bluuebunny/crossref_metadata_2025 huggingface dataset:
Feature‐enhanced representation with transformers for multi‐view stereo
Authors: Xiang Lintao , Yin Hujun
Published: March 2024

Most existing multi‐view stereo (MVS) methods fail to consider global context information in the stage of feature extraction and cost aggregation. As transformers have shown remarkable performance on various vision tasks due to their ability to perceive global contextual information, this paper proposes a transformer‐based feature enhancement network (TF‐MVSNet) to facilitate feature representation learning by combining local features (both 2D and 3D) with long‐range contextual information. To reduce memory consumption of feature matching, the cross‐attention mechanism is leveraged to efficiently construct 3D cost volumes under the epipolar constraint. Additionally, a colour‐guided network is designed to refine depth maps at a coarse stage, hence reducing incorrect depth predictions at a fine stage. Extensive experiments were performed on the DTU dataset and Tanks and Temples (T&T) benchmark and results are reported.
Design and implementation in an Altera's cyclone IV EP4CE6E22C8 FPGA board of a fast and robust cipher using combined 1D maps
Authors: Djomo Alain Fanda , Tiedeu Alain , Fotsing Janvier
Published: March 2024

This paper proposes an image encryption algorithm based on combined 1D chaotic maps. First, a permutation technique was applied. It was then reorganized into 1D matrices along the rows and columns respectively, which were then shuffled by computing the substituted position indices to obtain the scrambled image. Subsequently, a method of confusion of the scrambled image was used through another generated data map, combined with random sub‐matrices for diffusion, then resulting in an encrypted image. Finally, the proposed cryptosystem was implemented in a single kernel platform developed using the Nios II Software Build Tools processor for Eclipse. A hardware architecture was designed using the Qsys‐built tool which is available in the Quartus II 13.0sp1 environment. The developed single‐core system was implemented using the Cyclone IV EP4CE6E22C8. Robustness evaluation of the cryptosystem was performed through security analysis tests such as histogram analysis, correlation coefficient, differential analysis, and key space analysis to prove that it is of good quality, efficient, fast, and successfully resisting brute force attacks. The hardware performance analysis was also carried out. Then the cryptosystem is compared with those in the literature both in the hardware and security performance aspects.
A low‐cost method for testing and analyzing the cervical range of motion
Authors: Zhang Xun , Xu Guanghua , Li Zejin , Teng Zhicheng , Zhang Xin , Zhang Sicong
Published: March 2024

Measurement of the cervical range of motion (CROM) is significant for early diagnosis of cervical spondylosis and determination of the severity of the disease. Aiming at the problem of convenient and continuous measurement of CROM and the reduction of the impact of data fluctuations, this paper proposes a low‐cost method for testing and analyzing CROM. This paper analyzes the correspondence between smartphone orientation sensor angle and CROM, obtains smartphone orientation sensing data, and uses the extreme‐point symmetric mode decomposition method by calculating the energy of the difference value to extract the adaptive global mean curve of the CROM data, and calculates the cervical ROM. The statistical analysis of the CROM test results is carried out. Results show that the method proposed can obtain the CROM including flexion and extension, lateral flexion, and rotation in a single measurement, which has the advantages of continuous measurement and low cost.
Quand l’imagerie accompagne la restauration d’œuvres picturales : le cas Soulages
Authors: Hébert Mathieu , Simonot Lionel , Bringier Benjamin , Thoury Mathieu , Hélou-de La Grandière Pauline
Published: March 2024

Enregistrer l’apparence des oeuvres d’art moderne est un enjeu majeur car celle-ci évolue dans le temps, et un défi qui exige le développement de nouveaux principes d’imagerie ou d’adapter les principes existants car la couleur n’est pas le seul attribut visuel exploité par les peintres : le brillant, le relief, la texture jouent aussi un rôle essentiel, en témoigne l’analyse en mars 2023 d’une toile de Pierre Soulages.
Reviving Ecological Environments: Strategies for AI and VR Applications in Immersive Cultural Exhibitions
Authors: Li Qianrong , Cao Dan
Published: March 2024

This research delves into the novel integration of artificial intelligence (AI)--powered virtual reality (VR) ecological simulations within immersive cultural exhibitions. It emphasizes these simulations' role in augmenting sensory engagement and eliciting more robust emotional responses from audiences. AI-driven ecological simulations can be effectively applied in immersive exhibition design to transform and enhance audience interactions and experiences on an emotional and sensory level. The study employs a multifaceted research methodology, encompassing a comprehensive literature review to establish a theoretical foundation, in-depth case study analyses for practical insights, and empirical data collection from online public sources to gauge current trends and audience reception. We found that underscores the profound potential of AI-driven VR ecological simulations. Enhance sensory and emotional engagement significantly, providing evidence of their efficacy in creating more compelling and memorable exhibition experiences. These insights lay the groundwork for future AI and VR technology applications in cultural exhibitions, highlighting the imperative for innovative and interactive approaches that seek to engage audiences in more meaningful and immersive ways.
Landscape Locality in Rural Cultural Space: Strategies for Protection and Development
Authors: Xu Tuokun , Zheng Wenjun
Published: March 2024

