bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic skyrmions generation and control in FePt nanoparticles through shape and magnetocrystalline anisotropy variation: a finite elements method micromagnetic simulation study
Authors: Stavrou Vasileios D , Gergidis Leonidas N 
Published: April 2021

Abstract
Magnetic skyrmions created during magnetization reversal in cylindrical, reuleaux and polygon-based magnetic nanoparticles with perpendicular magnetocrystalline anisotropy (MCA) similar to that of partially chemically ordered FePt were studied using finite elements method micromagnetic simulations. Néel chiral stripes, horseshoe, labyrinth skyrmionic textures along with multiple skyrmions were unveiled in different systems generated by the variation of the MCA magnitude and the nanoparticles geometrical shape. These skyrmionic textures under certain conditions can be stable in a range of external magnetic fields and for different MCA values. Simulations revealed the inherent relation of skyrmionic states with nanoparticle geometry and the energy differences between successive external field values observed during the magnetization reversal process. Energetical transitions from non-skyrmionic to skyrmionic and from skyrmionic to different skyrmionic states were quantified and associated with the individual anisotropy, exchange and demagnetization energy contributions for the nanoparticles studied. Finally, the diameters of Néel type skyrmions created through the nanoparticle shape variation were reported for different MCA and external magnetic field values.
Ce–Dy substituted barium hexaferrite nanoparticles with large coercivity for permanent magnet and microwave absorber application
Authors: Todkar G B , Kunale R A , Kamble R N , Batoo Khalid M , Ijaz M F , Imran A , Hadi M , Raslan E H , Shirsath Sagar E , Kadam R H 
Published: April 2021

Abstract
M-type barium hexaferrites (BaM) with the substitution of Ce–Dy ions were synthesized using the sol-gel auto-ignition method. The prepared materials were explored for their application as a permanent magnet and microwave absorbing material. The structural properties, phase evaluation, micro-strain, morphological analysis, magnetic behaviour, microwave absorbing properties and optical properties were studied by employing various techniques. The structural parameters and phase identification obtained by Rietveld refinement confirmed the formation of an M-type hexaferrite structure for pure BaM, whereas Ce–Dy substitution induced secondary phases of cubic CeO2 and ortho DyFeO3. Crystallite size obtained from Williamson–Hall plots increased from 27.1 nm to 30.8 nm with the introduction of Ce–Dy ions in BaM. The nanocrystalline nature of the prepared samples was confirmed using scanning and transmission electron microscopy techniques. Fourier transform infrared spectra of all the samples were recorded in the wavenumber range of 400–4000 cm−1 and also supported the x-ray diffraction findings by confirming the formation of samples with hexaferrite structures. Coercivity of the BaM hexaferrites improved from 4430 to 5721 Oe with the Ce–Dy substitution. A Ce–Dy substituted BaM hexaferrite sample of 3 mm thickness showed a maximum reflection loss of −16.3 dB around 16.7 GHz. Permittivity and permeability studies were carried out to understand the microwave absorption behaviour.
FAMOUS: a fast instrumental and computational pipeline for multiphoton microscopy applied to 3D imaging of muscle ultrastructure
Authors: Lefort Claire , Chalvidal Mathieu , Parenté Alexis , Blanquet Véronique , Massias Henri , Magnol Laetitia , Chouzenoux Emilie 
Published: April 2021

