bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light-emitting diodes with Ge(Si) nanoislands embedded in photonic crystals
Authors: Shmagin V B , Yablonskiy A N , Stepikhova M V , Yurasov D V , Mikhaylov A N , Tetelbaum D I , Rodyakina E E , Morozova E E , Shengurov D V , Kraev S A , Yunin P A , Belov A I , Novikov A V 
Published: January 2024

Abstract
Room temperature lateral p+–i–n+ light-emitting diodes (LEDs) with photonic crystals embedded in the i-region were fabricated on structures with Ge(Si) self-assembled islands and their optical properties were investigated. The use of preliminary amorphization and solid phase epitaxy of the implanted p+ and n+ contact regions made it possible to reduce the impurity activation temperature from 800 °С–1100 °С to 600 °С, which corresponds to the growth temperature of Ge(Si) islands. This resulted in a significant reduction of the detrimental effect of the high-temperature annealing used for diode formation on the intensity and spectral position of the luminescence signal from the islands. It was shown that significant enhancement (more than an order of magnitude) of room temperature electroluminescence of Ge(Si) islands in the spectral range of 1.3–1.55 μm can be achieved due to their interaction with different modes of the photonic crystals. The measured radiation power of the obtained diodes in the spectral range of 1.3–1.55 μm exceeds 50 pW at a pump current of 8 mA, which is an order of magnitude higher than the previously achieved values for micro-LEDs with Ge(Si) nanoislands. The obtained results open up new possibilities for the realization of silicon-based light emitting devices operating at telecommunication wavelengths.
Analyzer-free hard x-ray interferometry
Authors: Bertilson M , von Hofsten O , Maltz J S , Taphorn K , Herzen J , Danielsson M 
Published: January 2024

Abstract

Objective. To enable practical interferometry-based phase contrast CT using standard incoherent x-ray sources, we propose an imaging system where the analyzer grating is replaced by a high-resolution detector. Since there is no need to perform multiple exposures (with the analyzer grating at different positions) at each scan angle, this scheme is compatible with continuous-rotation CT apparatus, and has the potential to reduce patient radiation dose and patient motion artifacts. Approach. Grating-based x-ray interferometry is a well-studied technique for imaging soft tissues and highly scattering objects embedded in such tissues. In addition to the traditional x-ray absorption-based image, this technique allows reconstruction of the object phase and small-angle scattering information. When using conventional incoherent, polychromatic, hard x-ray tubes as sources, three gratings are usually employed. To sufficiently resolve the pattern generated in these interferometers with contemporary x-ray detectors, an analyzer grating is used, and consequently multiple images need to be acquired for each view angle. This adds complexity to the imaging system, slows image acquisition and thus increases sensitivity to patient motion, and is not dose efficient. By simulating image formation based on wave propagation, and proposing a novel phase retrieval algorithm based on a virtual grating, we assess the potential of a analyzer-grating-free system to overcome these limitations. Main results. We demonstrate that the removal of the analyzer-grating can produce equal image contrast-to-noise ratio at reduced dose (by a factor of 5), without prolonging scan duration. Significance. By demonstrating that an analyzer-free CT system, in conjuction with an efficient phase retrieval algorithm, can overcome the prohibitive dose and workflow penalties associated grating-stepping, an alternative path towards realizing clinical inteferometric CT appears possible.
Interactive content-based image retrieval with deep learning for CT abdominal organ recognition
Authors: Lo Chung-Ming , Wang Chi-Cheng , Hung Peng-Hsiang 
Published: January 2024

