bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual-shot dynamics and ultimate frequency of all-optical magnetic recording on GdFeCo
Authors: Wang Sicong , Wei Chen , Feng Yuanhua , Cao Hongkun , Li Wenzhe , Cao Yaoyu , Guan Bai-Ou , Tsukamoto Arata , Kirilyuk Andrei , Kimel Alexey V. , Li Xiangping 
Published: January 2021

AbstractAlthough photonics presents the fastest and most energy-efficient method of data transfer, magnetism still offers the cheapest and most natural way to store data. The ultrafast and energy-efficient optical control of magnetism is presently a missing technological link that prevents us from reaching the next evolution in information processing. The discovery of all-optical magnetization reversal in GdFeCo with the help of 100 fs laser pulses has further aroused intense interest in this compelling problem. Although the applicability of this approach to high-speed data processing depends vitally on the maximum repetition rate of the switching, the latter remains virtually unknown. Here we experimentally unveil the ultimate frequency of repetitive all-optical magnetization reversal through time-resolved studies of the dual-shot magnetization dynamics in Gd27Fe63.87Co9.13. Varying the intensities of the shots and the shot-to-shot separation, we reveal the conditions for ultrafast writing and the fastest possible restoration of magnetic bits. It is shown that although magnetic writing launched by the first shot is completed after 100 ps, a reliable rewriting of the bit by the second shot requires separating the shots by at least 300 ps. Using two shots partially overlapping in space and minimally separated by 300 ps, we demonstrate an approach for GHz magnetic writing that can be scaled down to sizes below the diffraction limit.
Direct quantification of topological protection in symmetry-protected photonic edge states at telecom wavelengths
Authors: Arora Sonakshi , Bauer Thomas , Barczyk René , Verhagen Ewold , Kuipers L. 
Published: January 2021

AbstractTopological on-chip photonics based on tailored photonic crystals (PhCs) that emulate quantum valley-Hall effects has recently gained widespread interest owing to its promise of robust unidirectional transport of classical and quantum information. We present a direct quantitative evaluation of topological photonic edge eigenstates and their transport properties in the telecom wavelength range using phase-resolved near-field optical microscopy. Experimentally visualizing the detailed sub-wavelength structure of these modes propagating along the interface between two topologically non-trivial mirror-symmetric lattices allows us to map their dispersion relation and differentiate between the contributions of several higher-order Bloch harmonics. Selective probing of forward- and backward-propagating modes as defined by their phase velocities enables direct quantification of topological robustness. Studying near-field propagation in controlled defects allows us to extract upper limits of topological protection in on-chip photonic systems in comparison with conventional PhC waveguides. We find that protected edge states are two orders of magnitude more robust than modes of conventional PhC waveguides. This direct experimental quantification of topological robustness comprises a crucial step toward the application of topologically protected guiding in integrated photonics, allowing for unprecedented error-free photonic quantum networks.
Therapeutic targeting of TGF-β in cancer: hacking a master switch of immune suppression
Authors: van den Bulk Jitske , de Miranda Noel F.C.C. , ten Dijke Peter 
Published: January 2021

AbstractCancers may escape elimination by the host immune system by rewiring the tumour microenvironment towards an immune suppressive state. Transforming growth factor-β (TGF-β) is a secreted multifunctional cytokine that strongly regulates the activity of immune cells while, in parallel, can promote malignant features such as cancer cell invasion and migration, angiogenesis, and the emergence of cancer-associated fibroblasts. TGF-β is abundantly expressed in cancers and, most often, its abundance associated with poor clinical outcomes. Immunotherapeutic strategies, particularly T cell checkpoint blockade therapies, so far, only produce clinical benefit in a minority of cancer patients. The inhibition of TGF-β activity is a promising approach to increase the efficacy of T cell checkpoint blockade therapies. In this review, we briefly outline the immunoregulatory functions of TGF-β in physiological and malignant contexts. We then deliberate on how the therapeutic targeting of TGF-β may lead to a broadened applicability and success of state-of-the-art immunotherapies.
Early Detection of Prediabetes and T2DM Using Wearable Sensors and Internet-of-Things-Based Monitoring Applications
Authors: Baig Mirza Mansoor , GholamHosseini Hamid , Gutierrez Jairo , Ullah Ehsan , Lindén Maria 
Published: January 2021

