bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal transport and optical anisotropy in CVD grown large area few-layer MoS2 over an FTO substrate
Authors: Singh Ankita , Gupta Rohit Kumar , Mishra Ashish Kumar
Published: January 2024

Atomically thin MoS2 is a promising candidate for its integration into devices due to its strikingly unique electronic, optical, and thermal properties. Here, we report the fabrication of a few-layer MoS2 thin film over a conducting fluorine-doped tin oxide-coated glass substrate via a one-step chemical vapor deposition method. We have quantitatively analyzed the nonlinear temperature-dependent Raman shift using a physical model that includes thermal expansion and three- and four-phonon anharmonic effects, which exhibits that the main origin of nonlinearity in both the phonon modes primarily arises from the three-phonon anharmonic process. We have also measured the interfacial thermal conductance (g) and thermal conductivity (ks) of the synthesized film using the optothermal Raman spectroscopy technique. The obtained values of g and ks are ∼7.218 ± 0.023 MW m−2 K−1 and ∼40 ± 2 W m−1 K−1, respectively, suggesting the suitability of thermal dissipation in MoS2 based electronic and optoelectronic devices. Furthermore, we performed a polarization study using the angle resolved polarized Raman spectroscopy technique under non-resonance and resonance excitations to reveal the electron–photon–phonon interaction in the prepared MoS2, based on the semi-classical theory that includes deformation potential and Fröhlich interaction. Our study provides much needed experimental information about thermal conductivity and polarization response in a few-layer MoS2 grown over the conducting substrate, which is relevant for applications in low power thermoelectric and optoelectronic devices.
Domain structures of PbTiO3 and Pb(Zr,Ti)O3 thin films controlled by tensile strain induced by a Sr(Zr,Ti)O3 buffer layer
Authors: Morikawa Tomohide , Kodera Masanori , Shimizu Takao , Ishihama Keisuke , Ehara Yoshitaka , Sakata Osami , Funakubo Hiroshi
Published: January 2024

Thin films of Sr(Zr,Ti)O3 were investigated as buffer layers to induce tensile strain in ferroelectric thin films such as PbTiO3 and Pb(Zr,Ti)O3 to control the domain structure. By tuning the composition of Sr(Zr,Ti)O3, (100)-oriented PbTiO3 and Pb(Zr,Ti)O3 films were obtained, revealing that tensile strain was introduced into the thin films by the lattice of the buffer layer. We propose a methodology for the successive control of tensile stress, which is useful for understanding and controlling the domain structures of ferroelectric films that result in the ferroelectric and piezoelectric properties of ferroelectric thin films.
Topological polarization singular enables multiple-system excellent circular dichroism via chiral bound states in the continuum with all-dielectric metasurfaces
Authors: Zong Shu , Chen Jiafei , Cai Shijie , Liu Xiaoshan , Liu Guiqiang , Chen Jing , Tang Chaojun , Du Wei , Liu Zhengqi
Published: January 2024

The advancements in chiroptics have propelled applications beyond traditional optics, expanding its reach into domains such as heat and fluid mechanics. The current research predominantly focused on utilizing plasmonic materials in the photothermal and photofluidic systems. However, these systems face limitations in circular dichroism due to inherent Ohmic loss associated with plasmonic materials. Herein, we introduce the concept of topological polarization singularity in an all-dielectric structure, which supports chiral bound states in the continuum. The introduction of topological polarization singularity gives the structure an impressive chiral light absorption response. The BICs resonant mode achieves a 147-fold field enhancement, significantly improving the photothermal conversion efficiency of dielectric material. Moreover, the g factors of photothermal and optical fluids reach 1.9, approaching the theoretical limit value. Consequently, an exceptionally high degree of circular dichroism is realized in multiple systems including light absorption, photothermal, and photofluidic systems. Our proposed structures can potentially be used in chiral photothermal and chiral nanoparticle capture, as well as photofluidic applications related to biochemistry and clinical biology.
Investigating the dissipation of heat and quantum information from DNA-scaffolded chromophore networks
Authors: Rolczynski Brian S. , Díaz Sebastián A. , Goldman Ellen R. , Medintz Igor L. , Melinger Joseph S.
Published: January 2024

Scaffolded molecular networks are important building blocks in biological pigment–protein complexes, and DNA nanotechnology allows analogous systems to be designed and synthesized. System–environment interactions in these systems are responsible for important processes, such as the dissipation of heat and quantum information. This study investigates the role of nanoscale molecular parameters in tuning these vibronic system–environment dynamics. Here, genetic algorithm methods are used to obtain nanoscale parameters for a DNA-scaffolded chromophore network based on comparisons between its calculated and measured optical spectra. These parameters include the positions, orientations, and energy level characteristics within the network. This information is then used to compute the dynamics, including the vibronic population dynamics and system–environment heat currents, using the hierarchical equations of motion. The dissipation of quantum information is identified by the system’s transient change in entropy, which is proportional to the heat currents according to the second law of thermodynamics. These results indicate that the dissipation of quantum information is highly dependent on the particular nanoscale characteristics of the molecular network, which is a necessary first step before gleaning the systematic optimization rules. Subsequently, the I-concurrence dynamics are calculated to understand the evolution of the vibronic system’s quantum entanglement, which are found to be long-lived compared to these system–bath dissipation processes.
Sub-bandgap optical absorption processes in 300-nm-thick Al1−xInxN alloys grown on a c-plane GaN/sapphire template
Authors: Imai Daichi , Murakami Yuto , Toyoda Hayata , Noda Kouki , Masaki Kyosuke , Kubo Kazutoshi , Nomura Mayu , Miyoshi Makoto , Miyajima Takao , Takeuchi Tetsuya
Published: January 2024

