Textiles for health and sporting activity monitoring are on the rise with the advent of smart portable wearables.The intention of this work is to design wireless monitoring wearables,based on widely available textiles...Textiles for health and sporting activity monitoring are on the rise with the advent of smart portable wearables.The intention of this work is to design wireless monitoring wearables,based on widely available textiles and low environmental impact production technologies.Herein we have developed a polymeric ink which is able to functionalize different types of textile fibers(including silver conducting fibers,cotton,and commercial textile)with poly pyrrole.These fibers were weaved together with a thinner silver conducting fiber and carbon fiber to form a touch-sensitive energy harvesting system that would generate an electric output when mechanical pressure is applied to it.Different prototypes were manufactured with loom weaving accessories to simulate real textile cloths.By simple touch,the prototypes produced a maximum voltage of 244 V and a maximum power density of 2.29 W m^(-2).The current generated is then transformed into a digital signal,which is further utilized for human motion or gesture monitorization.The system comprises a wireless block for the Internet of Things(IoT)applicability that will be eventually extended to future remote health and sports monitoring systems.展开更多
Achieving a superior strength-ductility combination for fcc single-phase high entropy alloys(HEAs)is challenging.The present work investigates the in-situ synthesis of Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)interstitial...Achieving a superior strength-ductility combination for fcc single-phase high entropy alloys(HEAs)is challenging.The present work investigates the in-situ synthesis of Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)interstitial solute-strengthened HEA containing 0.5 wt.%Nb(hereafter referred to as iHEA-Nb)using laser melt-ing deposition(LMD),aiming at simultaneously activating multiple strengthening mechanisms.The effect of Nb addition on the microstructure evolution,mechanical properties,strengthening and deformation mechanisms of the as-deposited iHEA-Nb samples was comprehensively evaluated.Multiple levels of het-erogeneity were observed in the LMD-deposited microstructure,including different grain sizes,cellular subgrain structures,various carbide precipitates,as well as elemental segregation.The incorporation of Nb atoms with a large radius leads to lattice distortion,reduces the average grain size,and increases the types and fractions of carbides,aiding in promoting solid solution strengthening,grain boundary strengthening,and precipitation strengthening.Tensile test results show that the Nb addition significantly increases the yield strength and ultimate tensile strength of the iHEA to 1140 and 1450 MPa,respectively,while maintaining the elongation over 30%.Deformation twins were generated in the tensile deformed samples,contributing to the occurrence of twinning-induced plasticity.This outstanding combination of strength and ductility exceeds that for most additively manufactured HEAs reported to date,demon-strating that the present in situ alloying strategy could provide significant advantages for developing and tailoring microstructures and balancing the mechanical properties of HEAs while avoiding conventional complex thermomechanical treatments.In addition,single-crystal micropillar compression tests revealed that although the twining activity is reduced by the Nb addition to the iHEA,the micromechanical prop-erties of grains with different orientations were significantly enhanced.展开更多
NiTiCu thin walls were produced by twin-wire arc additive manufacturing(T-WAAM)using commercial NiTi and Cu wires as the feedstock materials.This approach aims to solve the problems typically associated with large pha...NiTiCu thin walls were produced by twin-wire arc additive manufacturing(T-WAAM)using commercial NiTi and Cu wires as the feedstock materials.This approach aims to solve the problems typically associated with large phase transformation hysteresis in NiTi shape memory alloys.The microstructure,mechanical properties,and phase transformation behavior of the as-deposited NiTiCu alloy were comprehensively examined.The results re-vealed that the as-deposited NiTiCu alloy was well-formed,with its microstructure showed columnar,equiaxed,and needle-like grains,depending on the location within the deposited walls.The microhardness gradually in-creased from the first to the third layer.The Cu content was 20.80 at%,and Cu-based precipitates were formed in the as-deposited NiTiCu.The volume fractions and lattice parameters of the matrix and precipitates in the as-deposited NiTiCu material were analyzed using high-energy synchrotron X-ray diffraction.The martensitic phase was identified as a B19 crystal structure,and the as-deposited NiTiCu underwent a one-step B2-B19 phase transformation.The tensile strength and fracture strain were approximately 232 MPa and 3.72%,respectively.In particular,the addition of Cu narrowed the phase transformation hysteresis of the as-deposited NiTiCu alloy from 24.4 to 7.1◦C compared with conventional binary NiTi alloys.This study expands the potential of T-WAAM in modifying the phase transformation behavior of NiTi-based ternary alloys.展开更多
