bluuebunny/crossref_metadata_2025 huggingface dataset:
Strain regulation of the photoelectric performance of 2D InSe–AlAs vdW heterojunction: a DFT study
Authors: Yan Shenlang , Li Hui , Liu Chaofei , Xiang Shaohui , Long Mengqiu
Published: December 2024

Two-dimensional van der Waals heterojunctions (vdWs) have already garnered extensive and significant attention due to the excellent properties of smooth heterointerface, tunable band gap, and high carrier mobility. Inspired by the successful formation of vdWs heterojunctions, the electronic structure and photoelectric properties of devices based on InSe–AlAs vdW heterojunction are deeply and systematacially studied by using density-functional theory combined with the non equilibrium Green’s function approach. Six special configurations of InSe–AlAs vdW heterojunction were established by translational sliding InSe on AlAs monolayer, and the AA stacking model was identified as the most stable stacking structure. After the introduction of the horizontal and vertical strains, we observed that the band gap value continued to decrease with increasing the compression or tensile conditions. Further investigating the light absorption properties of the InSe–AlAs heterojunction under different strains, it found that an excellent light absorption characteristics with a wide and strong absorption peak within the UV range, especially at the light absorption coefficient can be up to 105. Finally, a nanodevice based on InSe–AlAs vdW heterojunction is designed to analyze the strain-induced photoconductivity changes, and the vertical strain could effectively regulate the photocurrent peaks. Therefore, electronic and photoelectric properties of vdW heterojunction can be highly tuned by tuning applied extra strains. This research will help expand the application of InSe–AlAs heterojunctions in the field of optoelectronics, and provide a theoretical basis.
2D-phononic system with local phase transition and reconfigurable non-contact modulation
Authors: Yu Guanliang , Jiang Chun , Li Yigui
Published: December 2024

Contactless tuning of signals represents a promising avenue for advancing topological phononics and photonics devices, particularly in the frequency and spatial domains. For topological phase transitions, breaking the spatial inversion symmetry geometrically to obtain an open topological band gap is a typical way to introduce perturbations. This approach has great limitations in achieving reconfigurable topological protection routes. We present a thermally modulated two-dimensional elastic topological insulator made from a patterned substrate and a temperature-sensitive vanadium dioxide film, allowing elastic waves to propagate in the suspended region of the 2D material. The topological phase transition is activated by locally heating a portion of the unit cell. This heating induces a phase transition in the material by exploiting changes in mechanical properties, achieving symmetry breaking. The topological valley-locked states with strong localization at the interface are obtained by placing unit cells with different chirality adjacent to each other at the omnidirectional bulk band gap. Full-field simulations confirm both the reconfigurability of arbitrary paths and the robustness of the induced waves against defects. Eliminating the need for pre-etched topological protection paths on patterned substrates enhances flexibility in both manufacturing and application. This innovative scheme employs localized temperature control at the unit cell scale to achieve effects akin to approximately 10% geometric symmetry breaking, thereby significantly reducing precision manufacturing requirements. Moreover, localized thermal modulation holds considerable potential for improving modulation rates while minimizing energy loss.
Investigation on capacitively coupled He discharges with a structured electrode and effective design of a high-density and uniform plasma
Authors: Liang Ying-Shuang , Li Peng-Bo , Zhang Yu-Ru , Wang You-Nian
Published: December 2024

In this paper, a fluid model is performed to investigate the effect of a structured electrode on capacitively coupled helium discharges operated at 13.56 MHz with 100 V peak-to-peak voltage, and 200 Pa. Compared to discharges with conventional planar electrodes, it is found that the plasma density produced by the structured electrode is raised by 28.5%–161.2% from

1.86
×

10

15

m

−
3

as the trench size (i.e. width and depth) in structured electrode varies. The results also indicate that the trench dimensions have a great effect on the plasma characteristics under the operating conditions in this study. With the increase of trench width, the plasma density below the trench region increases at trench widths lower than 22 mm, after which the opposite trend is observed. As the trench depth varies from 5 mm to 25 mm, the plasma density increases monotonously from

2.46
×

10

15

m

−
3

to

4.86
×

10

15

m

−
3

. Based on the results above, a modified ring-shaped structured electrode (MRSE) is proposed to successfully generate a large-area uniform and high-density plasma by adjusting the trench dimensions, position and number according to the discharge conditions. Compared to the flat electrode case, the plasma density and radial uniformity rise to 94.2% and

3.25
×

10

15

m

−
3

from 92.2% and

2.49
×

10

15

m

−
3

, respectively, with the adoption of MRSE. The simulation results also validate potential of the structured electrode as an effective tool in improvement of plasma processing.
Microstructure evolution and thermoelectric behaviour of directionally solidified Bi2Te3–Ga2Te3 eutectic alloy
Authors: Pal Varinder , Legese Surafel Shiferaw , Sreeram P R , Chattopadhyay Kamanio , Paliwal Manas , Tiwary Chandra Sekhar
Published: December 2024