We investigate the sub-bandgap optical absorption (SOA) in 300-nm-thick Al1−xInxN alloys used in cladding layers of edge-emitting laser diodes and distributed Bragg reflectors of vertical-cavity surface-emitting lasers. Al1−xInxN alloys, with indium content x ranging from 0.114 to 0.185, were grown by metal-organic chemical vapor deposition on a c-plane GaN/sapphire template. SOAs on 300-nm-thick thin films were characterized using photothermal deflection spectroscopy (PDS). Thermal emission, such as nonradiative recombination with phonon emission, is the dominant energy relaxation process occurring after SOA in Al1−xInxN alloys. The absorption coefficient of the SOA was estimated to be 0.6–7.0 × 103 cm−1 in these samples by combining PDS and spectroscopic ellipsometry. The drastic increase in the SOA, when x exceeded the lattice-matched composition of the GaN/sapphire template, indicates that impurities, vacancy-type defects, and their complexes with increasing x are possible candidates that result in SOA in Al1−xInxN alloys.
The interface instability development induced by the bulk density perturbations in accelerated media
Authors: Gorodnichev K. E. , Zakharov P. P. , Glazyrin S. I. , Kuratov S. E.
Published: January 2024

The development of hydrodynamic instabilities has a significant impact on the operation of laser fusion systems. During radiation compression, the shells of a target are accelerated, resulting in the growth of perturbations at their interfaces. In this paper, we study the influence of density perturbations on the stability of the contact boundary during accelerated motion. The analysis is performed in a two-dimensional planar formulation using the linear approximation and assuming a weak spatial dependence on the temperature near the contact boundary. Due to the consideration of small time intervals, the phenomenon of heat conduction is not taken into account. The cases of acceleration of a medium described by the Mie–Grüneisen equation of state (EoS) into a vacuum and of acceleration of two contacting media, each described by the ideal plasma EoS, are considered. The time dependence of the amplitude of the boundary perturbation on time is obtained. The obtained values are in agreement with the results of numerical analysis. It is shown that the boundary curvature occurs independently of the acceleration direction. The theoretical results are compared with numerical results for laser fusion systems.
Effects of multi motion responses and incident-wave height on the gap resonances in a moonpool
Authors: Jing Penglin , Cui Ting , He Guanghua , Zhang Cheng , Luan Zhengxiao
Published: January 2024

The hydrodynamic characteristics of a free-floating moonpool encountering the gap resonances are investigated based on the constrained interpolation profile method in numerical wave tank. This paper mainly concentrates on the influences of the moonpool's motion responses and the incident-wave height on the gap resonances in the free-floating moonpool. Numerical results demonstrated that the heave response significantly changes the frequency and the magnitude of the linear gap resonance, while the roll motion influences more on the vertical wave loads and the wave responses in the fluid field. The heave and roll response of the free-floating moonpool are generally independent. Moreover, the magnitudes of the nonlinear gap resonances have the tendency of catching up and exceeding the linear gap resonance as the incident-wave height increasing for the free-floating moonpool, which is the consequence of the higher-order harmonics driven by the nonlinear processes and the linear secondary resonant region induced by the heave response. Based on the wavelet transform, it could be observed that the amplified harmonic component usually takes more time to be fully developed than other harmonic components during the development of its corresponding nonlinear gap resonance.
Pore-scale imbibition patterns in layered porous media with fractures
Authors: Li Bo , Yu Hao , Ji DongQi , Wang FengChao , Lei ZhengDong , Wu HengAn
Published: January 2024

The presence of fractures increases the difficulty of flow mechanisms analysis, and it remains unclear how fractures affect multiphase flow displacement in the layered rock matrix. Herein, a pore-scale imbibition model considering the layered matrix-fracture system is established using the phase-field method, where oil is displaced by a range of fluids with various properties. Two typical flow modes are carefully analyzed, depending on the locations of the fracture and the interfaces between different layers of the matrix: fracture is parallel to the interface (mode I), and it penetrates through the interface (mode II), which are dominated by the co-current imbibition and countercurrent imbibition mechanisms, respectively. Interestingly, the surface tension is found to be negatively correlated with the ultimate oil recovery rate for mode I and plays an opposite effect on that of mode II. For flow mode I, the conditions of lower injection rate, higher viscosity ratio, higher grain diameter ratio, and injection of the invading fluid from the larger pore throat size (positive direction flow) can improve oil recovery. For flow mode II, the fracture bifurcation angle has little effect on the positive direction flow, while it can significantly regulate the phase distribution in the negative direction flow. Based on scaling analysis of relating pore-filling events to displacement modes and the equilibrium relationship between capillary and viscous forces, two theoretical models are derived to predict the imbibition patterns, and the variation of the flow regime under various parameters in the typical layered matrix-fracture models is systematically concluded.
Multiple data streams over a single optical path
Authors: Fu Kang , Fu Jianwei , Wang Binju , Yan Jiabin , Liu Pengzhan , Ji Xiangyang , Zhu Hongbo , Wang Yongjin
Published: January 2024