Abstract
Background Prediabetes and type 2 diabetes mellitus (T2DM) are one of the major long-term health conditions affecting global healthcare delivery. One of the few effective approaches is to actively manage diabetes via a healthy and active lifestyle.
Objectives This research is focused on early detection of prediabetes and T2DM using wearable technology and Internet-of-Things-based monitoring applications.
Methods We developed an artificial intelligence model based on adaptive neuro-fuzzy inference to detect prediabetes and T2DM via individualized monitoring. The key contributing factors to the proposed model include heart rate, heart rate variability, breathing rate, breathing volume, and activity data (steps, cadence, and calories). The data was collected using an advanced wearable body vest and combined with manual recordings of blood glucose, height, weight, age, and sex. The model analyzed the data alongside a clinical knowledgebase. Fuzzy rules were used to establish baseline values via existing interventions, clinical guidelines, and protocols.
Results The proposed model was tested and validated using Kappa analysis and achieved an overall agreement of 91%.
Conclusion We also present a 2-year follow-up observation from the prediction results of the original model. Moreover, the diabetic profile of a participant using M-health applications and a wearable vest (smart shirt) improved when compared to the traditional/routine practice.
Responding to the pandemic as a family unit: social impacts of COVID-19 on rural migrants in China and their coping strategies
Authors: Tang Shuangshuang , Li Xin 
Published: January 2021

AbstractIn 2020, the COVID-19 pandemic has created tremendous chaos in people’s daily lives around the world. However, the related social impacts vary across social groups. Compared to people with abundant resources, the more disadvantaged tend to suffer greater negative social impacts from disasters. Although it is a crucial topic, there has been limited research on the social impacts of disastrous epidemics on uninfected people in developing countries. To bridge the gap, this study investigates the social impacts of the spread of COVID-19 on rural migrants and their coping strategies through face-to-face interviews with rural migrants in Nanjing, China. The household perspective is highlighted to explore how rural migrants deal with various threats induced by COVID-19 spread. The study finds that rural migrants suffered from serious social impacts due to COVID-19, especially during the associated lockdown period. Despite some similar impacts, influences of COVID-19 varied among rural migrants at different life-cycle stages, due to variations in human capital, family burdens, role in a household, and ability to find part-time work. Receiving little support from governments and employers, rural migrants tended to adopt household strategies to deal with difficulties related to COVID-19. Within a household, they assisted each other and worked as a unit to maximize resources and reduce risks. Traditional family values were highly praised by rural migrant households during the period. Findings also suggest that both central and local governments need to provide practical aid to this group and to improve the social security system for rural migrants.
Shilnikov attractors in three-dimensional orientation-reversing maps
Authors: Karatetskaia Efrosiniia , Shykhmamedov Aikan , Kazakov Alexey 
Published: January 2021

A Shilnikov homoclinic attractor of a three-dimensional diffeomorphism contains a saddle-focus fixed point with a two-dimensional unstable invariant manifold and homoclinic orbits to this saddle-focus. The orientation-reversing property of the diffeomorphism implies a symmetry between two branches of the one-dimensional stable manifold. This symmetry leads to a significant difference between Shilnikov attractors in the orientation-reversing and orientation-preserving cases. We consider the three-dimensional Mirá map x¯=y,y¯=z, and z¯=Bx+Cy+Az−y2 with the negative Jacobian (B&lt;0) as a basic model demonstrating various types of Shilnikov attractors. We show that depending on values of parameters A,B, and C, such attractors can be of three possible types: hyperchaotic (with two positive and one negative Lyapunov exponent), flow-like (with one positive, one very close to zero, and one negative Lyapunov exponent), and strongly dissipative (with one positive and two negative Lyapunov exponents). We study scenarios of the formation of such attractors in one-parameter families.
Resolution of Reissner–Nordström singularities by higher-derivative corrections
Authors: Cano Pablo A , Murcia Ángel 
Published: January 2021

