bluuebunny/crossref_metadata_2025_split huggingface dataset:
A multi-frequency magnetic particle spectroscopy system for systematic characterization and highly sensitive detection of magnetic nanoparticles
Authors: Sun Shaoqi , Sun Shijie , Xu Lijun , Zhong Jing 
Published: April 2024

Abstract
Systematic characterization and highly sensitive detection of magnetic nanoparticles (MNPs) is of great importance to investigate the magnetic properties of the MNPs for biomedical applications. In this study, a multi-frequency magnetic particle spectroscopy (MPS) system is developed to measure the magnetic response of the MNPs in different ac magnetic fields. A model for the description of the output signal of the MPS system is deduced to analyze the signal-to-noise ratio of the MNP harmonics. The noise source, including the Gaussian noise and harmonic distortion from the excitation magnetic field, is quantitatively measured and comprehensively analyzed to investigate their influences on the limit-of-detection (LOD) of the MPS system. The MPS signal and dynamic magnetization curve of the MNPs are measured in different ac magnetic fields with the developed MPS system. In addition, a series of MNP samples with different iron concentrations are prepared for experiments to determine the LOD, indicating an LOD of 2.3 ng in terms of iron. The dependence of the LOD on the Gaussian noise and the harmonic distortion is discussed. The present work indicates that one needs to comprehensively consider the influence factors of the Gaussian noise and harmonic distortion to develop a sensitive MPS system with multi-frequency excitation.
Detection and metrology of micro-nano particles through the integration of image and laser modes
Authors: Tao Yikun , He Hu 
Published: April 2024

Abstract
Micro-nano particles are an indispensable component in various industrial and scientific applications. Accurate granular information is critical for manufacturing products involving these particles. This study presents a novel detection method that merges image and laser modes to achieve precise size and shape determination of micro-nano particles. The proposed method integrates adaptive image analysis with laser particle size fitting to ensure accurate feature detection. Experimental results using ternary precursor samples demonstrate that the fusion mode outperforms both the laser and image modes in terms of size and shape accuracy. The errors of D10, D50, and D90 of the fusion mode are 4.89%, 1.88%, and 2.94%, respectively, which are significantly lower than those obtained using the laser or image mode alone. Additionally, the fusion mode retains the particle shape information from the image mode. The fusion model offers a promising approach for dual-mode detection of micro-nano particles, demonstrating enhanced robustness compared to single-mode methods. Furthermore, the study introduces an image processing method based on a BP neural network classification model that accurately classifies and detects agglomerated and non-agglomerated particles. The classification accuracy reaches 94.98%, and the particle size information remains within the acceptable range.
Fully automated operational modal identification based on scale-space peak picking algorithm and power spectral density estimation
Authors: Li Xiao , Dong Yu-Xia , Zhang Feng-Liang 
Published: April 2024

Abstract
Modal analysis is a fundamental and essential research direction in the field of structural engineering. The ultimate goal is to determine the modal parameters of the structures. However, the existing modal analysis algorithms often require a large number of parameter adjustments and manual intervention during operation, which cannot be fully automated. In order to realize the automatic identification of modal parameters, the automatic operational modal identification method (AOMI) is proposed based on the interpolated power spectral density estimation (IPSE). To achieve more precise spectrum analysis in the low-frequency band, IPSE is employed to perform Fourier transform on the original frequency domain segment with optimized frequency resolution. This enhances the sharpness of the obtained spectrum in the low-frequency range, making peak frequencies more discernible. Subsequently, the scale-space peak picking algorithm is used to automatically obtain the peak of the power spectral density (PSD), thus enabling the automatic identification of the natural frequency. Finally, the frequency domain decomposition method (FDD) is used to identify modal parameters based on the natural frequencies. The effectiveness of AOMI is verified through the modal identification of the old steel truss bridge and the three layer framework. Under the environmental excitation, the frequencies identified by the IPSE method is close to that of FDD, Bayesian fast fourier transform (FFT) and covariance driven stochastic subspace identification (SSI-COV). Furthermore, the PSD obtained through IPSE has sharper peak than that of FDD and the Welch’s method. The damping ratio identification accuracy and modal assurance criterion (MAC) are satisfactory in AOMI, which can improve the automatic performance.
Functionalized MBenes as promising anode materials for high-performance alkali-ion batteries: a first-principles study
Authors: Ahmad Sheraz , Xu Hu , Chen Letian , Din H U , Zhou Zhen 
Published: April 2024

