bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenomenological potentials for the refractory metals Cr, Mo and W
Authors: Baldinozzi Gianguido , Pontikis Vassilis 
Published: May 2022

Abstract
Cohesion in the refractory metals Cr, Mo, and W is phenomenologically described in this work via a n-body energy functional with a set of physically motivated parameters that were optimized to reproduce selected experimental properties characteristic of perfect and defective crystals. The functional contains four terms accounting for the hard-core repulsion, the Thomas–Fermi kinetic energy repulsion and for contributions to the binding energy of s and d valence electrons. Lattice dynamics, molecular statics, and molecular dynamics calculations show that this model describes satisfactorily thermodynamic properties of the studied metals whereas, unlike other empirical approaches from the literature, predictions of phonon dispersion relations and of surface and point defect energetics reveal in fair good agreement with experiments. These results suggest that the present model is well adapted to large-scale simulations and whenever total energy calculations of thermodynamic properties are unfeasible.
Energy density as a probe of band representations in photonic crystals
Authors: Blanco de Paz M , Herrera M A J , Arroyo Huidobro P , Alaeian H , Vergniory M G , Bradlyn B , Giedke G , García-Etxarri A , Bercioux D 
Published: May 2022

Abstract
Topological quantum chemistry (TQC) has recently emerged as an instrumental tool to characterize the topological nature of both fermionic and bosonic band structures. TQC is based on the study of band representations and the localization of maximally localized Wannier functions. In this article, we study various two-dimensional photonic crystal structures analyzing their topological character through a combined study of TQC, their Wilson-loop (WL) spectra and the electromagnetic energy density. Our study demonstrates that the analysis of the spatial localization of the energy density complements the study of the topological properties in terms of the spectrum of the WL operator and TQC.
Modelling the atmospheric dispersion of radiotracers in small-scale, controlled detonations: validation of dispersion models using field test data
Authors: Thiessen Kathleen M , Kuča Petr , Helebrant Jan , Hůlka Jiří , Charnock Thomas W , Chouhan Sohan L , Ďúran Juraj , Fuka Vladimir , de With Govert , Mancini Francesco , Periáñez Raúl , Tay Bee Kiat , Trifunović Dejan , Walter Hartmut 
Published: May 2022

Abstract
A series of modelling exercises, based on field tests conducted in the Czech Republic, were carried out by the ‘Urban’ Working Groups as part of the International Atomic Energy Agency’s Environmental Modelling for Radiation Safety II, Modelling and Data for Radiological Impact Assessment (MODARIA) I and MODARIA II international data compilation and model validation programmes. In the first two of these programmes, data from a series of field tests involving dispersion of a radiotracer, 99mTc, from small-scale, controlled detonations were used in a comparison of model predictions with field measurements of deposition. In the third programme, data from a similar field test, involving dispersion of 140La instead of 99mTc, were used. Use of longer-lived 140La as a radiotracer allowed a greater number of measurements to be made over a greater distance from the dispersion point and in more directions than was possible for the earlier tests involving shorter-lived 99mTc. The modelling exercises included both intercomparison of model predictions from several participants and comparison of model predictions with the measured data. Several models (HotSpot, LASAIR, ADDAM/CSA-ERM, plus some research models) were used in the comparisons, which demonstrated the challenges of modelling dispersion of radionuclides from detonations and the need for appropriate meteorological measurements.
Highly stable semitransparent multilayer graphene/LaVO3 vertical-heterostructure photodetectors
Authors: Lee Jae Jun , Jung Dae Ho , Shin Dong Hee , Lee Hosun 
Published: May 2022

