bluuebunny/crossref_metadata_2025 huggingface dataset:
Generation of chiral optical vortex lattice for controlled aggregation of particles
Authors: Yang X. B. , Zhang H. , Tang M. M. , Ma H. X. , Tai Y. P. , Li X. Z.
Published: July 2024

The chiral light field has attracted great attention owing to its interaction with chiral matter. The generation of chiral light fields with rich structures has become crucial as it can expand application scenarios. Herein, we introduce a chiral optical vortex lattice. As a whole, the optical vortex lattice has a chiral intensity distribution, with each spiral arm having sub-vortices (chiral phase). By using an expansion factor to adjust the involute of a circular lattice, this helical optical vortex lattice can be continuously varied from a circular lattice. The chirality of intensity and phase can be controlled independently. Furthermore, the optical tweezers using the lattice demonstrate the capability of sub-vortices to manipulate particle movement, with the chiral intensity determining the trajectory of particle motion. As the lattice possesses both intensity and phase chirality, it may also find potential applications in tasks such as chiral structure microfabrication.
Normal deformation of a soft lipid-based microtube in response to the flow generated by a tangential motion of a nearby microbead
Authors: Doostaran Mohammad , Hajizadeh Faegheh , Najafi Ali
Published: July 2024

In this study, we experimentally examine the deformation of a micrometer-scale soft membrane in response to a periodic shear flow. We fabricate long and straight cylindrical-shaped soft microtubes from lipid bilayers as part of this study. A microtube with a diameter of about 1–5 μm is moved parallel to its longitudinal axes. At the same time, a polystyrene microbead, trapped by optical tweezers, is forced to stay near the external surface of the microtube. We study the induced shape deformation in the microtube for different shearing parameters. The effects related to the size of the bead, its distance to the surface of the microtube, and their relative speed are analyzed. The overall results qualitatively demonstrate the impact of shearing on the shape of the soft membrane.
Accurate structures and rotational constants of bicyclic monoterpenes at DFT cost by means of the bond-corrected Pisa composite scheme (BPCS)
Authors: Uribe Lina , Lazzari Federico , Di Grande Silvia , Crisci Luigi , Mendolicchio Marco , Barone Vincenzo
Published: July 2024

The structural, conformational, and spectroscopic properties in the gas phase of 20 bicyclic monoterpenes and monoterpenoids have been analyzed by a new accurate, reduced-cost computational strategy. In detail, the revDSD-PBEP86 double-hybrid functional in conjunction with the D3BJ empirical dispersion corrections and a suitable triple-zeta basis set provides accurate geometrical parameters, whence equilibrium rotational constants, which are further improved by proper account of core–valence correlation. Average deviations within 0.1% between computed and experimental rotational constants are reached when taking into account the vibrational corrections obtained by the B3LYP functional in conjunction with a double-zeta basis set in the framework of second-order vibrational perturbation theory. In addition to their intrinsic interest, the studied terpenes further extend the panel of systems for which the proposed strategy has provided accurate results at density functional theory cost. Therefore, a very accurate yet robust and user-friendly tool is now available for systematic investigations of the role of stereo-electronic effects on the properties of large systems of current technological and/or biological interest by experimentally oriented researchers.
Weakly nonlinear analysis of rotating magnetoconvection with anisotropic thermal diffusivity effect
Authors: Nayak Krishnendu , Rani Hari Ponnamma , Rameshwar Yadagiri , Devanuri Jaya Krishna
Published: July 2024

The influence of anisotropic thermal diffusive coefficient on the stability of the horizontal fluid planar layer rotating about its vertical axis and permeated by the horizontal homogeneous magnetic field is studied. The linear stability analysis is carried out using the normal mode method. The stationary cross/oblique and parallel modes are calculated for different ranges of control parameters arising in the system. The SA (Stratification Anisotropy) parameter, α (the ratio of horizontal and vertical thermal diffusivities), plays a key role in deciding the boundaries between these modes and their instability regions when there is a combination of high and low rotation with weak and strong magnetic fields. The obtained isotropic results coincide with those obtained by pioneers in the literature. The weakly nonlinear behavior of the stationary convective motion in the vicinity of primary instability threshold is studied using the two-dimensional Landau–Ginzburg (LG) equation with cubic nonlinearity. This equation derived using the multiple scale analysis is similar to the one obtained in the literature having different relaxation time, nonlinear coefficient, and coherence lengths. These coefficients are used to study the heat transfer rate. In the case of high rotation, Nusselt number gets decreased from atmospheric (α < 1) to oceanic (α > 1) SA types. The domain for secondary instability of Eckhaus is obtained using the spatiotemporal LG equation and it is observed that the Eckhaus instability region decreases with increasing α.
Modeling the electron cyclotron emission radiation signature from suprathermal electrons in a tokamak
Authors: Yu Guanying , Zhu Yilun , Kramer Gerrit , Austin Max , Denk Severin , Yoo Min-Gu , Li Xiaoliang , Zhao Bingzhe , Xie Ruifeng , Li Zeyu , Chen Ying , Liu Xianzi , Qiu Shasha , Luhmann N. C.
Published: July 2024

