bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the exact limits of the real-time equation-of-motion coupled cluster cumulant Green’s functions
Authors: Peng Bo , Pathak Himadri , Panyala Ajay , Vila Fernando D. , Rehr John J. , Kowalski Karol
Published: November 2024

In this paper, we analyze the properties of the recently proposed real-time equation-of-motion coupled-cluster (RT-EOM-CC) cumulant Green’s function approach [Rehr et al., J. Chem. Phys. 152, 174113 (2020)]. We specifically focus on identifying the limitations of the original time-dependent coupled cluster (TDCC) ansatz and propose an enhanced double TDCC ansatz, ensuring the exactness in the expansion limit. In addition, we introduce a practical cluster-analysis-based approach for characterizing the peaks in the computed spectral function from the RT-EOM-CC cumulant Green’s function approach, which is particularly useful for the assignments of satellite peaks when many-body effects dominate the spectra. Our preliminary numerical tests focus on reproducing, approximating, and characterizing the exact impurity Green’s function of the three-site and four-site single impurity Anderson models using the RT-EOM-CC cumulant Green’s function approach. The numerical tests allow us to have a direct comparison between the RT-EOM-CC cumulant Green’s function approach and other Green’s function approaches in the numerical exact limit.
Study of PVAc/EVA polymer series: Influence of the inter-/intra-molecular interaction ratio on the molecular mobility at the glass transition
Authors: Trubert Jules , Matkovska Liubov , Saiter-Fourcin Allisson , Delbreilh Laurent
Published: November 2024

In this work, the molecular mobility at the glass transition of poly(vinyl acetate) (PVAc) and poly(ethylene-co-vinyl acetate) (EVA) amorphous sample series was investigated. The temperature and pressure dependences of the intermolecular interactions were studied from time–temperature–pressure superpositions and from the relaxation time dispersion of the segmental relaxation. The difference in terms of intermolecular interactions due to the lateral group ratio of vinyl acetate (VAc) was then estimated from the activation volume and related to the cooperative behavior. The isobaric fragility and its two contributions (thermal and volumetric) were estimated through high pressure broadband dielectric spectroscopy measurements. The volumetric and thermal contributions show different behaviors as a function of the VAc ratio and as a function of the pressure. Thus, the study of the PVAc/EVA series has allowed us to emphasize that the intramolecular and intermolecular interactions induced by the dipolar pendant groups directly influence the thermal and volumetric contributions to the isobaric fragility.
Effect of para-substituents on NC bonding of aryl isocyanide molecules adsorbed on metal surfaces studied by sum frequency generation (SFG) spectroscopy
Authors: Ito Mikio , Noguchi Hidenori , Uosaki Kohei
Published: November 2024

The effect of para-substituents on the NC bond of aryl isocyanide molecules adsorbed on Au, Ag, Pt, and Pd surfaces was examined by vibrational sum frequency generation (VSFG) spectroscopy. The frequency of NC stretching vibration, υNC, depended on the electronic property of the substituents. When the substituents were more electron-withdrawing and more electron-donating, υNC shifted to lower and higher frequencies, respectively. However, υNC shifted to lower frequency again when the substituents were too electron-donating. The strong dependence of υNC on metal substrates was also observed, reflecting the difference in metal d-band energies, which leads to the difference in the contributions of σ-donation and π back-donation of the NC–metal coupling.
Challenges and solutions in RF sputtering of superconducting Nb for nanostructuring processes
Authors: Strenzke Vincent , Weber Annika , Heydolph Peer , Moch Isa , González Díaz-Palacio Isabel , Hillert Wolfgang , Zierold Robert , Tiemann Lars , Blick Robert H.
Published: November 2024

The growing interest in hybrid devices that combine two-dimensional materials with a superconductor presents new challenges in material deposition. In this study, we demonstrate that achieving excellent superconducting properties by RF (radio frequency) sputtering does not require access to a high-end system but rather depends on the precise control of sputtering parameters and the selection of an appropriate lithographic process. We highlight the challenges and present practical solutions to deposit high-quality niobium thin films for the lithographic production of superconducting hybrid nanostructures. The influence of various deposition parameters, such as power, argon pressure, and film thickness, on the resultant superconducting characteristics can already be deduced at liquid nitrogen temperatures. Furthermore, niobium films tend to degrade when a PMMA [poly(methylmethacrylate)] resist is employed in the fabrication of superconducting nanostructures. We propose alternative and simple strategies to address this issue, which ultimately result in the restoration of the thin-film quality.
Synergistic integration of polarization conversion, absorption, and diffusion in a transparent metasurface for ultra-wideband stealth applications: Optimal design and experimental validation
Authors: Ran Yuzhou , Wu Shuran , Cao Kaicheng , Hou Zhenwei , Zhang Xiaofei , Wang Jianbao
Published: November 2024