Abstract
A heterostructure composed of a combination of semi-metallic graphene (Gr) and high-absorption LaVO3 is ideal for high-performance translucent photodetector (PD) applications. Here, we present multilayer Gr/LaVO3 vertical-heterostructure semitransparent PDs with various layer numbers (L

n
). At L

n
= 2, the PD shows the best performance with a responsivity (R) of 0.094 A W−1 and a specific detectivity (D*) of 7.385 × 107 cm Hz1/2 W−1 at 532 nm. Additionally, the average visible transmittance of the PD is 63%, i.e. it is semitransparent. We increased photocurrent (PC) by approximately 13%, from 0.564 to 0.635 μA cm−2 by using an Al reflector on the semitransparent PD. The PC of an unencapsulated PD maintains about 86% (from 0.571 to 0.493 μA cm−2) of its initial PC value after 2000 h at 25 °C temperature/30% relative humidity, showing good stability. This behavior is superior to that of previously reported graphene-based PDs. These results show that these PDs have great potential for semitransparent optoelectronic applications.
Carbon nanofiber frameworks for Li metal batteries: the synergistic effect of conductivity and lithiophilic-sites
Authors: Yang Zhen , Li Zheng , Liu Yanqi , Song Zhaohai , Gao Zhihao , Zhang Jianmin , Zheng Zongmin 
Published: May 2022

Abstract
The utilization of carbon framework to guide the growth of the Li dendrites is an important theme for Li metal batteries. The conductivity and electronegative sites of carbon materials will greatly affect the nucleation of Li metal. However, how much these two contributing factors affect the Li plating/stripping stability should be considered. This work presents N, O doped carbon nanofiber framework (CNF) membrane as the interlayer for protecting the Li anode. The amounts of N and O elements and their ratios, the conductivity, the thickness of CNF membrane and their effects on the Li plating/stripping process have been fully analyzed. The voltage profile and the stability of Li plating/stripping process are evaluated by symmetric and asymmetrical coin cells. The lithiophilic heteroatom doped surface mainly works as an excellent guide during the Li plating process, whereas the conductivity and mechanical stability of CNF equalize the current density and confine the volume change in during cycling. With the optimized CNF membrane as the interlayer, both Li metal and Li–S full cells exhibit good capacity properties and cyclic stability.
Surface-capping engineering for electrically neutral surface of perovskite films and stable solar cells
Authors: Li Dongni , Wang Qiuwen , Zhao Lu , Sun Xiangyu , Song Tinglu , Liu Fangze , Wei Jing , Li Hongbo 
Published: May 2022

Abstract
Metal halide perovskite solar cells (PSCs) have developed rapidly in recent years, due to their high performance and low-cost solution-based fabrication process. These excellent properties are mainly attributed to the high defect tolerance of polycrystalline perovskite films. Meanwhile, these defects can also facilitate ion migration and carrier recombination, which cause the device performance and the long-term stability of PSCs to deteriorate heavily. Therefore, it is critical to passivate the defects, especially at the surfaces of perovskite grains where the defects are most concentrated due to the dangling bonds. Here we propose a surface-capping engineering (SCE) method to construct ‘dangling-bond-free’ surfaces for perovskite grains. Diamine iodide (methylenediammonium diiodide, MDAI2) was used to construct an electroneutral PbX6-MDA-PbX6 (X = Cl, Br or I) layer at the perovskite surfaces. Compared to the monovalent FA+ which can only coordinate one [PbX6]4− slab, the bivalent MDA2+ can coordinate two [PbX6]4− slabs on both sides, thus realizing a dangling-bond-free surface. Solar cells based on SCE-perovskite films exhibited a higher power conversion efficiency (PCE) of 21.6%, compared with 19.9% of the control group; and maintained over 96% of its initial PCE after 13 h during the maximum power point tracking test under continuous AM1.5G illumination, whereas the control group only lasted 1.5 h. Constructing a dangling-bond-free capping layer on the grain boundary opens new avenues for the fabrication of ultralow-defect polycrystalline semiconductors, paving the way to further improve the PCE and lifetime of PSCs.
Efficient molecular ferroelectric photovoltaic device with high photocurrent via lewis acid–base adduct approach
Authors: Gu Jiahao , Wang Chen , Xu Xiaoli , Xiao Lingbo , Li Jun , Zhao Jie , Zou Guifu 
Published: May 2022