Abstract
We present a new instrumental and computational pipeline named FAMOUS: fast algorithm for three-dimensional (3D) multiphoton microscopy of biomedical structures. This pipeline rests on a MPM strategy combined with an original 3D post-processing computational approach. In the present work, FAMOUS approach is devoted to the 3D imaging of the myosin assembly of the ultrastructure of a whole striated skeletal muscle unsliced. Raw recordings of second harmonic generation (SHG) from myosin and instrumental point-spread functions (PSF) are led simultaneously all along the unsliced muscle depth. This procedure highlights a space-variant distortion of the PSF and the SHG signals, and an optical degradation of the axial resolution increasing with imaging depth resulting from the optical heterogeneity of the muscle structure. A 3D mathematical modelling of the PSF, relying on the recent FIGARO method, evaluates and models the depth-variant evolution of the optical distortions. Then, the fast image deblurring algorithm BD3MG is employed to correct those non-stationary distortions all along the sample, thanks to a sounded regularized inverse problem methodology. This leads to the pipeline called FAMOUS, whose performance are highlighted for the optimization of the axial information of myosin structure, whose dimensions are close to the axial resolution limit. For the first time, the 3D organization of the myosin in skeletal muscle is visually shown from an unsliced whole muscle, starting with a solution of optical microscopy. The axial visualization of this organization presently disclosed were never shown until now without a preliminary procedure of sample slicing and labelling. Our original solution FAMOUS delivers a new point of view of this biological structure in the 3D and especially in the optical axis. Image information theoretically expected are now revealed visually in the optical axis for the first time in a whole organ unsliced and label free.
Out-of-time-ordered correlators and the Loschmidt echo in the quantum kicked top: how low can we go?
Authors: PG Sreeram , Madhok Vaibhav , Lakshminarayan Arul 
Published: April 2021

Abstract
The out-of-time-ordered correlators (OTOCs) and the Loschmidt echo are two measures that are now widely being explored to characterize sensitivity to perturbations and information scrambling in complex quantum systems. Studying few qubits systems collectively modeled as a kicked top, we solve exactly the three- and four-qubit cases, giving analytical results for the OTOC and the Loschmidt echo. While we may not expect such few-body systems to display semiclassical features, we find that there are clear signatures of the exponential growth of OTOC even in systems with as low as four qubits in appropriate regimes, paving way for possible experimental measurements. We explain qualitatively how classical phase space structures like fixed points and periodic orbits have an influence on these quantities and how our results compare to the large-spin kicked top model. Finally we point to a peculiar case at the border of quantum–classical correspondence which is solvable for any number of qubits and yet has signatures of exponential sensitivity in a rudimentary form.
Quantum phases and thermodynamics of a frustrated spin-1/2 ladder with alternate Ising–Heisenberg rung interactions
Authors: Saniur Rahaman Sk , Sahoo Shaon , Kumar Manoranjan 
Published: April 2021

Abstract
We study a frustrated two-leg spin ladder with alternate isotropic Heisenberg and Ising rung exchange interactions, whereas, interactions along legs and diagonals are Ising-type. All the interactions in the ladder are anti-ferromagnetic in nature and induce frustration in the system. This model shows four interesting quantum phases: (i) stripe rung ferromagnetic (SRFM), (ii) stripe rung ferromagnetic with edge singlet (SRFM-E), (iii) anisotropic antiferromagnetic (AAFM), and (iv) stripe leg ferromagnetic (SLFM) phase. We construct a quantum phase diagram for this model and show that in stripe rung ferromagnet (SRFM), the same type of sublattice spins (either isotropic S-type or discrete anisotropic σ-type spins) are aligned in the same direction. Whereas, in anisotropic antiferromagnetic phase, both S and σ-type of spins are anti-ferromagnetically aligned with each other, two nearest S spins along the rung form an anisotropic singlet bond whereas two nearest σ spins form an Ising bond. In large Heisenberg rung exchange interaction limit, spins on each leg are ferromagnetically aligned, but spins on different legs are anti-ferromagnetically aligned. The thermodynamic quantities like specific heat C

v
(T), magnetic susceptibility χ(T) and thermal entropy S(T) are also calculated using the transfer matrix method for various phases. The magnetic gap in the SRFM and the SLFM can be noticed from χ(T) and C

v
(T) curves.
Field induced hysteretic structural phase switching and possible CDW in Re-doped MoTe2
Authors: Vasdev Aastha , Kamboj Suman , Sirohi Anshu , Mandal Manasi , Marik Sourav , Singh Ravi Prakash , Sheet Goutam 
Published: April 2021

Abstract
Novel electronic systems displaying exotic physical properties can be derived from complex topological materials through chemical doping. MoTe2, the candidate type-II Weyl semimetal shows dramatically enhanced superconductivity up to 4.1 K upon Re doping in Mo sites. Based on bulk transport and local scanning tunnelling microscopy here we show that Re doping also leads to the emergence of a possible charge density wave phase in Re0.2Mo0.8Te2. In addition, the tunnelling I–V characteristics display non-linearity and hysteresis which is commensurate with a hysteresis observed in the change in tip-height (z) as a function of applied voltage V. The observations indicate an electric field induced hysteretic switching consistent with piezoelectricity and possible ferroelectricity.
High-order simulation scheme for active particles driven by stress boundary conditions
Authors: Deußen B , Jayaram A , Kummer F , Wang Y , Speck T , Oberlack M 
Published: April 2021

