bluuebunny/crossref_metadata_2025 huggingface dataset:
A liquid–metal-based microscale calorimetric in-chip flow sensor for flow rate measuring
Authors: Deng Yuqin , Ye Zi , Deng Zhongshan , Hong Jie , Zhang Huimin , Gui Lin
Published: January 2024

This work proposes a liquid–metal-based calorimetric micro-flow sensor within a polydimethylsiloxane (PDMS) chip. It can measure the flow rate of fluid in microscale channels, with a range as low as several microliters per minute. This in-chip sensor is proposed to solve the issue of detecting the flow rate in microfluidic systems. To make the sensor compatible with PDMS microfluidic chips, low-melting-point gallium-based alloy and bismuth-based (bi-based) alloy are used to make the micro heater and bi-metal thermocouples, for these alloys can be easily injected into a PDMS chip to form electrodes. To minimize heat resistance (or temperature difference) between fluid and the detecting ends of thermocouples, these ends are directly exposed to liquid in the flow channel with the help of a special reversible bonding technology. Thermocouples are connected in series to improve the sensor’s response. A novel method to bond and electrically connect the sensor to a print circuit board is also elaborated. Since the calorimetric flow sensor is sensitive to heating power, fluid temperature and environment cooling, a dimensionless parameter less independent of these factors is deduced from heat transfer theory, and this idea is used in result processing to offset the bad effect. Experiments with pure water show that this sensor can be used to detect flow rates, with a resolution up to 4 µl min−1 mV−1 and a range of 12 µl min−1 in this case, and that at different heating powers, the thermal potential results vary significantly whereas the dimensionless results nearly keep the same. Present work indicates that this sensor has the potential to be integrated into a PDMS microfluidic system and to provide accurate and stable results if a dimensionless method is used in data processing.
Simulation analysis on the synergistic effect of vegetation ashes and charged particles on the gap electric field distortion
Authors: Lin Baisen , Gou Bin , Zhang Daoming , Xue Yuqian , Wang Rui , Xie Congzhen
Published: January 2024

Hill fires, a sort of ultra-natural disaster that poses a severe threat to the safe and stable operation of transmission lines, have become more frequent in recent years. Currently, the modeling research on the transmission line gap electric field distortion under hill fire conditions does not consider the synergistic effect of charged particles and ash particles, which would lead to the imperfect gap electric field distortion mechanism. Herein, a coupled multi-physics field simulation model of electric, thermal, fluid, chemical field and particle motion was constructed to analyze the electric field distribution and particle motion. Compared to the related simulation models, this study improves the simulation accuracy by around 407% by optimizing the structure and parameters of the simulation model. The FEM software COMSOL Multiphysics simulation results show that the percentage of ash entering the examined region of the AC conductor was 34.1% higher, and the percentage of connected ash was 45% higher, increasing the likelihood of gap breakdown compared to the DC conductor; the charge of ash (10−14 to 10−11) is significantly less than the saturation charge of ash (⩾10−3). Therefore, the charged particles change the motion characteristics of the ash primarily through the electric field force and dielectrophoresis force, while the ash-induced distortion of the electric field affects the spatial distribution of the charged particles, eventually, the background electric field undergoes significant distortion by the synergistic effect of the two. The results examine the inherent mechanism of gap electric field distortion at the microscopic level, which can provide theoretical support for understanding the transition phase of transmission line gaps from insulation to break down under hill fire conditions.
Significant enhancement of perpendicular magnetic anisotropy in Fe/MoSi2N4 by hole doping
Authors: Guo Fei , Xie Yuanmiao , Huang Xiaoqi , Li Feng , Liu Baosheng , Dong Xinwei , Zhou Jin
Published: January 2024

This study proposes a novel approach to enhanced the perpendicular magnetic anisotropy (PMA) of Fe adsorbed on a MoSi2N4 substrate through hole doping. First principles calculations are employed to investigate the PMA of freestanding Fe and Fe/MoSi2N4 complex system. It is found that the PMA of Fe atom slightly increases from freestanding Fe monolayer to the Fe/MoSi2N4 system, which is attributed to the overlap between Fe-3d and N-2p orbitals. More interestingly, it is found that the PMA of Fe atoms in Fe/MoSi2N4 can be further enhanced by hole doping, which enables the PMA to increase significantly, up to four times the original value. This finding provides a promising way to enhance the PMA in two-dimensional (2D) spintronic devices. These results offering potential applications in developing advanced 2D spintronic devices.
Enhancing magnetically driven microswimmer velocity via low Reynolds number hydrodynamic interactions
Authors: Sharanya S , Gupta Anurag , Singh T Sonamani
Published: January 2024

The motion of comoving magnetic microswimmers is modeled by considering the inter-hydrodynamic interactions (HI) under low Reynolds number conditions. The microswimmer is a two-link design consisting of a magnetic head attached to a slender tail via a torsional spring, and it is driven by an external planar oscillatory magnetic field. The inter-HI considered are the head-head and tail-tail interactions. The propulsion velocity for the comoving mode is calculated and compared with that of an isolated mode. The comparative results show that the comoving mode velocity can be either similar or greater than the isolated mode, depending on the actuation frequency. The parametric dependency results show that the velocity generated in comoving mode depends on the average separation distance and length-to-width ratio of the tail. For proof of concept, a low-cost fabrication protocol is implemented to design a millimeter-sized magnetic flagellated swimmer. The experimental result shows that the comoving swimming mode generates larger velocity in comparison to isolated swimming.
Ground-state phase diagram and universality of sequential topological valence-bond-solid quantum transitions in a mixed tetramer chain
Authors: Veríssimo Luan M , Pereira Maria S S , Strečka Jozef , Lyra Marcelo L
Published: January 2024