Quantum well (QW) diodes have the capability to function as a light-emitting diode or a photodiode and inherently feature a partial emission-detection spectral overlap. Therefore, QW diode can sense light emission from another diode sharing the same QW active region. In association with distributed Bragg reflection (DBR) technique, we here present a wavelength-division multiplexing (WDM) visible light communication (VLC) over a single channel by using vertical assembly of red, green, and blue (RGB) QW diodes. The identical QW diodes separately functioning as a transmitter and a receiver establish a wireless communications link. The DBRs enable the transmission of longer-wavelength photons or the reflection of shorter-wavelength photons, creating an optical bandpass filter in conjunction with emission-detection spectral overlap, effectively boosting the capacity of an initially single communication channel. Both the transmitter and the receiver can be switched freely by software, forming time-division multiplexing (TDM) wireless light communication system using single optical path. We unite TDM and WDM together to demonstrate real-time TDM multichannel bidirectional communication using the vertical integration of RGB QW diodes, offering the great potential to establish TDM-WDM VLC.
Fast flow field prediction of three-dimensional hypersonic vehicles using an improved Gaussian process regression algorithm
Authors: Yang Yuxin , Xue Youtao , Zhao Wenwen , Yao Shaobo , Li Chengrui , Wu Changju
Published: January 2024

Conducting large-scale numerical computations to obtain flow field during the hypersonic vehicle engineering design phase can be excessively costly. Although deep learning algorithms enable rapid flow field prediction with high-precision, they require a significant investment in training samples, contradicting the motivation of reducing the cost of acquiring flow field. The combination of feature extraction algorithms and regression algorithms can also achieve high-precision prediction of flow fields, which is more suitable to tackle three-dimensional flow prediction with a small dataset. In this study, we propose a reduced-order model (ROM) for the three-dimensional hypersonic vehicle flow prediction utilizing proper orthogonal decomposition to extract representative features and Gaussian process regression with improved automatic kernel construction (AKC-GPR) to perform a nonlinear mapping of physical features for prediction. The selection of variables is based on sensitivity analysis and modal assurance criterion. The underlying relationship is unveiled between flow field variables and inflow conditions. The ROM exhibits high predictive accuracy, with mean absolute percentage error (MAPE) of total field less than 3.5%, when varying altitudes and Mach numbers. During angle of attack variations, the ROM only effectively reconstructs flow distribution by interpolation with a MAPE of 7.02%. The excellent small-sample fitting capability of our improved AKC-GPR algorithm is demonstrated by comparing with original AKC-GPRs with a maximum reduction in a MAPE of 35.28%. These promising findings suggest that the proposed ROM can serve as an effective approach for rapid and accurate vehicle flow predicting, enabling its application in engineering design analysis.
Droplet pair breakup in microfluidic expansion channel
Authors: Kuang Yihan , Deng Tao , Huang Yingzhou , Liu Liyu , Chen Guo
Published: January 2024

Previous studies on droplet splitting mainly focus on monodisperse droplets, and the understanding of the breakup of polydisperse droplet systems is still lacking. In this work, we experimentally study the breakup of droplet pairs in the expansion region of microfluidic channel. The results show that with the increase in the size ratio of the droplets in the droplet pair, the breakup mode of droplet pairs changes from rear droplet breakup to front droplet breakup, and then to front droplet alternate breakup. The expansion angle can affect the critical size ratio of the splitting mode transition, but it cannot change the transition trend. The expansion angle plays a major role in the splitting time and distance of the droplet pair. When the expansion angle is increased, the splitting time of the droplet pair is reduced and the splitting distance is shorter. Our study extends the understanding of the breakup of non-monodisperse droplet systems and provides a feasible approach for the selective and controllable splitting of droplets, which is important for laboratory-on-a-chip droplet volume manipulation and has potential applications.
Shock electrostatic electron acoustic wave features in four-component electron–positron plasma
Authors: Abdelwahed H. G. , El-Shewy E. K.
Published: January 2024

The linear (nonlinear) wave properties of dissipative electron acoustic plasma have been studied. The impacts of temperatures and densities on the properties of linear real and imaginary (growth rate) plasma frequencies have been examined. The effects of viscosities in the linear growth rate are also studied. Accordingly, the significant shock-like electrostatic field in auroral plasmas has been discussed. Furthermore, the electrostatic dissipative fields have been studied to explain experimental observations. A comparison between the obtained electrostatic dissipative fields and satellite observations in auroral plasmas is briefly discussed.
Lowering the reactor breakeven requirements for proton–boron 11 fusion
Authors: Ochs Ian E. , Fisch Nathaniel J.
Published: January 2024