Abstract
We study the dynamics and interactions of elliptic active particles in a two dimensional solvent. The particles are self-propelled through prescribing a fluid stress at one half of the fluid-particle boundary. The fluid is treated explicitly solving the Stokes equation through a discontinuous Galerkin scheme, which allows to simulate strictly incompressible fluids. We present numerical results for a single particle and give an outlook on how to treat suspensions of interacting active particles.
Quantum magnetotransport oscillations in graphene nanoribbons coupled to superconductors
Authors: Takagaki Y 
Published: April 2021

Abstract
Magnetotransport properties of zigzag and armchair graphene nanoribbons that are in contact with superconductors are investigated using a tight-binding model. The cyclotron orbital motion together with the quantum interference under the coexistence of Andreev and normal reflections gives rise to a number of oscillations in characteristic magnetic-field regimes when the superconducting coupling is weak. The oscillations become irregular and/or suppressed as the coupling is made strong. The period of the oscillations differs from that when a nonrelativistic two-dimensional electron gas is employed rather than the graphene sheet. The modifications of the oscillations are attributed to the phase shift associated with the reflection from the graphene–superconductor interface. The presence of a magnetic field suppresses the quantum blocking of Andreev transmission, which occurs for the edge mode of zigzag nanoribbons, in the same way regardless of it being induced by the Andreev retro- or specular reflection.
The optimisation of paediatric CT examinations in Scotland: phase one; benchmarking current performance
Authors: Worrall Mark , MacDonald Nicola , Gillen Rebecca , Hince Andrew , Hampson Lee , Duguid Rebecca , McCallum Stephen , Gentle David 
Published: April 2021

Abstract
To benchmark the dose from paediatric head and chest examinations on computed tomography (CT) scanners throughout Scotland, to identify scanners that may require optimisation and to provide optimisation advice based on the protocols from better performing scanners. Anthropomorphic phantoms corresponding to 1, 5 and 10 year olds were sent to 50 CT scanners around Scotland. Head and chest examinations were undertaken by local staff using local techniques on each scanner with each phantom, and details of the protocols used were recorded. Computed tomography dose index (CTDI)vol and dose length product (DLP) were recorded post-scan. There is a significant variation in performance throughout Scotland. For head examinations, the highest DLP is 13 times the lowest for an equivalent sized phantom. For chest examinations, the highest is 128 times the lowest for an equivalent sized phantom. The wide range of CT dose measurements indicates the potential for variation in image quality across Scotland. Feedback has been provided to all participating sites on their individual results compared to the national data set. Specific feedback was provided where relevant on potential considerations for optimisation. Scanners that may be undertaking paediatric CT head and chest examinations in a sub-optimal manner throughout Scotland have been identified along with those aspects of a scan protocol that are most likely to lead to sub-optimal performance.
Virtual-sample-based defect detection algorithm for aluminum tube surface
Authors: Lang Ning , Wang Decheng , Cheng Peng , Zuo Shanchao , Zhang Pengfei 
Published: April 2021

Abstract
A surface defect is an important factor that affects product quality. However, due to the large differences in area of different surface defects, and noise on various surfaces, defect detection is challenging. The convolutional neural network (CNN)-based methods recently developed for defect detection produced higher recognition rates than traditional methods. However, they are typically trained using a supervised learning strategy and large defect sample sets which limits the practical use of these algorithms. This study proposes a novel virtual sample generation algorithm to solve the problem of insufficient defective samples and time-consuming manual annotation in current CNN-based defect detection algorithms. Next, an improved domain-adversarial neural network is proposed, which is trained on virtual and actual datasets to achieve unsupervised learning. Considering the imbalance in actual dataset, algorithm accuracy is improved by changing the proportions of defective and non-defective samples in the virtual sample set, and this strategy is experimentally verified. The performance of the proposed algorithm is compared with several top-performing defect inspection algorithms. The experimental results show that the proposed algorithm exhibits superior performance when compared to other algorithms.
Chiro-optical response of a wafer scale metamaterial with ellipsoidal metal nanoparticles
Authors: Suchitta Aakansha , Suri Priyanka , Xie Zhuolin , Xu Xianfan , Ghosh Ambarish 
Published: April 2021