Abstract
The discovery of novel electrode materials based on two-dimensional (2D) structures is critical for alkali metal-ion batteries. Herein, we performed first-principles computations to investigate functionalized MXenes, Mo2BT2 (T = O, S), which are also regarded as B-based MXenes, or named as MBenes, as potential anode materials for Li-ion batteries and beyond. The pristine and T-terminated Mo2BT2 (T = O, S) monolayers reveal metallic character with higher electronic conductivity and are thermodynamically stable with an intrinsic dipole moment. Both Mo2BO2 and Mo2BS2 monolayers exhibit high theoretical Li/Na/K storage capacity and low ion diffusion barriers. These findings suggest that functionalized Mo2BT2 (T = O, S) monolayers are promising for designing viable anode materials for high-performance alkali-ion batteries.
Effects of gamma-ray irradiation on material and electrical properties of AlN gate dielectric on 4H-SiC
Authors: Zhu Xiaogang , Shen Zhanwei , Wang Z J , Liu Zhengran , Miao Yuyang , Yue Shizhong , Fu Zhao , Li Zihao , Zhang Yuning , Hong Rongdun , Wu Shaoxiong , Chen Xiaping , Cai Jiafa , Fu Deyi , Zhang Feng 
Published: April 2024

Abstract
This article investigates the radiation effects on as-deposited and annealed AlN films on 4H-SiC substrates under gamma-rays. The AlN films are prepared using plasma-enhanced-atomic-layer-deposition on an n-type 4H-SiC substrate. The AlN/4H-SiC MIS structure is subjected to gamma-ray irradiation with total doses of 0, 300, and 600 krad(Si). Physical, chemical, and electrical methods were employed to study the variations in surface morphology, charge transport, and interfacial trapping characteristics induced by irradiation. After 300 krad(Si) irradiation, the as-deposited and annealed samples exhibit their highest root mean square values of 0.917 nm and 1.190 nm, respectively, which is attributed to N vacancy defects induced by irradiation. Under irradiation, the flatband voltage (V
fb) of the as-deposited sample shifts from 2.24 to 0.78 V, while the annealed sample shifts from 1.18 to 2.16 V. X-ray photoelectron spectrum analysis reveals the decomposition of O-related defects in the as-deposited AlN and the formation of Al(NO
x
)
y
compounds in the annealed sample. Furthermore, the space-charge-limits-conduction (SCLC) in the as-deposited sample is enhanced after radiation, while the barrier height of the annealed sample decreases from 1.12 to 0.84 eV, accompanied by the occurrence of the SCLC. The physical mechanism of the degradation of electrical performance in irradiated devices is the introduction of defects like N vacancies and O-related defects like Al(NO
x
)
y
. These findings provide valuable insights for SiC power devices in space applications.
Real-time imaging reveal anisotropic dissolution behaviors of silver nanorods
Authors: Dong Meng , Pan Yuchen , Zhu Jingfang , Jia Haiyang , Dong Hui , Xu Feng 
Published: April 2024

Abstract
The morphology and size control of anisotropic nanocrystals are critical for tuning shape-dependent physicochemical properties. Although the anisotropic dissolution process is considered to be an effective means to precisely control the size and morphology of nanocrystals, the anisotropic dissolution mechanism remains poorly understood. Here, using in situ liquid cell transmission electron microscopy, we investigate the anisotropic etching dissolution behaviors of polyvinylpyrrolidone (PVP)-stabilized Ag nanorods in NaCl solution. Results show that etching dissolution occurs only in the longitudinal direction of the nanorod at low chloride concentration (0.2 mM), whereas at high chloride concentration (1 M), the lateral and longitudinal directions of the nanorods are dissolved. First-principles calculations demonstrate that PVP is selectively adsorbed on the {100} crystal plane of silver nanorods, making the tips of nanorods the only reaction sites in the anisotropic etching process. When the chemical potential difference of the Cl− concentration is higher than the diffusion barrier (0.196 eV) of Cl− in the PVP molecule, Cl− penetrates the PVP molecular layer of {100} facets on the side of the Ag nanorods. These findings provide an in-depth insight into the anisotropic etching mechanisms and lay foundations for the controlled preparation and rational design of nanostructures.
Atomic line spectra and the conservation laws
Authors: Goh Ker Liang 
Published: April 2024