The rural cultural space, though enhanced by policies like rural revitalization, faces challenges such as weakened cultural inheritance, insufficient depth, and homogenous planning. This study, focusing on Ping'an Village in Longsheng County, Guangxi, utilizes local knowledge theory to analyze and address these issues. The aim is to propose a development strategy for improving the cultural space system, enhancing cultural potential, and refining the mechanism system. This research aspires to offer insights for the protection and development of cultural spaces in other villages.
Research on countermeasures of China’s Marine culture dissemination under the background of maritime power--Take Zhoushan City of Zhejiang Province as an example
Authors: Yu Yiwen , Chen Feng , Mao Jiadai , Le Huiqin , Li Lunan
Published: March 2024

The development of Marine cultural tourism is an important measure to promote the development of Marine economy under the background of maritime power. The report on the work of the 20th National Congress of the CPC emphasized speeding up the construction of a maritime power and promoting the dissemination and development of Marine culture. China's Marine culture is rich and diverse, but the coastal cities are faced with many problems in the actual dissemination process, such as the characteristics of Marine culture are not prominent, homogenization is serious, and integration construction is not formed. This paper starts with the current situation of Marine culture communication, analyses the existing practical experience and existing problems of Marine culture communication, and takes Zhoushan City, a famous coastal city in Zhejiang Province, as an example to discuss the countermeasures for the construction of China's Marine culture communication system under the background of maritime power, so as to promote the new development of Marine culture communication.
Food Factors: The Role of Nutritional Clarity in Enhancing Public Health Outcomes
Authors: Chen Xiaojiao , Li Xinqing
Published: March 2024

In the milieu of modern food consumption, public health is beleaguered by the prevalence of processed foods and a dearth of clear nutritional information, factors that are intimately linked to the surge of global health issues. Our exploration into the interplay between food labeling, dietary education, regulatory policies, and community interventions reveals a complex landscape where each element is critical to steering public health toward a more nutritious future. Through a synthesis of multi-disciplinary research and pragmatic case studies, we dissect the efficacy of current nutritional transparency practices and propose a suite of actionable strategies aimed at catalyzing improvement. We argue for the necessity of a robust, unified approach where policy reform, comprehensive education, and grassroots empowerment converge to enact substantive change. This article posits that such a collaborative and systemic endeavor is not merely beneficial but imperative for engendering informed dietary choices, mitigating the tide of nutrition-related diseases, and ultimately sculpting a framework for sustained public health advancement. Our findings illuminate the potential for significant public health outcomes through concerted action and suggest that the path to a healthier society is paved by the collective efforts of policymakers, educators, and community advocates working in tandem to combat the complexities of the contemporary food environment.
How are elite female athletes framed on China’s mainstream media: The case of Li Na
Authors: Wang Boyan
Published: March 2024

Sport is a male-dominated field where female athletes are relatively marginalized. This article applies the theory of framing to explore how a high-profile female athlete --Li Na-- is trivialized by the coverage of China’s mainstream media. The analysis reveals that stereotypical feminine roles, individualism and collectivism, and nationalism are common aspects regularly emphasized by media to undermine Li Na’s athletic achievement.
Exploring the Art of Guqin
Authors: Xu Jiayi
Published: March 2024

This paper is based on the history of Guqin art and employs a chronological approach to examine various aspects such as players, music, and tablature throughout different periods. By outlining the historical development of Guqin art, it prompts contemplation on the contemporary inheritance and development of Guqin art. This paper presents four proposed ideas for the inheritance and development of Guqin art, which include establishing a professional Guqin teaching system, emphasizing the study of Guqin tablature notation techniques, strengthening the popularization of Guqin art among the general public, and addressing the new challenges faced by Guqin art in the present. The author believes that aligning Guqin art with the modern era is an inevitable trend in its artistic development.
An Appreciation of the First Movement of Mozart’s Piano Sonata in D Major, KV.576
Authors: Wang Le
Published: March 2024

The most outstanding and influential composer of the Viennese classical school is Mozart, and the Piano Sonata in D Major (KV.576) is Mozart's last sonata, written in 1789. This paper will mainly focus on the first movement of KV.576, analysing it in detail from the compositional background, the period background, the performance technique, and the perception of the performance. KV.576 achieves balance and harmony by contrasting composition, theme, and texture. Instead of following the traditional style, Mozart's music reinterprets the new music with the vocabulary of the time to realize the aesthetic ideal of classical music.
Eclecticism and Unity in Diversity – Analysing the integration and application of modern technology in theatre arts
Authors: Li Dongyao
Published: March 2024

In today's rapid development of science and technology, almost every aspect of our life has a very close relationship with modern technology, especially in the creation of art is more and more inseparable from the aid of modern technology. As a large branch of artistic creation, stage art design is a comprehensive art, involving scene design, lighting, sound effects, costumes, make-up, props, special effects and many other aspects of its more inclusive. This paper starts from the use of modern science and technology in stage art design, and analyses how stage art design can be unified under the diverse and pluralistic forms of expression.
Immunologische Tracerentwicklung mit Nanobodies
Authors: Küppers Jim
Published: March 2024