This paper unveils a pioneering ultra-wideband metasurface, achieving both optical transparency and significantly reduced scattering, surpassing current stealth material limitations. A novel dual-layer meta-atom, expertly balanced for polarization conversion and absorption, is meticulously fine-tuned through equivalent circuit analysis and a sophisticated genetic algorithm, targeting a broad operational bandwidth. By ingeniously arranging these meta-atoms alongside their mirrored twins, we facilitate an efficient redistribution of scattered cross-polarized energy, leading to substantial reductions in radar detectability. Simulation validations and experimental results affirm a marked improvement in stealth performance, characterized by a co-polarized RCS reduction in excess of 10 dB across the extensive 3.7–25.9 GHz band. This groundbreaking metasurface offers a versatile solution for wideband electromagnetic control in aerospace, telecommunications, and stealth applications, pushing the boundaries of stealth technology.
A Cartesian grid-based model for simulating wave-structure interaction problems
Authors: Fu Hui , Zhang Yunxing
Published: November 2024

The simulation of wave-structure interaction problems is still hard work, especially when the structure is complex and violent phenomena including wave breaking and slamming occur. In this paper, a simple model for simulating violent wave-structure interactions is developed. The decoupling of velocity and pressure is achieved by the fractional step method, and the finite difference method is used for discrete spatial derivatives on a stretched staggered Cartesian grid. A series of schemes that have simple form and preferable stability are adopted in this model. The third-order weighted essentially non-oscillatory scheme is utilized for the advection term, and the free surface is captured with a simple algebraic volume of fluid method named tangent of hyperbola for interface capturing with slope weighting. Triangular elements are utilized to represent the complex body surface, and the volume of solid-based immersed boundary method is utilized to deal with the boundary condition of the body. Therefore, the model is expected to be simple and stable. For the validation of the model, a 5th-order Stokes wave is generated first. Then, solitary waves over a surface-piercing structure and Stokes wave impact on a semi-submersible platform are simulated with the model. Finally, the model is utilized to simulate wave impact on a jacket platform. It is demonstrated that the model is capable of simulating violent wave-structure interactions.
Optimizing numerical performance of enzymatic coagulation models: Insight into proteolysis and gelation dynamics
Authors: Ansari Zeeshan , Rae Mitchell , Kumar Jitendra , Singh Mehakpreet
Published: November 2024

Cheese manufacturing from milk is a meticulous process that transforms casein micelles into various cheeses through enzymatic action and controlled steps. During enzymatic milk coagulation, three key processes occur: enzymatic proteolysis, coagulation, and gelation. Enzymatic proteolysis breaks down milk proteins, leading to coagulation, where the milk thickens. Gelation then forms a gel-like structure that separates curds from whey, essential for cheese production. To model the enzymatic coagulation of milk, a new mathematical framework is derived based on the conservative formulation of the coagulation equation. To solve this nonlinear complex model, an efficient numerical approach utilizing the finite volume scheme is developed. This method features a straightforward mathematical formulation and robustness for implementation on both uniform and nonuniform grids, enhancing its applicability across various scenarios compared to existing approaches [M. Tsagkaridis et al., “Analysis of turbulent coagulation in a jet with discretised population balance and DNS,” J. Fluid Mech. 937, A25 (2022)]. We also discuss the stability condition for the time step to ensure a positive solution. The validation of this new approach involves analyzing number density functions and their integral moments for different gelling and non-gelling kernels. Results indicate that the method captures zeroth and first-order moments with high precision while also computing second-order moments and average micelle sizes formed in the system. Additionally, the impact of the proteolysis constant on gelation is thoroughly examined. This comprehensive capability and detailed analysis provide deeper insight into the enzymatic coagulation process, facilitating its efficient optimization.
Acceleration of rovibrational spectrum calculations through sparsity techniques
Authors: Das Subhasish , Rauhut Guntram
Published: November 2024

The variational calculation of microwave or high-resolution rovibrational spectra is hampered by large memory requirements and long computation times. Simple sparsity techniques, the explicit account of symmetry, and different rotational basis functions have been employed to reduce these computational demands without deteriorating the final spectra. The dependence of the sparsity of the eigenvectors of the rovibrational Hamiltonian matrix with respect to the completeness of the Watson operator has been studied in detail. Benchmark calculations are provided for thioformaldehyde, thioformyl cyanide, and thiopropynal.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: November 2024

Park Systems tailored its Park FX200 to offer precision, reliability, and ease of use in atomic force microscopy on 200 mm samples. Its advanced mechanical structure ensures a lower noise floor, minimal thermal drift, and high stability. Faster Z-servo performance and an improved high-power sample view enhance operational efficiency and imaging capabilities. Features such as automatic probe recognition and probe exchange, laser-beam alignment, and macro-optics for full sample view simplify the user experience and maximize productivity. With optical autofocus, navigation, and sequential measurements at multiple coordinates, combined with automated AFM-scan parameter settings and data analysis, the FX200 streamlines complex operations, making it suitable for both research and industrial applications. Park Systems Inc., 3040 Olcott Street, Santa Clara, CA 95054, USA (408-986-1110) https://parksystems.com
Functional genetics reveals modulators of antimicrotubule drug sensitivity
Authors: Su Kuan-Chung , Radul Elena , Maier Nolan K. , Tsang Mary-Jane , Goul Claire , Moodie Brittania , Marescal Océane , Keys Heather R. , Cheeseman Iain M.
Published: November 2024