Thermoelectric (TE) materials are known for efficiently converting thermal to electrical energy, and vice versa. Multiphase TEs offer better freedom to tune the TE properties of such materials by varying individual phase fractions, microstructural morphology, interface density controls, etc. These controlled changes in microstructural features can be achieved by directional solidification. Bi2Te3-Ga2Te3 based TEs have been reported with enhanced TE performance. In the present study, alloys with a combination of these phases were developed using a eutectic composition from the pseudo-binary phase diagram of Bi2Te3–Ga2Te3. The alloys were fabricated using the vertical Bridgman method with three different solidification velocities (V), namely 1000 (E1), 200 (E2) and 10 (E3) μm s−1, at a constant temperature gradient of 35 K cm−1 at the solid/liquid interface. Microstructural features show a significant change in the morphology and the interlamellar spacing between two adjacent Ga2Te3 lamellae in alloys E1, E2 and E3. In addition, x-ray diffraction patterns suggest changes in the lattice parameters of Bi2Te3 and Ga2Te3 for all alloys. Significant change in the macrotexture of the different alloys was observed along the growth direction. The highest power factor of 1.6 mW mK−2 was recorded for alloy E2 at room temperature. Alloy E2 shows the highest figure of merit among all the alloys investigated (0.38 at room temperature), attributed to the highest S value of 201.7 μV K−1 at room temperature. In addition, the total thermal conductivity of all alloys was around 1.33 W mK−1 at 307 K, while alloy E1 has the smallest lattice and bipolar thermal conductivity.
A temperature compensation method for fiber Bragg gratings using negative thermal expansive β-eucryptite packaging
Authors: Qiao Yujing , Zhang Wen , Chen Guanghui , Wen Ke , Zhu Lianqing
Published: December 2024

Fiber optic sensing measurements hold significant potential for various applications, but temperature compensation of fiber Bragg grating (FBG) remains a formidable challenge. This paper introduces the utilization of β-eucryptite as an encapsulation material for FBG, exploiting its negative thermal expansion property to achieve temperature compensation. A two-point adhesive sealing technique was employed to affix FBG to the β-eucryptite substrate. While bare FBG and sensors encapsulated in 7075 aluminum alloy served as comparison. Experimental outcomes reveal that the FBG encapsulated in β-eucryptite exhibits temperature sensitivities of 1.67 pm °C−1 within the temperature ranges of −30 °C to 150 °C. In contrast, bare FBG and sensor encapsulated with 7075 aluminum alloy display temperature sensitivities of 10.46 pm °C−1 and 37.31 pm °C−1, respectively. The use of β-eucryptite for sensor encapsulation effectively reduces the temperature sensitivity of FBG. This temperature compensation method is straightforward yet promising and has great potential in aerospace and precision instrument measurement.
Dynamic behavior of permanent magnet synchronous motor rotor radial eccentricity
Authors: Huang Fengchao , Wang Zhengqi , Chen Changzheng , Wang Tong , Yang Mingzheng , Fu Hao
Published: December 2024

With the rapid advancement of new energy vehicles, permanent magnet synchronous motors are being increasingly utilized. Among the various faults that can occur, rotor eccentricity fault in permanent magnet synchronous motors is a common issue. This study utilizes the finite element method and the Timoshenko beam element theory to develop a dynamic model of the rotor. It also establishes models for the hybrid eccentric unbalanced magnetic pull (UMP) and the bearing restoring force. It was found that the rotation frequency component in the spectrum response diagram under fault conditions appears a ‘peak’ phenomenon in the subcritical speed region. By analyzing the dynamic characteristics of the system when the permanent magnet synchronous motor rotor experiences radial eccentricity fault, it is observed that the UMP leads to an increase in the bearing contact load. The system’s spectrum response is primarily influenced by the rotor rotation frequency and frequency multiplication components due to the coupling of UMP and bearing restoring force. This paper investigates the influence of permanent magnet residual magnetism on the vibration characteristics associated with rotor eccentric faults. The findings indicate that the magnitude of the residual magnetism is positively correlated with the amplitude of frequency doubling. Additionally, this study includes experimental research that corroborates the accuracy of the theoretical model. The conclusions presented in this article offer a theoretical foundation for the detection and diagnosis of radial eccentricity faults in permanent magnet synchronous motor rotors.
Origami-inspired triboelectric sensor (TES) for shape detection of underwater thruster
Authors: Pan Xueting , Li Cao , Yang Fei , Zhao Yong , Yue Honghao , Geng Zhongtai
Published: December 2024

The shape change of the thruster can reflect its motion state, and motion control of the thruster can be carried out more effectively by monitoring its motion state. The unique structure of the origami thruster increases the difficulty of sensor configuration, which significantly limits the application of origami structures (ORSs) in the thruster field. To solve the above problems, we propose a triboelectric sensor (TES) based on a triboelectric nanogenerator, which can be perfectly matched with an ORS and used to monitor the shape of an underwater thruster. The TES proposed can sense the folding angle of the structural unit of the origami thruster and then monitor its shape. The effects of different friction layer materials, different friction layer thicknesses, and multiple pairs of friction subs in series/parallel were analyzed on TES output characteristics. A scheme with thin copper sheets as electrodes, the polyethylene terephthalate resin as dielectric layers, and four pairs of friction pairs connected in parallel were selected for sensor performance testing. Finally, the origami thruster and TES are assembled for underwater testing. The shape of the origami thruster was monitored using the TES. The dihedral angle that TES can detect ranges from 22.5° to 63.5°, corresponding to the radius variation of the thruster ranging to 44.4%. The maximum error between the output result and the measured value was 4.19%, which proves that TES has a good detection effect on the shape change of the thruster and has a broad application prospect in robot motion monitoring.
Gold coating reduces thermal conductivity of oriented polypropylene fibers
Authors: Zhou Yupeng , Yin Hao , Hu Xue , Zhao Gutian , Yang Juekuan
Published: December 2024

