bluuebunny/crossref_metadata_2025 huggingface dataset:
Demonstration of Double Aortic Arch in a 21 Weeks Primigravida by Color Spatiotemporal Image Correlation Rendering Technique
Authors: Dey Shankar
Published: October 2023

Fetal double aortic arch (DAA) is a rare congenital arch anomaly characterized by the presence of two aortic arches instead of the normal single arch. DAA is an uncommon finding during routine fetal echocardiography.

Prenatal ultrasound detection of fetal DAA is crucial for early identification and appropriate management of affected fetuses. Despite the challenges and limitations, advancements in imaging technology and expertise have improved diagnostic accuracy.

Four-dimensional (4D) ultrasound provides a volumetric representation of the fetal structures. It allows for better visualization and assessment of complex anatomical abnormalities, including DAA. With 4D imaging, the sonographer can manipulate the image, rotate it, and view it from different angles, aiding in the identification of the double arch anomaly

This is a case of double aortic arch diagnosed with the spatiotemporal image correlation (STIC) technique of 4D ultrasound using color Doppler.
Democratic self-government and the algocratic shortcut: the democratic harms in algorithmic governance of society
Authors: Alnemr Nardine
Published: October 2023

Algorithms are used to calculate and govern varying aspects of public life for efficient use of the vast data available about citizens. Assuming that algorithms are neutral and efficient in data-based decision making, algorithms are used in areas such as criminal justice and welfare. This has ramifications on the ideal of democratic self-government as algorithmic decisions are made without democratic deliberation, scrutiny or justification. In the book Democracy without Shortcuts, Cristina Lafont argued against “shortcutting” democratic self-government. Lafont’s critique of shortcuts turns to problematise taken-for-granted practices in democracies that bypass citizen inclusion and equality in authoring decisions governing public life. In this article, I extend Lafont’s argument to another shortcut: the algocratic shortcut. The democratic harms attributable to the algocratic shortcut include diminishing the role of voice in politics and reducing opportunities for civic engagement. In this article, I define the algocratic shortcut and discuss the democratic harms of this shortcut, its relation to other shortcuts to democracy and the limitations of using shortcuts to remedy algocratic harms. Finally, I reflect on remedy through “aspirational deliberation”.
A multifunctional hydrogel-based strain sensor and triboelectric nanogenerator for running monitoring and energy harvesting
Authors: Zhang Yu , He Xiaoyan , Xu Chuanming
Published: October 2023

Recently, flexible wearable electronics for human running posture monitoring and human energy harvesting have attracted widespread attention. Hence, we design a mixed type conductive hydrogel based on polyvinyl alcohol, cotton paper, graphite oxide, and MXene, named PCGM hydrogel. Furthermore, the PCGM hydrogel can act as the PCGM-based strain sensor and triboelectric nanogenerator (P-TENG) for running posture monitoring and mechanical energy harvesting. The PCGM-based strain sensor has two sensing linear regions: The pressure sensitivity is 0.0164 kPa−1 in the low pressure region (0–16 kPa), whereas it is 0.002 86 kPa−1 in the high pressure region (16–120 kPa). To achieve comprehensive health monitoring of runners, the PCGM-based strain sensors can be installed on human joints and facial skin to monitor human posture and facial expressions. The PCGM hydrogel can be combined with a polytetrafluoroethylene film to form a P-TENG device for mechanical energy harvesting. The P-TENG maximum output power can reach 135 µW with a 30 MΩ load. The short-circuit current (Isc), open-circuit voltage (Voc), and transfer charge (Qsc) of P-TENG can reach 10.36 µA, 229.85 V, and 49.24 nC, respectively. This research provides an effective approach for human-running motion monitoring by using multifunctional flexible devices.
Low-temperature enhanced OFF-state telegraph noise in defect engineered ReRAMs
Authors: Alagoz H. S. , Egilmez M. , Jung J. , Chow K. H.
Published: October 2023

The OFF-state retention characteristics of Pt/NiOx–(Ar)/NiOx–(Ar + O2)/Pt stacking resistive random access memory structures were measured as a function of temperature between 300 and 190 K. The devices show random telegraph noise effects whose noise amplitude increases upon lowering the temperature. Interestingly, the application of forward and reverse biases produces up and downresistance jumps. These results present important insights into the thermally activated charge trapping/de-trapping phenomenon that is responsible for resistance fluctuations.
‘I think we just do it once and leave it …’ The collection and utility of family health history in general practice in Aotearoa New Zealand: a qualitative study
Authors: Jefferies R. , Wilcox P. , Paringatai K. , Stubbe M. , Grainger R. , Dowell A. , Filoche S. K.
Published: October 2023

Introduction The value of family health history as a means to understanding health risk has been long known. Its value in a precision medicine context is also now becoming apparent. General practitioners (GPs) are considered to play a key role in the collection, and investigation, of family health history, but it remains widely reported as being both poorly and infrequently undertaken. Little is known about this practice in Aotearoa New Zealand (NZ). Aim This study aimed to explore current practices in relation to the ascertainment of family health history, with a view towards precision medicine. Methods Semi-structured interviews were conducted with 10 GPs recruited from one urban area of NZ. The interviews were subjected to a thematic analysis. Results Family health history information was used to varying degrees in four areas – risk ascertainment, patient engagement with a diagnosis, social context and building relationships. Patient cultural considerations were rarely mentioned. Reliability of information provided by patients, resource constraints, context driven consults and electronic health record limitations are potential indicators of current limits of family health history. Discussion Our findings present a baseline of current practice and echo larger studies from overseas. As precision medicine is not yet routine, a unique opportunity exists for consideration to be given to establishing specific roles within the NZ health system to enable equitable practice of, and subsequent health gains from, the use of family/whānau health history information as part of precision medicine.
The deubiquitinase ZRANB1 is an E3 ubiquitin ligase for SLC7A11 and regulates ferroptotic resistance
Authors: Huang Shan , Zhang Qimin , Zhao Manyu , Wang Xing , Zhang Yilei , Gan Boyi , Zhang Peijing
Published: October 2023

