bluuebunny/crossref_metadata_2025 huggingface dataset:
Axisymmetrical resonance modes in an electrowetting optical lens
Authors: Miscles Eduardo J. , Lim Wei Yang , Supekar Omkar D. , Zohrabi Mo , Gopinath Juliet T. , Bright Victor M.
Published: May 2023

Electrowetting-based adaptive optics are of great interest for applications ranging from confocal microscopy to LIDAR, but the impact of low-frequency mechanical vibration on these devices remains to be studied. We present a simple theoretical model for predicting the resonance modes induced on the liquid interface in conjunction with a numerical simulation. We experimentally confirm the resonance frequencies by contact angle modulation. They are found to be in excellent agreement with the roots of the zero-order Bessel functions of the first kind. Next, we experimentally verify that external axial vibration of an electrowetting lens filled with density mismatched liquids (Δρ = 250 kg/m3) will exhibit observable Bessel modes on the liquid–liquid interface. An electrowetting lens filled with density matched liquids (Δρ = 4 kg/m3) is robust to external axial vibration and is shown to be useful in mitigating the effect of vibrations in an optical system.
Scanning SQUID-on-tip microscope in a top-loading cryogen-free dilution refrigerator
Authors: Zhou Haibiao , Auerbach Nadav , Roy Indranil , Bocarsly Matan , Huber Martin E. , Barick Barun , Pariari Arnab , Hücker Markus , Lim Zhi Shiuh , Ariando A. , Berdyugin Alexey I. , Xin Na , Rappaport Michael , Myasoedov Yuri , Zeldov Eli
Published: May 2023

The scanning superconducting quantum interference device (SQUID) fabricated on the tip of a sharp quartz pipette (SQUID-on-tip) has emerged as a versatile tool for the nanoscale imaging of magnetic, thermal, and transport properties of microscopic devices of quantum materials. We present the design and performance of a scanning SQUID-on-tip microscope in a top-loading probe of a cryogen-free dilution refrigerator. The microscope is enclosed in a custom-made vacuum-tight cell mounted at the bottom of the probe and is suspended by springs to suppress vibrations caused by the pulse tube cryocooler. Two capillaries allow for the in situ control of helium exchange gas pressure in the cell that is required for thermal imaging. A nanoscale heater is used to create local temperature gradients in the sample, which enables quantitative characterization of relative vibrations between the tip and the sample. The spectrum of the vibrations shows distinct resonant peaks with a maximal power density of about 27 nm/Hz1/2 in the in-plane direction. The performance of the SQUID-on-tip microscope is demonstrated by magnetic imaging of the MnBi2Te4 magnetic topological insulator, magnetization and current distribution imaging in a SrRuO3 ferromagnetic oxide thin film, and thermal imaging of dissipation in graphene.
Impact of selective ion transmission on measurement by retarding field analyzer
Authors: Takahashi H. , Seino T. , Nishimura R. , Yoshimura K. , Kanno A. , Hara T. , Takahashi Y. , Kagaya S. , Matsuyama A. , Hayashi Y. , Tobita K.
Published: May 2023

The impact of selective ion transmission on the use of retarding field analyzers (RFAs), which is attributed to the ion Larmor motion, was investigated. Depending on the ion Larmor radius and ion guiding center position, selective transmission limits the parallel and perpendicular ion velocities inside the RFA volume. The velocity limitation flattens I–V curve, leading to an overestimation of the parallel ion temperature. However, the overestimation can be reduced to an acceptable level using the slope in a large grid potential region. The influence of selective transmission depends on both parallel and perpendicular ion temperatures. This nature likely allows the simultaneous determination of two ion temperatures by the best fit of the experimental data, even from a single I–V curve. Applicability of this method was investigated using a radio frequency plasma.
Differential design in homogenous sensors for classification and decoupling kinesthetic information through machine learning
Authors: Zhou Yuanzhi , Xu Weiliang , Ji Yongsheng , Zhou Guoyuan , Wu Wenfeng , Chen Zibin , Wang Beibei , Gui Xuchun , Li Xinming
Published: May 2023

To accurately reflect the movement of humans or robots, multi-sensor integration strategy is necessary to decouple complex deformations caused by motion in the wearable artificial kinesthetic perception system. The multi-sensor integration strategy could collect multi-dimension information, making up for the deficiency of robustness and accuracy of single sensor in complex motion scenes and extending the sensing capability of the system. However, the inevitable inconsistency between multiple sensors causes difficulties in fabrication, integration, and perception, limiting the development of artificial kinesthetic perception systems toward the direction of compact integration, large-area sensing, and high-resolution decoupling. Here, we propose a strategy to build an artificial kinesthetic perception system based on the differential design of homogeneous sensors. The strategy aims at guiding system design to avoid the inconsistency in multi-sensor integration by revealing the explicit relationship among structure, signal, and movements from the perspective of the physics model. According to the strategy, we presented a simple fabrication method of the kinesthetic perception prototype. The prototype with two homogenous sensors (0.019 56 residual on average) shows three differential signal modes to three deformations. With the help of machine learning, it realized the decoupling task to 25 kinds of complex deformations. The accuracy remains at 95% even though the decoupling resolution is up to 0.2 mm. With more than one prototype arrayed, complex deformation composed with more kinds of basic deformation (shear and twist) could be further decoupled. We believe that the strategy described in this paper will contribute to the development of a compact and programmable kinesthetic perception system.
Figure correction of a Wolter mirror master mandrel by organic abrasive machining
Authors: Egawa Satoru , Matsuzawa Yusuke , Hiraguri Kentaro , Motoyama Hiroto , Yamaguchi Gota , Yokomae Shunya , Takei Yoshinori , Kume Takehiro , Owada Shigeki , Tono Kensuke , Yabashi Makina , Hashizume Hirokazu , Mimura Hidekazu
Published: May 2023