Dissimilar welding of NiTi and stainless steel(SS)for multifunctional device fabrication is challenging due to the brittle nature of intermetallic compounds(IMCs)that are formed in the weld zone.In this work,Ni and Nb...Dissimilar welding of NiTi and stainless steel(SS)for multifunctional device fabrication is challenging due to the brittle nature of intermetallic compounds(IMCs)that are formed in the weld zone.In this work,Ni and Nb interlayers were applied for the resistance spot welding(RSW)of NiTi and SS to replace the harmful Fe_(2)Ti phase and to restrict the mixing of dissimilar molten metals,respectively.Microstructural evolution and mechanical properties of the joints were investigated.It was shown that a conventional weld nugget was created in the absence of any interlayer in the welded joint suffering from traversed cracks due to the formation of brittle IMCs network in the fusion zone(FZ).By the addition of Ni from the interlayer,Fe_(2)Ti dominated weld nugget was efficaciously replaced by Ni_(3)Ti phase;however,the presence of the large pore and cracks reduced the effective joining area.The use of a Nb interlayer resulted in a fundamentally different joint,in which FZs at NiTi and SS sides separated by the unmolten Nb would suppress the mixing of dissimilar molten metals.Nb-containing eutectic structures with low brittleness formed at the interfaces,contributing to the enhancement of joint strength(increased by 38%on fracture load and 460%on energy absorption).A high-melting-point interlayer showed great potential to realize a reliable and high-performing RSWed NiTi-SS joint.展开更多
Flexible microelectronic devices have seen an increasing trend toward development of miniaturized,portable,and integrated devices as wearable electronics which have the requirement for being light weight,small in dime...Flexible microelectronic devices have seen an increasing trend toward development of miniaturized,portable,and integrated devices as wearable electronics which have the requirement for being light weight,small in dimension,and suppleness.Traditional three-dimensional(3D)and two-dimensional(2D)electronics gadgets fail to effectively comply with these necessities owing to their stiffness and large weights.Investigations have come up with a new family of one-dimensional(1D)flexible and fiber-based electronic devices(FBEDs)comprising power storage,energy-scavenging,implantable sensing,and flexible displays gadgets.However,development and manufacturing are still a challenge owing to their small radius,flexibility,low weight,weave ability and integration in textile electronics.This paper will provide a detailed review on the importance of substrates in electronic devices,intrinsic property requirements,fabrication classification and applications in energy harvesting,energy storage and other flexible electronic devices.Fiber-and textile-based electronic devices for bulk/scalable fabrications,encapsulation,and testing are reviewed and presented future research ideas to enhance the commercialization of these fiber-based electronics devices.展开更多
N-doped ZnO films were radio frequency(RF)sputtered on glass substrates and studied as a function of oxygen partial pressure(OPP)ranging from 3.0×10-4 to 9.5×10-3 Pa.X-ray diffraction patters confirmed the p...N-doped ZnO films were radio frequency(RF)sputtered on glass substrates and studied as a function of oxygen partial pressure(OPP)ranging from 3.0×10-4 to 9.5×10-3 Pa.X-ray diffraction patters confirmed the polycrystalline nature of the deposited films.The crystalline structure is influenced by the variation of OPP.Atomic force microscopy analysis confirmed the agglomeration of the neighboring spherical grains with a sharp increase of root mean square(RMS)roughness when the OPP is increased above 1.4×10-3 Pa.X-ray photoelectron spectroscopy analysis revealed that the incorporation of N content into the film is decreased with the increase of OPP,noticeably N 1s XPS peaks are hardly identified at 9.5×10-3 Pa.The average visible transmittance(380-700 nm) is increased with the increase of OPP(from～17%to 70%),and the optical absorption edge shifts towards the shorter wavelength.The films deposited with low OPP(≤3.0×10-4 Pa)show n-type conductivity and those deposited with high OPP(≥9.0×10-4 Pa)are highly resistive(>105Ω·cm)展开更多
Rhenium is a very scarce element, occurring in the Earth's crust mainly carried by molybdenite (MoS2). Due to a very low availability comparative to actual industrial demand, rhenium is nowadays one of the most ex...Rhenium is a very scarce element, occurring in the Earth's crust mainly carried by molybdenite (MoS2). Due to a very low availability comparative to actual industrial demand, rhenium is nowadays one of the most expensive mineral commodities and an increased interest is focused on ex- ploring residues resulting from a long-term mining, particularly of sulphide ore deposits. It is therefore noteworthy to assign the presence of rhenium (in a concentration up to 3 ppm) in the waste materials from the old sulphur factory at the abandoned mine of Sao Domingos (Iberian Pyrite Belt, Southeast Portugal), exploited since the Roman occupation of Iberia. Aiming at a potential sustainable recovery of rhenium as a by-product, X-ray near-edge absorption spectroscopy (XANES) was applied to clarify the Re-binding and mode of occurrence by comparing Re L3-edge XANES spectra obtained from mine waste samples (previously fully characterized by X-ray laboratory techniques) with similar spectra collected from Re-rich molybdenites (Mo1-xRexS2) and from Re-O model compounds configuring various valences and coordination environments of rhenium ions. Obtained results are commented, ruling out a possible Re-S binding and rather conforming with the binding of rhenium to oxygen in the analysed mine waste materials.展开更多