The dependency of cancer cells on iron increases their susceptibility to ferroptosis, thus providing new opportunities for patients with treatment-resistant tumors. However, we show that lipid peroxidation, a hallmark of ferroptosis, was found in various areas of patient samples, indicating the potential resistance of ferroptosis. Using whole deubiquitinases (DUBs) sgRNA screening, we found that loss of ZRANB1 confers cancer cell resistance to ferroptosis. Intriguingly, functional studies revealed that ZRANB1 ubiquitinates and represses SLC7A11 expression as an E3 ubiquitin ligase and that ZRANB1 inhibits glutathione (GSH) synthesis through SLC7A11 degradation, leading to elevated lipid peroxidation and ferroptosis. Deletion of the region (residues 463–584) abolishes the E3 activity of ZRANB1. Moreover, we show that ZRANB1 has lower expression in tumors, which is positively correlated with lipid peroxidation. Collectively, our results demonstrate the role of ZRANB1 in ferroptosis resistance and unveil mechanisms involving modulation of E3 ligase activity through an unconventional catalytic domain.
A two-channel ultrasonic flowmeter based on AlN piezoelectric micromachined ultrasonic transducers arrays with improved cross-correlation method
Authors: Shi Linjin , Qu Mengjiao , Lv Dongze , Liu Weiting , Xie Jin
Published: October 2023

This paper presents a highly accurate two-channel ultrasonic flowmeter based on AlN piezoelectric micromachined ultrasonic transducers (PMUTs) to measure flow rate in small-diameter pipes (9.6 mm). The ultrasonic transducers consist of four 10 by 10 PMUTs arrays with resonant frequency of 1 MHz in air. The ultrasonic transducers are excited by continuous sine voltage, and the transmitted and received signals are subjected to cross-correlation operation to obtain the time delay of the ultrasonic wave in the liquid. A dual-channel design of the flowmeter can reduce measurement errors by taking the average value. To reduce errors in the cross-correlation operation, an iterative algorithm is proposed, which effectively improves the measurement accuracy. The flowmeter is evaluated in flow range of 3.5–10 l min−1, and has a small relative error of 0.7%.
A compact low-frequency sound absorption metastructure realized by resonators with wavy bending necks
Authors: Zhang Songyi , Song Ailing , Wang Shuai , Yu Xinhai
Published: October 2023

In this work, a compact low-frequency sound absorption metastructure composed of multiple resonators with embedded wavy bending necks is proposed. By arranging this metastructure in parallel and optimizing the parameters, it exhibits excellent broadband sound absorption capability in low-frequency range and has a much more compact volume. Compared with the traditional resonators, an individual resonator of this metastructure can move down the absorption frequency about 120 Hz while maintaining the same thickness. Furthermore, different resonator units are combined into a sound absorption array by employing appropriate design techniques. We first built a small metastructure composed of four units to demonstrate the correctness and accuracy of our design method. Both theoretical models and finite element simulation models are built and experimental results show good agreement between them. To achieve the same absorption value and frequency range, the thickest resonator in the traditional resonator array must be 30% thicker than the one in the wavy bending neck resonator array, which means the overall size of the structure is 30% larger. Following this design method, perfect sound absorption within the frequency range of 248 Hz–420 Hz is achieved with a compact volume of 53 mm in radius and 47 mm in height. The design strategy presents a new approach to achieve perfect broadband low-frequency sound absorption.
Structural, dielectric, and optical properties based on spinel ferrite (Mn0.5Fe1.5Mg0.5Ni0.5O4) nanoparticles filler reinforced PVA for optoelectronic, laser CUT-OFF filters and energy storage devices
Authors: Rabiea E A , Abouhaswa A S , Abomostafa H M
Published: October 2023

The fabrication of polymer nanocomposites with specialized traits is gaining popularity across the world due to novel added qualities. In this work we used a flash auto-combustion method to prepare Mn0.5Fe1.5Mg0.5Ni0.5O4 nanoparticles and the casting method to prepare Mn0.5Fe1.5Mg0.5Ni0.5O4/PVA nanocomposite polymer films with doping of nanoparticles various from 1–5 wt.%. The effect of Mn0.5Fe1.5Mg0.5Ni0.5O4 nanoparticles addition on the structural, optical, and dielectric characteristics of nanocomposite polymer films was analyzed. The structural properties were studied using x-ray diffraction pattern, high resolution transmission electron microscope, Fourier transform infrared, and field emission scanning electron microscope. The effects of nanoparticles doping on ac conductivity, electric modulus, impedance, and dielectric constant were investigated. It shows that Mn0.5Fe1.5Mg0.5Ni0.5O4/PVA nanocomposite films have higher values of permittivity and ac conductivity than PVA and exhibit lower values of dielectric loss, electric modulus, and impedance. The optical properties showed the indirect optical decreased from 4.8 to 4.4 eV. According to the experimental results, these nanocomposite polymer films show promise for laser CUT-OFF filters and energy storage devices.
Table-like magnetocaloric effect due to field-induced inter-cluster interactions in Eu0.5Sr0.5MnO3–EuMnO3 composites
Authors: Akram Wasim , de h-Óra Muireann , Bansal Manisha , Mukhopadhyay Rajatava , MacManus-Driscoll Judith , Maity Tuhin
Published: October 2023