An Electron Cyclotron Emission (ECE) modeling code has been developed to model ECE radiation with an arbitrary electron momentum distribution, a small oblique angle, both ordinary (O-mode) and extraordinary polarizations (X-mode), and multiple cyclotron frequency harmonics. The emission and absorption coefficients are calculated using the Poynting theorem from the cold plasma dispersion and the electron–microwave interaction from the full anti-Hermitian tensor. The modeling shows several ECE radiation signatures that can be used to diagnose the population of suprathermal electrons in a tokamak. First, in an n = 2 X-mode (X2) optically thick plasma and oblique ECE view, the modeling shows that only suprathermal electrons, which reside in a finite region of the velocity and space domains, can effectively generate cyclotron emissions to the ECE receiver. The code also finds that the O1 mode is sensitive to suprathermal electrons of both a high v⊥ and v‖, while the X2 mode is dominantly sensitive to suprathermal electrons of a high v⊥. The modeling shows that an oblique ECE system with both X/O polarization and a broad frequency coverage can be used to effectively yield information of the suprathermal electron population in a tokamak.
Mixed etching-oxidation process to enhance the performance of spin-transfer torque MRAM for high-performance computing
Authors: Chen Kuan-Ming , Lo Chiao-Yun , Chiu Shih-Ching , Su Yi-Hui , Chang Yao-Jen , Chen Guan-Long , Lee Hsin-Han , Huang Xin-Yo , Shih Cheng-Yi , Wang Chih-Yao , Wang I-Jung , Yang Shan-Yi , Hsin Yu-Chen , Wei Jeng-Hua , Sheu Shyh-Shyuan , Lo Wei-Chung , Chang Shih-Chieh , Tseng Yuan-Chieh
Published: July 2024

Spin-transfer torque magnetic random access memory (MRAM) devices have considerable potential for high-performance computing applications; however, progress in this field has been hindered by difficulties in etching the magnetic tunnel junction (MTJ). One notable issue is electrical shorting caused by the accumulation of etching by-products on MTJ surfaces. Attempts to resolve these issues led to the development of step-MTJs, in which etching does not proceed beyond the MgO barrier; however, the resulting devices suffer from poor scalability and unpredictable shunting paths due to asymmetric electrode structures. This paper outlines the fabrication of pillar-shaped MTJs via a four-step etching process involving reactive-ion etching, ion-beam etching, oxygen exposure, and ion-trimming. The respective steps can be cross-tuned to optimize the shape of the pillars, prevent sidewall redeposition, and remove undesired shunting paths in order to enhance MTJ performance. In experiments, the proposed pillar-MTJs outperformed step-MTJs in key metrics, including tunneling magnetoresistance, coercivity, and switching efficiency. The proposed pillar-MTJs also enable the fabrication of MRAM cells with smaller cell sizes than spin–orbit torque devices and require no external field differing from voltage-controlled magnetic anisotropy devices.
The genome-wide signature of short-term temporal selection
Authors: Lynch Michael , Wei Wen , Ye Zhiqiang , Pfrender Michael
Published: July 2024

Despite evolutionary biology’s obsession with natural selection, few studies have evaluated multigenerational series of patterns of selection on a genome-wide scale in natural populations. Here, we report on a 10-y population-genomic survey of the microcrustacean
Daphnia pulex.
The genome sequences of

>

800 isolates provide insights into patterns of selection that cannot be obtained from long-term molecular-evolution studies, including the following: the pervasiveness of near quasi-neutrality across the genome (mean net selection coefficients near zero, but with significant temporal variance about the mean, and little evidence of positive covariance of selection across time intervals); the preponderance of weak positive selection operating on minor alleles; and a genome-wide distribution of numerous small linkage islands of observable selection influencing levels of nucleotide diversity. These results suggest that interannual fluctuating selection is a major determinant of standing levels of variation in natural populations, challenge the conventional paradigm for interpreting patterns of nucleotide diversity and divergence, and motivate the need for the further development of theoretical expressions for the interpretation of population-genomic data.
A familiar face and person processing area in the human temporal pole
Authors: Deen Ben , Husain Gazi , Freiwald Winrich A.
Published: July 2024

How does the brain process the faces of familiar people? Neuropsychological studies have argued for an area of the temporal pole (TP) linking faces with person identities, but magnetic susceptibility artifacts in this region have hampered its study with fMRI. Using data acquisition and analysis methods optimized to overcome this artifact, we identify a familiar face response in TP, reliably observed in individual brains. This area responds strongly to visual images of familiar faces over unfamiliar faces, objects, and scenes. However, TP did not just respond to images of faces, but also to a variety of high-level social cognitive tasks, including semantic, episodic, and theory of mind tasks. The response profile of TP contrasted with a nearby region of the perirhinal cortex that responded specifically to faces, but not to social cognition tasks. TP was functionally connected with a distributed network in the association cortex associated with social cognition, while PR was functionally connected with face-preferring areas of the ventral visual cortex. This work identifies a missing link in the human face processing system that specifically processes familiar faces, and is well placed to integrate visual information about faces with higher-order conceptual information about other people. The results suggest that separate streams for person and face processing reach anterior temporal areas positioned at the top of the cortical hierarchy.
Analytic solutions for drag and Magnus forces
Authors: Kajiyama Yuji
Published: July 2024