In this study, figure correction of a master mandrel of a Wolter mirror by organic abrasive machining (OAM) was demonstrated. In OAM, a flow of slurry, dispersed with organic particles, locally removes the surface of a workpiece in contact with a rotating machining tool. A computer-controlled machining system was used to perform the selective removal of a fused silica surface at a spatial resolution of 200 µm. A master mandrel of a Wolter mirror for soft x-ray microscopes was fabricated with a figure accuracy of <1 nm root mean square, which is sufficient for diffraction-limited imaging at a wavelength of 10 nm.
Bubble growth and departure behavior in subcooled flow boiling regime
Authors: Chitnavis Nikhil , Pothukuchi Harish , Patnaik B. S. V.
Published: May 2023

Understanding the detailed dynamics of bubble ebullition cycle is central to effectively exploit coolant phase change in subcooled flow boiling. In the present study, the bubble growth rate and the bubble departure mechanism in subcooled flow boiling conditions are investigated. The bubble growth rate is estimated by employing an energy balance model, which ensures that the applied wall heat flux contribution to components, such as (i) microlayer evaporation, (ii) conduction through superheated layer region, and (iii) condensation heat transfer, are accounted. The bubble departure diameter and the type of departure (i.e., sliding or lift-off) are predicted using a simple force balance model on the vapor bubble. The implemented models are thoroughly validated against the benchmark experimental data. Furthermore, the influence of operating conditions, viz., pressure (1–3  bar), mass flux (200–1000  kgm−2s−1), heat flux (200–500  kWm−2), and the degree of subcooling (20–30 K) on the bubble dynamics, is investigated for subcooled flow boiling conditions. Based on the parameters considered, a flow regime map is developed to identify the bubble departure type and diameter for a given set of operating conditions. It was noticed that the bubble departure diameter was maximum at low pressure (1 bar), low mass flux (200 kgm−2s−1), high heat flux (500 kWm−2), and low degree of subcooling (20 °C). For all the values of pressure and degree of subcooling, the sliding mode of departure was noticed at low and high mass flux values, whereas bubble departs by lift-off for moderate values of mass flux.
Coarse-grained modeling of zeolitic imidazolate framework-8 using MARTINI force fields
Authors: Alvares Cecilia M. S. , Maurin Guillaume , Semino Rocio
Published: May 2023

In this contribution, the well-known MARTINI particle-based coarse graining approach is tested for its ability to model the ZIF-8 metal-organic framework. Its capability to describe structure, lattice parameters, thermal expansion, elastic constants and amorphization is evaluated. Additionally, the less coarsened models were evaluated for reproducing the swing effect and the host–guest interaction energies were analyzed. We find that MARTINI force fields successfully capture the structure of the Metal-Organic Framework (MOF) for different degrees of coarsening, with the exception of the MARTINI 2.0 models for the less coarse mapping. MARTINI 2.0 models predict more accurate values of C11 and C12, while MARTINI 3.0 has a tendency to underestimate them. Among the possibilities tested, the choice of bead flavors within a particular MARTINI version appears to have a less critical impact in the simulated properties of the empty framework. None of the coarse-grained (CG) models investigated were able to capture the amorphization nor the swing effect within the scope of MD simulations. A perspective on the importance of having a proper Lennard-Jones (LJ) parametrization for modeling guest–MOF and MOF–MOF interactions is highlighted.
Comparison of the effect of suction-injection-combination on Rayleigh–Bénard convection in the case of asymmetric boundaries with those of symmetric ones
Authors: Kanchana C. , Siddheshwar P. G. , Pérez L. M. , Laroze D.
Published: May 2023

The effect of suction-injection-combination (SIC) on the linear and weakly nonlinear stability of Rayleigh–Bénard convection is considered in the paper for the cases of symmetric and asymmetric boundary conditions. Using the Maclaurin series with an appropriate number of terms, expression for eigenfunctions is obtained. The linear theory corroborates the results obtained using the chosen eigenfunctions in the limiting case of the no-SIC effect by matching accurately with the exact values concerning the critical Rayleigh number (Rac) and the wave number (αc). It is found that the effect of SIC is to stabilize the system in the case of symmetric boundaries irrespective of SIC being pro-gravity or anti-gravity. However, the effect of SIC is to stabilize/destabilize the system depending on SIC being pro-gravity or anti-gravity in the case of the asymmetric boundaries. We also noted a similar effect in the case of αc wherein a maximum error of order 10−4 was observed. The main novelty of the present work is studying the influence of SIC on the nonlinear dynamics of the considered problem. It is shown that the effect of SIC is to hasten the onset of chaos. Using various indicators (the largest Lyapunov exponent, the time series solution, the amplitude spectrum, and the phase-space plots), the dynamical behavior of the system is analyzed and the influence of SIC on the dynamics is recorded. The change due to the boundary effect and the SIC on the size of convection rolls and the trapping region where the dynamical system evolves within a bound is highlighted in the paper.
Influence of molecular anisotropy and quadrupolar moment on evaporation
Authors: Homes Simon , Heinen Matthias , Vrabec Jadran
Published: May 2023