The table-like behavior of the magnetic entropy change is generally observed in rare-earth-based alloys (e.g. La(Fe,Si)13, Gd50Co45Fe5, Gd56Ni15Al27Zr2, Gd

(
1
−
x
−
y
)

Co
x
Al
y
etc). Here, we report similar table-like behavior in a bulk perovskite Eu0.5Sr0.5MnO3–EuMnO3 composite system with a working temperature span of ∼80 K for a field change of ∼70 kOe. AC susceptibility and time-dependent DC magnetization relaxation measurements confirm the presence of interacting ferromagnetic clusters with a Vogel–Fulcher freezing temperature of

T
0

∼

42.7 K. The Langevin function fittings of the isothermal magnetization curves show a non-monotonous variation of cluster size with temperature. We propose a model for the high-field dependency of the ferromagnetic cluster coupling in the composite system. This widens the transition temperature region of long-range order formation and hence gives rise to the table-like magnetocaloric effect in Eu0.5Sr0.5MnO3–EuMnO3 composite systems.
Flexible dielectric spacer with tunable dielectric properties for metamaterial absorber application
Authors: Chaudhary Kajal , Malik Sudha , Singh Gaganpreet , Bhattacharya Sudeb , Ramkumar J , Ramakrishna S Anantha , Srivastava Kumar Vaibhav
Published: October 2023

The development of a flexible and robust metamaterial absorber is a great motivation for the new generation of microwave absorbers covering any conformal shape. Ceramic–polymer composites with variable dielectric constant within the microwave frequencies are proposed as a flexible middle dielectric spacer (MDS) layer to provide an additional degree of design freedom for metamaterial absorber applications. By varying the dielectric constant of the MDS layer, the resonance band of the metamaterial absorber can be tuned while retaining a low profile in addition to enhancing its electromagnetic performance for transverse magnetic (TM) polarized waves. To formulate these composites, tetragonal structured barium titanate (BaTiO3) powder is selected as an excellent candidate when mixed with elastomer polydimethylsiloxane (PDMS), resulting in high mechanical strength substrates. Experimentally, samples with a range of dielectric permittivity from 2.81 to 5.67 were obtained for a 0%–20% volume fill fraction of BaTiO3 in PDMS. The obtained dielectric permittivities are consistent with the Bruggeman effective medium theory. Utilizing an optimized composition (10% BaTiO3), resulting in

ϵ

r

 = 4 substrate, an X-band flexible absorber is designed and fabricated to absorb more than 90% of incident electromagnetic waves within a frequency band of 8.16–12.12 GHz.
Excitonic effects on the optical spectra of TiB2 nanosheets
Authors: Sharma Ashish , Thakur Anupma , Rangra V S
Published: October 2023

Two-dimensional (2D) transition metal borides, have recently attracted tremendous interest and become an emerging class of 2D materials due to their intriguing properties. We report systematic investigation of stability, electronic properties and optical activity of 2D-TiB2 nanosheets using first-principles calculations. By combining elastic and phonon-dispersion calculations, we substantiated the mechanical and dynamic stability of 2D-TiB2 nanosheets. Our results of elastic calculations reveal that addition of an extra layer destroys the auxetic behaviour of monolayer (ML) 2D-TiB2 with significant reduction in the brittleness. Further, based on the spin-polarised electronic structure calculations, we find that a low-dimensional metallic state of ML can be achieved by tuning the distance between the titanium and boron layers. The calculations clearly reveal that metallic nature does not destroys the auxetic behaviour of ML. Subsequently, we investigated the optical response of 2D-TiB2 nanosheets (ML and bilayer (BL)) at the level of density functional theory and many-body perturbation theory. The results obtained by solving Bethe–Salpeter equation (GW+BSE formalism) shows that excitonic effects causes a slight blue-shift in the absorption spectra of the nanosheets with ML being optically active with sharp peaks in infrared (IR) and ultraviolet (UV) regions while BL shows the reduced optical activity across wide range of photon energies spanning the near-IR to UV region. In addition, electronic polarisability of the nanosheet decreases with addition of another layer in ML 2D-TiB2. Further investigation of transition probabilities clearly indicates that the response of ML at Dirac point is tunable by spin–orbital coupling effects which makes these nanosheets promising for spintronic applications. The BL exhibits distinct electronic, and optical properties compared to ML. Our study unravels the structural, elastic, electronic, and optical properties of 2D-TiB2 nanosheets and suggests them as promising candidate for variety of optoelectronic and spintronic applications.
An image zooming method based on the coupling threshold in the wavelet packet transform domain
Authors: Liu Chenhua , Wang Anhong
Published: October 2023

