bluuebunny/crossref_metadata_2025 huggingface dataset:
Endolysosomal vesicles at the center of B cell activation
Authors: Hämälistö Saara , Del Valle Batalla Felipe , Yuseff María Isabel , Mattila Pieta K.
Published: February 2024

The endolysosomal system specializes in degrading cellular components and is crucial to maintaining homeostasis and adapting rapidly to metabolic and environmental cues. Cells of the immune system exploit this network to process antigens or promote cell death by secreting lysosome-related vesicles. In B lymphocytes, lysosomes are harnessed to facilitate the extraction of antigens and to promote their processing into peptides for presentation to T cells, critical steps to mount protective high-affinity antibody responses. Intriguingly, lysosomal vesicles are now considered important signaling units within cells and also display secretory functions by releasing their content to the extracellular space. In this review, we focus on how B cells use pathways involved in the intracellular trafficking, secretion, and function of endolysosomes to promote adaptive immune responses. A basic understanding of such mechanisms poses an interesting frontier for the development of therapeutic strategies in the context of cancer and autoimmune diseases.
Increasing stability of a linearized inverse boundary value problem for a nonlinear Schrödinger equation on transversally anisotropic manifolds
Authors: Lu Shuai , Zhai Jian
Published: February 2024

We consider the problem of recovering a nonlinear potential function in a nonlinear Schrödinger equation on transversally anisotropic manifolds from the linearized Dirichlet-to-Neumann map at a large wavenumber. By calibrating the complex geometric optics solutions according to the wavenumber, we prove the increasing stability of recovering the coefficient of a cubic term as the wavenumber becomes large.
Performance analysis of carbon nanotube and graphene nanoribbon based biochemical sensors at atomic scale
Authors: Bhat Manasa , Ghosh Kaustab
Published: February 2024

Advancements in fabrication technologies have led to the possibility of synthesizing atomic-scale graphene nanoribbon (GNR) and carbon nanotube (CNT) based nanodevices. The purpose of this study was to model the electronic properties and electrical characteristics of these devices by atomistic modeling using density functional theory and the non-equilibrium Green’s function and compare the effects of molecular functionalization and sensing. The potential profile of the device was computed using the three-dimensional Poisson equation for smaller applied bias within one voltage range. Simulations showed a bandgap of 1 eV for armchair GNRs (AGNRs), which were insensitive to functionalized amine molecules, resulting in fewer alterations in the density of states (DoS), transmission spectra and the device current (ΔI). The bandgap further increased to 2 eV upon rolling the GNR into a armchair CNT (ACNT), which further decreased sensitivity. However, changing the configuration of the AGNR to a zigzag GNR (ZGNR) led to remarkable changes in the DoS and transmission spectra and a significant improvement in sensitivity. This improvement increased by 1.5–2 times upon rolling the ZGNR into a zigzag CNT (ZCNT). Thus, at lower dimensions in atomic scale, we found an alteration in device current of the carbon structures that was directly proportional to sensitivity in the following order: ΔI
ACNT < ΔI
AGNR < ΔI
ZGNR < ΔI
ZCNT. However, the same was found to fall for ZGNR and ZCNT with an increase in width to length (W/L) ratio. This highlights the importance of smaller atomic structures and this work provides a guideline for effective utilization of these structures for biochemical sensing.
Advances in complex oxide quantum materials through new approaches to molecular beam epitaxy
Authors: Rimal Gaurab , Comes Ryan B
Published: February 2024

Molecular beam epitaxy (MBE), a workhorse of the semiconductor industry, has progressed rapidly in the last few decades in the development of novel materials. Recent developments in condensed matter and materials physics have seen the rise of many novel quantum materials that require ultra-clean and high-quality samples for fundamental studies and applications. Novel oxide-based quantum materials synthesized using MBE have advanced the development of the field and materials. In this review, we discuss the recent progress in new MBE techniques that have enabled synthesis of complex oxides that exhibit ‘quantum’ phenomena, including superconductivity and topological electronic states. We show how these techniques have produced breakthroughs in the synthesis of 4d and 5d oxide films and heterostructures that are of particular interest as quantum materials. These new techniques in MBE offer a bright future for the synthesis of ultra-high quality oxide quantum materials.
Artificial neural network for deciphering the structural transformation of condensed ZnO by extended x-ray absorption fine structure spectroscopy
Authors: Liao Jiangwen , Pei Jiajing , Zhang Guikai , An Pengfei , Chu Shengqi , Ji Yuanyuan , Huang Huan , Zhang Jing , Dong Juncai
Published: February 2024