Recently, it has been shown that altering the natural collisional power flow of the proton–boron 11 (pB11) fusion reaction can significantly reduce the Lawson product of ion density and confinement time required to achieve ignition. However, these products are still onerous—on the order of 7×1015 cm−3 s under the most optimistic scenarios. Fortunately, a breakeven fusion power plant does not require an igniting plasma, but rather a reactor that produces more electrical power than it consumes. Here, we extend the existing 0D power balance analysis to check the conditions on power plant breakeven. We find that even for the base thermonuclear reaction, modern high-efficiency thermal engines should reduce the Lawson product to 1.2×1015 cm−3 s. We then explore the impact of several potential improvements, including fast proton heating, alpha power capture, direct conversion, and efficient heating. We find that such improvements could reduce the required Lawson product by a further order of magnitude, bringing aneutronic fusion to target ITER ion densities and confinement times.
Low-consumption stepper motor controller with real-time target position change responsiveness based on field programmable gate array
Authors: Shi Tong , Guo Zhanshe , Wang Tian , Tan Haishu , Zhou Fuqiang
Published: January 2024

In response to the demand for low resource consumption, parallel control, and real-time response to target position changes in precision measurement and manufacturing of multi-axis stepper motor controllers, this paper proposes a field programmable gate array-based method for generating trapezoidal velocity profiles and pulse generation, which can easily keep parallelism and independence during multi-axis control. By avoiding using multiplication and division, this controller not only reduces resource consumption but also enhances the pulse output frequency. To address the real-time responsiveness of the velocity profile generation algorithm to changes in the target position during the control process, the algorithm introduces a novel real-time comparative state transition logic for speed control, which makes it capable of adjusting the acceleration within a single clock cycle, enabling its application in scenarios that require higher levels of real-time performance. Finally, the designed controller is applied to a four-axis positioning system for performance validation.
Impact of bio-inspired V-formation on flow past arrangements of non-lifting objects
Authors: Suchandra Prasoon , Raayai-Ardakani Shabnam
Published: January 2024

Inspired by the energy-saving character of group motion, great interest is directed toward the design of efficient swarming strategies for groups of unmanned aerial/underwater vehicles. While most of the current research on drone swarms addresses controls, communication, and mission planning, less effort is put toward understanding the physics of the flow around the members of the group. Currently, a large variety of drones and underwater vehicles consist of non-lifting frames for which the available formation flight strategies based on lift-induced upwash are not readily applicable. Here, we explore the V-formations of non-lifting objects and discuss how such a configuration alters the flow field around each member of the array compared to a solo flyer and how these changes in flow physics affect the drag force experienced by each member. Our measurements are made in a water tunnel using a multi-illumination particle image velocimetry technique where we find that in formations with an overlap in streamwise projections of the members, all the members experience a significant reduction in drag, with some members seeing as much as 45% drag reduction. These findings are instrumental in developing generalized energy-saving swarming strategies for aerial and underwater vehicles irrespective of the body shapes.
An assessment of the suitability of a Liebau pump in biomedical applications
Authors: Anatol Joaquín , García-Díaz Manuel , Barrios-Collado César , Moneo-Fernández José A. , Rubio Manuel , Castro-Ruiz Francisco , Sierra-Pallares José
Published: January 2024

Impedance pumping and asymmetric pumping are the main mechanisms of the Liebau effect, a type of valveless pumping. The primary objective of this study is to enhance the current understanding of the mechanics and functionality of a Liebau pump. To achieve this, a prototype pump is constructed, incorporating several novel features: a pinch frequency control system to optimize pump performance, a planar actuator developed using soft robotic technology, and a compliant chamber designed to mitigate flow fluctuations and prevent reverse flow, a common feature of this pumping method. Experimental tests conducted with this prototype demonstrate that the Liebau pump holds potential as a viable technology for fluid pumping in biomedical applications, especially when pulsatile flow is essential or when hemolysis needs to be minimized.
Complex dispersion analysis of true and pseudo surface waves propagating in two-dimensional viscoelastic seismic metamaterials
Authors: Ma Tian-Xue , Cao Leilei
Published: January 2024

In this paper, the wave characteristics of true surface waves (TSWs) and pseudo surface waves (PSWs) in two-dimensional (2D) seismic metamaterials are explored. The 2D seismic metamaterial is formed by placing periodic concrete pillars on the surface of the soil substrate. The complex dispersion curves of the seismic metamaterial are numerically calculated by the ω–kapproach. The Kelvin–Voigt model is adopted to describe the material viscoelasticity. The results show that not only the TSW modes but also the PSW modes should be taken into account to evaluate the mitigation capacity of the seismic metamaterials. Due to the introduction of material viscoelasticity, the TSWs and PSWs convert from the propagative mode to the evanescent mode. When the PSW modes propagate along the substrate surface, their energy gradually leaks into the bulk of the substrate, leading to their transmission coefficient smaller than that of the TSW modes. Compared to the concrete pillars on the substrate surface, the viscoelasticity of the soil substrate plays a more important role in surface wave reduction. Moreover, the wave propagating length in the seismic metamaterials can be predicted by using complex dispersion relations.
Experimental study on spatiotemporal correlation and similarity law of transonic buffeting loads
Authors: Zhao XiaoJian , Zhang LeiGang , Chen Zheng
Published: January 2024