The ground-state ordering of a quantum mixed-spin Heisenberg tetramer chain composed of an alternate sequence of s = 1 and

S
=
3

/

2

dimers is studied in detail as a function of two considered exchange interactions ascribed to similar and dissimilar spin pairs. At zero magnetic field, the ferrimagnetic mixed spin-(1, 1, 3/2, 3/2) Heisenberg tetramer chain displays, depending on a mutual interplay between two considered exchange interactions, three distinct gapped valence-bond-solid phases separated by gap-closing quantum critical points. Using density-matrix renormalization group calculations we construct the full ground-state phase diagram as a function of the interaction ratio and magnetic field, which exhibits besides three gapped valence-bond-solid phases special Kosterlitz–Thouless and topological quantum critical points. A tangential finite-size scaling analysis is employed to obtain precise estimates of the zero-field valence-bond-solid transitions and unveil their common logarithmic correction to a power-law scaling of the correlation length.
Superconducting ternary hydrides in Ca-U-H under high pressure
Authors: Wu Juefei , Zhu Bangshuai , Ding Chi , Pei Cuiying , Wang Qi , Sun Jian , Qi Yanpeng
Published: January 2024

The research on hydrogen-rich ternary compounds attract tremendous attention for it paves new route to room-temperature superconductivity at lower pressures. Here, we study the crystal structures, electronic structures, and superconducting properties of the ternary Ca-U-H system, combining crystal structure predictions with ab-initio calculations under high pressure. We found four dynamically stable structures with hydrogen clathrate cages: CaUH12-Cmmm, CaUH12-Fd-3m, Ca2UH18-P-3m1, and CaU3H32-Pm-3m. Among them, the Ca2UH18-P-3m1 and CaU3H32-Pm-3m are likely to be synthesized below 1 megabar. The f electrons in U atoms make dominant contribution to the electronic density of states around the Fermi energy. The electron-phonon interaction calculations reveal that phonon softening in the mid-frequency region can enhance the electron–phonon coupling significantly. The T
c value of Ca2UH18-P-3m1 is estimated to be 57.5–65.8 K at 100 GPa. Our studies demonstrate that introducing actinides into alkaline-earth metal hydrides provides possibility in designing novel superconducting ternary hydrides.
Bosonic excitation spectra of superconducting
Bi2Sr2CaCu2O8+δ
and
YBa2Cu3O6+x
extracted from scanning tunneling spectra
Authors: Gozlinski Thomas , Henn Mirjam , Wolf Thomas , Le Tacon Matthieu , Schmalian Jörg , Wulfhekel Wulf
Published: January 2024

A detailed interpretation of scanning tunneling spectra obtained on unconventional superconductors enables one to gain information on the pairing boson. Decisive for this approach are inelastic tunneling events. Due to the lack of momentum conservation in tunneling from or to the sharp tip, those are enhanced in the geometry of a scanning tunneling microscope compared to planar tunnel junctions. This work extends the method of obtaining the bosonic excitation spectrum by deconvolution from tunneling spectra to nodal d-wave superconductors. In particular, scanning tunneling spectra of slightly underdoped

B

i
2

S

r
2

C
a
C

u
2

O

8
+
δ

with a

T

c

of 82 K and optimally doped

Y
B

a
2

C

u
3

O

6
+
x

with a Tc
of 92 K reveal a resonance mode in their bosonic excitation spectrum at

Ω

r
e
s

≈

63

 

meV

and

Ω

r
e
s

≈

61

 

meV

respectively. In both cases, the overall shape of the bosonic excitation spectrum is indicative of predominant spin scattering with a resonant mode at

Ω

r
e
s

<
2
Δ

and overdamped spin fluctuations for energies larger than 2Δ. To perform the deconvolution of the experimental data, we implemented an efficient iterative algorithm that significantly enhances the reliability of our analysis.
M-FISH evaluation of chromosome aberrations to examine for historical exposure to ionising radiation due to participation at British nuclear test sites
Authors: Lawrence Kirsty Josephine , Scholze Martin , Seixo Jose , Daley Frances , Al-Haddad Emily , Craenen Kai , Gillham Clare , Rake Christine , Peto Julian , Anderson Rhona
Published: January 2024