Pressure-induced structural phase transitions play a pivotal role in unlocking novel material functionalities and facilitating innovations in materials science. Nonetheless, unveiling the mechanisms of densification, which relies heavily on precise and comprehensive structural analysis, remains a challenge. Herein, we investigated the archetypal B4 → B1 phase transition pathway in ZnO by combining x-ray absorption fine structure (XAFS) spectroscopy with machine learning. Specifically, we developed an artificial neural network (NN) to decipher the extended-XAFS spectra by reconstructing the partial radial distribution functions of Zn–O/Zn pairs. This provided us with access to the evolution of the structural statistics for all the coordination shells in condensed ZnO, enabling us to accurately track the changes in the internal structural parameter u and the anharmonic effect. We observed a clear decrease in u and an increased anharmonicity near the onset of the B4 → B1 phase transition, indicating a preference for the iT phase as the intermediate state to initiate the phase transition that can arise from the softening of shear phonon modes. This study suggests that NN-based approach can facilitate a more comprehensive and efficient interpretation of XAFS under complex in-situ conditions, which paves the way for highly automated data processing pipelines for high-throughput and real-time characterizations in next-generation synchrotron photon sources.
Utilizing VQ-VAE for end-to-end health indicator generation in predicting rolling bearing RUL
Authors: Wang Junliang , Zhang Qinghua , Zhu Guanhua , Sun Guoxi
Published: February 2024

The prediction of the remaining useful life of rolling bearings is a pivotal issue in industrial production. A crucial approach to tackling this issue involves transforming vibration signals into health indicators (HI) to aid model training. This paper presents an end-to-end HI construction method, vector quantised variational autoencoder (VQ-VAE), which addresses the need for dimensionality reduction of latent variables in traditional unsupervised learning methods such as autoencoder. Moreover, concerning the inadequacy of traditional statistical metrics in reflecting curve fluctuations accurately, two novel statistical metrics, mean absolute distance (MAD) and mean variance (MV), are introduced. These metrics accurately depict the fluctuation patterns in the curves, thereby indicating the model’s accuracy in discerning similar features. On the PMH2012 dataset, methods employing VQ-VAE for label construction achieved lower values for MAD and MV. Furthermore, the ASTCN prediction model trained with VQ-VAE labels demonstrated commendable performance, attaining the lowest values for MAD and MV.
Investigation of combined rock-breaking ability of sawblade and conical pick
Authors: Wang Zhiwen , Zeng Qingliang , Wan Lirong , Lu Zhenguo , Liu Zhihai
Published: February 2024

To solve the problem of severe wear and low rock-breaking efficiency of a conical pick during rock cutting, a method of rock-breaking using a sawblade and conical pick is proposed, which can improve the rock-breaking ability and efficiency. Test benches for the sawblade rock cutting and conical-pick breaking were established to verify the numerical simulation model and improve the numerical simulation accuracy. The numerical simulation model of sawblade and conical-pick rock-cutting was used to investigate the effect of the cutting parameters on cutting performance. Based on the numerical simulation results of rock-breaking, a prediction model of the cutting force and specific cutting energy consumption for combined rock-breaking with a sawblade and conical pick was developed. This provides a comparative analysis basis for the combined rock-breaking capacity of sawblades and conical picks as well as traditional conical-pick rock-breaking. The results indicate that the cutting force, specific cutting energy consumption, and rock-breaking efficiency of combined rock-breaking with a sawblade and conical pick are better than those of the traditional conical pick. The research results provide a theoretical foundation for applying a combined rock-breaking method to sawblades and conical picks in engineering practice.
Rapid and large-scale synthesis of MoS2 via ultraviolet laser-assisted technology for photodetector applications
Authors: Xu Tingwei , Zeng Xiangbin , Hu Shijiao , Wang Wenzhao , Bao Xiaoqing , Peng Yu , Deng Huaicheng , Gan Zhuocheng , Wen Zhiqi , Zhang Wenhao , Chen Lihong
Published: February 2024

Two-dimensional transition metal dichalcogenide (TMDC) thin films have been extensively employed in microelectronics research. Molybdenum disulfide (MoS2), as one of prominent candidates of this class, has been applied in photodetectors, integrated electronic devices, gas sensing, and electrochemical catalysis, owing to its extraordinary optoelectronic, chemical, and mechanical properties. Synthesis of MoS2 crystal film is the key to its application. However, the reported technology revealed several drawbacks, containing limited surface area, prolonged high-temperature environment, and unsatisfying crystallinity. In order to enhance the convenience of MoS2 applications, there is a pressing need for optimized fabrication technology, which could be quicker, with a large area, with adequate crystallinity and heat-saving. In this work, we presented an ultraviolet laser-assisted synthesis technology, accomplishing rapid growth (with the growth rate of about 40 μm s−1) of centimeter-scale MoS2 films at room temperature. To achieve this, we self-assembled a displaceable reaction chamber system, coupled with krypton fluoride ultraviolet pulse laser. The laser motion speed and trajectory could be customized in the software, allowing the maskless patterning of crystal films. As application, we exhibited a photodetector with the integration of synthesized MoS2 and lead sulfide colloidal quantum dots (PbS CQDs), displaying broadband photodetection from ultraviolet, visible to near-infrared spectrum (365–1550 nm), with the detectivity of 109–1010 Jones, and the rising time of 0.2–0.3 s. This work not only demonstrated a high-process-efficiency synthesis of TMDC materials, but also has opened up new opportunities for ultraviolet laser used in optoelectronics.
Differential pressure sensors based on transfer-free piezoresistive layered PdSe2 thin films
Authors: Gong Yimin , Liu Liwen , Zhang Rui , Lin Jie , Yang Zhuojun , Wen Shaofeng , Yin Yi , Lan Changyong , Li Chun
Published: February 2024