Abstract
We describe a non-minimal higher-derivative extension of Einstein–Maxwell theory in which electrically-charged black holes and point charges have globally regular gravitational and electromagnetic fields. We provide an exact static, spherically symmetric solution of this theory that reduces to the Reissner–Nordström one at weak coupling, but in which the singularity at r = 0 is regularized for arbitrary mass and (non-vanishing) charge. We discuss the properties of these solutions and comment on the physical significance of our results.
High-sensitivity liquid-metal-based contact lens sensor for continuous intraocular pressure monitoring
Authors: An Hongbin , Chen Liangzhou , Liu Xiaojun , Wang Xiangyang , Liu Yunfeng , Wu Zhigang , Zhao Bin , Zhang Hong 
Published: January 2021

Abstract
Intraocular pressure (IOP) is a crucial physiological indicator for the diagnosis and treatment of glaucoma. The current infrequent IOP measurement during an office visit is insufficient to characterize the symptoms. Here, an LC resonator strain sensor in a contact lens, composed of a stretchable inductance coil using liquid metal and a chip capacitor, was developed for real-time IOP monitoring. The lens sensor was operated on the basis of ‘mechanical-electrical’ principle. The rising IOP will increase the curvature radius of the cornea and stretch the inductance coils through the cornea and tear film, leading to a decrease in resonant frequency. The theoretical model of the whole process has been established and explored. The sensor has been scientifically designed and fabricated to be ultra-soft, comfortable, safe without leakage and has a stable signal. The sensor was calibrated on two silicone rubber model eyeballs, respectively, showing linear and stable responses. An experiment on porcine eyes in vitro was conducted. The sensor can track IOP changes and shows much higher sensitivity than the current mainstream lens sensors, which is even an order of magnitude higher than the existing inductive sensor. The high-sensitivity and ultra-flexible liquid-metal-based lens sensor is a promising approach for 24 h continuous IOP monitoring in clinics.
Visible light photocatalytic properties of one-step SnO2-templated grown SnO2/SnS2 heterostructure and SnS2 nanoflakes
Authors: Wang Chiu-Yen , Wu Yu-Kai , Tsai Liang-Feng , Lee Hou-Kuan , Hsu Ya-Chu 
Published: January 2021

Abstract
The nanoflakes of SnS2/SnO2 heterostructure and SnS2 were synthesized by a one-step SnO2-templated chemical vapor deposition method. The metal oxide-assisted growth mechanism of SnS2/SnO2 heterostructure and SnS2 nanoflakes were realized through investigating serial microstructures of products with varied growth time. Furthermore, the photocatalytic activity for MB dyes degradation of varied growth time products was used to explore the effect of product microstructure under the visible light irradiation. The SnO2/SnS2 heterostructure and the oxide vacancies of nanoflakes demonstrated an improved visible light photocatalytic performance for MB degradation, which was around twice of the pure SnS2 nanoflakes and better than P25. The results of different scavengers on the degradation efficiency for MB indicate the·O2
−, and ·OH are the main active species in the photodegradation reaction. The one-step growth mechanism of SnS2/SnO2 could prove a facile process to grow metal oxide-metal sulfide heterostructure.
MOF-derived porous carbon nanofibers wrapping Sn nanoparticles as flexible anodes for lithium/sodium ion batteries
Authors: Zhu Shaoqing , Huang Aoming , Wang Qian , Xu Ye 
Published: January 2021