Microtubules play essential roles in diverse cellular processes and are important pharmacological targets for treating human disease. Here, we sought to identify cellular factors that modulate the sensitivity of cells to antimicrotubule drugs. We conducted a genome-wide CRISPR/Cas9-based functional genetics screen in human cells treated with the microtubule-destabilizing drug nocodazole or the microtubule-stabilizing drug paclitaxel. We further conducted a focused secondary screen to test drug sensitivity for ∼1,400 gene targets across two distinct human cell lines and to additionally test sensitivity to the KIF11 inhibitor, STLC. These screens defined gene targets whose loss enhances or suppresses sensitivity to antimicrotubule drugs. In addition to gene targets whose loss sensitized cells to multiple compounds, we observed cases of differential sensitivity to specific compounds and differing requirements between cell lines. Our downstream molecular analysis further revealed additional roles for established microtubule-associated proteins and identified new players in microtubule function.
Protein capture performance of microfluidic system: effects of a super hydrophilic coating
Authors: Lu Kuan-Chung , Chen Chun-Wei , Huang Kuan-Yu , Hsiao Yu-Sheng , Yiu Pak-Man , Bai Meng-Yi , Chu Jinn P
Published: November 2024

This paper outlines the coating of polymethylmethacrylate (PMMA) with a 316 stainless-steel (SS) thin film to create a super hydrophilic microfluidic system for the capture of hydrophilic bovine serum albumin (BSA) protein. Scanning electron microscopy and atomic force microscopy images revealed a nanopyramid structure on the SS coating, which significantly increased the surface roughness, compared to that of PMMA. Measurements of water contact angle (6.06°) and PBS contact angle (7.14°) confirmed the super hydrophilic nature of the coated surface. The positive zeta potential of SS (−7.58 mV and −5.2 mV) exceeded that of PMMA (−21.73 mV and −22.78 mV) at pH 6.8 and 7.4, respectively. High surface roughness, super hydrophilicity, and positive surface potential make SS coating an ideal candidate for the capture of BSA protein. In spiral channel experiments, high fluorescence intensity confirmed the efficient capture of BSA. In linear channel experiments, the maximum capture efficiency of SS (72.58%) exceeded that of PMMA and increased in a dose-dependent manner. The excellent protein capture performance can be attributed to the large contact area resulting from a rough surface and correspondingly high surface area-to-volume ratio.
Diagnostic techniques for the interaction of non-thermal atmospheric pressure plasmas and targets
Authors: Sobota A , Garcia-Caurel E , Guaitella O
Published: November 2024

The interaction of non-thermal atmospheric pressure plasmas and targets of various properties is an interdisciplinary area of growing interest. The understanding of the interaction mechanisms between a cold atmospheric pressure plasma and the surface of a liquid or a solid target, as well as the modifications induced inside the target, requires in situ study of these phenomena. Techniques for characterizing the plasma above the target are very well developed but on their own they are not sufficient for understanding the interaction with the target because the target itself must be studied while being under direct exposure to the plasma. The topic of this review are the diagnostic techniques for the characterization of the target in a plasma-target system, performed in situ, while under plasma exposure, time-and space- resolved. Examples also include combining the existing gas-phase techniques with the techniques that traditionally characterize the target in absence of plasma. Many approaches stem from plasma science, but also chemistry, material science, mass transport and fluid dynamics. The possibilities and limitations of the in situ characterization techniques for liquid or solid targets are described, with examples of applications to atmospheric pressure non thermal plasma-target systems.
Engineering the third-order nonlinear optical absorption properties of two-dimensional layered materials
Authors: Lu Chunhui , Li Erkang , Ge Yanqing , Wu Dan , Dong Wen , Wang Yijie , Zhao Lili , Xu Xinlong
Published: November 2024

Two-dimensional (2D) materials have garnered significant attention in the on-chip photonic and optoelectronic applications due to strong light-matter interactions and compatibility with the current planar optoelectronic technology in an atomic thickness. Recent investigation unveiled that 2D materials with prominent interlayer coupling and quantum confinement have shown strong and tunable nonlinear optical (NLO) absorption (saturable absorption (SA), reverse SA, two-photon absorption, etc), which lays a solid foundation for optical circuits, all-optical control as well as ultrafast and Q-switch lasers. In this review, we have outlined the basic theory of third-order NLO absorption for the 2D materials. On this basis, we also summarized the main strategies to modulate and enhance NLO absorption of 2D materials, such as defect engineering, surface termination, crystal phase variation, layer-number control, and heterostructure construction. Finally, the future challenges and outlooks toward engineering NLO properties and further extending and realizing practical photonic and optoelectronic applications based on 2D materials are discussed.
Ohmic contact mechanism and charge redistribution of MoS2/Mn+
1XnO2 heterostructures
Authors: Jiang Xinting , Hou Pengfei , Zhu Gong , Tian Yumiao , Xie Yu , Du Fei , Meng Xing
Published: November 2024

Several M
n+1
X
n
O2 compounds exhibit work functions higher than those of three-dimensional metals, enabling the formation of Ohmic contact heterostructures with MoS2, which enhances the catalytic activity of MoS2 for the hydrogen evolution reaction. However, the Schottky barrier height (SBH) in these Ohmic contact heterostructures does not adhere to the Schottky-Mott limit, leaving the Ohmic contact mechanism between MoS2 and M
n+

1X
n
O2 unclear and hindering further investigations into these heterostructures. In this study, we investigate 22 MoS2/M
n+

