bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of the formation of fuzzy tungsten in a HiPIMS plasma system
Authors: Ali Zeyad , Bahri Mounib , Bilton Matthew , Bradley James W
Published: January 2024

Nanostructured ‘fuzzy’ tungsten has been grown for the first time in a high-power impulse magnetron sputtering high power-impulse magnetron sputtering-(HiPIMS) system. The fuzzy layers were formed over range of surface temperatures T
s, from 1025 to 1150 K, for helium ion fluences of 5.02 × 1024 m−2, and mean ion bombardment energy of 55 eV. The time-evolution of the helium ion flux (ΓHe) and incident energy (E
He) were determined during the HiPIMS pulse (of width of 150 μs) using a planar Langmuir probe. The micrographic findings revealed that, the thickness of HiPIMS-grown nano-tendrill layers increased by 83% (from 274 to 501 nm) for only a 125 K rise in T
s. This result is explained by the fact that higher surface temperatures led to larger helium bubbles which ultimately produce a thicker nanostructured layer. The growth rate of fuzzy tungsten layers in HiPIMS conditions is approximately 50% lower than those observed for DC magnetron operation.
The heat dissipation path of self-heating effects for the SOI MOSFET by considering the BOX layer and the TiN barrier layer
Authors: Li Y F , Xu L D , Ni T , Wang J J , Gao L C , Li D L , Wang J J , Ma Q G , Wang Z J , Zeng C B , Li B , Luo J J
Published: January 2024

Silicon-on-insulator devices are widely utilized in high-performance and high-reliability fields, facing challenges from self-heating effects (SHEs). However, research on the heat dissipation path closely related to SHEs remains incomplete. This paper initiates an in-depth analysis of thermal effects involving the fine structures within the heat dissipation path, using ultrafast pulse I–V measurements combined with thermal simulations. It is found in practical processes that the SHEs of scaled-down devices decreased by 40% rather than increased. Research shows the improvement is attributed to the reduction in the thickness of the buried oxide layer between different generations of processes, and the decrease in thermal sensitivity. Based on the two-stage SHE mechanism, the study clarifies for the first time that the box layer mainly affects first-stage heat dissipation, and the main timescale of impact is about the first 100 ns. In addition, the heat dissipation contact capability can effectively affect the temperature rise of first-stage SHEs. For the first time, we reveal that the TiN barrier layer with low thermal conductivity is the key factor limiting heat dissipation through contact. This study represents the crucial step toward a comprehensive investigation of SHEs, offering substantial support for device modeling.
Stabilization and helicity control of hybrid magnetic skyrmion
Authors: Akhir Muzakkiy P M , Suprayoga Edi , Cahaya Adam B
Published: January 2024

The hybrid skyrmion, a type of magnetic skyrmion with intermediate helicity between Bloch and Néel skyrmion, has gained more attraction. It is tolerant toward the skyrmion Hall effect and a potential candidate for quantum bits. We investigated the stabilization and helicity control of the hybrid skyrmion in a two-dimensional magnetic system using an analytical model and micromagnetic simulation. We look at the interplaying factors of the bulk (Db
) and interfacial (Di
) Dzyaloshinskii–Moriya interactions (DMI) along with the dipolar interaction. We show that the hybrid skyrmion can stabilize through the interplay between interfacial DMI and either bulk DMI or dipolar interaction. We can also control the helicity of the hybrid skyrmion by tuning the ratio of

D
i

/

D
b

when there is no dipolar interaction, or simply by adjusting the Di
when the Db
is absent. Our results suggest that hybrid skyrmions can exist within

0
<

|

D
i

|

<
0.4

mJ m−2 for Co-based magnetic systems.
Synthesizing high performance LNMO cathode materials with porous structure by manipulating reynolds number in a microreactor
Authors: Liu Tongli , Deng Hongjie , He Fa , Wu Yuqing , Wu Zhenguo , Wan Fang , Chen Ting , Xu Wenhua , Song Yang , Guo Xiaodong
Published: January 2024

The demand for Lithium-ion batteries (LIBs) has significantly grown in the last decade due to their extensive use electric vehicles. To further advance the commercialization of LIBs for various applications, there is a pressing need to develop electrode materials with enhanced performance. The porous microsphere morphology LiNi
x
Mn2–x
O4 (LNMO) is considered to be an effective material with both high energy density and excellent rate performance. Nevertheless, LNMO synthesis technology still has problem such as long reaction time, high energy consumption and environmental pollution. Herein, LNMO microsphere was successfully synthesized with short precursors reaction time (18 s) at 40 °C without using chelating agent by microreaction technology combined solid-state lithiation. The optimized LNMO cathode shows microsphere (∼8 μm) morphology stacked by nano primary particles, with abundant mesoporous and fully exposed low-energy plane. The electrochemical analysis indicates that the optimized LNMO cathode demonstrates 97.33% capacity retention even after 200 cycles at 1C. Additionally, the material shows a highly satisfactory discharge capacity of 92.3 mAh·g−1 at 10C. Overall, microreaction technology is anticipated to offer a novel approach in the synthesis of LNMO cathode materials with excellent performance.
Normalized ground states for the Sobolev critical Schrödinger equation with at least mass critical growth
Authors: Li Quanqing , Rădulescu Vicenţiu D , Zhang Wen
Published: January 2024

