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This paper investigates rational solutions of an extended Camassa-Holm-Kadomtsev-Petviashvili equation, which simulates dispersion's role in the development of patterns in a liquid drop, and describes left and right traveling waves like the Boussinesq equation. Through its bilinear form and symbolic computation, we derive some multiple order rational and generalized rational solutions and analyze their dynamic features, such as the connection between rational solution and bilinear equation, scatter behavior, moving path, and exact location of the soliton. The obtained solutions demonstrate two wave forms: multi-lump and multi-wave that consist of three, six and eight lump waves or two, three and four line waves. Moreover, different from the multi-wave solitons, stationary multiple dark waves are presented.

Twinning frequently occurs in nanocrystals during various thermal, chemical, or mechanical processes. However, the nucleation and propagation mechanisms of twinning in nanocrystals remain poorly understood. Through in situ atomic resolution transmission electron microscopy observation at millisecond temporal resolution, we show the twinning in Pb individual nanocrystals via a double-layer swap motion where two adjacent atomic layers shift relative to one another. The swap motion results in twin nucleation, and it also serves as a basic unit of movement for twin propagation. Our calculations reveal that the swap motion is a phonon eigenmode of the face-centered cubic crystal structure of Pb, and it is enhanced by the quantum size effect of nanocrystals.

Fc receptors (FcRs) are key players in antibody-dependent cellular phagocytosis (ADCP) with their specific recognition of the Fc portion of an immunoglobulin. Despite reports of FcγR-mediated phagocytosis in mammals, little is known about the effects of soluble FcγRs on the immune response. In this study, FcγRIα was cloned from the largemouth bass (

The potential for phagocytosis has been proven in teleost B cells, but the research on the regulatory mechanism of phagocytosis remains lacking. In this study, three largemouth bass (Micropterus salmoides) (15 ± 5 g) were injected intraperitoneally with Nocardia seriolae (10

Biorefineries, which utilize lignocellulosic biomass as renewable energy source and sustainable carbon feedstock, are a promising solution to alleviate the excessive dependence on the depleting fossil resources and address climate change and other environmental problems. Owing to the recalcitrance and over-functionalized nature of biomass, the conversion of biomass into desirable products requires a series of complex deconstruction, catalytic conversion, separation and purification processes. In the biorefinery roadmap, 5-hydroxymethylfurfural (HMF) stands out as a bridge connecting biomass raw materials to alternative fuels, chemicals and materials, which can displace petroleum-derived products. This review describes the recent advances in the design and development of catalytic systems for the conversion of biomass and their constituent carbohydrates to HMF via hydrolysis, isomerization and dehydration reactions, and the upgrading of HMF towards polymer monomers, fine chemicals, fuel precursors, fuel additives, liquid fuels, and other platform chemicals via hydrogenation, oxidation, esterification, etherification, amination and aldol condensation reactions, with emphasis on how the catalysts, solvents and reaction conditions determine the reaction pathway and product selectivity. We also attempt to provide a conceptual framework on how to evaluate the actual reaction efficiency, reusability, and economic and technical feasibility of different catalytic systems and highlight the key research challenges to be addressed.

Reaction efficiencies of biorefinery processes are universally low because of the severe side reactions at high substrate loading. Here, we show that the use of Sn-modified Al2O3 catalyst in ionic ...

A memristor1 has been proposed as an artificial synapse for emerging neuromorphic computing applications2,3. To train a neural network in memristor arrays, changes in weight values in the form of device conductance should be distinct and uniform3. An electrochemical metallization (ECM) memory4,5, typically based on silicon (Si), has demonstrated a good analogue switching capability6,7 owing to the high mobility of metal ions in the Si switching medium8. However, the large stochasticity of the ion movement results in switching variability. Here we demonstrate a Si memristor with alloyed conduction channels that shows a stable and controllable device operation, which enables the large-scale implementation of crossbar arrays. The conduction channel is formed by conventional silver (Ag) as a primary mobile metal alloyed with silicidable copper (Cu) that stabilizes switching. In an optimal alloying ratio, Cu effectively regulates the Ag movement, which contributes to a substantial improvement in the spatial/temporal switching uniformity, a stable data retention over a large conductance range and a substantially enhanced programmed symmetry in analogue conductance states. This alloyed memristor allows the fabrication of large-scale crossbar arrays that feature a high device yield and accurate analogue programming capability. Thus, our discovery of an alloyed memristor is a key step paving the way beyond von Neumann computing.

