Although hot-rolled La(Fe,Co,Si)13-based alloys are promising magnetocaloric materials for solidstate cooling with near-net shaping capabilities,their underlying hot deformation mechanisms remain largely unexplored.In...Although hot-rolled La(Fe,Co,Si)13-based alloys are promising magnetocaloric materials for solidstate cooling with near-net shaping capabilities,their underlying hot deformation mechanisms remain largely unexplored.In this study,a comprehensive and systematic investigation was conducted,by encompassing the analysis of hot deformation mechanisms,along with the microstructure evolution and magnetoc aloric properties of hot-rolled La-Fe-Co-Si alloy.The La_(1.05)Fe_(11.2)Co_(0.7)Si_(1.38)alloy was examined using multiscale mechanical analysis to assess the effects of temperature.A series of macroscale hot compression and microscale nanoindentation tests were performed to access global and local mechanical properties,including variations in hardness and indentation modulus of the primaryα-Fe and secondary 1:1:1 phases up to 800℃.A significant decrease in hardness and elastic recovery of the secondary phase was observed between 600and 800℃,above half of its melting point(1113℃),suggesting pronounced flow softening in both theα-Fe and 1:1:1 phases.Additionally,a novel multi-step annealing process was introduced for hot-rolled La-Fe-Co-Si alloys,involving partial transient liquid-phase diffusion in the 1:1:1 phase to address deformation-induced defects,such as residualα-Fe and lattice distortions in the 1:13 phase,which have not been previously reported.As a result,a primary La(Fe,Co,Si)13phase with a volume fraction of97.5%was achieved after multi-step annealing,compared to 87.5%using conventional annealing.Correspondingly,the magnetocaloric properties were restored,with the Curie temperature(TC)recovering from 276 to 268 K and the maximum magnetic entropy change(ΔSM)increasing from 7.56 to 8.67 J kg^(-1)K^(-1)under a 2 T magnetic field.展开更多
ECO-Al alloys are introduced as a game-changer for the aluminum industry and it is of utmost importance to determine the role of alloying elements in their processing characteristics.In this study,the effects of Cr on...ECO-Al alloys are introduced as a game-changer for the aluminum industry and it is of utmost importance to determine the role of alloying elements in their processing characteristics.In this study,the effects of Cr on the hot deformation behavior of newly-developed ECO-7175 alloy were investigated.ECO-7175 samples with and without Cr were hot-compressed using a Gleeble simulator(temperature range of 350−500℃ and strain rates of 0.001−1 s^(−1)).The results were used to study the constitutive equations,the processing maps,and the microstructural evolution of the alloys.In Cr-containing alloy,the analysis of the deformation activation energy reveals that the rate-controlling mechanisms of the deformation change gradually from self-diffusion of Al(or diffusion of Mg in Al)to diffusion of Cr in Al by decreasing the Zener−Hollomon parameter.The analysis of the processing maps of Cr-containing alloy shows that the dynamic recrystallization(DRX)zone is limited to the deformation at high temperatures and low strain rates and expands with increasing applied strain.On the other hand,it is found that the self-diffusion of Al(or Mg in Al)is the only rate-controlling mechanism during hot deformation of Cr-free alloy in all processing conditions and its DRX zone is independent of the plastic strain.展开更多
Nb tubes were fabricated through hydrostatic extrusion at extrusion ratios of 3.1 and 6.1 at ambient temperature,and then their microstructure,texture,and Vickers hardness were investigated based on electron back-scat...Nb tubes were fabricated through hydrostatic extrusion at extrusion ratios of 3.1 and 6.1 at ambient temperature,and then their microstructure,texture,and Vickers hardness were investigated based on electron back-scattered diffraction(EBSD)data.The fraction of low-angle boundaries(LABs)largely decreased with a sharp decrease in mean grain sizes after hydrostatic extrusion and was not proportional to extrusion ratios,assuming that mixed-asymmetrical junctions forming LABs dissociate at high extrusion ratios from the external stress(>981 MPa)with thermal activation by the generated heat.The correlation between grain size and Vickers hardness followed the Hall−Petch relationship despite the texture gradient of theá111ñcyclic fiber textural microstructure at low extrusion ratios and theá100ñtrue fiber textural microstructure at high extrusion ratios.The increase in hydrostatic pressure on the Nb tubes contributed to texture evolution in terms of extrusion ratios due to the difference between{110}<111>and{112}<111>components based on EBSD data.展开更多