The spatiotemporal correlation of transonic buffet, driven by strong shock waves and boundary-layer separation, plays a critical role in causing structural vibrations in launch vehicles. To investigate this correlation, a wind tunnel experiment was conducted to measure the time-frequency characteristics of wall fluctuation pressures. The phase array approach was employed to obtain the spatial correlation of buffeting load. The results indicate that the low-frequency hydrodynamic modes dominate the separation flow and shock oscillation, while the attached flow is predominantly influenced by broadband acoustic modes. The space-time correlation analysis reveals that the peak buffeting load, for typical flows, results from the convergence of energy beneath the turbulent boundary layer. Furthermore, a similarity law for the spatial correlation of buffeting load was derived and validated by the measurement data. Based on the measured buffeting load data, an improved W–F (Wavenumber–Frequency spectrum) model with scaling spatiotemporal correlation was developed. This model serves as a theoretical foundation for predicting buffeting loads under flight conditions.
A core loss estimation method based on improved waveform coefficient Steinmetz equation for asymmetric triangular flux density waveform
Authors: Li Yongjian , Qin Kangshuo , Mu Shenghui , Yin Jiatong
Published: January 2024

Accurate estimation of high frequency magnetic core losses under non-sinusoidal excitations is critical to the design of solid-state transformers. This paper proposes a waveform transformation principle, termed the equal derivative transformation (EDT), for piecewise linear flux density waveforms. Under the same maximum flux density, an asymmetric triangular flux density wave can be transformed into a symmetric one with a different frequency in terms of the calculation of core losses, hence the introduction of the improved waveform coefficient Steinmetz equation (iWcSE). The magnetic characteristics of three different toroidal samples (nanocrystalline alloy FT-3KL, amorphous alloy 1K101, ferrite N87) under square excitation at different duty ratios and certain frequencies are measured. Core losses predicted by the model are in good agreement with the measurement.
Material informatics for functional magnetic material discovery
Authors: Rowan-Robinson R. M. , Leong Z. , Carpio S. , Oh C. , Morley N. A.
Published: January 2024

Functional magnetic materials are used in a wide range of “green” applications, from wind turbines to magnetic refrigeration. Often the magnetic materials used contain expensive and/or scarce elements, making them unsuitable for long term solutions. Further, traditional material discovery is a slow and costly process, which can take over 10 years. Material informatics is a growing field, which combines informatics, machine learning (ML) and high-throughput experiments to rapidly discover new materials. To prove this concept, we have devised a material informatics workflow and demonstrated the core components of natural language processing (NLP) to extract data from research papers to create a functional magnetic material database, machine learning with semi-heuristic models to predict compositions of soft magnetic materials, and high-throughput experimental evaluation using combinatorial sputtering and high-throughput magneto-optic Kerr effect (MOKE) magnetometry. This material informatics workflow provides a quicker, cheaper route to functional magnetic materials discovery.
Skin permeability and magnetic susceptibility analysis of hyaluronic acid-based magnetized microneedles containing iron oxide nanoparticles
Authors: Choi Jong-Gu , Hasan Mahbub , Lee Sang-Suk
Published: January 2024

Iron oxide nanoparticles (NPs) are biocompatible, have excellent magnetic properties, respond to external magnetic fields, and have been used in many studies on drug delivery systems. In this study, hyaluronic acid (HA)–superparamagnetic microneedles containing superparamagnetic iron oxide nanoparticles were manufactured using HA as the matrix material. Optical and scanning electron microscopy (SEM) were used to investigate the characteristics of the magnetized microneedles (MMNs). The mechanical rigidity of MMNs for in vivo evaluation is expected to be sufficient, as evidenced by a transmittance greater than 90%. Additionally, the superconducting quantum interference device-vibrating sample magnetometer measurement results confirmed that the magnetic characteristics did not change, even after the magnetic nanoparticles (MNPs) were manufactured. The hysteresis curves of the NPs confirmed the maintenance of the magnetic properties, including a coercivity of 60 Oe and susceptibility of 4 × 10-6 emu/gOe. Based on these results, MNPs are expected to be useful as a delivery material for transdermal drug delivery systems, magnetic resonance imaging, and molecular imaging.
Surface receive coil dedicated for rat kidney with high sensitivity magnetic resonance imaging
Authors: Takahashi Masaharu , Fushimi Motofumi , Yabukami Shin , Sekino Masaki , Kuwahata Akihiro
Published: January 2024

We propose a novel method based on an inverse problem to design a single channel radio frequency (RF) receive coil for magnetic resonance imaging (MRI) with an optimized signal-to-noise ratio (SNR) for imaging the rat kidney. We identified a dedicated curved-surface coil design for use on the rat body surface utilizing inverse problem analysis using direct current calculation and quantitatively evaluated the indicators of coil performance using alternating current calculation. The proposed coil achieved increased SNR and signal intensity responses that were respectively 1.05- and 2-fold higher than those of conventional surface coils. In the future, we will fabricate a prototype coil and perform the MRI of the rat kidney to diagnose kidney diseases.
Design and analysis of a hybrid permanent magnet variable leakage flux motor for low core loss and wide speed range
Authors: Yang Mingwei , Quan Li , Zhu Xiaoyong , Xiang Zixuan , Fan Deyang , Fan Wenjie , Jiang Min
Published: January 2024

