- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2019
- 2018
- electromagnetic pulse
- cell proliferation
- cell membrane permeability
- cell response to electromagnetic stress
- apoptosis
- cancer therapy
- necrosis
- periodic structures
- electromagnetic screening
- filtering
- Optoelectronic Information Science and Engineering
- Intelligent Medical Engineering
- Southern University of Science and Technology
- Politehnica University of Timi?oara
- Wroclaw University of Technology
- Centro de laseres pulsados
- Szchenyi Istvn University
- ELI-ALPS, ELI-HU Non-Profit Ltd.
- V.N. Karazin Kharkiv National University
- Politecnico di Torino
- Centro de laseres pulsados and University of Salamanca
-
Electronic and Magnetic Properties of Transition-Metal-Doped WS? Monolayer; First-Principles Investigations
摘要： The electronic structures and magnetic properties of the transition-metal (TM)-doped WS2 monolayers are investigated by using the first-principles calculations within the density functional theory. The W atoms of the pristine WS2 monolayer are partially replaced by the 3d TMs of Mn, Fe, Co, and Cu with the impurity concentration of about 4%. For the uniformly distributed doping, the ferromagnetic phases are found to be stabilized with the total spin magnetic moments of 1.00, 2.00, 3.00, and 1.00 μB for the Mn-, Fe-, Co-, and Cu-doping, respectively, where not only the spin moments of the TM dopants but also the induced spin moments of the W and S atoms contribute significantly depending on the dopant type as well as on the relaxation. All systems are found to be half-metallic with the spin gap of 0.10–0.53 eV. Among them, the biggest spin gap is found for the doping of Co which is the ingredient of the well-known half-metallic Heusler alloys. When the TM dopants were brought closer keeping the same impurity concentration, the preference of the substitutional doping site and the magnetic phase is changed sensitively depending on the type of doping and the interatomic distance between the TM dopants.
关键词： spin density,transition-metal (TM) dopant,Magnetic state,WS2 monolayer.
更新于2025-09-23 15:22:29
-
Weighted Manifold Alignment using Wave Kernel Signatures for Aligning Medical image Datasets
摘要： Manifold alignment (MA) is a technique to map many high-dimensional datasets to one shared low-dimensional space. Here we develop a pipeline for using MA to reconstruct high-resolution medical images. We present two key contributions. Firstly, we develop a novel MA scheme in which each high-dimensional dataset can be differently weighted preventing noisier or less informative data from corrupting the aligned embedding. We find that this generalisation improves performance in our experiments in both supervised and unsupervised MA problems. Secondly, we use the wave kernel signature as a graph descriptor for the unsupervised MA case finding that it significantly outperforms the current state-of-the-art methods and provides higher quality reconstructed magnetic resonance volumes than existing methods.
关键词： Slice stacking,Wave kernel signature,Magnetic resonance imaging,Manifold alignment,Graph descriptor
更新于2025-09-23 15:22:29
-
Can one introduce long range ferromagnetism by doping transition metal in wide band gap semiconducting ZnO?
摘要： In this report, we present a systematic study of magnetic behavior of transition metal (TM = Fe or Cu) doped ZnO and co-doped (Cu, Fe) ZnO nanoparticles. All the samples show antiferromagnetic (AFM) like inverse susceptibility at low temperatures. In all the samples AFM Curie-Weiss temperature TAF M increases with increase in TM ion concentration indicating enhanced antiferromagnetic correlation upon TM doping. We observe a crossover from antiferromagnetic correlation state to ferromagnetic correlation around temperature (T) 100 - 150K. We shall try to explain all the experimental observations by invoking the role of oxygen vacancies, valency of transition metal ions, formation and interaction between bound magnetic polaron (BMP) and their melting in ZnO matrix. Even though we observe ferromagnetic correlation around room temperature in all these samples from the inverse magnetic susceptibility data, but no true long range ferromagnetic transition was observed in magnetization down to lowest measured temperature of 5K. Our study indicates the di?culties in achieving long range ferromagnetism arising due to the formation of BMPs upon lowering the temperature where these BMPs get antiferromagnetically correlated due to superexchange interaction occurring in transition metal doped wide band gap semiconducting ZnO matrix.
