bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of microneedle based blood extraction device
Authors: Dong Chao-Wei , Lee Kang-Hyuk , Na Jong-Hyun , Joo Dong-Hyun , Choi Jin-Ho , Park Woo-Tae
Published: January 2024

Microneedles can extract various analytics from the human body in a minimally invasive manner and provide real-time diagnosis, making microneedle-based point-of-care testing devices increasingly popular. In this paper, we propose a press-activated blood extraction system that integrates solid microneedles and 3D-printed blood collection devices for efficient blood extraction. The technology combines a solid microneedle array, a high-speed insertion mechanism, a negative pressure generating structure, and a blood reservoir containing lithium heparin anticoagulant into a compact, self-contained device. The device requires minimal training, as blood can be drawn with a simple finger push of the silicone chamber. This device is more convenient and less painful than finger sticks and venipuncture.
Fabrication of transparent p-CuI/n-ZnO heterojunction with excellent ideality factor
Authors: Yang Zhe , Li Mingchen , Wang Wanxia , Gong Jianhong , Sun Honggang , Sun Hui
Published: January 2024

Copper iodide (CuI) is an intrinsically transparent p-type semiconductor with a wide band gap of about 3.1 eV. In this work, Cu3N films were prepared as precursors through high-power impulse magnetron sputtering and then were solid-phase iodinated at room temperature for the preparation of transparent CuI films. Subsequently, transparent p-CuI/n-ZnO heterojunctions were fabricated wherein ZnO layers were deposited by radio frequency magnetron sputtering. After the properties are optimized by annealing, the heterojunctions exhibit significant rectification characteristics. The influence of annealing temperature on the electrical properties of the heterojunctions have been investigated. The optimal ideality factor of about 1.22 can be obtained with a rectification ratio of 1.05 × 105 after the heterojunctions annealing at 100 °C. This value is superior to most of the results reported in the literature. Meanwhile, the light-to-dark current ratio and the transmittance in the visible region of the heterojunction have also been studied. The light-to-dark current ratio is significant at 6.42 × 106. The average transmittance of the heterojunctions is 72.7%. These findings demonstrate the potential applications of CuI for optoelectronic devices and the promising prospects of p-CuI/n-ZnO heterojunction-based photodetectors and other optoelectronic devices.
Broadband ultraviolet photodetector based on rare-earth metal oxide Nd2O3
Authors: Fang Lulei , Liu Xinyan , Zhang Yongfeng , Ruan Shengping , Liu Caixia , Ma Yan , Li Xin , Chen Yu , Zhou Jingran
Published: January 2024

The detection of ultraviolet (UV) radiation holds significant importance in various fields. As the demand for superior detector performance grows alongside advancements in science and technology, there is a need for detectors with larger light-to-dark rejection ratios and lower standby power consumption. This paper presents the outstanding performance of the rare earth metal oxide Nd2O3 in broadband UV detection. With a wide forbidden band width of 4.6 eV, eliminating the requirement for additional filters, Nd2O3 emerges as an ideal material for broadband UV detectors. The device exhibits remarkable characteristics, including a dark current of only 1.66 × 10−11 A at a 5 V bias voltage, a light-to-dark rejection ratio of 1.33 × 103 at 280 nm and 15 μW cm−2, a responsiveness of 0.061 A W−1, and a detection rate of 4.7 × 1012 Jones. Furthermore, the performance of the device can be significantly enhanced through the formation of a heterojunction with TiO2. The heterojunction device exhibits a shortened response time of 78.64%, a reduced recovery time of 88.97%, and an increased light-to-dark rejection ratio of 2.75 × 103 at a 5 V bias voltage. This significant improvement in performance highlights the potential of the Nd2O3/TiO2 heterojunction in broadband UV detection.
Investigation of the dependence of temperature attenuation of the layered bio-tissue
Authors: Zhao Peng , Shi Wanting , Tong Shiqi , Wang Yuebing , Chen Jinling , Hu Xiaoye , Shen Hong , Zhao Jing
Published: January 2024

High-intensity focused ultrasound for solid tumor ablation is a noninvasive ultrasound hyperthermia technique wherein ultrasound is transmitted through multiple layers of biological tissues, focusing on the target area. The resulting heat accumulates in the target tissue, leading to irreversible cell death or protein necrosis, achieving tumor ablation. During treatment, the efficiency of acoustic energy converting to heat is closely related to temperature attenuation in the layered tissues. To obtain an accurate prediction of thermal damage, variations in the acoustic parameters should be measured at different temperatures. This study used two methods to induce heating to the tissues: the water heating method (WHM), which involves heat transfer from the outside to the inside, and the ultrasound heating method (UHM), wherein the heat source is located inside the tissue. The finite-amplitude insertion-substitution method was utilized to determine the attenuation coefficients of various bio-tissues such as porcine fat, muscle, and liver as the temperature increased. To mitigate the effects of viscous heating artifacts, the ‘wait then measure’ (WTM) thermometric approach was utilized using wire thermocouples to measure the temperature of the ultrasound-heated tissue. Experimental results demonstrate that the attenuation coefficient of bio-tissues varies with temperature under different heating methods. This study presents the variation in tissue attenuation using WHM at 5 MHz, while tissue categories using UHM are modeled with formulas at a frequency of 2 MHz.
Alternative 3-3-1 models with exotic electric charges
Authors: Suarez Eduard , Benavides Richard H , Giraldo Yithsbey , Ponce William A , Rojas Eduardo
Published: January 2024