Self-heating methods are widely used in thermal conductivity measurements of polymer fibers. In these methods, a thin metallic film needs to be coated on the fibers if the fibers are electrical insulators. In this paper, the thermal conductivities of oriented polypropylene (PP) fiber samples before and after gold coating were measured. The results show that the gold-coating process can reduce the thermal conductivity of oriented PP fibers by about 50%. Therefore, the self-heating methods are not appropriate for thermal conductivity measurements of insulative polymers. This finding is important to the research of thermal conductive polymers.
Traceability uncertainty evaluation of electronic transformer calibrators based on DREAM-integrating Sparrow Search
Authors: Chen Mianzhou , Li Hongbin , Zhang Chuanji , Du Yufei
Published: December 2024

Accurate traceability uncertainty evaluation guarantees the effectiveness and reliability of electronic transformer calibrators. The traceability uncertainty evaluation of electronic transformer calibrators using the guide to uncertainty in measurement (GUM) method ignores the type and width differences of the probability distribution of the inputs as well as the correlation among the inputs. To solve this problem, which impacts the accuracy and reliability of the evaluation results, a Bayesian uncertainty evaluation model based on DREAM-integrating Sparrow Search (SDREAM) is proposed. The proposed model organically combines Bayesian statistical inference with the Monte Carlo method (MCM) sampling idea, imitating the posterior probability density of multidimensional parameters with the multi-chain sampling of Markov chain Monte Carlo. Based on the multi-chain sampling of DREAM, the proposed model integrates the idea of sparrow finder search, improves the mutation strategy, and dynamically updates the crossover probability factor to balance the global and local search capabilities, which enhances the search efficiency and accuracy of the posterior probability density space of the indirectly measured multidimensional parameters. Moreover, a multidimensional posterior probability density sampling simulation example is presented based on the traceability of the digital differential method of electronic transformer calibrators. The simulation results show that SDREAM outperforms DREAM. The proposed model is also used to evaluate the traceability uncertainty of the digital differential method of electronic transformer calibrators. The obtained results are consistent with the results of the GUM and MCM methods but exhibit higher stability and good robustness.
Assessing the precision and accuracy of cloud removal and satellite angle correction techniques for SST retrieval in the South Sea with MODIS
Authors: Fan Bowen , Qin Zhiliang , Li Hui
Published: December 2024

Cloud cover and satellite angle significantly impact sea surface temperature (SST) retrievals from remote sensing imagery, yet traditional methods often overlook these factors. This study takes Moderate Resolution Imaging Spectroradiometer remote sensing imagery from the northern South China Sea in winter as a case study to investigate the effects of cloud cover and satellite angle on SST retrieval. By employing adaptive cloud detection, cloud masking, and angle correction techniques, a SST retrieval model based on the split-window algorithm was established and compared with microwave and in-situ data. The research results indicate that: (1) The established cloud removal and satellite angle correction model for SST retrieval demonstrates high precision and accuracy, with an average error of less than 0.5 °C. (2) Combination a (cloud removal + angle correction), Combination b (non-cloud removal + angle correction), and Combination c (non-cloud removal+ non-angle correction) have an average error of −0.916 °C, −0.311 °C, −1.047 °C respectively. It is evident that the inversion results of the proposed model (Combination a) exhibit a higher level of agreement with the measured data compared to t Combination b and Combination c. (3) The average error of the microwave inversion data (combination x) is 0.560 °C; Furthermore, combination x shows a different temperature curve trend compared to the measured data, whereas combination a aligns more closely with the temperature curve trend of the measured data. Accurate retrieval of SST is of great significance for understanding large-scale oceanic circulation systems, boundary currents, eddies, and ocean currents, as well as studying seasonal and interannual variations in marine ecosystems.
Effects of viscous damping on the bandgaps of multi-frequency periodic structure
Authors: Wang Jun , Li Guizhong , Huang Wenhao , Zhang Binbin
Published: December 2024

Locally resonant elastic metamaterials (EMMs) have the ability to mitigate or even completely suppress the propagation of vibration within bandgaps, holding promising potential in the field of vibration control. However, achieving broadband vibration suppression remains a significant challenge for EMMs based on single resonance. To address this issue, we propose a scheme employing multiple resonators and introduce a damping mechanism to attenuate vibrations outside the bandgap frequency domain, aiming at wideband vibration control. The effectiveness of this approach is verified through a combination of analytical modeling and numerical analysis. By adjusting the damping characteristics of the internal resonators, we successfully extend the frequency range of vibration attenuation beyond the limitations of traditional designs. Using a mass–spring model coupled with a Kelvin–Voigt type oscillator damping model, an analytical framework is established for the dissipative multi-resonator unit and validated against published experimental data. Further parametric studies reveal the influence of additional loss coefficients on vibration attenuation performance. By optimizing the damping coefficients, the vibration attenuations are enhanced within 0–7500 Hz while maintaining a high attenuation rate near the resonance frequencies. This research provides new theoretical insights and practical guidance for the design and application of dissipative multi-resonator EMMs, holding promise for advancing broadband vibration and elastic wave suppression technologies.
A double neural network model predictive control method for series elastic actuator’s motor thermal protection
Authors: Zhang Anlong , Lin Zhiyun , Wang Bo , Han Zhimin
Published: December 2024