The aim of this work was to develop an active biopolymer based on chitosan by incorporating natural antioxidants.Five essential oils(ginger,rosemary,sage,tea tree and thyme)and six hydro-alcoholic extracts(from ginger...The aim of this work was to develop an active biopolymer based on chitosan by incorporating natural antioxidants.Five essential oils(ginger,rosemary,sage,tea tree and thyme)and six hydro-alcoholic extracts(from ginger,green and black tea,kenaf leaves,rosemary and sage plants)were tested.Migration assays were carried out to evaluate the films’activity,and total phenolic content and antioxidant activity were monitored in the simulant during storage.Interaction between natural compounds and polymeric matrix was evaluated by FTIR spectroscopy.The diffusion of the phenolic compounds was not detected in the films incorporated with hydro-alcoholic extracts(HAEs),indicating their entrapment in the chitosan.Migration was observed in the films with essential oils(EOs),and biobased films incorporated with ginger,sage or rosemary essential oils,presented the highest diffusion and antioxidant activity in the simulant,highlighting their functionality and potential to be used as food active packaging material.展开更多
Solid state NMR was successfully used to determine the proton spin-lattice relaxation time in the rotating frame (T1ρH) for systems based on polypropylene (PP) and PP with titanium dioxide (TiO<sub>2</sub>...Solid state NMR was successfully used to determine the proton spin-lattice relaxation time in the rotating frame (T1ρH) for systems based on polypropylene (PP) and PP with titanium dioxide (TiO<sub>2</sub>) organically modified or unmodified incorporated, in order to understand the molecular behavior of these systems. These techniques were employed in the samples organically modified and unmodified TiO<sub>2</sub> to investigate the effect of organic modification on the dispersion and distribution of the particles in the PP matrix. The results were analyzed in terms of the effect of the particles organic modified or not according to the intermolecular interaction in the composites. According to the T1ρH values, all composites showed at least two domains: the short values were related to the rigid part, which included the crystalline and amorphous phase constricted in it, while the longer times were attributed to the amorphous region, which had higher molecular mobility compared to the rigid region of the materials. The increase in the relaxation time parameter in the composites compared to the pure PP was associated to the strong interaction between titanium dioxide particles and the polymer chains. This effect was more pronounced for the systems containing organically modified TiO<sub>2</sub>. According to the results, it could be inferred that intermolecular interaction occurred in the CH<sub>2</sub> and CH groups, being more intense with CH<sub>2</sub> groups. Finally, the solid state NMR techniques were able to evaluate the molecular dynamics of those systems.展开更多
Advanced light management techniques can enhance the sunlight absorption of perovskite solar cells(PSCs).When located at the front,they may act as a UV barrier,which is paramount for protecting the perovskite layer ag...Advanced light management techniques can enhance the sunlight absorption of perovskite solar cells(PSCs).When located at the front,they may act as a UV barrier,which is paramount for protecting the perovskite layer against UVenabled degradation.Although it was recently shown that photonic structures such as Escher-like patterns could approach the theoretical Lambertian-limit of light trapping,it remains challenging to also implement UV protection properties for these diffractive structures while maintaining broadband absorption gains.Here,we propose a checkerboard(CB)tile pattern with designated UV photon conversion capability.Through a combined optical and electrical modeling approach,this photonic structure can increase photocurrent and power conversion efficiency in ultrathin PSCs by 25.9%and 28.2%,respectively.We further introduce a luminescent down-shifting encapsulant that converts the UV irradiation into Visible photons matching the solar cell absorption spectrum.To this end,experimentally obtained absorption and emission profiles of state-of-the-art down-shifting materials(i.e.,lanthanidebased organic-inorganic hybrids)are used to predict potential gains from harnessing the UV energy.We demonstrate that at least 94%of the impinging UV radiation can be effectively converted into the Visible spectral range.Photonic protection from high-energy photons contributes to the market deployment of perovskite solar cell technology,and may become crucial for Space applications under AM0 illumination.By combining light trapping with luminescent downshifting layers,this work unravels a potential photonic solution to overcome UV degradation in PSCs while circumventing optical losses in ultrathin cells,thus improving both performance and stability.展开更多