We report the most general classification of 3-3-1 models with

β
=

3

. We found several solutions where anomaly cancellation occurs among fermions of different families. These solutions are particularly interesting as they generate non-universal heavy neutral vector bosons. Non-universality in the standard model fermion charges under an additional gauge group generates charged lepton flavor violation and flavor changing neutral currents; we discuss under what conditions the new models can evade constraints coming from these processes. In addition, we also report the Large Hadron Collider~(LHC) constraints.
Noncentrosymmetric two-dimensional Weyl semimetals in porous Si/Ge structures
Authors: Lopes Emmanuel V C , Baierle Rogério J , Miwa Roberto H , Schmidt Tome M
Published: January 2024

In this work we predict a family of noncentrosymmetric two-dimensional (2D) Weyl semimetals (WSMs) composed by porous Ge and SiGe structures. These systems are energetically stable graphenylene-like structures with a buckling, spontaneously breaking the inversion symmetry. The nontrivial topological phase for these 2D systems occurs just below the Fermi level, resulting in nonvanishing Berry curvature around the Weyl nodes. The emerged WSMs are protected by C
3 symmetry, presenting one-dimensional edge Fermi-arcs connecting Weyl points with opposite chiralities. Our findings complete the family of Weyl in condensed-matter physics, by predicting the first noncentrosymmetric class of 2D WSMs.
GNSS blanket jamming classification algorithm based on spatial attention mechanism and residual shrinkage neural network
Authors: Lin Zijian , Zhuang Xuebin , Niu Ben , Zeng Kun
Published: January 2024

In the context of an increasingly complex electromagnetic environment, satellite navigation systems have become highly susceptible to jamming. Detecting and classifying jamming has thus become crucial for taking effective anti-jamming measures. This paper addresses the issue that the classification accuracy of blanket jamming declines drastically in low jamming-to-noise ratio (JNR) scenarios. To tackle this challenge, a novel algorithm is proposed that combines the spatial attention mechanism with a residual shrinkage neural network (RSN-SA) to classify ten types of blanket jamming, ranging from single jamming to convolutional compound jamming. Specifically, the proposed algorithm first employs the Fourier Synchrosqueezed Transform to extract time-frequency (TF) domain features from the original jamming signal, generating corresponding TF images. Then, the RSN-SA is employed to identify and classify these images effectively while minimizing the impact of noise-related features. This allows the main parts of the TF images to be focused on, resulting in higher recognition accuracy. Simulation results demonstrate that RSN-SA achieves close to 100% accuracy for six single blanket jamming signals. Moreover, compared with the other five algorithms, RSN-SA effectively enhances the classification accuracy of convolutional compound jamming signals in low JNR scenarios and improves the recognition stability in high JNR scenarios. Overall, the proposed algorithm provides a promising solution for classifying blanket jamming in satellite navigation systems with high accuracy and robustness.
Application of deep learning to fault diagnosis of rotating machineries
Authors: Su Hao , Xiang Ling , Hu Aijun
Published: January 2024

Deep learning (DL) has attained remarkable achievements in diagnosing faults for rotary machineries. Capitalizing on the formidable learning capacity of DL, it has the potential to automate human labor and augment the efficiency of fault diagnosis in rotary machinery. These advantages have engendered escalating interest over the past decade. Although recent reviews of the literature have encapsulated the utilization of DL in diagnosing faults in rotating machinery, they no longer encompass the introduction of novel methodologies and emerging directions as DL methodologies continually evolve. Moreover, in practical application, novel issues and trajectories perpetually manifest, demanding a comprehensive exegesis. To rectify this lacuna, this article amalgamates current research trends and avant-garde methodologies while systematizing the utilization of anterior DL techniques. The evolution and extant status of DL in diagnosing faults for rotary machinery were delineated, with the intent of providing orientation for prospective research. Over the bygone decade, archetypal DL theory has empowered the diagnosis of faults in rotating machinery by directly establishing the nexus between mechanical data and fault conditions. In recent years, meta learning methods aimed at solving small sample scenarios and large model transformers aimed at mining big data features have both received widespread attention and development in the field of fault diagnosis of rotating machinery equipment. Although excellent results have been achieved in these two directions, there is no review and summary article yet, so it is necessary to update the review literature in the field of fault diagnosis of rotating machinery equipment. Lastly, predicated on a survey of the literature and the current developmental landscape, the challenges and prospective orientations of DL in rotary machinery fault diagnosis are presented.
Enhanced robot obstacle avoidance strategy: efficient distance estimation and collision avoidance for hidden robots
Authors: Zhang Xiaojun , Li Minglong , Jia Jidong , Sun Lingyu , Li Manhong , Zhang Minglu
Published: January 2024

Human-robot interaction is crucial for the future of smart factories and new industrial systems. Safety in robotics has always been a top priority, with external sensors being studied to construct safety perception systems for robots. This paper proposes an obstacle avoidance strategy based on an efficient distance estimation method using a vision sensor to address the challenge of robot occlusion. The method fuses depth images with a predefined robot skeleton model to estimate robot pose in real time, and uses the optimized potential field model to achieve full-body collision avoidance. Comparative experiments validate the efficiency of the proposed method, which represents a significant contribution to enhancing human–robot interaction and safety in industrial settings.
Preparation and properties of oxidized multi-walled carbon nanotube superhydrophobic composites modified by bio-fatty acids
Authors: Hao Xiaoru , Cheng Zhihao , Xie Jun , Zhang Yu , Zheng Haikun , Zhou Jiahui , Sheng Wei
Published: January 2024