Although conventional homoepitaxy forms high-quality epitaxial layers1-5, the limited set of material systems for commercially available wafers restricts the range of materials that can be grown homoepitaxially. At the same time, conventional heteroepitaxy of lattice-mismatched systems produces dislocations above a critical strain energy to release the accumulated strain energy as the film thickness increases. The formation of dislocations, which severely degrade electronic/photonic device performances6-8, is fundamentally unavoidable in highly lattice-mismatched epitaxy9-11. Here, we introduce a unique mechanism of relaxing misfit strain in heteroepitaxial films that can enable effective lattice engineering. We have observed that heteroepitaxy on graphene-coated substrates allows for spontaneous relaxation of misfit strain owing to the slippery graphene surface while achieving single-crystalline films by reading the atomic potential from the substrate. This spontaneous relaxation technique could transform the monolithic integration of largely lattice-mismatched systems by covering a wide range of the misfit spectrum to enhance and broaden the functionality of semiconductor devices for advanced electronics and photonics.

As thermoplastic materials are widely used in buildings, the fire hazards of thermoplastic materials are increasingly becoming a central issue in fire safety research due to their unique pyrolysis and melting mechanisms. In this paper, the features and common types of thermoplastic materials are introduced first. Then, the combustion behavior of thermoplastic materials is theoretically analyzed based on the empirical formulas and heat balance equations, such as the pyrolysis kinetics, ignition time, melting and dripping, flame, burning rate and mass loss rate, temperature and heat flow, gas products, and influencing factors. The influencing factors basically include the sample properties (width, incline angle, and thickness, etc.), the façade structure (sidewalls, curtain wall, etc.), the ambient conditions (altitude, pressure, and gravity, etc.), and the flame retardant treatment. Similarly, this study also illustrates the vertical and horizontal flame spread behavior of the thermoplastic materials and the influencing factors. The utilized methods include the experimental methods, the analytical methodologies, and the approaches for numerical simulation. Finally, the problems encountered at this stage and worthy of further study in the future are presented.

Understanding nanostructure ripening mechanisms is desirable for gaining insight on the growth and potential applications of nanoscale materials. However, the atomic pathways of nanostructure ripening in solution have rarely been observed directly. Here, we report defect-mediated ripening of Cd-CdCl2 core-shell nanoparticles (CSN) revealed by in-situ atomic resolution imaging with liquid cell transmission electron microscopy. We find that ripening is initiated by dissolution of the nanoparticle with an incomplete CdCl2 shell, and that the areas of the Cd core that are exposed to the solution are etched first. The growth of the other nanoparticles is achieved by generating crack defects in the shell, followed by ion diffusion through the cracks. Subsequent healing of crack defects leads to a highly crystalline CSN. The formation and annihilation of crack defects in the CdCl2 shell, accompanied by disordering and crystallization of the shell structure, mediate the ripening of Cd-CdCl2 CSN in the solution. Published version This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (BES), Materials Sciences and Engineering Division under Contract No. DE-AC02-05-CH11231 within the in-situ TEM program (KC22ZH). Work at the Molecular Foundry of Lawrence Berkeley National Laboratory (LBNL) was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

The phagocytic actives of B cells in fish have been proven in recent years. In this study, five positive hybridomas secreting monoclonal antibodies (MAbs) against largemouth bass IgM were produced. Indirect immunofluorescence assay (IFA) demonstrated that five MAbs could specifically recognize membrane-bound IgM (mIgM) molecule of largemouth bass. Indirect ELISA and Western blotting analysis showed that all the five MAbs had no cross-reactions with the other two teleost IgMs. Flow cytometry analysis (FCM) revealed that the percentages of largemouth bass mIgM