Piezoresistive layered two-dimensional (2D) crystals offer intriguing promise as pressure sensors for microelectromechanical systems (MEMS) due to their remarkable strain-induced conductivity modulation. However, integration of the conventional chemical vapor deposition grown 2D thin films onto a micromachined silicon platform requires a complex transfer process, which degrades their strain-sensing performance. In this study, we present a differential pressure sensor built on a transfer-free piezoresistive PdSe2 polycrystalline film deposited on a SiN
x
membrane by plasma-enhanced selenization of a metal film at a temperature as low as 200 °C. Based on the resistance change and finite element strain analysis of the film under membrane deflection, we show that a 7.9 nm thick PdSe2 film has a gauge factor (GF) of −43.3, which is ten times larger than that of polycrystalline silicon. The large GF enables the development of a diaphragm pressure sensor with a high sensitivity of 3.9 × 10−4 kPa−1 within the differential pressure range of 0–60 kPa. In addition, the sensor with a Wheatstone bridge circuit achieves a high voltage sensitivity of 1.04 mV·kPa−1, a rapid response time of less than 97 ms, and small output voltage variation of 8.1 mV in the temperature range of 25 °C to 55 °C. This transfer-free and low-temperature grown PdSe2 piezoresistive thin film is promising for MEMS transducer devices.
The Franz–Keldysh effect in the optical absorption spectrum of a TlGaSe2 layered semiconductor caused by charged native defects
Authors: Gören Serdar , Şale Yasin , Seyidov MirHasan Yu
Published: February 2024

The Franz–Keldysh effect in the optical absorption edge of a bulk TlGaSe2 layered semiconductor poled under an external electric field was investigated in the present work. The Franz–Keldysh shift below the optical bandgap absorption region, as well as the quasi-periodic oscillations above the fundamental bandgap of TlGaSe2, were observed. The measured changes in optical light absorption of the TlGaSe2 sample were revealed after poling processing. The poling technique is used to produce the built-in internal electric field within the TlGaSe2 semiconductor. The frozen-in internal electric field in TlGaSe2 was experimentally monitored through changes in the lineshape of the absorption spectra at the fundamental band edge. The observed results are accurately fitted with the theoretical lineshape function of the Franz–Keldysh absorption tail below the bandgap of TlGaSe2 and quasi-periodic oscillations above the bandgap. A good agreement between the theoretical and experimental results was observed. The present study demonstrated that the Franz–Keldysh effect can be used to identify and characterize the localized internal electric fields originating from electrically active native imperfections in the TlGaSe2 crystals.
Quantum speed limits for change of basis
Authors: Naseri Moein , Macchiavello Chiara , Bruß Dagmar , Horodecki Paweł , Streltsov Alexander
Published: February 2024

Quantum speed limits provide ultimate bounds on the time required to transform one quantum state into another. Here, we introduce a novel notion of quantum speed limits for collections of quantum states, investigating the time for converting a basis of states into an unbiased one as well as basis permutation. Establishing an unbiased basis, we provide tight bounds for the systems of dimension smaller than 5, and general bounds for multi-qubit systems and the Hilbert space dimension d. For two-qubit systems, we show that the fastest transformation implements two Hadamards and a swap of the qubits simultaneously. We further prove that for qutrit systems the evolution time depends on the particular type of the unbiased basis. Permuting a basis, we obtain the exact expression for the Hilbert space of dimension d. We also investigate speed limits for coherence generation, providing the minimal time to establish a certain amount of coherence with a unitary evolution.
Effects of intrinsic point defects (Tii-Vo) on the photocatalytic performance of bilayer rutile/anatase TiO2
Authors: Wang Wenxing , Hou Qingyu
Published: February 2024

Despite the progress on the photocatalytic performance of TiO2 as a typical photocatalytic material, previous research has overlooked the systematic study of the coexistence of Tii and Vo on the photocatalytic property of rutile or anatase TiO2 with bilayers. Studies on the comparative photocatalytic property of these materials have been rarely reported. Thus, the influences of point defects (Tii-Vo) on the photocatalytic performance of bilayer rutile or anatase TiO2 were investigated by GGA + U calculations under density general function theory framework. Results showed that the bilayer rutile Ti24TiiO47 (1 1 0) system exhibited the highest relative stability, strong carrier activity, reduced carrier recombination, and the longest lifetime. Furthermore, the absorption spectrum is clearly red shifted. This system is beneficial for the dissociation of water to produce H2 and O2. This research provides certain theoretical reference value on the design and fabrication of novel bilayer rutile TiO2(1 1 0) surface photocatalysts.
A random boolean network shifted toward a critical point
Authors: Sakiyama Tomoko
Published: February 2024

Random Boolean Networks (RBNs) model complex networks with numerous variables, serving as a tool for gene expression and genetic regulation modeling. RBNs exhibit phase transitions, contingent on node degrees. Given the significance of phase transitions in collective behaviors, the study explores the relationship between RBNs and actual living system networks, which also display critical behaviors. Notably, living systems exhibit such behaviors even beyond the predicted critical point in RBNs. This paper introduces a novel RBNs model incorporating a rewiring process for edge connections/disconnections. In contrast to prior studies, our model includes artificial genes occasionally adding self-loops and creating an instant and temporal lookup table. Consequently, our proposed model demonstrates the edge of chaos at higher node degrees. It serves as an abstract RBNs model generating noisy behaviors from internal agent processes without external parameter tuning.
Rapid cooling method for synthesis of high conducting rhombohedral phase stabilized LiZr2(PO4)3 solid electrolyte
Authors: Rai Krisanta , Kundu Swarup
Published: February 2024

