查看更多>>摘要：Electronic textiles,an emerging class of elec-tronic technology,offer exciting opportunities for seamless integration with the human body.Numerous applications have been developed based on electronic textiles.How-ever,researches on integrating multiple electronic textile-based devices are still few.In this study,we present a system integrated with an electrocardiogram monitoring sensor and an electroluminescence device based on stretchable and washable conductive microtextiles.The signal is acquired by an electrocardiograph amplifier and displayed by a dual-color electroluminescence device based on the processed results.The integrated electronic device has excellent moisture permeability and comfort for long-term wearing.The system reported in this study opens a new avenue for the application of electronic textiles in health monitoring,robotic prosthetics,and competitive sports.
查看更多>>摘要：High-performance type-Ⅱ superlattices of Ⅲ-Ⅴsemiconductor materials play an important role in the development and application of infrared optoelectronic devices.Improving the quality of epitaxial materials and clarifying the luminescent mechanism are of great signifi-cance for practical applications.In this work,strain-balanced and high-quality InAs/InxGa1-xAsySb1-y superlattices without lattice mismatch were achieved on InAs and GaSb substrates successfully.Superlattices grown on InAs sub-strate could exhibit higher crystal quality and surface flatness based on high-resolution X-ray diffraction(HRXRD)and atomic force microscopy(AFM)measurements'results.Moreover,the strain distribution phenomenon from geo-metric phase analysis indicates that fluctuations of alloy compositions in superlattices on GaSb substrate are more obvious.In addition,the optical properties of superlattices grown on different substrates are discussed systematically.Because of the difference in fluctuations of element com-position and interface roughness of superlattices on different substrates,the superlattices grown on InAs substrate would have higher integral intensity and narrower full-width at half maximum of long-wave infrared emission.Finally,the thermal quenching of emission intensity indicates that the superlattices grown on the InAs substrate have better recombination ability,which is beneficial for increasing the operating temperature of infrared optoelectronic devices based on this type of superlattices.
查看更多>>摘要：Defects engineering is an effective strategy for manipulating electromagnetic parameters and enhancing electromagnetic wave(EMW)absorption capacity.How-ever,the relationship between them is not clear,especially in solid solution structures.In this work,a series of(Cr1-x Vx)2AlC MAX phase solid solutions with layered structure were prepared via tuning the ratio of Cr and V to explore their EMW absorption performance.The experimental results indicated that the doping of V atoms at the M-site could effectively regulate its impedance matching and EMW absorption properties by introducing appropriate numbers of defects in the crystal,such as twin boundaries,dislocations and lattice distortions.Among them,if Cr∶V=3∶1,Cr1.5V0.5AlC,as radar absorption materials,could reach a strong reflection loss of-51.8 dB at the frequency of 12.8 GHz under an ultra-thin thickness of 1.3 mm.The reflection loss value could attain-10 dB in a wide fre-quency range of 2.7-18 GHz and thickness range of 1-5 mm.In addition,after high temperature and acid-al-kali immersion treatment,this sample still had good EMW absorption capability,and the effective absorption band-width was enhanced from 2.3 to 2.6 GHz after concen-trated acid immersion or 3.1 GHz after concentrated alkali immersion.This work has great reference significance for the research and development of high-performance MAX-based EMW absorption materials in harsh environments.