Traditional motor protection methods are conservative, neglecting actual thermal conditions and underutilizing the motor’s performance. This paper proposes a novel double neural network model predictive control (DNMPC)-based protection method to maximize motor performance. First, we analyze the system’s thermal properties and propose a thermal lemma to demonstrate that solving the protection problem involves determining the maximum allowable control input boundary. Second, instead of directly measuring the motor temperature, the neural network (NN) method is proposed to establish the system’s thermal model for estimating the motor temperatures. Third, leveraging the NN model, we propose a model predictive control strategy designed to determine the maximum allowable control input boundaries, which we refer to as the neural network model predictive control (NMPC) method. Consequently, this approach has led to the development of an advanced motor protection system. To further reduce the computational burden, we incorporate an additional NN to directly approximate the NMPC controller, thereby forming our proposed DNMPC approach. Finally, comparative experimental validation demonstrates the effectiveness and superiority of the proposed method. The results indicate that the NN model is highly accurate, eliminating the need for direct temperature measurements and enabling the prediction of future motor temperatures. Additionally, the DNMPC-based protection method significantly improves the joint’s peak torque output by 64.3

%

compared to conservative continuous current limited protection methods. The computational efficiency is also notable, with the NMPC achieving a runtime of approximately 20 ms, while the DNMPC achieves only 0.2 ms.
Improved singular spectrum decomposition method for resonance recognition of air-coupled ultrasonic signals in through-transmission steel plate detection
Authors: Li Rongxue , Yang Lijian , Zhang Jia , Lian Zheng
Published: December 2024

Air-coupled ultrasonic resonance detection is an emerging technique that eliminates the need for coupling agents in conventional ultrasonic testing and has a wide range of applications. However, this technique faces challenges, such as weak signal strength and susceptibility to noise, primarily due to the mismatch of acoustic impedance at the air–solid interface and sound attenuation in the air. This study proposed an improved signal processing method based on singular spectrum decomposition (SSD), optimizing the frequency components of each iteration using singular spectrum analysis. Additionally, a weighted Hurst exponent was introduced as a selection criterion to identify useful components and reconstruct the signal. Simulation results demonstrated the effectiveness of this method in denoising components and extracting weak resonance frequency features, especially in low signal-to-noise ratios (SNRs). Compared with conventional SSD and empirical mode decomposition, the proposed method improved the SNR by 39.4% and 301.33%. Furthermore, repeated experimental studies on steel plates with varying air lift-off distances and thicknesses confirmed that the proposed method could effectively reduce noise, thereby enabling accurate measurement of steel plate thickness.
Spatiotemporal-varying tropospheric stochastic model for GNSS meteorology enhancement
Authors: Xiao Yingchao , Zhan Xingqun , Zhai Yawei
Published: December 2024

Accurately estimating the zenith wet delay (ZWD) is critical in Global Navigation Satellite System (GNSS) meteorology. ZWD is typically modeled as a random walk process with spatiotemporal-invariant process noise in the Kalman filter using precise point positioning. However, this approach is not rigorous due to the notable geographical and seasonal variations in water vapor content. In response, we propose a spatiotemporal-varying ZWD stochastic model to improve the ZWD estimation accuracy, thereby enhancing the GNSS meteorology. First, 15 years of ZWD data are employed to derive the process noise. Next, the model is established using a trigonometric-based fitting function. Finally, hierarchical clustering is implemented for computational efficiency improvement. Experiments at 26 test stations indicate that the maximum ZWD accuracy is improved by 34.95% under dynamic mode and 22.67% under static mode. Moreover, the maximum data availability of GNSS meteorology is improved by 10.56% and 4.55% under dynamic and static modes, respectively.
Prediction of wheel-rail force and vehicle safety index using genetic algorithm–based backpropagation neural network with physics-based inversion model
Authors: Zhang Yanyan , Yang Xinwen , Sun Zhiang , Mao Ke , Xiang Kaiwen , Ye Zi , Qu Yingtao
Published: December 2024