Abstract
We report a large chiro-optical response from a nanostructured film of aperiodic dielectric helices decorated with ellipsoidal metal nanoparticles. The influence of the inherent fabrication variation on the chiro-optical response of the wafer-scalable nanostructured film is investigated using a computational model which closely mimics the material system. From the computational approach, we found that the chiro-optical signal is strongly dependent on the ellipticities of the metal nanoparticles and the developed computational model can account for all the variations caused by the fabrication process. We report the experimentally realized dissymmetry factor ∼1.6, which is the largest reported for wafer scalable chiro-plasmonic samples till now. The calculations incorporate strong multipolar contributions of the plasmonic interactions to the chiro-optical response from the tightly confined ellipsoidal nanoparticles, improving upon the previous studies carried in the coupled dipole approximation regime. Our analyzes confirm the large chiro-optical response in these films developed by a scalable and simple fabrication technique, indicating their applicability pertaining to manipulation of optical polarization, enantiomer selective identification and enhanced sensing and detection of chiral molecules.
Development of a multifunctional system based on CoFe2O4@polyacrylic acid NPs conjugated to folic acid and loaded with doxorubicin for cancer theranostics
Authors: Arkaban Hassan , Khajeh Ebrahimi Ahmad , Yarahmadi Ali , Zarrintaj Payam , Barani Mahmood 
Published: April 2021

Abstract
In this work, a multifunctional theranostic nanocomposite based on CoFe2O4@polyacrylic acid (PAA)-Folic Acid (FA) Doxorubicin (Dox)load NPs was designed for the multifunctional cancer treatment. Several techniques such as TEM, DLS, ζ-potential, vibrating sample magnetometer, XRD, and UV−Vis spectrophotometer were applied for investigating physicochemical properties of the nanosystem. The percentage of the loaded drug, loading efficiency, in vitro release (pH 5.4 and 7.4), in
vitro MRI measurements, and MTT assay (4T1 and 9A9 cell lines) were evaluated. Results showed that the percentage of loaded drug and loading efficiency was 53.33 ± 3.5 and 80.00 ± 5.3%, respectively, showing the system’s high ability for Dox encapsulation. Release study showed that Dox loaded in the CoFe2O4@PAA-FA(Dox)load NPs released faster at pH 5.4 than pH 7.4. In vitro, MRI measurements confirmed that CoFe2O4@PAA NPs could be used as a contrast agent in MRI measurements with r
2 = 18.2 mM−1 s−1. MTT assay demonstrated the biocompatibility of NPs, also showed a more efficient therapeutic effect for CoFe2O4@PAA-FA(Dox)load NPs than free Dox and CoFe2O4@PAA(Dox)load NPs.
Fabrication of graphene: CdSe quantum dots/CdS nanorod heterojunction photodetector and role of graphene to enhance the photoresponsive characteristics
Authors: Perumal Veeramalai Chandrasekar , Kollu Pratap , Lin Guochen , Zhang Xiaoming , Li Chuanbo 
Published: April 2021

Abstract
Integration of graphene with semiconducting quantum dots (QDs) provides an elegant way to access the intrinsic properties of graphene and optical properties of QDs concurrently to realize the high-performance optoelectronic devices. In the current article, we have demonstrated the high-performance photodetector based on graphene: CdSe QDs/CdS nanorod heterostructures. The resulting heterojunction photodetector with device configuration ITO/graphene: CdSe/CdS nanorods/Ag show excellent operating characteristics including a maximum photoresponsivity of 15.95 AW−1 and specific detectivity of 6.85 × 1012 Jones under 530 nm light illumination. The device exhibits a photoresponse rise time of 545 ms and a decay time of 539 ms. Furthermore, the study of the effect of graphene nanosheets on the performance enhancement of heterojunction photodetector is carried out. The results indicate that, due to the enhanced energy transfer from photoexcited QDs to graphene layer, light absorption is increased and excitons are generated led to the enhancement of photocurrent density. In addition to that, the graphene: CdSe QDs/CdS nanorod interface can facilitate charge carrier transport effectively. This work provides a promising approach to develop high-performance visible-light photodetectors and utilizing advantageous features of graphene in optoelectronic devices.
Photo generated charge transport studies of defects-induced shuttlecock-shaped ZnO/Ag hybrid nanostructures
Authors: Choudhary Siddharth , Vashisht Garima , Malik Rakesh , Dong Chung-Li , Chen Chi-Liang , Kandasami Asokan , Annapoorni S 
Published: April 2021