When a spinning object moves in air, it is affected by three forces: the gravitational force, the drag force, and the Magnus force. The equations of motion for such an object are nonlinear, making it difficult to find analytic solutions. Hence, numerical solutions using computers are often preferred. This paper provides two examples of analytic solutions of the equations of motion with the drag and Magnus forces: nearly vertical motion and motion of a light object. In these two cases, we find analytic solutions for the velocity and the position of the object, avoiding mathematical difficulties. It is suitable for university students studying physics.
2D-Bio-FETs for sensitive detection of cardiovascular diseases
Authors: Choudhary Piyush , Singh Vijay K , Dixit Ambesh
Published: July 2024

The biosensing industry has seen exponential growth in the past decade. Impact of biosensors in the current scenario cannot be overlooked. Cardiovascular diseases (CvDs) have been recognized as one of the major causes for millions of deaths globally. This mortality can be minimized by early and accurate detection/diagnosis of CvDs with the help of biosensing devices. This also presents a global market opportunity for the development of biosensors for CvDs. A vast variety of biosensing methods and devices have been developed for this problem. Most of commercially available platforms for CvD detection rely on optical (fluorometric and colorimetric analysis) techniques using serum biomarkers since optical testing is the gold standard in medical diagnosis. Field effect transistors-based biosensors, termed as Bio-FETs, are the upcoming devices for blood or serum analyte detection due to excellent sensitivity, low operational voltage, handheld device structure and simple chip-based operation. Further, the discovery of two dimensional (2D) materials and their integration with conventional FETs has improved the overvoltage problem, sensitivity and strict operating conditions as compared to conventional FETs. Graphene-FETs based biosensing devices have been proven as promising candidates due to their attractive properties. Despite the severe threat of CvDs which has further increased in post-covid era, the Bio-FET sensor studies in literature are still rare. In this review, we aim to provide a comprehensive view of all the multidisciplinary concepts related to 2D-BioFETs for CvDs. A critical review of the different platforms has been covered with detailed discussions of related studies to provide a clear concept and present status of 2D-BioFETs based CvD biosensors.
AFM interlaboratory comparison for nanodimensional metrology on silicon nanowires
Authors: Ribotta Luigi , Delvallée Alexandra , Cara Eleonora , Bellotti Roberto , Giura Andrea , Carlo Ivan De , Fretto Matteo , Knulst Walter , Koops Richard , Torre Bruno , Saghi Zineb , Boarino Luca
Published: July 2024

Silicon nanowires (NWs) with a cylindrical form are fabricated by means of nanosphere lithography and metal-assisted chemical etching to obtain high aspect ratio nanostructures (diameter of about 100 nm and length of more than 15 µm) on an approximately 1 cm2 area. The nanodimensional characterization of individual NWs is performed by using several techniques, because dimensions at the nanoscale strictly relate to functional performance. In this study, we report the results of an interlaboratory comparison between measurements from a metrological atomic force microscope (AFM) and research AFMs located in different national metrology institutes (NMIs) across Europe and in a university. The purpose of this study is to characterize two measurands: (i) sidewall roughness (

R
a

,

R
q

,

R
z

,

R

sk

,

R

ku

parameters) extracted from the top profile measured along the nanowire length, and (ii) diameter of the nanowires measured as top-height. To this goal, the nanowires are spread horizontally on a silicon substrate, which has several areas labelled with a pattern of crosses and letters facilitating the measurement of the same NW, in order to study the reproducibility due to different instruments. Measurements show a good agreement between the different NMIs, with a combined standard uncertainty of top-height diameter less than 3%, and with a combined standard uncertainty of roughness parameters well within 5% for

R
a

and

R
q

values.
Lightweight bearing fault diagnosis method based on cross-scale learning transformer under imbalanced data*
Authors: Zhao Huimin , Li Peixi , Guo Aibin , Deng Wu
Published: July 2024

Due to the limited amount of failure data in rolling bearing faults, traditional fault diagnosis models encounter challenges such as low diagnostic accuracy and efficiency when dealing with imbalanced data. Additionally, many fault diagnosis models are overly complex and demand high computational resources. To address these issues, a lightweight bearing fault diagnosis method based on cross-scale learnable transformer (CSLT) is proposed for imbalanced data. For difficult-to-classify samples, a learnable generalized focal loss function is defined. The learnable parameters are employed to increase its flexibility, it better addresses the issue of bearing fault diagnosis under imbalanced data conditions. Then, a multi-head broadcasted self-attention mechanism is designed by capturing critical local features of the signal through one-dimensional convolution operations, which not only improves feature extraction capability but also reduces computational complexity. Finally, a dynamic label prediction pruning module is developed to trim redundant labels, which helps in lightening the model and enhancing both feature extraction and diagnostic efficiency. The experimental results demonstrate that the proposed diagnosis method exhibits superior diagnostic precision and efficiency by comparing with other methods.
Two-stage re-parameterization and sample disentanglement network for surveillance vehicle detection
Authors: Xie Wei , Liu Weiming , Dai Yuan
Published: July 2024