LiZr2(PO4)3 (LZP) solid electrolyte shows excellent stability with Li metal anode and other electrode materials but suffers due to poor ionic conductivity at ambient temperatures. It synthesizes as a low conducting (10−8 S cm−1) triclinic phase at room temperature (RT), which undergoes a phase transition to a high conducting (10−5 S cm−1) rhombohedral phase at around 60 °C. Partial substitution of Zr4+ in LZP with La3+, Sr3+, Al3+, etc. is found to stabilize this high conducting phase at RT. In this work, rhombohedral phase stabilized LZP samples are prepared via the method of rapid cooling, wherein the samples are sintered at high temperatures for relatively short durations of time followed by rapid cooling/quenching to RT. Sample properties are characterized using XRD, SEM, and impedance spectroscopy (IS) techniques. Pristine LZP which was quenched to RT after sintering for 1200 °C/5h exhibited a high RT ionic conductivity value of 0.9 × 10−5 S cm−1. This high ionic conductivity value for pristine LZP has never been reported before. Pristine LZP is mostly found to possess ionic conductivity value in the range of 10−8–10−7 S cm−1 at RT.
Relative variation between γ coordinate and the potential of the Bohr Hamiltonian producing X(4) from Z(4)
Authors: Ajulo K R , Oyewumi K J , Orosun M M , Targema T V
Published: February 2024

In this paper, four degree of freedom γ-rigid solutions of the Bohr Hamiltonian at γ
0 = π/6 are obtained. The relative variation between γ and the potential of the Hamiltonian is employed to retrieve X(4) from Z(4). γ is varied in the interval 0 ≤ γ
0 ≤ π/6 while the potential minimum, β
0, is varied in the interval 0 ≤ β
0 ≤ ∞ . Very small value of β
0 yields Z(4) while a large value of β
0 produces X(4) and SU(3) is realized at β
0 ≈ ∞ . The solutions at γ
0 = 0 correspond to X(4) while the solutions at γ
0 = π/6 yield Z(4): a dynamic link between Z(4) and X(4) critical point symmetries (CPSs) has been provided. The fact that γ and β
0 of the potential play the same role in the dynamical link between Z(4) and X(4) shows that β
0 also measures the departure from axial symmetry to other shapes as γ does. In the experimental realization of the model, the conformation of 192Pt and 194Pt isotopes to the present Z(4) model shows that the present model can be employed in the description of triaxial rotors and γ-soft isotopes. 194Pt is shown to be the best choice for triaxial rigid rotor candidacy. 130Xe, a critical point isotope, which belongs to the class of γ-soft nuclei, reproduces this present model very well in all the states. Consequently, this present model can serve as a critical point model. 40,0 − β
0 distribution for Z(4) and X(4) candidate isotopes shows a significant interval between the two models where the T(4) CPS lies.
Black hole formation in gravitational collapse and their astrophysical implications
Authors: Jaiswal Annu , Kumar Rajesh , Kumar Srivastava Sudhir , Govender Megandhren , Kumar Jas Pacif Shibesh
Published: February 2024

In this study, we have explored the process of black hole (BH) formation occurring in the collapse of a self-gravitating configuration using an innovative approach. The exact solution of the Einstein field equations is obtained in a model-independent way by considering a parametrization of the expansion scalar (Θ) in the background of spherically symmetric space-time geometry governed by the FLRW metric. Smooth matching of the interior solution with the Schwarzschild exterior metric across the boundary hypersurface of the star, together with the condition that the mass function m(t, r) is equal to Schwarzschild mass M, is used to obtain all the physical and geometrical parameters in terms of the stellar mass. The four known massive stars namely R136a3, Melnick, R136c, and R136b with their known astrophysical data (mass, radius, and present age) are used to study the physics of the model both numerically and graphically. We demonstrate that the formation of the apparent horizon occurs earlier than the singular state that is, the collapse of massive stars in our model results in the eventual formation of black holes as their final state. We have conducted an analysis indicating that the lifespans of massive stars are closely related to their respective masses. Our findings demonstrate that more massive stars exhibit considerably shorter lifespans in comparison to their lighter counterparts. Thus, the presented model corresponds to the evolutionary stages of astrophysical stellar objects and theoretically predicts their possible lifespan. We have also shown that our model satisfies the energy conditions and stability requirements via Herrera’s cracking method.
A natural protein-related biopolymer film and its positive role in pearl brightening
Authors: Yan Xuejun , Hu Xianchao , Zhang Xu , Lv Hanzhi , Chen Tao , Yu Siyi , Yan Jun
Published: February 2024