In this paper, a preparation method of superhydrophobic composites of oxidized multi-walled carbon nanotubes modified by stearic acid (SA) is proposed. Hydroxylated multi-walled carbon nanotubes (HMWCNTs) were obtained by oxidizing multi-walled carbon nanotubes with potassium dichromate to give them hydroxyl groups on the surface. Subsequently, the carboxyl group in the SA molecule was esterified with the hydroxyl group on the HMWCNTs. SA molecules were grafted onto the surface of multi-walled carbon nanotubes. SA modified oxidized multi-walled carbon nanotubes (SMWCNT) superhydrophobic composites were obtained. The results show that the water contact angle (WCA) of superhydrophobic composites can reach up to 174°. At the same time, the modified nanocomposites have good anti-icing and corrosion resistance. After low temperature delayed freezing test, the freezing extension time of the nanocomposite film is 30 times that of the smooth surface. Under strong acid and alkali conditions, the superhydrophobic nanocomposites still maintain good superhydrophobicity. The nanocomposites may have potential applications in the preparation of large-scale superhydrophobic coatings.
Surfactant effect on energy storage performance of hydrothermally synthesized Ni3V2O8
Authors: Mandal Biswajit , Singh Jay , Raha Himadri , Mishra Vipul Vaibhav , Guha Prasanta Kumar
Published: January 2024

We report a study to improve the ternary oxide Ni3V2O8′s electrochemical energy storage capabilities through correct surfactanization during hydrothermal synthesis. In this study, Ni3V2O8 nanomaterials were synthesized in three different forms: one with a cationic surfactant (CTAB), one with an anionic surfactant (SLS), and one without any surfactant. FESEM study reveals that all the synthesized Ni3V2O8 nanomaterials had a small stone-like morphology. The electrochemical study showed that anionic surfactant-assisted Ni3V2O8 (NVSLS) had a maximum of 972 F g−1 specific capacitance at 1 A g−1 current density, whereas cationic surfactant-assisted Ni3V2O8 (NVCTAB) had the lowest specific capacitance of 162 F g−1. The specific capacitance and the capacitance retention of the NVSLS (85% after 4000 cycles) based electrode was much better than that of the NVCTAB (76% after 4000 cycles) based electrode. The improved energy storage properties of the NVSLS electrode are attributed to its high diffusion coefficient, high surface area, and enriched elemental nickel, as compared to the NVCTAB electrode. All these excellent electrochemical properties of NVSLS electrode indicates their potential usage in asymmetric supercapacitor application.
Existence and uniqueness of solutions to the Peierls–Nabarro model in anisotropic media
Authors: Gao Yuan , Scott James M
Published: January 2024

We study the existence and uniqueness of solutions to the vector field Peierls–Nabarro (PN) model for curved dislocations in a transversely isotropic medium. Under suitable assumptions for the misfit potential on the slip plane, we reduce the 3D PN model to a nonlocal scalar Ginzburg–Landau equation. For a particular range of elastic coefficients, the nonlocal scalar equation with explicit nonlocal positive kernel is derived. We prove that any stable steady solution has a one-dimensional profile. As a result, we obtain that solutions to the scalar equation, as well as the original 3D system, are characterized as a one-parameter family of straight dislocations. This paper generalizes results found previously for the full isotropic case to an anisotropic setting.
Benign termination of runaway electron beams on ASDEX Upgrade and TCV
Authors: Sheikh U , Decker J , Hoppe M , Pedrini M , Sieglin B , Simons L , Cazabonne J , Caloud J , Cerovsky J , Coda S , Colandrea C , Dal Molin A , Duval B , Ficker O , Griener M , Papp G , Pautasso G , Paz-Soldan C , Reux C , Tomesova E , Wijkamp T , Upgrade Team the ASDEX ,   the TCV Team,   the MST1 Team
Published: January 2024