Abstract
Facile synthesis of flexible electrodes with high reversible capacity plays a key role in meeting the ever-increasing demand for flexible batteries. Herein, we incorporated Sn-based metal-organic framework (Sn-MOF) templates into crosslinked one-dimensional carbon nanofibers (CNFs) using an electrospinning strategy and obtained a hierarchical porous film (Sn@C@CNF) after a carbothermal reduction reaction. Merits of this modification strategy and its mechanism in improving the electrochemical performance of Sn nanoparticles (NPs) were revealed. Electrospun CNFs substrate ensured a highly conductive skeleton and excellent mechanical toughness, making Sn@C@CNF a self-supported binder-free electrode. Serving as a self-sacrificing template, Sn-MOF provided Sn NPs and derived into porous structures on CNFs after pyrolysis. The hierarchical porous structure of the carbon substrate was beneficial to enhancing the Li+/Na+ storage of the active materials, and the carbon wrappings derived from polyacrylonitrile (PAN) nanofibers and the MOF skeleton could jointly accommodate the violent volume variation during cycling, enabling Sn@C@CNF to have excellent cycle stability. The Sn@C@CNF anode exhibited a stable discharge specific capacity of 610.8 mAh g−1 under 200 mA g−1 for 180 cycles in lithium ion batteries (LIBs) and 360.5 mAh g−1 under 100 mA g−1 after 100 cycles in sodium ion batteries (SIBs). As a flexible electrode, Sn@C@CNF demonstrated a stable electromechanical response to repeated ‘bending-releasing’ cycles and excellent electrochemical performance when assembled in a soft-pack half-LIB. This strategy provided promising candidates of active materials and fabrication methods for advanced flexible batteries.
Improved AlScN/GaN heterostructures grown by metal-organic chemical vapor deposition
Authors: Manz Christian , Leone Stefano , Kirste Lutz , Ligl Jana , Frei Kathrin , Fuchs Theodor , Prescher Mario , Waltereit Patrick , Verheijen Marcel A , Graff Andreas , Simon-Najasek Michél , Altmann Frank , Fiederle Michael , Ambacher Oliver 
Published: January 2021

Abstract
AlScN/GaN epitaxial heterostructures have raised much interest in recent years, because of the high potential of such structures for high-frequency and high-power electronic applications. Compared to conventional AlGaN/GaN heterostructures, the high spontaneous and piezoelectric polarization of AlScN can yield to a five-time increase in sheet carrier density of the two-dimensional electron gas formed at the AlScN/GaN heterointerface. Very promising radio-frequency device performance has been shown on samples deposited by molecular beam epitaxy. Recently, AlScN/GaN heterostructures have been demonstrated, which were processed by the more industrial compatible growth method metal-organic chemical vapor deposition (MOCVD). In this work, SiN
x
passivated MOCVD-grown AlScN/GaN heterostructures with improved structural quality have been developed. Analytical transmission electron microscopy, secondary ion mass spectrometry and high-resolution x-ray diffraction analysis indicate the presence of undefined interfaces between the epitaxial layers and an uneven distribution of Al and Sc in the AlScN layer. However, AlScN-based high-electron-mobility transistors (HEMT) have been fabricated and compared with AlN/GaN HEMTs. The device characteristics of the AlScN-based HEMT are promising, showing a transconductance close to 500 mS mm−1 and a drain current above 1700 mA mm−1.
Modelling of a soft multi-chambered climbing robot and experiments
Authors: Xu Fengyu , Quansheng Jiang , Lu Yuxuan , Jiang Guoping 
Published: January 2021

Abstract
Soft robots have wide potential applications prospects in unstructured environments owing to their being able to imitate forms of motion of creatures in climbing and creeping through small spaces. By utilising the high flexibility of soft materials, a pneumatic soft climbing robot was designed. At first, a model for soft climbing robots with a stiffness gradient was designed according to the drive mode of pneumatic networks in soft robots. Afterwards, the visco-mechanical properties of robots at the contact surface were analysed and also the deformation characteristics of cavities were discussed by using the method of minimum potential energy. Subsequently, through simulation and use of the finite element method, the optimal number of cavities in an actuator required by a climbing robot was calculated and also the climbing behaviours of the robot were analysed. Finally, by employing 3D printing and layer-by-layer casting, a prototype soft climbing robot was prepared to perform climbing experiments. The research is expected to provide a new method for monitoring complex unstructured environments.
Electrothermal shape memory behavior and recovery force of four-dimensional printed continuous carbon fiber/polylactic acid composite
Authors: Chen Haijia , Zhang Fenghua , Sun Ya , Sun Baozhong , Gu Bohong , Leng Jinsong , Zhang Wei 
Published: January 2021