Detecting vehicles from a surveillance viewpoint is essential, as it has wide applications in community security and traffic control. However, existing methods completely overlook the high memory access costs (MAC) and low degree of parallelism inherent in multi-branch topologies, resulting in significant latency during inference. Additionally, existing methods share the same positive/negative sample set between the classification and localization branches, leading to sample misalignment, and rely solely on intersection-over-union for sample assignment, thereby causing a decrease in detection performance. To tackle these issues, this paper introduces a two-stage re-parameterization and sample disentanglement network (TRSD-Net). It is based on two-stage depthwise to pointwise re-parameterization (RepTDP) and task-aligned sample disentanglement (TSD). RepTDP employs structural re-parameterization to decouple the multi-branch topology during training and the plain architecture during inference, thus achieving low latency. By employing different sample assignment strategies, TSD can adaptively select the most suitable positive/negative sample sets for classification and localization tasks, thereby enhancing detection performance. Additionally, TSD considers three important factors influencing sample assignment. TRSD-Net is evaluated on both the UA-DETRAC and COCO datasets. On the UA-DETRAC dataset, compared to state-of-the-art methods, TRSD-Net improves the detection accuracy from 58.8% to 59.7%. Additionally, it reduces the parameter count by 87%, the computational complexity by 85%, and the latency by 39%, while increasing the detection speed by 65%. Similar performance improvement trends are observed on the COCO dataset.
Valence-state mixing and reduced magnetic moment in

Fe

3
−
δ

GeTe
2

single crystals with varying Fe content probed by x-ray spectroscopy
Authors: Backes D , Fujita R , Veiga L S I , Mayoh D A , Wood G D A , Dhesi S S , Balakrishnan G , van der Laan G , Hesjedal T
Published: July 2024

We present a spectroscopic study of the magnetic properties of

Fe

3
−
δ

GeTe
2

single crystals with varying Fe content, achieved by tuning the stoichiometry of the crystals. We carried out x-ray absorption spectroscopy and analyzed the x-ray circular magnetic dichroism spectra using the sum rules, to determine the orbital and spin magnetic moments of the materials. We find a clear reduction of the spin and orbital magnetic moment with increasing Fe deficiency. Magnetic susceptibility measurements show that the reduction in magnetization is accompanied by a reduced Curie temperature. Multiplet calculations reveal that the Fe2+ state increasingly mixes with a higher valence state when the Fe deficiency is increased. This effect is correlated with the weakening of the magnetic moment. As single crystals are the base material for exfoliation processes, our results are relevant for the assembly of 2D magnetic heterostructures.
Magnetic properties of ferromagnetic nanoparticles of Fe
x
GeTe2 (x = 3, 5) directly exfoliated and dispersed in pure water
Authors: Lim Hyunjong , Ahn Hyo-Bin , Lee Changgu
Published: July 2024

Fe
x
GeTe2 (x = 3, 5) are two-dimensional ferromagnetic (FM) materials that have gained significant attention from researchers due to their relatively high Curie temperature and tunability. However, the methods for preparing FM nanoparticles (FNPs) and large-area Fe
x
GeTe2 films are still in the early stages. Here, we studied the magnetic properties of Fe
x
GeTe2 FNPs exfoliated via wet exfoliation in pure water. The coercive field of Fe3GeTe2 FNPs increases significantly, up to 60 times, while that of Fe5GeTe2 only slightly increases from that of bulk crystals. Further investigation related to the dimension of nanoparticles and the Henkel plot analysis reveals that the variation in their coercive field stems from the material’s thickness-dependent coercive field and the type of term that governs the interaction between single-domain nanoparticles. Our work demonstrates a facile method for preparing FNPs using van der Waals FM materials and tuning their magnetic properties.
Customizing pyridinic nitrogen coordination in Ni–N–C for electrocatalytic CO2 reduction towards CO
Authors: Ai Ying , Zhang Kai , Li Jingde , Du Xiaohang , Wang Yanji , Wu Lanlan , Zhang Zisheng
Published: July 2024

Nickel anchored N-doped carbon electrocatalysts (Ni–N–C) are rapidly developed for the electrochemical reduction reaction of carbon dioxide (CO2RR). However, the high-performanced Ni–N–C analogues design for CO2RR remains bewilderment, for the reason lacking of definite guidance for its structure-activity relationship. Herein, the correlation between the proportion of nitrogen species derived from various nitrogen sources and the CO2RR activity of Ni–N–C is investigated. The x-ray photoelectron spectroscopy (XPS) spectrum combined with the CO2RR performance results show that pyridinic-N content has a positive correlation with CO2RR activity. Moreover, density functional theory (DFT) demonstrates that pyridinic-N coordinated Ni–N4 sites offers optimized free energy and favorable selectivity towards CO2RR compared with pyrrolic-N. Accordingly, Ni–Na–C with highest pyridinic-N content (ammonia as nitrogen source) performs superior CO2RR activity, with the maximum carbon monoxide faradaic efficiency (FECO) of 99.8% at −0.88 V vs. RHE and the FECO surpassing 95% within potential ranging of −0.88 to −1.38 V vs. RHE. The building of this parameter for CO2RR activity of Ni–N–C give instructive forecast for low-cost and highly active CO2RR electrocatalysts.
FreqSNet: a multiaxial integration of frequency and spatial domains for medical image segmentation
Authors: Liu Shangwang , Lin Yinghai , Liu Danyang
Published: July 2024