Abstract
By conservation of linear momentum an atom recoils after it de-excites by giving out a photon. The de-excitation energy is shared by the photon and the recoiling atom. There was no mention in textbooks of this recoil energy when discussing atomic line spectra. We illustrate why it is valid to assume that the de-excitation energy is the energy of the emitted photon in line spectra around the visible light region.
Time-resolved investigations of a glow mode impulse dielectric barrier discharge in pure ammonia gas by means of E-FISH diagnostic
Authors: Jean-Marie-Desiree R , Najah A , Noël C , De Poucques L , Cuynet S 
Published: April 2024

Abstract
Time-resolved electric field strength measurements have been performed, using an electric-field induced second harmonic (E-FISH) diagnostic, in a nanosecond glow discharge of an impulse dielectric barrier discharge, in an ammonia gas environment. A temporal resolution of 2 ns and a spatial resolution estimated at 70 µm (given by laser waist) have been achieved. The comparative study of E-FISH measurements with and without a plasma discharge, operated at 4 kHz, reveal the presence of a persistent counter electric field, which is assumed to be caused by charge accumulation in between the AlN dielectrics used. Furthermore, by studying the influence of the applied voltage, the pressure, and the inter-dielectric distance, measurements seem to indicate the presence of charges remaining also in the post-discharge volume from the previous discharge to the next one.
Enhanced efficiency of deep ultraviolet light-emitting diodes utilizing full-coverage Al reflector and highly reflective Ni/Rh p-electrode
Authors: Lv Zhenxing , Liao Zhefu , Zhou Shengjun 
Published: April 2024

Abstract
Increasing the reflection of p-side is an effective way to improve the optoelectronic performance of flip-chip light-emitting diodes (FCLEDs). Here, we propose a full-coverage Al reflector (FAR) and a highly reflective Ni/Rh p-electrode to enhance the performance of deep ultraviolet (DUV) FCLEDs. The physical mechanism for the impact of the FAR and Ni/Rh electrode on the light extraction efficiency (LEE) is discussed theoretically. Simulations demonstrate that the combination of the FAR and Ni/Rh electrode improves the LEEs of transverse electric- and transverse magnetic-polarized light by 13.62% and 27.08%, respectively. At an injection current of 100 mA, the fabricated DUV FCLEDs with FAR and Ni/Rh electrode exhibits an external quantum efficiency of 4.01% and a wall plugging efficiency of 2.92%, which are 16.85% and 13.18% higher than those of conventional DUV FCLEDs, respectively. These results support the promise of the FAR and Ni/Rh electrode for high-power DUV LED applications.
Exact solutions to the fractional complex Ginzburg-Landau equation with cubic-quintic and Kerr law nonlinearities
Authors: Yang Liu , Gao Ben 
Published: April 2024

Abstract
The fractional complex cubic-quintic Ginzburg-Landau equation (FCCQGLE) with variable coefficients is a propagation model of optical pulses in optical fibers, the quintic term contained in it not only explains the physical significances that are not found in the existing models, but also has more abundant dynamic characteristics compared with lower dimensional systems. In this paper, the exact solutions of this equation are obtained via the appropriate transformations methods, which also are divided into different kinds. More precisely, we acquire the solitary, soliton and elliptic waves solutions by using the improved unified method, the bright and dark solitons solutions by using the improved F-expansion method, as well as the traveling wave solutions through the improved

(
G
′

/

G

2

)

-expansion and Bernoulli sub-equation function methods. Furthermore, we draw the 3D, 2D, density and contour plots to understand the propagation forms and the changes of amplitudes, frequencies and shapes of the solutions for the FCCQGLE with variable coefficients. The last thing worth mentioning is that the improved unified method here extends the degree of the polynomial from n to -n in the hypothetical solutions, which is not appeared before.
Functionalization of morphology in optimization of dielectric, electrical/impedance modulus, and relaxation mechanisms of Co-Ni doped M-type Sr nanoferrites
Authors: Naqvi Sayed Tathir Abbas , Singh Charanjeet , Godara Sachin Kumar , Jotania Rajshree B , Kaur Varinder , Sood Ashwani Kumar 
Published: April 2024