Veterans of the British nuclear testing programme represent a population of ex-military personnel who had the potential to be exposed to ionising radiation through their participation at nuclear testing sites in the 1950s and 1960s. In the intervening years, members of this population have raised concerns about the status of their health and that of their descendants, as a consequence. Radiation dose estimates based on film badge measurements of external dose recorded at the time of the tests suggest any exposure to be limited for the majority of personnel, however, only ∼20% of personnel were monitored and no measurement for internalised exposure are on record. Here, to in-part address families concerns, we assay for chromosomal evidence of historical radiation exposure in a group of aged nuclear test (NT) veterans, using multiplex in situ hybridisation (M-FISH), for comparison with a matched group of veterans who were not present at NT sites. In total, we analysed 9379 and 7698 metaphase cells using M-FISH (24-colour karyotyping) from 48 NT and 38 control veteran samples, representing veteran servicemen from the army, Royal Airforce and Royal Navy. We observed stable and unstable simple- and complex-type chromosome aberrations in both NT and control veterans’ samples, however find no significant difference in yield of any chromosome aberration type between the two cohorts. We do observe higher average frequencies of complex chromosome aberrations in a very small subset of veterans previously identified as having a higher potential for radiation exposure, which may be indicative of internalised contamination to long-lived radionuclides from radiation fallout. By utilising recently published whole genome sequence analysis data of a sub-set of the same family groups, we examined for but found no relationship between paternal chromosome aberration burden, germline mutation frequency and self-reported concerns of adverse health in family members, suggesting that the previously reported health issues by participants in this study are unlikely to be associated with historical radiation exposure. We did observe a small number of families, representing both control and NT cohorts, showing a relationship between paternal chromosome aberrations and germline mutation sub-types which should be explored in future studies. In conclusion, we find no cytogenetic evidence of historical radiation exposure in the cohort of nuclear veterans sampled here, offering reassurance that attendance at NTs sites by the veterans sampled here, was not associated with significant levels of exposure to radiation.
Clinical image quality assessment and mean glandular dose for full field digital mammography
Authors: Nassar Joyce , Rizk Chadia , Fares Georges , Tohme Carla , Braidy Chady , Farah Jad
Published: January 2024

This study aims to assess the image quality (IQ) of 12 mammographic units and to identify units with potential optimisation needs. Data for 350 mammography examinations meeting inclusion criteria were collected retrospectively from April 2021 to April 2022. They were categorised based on the medical reports into 10 normal cases, 10 cases displaying calcifications and 10 cases presenting lesions. Two radiologists assessed the IQ of 1400 mammograms, evaluating system performance per Boita et al’s study and positioning performance following European guidelines. To measure agreement between the two radiologists, the Cohen’s Kappa coefficient (κ) was computed, quantifying the excess of agreement beyond chance. The visual grading analysis score (VGAS) was computed to compare system and positioning performance assessments across different categories and facilities. Median average glandular dose (AGD) values for cranio caudal and medio lateral oblique views were calculated for each category and facility and compared to the national diagnostic reference levels. The health facilities were categorised by considering both IQ VGAS and AGD levels. Inter-rater agreement between radiologists ranged from poor (κ < 0.20) to moderate (0.41 < κ < 0.60), likely influenced by inherent biases and distinct IQ expectations. 50% of the facilities were classified as needing corrective actions for their system performance as they had IQ or high AGD that could increase recall rate and radiation risk and 50% of the health facilities exhibited insufficient positioning performance that could mask tumour masses and microcalcifications. The study’s findings emphasise the importance of implementing quality assurance programs to ensure optimal IQ for accurate diagnoses while adhering to radiation exposure guidelines. Additionally, comprehensive training for technologists is essential to address positioning challenges. These initiatives collectively aim to enhance the overall quality of breast imaging services, contributing to improved patient care.
Increasing the public awareness of justification
Authors: Kotre C J
Published: January 2024

One of the requirements of the UK Ionising Radiation (Medical Exposure) Regulations 2017 is that all medical exposures must be justified before the exposure can proceed. One of the main elements of justification is a determination that the medical benefits from the exposure will exceed the associated radiation detriment. The field of medical exposure to ionising radiation is in the rare position of having this explicit legal requirement for net benefit. In this article it is argued that, although separate information on benefit and detriment is also required for implied or explicit informed consent prior to exposure, justification comes first, is simple to explain, and is easily related to the commonly understood basis of medical ethics. It seems reasonable, therefore, to make patients and the public more aware of the protection that UK law already provides for them. A proposal for a single-sentence general statement on justification is made.
An enhanced perception health state assessment method for subway sliding plug door transmission system
Authors: Chen Gaige , Yang Yudong , Qi Hui , Wang Xianzhi , Ma Hongbo
Published: January 2024

The monitoring data (current and rotational speed) of the subway sliding plug door transmission system changed positively and negatively with the acceleration and weight of the door. How to perceive the changes is a challenging problem in the health state assessment of transmission system. To address this problem, an enhanced perception health state assessment method was proposed for the transmission systems. In the method, firstly, the equivalent resistance force is calculated by monitoring the current and rotational speed data according to mechanical dynamic knowledge. Secondly, the sensitive features of normal and abnormal states are screened out from the enhanced dataset constructed by current, rotational speed data, and equivalent resistance force data. Finally, the health state of the transmission system is assessed using an integrated learning algorithm. The effectiveness of the method is verified by benchmark experimental data, and the results indicate that the method has a higher accuracy with four classifiers and a broader suitable range with varying door acceleration and weight.
Quantitative, multi-species gas sensing using broadband terahertz time-domain spectroscopy
Authors: Zhao Chuxuan , Wang Weitian , Zhu Ning , Song Zihao , Chao Xing
Published: January 2024