Objective. In recent years, convolutional neural networks, which typically focus on extracting spatial domain features, have shown limitations in learning global contextual information. However, frequency domain can offer a global perspective that spatial domain methods often struggle to capture. To address this limitation, we propose FreqSNet, which leverages both frequency and spatial features for medical image segmentation. Approach. To begin, we propose a frequency-space representation aggregation block (FSRAB) to replace conventional convolutions. FSRAB contains three frequency domain branches to capture global frequency information along different axial combinations, while a convolutional branch is designed to interact information across channels in local spatial features. Secondly, the multiplex expansion attention block extracts long-range dependency information using dilated convolutional blocks, while suppressing irrelevant information via attention mechanisms. Finally, the introduced Feature Integration Block enhances feature representation by integrating semantic features that fuse spatial and channel positional information. Main results. We validated our method on 5 public datasets, including BUSI, CVC-ClinicDB, CVC-ColonDB, ISIC-2018, and Luna16. On these datasets, our method achieved Intersection over Union (IoU) scores of 75.46%, 87.81%, 79.08%, 84.04%, and 96.99%, and Hausdorff distance values of 22.22 mm, 13.20 mm, 13.08 mm, 13.51 mm, and 5.22 mm, respectively. Compared to other state-of-the-art methods, our FreqSNet achieves better segmentation results. Significance. Our method can effectively combine frequency domain information with spatial domain features, enhancing the segmentation performance and generalization capability in medical image segmentation tasks.
Sex differences in chest electrical impedance tomography findings
Authors: Frerichs I , Händel C , Becher T , Schädler D
Published: July 2024

Objective. Electrical impedance tomography (EIT) has been used to determine regional lung ventilation distribution in humans for decades, however, the effect of biological sex on the findings has hardly ever been examined. The aim of our study was to determine if the spatial distribution of ventilation assessed by EIT during quiet breathing was influenced by biological sex. Approach. 219 adults with no known acute or chronic lung disease were examined in sitting position with the EIT electrodes placed around the lower chest (6th intercostal space). EIT data were recorded at 33 images/s during quiet breathing for 60 s. Regional tidal impedance variation was calculated in all EIT image pixels and the spatial distribution of the values was determined using the established EIT measures of centre of ventilation in ventrodorsal (CoVvd) and right-to-left direction (CoVrl), the dorsal and right fraction of ventilation, and ventilation defect score. Main results. After exclusion of one subject due to insufficient electrode contact, 218 data sets were analysed (120 men, 98 women) (age: 53 ± 18 vs 50 ± 16 yr (p = 0.2607), body mass index: 26.4 ± 4.0 vs 26.4 ± 6.6 kg m−2 (p = 0.9158), mean ± SD). Highly significant differences in ventilation distribution were identified between men and women between the right and left chest sides (CoVrl: 47.0 ± 2.9 vs 48.8 ± 3.3% of chest diameter (p < 0.0001), right fraction of ventilation: 0.573 ± 0.067 vs 0.539 ± 0.071 (p = 0.0004)) and less significant in the ventrodorsal direction (CoVvd: 55.6 ± 4.2 vs 54.5 ± 3.6% of chest diameter (p = 0.0364), dorsal fraction of ventilation: 0.650 ± 0.121 vs 0.625 ± 0.104 (p = 0.1155)). Ventilation defect score higher than one was found in 42.5% of men but only in 16.6% of women. Significance. Biological sex needs to be considered when EIT findings acquired in upright subjects in a rather caudal examination plane are interpreted. Sex differences in chest anatomy and thoracoabdominal mechanics may explain the results.
Studying species distribution in laser-induced plasma by molecular and atomic fluorescence
Authors: Beglaryan Babken G , Zakuskin Aleksandr S , Zaytsev Sergey M , Labutin Timur A
Published: July 2024

The spatial distribution profiles of particles in plasma sources push forward our understanding of plasma evolution and physicochemical processes occuring inside. Optical probe methods, such as laser-induced fluorescence, are advanced tools for spatially resolved plasma studies. In our work, we focused on investigation of distribution of neutral Ca and Fe atoms and CaO and FeO molecules in laser-induced plasma by means of laser-induced fluorescence. The development of excitation-emission schemes for Fe and FeO and the practical implementation of schemes for Ca and CaO allowed us to construct distribution maps of these species in laser plasma at 10 and 100 Torr pressures. Both atomic and molecular fluorescence were observed much further from the plasma formation point than the region of bright spontaneous atomic emission. Additionally, by comparing fluorescence intensity distributions with plasma imaging data, we explain the origin of some pecularities in observable plasma inhomogeneity. Distributions of Ca and CaO fluorescence intensity, as well the distribution of CaO/Ca intensity ratio, demostrate that the monoxide is distributed within the plume by the shock wave, but its concentration in the outer layers of plasma is influenced by recombination with atmospheric oxygen.
Individual quantification of ozone and reactive nitrogen species in mixtures by broadband UV–visible absorption spectra deconvolution
Authors: Huh Seong-Cheol , Bae Jin Hee , Lee Hyungyu , Kim Jinwoo , Choe Wonho , Park Sanghoo
Published: July 2024