1X
n
O2 heterostructures using the unfolding method. Among these, the eight M
n+

1X
n
O2 compounds—Cr2CO2, Mo2CO2, V2CO2, W2CO2, Cr2NO2, V2NO2, Ti3C2O2 and V4C3O2—form p-type Ohmic contacts with MoS2. In contrast, the twelve compounds—Hf2CO2, Nb2CO2, Ta2CO2, Ti2CO2, Zr2CO2, Mo2NO2, Ti2NO2, Ti3N2O2, Zr3C2O2, Nb4C3O2, Ta4C3O2 and Ti4N3O2—create p-type Schottky contacts, while Hf2NO2 and Zr2NO2 form n-type Schottky contacts with MoS2. In the Ohmic contact heterostructures, out-of-plane orbital states hybridize to form a splitting band, allowing the highest valence band of MoS2 to cross the Fermi level and achieve hole doping. This splitting band not only results in a SBH that does not conform to the Schottky–Mott limit but also redistributes charge density. Notably, the heterostructures formed by Cr2CO2, Mo2CO2, V2CO2, W2CO2, Cr2NO2, V2NO2, V4C3O2, and MoS2 exhibit charge polarity distribution, whereas MoS2/Ti3C2O2 does not demonstrate charge polarity distribution.
Electron emission characteristics of cathode micro-protrusion and the comparison with the MG theory analysis
Authors: Li Yuanzhao , Ding Jiangang , Liu Zhiyuan , Geng Yingsan , Wang Jianhua
Published: November 2024

Electron emission from micro-protrusions on the surface of metal electrodes is crucial for vacuum breakdown. The emission characteristics of cathode micro-protrusions and the impact of the space charge effect are investigated in this study, with a comparison to the Murphy–Good (MG) theory analysis. Precise calculations of the emission current density and the Nottingham effect are achieved. A thermal-field emission model for copper micro-protrusion is established to analyze emission characteristics and clarify the mismatches between the results of simulations and MG theory. The results indicate that, for copper micro-protrusions, before breakdown, the emission current is primarily field emission, with thermal emission constituting only 7% of the total. The Nottingham effect results in consistent heating during this phase. The field enhancement factor obtained through the MG theory (γ
MG) is slightly smaller than that derived from the geometric model (γ
geom). This is because γ
geom reflects the characteristics of the apex of the protrusion, while γ
MG reflects the characteristics of the entire electron emission region. The space charge effect bends the MG plot curve and decreases its slope, making it impossible to analyze the emission current using MG theory at this point, which is consistent with the theoretical derivations recorded in the current literature.
CPT-Odd effects on the electromagnetic properties of charged leptons in the standard model extension
Authors: Hurtado-Silva J S , Toscano J J , Vázquez-Hern O
Published: November 2024

The impact of the CPT-Odd electroweak gauge sector of the Standard Model Extension on the electromagnetic properties of charged leptons is studied. This gauge sector is characterized by the

k

1

μ

and

k

2

μ

Lorentz violation (LV) coefficients, which have positive mass dimension because they are associated with a U

Y
(1)-invariant and with an SU

L
(2)-invariant dimension-three operators, respectively. They belong to the category of relevant interactions, which can have strong effects on low-energy observables. We present a comprehensive study on the impact of this sector on the magnetic dipole moment (MDM) and the electric dipole moment (EDM) of charged leptons, up to second order in these LV coefficients, both at the tree and one-loop levels. We find that the O(k

i
) contributions at the tree and one-loop levels depend on energy, while

O
(

k

i

2

)

ones at the tree-level do not. As for

O
(

k

i

2

)

one-loop effects, there are both energy-dependent and energy-independent contributions, but we have focused only on those of the latter type. We find that the EDM only is generated at O(k

i
) up to one-loop level, whereas the MDM receives contributions from both O(k

i
) and

O
(

k

i

2

)

at both tree and one-loop levels. The contributions of O(k

i
) to the MDM are found to be suppressed relative to the corresponding contributions to the EDM by approximately three orders of magnitude. Using a recent experimental limit on the electron EDM the

∣

k
2

0

−
∣

k
2

∣
cos

θ
γ

∣
<
0.86

m
e

bound was obtained. As far as the contributions of

O
(

k

i

2

)

are concerned, we find that the tree-level contributions are suppressed with respect to the one-loop ones by at least a factor of

m

l

2

/

m

Z

2

. We find that the contribution to the electron MDM is by far the dominant one, as it can be up to four and seven orders of magnitude greater than those of the muon and tau, respectively. The Lorentz coefficient

k

AF

μ

of the Carroll–Field–Jackiw’s QED is given by a linear combination of the

k

1

μ

and

k

2

μ

vectors. Assuming that

∣

k

1

2

∣
,
∣

k

2

2

∣
≫
∣

k

AF

2

∣

and taking

k

AF

μ

=
0

, which implies that

k

1

μ

and

k

2

μ

are collinear, we obtain an upper bound of

k

2

2

m

e

2

<
4.36
×

10

−
10

. The fact that

k

2

2

is an observer Lorentz invariant allows us to introduce a new-physics scale through

k
2
2

=

Λ
CPT

, for which we obtain the upper limit ΛCPT < 2.08 × 10−5
m

e
. The physical implications derived from the fact that the LV coefficients have positive mass units are discussed.
Ultrafast optical induction of magnetic order at a quantum critical point
Authors: Fauseweh Benedikt , Zhu Jian-Xin
Published: November 2024