Aiming at the problem of blurring edge and detail information in the process of image zooming, this paper proposes a new method of image zooming based on wavelet packet transform by combining the characteristics of anisotropic diffusion. First, the initial zoomed image with higher resolution is obtained by wavelet transform, and the wavelet packet decomposition is performed to obtain more high-frequency wavelet packet coefficients reflecting image details. Second, due to the existence of noise, the relationship between wavelet packet transform and anisotropic diffusion is obtained by studying the process of wavelet packet threshold denoising, and the expression of coupling threshold based on diffusion function is given and applied to the high-frequency wavelet packet coefficients. Finally, the original image is used as the low-frequency part after passing the soft threshold, and reconstructed with the denoised high-frequency part to obtain the final zoomed image. The traditional zooming algorithms as well as the learning-based zooming algorithms are selected for comparison. The results show that the algorithm in this paper effectively avoids the blurring of edges and details under the premise of ensuring the similarity between the zoomed image and the original image, so that the zoomed image can obtain more high-frequency information, and achieves the purpose of removing the noise as well as enhancing the detailed information of the image. The effectiveness of this paper’s algorithm in edge protection can be seen from the results of the comparison with the deep learning-based zooming algorithms.
Rolling bearing fault diagnosis model based on DSCB-NFAM
Authors: Zhao Xiaoqiang , Guo Haike
Published: October 2023

Machine learning techniques have had great success in fault diagnosis. However, the traditional machine learning methods rely heavily on manual priori knowledge leading to poor fault diagnosis results in rolling bearing fault diagnosis. Deep learning techniques can improve the accuracy of fault intelligent diagnosis with the help of automatic extraction of fault features. In this article, a method of smart fault diagnosis for rolling bearings based on depth-separable convolutional block (DSCB)-non-local feature awareness module (NFAM) is proposed. Firstly, a DSCB is constructed, which can reduce the number of parameters and effectively alleviate the gradient disappearance phenomenon. Then a NFAM is constructed to enhance the global sensing ability while adaptively adjusting the weight of each channel. Further, a feature extraction layer is constructed to extend the fault feature of the input information. Finally, a feature pyramid approach is used to fuse the extracted information for output. The validity of the suggested method is tested on both of the bearing datasets. By comparing with several mainstream intelligent diagnosis algorithms, the results of the experiments show that the proposed method has better advancement under complex conditions such as variable load and variable noise.
High accuracy key feature extraction approach for the non-stationary signals measurement based on NGO-VMD noise reduction and CNN-LSTM
Authors: Xu Fujing , Jing Ruirui , Zhang Yan , Liu Qiang , Wu Yimin A
Published: October 2023

The effective extraction of key features in non-stationary signals measurement is crucial in numerous engineering fields, including fault diagnosis, geological exploration, and state detection. To accomplish a more accurate and efficient extraction of key feature information from non-stationary signals, we design a novel approach based on variational mode decomposition (VMD) optimization by northern goshawk optimization (NGO) algorithm, convolutional neural network (CNN), and long short-term memory network (LSTM). First, NGO is used to optimize multiple intrinsic mode functions of VMD and reconstruct the signal according to the linear correlation method. Subsequently, the features of moving root mean square, moving kurtosis, and upper envelope are calculated, thereby constructing the feature matrix. Finally, the CNN-LSTM model is established with the chosen optimal hyperparameters prior to the training phase. The experimental results demonstrate that the proposed NGO-VMD-CNN-LSTM method, with a high accuracy reaching 98.22%, can more accurately extract the key information of typical non-stationary signals.
Voting models and semilinear parabolic equations
Authors: An Jing , Henderson Christopher , Ryzhik Lenya
Published: October 2023

We present probabilistic interpretations of solutions to semi-linear parabolic equations with polynomial nonlinearities in terms of the voting models on the genealogical trees of branching Brownian motion (BBM). These extend McKean’s connection between the Fisher–KPP equation and BBM (McKean 1975 Commun. Pure Appl. Math.
28 323–31). In particular, we present ‘random outcome’ and ‘random threshold’ voting models that yield any polynomial nonlinearity f satisfying

f
(
0
)
=
f
(
1
)
=
0

and a ‘recursive up the tree’ model that allows to go beyond this restriction on f. We compute several examples of particular interest; for example, we obtain a curious interpretation of the heat equation in terms of a nontrivial voting model and a ‘group-based’ voting rule that leads to a probabilistic view of the pushed-pulled transition for a class of nonlinearities introduced by Ebert and van Saarloos.
Non-invasive imaging of neural activity with magnetic detection electrical impedance tomography (MDEIT): a modelling study
Authors: Mason Kai , Aristovich Kirill , Holder David
Published: October 2023

Objectives. (1) Develop a computational pipeline for three-dimensional fast neural magnetic detection electrical impedance tomography (MDEIT), (2) determine whether constant current or constant voltage is preferable for MDEIT, (3) perform reconstructions of simulated neural activity in a human head model with realistic noise and compare MDEIT to EIT and (4) perform a two-dimensional study in a saline tank for MDEIT with optically pumped magnetometers (OPMs) and compare reconstruction algorithms. Approach. Forward modelling and image reconstruction were performed with a realistic model of a human head in three dimensions and at three noise levels for four perturbations representing neural activity. Images were compared using the error in the position and size of the reconstructed perturbations. Two-dimensional MDEIT was performed in a saline tank with a resistive perturbation and one OPM. Six reconstruction algorithms were compared using the error in the position and size of the reconstructed perturbations. Main results. A computational pipeline was developed in COMSOL Multiphysics, reducing the Jacobian calculation time from months to days. MDEIT reconstructed images with a lower reconstruction error than EIT with a mean difference of 7.0%, 5.5% and 11% for three noise cases representing current noise, reduced current source noise and reduced current source and magnetometer noise. A rank analysis concluded that the MDEIT Jacobian was less rank-deficient than the EIT Jacobian. Reconstructions of a phantom in a saline tank had a best reconstruction error of 13%, achieved using 0th-order Tikhonov regularisation with simulated noise-based correction. Significance. This study demonstrated that three-dimensional MDEIT for neural imaging is feasible and that MDEIT reconstructed superior images to EIT, which can be explained by the lesser rank deficiency of the MDEIT Jacobian. Reconstructions of a perturbation in a saline tank demonstrated a proof of principle for two-dimensional MDEIT with OPMs and identified the best reconstruction algorithm.
Negative frequencies in pulse propagation equations and the double analytic signal
Authors: Aguero-Santacruz Raul , Bermudez David
Published: October 2023