Wheel-rail force is a crucial indicator for vehicle safety and stability in wheel-rail interactions. To predict and display the continuous wheel-rail force and vehicle safety index efficiently and in real time, a multiple-input, multiple-output backpropagation neural network (BPNN) for wheel-rail force and vehicle safety index prediction based on a physical inversion model is developed. The physics-based inversion model calculates wheel-rail forces by using the wheelset inertia force, the primary suspension displacement, and the Nadal derailment criterion. Vehicle safety indices such as wheel derailment coefficient and wheel unloading rate are estimated using the known wheel-rail forces. This physics-based model suggests a nonlinear inversion mapping from the input to the output for constructing the BPNN. Meanwhile, it is a low-cost method to collect training and test samples, and is also used as a training tool for the neural network. A genetic algorithm (GA) is introduced to optimize the initial weight and bias in the BPNN to enhance the network converge speed and prediction performance. The physics-based model is implemented in the field experimental tests conducted on a subway line in China to construct the sampled data. After the BPNN and GA-optimized BPNN (GA-BPNN) are trained, tested, and tuned based on the experimental data, it proves that the BPNN can predict the desired output reliably and that the GA-BPNN performs more accurately than BPNN. The wheel-rail force and vehicle safety index prediction model proposed in this paper can contribute to the development of vehicle intelligent diagnosis and fault warning platforms in the future.
Real-time undifferenced precision time transfer of multi-GNSS and multi-frequency
Authors: Xu Wei , Yan Chao , Zhang Pengfei , Chen Jian , Qiu Duobing , Liang Lei , Song Jia , Zhao Lewen , Tao Jing
Published: December 2024

Currently, the four major Global Navigation Satellite Systems (GNSS) are capable of supporting multi-frequency signals, and Real-time (RT) State Space Representation (SSR) correction products have been enriched and improved. Multi-GNSS, multi-frequency observations and multiple satellite RT SSR correction products present new opportunities to implement precise RT time transfer. This study extends the traditional post-processing dual-frequency undifferenced (UD) Precise Point Positioning (PPP) time transfer to RT multi-frequency scenarios, establishes models for dual-frequency, triple-frequency, quad-frequency and penta-frequency multi-GNSS PPP time transfer, and evaluates the product availability, orbit accuracy and clock offset accuracy of RT SSR products from BKG, CNE, DLR, ESA, GFZ, GMV, WHU, and IGS. A multi-frequency and multi-GNSS RT PPP time transfer experiment was conducted by selecting data from four stations, BRUX, PTBB, ONSA and SPT0, with precise atomic clocks mounted for one week. The accuracy of various SSR products in RT PPP time transfer was compared, and the performance of BDS/Galileo combination dual-frequency to penta-frequency RT UD PPP time transfer was evaluated. The experimental results show that the standard deviation and frequency stability difference of RT PPP time transfer among each SSR product is relatively small, especially after combining multi-systems. The frequency stability tends to be entirely consistent. In general, the WHU, GFZ, GMV, and WHU SSR products offer notable advantages in terms of accuracy and frequency stability for GPS, GLONASS, Galileo, and BDS RT PPP time transfer, respectively. Multi-GNSS and multi-frequency signals have both enhanced RT PPP time transfer performance, with a particularly noticeable improvement in terms of accuracy and short-term frequency stability. The effect of multi-GNSS on RT PPP time transfer is more pronounced than that of multi-frequency alone. Considering the higher costs associated with multi-frequency GNSS receivers, prioritizing multi-GNSS for RT PPP time transfer is recommended.
Research on the mechanism of emissivity enhancement by the structure of the blackbody cavity
Authors: Zhou Jingjing , Song Jian , Guo Guorui , Xu Chunyuan , Xu Xin , Hao Xiaopeng
Published: December 2024

The spaceborne blackbody with high emissivity can provide accurate infrared radiation to calibrate infrared payloads. To meet the need for improving the accuracy of infrared value traceability, this paper investigates the mechanism of enhancing emissivity through the structure of the blackbody cavity. The directional emissivity calculation based on Monte Carlo optical simulation was carried out. The normal and directional emissivity distributions of cylindrical cavity blackbody and trap-cavity blackbody (TCB) were simulated and compared. The emissivity of the 8–14 μm band was measured. The simulation and experimental results indicate that TCBs demonstrate better central normal emissivity and cylindrical cavity blackbodies exhibit higher variations in emissivity. The mechanism of high emissivity for two types of blackbodies by controlling the number and direction of light reflection is analyzed. Furthermore, we propose a blackbody design method with high-level emissivity by investigating the influence of cavity structure and reflection characteristics on blackbody emissivity, which has a high normal emissivity of 0.9997 and small variations in directional emissivity of 0.0002. The study provides theoretical and experimental support for the development of large aperture high emissivity spaceborne blackbody.
Air-stable, aluminium oxide encapsulated graphene phototransistors
Authors: Rojas Castiglione Tomás , Pucher Thomas , Dockx Kaj , Aburto Contreras Guillermo , Sanz Biava Diego , Briceño Elchiver Benjamín , Buscema Michele , Castellanos-Gomez Andres , van der Zant Herre , Dulić Diana
Published: December 2024

Graphene has garnered significant interest in optoelectronics due to its unique properties, including broad wavelength absorption and high mobility. However, its weak stability in ambient conditions requires encapsulation for practical applications. In this study, we investigate graphene CVD-grown field-effect transistors fabricated on

Si

/

SiO
2

wafers, encapsulated with aluminum oxide (

Al
2

O
3

) of different thicknesses. We measure and analyze their optoelectronic response across wavelengths from near-ultraviolet to near-infrared. We find that, while having a negligible role in the photogating process, the

Al
2

O
3

layer leads to stable and reproducible transferring curves operating in ambient conditions for over a month, with stable responsivities up to 1.5