Time-resolved ultrafast spectroscopy has emerged as a promising tool to dynamically induce and manipulate non-trivial electronic states of matter out-of-equilibrium. Here we theoretically investigate light pulse driven dynamics in a Kondo lattice system close to quantum criticality. Based on a time-dependent auxiliary fermion mean-field calculation we show that light can dehybridize the local Kondo screening and induce oscillating magnetic order out of a previously paramagnetic state. Depending on the laser pulse field amplitude and frequency the Kondo singlet can be completely deconfined, inducing a dynamic Lifshitz transition that changes the Fermi surface topology. These phenomena can be identified in harmonic generation and time-resolved angle-resolved photoemission spectroscopy spectra. Our results shed new light on non-equilibrium states in heavy fermion systems.
Online monitoring and fault early warning prediction method for the operational status of steam turbine sliding pin systems
Authors: Li Zongjie , Shi Jiakui , Li Menghui , Fan Shuangshuang , Yao Kun , Wan Jie
Published: November 2024

In modern power systems, ensuring the safe and reliable operation of the sliding pin system in large steam turbine generator sets is crucial. However, the measurable parameters in the current distributed control system are insufficient for fault early detection of the sliding pin system’s operational state. Additionally, there is a lack of relevant research in this area at present. This paper utilizes a typical 300 MW-class unit as a case study. By analyzing the operational mechanism and fault modes of the sliding pin system, a method for online monitoring of its operational status based on cylinder expansion measurement parameters is proposed. Based on this foundation, taking the advantage of long short-term memory (LSTM) network to effectively extract features from univariate time series, and integrating improved particle swarm optimization (IPSO) for automatic hyperparameter optimization, a multi-step prediction model and fault prediction method for the operational status of sliding pin systems based on IPSO-LSTM is designed. Test results based on various performance evaluation metrics indicate that the IPSO-LSTM algorithm significantly enhances the prediction model’s accuracy. Specifically, the TVIWAC-PSO model, which varies the inertia weight (TVIW) and acceleration coefficients simultaneously in the PSO algorithm, optimizes by enhancing global search in the early stages and emphasizing local search in the later stages of iteration. Furthermore, TVIWAC-PSO demonstrates superior performance in optimizing the hyperparameters of the LSTM algorithm. Finally, based on the gap standard between sliding pins and keyway in the actual operating procedures of the unit, combined with the low-pressure cylinder and rotor expansion difference operation standard, thresholds for anomaly detection and early fault prediction of the sliding pin system’s operational status are provided. This study holds significant engineering application value.
Multi-source domain generalization tool wear prediction based on wide convolution weighted antagonism
Authors: Fu Honghao , Li Zisheng , Xiao Xiaoping , Zhou Wenjun , Zhang Kai
Published: November 2024

While traditional deep learning models achieve high accuracy in predicting tool wear under consistent working conditions, actual production processes frequently involve varying conditions due to different processing methods. The wear data of different working conditions have a large difference in distribution, so that the wear signal of milling cutter trained in one working condition can only predict the wear value of the working condition, which will cause a large waste of material and manpower for actual production. Therefore, a domain generalization method utilizing wide deep convolutional neural networks and weighted antagonistic multi-source domain generalization is introduced for tool wear prediction, and multi-source domain wide depth convolutional weighted adversarial domain generalization model (WDCNNWAL) model is constructed. After filtering and de-noising the original data, it is input into WDCNN for automatic feature learning, and the resulting multi-source feature signals are input into the prediction model and discriminator respectively to obtain corresponding loss values. Furthermore, Wasserstein distance is used to measure the probability distribution distance of multi-source feature signals as a weighted value combined with the discriminator loss function, and the final loss value is obtained by adding together. Finally, the tool wear prediction model is set up using a backpropagation neural network. Various milling wear experimental data along with the NASA tool wear public dataset were utilized to assess the predictive performance of the trained model. The model achieves a high level of generalization in tool wear prediction, with average root mean squared error (RMSE) of 0.0599 and 0.2075, as well as average R
2 of 0.9037 and 0.9196 on the NASA and self-collecting datasets respectively. To validate its exceptional precision in generalization performance, comparative experiments were conducted with other data-driven methods resulting in over a 50% reduction in average RMSE and more than a 40% increase in average R
2.
Simultaneous calibration method for rotary axis geometric errors in five-axis dispensing equipment based on monocular vision
Authors: Tang Xianxing , Xiao Linjiao , Zhou Haibo , Wang Ziyang
Published: November 2024

Geometric error calibration of the rotary axis is an important and effective method for improving the five-axis dispensing equipment’s motion and processing accuracy. In most previous studies, simultaneously identifying the geometric errors of multiple rotation axes using traditional precision measuring instruments is often challenging. This paper proposes a simultaneous calibration model based on the AprilTag target visual framework. The model can synchronously identify the geometric errors of the rotation axis in the case of multi-axis linkage. The proposed kinematic calibration model avoids the singularity problem, and the calibration scheme is more economical and capable of unmanned and online calibration. Moreover, the proposed calibration model is compared against the traditional POE error model. In addition, simulation experiments are carried out using different regularization methods regarding the ill-posed problem in the recognition process under visual measurement conditions. Finally, the accuracy and feasibility of the proposed method are verified via experimental results on a five-axis dispensing equipment.
Understanding the competing growth of 2D and 3D transition metal dichalcogenides in a chemical vapor deposition (CVD) reactor
Authors: Ullah Farman , Kazemian Sina , Fanchini Giovanni
Published: November 2024