To date, the external micromorphological differences among high-luster pearls and the precise relationship between the organic matrix covered on the external surface of pearl and its luster remain, to a large extent, unknown. Here, using scanning electron microscopy combined with energy-dispersive x-ray spectroscopy, infrared spectroscopy, and Raman spectroscopy, we comparatively investigated the multiscale surface characteristics of representative seawater-cultured pearls with different luster grades. The results showed that a natural protein-related biopolymer film of nano-thickness existed on the surface of high-luster pearls. Moreover, the biopolymer film and the microscale tablets self-assembled by aragonite nanoparticles, which serve as a nanoscale organic film and a microscale plane mirror, respectively, together play key roles in producing the excellent luster. In addition, the higher the content of organic matter covering the external surface of pearls, or the thicker the average thickness of the film, the smoother the surface and the better the luster of pearls. The findings substantially enhance our knowledge of the gemological and morphological characteristics of pearls and their corresponding natural brightening mechanism. Most importantly, this study not only provides some key guidelines on the daily maintenance of pearls and the optimization process for pearl brightening but also inspires optical functional material syntheses.
An angular stable ultra-broadband asymmetric transmission chiral metasurface with efficient linear-polarization conversion
Authors: Ahmed Afzal , Cao Qunsheng , Khan Muhammad Ismail , Shah Gulab , Ahmed Fahad , Khan Muhammad Irshad , Abidin Zain Ul
Published: February 2024

In this paper, a chiral metasurface is presented to effectively attain an ultra-broadband operation of asymmetric transmission with highly efficient cross-polarization conversion. The efficiency of the asymmetric transmission operation in the frequency band ranging from 6.5 to 13 GHz is above 70%. Additionally, in the frequency range from 3.7 to 14 GHz, the cross-polarization conversion realizes greater than 90% polarization conversion ratio. Asymmetric transmission as well as cross-polarization conversion show angular stability against the incident angle of electromagnetic waves up to 45°. To validate the simulation results, the fabricated chiral metasurface is tested and compared with simulation results. The concepts of asymmetric transmission and linear-polarization conversion are demonstrated and physically explained through the distributions of surface currents over metallic layers. This anticipated work has significant applications in telecommunications and radar, as well as potential use in equipment designed for the manipulation of electromagnetic waves.
A regularized (XP)2 model
Authors: Chen Yu-Qi , Ge Zhao-Feng
Published: February 2024

We investigate a dynamic model described by the classical Hamiltonian H(x, p) = (x
2 + a
2)(p
2 + a
2), where a
2 > 0, in classical, semi-classical, and quantum mechanics, respectively. In the high-energy E limit, the phase path resembles that of the

XP

2

model. However, the non-zero value of a acts as a regulator, removing the singularities that appear in the region where x, p ∼ 0, resulting in a discrete spectrum characterized by a logarithmic increase in state density. Classical solutions are described by elliptic functions, with the period being determined by elliptic integrals. In semi-classical approximation, we speculate that the asymptotic Riemann-Siegel formula may be interpreted as summing over contributions from multiply phase paths. We present three different forms of quantized Hamiltonians, and reformulate them into the standard Schrödinger equation with

cosh
2
x

-like potentials. Numerical evaluations of the spectra for these forms are carried out and reveal minor differences in energy levels. Among them, one interesting form possesses Hamiltonian in the Schrödinger equation that is identical to its classical version. In such scenarios, the eigenvalue equations can be expressed as the vanishing of the Mathieu functions’ value at i ∞ points, and furthermore, the Mathieu functions can be represented as the wave functions.
Constructing new high-order polynomial chaotic maps and application in pseudorandom number generator
Authors: Wu Wanqing , Zhou Jipeng
Published: February 2024

The chaotic map have been widely applied in fields such as pseudorandom number generation(PRNG) and image encryption due to its excellent chaotic performance. In this paper, two classes of high-order polynomial chaotic maps of special form are proposed based on the Li-Yorke theorem. The dynamic behavior of the proposed maps is numerically analyzed, including bifurcation and Lyapunov exponent, and the analysis results prove the validity of the proposed conclusions. The proposed polynomial chaotic maps have a larger parameters and chaotic range, as well as a more stable Lyapunov exponent. Furthermore, based on the coupling chaotic systems, we design a pseudorandom number generator(PRNG), and the number of chaos parameters are expanded through the coupling control parameters in a PRNG. Then the performance of the pseudorandom sequence generated by the PRNG is tested and analysed. The test and analysis results show that the pseudorandom sequence has favorabble security, structural complexity, and randomness. Especially, the information entropy of 7.9998 and the key space size of 2208 exceed the recently reported pseudorandom number generators(PRNGs). In comparison with other PRNGs based on chaotic maps in the recent literature, this paper provides comprehensive performance test and analysis of the proposed PRNG and demonstrates its potential for cryptographic applications.
Abrupt focus and bright spot formation in fractional system with PT-symmetric nonlocal nonlinearity
Authors: Bai Xiaoqin , Yang Rongcao , Chen Jing , Bai Juan , Jia Heping
Published: February 2024