The molecular interactions of numerous real fluids, like argon, nitrogen, or carbon dioxide, are adequately described by the two-center Lennard-Jones plus quadrupole potential. Applying this model class in molecular dynamics simulations, evaporation is investigated systematically. The influence of the molecular anisotropy and quadrupole as well as the boundary conditions, i.e., bulk liquid temperature and evaporation magnitude, is reported. A method for specifying the evaporation magnitude in terms of hydrodynamic velocity is further developed for that purpose. Analyses show that the largest molar flux and energy flux occur for spherical molecules and that anisotropy and quadrupole influence several quantities. Depending on the bulk liquid temperature, the quadrupole predominantly affects the interface temperature, while the anisotropy of the molecule significantly influences the interface temperature as well as both molar and energy fluxes. In addition, the preferred average orientation of the molecules in the interface region is investigated. The evaporation coefficient is determined, and thermodynamic states traversed during the evaporation process are discussed.
Operation-induced degradation mechanisms of 275-nm-band AlGaN-based deep-ultraviolet light-emitting diodes fabricated on a sapphire substrate
Authors: Chichibu S. F. , Nagata K. , Oya M. , Kasuya T. , Okuno K. , Ishiguro H. , Saito Y. , Takeuchi T. , Shima K.
Published: May 2023

Degradation mechanisms of 275-nm-band AlxGa1-xN multiple quantum well deep-ultraviolet light-emitting diodes fabricated on a (0001) sapphire substrate were investigated under hard operation conditions with the current of 350 mA and the junction temperature of 105 °C. The optical output power (Po) initially decreased by about 20% within the operating time less than 102 h and then gradually decreased to about 60% by 484 h. For elucidating the causes for the initial and subsequent degradations, complementary electrical, time-resolved photoluminescence (TRPL), and impurity characterizations were carried out making a connection with the energy band profiles. Because the degradation of the wells was less significant than the Po reduction, the initial degradation is attributed essentially to the decrease in carrier injection efficiency (ηinjection), not in internal quantum efficiency of the wells, most likely due to depassivation of initially H-passivated preexisting nonradiative recombination centers (NRCs) in a Mg-doped p-type Al0.85Ga0.15N electron blocking layer. The principal cause for the subsequent Po reduction until 484 h is attributed to further decrease in ηinjection due to the appearance of certain current bypasses in addition to continuous depassivation of the NRCs in p-type AlxGa1-xN layers. According to our database on the species of vacancy-type defects acting as NRCs in GaN and AlN, which have been identified using the combination of positron annihilation and TRPL measurements, vacancy clusters comprised of a cation vacancy (VIII) and nitrogen vacancies (VN), such as VIIIVN2∼4, are the most suspicious origins of the NRCs in Mg-doped p-type AlxGa1-xN layers.
Efficacy analysis of balloon hemostasis technologies in parturient with placenta previa: A hemodynamic numerical and clinical retrospective study
Authors: Li Zhongyou , Luo Rongguang , Jiang Wentao , Liu Chuan , Wang Rui , Yan Fei , Liu Lingjun , Chen Yu
Published: May 2023

To determine the hemostatic values of internal iliac artery balloon (IIABO) occlusion and abdominal aorta balloon occlusion (AABO), 142 patients with pernicious placenta previa were divided into three groups: control (45), IIABO (40), and AABO (57) groups, respectively. The blood loss, operative duration, time-averaged hemorrhage velocity (TAHV), blood transfusion, time-averaged transfusion velocity (TATV), and hospitalization days of these groups were compared. Angiographies and a circulatory simulation were used to unveil the bleeding mechanisms. Although the AABO group's operative duration and hospitalization days are longer (p < 0.001) than those of the other groups, the AABO group has considerably reduced blood loss (p < 0.05) and TAHV (p < 0.001) than the other groups. No obvious difference in blood transfusion and TATV between these groups can be observed. Angiographies showed that there was a large amount of blood flow in the pelvic cavity during IIABO, but AABO did not. In our modeling, the cumulative blood loss is about 2000 ml without using the balloon, which is the same as that when IIABO is used with collateral pressure of 75 mm Hg. The main source of blood loss is uterine arterioles. However, the blood loss during AABO is about 300 ml, which is mainly from uterine venules. These results suggested that IIABO failed to control bleeding, which may be related to collateral circulation, while AABO has a better prospect and may be more effective if the blood pressure of uterine venules is also isolated. These findings may guide technology selections for obstetricians and the improvement of hemostasis technology.
Effect of ambient pressure on the performance of a gas-centered swirl coaxial injector
Authors: Gao Yuchao , Kang Jinxin , Ying Senming , Huang Kejia , Su Lingyu , Tong Yiheng , Lin Wei
Published: May 2023