The competing growth of two-dimensional (2D) and three-dimensional (3D) crystals of layered transition metal dichalcogenides (TMDCs) has been reproducibly observed in a large variety of chemical vapor deposition (CVD) reactors and demands a comprehensive understanding in terms of involved energetics. 2D and 3D growth is fundamentally different due to the large difference in the in-plane and out-of-plane binding energies in TMDC materials. Here, an analytical model describing TMDC growth via CVD is developed. The two most common TMDC structures produced via CVD growth (2D triangular flakes and 3D tetrahedra) are considered, and their formation energies are determined as a function of their growth parameters. By calculating the associated energies of 2D triangular or 3D tetrahedral flakes, we predict the minimum sizes of the critical nuclei of 2D triangular and 3D morphologies, and thereby determine the minimum realizable dimensions of TMDC, in the form of quantum dots. Analysis of growth rates shows that CVD favors 2D growth of MoS2 between 820 K and 900 K and 3D growth over 900 K. Our model also suggests that the flow rates of TMDC precursors (metal oxide and sulfur) in a long, cylindrical CVD reactor are important parameters for attaining uniform growth. Our model provides a compressive analysis of TMDC growth via CVD. Therefore, it is a critical tool for helping to achieve reproducible growth of 2D and 3D TMDCs for a variety of applications.
Quantitative theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy
Authors: Ishida Nobuyuki , Mano Takaaki
Published: November 2024

Theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy (KPFM) measurements has been challenging due to the complexity introduced by tip-induced band bending (TIBB). In this study, we present a method for numerically computing the electrostatic forces in a fully three-dimensional (3D) configuration. Our calculations on a system composed of a metallic tip and GaAs(110) surface revealed deviations from parabolic behavior in the bias dependence of the electrostatic force, which is consistent with previously reported experimental results. In addition, we show that the tip radii estimated from curve fitting of the theory to experimental data provide reasonable values, consistent with the shapes of tip apex observed using scanning electron microscopy. The 3D simulation, which accounted for the influence of TIBB, enables a detailed analysis of the physics involved in KPFM measurements of semiconductor samples, thereby contributing to the development of more accurate measurement and analytical methods.
First principles electron transport in magnetoelectric SrRuO3/BaTiO3/SrTiO3/SrRuO3 interfaces
Authors: Filipoiu Nicolae , Plugaru Neculai , Sandu Titus , Plugaru Rodica , Alexandru Nemnes George
Published: November 2024

Recently, all-oxide ferroelectric tunnel junctions, with single or composite potential barriers based on SrRuO3/BaTiO3/SrTiO3 (SRO/BTO/STO) perovskites, have drawn a particular interest for high density low power applications, due to their highly tunable transport properties and device scaling down possibility to atomic size. Here, using first principles calculations and the non-equilibrium Green’s functions formalism, we explore the electronic structure and tunneling transport properties in magnetoelectric SRO/BTO/mSTO/SRO interfaces, (m = 0, 2, or 4 unit cells), considering both the RuO6 octahedra tilts and magnetic SRO electrodes. Our main results may be summarized as follows: (i) the band alignment schemes predict that polarization direction may determine both Schottky barrier or Ohmic contacts for m(STO) = 0, but only Schottky contacts for m(STO) = 2 and 4 junctions; (ii) the tunnel electroresistance and tunnel magnetoresistance ratios are evaluated at 0 and 300 K; (iii) the most magnetoelectric responsive interfaces are obtained for the m(STO) = 2 heterostructure, this system also showing co-existent giant tunnel electroresistance and tunnel magnetoresistance effects; (iv) the interfacial magnetoelectric coupling is not strong enough to control the tunnel magnetoresistance by polarization switching, in spite of significant SRO ferromagnetism.
Using Excel and VLC Player to examine the takeoff of a Boeing 747-400 ERF
Authors: Bloom Steven D
Published: November 2024

We discuss an in-class activity for introductory mechanics students to examine the forces on an airplane and the resulting path at takeoff using Excel and VLC Player. We use a Euler-based integration method within Excel to predict the takeoff run for a Boeing 747-400 ERF considering forces such as thrust, lift, drag, and friction. We then used VLC Player to analyse a YouTube video of a Boeing 747-400 ERF at takeoff to measure take-off times, distances, velocities, and accelerations. We then compare these data with the predictions. Particularly when the effects of friction are included, the data match the predicted values well for distances and velocities, but the discrepancies are significantly larger for the accelerations, suggesting that a more complex model is required (such as velocity dependence of thrust). We include a video, the detailed instructions for this exercise, and the Excel code as supplementary materials.
Estimation of experimental uncertainties. A simplified proposal for indirect measurements in the laboratory
Authors: Gianino Concetto
Published: November 2024

