bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational analysis of the optical response of ZnSe with d-orbital defects
Authors: Pike Nicholas A , Pachter Ruth , Martinez Alan D , Cook Gary 
Published: February 2022

Abstract
The doping of wide band-gap semiconducting ZnSe by transition metal (TM) atoms finds applications from mid-infrared lasing, sensing, photoelectrochemical cells, to nonlinear optics. Yet understanding the response of these materials at the atomic and electronic level is lacking, particularly in comparing a range of TM dopants, which were studied primarily by phenomenological crystal-field theory. In this work, to investigate bulk ZnSe singly doped with first-row TM atoms, specifically Ti through Cu, we applied a first-principles approach and crystal-field theory to explain the origin of the infrared absorption. We show that the use of an appropriate exchange–correlation functional and a Hubbard U correction to account for electron correlation improved the determination of the electronic transitions in these systems. We outline an approach for the calculation of the crystal-field splitting from first-principles and find it useful in providing a measure of dopant effects, also in qualitative comparison to our experimental characterization for ZnSe doped with Fe, Cr, and Ni. Our calculated absorption spectra indicate absorption signatures in the mid-infrared range, while the absorption in the visible portion of the spectrum is attributed to the ZnSe host. Our calculations will potentially motivate further experimental exploration of TM-doped ZnSe. Finally, the methods used here provide a route towards computational high-throughput screening of TM dopants in III–V materials through a combination of the electronic band structure and crystal-field theory.
Surface degradation of laminated metal 226Ra foils used in school sealed sources in the UK
Authors: Whitcher R , Page R D , Cole P R , Chappell S , Hicks J 
Published: February 2022

Abstract
In the few years leading up to this research, CLEAPSS noticed a small but steadily increasing number of calls from UK schools regarding a red-brown discolouration on the surface of the foil of their radium source. There were no reports of this type of discolouration on foils of other radionuclides. CLEAPSS and the University of Liverpool collaborated to investigate the nature and cause of this discolouration and the likelihood that the foils were becoming unsafe. The evidence indicates that the discolouration is principally caused by some combination of silicon, sulfur and possibly lead from within the foil diffusing into the face layer. There is no indication currently that the face layers are fragmenting on these foils, but the longer-term integrity of the discoloured foils now becomes questionable. Given the age of the foils and the radiotoxicity of radium, the recommendation from this research is that discoloured foils should be taken out of service and disposed.
Artificial intelligence based deconvolving on megavoltage photon beam profiles for radiotherapy applications
Authors: Weidner Jan , Horn Julian , Kabat Christopher Nickolas , Stathakis Sotirios , Geissler Philipp , Wolf Ulrich , Poppinga Daniela 
Published: February 2022

Abstract

Objective. The aim of this work is an AI based approach to reduce the volume effect of ionization chambers used to measure high energy photon beams in radiotherapy. In particular for profile measurements, the air-filled volume leads to an inaccurate measurement of the penumbra. Approach. The AI-based approach presented in this study was trained with synthetic data intended to cover a wide range of realistic linear accelerator data. The synthetic data was created by randomly generating profiles and convolving them with the lateral response function of a Semiflex 3D ionization chamber. The neuronal network was implemented using the open source tensorflow.keras machine learning framework and a U-Net architecture. The approach was validated on three accelerator types (Varian TrueBeam, Elekta VersaHD, Siemens Artiste) at FF and FFF energies between 6 MV and 18 MV at three measurement depths. For each validation, a Semiflex 3D measurement was compared against a microDiamond measurement, and the AI processed Semiflex 3D measurement was compared against the microDiamond measurement. Main results. The AI approach was validated with dataset containing 306 profiles measured with Semiflex 3D ionization chamber and microDiamond. In 90% of the cases, the AI processed Semiflex 3D dataset agrees with the microDiamond dataset within 0.5 mm/2% gamma criterion. 77% of the AI processed Semiflex 3D measurements show a penumbra difference to the microDiamond of less than 0.5 mm, 99% of less than 1 mm. Significance. This AI approach is the first in the field of dosimetry which uses synthetic training data. Thus, the approach is able to cover a wide range of accelerators and the whole specified field size range of the ionization chamber. The application of the AI approach offers an quality improvement and time saving for measurements in the water phantom, in particular for large field sizes.
Confinement properties of L-mode plasmas in ASDEX Upgrade and full-radius predictions of the TGLF transport model
Authors: Angioni C. , Gamot T. , Tardini G. , Fable E. , Luda T. , Bonanomi N. , Kiefer C.K. , Staebler G.M. , the ASDEX Upgrade Team  , the EUROfusion MST1 Team  
Published: February 2022