The new properties of engineered nanoparti- cles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have ...The new properties of engineered nanoparti- cles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have been used extensively for a wide range of applica- tions, e.g, self-cleaning surface coatings, solar cells, water treatment agents, topical sunscreens. Within this scenario increased environmental exposure can be expected but data on the ecotoxicological evaluation ofnanoparticles are still scarce. The main purpose of this work was the evaluation of effects of TiO2 nanoparticles in several organisms, covering different trophic levels, using a battery of aquatic assays. Using fish as a vertebrate model organism tissue histological and ultrastructural observations and the stress enzyme activity were also studied. TiO2 nanoparticles （Aeroxide~ P25）, two phase composition ofanatase （65%） and rutile （35%） with an average particle size value of 27.64-11 nm were used. Results on the ECs0 for the tested aquatic organisms showed toxicity for the bacteria, the algae and the crustacean, being the algae the most sensitive tested organism. The aquatic plant Lemna minor showed no effect on growth. The fish Carassius auratus showed no effect on a 21 day survival test, though at a biochemical level the cytosolic Glutathione-S-Transferase total activity, in intestines, showed a general significant decrease （p〈0.05） after 14 days of exposure for all tested concentrations. The presence of TiO2 nanoparticles aggregates were observed in the intestine lumen but their internalization by intestine cells could not be confirmed.展开更多
Insightful knowledge on quantum nanostructured materials is paramount to engineer and exploit their vast gamut of applications.Here,a formalism based on the single-band effective mass equation was developed to determi...Insightful knowledge on quantum nanostructured materials is paramount to engineer and exploit their vast gamut of applications.Here,a formalism based on the single-band effective mass equation was developed to determine the light absorption of colloidal quantum dots(CQDs)embedded in a wider bandgap semiconductor host,employing only three parameters(dots/host potential barrier,effective mass,and QD size).It was ascertained how to tune such parameters to design the energy level structure and consequent optical response.Our findings show that the CQD size has the biggest effect on the number and energy of the confined levels,while the potential barrier causes a linear shift of their values.While smaller QDs allow wider energetic separation between levels(as desired for most quantumbased technologies),the larger dots with higher number of levels are those that exhibit the strongest absorption.Nevertheless,it was unprecedently shown that such quantum-enabled absorption coefficients can reach the levels(10^(4)–10^(5) cm^(−1))of bulk semiconductors.展开更多
基金the project BRIGHT(Project reference:MERA-NET3/0004/2021)financed by national funds from FCT-Fundacao para a Ciência e a Tecnologia,I.P.,in the scope of the projects LA/P/0037/2020,UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures,Nanomodelling and Nanofabrication-i3N+6 种基金the support from the i3N-FCT-Portuguese Foundation for Science and Technology through the Ph.D.(Scholarship grant no.UI/BD/151288/2021)also partially supported by European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreements number 952169(SYNERGY,H2020-WIDESPREAD-2020-5,CSA)and 101008701(EMERGE,H2020-INFRAIA-2020-1),and 101070255(REFORM,HORIZON-C L4-2021-DIGITAL-EMERGING-01)also supported by LISBOA-05-3559-FSE-000007CENTRO-04-3559FSE-000094 operationsco-funded by the Lisboa 2020,Centro 2020 programme,Portugal 2020,European Union,through the European Social FundFunda??o para a Ciência e Tecnologia(FCT)Agência Nacional de Inovacao(ANI)。
文摘Textiles for health and sporting activity monitoring are on the rise with the advent of smart portable wearables.The intention of this work is to design wireless monitoring wearables,based on widely available textiles and low environmental impact production technologies.Herein we have developed a polymeric ink which is able to functionalize different types of textile fibers(including silver conducting fibers,cotton,and commercial textile)with poly pyrrole.These fibers were weaved together with a thinner silver conducting fiber and carbon fiber to form a touch-sensitive energy harvesting system that would generate an electric output when mechanical pressure is applied to it.Different prototypes were manufactured with loom weaving accessories to simulate real textile cloths.By simple touch,the prototypes produced a maximum voltage of 244 V and a maximum power density of 2.29 W m^(-2).The current generated is then transformed into a digital signal,which is further utilized for human motion or gesture monitorization.The system comprises a wireless block for the Internet of Things(IoT)applicability that will be eventually extended to future remote health and sports monitoring systems.