This paper discusses the development of a benign termination scenario for runaway electron (RE) beams on ASDEX Upgrade and TCV. A systematic study revealed that a low electron density (n
e) companion plasma was required to achieve a large MHD instability, which expelled the confined REs over a large wetted area and allowed for the conversion of magnetic energy to radiation. Control of the companion plasma ne was achieved via neutral pressure regulation and was agnostic to material injection method. The neutral pressure required for recombination was found to be dependent on impurity species, quantity and RE current. On TCV, n
e increased at neutral pressures above 1 Pa, indicating that higher collisionality between the REs and neutrals may lead to an upper pressure limit. The conversion of magnetic energy to radiated energy was measured on both machines and a decrease in efficiency was observed at high neutral pressure on TCV. The benign termination technique was able to prevent any significant increase in maximum heat flux on AUG from 200 to 600 kA of RE current, highlighting the ability of this approach to handle fully formed RE beams.
Opportunities for fundamental physics research with radioactive molecules
Authors: Arrowsmith-Kron Gordon , Athanasakis-Kaklamanakis Michail , Au Mia , Ballof Jochen , Berger Robert , Borschevsky Anastasia , Breier Alexander A , Buchinger Fritz , Budker Dmitry , Caldwell Luke , Charles Christopher , Dattani Nike , de Groote Ruben P , DeMille David , Dickel Timo , Dobaczewski Jacek , Düllmann Christoph E , Eliav Ephraim , Engel Jonathan , Fan Mingyu , Flambaum Victor , Flanagan Kieran T , Gaiser Alyssa N , Garcia Ruiz Ronald F , Gaul Konstantin , Giesen Thomas F , Ginges Jacinda S M , Gottberg Alexander , Gwinner Gerald , Heinke Reinhard , Hoekstra Steven , Holt Jason D , Hutzler Nicholas R , Jayich Andrew , Karthein Jonas , Leach Kyle G , Madison Kirk W , Malbrunot-Ettenauer Stephan , Miyagi Takayuki , Moore Iain D , Moroch Scott , Navratil Petr , Nazarewicz Witold , Neyens Gerda , Norrgard Eric B , Nusgart Nicholas , Pašteka Lukáš F , N Petrov Alexander , Plaß Wolfgang R , Ready Roy A , Pascal Reiter Moritz , Reponen Mikael , Rothe Sebastian , Safronova Marianna S , Scheidenerger Christoph , Shindler Andrea , Singh Jaideep T , Skripnikov Leonid V , Titov Anatoly V , Udrescu Silviu-Marian , Wilkins Shane G , Yang Xiaofei
Published: January 2024

Molecules containing short-lived, radioactive nuclei are uniquely positioned to enable a wide range of scientific discoveries in the areas of fundamental symmetries, astrophysics, nuclear structure, and chemistry. Recent advances in the ability to create, cool, and control complex molecules down to the quantum level, along with recent and upcoming advances in radioactive species production at several facilities around the world, create a compelling opportunity to coordinate and combine these efforts to bring precision measurement and control to molecules containing extreme nuclei. In this manuscript, we review the scientific case for studying radioactive molecules, discuss recent atomic, molecular, nuclear, astrophysical, and chemical advances which provide the foundation for their study, describe the facilities where these species are and will be produced, and provide an outlook for the future of this nascent field.
Characterization of magnetostrictive bi-stable rotational vibration energy harvester with integrated centrifugal effect
Authors: Dong Weiwei , Liang Quan , Liu Huifang , Mei Xutao , Shu Liang , Liu Zhanqi , Chang Yunlong
Published: January 2024

Rotational machinery is a common presence in dust still production, and the occurrence of operational failures in components like engines and turbine blades necessitates effective measures. To solve this challenge, remote structural health monitoring using energy harvesting and wireless sensors has been widely employed to realize self-powered sensing. This study proposes a magnet-induced bi-stable rotational energy harvester (REH), which utilizes the centrifugal effect to broaden the effective frequency bandwidth, enabling efficient energy harvesting in complex environments. A comprehensive mathematical model has been established to facilitate the dynamic characteristics of the bi-stable system, taking into account the centrifugal effect. The theoretical results demonstrate that the gap distance of magnetic configuration has great effects on the bi-stable system. Additionally, the centrifugal effect decided by the centrifugal radius and rotational speeds also affects the stable high-energy orbit oscillations. Furthermore, experimental results indicate that the proposed REH can effectively operate within the frequency range of 230–290 rpm, with a maximum RMS voltage of 780 mV and corresponding power of 4.35 mW. These findings validate the performance of the bi-stable magnetostrictive REH with the centrifugal effect and indicate its potential to effectively address the power supply challenges for wireless sensors. Overall, this study presents a promising solution for enhancing the energy harvesting performance of REH and also provides insights into the design of high-efficiency REH by magnet-induced nonlinearity and the centrifugal effect.
Few-shot meta transfer learning-based damage detection of composite structures
Authors: Chen Yan , Xu Xuebing , Liu Cheng
Published: January 2024

Damage detection and localization using data-driven approaches in carbon fiber reinforced plastics (CFRP) composite structures is becoming increasingly important. However, the performance of conventional data-driven methods degrades greatly under little amount of data. In addition, the scarcity of data corresponding to defect/damage conditions of CFRP structures lead to extreme data imbalance, which make this problem even more challenging. To address these challenges of few training data and the scarcity of damage samples, this paper proposes a few-shot meta transfer learning (FMTL)-based approach for damage detection in CFRP composite structures. This method leverages knowledge learnt from an unbalanced data domain generated from a single CFRP composite sample and adapts the knowledge to be applied for other data domains generated by CFRP samples with different structural properties. The contributions of this research include demonstrating the feasibility of harnessing knowledge from notably limited experiment data, designing an algorithm for configuring hyperparameters based on a specific FMTL task, and identifying the impacts of hyperparameters on learning performances. Results show that FMTL can improve the recall rate by at least 15% while preserving the ability to identify health conditions. This method can be extremely useful when we need to monitor health condition of critical CFRP structures, like airplanes, because they can rarely generate data under damage conditions for model training. FMTL enables us to build new models based on unbalanced source domain data with the cost of a minimal set of samples from the target domain.
M-Fractional soliton solutions of fifth order generalized nonlinear fractional differential equation via (G′/G

