bluuebunny/crossref_metadata_2025 huggingface dataset:
Thickness-dependent thermoelectric properties of ultrathin polymer film on self-assembled monolayers
Authors: Chen Xiaomin , Jin Jiaoying , Sun Shiyuan , Xiao He , Wang Lei , Liu Danqing
Published: February 2024

Conductive polymers have attracted attention for wearable and implantable thermoelectric devices due to their lightweight, flexibility, and solubility. With the development of microsystems, thermoelectric power generation devices are trending toward miniaturization, flexibility, high integration, and lightweight thin films. Therefore, the study of the thickness of thermoelectric materials has become increasingly important. In this study, we prepared ultrathin polymer thermoelectric (TE) films with different thicknesses (14–52 nm) by modifying the substrate with self-assembled monolayers (SAMs). The thickness-dependent thermoelectric performances on SAMs are investigated. It is found that SAMs regulate the carrier concentration in polymer ultrathin TE films, and a smoother surface contributes to the improvement of carrier mobility, thus optimizing the thermoelectric performance. The maximum modulation of thermoelectric performance is observed at a film thickness of approximately 35 nm, which contains nine molecular layers.
Space-confined solid-phase growth of two-domain 1T′-ReSe2 for tunable optoelectronics
Authors: Tong Yunhao , Kong Fanyi , Zhang Lei , Hou Xinyi , Zha Zhengxian , Hao Zheng , Dai Jianxun , Sun Changsen , Song Jingfeng , Huang Huolin , Ji Chenhua , Pan Lujun , Li Dawei
Published: February 2024

Two-dimensional layered ReX2 (X = Se, S) has attracted researcher's great interest due to its unusual in-plane anisotropic optical and electrical properties and great potential in polarization-sensitive optoelectronic devices, while the clean, energy-saving, and ecological synthesis of highly crystalline ReSe2 with controlled domains remains challenging. Here, we develop a space-confined solid-phase approach for growing high-quality two-domain 1T′-ReSe2 with tunable optoelectronic properties by using pure Re powder as a Re precursor. The results show that ReSe2 can be grown at a temperature as low as 550 °C in a small-tube-assisted space-confined reactor, with its size and shape well-tailored via temperature control. A solid-phase two-domain ReSe2 growth mechanism is proposed, as evidenced by combining in situ optical monitoring, ex situ electron microscope, elemental mapping, and polarized optical imaging. Moreover, two-domain ReSe2 transistors are fabricated, which exhibit a switchable transport behavior between n-type and ambipolar character via grain boundary orientation control. This modulation phenomenon is attributed to the different doping levels between grain boundary and single domain. Furthermore, our two-domain ReSe2 photodetectors exhibit a highly gate-tunable current on–off ratio (with a maximum value of ∼8.2 × 103), a polarization-sensitive photo-response, and a high-speed response time (∼300 μs), exceeding most of the previously reported ReX2 photodetectors. Our work, thus, provides a low-consumption, energy-saving growth strategy toward high-quality, domain-controlled ReX2 for highly tunable and high-performance optoelectronics.
Modeling and experimental studies of degaussing hysteresis in near-zero magnetic shielding systems
Authors: Wang Zenghui , Li Haitao , Yang Siyi , Han Bangcheng , Yu Shicheng , Wen Tong
Published: February 2024

Near-zero magnetic shielding systems (MSSs) can provide basic experimental environments for extremely weak magnetic measurements. Reducing the internal magnetic field of MSS is the crucial element of high-sensitivity measurements, which is related to the shielding material flux. As an effective way to regulate the material remanence, degaussing reconstructs the magnetic balance with the geomagnetic field. However, previous research studies mainly focused on the optimization of material degaussing, with few considering the practical application scenarios of MSS. In this work, a numerical modeling method is proposed to realistically depict the balancing process, and the mapping relationship between the internal magnetic field of the MSS and the degaussing current is established. First, the magnetic field source analysis is carried out, and the internal magnetic field fluctuations of the MSS during degaussing are decomposed into multi-harmonic components. Then, the phase and amplitude changes of the hysteresis loop are simulated to predict the residual field. Thereafter, the effectiveness of the method is verified by a magnetic shielding cylinder. The experimental results indicate that the slight difference in material remanence has a negligible effect on the residual field. This work has potential application value in the research of degaussing technology.
A semi-theoretical method for determining the permeability tensor of fractured rock masses in three-dimensional space
Authors: Wang Xiaohong , Zheng Jun , Sun Hongyue , Lü Qing , Ge Qi , Tan Shengkui
Published: February 2024