Nanobodies sind die antigenbindenden Fragmente eines speziellen Antikörperformats, welches
zum Beispiel in Kameliden vorkommt. Die Größe, Struktur und Beschaffenheit von Nanobodies
bringen viele Vorteile mit sich, wodurch sie als exzellente Vehikel für die Entwicklung von
Radiotracern in der nuklearmedizinischen Bildgebung und Therapie von großem Wert sind. Zu
diesem Zweck werden die entsprechenden Radiohalogene oder Radiometalle auf unterschiedliche
Art und Weise selektiv oder unselektiv an der Peptidkette des Nanobody’s angebracht. Die
indirekte Radiohalogenierung mittels prosthetischer Gruppen und die Postmarkierung von bereits
eingebrachten Chelatoren mit Radiometallen sind die bevorzugten Markierungsstrategien. Am
häufigsten erfolgt die Tracerentwicklung über den His6-Tag mit
99mTc-Tricarbonyl. Präklinisch und auch zum Teil klinisch konnte die Eignung von
verschiedenen nanobodybasierten Tracern bereits gezeigt werden.
Ein Recht auf humanitäre Versorgung für alle – AAAQ-Framework
Authors: Hertl Annika
Published: March 2024

Jeder Mensch hat ein Recht auf den Zugang zu medizinischer Versorgung – dies ist ein Grundsatz der Weltgesundheitsorganisation WHO. Sie entwickelte das AAAQ-Framework, das anhand der Komponenten Availability, Accessibility, Acceptability und Quality als Hilfsmittel dabei unterstützt, die Gesundheit betreffende Strukturen zu erfassen und zu reflektieren.
Let’s WOOP – Zielerreichung mit der WOOP-Methode
Authors: Müller Julia
Published: March 2024

Obwohl wir uns etwas fest vornehmen, scheitern wir oft am kontinuierlichen Verfolgen eines Zieles. Dann kann die von Gabriele Oettingen entwickelte WOOP-Methode helfen, bei der man sich folgende vier Komponenten vor Augen führt und reflektiert: Wish, Outcome, Obstacle und Plan.
Wirksamer Vorhernachher-Effekt – Raumgestaltung in der Tagesklinik
Authors: Möller Jasmin , Denecke Cord Eike
Published: March 2024

Einige Patient*innen mit einer psychiatrischen Erkrankung möchten üben, mit anderen Menschen in Kontakt zu treten. Andere wiederum benötigen beispielsweise eine klientenzentrierte Unterstützung auf ihrem Weg ins Berufsleben. Die Tagesklinik Blankenburg hat ihren Arbeitstherapie-Bereich weiterentwickelt, um den Bedürfnissen der Patient*innen und den Anforderungen der digitalen Welt gerecht zu werden.
Mobil bleiben – Offroad-Rollator E-hiker
Authors: Mischner Julia
Published: March 2024

Gerhart Wissel ist 92 Jahre alt und nach einem Fahrradunfall in seiner Mobilität eingeschränkt. Um weiterhin in der Natur unterwegs sein zu können, entwickelte er ein geländetaugliches Wandergerät mit E-Antrieb, den sogenannten WisselAlpin E-hiker.
Reduction en masse of Inguinal Hernia in a 2-Month-Old Male Infant
Authors: Kojima Masato , Touge Ryo , Kurihara Sho , Saeki Isamu , Takahashi Shinya
Published: March 2024

Reduction en masse is the reduction of the hernial sac into the preperitoneal space, with a loop of bowel remaining trapped at the neck of the hernial sac. This complication is rare, usually associated with inguinal hernias, and is characterized by the absence of a noticeable bulge in the groin. The patient was a 2-month-old male infant and presented with a nonreducible bulge in his left groin, and incarceration of the left inguinal hernia was diagnosed. Manual reduction was performed, and the hernia bulge became less noticeable. He was admitted, and laparoscopic percutaneous extraperitoneal closure was scheduled for the next day. The laparoscopy revealed remarkably dilated intestines, serous ascites, and an ischemic intestine in the left groin. A laparotomy was performed and revealed reduction en masse of the left inguinal hernia with a strangulated ileum at its neck. We made an incision at the neck, followed by the resection of 20-cm long strangulated ileum. The patient's condition was unstable on the day of operation, but the postoperative period was uneventful, and the left inguinal hernia was repaired, 11 months after the operation. Reduction en masse in pediatrics is significantly rare but when it occurs, the diagnosis can be delayed and occasionally the patient will be life-threatening. To avoid reduction en masse, it is crucial to perform the reduction gently and confirm the absence of a hernia sac in the preperitoneal space containing a loop of bowel by ultrasound scanning. Moreover, contrary to common practice, overnight observation and close monitoring will avoid missing a late presentation, leading to timely interventions.
Intraoperative Stimulation Mapping in Neurosurgery for Anesthesiologists, Part 2: The Anesthetic Considerations
Authors: Masohood Naeema S. , Paquin-Lanthier Gabriel , Chui Jason , Lu Nancy , Chowdhury Tumul , Venkatraghavan Lashmi
Published: March 2024

