The topological magnetoelectric effect (TME) is a hallmark response of the topological field theory,which provides a paradigm shift in the study of emergent topological ***,its direct observation is yet to be realiz...
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The topological magnetoelectric effect (TME) is a hallmark response of the topological field theory,which provides a paradigm shift in the study of emergent topological ***,its direct observation is yet to be realized due to the demanding magnetic configuration required to gap all surface ***,we theoretically propose that axion insulators with a simple ferromagnetic configuration,such as the MnBi2Te4/(Bi2Te3)nfamily,provide an ideal playground to realize the *** the designed triangular prism geometry,all the surface states are magnetically *** a vertical electric field,the surface Hall currents give rise to a nearly half-quantized orbital moment,accompanied by a gapless chiral hinge mode circulating in ***,the orbital magnetization from the two topological origins can be easily distinguished by reversing the electric *** work paves the way for direct observation of the TME in realistic axion-insulator materials.
The critical challenges of the energy crisis and environmental degradation promote innovative approaches for energy ***-based photocatalytic technology,which transforms solar energy into chemical energy,emerges as a p...
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The critical challenges of the energy crisis and environmental degradation promote innovative approaches for energy ***-based photocatalytic technology,which transforms solar energy into chemical energy,emerges as a promising ***,the practical application of this technology faces several challenges,such as the rapid recombination of photogenerated electrons and holes,significantly limiting photocatalytic *** this review,we provide a detailed discussion,an insightful perspective,and a critical evaluation of recent advances,challenges,and opportunities in the field of photocatalysis using polar *** present a comprehensive examination of the photocatalytic mechanisms,activity,and diverse applications of photocatalysts based on polar *** also briefly discuss the engineering design of polar photocatalysis in experiments and its scalability in the *** review outlines future trends and potential breakthroughs in the photocatalytic field using polar materials,projecting their transformative impact on environmental chemistry and energy engineering.
High performance dielectric resonator(DR) bandpass filters(BPFs) are critical components in modern RF/microwave front-end systems due to their many distinctive advantages like low loss, small size, light weight, and t...
High performance dielectric resonator(DR) bandpass filters(BPFs) are critical components in modern RF/microwave front-end systems due to their many distinctive advantages like low loss, small size, light weight, and temperature-stable properties. In recent years, the rapid development of various wireless communication techniques is demanding much more critical specifications for microwave BPFs with better performance but further reduced loss, size, and *** a prospective approach to meet these stringent requirements, BPFs using triple-mode DRs are attracting much attention from both academia and industry [1–5].
Chevrel phase compounds have attracted increasing attention as electrochemical energy storage materials and electro-catalysts. Benefiting from their unique crystal structure, Chevrel phase compounds can not only funct...
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Chevrel phase compounds have attracted increasing attention as electrochemical energy storage materials and electro-catalysts. Benefiting from their unique crystal structure, Chevrel phase compounds can not only function as the host structures for reversible intercalation of a broad range of cations, but also exhibit high catalytic activity in electrochemical reduction reactions. Here we provide an overview of recent progress in the development of Chevrel phase materials including new understanding of structural features, synthetic methods, and electrochemical properties. A brief conclusion and perspectives on the future development of Chevrel phase materials are also provided.
After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic *** confusing mechanisms including atomic coordination,spatial c...
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After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic *** confusing mechanisms including atomic coordination,spatial configuration,and metal–metal atom interaction hinder the development and design of ***,a dual-centered Fe-Cu-N_(x)SAzyme exhibits excellent peroxidase(POD)-and catalase(CAT)-like activities with d-band center(ε_(d))coordination of Fe and Cu in multiple reaction stages,which plays a critical role in the adsorption of H_(2)O_(2)molecule and H_(2)O and O_(2)***,the dband center coordination,which can be represented byε_(d)(Fe)–ε_(d)(Cu)shifts,leads to the competition between one-side and bilateral adsorption,which determines the favorable reaction path with lower energy *** on experimental statistics,simulated formation energies,and reaction barriers,3 configurations,Fe-Cu-N6-I,Fe-Cu-N_(8)-II,and Fe-Cu-N_(8)-III,are modeled and ***,configuration-dependent catalytic selectivity and the competition between one-side and bilateral adsorption can be unveiled by d-band center coordination paradigm *** simulations suggest that the unsymmetrical charge distribution over the three Fe-Cu configurations could tune the adsorption strength compared with the counterparts FeN_(4)and CuN_(4).The present work provides a potential route for optimizing enzyme-like catalysis by designing the dual-or even triple-metal SAzymes,which demonstrates the large space to modulate the metal atomic configuration and interaction.
In this study,we successfully synthesized silicon nanotubes(Si-NTs)and silicon nanowires(Si-NWs)in a controllable manner using a catalyst-and template-free method through the direct electrolysis of SiO_(2)in a molten ...
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In this study,we successfully synthesized silicon nanotubes(Si-NTs)and silicon nanowires(Si-NWs)in a controllable manner using a catalyst-and template-free method through the direct electrolysis of SiO_(2)in a molten CaCl_(2)-CaO system,while also proposing a novel formation mechanism for ***-NWs are formed through electro-deoxidation when the cell voltage is within the range of CaO decomposition voltage and SiO_(2)decomposition *** subsequently adjusting the voltage to a value between the decomposition potentials of CaCl_(2)and CaO,in-situ electro-deoxidation of CaO takes place on the surface of the synthesized Si-NWs,leading to the formation of a Ca *** formation of Ca-Si diffusion couple leads to the creation of vacancies within the Si-NWs,as the outward diffusion rate of Si exceeds the inward diffusion rate of *** differential diffusion rates between Si and Ca in a diffusion couple exhibit an analogy to the Kirkendall *** vacancies gradually accumulate and merge,forming large voids,which ultimately result in the formation of hollow *** a subsequent dealloying process,the removal of the embedded calcium leads to the formation of *** the application of a carbon coating,the Si-NTs@C composite showcases a high initial discharge capacity of 3211 mAh·g^(-1)at 1.5 A·g^(-1)and exhibits exceptional long-term cycling stability,maintaining a capacity of 977 mAh·g^(-1)after 2000 cycles at 3.0 A·g^(-1).