In this paper, a new hybrid permanent magnet variable leakage flux (VLF-HPM) motor is proposed. In order to enhance motor speed range, short arc-shaped and elliptical-shaped magnetic barriers are placed on the q-axis magnet circuit, realizing the so-called leakage flux effect. In addition, ferrite PMs are artfully designed, so self-leakage flux can be reduced while main flux is enhanced. The relationship among PM topology, flux barrier and flux-regulation capability are also investigated in detail. Finally, the electromagnetic performance of VLF-HPM motor is evaluated by the finite element analysis and compared with a conventional V-typed PM motor. It is noted that, compared with conventional V-typed PM motor, the VLF-HPM motor possesses lower core losses and a wider speed range, which offers a new research path for high-performance PM motor.
Impacts of VIE tagging and Rhodamine B immersion staining on two measures of performance for a small-bodied fish
Authors: Franklin P. A. , Crawford R. , van Ravenhorst W. B. , Baker C. F.
Published: January 2024

Context Passage efficiency is an important metric for quantifying the success of fish-passage remediation. Mark–recapture methods are typically employed to estimate fish-passage efficiency. Although biotelemetry methods have become a benchmark standard for such studies, they remain unfeasible for many small-bodies species because of the excessive size of electronic tags. Aims This study compares two commonly deployed marking methods that are potentially suitable for estimating passage efficiency for small-bodied species, namely, visible implant elastomer (VIE) tagging and batch immersion staining with Rhodamine B. Methods The critical swimming speeds and passage efficiency at a remediated culvert of Galaxias maculatus were compared for VIE-tagged, Rhodamine B-stained and control treatments. Key results Both critical swimming speeds and passage efficiency at the culvert were significantly lower in VIE-tagged Galaxias maculatus than in both control fish and fish stained with Rhodamine B. Conclusions Rhodamine B may be a suitable batch immersion stain for short-term (<4 day), non-destructive mark–recapture studies in small-bodied fishes, but VIE-tagging methods may result in underestimation of passage efficiency. Implications It is important to evaluate the impact of marking techniques on the outcomes of mark–recapture studies to ensure that estimates of passage efficiency are accurate.
Quantifying local stiffness and forces in soft biological tissues using droplet optical microcavities
Authors: Pirnat Gregor , Marinčič Matevž , Ravnik Miha , Humar Matjaž
Published: January 2024

Mechanical properties of biological tissues fundamentally underlie various biological processes and noncontact, local, and microscopic methods can provide fundamental insights. Here, we present an approach for quantifying the local mechanical properties of biological materials at the microscale, based on measuring the spectral shifts of the optical resonances in droplet microcavities. Specifically, the developed method allows for measurements of deformations in dye-doped oil droplets embedded in soft materials or biological tissues with an error of only 1 nm, which in turn enables measurements of anisotropic stress inside tissues as small as a few pN/μm2. Furthermore, by applying an external strain, Young’s modulus can be measured in the range from 1 Pa to 35 kPa, which covers most human soft tissues. Using multiple droplet microcavities, our approach could enable mapping of stiffness and forces in inhomogeneous soft tissues and could also be applied to in vivo and single-cell experiments. The developed method can potentially lead to insights into the mechanics of biological tissues.
Building on-chip cytoskeletal circuits via branched microtubule networks
Authors: Zaferani Meisam , Song Ryungeun , Petry Sabine , Stone Howard A.
Published: January 2024

Controllable platforms to engineer robust cytoskeletal scaffolds have the potential to create novel on-chip nanotechnologies. Inspired by axons, we combined the branching microtubule (MT) nucleation pathway with microfabrication to develop “cytoskeletal circuits.” This active matter platform allows control over the adaptive self-organization of uniformly polarized MT arrays via geometric features of microstructures designed within a microfluidic confinement. We build and characterize basic elements, including turns and divisions, as well as complex regulatory elements, such as biased division and MT diodes, to construct various MT architectures on a chip. Our platform could be used in diverse applications, ranging from efficient on-chip molecular transport to mechanical nano-actuators. Further, cytoskeletal circuits can serve as a tool to study how the physical environment contributes to MT architecture in living cells.
Constructing a high-precision virtual scene of mining equipment and coal seam roof and floor using actual mining data
Authors: Tao Cui , Jiacheng Xie , Wang Xuewen , Xin Zhang , Suhua Li , Mengyao Dong
Published: January 2024

This paper proposes a method of constructing a high-precision virtual scene of mining equipment, coal seam roof and floor using actual mining data to meet the industry's visualisation demands. By analysing the relationships between the shearer, scraper conveyor and coal seam, four kinds of coal seam floor construction methods are established on the basis of the shearer's running track, the cutting track, the running track of the supporting slipper and the shape of scraper conveyor. The virtual operation scene of the mining and transportation equipment is built in Unity3D to achieve a collaborative operation in a complex coal seam environment. By comparing the actual pitch angle with the virtual pitch angle of the shearer, it is found that the running track of the supporting slipper can better reflect the change trend of the coal seam floor. This method improves the accuracy of the virtual simulation of mining and transportation equipment and provides technical support for its virtual monitoring.
Fuzzy FMEA for the safety risk analysis of underground coal mining (a case study in Iran)
Authors: Rahimdel Mohammad Javad , Aryafar Ahmad , Vaziri Solmaz
Published: January 2024