Intraoperative language and sensorimotor function mapping with direct electrical stimulation allows precise identification of functionally important brain regions. Direct electrical stimulation brain mapping has become the standard of care for the resection of brain lesions near or within eloquent regions with various patient outcome benefits. Intraoperative stimulation mapping (ISM) is commonly performed in an awake patient for language and motor assessments. However, motor mapping under general anesthesia, termed asleep motor mapping, has been increasingly performed over the last two decades for lesions primarily affecting the motor areas of the brain. Both asleep-awake-asleep and monitored anesthesia care have been successfully used for awake craniotomy in modern neuroanesthesia. Each anesthetic agent exerts varying effects on the quality of ISM, especially under general anesthesia. Careful selection of an anesthetic technique is crucial for the successful performance of ISM in both awake and asleep conditions. A comprehensive search was performed on electronic databases such as PubMed, Embase, Cochrane, Scopus, Web of Science, and Google Scholar to identify articles describing anesthesia for awake craniotomy, intraoperative brain mapping, and asleep motor mapping. In the second part of this narrative review, we summarize the effects of different anesthetic regimes and agents on ISM, causes of the failure of awake craniotomy and mapping, and outline the anesthetic considerations for ISM during awake craniotomy and asleep motor mapping.
Radical and quantum interference-enhanced thermoelectric performance of the junctions based on porphyrin dimer molecules
Authors: Huang Lin , Wang Jue , Chen Tong , Xu Liang , Ning Feng , Wu Dan , Chen Ke-Qiu
Published: March 2024

Manipulating the π-electron magnetism of single-molecule junctions is an effective means to improve the electronic and spin-polarized thermoelectric transport properties. Here, using the density functional theory combined with the nonequilibrium Green's function method, we demonstrate that the electronic conductance (σ) of molecular junctions (MJs) can be significantly enhanced by organic radicals due to the shifting of resonant states. Moreover, we find that the spin-dependent quantum interference (SDQI) effects can be largely influenced by organic radicals. The SDQI effects result in nearly 100% spin filtering efficiency in open-shell molecules and greatly enhance the Seebeck coefficients. As a result, the thermoelectric performances of open-shell MJs at room temperature are greatly improved through the combined effects of radicals and SDQI. In particular, the maximum ZTsp in the four radical junctions reaches up to 36.5. Our results show great potential for improving thermoelectric performance through the utilization of quantum interference and organic radical.
On the logarithmic nature of axial dispersion in Darcy flow through heterogeneous porous media
Authors: Huygens Bram , Desmet Gert
Published: March 2024

The present study provides novel insights in how spatial velocity variations in a heterogeneous porous medium cause the dispersion of a passive tracer. The study consists of two parts. The first part describes a series of numerical computations of the axial dispersion in the flow through heterogeneous porous media, idealized as Darcy flow through two-dimensional and three-dimensional patchwork geometries of zones with randomized permeability fields. Data on the axial dispersion were obtained using the mean age theory, which transforms the transient advection–diffusion equation into the steady-state mean age field equation, thus reducing the required computational effort by multiple orders of magnitude. This allowed to consider a sufficiently large number of randomizations to obtain a statistically representative ensemble average, as well as to consider sufficiently large systems to reduce the influence of boundary conditions. In the second part, it is shown that the relation between the axial dispersion coefficient and the velocity can be represented as a series, summing up the effect of velocity differences on all length scales, assuming the velocity differences are analogous to white noise. The sum can be closely fitted by a logarithmic law containing only two parameters with a well-defined physical meaning. A similar logarithmic dependency was also obtained by Saffman, Koch, and Brady. However, the logarithmic dependency obtained in the present work emerges from the heterogeneity of the porous medium, whereas the logarithmic dependency in the aforementioned works emerged from the no-slip boundary conditions at solid surfaces.
Nanopatterning of Si surfaces by normal incident He plasma irradiation
Authors: Liu Zhe , Li Long , Gao Zeshi , Chen Ze , Yin Chao , Mao Shifeng , Kajita Shin , Ohno Noriyasu , Ye Minyou
Published: March 2024

This study reports on the formation of self-organized silicon (Si) nanostructures by 75 eV helium (He) plasma irradiation at normal incidence without the presence of impurities. In contrast to the featureless surface after normal incidence argon (Ar) ion beam irradiation without the co-deposition of impurities, the Si surface exhibits the development of faceted nanostructures under 75 eV He plasma irradiation. The faceted structures are interspersed with valleys that extend in two orthogonal directions, imparting a mountain-like morphology to the surface. Our investigation verifies that the He bubbles align themselves along the direction perpendicular to the surface underneath these valleys. Furthermore, the presence of He bubbles induces distortion in the surface layer and leads to the formation of an amorphous Si layer. The underlying mechanism driving this surface evolution could be attributed to the instability induced by the presence of He bubbles.
Coherent control of magnetization precession by double-pulse activation of effective fields from magnetoacoustics and demagnetization
Authors: Mattern M. , Weber F.-C. , Engel D. , von Korff Schmising C. , Bargheer M.
Published: March 2024