Abstract
The properties of L-mode confinement have been investigated with a set of dedicated experiments in ASDEX Upgrade and with a related modelling activity with the transport code ASTRA and the quasi-linear turbulent transport model TGLF–SAT2, with boundary conditions at the separatrix. The values at the boundary have been set by the two-point model for the electron temperature, with the ion temperature proportional to the electron temperature by a constant factor, and the electron density set by a constant fraction of the volume averaged density. The influx of neutrals has been set through a feedback procedure which ensures that in the simulation the same particle content as in the experiment is obtained. The sensitivity of the results under considerable variations in the choice of the boundary conditions has been investigated and found to be limited. The predictions of this full-radius modelling set-up have been compared to experimental results covering a scan in electron cyclotron resonance heating (ECRH) power in both hydrogen and deuterium plasmas, a plasma current scan with fixed magnetic field, under both ECRH and neutral beam injection heating, an increase in plasma density with constant ECRH power in hydrogen plasmas, as well as variations of the fraction of electron and ion heating at approximately constant total heating power, as well as a change of main ion from deuterium to hydrogen. The ASTRA-TGLF predictions have been found to reproduce all of the experimentally explored dependences with relatively good accuracy, providing evidence, for the first time to our knowledge, that the main properties of L-mode confinement can be reproduced by conventional full-radius transport modelling with a quasi-linear turbulent transport model. Evidences of largest disagreement, although usually not exceeding the 20%, have been found at high electron heating power, where TGLF underpredicts the electron and particularly the ion thermal stored energies, and in the current dependence of confinement, which, in electron heated conditions, is predicted to be weaker than in the experiment.
Design and performance of the GERDA low-background cryostat for operation in water
Authors: Knöpfle K.T. , Schwingenheuer B. 
Published: February 2022

Abstract
In searching for the neutrinoless double-beta decay of
76Ge the GERmanium Detector Array (Gerda) experiment
at the Infn Laboratori Nazionali del Gran Sasso has
achieved an unprecedented low background of well below
10-3 cts/(keV·kg·yr) in the region of interest. It
has taken advantage of the first realization of a novel shielding
concept based on a large cryostat filled with a liquid noble gas
that is immersed in a water tank. The germanium detectors are
operated without encapsulation in liquid argon. Argon and water
shield the environmental background from the laboratory and the
cryostat construction materials to a negligible level. The same
approach has been adopted in the meantime by various experiments.
This paper provides an overview of the design and the operation
experience of the 64 m3 liquid argon cryostat and its associated
infrastructure. The discussion inludes the challenging safety issues
associated with the operation of a large cryostat in a water
tank.
Characterization and comparison of glass electrodes
Authors: Kanishka R. , Bhatnagar V. 
Published: February 2022

Abstract
This paper presents the study on the characterization of
glass electrodes, which are one of the main components of detectors
like Resistive Plate Chambers (RPCs). The RPCs are being used in
various ongoing High Energy Physics experiments, e.g., BELLE at KEK,
CMS at LHC, and would be used in the near future experiments e.g.,
INO-ICAL in India. The characterization of glass electrodes has been
done to understand the factors like quality of glass that can help
in improving the detector's performance. The glass samples chosen
were procured locally Asahi (A), Saint Gobain (S), Modi (M) that are
easily available in Indian industry. The characterization includes
the tests to study the optical, surface, physical, electrical
properties, the composition of glass samples, and leakage
currents. This paper adds new information to the existing body of
research on the subject. Based on the techniques discussed in the
paper a comparison of the measurements among the three different
types of glass electrodes has been done. This study helps us to
determine the best quality of glass that can be chosen for better
operation of the detectors.
Results of the first implementation of RF phase signature matching at LANSCE
Authors: Huang E.-C. , Taylor C.E. , Roy P.K. , Upadhyay J. 
Published: February 2022