The permeability tensor is a critical parameter for analyzing the hydraulic behavior of anisotropic permeability in fractured rock masses. However, determining this tensor for three-dimensional (3D) fractured rock masses has proven to be challenging and resource-intensive. Both field tests, requiring numerous costly in situ tests, and numerical experiments, hindered by complex discrete fracture networks with a high fracture density, present difficulties in obtaining accurate results. In response, this study proposes a semi-theoretical method for determining the permeability tensor of 3D fractured rock masses, significantly reducing labor and economic costs. The proposed method focuses on establishing the theoretical relationship of directional permeabilities in a 3D space, with emphasis on the properties of the permeability tensor and the influence of fractures' geometry on the flow rate. To facilitate the construction of the method, anisotropic ellipse and ellipsoid are introduced, providing a description of permeability anisotropy. With this innovative approach, engineers can calculate the permeability tensor even when only one value of permeability is available along any flow direction. The utilization of the anisotropic ellipse and ellipsoid concepts helps simplify the determination process. Through numerical experiments, the method is validated and its accuracy demonstrated, making it a valuable tool for analyzing the hydraulic behavior of 3D fractured rock masses.
Does the immune stimulant Amplimune® modulate humoral and cytokine responses to commercial bovine respiratory disease vaccines in cattle?
Authors: Alexander A. L. , Doyle E. K. , Ingham A. B. , Colditz I. G. , Andronicos N. M. , Hine B. C. , Mahony T. J.
Published: February 2024

Context Feedlot entry can be a period of stress for cattle due to transportation, altered diets and other influences. Stress can suppress host defence mechanisms. Innate immune stimulants, such as mycobacterial cell-wall fractions, attract attention for the primary objective of enhancing non-specific immune resistance of cattle against microbial diseases during periods of stress-induced susceptibility. These stimulants are also recognised for their capacity to modify responses of the adaptive immune system to vaccines. Aims This study aims to evaluate the potential for mycobacterial cell-wall fractions in Amplimune® to modify adaptive immune responses to the commercial vaccines Rhinogard® (modified live bovine alphaherpesvirus-1 (BoHV-1)) and Bovilis MH + IBR® (inactivated Mannheimia haemolytica and BoHV-1) in yearling cattle during simulated feedlot induction. Methods Fifty-four mixed-sex Angus yearling cattle were transported for 6 h on Day −1 and on Day 0. The cattle were assigned to the following six treatment groups (n = 9/group): Rhinogard plus 2 mL Amplimune, Rhinogard plus 5 mL Amplimune, Bovilis MH + IBR plus 2 mL Amplimune, Bovilis MH + IBR plus 5 mL Amplimune, Rhinogard plus 5 mL saline, and Bovilis MH + IBR plus 5 mL saline. Blood and nasal secretions were sampled at various time points following treatment and antigen-specific antibody (immunoglobulin G) responses to components of the vaccines were assessed. Interferon-γ production by peripheral blood mononuclear cells in response to BoHV-1, Concanavalin A or media only were assessed. Key results No adverse clinical reactions were observed to administration of Amplimune and vaccines. A systemic antibody response to vaccination was observed for the Bovilis MH + IBR vaccine. Vaccine-specific antibody and cytokine responses were not modified by Amplimune. Conclusions Amplimune can be administered at the same time as Rhinogard or Bovilis MH + IBR vaccines, without undesirable effects on specific immune responses to vaccination. Implications The primary interest in using Amplimune is to potentiate non-specific immune defences as an alternative to antibiotics for the prevention and/or treatment of microbial diseases such as bovine respiratory disease in production animals. In view of its adjuvant-like activities, administration of Amplimune might also confer beneficial or detrimental effects on antigen-specific responses of the adaptive immune system to contemporaneous vaccination.
Trajectory of a golf ball on a sloping green
Authors: Cross Rod
Published: February 2024

Calculations are presented on the trajectory of a golf ball that rolls across the inclined surface of a golf green. The ball follows a curved path and comes to a stop at a point displaced at an angle to the initial launch direction. It is shown that the displaced angle is independent of the launch speed but depends on the launch angle and the ratio of the incline angle to the coefficient of rolling friction. The stopping distance is proportional to the launch speed squared. A simple experiment is described to check the calculations.
The initial trajectory of a ball released from uniform circular motion
Authors: Batista Milan
Published: February 2024

This short paper presents a simple analytical model for the abrupt termination of circular motion, as discussed in the ‘The Most Mind-Blowing Aspect of Circular Motion’. The model confirms that when a string is released, a ball at the far end of the string continues to move in a near-circular motion for a short time.
A structured L-BFGS method and its application to inverse problems
Authors: Mannel Florian , Om Aggrawal Hari , Modersitzki Jan
Published: February 2024

Many inverse problems are phrased as optimization problems in which the objective function is the sum of a data-fidelity term and a regularization. Often, the Hessian of the fidelity term is computationally unavailable while the Hessian of the regularizer allows for cheap matrix-vector products. In this paper, we study an L-BFGS method that takes advantage of this structure. We show that the method converges globally without convexity assumptions and that the convergence is linear under a Kurdyka–Łojasiewicz-type inequality. In addition, we prove linear convergence to cluster points near which the objective function is strongly convex. To the best of our knowledge, this is the first time that linear convergence of an L-BFGS method is established in a non-convex setting. The convergence analysis is carried out in infinite dimensional Hilbert space, which is appropriate for inverse problems but has not been done before. Numerical results show that the new method outperforms other structured L-BFGS methods and classical L-BFGS on non-convex real-life problems from medical image registration. It also compares favorably with classical L-BFGS on ill-conditioned quadratic model problems. An implementation of the method is freely available.
Extrinsic calibration for large FOV based on inverse depth parameterized bundle adjustment
Authors: Zhang Shuiqiang , Yang Da , Gong Haiyang , Xu Zikang , Su Zhilong , Zhang Dongsheng
Published: February 2024