Selective hydrogenation of unsaturated aldehydes to unsaturated alcohols is a valuable but challenging task for synthesizing fine chemicals. We report that single Rh atoms anchored to the edges of 2D MoS2 sheets can efficiently convert crotonaldehyde to crotyl alcohol with 100% selectivity via a steric confinement effect of pocketlike active sites. Characterization results suggest that the synthesized Rh1/MoS2 single-atom catalysts (SACs) possess a unique geometric and electronic configuration, which confines the adsorption mode of the reactant molecule by a steric effect. The DFT calculations suggest that the MoS2 sheets terminate with oxidized Mo edges and the Rh1 stably anchors at the Mo cation vacancy site, which can facilely dissociate H2 to H atoms. The dissociated H atoms spill over to react with the edge O atoms to form OH species and create an HO-Mo-Rh1-Mo-OH configuration, resembling a pocketlike active site, which confines the adsorption mode of the crotonaldehyde due to steric effects. Such specific adsorption configuration yields 100% selectivity. The strategy of constructing pocketlike active centers with single metal atoms and 2D nanosheets opens new approaches to designing highly selective SACs for specific classes of catalytic transformations.

Conversion of biomass-derived glucose to 5-hydroxymethylfurfural (HMF) is an important step for valorizing lignocellulosic biomass. In conventional reaction systems such as aqueous or water-organic solvent biphasic system, degradation of the formed HMF and other intermediates into undesired products is inevitable due to the presence of Bronsted acid, limiting HMF production efficiency. Here, we develop a novel reaction system consisting of heterogeneous catalyst with reduced Bronsted acidity and ionic liquid 1-ethyl-3-methylimidazolium bromide (EMIMBr) to achieve the efficient conversion of high-concentration glucose to HMF. A series of Al-containing materials was synthesized and characterized by N2 adsorption-desorption, XRD, XPS, FIIR, Py-IR and CO2 TPD, among which the Al2O3-b-0.05 prepared by simple alkaline treatment exhibited high Lewis acidity and low Bronsted acidity. The Al2O3-b-0.05 in the medium of EMIMBr leaded to the highest HMF yield of 49.7% from high-concentration glucose (up to 10 wt%), as is more efficient than the heterogeneous EMIMCl/Al2O3-b-0.05 and homogeneous EMIMBr/AlCl3 system. This work provides a paradigm of improving HMF production efficiency via the combined use of heterogeneous Lewis acid catalyst and ionic liquid.

The correlation between lattice oxygen (O) binding energy and O oxidation activity imposes a fundamental limit in developing oxide catalysts, simultaneously meeting the stringent thermal stability ...

Atomic layer deposition is a chemical deposition technology that provides ultimate control over the conformality of films and their thickness, even down to Angstrom-scale precision. Based on the marked superficial character and gas phase process of the technique, metal sources and their ligands shall ideally be highly volatile. However, in numerous cases those ligands corrode the substrate or compete for adsorption sites, well-known as side reactions of these processes. Therefore, the ability to control such side reactions might be of great interest, since it could achieve synchronous coating and alteration of a substrate in one process, saving time and energy otherwise needed for a post-treatment of the sample. Consequently, advances in this way must require understanding and control of the chemical processes that occur during the coating. In this work, we show how choosing an appropriate ligand of the metal source can unveil a novel approach to concertedly coat and reduce γ-Fe2O3 nanoparticles to form a final product composed of Fe3O4/TiO2 core/shell nanoparticles. To this aim, we envisage that appropriate design of precursors and selection of substrates will pave the way for numerous new compositions, while the ALD process itself allows for easy upscaling to large amounts of coated and reduced particles for industrial use.

Photocatalysis has exhibited huge potential in many reactions, but the design of metal-free photocatalytic material for selective upgrading of biomass is rarely achieved. Here, we report that the metal-free photocatalyst consisted of nitrogen-deficient carbon nitride (BNCN) and chlorin e6 (Ce6) can efficiently and selectively oxidize glucose into gluconic acid and glucaric acid. Introducing nitrogen defects could significantly enhance the optical absorption and modulate the band structure. In addition, the combination of Ce6 with BNCN further improve the optical absorption property and promote effective separation of photon-generated carriers. As expected, the resultant Ce6@BNCN catalyst gave a total selectivity of gluconic acid, glucaric acid and arabinose as high as 70.9% at glucose conversion up to 62.3%, as is superior to previously reported photocatalytic systems. The mechanism for the enhancement of catalytic performance and the reaction pathway were revealed by experimental studies combined with DFT calculations.