In this study, water and air were used as simulated media to investigate the spray characteristics of a gas-centered swirl coaxial (GCSC) injector under different ambient pressures through experimental, simulation, and theoretical approaches. The results showed that for the same liquid mass flow rate, the breakup length of the liquid film decreased with increasing ambient pressure, with the extent of the decrease diminishing as the ambient pressure increased. In addition, it was found that under the same ambient pressure, the larger the liquid mass flow rate, the shorter the liquid film breakup length. Moreover, for any gas–liquid mass flow ratio (GLR), the spray angle increased significantly with ambient pressure, and the liquid film suddenly expanded compared to the no-ambient pressure condition. At the same time, the breakup length of the liquid film increased. As ambient pressure increased, the spray angle increased while the breakup length decreased. When the GLR was small, self-pulsation occurred, which gradually disappeared with increasing ambient pressure. The frequency of self-pulsation decreased with increasing ambient pressure. The periodic self-pulsation of the spray was the result of the combined effects of the centrifugal force of the rotating liquid film, surface tension of the liquid film, aerodynamic force, and pressure difference inside and outside the liquid film. Overall, these findings provide insight into the spray characteristics of GCSC injectors under different ambient pressures, which can be of importance to the design and optimization of liquid rocket engines.
Weak trimer distortion and planar spin configuration in hexagonal Lu0.6In0.4FeO3
Authors: Cho Kwanghee , Kamiyama Takashi , Horibe Yoichi , Park Soonyong
Published: May 2023

Improper ferroelectricity and canted ferromagnetism in antiferromagnetically ordered hexagonal ferrites with A2-type spin configuration have been intensely studied due to their potential for room-temperature multiferroicity with strong magnetoelectric couplings. However, the subtle interplay between the magnetic structure and trimer structural distortion, which is a critical ingredient for ferroelectricity, has not been clearly verified in experiments due to the lack of control over trimer distortion. In this study, we report on Lu0.6In0.4FeO3, which exhibits weaker trimer distortion primarily related to the smaller tilting of the FeO5 bipyramids. The reduced vertical displacement of the equatorial oxygen of FeO5 located at the center of the trimer lowers the magnitude of the in-plane Dzyaloshinskii–Moriya vector component, resulting in the absence of canted ferromagnetism with the planar A1-type spin configuration, rather than the canted A2-type observed in other hexagonal ferrites. Our findings demonstrate that the degree of trimer distortion plays an important role in determining the spin configuration in related hexagonal systems.
A comprehensive review of emission reduction technologies for marine transportation
Authors: Huang Jianxun , Duan Xili
Published: May 2023

The marine environment is experiencing significant impacts due to increased shipping traffic. The maritime industry must develop a low-carbon shipping strategy to comply with the increasingly strict emission regulations. This paper comprehensively reviews various decarbonization technologies, including navigation systems, hull design configuration, propulsion and power systems, and alternative fuels. By comparing a wide range of technologies in terms of their emission reduction potential and economic feasibility, this paper is intended to provide a full picture of alternative methods for future green shipping. Alternative fuels and hybrid power systems are found to have high potential for reducing carbon emissions and enhancing sustainability. The type of ship, its design configurations, and operation parameters affect the performance of optimal weather routing systems. With the current maritime policy and technological development, the transition from traditional marine fuel to liquefied natural gas can act as a temporary solution and provide significant decarbonization for maritime transportation. The emission reduction potential can be further enhanced with alternative fuels combined with hybrid power systems with high control flexibility.
Dynamics of the Cl− + CH3I reaction on a high-level ab initio analytical potential energy surface
Authors: Nacsa András B. , Tajti Viktor , Czakó Gábor
Published: May 2023

We have developed a full-dimensional analytical ab initio potential energy surface (PES) for the Cl− + CH3I reaction using the Robosurfer program system. The energy points have been computed using a robust composite method defined as CCSD-F12b + BCCD(T) – BCCD with the aug-cc-pVTZ(-PP) basis set and have been fitted by the permutationally invariant polynomial approach. Quasi-classical trajectory simulations on the new PES reveal that two product channels are open in the collision energy (Ecoll) range of 1–80 kcal/mol, i.e., SN2 leading to I− + CH3Cl and iodine abstraction (above ∼45 kcal/mol) resulting in ICl− + CH3. Scattering angle, initial attack angle, product translational energy, and product internal energy distributions show that the SN2 reaction is indirect at low Ecoll and becomes direct-rebound–back-side (CH3-side) attack-type, as Ecoll increases. Iodine abstraction mainly proceeds with direct stripping mechanism with side-on/back-side attack preference. Comparison with crossed-beam experiments and previous direct dynamics simulations shows quantitative or qualitative agreement and also highlights possible theoretical and/or experimental issues motivating further research.
Interfacial and surface magnetism in epitaxial NiCo2O4(001)/MgAl2O4 films
Authors: Mellinger Corbyn , Wang Xiao , Subedi Arjun , Clark Andy T. , Komesu Takashi , Rosenberg Richard , Dowben Peter A. , Cheng Xuemei , Xu Xiaoshan
Published: May 2023