We demonstrate the coherent optical control of magnetization precession in a thin Ni film by a second excitation pulse, which amplifies or attenuates the precession induced by a first pulse depending on the fluences of the pump-pulses and the pump-pump delay. This control goes beyond the conventional strategy, where the same mechanism drives the precession in-phase or out-of-phase. We balance the magneto-acoustic mechanism driven by quasi-static strain and the shape-anisotropy change triggered by laser-induced demagnetization. These mechanisms tilt the transient effective magnetic field in opposite directions in the case of negative magneto-elastic coupling (b1<0). While the strain response is linear in the fluence, demagnetization is nonlinear near the Curie temperature, enabling fluence-based control scenarios.
Enhanced robustness against hot-electron-induced degradation in active-passivation p-GaN gate HEMT
Authors: Yang Junjie , Wei Jin , Wu Yanlin , Yu Jingjing , Cui Jiawei , Yang Xuelin , Liu Xiaosen , Wang Jinyan , Hao Yilong , Wang Maojun , Shen Bo
Published: March 2024

The hot-electron-related reliability is an important issue for GaN power devices under harsh operation condition or environment. These high-energy electrons can scatter toward the device surface or buffer layer, introducing newly generated traps/defects and resulting in the degradation of dynamic ON-resistance (RON). This work investigates the dynamic characteristics in active-passivation p-GaN gate HEMTs (AP-HEMTs) after hot-electron stress (HES). Unlike the dielectric passivation whose dynamic RON performance is often reported to severely worsen as hot-electron-induced defects/traps accumulate, the active passivation is found to have a superior robustness against hot-electron stress. In this study, after an HES of 30 min with VD = 200 V and IS = 10 mA/mm, the dynamic RON/static RON of a conventional HEMT increases dramatically from 3.63 to 9.35 for VDS-OFF = 650 V, whereas that of AP-HEMT only shows a slight increase from 1.51 to 1.85. Two mechanisms have been experimentally proved for the improved hot-electron robustness in AP-HEMT. (i) The mobile holes in active passivation layer can effectively screen the preexisting and/or newly generated surface defects/traps from affecting the 2DEG channel. (ii) The recovery of buffer trapping is accelerated by hole injection from gate and active passivation.
Highly efficient stimulated Raman scattering at the air–heavy water interface
Authors: Dou Zhenguo , Li Chengqi , Sun Chenglin , Fang Wenhui , Men Zhiwei
Published: March 2024

In this study, we conducted a detailed exploration of stimulated Raman scattering (SRS) in heavy water (D2O), focusing specifically on its behavior at the air–D2O interface. The analysis revealed discernible SRS characteristic peaks corresponding to different vibrational modes, showing a 3.31-fold reduction in the SRS threshold at the air–D2O interface. Notably, we achieved a remarkable 6.83% energy conversion efficiency, approximately 3.36 times higher than the 2.03% efficiency observed in bulk D2O. Through cascaded Raman scattering and Raman-enhanced four-wave mixing (FWM) processes, up to third-order Stokes and corresponding anti-Stokes SRS were obtained in an unprecedented manner at a low pump energy of 8.26 mJ. Additionally, distinctive conical spatial structures of Stokes and anti-Stokes generated at air–D2O interface were attributed to Raman-enhanced FWM processes. Our investigation into the temporal behavior of SRS pulses revealed a unique mechanism: the initial decline of pump pulse was due to SRS-induced pump energy loss and heat dissipation, while the behavior of latter half resulted from non-uniform refractive index, causing self-defocusing and inhibiting the sustained generation of SRS. Our study sheds light on the development of multi-wavelength and significant frequency shift Raman lasers, offering valuable perspectives for future research endeavors.
Flow resistance of phloem sieve plates revisited using an experimental model
Authors: Sevanto Sanna
Published: March 2024

Sieve plate resistance has been identified as the key to understanding the efficiency of phloem transport of carbohydrates in trees. These plates with small holes connecting sieve tubes are responsible for the largest resistance to flow in the phloem. Their structure determines how fast sugars can be transported through the phloem with certain pressure differences and what the limits for phloem transport in different plants are. Because experiments with the phloem are very challenging, our understanding of sieve plate resistance is mostly based on anatomical studies and hydrodynamic modeling of flow through sieve plates. These models calculate the resistance of the entire sieve tube–sieve plate system using the Hagen–Poiseuille flow resistance for the sieve cell lumen and a combination of the Hagen–Poiseuille resistance and Sampson flow resistance through the sieve pores. The resistance of the entire sieve plate is calculated by summing the Hagen–Poiseuille and Sampson flow resistances of each pore. To test the validity of this model formulation, an experimental model with aspect parameters similar to phloem sieve tubes was built using polyvinyl chloride (PVC) piping and plastic straws of different diameters and lengths. This system was used to measure flow rates and calculate flow resistance at Reynolds numbers 0.5–300. The results suggest that the current models may significantly overestimate the flow resistance caused by sieve plates and that the resistance might be better described by formulations used for perforated plates.
Methane catalytic cracking by solid materials and molten media for hydrogen production: A review
Authors: Guo Lei , Tan Jinchi , Ren Junyue , Guo Zhancheng
Published: March 2024