Abstract
In this article, novel M-type hexaferrites SrCoxNixFe12−2xO19 were synthesized using the sol–gel method. The phase structure was characterized by x-ray diffraction, grain morphology was investigated from scanned electron micrographs, and dielectric/electric/impedance characteristics were analyzed in the frequency range of 100 Hz to 2 MHz. X-ray diffraction (XRD) revealed the formation of hexaferrites without any secondary phase. The grain size and distribution were significantly affected by Co-Ni dopants and there was an observation of cluster of grains, grain agglomerates, and improved inter-grain connectivity. The substitution of Co-Ni caused a reduction in crystallite size from 41.47 to 23.14 nm and the dielectric constant/loss tangent varied non-monotonically. The electric modulus indicated a non-Debye type relaxation and the charge transport mechanism exhibited conductivity relaxation to be more dominant than dielectric relaxation. The prepared ferrites show a large dielectric constant and hence are suitable for use in transformer core and storage media. The correlation of simulated grain/grain boundary parameters with morphology, dielectric parameter, and electric modulus has been presented.
Simultaneously probing the sound speed and equation of state of the early Universe with pulsar timing arrays
Authors: Liu Lang , Wu You , Chen Zu-Cheng 
Published: April 2024

AbstractRecently, several major pulsar timing array (PTA) collaborations have assembled strong evidence for the existence of a gravitational-wave background at frequencies around the nanohertz regime. Assuming that the PTA signal is attributed to scalar-induced gravitational waves, we jointly employ the PTA data from the NANOGrav 15-year data set, PPTA DR3, and EPTA DR2 to probe the conditions of the early Universe. Specifically, we explore the equation of state parameter (w), the reheating temperature (Trh), and the sound speed (cs), findingw= 0.59+0.36-0.40(median + 90% credible interval), andTrh≲ 0.2 GeV at the 95% credible interval for a lognormal power spectrum of the curvature perturbation. Furthermore, we compute Bayes factors to compare different models against the power-law spectrum model, effectively excluding the pressure-less fluid domination model. Our study underscores the significance of scalar-induced gravitational waves as a powerful tool to explore the nature of the early Universe.
The v

R
-philic scalar dark matter
Authors: Xu Xun-Jie , Zhou Siyu , Zhu Junyu 
Published: April 2024

Abstract
Right-handed neutrinos (v

R
) offer an intriguing
portal to new physics in hidden sectors where dark matter (DM) may
reside. In this work, we delve into the simplest hidden sector involving
only a real scalar exclusively coupled to v

R
, referred to
as the v

R
-philic scalar. We investigate the viability of the
v

R
-philic scalar to serve as a DM candidate, under the constraint
that the coupling of v

R
to the standard model is determined
by the seesaw relation and is responsible for the observed DM abundance.
By analyzing the DM decay channels and solving Boltzmann equations,
we identify the viable parameter space. In particular, our study reveals
a lower bound (2.6 × 105 GeV) on the mass of v

R
for
the v

R
-philic scalar to be DM. The DM mass may vary from sub-MeV
to sub-GeV. Within the viable parameter space, monochromatic neutrino
lines from DM decay can be an important signal for DM indirect detection.
Simulations of gravitational heating due to early matter domination
Authors: Ganjoo Himanish , Sten Delos M. 
Published: April 2024

Abstract
In cosmologies with an early matter-dominated era (EMDE) prior to Big Bang nucleosynthesis, the boosted growth of small-scale matter perturbations during the EMDE leads to microhalo formation long before halos would otherwise begin to form. For a range of models, halos can even form during the EMDE itself. These halos would dissipate at the end of the EMDE, releasing their gravitationally heated dark matter and thereby imprinting
a free-streaming cut-off on the matter power spectrum.
We conduct the first cosmological N-body simulations of the formation and evaporation of halos during and after an EMDE.
We show that in these scenarios, the free-streaming cut-off after the EMDE can be predicted accurately from the linear matter power spectrum. Although the free streaming can erase much of the EMDE-driven boost to density perturbations, we use our findings to show that the (re-)formation of halos after the EMDE nevertheless proceeds before redshift ∼ 1000. Early-forming microhalos are a key observational signature of an EMDE, and our prescription for the impact of gravitational heating will allow studies of the observational status and prospects of EMDE scenarios to cover a much wider range of parameters.
Period-multiplying pulses generation by total self-mode-locking of Nd:YVO4 lasers
Authors: Xu M M , Li Z R , Hu M , Ji Y Y , Bi M H , Li H Z , Zhou X F , Pan S Q , Liu C 
Published: April 2024