Abstract

Objective. Recognizing the most relevant seven organs in an abdominal computed tomography (CT) slice requires sophisticated knowledge. This study proposed automatically extracting relevant features and applying them in a content-based image retrieval (CBIR) system to provide similar evidence for clinical use. Approach. A total of 2827 abdominal CT slices, including 638 liver, 450 stomach, 229 pancreas, 442 spleen, 362 right kidney, 424 left kidney and 282 gallbladder tissues, were collected to evaluate the proposed CBIR in the present study. Upon fine-tuning, high-level features used to automatically interpret the differences among the seven organs were extracted via deep learning architectures, including DenseNet, Vision Transformer (ViT), and Swin Transformer v2 (SwinViT). Three images with different annotations were employed in the classification and query. Main results. The resulting performances included the classification accuracy (94%–99%) and retrieval result (0.98–0.99). Considering global features and multiple resolutions, SwinViT performed better than ViT. ViT also benefited from a better receptive field to outperform DenseNet. Additionally, the use of hole images can obtain almost perfect results regardless of which deep learning architectures are used. Significance. The experiment showed that using pretrained deep learning architectures and fine-tuning with enough data can achieve successful recognition of seven abdominal organs. The CBIR system can provide more convincing evidence for recognizing abdominal organs via similarity measurements, which could lead to additional possibilities in clinical practice.
Alternative analytical models for HTS tapes considering their AC hysteretic and resistive losses
Authors: Fernandes João F P , Bucho Luís F D , Ferreira da Silva F , Peixoto Inês S P , Vaschetto Silvio , Costa Branco P J 
Published: January 2024

Abstract
This work proposes two alternative analytical models to evaluate the ac losses of high-temperature superconducting (HTS) tapes during their hysteretic and resistive modes. These models intend to extend the application range of state-of-the-art analytical models for current values higher than the critical one, i.e. for the resistive state, and to correctly predict the ac losses during the transition between the hysteretic and resistive modes. Two analytical models are proposed, one considering an extension of the Norris model for the HTS tape’s resistive mode and the other based on a sigmoid function to characterize the hysteretic losses and their smooth transition to the resistive mode. Analytical models capable of estimating ac losses of superconducting (SC) tapes are an important tool for the design of complex SC systems, such as SC fault current limiters, SC electrical machines and SC cables. The proposed models are validated experimentally, for a 1st generation BSCCO tape and a 2nd generation REBCO tape. Finite element simulation is also carried out to verify the accuracy of the proposed models. Results show that the proposed extended-Norris model presents some deviation at the transition between the hysteretic and resistive modes, while the sigmoid model presents very accurate results for the whole spectrum of applied current. Also, the parameters of the sigmoid models are independent of the tape geometry.
Resistance at 77 K of two Bi-2223 coils with superconducting joints prepared by incongruent melting
Authors: Kanazawa Shintetsu , Sekine Chihiro 
Published: January 2024

Abstract
A superconducting joint for multi-filamentary Bi2Sr2Ca2Cu3O10+δ
(Bi2223) tape, which has applications in nuclear magnetic resonance and magnetic resonance imaging, has been developed based on incongruent melting and multi-junction methods. In this study, the critical current limit, optimal oxygen annealing conditions, and reproducibility of this joint are experimentally evaluated. The results indicate that the critical current limit of the joint at 77 K is determined by that of the tape. The critical current limit was estimated to be about 40 A. Additional oxygen annealing after heat treatment below 1143 K. appears to have no effect on the critical current, and that above 1153 K slightly increases the critical current. It is found that the multi-junction method effectively increases the reproducibility of obtaining a high critical current. To obtain a high critical current at 77 K, the highest temperature in the joint creation process should be lowered to near the incongruent melting temperature of Bi2223 (about 1133 K in air). Two Bi2223 coils, each with one joint (four junctions), were prepared and their persistent current at 77 K was tested. A persistent current of above 20 A was measured with a resistance of about 10 pΩ.
Superconductivity of amorphous and crystalline Re–Lu films
Authors: Teknowijoyo Serafim , Gulian Armen 
Published: January 2024

AbstractWe report on superconducting properties of a novel material: rhenium-lutetium films. Different compositions of RexLu binary are explored fromx ≈ 3.8 to close to pure Re stoichiometry. The highest critical temperature, up toTc≈7 K, is obtained forx ≈ 10.5 in accordance with electron dispersive spectroscopy results. Depending on the deposition conditions, polycrystalline or amorphous films are obtainable, both of which are interesting for practical use. Crystalline structure of polycrystalline phase is identified as a non-centrosymmetric superconductor using grazing incidence x-ray diffractometry. Superconducting properties were characterized both resistively and magnetically. Magnetoresistivity and AC/DC susceptibility measurements allowed us to determineHc1andHc2of these films, as well as estimate coherence lengthξ(0)and magnetic penetration depthλL(0). We also provide information on surface morphology of these films. Demonstration of superconductivity in this material justifies the point of view that Lu plays a role of group 3 transition metal in period 6 of the Periodic table of elements. Then, in analogy with Re–Nb, Re–Ti, Re–Hf and Re–Zr, one can expect that crystalline Re–Lu also breaks time-reversal symmetry. If that is proven by future experiments, in combination with noncentrosymmetric feature, these films could be used for forming nonreciprocal current devices, such as superconducting diodes, without involvement of external magnetic fields.
Plasma elongation effects on energetic particle-induced geodesic acoustic modes in tokamaks
Authors: Chen Zhe , Ren Haijun , M Roach Colin 
Published: January 2024