The third-order optical nonlinearities and responses of a squarylium dye, 2,4-di-3-guaiazulenyl-1,3-dihydroxycyclobutenediylium dihydroxide, in tetrahydrofuran （THF） solution and in polystyrene （PS） coating films ...The third-order optical nonlinearities and responses of a squarylium dye, 2,4-di-3-guaiazulenyl-1,3-dihydroxycyclobutenediylium dihydroxide, in tetrahydrofuran （THF） solution and in polystyrene （PS） coating films are measured by the femtosecond degenerate four-wave mixing technique under resonant conditions. The molecular hyperpolarizability γ of the squarylium dye in the THF solution is determined to be 3.0 × 10^-29 esu at 764 nm, and its electronic component γe is determined to be 1.1 × 10^-29 esu. The third-order nonlinear susceptibility X^（3） of one of the present PS coating films containing the squarylium dye is as high as 3.1 × 10^-8 esu at 80Ohm, and its electronic component Xe^（3） is 1.3 × 10^-8 esu.展开更多
As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potentia...As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].展开更多
A squarylium dye is dissolved in 4-cyano-4＇-pentylbiphenyl （SCB） and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB lay...A squarylium dye is dissolved in 4-cyano-4＇-pentylbiphenyl （SCB） and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB layers exhibit high anisotropy. The third-order nonlinear optical responses and susceptibilities X^（3）e of squarylium dye in 5CB are measured with light polarizations parallel and perpendicular to the orientational direction by the resonant femtosecond degenerate four-wave mixing （DFWM） technique. Temporal profiles of the DFWM signal of the oriented squarylium dye-5CB layers with light polarizations parallel and perpendicular to the orientational direction are measured with a time resolution of 0.3ps （FWHM）, and are found to consist of two components, i.e., the coherent instantaneous nonlinear response and slow response due to the formation of excited molecules. A high anisotropic ratio of x^（3）e, 10.8 ：k 1.2, is observed for the oriented layers.展开更多
Surface functionalization of suspended single-walled carbon nanotubes(SWNTs) using metal(Au) nanoparticles(NPs) is reported.SWNTs are grown on three-dimensionally patterned substrates by thermal chemical vapor deposit...Surface functionalization of suspended single-walled carbon nanotubes(SWNTs) using metal(Au) nanoparticles(NPs) is reported.SWNTs are grown on three-dimensionally patterned substrates by thermal chemical vapor deposition and successfully functionalized with Au NPs.Ethylendiamine is mainly used to functionalize SWNTs surface with amino groups before introducing Au NPs.From Raman scattering spectroscopy of the Au-functionalized suspended SWNTs,enhanced Raman scattering properties are obtained.The results suggest that the attached Au NPs may contribute to the enhancement of resonant phenomena.By measuring the electric properties after each functionalization process,it is found that Au NPs act as electron acceptor to the amine functionalized SWNTs.展开更多
Regeneration of pure water is an important issue not only for the healthy life but also for the fine control of precise processes in various industries.One important issue in ultrahigh purified water is to reduce the ...Regeneration of pure water is an important issue not only for the healthy life but also for the fine control of precise processes in various industries.One important issue in ultrahigh purified water is to reduce the amount of total organic carbon(TOC).Herein,we introduce a new approach to reduce the TOC using the surface silanized nanoparticles,in which the magnetic nanoparticles(mNPs)are silanized and then complexed with ion exchange resin(IER)beads.The Fe3O4 mNPs are surface modified by using high concentrated vinyltrimethoxysilane(VTMS)and then adhered on the surface of IER beads.The surface modified mNPs have a thick-shell of polysiloxane layer varying from 5 to 22 nm depending on the amount of VTMS used,which leads the significant increase of specific surface area.The IER beads embedding VTMS-silanized mNPs achieves about 7μg/L of the TOC level in ultrapure water system,which is two orders less than 228μg/L of the feeding water and one order less than 96μg/L from the system using pristine IER beads.This result is mainly attributed to the polysiloxane layer forming broccoli-like surface structure and some part by the vinyl group of VTMS exposed to the amines in the water.展开更多