Ozone (O3), nitrogen oxides (NO
x
), and reactive nitrogen species (RNS) play critical roles in atmospheric-pressure plasma applications. Although it is crucial to individually quantify these species to understand atmospheric-pressure plasmas and increase their effectiveness, the lack of reliable and cost-effective diagnostics makes this difficult for many researchers. To address this problem, we introduce a new deconvolution method of broadband ultraviolet–visible absorption spectra for the simultaneous measurement of eight species—O3, NO, NO2, NO3, N2O4, N2O5, HONO, and HNO3. Processing of broadband spectra enables deconvolution of similar cross-section profiles and measurement of high densities exceeding the instrumental limit. Novel correction processes enable accurate analysis despite incomplete cross-section data and utilize a priori chemical knowledge to ensure theoretically reasonable results. Two case studies test the efficacy of the method: NO2 and N2O4 equilibria, and reactive species produced by a surface dielectric barrier discharge. With an analysis time of 15–20 ms per spectrum, the measured densities agree well with other theoretical and experimental results, and detection limits on the order of ppmv were achieved with a short path length of 15 cm. This spectral analysis method will facilitate the real-time monitoring of O3, NO
x
, and RNS in many scientific research and industrial applications of atmospheric pressure plasmas.
Quantitative regulation of electron–phonon coupling
Authors: Pei Shenghai , Zhang Zejuan , Jiao Chenyin , Wang Zhenyu , Lv Jian , Zhang Yujun , Huang Mingyuan , Wang Yanchao , Wang Zenghui , Xia Juan
Published: July 2024

Electron–phonon (e–p) coupling plays a crucial role in various physical phenomena, and regulation of e–p coupling is vital for the exploration and design of high-performance materials. However, the current research on this topic lacks accurate quantification, hindering further understanding of the underlying physical processes and its applications. In this work, we demonstrate quantitative regulation of e–p coupling, by pressure engineering and in-situ spectroscopy. We successfully observe both a distinct vibrational mode and a strong Stokes shift in layered CrBr3, which are clear signatures of e–p coupling. This allows us to achieve precise quantification of the Huang–Rhys factor S at the actual sample temperature, thus accurately determining the e–p coupling strength. We further reveal that pressure efficiently regulates the e–p coupling in CrBr3, evidenced by a remarkable 40% increase in S value. Our results offer an approach for quantifying and modulating e–p coupling, which can be leveraged for exploring and designing functional materials with targeted e–p coupling strengths.
Efficient entanglement enhancement of partially entangled pairs
Authors: Harraz Sajede , Cong Shuang
Published: July 2024

We present a comprehensive approach to transform a partially entangled pure state into a maximally entangled state, utilizing only local operations and a single copy of the entangled state. Our approach eliminates the need for multiple copies of entangled states, bilateral operations, and the time-consuming partial-collapse weak measurements. Integrating ancilla qubits, rotation gates, and CNOT gates, we simplify the process of enhancing entanglement, achieving significant efficiency using only a single partially entangled state. Assuming perfect local operations, we showcase the efficacy of our method through both mathematical analysis and the practical implementation of the corresponding circuit in Qiskit. Furthermore, we explore the impact of imperfect local operations, specifically focusing on the CNOT gate and measurement, for a comprehensive analysis. Additionally, we address the case of unknown parameters in the partially entangled pure state and introduce a robust method to effectively handle this uncertainty, ensuring reliable entanglement fidelity optimization in practical situations. We extend our investigation to the application of our method to mixed initial entangled states. Our results demonstrate the reliability of our method in increasing entanglement even in the presence of phase damping and amplitude damping. Additionally, we illustrate its effectiveness in transforming specific mixed initial states in the presence of depolarization into states with enhanced entanglement.
Correction of microwave pulse reflection by digital filters in superconducting quantum circuits
Authors: Guo 郭 Liang-Liang 亮亮 , Duan 段 Peng 鹏 , Du 杜 Lei 磊 , Zhang 张 Hai-Feng 海峰 , Tao 陶 Hao-Ran 浩然 , Chen 陈 Yong 勇 , Yang 杨 Xiao-Yan 小燕 , Zhang 张 Chi 驰 , Jia 贾 Zhi-Long 志龙 , Kong 孔 Wei-Cheng 伟成 , Chen 陈 Zhao-Yun 昭昀 , Guo 郭 Guo-Ping 国平
Published: July 2024

Reducing the control error is vital for high-fidelity digital and analog quantum operations. In superconducting circuits, one disagreeable error arises from the reflection of microwave signals due to impedance mismatch in the control chain. Here, we demonstrate a reflection cancelation method when considering that there are two reflection nodes on the control line. We propose to generate the pre-distortion pulse by passing the envelopes of the microwave signal through digital filters, which enables real-time reflection correction when integrated into the field-programmable gate array (FPGA). We achieve a reduction of single-qubit gate infidelity from 0.67% to 0.11% after eliminating microwave reflection. Real-time correction of microwave reflection paves the way for precise control and manipulation of the qubit state and would ultimately enhance the performance of algorithms and simulations executed on quantum processors.
Origin of the up/down poloidal asymmetric dependence of ELM control in ITER-like RMP configuration in KSTAR
Authors: Choi Inhwan , Liu Yueqiang , In Yongkyoon
Published: July 2024

Recent edge-localized modes (ELM) control experiments via resonant magnetic perturbation (RMP) in KSTAR have shown a strong up/down poloidal asymmetric coupling dependence. Specifically, in lower single null (LSN) plasmas at q95