A W

−
1

at the shortest wavelength. Moreover, the transferring curves are stable at elevated temperatures up to 107

°

C

. We also show that the sample performance can be tuned by changing the thickness of the

Si

O
2

and

Al
2

O
3

layer which brings further perspectives in developing robust sample technologies, especially in the ultraviolet region where the responsivity increases. Aluminum oxide encapsulated graphene-based photodetectors can thus be interesting for applications in air and at elevated temperatures.
Dexamethasone-loaded fibroin nanoparticles promote retinal reattachment in rats by regulating the Th17/Treg balance
Authors: Han Linfeng , Li Xiaomeng , Ke Genjie , Dong Kai , Wang Guoping , Sheng Yonghong , Tao Liming
Published: December 2024

Retinal detachment (RD) is a common acute blinding eye disease, and dexamethasone (DEX), an adrenocorticosteroid, shows protective effects against RD. However, its poor water solubility and low bioavailability limit its effectiveness. To address this, we developed SF@DEX nanomaterials and investigated their therapeutic potential and mechanisms in RD. The nanomaterials were successfully synthesized and characterized, achieving 90% encapsulation efficiency and releasing 60% of DEX within 12 h. In vitro, phagocytosis was measured by flow cytometry, and enzyme-linked immunosorbent assay determined interleukin-17 (IL-17) and interleukin-10 (IL-10) levels. A rat RD model was established surgically, followed by oral administration of silk fibroin (SF), SF@DEX, and DEX. Polymerase chain reaction (PCR) assessed IL-17A and forkhead box P3 (FOXP3) expression, while Western blot analysed transforming growth factor-β1 (TGF-β1), IL-10, IL-17A, and FOXP3 levels. Apoptosis of retinal ganglion cells was evaluated using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and confocal microscopy detected colocalization of IL-17A and FOXP3. SF@DEX treatment significantly reduced Th17 cells and IL-17A while increasing Tregs, FOXP3, TGF-β1, and IL-10 levels. The severity of RD in rats was notably alleviated by SF@DEX, demonstrating its anti-inflammatory effects through modulation of the Th17/Treg immune balance. These results highlight SF@DEX as a promising nano-based therapy for RD.
Breather and rogue-wave solutions of the semi-discrete and continuous nonlinear Schrödinger equations on theta-function backgrounds
Authors: Li Ruomeng , Geng Jingru , Geng Xianguo
Published: December 2024

A new method to construct localized-wave solutions of the semi-discrete and continuous nonlinear Schrödinger (sd-NLS) equations on theta-function backgrounds simultaneously is developed. (1) The semi-discrete NLS equation is rewritten as the difference-quotient NLS equation so that the continuum limits are easy to calculate. (2) By rewriting the difference-quotient equation in the form of Hiorta bilinear equations, a theta-function seed solution for the difference-quotient NLS equation is derived, in which the theta-function is so general that both

dn

- and

cn

-type seed solutions are its special reductions. (3) Using the Baker–Akhiezer functions on algebraic curves, a systematic method for solving continuous and semi-discrete spectral problems with theta-function potentials is given, from which rogue-wave and breather solutions of the sd-NLS equation on theta-function backgrounds are constructed with the aid of the derived Darboux transformations. (4) By investigating the exact solutions of the difference-quotient NLS equation, it is found that the sd-NLS equation has extremely high rogue waves (

>
600

times of the background wave), which is not observed in the NLS equation. This method has universality and can be applied to other semi-discrete integrable equations.
Reply to Comments on ‘Modeling for predicting survival fraction of cells after ultra-high dose rate irradiation’
Authors: Shiraishi Yuta , Matsuya Yusuke , Fukunaga Hisanori
Published: December 2024

Liew and Mairani (2024 Phys. Med. Biol. 69 248001) commented on our previous reply to comments on our paper, ‘Modeling for predicting survival fraction of cells after ultra-high dose rate irradiation’. We appreciate their comments on the choice of experimental data on DNA damage for cell survival and agree that the estimate of the dose-response curve on cell survival depends on the selection of DNA damage data. As an additional benchmark test, we compared the relative biological effectiveness (RBE) predicted using the recommended DNA damage data measured in normoxia with those reported in our original paper, and confirmed that the difference in RBE was less than 8%. Although our model allows for the estimation of cell survival and RBE under ultra-high dose rate (UHDR) irradiation, we highlight that a further accumulation of experimental data on DNA damage under UHDR irradiation is necessary for the further development of biophysical models concerning the mechanistical estimation of biological effects.
The role of effective dose in medicine now and into the future
Authors: Martin Colin J , Abuhaimed Abdullah
Published: December 2024