基金WZ acknowledges the China Scholarship Council for her PhD grant(CSC No.201906250212)YP acknowledges financial support by Samenwerkingsverband Noord-Nederland(SNN)within the pro-gram“3D Print Kompas”+8 种基金JPO and JS acknowledge Fundação para a Ciência e a Tecnologia(FCT-MCTES)for its financial support via the project UID/00667/2020(UNIDEMI)JPO acknowledges fund-ing by national funds from FCT-Fundação para a Ciência e a Tecnologia,I.P.,in the scope of the projects NosLA/P/0037/2020,UIDP/50025/2020,and UIDB/50025/2020 of the Associate Labo-ratory Institute of Nanostructures,Nanomodelling and Nanofabri-cation–i3N.JS acknowledges the China Scholarship Council for her PhD grant(CSC No.201808320394)The authors acknowledge DESY(Hamburg,Germany),a member of the Helmholtz Associ-ation HGF,for the provision of experimental facilities.Beamtime was allocated for proposal I-20210899 ECThe research leading to this result has been supported by the project CALIPSOplus un-der Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020SF acknowledges fi-nancial support from the National Natural Science Foundation of China(No.52105318 and 52311530340)"Chunhui Plan"Col-laborative Research Project of the Ministry of Education,China(HZKY20220023)This research was carried out under project number S17024o in the framework of the Partnership Program of the Materials Innova-tion Institute M2i(www.m2i.nl)the Netherlands Organization for Scientific Research(www.nwo.nl).
文摘Achieving a superior strength-ductility combination for fcc single-phase high entropy alloys(HEAs)is challenging.The present work investigates the in-situ synthesis of Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)interstitial solute-strengthened HEA containing 0.5 wt.%Nb(hereafter referred to as iHEA-Nb)using laser melt-ing deposition(LMD),aiming at simultaneously activating multiple strengthening mechanisms.The effect of Nb addition on the microstructure evolution,mechanical properties,strengthening and deformation mechanisms of the as-deposited iHEA-Nb samples was comprehensively evaluated.Multiple levels of het-erogeneity were observed in the LMD-deposited microstructure,including different grain sizes,cellular subgrain structures,various carbide precipitates,as well as elemental segregation.The incorporation of Nb atoms with a large radius leads to lattice distortion,reduces the average grain size,and increases the types and fractions of carbides,aiding in promoting solid solution strengthening,grain boundary strengthening,and precipitation strengthening.Tensile test results show that the Nb addition significantly increases the yield strength and ultimate tensile strength of the iHEA to 1140 and 1450 MPa,respectively,while maintaining the elongation over 30%.Deformation twins were generated in the tensile deformed samples,contributing to the occurrence of twinning-induced plasticity.This outstanding combination of strength and ductility exceeds that for most additively manufactured HEAs reported to date,demon-strating that the present in situ alloying strategy could provide significant advantages for developing and tailoring microstructures and balancing the mechanical properties of HEAs while avoiding conventional complex thermomechanical treatments.In addition,single-crystal micropillar compression tests revealed that although the twining activity is reduced by the Nb addition to the iHEA,the micromechanical prop-erties of grains with different orientations were significantly enhanced.
基金supported by National Natural Science Founda-tion of China(Grant No.52175292)Science and Technology Project of Sichuan Province(Grant Nos.23NSFJQ0064,2022YFQ0058)+2 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.2021B1515140048)JPO and JS acknowledge the funding by na-tional funds from Fundação para a Ciência e a Tecnologia(FCT),I.P.,within the scope of projects LA/P/0037/2020,UIDP/50025/2020,and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostruc-tures,Nanomodelling,and Nanofabrication-i3NDESY(Hamburg,Germany),a member of the Helmholtz Associa-tion HGF,for providing the experimental facilities.Part of this study was conducted at PETRA III.The research leading to this result was sup-ported by project CALIPSOplus under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.
文摘NiTiCu thin walls were produced by twin-wire arc additive manufacturing(T-WAAM)using commercial NiTi and Cu wires as the feedstock materials.This approach aims to solve the problems typically associated with large phase transformation hysteresis in NiTi shape memory alloys.The microstructure,mechanical properties,and phase transformation behavior of the as-deposited NiTiCu alloy were comprehensively examined.The results re-vealed that the as-deposited NiTiCu alloy was well-formed,with its microstructure showed columnar,equiaxed,and needle-like grains,depending on the location within the deposited walls.The microhardness gradually in-creased from the first to the third layer.The Cu content was 20.80 at%,and Cu-based precipitates were formed in the as-deposited NiTiCu.The volume fractions and lattice parameters of the matrix and precipitates in the as-deposited NiTiCu material were analyzed using high-energy synchrotron X-ray diffraction.The martensitic phase was identified as a B19 crystal structure,and the as-deposited NiTiCu underwent a one-step B2-B19 phase transformation.The tensile strength and fracture strain were approximately 232 MPa and 3.72%,respectively.In particular,the addition of Cu narrowed the phase transformation hysteresis of the as-deposited NiTiCu alloy from 24.4 to 7.1◦C compared with conventional binary NiTi alloys.This study expands the potential of T-WAAM in modifying the phase transformation behavior of NiTi-based ternary alloys.