Deployable solar arrays play an important role in the realization of various spacecraft missions. Taking the flexible spacecraft as an application background, the natural characteristics of...

It has recently been shown that quantum-confined states can appear in epitaxially grown van der Waals material heterobilayers without a rotational misalignment (θ = 0°), associated with flat bands in the Brillouin zone of the moiré pattern formed due to the lattice mismatch of the two layers. Peaks in the local density of states and confinement in a MoS

Recently, many neural retrieval models have been proposed and shown competitive results. In particular, interaction-based models have shown superior performance to traditional models in a number of studies. However, the interactions used as the basic matching signals are between single terms or their embeddings. In reality, a term can often match a phrase or even longer segment of text. This paper proposes a Cross-Level Matching Model which enhances the basic matching signals by allowing terms to match hidden representation states within a sentence. A gating mechanism aggregates the learned matching patterns of different matching channels and outputs a global matching score. Our model provides a simple and effective way for word-phrase matching.

International audience; The transparency of two-dimensional (2D) materials to intermolecular interactions of crystalline materials has been an unresolved topic. Here we report that remote atomic interaction through 2D materials is governed by the binding nature, that is, the polarity of atomic bonds, both in the underlying substrates and in 2D material interlayers. Although the potential field from covalent-bonded materials is screened by a monolayer of graphene, that from ionic-bonded materials is strong enough to penetrate through a few layers of graphene. Such field penetration is substantially attenuated by 2D hexagonal boron nitride, which itself has polarization in its atomic bonds. Based on the control of transparency, modulated by the nature of materials as well as interlayer thickness, various types of single-crystalline materials across the periodic table can be epitaxially grown on 2D material-coated substrates. The epitaxial films can subsequently be released as free-standing membranes, which provides unique opportunities for the heterointegration of arbitrary single-crystalline thin films in functional applications.

Advances in ex situ and in situ (operando) characteristic techniques have unraveled unprecedented atomic details in the electrochemical reaction of Li-ion batteries. To bridge the gap between emerging evidences and practical material development, an elaborate understanding on the electrochemical properties of cathode materials on the atomic scale is urgently needed. In this work, we perform comprehensive first-principle calculations within the density functional theory + U framework on the surface stability, morphology, and elastic anisotropy of Ni-rich LiNi1-2yCoyMnyO2 (NCM) (y ≤ 0.1) cathode materials, which are strongly related to the emerging evidence in the degradation of Li-ion batteries. On the basis of the surface stability results, the equilibrium particle morphology is obtained, which is mainly determined by the oxygen chemical potential. Ni-rich NCM particles are terminated mostly by the (012) and (001) surfaces for oxygen-poor conditions, whereas the termination corresponds to the (104) and (001) surfaces for oxygen-rich conditions. Besides, Ni surface segregation predominantly occurs on the (100), (110), and (104) nonpolar surfaces, showing a tendency to form a rocksalt NiO domain on the surface because of severe Li-Ni exchange. The observed elastic anisotropy reveals that an uneven deformation is more likely to be formed in the particles synthesized under poor-oxygen conditions, leading to crack generation and propagation. Our findings provide a deep understanding of the surface properties and degradation of Ni-rich NCM particles, thereby proposing possible solution mechanisms to the factors affecting degradation, such as synthesis conditions, coating, or novel nanostructures.

Two-dimensional materials have shown great promise for implementation in next-generation devices. However, controlling the film thickness during epitaxial growth remains elusive and must be fully understood before wide scale industrial application. Currently, uncontrolled multilayer growth is frequently observed, and not only does this growth mode contradict theoretical expectations, but it also breaks the inversion symmetry of the bulk crystal. In this work, a multiscale theoretical investigation aided by experimental evidence is carried out to identify the mechanism of such an unconventional, yet widely observed multilayer growth in the epitaxy of layered materials. This work reveals the subtle mechanistic similarities between multilayer concentric growth and spiral growth. Using the combination of experimental demonstration and simulations, this work presents an extended analysis of the driving forces behind this non-ideal growth mode, and the conditions that promote the formation of these defects. Our study shows that multilayer growth can be a result of both chalcogen deficiency and chalcogen excess: the former causes metal clustering as nucleation defects, and the latter generates in-domain step edges facilitating multilayer growth. Based on this fundamental understanding, our findings provide guidelines for the narrow window of growth conditions which enables large-area, layer-by-layer growth.