The broadband terahertz wave, with its correspondence to the fingerprint spectra of gas molecules and relatively high transmittance through smoke, aerosol, and combustion environments, bears great potential for gas detection and combustion diagnostics. While access to rotational spectral fingerprints in the terahertz region provides opportunities for species-selective diagnostics with minimized background and cross interference, few studies have been devoted to direct, quantitative, and simultaneous analysis of multiple components exploiting the terahertz region. In this work, we achieve quantitative measurements of CO, NH3 and H2O gas concentrations at standard temperatures and pressures over a bandwidth of 1 THz, using direct absorption spectrum from femtosecond-laser-based terahertz time-domain spectroscopy. Spectral fitting of the fully resolved rotational lines yields good precision and accuracy with validation against calibrated mixtures. The estimated detection limits of the multi-species sensing system are 250 ppm m, 7 ppm m and 4 ppm m for CO, NH3 and H2O, respectively. The demonstration of quantitative, multi-species gas sensing indicates the feasibility and practical value of using broadband terahertz absorption spectroscopy for real-time, quantitative analysis and speciation of multicomponent gases in complicated practical environments such as combustion and multi-phase flows.
Structural descriptors evaluation for MoTa mechanical properties prediction with machine learning
Authors: Tao Tingpeng , Li Shu , Chen Dechuang , Li Shuai , Liu Dongrong , Liu Xin , Chen Minghua
Published: January 2024

Considering all possible crystal structures is essential in computer simulations of alloy properties, but using density functional theory (DFT) is computationally impractical. To address this, four structural descriptors were evaluated using machine learning (ML) models to predict formation energy, elasticity and hardness of MoTa alloys. A total of 612 configurations were generated by the Clusters Approach to Statistical Mechanics software and their corresponding material properties were calculated by DFT. As input features of ML models, the CORR and SOAP performed best (R
2 > 0.90, some up to 0.99), followed by Atomic-centred Symmetry Functions, while Coulomb matrix performed worst. Furthermore, SOAP shows excellent performance in extrapolation for larger supercell structures of the MoTa alloy system and transfer learning for the MoNb alloy system.
Nanotechnological advances in the treatment of epilepsy: a comprehensive review
Authors: Rai Garima , Sharma Surbhi , Bhasin Jasveen , Aggarwal Kanica , Ahuja Alka , Dang Shweta
Published: January 2024

Epilepsy is one of the most prevalent chronic neurological disorders characterized by frequent unprovoked epileptic seizures. Epileptic seizures can develop from a broad range of underlying abnormalities such as tumours, strokes, infections, traumatic brain injury, developmental abnormalities, autoimmune diseases, and genetic predispositions. Sometimes epilepsy is not easily diagnosed and treated due to the large diversity of symptoms. Undiagnosed and untreated seizures deteriorate over time, impair cognition, lead to injuries, and can sometimes result in death. This review gives details about epilepsy, its classification on the basis of International League Against Epilepsy, current therapeutics which are presently offered for the treatment of epilepsy. Despite of the fact that more than 30 different anti-epileptic medication and antiseizure drugs are available, large number of epileptic patients fail to attain prolonged seizure independence. Poor onsite bioavailability of drugs due to blood brain barrier poses a major challenge in drug delivery to brain. The present review covers the limitations with the state-of-the-art strategies for managing seizures and emphasizes the role of nanotechnology in overcoming these issues. Various nano-carriers like polymeric nanoparticles, dendrimers, lipidic nanoparticles such as solid lipid nanoparticles, nano-lipid carriers, have been explored for the delivery of anti-epileptic drugs to brain using oral and intranasal routes. Nano-carries protect the encapsulated drugs from degradation and provide a platform to deliver controlled release over prolonged periods, improved permeability and bioavailability at the site of action. The review also emphasises in details about the role of neuropeptides for the treatment of epilepsy.
Defect-guided self-tearing in graphene
Authors: Li Fengwei , Kang Zhan , Li Ming
Published: January 2024

The two-dimensional to three-dimensional configuration transition through self-tearing promises the engineering and promising applications of graphene. However, it is challenging to control the tearing path on demand through common thermal and interfacial treatments. In this manuscript, a defect-guided self-tearing technique is proposed to generate wider, longer, and even curved and serrated configurations, which is impossible for defect-free graphene. The underlying tearing mechanisms regarding the advancing displacement are disclosed through molecular dynamics simulations and theoretical model. This study provides a useful guidance to the implementation of complex and functional three-dimensional graphene structures.
Experiments with a spinning coin
Authors: Cross R
Published: January 2024

Two experiments are described with a spinning coin to examine the effect of adding a small mass near the edge of the coin. The effect is the same as that with a Tippe top, where the top inverts since the centre of mass rises.
Rotating ring on a horizontal rod
Authors: Cross Rod
Published: January 2024

A simple experiment is described where a metal ring was spun by hand in a vertical plane on a horizontal rod. The ring rotated about one hundred times before it fell onto the rod. The physics of the problem involves rotation of the ring in a circular path around the rod, plus rotation of the ring at a lower frequency about its own axis. It is a slightly more challenging problem than the standard loop-the-loop demonstration.
A novel split-gate trench MOSFET embedded with a high-k pillar for higher breakdown voltage
Authors: Huang Li , Li Xiaojin , Sun Yabin , Shi Yanling
Published: January 2024