基金Natural Sciences and Engineering Research Council of Canada(NSERC)Canada Research Chairs(CRC)+1 种基金K.Z.acknowledges support from China Scholarship Council(CSC)J.P.O.acknowledges funding by national funds from FCT-Fundação para a Ciência e a Tecnologia,I.P.,in the scope of the projects LA/P/0037/2020,UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures,Nanomodelling and Nanofabrication–i3N.
文摘Dissimilar welding of NiTi and stainless steel(SS)for multifunctional device fabrication is challenging due to the brittle nature of intermetallic compounds(IMCs)that are formed in the weld zone.In this work,Ni and Nb interlayers were applied for the resistance spot welding(RSW)of NiTi and SS to replace the harmful Fe_(2)Ti phase and to restrict the mixing of dissimilar molten metals,respectively.Microstructural evolution and mechanical properties of the joints were investigated.It was shown that a conventional weld nugget was created in the absence of any interlayer in the welded joint suffering from traversed cracks due to the formation of brittle IMCs network in the fusion zone(FZ).By the addition of Ni from the interlayer,Fe_(2)Ti dominated weld nugget was efficaciously replaced by Ni_(3)Ti phase;however,the presence of the large pore and cracks reduced the effective joining area.The use of a Nb interlayer resulted in a fundamentally different joint,in which FZs at NiTi and SS sides separated by the unmolten Nb would suppress the mixing of dissimilar molten metals.Nb-containing eutectic structures with low brittleness formed at the interfaces,contributing to the enhancement of joint strength(increased by 38%on fracture load and 460%on energy absorption).A high-melting-point interlayer showed great potential to realize a reliable and high-performing RSWed NiTi-SS joint.
基金National Funds through FCT–Portuguese Foundation for Science and Technology under the projects PTDC/CTM-CTM/1571/2020(All-Fi BRE),LA/P/0037/2020,UIDP/50025/2020 and UIDB/50025/2020(CENIMAT/I3N)by ERC-Co G-2014,CapTherPV,647596。
文摘Flexible microelectronic devices have seen an increasing trend toward development of miniaturized,portable,and integrated devices as wearable electronics which have the requirement for being light weight,small in dimension,and suppleness.Traditional three-dimensional(3D)and two-dimensional(2D)electronics gadgets fail to effectively comply with these necessities owing to their stiffness and large weights.Investigations have come up with a new family of one-dimensional(1D)flexible and fiber-based electronic devices(FBEDs)comprising power storage,energy-scavenging,implantable sensing,and flexible displays gadgets.However,development and manufacturing are still a challenge owing to their small radius,flexibility,low weight,weave ability and integration in textile electronics.This paper will provide a detailed review on the importance of substrates in electronic devices,intrinsic property requirements,fabrication classification and applications in energy harvesting,energy storage and other flexible electronic devices.Fiber-and textile-based electronic devices for bulk/scalable fabrications,encapsulation,and testing are reviewed and presented future research ideas to enhance the commercialization of these fiber-based electronics devices.
基金the Portuguese Ministry of Science and Technology(FCT-MCTES)for offering post-doctoral fellowships through the grants SFRH/BPD/34542/2007 and SFRH/BPD/35055/2007,respectivelyfinanced by FCT-MCTES through CENIMAT-I3N
文摘N-doped ZnO films were radio frequency(RF)sputtered on glass substrates and studied as a function of oxygen partial pressure(OPP)ranging from 3.0×10-4 to 9.5×10-3 Pa.X-ray diffraction patters confirmed the polycrystalline nature of the deposited films.The crystalline structure is influenced by the variation of OPP.Atomic force microscopy analysis confirmed the agglomeration of the neighboring spherical grains with a sharp increase of root mean square(RMS)roughness when the OPP is increased above 1.4×10-3 Pa.X-ray photoelectron spectroscopy analysis revealed that the incorporation of N content into the film is decreased with the increase of OPP,noticeably N 1s XPS peaks are hardly identified at 9.5×10-3 Pa.The average visible transmittance(380-700 nm) is increased with the increase of OPP(from～17%to 70%),and the optical absorption edge shifts towards the shorter wavelength.The films deposited with low OPP(≤3.0×10-4 Pa)show n-type conductivity and those deposited with high OPP(≥9.0×10-4 Pa)are highly resistive(>105Ω·cm)
基金the project MinReMol(Ref.EXPL/AAG-REC/0978/2012),financed by FEDER Funds through the Operational Program on Competitive Factors(COMPETE:FCOMP-01-0124-FEDER-027516)by national funds through the Portuguese Foundation for Science and Technology(FCT-MCTES)support of FCT-MCTES through the Strategic Project LA25-2011-2012(ref.PEst-C/CTM/LA0025/2011).