2
)-expansion method
Authors: Zafar Asim , Ashraf Muhammad , Saboor Abdul , Bekir Ahmet
Published: January 2024

The motivation of this research is to investigate four fifth order generalized nonlinear fractional differential equations. Here, we analyze a local derivative, as conformable sense called truncated M-fractional derivative. We also discuss some properties satisfied by the derivative. An effective analytical method namely

(
G
′

/

G

2

)

-expansion method combined with truncated M-fractional derivative will be studied. As a result, the different types of new soliton solutions were obtained such as dark soliton, bright soliton, kink soliton and periodic soliton wave solutions etc and are verified through MATHEMATICA. This approach is a strong contender for future use in resolving the other problems of a similar nature. A visualization of a few findings is given, which demonstrates the effectiveness and suitability of the suggested approach in producing solutions with well-understood physical behavior. The above mentioned method is more reliable and efficient and simple as compared to rest of the methods to solve the fifth order generalized nonlinear fractional differential equations. The results will also be displayed in two dimensional as well as in three dimensional plots.
22/43 GHz low-insertion-loss dual-polarized multi-layer bandpass frequency selective surfaces for millimeter astronomy
Authors: Tong Jinye , Zhong Weiye , Shi Jun , Li Jinji , Xu Zhixia
Published: January 2024

We design a frequency selective surface (FSS) capable of transmitting K-band and reflecting Q-band radio waves. The equivalent circuit approach assists the distribution of multi-layer FSS to achieve a third-order bandpass response with an incident angle of less than 30°. The unit structure consists of three metal layers embedded with two dielectric substrates. Especially, the FSS provides a 3 dB transmission bandwidth range from 18.6 to 26.7 GHz with a maximum measured insertion loss of 0.61 dB. Hence the proposed polarization-insensitive FSS with low insertion loss can be applied in the observation system of millimeter astronomy.
Parameter space geometry of the quartic oscillator and the double-well potential: classical and quantum description
Authors: Gonzalez Diego , Chávez-Carlos Jorge , Hirsch Jorge G , David Vergara J
Published: January 2024

We compute the quantum metric tensor and its scalar curvature for the anharmonic oscillator for positive and negative quadratic potentials, where the potential displays a double well, employing exact numerical and perturbative procedures. We also introduce a formulation of the classical analog of the quantum metric tensor by using a novel approach based on Fourier series, which is shown to reproduce the relevant quantum features involved in the parameter space. It is remarkable that both the exact quantum treatment and classical formalism recognize the negative oscillator parameter at which the ground state starts to be delocalized in two wells.
Matter-antimatter asymmetry and dark matter stability from baryon number conservation
Authors: Císcar-Monsalvatje Mar , Ibarra Alejandro , Vandecasteele Jérôme
Published: January 2024

There is currently no evidence for a baryon asymmetry in our universe. Instead, cosmological observations have only demonstrated the existence of a quark-antiquark asymmetry, which does not necessarily imply a baryon asymmetric Universe, since the baryon number of the dark sector particles is unknown.
In this paper we discuss a framework where the total baryon number of the Universe is equal to zero, and where the observed quark-antiquark asymmetry arises from neutron portal interactions with a dark sector fermion N that carries baryon number. In order to render a baryon symmetric universe throughout the whole cosmological history, we introduce a complex scalar χ, with opposite baryon number and with the same initial abundance as N.
Notably, due to the baryon number conservation, χ is absolutely stable and could have an abundance today equal to the observed dark matter abundance. Therefore, in this simple framework, the existence of a quark-antiquark asymmetry is intimately related to the existence (and the stability) of dark matter.
Neutrinos from Earth-bound dark matter annihilation
Authors: Pospelov Maxim , Ray Anupam
Published: January 2024

A sub-component of dark matter with a short collision length compared to a planetary size leads to efficient accumulation of dark matter in astrophysical bodies. We analyze possible neutrino signals from the annihilation of such dark matter and conclude that in the optically thick regime for dark matter capture, the Earth provides the largest neutrino flux. Using the results of the existing searches, we consider two scenarios for the neutrino flux, from stopped mesons and prompt higher-energy neutrinos. In both cases we exclude some previously unexplored parts of the parameter space (dark matter mass, its abundance, and the scattering cross section on nuclei) by recasting the existing neutrino searches.
WarmSPy: a numerical study of cosmological perturbations
in warm inflation
Authors: Montefalcone Gabriele , Aragam Vikas , Visinelli Luca , Freese Katherine
Published: January 2024