Through nonlinear self-focusing, femtosecond pulses can propagate several kilometers beyond diffraction limits, forming an ionization channel in air known as a laser filaments. It has been demonstrated that in the wak...
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Through nonlinear self-focusing, femtosecond pulses can propagate several kilometers beyond diffraction limits, forming an ionization channel in air known as a laser filaments. It has been demonstrated that in the wake of the filament, aerosols can be effectively cleared to improve the transmission of subsequent laser pulses or secondary light sources, pertinent to applications in atmospheric sensing. However, the current understanding of aerosol clearing is founded on interactions with droplets to simulate fogs and clouds and thus does not extend to solid particles or atmospheric debris. Using optical trapping, we isolate both graphite and silica microparticles and directly measure the subsequent displacement caused by the filament using time-resolved shadowgraphy. The shock wave from the filament is demonstrated to propel particles away from the filament, directly contributing to atmospheric debris clearing. Particles exposed to the laser light in either the intense filament core or the surrounding energy reservoir are axially displaced along the beam path. It is found that the optomechanical properties of the particle largely influence the axial displacement induced by laser exposure through mechanisms such as radiation pressure, mass ejection from ablation or optical damage, and particle deagglomeration.
The RBaCo4O7 system is a prototype geometrically frustrated magnet in which kagome planes and triangular layers of Co-O tetrahedra interleave. For R=Y, an antiferromagnetic ground state is realized due to a frustratio...
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The RBaCo4O7 system is a prototype geometrically frustrated magnet in which kagome planes and triangular layers of Co-O tetrahedra interleave. For R=Y, an antiferromagnetic ground state is realized due to a frustration-breaking trigonal-orthorhombic phase transition. For R=Lu, however, a long-range ordered state has rarely, if ever, been reported despite a similar symmetry-breaking transition, albeit at a significantly lower temperature. To explore this dichotomy, we present a comprehensive magnetic and structural phase diagram for Y1–xLuxBaCo4O7, established through complementary neutron diffraction and magnetization measurements. Our results outline the phase evolution of the nuclear structures in response to changes in composition and temperature. The temperature of the trigonal (P31c) to orthorhombic (Pbn21) transition, Ts1, decreases monotonically with increasing Lu content from 310 K for x=0.0 to 110 K for x=1.0. In Lu-rich compositions (0.7≤x≤1.0), first-order structural transitions are observed with coexisting and competing orthorhombic Pbn21 and metastable monoclinic Cc phases. For the magnetically ordered Y-rich compositions, T- and x-dependent refinements of the magnetic structure reveal an antiferromagnetic “ribbonlike” arrangement of Co spin pairs in both the triangular and the kagome layers. A gradual suppression of long-range magnetic order is observed with increasing the Lu content, accompanied by the development of short-range magnetic correlations present in all the samples.
Powder crystallography is the experimental science of determining the structure of molecules provided in crystalline-powder form,by analyzing their x-ray diffraction(XRD)*** many materials are readily available as cry...
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Powder crystallography is the experimental science of determining the structure of molecules provided in crystalline-powder form,by analyzing their x-ray diffraction(XRD)*** many materials are readily available as crystalline powder,powder crystallography is of growing usefulness to many ***,powder crystallography does not have an analytically known solution,and therefore the structural inference typically involves a laborious process of iterative design,structural refinement,and domain knowledge of skilled experts.A key obstacle to fully automating the inference process computationally has been formulating the problem in an end-to-end quantitative form that is suitable for machine learning,while capturing the ambiguities around molecule orientation,symmetries,and reconstruction *** we present an ML approach for structure determination from powder diffraction *** works by estimating the electron density in a unit cell using a variational coordinate-based deep neural *** demonstrate the approach on computed powder x-ray diffraction(PXRD),along with partial chemical composition information,as *** evaluated on theoretically simulated data for the cubic and trigonal crystal systems,the system achieves up to 93.4%average similarity(as measured by structural similarity index)with the ground truth on unseen materials,both with known and partially-known chemical composition information,showing great promise for successful structure solution even from degraded and incomplete input *** approach does not presuppose a crystalline structure and the approach are readily extended to other situations such as nanomaterials and textured samples,paving the way to reconstruction of yet unresolved nanostructures.
The second law of thermodynamics asserts that energy diffuses from hot to *** resulting temperature gradients drive the efficiencies and failures in a plethora of ***,as the dimensionalities of materials shrink to the...
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The second law of thermodynamics asserts that energy diffuses from hot to *** resulting temperature gradients drive the efficiencies and failures in a plethora of ***,as the dimensionalities of materials shrink to the nanoscale regime,proper heat dissipation strategies becomemore challenging since the mean free paths of phonons become larger than the characteristic length *** leads to temperature gradients that are dependent on interfaces and boundaries,which ultimately can lead to severe thermal ***,we uncover a phenomenon which we refer to as‘phonon funneling’,that allows the control of phonon transport to preferentially direct phonon energy away from geometrically confined interfacial thermal bottlenecks and into localized colder *** phenomenon supersedes heat diffusion based on the macroscale temperature gradients,thus introducing a nanoscale regime in which boundary scattering increases the phonon thermal conductivity of thin films,an opposite effect than what is traditionally *** work advances the fundamental understanding of phonon transport at the nanoscale and the role of efficient scattering methods for enhancing thermal transport.
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