We study the dynamics of Gaussian beams in fractional system with PT-symmetric nonlocal nonlinearity. It is found that the Gaussian beam with transverse displacement can abruptly focus to form bright spot in one sub-branch after experiencing a symmetric split, depending on the nonlinear intensity, initial launched amplitude, angle and chirp of the beam, and the initial chirp can shift the time of abrupt focus and bright spot formation. Furthermore, the Talbot-like effect and breather train are explored by setting the initial amplitude parameter of every component of an initial Gaussian beam train. Moreover, for longitudinally periodically modulated nonlinearity, the bright spots can be formed periodically and asymmetrically in two sub-branches for a single Gaussian beam, and Moiré-like lattices can be generated for a Gaussian beam train. Finally, the conical diffraction and crescent-like evolution in the two-dimensional system are investigated in detail. It is found that the direction of crescent-like evolution is determined by the initial launched angles, which may be an inspiration to design channel path through choosing suitable initial launched angles at will.
Modulation of the microstructure, optical properties and electrical properties of zinc-doped nickel oxide films via direct current sputtering power
Authors: Gao Xiaoyong , Meng Xue , Song Tingting , Chen Xu
Published: February 2024

Zinc-doped NiO (NiO:Zn) films were direct-current-magnetron sputtered on the glass substrates. The modulation of the properties of the films via sputtering powers (Pspu) was especially studied. The conducting transition from p to n type was also proposed in mechanism. The NiO:Zn films are all preferentially 〈111〉 oriented. The films with high Pspu almost have small lattice distortion due to the improved crystallization caused by the thermal effect and the Zn element doping. The films begin to exhibit the n-type conduction at 90 W Pspu. The conducting transition from p to n type is mainly attributed to the occupation of Ni vacancies by Zn2+ and the interstitial Zn, and the improved n-type conduction in Pspu range of 140 W through 160 W to the increase in content of the interstitial Zn atoms. The absorption edge of the NiO:Zn films remaining at about 3.7 eV is slightly affected by the increase in Pspu, showing that the doping of the Zn element in the NiO is not mainly in the form of the Ni vacancies occupying ions.
On the importance of heavy fields in pseudo-scalar inflation
Authors: Chen Chong-Bin , Wang Ziwei , Zhou Siyi
Published: February 2024

Pseudo-scalar inflation coupled with U(1) gauge fields through the Chern-Simons term has
been extensively studied. However, new physics arising from UV theories may still influence the
pseudo-scalar field at low-energy scales, potentially impacting predictions of inflation. In the
realm of effective field theory (EFT), we investigated axion inflation, where operators from heavy
fields are also present, in addition to the axion and gauge fields. The integrated out fields
have two significant effects: the non-linear dispersion regime and coupling heavy modes to the
Chern-Simons term. The first effect changes the propagation of the curvature fluctuation, while
the second one results in additional operators that contribute to curvature fluctuation via
inverse decay. We derived the power spectrum and magnitude of equilateral non-Gaussianity in this
low-energy EFT. We found that the second effect could become significant as the mass of heavy
fields approaches Hubble scale.
Prospects for realtime characterization of core-collapse supernova and neutrino properties
Authors: Bendahman Meriem , Goos Isabel , Coelho Joao A.B. , Bugli Matteo , Coleiro Alexis , El Hedri Sonia , Foglizzo Thierry , Franco Davide , Guilet Jérôme , Kouchner Antoine , Raynaud Raphaël , Tayalati Yahya
Published: February 2024

Core-collapse supernovae (CCSNe) offer extremely valuable insights into the dynamics of galaxies. Neutrino time profiles from CCSNe, in particular, could reveal unique details about collapsing stars and particle behavior in dense environments. However, CCSNe in our galaxy and the Large Magellanic Cloud are rare and only one supernova neutrino observation has been made so far. To maximize the information obtained from the next Galactic CCSN, it is essential to combine analyses from multiple neutrino experiments in real time and transmit any relevant information to electromagnetic facilities within minutes. Locating the CCSN, in particular, is challenging, requiring disentangling CCSN localization information from observational features associated with the properties of the supernova progenitor and the physics of the neutrinos. Yet, being able to estimate the progenitor distance from the neutrino signal would be of great help for the optimisation of the electromagnetic follow-up campaign that will start soon after the propagation of the neutrino alert. Existing CCSN distance measurement algorithms based on neutrino observations hence rely on the assumption that neutrino properties can be described by the Standard Model. This paper presents a swift and robust approach to extract CCSN and neutrino physics information, leveraging diverse next-generation neutrino detectors to counteract potential measurement biases from Beyond the Standard Model effects.
JWST’s PEARLS: Improved Flux Calibration for NIRCam
Authors: Ma Zhiyuan , Yan Haojing , Sun Bangzheng , Cohen Seth H. , Jansen Rolf A. , Summers Jake , Windhorst Rogier A. , D’Silva Jordan C. J. , Koekemoer Anton M. , Coe Dan , Conselice Christopher J. , Driver Simon P. , Frye Brenda , Grogin Norman A. , Marshall Madeline A. , Nonino Mario , Ortiz Rafael , Pirzkal Nor , Robotham Aaron , Ryan Russell E. , Willmer Christopher N. A. , Hammel Heidi B. , Milam Stefanie N. , Adams Nathan J. , Cheng Cheng , Hathi Nimish P.
Published: February 2024