Abstract
Plasma elongation effects on energetic particle-induced geodesic acoustic modes (EGAMs) are theoretically investigated by using gyro-kinetic equations and the Miller local equilibrium model. Including an arbitrary elongation κ and a finite radial derivative

s
κ

=
r

∂
r

κ

/

κ

, a general EGAM dispersion relation is obtained for an arbitrary energetic particle (EP) distribution. In particular, we obtain analytical EGAM dispersion relations for both the double-shifted Maxwellian distribution and the standard slowing-down distribution of EPs. In both cases, the frequency of the unstable EGAM branch decreases slowly with increasing elongation, while its growth rate decreases rapidly with κ when the ratio of the EP to the bulk ion density,

n

h

/

n

i

⩾
0.1

. These trends agree well with previous GENE and ORB5 simulations (Di Siena et al 2018 Nucl. Fusion
58 106014), but differ significantly from the elongation effects on geodesic acoustic modes (GAMs) (Gao et al 2009 Nucl. Fusion
49 045014). The portion of the EGAM dispersion relation accounting for the first-order finite-orbit-width shows greater sensitivity to frequency compared to that of GAM, which explains the smaller variations in the frequency of EGAM as κ changes. When the EP number is small (typically,

n

h

/

n

i

≈
5
%

) in the double-shifted Maxwellian case, the growth rate of EGAMs first increases with the increasing elongation and then decreases, while it monotonically increases with κ in the slowing-down case. Furthermore, the effects of s

κ
on EGAMs are similar to the elongation κ effects but weaker.
Diagnostic weight functions in constants-of-motion phase-space
Authors: Rud M. , Moseev D. , Jaulmes F. , Bogar K. , Eriksson J. , Järleblad H. , Nocente M. , Prechel G. , Reman B.C.G. , Schmidt B.S. , Snicker A. , Stagner L. , Valentini A. , Salewski M. 
Published: January 2024

Abstract
The fast-ion phase-space distribution function in axisymmetric tokamak plasmas is completely described by the three constants of motion: energy, magnetic moment and toroidal canonical angular momentum. In this work, the observable regions of constants-of-motion phase-space, given a diagnostic setup, are identified and explained using projected velocities of the fast ions along the diagnostic lines-of-sight as a proxy for several fast-ion diagnostics, such as fast-ion

D

α

spectroscopy, collective Thomson scattering, neutron emission spectroscopy and gamma-ray spectroscopy. The observable region in constants-of-motion space is given by a position condition and a velocity condition, and the diagnostic sensitivity is given by a gyro-orbit and a drift-orbit weighting. As a practical example, 3D orbit weight functions quantifying the diagnostic sensitivity to each point in phase-space are computed and investigated for the future COMPASS-Upgrade and MAST-Upgrade tokamaks.
Plasma-based particle sources
Authors: Fuchs M. , Andonian G. , Apsimon O. , Büscher M. , Downer M.C. , Filippetto D. , Lehrach A. , Schroeder C.B. , Shadwick B.A. , Thomas A.G.R. , Vafaei-Najafabadi N. , Xia G. 
Published: January 2024