关键词： Dilute magnetic semiconductor,Bound magnetic polaron,Antiferromagnetism,Transition metal doping,ZnO,Ferromagnetism
更新于2025-09-23 15:21:21
-
Effect of Terraces at the Interface on the Structural and Physical Properties of La <sub/>0.8</sub> Sr <sub/>0.2</sub> MnO <sub/>3</sub> Thin Films
摘要： Employing atomic force microscopy, transmission electron microscopy and the second harmonic generation technique, we carefully explore the structural properties of 6-unit-cell-thick La0.8Sr0.2MnO3 films grown on SrTiO3 with atomically flat TiO2-terminated terraces on the surface. The results clearly demonstrate that the terraces on the surface of TiO2-terminated SrTiO3 can improve the layer-by-layer epitaxial growth of the manganite films, which results in uniform film coverage at the beginning of growth and thus reduces the substrate-induced disorder at or near the interface. Comparing the magnetic and transport properties of La0.8Sr0.2MnO3 films with the thicknesses varying from 6 unit cells to 80 unit cells grown respectively on as-received SrTiO3 and TiO2-terminated SrTiO3, it is found that these atomically flat terraces on the surface of TiO2-terminated SrTiO3 can greatly enhance the Curie temperature and conductivities of the ultrathin La0.8Sr0.2MnO3 films with thickness less than 50 unit cells, while no obvious difference is detected in the magnetic and transport properties of the 80 unit-cell thick films.
关键词： La0.8Sr0.2MnO3,transport properties,SrTiO3,terraces,magnetic properties,structural properties
更新于2025-09-23 15:21:21
-
Ultrathin Flexible Carbon Fiber Reinforced Hierarchical Metastructure for Broadband Microwave Absorption with Nano Lossy Composite and Multi-scale Optimization
摘要： The implementation of thin structure for broadband microwave absorption is challenging due to requirement of impedance match across several frequency bands and poor mechanical properties. Herein, we demonstrate a carbon fiber (CF) reinforced flexible thin hierarchical metastructure (HM) composed of lossy materials including carbonyl iron (CI), multiwall carbon nanotube (MWCNT) and silicone rubber (SR) with thickness of 5mm and optimal concentration selected from twelve formulae. Optimization for the periodical unit size is applied and impacts of structural sizes on absorption performance is also investigated. An effective process combining the vacuum bag method and the hand lay-up technique is used to fabricate the HM. Experimental reflectivity of the absorber achieves broadband absorption below -10dB in 2-4GHz and 8-40GHz. Full band in 2-40GHz is covered below -8dB. Yielding stress of the HM is increased to 24MPa with attachment of CF while the fracture strain of the composite reaches 550%. The soft HM is suitable to adhere to curved surface of objects needed to be protected from microwave radiation detection and electromagnetic interference. Enhanced mechanical properties make it possible for further practical applications under harsh service environment such as ocean and machines with constant vibration.
关键词： broadband microwave absorption,hierarchical metastructure,dielectric-magnetic lossy material,flexible,mechanical properties
更新于2025-09-23 15:21:21
-
An Enzyme-Free MicroRNA Assay Based-on Fluorescence Counting of Click Chemical Ligation-Illuminated Magnetic Nanoparticles with Total Internal Reflection Fluorescence Microscopy
摘要： MicroRNAs (miRNAs) have been considered as promising cancer biomarkers. However, the simple but sensitive detection of low levels of miRNAs in biological samples still remains challenging. Herein, we wish to report an entirely enzyme-free, simple and highly sensitive miRNA assay based on the counting of cycling click chemical ligation (3CL)-illuminated fluorescent magnetic nanoparticles (MNPs) with a total internal reflection fluorescence microscopy (TIRFM). In this strategy, each miRNA molecule can trigger many cycles of click chemical ligation reactions to produce plentiful ligated oligonucleotides (ODNs) with both 5’-biotin and 3’-fluorophore, resulting in efficient signal amplification. It is worth noting that only the ligated ODNs can bring fluorophores onto streptavidin-functionalized MNPs (STV-MNPs). Notably, merely 10 fluorescent molecules on each 50 nm MNP can make it bright enough to be clearly visualized by the TIRFM, which can significantly improve the detection sensitivity for miRNA. Through fluorescence counting of individual MNPs and integrating their fluorescence intensities, the amount of target miRNA can be quantitatively determined. This miRNA assay can be accomplished in a mix-and-read manner just by simply mixing the enzyme-free 3CL reaction system with the MNPs before TIRFM imaging, which avoids tedious immobilization, washing and purification steps. Despite the extremely simple operation, this strategy exhibits high sensitivity with a quite low detection limit of 50 fM target miRNA as well as high specificity to well discriminate miRNA sequences with a single-base variation. Furthermore, the applicability of this method in real biological samples is also verified through the accurate detection of miRNA target in cancer cells.
关键词： click chemistry,microRNA,TIRFM,magnetic nanoparticle,fluorescence counting
更新于2025-09-23 15:21:21
-
Thin Films
摘要： We demonstrate how to extract the material-dependent spin-torque efficiency (ξ) and asymmetry (λ) from the field-current nucleation boundaries of magnetic droplet solitons in orthogonal nano-contact spin-torque oscillators with Cox(Ni80Fe20)1?x, (x = 0 ? 1), fixed layers. As the perpendicular component of the fixed-layer magnetization plays a central role in governing droplet nucleation, the nucleation boundaries exhibit monotonic shifts towards higher perpendicular magnetic fields when the fixed-layer magnetization μ0Ms,p is tuned from 1.04 to 1.7 T. We then extract ξ and λ from fits to the nucleation boundaries and find that while ξ does not vary with composition, λ increases from 1.5 to 3 with increasing Co content. The analysis of droplet nucleation boundaries is hence a useful tool for the systematic study of both ξ and λ as functions of material composition.
