovery and Yoshihara's interpretation, and attempt to resolve them. [ABSTRACT FROM AUTHOR]

The paper shows that the values of zero-point energy and vibrations of atoms in a crystal determined by the uncertainty principle, depend on the dynamic response of atoms. It is found that the root-mean-square (rms) amplitude of thermal and zero-point vibrations of atoms in crystal lattices of elements from the periodic table, has a periodic dependence on the atomic number of elements. It is shown that the rms amplitude of thermal vibrations of atoms in crystal lattices of elements with high Debye temperature, does not strongly differ from their zero-point vibrations at room temperature. This is explained by a small number of excited vibrations with the maximum frequency at room temperature, since the latter is significantly lower than their Debye temperature, at which the whole range of thermal vibrations of atoms in the crystal excites. The obtained results can be used in materials science and technology to estimate the strength and thermal characteristics of materials at cryogenic temperatures, without their direct measurements at the absolute-zero temperature. [ABSTRACT FROM AUTHOR]

In this paper, we report on the Boltzmann kinetic equation approach adapted for simulations of warm dense matter created by irradiation of bulk gold with intense ultrashort X-ray pulses. X-rays can excite inner-shell electrons, which triggers creation of deep-lying core holes. Their relaxation, especially in heavier elements such as gold (atomic number Z = 79 ) takes complicated pathways, involving collisional processes, and leading through a large number of active configurations. This number can be so high that solving a set of evolution equations for each configuration becomes computationally inefficient, and another modeling approach should be used instead. Here, we use the earlier introduced 'predominant excitation and relaxation path' approach. It still uses true atomic configurations but limits their number by restricting material relaxation to a selected set of predominant pathways for material excitation and relaxation. With that, we obtain time-resolved predictions for excitation and relaxation in X-ray irradiated bulk of gold, including the respective change of gold optical properties. We compare the predictions with the available data from high-energy-density experiments. Their good agreement indicates ability of the Boltzmann kinetic equation approach to describe warm dense matter created from high-Z materials after their irradiation with X rays, which can be validated in future experiments. [ABSTRACT FROM AUTHOR]

Studies of bioactive glasses give an advanced roadbook to realize radiation applications in nuclear medicine and other medical applications. This paper aims to investigate the gamma ray interaction parameters of the PbCl2–SnCl2–P2O5 glass system. The mass attenuation coefficients (μm) of the selected bioactive glasses have been obtained using XCOM and dosimetry Phy-X/PSD programs in the photon energy range 10–150 keV and also correlated with those simulated through MCNP5 code. The other parameters, such as the effective atomic number (Zeff), electron density (Ne), and mean free path (MFP), tenth-value layer (TVL), and half-value layer (HVL) values have also been computed. Among all the selected bioactive glasses, the S4 bioactive glass has the lowest MFP, HVL, and TVL, showing that it is highly effective in absorbing gamma rays. The values of MFP of all samples (S1–S8) are also compared to the RS 253G18 and RS 360 commercial glasses at energy 150 keV. The fast neutron removal cross-sections have been obtained to study the fast neutron absorption behavior with the selected bioactive glasses. [ABSTRACT FROM AUTHOR]

The current paper studied the (95-y)P2O5–yBi2O3–5Nb2O5 glass systems where y = 10, 12.5, 15, and 17.5 mol% using EPICS2017 data library to understand the radiation shielding characteristics. The investigated glass systems, PNbBi1 to PNbBi4, were evaluated in terms of linear attenuation coefficient (LAC), mass attenuation coefficient (MAC), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), and effective atomic numbers (Zeff) at the energy levels of 20, 40, 60, 80, and 100 keV. According to the theoretical computations, Bi2O3 ensured to improve LAC parameter in all photon energies; hence, PNbBi4 can be regarded as the best. Further, we reported that a nearly 14% increase in glass density leads to improve MAC parameters against ascending photon energies. PNbBi4 can be regarded as the lowest thickness ensuring sample at all photon energies amongst the other samples with respect to HVL and TVL parameters. Moreover, inserting Bi2O3 provided lower MFP thicknesses which in turn develops better radiation shielding characteristics. We found out that Zeff shows an increasing trend as the Bi2O3 increases, but displays a decreasing trend as the photon energy increases. Additionally, a comparison of shielding properties using the EpiXS and Phy-X/PSD has been evaluated. It was figured out that there is a good agreement observed between the results of each library. The results in most energies were found to be in good agreement with low (< 1%) relative differences. Overall, the authors concluded that the Bi2O3-reinforced PNb series can be utilized in X-ray shielding applications with satisfactory performance. [ABSTRACT FROM AUTHOR]