To overcome the reliance on high-precision calibration plates in camera calibration, this paper proposes an extrinsic calibration method suitable for three-dimensional digital image correlation (3D-DIC) in large field of view (FOV). The method combines image feature algorithms with DIC techniques to extract matching point pairs (MPPs) from the left and right images of binocular cameras. These MPPs are then homogenized within the FOV. Next, initial values of the extrinsic parameters are solved based on epipolar constraint theory. Finally, the calibration parameters are nonlinearly optimized using the bundle adjustment method. To achieve stable and reliable numerical optimization in large FOV applications, the calibration control points (CCPs)’ spatial coordinates are represented using inverse depth parameterization. In scenarios where there might be a lack of sufficient CCPs, speckle patterns are artificially introduced to supplement the scene features. However, there is a lack of reliable experimental basis on how to add CCPs within the FOV. Therefore, through simulations, the factors affecting calibration accuracy are analyzed to guide the actual calibration process. The proposed method’s reliability and accuracy in large FOV 3D measurement are verified through experiments.
Ultrasonic penetration method for weld root crack in orthotropic steel decks: differentiation and quantitative recognition
Authors: Xia Junyuan , Yuanzhou Zhiyuan , Ji Bohai , Chen Guorong
Published: February 2024

Weld root crack represents a significant concern in terms of fatigue on orthotropic steel decks (OSDs). This study presents a crack detection method based on ultrasonic penetration signals, to effectively distinguish and quantify cracks in decks. Firstly, based on the principles of sound diffusion and the structural characteristics of OSDs, the parameters were established. Then, the propagation mechanism of ultrasonic waves in decks containing cracks was investigated by finite element analysis. The variations in received signal intensity caused by root-deck and root-weld crack parameters were analyzed and the methods for distinguishing between crack types and determining characteristics were proposed. Finally, experimental tests were conducted on weld root cracks to validate the feasibility of the detection method. The research findings demonstrate that the selected detection parameters adequately meet the requirements for crack detection. By utilizing fitting functions between the transmission signals from two sets of detection parameters and the projected crack length, the method achieves accurate identification of crack length and angle, with an error rate of less than 10%.
A novel performance degradation assessment method for rotating machinery based on the fault information and the dynamic simulation
Authors: Zhang Jianqun , Zhang Qing , Qin Xianrong , Sun Yuantao
Published: February 2024

The performance degradation assessment (PDA) of key components such as gears and rolling bearings is the core technology of prognostics and health management for rotating machinery. Most existing PDA methods may have two deficiencies: (1) the assessment indicator constructed does not consider capturing fault characteristics directly; (2) feature selection is generally based on the measured data of different fault levels, which is difficult to obtain in actual processes; moreover, the selection results lack universality and are difficult to extend to other equipment. To address these issues, this paper proposes a novel PDA method based on fault information and dynamic simulation. First, anomaly detection is performed using four well-known indicators in combination with Mahalanobis distance. Secondly, fault identification is performed using envelope spectrum analysis on anomaly signals to determine the fault type, e.g. gear fault or outer race fault. Thirdly, based on the fault type information, the candidate feature set including fault-domain indicators is selected based on the established dynamic simulation signals to obtain a preliminary assessment vector for the first stage. The stability of the fault domain indicators which capture fault characteristics directly is tested through actual measured normal data. It is used as the second stage of selecting to obtain the assessment vector. Finally, the PDA indicator is calculated based on the assessment vector and Mahalanobis distance. Four experiment case studies demonstrate the proposed PDA method can effectively isolate faults with different defect sizes as well as track the whole performance degradation. The above analysis indicates that the proposed PDA method is expected to be used for the actual rotating machinery.
Prediction of electrical properties of GAAFET based on integrated learning model
Authors: Zhang Xuyan , Chen Siyu , Wang Shulong , Li Jiarui , Chen Dongliang , Li Yuhang , Ma Lan , Chen Shupeng , Liu Hongxia , Lv YuanJie , Xue JunShuai
Published: February 2024

As device feature sizes continue to decrease and fin field effect transistors reach their physical limits, gate all around field effect transistors (GAAFETs) have emerged with larger gate control areas and stackable characteristics for better suppression of second-order effects such as short-channel effects due to their gate encircling characteristics. Traditional methods for studying the electrical characteristics of devices are mostly based on the technology computer-aided design. Still, it is not conducive to developing new devices due to its time-consuming and inefficient drawbacks. Deep learning (DL) and machine learning (ML) have been well-used in recent years in many fields. In this paper, we propose an integrated learning model that integrates the advantages of DL and ML to solve many problems in traditional methods. This integrated learning model predicts the direct current characteristics, capacitance characteristics, and electrical parameters of GAAFET better than those predicted by DL or ML methods alone, with a linear regression factor (R
2) greater than 0.99 and very small root mean square error. The proposed integrated learning model achieves fast and accurate prediction of GAAFET electrical characteristics, which provides a new idea for device and circuit simulation and characteristics prediction in microelectronics.
In-plane anisotropic two-dimensional materials for twistronics
Authors: Kim Hangyel , Kim Changheon , Jung Yeonwoong , Kim Namwon , Son Jangyup , Lee Gwan-Hyoung
Published: February 2024