NiCo2O4 (NCO) films grown on MgAl2O4 (001) substrates have been studied using magnetometry and x-ray magnetic circular dichroism based on x-ray absorption spectroscopy and spin-polarized inverse photoemission spectroscopy with various thicknesses down to 1.6 nm. The magnetic behavior can be understood in terms of a layer of optimal NCO and an interfacial layer (1.2 ± 0.1 nm), with a small canting of magnetization at the surface. The thickness dependence of the optimal layer can be described by the finite-scaling theory with a critical exponent consistent with the high perpendicular magnetic anisotropy. The interfacial layer couples antiferromagnetically to the optimal layer, generating exchange-spring styled magnetic hysteresis in the thinnest films. The non-optimal and measurement-speed-dependent magnetic properties of the interfacial layer suggest substantial interfacial diffusion.
Acoustic surveys improve landscape-scale detection of a critically endangered Australian bird, the plains-wanderer (Pedionomus torquatus)
Authors: Rowe Karen M. C. , Selwood Katherine E. , Bryant David , Baker-Gabb David
Published: May 2023

Context Monitoring the population dynamics of threatened species requires a landscape-scale understanding of their distribution over time. However, detectability is inherently low for rare, widely dispersed, and cryptic species. For animals that vocalise, passive acoustic recorders allow for efficient and repeated surveys over a large geographic area, increasing inference in relation to detectability and occupancy. Aims Our aim was to determine how well acoustic surveys, combined with automated species detection, identified the presence of the critically endangered plains-wanderer (Pedionomus torquatus) relative to a traditional method of nocturnal spotlighting surveys at sites across the Northern Plains of Victoria, Australia. Methods Using Hidden Markov Models, we created 17 different plains-wanderer call recognisers by varying input parameters and assessed their performance on the same training and testing audio dataset. We then applied our best-performing recogniser to a field audio dataset to estimate detectability and compared the presence of plains-wanderers at sites paired with nocturnal surveys. Key results Recognisers varied in their overall performance in detecting individual plains-wanderer calls but were equally effective at determining whether any plains-wanderer calls were detected at a site within our training and testing datasets. Although survey effort was not standardised across field survey methods, we found audio surveys and nocturnal spotlight surveys were equally successful at establishing site-level occupancy; however, acoustic surveys provide the potential to survey more sites over a given time period. Conclusions We suggest acoustic surveys can be an effective and efficient means to document occupancy at the landscape scale, facilitating prioritisation of nocturnal surveys to assess population demographic parameters including abundance and breeding status. Implications Acoustic surveys can provide a complementary method to establish occupancy for cryptic, vocally active, threatened species. We provide recommendations on ways to develop an effective acoustic monitoring program workflow, from data collection to acoustic analysis, that can be used by different user groups.
One Health concept: Viewed by Chinese traditional philosophy from a millennial history
Authors: Yang Guo-Jing , Zhou Xiao-Nong
Published: May 2023

“One Health” has increasingly been accepted as a contemporary theoretical framework to target complex health issues. Historical documents and original records from China’s history can provide important perspectives on how Chinese traditional philosophy dealt with the harmonious relationship between humans, animals, plants, and the environment in the millennial years of civilization. In this commentary, we also presented the active engagements of Chinese scholars in promoting “One Health” and “One Health Action” in China to build a community with a shared future for mankind.

One Health Impact Statement

One Health Impact StatementHistorical documents and original records from China’s history can help us learn how Chinese traditional philosophy has dealt with the harmonious relationship between human, animal, plants and the environment in the thousands of years of civilization. In this commentary, we make an in-depth elaboration on the Chinese meaning of the concept of “One Health” which has been translated into “全健康” in Chinese, meaning as holistic health, based on the history and culture in China, so as to promote “One Health” to play a greater role in building a “community with a shared future for mankind”. China should take a global perspective, pivoting on the “Healthy China” strategy, based on the three interaction fields of “human, animal and environment”, and continuously improve the capabilities in the fields of public health and “One Health” to face the emerging challenge.
Development of WE43/TiC surface composites using friction stir processing: A parametric study
Authors: Kang Amardeep Singh , Singh Ravinder Pal , Singla Shivali
Published: May 2023

Surface composites of WE43 Mg alloy reinforced with TiC nanoparticles were successfully fabricated using friction stir processing. The effects of various tool profiles, tool rotation, and transverse speeds on the metallurgical and mechanical properties of as-received and WE43/TiC composites were comprehensively investigated. The dispersion of TiC nanoparticles was uniform throughout the stir zone. The square tool at 1700 rev min−1 rotational speed and 60 mm min−1 transverse speed produced the finest grain structure in the composites, exhibiting maximum microhardness (151.7 Hv), maximum nano-hardness (1.596 GPa), maximum elastic moduli (36.54 GPa), and minimum wear rate (0.0279 mm3 min−1). Conversely, a square tool at 800 rev min−1 and 60 mm min−1 transverse speed produced the best mechanical properties in the WE43 alloy.
Microstructural and crystallographic characteristics of martensite micro-variants in NiMnGa-based ferromagnetic alloy
Authors: Tong Wei , Liang Li , Wang Huijuan
Published: May 2023

A systematic investigation on microstructural and crystallographic characteristics of martensite micro-variants in Ni54Mn25Ga20.9Dy0.1 ferromagnetic shape memory alloy was performed. The alloys exhibited a dual-phase microstructure consisting of self-accommodated tetragonal martensite and hexagonal Dy-rich dispersive precipitates. In each colony, four distinct micro-variants with different crystallographic-orientations existed, where the adjacent variant pairs connected by crossing-interfaces possessed a non-twinned relationship and other pairs connected by extending-interfaces were twin-related to each other. The corresponding twinning planes and directions were {112} and 〈111〉, respectively. Nevertheless, the twinning relationships of these twin-related micro-variant pairs were not perfect, which contained a small rotation. Interface analysis demonstrated that these two types of interface planes coincide with the orientation relationship planes and twinning planes of their connecting micro-variants, respectively.
Two-body bound and edge bound states in a ladder lattice with synthetic flux
Authors: Zheng Yi , Yang Shi-Jie
Published: May 2023