In the present paper, we investigate the existence of ground state solutions to the Sobolev critical nonlinear Schrödinger equation

−
Δ
u
+
λ
u
=
g

u

+

|

u

|

2
∗

−
2

u
 
 
in

R

N

,

∫

R

N

|

u

|

2

d
x
=

m
2

,

where

N
⩾
3

, m > 0,

2
∗

:=

2
N

N
−
2

, λ is an unknown parameter that will appear as a Lagrange multiplier, g is a mass critical or supercritical but Sobolev subcritical nonlinearity. With the aid of the minimization of the energy functional over a linear combination of the Nehari and Pohozaev constraints intersected with the product of the closed balls in

L
2

(

R

N

)

of radii m and the profile decomposition, we obtain a couple of the normalized ground state solution to

(

P
m

)

that is independent of the sign of the Lagrange multiplier. This result complements and extends the paper by Bieganowski and Mederski (2021 J. Funct. Anal.
280 108989) concerning the above problem from the Sobolev subcritical setting to the Sobolev critical framework. We also answer an open problem that was proposed by Jeanjean and Lu (2020 Calc. Var. PDE
59 174). Furthermore, the asymptotic behavior of the ground state energy map is also studied.
LA-Net: layer attention network for 3D-to-2D retinal vessel segmentation in OCTA images
Authors: Yang Chaozhi , Li Bei , Xiao Qian , Bai Yun , Li Yachuan , Li Zongmin , Li Hongyi , Li Hua
Published: January 2024

Objective. Retinal vessel segmentation from optical coherence tomography angiography (OCTA) volumes is significant in analyzing blood supply structures and the diagnosing ophthalmic diseases. However, accurate retinal vessel segmentation in 3D OCTA remains challenging due to the interference of choroidal blood flow signals and the variations in retinal vessel structure. Approach. This paper proposes a layer attention network (LA-Net) for 3D-to-2D retinal vessel segmentation. The network comprises a 3D projection path and a 2D segmentation path. The key component in the 3D path is the proposed multi-scale layer attention module, which effectively learns the layer features of OCT and OCTA to attend to the retinal vessel layer while suppressing the choroidal vessel layer. This module also efficiently captures 3D multi-scale information for improved semantic understanding during projection. In the 2D path, a reverse boundary attention module is introduced to explore and preserve boundary and shape features of retinal vessels by focusing on non-salient regions in deep features. Main results. Experimental results in two subsets of the OCTA-500 dataset showed that our method achieves advanced segmentation performance with Dice similarity coefficients of 93.04% and 89.74%, respectively. Significance. The proposed network provides reliable 3D-to-2D segmentation of retinal vessels, with potential for application in various segmentation tasks that involve projecting the input image. Implementation code: https://github.com/y8421036/LA-Net.
NV centres by vacancies trapping in irradiated diamond: experiments and modelling
Authors: Santonocito S , Denisenko A , Stöhr R , Knolle W , Schreck M , Markham M , Isoya J , Wrachtrup J
Published: January 2024

Advances in applications of nitrogen-vacancy (NV) spin centres in diamond for sensing and quantum metrology depend critically on the NV fabrication methods. One such technique combines epitaxial diamond growth and electron or ion irradiation (He, C, etc), where NVs are activated by vacancy trapping at the nitrogen donor atoms upon thermal diffusion. In this work we study the efficiency of such method by analyzing NV depth profiles created by 340 keV and also 4 keV He irradiation in high purity CVD and HPHT diamond crystals and subjected to sequent annealing at 950 °C and 1200 °C temperatures. This analysis is coupled with the measurement of NV density in the bulk of CVD diamonds with nitrogen doping at low-ppb and low-ppm levels, exposed to MeV electrons in a wide range of the doses. For data analysis we developed an atomistic model based on probabilistic atomic jumps in a crystal lattice, which considers competitive trapping between di-

(

V

2

)

or multi-vacancy defects compared to that of NVs. The efficiency of NV formation was defined as a ratio of the corresponding capture cross sections: σ
NV vs.

σ

V

2

. Applying this model to the experimental data, the

σ

NV

/

σ

V

2

ratio was estimated about 0.1–0.5, where the activation energy of vacancy diffusion of about 1.7 eV was evaluated by 3D localization of individual NVs in depth profiles in a confocal microscope and sampling their spin coherence properties (

T

2

). In addition, we noted two subsidiary effects also discussed here: (i) reduction of NV density within the stopping range of the implanted He atoms after

1200

∘

annealing and, (ii) partial suppression of NVs at near-surface areas visible only at low-dose electron exposures. The results of this study could be helpful to optimize the NV fabrication process reducing the density of ‘collateral’ lattice damage.
Structured quantum collision models: generating coherence with thermal resources
Authors: Cusumano Stefano , De Chiara Gabriele
Published: January 2024