文摘Rhenium is a very scarce element, occurring in the Earth's crust mainly carried by molybdenite (MoS2). Due to a very low availability comparative to actual industrial demand, rhenium is nowadays one of the most expensive mineral commodities and an increased interest is focused on ex- ploring residues resulting from a long-term mining, particularly of sulphide ore deposits. It is therefore noteworthy to assign the presence of rhenium (in a concentration up to 3 ppm) in the waste materials from the old sulphur factory at the abandoned mine of Sao Domingos (Iberian Pyrite Belt, Southeast Portugal), exploited since the Roman occupation of Iberia. Aiming at a potential sustainable recovery of rhenium as a by-product, X-ray near-edge absorption spectroscopy (XANES) was applied to clarify the Re-binding and mode of occurrence by comparing Re L3-edge XANES spectra obtained from mine waste samples (previously fully characterized by X-ray laboratory techniques) with similar spectra collected from Re-rich molybdenites (Mo1-xRexS2) and from Re-O model compounds configuring various valences and coordination environments of rhenium ions. Obtained results are commented, ruling out a possible Re-S binding and rather conforming with the binding of rhenium to oxygen in the analysed mine waste materials.
文摘The aim of this work was to develop an active biopolymer based on chitosan by incorporating natural antioxidants.Five essential oils(ginger,rosemary,sage,tea tree and thyme)and six hydro-alcoholic extracts(from ginger,green and black tea,kenaf leaves,rosemary and sage plants)were tested.Migration assays were carried out to evaluate the films’activity,and total phenolic content and antioxidant activity were monitored in the simulant during storage.Interaction between natural compounds and polymeric matrix was evaluated by FTIR spectroscopy.The diffusion of the phenolic compounds was not detected in the films incorporated with hydro-alcoholic extracts(HAEs),indicating their entrapment in the chitosan.Migration was observed in the films with essential oils(EOs),and biobased films incorporated with ginger,sage or rosemary essential oils,presented the highest diffusion and antioxidant activity in the simulant,highlighting their functionality and potential to be used as food active packaging material.
文摘Solid state NMR was successfully used to determine the proton spin-lattice relaxation time in the rotating frame (T1ρH) for systems based on polypropylene (PP) and PP with titanium dioxide (TiO<sub>2</sub>) organically modified or unmodified incorporated, in order to understand the molecular behavior of these systems. These techniques were employed in the samples organically modified and unmodified TiO<sub>2</sub> to investigate the effect of organic modification on the dispersion and distribution of the particles in the PP matrix. The results were analyzed in terms of the effect of the particles organic modified or not according to the intermolecular interaction in the composites. According to the T1ρH values, all composites showed at least two domains: the short values were related to the rigid part, which included the crystalline and amorphous phase constricted in it, while the longer times were attributed to the amorphous region, which had higher molecular mobility compared to the rigid region of the materials. The increase in the relaxation time parameter in the composites compared to the pure PP was associated to the strong interaction between titanium dioxide particles and the polymer chains. This effect was more pronounced for the systems containing organically modified TiO<sub>2</sub>. According to the results, it could be inferred that intermolecular interaction occurred in the CH<sub>2</sub> and CH groups, being more intense with CH<sub>2</sub> groups. Finally, the solid state NMR techniques were able to evaluate the molecular dynamics of those systems.
基金financed by national funds from FCT(Fundação para a Ciência e Tecnologia,I.P.)in the scope of the projects LA/P/0037/2020,UIDP/50025/2020,and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures,Nanomodelling,and Nanofabrication-i3N,and the FCT,I.P.project SpaceFlex(2022.01610.PTDC)as well as by M-ECO2 project(Industrial cluster for advanced biofuel production,Ref.C644930471-00000041)cofinanced by PRR-Recovery and Resilience Plan of the European Union(Next Generation EU)+3 种基金This work was also developed within the scope of the projects:CICECO-Aveiro Institute of Materials,UIDB/50011/2020,UIDP/50011/2020,and LA/P/0006/2020 financed by national funds through the FCT,I.P.(PIDDAC)S.H.acknowledges the support from FCT,I.P.through the AdvaMTech Ph.D.program scholarship PD/BD/143031/2018S.H.and S.Y.acknowledge the support of the SRP-JRP project(non-EE046)M.A.also acknowledges the support from FCT,I.P.through the Ph.D.scholarship grant SFRH/BD/148078/2019.