In recent years, the topic of negative frequencies has resurfaced in optics motivated by the optical analogue of Hawking radiation. We discuss the physical meaning of negative frequencies and the conditions under which they are relevant. We review how negative frequencies are treated in current pulse propagation models based on the electric field (EF) and the analytic signal (AS). We focus on experimentally measured signals predicted by the conservation of negative comoving frequency in the nonlinear polarization terms to advance these concepts. We propose a new formalism called the double analytic signal (DAS) which clearly separates negative frequencies from positive ones. Additionally, we reduce this new formalism to the AS to prove their equivalence. Throughout the paper, we present numerical solutions of the unidirectional pulse propagation equation to illustrate the EF, AS, and DAS formalisms and to highlight their differences.
A first principle investigation of electronic, mechanical, optical and transport properties of A2AgAlI6(A = Rb, K, Na) for energy harvesting
Authors: Haq Anwar ul , Ahmad Tasawer Shahzad , Amin Muhammad , Bakar Abu , Afaq A , Ehsan Nimra , Ramay Shahid M , Siddig Abubaker Ahmed
Published: October 2023

The structural, elastic, and optoelectronic properties of cubic double halide perovskites A2AgAlI6 (A = Na, K, Rb) were calculated using the full potential linearized augmented plane wave method. The structural stability of these materials was demonstrated using Goldsmith’s tolerance and modified tolerance. The optoelectronic properties were analyzed using the complex dielectric function and density of states. The potential application of this compound is indicated by the absorption and conduction of light in the visible spectrum. The direct bandgap values of 1.77 eV, 1.74 eV, and 1.64 eV for the compound A2AgAlI6 (A = Rb, K, Na) suggest its usefulness in solar panels. The electrical and thermal conductivities, and Seebeck coefficient of A2AgAlI6 (A = Rb, K, Na) were also determined.
Resilient evaluation algorithm of caesium fountain clock based on robust adaptive observation model
Authors: Wang Xiaobin , Yang Yuanxi , Lin Yuting , Wang Bo , Han Chunhao
Published: October 2023

The caesium fountain clock (CSF) is a primary frequency standard used to define the second, which can greatly improve the autonomous timekeeping ability of laboratories. However, CSF are susceptible to issues such as data interruptions, outliers, and significant fluctuations during operation, ultimately hindering their application in timekeeping. To address these issues, a resilient evaluation algorithm based on a robust adaptive observation model has been proposed. Robust and adaptive factors were introduced into the observation model of the Kalman filter to mitigate abnormal CSF operations. The proposed algorithm was tested through simulations and experiments, which demonstrated significant improvements in the accuracy and stability of the evaluation. As a result, this algorithm effectively reduces the impact of abnormal CSF operations and expands the application scope of CSF in the field of timekeeping.
Bounds on eigenfunctions of quantum cat maps
Authors: Kim Elena , Koirala Robert
Published: October 2023

We study ℓ
∞ norms of ℓ
2-normalized eigenfunctions of quantum cat maps. For maps with short quantum periods (constructed by Bonechi and de Biévre in F Bonechi and S De Bièvre (2000, Communications in Mathematical Physics, 211, 659–686)) we show that there exists a sequence of eigenfunctions u with

∥
u

∥

∞

≳

log
N

−
1

/

2

. For general eigenfunctions we show the upper bound

∥
u

∥

∞

≲

log
N

−
1

/

2

. Here the semiclassical parameter is

h
=

2
π
N

−
1

. Our upper bound is analogous to the one proved by Bérard in P Bérard (1977, Mathematische Zeitschrift, 155, 249-276) for compact Riemannian manifolds without conjugate points.
Accurate ab initio calculations of adiabatic energy and dipole moment: Prospects for the formation of cold Alkaline-Earth-Francium molecular ions ALKE-Fr+ (ALKE = Be, Mg, Ca, and Sr)
Authors: Zrafi Wissem , Hela Ladjimi , Berriche Hamid
Published: October 2023