Abstract
The LINAC at the Los Alamos Neutron Science Center (LANSCE)
has been utilizing the Delta-t method to match the RF cavities to
the design acceleration parameters since its commissioning in 1972.
The differences in time-of-flight between two subsequent Beam
Position and Phase Monitors (BPPMs) are measured with both
accelerated and drifting beams, depending on the whether the module
is set to on or off. The algorithm optimizes the module amplitude
and phase via iterative measurements if the initial phase is in the
vicinity of the design value. With an upgrade to a faster readout
system, a scan over the whole RF cavity phase range requires
relatively less time than the classical optimization procedure. The
Phase Scan Signature Matching (PSSM) method provides a
time-efficient method that ensures the phase selection lands on the
bunching side and empowers future analyses to build module-specific
models. The PSSM also utilizes a direct model to determine the
correct amplitude to sub-percent level instead of using linearized
matrices. Furthermore, lacking a reliable energy measurement method
in the LINAC, we measure the beam phases at two downstream locations
to increase the precision of energy measurements. In this letter,
we also discuss the sensitivities of PSSM, error propagation, and
the implementation results for the 2019 and 2020 beam cycles.
In vitro and in vivo study of magnesium containing bioactive glass nanoparticles modified gelatin scaffolds for bone repair
Authors: Sun Yi , Lin Jie , Li LeiLei , Jia Kai , Xia Wen , Deng Chao 
Published: February 2022

Abstract
Magnesium containing bioactive glass nanoparticles modified gelatin scaffolds (MBGNs/Gel scaffolds) have shown recently the potential for bone regeneration due to its good biocompatibility, bioresorbability and bioactivity. Nevertheless, its use is limited by its complicated manufacturing process and a relatively expensive price. In this study, MBGNs were prepared by sol–gel process. The MBGNs/Gel was synthesized by a simple immersion method. SEM, transmission electron microscopy and dynamic light scattering analysis showed that the particles had spherical morphology with mean particle size of 100 nm. The MBGNs/Gel scaffolds were observed by SEM. The scaffolds showed connected pore structure with pore size ranging from 100 to 300 μm. SEM images with high magnification showed the existence of MBGNs on the surface of micro-pores. The ion release results revealed the release of Mg, Ca and Si elements from the MBGNs. MTT assay and cytotoxicity studies indicated that, the scaffolds provide a suitable ion related micro-environment for cell attachment and spreading. The Reverse Transcription-Polymerase Chain Reaction (RT-PCR) results showed the scaffolds could promote the osteogenesis of MC3T3-E1. The in vivo study also showed higher amount of new bone and trabecular bone which indicated excellent bone induction and conduction property of modified scaffolds. So, the developed MBGNs/Gel scaffolds are a potential candidate for bone regeneration applications.
Global gridded crop models underestimate yield responses to droughts and heatwaves
Authors: Heinicke Stefanie , Frieler Katja , Jägermeyr Jonas , Mengel Matthias 
Published: February 2022

Abstract
Extreme events can lead to crop yield declines, resulting in financial losses and threats to food security, and the frequency and intensity of such events is projected to increase. As global gridded crop models (GGCMs) are commonly used to assess climate change impacts on agricultural yields, there is a need to understand whether these models are able to reproduce the observed yield declines. We evaluated 13 GGCMs from the Inter-Sectoral Impact Model Intercomparison Project and compared observed and simulated impact of past droughts and heatwaves on yields for four crops (maize, rice, soy, wheat). We found that most models detect but underestimate the impact of droughts and heatwaves on yield. Specifically, the drought signal was detected by 12 of 13 models for maize and all models for wheat, while the heat signal was detected by eleven models for maize and six models for wheat. To investigate whether the difference between simulated and observed yield declines is due to a misrepresentation of simulated exposure to heat or water scarcity (i.e. misrepresentation of growing season), we analysed the relationship between average discrepancies between observed and simulated yield losses, and average simulated exposure to extreme weather conditions across all crop models. We found a positive correlation between simulated exposure to heat and model performance for heatwaves, but found no correlation for droughts. This suggests that there is a systematic underestimation of yield responses to heat and drought and not only a misrepresentation of exposure. Assuming that performance for the past indicates models’ capacity to project future yield impacts, models likely underestimate future yield decline from climate change. High-quality temporally and spatially resolved observational data on growing seasons will be highly valuable to further improve crop models’ capacity to adequately respond to extreme weather events.
An NAO-dominated mode of atmospheric circulation drives large decadal changes in wintertime surface climate and snow mass over Eurasia
Authors: Ye Kunhui , Messori Gabriele , Chen Deliang , Woollings Tim 
Published: February 2022