We study the composite nature of two interacting bosons in the presence of a uniform synthetic flux on a two-leg ladder. We identify the existence of in-cell two-body bound states and nearest-neighbor bound pairs. Under open boundary condition, edge states associated to the bound spectra arise even for the chiral ladder that is topological trivial. We present effective models to characterize the appearance of bound states, as well as to capture the localization and chiral properties of the edge bound state (EBS). Moreover, we incorporate the diagonal coupling into the ladder, constituting a Creutz model which supports topological phase transition. We show that the interplay of non-trivial band topology and the two-body interaction leads to topological EBS that is robust against local potential defect.
Mesoscopic modeling of field evaporation on atom probe tomography
Authors: Hatzoglou Constantinos , Klaes Benjamin , Delaroche Fabien , Costa Gérald Da , Geiser Brian , Kühbach Markus , Wells Peter B , Vurpillot François
Published: May 2023

Reconstructions in atom probe tomography (APT) are biased by image distortions arising from dynamic changes of the specimen geometry that controls image projection. Despite the strong efforts to build realistic models for understanding and reproducing image artifacts, the current models are too slow or not adapted to be routinely used in image correction approaches. To understand the APT imaging process for real size samples submitted to realistic experimental conditions of electric field and temperature, we propose an alternative simulation tool based on a coarse-grained model of the sample surface. The surface electric field on a meshed surface is calculated by using continuous models describing field evaporation. The dynamic evolution of the sample surface and the image projection are predicted using materials properties. We show that the interplay between temperature and electric field is an important ingredient in predicting the ion projection, in pure metals and in more complex materials. This fast approach accurately reproduces the well-known local magnification and trajectory overlaps effects in the evaporation of small particles. By combining prior knowledge about the sample structure and properties, the model could be used to improve the reconstruction approaches for complex sample geometries.
A highly sensitive capacitive flexible tactile sensor based on a composite dielectric layer with a C-type symmetrical structure for wearable electronics
Authors: Zhu Tong , Yan Zihao , Su Leqiang , Ye Bin , Yao Xiaomeng , Song Yuerong , Wang Ming , Jiao Ziyang , Zhang Xinyi , Li Jiming , Cao Yuxin , Hua Liangping , Pan Juncong
Published: May 2023

In this work, a capacitive flexible tactile sensor based on the composite dielectric layer with a C-type symmetrical structure is proposed to improve the sensing performance through the introduction of a precise structure. Combined with simulations and experiments, the influence of the structural characteristics of the tactile sensor on its sensitivity is investigated, the correlation between the signal output of the sensor and the loading pressure is shown for different structural parameter designs, and the structure of the sensor is optimized. Data results display that the tactile sensor proposed in this work exhibits a lower detection limit (8.6 Pa) and an ultra-wide linear sensing range (8.6–500 kPa). In addition, from the 55 ms response time of the sensor and 2000 cycles of experiments, it can be concluded that the sensor possesses good repeatability and durability, and can achieve more accurate measurement results in motion detection, soft robots, and electronic skin.
Two-dimensional g-GeC/PtSe2 van der Waals heterostructure: a visible light-driven direct Z-scheme photocatalyst for overall water splitting
Authors: Xu Y H , Han J N , Li Z H , Zhang Z H
Published: May 2023

The vertical stacking of different two-dimensional materials to construct van der Waals heterostructures (vdWHs) opens up a promising platform for designing high-efficiency photocatalysts. Direct Z-scheme heterostructures for photocatalytic dissociation have received much attention in recent years, in which charge carriers migrate directly between two semiconductors without redox mediators. Here, the electronic and optical properties as well as the solar-to-hydrogen conversion efficiency of g-GeC/ PtSe2 vdWHs are systematically investigated, especially for their high-efficiency visible-light water splitting catalyst features. Calculations show that the g-GeC/ PtSe2 vdWH is a semiconductor with an indirect band gap of 1.356 eV, featuring a type-II band alignment. The built-in electric field E
int and band bending at the interface lead to a direct Z-scheme photocatalytic structure, and photocatalytic water splitting can be realized in the pH range of 0–14. In particular, with biaxial tensile strain ϵ= 4% applied, the g-GeC/PtSe2 vdWH possesses a smaller band gap, wider visible light response range and very high STH conversion efficiency (η
STH) up to 49.07%, entirely satisfying the optimal photocatalytic water splitting conditions. This work provides a new perspective for designing promising direct Z-scheme visible light water splitting catalysts with a high-efficiency solar energy conversion, beneficially to the development of clean energy.
Low-energy hole subband dispersions in a cylindrical Ge nanowire: the effects of the nanowire growth direction
Authors: Li (李睿) Rui , Li (李子强) Zi-Qiang
Published: May 2023

We examine the validity of the spherical approximation

γ

s

=
(
2

γ

2

+
3

γ

3

)