≳

5, the lower two-row (middle/bottom) RMPs among ITER-like three-row (top/middle/bottom) in-vessel control coils (IVCC) in KSTAR were more effective in suppressing ELM-crashes than the upper two-row (top/middle) RMPs. In contrast, at q
95 ∼ 4, the upper two-row RMPs turned out to be more effective than the lower counterpart. Since the ITER baseline scenario is planned to operate at q
95 ∼ 3, the understanding of the origin of such up/down poloidal asymmetric coupling dependence, as well as the prediction about ITER-relevant conditions at a lower q
95, would be quite important and potentially impactful to the RMP ELM control in ITER. A linear, resistive, single-fluid MHD code MARS-F has been utilized to address and model the up/down poloidal asymmetric RMP coupling dependence. Specifically, based on two contrasting exemplary discharges with up/down poloidal (i) asymmetric at q
95 ∼ 4 and (ii) symmetric behavior at q
95 ∼ 5, among tens of otherwise similar discharges, a systematic MARS-F modeling has been thoroughly conducted. As a result, the plasma response investigation suggests that the X-point displacement (ξ
X), rather than any other figures of merit, would be a directly relevant metric for the up/down poloidal asymmetric coupling in RMP-driven, ELM-crash suppression in KSTAR. Based on a sensitivity study of the edge safety factor in MARS-F modeling, the ξ
X variation follows the same quantitative trend as observed in experiments. However, no or little plasma pressure dependence has been found, though ξ
X increases with plasma pressure. At the ITER-relevant low q
95 ∼ 3 in a scaled KSTAR equilibrium, such modeling predicts the upper two-row RMPs would be more favorable in suppressing the ELM-crashes than the lower counterpart.
Facilitated core-edge integration through divertor nitrogen seeding in the HL-2A tokamak
Authors: Wu N. , Cheng J. , Yi K.Y. , Wang R. , Han M.K. , Huang Z.H. , Wang W.C. , He Y. , Yan L.W. , Du H.L. , Gao J.M. , Ma H.C. , He X.X. , Yang Z.C. , Wen J. , Zhang K. , Wu T. , Guo W.P. , Yu X. , Liu L. , Li Y.G. , Nie L. , Shi Z.B. , Wang D.Z. , Zhong W.L.
Published: July 2024

A divertor detachment with sustainable high-performance plasmas has been achieved through divertor nitrogen seeding in the HL-2A tokamak. The closed divertor structure facilitates achieving high divertor neutral pressure due to its efficient particle containment effect as demonstrated by both experimental and SOLPS simulation results, which aids in achieving the divertor detachment. The radiative divertor is conducive to high-frequency small edge localized modes (ELMs) operation, characterized by a reduced pedestal ion temperature gradient

∇

T

i

and the enhanced electron density gradient

∇

n

e

. The presence of minority nitrogen at the edge plasma, which results from the divertor nitrogen seeding, contributes to the increase of ion temperature

T

i

in the confinement region by suppressing the turbulence through the impurity dilution effect and

E

×

B

shear. The increased ion temperature

T

i

and electron density

n
e

compensate the energy loss resulting from the increased edge radiation during detachment, which contributes to the confinement sustainment combined with reduced pedestal energy loss caused by small ELMs. This work advances our understanding of the fundamental physics governing closed divertor detachment with sustainable high-performance plasmas through divertor nitrogen seeding.
A high-gain high-drive operational amplifier
Authors: Ma Jintao , Liang Jinhui , Li Yanling , He Jiangping
Published: July 2024

This paper presents a high-gain, high-drive operational amplifier based on the 0.18 μm technology. The first stage employs a current-reuse common-source common-gate structure to enhance gain, while the second stage utilizes a transconductance-enhanced push-pull output stage. This design achieves high-drive performance while retaining a high gain. Simulation using Cadence software demonstrates that, under a 5 V power supply voltage, the amplifier exhibits a low-frequency gain of 120 dB, with output sink and source current capabilities reaching 17.7 mA and 2.53 mA, respectively.
Research on Extrusion Forming Process of Micro Internal Thread for Nickel-plated Aluminum Alloy Parts
Authors: Shen Tao , Yang Zaibin , Zhang Liu
Published: July 2024

With the development of electronic products in the direction of miniaturization and lightweight, the specifications of thread gradually become minor, and the high-precision forming of micro threads has become an urgent problem to be solved. In this paper, the extrusion forming process of the micro internal thread was mainly studied on the nickel-plated aluminum alloy parts. The process route suitable for the internal thread forming on electroplated parts was designed, and the key parameters of thread bottom hole diameter and thread tapping speed were determined by experiment. Aiming at the typical problem of internal thread blocked by a broken tap, a thread repair method based on laser ablation was proposed and the laser processing parameters were optimized. Eventually, the manufacturing of M1 micro internal thread on nickel-plated aluminum alloy parts was successfully realized.
A novel gain boost and slew rate enhanced CMOTA
Authors: Zhou Qiang , Ma Jintao , Li Yanling , He Jiangping
Published: July 2024

The design of a novel current mirror operational transconductance amplifier is proposed to address the issues of low gain and limited swing rate under conditions of low voltage and power consumption. In order to improve the gain and swing rate of the amplifier, the increase and lift technology and swing rate increase technology are introduced to the traditional op-amp Simulation and verification based on 0.18 μm BCD process and candence. The results show that under 10 pF load capacitance, the gain is increased by 42 dB and the swing rate is increased by 130 times compared with the conventional transconductance op amp.
Axial flow impeller design and simulation for negative pressure adsorption climbing robot
Authors: Li Mingqiang , Yin Chenggang
Published: July 2024