A novel split-gate trench MOSFET embedded with a high-k pillar (HKP SGT-MOS) is proposed in this study. Numerous electric displacement lines are allowed to enter the high-k pillar introduced beneath the split gate, thus relieving the crowding of the electric field at the bottom corner of the split gate. Therefore, the HKP SGT-MOS can achieve a higher breakdown voltage (BV) without sacrificing its forward conduction. Various dielectrics for the high-k pillar, such as SiO2, Si3N4, Al2O3 and HfO2, are investigated. The results reveal that HfO2 has the largest figure of merit (FOM) and BV. The characteristics of the HKP SGT-MOS have also been validated by the Technology Computer-Aided Design simulation, and the BV and (FOM = BV 2/R
on,sp) are 258.3 V and 37.46 MW cm−2, achieving 36.7% and 87.02% improvement compared to the conventional SGT-MOS (CSGT-MOS), and 18.4% and 38.59% improvement compared to the SGT-MOS with short split-gate (SSGT-MOS). Moreover, the influence of the drift doping concentration, the mesa width, the length of the drift region and the width of the split gate/high-k pillar are also studied to optimize the proposed HKP SGT-MOS.
Terahertz dielectric properties of Fe3O4 thin films deposited on Si (100) substrate
Authors: Khandelwal Ashish , Sharath Chandra L S , Sharma Shilpam , Sagdeo Archna , Choudhary R J , Chattopadhyay M K
Published: January 2024

Fe3O4 is considered to be a promising material for terahertz spintronic applications as well as for stealth technology. However, the optical properties of Fe3O4 in the thin film form at terahertz frequencies are not reported in literature. In this article, we present the frequency and temperature dependence of dielectric permittivity (ε
1) and optical conductivity (σ
1) of Fe3O4 films deposited on Si substrate. The σ
1 of these films show absorption peaks related to charge localization and shallow impurities. It is also observed that the Fe2O3/Fe3O4 composite films have large σ
1 and ε
1 indicating their potential use for stealth technology applications. The overall optical properties are found to depend strongly on the microstructure and defects, such as, the grain size and the presence of grain boundaries, anti-phase boundaries, strain disorder due to lattice mismatch and/or the Fe+2/Fe+3 ratio.
Fast and accurate electromagnetic modeling of non-insulated and metal-insulated REBCO magnets
Authors: Pardo Enric , Fazilleau Philippe
Published: January 2024

REBCO high-temperature superconductors are promising for all-superconducting high-field magnets, including ultra-high field magnets. Non-insulated (NI) and metal-insulated (MI) windings are a good solution for protection against electro-thermal quench. Design and optimization requires numerical modelling of REBCO inserts for high-field magnets. Here, we detail a fast and accurate two-dimensional cross-sectional model for the electromagnetic response of NI and MI coils, which is based on the minimum electro magnetic entropy production. Benchmarking with an A − V formulation method on a double pancake coil shows good agreement. We also analyse a fully superconducting 32 T magnet with a REBCO insert and a low-temperature superconducing outsert. In particular, we analyse the current density, the screening current induced field (SCIF), and the AC loss. We have shown that metal-insulated coils enable transfer of angular current in the radial direction, and hence magnet protection, while keeping the same screening currents and AC loss of insulated coils, even at relatively high ramp rates of 1 A s−1. Surprisingly, soldered coils with low resistance between turns present relatively low AC loss for over-current configuration, which might enable higher generated magnetic fields. The numerical method presented here can be applied to optimize high-field magnets regarding SCIF in MI or NI magnets. It also serves as the basis for future electro-thermal modelling and multi-physics modelling that also includes mechanical properties.
Fractional approach to evolution of the magnetic field lines near the magnetic null points
Authors: Durmaz Hasan , Özdemir Zehra , Sekerci Yadigar
Published: January 2024

In this work, the magnetic reconnection model near null points in 3D space will be investigated using fractional calculations in the 3D magnetohydrodynamic framework. For the initial magnetic configuration (without external currents), we reformulated the numerically solved boundary initial value problem using fractional calculations. We studied the 3D Magnetic reconnection states and the behavior of the magnetic field around the null point and the null line. We also analyzed the fractional significance of charged particle motions in Killing magnetic fields. Moreover, the obtained results were visualized, and a comparison was made between the results obtained from integer and fractional calculations.
AuNP decorated aegle marmelos leaf as SERS substrate for trace detection of antibiotics and machine learning based classification
Authors: Sarma Dipjyoti , Marak Macduf R , Chetia Indrani , Badwaik Laxmikant S , Nath Pabitra
Published: January 2024

Surface-enhanced Raman spectroscopy (SERS) has emerged as a reliable molecular spectroscopic technique for trace detection of chemical and biological samples. Present study illustrates a new SERS platform which has been obtained through surface adsorption of gold nanoparticles (AuNP) on a microscopically roughened surface of aegle marmelos (AM) leaf. The micro-structured patterns of the AM leaves promote the generation of hotspot regions for the surface deposited AuNPs thus, aids in electromagnetic enhancement for the scattered Raman signals from the sample. For the proposed SERS platform, with rhodamine6G (R6G) as an analyte, the limit of detection (LoD) was found to be 0.88 nM. The applicability of the designed SERS was realized through detection and quantification of two commonly used antibiotics- Ceftriaxone (CEFTR) and Ceftiofur sodium (CEF-Na) residues from cow milk samples. Furthermore, a dimensionality reduction method known as principal component analysis (PCA) and an optimal machine learning-based model were built to categorize the analytes in the milk samples. The suggested machine learning model’s classification accuracy was found to be 94%.
Mathematical formulae for neutron self-shielding properties of media in an isotropic neutron field
Authors: Elmaghraby Elsayed K , Mahmoud Ateia W , Salama E , Elghazaly A , El-fiki S A
Published: January 2024