/

5

in the Luttinger–Kohn Hamiltonian in calculating the subband dispersions of the hole gas. We calculate the realistic hole subband dispersions (without the spherical approximation) in a cylindrical Ge nanowire by using quasi-degenerate perturbation theory. The realistic low-energy hole subband dispersions have a double-well anticrossing structure, that consists with the spherical approximation prediction. However, the realistic subband dispersions are also nanowire growth direction dependent. When the nanowire growth direction is restricted in the (100) crystal plane, the detailed growth direction dependences of the subband parameters are given. We find the spherical approximation is good approximation, it can nicely reproduce the real result in some special growth directions.
Absorbed dose coefficients for adult thyroid cancer patients undergoing radioiodine therapy
Authors: Kwon Tae-Eun , Pasqual Elisa , Kitahara Cari M , Lee Choonsik
Published: May 2023

Use of radioactive iodine (RAI) for thyroid cancer patients is accompanied by elevated risks of radiation-induced adverse effects due to significant radiation exposure of normal tissues or organs other than the thyroid. The health risk estimation for thyroid cancer patients should thus be preceded by estimating normal tissue doses. Although organ dose estimation for a large cohort often relies on absorbed dose coefficients (i.e. absorbed dose per unit activity administered, mGy MBq−1) based on population models, no data are available for thyroid cancer patients. In the current study, we calculated absorbed dose coefficients specific for adult thyroid cancer patients undergoing RAI treatment after recombinant human TSH (rhTSH) administration or thyroid hormone withdrawal (THW). We first adjusted the transfer rates in the biokinetic model previously developed for THW patients for use in rhTSH patients. We then implemented the biokinetic models for thyroid cancer patients coupled with S values from the International Commission on Radiological Protection (ICRP) reference voxel phantoms to calculate absorbed dose coefficients. The biokinetic model for rhTSH patients predicted the extrathyroidal iodine decreasing noticeably faster than in the model for THW patients (calculated half-times of 12 and 15 h for rhTSH administration and THW, respectively). All dose coefficients for rhTSH patients were lower than those for THW patients with the ratio (rhTSH administration/THW) ranging from 0.60 to 0.95 (mean = 0.67). The ratio of the absorbed dose coefficients in the current study to the ICRP dose coefficients, which were derived from models for normal subjects, varied widely from 0.21 to 7.19, stressing the importance of using the dose coefficients for thyroid cancer patients. The results of this study will provide medical physicists and dosimetrists with scientific evidence to protect patients from excess exposure or to assess radiation-induced health risks caused by RAI treatment.
Time-of-flight anemometry using a displacement plate-beamsplitter
Authors: Bollt Scott A
Published: May 2023

We propose the use of a second surface mirror as a displacement plate-beamsplitter to provide significant simplification and cost reduction of time-of-flight anemometry (ToFA), without sacrificing precision and accuracy. These benefits are most pronounced for long-range applications. Our method’s principle benefits are due to the few and simple components it requires as well as low sensitivity to both temperature effects and light source incoherence. We found that precise and accurate results are possible using a common consumer mirror as the main optical element and an inexpensive diode laser as the light source, which could broaden access to laser anemometry and make many industry applications economically feasible. The nature of the design also permits an increase in range for a given laser power since the method can utilize the entire optical area of the focusing lens/mirror independent of other design considerations and the cost of a flat second-surface mirror is usually negligible. To characterize the performance of this method, we develop a Cramer–Rao bound (CRB) for a general class of ToFA’s with multiple Gaussian beams under signal-independent Gaussian white noise. For a given measurement volume, the lowest velocity uncertainty is achieved by creating a standard two-sheet geometry: power-matching the first two beams by adjusting the beamsplitter and blocking the rest of the beams is optimal. However, keeping the higher order beams permits determination of flow direction. Conditions to achieve beam power-matching are given. An anemometer is built using a diode laser with 12 mw 405 nm beam using a total of just three transmitting optical components. Our setup has an accuracy of 99.1%. The worst-case precision of 96.7% nearly achieves the CRB, although optimizing the setup more can lower the bound, and therefore allow increase in the performance by an order of magnitude or more.
Joint ergodicity of piecewise monotone interval maps
Authors: Bergelson Vitaly , Son Younghwan
Published: May 2023

For

i
=
0
,
1
,
2
,
…
,
k

, let µ

i
be a Borel probability measure on

[
0
,
1
]

which is equivalent to the Lebesgue measure λ and let

T
i

:
[
0
,
1
]
→
[
0
,
1
]

be µ

i
-preserving ergodic transformations. We say that transformations

T
0

,

T
1

,
…
,

T
k

are uniformly jointly ergodic with respect to

(
λ
;

μ
0

,

μ
1

,
…
,

μ
k

)

if for any

f
0

,

f
1

,
…
,

f
k

∈

L

∞

,

lim

N
−
M
→
∞

1

N
−
M

∑

n
=
M

N
−
1

f
0

(

T
0

 
n

x
)
⋅

f
1

(

T
1

 
n

x
)
⋯

f
k

(

T
k

 
n

x
)
=

∏

i
=
0

k

∫

f
i

d

μ
i

 
in 

L
2

(
λ
)
.