In this paper, to identify the roof unconfined compressive strength (UCS) in the process of coal mine roadway support in real-time and optimize the real-time drilling speed while drilling, this paper proposes and establishes a drilling test method for assessing the uniaxial compressive strength (UCS) of a roof. This method can be used to optimize the speed of drilling. Moreover, a mathematical model of the power output is developed for a roof-strata identification system with a drilling test system. The results were as follows: (1) the system was able to identify the uniaxial compressive strength of roof rock, (2) the pressure of the drill leg of the pneumatic bolt did not match the output power of the pneumatic motor, the pneumatic motor could not reach the maximum power point, and the insufficient thrust of the pneumatic leg led to failure of the maximum output power of the pneumatic motor, (3) to increase the output power of the air motor and thus improve the drilling speed, we applied a booster valve for the system. The experimental results show that the power of the air motor has a linear relationship with drilling speed. In this way, the speed of the drill can be increased by increasing the motor power.

To achieve efficient degradation of pharmaceutical and personal care products (PPCPs), dual reaction centers ZnO@FePc photo-Fenton catalysts with high-speed electron transmission channel were designed through surface hydroxyl-induced assembly. In ZnO@FePc catalytic system, the photocatalysis center of ZnO and Fenton catalytic center of FePc were formed simultaneously. Concept and process for the control of hydroxyl groups to construct a dual reaction center ZnO@FePc photo-Fenton catalyst were verified ingeniously based on the density functional theory (DFT) analysis and experimental results. A series of catalysts, including ZIF-8 (400 ℃-N2), FePc (400 ℃-N2), ZIF-8 (400 ℃)-FePc (400 ℃) and ZnO@FePc were prepared and characterized by XRD, FTIR, TEM, BET, XPS, PL and DRS, respectively. The ZnO@FePc catalyst showed superior performance for the photo-Fenton degradation of ibuprofen, affording degradation rate larger than 90 % within just 10 min under simulateed sunlight. The excellent performance of ZnO@FePc catalyst is mainly attributed to the synergistic effect between dual reaction centers of ZnO@FePc. This work provides a novel method to construct dual reaction centers ZnO@FePc catalyst with efficient photo-generated electrons transmission link and to strengthen the synergistic effect of dual reaction centers.

Conventional mechanical or chemical exfoliation approach of 2D material synthesis is largely dependent on the inherent structure of the parent material, i.e., whether it is a layered structure or a 3D bulk structure with embedded 2D substructures. A recent experiment demonstrated that unprecedented atomically thin metal oxides without bulk layered structures can be synthesized by using liquid metals. Supported by an experimental realization of atomically thin W layers through the metal atomic layer deposition method, we propose a new type of transition metal (TM)-based 2D materials that can be stabilized at the oxide interfaces with oxide substrates and overlayers. Based on the ab initio density functional theory calculations, we show that most of the TM elements can form unprecedented atomically thin 2D materials by the surface oxygen passivation, which is available from the oxide substrate and the overlayer. The stabilized 2D TM layers show diverse electronic and magnetic properties. Our results suggest a novel way to extend 2D materials study and a possible application of those 2D TM layers embedded in oxides.

First-principles calculations have been carried out to investigate the adsorption of a hydrogen adatom on 24 metal doped α-Zr (0 0 0 1) surfaces in both a vacuum and an implicit solvation environment. The dopant are the elements in the 4th and 5th periods in the periodic table. Doping elements at the tail of the 4th and 5th periods can significantly reduce the hydrogen pickup in a vacuum environment. A weighted d-band center theory is used to analyze the doping effect. On the other hand, the hydrogen adsorption energies in water are relatively lower for all doped slabs and the surface adsorption of hydrogen adatom is stronger than that in a vacuum environment, especially, for the slabs with doping elements at the tail of the 4th and 5th periods. In the solvation environment, electronegativity difference affects the adsorption. Doping elements Ag, Ga, Ge, Sn, and Sb can reduce the hydrogen pickup in vacuum, while Ag and Cu can reduce the hydrogen pickup of the zirconium alloys in solvent environment.