Abstract
The leading mode of wintertime atmospheric variability over the North Atlantic-North Eurasia sector is dominated by the North Atlantic Oscillation (NAO) and accounts for more than one third of the total variability. This study explores the influences of the leading mode on decadal climate variability of Northern Eurasia. We focus on the little-explored decadal covariations of surface air temperature (SAT), snowfall, snow water equivalent (SWE) and snow cover over the region, using extensive model output from the Coupled Model Intercomparison Project sixth phase. Recent decadal trends (−0.92σ per decade) in the leading mode identified, are found to be largely a manifestation of internal climate variability (at least two thirds from the most conservative estimate). These internally-generated decadal trends strongly contributed to recent trends in SAT, snowfall, SWE and snow cover over Eurasia. External forcings should have played a minor role over Eurasia as they usually suggest opposite decadal trends to those observed. An exception is found for snowfall and SWE in east Eurasia, for which external forcings may have driven a large part of the recent upward trends, equally as important as the NAO-dominated mode. This points to a complex interplay between internally-generated and externally-forced climate variability over Northern Eurasia. Model discrepancies are identified in reproducing the linkages between the leading mode and the Eurasian surface climate variability. The internally-generated variability of this leading mode thus represents a large source of uncertainty in future decadal climate projections over Eurasia and, due to the memory effects of snow, also in modelling springtime climate variability.
A slow review of the AGT correspondence
Authors: Le Floch Bruno 
Published: February 2022

Abstract
Starting with a gentle approach to the Alday–Gaiotto–Tachikawa (AGT) correspondence from its 6d origin, these notes provide a wide (albeit shallow) survey of the literature on numerous extensions of the correspondence up to early 2020. This is an extended writeup of the lectures given at the Winter School ‘YRISW 2020’ to appear in a special issue of J. Phys. A. Class S is a wide class of 4d

N
=
2

supersymmetric gauge theories (ranging from super-QCD (quantum chromodynamics) to non-Lagrangian theories) obtained by twisted compactification of 6d

N
=

(

2
,
0

)

superconformal theories on a Riemann surface C. This 6d construction yields the Coulomb branch and Seiberg–Witten geometry of class S theories, geometrizes S-duality, and leads to the AGT correspondence, which states that many observables of class S theories are equal to 2d conformal field theory (CFT) correlators. For instance, the four-sphere partition function of a 4d

N
=
2

S
U

(

2

)

superconformal quiver theory is equal to a Liouville CFT correlator of primary operators. Extensions of the AGT correspondence abound: asymptotically-free gauge theories and Argyres–Douglas theories correspond to irregular CFT operators, quivers with higher-rank gauge groups and non-Lagrangian tinkertoys such as T

N
correspond to Toda CFT correlators, and nonlocal operators (Wilson–’t Hooft loops, surface operators, domain walls) correspond to Verlinde networks, degenerate primary operators, braiding and fusion kernels, and Riemann surfaces with boundaries.
A multifunctional micropore-forming bioink with enhanced anti-bacterial and anti-inflammatory properties
Authors: Wang Mian , Li Wanlu , Luo Zeyu , Tang Guosheng , Mu Xuan , Kuang Xiao , Guo Jie , Zhao Zhibo , Flores Regina Sanchez , Jiang Zewei , Lian Liming , Japo Julia Olga , Ghaemmaghami Amir M , Zhang Yu Shrike 
Published: February 2022