We establish convenient criteria for uniform joint ergodicity and obtain numerous applications, most of which deal with interval maps. Here is a description of one such application. Let T

G
denote the Gauss map,

T
G

(
x
)
=

1
x

(

m
o
d

1
)

, and, for β > 1, let T

β
denote the β-transformation defined by

T

β

x
=
β
x
(

m
o
d

1
)

. Let T
0 be an ergodic interval exchange transformation. Let

β
1

,
…
,

β
k

be distinct real numbers with

β
i

>
1

and assume that

log

β
i

≠

π
2

6
log
2

for all

i
=
1
,
2
,
…
,
k

. Then for any

f

0

,

f
1

,

f

2

,
…
,

f

k
+
1

∈

L

∞

(
λ
)

,

lim

N
−
M
→
∞

1

N
−
M

∑

n
=
M

N
−
1

f

0

(

T
0

n

x
)
⋅

f

1

(

T

β
1

n

x
)
⋯

f

k

(

T

β
k

n

x
)
⋅

f

k
+
1

(

T
G

n

x
)

=
∫

f

0

d
λ
⋅

∏

i
=
1

k

∫

f

i

d

μ

β
i

⋅
∫

f

k
+
1

d

μ
G

in 

L

2

(
λ
)
.

We also study the phenomenon of joint mixing. Among other things we establish joint mixing for skew tent maps and for restrictions of finite Blaschke products to the unit circle.
Spatial–temporal features-based EEG emotion recognition using graph convolution network and long short-term memory
Authors: Zheng Fa , Hu Bin , Zheng Xiangwei , Zhang Yuang
Published: May 2023

Objective. Emotion recognition on the basis of electroencephalography (EEG) signals has received a significant amount of attention in the areas of cognitive science and human–computer interaction (HCI). However, most existing studies either focus on one-dimensional EEG data, ignoring the relationship between channels, or only extract time–frequency features while not involving spatial features. Approach. We develop spatial–temporal features-based EEG emotion recognition using a graph convolution network (GCN) and long short-term memory (LSTM), named ERGL. First, the one-dimensional EEG vector is converted into a two-dimensional mesh matrix, so that the matrix configuration corresponds to the distribution of brain regions at EEG electrode locations, thus to represent the spatial correlation between multiple adjacent channels in a better way. Second, the GCN and LSTM are employed together to extract spatial–temporal features; the GCN is used to extract spatial features, while LSTM units are applied to extract temporal features. Finally, a softmax layer is applied to emotion classification. Main results. Extensive experiments are conducted on the A Dataset for Emotion Analysis using Physiological Signals (DEAP) and the SJTU Emotion EEG Dataset (SEED). The classification results of accuracy, precision, and F-score for valence and arousal dimensions on DEAP achieved 90.67% and 90.33%, 92.38% and 91.72%, and 91.34% and 90.86%, respectively. The accuracy, precision, and F-score of positive, neutral, and negative classifications reached 94.92%, 95.34%, and 94.17%, respectively, on the SEED dataset. Significance. The above results demonstrate that the proposed ERGL method is encouraging in comparison to state-of-the-art recognition research.
Generation of tunable terahertz radiation by a laser pulse propagating in a magnetized plasma channel
Authors: Singh Saumya , Mishra Dinkar , Kumar Bhupesh , Jha Pallavi
Published: May 2023

A study of the generation of terahertz (THz) radiation by propagation of a circularly polarized laser pulse in a parabolic plasma channel is presented. The laser–plasma system is embedded in a uniform axial magnetic field. Transverse electric and magnetic wakefields are evaluated using a perturbation scheme and quasi-static approximation. Nonlinear plasma electron velocities arise along the longitudinal and transverse directions as a result of interaction with the laser pulse. This results in the generation of an electromagnetic wave oscillating at THz frequency. The frequency of the obtained THz radiation can be controlled using the plasma channel parameters and can be tuned by varying the transverse position of observation. The THz radiation amplitude is enhanced in the presence of the parabolic channel compared to the homogeneous plasma configuration. The possibility of obtaining a tunable range of THz frequencies is presented. The analytical results have been validated using three-dimensional particle-in-cell simulations.
Dynamic responses of an energy harvesting system based on piezoelectric and electromagnetic mechanisms under colored noise
Authors: Yang Yong-Ge , Meng Yun , Zeng Yuan-Hui , Sun Ya-Hui
Published: May 2023

Because of the increasing demand for electrical energy, vibration energy harvesters (VEHs) that convert vibratory energy into electrical energy are a promising technology. In order to improve the efficiency of harvesting energy from environmental vibration, here we investigate a hybrid VEH. Unlike previous studies, this article analyzes the stochastic responses of the hybrid piezoelectric and electromagnetic energy harvesting system with viscoelastic material under narrow-band (colored) noise. Firstly, a mass-spring-damping system model coupled with piezoelectric and electromagnetic circuits under fundamental acceleration excitation is established, and analytical solutions to the dimensionless equations are derived. Then, the formula of the amplitude-frequency responses in the deterministic case and the first-order and second-order steady-state moments of the amplitude in the stochastic case are obtained by using the multi-scales method. The amplitude-frequency analytical solutions are in good agreement with the numerical solutions obtained by the Monte Carlo method. Furthermore, the stochastic bifurcation diagram is plotted for the first-order steady-state moment of the amplitude with respect to the detuning frequency and viscoelastic parameter. Eventually, the influence of system parameters on mean-square electric voltage, mean-square electric current and mean output power is discussed. Results show that the electromechanical coupling coefficients, random excitation and viscoelastic parameter have a positive effect on the output power of the system.