The processes of erosion and redeposition of plasma-facing materials in fusion devices are some of the most important factors affecting the plasma parameters and the resource of the first wall. The method of analyzing thin layers on a surface using keV-energy proton scattering expands the functionality of determining the rate of erosion and deposition of layers with a large atomic number on a substrate of a light element or, conversely, light layers on a heavy substrate, which is typical of modern fusion installations. The analysis of deposition and/or erosion consists in placing special marker targets with the layers of a material with a low atomic number and/or material with a large atomic number in the places of the installation in which it is proposed to study the rate of erosion and/or deposition, with a subsequent analysis of the energy spectra of hydrogen ions reflected from exposed targets with energies in the kiloelectron-volt range. In this paper, estimates of the applicability of this technique directly in a fusion device with regard to the characteristic parameters of the near-edge plasma are given. [ABSTRACT FROM AUTHOR]

In his account of scientific revolutions, Thomas Kuhn suggests that after a revolutionary change of theory, it is as if scientists are working in a different world. In this paper, we aim to show that the notion of world change is insightful. We contrast the reporting of the discovery of neon in 1898 with the discovery of hafnium in 1923. The one discovery was made when elements were identified by their atomic weight; the other discovery was made after scientists came to classify elements by their atomic number. By considering two instances of the reporting of the discovery of a new chemical element 25 years apart, we argue that it becomes clear how chemists can be said to have been responding to different worlds as a result of the change in the concept of a chemical element. They (1) saw, (2) did, and (3) reported different things as they conducted their research on the new chemical elements. [ABSTRACT FROM AUTHOR]

In this paper, the embedded-atom method was used to study the influence of different solute elements (Co, Cu, Yb) on the thermophysical properties of liquid Ni-based alloys. By exploring the relationship between surface tension, viscosity, diffusion coefficient and temperature of liquid Ni-based alloys with three solutes in the range of 1500 ~ 1900 K, we found that under certain components the surface tension of liquid Ni-based alloys with three solutes decreased as temperature increased. Except the case that the atomic radius of the same period decreased with the increase of the atomic number and influence of lanthanide and actinide contraction, the surface tension of liquid Ni-based alloys decreased with the increase of atomic number. The viscosity of liquid alloy showed a downward trend with increasing temperature, and the viscosity decreased exponentially with the temperature increasing under certain components. The variation trend of diffusion coefficient of the three kinds of atoms was similar to that of the temperature, which increased with the increase of temperature under the same component. Especially, the diffusion coefficient increases exponentially with the increase of temperature under certain components. These simulated data provided necessary thermophysical parameters for non-equilibrium dynamics analysis of liquid-phase alloys and also supplied a sound theoretical basis for exploring the internal physical mechanism of "liquid microstructures–thermophysical properties–preferred phase of nucleation". [ABSTRACT FROM AUTHOR]

This paper examines radiation-shielding abilities of oxyfluoro-tellurite-zinc glasses in the chemical form of AlF3–TeO2–ZnO under the substitution of AlF3 by ZnO. Gamma-ray- and neutron-shielding properties were tested in terms of mass attenuation coefficient (μ/ρ), half value layer, mean free path, effective atomic numbers (Zeff), effective electron density (Neff) and removal cross-section (ΣR). The μ/ρ values of the glasses were generated by Geant4 simulations over an extended energy range and then the generated data were confirmed via XCOM software. The results showed that both gamma-ray- and neutron-shielding efficiencies of the selected glasses evolved by substituting of AlF3 by ZnO. Nuclear radiation-shielding abilities of the current glass systems were compared with that of some conventional shielding materials and newly developed HMO glasses. It can be concluded that oxyfluoro-tellurite-zinc glasses could be useful to design novel shields for radiation protection applications. [ABSTRACT FROM AUTHOR]