We present WarmSPy, a numerical code in Python designed to solve for the
perturbations' equations in warm inflation models and compute the corresponding scalar power
spectrum at CMB horizon crossing. In models of warm inflation, a radiation bath of temperature T
during inflation induces a dissipation (friction) rate of strength Q ∝ Tc
/ϕm
in the
equation of motion for the inflaton field ϕ. While for a temperature-independent dissipation
rate (c = 0) an analytic expression for the scalar power spectrum exists, in the case of a
non-zero value for c the set of equations can only be solved numerically. For c > 0 (c < 0), the
coupling between the perturbations in the inflaton field and radiation induces a growing
(decaying) mode in the scalar perturbations, generally parameterized by a multiplicative function
G(Q) which we refer to as the scalar dissipation function. Using WarmSPy, we provide an
analytic fit for G(Q) for the cases of c = {3,1,-1}, corresponding to three cases that have
been realized in physical models. Compared to previous literature results, our fits are more
robust and valid over a broader range of dissipation strengths
Q ∈ [10-7,104]. Additionally, for the first time, we numerically assess the stability of
the scalar dissipation function against various model parameters, inflationary histories as well
as the effects of metric perturbations. As a whole, the results do not depend appreciably on most
of the parameters in the analysis, except for the dissipation index c, providing evidence for
the universal behaviour of the scalar dissipation function G(Q).
Cosmological constraints from the tomography of DES-Y3 galaxies with CMB lensing from ACT DR4
Authors: Marques G.A. , Madhavacheril M.S. , Darwish O. , Shaikh S. , Aguena M. , Alves O. , Avila S. , Bacon D. , Baxter E.J. , Bechtol K. , Becker M.R. , Bertin E. , Blazek J. , Richard Bond J. , Brooks D. , Cai H. , Calabrese E. , Carnero Rosell A. , Carrasco Kind M. , Carretero J. , Cawthon R. , Crocce M. , da Costa L.N. , Pereira M.E.S. , De Vicente J. , Desai S. , Diehl H.T. , Doel P. , Doux C. , Drlica-Wagner A. , Dunkley J. , Elvin-Poole J. , Everett S. , Ferraro S. , Ferrero I. , Flaugher B. , Fosalba P. , García-Bellido J. , Gatti M. , Giannini G. , Gluscevic V. , Gruen D. , Gruendl R.A. , Gutierrez G. , Harrison I. , Colin Hill J. , Hinton S.R. , Hollowood D.L. , Honscheid K. , Huterer D. , Jeffrey N. , Kim J. , Kuehn K. , Lahav O. , Lemos P. , Lima M. , Huffenberger K.M. , MacCrann N. , Marshall J.L. , Mena-Fernández J. , Miquel R. , Mohr J.J. , Moodley K. , Muir J. , Naess S. , Nati F. , Page L.A. , Palmese A. , Plazas Malagón A.A. , Porredon A. , Prat J. , Qu F.J. , Raveri M. , Ross A.J. , Rykoff E.S. , Farren G.S. , Samuroff S. , Sanchez E. , Schubnell M. , Sehgal N. , Sevilla-Noarbe I. , Sheldon E. , Sherwin B.D. , Sifón C. , Smith M. , Spergel D.N. , Staggs S.T. , Suchyta E. , Tarle G. , To C. , Van Engelen A. , Weaverdyck N. , Weller J. , Wenzl L. , Wiseman P. , Wollack E.J. , Yanny B. ,   The ACT and DES collaborations
Published: January 2024

We present a measurement of the cross-correlation between the MagLim galaxies selected from the Dark Energy Survey (DES) first three years of observations (Y3) and cosmic microwave background (CMB) lensing from the Atacama Cosmology Telescope (ACT) Data Release 4 (DR4), reconstructed over ∼ 436 deg2 of the sky. Our galaxy sample, which covers ∼ 4143 deg2, is divided into six redshift bins spanning the redshift range of 0.20<z<1.05. We adopt a blinding procedure until passing all consistency and systematics tests. After imposing scale cuts for the cross-power spectrum measurement, we reject the null hypothesis of no correlation at 9.1σ. We constrain cosmological parameters from a joint analysis of galaxy and CMB lensing-galaxy power spectra considering a flat ΛCDM model, marginalized over 23 astrophysical and systematic nuisance parameters. We find the clustering amplitude S
8 ≡ σ
8(Ω
m
/0.3)0.5 = 0.75+0.04
-0.05. In addition, we constrain the linear growth of cosmic structure as a function of redshift. Our results are consistent with recent DES Y3 analyses and suggest a preference for a lower S
8 compared to results from measurements of CMB anisotropies by the Planck satellite, although at a mild level (< 2σ) of statistical significance.
Structure of persistently prominent stocks in financial dynamics
Authors: Qiu Tian , Sun Xiao-Wen , Chen Guang , Zhong Li-Xin
Published: January 2024

Prominent components of financial markets have been identified in previous studies using random matrix theory. However, these studies are typically conducted based on static periods. Although these components may dominate during certain periods, they may not necessarily maintain dominance. In financial dynamics, it is important to understand how dominant components persist. In this study, we reveal the structure of prominent stocks by determining the stocks that remain dominant, namely persistently prominent stocks, based on eigenvalue and eigenvector analyses of multiple short time windows. Structural persistence is investigated by a temporal correlation, which suggests better structural sustainability of the persistently prominent stocks for the sector mode and a more stable structure of the whole market for the market mode. Furthermore, persistently prominent stocks are found to have a higher cross-correlation than the whole market for the market mode but show a lower correlation in extreme market states and present a business sector effect for the sector mode.
Multiscaling in the 3D critical site-diluted Ising ferromagnet
Authors: Marinari E , Martin-Mayor V , Parisi G , Ricci-Tersenghi F , Ruiz-Lorenzo J J
Published: January 2024

We study numerically the appearance of multiscaling behavior in the 3D ferromagnetic Ising site-diluted model, in the form of a multifractal distribution of the decay exponents for the spatial correlation functions at the critical temperature. We have computed the exponents of the long-distance decay of higher moments of the correlation function, up to the 10th power, by studying three different quantities: global susceptibilities, local susceptibilities and correlation functions. We have found very clear evidence of multiscaling behavior.
Experimental research on energy recovery efficiency and dynamic characteristics of heavy electric forklift
Authors: Gong Wen
Published: January 2024