Quantum collision models normally consist of a system interacting with a set of ancillary units representing the environment. While these ancillary systems are usually assumed to be either two level systems or harmonic oscillators, in this work we move further and represent each ancillary system as a structured system, i.e. a system made out of two or more subsystems. We show how this scenario modifies the kind of master equation that one can obtain for the evolution of the open systems. Moreover, we are able to consider a situation where the ancilla state is thermal yet has some coherence. This allows the generation of coherence in the steady state of the open system and, thanks to the simplicity of the collision model, this allows us to better understand the thermodynamic cost of creating coherence in a system. Specifically, we show that letting the system interact with the coherent degrees of freedom requires a work cost, leading to the natural fulfillment of the first and second law of thermodynamics without the necessity of ad hoc formulations.
Powering an autonomous clock with quantum electromechanics
Authors: Culhane Oisín , Kewming Michael J , Silva Alessandro , Goold John , Mitchison Mark T
Published: January 2024

We theoretically analyse an autonomous clock comprising a nanoelectromechanical system, which undergoes self-oscillations driven by electron tunnelling. The periodic mechanical motion behaves as the clockwork, similar to the swinging of a pendulum, while induced oscillations in the electrical current can be used to read out the ticks. We simulate the dynamics of the system in the quasi-adiabatic limit of slow mechanical motion, allowing us to infer statistical properties of the clock’s ticks from the current auto-correlation function. The distribution of individual ticks exhibits a tradeoff between accuracy, resolution, and dissipation, as expected from previous literature. Going beyond the distribution of individual ticks, we investigate how clock accuracy varies over different integration times by computing the Allan variance. We observe non-monotonic features in the Allan variance as a function of time and applied voltage, which can be explained by the presence of temporal correlations between ticks. These correlations are shown to yield a precision advantage for timekeeping over the timescales that the correlations persist. Our results illustrate the non-trivial features of the tick series produced by nanoscale clocks, and pave the way for experimental investigation of clock thermodynamics using nanoelectromechanical systems.
Computation of reverse neighbourhood degree-based topological indices for the transition metal phthalocyanine polymers (poly-TMPc)
Authors: Abirami S Jeyamangala , Raj S Angelin Kavitha , Siddiqui Muhammad Kamran
Published: January 2024

In this article, we discuss the reverse neighbourhood degree-based topological indices for the transition metal phthalocyanine polymers (poly- TMPc). Degree-based topological indices have been extensively studied and linked to a variety of chemical properties. An even more recently established methodology for assessing chemical systems and geometries is the use of numerical descriptors based on the degree of definition defined by the reverse-degree concept technique. It highlights molecular characteristics as numerical descriptors based on the reverse-degree concept’s degree of definition and delivers numerical descriptors in algebraic form. On the other hand, due to their high catalytic activity, photostability, resistance to severe environments, and adaptable properties, transition metal phthalocyanines are a fascinating class of organic semiconductors. Furthermore, different types of reverse neighbourhood topological indices, such as the augmented Zagreb index, first and second Zagreb indexes, and Randi

c

́

indexes, are defined and used to assess the complexity, stability, and other properties of poly-TMPc(m,n).
Multi-zone taylor expansion method for broadband achromatic polarization-insensitive metalens design
Authors: Song Ruixiang , Lu Xutong , Wang Feng , Song Xiyao , Chen Zhangyuan , Li Yanping
Published: January 2024

Broadband achromatic polarization-insensitive metalens with large numerical aperture (NA), large diameter and high efficiency are in demand. Existing methods can dramatically improve one of the above performances at the expense of the others. In this work, the multi-zone Taylor expansion method (MZTEM) is proposed to reduce these trade-offs between different key figures of merit. In this method, a metalens is devided into odd ring and even ring regions, then the odd (even) ring metalens focus peak is shifted forward with tailored functions of even (odd) ring region, and finally the arrangement of the meta-units is optimized to get higher efficiency. Based on the MZTEM, an achromatic polarization-insensitive lithium niobate on insulator (LNOI) metalens is designed working in the visible from wavelength λ = 430 nm to 750 nm, which exhibits a focusing efficiency of 35%–63% and NA of 0.255. Besides, the full width at half maxima (FWHM) variation is less than 0.14 μm and the focusing efficiency variation is less than 2% within 0°–10° incidence angle.
Smart alloy metalized novel photonic NEMS photodiode with CuAlV/n-Si/Al junction structure
Authors: Karaduman Oktay , canbay Canan Aksu , Dere Aysegul , Orman Yusuf , Al-Ghamdi Ahmed A , Al-Sehemi Abdullah G , Yakuphanoglu Fahrettin
Published: January 2024