In the current study, an ab initio derivation of the neutron self-shielding factor to solve the complex neutron transport problem of the decrease of the neutron flux as it penetrates into a material placed in an isotropic neutron field having equal flux in all directions. The theory of steady-state neutron transport was employed, starting from Stuart’s formula, to derive simple analytical formulae based on the integral cross-section parameters. The formulae could be adopted by the user according to various variables, such as the neutron flux distribution and geometry of the simulation at hand. The concluded formulae of the self-shielding factors comprise an inverted sigmoid function normalized with a weight representing the ratio between the macroscopic total and scattering cross-sections of the medium. The general convex volume geometries are reduced to a set of chord lengths, while the neutron interaction probabilities within the volume are parameterized to the epithermal and thermal neutron energies. The arguments of the inverted-sigmoid function were derived from a simplified version of neutron transport formulation. The derived analytic formulae agreed greatly with the experimental observations for different elements and geometries.
Photodegradation of methylene blue dye using graphene oxide incorporated, post-transition metal doped zinc oxide thin films by spray pyrolysis
Authors: Paul John , Dhivyaprasath K , Ashok M , Kumar M C Santhosh
Published: January 2024

Photocatalytic activity of graphene oxide incorporated pure and metal doped zinc oxide thin films were studied against methylene blue dye under simulated solar irradiation. Thin films were deposited on a glass substrate using an automated spray pyrolysis technique at a temperature of 425 °C. Aluminium, gallium, and indium were the post-transition metals used for doping. Graphene oxide content in the precursor solution was fixed at 0.00375 g/l. The formation of the wurtzite structure of zinc oxide has been confirmed using structural analysis. The average crystallite size of all the thin film samples was found to be in the range of 45–55 nm. The morphology and elemental composition of the films were studied using scanning electron microscopy and energy-dispersive x-ray spectroscopy. The energy band gap of the material was determined from UV–vis-NIR spectroscopic measurements using Tauc’s plot and it is in the range of 3.25–3.28 eV. Photoluminescence spectra of the as-deposited films were recorded. Intensity of the near band emission at 395 nm was found to decrease upon metal doping, indicating a better photocatalytic property. All the films were used for heterogeneous photocatalysis and the indium doped zinc oxide thin film incorporated with graphene oxide was found to be a better catalyst with an efficiency of 94.9% for degrading methylene blue dye in 180 min.
Energy gap measurements based on enhanced absorption coefficient calculation from transmittance and reflectance raw data
Authors: Allaham Mohammad , Dallaev Rashid , Burda Daniel , Sobola Dinara , Nebojsa Alois , Knápek Alexandr , Mousa Marwan S , Kolařík Vladimír
Published: January 2024

The absorption coefficient plays an important role in studying and characterizing semiconducting materials. It is an important parameter to study the mechanism of photons absorption within the structure of the studied material. Thus, it helps to study the several types of charge carrier transport along with the energy band structure and its defects. In literature, a formula was reported to precisely calculate the absorption coefficient from raw data of transmittance and reflectance of electromagnetic radiation. However, the reported formula has several issues limiting its validity in the literature. In this paper, we provide a more mathematically accurate form of this equation to precisely obtain the absorption coefficient from the raw data, by considering the total internal reflection at the different interfaces. Moreover, the equation is tested by simulated data and is applied to study the optical characteristics of a single-component epoxy resin from its transmittance and reflectance raw data.
Carrier density distribution in AlGaAs/GaAs superlattices with different numbers of quantum wells determined by capacitance-voltage profiling
Authors: Vasilkova E I , Pirogov E V , Sobolev M S , Baranov A I , Gudovskikh A S , Khabibullin R A , Bouravleuv A D
Published: January 2024

The charge carrier density distribution in uniformly doped AlGaAs/GaAs superlattices with layer thicknesses of 1.5/10 nm and different numbers of quantum wells was studied. Both energy band theory and capacitance–voltage profiling were used to determine the carrier concentration profiles of the structures. During the analysis of the experimental and simulated capacitance–voltage characteristics, it was found that the maximum electron concentrations increase with an increase in the number of quantum wells from ∼

7.1
⋅

10

16

cm

−
3

for three wells to ∼

9.3
⋅

10

16

cm

−
3

for 25 wells with an overall superlattice doping level of ∼

10

17

cm

−
3

.
Comparison of partial and deep energy detachment behaviors with Ar seeding on EAST new corner slot divertor
Authors: Li Kedong , Wang Rong , Yang Zhongshi , Wu Kai , He Tao , Jia Guozhang , Lin Xin , Meng Lingyi , Yu Lin , Zhang Bin , Wu Jinhua , Duan Yanmin , Mao Songtao , Zang Qing , Zhang Ling , Zhang Tao , Wang Fudi , Wang Shouxin , Yuan Qiping , Wang Liang , Luo Guang-Nan
Published: January 2024