Alkaline-earth and alkali-metal mixtures have an electronic structure that is perfect for laser cooling. This makes them highly attractive for trapping and laser cooling experiments, allowing the formation of cold molecules. For this object, potential-energy curves and relevant spectroscopic parameters of the low-lying electronic excited states of 1,3Σ+, 1,3Π, and 1,3Δ symmetries of molecular-ion systems composed of alkaline-earth-ion and Francium alkali-metal-atom: ALKE-Fr+ (ALKE = Be, Mg, Ca and Sr), are determined using advanced theoretical technique in quantum chemistry, including a non-empirical pseudopotential, core-valence correlation, large Gaussian basis sets and Full Configuration Interaction (FCI). In order to obtain a more accurate understanding of the electronic structure of these systems, we also determined transition and permanent dipole moments and vibrational properties. Thereafter, the spontaneous and the black-body stimulated transition rates were determined and were employed to calculate lifetimes for all vibrational states of the ground electronic states 11Σ+ of molecular-ions under consideration. For the first and the second excited states, radiative lifetimes were investigated via the Franck–Condon approximation including bound-bound and bound-free transitions. High diagonal structure and large Franck Condon Factor (FCF) values f
00 = 0.987, f
11 = 0.959 and f
22 = 0.919 were obtained for the 11Π (v′ = 0, 1, 2)→ 11Σ+ (v = 0, 1, 2) transition making the BeFr+ system a good candidate for laser cooling. Furthermore, the current results could be used to investigate elastic scattering properties in cold-ion-atom collisions for the first excited states and may help the experimentalists for possible formation, spectroscopy, and photoassociation of cold ion-atom mixtures.
Effects of film thickness on crystal structure, surface topography, optical, and photoelectric properties of Ga2O3 thin film based solar blind photodetectors
Authors: Li Zheng-Nan , Wang Zhao-Cai , Li Chen , Lu Bao-Lin , Yan Wei , Huang Chen-Long , Zhang Tao , Luo Yin-Hong , Zheng Ren-Kui
Published: October 2023

β-Ga2O3 epitaxial thin films with different thicknesses were grown on Al2O3 (0001) substrates by the pulse laser deposition technology. The full width at half maximum of XRD rocking curve, grain size, surface roughness, and optical absorbance (200–300 nm) of the β-Ga2O3 films increase with increasing film thickness. In addition, with increasing film thickness, the adsorption edge presents a red-shift phenomenon, which is accompanied by a slight decrease in the optical band gap (

E

g

). The metal-semiconductor-metal type photodetector made with the 401-nm β-Ga2O3 film shows the maximal photocurrent (1.06 μA @ 10 V), photo-to-dark current ratio (6.96 × 104), responsivity (90 mA W−1), and detectivity (0.5 × 1011 Jones) under 254-nm UV light illumination with a light intensity of 98.4 μW/cm2. Moreover, the 401-nm photodetector displays a small rise time of 0.111/0.561 s and a decay time of 0.046/0.047 s as well as a good stability and repeatability. These findings provide useful reference for the fabrication of β-Ga2O3 film based solar blind ultraviolet photodetectors.
Excellent thermoelectric transport performance in semiconducting hhk-silicene
Authors: Yan Peng , Wu Qihong , Wang Cong , Ding Guangqian , Qin Dan
Published: October 2023

Unlike graphene-like silicene, a recently reported hybrid honeycomb-kagome (hhk) silicene is a semiconductor instead of a gapless Dirac-cone, which has great potential applications in semiconducting devices. Here, using first-principles calculations combined with Boltzmann transport equation, we find that hhk-silicene has high Seebeck coefficient and power factor as arising from the moderate band-gap and low effective mass. Meanwhile, compared to graphene-like silicene, the soften acoustic branches and enhanced anharmonicity lead to the extremely low lattice thermal conductivity, i.e., 0.68 W mK−1 at 300 K. Calculated thermoelectric figure of merit reaches 1.98 at 300 K, which is a recorded value among two-dimensional materials, indicating the potential of hhk-silicene as a thermoelectric material.
Superposition of modulated nonlinear waves in inhomogeneous systems with negative coherent coupling
Authors: Jia Shuoshuo , Jia Heping , Yang Rongcao , Fan Kaikai
Published: October 2023

The superimposed wave solutions of the variable coefficient nonlinear Schrödinger equations with negative coherent coupling are derived under a more relaxed constraint condition than those in previous literatures. For the benefit of the more relaxed constraint, the dispersion, nonlinearity, and gain/loss can be designed freely, and the obtained solutions can describe the nonlinear waves in general inhomogeneous optical fiber systems. The obtained solutions with two free phase parameters can be deemed to be the superposition of the typical simple modulated solutions, and the arbitrary of the optical parameters and the free phase parameters be expected to give the rise of abundant forms of modulation functions, that leads to the diverse characteristics of superimposed waves. Take the kink dispersion fiber systems with constant gain/loss and trigonometric gain/loss as examples, rich dynamics of the superimposed waves are displayed. By changing the gain/loss, the physical features of superimposed waves, such as the amplitudes of solitons and Kuznetsov-Ma breathers, the widths of solitons, the distances between Kuznetsov-Ma breathers, and the backgrounds of Akhmediev breathers and rogue waves can be controlled. The interaction of solitons or Kuznetsov-Ma breathers, and the number of the rogue waves or Akhmediev breathers can also be manipulated by selecting appropriate value of gain/loss. The results presented here may be useful to explore the diverse dynamics of superimposed waves and prove significance for the control of nonlinear waves in weakly birefringent fibers.
Breakdown characteristics of nitrogen at different pressures in alternating non-uniform electric fields
Authors: Wang Yilong , Zheng Yuesheng , Serdyuk Yuriy V
Published: October 2023