Single-phase bcc-ferrite in an interstitial free(IF)steel was deformed to different strains in a wide range from low to high strains(ε=1–7)by torsion under different Zener-Hollomon(Z)conditions.The specimens were ra...Single-phase bcc-ferrite in an interstitial free(IF)steel was deformed to different strains in a wide range from low to high strains(ε=1–7)by torsion under different Zener-Hollomon(Z)conditions.The specimens were rapidly quenched after the torsion to preserve microstructures formed under different deformation conditions.The results showed that during high-Z(low-temperature)deformation,grains were subdivided by geometrically necessary boundaries(GNBs)via the grain subdivision mechanism.Deformation to high strains(ε>5)led to the ultrafine lamellar structures(with grain sizes<1μm)mainly composed of GNBs having high misorientation angles.Decreasing Z with increasing temperature and/or decreasing strain rate accelerated thermally activated processes,such as dynamic recovery and boundary migration.Unlike the ultrafine lamella formed under the high-Z condition,a variety of microstructures having equiaxed morphologies with fine to coarse grain sizes(>1μm)were realized with decreasing Z.The significance of the grain subdivision and the thermally activated phenomena on the formation of various microstructures under different deformation conditions is discussed.展开更多
The third-order optical nonlinearities and responses of poly（methyl methacrylate） （PMMA） coating films containing J-like aggregates of a thiadicarbocyanine dye, 3,3＇-diethyl-2,2＇-thiadicarbocyanine iodide （DTDC...The third-order optical nonlinearities and responses of poly（methyl methacrylate） （PMMA） coating films containing J-like aggregates of a thiadicarbocyanine dye, 3,3＇-diethyl-2,2＇-thiadicarbocyanine iodide （DTDC1）, are measured by degenerate four-wave mixing （DFWM） technique under resonant conditions. The temporal profiles of the DFWM signal of PMMA coating films containing J-like aggregates of DTDC1 are found to consist of three components： i.e., the coherent instantaneous nonlinear response （electronic response） and the two slow responses uqth decay time constants of about 0.8ps and about 7.0ps. The electronic component of the effective third-order nonlinear susceptibility, χc^（3）, of one of the present films is as high as about 2.1×10^-8 esu, and the figure of merit of third-order nonlinearity F （F=χ^（3）/α） is evaluated to be about 1.9 ×10^-13 esu cm at 850nm.展开更多
Third-order optical nonlinearities of two squarylium dyes with benzothiazole donor groups(BSQ1 and BSQ2)in chloroform solution are measured by a picosecond Z-scan technique at 532 nm.It is found that the two compounds...Third-order optical nonlinearities of two squarylium dyes with benzothiazole donor groups(BSQ1 and BSQ2)in chloroform solution are measured by a picosecond Z-scan technique at 532 nm.It is found that the two compounds show the saturation absorption and nonlinear self-focus refraction effect.The molecular second hyperpolarizabilities are calculated to be 7.46×10^(−31) esu and 5.01×10^(−30) esu for BSQ1 and BSQ2,respectively.The large optical nonlinearities of squarylium dyes can be attributed to their rigid and intramolecular charge transfer structure.The difference inγvalues is attributed to the chloro group of benzene rings of BSQ2 and the one−photon resonance effect.It is found that the third-order nonlinear susceptibilities of two squarylium dyes are mainly determined by the real parts ofχ(3),and the large optical nonlinearities of studied squarylium dyes can be attributed to the nonlinear refraction.展开更多
The development of effective synthetic routes is important to manifest proper nature of specific materials.In-situ electrochemical functionalization possesses great advantages over conventional routes,especially facil...The development of effective synthetic routes is important to manifest proper nature of specific materials.In-situ electrochemical functionalization possesses great advantages over conventional routes,especially facile way and leading to reaching elaborate sites of functional group.Here,we demonstrate the preparation of functionalized carbons by in-situ electrochemical reduction in an argon atmosphere for application in low-cost,environmentally benign,and high-performance oxygen-electrodes for non-aqueous Li-O2 batteries.A Li-O2 battery with functionalized carbon shows a high discharge capacity(100 times that of pristine carbon),high power and cycling stability.The outstanding performance is attributed to the high O2 affinity of the functionalized carbon surface that facilitates the formation of soluble and diffusible superoxide intermediates by the reduction of the remaining O2 competing with surface growth for Li2O2 formation.展开更多