关键词： Cox(Ni80Fe20)1?x,magnetic droplet solitons,spin-torque asymmetry,spin-torque efficiency,nano-contact spin-torque oscillators
更新于2025-09-23 15:21:21
-
Compact IR synchrotron beamline design
摘要： Third-generation storage rings are massively evolving due to the very compact nature of the multi-bend achromat (MBA) lattice which allows amazing decreases of the horizontal electron beam emittance, but leaves very little place for infrared (IR) extraction mirrors to be placed, thus prohibiting traditional IR beamlines. In order to circumvent this apparent restriction, an optimized optical layout directly integrated inside a SOLEIL synchrotron dipole chamber that delivers intense and almost aberration-free beams in the near- to mid-IR domain (1–30 mm) is proposed and analyzed, and which can be integrated into space-restricted MBA rings. Since the optics and chamber are interdependent, the feasibility of this approach depends on a large part on the technical ability to assemble mechanically the optics inside the dipole chamber and control their resulting stability and thermo-mechanical deformation. Acquiring this expertise should allow dipole chambers to provide almost aberration-free IR synchrotron sources on current and ‘ultimate’ MBA storage rings.
关键词： integrating magnetic and photonic synchrotron beamline components,multi-bend achromat storage ring,infrared synchrotron beamline,bending-magnet source,optical aberrations
更新于2025-09-23 15:21:21
-
Perspective: Prospects of non-invasive sensing of the human brain with diffuse optical imaging
摘要： Since the initial demonstration of near-infrared spectroscopy (NIRS) for noninvasive measurements of brain perfusion and metabolism in the 1970s, and its application to functional brain studies (fNIRS) in the 1990s, the field of noninvasive optical studies of the brain has been continuously growing. Technological developments, data analysis advances, and novel areas of application keep advancing the field. In this article, we provide a view of the state of the field of cerebral NIRS, starting with a brief historical introduction and a description of the information content of the NIRS signal. We argue that NIRS and fNIRS studies should always report data of both oxy- and deoxyhemoglobin concentrations in brain tissue, as they complement each other to provide more complete functional and physiological information, and may help identify different types of confounds. One significant challenge is the assessment of absolute tissue properties, be them optical or physiological, so that relative measurements account for the vast majority of NIRS and fNIRS applications. However, even relative measurements of hemodynamics or metabolic changes face the major problem of a potential contamination from extracerebral tissue layers. Accounting for extracerebral contributions to fNIRS signals is one of the most critical barriers in the field. We present some of the approaches that were proposed to tackle this challenge in the study of cerebral hemodynamics and functional connectivity. Finally, we critically compare fNIRS and functional magnetic resonance imaging by relating their measurements in terms of signal and noise, and by commenting on their complementarity.
关键词： hemodynamics,functional connectivity,functional magnetic resonance imaging,human brain,near-infrared spectroscopy,diffuse optical imaging,non-invasive sensing,functional near-infrared spectroscopy
更新于2025-09-23 15:21:21
-
Coupling Effect of Magnetic Fields on Piezotronic and Piezo-Phototronic Properties of ZnO and ZnO/Co <sub/>3</sub> O <sub/>4</sub> Core/Shell Nanowire Arrays
摘要： Piezoelectric-related multi-property coupling effects have recently attracted much attention for developing next generation multi-functional devices. In this paper, the multi-property coupling effects among magnetic field, piezoelectricity and photoexcitation were investigated in ZnO nanowire arrays. The response of the current flowing through the array to the applied magnetic field was decreasing with increasing magnetic field strength. However, due to piezo-magnetotronic effect, the magnetically induced current was magnified by one order of magnitude by applying an external stress. In contrast, under UV light illumination, the magnetically induced current response increased with an increment of magnetic field strength, as the magnetic field is favorable to the separation of photo-induced electron-hole pairs. The magnetically-induced current response was enhanced by at least two orders of magnitude due to the piezo-photo-magnetotronic effect. Furthermore, ZnO/Co3O4 core/shell heterojunction nanowire arrays was employed to improve the current responses up to 9 times and 3 times, under piezo-magnetotronic and piezo-photo-magnetotronic engagements, respectively, attributed to the improved charge carrier separation and transportation at the core/shell interface. This phenomenon projects a potential for multi-functional piezo-magnetotronic and piezo-photo-magnetotronic device development.
关键词： Piezotronic effect,Magnetic Field,Piezo-Photo-Magnetotronic effect,Piezo-Magnetotronic effect
更新于2025-09-23 15:21:21