Abstract
High-brightness particle beams generated by advanced
accelerator concepts have the potential to become an essential part
of future accelerator technology. In particular, high-gradient
accelerators can generate and rapidly accelerate particle beams to
relativistic energies. The rapid acceleration and strong confining
fields can minimize irreversible detrimental effects to the beam
brightness that occur at low beam energies, such as emittance growth
or pulse elongation caused by space charge forces. Due to the high
accelerating gradients, these novel accelerators are also
significantly more compact than conventional technology. Advanced
accelerators can be extremely variable and are capable of generating
particle beams with vastly different properties using the same
driver and setup with only modest changes to the interaction
parameters. So far, efforts have mainly been focused on the
generation of electron beams, but there are concepts to extend the
sources to generate spin-polarized electron beams or positron beams.
The beam parameters of these particle sources are largely determined
by the injection and subsequent acceleration processes. Although,
over the last decade there has been significant progress, the
sources are still lacking a sufficiently high 6-dimensional (D)
phase-space density that includes small transverse emittance, small
energy spread and high charge, and operation at high repetition
rate. This is required for future particle colliders with a
sufficiently high luminosity or for more near-term applications,
such as enabling the operation of free-electron lasers (FELs) in the
X-ray regime. Major research and development efforts are required
to address these limitations in order to realize these approaches
for a front-end injector for a future collider or next-generation
light sources. In particular, this includes methods to control and
manipulate the phase-space and spin degrees-of-freedom of ultrashort
plasma-based electron bunches with high accuracy, and methods that
increase efficiency and repetition rate. These efforts also include
the development of high-resolution diagnostics, such as full 6D
phase-space measurements, beam polarimetry and high-fidelity
simulation tools.
A further increase in beam luminosity can be achieve through
emittance damping. Emittance cooling via the emission of synchrotron
radiation using current technology requires kilometer-scale damping
rings. For future colliders, the damping rings might be replaced by
a substantially more compact plasma-based approach. Here, plasma
wigglers with significantly stronger magnetic fields are used
instead of permanent-magnet based wigglers to achieve similar
damping performance but over a two orders of magnitude reduced
length.
In vivo soft tissue regenerative potential of flax seed mucilage self-assembled collagen aerogels
Authors: Kumari Punam , Ahina Kannoth Madappurakkal , Kannan Kiruba , Sreekumar Sreelekshmi , Lakra Rachita , Sivagnanam Uma Tiruchirapalli , Kiran Manikantan Syamala 
Published: January 2024

Abstract
The present study demonstrates the in vivo soft tissue regenerative potential of flax seed mucilage (FSM) reinforced collagen aerogels in Wistar rats. The physiochemical, mechanical, and thermal properties were significantly improved upon the incorporation of flax mucilage into collagen when compared to the native collagen scaffold. In addition, the functional group of flax mucilage notably contributed to a better anti-oxidative potential than the control collagen. The flax mucilage-reinforced collagen at 4 mg ml−1 concentration showed a 2-fold increase in porosity compared to native collagen. The tensile strength of native collagen, 2 mg ml−1, and 4 mg ml−1 FSM reinforced collagen was 5.22 MPa, 9.76 MPa, and 11.16 MPa, respectively, which indicated that 2 mg ml−1 and 4 mg ml−1 FSM showed an 87% and 113% percentage increase respectively in tensile strength compared to the native collagen control. FSM-reinforced biomatrix showed 97% wound closure on day 15 post-wounding, indicating faster healing than controls, where complete healing occurred only on day 21. The mechanical properties of skin treated with FSM-reinforced collagen scaffold post-healing were considerably better than native collagen. The histological and immunohistochemistry analysis also showed complete restoration of wounded tissue like intact normal skin. The findings paved the way for the development of collagen-polysaccharide mucilage wound dressing materials and their further application in skin tissue engineering.
Environmental Performance Indicators as a Tool to Evaluate Urban Development Priorities in Fayoum Governorate.
Authors: Hesham Yomna , Yousry Ahmed , Qutb Seham Mostafa , Saleh Nada 
Published: January 2024

Abstract
Environmental performance assessment, especially EPI (Environmental Performance Indicators), is a quantifiable environmental management tool that provides guidance to improve the efficiency of development processes from an environmental perspective. It relies on two main policies: environmental health and ecosystem vitality. The study aims to evaluate the environmental performance indicators of the Fayoum governorate according to the specificity of its condition. The goal is to achieve a balance between urban development processes and the vitality of its ecosystem. The problem of research is the absence of tools and indicators of environmental performance suitable for the specificity of each region and system separately. This can be addressed by selecting environmental performance indicators appropriate for the study area based on the methodology of internationally recognized Environmental Performance Indicators (EPI). These selected indicators are then applied in the governorate to develop a set of policies and strategies that are appropriate to the issues they face from an environmental performance perspective.
Degradation mechanisms and modification strategies of nickel-rich NCM cathode in lithium-ion batteries
Authors: Li Dongyang , Liu Wenbo , Liang Wenyu , Xu Rui 
Published: January 2024