The heavy electric forklift adopts a high-voltage system with fast charging speed and a large amount of recoverable potential energy. Energy recovery can prolong the operation time and improve the overall efficiency of the machine significantly. The energy recovery system has a large flow range, and the system of a single hydraulic motor-permanent magnet synchronous motor cannot meet the actual working needs of the heavy electric forklift. This paper proposes a new energy recovery system with dual hydraulic motors and permanent magnet synchronous motors. The system has two work modes, single and dual modes. The system operates in the single mode for a low flow rate and the dual mode for a high flow rate. Experimental research on energy recovery efficiency and dynamic characteristics is carried out. The experimental results show that power generation efficiency is above 50% within a certain speed range.
Development of n-heptane/2-butyltetrahydrofuran mechanism based on decoupling approach
Authors: Chen Konghao , Lu Heng , Zhang Qingfeng
Published: January 2024

This study aims to investigate 2-butyltetrahydrofuran (2-BTHF) as a potential alternative to diesel engine fuel. In response to the fact that the chemical kinetic mechanism for the combustion of 2-BTHF blended with diesel has not yet been established, the present study simplified and optimized the mechanism of 2-BTHF and n-heptane by using the direct relationship diagram method and sensitivity analysis and constructed a combined 2-BTHF/n-heptane mechanism based on the decoupling method. The validation of experimental results shows that the combined mechanism can accurately predict the combustion process and agrees well with the experimental data, and thus a reliable 2-BTHF/n-heptane combined mechanism has been successfully established, which provides an effective tool for simulating the combustion of diesel and the mixture of 2-BTHF and diesel with a high degree of accuracy and applicability.
PV power prediction based on feature selection and GMM clustering
Authors: Peng Kun , Tan Xiaohong , Wang Zunming , Wu Yuelan , Cai Yuan
Published: January 2024

The increase in the installed capacity of photovoltaics (PV) brings great challenges to the stable operation of the power system. To improve the accuracy of PV power prediction, Spearman’s rank correlation coefficient and Grey Relation analysis (GRA) are combined to analyze and screen each meteorological feature to ensure the effectiveness and reasonableness of the input features. Based on the analysis of meteorological features, the Gaussian Mixture Models (GMM) clustering method is proposed to cluster the historical data sets. The historical data are clustered into two categories: simple PV power change and complex PV power change, which facilitates the model to learn the power change characteristics under different weather conditions. A Bidirectional Gated Recurrent Unit (BiGRU) prediction model is built to mine the timing properties of the two types of data and trained and tested separately. By setting several error evaluation indexes for comprehensive judgment, the methods in this paper are better than several other classical prediction methods and have a strong adaptability to different weather conditions.
Effect of H2S on high-pressure decarbonization of biogas based on aspen hysys
Authors: Ma Ke , Lu Yuangang , Li Zhenpeng , Dou Mingyaun
Published: January 2024

This paper studied the process of distributed methane purification and proposed a method to collect and separate carbon dioxide from methane by simulation. Aspen Hysys software was used to simulate the effect of hydrogen sulfide content change on methane compression, separation, and decarbonization purification process. The critical properties of methane, power consumption of the compressor, and caloric value of methane were qualitatively and quantitatively analyzed. Therefore, this article has significant guidance on how to improve the high value-added utilization of biogas, recover CO2 and utilize it with high quality, and reduce greenhouse gas emissions. It is also one of the key directions of biogas research both domestically and internationally.
Characterization of brazed plate heat exchanger performance based on experimental and coupled heat-fluid-solid numerical simulation
Authors: Wang Yujie , Ding Shuhuan , Yan Aibin , Wang Fu
Published: January 2024

A physical and mathematical model of a complete brazed plate heat exchanger (BPHE) with three layers and two channels was presented. Experiments were conducted on the BPHE using water as the fluid, and the experimental results were compared with the simulation results in terms of heat transfer efficiency and pressure drop. An analysis of the relationship between the Nusselt number and drag factor of the BPHE at a specific Reynolds was also provided, with a focus on identifying any errors. Furthermore, the internal flow and heat transfer characteristics of the BPHE were analyzed. The thermal stress and lifetime of the BPHE at different operating temperatures were simulated by using the heat-flow-solid coupling method. The results reveal that the presence of stress concentration points and the thermal stress increases while the lifetime decreases with the rise in operating temperature. In summary, the study demonstrates that the BPHE experiences stress concentration points and their intensity varies with the working temperature, thereby affecting the overall lifetime of the BPHE.
Three-dimensional numerical simulation and structural optimization of large steam ejectors in exhaust gas heat recovery systems
Authors: Hu Linjing , Juan Daxin , Wang Jiachen
Published: January 2024