In this work, we perform a comprehensive study of five phenomena of LiNi1-2xCoxMnxO2 (NCM) (x = 0–1/3) cathodes at the end of charge (phase reaction, crack propagation, Li-Ni exchange, phase transition, and oxygen evolution), using first-principle calculations within the DFT + U framework. Based on our results, we have located the obstacles toward unity efficiency and revealed that the degradation strongly depends on the Ni concentration and the depth of charge. The threshold capacities for degradation of LiyNi1-2xCoxMnxO2 are 130–140 mA·hg−1 (y

Transition metal (TM) modification is a common strategy for converting an earth-abundant mineral into a cost-effective catalyst for industrial applications. Among a variety of minerals, Al2SiO5, which has three phases, andalusite, sillimanite and kyanite, is emerging as a promising candidate for new catalyst development. In this paper, we use Mn to demonstrate the rationale of 3d TM doping at the Al sites in each of these three phases through first-principles calculations and the cluster expansion method. The results of cluster expansion show that Mn has a strong site preference for the six-coordinated Al octahedral chains in the andalusite and sillimanite phases, while distributing randomly in the kyanite phase. Moreover, Mn can only replace Al in sillimanite and kyanite in low concentrations; however, higher concentrations of Mn can replace Al in andalusite. We found that the concentration sensitivity is due to the Jahn-Teller distortion and 3d orbital splitting. This finding can also explain the low doping concentrations of other 3d TMs (Fe, Cr and V) in Al2SiO5 compounds. Based on the calculated Helmholtz free energy, we constructed a (MnxAl1-x)AlSiO5 temperature-composite phase diagram, which explains the physical mechanisms behind the results for 3d transition metal doping and phase transitions in Al2SiO5. This work could shed light on the related physics, chemistry, and geoscience of (MnxAl1-x)AlSiO5, and more importantly, a design rationale for the engineering of cheap catalysts.

Atomic substitution and doping are two of the most adopted strategies to improve the electrochemical performance of layered cathode materials for Li-ion batteries (LIBs). In this work, we report a comprehensive study on the effects of seven dopants (Al, Ga, Mg, Si, Ti, V, and Zr) on the well-known drawbacks of Ni-rich LiNi1−2yCoyMnyO2 (NCM) (y ≤ 0.1), one of the most promising next-generation cathode materials for LIBs, including phase instability, Li–Ni exchange, Ni segregation, lattice distortion, and oxygen evolution. Our results show that there is not a single dopant that can solve all the problems at the same time and, moreover, while they often improve certain properties, they may have no effect or even worsen others. By comparing different doping sites, we found a strong site preference due to the tradeoff between Mn and Co concentrations. This site preference indicates that a multicomponent-doping strategy should be adopted at both Mn and Co sites. Finally, a rationale for the optimization of the overall electrochemical performance of Ni-rich NCM is proposed, which will ultimately provide practical guidance (Ti or Zr at the Co site and Al at the Mn site) for the design of new Ni-rich layered cathode materials for LIBs.

The mineralization of organic pollutants under visible light is challenging, limiting the practical application of photocatalytic technology in wastewater treatment. To achieve the efficient mineralization of Acid red 3R (AR3R), a series of honeycombed catalysts (TiO

Selective hydrogenation of unsaturated aldehydes to unsaturated alcohols is a valuable but challenging task for synthesizing fine chemicals. We report that single Rh atoms anchored to the edges of 2D MoS

A memristor

Recent deep learning models for information retrieval typically aim to learn features either about the contents of the document and the query, or about the interactions between them. However, the existing literature shows that document ranking depends simultaneously on many factors, including both content and interaction features. The integration of both types of neural features has not been extensively studied. In addition, many studies have also shown that the deep neural features cannot replace completely the traditional features, but are complementary. It is thus reasonable to combine deep neural features with traditional features. In this paper, we propose an integrated end-to-end learning framework based on learning-to-rank (L2R) to learn both neural features and the L2R ranking function simultaneously. The framework also has the flexibility to integrate arbitrary traditional features. Our experiments on public datasets confirm that such an integrated learning strategy is better than separate learning of features and ranking function, and integrating traditional features can further improve the results.