Abstract
Traditional inorganic oxide ferroelectric materials usually have band gaps above 3 eV, leading to more than 80% of the solar spectrum unavailable, greatly limiting the current density of their devices just at μA cm−2 level. Therefore, exploring ferroelectric materials with lower band gaps is considered as an effective method to improve the performance of ferroelectric photovoltaic devices. Inorganic ferroelectric materials are often doped with transition metal elements to reduce the band gap, which is a complex doping and high temperature fabrication process. Recently, molecular ferroelectric materials can change the symmetry and specific interactions of crystals at the molecular level by chemically modifying or tailoring cations with high symmetry, enabling rational design and banding of ferroelectricity in the framework of perovskite simultaneously. Therefore, the molecular ferroelectric materials have a great performance for both excellent ferroelectricity and narrow band gap without doping. Here, we report a ferroelectric photovoltaic device employing an organic-inorganic hybrid molecular ferroelectric material with a band gap of 2.3 eV to obtain high current density. While the poor film quality of molecular ferroelectrics still limits it. The Lewis acid–base adduct is found to greatly improve the film quality with lower defect density and higher carrier mobility. Under standard AM 1.5 G illumination, the photocurrents of ∼1.51 mA cm−2 is achieved along with a device efficiency of 0.45%. This work demonstrates new possibilities for the application of molecular ferroelectric films with narrow band gaps in photovoltaic devices, and lays a foundation for Lewis acid–base chemistry to improve the quality of molecular ferroelectric thin films to obtain high current densities and device performance.
An accurate probabilistic model with detector resolution and Doppler broadening correction in list-mode MLEM reconstruction for Compton camera
Authors: Wu Chuanpeng , Zhang Siyuan , Li Liang 
Published: May 2022

Abstract

Objective. The Compton cameras have been researched for medical applications and radioactive material detection. It is challenging for the Compton camera to realize high-resolution reconstruction when the incident photon energy is below 200 keV. However, multiple kinds of nuclear medical radionuclides are in this energy range, such as 201Tl, 67Ga, 99mTc, and 123I. In this work, we propose an improved probabilistic model with correction of detector energy resolution, detector spatial resolution, and Doppler broadening effect. The proposed model is used for numerical calculation of the system matrix in the list-mode maximum likelihood expectation maximization (LM-MLEM) algorithm. Approach. The model can improve the imaging resolution of LM-MLEM reconstruction by taking Doppler broadening effect into account. It performs well, especially in the following situations: low-energy photon incidence below 200 keV or (and) small distance between scattering and absorbing positions. Main results. Firstly, three main factors that affect the angular resolution of the Compton camera are theoretically analyzed and quantitatively calculated. The results of the analysis indicate the necessity of including the Doppler broadening effect in the model. Secondly, the details and derivation of the proposed probabilistic model are described. Thirdly, both Monte Carlo (MC) simulations and experiments are carried out to verify the performance of the proposed algorithm. The simulations focus on the low-energy reconstruction in which 201Tl (70 keV) and 99mTc (141 keV) are simulated. And the experiments are based on a single-layer Compton camera composed of a Timepix3 detector. Significance. The results of the simulations and the Timepix3-based experiments are presented to verify the effectiveness of the proposed algorithm. The model improves the Compton imaging resolution when the photon energy is below 200 keV.
Colposcopic multimodal fusion for the classification of cervical lesions
Authors: Fan Yinuo , Ma Huizhan , Fu Yuanbin , Liang Xiaoyun , Yu Hui , Liu Yuzhen 
Published: May 2022

Abstract

Objective: Cervical cancer is one of the two biggest killers of women and early detection of cervical precancerous lesions can effectively improve the survival rate of patients. Manual diagnosis by combining colposcopic images and clinical examination results is the main clinical diagnosis method at present. Developing an intelligent diagnosis algorithm based on artificial intelligence is an inevitable trend to solve the objectification of diagnosis and improve the quality and efficiency of diagnosis. Approach: A colposcopic multimodal fusion convolutional neural network (CMF-CNN) was proposed for the classification of cervical lesions. Mask region convolutional neural network was used to detect the cervical region while the encoding network EfficientNet-B3 was introduced to extract the multimodal image features from the acetic image and iodine image. Finally, Squeeze-and-Excitation, Atrous Spatial Pyramid Pooling, and convolution block were also adopted to encode and fuse the patient’s clinical text information. Main results: The experimental results showed that in 7106 cases of colposcopy, the accuracy, macro F1-score, macro-areas under the curve of the proposed model were 92.70%, 92.74%, 98.56%, respectively. They are superior to the mainstream unimodal image classification models. Significance: CMF-CNN proposed in this paper combines multimodal information, which has high performance in the classification of cervical lesions in colposcopy, so it can provide comprehensive diagnostic aid.
An image encryption scheme by applying memristive Hindmarsh-Rose neuron model
Authors: Wang Yanzhang 
Published: May 2022