Abstract
We experimentally demonstrated the phenomenon of period-multiplying pulses in the self-mode-locking Nd:YVO4 laser. With a fixed cavity length of 50 mm and the input mirrors in the resonator with radii of curvature of 100 mm, 200 mm, and 500 mm, the mode-locked pulses with pulse periods 4 times, 6 times and 10 times the fundamental mode-locked pulse period are observed respectively. Besides, by tilting the angle of the output mirror to control the spatial distribution of transverse modes, the switching between the period-multiplication state and its harmonic self-locking state can be achieved. Numerical simulations further confirm that this period-multiplying phenomenon results from the simultaneous locking of multi-longitudinal and multi-transverse modes. This study is of great significance for understanding the complex transverse dynamics in the self-mode-locking lasers.
On an X-ray 3-block Laue-interferometer with violation of ideal geometry
Authors: Mkhitaryan S.A. , Margaryan H.G. , Vasilyan M.S. , Drmeyan H.R. 
Published: April 2024

Abstract
An X-ray monolithic 4-block interference system has been developed and manufactured, in which the first 3 blocks are thin and form a 3- block Laue interferometer with disrupted geometry, and the 4th additional block is thick and is in the reflection position. It is shown that fine structures of interference patterns registered from 3-block interferometers with thin blocks and distorted geometry are observed in cases where an additional 4th thick block is used. The calculations show that when the ideal geometry of a 3-block interferometer is violated, an interference pattern is formed in the form of families of parallel stripes (lines) on the recording plate lying perpendicular to the incident beam. The coordinates of the interference stripes maxima, their periods, as well as the coefficient of a linear enlargement in the presence and absence of the 4th thick block, are calculated. It has been experimentally proven that a thick block does not introduce new information into the interference pattern, but will only enlarge its dimensions in the scattering plane. The limits for reducing the period of interference stripes and their complete disappearance are determined depending on the size of violations from the ideal geometry of a 3-block interferometer.
Laser and microwave instrumentation for ITER and future reactors
Authors: Vayakis G. ,   the ITER diagnostics teams
Published: April 2024

Abstract
ITER diagnostics include an extensive set of
laser and microwave diagnostics to give access to a wealth of information on the
core and edge plasma and to support high performance operation of ITER. For
example, Core and Edge Thomson scattering systems build detailed density and
temperature profiles on time scales much faster than τ
E
to follow transient
events; ECE and reflectometry add time resolution to follow MHD
events. Implementing these diagnostics is challenging, needing a panoply of
technologies to keep them functioning reliably for thousands of hours despite
extreme events such as disruptions and wall conditioning cycles. Shielding,
shutters and cleaning systems protect the forward elements of most optical
systems from the build-up of deposits and damage. Still, plasma-facing mirrors
must survive laser loads and endure erosion, deposition and in-situ RF
cleaning. Calibration and monitoring systems ensure accurate and drift-free
operation. These support systems are also not straightforward and required
specific R&amp;D. Access also drives the design: to deal with the neutron
and gamma sources yet allow maintenance of activated components, ITER uses
large, multi-purpose ports that couple otherwise distinct systems into modules
for maintenance. Machine movement requires provisions to maintain alignment and
calibration, from these port plugs, shown in figure 1, to the
accessible areas 10–50 m away. A final complication comes from the difficulty of
employing electronics near the plugs. Extensive qualification for radiation
resistance is needed. This paper examines design adaptations that ITER adopted
for its near-reactor environment, consider the lessons learnt from the ITER
design activity specifically for laser and microwave systems and lays out some
possible evolution paths for the reactor diagnostician that must follow a more
industrial approach.