Excessive emission of carbon dioxide is the leading cause of global warming. Hydrogen has the advantages of high calorific value and zero carbon emissions. It is considered an ideal energy to solve the problem of global warming, so the demand for hydrogen is increasing yearly. Due to economic considerations, methane is the main raw material for hydrogen production. Currently, 48% of the world's hydrogen comes from steam methane reforming. However, this process needs to burn some methane for heating, generating carbon dioxide emissions simultaneously. In order to avoid carbon emissions from hydrogen production, there is an urgent need to develop new methods to produce hydrogen from methane. Because the carbon generated from direct methane cracking exists in solid form while not as carbon dioxide, the direct methane cracking process for hydrogen production has become a hot research topic in recent years. In this paper, a comprehensive review of the research related to catalytic methane cracking for hydrogen production is presented, especially the research on catalytic cracking of methane using solid materials or molten metal media as catalytic media is summarized in detail. Next, a brief overview of the mechanism of catalytic methane cracking for hydrogen production and the characteristics of the generated carbon as a by-product are presented. Finally, the catalytic cracking of methane in molten media or solid materials and the research trend were prospected.
Investigation of the large-signal electromechanical behavior of ferroelectric HfO2–CeO2 thin films prepared by chemical solution deposition
Authors: Lübben Jan , Berg Fenja , Böttger Ulrich
Published: March 2024

In this work, the piezoelectric properties of chemical solution deposition derived ferroelectric HfO2–CeO2 thin films deposited on platinized silicon substrates are investigated. Large-signal strain-field measurements show an effective piezoelectric coefficient of approximately d33,eff=12.7pm/V for 17 mol. % cerium under bipolar excitation and d33,eff=8pm/V under unipolar excitation. Progressive bipolar electric field cycling leads to a reduction in the overall field induced strain although no fatigue with regards to the polarization is observed. To explain this, we propose a model explanation based on changes in the polarization reversal pathway from a primarily ferroelastic, i.e., 90° domain wall mediated switching, to a 180° type switching. Furthermore, unipolar strain-field measurements reveal a negative intrinsic piezoelectric coefficient in the absence of any ferroelastic contribution, confirming theoretical predictions. The results suggest that the ferroelastic contribution to the field-induced strain needs to be stabilized in Hafnia-based ferroelectric materials to make them more feasible for micro-electromechanical systems.
Statistical analysis of locked mode induced disruption in EAST
Authors: Zhou Wei-Ran , Deng Guo-Hong , Sun You-Wen , Wang Hui-Hui , Zhou Deng , Shi Tong-Hui , Gu Shuai , Ye Cheng , Ma Qun , Zang Qing , He Kai-Yang , Chen Da-Long , Shen Biao , Jia Man-Ni , Luo Zheng-Ping , Liu Hai-Qing , Zhou Zi-Qiang , Zhang Tao
Published: March 2024

The effects of key parameters on locked mode induced disruption (LMiD) are investigated in EAST experiments. The experimental data for locked mode are collected from 2015 to 2022 when the externally applied resonant magnetic perturbation is successfully employed in EAST. In this dataset, ∼42% of the total shots are LMiD, while the remaining 58% are LM without disruption. To better analyze the LMiD, an intuitive physical process is proposed. The LMiD process can be divided into two stages, the evolution of magnetic islands and the loss of plasma stored energy. The LMiD can also be related to the evolution of the other 8 physical quantities. On the basis of this physical process analysis, the time scale and the influencing factors for LMiD are investigated using statistical analysis. It is found that the density (ne), the distance from the magnetic island outer boundary to the plasma last closed surface (dedge), the loop-voltage (Vloop), and the plasma core electron temperature (Te), which are consistent with the intuitive physical model, are key parameters to LMiD. In addition, other potentially important parameters, the relevant reasons, and statistical analysis on the parameter intervals where rapid disruption with greater harmfulness occurred have also been investigated.
Numerical analysis of COVID-19 model with Caputo fractional order derivative
Authors: Shahabifar Reza , Molavi-Arabshahi Mahboubeh , Nikan Omid
Published: March 2024

This paper focuses on the numerical solutions of a six-compartment fractional model with Caputo derivative. In this model, we obtain non-negative and bounded solutions, equilibrium points, and the basic reproduction number and analyze the stability of disease free equilibrium point. The existence and uniqueness of the solution are proven by employing the Picard–Lindelof approach and fixed point theory. The product–integral trapezoidal rule is employed to simulate the system of FODEs (fractional ordinary differential equations). The numerical results are presented in the form of graphs for each compartment. Finally, the sensitivity of the most important parameter (β) and its impact on COVID-19 dynamics and the basic reproduction number are reported.
Composition dependence of anomalous Nernst effect in amorphous TbFeCo thin films with perpendicular magnetic anisotropy
Authors: Ando Ryo , Komine Takashi
Published: March 2024