In-plane anisotropic two-dimensional (2D) materials exhibit in-plane orientation-dependent properties. The anisotropic unit cell causes these materials to show lower symmetry but more diverse physical properties than in-plane isotropic 2D materials. In addition, the artificial stacking of in-plane anisotropic 2D materials can generate new phenomena that cannot be achieved in in-plane isotropic 2D materials. In this perspective we provide an overview of representative in-plane anisotropic 2D materials and their properties, such as black phosphorus, group IV monochalcogenides, group VI transition metal dichalcogenides with 1T′ and Td phases, and rhenium dichalcogenides. In addition, we discuss recent theoretical and experimental investigations of twistronics using in-plane anisotropic 2D materials. Both in-plane anisotropic 2D materials and their twistronics hold considerable potential for advancing the field of 2D materials, particularly in the context of orientation-dependent optoelectronic devices.
Efficient degradation of organics by ultrasonic piezoelectric effect on CuO-BTO/AFC composite
Authors: Feng Haoyang , Zhang Zhi , Deng Hongxiang , Li Sean , Zu Xiaotao , Mei Zongwei
Published: February 2024

The recombination of photoexcited electron–hole pairs greatly limits the degradation performance of photocatalysts. Ultrasonic cavitation and internal electric field induced by the piezoelectric effect are helpful for the separation of electron–hole pairs and degradation efficiency. The activated foam carbon (AFC) owing to its high surface area is often used as the substrate to grow catalysts to provide more reactive active sites. In this work, CuO@BaTiO3 (CuO@BTO) heterostructure is prepared by hydrothermal method on the surface of AFC to investigate the ultrasonic piezoelectric catalysis effect. X-ray diffraction (XRD), Raman spectroscopy, energy dispersive x-ray spectroscopy (EDS) and scanning electron microscopy (SEM) were used to analyze the structure and morphology of CuO-BTO/AFC composite. It is found that the CuO-BTO/AFC composite exhibits excellent piezo-catalytic performance for the degradation of organics promoted by ultrasonic vibration. The CuO-BTO/AFC composite can decompose methyl orange and methylene blue with degradation efficiency as high as 93.9% and 97.6% within 25 min, respectively. The mechanism of piezoelectricity enhanced ultrasound supported catalysis effect of system CuO-BTO/AFC is discussed. The formed heterojunction structure between BTO and CuO promotes the separation of positive and negative charges caused by the piezoelectric effect.
Two-dimensional molybdenum ditelluride waveguide-integrated near-infrared photodetector
Authors: Wang Xinxue , Zeng Guang , Shen Lei , Chen Wei , Du Fanyu , Chen Yu-Chang , Ding Si-Tong , Shi Cai-Yu , Zhang David Wei , Chen Liao , Lu Hong-Liang
Published: February 2024

Low-cost, small-sized, and easy integrated high-performance photodetectors for photonics are still the bottleneck of photonic integrated circuits applications and have attracted increasing attention. The tunable narrow bandgap of two-dimensional (2D) layered molybdenum ditelluride (MoTe2) from ∼0.83 to ∼1.1 eV makes it one of the ideal candidates for near-infrared (NIR) photodetectors. Herein, we demonstrate an excellent waveguide-integrated NIR photodetector by transferring mechanically exfoliated 2D MoTe2 onto a silicon nitride (Si3N4) waveguide. The photoconductive photodetector exhibits excellent responsivity (R), detectivity (D*), and external quantum efficiency at 1550 nm and 50 mV, which are 41.9 A W−1, 16.2 × 1010 Jones, and 3360%, respectively. These optoelectronic performances are 10.2 times higher than those of the free-space device, revealing that the photoresponse of photodetectors can be enhanced due to the presence of waveguide. Moreover, the photodetector also exhibits competitive performances over a broad wavelength range from 800 to 1000 nm with a high R of 15.4 A W−1 and a large D* of 59.6 × 109 Jones. Overall, these results provide an alternative and prospective strategy for high-performance on-chip broadband NIR photodetectors.
Nanotoxicity of two-dimensional nanomaterials on human skin and the structural evolution of keratin protein
Authors: Yin Changji , Yu Lei , Feng Lei , Zhou Joey Tianyi , Du Chunbao , Shao Xiaoshan , Cheng Yuan
Published: February 2024

Two-dimensional (2D) materials have been increasingly widely used in biomedical and cosmetical products nowadays, yet their safe usage in human body and environment necessitates a comprehensive understanding of their nanotoxicity. In this work, the effect of pristine graphene and graphene oxide (GO) on the adsorption and conformational changes of skin keratin using molecular dynamics simulations. It is found that skin keratin can be absorbed through various noncovalent driving forces, such as van der Waals (vdW) and electrostatics. In the case of GO, the oxygen-containing groups prevent tighter contact between skin keratin and the graphene basal plane through steric effects and electrostatic repulsion. On the other hand, electrostatic attraction and hydrogen bonding enhance their binding affinity to positively charged residues such as lysine and arginine. The secondary structure of skin keratin is better preserved in GO system, suggesting that GO has good biocompatibility. The charged groups on GO surface perform as the hydrogen bond acceptors, which is like to the natural receptors of keratin in this physiological environment. This work contributes to a better knowledge of the nanotoxicity of cutting-edge 2D materials on human health, thereby advancing their potential biological applications.
Synthesis of carbon quantum dots/porous aromatic frameworks (CQDs/PAF-45) composites and their enhanced photocatalytic performance
Authors: Liu Xianhao , Timur Meng , Peng Yuyue , Yu Jinsheng , Li Lina
Published: February 2024