In this paper, new lead borate glass system in the chemical form of 40B2O3–40PbO–20Li2O3–xZrO2; where x = 0, 0.25, 0.50, 1, and 1.5 mol% has been synthesized. Gamma-ray shielding properties of these glasses have been tested in terms of mass attenuation coefficient (μ/ρ), half value layer (HVL), effective atomic number (Zeff), mean free path (MFP), and exposure build-up factor (EBF). The μ/ρ values of the prepared glasses were generated by FLUKA Monte Carlo simulations over an extended energy range of 0.015–15 MeV, and then, the generated data were verified using the calculated values of XCOM software. The results showed that gamma-ray shielding ability of BPLZ0.00 is superior among the other prepared glasses. Moreover, the gamma-ray shielding properties of the current glass system have been compared with that of some commercial glasses and newly developed HMO glasses. It can be concluded that the prepared glass system could be useful to design and/or develop novel shields for radiation protection applications. [ABSTRACT FROM AUTHOR]

This paper examines the utility of some newly developed tellurite-based glasses in the form of (100 - x - y) TeO 2 - x TiO 2 - y ZnO , where (x, y)=(5,10), (5,30), (10,10), (10,15), (15,5), and (15,10) mol % for potential use in radiation protection applications. Mass attenuation coefficient (μ / ρ) which is an essential parameter to study the radiation shielding properties was obtained for each proposed glass using GEANT4 toolkit for photon energies 1 keV–10 MeV. The simulation values were compared with the theoretical ones calculated by WinXCOM program. The obtained μ / ρ results were then utilized to calculate all the other important radiation shielding parameters such as mean free path, effective atomic number (Z eff) , and half-value layer for the glasses involved. Additionally, neutrons shielding properties in the terms of removal cross section were computed for each glass. The results reveal that the proposed glasses show the best shielding features against both gamma-ray and neutrons as compared with some commercial glasses, concretes, and HMO glasses. TeO 2 - TiO 2 - ZnO glasses would be useful for various radiation protection applications, especially those related to exposure control. [ABSTRACT FROM AUTHOR]

This paper focuses on examining the radiation shielding features of seven boro-tellurite glasses in the form of TeO2–B2O3–SrCl2–LiF–Bi2O3. Gamma rays and neutrons shielding features of these glasses have been tested in terms of mass attenuation coefficient (μ/ρ), half value layer (HVL), mean free path (MFP), effective atomic number (Zeff), and removal cross section (∑R). The μ/ρ values of the present glasses were simulated by Geant4 Monte Carlo simulations over an extended energy range of 0.015 − 20 MeV and then the generated data were verified using the calculated values of WinXCOM software. Additionally, geometric progression (G–P) method was used to estimate gamma ray exposure buildup factor (EBF) for the prepared glasses. It is noted that μ/ρ and Zeff values increase, while MFP and HVL values decrease as TeO2 content increases in the glass sample. The EBF values would be useful to design or develop the present glasses for gamma shielding applications. Results reveal that the present glasses have good capability for gamma rays shielding compared with some commercial radiation shielding materials. [ABSTRACT FROM AUTHOR]

In the current paper, glass samples were prepared from the composition xGd2O3–(30-x)Y2O3–70B2O3 (where x = 5, 10, 15, 20 and 25 mol%) via the technique of melt-quenching. Various optical parameters and inter-atomic separation were evaluated for the fabricated samples. The results showed that the inter-substitution of Y2O3 content in replacement with Gd2O3 content in the glass matrix shows structural variation in the glass. The density increases from 3.5521 to 4.1613 g/cm3 with increase in Gd2O3 content that signifies the role of Gd2O3 being a glass modifier. The transmission spectra of the glass sample show more than 85% transmittance suggesting their superior transparency in the visible region. Also, several important shielding parameters of the prepared glass system have been computationally determined via the Geant4 model and the results were compared with Phy-X/PDS database software. The results revealed that the mass attenuation factor (µ/ρ) obtained by utilizing the two different toolkits are in agreement. The transmission fraction and the half value layer parameters of the glass system indicate that the glass sample with higher Gd concentration provides a better gamma blocking ability thanks to the high atomic number of Gd. [ABSTRACT FROM AUTHOR]