AC breakdown characteristics of nitrogen at different pressures in electric fields with different degrees of non-uniformity provided by a sphere-plane electrode system have been investigated. It is found that the measured breakdown voltages obey Paschen’s law at the values of the field factor (the ration of the maximum field strength between electrodes to the average field strength) below ∼2. Deviations start to appear and increase gradually if the field factor increases above this threshold. Respectively, the dependence of the breakdown voltage U
b on the product of pressure p and gap distance d changes from been linear U
b ∼ p ×d to a more complex relationship of type U
b ∼ p ×ln(d). It is found that the maximum field strength corresponding to the breakdown increases with increasing gas pressure and decreasing electrode radius but it is independent on the gap distance. The breakdown voltages predicted by the streamer criterion agree well with the experimental data. The results obtained for nitrogen were compared with the breakdown characteristics of air and it was found that at the values of the field factor below 9, the breakdown strength of nitrogen was higher than that of ambient air.
On slow-flow dynamics, stability charts, and vibration elimination of a self-excited structure utilizing a novel control technique
Authors: Saeed Nasser A , Ashour Amal , Abdelhafez Hassan , Sharaf Mohamed
Published: October 2023

This work focuses on vibration elimination, bifurcation control, and stability achievement in a harmonically forced self-excited nonlinear oscillator. A novel control technique called the Integral Resonant Positive Position Feedback Controller (

IRPPFC

) has been introduced in this study. The proposed controller is composed of second-order and first-order filters, integrated into the targeted oscillator in nonlinear form. Then, the averaging equations governing the slow-flow dynamics of the coupled systems are deduced. Subsequently, the relevant nonlinear algebraic system, which characterizes the static bifurcation, is obtained. The effectiveness of the controller in eliminating system vibrations, controlling nonlinear bifurcations, and stabilizing the unstable motion is investigated through bifurcation diagrams, two-dimensional stability charts, and numerical simulations of the instantaneous vibrations. The conducted analyses approved that the

IRPPFC

not only can stabilize the unstable motion of the considered system, but also it can completely eliminate the self-excited vibration regardless of the forcing magnitude and excitation frequencies. Furthermore, a comparative analysis is conducted to evaluate the control performance of the

IRPPFC

in comparison to previously utilized control techniques for vibration control in self-excited systems. The comparative results demonstrate that the

IRPPFC

exhibits superior performance in terms of vibration elimination efficiency, bifurcation control, and stability achievement. Finally, numerical validation corroborated our analytical findings, showing alignment with the analytical solution. Moreover, the simulation results demonstrated that the

IRPPFC

effectively mitigates undesired vibrations, reducing them to zero in a short transient period.
Effects of different carbides content and brazing process on the electrochemical behaviour of vacuum brazed WC-10Ni+NiCrBSi coatings
Authors: Zhu Jiawei , Liu Zhaolong , Yuan Hongtao , Zhou Hansen , Qiao Yanxin , Xu Xiangping , Zou Jiasheng
Published: October 2023

This study prepared a WC-10Ni/NiCrBSi composite coating on Q235 steel employing flexible coating cloth and vacuum brazing technologies. The surface hardness and corrosion resistance of the coating were characterised by the Vickers hardness, electrochemical, and micro-electrochemical tests. The results show that the corrosion resistance of the coating improved with the increase in cladding temperature. Moreover, with the increase in WC-10Ni content, the corrosion resistance of the coating decreased. Through transmission electron microscopy, scanning electron microscopy, and energy dispersive spectroscopy analysis, it is shown that there is galvanic corrosion in the micro-zone corrosion, where the WC particles are protected as cathodes, and the hardness of the coating is not affected by electrochemical behaviour. Thus, the hardness of the coating is not affected when it is applied in a corrosive environment.
An incommensurate fractional order model for complex dynamics of viral infection with immunity
Authors: Dutta Hemen , Phukan Jyotiska
Published: October 2023

This paper deals with an incommensurate fractional order mathematical model for dynamic analysis of viral infection with immunity. The primary focus of the work is to explore stability analysis of this version of incommensurate fractional order model with harmonic mean type incidence function and fractional derivative in Caputo sense. First, well-posed ness of the model has been established by analyzing existence and uniqueness of the solution. In the next section, stability analysis of the equilibrium points has been caried out based on the basic reproduction number. Sensitivity analysis of the threshold parameter have been performed in the following sections. Finally, rigorous numerical simulations have been performed to support the theoretical findings as well as to observe the effect of various fractional orders and incidence function.
Achieving spatial superresolution with engineered spatial modes
Authors: Thachil Jerin A , Ramanan B , Kumar Ashok
Published: October 2023

Rayleigh’s criterion sets a limit on the minimum separation between two incoherent point sources to be resolved into distinct objects. However, superresolution techniques have been developed to circumvent Rayleigh’s criterion. These techniques mainly deal with single parameter estimation and require prior information about the centroid. Here, we use multi-parameter estimation tools to simultaneously and optimally retrieve information about the centroid and object separation. Collective measurements on photons using two-photon interference followed by spatially resolved detection have significantly improved over direct detection schemes. Following the same approach, we extend the analysis of the two-photon interference protocol to spatially engineered photons having a Pearson type VII profile with arbitrary positive excess kurtosis. We calculate the precision limits in the current measurement scheme as well as the ultimate precision limits based on the quantum Cramer–Rao bound for different spatial modes. We theoretically show that such engineered pulses show enhanced precision with increasing kurtosis in simultaneous estimation of the centroid and object separation compared to a Gaussian amplitude profile. Furthermore, we discuss an experimental setup to realize the proposed superresolution scheme.
Analysis of quantum systems subject to inverse trigonometry Scarf plus Coulomb potential in N-dimensions
Authors: Özfidan Aysel
Published: October 2023