The wireless charging technology (WPT) is a hot research topic at present. Because of its plug-in-free feature, it is very suitable for patrol robots. In order to reduce the influence of wireless charging coupling mechanism on electromagnetic environment in non-working area, a shielding device was designed and its finite element model (FEM) was established. The feasibility of the method was verified by finite element calculation. The simulation results show that the horizontal active shielding coil can significantly reduce the vertical electromagnetic leakage and eddy current loss of the magnetic coupling mechanism, and the vertical active shielding coil can effectively reduce the horizontal electromagnetic leakage, thereby reducing the radiation loss. It is proved that the active shielding coil can enhance the uniformity of space magnetic field and reduce the electromagnetic interference from the wireless charging system of inspection robot.

Generalized Frequency Division Multiplex (GFDM) is a new multiple subcarrier modulation technology. The problem of inter-carrier interference (ICI) caused by non-orthogonality using GFDM modulation is analyzed in this paper. For fading channel, a new double-band self-interference cancellation algorithm based on channel status information is proposed. Simulation results show that the bit error rate (BER) level of the GFDM system can be controlled to a lower level by the proposed method.

To face the challenge of spectral efficiency for the conventional binary chirp-BOK modulation, an M-ary chirp modulation (MCM) is proposed. Different from the traditional quadrature amplitude modulation technology, M-ary chirp modulation scheme with a constant envelope uses up-chirp and down-chirp as orthogonal components. The expression for its symbol error rate (SER) under AWGN channel is given. MCM has much better performance than MPSK under the multipath fading channels which are selected from COST207 standard.

Due to the relative movement between the transmitter and receiver in wireless communication systems, Doppler shift and time delay are introduced results in the probability of symbol synchronization decreases. Therefore, fast and steady synchronization method is pretty important. In this paper, a new symbol synchronization scheme based on chirp signals has been proposed. The proposed coarse synchronization sequence chosen five chirp signals with same chirp rates which time and bandwidth (TB) product is higher, while the fine synchronization sequence is composed of chirp signals with different chirp rates which TB product is small. The performance of the proposed scheme is evaluated via simulations. The simulation results show that the performance of proposed scheme is superior, and achieves a clearly performance gain with a high estimation accuracy both in timing and frequency offset.

The correlation between lattice oxygen (O) binding energy and O oxidation activity imposes a fundamental limit in developing oxide catalysts, simultaneously meeting the stringent thermal stability and catalytic activity standards for complete oxidation reactions under harsh conditions. Typically, strong O binding indicates a stable surface structure, but low O oxidation activity, and

Resonant wireless charging technology can overcome many shortcomings of traditional charging methods and is favored by universities and research institutions in the world. However, the inevitable leakage flux during transmission may cause electromagnetic interference problems. First of all, this paper designs a set of coils for resonant wireless charging system with the background of wireless charging of slow-moving inspection robots. Secondly, the magnetic field distribution around the coil is analyzed, and some indicators are established to evaluate its shielding performance. Some shielding designs are simulated where the magnetic induction intensity exceeds the standard. Finally, the shielding method is validated by experiments, and some guiding suggestions are put forward for the safe development of wireless charging system.

In this Letter, we use first-principles simulations to demonstrate the absence of Fermi-level pinning when graphene is in contact with transition metal dichalcogenides (TMDs). We find that formation of either an ohmic or Schottky contact is possible. Then we show that, due to the shallow density of states around its Fermi level, the work function of graphene can be tuned by ion adsorption. Finally we combine work function tuning of graphene and an ideal contact between graphene and TMDs to propose an ionic barristor design that can tune the work function of graphene with a much wider margin than current barristor designs, achieving a dynamic switching among p-type ohmic contact, Schottky contact, and n-type ohmic contact in one device.