In this work, a novel smart (shape memory) alloy metalized photonic silicon wafer photodiode with Schottky type CuAlV/n-Si/Al contact structure as a nano-electro-mechanical-system (NEMS) photodevice was fabricated by thermal evaporation technique. The CuAlV memory alloy used as the top Schottky metal contact electrode was produced by arc melting technique and a subsequent quenching in an iced-brine water medium, and its shape memory effect characteristics were revealed by thermal and structural tests. The fabricated photonic NEMS photodiode was characterized by different photo-electrical (I-V, I-t) and frequency/time dependent and illuminated capacitance (C–V/f, C-t, C–V/ill.) and conductance-voltage (G-V) measurements under different frequencies and artificial light intensity power conditions. The I-V tests showed an excellent current rectifying ability and very well net photocurrent generation features of the photodiode. The specific detectivity of the photodiode was found as high as almost approaching 1011 Jones. The SCLC (space charge limited current conduction) analyses made on the double-log I-V plots of the photodiode revealed that the trap-filling TFL-SCLC and trap-free SCLC current conduction mechanisms are the two prevailing conduction mechanisms in the forward bias voltage region. The density of interface states (Dit) of the fabricated photodiode was determined. Moreover, an excellent reproducibility of light-induced photocapacitance formation of the novel photodiode was demonstrated by C–V/t measurements under different artificial light power intensities.
Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas
Authors: Zhang Fengling , Zhang Ling , Zhang Wenming , Cheng Yunxin , Hu Ailan , Ding Xiaobin , Morita Shigeru , Li Zhengwei , Zhou Zhen , Cao Yiming , Ma Jiuyang , Xu Zhehao , Xu Lang , Zhou Chengxi , Jie Yinxian , Mitnik Darío
Published: January 2024

Extreme ultraviolet (EUV) spectra emitted from aluminum in the 5-340 Å wavelength range were observed in Experimental Advanced Superconducting Tokamak (EAST) discharges. Several spectral lines from aluminum ions with different degrees of ionization were successfully observed with sufficient spectral intensities and resolutions using three fast-time-response EUV spectrometers. The line identification uses three independent state-of-art computational codes for the atomic structure calculations, which provide the wavelengths and the collisional and radiative transition rate coefficients. These programs are hullac (Hebrew University—Lawrence Livermore Atomic Code), autostructure, and fac (Flexible Atomic Code). Using three different codes allows us to resolve some ambiguities in identifying certain spectral lines and assess the validity of the theoretical predictions.
Quantum coherence and Rényi mutual information in Heisenberg XYZ system under non-uniform field
Authors: Ye Biaoliang , Zhang Zhanjun
Published: January 2024

We investigate the thermal and magnetic quantum coherence in the Heisenberg XYZ system. To accomplish this, we employ three measures: the L1 norm coherence, the relative entropy coherence, and the Rényi mutual information (RMI). By performing these measures, we can accurately describe the quantum behaviors of the Heisenberg XYZ system. During the process of characterization, we have found both similarities and distinctive properties. Under a non-uniform field, the magnetic field can enhance the RMI for different coefficients α. All of the analytical and numerical results are described in details.
Intracavity heterodyne laser interferometry. Studies of the features of optical Kerr effect in the atmosphere
Authors: Gelikonov V M , Novikov M A
Published: January 2024

The features of high-sensitivity frequency and phase measurements in a He–Ne gas laser at a wavelength of 0.63 μm are considered. The single-frequency mode of this laser with a large excess of the lasing threshold is implemented due to longitudinal mode selection using an ultra-thin nickel metal film placed in the standing field node of the cavity. With such an excess of the lasing threshold, the natural linewidth component is very small (∼10−3Hz), which was determined from the heterodyne method of measuring natural fluctuations of lasing frequency. This method can be used in combination with the multibeam intracavity interferometry for measuring phase modulation at a level of 10−9 rad Hz−1/2. To demonstrate the capabilities of the method, the electro-optical Kerr effect in air at atmospheric pressure in linearly polarized light was studied separately for extraordinary and ordinary waves. The Kerr and the Havelock constants were measured. A deviation from a purely quadratic dependence determined by the fourth power of the amplitude of a low-frequency electric field was found. A possible explanation of the detected deviation from the Kerr effect is the electrostriction.
Comparative analytical and numerical investigation of the plasma density in atmospheric air generated by nanosecond laser pulses
Authors: Delibašić Marković H , Kaleris K , Papadogiannis N A , Petrović V
Published: January 2024

Energy deposition via laser-induced breakdown (LIB) in gases or other media and its accompanying secondary light and sound radiative processes are nowadays increasingly deployed in scientific and technological applications. The modeling and control of the breakdown and radiative processes occurring by the interactions of the free electrons with the heavy particles in the partially ionized medium, requires precise spatio-temporal description of the generated free electron density. This work presents an analysis of a free electron rate model describing the free electron density in air plasmas produced by nanosecond laser pulses. The model accounts for multiphoton and cascade ionization, and for electron diffusion, recombination, and attachment. A closed-form expression of the rate model is derived and validated by comparison with experimentally validated numerical solutions, showing very good agreement in a wide range of parameters. Simulation results are presented for different laser pulses and focal spot sizes and analysis is carried out regarding the dependence of the air plasma on the various laser radiation parameters. The presented approach is particularly useful for complex multi-scale models calculating the electron and ion temperature evolution, the thermoelastic expansion and the shock-wave following LIB of gases.
Non-stationary quasi-classical states of a charged particle in a strong magnetic field under conditions of the dissipative medium
Authors: Sazonov S V
Published: January 2024