Abstract
Four-dimensional (4D) printing technology provides new ideas for the preparation and structural design of multifunctional shape memory composites. Excellent electrothermal shape memory behavior and high shape recovery force are urgently demanded in practical applications. Herein, a continuous carbon fiber reinforced polylactic acid shape memory composite with high strength, high shape recovery force, low-voltage response and excellent electrothermal shape memory behavior was printed using a dual nozzle 3D printer. The effects of specimen thickness, carbon fiber content, and applied voltage on the electrothermal shape memory behavior and shape recovery force were investigated. The reinforcing effect of carbon fiber on 4D printed composite materials was characterized by dynamic mechanical analysis and 3-point bending test. Under electrical thermal stimulation, the shape recovery ratio of most specimens can reach 90%. The shape recovery force of different specimens was obtained by self-designed shape recovery force test system, and the maximum shape recovery force was about 7.38 N. The results show that the introduction of continuous carbon fiber not only significantly enhances the strength of 4D printed composite, but also improves the shape recovery force. The demonstrations of an electrothermal response shape memory deployable claw-device and load-bearing lifting device manifest the potential application in self-actuated intelligent structures.
Asymptotic analysis of the elephant random walk
Authors: Coletti Cristian F , Papageorgiou Ioannis 
Published: January 2021

Abstract
In this work we study asymptotic properties of a long range memory random walk known as elephant random walk. First we prove recurrence and positive recurrence for the elephant random walk. Then, we establish the transience regime of the model. Finally, under the Poisson hypothesis, we study the replica mean field limit for this random walk and we obtain an upper bound for the expected distance of the walker from the origin.
Two-Level Iterative Methods for Solving the Saddle Point Problems
Authors: Il’in V P 
Published: January 2021

Abstract
Iterative processes in the Krylov subspaces for solving large ill conditioned saddle-type SLAEs with sparse matrices arising in finite difference, finite volume, and finite element approximations of multidimensional boundary value problems with complex geometric and functional properties of the initial data, characteristic of many relevant applications are studied. Combined two-level iterative algorithms using efficient Chebyshev acceleration and variational the conjugate directions methods, as well as the Golub-Kahan bi-diagonalization algorithms in the Krylov subspaces are considered. Examples of two-dimensional and three-dimensional filtration problems are used to study the resource consumption and computational performance of the proposed algorithms, as well as their scalable parallization on the multiprocessor systems with distributed and hierarchical shared memory.
A modified algorithm of the latent semantic analysis for text processing in the Russian language
Authors: Ivanov A A , Holtzer S V 
Published: January 2021

Abstract
The paper presents a methodology for analyzing texts in the Russian language. The methodology is based on the Latent Semantic Analysis (LSA) algorithm. A number of disadvantages of the classical method are considered, and modification methods of extracting N-grams from the text are proposed. The modified method allows one to reduce a number of extracted N-grams and an increasing the meaningfulness of the retrieved collection in comparison with a standard method. The reduction of the collection size leads to a reduced dimension of the TF-IDF matrix and accelerated the execution of the SVD method. The advantages of the developed machine learning algorithm are demonstrated on simple sentences. Owing to discussed ideas it becomes possible to effectively parallelize the text processing at the lemmatization step.
The assessment of the atmospheric air quality in Tomsk with the use of a mesoscale photochemical model
Authors: Starchenko A V , Shelmina E A , Kizhner L I , Bart A A 
Published: January 2021

Abstract
The paper presents the results of studying the influence of the development of meteorological situation in clear weather with a weak wind on the level of atmospheric surface air pollution in the city of Tomsk (Russia). Mesoscale meteorological and photochemical models with a new kinetic scheme were applied to the analysis. The main local weather conditions were identified, in which numerical calculations show increased values of the air pollution index. The numerical predictions have confirmed an increase in the ground-level concentration of pollutants in the presence of temperature inversion or isothermy.
A new approach to estimating of the power of nitrogen oxides emissions from the anthropogenic source
Authors: Tikhonov N , Zakharova S , Davydova M 
Published: January 2021

Abstract
The paper presents a new approach to estimating of the power of nitrogen oxides emissions from the anthropogenic source. Authors created the model that describes the dynamics of the formation of a plume from the point anthropogenic source, coordinated in the complexity with the amount of the available data. Based on the proposed model, it is become possible to estimate the emission power by the satellite photographs obtained from the Resource-P series satellite. This estimate is the particular interest in the controlling emissions, which is the complex and non-trivial problem. Also authors determined the distribution of the height-integral amount of nitrogen dioxide over the Hebei Province, China, and compared it with the experimental data. The obtained estimates of the emission power can be used to integrate it into the complex chemical transport models.