Modification and functionalization of porous aromatic framework (PAF) materials have emerged as crucial research directions in various fields. In this study, we employed a hydrothermal method to synthesize a carbon quantum dots (CQDs) solution. By loading different amounts of CQDs onto the surface of PAF-45 material through ultrasonic and hydrothermal treatments, we successfully formed CQDs/PAF-45 composite materials. The introduction of CQDs effectively transformed the hydrophobic nature of PAF-45 into a hydrophilic material, thereby overcoming the challenge of achieving efficient contact between PAF catalysts and reactants in aqueous solutions. In the photocatalytic degradation experiments of Rhodamine B (RhB), tetracycline, CQDs/PAF-45 composite materials surpassed that of the pristine PAF-45 material. Notably, the 1 wt% CQDs/PAF-45 composite material exhibited the highest photocatalytic activity, with degradation efficiencies for Rhodamine B, tetracycline, and phenol approximately 1.4 times, 1.5 times and 1.5 times higher than those of the PAF-45 material, respectively.
CdSe nanostructured thin film by electrophoretic deposition for quantum dots sensitized solar cell
Authors: Kyaw Hay Mar Aung , Ishak Mohamad Nizam , Mohd Noor Ahmad Fauzi , Kawamura Go , Matsuda Atsunori , Yaacob Khatijah Aisha
Published: February 2024

Cadmium selenide (CdSe) quantum dots (QDs) with different size, 2.5 and 3.2 nm, were successfully deposited on mesoporous titanium dioxide (TiO2) (Degussa-P25) nanostructures by electrophoretic deposition method (EPD) at the applied voltage 100 V for 120 s deposition time. In this study, the morphology of CdSe films deposited by EPD and the performance of the film when assembled into a solar cell were investigated. From the field emission scanning electron microscopy cross-section, the thickness of the CdSe nanoparticles with size 2.5 nm films were 3.4 and 3.0 μm for CdSe 3.2 nm nanoparticles film. The structure of 2.5 nm is denser than compare of 3.2 nm CdSe nanoparticles. From UV visible spectroscopy, the band gap calculated for 2.5 nm CdSe nanoparticles is 2.28 eV and for 3.2 nm is 2.12 eV. Photovoltaic characterization was performed under an illumination of 100 mW cm−2. A photovoltaic conversion efficiency of 1.81% was obtained for 2.5 nm CdSe and 2.1% was obtained for 3.2 nm CdSe nanoparticles. This result shows that the photovoltaic efficiency is dependent on CdSe nanoparticle size.
A triple-imaging-modality system for simultaneous measurements of prompt gamma photons, prompt x-rays, and induced positrons during proton beam irradiation
Authors: Yamamoto Seiichi , Watabe Hiroshi , Nakanishi Kohei , Yabe Takuya , Yamaguchi Mitsutaka , Kawachi Naoki , Kamada Kei , Yoshikawa Akira , Miyake Masayasu , Tanaka Kazuo S , Kataoka Jun
Published: February 2024

Objective. Prompt gamma photon, prompt x-ray, and induced positron imaging are possible methods for observing a proton beam’s shape from outside the subject. However, since these three types of images have not been measured simultaneously nor compared using the same subject, their advantages and disadvantages remain unknown for imaging beam shapes in therapy. To clarify these points, we developed a triple-imaging-modality system to simultaneously measure prompt gamma photons, prompt x-rays, and induced positrons during proton beam irradiation to a phantom. Approach. The developed triple-imaging-modality system consists of a gamma camera, an x-ray camera, and a dual-head positron emission tomography (PET) system. During 80 MeV proton beam irradiation to a polymethyl methacrylate (PMMA) phantom, imaging of prompt gamma photons was conducted by the developed gamma camera from one side of the phantom. Imaging of prompt x-rays was conducted by the developed x-ray camera from the other side. Induced positrons were measured by the developed dual-head PET system set on the upper and lower sides of the phantom. Main results. With the proposed triple-imaging-modality system, we could simultaneously image the prompt gamma photons and prompt x-rays during proton beam irradiation. Induced positron distributions could be measured after the irradiation by the PET system and the gamma camera. Among these imaging modalities, image quality was the best for the induced positrons measured by PET. The estimated ranges were actually similar to those imaged with prompt gamma photons, prompt x-rays and induced positrons measured by PET. Significance. The developed triple-imaging-modality system made possible to simultaneously measure the three different beam images. The system will contribute to increasing the data available for imaging in therapy and will contribute to better estimating the shapes or ranges of proton beam.
Quantifying the accuracy of inter-beat intervals acquired from consumer-grade photoplethysmography wristbands using an electrocardiogram-aided information-based similarity approach
Authors: Cui Xingran , Wang Jing , Xue Shan , Qin Zeguang , Peng Chung-Kang
Published: February 2024