查看更多>>摘要：Photodynamic therapy(PDT),with high spa-tiotemporal selectivity,minimal side effects and less drug resistance,has emerged as a promising approach for the treatment of cancer.However,inadequate penetration depth and poor efficacy seriously restrict its practical application.To address these challenges,we developed a combined therapy platform(RENP@C/D-FA)based on rare-earth-doped nanoparticles(RENPs)with a structure of NaErF4∶Tm(0.5％)@NaYF4,on which photosensitizer Ce6(chlorin e6)and chemo-therapeutic drug(DOX)(doxoru-bicin)were loaded by encapsulating with an amphiphilic polymer distearoyl phosphatidylethanolamine-poly-ethylene glycol-folic acid(DSPE-PEG-FA).RENPs with NaErF4 as the matrix possess multiple excitation/emission peaks,enabling activation of PDT under near-infrared-Ⅱb(NIR-Ⅱb,1500-1700 nm)excitation and luminescence imaging in NIR-Ⅱb region by absorbing 808 nm near-in-frared photons.Furthermore,DOX can be selectively released in the acidic microenvironment of tumors.Bene-fiting from the tumor targeting capability of folic acid,this platform can successfully ablate tumor cells and inhibit tumor growth by combining PDT and chemotherapy.This innovative approach holds great promise as a powerful tool for cancer treatment,showing the potential to revolutionize PDT.
查看更多>>摘要：SnTe has received considerable attention as an environmentally friendly alternative to the representative thermoelectric material of PbTe.However,excessive hole carrier concentration in SnTe results in an extremely low Seebeck coefficient and high thermal conductivity,which makes it exhibit relatively inferior thermoelectric proper-ties.In this work,the thermoelectric performance of p-type SnTe is enhanced through regulating its energy band structures and reducing its electronic thermal conductivity by combining Bi doping with CdSe alloying.First,the carrier concentration of SnTe is successfully suppressed via Bi doping,which significantly decreases the electronic thermal conductivity.Then,the convergence and flattening of the valence bands by alloying CdSe effectively improves the effective mass of SnTe while restraining its carrier mobility.Finally,a maximum figure of merit(ZT)of～0.87 at 823 K and an average ZT of～0.51 at 300-823 K have been achieved in Sn0.96Bi0.04Te-5％CdSe.Our results indicate that decreasing the electronic thermal conductivity is an effective means of improving the per-formance of thermoelectric materials with a high carrier concentration.
查看更多>>摘要：In this work,a conventional HfO2 gate dielec-tric layer is replaced with a 3-nm ferroelectric(Fe)HZO layer in the gate stacks of advanced fin field-effect tran-sistors(FinFETs).Fe-induced characteristics,e.g.,negative drain induced barrier lowering(N-DIBL)and negative differential resistance(NDR),are clearly observed for both p-and n-type HZO-based FinFETs.These characteristics are attributed to the enhanced ferroelectricity of the 3-nm hafnium zirconium oxide(HZO)film,caused by Al doping from the TiAlC capping layer.This mechanism is verified for capacitors with structures similar to the FinFETs.Owing to the enhanced ferroelectricity and N-DIBL phe-nomenon,the drain current(IDs)of the HZO-FinFETs is greater than that of HfO2-FinFETs and obtained at a lower operating voltage.Accordingly,circuits based on HZO-FinFET achieve higher performance than those based on HfO2-FinFET at a low voltage drain(VDD),which indicates the application feasibility of the HZO-FinFETs in the ultra-low power integrated circuits.
查看更多>>摘要：Magnetic skyrmions emerge when the energy of ferromagnetic exchange interaction promoting parallel alignment of spins enters in competition with energies favoring non-collinear alignment of spins such as Dzyaloshinskii-Moriya interaction(DMI),long-rang dipole-dipole interaction(DDI),or higher-order exchange interactions.We perform an unbiased Monte Carlo simu-lation to study the DMI-based skyrmion nucleation and stabilization on the surface of magnetic nanotubular monolayer controlled by tuning constants of DDI(g)and next-nearest-neighbor antiferromagnetic exchange interac-tion(j')with appropriate balance.Without g and j',the loosely distributed skyrmions initially nucleate on the surface of nanotube approaching to the magnetic field(h)direction with increasing h in the intermediate range.Then,the skyrmion size,shape,density,distribution and crystal structure,as well as its driven field range,are tai-lored by g and j'.This work demonstrates the skyrmion nucleation mechanisms in three-dimensional magnetic nanostructures with curvature effect and multiple interactions,serving as a benchmark for a guide to exper-imentalists for preparation of samples in magnetic sky-rmion states.