Based on the quasi-classical approximation, a general approach is proposed for constructing non-stationary quantum states of a charged particle in a magnetic field, when the dissipative forces of viscous friction and drag, proportional to the velocity and the square of the velocity, respectively, are also significant. The corresponding quasi-classical Green’s function is found, with the help of which the squeezed and coherent states of the particle are studied. It is shown that the dissipation and a magnetic field suppress the quantum properties of the particle. This is especially true for the transverse motion with respect to the magnetic field. Over time, the coherent and squeezed states transform into the same static state, which is characterized by a zero uncertainty of the transverse coordinates and an uncertainty of the longitudinal coordinate, which contains information about the initial velocity of the particle.
Exploration of the ground state properties of neutron-rich sodium isotopes using the deformed relativistic mean field theory in complex momentumrepresentations with BCS pairings*
Authors: Luo 罗 Yu-Xuan 雨轩 , Liu 刘 Quan 泉 , Guo 郭 Jian-You 建友
Published: January 2024

This study explores the ground-state characteristics of neutron-rich sodium isotopes, encompassing two-neutron separation energies, root-mean-square radii, quadrupole moments of proton and neutron distributions, single-particle levels of bound and resonant states, and neutron density distributions and shapes. Simultaneously, special attention is paid to the distinctive physical phenomena associated with these isotopes. The deformed relativistic mean field theory in complex momentum representations with BCS pairings (DRMF-CMR-BCS) employed in our research provides resonant states with real physics, offering insights into deformed halo nuclei. Four effective interactions (NL3, NL3*, PK1, and NLSH) were considered to assess the influence of continuum and deformation effects on halo structures. Calculations for odd-even nuclei 35–43Na revealed the dependence on the chosen effective interaction and number of considered resonant states. Neutron occupation patterns near the Fermi surface, particularly in orbitals

and

, were determined to be crucial in halo formation. The study provided detailed insights into the density distributions, shape evolution, and structure of neutron-rich sodium isotopes, contributing valuably to the field of nuclear physics.
Astrophysical S-factor and reaction rate for 15N(p,γ)16O within the modified potential cluster model*
Authors: Dubovichenko S. B. , Tkachenko A. S. , Kezerashvili R. Ya. , Burkova N. A. , Yeleusheva B. M.
Published: January 2024

We study radiative

capture on the ground state of 16O at stellar energies within the framework of a modified potential cluster model (MPCM) with forbidden states, including low-lying resonances. The investigation of the 15N(

)16O reaction includes the consideration of

resonances due to

transitions and the contribution of the

scattering wave in the p + 15N channel due to the

transition. We calculated the astrophysical low-energy S-factor, and the extrapolated

turned out to be within 34.7−40.4 keV·b. The important role of the asymptotic constant (AC) for the 15N(

)16O process with interfering

(312) and

(962) resonances is elucidated. A comparison of our calculation for the S-factor with existing experimental and theoretical data is addressed, and a reasonable agreement is found. The reaction rate is calculated and compared with the existing rates. It has negligible dependence on the variation of AC but shows a strong impact of the interference of

(312) and

(962) resonances in reference to the CNO Gamow windows, especially at low temperatures. We estimate the contribution of cascade transitions to the reaction rate based on the exclusive experimental data from Phys. Rev. C. 85, 065810 (2012). The reaction rate enhancement due to the cascade transitions is observed from

and reaches the maximum factor ~ 1.3 at

. We present the Gamow energy window and a comparison of rates for radiative proton capture reactions 12N(

)13O, 13N(

) 14O, 14N(

)15O, and 15N(

)16O obtained in the framework of the MPCM and provide the temperature windows, prevalence, and significance of each process.
Simulation and Process Analysis of DLP 3D Printing with High-strength Resin
Authors: Sang Jian , Zhao Xinxin , Jiang Kai , Zhao Qiancheng , Wei Chaofei , Li Ming , Hu Leijun , Jin Changxin
Published: January 2024

By utilizing digital light processing (DLP) printing equipment and technology, this study investigates the temperature field, stress changes, and the impact of various process parameters on the formation and strength characteristics of high-strength resin during the printing process. Abaqus birth-death element method simulation and related process tests are employed for this purpose. The simulation results demonstrate a gradual decrease in the temperature field through wavy diffusion from the center to the boundary during printing. The node temperature, displacement, and stress curves are observed to fluctuate frequently due to the subsequent printing layers, with the maximum stress point located close to the printing platform. The experimental results reveal that the test parameters possess different effects on the surface quality and tensile strength. Inappropriate parameters tend to result in surface defects. The influencing factors on the tensile strength of the sample are ranked in the following order: layer thickness, exposure time, and exposure light intensity. The molded resin sample achieves a tensile strength of 58.5MPa, which is comparable to the tensile properties of traditionally injection-molded parts.
Characteristics of welding laser beam and its influence on weld forming coefficient
Authors: Han Lijun , Jia Lei , Yu Wenchao
Published: January 2024