In physics education, understanding error theory is essential for both epistemological and practical reasons, particularly when students encounter experimental uncertainties in laboratory settings. For direct measurements, when random uncertainties were negligible, the experimental error was estimated using instrumental resolution. However, when significant random uncertainties are present, they are often estimated using a half-range formula. For indirect measurements, the traditional approach involves the error propagation theory, which can be challenging for first-year high school students because of its complexity. An alternative approach involves estimating the experimental uncertainty a posteriori using a half-range formula. This method simplifies error estimation and is more accessible to students, potentially enhancing their comprehension and the application of error analysis in experimental physics.
BD-StableNet: a deep stable learning model with an automatic lesion area detection function for predicting malignancy in BI-RADS category 3–4A lesions
Authors: Qu Hui , Chen Guanglei , Li Tong , Zou Mingchen , Liu Jiaxi , Dong Canwei , Tian Ye , Liu Caigang , Cui Xiaoyu
Published: November 2024

The latest developments combining deep learning technology and medical image data have attracted wide attention and provide efficient noninvasive methods for the early diagnosis of breast cancer. The success of this task often depends on a large amount of data annotated by medical experts, which is time-consuming and may not always be feasible in the biomedical field. The lack of interpretability has greatly hindered the application of deep learning in the medical field. Currently, deep stable learning, including causal inference, make deep learning models more predictive and interpretable. In this study, to distinguish malignant tumors in Breast Imaging-Reporting and Data System (BI-RADS) category 3–4A breast lesions, we propose BD-StableNet, a deep stable learning model for the automatic detection of lesion areas. In this retrospective study, we collected 3103 breast ultrasound images (1418 benign and 1685 malignant lesions) from 493 patients (361 benign and 132 malignant lesion patients) for model training and testing. Compared with other mainstream deep learning models, BD-StableNet has better prediction performance (accuracy = 0.952, area under the curve = 0.982, precision = 0.970, recall = 0.941, F1-score = 0.955 and specificity = 0.965). The lesion area prediction and class activation map results both verify that our proposed model is highly interpretable. The results indicate that BD-StableNet significantly enhances diagnostic accuracy and interpretability, offering a promising noninvasive approach for the diagnosis of BI-RADS category 3–4A breast lesions. Clinically, the use of BD-StableNet could reduce unnecessary biopsies, improve diagnostic efficiency, and ultimately enhance patient outcomes by providing more precise and reliable assessments of breast lesions.
Tooth point cloud resampling method based on divergence index and improved euclidean clustering rule
Authors: Qiu Zhixian , Jiang Jingang , Wu Dianhao , Wang Jingchao , Zhou Shan
Published: November 2024

Objective. In endodontic therapy, 3D cone-beam computerized tomography (CBCT) and oral scan fusion models allow exact root canal channels and guidance. However, the point cloud model from CBCT has few data points and poor model features, limiting 3D fusion with oral scan data. Our aim to build a sub-regional point cloud resampling method and evaluate the precision of merging it with three-dimensional oral scan data. Approach. Two molars and four incisors were resampled for this investigation. Based on point cloud density and curvature, the rebuilt model was separated into the crown and cervical cavities. Using crown surface morphology, Divergence index (DI) was employed to determine resampling points based on point dispersion. Improved Euclidean clustering rule (IECR) downsamples each point using its weight and joins the two halves using Iterative nearest neighbor to create a complete resampled point cloud. After aligning with the oral scanning model, the maximum error, maximum distance, average distance, and other characteristics are calculated to assess resampling. Additionally, a cross-entropy kernel-based point cloud reconstruction depth selection method is given to determine the appropriate reconstruction depth. Main results. Applying the DI-IECR technique reduces the average distance between the resampled tooth point cloud and the point cloud generated by the dental scanner by around 20%. The maximum error remains same to that of the widely used method. This study also demonstrates that the use of the DI-IECR approach guarantees the complete representation of the coronal characteristics of the resampled reconstructed 3D model, rather than excessively focusing processing resources on pertinent but insignificant areas. Significance. Point cloud data and crown features are balanced using DI-IECR. When registered with the oral scan model, CBCT-generated point clouds are more accurate and timely, making them a better intraoperative navigation model.
Noise-reducing quantum key distribution
Authors: Zhang Haoran , Li Wei , He Ruihua , Zhang Yan , Xu Feihu , Gao Weibo
Published: November 2024

Quantum key distribution (QKD) is a swiftly advancing field with the great potential to be ubiquitously adopted in quantum communication applications, attributed to its unique capability to offer ultimate end-to-end theoretical security. However, when transitioning QKD from theory to practice, environmental noise presents a significant impediment, often undermining the real-time efficacy of secure key rates. To uphold the operation of QKD systems, a myriad of protocols and experimental designs have been proposed to counteract the effects of noises. Even with real-time variations, the primary component of environmental noise can be modeled as a unitary evolution or background noise, which can be compensated or reduced with various noise-reducing schemes. This review provides an overview of design strategies for reducing noises in practical QKD systems under various circumstances. These strategies are evaluated based on their principles and suitability in real-world applications. Through this review, we aim to provide readers with a clear understanding of the logic behind these noise-reducing QKD designs, facilitating a smoother start of research and engineering in this field.
Anodizing of iron-based alloys: fundamentals, recent progress, and applications
Authors: Del Olmo Ruben , Tynkevych Olena , Łazińska Magdalena , Syrek Karolina , Durejko Tomasz , Czerwiński Mateusz , Zaraska Leszek , Tiwari Ratnesh , Michalska-Domańska Marta
Published: November 2024