文摘Advanced light management techniques can enhance the sunlight absorption of perovskite solar cells(PSCs).When located at the front,they may act as a UV barrier,which is paramount for protecting the perovskite layer against UVenabled degradation.Although it was recently shown that photonic structures such as Escher-like patterns could approach the theoretical Lambertian-limit of light trapping,it remains challenging to also implement UV protection properties for these diffractive structures while maintaining broadband absorption gains.Here,we propose a checkerboard(CB)tile pattern with designated UV photon conversion capability.Through a combined optical and electrical modeling approach,this photonic structure can increase photocurrent and power conversion efficiency in ultrathin PSCs by 25.9%and 28.2%,respectively.We further introduce a luminescent down-shifting encapsulant that converts the UV irradiation into Visible photons matching the solar cell absorption spectrum.To this end,experimentally obtained absorption and emission profiles of state-of-the-art down-shifting materials(i.e.,lanthanidebased organic-inorganic hybrids)are used to predict potential gains from harnessing the UV energy.We demonstrate that at least 94%of the impinging UV radiation can be effectively converted into the Visible spectral range.Photonic protection from high-energy photons contributes to the market deployment of perovskite solar cell technology,and may become crucial for Space applications under AM0 illumination.By combining light trapping with luminescent downshifting layers,this work unravels a potential photonic solution to overcome UV degradation in PSCs while circumventing optical losses in ultrathin cells,thus improving both performance and stability.
文摘The new properties of engineered nanoparti- cles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have been used extensively for a wide range of applica- tions, e.g, self-cleaning surface coatings, solar cells, water treatment agents, topical sunscreens. Within this scenario increased environmental exposure can be expected but data on the ecotoxicological evaluation ofnanoparticles are still scarce. The main purpose of this work was the evaluation of effects of TiO2 nanoparticles in several organisms, covering different trophic levels, using a battery of aquatic assays. Using fish as a vertebrate model organism tissue histological and ultrastructural observations and the stress enzyme activity were also studied. TiO2 nanoparticles （Aeroxide~ P25）, two phase composition ofanatase （65%） and rutile （35%） with an average particle size value of 27.64-11 nm were used. Results on the ECs0 for the tested aquatic organisms showed toxicity for the bacteria, the algae and the crustacean, being the algae the most sensitive tested organism. The aquatic plant Lemna minor showed no effect on growth. The fish Carassius auratus showed no effect on a 21 day survival test, though at a biochemical level the cytosolic Glutathione-S-Transferase total activity, in intestines, showed a general significant decrease （p〈0.05） after 14 days of exposure for all tested concentrations. The presence of TiO2 nanoparticles aggregates were observed in the intestine lumen but their internalization by intestine cells could not be confirmed.
基金This work was funded by FCT(Fundação para a Ciência e Tecnologia,I.P.)under the projects UIDB/50025/2020SuperSolar(PTDC/NAN-OPT/28430/2017)+2 种基金TACIT(PTCD/NAN-OPT/28837/2017)M.Alexandre also acknowledges funding by FCT,I.P.through the grant SFRH/BD/148078/2019We also acknowledge the support of SYNERGY,H2020-WIDESPREAD-2020-5,CSA,proposal n°952169.
文摘Insightful knowledge on quantum nanostructured materials is paramount to engineer and exploit their vast gamut of applications.Here,a formalism based on the single-band effective mass equation was developed to determine the light absorption of colloidal quantum dots(CQDs)embedded in a wider bandgap semiconductor host,employing only three parameters(dots/host potential barrier,effective mass,and QD size).It was ascertained how to tune such parameters to design the energy level structure and consequent optical response.Our findings show that the CQD size has the biggest effect on the number and energy of the confined levels,while the potential barrier causes a linear shift of their values.While smaller QDs allow wider energetic separation between levels(as desired for most quantumbased technologies),the larger dots with higher number of levels are those that exhibit the strongest absorption.Nevertheless,it was unprecedently shown that such quantum-enabled absorption coefficients can reach the levels(10^(4)–10^(5) cm^(−1))of bulk semiconductors.