It is necessary for future fusion reactor to reduce the heat fluxes on the entire divertor target, especially if view of long pulse high performance operation. In recent EAST experiments, partial energy detachment without confinement degradation, and deep energy detachment with protection of the entire divertor target have both been confirmed on EAST corner slot divertor by argon (Ar) seeding, which can provide reference for the divertor protection on future fusion reactors. In the deep energy detachment state, the electron temperature T
et along entire lower outer divertor target decreases to less than 10 eV and heat fluxes are also strongly mitigated with peak heat flux reduction of more than 90%. Compared to the attached state, there is a moderate confinement degradation with H
98,y2 from ∼1 to ∼0.9 because of Ar radiation in the core region. This confinement degradation can be avoided in the partial energy detachment state, where the radiative power losses in the core are reduced. The experiment and SOLPS-ITER simulation results show that there is no decrease of particle flux js
on the divertor target in the partial energy detachment state because the momentum loss in the SOL region is not strong enough. With increasing Ar seeding, there is a js
decrease in the deep energy detachment state. The increases of momentum and power losses in the SOL region, and the decrease of upstream pressure all contribute to the js
reduction.
Modeling of frequency-sweeping Alfvén modes in the TJ-II stellarator
Authors: Ghiozzi A.G. , Mantsinen M.J. , Pastells P. , Spong D.A. , Melnikov A.V. , Eliseev L.G. , Sharapov S.E.
Published: January 2024

Alfvénic activity has been observed in the TJ-II stellarator which resembles the frequency sweeping demonstrated by Alfvén cascade modes in tokamaks. A numerical validation study was conducted using a reduced magnetohydrodynamic (MHD) model to show that such modes could only have been observed in discharges where the rotational transform profile was non-monotonic. During experiments, coil current was varied which resulted in shifting of the minimum value of the rotational transform profile. To mimic this effect, we study the Alfvénic activity predicted by the reduced MHD model for a set of input rotational transform profiles with varying minima. A mode is found whose toroidal and poloidal mode numbers match those predicted in experiments which sweeps downward/upward in frequency as the minimum value of the rotational transform profile is increased/decreased. The results serve as a demonstration of the validity and utility of MHD spectroscopy.
Enhancement of ECCD by the current condensation effect for stabilizing large magnetic islands caused by neoclassical tearing modes in tokamak plasmas
Authors: Liu Tong , Wang Zheng-Xiong , Wei Lai , Wang Jialei , Reiman Allan
Published: January 2024

The radio frequency current condensation effect reported in Reiman and Fisch (2018 Phys. Rev. Lett.
121 225001) is modeled in the nonlinear resistive magnetohydrodynamic code. A series of numerical investigations have been performed to investigate the enhancement of electron cyclotron current drive (ECCD) by the current condensation effect during the control of neoclassical tearing mode (NTM) in tokamak plasmas. In the numerical model, both the parallel transport and the perpendicular transport of electron temperature are considered. The EC driven current and driven perturbed electron temperature can nonlinearly evolve within the given magnetic configuration and eventually reach saturation states. The input power threshold of ECCD and the fold bifurcation phenomenon are numerically verified via nonlinear simulations. The numerical results show good agreements with the analytical results. Moreover, spatial distributions of EC current for the two solutions at different condensed level are displayed. The control effectiveness of ECCD for large NTM islands has been evaluated while considering the current condensation effect. While taking into account current condensation effect, for a sufficiently large input power, a larger island can be more effectively stabilized than a smaller one, which suggests a reassessment of the previous idea that the ECCD should always be turned on as early as possible. The potential physics mechanism behind the ECCD control have all been discussed in detail. Furthermore, the condensation effect is found to have favorable effects on the radial misalignment of ECCD. In the consideration of the situation for extremely localized control needs, a highly peaked heating profile is adopted to verify that the fold bifurcation phenomenon still exists and the current condensation effect can still take effect in this extreme condition.
Third order nonlinearity examined by pulsed and CW lasers: an organic urea barbituric acid (UBA) single crystal for optical limiting application with DFT study
Authors: Suresh A , Jauhar RO MU , Girisun T C Sabari , Manikandan N , Vinitha G
Published: January 2024

Bulk size of urea barbituric acid single crystal which has not been reported earlier was successfully grown by slow evaporation solution growth method. Single-crystal XRD brought out the lattice constant and the crystal system is observed to be monoclinic with space group P. Functional group of UBA were determined by FT-IR. UBA crystal is entirely visible from 270 to 900 nm with linear optical energy gap value to be 4.50 eV. The observed HOMO–LUMO energy gap was 5.21 eV. Thermally, UBA crystal is found to be stable up to 184˚°C. The Cp value of UBA increases from 1.21 to 1.58 J g−1K−1 with the temperature difference from 30 to 100˚°C. UBA shows good photoconductive nature and it found to be positive and Laser Damage Threshold (LDT) value of UBA crystal is 0.97 GW cm−2. Hardness testing confirms that UBA crystal belongs to soft nature category. Dielectric properties of UBA crystal are studied as a function of frequency and temperature. Third order NLO properties of the UBA crystal were studied under CW and pulsed lasers (ns) regimes using Z-scan technique. Good Optical limiting (OL) response (2.2860 х 1012 W/m2) confirms the efficiency of UBA crystal to be used as optical limiters for protection towards short pulse lasers.
QPI assay of fibroblasts resilience to adverse effects of nanoGO clusters by multimodal and multiscale microscopy
Authors: Valentino Marika , Pirone Daniele , Béhal Jaromir , Mugnano Martina , Castaldo Rachele , Lama Giuseppe C , Memmolo Pasquale , Miccio Lisa , Bianco Vittorio , Grilli Simonetta , Ferraro Pietro
Published: January 2024