Objective. Although inter-beat intervals (IBI) and the derived heart rate variability (HRV) can be acquired through consumer-grade photoplethysmography (PPG) wristbands and have been applied in a variety of physiological and psychophysiological conditions, their accuracy is still unsatisfactory. Approach. In this study, 30 healthy participants concurrently wore two wristbands (E4 and Honor 5) and a gold-standard electrocardiogram (ECG) device under four conditions: resting, deep breathing with a frequency of 0.17 Hz and 0.1 Hz, and mental stress tasks. To quantitatively validate the accuracy of IBI acquired from PPG wristbands, this study proposed to apply an information-based similarity (IBS) approach to quantify the pattern similarity of the underlying dynamical temporal structures embedded in IBI time series simultaneously recorded using PPG wristbands and the ECG system. The occurrence frequency of basic patterns and their rankings were analyzed to calculate the IBS distance from gold-standard IBI, and to further calculate the signal-to-noise ratio (SNR) of the wristband IBI time series. Main results. The accuracies of both HRV and mental state classification were not satisfactory due to the low SNR in the wristband IBI. However, by rejecting data segments of SNR < 25, the Pearson correlation coefficients between the wristbands' HRV and the gold-standard HRV were increased from 0.542 ± 0.235 to 0.922 ± 0.120 for E4 and from 0.596 ± 0.227 to 0.859 ± 0.145 for Honor 5. The average accuracy of four-class mental state classification increased from 77.3% to 81.9% for E4 and from 79.3% to 83.3% for Honor 5. Significance. Consumer-grade PPG wristbands are acceptable for HR and HRV monitoring when removing low SNR segments. The proposed method can be applied for quantifying the accuracies of IBI and HRV indices acquired via any non-ECG system.
A differentiable actuator extends potential configurations of modular robots
Authors: Li Henghao , Zhang Xiaolin , Liang Weijian , Xiao Endong , Huang Wenkai
Published: February 2024

Mesenchymal stem cells (MSCs) can be differentiated into various cell lineages under the influence of mechano-niche. Inspired by this approach, this study presents a differentiable stem cell actuator unit (SAU) driven by a shape memory alloy, and a modular robotic framework. Similar to mechanically guided differentiation of MSCs, SAUs can be differentiated into a series of differentiated actuator units (DAUs) under external preload. This process has been modeled, simulated, and experimentally validated, with testing conducted on three distinct types and 14 specifications of DAUs. DAUs weighing as light as 1.96g exhibited outputs reaching up to 10.6 N and 46.32 Nmm. Our team has developed seven application prototypes based on this bio-inspired framework including mobile robots, manipulators and end effectors. This work pioneers the integration of differentiable concepts and principles into the design of modular robots, enabling a wider range of potential configurations and capabilities.
High-efficient and intelligent antibacterial face mask integrated with airflow-temperature dual-function sensors for respiratory monitoring and disease prevention
Authors: Lan Xingzi , Chen Xinyu , Chen Xin , Fan Hao , Zheng Hehui , Wang Han , Tang Yadong
Published: February 2024

Intelligent face masks play crucial roles in health monitoring and disease prevention, having attracted huge attention in recent years. However, most of the current intelligent face masks focus on monitoring single physical signal, which were unable to provide comprehensive information. Herein, an intelligent face mask with airflow and temperature sensing abilities, high-efficiency filtration and excellent antibacterial activity was proposed. The real-time airflow monitoring was realized by a triboelectric nanogenerator (TENG), which was composed of electrospun nanofibrous membrane and polydimethylsiloxane (PDMS) composite film. The fabricated electrospun nanofibrous membrane simultaneously played roles as tribo-positive material, filter and antibacterial membrane. The PDMS composite film prepared by co-blending and surface modification was applied as tribo-negative material. It was found that the combination of co-blending and surface modification enhanced the tribo-negative property of the PDMS film, resulting in an increment of output performance of TENG. The TENG integrated into a face mask could monitor respiratory rate and respiration intensity in real time. Additionally, the temperature sensing was achieved by a serpentine PDMS/laser-induced graphene temperature sensor. The temperature sensor exhibited a temperature coefficient of resistance of 0.316% °C−1, which could detect subtle temperature variations. Furthermore, the electrospun nanofibrous membrane exhibited excellent filtration performance and antibacterial activity. Therefore, the prepared intelligent face mask showed promising potential for healthcare applications.
A phase-transition model of reprocessible thermadapt shape memory polymer
Authors: Mu Tong , Jia Fei , Zhao Wei , Liu Yanju , Leng Jinsong
Published: February 2024

A new type of thermadapt shape memory polymer (SMP) has not only the processability of thermoplastic SMP, but also the excellent shape fixation of thermosetting SMP. To enhance the application of this thermadapt SMP within industrial sectors, a comprehensive constitutive model based on phase transition is being proposed as an indicative descriptor of the semi-crystalline thermadapt SMP’s salient features, predominantly related to its two-way shape memory effect (SME) and thermal reprocessability. The concept of cooling elongation is also introduced in this model for modeling the two-way SME during the crystallization process. The molecular mechanism of chain-packing has been studied and used to establish phenomenological formulas. In addition, to systematically assess the temperature-time dependence of the crystallization process, the Avrami equation is improved by incorporating the distribution of polymer chain segments. This strategy provides a detailed investigation into the evolving pattern of the crystallization process in response to various temperature and time conditions. Compared with the experimental results, it is found that our model can well capture mechanical behavior in multiple shape memory cycles, including the two-way SME and reshaping process caused by bond exchange reaction. Furthermore, the potential application of SMP in smart mandrels is explored because the cooling elongation feature is able to endow it with self-adaptive expansion ability.
Light-induced nonlinear spin Hall current in single-layer WTe2
Authors: Bhalla Pankaj , Rostami Habib
Published: February 2024