The Prime Extragalactic Areas for Reionization and Lensing Science, a James Webb Space Telescope (JWST) GTO program, obtained a set of unique NIRCam observations that have enabled us to significantly improve the default photometric calibration across both NIRCam modules. The observations consisted of three epochs of 4-band (F150W, F200W, F356W, and F444W) NIRCam imaging in the Spitzer IRAC Dark Field (IDF). The three epochs were six months apart and spanned the full duration of Cycle 1. As the IDF is in the JWST continuous viewing zone, we were able to design the observations such that the two modules of NIRCam, modules A and B, were flipped by 180° and completely overlapped each other’s footprints in alternate epochs. We were therefore able to directly compare the photometry of the same objects observed with different modules and detectors, and we found significant photometric residuals up to ∼0.05 mag in some detectors and filters, for the default version of the calibration files that we used (jwst_1039.pmap). Moreover, there are multiplicative gradients present in the data obtained in the two long-wavelength bands. The problem is less severe in the data reduced using the latest pmap (jwst_1130.pmap as of 2023 September), but it is still present, and is non-negligible. We provide a recipe to correct for this systematic effect to bring the two modules onto a more consistent calibration, to a photometric precision better than ∼0.02 mag.
Anomalous time-reversal symmetric non-Hermitian systems
Authors: Yi 易 Yifei 益妃
Published: February 2024

The conditions for the emergence of the non-Hermitian skin effect, as a unique physical response of non-Hermitian systems, have now become one of the hot research topics. In this paper, we study the novel physical responses of non-Hermitian systems with anomalous time-reversal symmetry, in both one dimension and two dimensions. Specifically, we focus on whether the systems will exhibit a non-Hermitian skin effect. We employ the theory of generalized Brillouin zone and also numerical methods to show that the anomalous time-reversal symmetry can prevent the skin effect in one-dimensional non-Hermitian systems, but is unable to exert the same effectiveness in two-dimensional cases.
A new quantum key distribution resource allocation and routing optimization scheme
Authors: Bi 毕 Lin 琳 , Yuan 袁 Xiaotong 晓同 , Wu 吴 Weijie 炜杰 , Lin 林 Shengxi 升熙
Published: February 2024

Quantum key distribution (QKD) is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols. However, due to the stringent requirements of the quantum key generation environment, the generated quantum keys are considered valuable, and the slow key generation rate conflicts with the high-speed data transmission in traditional optical networks. In this paper, for the QKD network with a trusted relay, which is mainly based on point-to-point quantum keys and has complex changes in network resources, we aim to allocate resources reasonably for data packet distribution. Firstly, we formulate a linear programming constraint model for the key resource allocation (KRA) problem based on the time-slot scheduling. Secondly, we propose a new scheduling scheme based on the graded key security requirements (GKSR) and a new micro-log key storage algorithm for effective storage and management of key resources. Finally, we propose a key resource consumption (KRC) routing optimization algorithm to properly allocate time slots, routes, and key resources. Simulation results show that the proposed scheme significantly improves the key distribution success rate and key resource utilization rate, among others.
A Quick Calculation Method for Radiation Pattern of Submillimeter Telescope with Deformation and Displacement
Authors: You Jia , Yao Yi-Wei , Wang Zheng
Published: February 2024

Radiation pattern captures the electromagnetic performance of reflector antennas, which is significantly affected by the deformation of the primary reflector due to gravity and the displacement of the secondary reflector. During the design process of large reflector antennas, a substantial amount of time is often dedicated to iteratively adjusting structural parameters and validating electromagnetic performance. To improve the efficiency of the design process, we first propose an approximate calculation method of optical path difference (OPD) for the deformation of the primary reflector under gravity and the displacement of the secondary reflector. Then an OPD fitting function based on the modified Zernike polynomials is proposed to capture the phase difference of radiation over the aperture plane, based on which the radiation pattern will be obtained quickly by the aperture field integration method. Numerical experiments demonstrate the effectiveness of the proposed quick calculation method for analyzing the radiation pattern of a 10.4 m submillimeter telescope antenna at its highest operating frequency of 856 GHz. In comparison with the numerical simulation method based on GRASP (which is an antenna electromagnetic analysis tool combining physical optics (PO) and physical theory of diffraction (PTD)), the quick calculation method reduces the time for radiation pattern analysis from more than one hour to less than two minutes. Furthermore, the quick calculation method exhibits excellent accuracy for the figure of merit (FOM) of the radiation pattern. Therefore, the proposed quick calculation method can obtain the radiation pattern with high speed and accuracy. Compared to the time-consuming numerical simulation method (PO and PTD), it can be employed for quick analysis of the radiation pattern for the lateral displacement of the secondary reflector and the deformation of the primary reflector under gravity in the design process of a reflector antenna.
Design of the CMS High Granularity Calorimeter trigger primitive generator system
Authors: Ehle I. ,   the CMS collaboration
Published: February 2024