Abstract
Neurophysiological studies indicate that there are rich and complex dynamical characteristics in electrical actives between neurons. When neurons are stimulated by appropriate electromagnetic, the dynamical behavior for the nervous system can be changed, and electromagnetic has an important effect for the effectiveness of neurological diseases. To explore the complex dynamic effect of magnetic field in neuron activities, a new memristive HindMarsh-Rose neuron model can be developed by connecting a memristor into a simple 2 dimentional HindMarsh-Rose neuron model. It fond that the new neuron model has rich nonlinear dynamics and generate hidden attractors when changing electromagnetic induction. Neuron model as a nonlinear system, it has properties similar to a chaotic system system. So the memristive HindMarsh-Rose neuron model can be considered as a chaotic system to apply in image encryption algorithm. And an image encryption algorithm based on the memristive HindMarsh-Rose neuron model is proposed in this paper. The security analysis confirmed that enryption algorithm is well.
Virtual double-well potential for an underdamped oscillator created by a feedback loop
Authors: Dago Salambô , Pereda Jorge , Ciliberto Sergio , Bellon Ludovic 
Published: May 2022

Abstract
Virtual potentials are a very elegant, precise and flexible tool to manipulate small systems and explore fundamental questions in stochastic thermodynamics. In particular double-well potentials have applications in information processing, such as the demonstration of Landauer’s principle. Nevertheless, virtual double-well potentials had never been implemented in underdamped systems. In this article, we detail how to face the experimental challenge of creating a feedback loop for an underdamped system (exploring its potential energy landscape much faster than its over-damped counterpart), in order to build a tunable virtual double-well potential. To properly describe the system behavior in the feedback trap, we express the switching time in the double-well for all barrier heights, combining for the first time Kramer’s description, valid at high barriers, with an adjusted model for lower ones. We show that a small hysteresis or delay of the feedback loop in the switches between the two wells results in a modified velocity distribution, interpreted as a cooling of the kinetic temperature of the system. We successfully address all issues to create experimentally a virtual potential that is statistically indistinguishable from a physical one, with a tunable barrier height and energy step between the two wells.
Enhancement of transmission line model to analyze the matching section of a dielectric-loaded accelerator with sharp discontinuities
Authors: Joozdani M.Z. 
Published: May 2022

Abstract
In this paper, a compact and single-mode X-band
dielectric-loaded matching section with constant tilt angle, blended
edges, and two discontinuities at both ends is analyzed by the
transmission line model. This matching section is designed as a
high-power injection coupler to a dielectric-loaded accelerating
structure (DLA). Although the transmission line model is a powerful
tool for single-mode structures, because of radial inhomogeneity and
lack of single value for characteristic impedance in
dielectric-loaded structures, this method is not applicable in
non-uniform dielectric-loaded structures. To solve this problem, it
is shown that a dielectric-loaded waveguide (DLW) can be modeled by
a dielectric-filled waveguide (DFW) with the same parameters of the
phase constant, power flow, and dielectric loss. The characteristic
impedance of a dielectric-filled waveguide can be determined by
three structural parameters of the real and imaginary parts of the
dielectric material and inner radius. These structural parameters
can be found by solving a non-linear equation system made by
equality of the parameters of the dielectric-loaded and
dielectric-filled waveguides. To analyze the matching section, it is
stratified to low thickness and uniform DLWs in the propagation
direction and every segment is substituted by its equal DFW
model. However, because of sharp variation in dielectric region at
two ends of the flared section, solving the non-linear equation
system is difficult at these points due to the lack of a proper
initial point for the answer. Therefore, two virtual sections are
added at the discontinuities to smoothen the variation of the
dielectric region. Then, the total transmission matrix and
scattering matrix parameters can be obtained without considering the
added virtual sections. Moreover, the matching section is simulated
by a full-wave electromagnetic software and the results of the
scattering matrix parameters are compared with the ones of the
proposed method. It is shown that there is a good agreement between
the total behavior of the simulation and analytical results and the
proposed method has acceptable accuracy.
Feasibility study of imaging with tissue-scattered triple-γ coincidence events in Compton-PET
Authors: Ghosh S. , Das P. 
Published: May 2022