Effective dose was created as a radiological protection dose quantity linked to risk to enable planning of radiological protection for the control of exposure. Its application and usage has evolved from occupational and public exposure during work with radiation sources to medicine and applications in patient dosimetry. Effective dose is the sum of doses to organs and tissues within the body weighted according to their sensitivity to radiation for induction of stochastic effects determined from epidemiological studies of exposed populations. It is based on radiation risks averaged over the population and formulated using reference phantoms. Effective dose has been adopted by the medical community for application to patients and has been instrumental in raising awareness of doses from medical imaging. However, although effective dose can be used for comparison of doses from different medical procedures, it is not designed for application to individual patients. The reasons being that organ doses vary with the stature of the patient and the radiation risks depend on the age and sex of the patient. Moves to more personalised medicine have created a desire for a more individualised approach to patient dosimetry, although support for this progression is not universal. This paper traces the evolution of effective dose and its applications. It reflects on how well effective dose provides a measure of risk for individual patients and examines ways in which a more personalised approach might be developed with reference to computed tomography. It considers differences in dose relating to the sizes of patients and looks at variations in risks of cancer incidence within a population with an age distribution typical of patients and examines how this relates to the risk profile. Possible options for improving the individualisation of dosimetry are discussed.
Low dose contrast enhancement of biodegradable low-density stents by an approach balancing radiopaque coatings and beam filtration
Authors: Ravanbakhsh Samira , Zekraoui Souheib , Lescot Theophraste , Bazalova-Carter Magdalena , Mantovani Diego , Fortin Marc-André
Published: December 2024

Objective. Biodegradable cardiovascular stents made of thin, low atomic number metals (e.g. Zn, Mg, Fe) are now approved for clinical use. However, poor contrast under x-ray imaging leads to longer surgical times, high patient exposure, and sometimes stent misplacement. This study aimed at enhancing the visibility of low-Z metal stents under x-ray imaging, by combining high-Z metal coatings and beam filtration. Approach. Photon energy spectra from W-anode x-ray beams operated at 80 and 120 kVp, were generated by the SpekCalc and BEAMnrc softwares. The contrast produced by Fe stent struts (50–10 μm W coatings), as well as dose and air kerma values (by BEAMnrc), were simulated. Several types of beam hardening filters (Sn: 0.1, 0.2 mm; Cu: 0.2, 0.7 mm) were also applied. Then, Fe foils (50 µm) with W coatings (2–3 µm-thick) were fabricated by magnetosputtering. These samples were x-ray visualized, for quantification of contrast between W-coated and uncoated Fe samples. Fe struts (50 µm) were also coated with W (3.8 ± 0.2 µm), and stent-like objects were x-ray visualized. Main results. Fe samples attenuate 6.4% (120 kVp) and 10.1% (80 kVp) spectra photons, and 25% and 34.5% for W-coated Fe samples (SpekCalc). BEAMnrc calculations revealed the highest contrast improvement in a 120 kVp beam (36.4%, and 38.5%) for W-coated and uncoated Fe samples with Sn (0.2 mm), and Cu + Sn (0.2 + 0.2 mm) filters. Experimentally, the highest contrasts between Fe and W–Fe foils, were obtained with 0.2 mm Sn (77 ± 7% contrast increase at 80 kV). The dose was also strongly reduced (70% and 75%, for 80 and 120 kVp beams). Finally, for 3D Fe stents visualized at 80 kVp, the highest CNR and CNRD values were achieved with 0.1 mm Sn (18.5 × and 20.1 mGy−1; compared to 15.0 × and 12.0 mGy−1 in no-filter condition). Significance. The contrast of Fe-based stents in x-ray imaging is improved by addition of a thin layer of W and beam filtration with Sn. The precision and rapidity of biodegradable stents implantation would be improved thereby, as well as the dose to patients.
Diocotron modes in pure electron plasmas in the APEX levitating dipole trap
Authors: Deller A , Bayer V C , Steinbrunner P , Card A , Danielson J R , Stoneking M R , Stenson E V
Published: December 2024

Observations of persistent toroidal modes in dipole-trapped pure electron plasmas are presented. Non-neutral electron plasmas were confined by the poloidal magnetic field of the APEX (A Positron Electron eXperiment) levitating dipole trap. The negative bias of the electron emitter was gated to control the filling time. Large amplitude, narrow-band oscillations were consistently observed in wall probe measurements after the fill. The oscillatory image-charge currents induced by the trapped electron plasma typically persisted for many seconds with fundamental frequencies, f
0 = 50 to 500 kHz, that scale with the

E
→

×

B
→

drift velocity. We attribute this feature to the dipole-equivalent of the diocotron mode that is commonly observed in non-neutral plasmas in linear traps.
Assessment of the JET ICRH system performance since 2000
Authors: Monakhov I , Jacquet P , Dumortier P , Durodié F , Lerche E , Lobel R , Mayoral M-L , Noble C , Roberts J , Sheikh H
Published: December 2024