In this study, we systematically investigated the anomalous Nernst effect in perpendicularly magnetized amorphous TbFeCo thin films with various compositions. It was found that the magnitude of the off diagonal thermopower (ODT), which corresponds to the anomalous Nernst effect, can be uniformly explained with respect to the Tb content regardless of the concentration above or below the compensation composition. The maximum ODT of 1.3 μV/K and the thermoelectric conductivity of 1.59 A/mK at room temperature were obtained, which is more significant than other perpendicular magnetic anisotropy thin films to achieve a large Nernst voltage for roll-type thermoelectric devices. By considering the thermoelectric tensor, Mott’s equation, and the scaling law, it was shown both experimentally and theoretically that the magnitudes of the first and second terms contributing to the anomalous Nernst effect are comparable. It was also found that the ODT of TbFeCo thin films is twice or more significant than the product of the Seebeck coefficient and the Hall angle. Furthermore, amorphous metals and Mn-alloys with a large Berry curvature are located above the relation that the ODT is twice the product of the Seebeck coefficient and the Hall angle, which means that amorphous metals are expected to enhance the ANE.
Increasing the Q-factor of resonant cantilevers in magnetic force microscopy through helium gas flow
Authors: Abas Asim , Geng Tao , Meng Wenjie , Touqeer Muhammad , Esmaeilzadeh Behnam , Feng Qiyuan , Wang Ze , Yubin Hou , Lu Qingyou
Published: March 2024

To obtain high-resolution magnetic force microscopy (MFM) images, it is essential to have a cantilever with a high-quality factor. However, conventional vibrating cantilevers typically have quality factor values in the range of a few hundred, which limits their sensitivity for MFM measurements. To address this limitation, numerous studies have explored methods to enhance the quality factor in different environments, including vacuum, air, and liquid. This study introduces a novel approach for improving the quality factor using flowing helium gas. By selecting helium gas with a low viscosity coefficient, we successfully achieved a higher quality factor (Q-factor) of MFM microcantilever oscillations at room temperature in one atmosphere compared with the Q-factor in air. This provides a potential approach for achieving high-resolution MFM measurements under room temperature conditions. By optimizing the gas flow rate at room temperature in one atmosphere, we successfully obtained a higher MFM cantilever oscillation Q-factor and clearer MFM images compared with the air. The experimental results revealed a long and narrow resonant curve, and the quality factor significantly increased to 778.2, which is 3.8 times higher than that observed in air 205.4. Furthermore, systematic investigations demonstrated the capability of this approach to produce high-resolution MFM images of videotape track patterns under the optimized helium gas flow rate of 60 mm/s.
Multiscale modeling and simulation of turbulent flows in porous media
Authors: Jin Yan , Kuznetsov Andrey V.
Published: March 2024

Numerical simulation is an important tool for understanding the physics of flows in porous media and for making predictions. The state of the art of multiscale modeling and simulation of turbulent flows in porous media is reviewed in this paper. Numerical simulations of flows in porous media can be classified as microscopic simulations, in which both macroscopic and pore-scale flows are directly resolved, and macroscopic simulations, in which the pore-scale motions are modeled while the volume-averaged equations are solved. Studies in the past few years have shown that microscopic simulations improve the understanding of turbulent flows in porous media considerably; this motivates the development of more efficient and more accurate turbulence models for macroscopic simulations. On the basis of this review, we believe that simulation of flows with higher Reynolds numbers, understanding the transport of macroscopic turbulence, modeling of turbulent flows in inhomogeneous and anisotropic porous media, simulation of compressible and multiphase turbulent flows in porous media, and fluid–structure interaction in deformable porous matrices are important topics to be studied in the future.
Enhanced thermoelectric properties of layered anisotropic PbBi2Te4 through the suppression of bipolar diffusion effect via Se alloying
Authors: Qian Xin , Jin Hehui , Li Xuefei , Ding Bangfu , Wang Jianglong , Wang Shu-Fang
Published: March 2024

The layered ternary PbBi2Te4 is regarded as a promising thermoelectric material due to its intricate crystal structure. However, current research on PbBi2Te4 primarily focuses on theoretical calculations and predictions, with limited investigations conducted on its actual thermoelectric transport properties. In this study, we synthesized the single-phase PbBi2Te4 compound using the high-temperature melting method. The research findings indicate that PbBi2Te4 exhibits significant anisotropic thermoelectric properties and a pronounced bipolar diffusion effect, which can be attributed to its unique layered crystal structure and relatively narrow bandgap. This bipolar diffusion effect remarkably exacerbates the Seebeck coefficient of PbBi2Te4 and amplifies its thermal conductivity. To address these challenges, we effectively manipulated the electronic band structure of PbBi2Te4 and enlarged the bandgap through the incorporation of Se alloying. The thermoelectric performance of PbBi2Te4 has been significantly enhanced as a result of the increase in Seebeck coefficient and reduction in thermal conductivity. Ultimately, a superior ZT value of ∼0.52 at 673 K is achieved in PbBi2(Te0.85Se0.15)4, representing an impressive improvement of ∼ 49% compared to the pure PbBi2Te4. These results demonstrate the promising potential of ternary PbBi2Te4 as a thermoelectric material.
Nitrogen atoms absolute density measurement using two-photon absorption laser induced fluorescence in reactive magnetron discharge for gallium nitride deposition
Authors: Srinivasan Lakshman , Invernizzi Laurent , Prasanna Swaminathan , Gazeli Kristaq , Fagnon Nicolas , Roca i Cabarrocas Pere , Lombardi Guillaume , Ouaras Karim
Published: March 2024