Laser welding is a very complicated process. At present, there is no systematic research on the relationship between welding parameters and forming coefficient. By studying the internal relationship between laser parameters and the characteristics of welding laser, laser beam indexes, such as focusing index, are defined. They are simplified to a few laser parameters so as to facilitate the study of the influence of welding parameters on the forming coefficient. The results show that material, assembly gap, laser power and welding speed have great influence on weld penetration. When the laser power density reaches 106J/cm2, the characteristics of deep penetration welding appear. Under the condition of constant clearance, the weld depth increases with the increase of t/b. The weld penetration increases with the increase of laser power and tends to be stable when the welding speed is 12mm/s. Different materials also have a certain influence on the weld penetration depth. Under the same conditions, X6CrNiTi1810 obtains greater penetration depth, indicating that physical and chemical properties of materials are also one of the factors affecting the penetration depth. The mechanism and condition of laser welding were analysed. The relationship between laser absorptivity of sheet surface and physical properties of the materials is also studied and then obtained. The study will provide theoretical guidance for laser welding process design and welding parameter selection of steel plate.
Experimental study on enhancement condensation heat transfer in tube by foam metal in presence of non-condensable gas
Authors: Li Luyi
Published: January 2024

Condensation heat transfer in tube is widely applied in industrial production, and the heat transfer process is often weakened by non-condensable gas (NCG) in actual production. Enhancing condensation heat transfer is beneficial to improve production efficiency, which has always been a hot topic in current research. Foam metal material with large specific surface area and good thermal conductivity is an ideal material to enhance heat transfer. In order to study enhancement heat transfer effect and optimize structure of foam metal, this paper investigated condensation heat transfer in tube strengthened by foam metal in presence of NCG experimentally. Section shape of foam metal is annular, and the pores per inch (PPI) of foam metals is 10, 15, 20 respectively. The effects of PPI value, steam/air mixture mass flow, and NCG mass fraction on heat transfer coefficient (HTC) and flow resistance are studied. The results reveal the following: (1) Compared with smooth tube, the foam metal enhances heat transfer significantly, and HTC increases by 1.5-2.3 times. (2) At same steam/air mixture mass flow, 10PPI foam metal tube has the highest HTC compared to others. (3) With increase of NCG mass fraction and PPI value, pressure drop increases and the HTC decreases. Based on experimental data, pressure drop and HTC correlations are developed. This paper provides an important technical basis for foam metal material application in enhancement heat transfer area.
Preparation and photocatalytic performance of TiO2/lignin-based carbon composited photocatalyst
Authors: Xu Qiong , Pan Hong , Zhang Wanting , Xu Lihui , Li Tianyang
Published: January 2024

In this study, the lignin-based carbon/TiO2 (LCT) nanocomposite photocatalyst was prepared by the Sol-gel-carbonization method. The raw material of carbon precursor was lignin extracted from coconut by the solvent heating method. The optimal conditions for lignin extraction, such as material ratio, temperature and time, were investigated. The optimum extraction conditions for lignin were determined as follows: material ratio of 1:7, heating time of 4 hours, and heating temperature of 110 °C. The photocatalytic results demonstrated that the prepared LCT exhibited efficient degradation of MO, achieving a degradation efficiency of up to 91.8% within 2 hours, whereas pure TiO2 showed negligible degradation ability under visible light. Moreover, the LCT composite exhibited good stability during the photodegradation process.
Study on Shear Fatigue Performance of Scarf Repaired Honeycomb Sandwich Structure
Authors: Hao Lei , Gang Qingyong , Wang Xuan , Wang Kuikui , Zheng Yimei
Published: January 2024

The shear static and shear fatigue tests of the honeycomb sandwich composite were carried out to study the effects of three different repair methods on shear fatigue performance: the unilateral panel scarf repair, the unilateral panel and core scarf repair, and the bilateral panel and core scarf repair. The stress ratio R=0.1 was selected. The results show that the failure mode of the honeycomb sandwich structure is the destruction of the honeycomb core. The structure is torn into two halves from the core, and the core tends to squeeze to one side. There is no debonding between the panel and the core, and no delamination in the panel. The static strength, fatigue limit, fatigue life and residual strength of the specimens are significantly decreased by the scarf repair. The rank of reduction from most to least is: the unilateral panel scarf repair, the bilateral panel and core scarf repair, and the unilateral panel and core scarf repair.And the latter two are remarkably similar.
Experimental Study on Effect of Cryogenic Treatment on Cutting Force of Titanium Alloy
Authors: Hua Qinglin , Liu Dong
Published: January 2024