Abstract
We report the stimulating effects of interfacial charge transfer process between spherical Ag nanoparticles and shuttlecock-shaped ZnO nanostructures observed by UV−visible spectroscopy and x-ray absorption spectroscopy. In specific, ZnO nanorods and shuttlecock-shaped ZnO/Ag nanostructures were developed using a simple chemical colloidal method and characterized for structural variations using XRD. The observed red shift in plasmonic peak and the increase in Urbach energy signify interfacial interactions and increased randomness in the hybrid ZnO/Ag nanostructures. Simultaneously, the enhanced intensity of deep-level emission in the ZnO/Ag hybrid suggests the increased recombination rate of electron-hole pairs. The red and blue emissions evolving with temperature subsequently suggests the presence of oxygen vacancies or zinc interstitials in the system. The decrease in intensities and emerging features in O K-edge and Zn L-edge indicates the charge transfer from Ag to ZnO at the interface of ZnO/Ag hybrids. Moreover, the differences in absorption edges with alternating light on/off conditions were analyzed for the exploitation of this ZnO-based system in various applications.
Controllable morphology of electrospun nanofiber membranes with tunable groove structure and the enhanced filtration performance for ultrafine particulates
Authors: Lou Yaoyuan , Ding Shanshan , Wang Bin , Wang Jie , Sun Qing , Jin Xu , Li Xiuyan 
Published: April 2021

Abstract
As researchers are striving to develop high-performance filtration membranes with hierarchical micro/nano structures, the challenges and costs of processing often limit creative innovation. Here, we propose a polyethersulfone/polyacrylonitrile (PES/PAN) nanofiber membrane with groove structure by electrospinning and facile post-processing. The resulted membrane can form a groove structure on the surface of the fiber after being soaked in chloroform, thereby increasing the collision probability and extending the residence time for ultrafine particulates and improving the filtration efficiency. The groove structure can be attributed to the solubility of PES constituent in chloroform, while PAN constituent will not be dissolved, thus forming a high-performance nanofiber membrane with high filtration efficiency (ca. 99.54%) and withstand pressure drop (ca. 133.9 Pa) for dioctyl phthalate aerosol particles with diameter of 0.3 μm. The results show that this convenient and low-cost fabrication technology can be used to prepare high-performance nanofiber membrane based air filters that have broad application prospects in respiratory protective equipment.
Oxygen-rich PdSnCu nanocrystals with particle connection features as enhanced catalysts for ethanol oxidation reaction
Authors: Xie Jian , Yang Hui , Dong Qizhi , Qin Qian , Hu Chao , Yu Gang 
Published: April 2021

Abstract
Most electrocatalysts show a high mass and special activity during the ethanol oxidation reaction, but those still suffer from limited stability, finite renewable capability and poor anti-poisoning durability. Furthermore, the reliable structure and appropriate composition of catalysts are fairly associated with the electrocatalysis performance. Herein, we report the development of trimetallic Pd61Sn34Cu5 nanocrystals (NCs) whose rough surfaces are rich in step atoms and coupled with abundant of SnOx and CuO, which may effectively boost reaction activity and rapidly remove carbonaceous intermediate, respectively. Under the tuning on the composition, the defect rich Pd61Sn34Cu5 NCs exhibit elevated electrocatalysis activity and durability for ethanol oxidation reaction with an optimized mass activity (1.26 A

mg

Pd

−
1

) and specific activity (10.6 mA cm−2), which is about 2.21 and 2.58 times greater than that of the commercial Pd/C catalyst (0.57 A

mg

Pd

−
1

and 4.1 mA cm−2).