Graphene is considered a possible drug deliver in nanomedicine for its mechanical, physical and chemical characteristics. Thus, studying graphene biocompatibility is pivotal to contribute to the modern nano-therapy science. The coexistence between cells and graphene should be analysed using non-invasive technologies and thus quantitative phase imaging (QPI) modalities are suitable to investigate the morphometric evolution of cells under nanomaterial exposure. Here, we show how a multimodal QPI approach can furnish a noninvasive analysis for probing the dose-dependent effect of nanoGO clusters on adherent NIH 3T3 fibroblast cells. We rely on both digital holography and Fourier ptychography (FP) in transmission microscopy mode. The former allows accurate time-lapse experiments at the single cell level. The latter provides a wide field of view characterization at the cells network level, thus assuring a significant statistical measurement by exploiting the intrinsic large space-bandwidth product of FP. The combination of these two techniques allows one to extract multimodal information about the cell resilience to adverse effects of nanoGO in the surrounding buffer, namely through quantitative, multi-scale, and time-resolved characterization.
Measurement of ultrashort laser pulses with a time-dependent polarization state using the d-scan technique
Authors: Díaz Rivas Daniel , Raab Ann-Kathrin , Guo Chen , Viotti Anne-Lise , Sytcevich Ivan , L’Huillier Anne , Arnold Cord
Published: January 2024

The dispersion scan (d-scan) technique is extended to measurement of the time-dependent polarization state of ultrashort laser pulses. In the simplest implementation for linearly polarized ultrashort pulses, the d-scan technique records the second harmonic generation spectrum as a function of a known spectral phase manipulation. By applying this method to two orthogonally polarized projections of an arbitrary polarized electric field and by measuring the spectrum at an intermediate angle, we can reconstruct the evolution over time of the polarization state. We demonstrate the method by measuring a polarization gate generated from

6

f
s

pulses with a combination of waveplates. The measurements are compared to simulations, showing an excellent agreement.
Rotating magnetocaloric effect in polycrystals—harnessing the demagnetizing effect
Authors: Almeida R , Freitas S C , Fernandes C R , Kiefe R , Araújo J P , Amaral J S , Ventura J O , Belo J H , Silva D J
Published: January 2024

Climate change and the increasing demand for energy globally have motivated the search for a more sustainable heat-pumping technology. Magnetic refrigeration stands as one of the most promising alternative technologies for clean and efficient heat pumps of the future. The rotating magnetocaloric effect (RMCE) has previously been studied in materials with magnetocrystalline anisotropy due to its potential to improve devices by requiring only a single magnetic field region, but these materials are fragile and costly to obtain, making them inviable for applications. It has been shown that by exploiting the demagnetizing effect, an RMCE is, in fact, attainable in any polycrystalline magnetocaloric sample with an asymmetric shape, without requiring magnetocrystalline anisotropy. Using gadolinium as a case study, we provide a theoretical framework for computing the demagnetizing field-based RMCE and present thorough experimental verification for different magnetic field intensities and a wide temperature range. Direct measurements of the RMCE in gadolinium reveal that a significant adiabatic temperature difference (1.2 K) and refrigerant capacity (7.44 J kg−1) can be attained within low magnetic field amplitudes (0.4 T). Utilizing lower magnetic field intensities in a magnetocaloric heat pump can significantly diminish the need for permanent magnet materials, thus reducing the overall device cost, size, and weight, ultimately enhancing the feasibility of mass-producing such devices.
Electrostatic chuck having compliant multi-beam structures with rotatable bipolar pad-shaped electrodes
Authors: Taoka Yuki , Ryo Tomohiro , Xu Sanchuan , Saito Shigeki
Published: January 2024

The demand for the manipulation of flexible film-like objects and those with non-planar surfaces, which cannot be handled using current technologies, has increased considerably. A bipolar electrostatic chuck (ESC) is a device that clamps target objects using a uniform electrostatic force. Traditional ESCs cannot satisfy these demands because of their planar surfaces. Bipolar ESCs with a compliant multi-beam assembly have been proposed to manipulate such objects while leveraging the uniform force distribution of ESCs. Although the proposed compliant ESCs have the potential for such manipulations, increasing the attractive force remains a critical technical issue. This study aims to develop a compliant ESC with pad-shaped bipolar electrodes connected to beam tips with rotational degrees of freedom (RDOFs). Four ESC models with pad-shaped electrodes with different RDOFs between zero and three and one without a pad-shaped electrode are fabricated via 3D printing. The experimental comparison of the five models indicates that an increase in the RDOFs significantly improves the attractive force of each electrode. The high potential of compliant ESCs with three RDOFs at the beam tips is illustrated using three different demonstrations: picking and placing dielectric films, a rigid object with a plane surface, and a rigid object with a curved surface. The results provide insights into the development of industrial electrostatic grippers.