In this theoretical investigation, we analyze light-induced nonlinear spin Hall currents in a gated single-layer 1T

′

-WTe2, flowing transversely to the incident laser polarization direction. Our study encompasses the exploration of the second and third-order rectified spin Hall currents using an effective low-energy Hamiltonian and employing the Kubo’s formalism. We extend our analysis to a wide frequency range spanning both transparent and absorbing regimes, investigating the influence of light frequency below and above the optical band gap. Additionally, we investigate the influence of an out-of-plane gate potential on the system, disrupting inversion symmetry and effectively manipulating both the strength and sign of nonlinear spin Hall responses. We predict a pronounced third-order spin Hall current relative to its second-order counterpart. The predicted nonlinear spin currents show strong anisotropic dependence on the laser polarization angle. The outcomes of our study contribute to a generalized framework for nonlinear response theory within the spin channel will impact the development of emerging field of opto-spintronic.
Classical-quantum correspondence for particles in the Penning trap
Authors: Bialynicki-Birula Iwo , Bialynicka-Birula Zofia
Published: February 2024

We derive new solutions of the Schrödinger equation which describe the motion of particles in the Penning trap. These solutions are direct counterparts of classical orbits. They are obtained by injection of classical trajectories into the wave functions of stationary solutions.
Strong convergence theorem for split null point, split variational inequality and fixed point problems for a non-expansive semigroup
Authors: Husain Shamshad , Khairoowala Mubashshir U , Furkan Mohd
Published: February 2024

The primary goal of this paper is to find a common solution of a split null point problem, split variational inequality problem and fixed point problem for a non-expansive semigroup with the help of new type of iterative algorithm. We construct that the sequences induced by the proposed iterative method to solve the above stated problems in the setting of real Hilbert spaces and obtain a strong convergence theorem. We also deduce certain consequences from the main convergence result. At the end, we provide a numerical experiment to demonstrate the convergence analysis of proposed iterative method. The methodology and conclusion described in this work extend and unify previously published findings in this field.
Study of viable compact stellar structures in non-Riemannian geometry
Authors: Gul M Zeeshan , Sharif M , Arooj Adeeba
Published: February 2024

The main objective of this article is to study the viable compact stellar structures in non-Riemannian geometry, i.e.,

f
(
Q
,
T
)

theory, where

Q

defines the non-metricity and T represents trace of the stress-energy tensor. In this perspective, we consider a static spherical metric with anisotropic matter configuration to examine the geometry of considered compact stars. A specific model of this theory is used to derive the explicit expressions of energy density and pressure components that govern the relationship between matter and geometry. The unknown parameters are evaluated by using the continuity of inner and outer spacetimes to examine the configuration of spherical stellar structures. Physical parameters such as fluid characteristics, energy constraints and equation of state parameters are analyzed to examine the viability of the considered stellar objects. Further, we use Tolman-Oppenheimer-Volkoff equation, sound speed and adiabatic index methods to analyze the equilibrium state and stability of the proposed stellar objects. The rigorous analysis and satisfaction of necessary conditions lead to the conclusion that the stellar objects studied in this framework are viable and stable.
Raychaudhuri equation and the dynamics of cosmic evolution
Authors: Chakraborty Madhukrishna , Chakraborty Subenoy
Published: February 2024

The paper deals with the Raychaudhuri equation (RE) which is a non-linear ordinary differential equation in Θ, the expansion scalar corresponding to a geodesic flow. Focusing theorem which follows as a consequence of the RE has been restated in terms of the cosmic parameter q (deceleration parameter) both for Einstein gravity and for modified gravity theories. Measurable quantities namely the luminosity distance and density parameter are shown to have an upper bound using the Raychaudhuri scalar. An analogy between geometric and cosmological RE has been made. Subsequently, to find the solution of the non-linear RE a transformation of variable related to the metric scalar of the hyper-surface has been identified which converts the former to a second order differential equation. Finally, the first integral of this second order differential equation gives the entire picture of the dynamics of cosmic evolution
Primordial black holes dark matter and secondary gravitational waves from warm Higgs-G inflation
Authors: Arya Richa , Jain Rajeev Kumar , Mishra Arvind Kumar
Published: February 2024

We explore the role of dissipative effects during warm inflation leading to the small-scale enhancement of the power spectrum of curvature perturbations. In this paper, we specifically focus on non-canonical warm inflationary scenarios and study a model of warm Higgs-G inflation, in which the Standard Model Higgs boson drives inflation, with a Galileon-like non-linear kinetic term.
We show that in the Galileon-dominated regime, the primordial power spectrum is strongly enhanced, leading to the formation of primordial black holes (PBH) with a wide range of the mass spectrum.
Interestingly, PBHs in the asteroid mass window ∼ (1017–1023) g are generated in this model, which can explain the total abundance of dark matter in the Universe.
In our analysis, we also calculate the secondary gravitational waves (GW) sourced by these small-scale overdense fluctuations and find that the induced GW spectrum can be detected in future GW detectors, such as LISA, BBO, DECIGO, etc. Our scenario thus provides a novel way of generating PBHs as dark matter and a detectable stochastic GW background from warm inflation. We also show that our scenario is consistent with the swampland and the trans-Planckian censorship conjectures and, thus, remains in the viable landscape of UV complete theories.
Shedding light on neutrino self-interactions with solar antineutrino searches
Authors: Wu Quan-feng , Xu Xun-Jie
Published: February 2024