Axial flow impeller is broadly applied in negative pressure adsorption climbing robots, but its design method and procedure are rarely reported. This paper used a wind turbine blade climbing NDT robot as case study, presented a comprehensive design process of the axial flow impeller, and evaluated the adsorption performance of the impeller by carrying out simulation experiments. Firstly, analysing the force equilibrium of the robot and determining minimum adsorption force required by the robot. Secondly, defining design parameters of the axial flow impeller by using fluid dynamics analysis method. Thirdly, specifying structural parameters of the impeller blades using impeller design theory and developing the CAD model of the impeller. Finally, evaluating the adsorption performance of the impeller by carrying out a series of Fluent simulation experiments. Research results showed that the total adsorption force of the impeller reached 80.30N as rotational speed is 6000rpm, which satisfied design requirements of the climbing robot. This research provides a methodological framework in designing axial flow impellers for the purpose of negative pressure adsorption.
Design of clean energy based microplastic collection device
Authors: Xiong Zhenxi , Luo Yuanming , Wang Kunyang
Published: July 2024

Microplastics are plastic particles with a particle size of less than 5 mm formed after the degradation of plastic by crushing. Microplastics are chemically stable and difficult to degrade, and they are also enriched with chemical poisons, microorganisms, and pathogenic bacteria[1]. Some microplastics migrate with ocean currents in the ocean, affecting the global distribution of pollution and causing great harm to the stability of marine ecosystems and the marine environment. There are a large number of microplastics in the ocean, and the number is increasing[2][3]. In order to realize the microplastic collection function, a microplastic collection device was designed to reduce operational requirements and costs while realizing microplastic salvage. The overall scheme of the system includes the design of subsystems consisting of a solar power generator, a collection mechanism, a filtration device, a buoyancy device, a lighthouse, an anchor device, and so on. According to the actual needs of the microplastic collection, the mechanical structure and dimensions of each subsystem were designed, the 3D modeling of the overall system was completed using SolidWorks, and a physical model of the microplastic collection device was produced for experimental testing.
Simulation for fuselage section with dummies and seats under crash environment
Authors: Zou Jiansheng
Published: July 2024

A numerical model of a commercial fuselage section with dummies and seats under a crash environment was investigated to evaluate the dynamic responses of occupants. Firstly, the two dynamic tests about seats and occupants restraint system were performed to meet the requirements specified by CCAR-25, including the tension loads in straps and the head injury criterion, and gained a method for simulation on seats and occupants restraint system. Secondly, the detail fuselage FE model was built to compare different vertical velocities; the results showed that the greater the velocity is, the more violently the dummies moved, while the deformation of structures had no difference.
Defect identification method for stainless steel welded pipes based on eddy current testing
Authors: Zhang Hengxi , Li Shengtao , Wu Tinghui , An Yuxiang
Published: July 2024

A defect identification and classification method for 316 stainless steel welded pipes is proposed based on eddy current testing technology. Initially, this approach acquires eddy current signals from steel pipes, applies Empirical Mode Decomposition (EMD) to derive Intrinsic Mode Functions (IMFs), chooses the principal IMF based on interrelationships, and extracts time-frequency domain characteristic parameters from the selected IMF. To enhance model recognition efficiency, Principal Component Analysis (PCA) is employed to reduce the dimensionality of the feature vector set. Ultimately, a Support Vector Machine (SVM) is utilized to identify and classify weld defects. The results indicate that this method is highly accurate in identifying defects in 316 stainless steel welded pipes.
Crack initiation life of aviation gear pair
Authors: Liu Yixian , Lin Tengjiao , Chen Bingkui
Published: July 2024

The gear transmission system is an important part of the aero-engine. The most serious fault is tooth root fatigue fracture. This paper mainly discusses the time of fatigue crack initiation stage of aviation gear tooth root position. The crack initiation state can be evaluated by analyzing the root stress. The static contact analysis is solved by using the generated aviation gear pair model. The maximum stress in the bending direction of gear teeth is calculated. The changing pattern of tooth root stress with meshing position is described in detail. According to the multi-axial stress fatigue theory, the surface damage parameters and fatigue life of the gear tooth root position are calculated, and the location of the crack initiation is obtained. Fatigue cracks often appear at half of the gear tooth width and near the tooth root circle.
Maximum Torque Control of Permanent Magnet-Assisted Synchronous Reluctance Motor Using Fuzzy PI
Authors: Wang Fukuan , Sun Baojiang
Published: July 2024

This paper proposes a fuzzy PI-based Maximum Torque Per Ampere (MTPA) control for Permanent Magnet-Assisted Synchronous Reluctance Motor (PMASynRM). The aim is to address issues such as overshooting and slow response in the operation of the PMASynRM by optimizing MTPA control under traditional PI using a fuzzy PI control algorithm. This approach enhances the system’s responsiveness and disturbance rejection capabilities. The article builds a simulation model for the maximum torque-to-current ratio control of PMASynRM using fuzzy PI control in MATLAB/Simulink, comparing it with traditional PI control. Simulation results indicate that the fuzzy PI motor control system exhibits lower overshoot, faster response speed, and better robustness compared to traditional PI control.