This paper argues that the field of chemistry underwent a significant change of theory in the early twentieth century, when atomic number replaced atomic weight as the principle for ordering and identifying the chemical elements. It is a classic case of a Kuhnian revolution. In the process of addressing anomalies, chemists who were trained to see elements as defined by their atomic weight discovered that their theoretical assumptions were impediments to understanding the chemical world. The only way to normalize the anomalies was to introduce new concepts, and a new conceptual understanding of what it is to be an element. In the process of making these changes, a new scientific lexicon emerged, one that took atomic number to be the defining feature of a chemical element. [ABSTRACT FROM AUTHOR]

The most frequently used methods to reduce fusion and total reaction excitation functions were investigated in a very recent paper Canto et al. (Phys Rev C 92:014626, ). These methods are widely used to eliminate the influence of masses and charges in comparisons of cross sections for weakly bound and tightly bound systems. This study reached two main conclusions. The first is that the fusion function method is the most successful procedure to reduce fusion cross sections. Applying this method to theoretical cross sections of single channel calculations, one obtains a system independent curve (the fusion function), that can be used as a benchmark to fusion data. The second conclusion was that none of the reduction methods available in the literature is able to provide a universal curve for total reaction cross sections. The reduced single channel cross sections keep a strong dependence of the atomic and mass numbers of the collision partners, except for systems in the same mass range. In the present work we pursue this problem further, applying the reduction methods to systems within a limited mass range. We show that, under these circumstances, the reduction of reaction data may be very useful. [ABSTRACT FROM AUTHOR]

Sample composition is a very important but easily ignored factor affecting the measurement of radionuclides in biological samples. In this paper, we study the effect of the chemical composition of the standard calibration source on determining radionuclides using Laboratory Sourceless Object Calibration Software. Results show that the accuracy of determining radionuclides emitting low-energy photons (<100 keV) strongly depends on the differences between the average atomic numbers of the test samples and selected standard reference material (SRM). We also find that high moisture content reduces detection efficiency, especially for low-energy gamma rays. [ABSTRACT FROM AUTHOR]

The characterisation of the microstructure and micromechanical behaviour of paint is key to a range of problems related to the conservation or technical art history of paintings. Synchrotron-based X-ray laminography is demonstrated in this paper to image the local sub-surface microstructure in paintings in a non-invasive and non-destructive way. Based on absorption and phase contrast, the method can provide high-resolution 3D maps of the paint stratigraphy, including the substrate, and visualise small features, such as pigment particles, voids, cracks, wood cells, canvas fibres etc. Reconstructions may be indicative of local density or chemical composition due to increased attenuation of X-rays by elements of higher atomic number. The paint layers and their interfaces can be distinguished via variations in morphology or composition. Results of feasibility tests on a painting mockup (oak panel, chalk ground, vermilion and lead white paint) are shown, where lateral and depth resolution of up to a few micrometres is demonstrated. The method is well adapted to study the temporal evolution of the stratigraphy in test specimens and offers an alternative to destructive sampling of original works of art. [ABSTRACT FROM AUTHOR]

In this paper we study the problem of uniqueness of solutions to the Hartree and Hartree-Fock equations of atoms. We show, for example, that the Hartree-Fock ground state of a closed shell atom is unique provided the atomic number Z is sufficiently large compared to the number N of electrons. More specifically, a two-electron atom with atomic number $${Z\geqq 35}$$ has a unique Hartree-Fock ground state given by two orbitals with opposite spins and identical spatial wave functions. This statement is wrong for some Z > 1, which exhibits a phase segregation. [ABSTRACT FROM AUTHOR]