Solar antineutrinos are absent in the standard solar model prediction. Consequently, solar
antineutrino searches emerge as a powerful tool to probe new physics capable of converting
neutrinos into antineutrinos. In this study, we highlight that neutrino self-interactions,
recently gaining considerable attention due to their cosmological and astrophysical implications,
can lead to significant solar antineutrino production. We systematically explore various types of
four-fermion effective operators and light scalar mediators for neutrino self-interactions. By
estimating the energy spectra and event rates of solar antineutrinos at prospective neutrino
detectors such as JUNO, Hyper-Kamiokande, and THEIA, we reveal that solar antineutrino searches
can impose stringent constraints on neutrino self-interactions and probe the parameter space
favored by the Hubble tension.
The International Astronomical Search Collaboration (IASC)—Citizen Scientist System for Asteroid Discovery
Authors: Miller Patrick , Weryk Robert , Wainscoat Richard , Perret Jules , Hartung Steve , Vorobjov Tomas , Buzzi Luca , Raab Herbert , Chastel Serge , Fairlamb John , Huber Mark , Ramanjooloo Yudish , Chambers Kenneth , de Boer Thomas , Gao Hua , Lin Roger Chien-Cheng , Magnier Eugene , Pennypacker Carlton
Published: February 2024

We describe a citizen science asteroid detection system developed by the International Astronomical Search Collaboration (IASC) and the Institute for Astronomy at the University of Hawaii, utilizing data from the Pan-STARRS telescopes. The goals of this project are to (i) educate and engage citizen scientists (mostly high school students) in science and astronomy, (ii) search for new asteroids to extend the limiting magnitudes of existing asteroid surveys, and (iii) find missed Near-Earth Objects (NEOs—objects with perihelia q < 1.3 au) to support planetary defense efforts. Over the past 15 yr, 50,000 citizen scientists from 96 countries around the world have detected ∼12,000 main-belt asteroids and ∼5 NEOs. Citizen scientists use the software Astrometrica during scheduled campaigns to search for and measure asteroid astrometry and photometry, and submit the data to IASC for vetting. Candidate detections not already submitted by Pan-STARRS are then submitted to the Minor Planet Center, and are typically ∼0.30 ± 0.07 mag fainter.
Hybrid modeling and optimization of fiber laser hole cutting of austenitic stainless-steel sheets using response surface
Authors: Niu Zhenhua , Dehkordi Mohammad Hossein Razavi , Ghazi Mohammadreza , Akbari Mohammad
Published: February 2024

In this study, an efficient approach was proposed to systematically model and optimize the laser small hole cutting process parameters using a hybrid approach for the design of experiment and multi-objective genetic algorithm optimization. The central composite design and response surface methodology were used to effectively model the impact of four main factors: cutting speed, laser power, gas pressure and focal distance on the responses. The responses considered were hole diameter circularity tolerance, spattering and cut kerf width, which were used to evaluate the quality of the laser hole cutting. The regression equations were used to model the effect of process parameters and their interactions on the responses. These regression models were then used as objective functions for optimization. The results show that the focal distance and laser power have had a significant influence on the hole diameter circularity tolerance and the variation in size of the cut kerf. In particular, the melted material spattering rate increased threefold when the focal distance increased from 0.4 to 0.8 mm. The optimization results highlighted that the best outcomes in terms of minimum deviation, spatter, and the cut-kerf width were achieved at low power (between 605 and 685 W) and low speeds (in the range of 11.1–12.7 m min−1). The optimal focal distance for all solutions was found to be 0 mm for the gas pressure (between 6.5 and 8 bars) to minimize the objective functions.
Theory and verification of moiré fringes for x-ray three-phase grating interferometer
Authors: Shan 单 Yu-Zheng 雨征 , Ge 葛 Yong-Shuai 永帅 , Yang 杨 Jun 君 , Guo 郭 Da-Yu 大育 , Cai 蔡 Xue-Bao 学宝 , Liu 刘 Xiao-Ke 晓珂 , Hou 侯 Xiao-Wen 晓文 , Guo 郭 Jin-Chuan 金川
Published: February 2024

Dual-phase and three-phase grating x-ray interference is a promising new technique for grating-based x-ray differential phase contrast imaging. Dual-phase grating interferometers have been relatively completely studied and discussed. In this paper, the corresponding imaging fringe formula of the three-phase grating interferometer is provided. At the same time, the similarities and differences between the three-phase grating interferometer and the dual-phase grating interferometer are investigated and verified, and that the three-phase grating interferometer can produce large-period moiré fringes without using the analyzing grating is demonstrated experimentally. Finally, a simple method of designing three-phase grating and multi-grating imaging systems from geometric optics based on the thin-lens theory of gratings is presented. These theoretical formulas and experimental results provide optimization tools for designing three-phase grating interferometer systems.