Three titanium alloy materials TA7, TB6 and TC4 were selected, and three titanium alloys with different phases were placed in liquid nitrogen at -196°C for cryogenic treatment, and the change of the cutting performance of titanium alloy samples before and after cryogenic treatment was studied.Six speed combinations of 30m/min, 40m/min, 50m/min, 60m/min, 70m/min and 80m/min were selected to carry out cutting tests.The cutting experiments show that the cutting performance of TA7, TB6 and TC4 titanium alloys has been significantly improved by cryogenic treatment.At different cutting speeds, the cutting force was compared. After cryogenic treatment of three titanium alloy materials, the cutting force was reduced in machining.After cryotreatment, the cutting performance of TB6 was significantly improved, while that of TA7 was relatively low. Among them, TB6 showed the greatest improvement, followed by TA7 and TC4.The three titanium alloys without cryogenic treatment have a cutting speed of 50m/min at maximum cutting force.The maximum cutting force speed of cryogenic titanium alloy is 40m/min.
Research on the Jet Milling Process of Oxidizer for Solid Propellant
Authors: Lu Han , Bai Xinlin , Xu Zhigang , Hou Gengshun , Zhang Zhang
Published: January 2024

The particle size of the oxidizer used by the solid rocket propellant has a great impact on the combustion performance of the grain. In order to study the influence law of the oxidizer used for the jet milling, the jet milling process test system is constructed. The influence of the main process parameters on the average particle size was studied by single-factor test.The orthogonal test was designed, and the prediction model of the relationship between particle size and milling pressure, milling chamber material mass and classification wheel speed was established using multiple linear regression method, and the significance analysis and the prediction test were conducted.The results show that the particle size prediction model is significant, and the classification wheel speed affects the average particle size the most, followed by milling pressure and milling chamber material mass.The conclusion is that the deviation of the milling average particle size under the prediction model acquisition process parameters is between 1.79%∼5.88%, and the prediction model acquisition process parameters can be obtained to mill the AP with the average particle size requirements of different specifications.
Thickness-dependent Evolution of the Ferroelectric Domain in Ultrathin BiFeO3 Films below 10 nm
Authors: Sun Xing-Rui , Meng Jian-Wei , Weng Tsu-Chien
Published: January 2024

The scaling behavior of the ferroelectric domain in thick BiFeO3 has been reported to follow Kittel’s law both theoretically and experimentally. The law collapses at a certain thickness, known as the critical thickness. However, little experimental work focused on the ferroelectric domain evolution behavior in ultrathin BiFeO3 films below 10 nm. In this work, the BiFeO3 films with various thicknesses were prepared and observed with piezoresponse force microscopy (PFM) and the periodicity of the domain was extracted by a two-dimensional fast Fourier transform (2D-FFT). The reciprocal space mapping (RSM) analysis is consistent with PFM results demonstrating the 71° domain of the BiFeO3 films. It is confirmed that the critical thickness in BiFeO3 films is below 5 nm and the domain size decreases with decreasing thickness in accordance with Kittel’s law and a scaling exponent of 0.41 down to that thickness.
Transient liquid phase bonding of Sn-Pb solder with added Cu particles
Authors: Wang Jiaxing , Lin Pengrong , Yao Quanbin , Huang Yinzhuo , Xie Xiaochen , Li Zongyang , Zhang Long
Published: January 2024

In this paper, the 1%-20% Cu particles were uniformly distributed in SnPb solder by mechanical mixing method to prepare composite solder. The solder was welded by eutectic welding and the high temperature failure test was carried out. The melting point and internal structure of solder were observed before reflow, after welding and after aging, and the existence of high-temperature resistant skeleton was found. It could be seen from the DSC curve that the solder absorption peak changes in a step-like manner, and the proportion of the high melting point absorption peak gradually increases with the aging process. The micro-structure of solder joints showed that a thin layer of IMC was formed around the Cu particles in the solder joints after welding, and the IMC in the solder joints had grown continuously until they contacted each other and formed a skeleton structure with aging. The skeleton structure improved the high temperature resistance of the solder joint. EDS analysis showed that the distribution of Cu element in the solder was similar to that of Sn, and the Pb element was enriched. The distribution of metal elements indicates that the solder joint was mainly composed of Cu6Sn5 IMC skeleton and Pb rich phase, and the solder component phase was high melting point component transformation.
Recycling Glass Fiber from Polyurethane Composite by Pyrolysis Strategy with High Mechanical Properties
Authors: Ma Yantao , Du Zhengyu , Fang Xiaojian , Chen Bingbing , Shi Lu , Li Hua
Published: January 2024

With the rapid advancement of the wind power industry, the recycling of retired wind turbine blades and the regeneration of glass fibers have become urgent environmental and economic issues. In this article, a two-step pyrolysis strategy was put forward, in which the relationship between the pyrolysis parameters and the properties of the recycled glass fibers, including the surface morphology, defects, and mechanical properties were demonstrated. We found that pyrolyzing the composites at 500°C under high-temperature water vapor atmosphere to recover the glass fibers, and oxidizing at 450°C to remove the residual carbon of fibers is the optimal choice. In this way, not only can the fibers be recovered from the waste composites, but also the mechanical properties of the fibers can be retained while removing the residual carbon on the surface, which provides a guarantee for subsequent high-value reuse of waste fan blade composite materials.
Effect of specimen thickness on fatigue crack shape evolution for aluminum alloy
Authors: Wu LiMing , He Yuting , Zhang Teng
Published: January 2024