This review aims to comprehensively and systematically analyze the anodic oxidation process to form nanostructured oxide films on the surface of the most technologically relevant Fe-based alloys and steels. A special emphasis is put on detailed analysis of the mechanisms of the anodic formation of Fe-based nanostructured materials. The effect of anodizing parameters including the type of Fe-alloy, electrolyte composition, potential/current regimes, as well as various post-treatment procedures (including annealing treatment) on the growth, morphology, composition, and properties of the resulting oxide films is discussed in detail. Examples of possible applications of the anodic films grown on Fe-alloys in various fields including photocatalysis, energy storage, sensors, biomedicine, and others are also provided. Finally, current trends, challenges, and perspectives in the anodizing of Fe-alloys are addressed.
Enhanced perpendicular magnetic anisotropy energy and Curie temperature in the CrOCl monolayer: strain effects
Authors: Iqbal Asma , Safdar H M W , Algethami Abdullah A , Nazir S
Published: November 2024

Magnetic monolayers offer a wide variety of applications in enhancing the functionalities of storage devices including higher thermal stability, lower power consumption, and higher operation speed, owing to their intrinsic long-range spin ordering. Herein, we study the biaxial ([110]) strain range of ± 5% influence on the formation energetics, electronic structure, and magnetic behaviour of the CrOCl monolayer (ML) based on the ab-initio calculations including spin–orbit coupling (SOC) effects. It is predicted that the system displays an insulating character having an energy band gap (E

g
) of 2.05 eV with a ferromagnetic (FM) ground state in its unstrained state. The estimated partial spin magnetic moment on the Cr ion is +2.7 μ

B
/f.u. (per formula unit) with S = 1.5 and lies in a + 3 oxidation state with an electronic distribution of

t

2
g

3

↑

t

2
g

0

↓

e

g

0

↑

e

g

0

↓

. Along with this, [001] (c-axis) is found to be the easy magnetic axis, which results in a magnetic anisotropy energy (MAE) of 0.2 meV having an MAE constant of 0.25 mJ m−2 and the computed Curie temperature (T

c
) using Ising model is 157 K. Furthermore, the system shows the robustness of the FM insulating behavior against considered strains. However, a significant shift in the conduction band edge (CBE) position to lower energies is evident for tensile strains, which substantially reduces the E

g
up to 13%. The decrease in E

g
value is evidence of higher absorption in the visible range which makes it the best option for optoelectronics and photocatalysis. Simultaneously, our results revealed that strain enhances the MAE and T

c
up to 190% and 43%, respectively. Hence, optimized E

g
, MAE, and T

c
within a considerable strain range, make the CrOCl ML a potential candidate for its utilization in magnetic memory devices.
Design of logic circuits on 5 nm MOS
Authors: Chakraborty Raktim , Mandal Jyotsna Kumar
Published: November 2024

In this research, MOSFET, CMOSFET of gate length 5 nm has been presented. The simulation at gate length of 5 nm has been conducted using three different semiconductor materials which are SiGe, InGaAs and GaN. The comparison among their performance at MOSFET level has been showcased which reveals the better performance of InGaAs among the three different semiconductor candidates which is functioning at threshold voltage of 0.3804 V, drive current of 4.431 × 10−06 A μm−1 and low leakage current of 7.696 × 10−11 A μm−1 respectively. The comparison with the existing MOSFETs have been carried out and validated with ITRS 2013 and IRDS 2020 respectively. In order to design 2 input AND, OR, XOR, XNOR, NAND, NOR and NOT gate circuits, the CMOSFET at 5 nm gate length has been utilised and their performance in terms of Average power, Propagation delay, Power delay product and noise margin analysis are furnished in this paper. A comparison among the proposed work with the existing reveals the lower power consumption, delay and the power delay product of the proposed work.
Surface plasmon resonance refractive index sensor based on D-type ZBLAN photonic crystal fiber
Authors: Jin Zhehao , Guo Ying , Yuan Hengyi , Guo Pengxiao , Zhang Lei , Li Shuguang
Published: November 2024

This study presents a ZBLAN-based D-type photonic crystal fiber (PCF) surface plasmon resonance (SPR) refractive index (RI) sensor. Traditional silica substrate face challenges in detecting high-RI liquids and have limited RI detection ranges. To address this, we utilize high-RI ZBLAN glass as the substrate material and design a cladding with an outer three-layer ortho-octagonal and inner ortho-hexagonal air-hole structure, polished and coated with a gold film to excite SPR. The loss spectrum divides into two resonance channels for RI sensing within 1.420–1.466 and 1.467–1.475. Finite element method analysis evaluates the sensor’s performance, including the impact of air-hole diameter, gold film thickness, air-hole spacing, and polishing depth on the full width at half maximum (FWHM) of the loss spectrum and sensitivity. Results indicate that structural parameter changes primarily affect FWHM, with minimal influence on sensitivity. The two resonance channels achieve maximum sensitivities of 9000 nm RIU−1 and 13000 nm RIU−1, highest resolutions of 1.11 × 10−5 RIU and 7.69 × 10−6 RIU, maximum amplitude sensitivities of 102.11 RIU−1 and 102.51 RIU−1, and Q values of 46.27 and 31.52. This approach offers a promising method for developing high-sensitivity, wide-range RI PCF-SPR sensors, demonstrating strong potential in RI measurement applications.