By establishing a three-dimensional mathematical model based on the physical characteristics of the steam ejector and utilizing computational fluid dynamics (CFD) method, this study conducted three-dimensional numerical simulations to investigate the effects of five key structural parameters, namely, the length of the nozzle diffuser section, the diameter of the nozzle outlet, the length of the contraction section in the mixing chamber, the diameter of the mixing chamber inlet, and the length of the mixing chamber throat, on the ejector performance under identical operating conditions. By fitting 50 sets of simulation data using the least squares method, analytical expressions for these structural parameters in terms of the ejection coefficient μ were obtained. Subsequently, an improved firefly algorithm was employed to identify the optimal combination of structural parameters, followed by simulation verification. The results showed that compared to the single-factor sensitivity analysis method, the improved firefly algorithm obtained a superior combination of structural parameters, resulting in a 2.03% enhancement in the ejection performance of the steam ejector.
Parallel active power filter based on single-phase independent control
Authors: Zhang Xun , Zhang Xiaoxiao , Wu Yuelin , Cao Bin , Yue Wenyan , Li Yao
Published: January 2024

With the rapid development of high-voltage power grids and power electronics technology, the integration of numerous power electronic devices has led to a significant increase in harmonic pollution in power grids. Consequently, the demand for high-voltage and large-capacity active power filters has become increasingly urgent. This article introduces a novel approach using single-phase independent control and proposes a parallel active power filter based on magnetic flux compensation. This filter not only enhances power quality but also achieves three-phase decoupling control. It is specifically designed for medium and high-voltage three-phase three-wire power systems. Simulation experiments were conducted to validate the efficacy of the proposed active power filter, demonstrating its ability to effectively reduce the total harmonic distortion rate at the grid connection point and subsequently improve power quality.
Research on combustion process optimization of marine diesel engines based on dual-injector system
Authors: Liu Long , Wang Xinhao , Liu Dai , Mao Wure , Xiong Feng
Published: January 2024

Marine diesel engines are widely used with their strong power and mature technology. However, in recent years, the emphasis on environmental protection has made combustion pollutants the focus of attention, and the new regulations of the International Maritime Organization (IMO) and various countries have put forward new requirements and challenges for diesel engine combustion and emission performance. Due to the large size and large amount of circulating fuel injection, the incomplete mixing of fuel in the cylinder and the local violent combustion of high-power medium-speed marine diesel engines are important reasons for low thermal efficiency and high pollutant emissions. To achieve efficient and clean combustion of fuel in the cylinder, a dual-injector combustion system is designed on a dual-fuel engine basis, aiming to add a micro-injection before the central injection and provide positive in-cylinder flow and hot atmosphere for the atomized combustion of the central-injection fuel, so that the combustion in the cylinder is reasonably arranged, the thermal efficiency is improved and NOx emissions are reduced. The 3D simulation model was established by CFD software CONVERGE, and the physical model was calibrated according to the data of the pure diesel mode of the dual-fuel engine, and the influence of the small pilot-injection fuel volume on the development of spray and combustion in the cylinder at high and low load was analyzed. It was found that the small pilot-injection fuel volume at a high load had little effect on the atomization evaporation of the main-injection fuel and the hot atmosphere in the cylinder, so the improvement effect of combustion quality was not obvious, while the pilot-injection volume with the same pilot-injection capacity as high load relatively accounted for a large proportion at the low load with a small cycle injection volume. Without changing the injector specification settings of the original dual-fuel engine, the thermal efficiency was increased by 6.13% and the NOx generation was reduced by 22.42% by optimizing the injection timing, injection duration, and injection amount.
Chemical kinetic model of cross-reactions between toluene reference fuel and tetrahydrofuran
Authors: Lu Heng , Zhang Qingfeng
Published: January 2024

A chemical kinetic model was developed for a multicomponent gasoline surrogate consisting of Tetrahydrofuran (THF), iso-octane, n-heptane, and toluene, covering some cross-reactions. The mechanism included 1954 species and 7908 reactions. It was verified that the outcomes agreed with the experimental observations of each pure component and its diverse mixtures. The surrogates perform better in forecasting experimental values due to the THF. The impact of cross-reactions was discussed about the ignition delays. The research found two cross-reactions, one between alkyl peroxyl radicals and pure components and one between benzyl peroxyl radicals and pure components (Types 2 and 3, respectively). Of these, Type 2 affected deceleration, and Type 3 on acceleration. Cross-reactions could increase the sensitivity coefficient for OH sensitivity analysis, promoting CH3 and O2 to produce HCHO. Combined with PSR species profiles, olefins, CO, and HCHO were the main products of oxidation. However, SENKIN and PREMIX simulations did not find the effect of cross-reactions within the intermediates.
Research on the application technology of lead acid batteries for mining electric vehicles
Authors: Zhang Zhiyao , Zhou Dehua , Wang Zhiwei , Zhao Yuan , Guo Zhijun
Published: January 2024

As a power source, ordinary explosion-proof large-capacity lead-acid batteries have been widely used in underground explosion-proof lead-acid battery scrapers and support trucks, but there are some problems, such as too long charging time, the need to manually add distilled water regularly, and the inability to realize intelligent management. In this paper, the mine special valve-regulated lead-carbon lead-acid battery with capacitance characteristics is applied to the explosion-proof heavy-duty electric drive car, which can shorten the charging time to about 1/5 of that of the ordinary lead-acid battery and reduce the labor maintenance cost. Through multi-sensor fusion technology, an online monitoring and intelligent expert management system for the explosion-proof battery is constructed, which can remotely monitor the real-time state of the battery. It can find out the causes of battery failure, give an alarm in advance, and prolong the service life of the battery pack, which is conducive to the further popularization and use of underground electric-driven trackless rubber tires.