查看更多>>摘要：A novel approach based on thermal diffusion was used to achieve controllable Mg content in A2B7-type La-Mg-Ni-based alloys.The formation mechanism of the A2B7-type phase as a result of the thermal diffusion process and the effect of Mg content on hydrogen storage perfor-mance were investigated.X-ray diffraction(XRD)patterns and Rietveld refinement results showed that increased Mg transformed the LaNi5 phase in the La0.74Sm0.03Y0.23-Ni4.32Al0.04 precursor alloy into a superlattice structure.Scanning electron microscopy(SEM)images showed that Mg was evenly distributed in the alloy bulk.Mg in the superlattice significantly inhibited the phase decomposition of the superlattice structure during the hydrogen absorp-tion/desorption cycles.An A2B7-type La0.57S-m0.02Y0.18Mg0.23Ni3.38Al0.03 alloy composed of Gd2Co7 and Ce2Ni7 phases was successfully synthesized.The pressure-composition isotherm profiles showed that the alloy had a hydrogen storage capacity as high as 1.73 wt％,with good cycling stability.After 50 cycles of hydrogen absorption/desorption,the alloy retained a hydrogen storage capacity of 1.45 wt％,with a capacity retention rate of up to 84.28％.The Mg thermal diffusion process thus provides a new approach for the controlled preparation of La-Mg-Ni-based alloys.
查看更多>>摘要：The exploration of efficient,long-lived and cost-effective transition metal catalysts is highly desirable for the practical hydrogen storage of magnesium hydride(MgH2)in sustainable energy devices.Herein,FeCoNiCrTi high-entropy alloy(HEA)nanosheets were prepared via a facile wet chemical ball milling strategy and they were introduced into MgH2 to boost the hydrogen storage per-formance.The refined HEA exhibited superior catalytic activity on MgH2.In contrast to additive-free MgH2,the initial desorption temperature of the constructed MgH2-HEA composite was reduced from 330.0 to 198.5 ℃ and a remarkable 51％reduction in the dehydrogenation activa-tion energy was achieved.Besides,the MgH2-HEA com-posite only required one-twentieth time of that consumed by pure MgH2 to absorb 5.0 wt％of H2 at 225 ℃.The synergy between the"hydrogen pumping"effect of Mg2Ni/Mg2NiH4 and Mg2Co/Mg2CoH5 couples,as well as the good dispersion of Fe,Cr and Ti on the surface of MgH2 contributed to the enhanced de/hydrogenation per-formance of the MgH2-HEA composites.This study fur-nishes important steering for the design and fabrication of multiple transition metal catalysts and may push the commercial application of magnesium-based hydrides one step forward.
查看更多>>摘要：The distinctive intrinsic heat treatment(IHT)originating from cyclic reheating in the laser-directed energy deposition(LDED)has attracted growing attention in recent years.In this investigation,simulations and experimental characterizations were performed to examine the impact of IHT on the microstructure and mechanical properties of LDED-fabricated CrCoNi medium-entropy alloy(MEA).The results show that the intensity of the IHT is proportional to the utilized laser energy density(LED).As the LED increased,significant dynamic recrystallization and grain refinement occurred within the alloy due to the enhanced intensity of IHT.However,the high LED leads to severe hot cracking within the as-built MEA,resulting in inferior ductility.By decreasing LED,the hot cracking was effectively eliminated.Meanwhile,low LED weakened the intensity of IHT and consequently inhibited kinetic con-ditions of dynamic recrystallization,resulting in a hetero-geneous grain structure characterized by multi-scale-sized grains.This structure provides significant hetero-deforma-tion-induced hardening during plastic deformation,enabling the alloy to have a sustainable work-hardening capacity.We expect that this work will have implications in taking full advantage of the unique IHT of the LDED process to fabricate MEAs with excellent metallurgical quality and mechanical performance.
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