The High Luminosity phase of the LHC (HL-LHC) is planned to begin data taking in 2029, with the instantaneous luminosity expected to increase to 4 times its current value and the average number of particle interactions per bunch crossing increasing by approximately 3.5 times its current value. The current endcap calorimeters in the CMS detector will be replaced by a novel high granularity calorimeter (HGCAL) that will have fine segmentation in both the transverse and longitudinal directions and will be the first such calorimeter specifically optimised for particle flow reconstruction to operate at a colliding-beam experiment. The Level 1 trigger of the CMS experiment will combine the calorimeter data with tracking information to allow particle-flow techniques to be used. The high granularity of the calorimeter leads to about six million readout channels in total, concentrated in one million trigger cells, sampled for the L1 trigger at a rate of 40 MHz. The trigger data volumes will be an order of magnitude above those currently handled in CMS, posing significant challenges for data manipulation and processing. In addition, the trigger algorithms must be able to efficiently reject the huge background rate in the forward region of the detector due to the high pileup environment. The status of the HGCAL trigger architecture and design, as well as the algorithms developed in order to tackled these major issues, is presented here. The data flow is described from the formation and preselection of trigger cells on detector to the generation of two types of trigger primitives off detector, projective towers of energy in the (η, ϕ) plane and three-dimensional clusters of particles. Particle flow will use these 3D clusters, and their formation is described and followed by recent developments in the optimization of their transverse size.
Sparse-view image reconstruction with total-variation minimization applied to sparsely sampled projection data from SiPM-based photon-counting CT
Authors: Sato D. , Arimoto M. , Kotoku J. , Kawashima H. , Kobayashi S. , Okumura K. , Murakami K. , Lucyana F. , Tomoda T. , Kataoka J. , Sagisaka M. , Terazawa S. , Shiota S.
Published: February 2024

We constructed a sparse-view computed tomography (CT) system that combines a compressed
sensing (CS)-based image-reconstruction algorithm and SiPM-based photon-counting (PC) CT. CS-based
image-reconstruction algorithms have been extensively studied for X-ray CT image reconstruction
using fewer projections because they are expected to reduce CT imaging time and radiation exposure
while maintaining CT image quality. In most previous studies, CS-based image-reconstruction
algorithms have been applied to data obtained through numerical simulations or conventional
dual-energy CT. However, studies on PC-CT have been scarce. Therefore, we applied a CS-based
image-reconstruction algorithm to the projection data obtained using our previously established
SiPM-based PC-CT system and evaluated its image quality. We prepared static phantoms equivalent to
iodine-containing contrast agents and a mouse model injected with iodine-containing contrast
agents as subjects. Thereafter, CT scanning was performed. The obtained projection data were
downsampled to simulate a sparse-view situation, and a CS-based image-reconstruction algorithm
with total-variation minimization was applied. Consequently, sparse-view CT images were
successfully reconstructed, and the image quality was maintained even after downsampling the
projection data (downsampling ratios of 1/10 and 1/2 for the rod phantom and mouse model,
respectively). Thus, the imaging time and exposure dose could be remarkably reduced (by a factor
of 10 or 2), indicating that the CS-based image-reconstruction algorithm is effective for PC-CT.
Development of a Triple-GEM detector with strip readout and GEMINI chip for X rays and neutron imaging
Authors: Caruggi F. , Celora A. , Cancelli S. , Gorini G. , Grosso G. , Guiotto F. , Muraro A. , Perelli Cippo E. , Petruzzo M. , Putignano O. , Tardocchi M. , Giarratana L.S. , Croci G.
Published: February 2024

Thermal neutron imaging can be a useful tool in the study of the internal structure of an object. The different attenuation properties of the materials with respect to X rays give rise to different interactions and the result is a complementary non-destructive analysis, which can provide important additional information. This technique has been successfully employed in different areas of work, especially in material science and cultural heritage studies. This paper describes the development of a new detection system and its characterization performed with X ray emissions. The system features the use of a gaseous detector, based on the Gas Electron Multiplier technology, and a fully digital electronic readout, with a combination of custom-made ASICs (called GEMINI) and FPGA boards, enabling fast single photon counting. The detector can be thus used directly for X ray imaging, while the addition of a suitable converter in its active volume will allow for detection of neutrons and for reconstruction of their tracks. The readout system is based on a x-y strip structure and features the reconstruction of single events through the center of mass methodology, allowing for accurate tomography, with sub-mm spatial resolution, in combination with sub-ms time resolution and high rate capabilities (up to MHz/mm2).
On the role of interconnected mini-grids in net-zero emissions electricity system: insights from Nigeria
Authors: Nana Joel Yongoua , Dioha Michael O
Published: February 2024

As developing countries like Nigeria strive to reduce carbon emissions while expanding energy access, mini-grids’ role has gained recognition. However, limited analysis exists regarding the role of interconnected mini-grids (IMGs) in the transition to net-zero emissions electricity generation systems. Here, we employ a bottom-up energy system optimization modeling framework to explore the techno-economic implications of deploying IMGs in net-zero emissions electricity systems, using Nigeria as a case study. We find that IMGs can contribute to modest system-level cost reductions in net-zero emissions electricity systems. IMGs can help minimize stranded electricity generation assets and decrease the reliance on negative emissions technologies in scenarios aiming for net-zero emissions electricity systems by 2050. In scenarios where the net-zero target is delayed until 2070, the widespread deployment of comparatively affordable cleaner generators and the phaseout of fossil fuel power plants may render negative emission technologies unnecessary. The model results further indicate that IMGs can help reduce the use of captive diesel/gasoline gen-sets quickly, and nuclear power has a role in the electricity generation mix in all net-zero emissions scenarios. Moreover, in order to achieve the median per capita electricity consumption observed in high-income countries by the year 2050, Nigeria must undertake a formidable expansion of its current electricity generation capacity at a rate approximately six times greater than that dictated by a business-as-usual trajectory. The study also provides recommendations to address the policy, regulatory, and financial considerations crucial for implementing IMGs successfully.