Abstract
Three-dimensional (3D) bioprinting has emerged as an enabling tool for various biomedical applications, such as tissue regeneration and tissue model engineering. To this end, the development of bioinks with multiple functions plays a crucial role in the applications of 3D bioprinting technologies. In this study, we propose a new bioink based on two immiscible aqueous phases of gelatin methacryloyl (GelMA) and dextran, further endowed with anti-bacterial and anti-inflammatory properties. This micropore-forming GelMA-dextran (PGelDex) bioink exhibited excellent printability with vat-polymerization, extrusion, and handheld bioprinting methods. The porous structure was confirmed after bioprinting, which promoted the spreading of the encapsulated cells, exhibiting the exceptional cytocompatibility of this bioink formulation. To extend the applications of such a micropore-forming bioink, interleukin-4 (IL-4)-loaded silver-coated gold nanorods (AgGNRs) and human mesenchymal stem cells (MSCs) were simultaneously incorporated, to display synergistic anti-infection behavior and immunomodulatory function. The results revealed the anti-bacterial properties of the AgGNR-loaded PGelDex bioink for both Gram-negative and Gram-positive bacteria. The data also indicated that the presence of IL-4 and MSCs facilitated macrophage M2-phenotype differentiation, suggesting the potential anti-inflammatory feature of the bioink. Overall, this unique anti-bacterial and immunomodulatory micropore-forming bioink offers an effective strategy for the inhibition of bacterial-induced infections as well as the ability of immune-regulation, which is a promising candidate for broadened tissue bioprinting applications.
Refractive-diffractive hybrid optics array: comparative analysis of simulation and experiments
Authors: Low Mun Ji , Rohith Thazhe Madam , Kim Byunggi , Kim Seung-Woo , Suchand Sandeep C S , Murukeshan Vadakke Matham , Kim Young-Jin 
Published: February 2022

Abstract
Hybrid optical elements, which combine refractive and diffractive optical components to enhance optical performance by taking advantage of the optical characteristics of the individual components, have enormous potential for next-generation optical devices. However, there have not been many reports on the simulation methodology to characterize such hybrid optical systems. Here, we present a method for simulating a hybrid optical element realized by attaching an ultra-thin, flexible diffractive optics array onto a refractive optical element. The ultra-thin diffractive optical element is fabricated by direct-laser-writing using a femtosecond pulsed laser as the light source. A systematic investigation of the proposed simulation method, which does not require extensive hardware resources or computational time, but retains resolution and accuracy, is presented. The proposed scheme is validated by comparing simulation and experimental results. The simulation and experimental results on the spot size and focal length for the diffractive Fresnel zone plate (FZP) match well, with typical errors of less than 6%. The aspect ratio of the focal spot sizes at the compound and FZP focal planes of the hybrid optical system from the simulation and experiment also match quite well, with typical errors below 7%. This simulation scheme will expedite the designs for novel hybrid optical systems with optimal optical performances for specific applications, such as microfluidics and aberration-controlled optics.
Phased array ultrasonic S-scan testing of near-detection-surface defects based on a background subtraction algorithm
Authors: Tian Yukuo , Xu Guocheng , Wei Lingbo , Zhou Guanghao , Lin Yuting , Fan Qiuyue , Gu Xiaopeng 
Published: February 2022

Abstract
In phased array ultrasonic sector scanning testing, echoes from defects near the detection surface are often overlapped with interface echoes and cannot be characterized. Based on linear acoustic theory, a mathematical model combining the background subtraction and the sum of squares differences algorithm is established to extract the characteristics of near-detection-surface defect echoes. The upper surface of the artificial notch defect is used as a near-detection-surface defect for detection. Specially, linear interpolation algorithm is used to suppress the effect of residual interface echo on the defect echo feature extraction and the effect of different interpolation factors is analyzed. The defect location and size were calculated based on the extracted defect characteristics. The simulation and experimental results indicate that the model can effectively extract the near-detection-surface defect echoes characteristics. Furthermore, when the interpolated signal reaches at least 500 MHz, residual interface echoes can be effectively suppressed. More importantly, according to the extracted defect echo characteristics, the localization and quantitative accuracies of near-surface defects can reach 0.2 mm and 0.3 mm, respectively. These findings provide an effective strategy for phased array ultrasonic sector scanning testing of near-detection-surface defects.