The investigation of fatigue crack propagation and fracture mechanisms in high-thickness metal plates holds pivotal importance in the advancement of a three-dimensional damage tolerance assessment methodology. This research also bears significant implications for ensuring the safe operation of large-scale mechanical equipment. In this study, we examine the influence of specimen thickness on the evolution of fatigue crack shapes in an aluminum alloy. Fatigue crack growth tests were conducted on single-edge notch tension specimens to explore the impact of specimen thickness on the shape of fatigue crack growth. Additionally, we propose a calculation model for crack growth shape based on an energy model in this paper. Both experimental and analytical findings indicate that specimen thickness does indeed exert an influence on fatigue crack shape. Specifically, as the specimen thickness increases, the crack shape transitions from resembling a “fingernail” to a “saddle” shape.
Wetting and interfacial phenomena between a Ni-based superalloy and silica-based ceramic cores with ZrSiO4 additions
Authors: Chen Xiaoyan , Li Zhihui , Zhao Yanjie , Qi Chengkang , Li Shurong , Li Fei
Published: January 2024

Wetting behavior and interfacial reactions between a Ni-based superalloy and silica-based ceramic cores containing 10 wt.%, 30 wt.% and 50 wt.% ZrSiO4 were studied using a sessile drop method. The reaction products were characterized by SEM/EDS, EPMA and XPS analysis. SiO2 was the main component in the ceramic cores taking part in the interfacial reactions and the reaction products were composed mainly of Al2O3 layer with some ZrOx scattered. A Cr2O3 halo formed outside the wetted ceramic surface. The wetting angle increased in the initial stage to a peak value and then decreased to a constant value. The increase of the wetting angle may be attributed to the gas evaporation at the interface and the decrease of the wetting angle was due to the formation of the reaction layer at the interface.
SBC-SNOLAB scintillation system and SiPM implementation for dark matter searches
Authors: Hawley-Herrera H. ,   the SBC collaboration
Published: January 2024

The Scintillating Bubble Chamber (SBC) collaboration is constructing a 10 kg liquid argon (LAr) bubble chamber at SNOLAB called SBC-SNOLAB having the main objective of detecting dark matter. One of the most novel aspects of SBC-SNOLAB is the scintillation system, consisting of LAr doped with on the order of 10 ppm Xe, 48 FBK VUV silicon photomultipliers (SiPMs), the SiPM electronics, two quartz jars, and liquid CF4 used as an hydraulic fluid and additional source of scintillation photons. In contrast with traditional single or dual phase scintillation experiments, the collected LAr scitillation light is used to veto signals which involve the detection of at least a single photoelectron. These proceedings will describe in detail the current SBC-SNOLAB scintillation system which includes the unique design considerations for SBC-SNOLAB that limit the light collection efficiency and the electronics.
Spectroscopic effects of distributed-line phenomena in integrated feedback resistors for charge-sensitive pre-amplifiers
Authors: Capra S. , Secci G. , Pullia A.
Published: January 2024

The distributed capacitive coupling of high-valued resistors with ground planes modifies their effective impedance and power spectral density of noise, especially at high frequency. This effect is clearly visible in poly-silicon resistors inside integrated circuits. When such resistors are used in the feedback network of Charge Sensitive Pre-amplifiers an excess noise arises with a non-white noise spectral density. The effect is a worsening of the spectroscopic resolution. The relevance of such effect with respect to the conventional noise sources is discussed in different practical cases.
Implementation of the frozen-spin technique for the search for a muon electric dipole moment
Authors: Hume Timothy , Chakraborty Ritwika , Doinaki Anastasia , Dutsov Chavdar , Giovannozzi Massimo , Michielsen Katia , Morvaj Ljiljana , Papa Angela , Schmidt-Wellenburg Philipp , Stäger David ,   the muEDM collaboration
Published: January 2024

Applying the frozen-spin technique in a compact
3 T solenoid will enable a search for the muon electric
dipole moment (EDM) with unprecedented sensitivity, improving upon
the current direct limit by approximately a factor of 1000. After
injection of a selected muon, a pulsed magnetic field will reduce
its longitudinal momentum sufficiently to be confined within a
static weakly-focusing magnetic field and maintain a closed circular
orbit. A precisely tuned radial electric field will cancel the spin
precession induced by the muon's anomalous magnetic moment, a = (g - 2)/2, relative to the orientation of the momentum. In this
configuration, the EDM becomes the only remaining inherent source of
relative precession. Asymmetry in the direction and energy of
positrons emitted from muon decay provides an experimental signature
of such precession.

In the first of two phases, 28 MeV/c muons from the πE1 beamline at PSI will be used to demonstrate the systems
necessary for injecting and trapping muons, tuning fields to the
frozen-spin condition and reconstructing positron trajectories.
Designs for the coils producing the pulsed magnetic field and the
electrodes applying the frozen-spin electric field are currently
being evaluated with simulations and prototypes. These systems must
be designed in parallel, especially due to the impact of
eddy-currents induced in the electrodes by the pulsed magnetic
field. The electrode design must minimise eddy-currents to preserve
the field strength of the pulsed field responsible for muon
trapping, while maintaining the electric field uniformity necessary
to achieve the sensitivity goal. This article summarises some of
the efforts underway to address these design challenges.