Low-pressure plasmas, in particular magnetron sputtering discharges, are increasingly used for the deposition of wideband gap semiconductor nitrides films (e.g., GaN or AlN) considering many benefits they exhibit with respect to conventional chemical vapor deposition techniques. Plasma-based solutions enable the dissociation of N2 molecules into N-atoms under conditions that would not be possible with the thermal process. However, as the dissociation rate remains quite small due to the strong nitrogen triple bond, it is somewhat complicated to determine and correlate the N-atoms density in the gas phase with that of the grown film in low-pressure discharges. Therefore, ns-two-photon absorption laser induced fluorescence (TALIF) has been carried out to determine the absolute density of N-atoms as a function of the pressure (tens of Pa range) in a radio-frequency sputtering plasma reactor used for GaN deposition. The TALIF set-up has been optimized using a monochromator and adequate signal processing to enhance the detection limit, enabling the measurement of N-atoms density as low as 1011 cm−3 at 15 Pa. These measurements have been completed with electron density measurements performed in the same pressure range using microwave interferometry, thus providing quantitative data on both electron and N-atom densities that can be used for fundamental understanding, process optimization, and modeling of magnetron discharge intended for nitride semiconductor deposition.
Evidence for ionization damage in mid-wave infrared nBn detectors
Authors: Logan J. V. , Webster P. T. , Helms L. , Grant P. C. , Hains C. , Carrasco R. A. , Newell A. T. , Alsaad Z. , Maestas D. , Morath C. P.
Published: March 2024

The effects of 63 MeV proton and 60Co gamma irradiation on the operation of 4.3 μm cutoff nBn photodetectors are demonstrated separately, and both are shown to yield a total ionizing dose (TID) effect. The effect is shown here in an InAsSbBi nBn detector and has been observed in other bulk alloy nBn detectors, and is unusual as it is notably absent in superlattice nBn detectors. The non-antireflection coated detectors exhibit a pre-radiation quantum efficiency of 17% at 3.3 μm wavelength and a dark current density of 50 μA/cm2, or roughly 300× the Rule 07 expectation, at their ideal operating voltage of −0.4 V bias at 150 K. Step-wise proton irradiation and in situ measurement indicate that the dark current increases to about 400× Rule 07 at the highest proton dose level of 150 krad(Si) (9.10 × 1011 p+/cm2), while the quantum efficiency is degraded at a relatively faster rate than the majority of analogous detectors characterized by our lab. Both the photocurrent and dark current are also shown to exhibit a turn-on voltage magnitude reduction of 100 mV following either gamma or proton irradiation, a trend which is attributable to negative trapped charge at the barrier interface (TID effect). This theory is further supported by an observed capacitance density magnitude reduction with dose and affirmed with Silvaco TCAD simulations. Following both proton exposure and subsequent anneal and gamma exposure and subsequent anneal; dark current, photocurrent, and CV all approach their pre-radiation baseline values.
Numerical study of a laminar vortex ring of a polymer solution
Authors: Yuan Chenguang , Xu Duo
Published: March 2024

In this study, we investigate the laminar vortex ring of the polymer solution in numerical simulations. We examine the flow structure of the vortex core and the evolution of the vortex ring, with comparison with those of the Newtonian vortex ring. The advection speed of the solitary vortex ring of the polymer solution is found to decrease with time, following an approximate power scaling, similar to that of the Newtonian vortex ring. The dependence of this power scaling on the polymer viscosity ratio and the Weissenberg number of the flow is examined. The power scaling decreases as the polymer viscosity ratio is increased or the Weissenberg number is decreased. The similar scenario is also observed for the circulation of the solitary vortex ring.
Settling dynamics and thresholds for breakup and separation of bi-disperse particle clouds
Authors: Hu Jianxin , Yin Qilei , Xie Jiafeng , Su Xianghui , Zhu Zuchao , Pan Dingyi
Published: March 2024

The gravity-driven settlement process of bi-disperse particle clouds is investigated by using a computational fluid dynamic–discrete element method coupled model. The purpose of this work is to discuss the effect of particle size ratio and cloud size on cloud settling, with an emphasis on cloud morphological changes and dynamic mechanisms, as well as the spatial distribution and movement rules of each dispersed phase. The simulation results demonstrate that the settling of bi-dispersed clouds is accompanied by cloud breakup and the separation of large and small particles. The rise in particle size ratio will make cloud breakup more difficult, and the increase in cloud size facilitates the separation of large and small particles in the cloud. Essentially, cloud breakup and separation are closely related to weak inter-particle forces, and the thresholds for these two events are, respectively, proposed. Decomposable clouds will continuously flatten into toruses before breaking up, with an increasing aspect ratio γ that suggests a weakening of the interactions. When the aspect ratio exceeds a critical value of 2, the cloud breaks up. The non-dimensional distance ld* between large and small particles, describing the interaction between two dispersed phases, correlates with their separation. The critical distance for separation is 29. Furthermore, the sequence in which the two critical conditions are met determines the order in which cloud breakup and particle separation take place.