Hazards in underground coal mines create an unsafe working environment for workers and equipment. This paper aims to analyze the safety risk in underground coal mining using an improved Failure Mode and Effect Analysis (FMEA) method. To achieve this, the causes of the main events that threaten the safety of the working environment were identified and discussed in a case study; Parvadeh Tabas coal mine, Iran. The Analytical Hierarchy Process (AHP) was applied to calculate the importance degree of each hazard. Then, the FMEA approach under the fuzzy environment was used for the safety risk analysis. Regarding the results of this study, the outburst-related hazards, failure to provide sufficient compressed air, and the electrical locomotive-related hazards have the highest level of safety risk. In this concept, it is possible to identify the leading causes of accidents and propose practical solutions to improve the safety conditions of the mine working places.
Mechanosensitive super-enhancers regulate genes linked to atherosclerosis in endothelial cells
Authors: Li Jin , Zhu Jiayu , Gray Olivia , Sobreira Débora R. , Wu David , Huang Ru-Ting , Miao Bernadette , Sakabe Noboru J. , Krause Matthew D. , Kaikkonen Minna U. , Romanoski Casey E. , Nobrega Marcelo A. , Fang Yun
Published: January 2024

Vascular homeostasis and pathophysiology are tightly regulated by mechanical forces generated by hemodynamics. Vascular disorders such as atherosclerotic diseases largely occur at curvatures and bifurcations where disturbed blood flow activates endothelial cells while unidirectional flow at the straight part of vessels promotes endothelial health. Integrated analysis of the endothelial transcriptome, the 3D epigenome, and human genetics systematically identified the SNP-enriched cistrome in vascular endothelium subjected to well-defined atherosclerosis-prone disturbed flow or atherosclerosis-protective unidirectional flow. Our results characterized the endothelial typical- and super-enhancers and underscored the critical regulatory role of flow-sensitive endothelial super-enhancers. CRISPR interference and activation validated the function of a previously unrecognized unidirectional flow-induced super-enhancer that upregulates antioxidant genes NQO1, CYB5B, and WWP2, and a disturbed flow-induced super-enhancer in endothelium which drives prothrombotic genes EDN1 and HIVEP in vascular endothelium. Our results employing multiomics identify the cis-regulatory architecture of the flow-sensitive endothelial epigenome related to atherosclerosis and highlight the regulatory role of super-enhancers in mechanotransduction mechanisms.
Tunable Three-Wavelength Fiber Laser and Transient Switching between Three-Wavelength Soliton and Q-Switched Mode-Locked States
Authors: Si 司 Zhi-Zeng 志增 , Dai 戴 Chao-Qing 朝卿 , Liu 刘 Wei 威
Published: January 2024

We report a passive mode-locked fiber laser that can realize single-wavelength tuning and multi-wavelength spacing tuning simultaneously. The tuning range is from 1528 nm–1560 nm, and up to three bands of soliton states can be output at the same time. These results are confirmed by a nonlinear Schrödinger equation model based on the split-step Fourier method. In addition, we reveal a way to transform the multi-wavelength soliton state into the Q-switched mode-locked state, which is period doubling. These results will promote the development of optical communication, optical sensing and multi-signal pulse emission.
Measurement of proton induced absolute production cross-section of 6.13, 6.92 and 7.12 MeV γ-rays from 16O(p,p
′γ
)16O reaction
Authors: Ranga V , Mazumdar I , Weppner S P , Panwar S , Sariyal R , Patel S M , Chavan P B , Rhine Kumar A K , Anil Kumar G
Published: January 2024

In this article, we report the absolute production cross-section of 6.13, 6.92 and 7.12 MeV γ-rays from the 16O(p,p

′

γ

)16O reaction for incident proton energy range of 8-16 MeV. Angular distributions of the three γ-rays have been measured for seven angles at 9 MeV proton energy. A detailed phenomenological optical model potential (OMP) was set up to analyse the cross-section data. The OMP parameters were optimised using elastic, polarization and total reaction data available in the literature for protons and neutrons. Low-lying states of 16O were coupled, the optical potential was deformed using deformation parameters, and several resonances were included in the calculations to account for the nuclear structure effects. The potentials so generated have been used to calculate the differential and total cross sections for both 16O(p,p

′

)16O and 16O(p,p

′

γ

)16O reactions. Our calculated cross-sections are in fairly good agreement with our measured data for 6.13, 6.92 and 7.12 MeV γ-rays. However, there still exist discrepancies in reproduction of the finer details of the cross sections. The comparisons of the calculations with the data bring forth the rather complex roles of channel couplings, resonances in the p+16O system and target deformation in the variation of the cross sections with projectile energy. The increased contribution of nuclear structure effects in light mass nuclei, leads to an apparent loss of predictive power of the theoretical calculation, as we approach the low-energy region of less than 10 MeV projectile energy.
Development of the occupational exposure during the production and application of radiopharmaceuticals in Germany
Authors: Vogt Julius , Oeh Uwe , Maringer Franz Josef
Published: January 2024