We present approximate solutions of the N-dimensional Klein–Gordon equation in the presence of a superposition of inverse trigonometry Scarf potential and Coulomb potential through asymptotic iteration approach. With the purpose of dealing with the

l

N
−
1

-state, we use Greene-Aldrich approximation which is valid for the small values of the screening parameter. The analytical expressions for the relativistic energy eigenvalues and the corresponding eigenfunctions are established in hyperspherical coordinates. The normalized hyper-radial wavefunction is expressed in terms of hypergeometric and Jacobi polynomials. We analyze the dependences of the relativistic energy levels on the dimensions. We also discuss the effect of the screening parameter on the relativistic energy spectrum. The expectation values of inverse position

r

−
1

,

the square of inverse position

r

−
2

,

kinetic energy

T

and square of momentum

p

2

in N-dimensional space are reported using the Hellmann-Feynmann theorem. Discussing the special cases of the relevant potential, we show the accuracy of our results.
Towards optimal and robust f_nl constraints with multi-tracer analyses
Authors: Barreira Alexandre , Krause Elisabeth
Published: October 2023

We discuss the potential of the multi-tracer technique to improve observational constraints of the local primordial non-Gaussianity (PNG) parameter f

nl
 
from the galaxy power spectrum. For two galaxy samples A and B, the constraining power is ∝ |bB

1
bA
ϕ
- bA

1
bB
ϕ
|, where b
1 and bϕ
are the linear and PNG galaxy bias parameters. We show this allows for significantly improved constraints compared to the traditional expectation ∝ |bA
- bB
| based on naive universality-like relations where bϕ
∝ b
1. Using IllustrisTNG galaxy simulation data, we find that different equal galaxy number splits of the full sample lead to different |bB

1
bA
ϕ
- bA

1
bB
ϕ
|, and thus have different constraining power. Of all of the strategies explored, splitting by g-r color is the most promising, more than doubling the significance of detecting f

nl

 bϕ
≠ 0. Importantly, since these are constraints on f

nl
 
bϕ
and not f

nl
, they do not require priors on the bϕ
(b
1) relation. For direct constraints on f

nl
, we show that multi-tracer constraints can be significantly more robust than single-tracer to bϕ
misspecifications and uncertainties; this relaxes the precision and accuracy requirements for bϕ
priors. Our results present new opportunities to improve our chances to detect and robustly constrain f

nl
, and strongly motivate galaxy formation simulation campaigns to calibrate the bϕ
(b
1) relation.
Higher-order Allan variance for atomic clocks of arbitrary order: mathematical foundation
Authors: Ishizaki Takayuki , Ichimura Taichi , Kawaguchi Takahiro , Yano Yuichiro , Hanado Yuko
Published: October 2023

In this paper, we perform a time-domain analysis of the higher-order Allan variance for atomic clock models of arbitrary order. Adopting a standard atomic clock model where the time series of the clock reading deviation is expressed as a Wiener or integrated Wiener process, we define the higher-order Allan variance as the mean squared higher-order difference of the clock reading deviation. The main results of this paper are threefold. First, we prove that the higher-order difference operation of the clock reading deviation, which can be interpreted as a linear aggregation with binomial coefficients, is not only sufficient but also necessary for a resulting aggregated time series to be an independent and identically distributed Gaussian process. Second, we derive a complete analytical expression of the higher-order Allan variance, which consists of both time-dependent and time-independent terms. Third, we prove that the higher-order Allan variance is time-independent if and only if the order of difference operation is greater than or equal to the order of the atomic clock model.
Integration and dosimetric validation of a dynamic collimation system for pencil beam scanning proton therapy
Authors: Nelson Nicholas P , Culberson Wesley S , Hyer Daniel E , Geoghegan Theodore J , Patwardhan Kaustubh A , Smith Blake R , Flynn Ryan T , Gutiérrez Alonso N , Boland Thibault , Hill Patrick M
Published: October 2023

Objective. To integrate a Dynamic Collimation System (DCS) into a pencil beam scanning (PBS) proton therapy system and validate its dosimetric impact. Approach. Uncollimated and collimated treatment fields were developed for clinically relevant targets using an in-house treatment plan optimizer and an experimentally validated Monte Carlo model of the DCS and IBA dedicated nozzle (DN) system. The dose reduction induced by the DCS was quantified by calculating the mean dose in 10- and 30-mm two-dimensional rinds surrounding the target. A select number of plans were then used to experimentally validate the mechanical integration of the DCS and beam scanning controller system through measurements with the MatriXX-PT ionization chamber array and EBT3 film. Absolute doses were verified at the central axis at various depths using the IBA MatriXX-PT and PPC05 ionization chamber. Main results. Simulations demonstrated a maximum mean dose reduction of 12% for the 10 mm rind region and 45% for the 30 mm rind region when utilizing the DCS. Excellent agreement was observed between Monte Carlo simulations, EBT3 film, and MatriXX-PT measurements, with gamma pass rates exceeding 94.9% for all tested plans at the 3%/2 mm criterion. Absolute central axis doses showed an average verification difference of 1.4% between Monte Carlo and MatriXX-PT/PPC05 measurements. Significance. We have successfully dosimetrically validated the delivery of dynamically collimated proton therapy for clinically relevant delivery patterns and dose distributions with the DCS. Monte Carlo simulations were employed to assess dose reductions and treatment planning considerations associated with the DCS.