Abstract
The objective of the present work is to study Compton-PET
imaging with single scattered (in tissue) data using a non-pure beta
emitter (44Sc). Such radioisotopes are advantageous because of
the extra gamma radiation to be used in triple-γ
coincidences. Utilizing the single scattered events in conjunction
with an additional gamma (1157 keV) emitted from 44Sc,
provided us with an opportunity to obtain the direct images of the
source activity distribution. The idea presented here is unique
because there is hardly any imaging research with tissue-scattered
data in the literature, especially for a Compton-PET system using a
non-pure beta emitter. Initially, we described the locus of
tissue-scattered point as a prolate spheroid surface or spindle
toroid, which became two intersection points after using Compton
cones from both ends of 511 keV photon detections. We considered a
human-sized Compton-PET system of two types — (i) ideal and
(ii) state-of-art scanner — depending on the energy and timing
resolutions of detectors. The list-mode data were generated via GATE
simulations. The appropriate trigger logic was applied using the
two-window method to separate the events corresponding to single
tissue-scattered and true (unscattered) coincidences. The imaging
involves estimating the annihilation point for each
triple-coincidence event using Compton cone of 1157 keV gamma and
time-of-flight information for the 511 keV. Thus, we directly
obtained images of the activity distribution without using any
reconstruction algorithm. They turned out indeed meaningful,
establishing our feasibility study. For quality assessment, we
compared the full-width-half-maximum (FWHM) of the intensity
profiles of various images. For ideal scanner, for instance, the
FWHM for the tissue-scattered image was almost double of that for
the unscattered one. Although the image quality was not all that
good, but we expected it because of physics-based uncertainties
involved in the tissue-scattered imaging. Nonetheless, separate
assessments of the underlying activity from two independent data
sets — one from single tissue-scattered, another from the usual
true coincidences — could certainly improve image interpretation
in medical diagnosis.
A drug-responsive multicellular human spheroid model to recapitulate drug-induced pulmonary fibrosis
Authors: Saygili Ecem , Devamoglu Utku , Goker-Bagca Bakiye , Goksel Ozlem , Biray-Avci Cigir , Goksel Tuncay , Yesil-Celiktas Ozlem 
Published: May 2022

Abstract
Associated with a high mortality rate, pulmonary fibrosis (PF) is the end stage of several interstitial lung diseases. Although many factors are linked to PF progression, initiation of the fibrotic process remains to be studied. Current research focused on generating new strategies to gain a better understanding of the underlying disease mechanism as the animal models remain insufficient to reflect human physiology. Herein, to account complex cellular interactions within the fibrotic tissue, a multicellular spheroid model where human bronchial epithelial cells incorporated with human lung fibroblasts was generated and treated with bleomycin (BLM) to emulate drug-induced PF. Recapitulating the epithelial-interstitial microenvironment, the findings successfully reflected the PF disease, where excessive alpha smooth muscle actin and collagen type I secretion were noted along with the morphological changes in response to BLM. Moreover, increased levels of fibrotic linked COL13A1, MMP2, WNT3 and decreased expression level of CDH1 provide evidence for the model reliability on fibrosis modelling. Subsequent administration of the Food and Drug Administration approved nintedanib and pirfenidone anti-fibrotic drugs proved the drug-responsiveness of the model.