An increasing number of radiopharmaceuticals and proteins are available for diagnosing and treating various diseases. The demand for existing and newly developed pharmaceutical radionuclides and proteins is steadily increasing. The radiation exposure levels of workers in the radiopharmaceutical industry and nuclear medicine field are closely monitored, specifically their effective dose and equivalent dose, leading to the question, of whether the dawn of radiopharmaceuticals affects the occupational exposure level. This development is analyzed and evaluated with data from the German National Dose Register. Data shows that the effective dose in the work categories production and distribution of radioisotopes as well as nuclear medicine slightly decreased from 1997 to 2021. Over the same period, the hand equivalent dose in nuclear medicine increases steadily, with no discernible trend in production and distribution of radioisotopes. Over the past few decades, intentional efforts and measures have been taken to ensure radiation protection. Instruments for monitoring and dose reduction must be continuously applied. Given the low effective dose, the focus in future shall be on dose reduction following the as low as reasonably achievable principle. The development of the hand equivalent dose should be carefully observed in the upcoming years.
Factors affecting radiographers’ use of dose-reduction measures
Authors: Bazzi May , Afram Shilan Shamon , Ndipen Irine Maghanwi , Kåreholt Ingemar , Bjällmark Anna
Published: January 2024

This study investigates radiographers’ views on implementing dose-reduction measures, with a focus on verifying patient identity and pregnancy status, practising gonad shielding in men and using compression. An electronic questionnaire was distributed to radiographers working in general radiography and/or computed tomography. The questionnaire was based on factors from a framework for analysing risk and safety in clinical medicine. Ordered logistic regressions were used to analyse associations among factors and use of dose-reduction measures. In total, 466 questionnaires were distributed and 170 radiographers (36%) completed them. Clear instructions and routines, support from colleagues, knowledge and experience, a strong safety culture, managerial support and access to proper equipment influence the likelihood of using dose-reduction measures. The strongest associations were found between support from colleagues and verifying pregnancy status (OR = 5.65, P = 0.026), safety culture and use of gonad shielding (OR = 2.36, P = 0.042), and having enough time and use of compression (OR = 2.11, P = 0.003). A strong safety culture and a supportive work environment appears to be essential for the use of dose-reduction measures, and education, training and stress management can improve utilisation of dose-reduction measures.
Artificial intelligence model GPT4 narrowly fails simulated radiological protection exam
Authors: Roemer G , Li A , Mahmood U , Dauer L , Bellamy M
Published: January 2024

This study assesses the efficacy of Generative Pre-Trained Transformers (GPT) published by OpenAI in the specialised domains of radiological protection and health physics. Utilising a set of 1064 surrogate questions designed to mimic a health physics certification exam, we evaluated the models’ ability to accurately respond to questions across five knowledge domains. Our results indicated that neither model met the 67% passing threshold, with GPT-3.5 achieving a 45.3% weighted average and GPT-4 attaining 61.7%. Despite GPT-4’s significant parameter increase and multimodal capabilities, it demonstrated superior performance in all categories yet still fell short of a passing score. The study’s methodology involved a simple, standardised prompting strategy without employing prompt engineering or in-context learning, which are known to potentially enhance performance. The analysis revealed that GPT-3.5 formatted answers more correctly, despite GPT-4’s higher overall accuracy. The findings suggest that while GPT-3.5 and GPT-4 show promise in handling domain-specific content, their application in the field of radiological protection should be approached with caution, emphasising the need for human oversight and verification.
National survey to update the diagnostic reference levels in interventional radiology procedures in Italy: working methodology
Authors: D’Ercole L , Rosi A , Bernardi G , Compagnone G , Orlacchio A , Padovani R , Palma A , Grande S
Published: January 2024

Interventional Radiology (IR) deals with the diagnosis and treatment of various diseases through medically guided imaging. It provides unquestionable benefits to patients, but requires, in many cases, the use of high doses of ionizing radiation with a high impact on radiation risks to patients and to overall dose to the population. The International Commission on Radiological Protection introduced Diagnostic reference levels (DRLs) as an effective tool to facilitate dose verification and optimize protection for patients undergoing radiological procedures. In addition, EURATOM Council Directive 2013/59 and its Italian transposition (Legislative Decree 101/2020) have reiterated that DRLs must be established for many common radiological diagnostic procedures to compare the radiation dose delivered for the same diagnostic examination. Within this framework, Istituto Superiore di Sanità—Italian National Institute of Health (ISS)-, in collaboration with relevant Italian Scientific Societies, has provided documents on DRLs in radiological practices such as diagnostic and IR and diagnostic nuclear medicine. These reference documents enable National Hospitals to comply national regulation. The implementation of DRLs in IR is a difficult task because of the wide distribution of doses to patients even within the same procedure. Some studies have revealed that the amount of radiation in IR procedures is influenced more by the complexity of the procedure than by the weight of the patient, so complexity should be included in the definition of DRLs. For this reason, ISS promoted a survey among a sample of Italian Centers update national DRL in IR procedures with related complexity factors than can be useful for other radiological centers and to standardize the DRLs values. In the present paper the procedural methodology developed by ISS and used for the survey will be illustrated.