Abstract
Ni-rich Lithium Nickel Cobalt Manganese Oxide (NCM) cathode materials have garnered attention for their high specific capacity, but they grapple with issues of cycling stability, thermal performance, and safety. This concise yet comprehensive review embarks on an exploration, commencing with an examination of fundamental characteristics, including crystallographic structures and electrochemical properties. It delves into the intricate failure mechanisms contributing to capacity degradation and thermal instability. The review places emphasis on major material-focused modification techniques, encompassing surface coatings and multifunctional additives, all scrutinized for their potential to enhance both performance and safety. Furthermore, it spotlights pivotal research domains, notably novel synthesis methods, positioned to reshape the landscape of Ni-rich NCM technology. The review also emphasizes future development directions, aiming for simplified and cost-effective methodologies to tackle the complexities of nickel-rich cathodes. Ultimately, this review offers a forward-looking analysis, envisioning a future marked by safer, higher-capacity lithium-ion batteries, underscoring an enduring commitment to scientific and technological progress.
Sputter-deposition of ultra-thin film stacks from EUROFER97 and tungsten: characterisation and interaction with low-energy D and He ions
Authors: Shams-Latifi Jila , Pitthan Eduardo , Tran Tuan Thien , Kaur Rajdeep , Primetzhofer Daniel 
Published: January 2024

Abstract
We have sputter-deposited stacks of ultrathin layers from EUROFER97 and tungsten on silicon substrates. Ion beam analysis techniques are used for composition characterisation and microscopy methods are employed for structural examination. The films are subsequently studied by time-of-flight low-energy ion scattering (ToF-LEIS) for primary 10 keV He+ and 8 keV D+ ions to demonstrate an approach of providing accurate and precise experimental reference electronic stopping cross-sections for fusion-relevant steels. The energy-converted ToF-LEIS spectra are compared to Monte-Carlo simulations for quantitative analysis explicitly considering the influence of plural and multiple scattering. We discuss the deduced stopping cross-sections of EUROFER97 in comparison to predictions by SRIM using Bragg’s rule of stopping power additivity.
Deep insight into structural and optoelectronic properties of mixed anion perovskites
Authors: Wanniarachchi W A Chapa Pamodani , Eidsvåg Håkon , Arunasalam Thevakaran , Ravirajan Punniamoorthy , Velauthapillai Dhayalan , Vajeeston Ponniah 
Published: January 2024

Abstract
Here we present the optoelectronic properties of pure inorganic lead-free halide perovskites in the form of Cs2AgBiX
6 (X = Br, Cl, F, I) using the density functional theory calculations on cubic phase (Fm

3

̅

m) and tetragonal phase (I4/m). First, all the structures of the two phases were optimized at the PBE level. Structural, electronic, optical properties, phonon, and thermal properties of Cs2AgBiX
6 in cubic (Fm

3

̅

m) and tetragonal phases (I4/m) were obtained using the VASP code. Tetragonal phases of all compounds of the form Cs2AgBiX
6, except Cs2AgBiBr6, are reported here for the very first time. Among all the Cs2AgBiX
6 (X = F, Cl, Br, I) structures, the cubic phase of Cs2AgBiBr6 was seen to have the highest absorption coefficient along with prominent electronic features that are favorable for optoelectronic applications. Thus, the cubic phase of Cs2AgBiBr6 was selected as the host lattice and bromine atoms were partly replaced with chlorine and iodine atoms. Electronic and optical properties of these mixed halide compounds of Cs2AgBiBr6−xFx, Cs2AgBiBr6−xClx, and Cs2AgBiBr6−xIx where x = 1, 2, 3, 4, 5 are investigated with hybrid functional HSE06 level. The electronic structure revealed that these mixed compounds exhibited indirect band gap nature regardless of the halide substitution (different x concentration) and the band gap of Cs2AgBiBr6 could be varied with the substitutions of fluorine, chlorine, and iodine atoms. Our in-depth analysis shows that Cs2AgBiBr6 and their mixed halides have the potential to become active double perovskite materials for photovoltaic applications and as photocatalysts for water splitting.