The paper provides an assessment of the ion-cyclotron resonance heating (ICRH) system performance on JET since the year 2000. The vast amount of collected data offer an insight into the historical challenges and trends in the ICRH system performance encompassing the transition from carbon (JET-C) to beryllium & tungsten ITER-like wall (JET-ILW) operations, the deuterium–tritium experiments (DTE2 & DTE3) and introduction of new RF antenna & matching systems. The best achieved operational parameters are reported and statistics on the RF plant reliability and performance is analysed. Antenna-plasma coupling is identified as the dominant factor critical to all the aspects of the ICRH system behaviour; parametric dependencies of coupling resistance on plasma parameters and the RF plant settings are discussed and the key role of local electron concentration profiles close to the antennas is highlighted. Following confident antenna performance at high RF voltages over the recent decade, observations are presented suggesting improved electrical strength of the RF vacuum components after the JET-C to JET-ILW transition; this is tentatively attributed to the reduction of dust levels in the JET vessel. Statistics on application rate and typical origins of the RF amplifier failures and protection power limits is presented indicating that the amplifier issues noticeably affected the high-power ICRH operations. Performance comparison is provided for different RF antenna & matching systems installed at JET since 2000 including the original system, two load-tolerant systems based on the 3 dB hybrid and external conjugate-T power-splitters, and the ITER-like antenna. The paper could be of interest both as a summary of technical challenges, constraints and achievements related to the ICRH application on JET and as a reference for design and operations of high-power RF systems in future fusion devices.
Investigating the impact of intermediate-mode perturbations on diagnosing plasma conditions in DT cryogenic implosions via synthetic x-ray Thomson scattering
Authors: Poole H , Cao D , Epstein R , Golovkin I , Goncharov V N , Hu S X , Kasim M , Vinko S M , Walton T , Regan S P , Gregori G
Published: December 2024

The pursuit of inertial confinement fusion ignition target designs requires precise experimental validation of the conditions within imploding capsules, in particular the density and temperature of the compressed shell. Previous work has identified x-ray Thomson scattering (XRTS) as a viable diagnostic tool for inferring the in-flight compressed deuterium-tritium shell conditions during capsule implosions (Poole et al 2022 Phys. Plasmas
29 072703). However, this study focused on one-dimensional simulations, which do not account for the growth of hydrodynamic instabilities. In this work, two-dimensional DRACO simulations incorporating intermediate-mode perturbations up to Legendre mode

ℓ
=
50

were used to generate synthetic XRTS spectra with the SPECT3D code. The analysis employed Markov-Chain Monte Carlo techniques to infer plasma conditions from these spectra. The results demonstrate that the XRTS diagnostic platform can effectively discern the in-flight compressed shell conditions for targets with varying adiabats, even in the presence of intermediate-mode perturbations. This work underscores the potential of XRTS for realistic inertial confinement fusion experiments, providing a robust method for probing the complex dynamics of fusion implosions.
A weighted matching scheme of magnetic coil design for FRC shaping control
Authors: Qu Zitong , Zhu Ping , Chen Zhipeng , Li Haolong , Liu Jiaxing
Published: December 2024

The two-dimensional (2D) separatrix shaping plays a crucial role in the confinement of the field-reversed configuration (FRC), and the magnetic coils serve as an effective means for its control. In this work we develop a weighted matching method to obtain an MHD equilibrium that accurately corresponds to the shape of target separatrix. By iteratively calculating the coil currents, the plasma current, and the equilibrium magnetic flux, the equilibrium separatrix progressively converges towards the desired shape. The coil currents are determined through a matching method, and the NIMEQ code is employed to compute the FRC equilibrium with a rigid rotor model of plasma distribution. This approach enables the adaption of the equilibrium separatrix into any desired shape, thus offering a potential scheme for the design and control of the 2D shaping of FRC plasma.
Operation of a lithium beam diagnostic in tritium and deuterium–tritium experiments at JET
Authors: Brix M , Gomes R , Pereira T , Anda G , Dunai D , Nedzelksi I , Petravich G , Refy D , Riddle K , Scully S , Tal B , Vécsei M , Zoletnik S ,   the JET Operations Team
Published: December 2024

A fast neutral lithium beam has been used at JET for more than 30 years to measure profiles of electron density in the pedestal and scrape off layer. The diagnostic was not designed for tritium operation. In this paper, we describe the modifications which were required to allow operation in tritium (T) and deuterium–tritium (D-T) fuelled pulses at JET in 2021 and 2023. Methods to allow remote startup and remote control of the beam were implemented. The vacuum pump and exhaust system had to be made tritium compatible. Radiation vulnerable electronics had to be removed from the torus hall. The observation system relied on regular in vessel mirror exchange. An in-vessel protection shield was installed close to the observation mirror to protect the mirror surface. Operation in T and D-T discharges, maintenance post tritium exposure, commissioning and the calibration of the diagnostic are discussed.
Broad wavenumber turbulence measurement in the same region on EAST
Authors: Sun N , Li Y D , Li P , Chen F , Geng J S , Li Y X , Sun P J , Wang S F , Hu J S
Published: December 2024

Future burning plasma in magnetic confinement fusion devices necessitates diagnostic for measuring broad wavenumber turbulence. The CO2 laser collective Thomson scattering (CO2-CTS) system on EAST is designed mainly for electron-scale turbulence measurements. In order to extend the capability to detect ion-scale turbulence, the key challenges of light separation and signal detection have been successfully addressed by the construction of the extremely-small-angle CO2-CTS (E-CTS) diagnostic. This paper employs the CO2-CTS in conjunction with the E-CTS, enabling the simultaneous monitoring of turbulence (

0.5
<

k
θ

ρ

s

<
5

) over a broader wavenumber range (k ∼ 5–30 cm−1) within the gradient region (

ρ
∼
0.4
−
0.8

). The application of E-CTS studies the characteristics of multi-scale turbulence, including turbulence correlation and dispersion relations. This advancement will significantly enrich our experimental comprehension of tokamak turbulence.