Emerging machine learning(ML)approaches have been adopted in various material systems to predict novel properties with the assistance of the corresponding large datasets.For new materials,however,collecting sufficient...Emerging machine learning(ML)approaches have been adopted in various material systems to predict novel properties with the assistance of the corresponding large datasets.For new materials,however,collecting sufficient data points for model training is not feasible,which is the case for gold nanoparticle/polymer hybrid films.In this study,an ML approach coupled with finite element modeling was proposed for predicting the optical and photothermal properties of gold nanoparticle/polymer hybrid films.Experimental datasets of the optical and photothermal properties were built using results from the literature.Then,finite element analyses were conducted to generate synthetic data to satisfy the quality and quantity of the data required for training models.Correlation analysis and model training were performed using the datasets with and without synthetic data to evaluate their effects on predicting the performance of the ML models.The relative importance of features to targets(properties)was evaluated by correlation analysis.ML models with high accuracy were obtained by training various models from conventional to newly developed algorithms.Advantages,weaknesses,and improvement of the synthetic data addition were discussed.The proposed workflow and framework offer reliable prediction of optical and photothermal properties over different combinations of gold nanoparticles and polymer matrices,which can be extended to include more features related to processing parameters and microstructures.展开更多
Ag2S‐graphene/TiO2 composites were synthesized by a facile sonochemical method.The products were characterized by X‐ray diffraction,scanning electron microscopy,energy dispersive X‐ray spectroscopy,transmission ele...Ag2S‐graphene/TiO2 composites were synthesized by a facile sonochemical method.The products were characterized by X‐ray diffraction,scanning electron microscopy,energy dispersive X‐ray spectroscopy,transmission electron microscopy,and UV‐Vis diffuse reflectance spectrophotometry.During the synthesis reaction,the reduction of graphene oxide and loading of Ag2S and TiO2 particles were achieved.The Ag2S‐graphene/TiO2 composites possessed a large adsorption capacity for dyes,an extended light absorption range,and efficient charge separation properties.Hence,in the photodegradation of rhodamine B,a significant enhancement in the reaction rate was observed with the Ag2S‐graphene/TiO2 composites as compared to pure TiO2.The generation of reactive oxygen species was detected by the oxidation of 1,5‐diphenyl carbazide to 1,5‐diphenyl carbazone.The high activity was attributed to the synergetic effects of high charge mobility and the red shift in the absorption edge of the Ag2S‐graphene/TiO2 composites.展开更多
A cyanine dye, 2-[7-（1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene）-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide （NK-125）, is doped in 4-cyano-4＇-pentylbiphenyl （5 CB）, and the mixture is sandwiched ...A cyanine dye, 2-[7-（1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene）-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide （NK-125）, is doped in 4-cyano-4＇-pentylbiphenyl （5 CB）, and the mixture is sandwiched between two pieces of rubbed glass plates. The third-order nonlinear optical properties of the oriented NK-125-SCB layers are measured by the resonant femtosecond degenerate four-wave mixing （DFWM） technique at 760 nm. The third-order nonlinear optical susceptibility of one of the present samples is 5.5×10^-8 esu. The slow DFWM response of the NK-125-SCB layers due to a population grating is accelerated by the increasing laser power because of amplified spontaneous emission （ASE）. On the other hand, we do not observe a similar phenomenon for NK-125- polyethylene glycol （PEG-400）. Oriented NK-125 molecules in nematic liquid crystals must have very high ASE efficiency. Hence the population grating in a DFWM signal disappears within about 4 ps. It is expected that NK-125-SCB can be used as a material for very fast all-optical switching.展开更多
Wastes can be defined as unwanted materials that are dumped away from several sources.It can be a by-product of home,agricultural,industrial,commercial,mining,and other ventures,sources,or activities.Nowadays such was...Wastes can be defined as unwanted materials that are dumped away from several sources.It can be a by-product of home,agricultural,industrial,commercial,mining,and other ventures,sources,or activities.Nowadays such waste materials are not just waste;they are becoming the source of wealth and health.A substantial volume of organic waste,around 1.3 billion tons per year,is identified as a possible source of feedstock for biobased goods.Waste materials are being used for the development of various useful products,such as bioenergy,biomaterials,biotechnology,and so on.Wastes are valuable resources for health and wealth creation,with an emphasis on resources recovered from environmental and agro-food wastes applying via biotechnology.This review focuses on biotechnological applications in waste valorizations and examines the health and economic effects of obtaining resources from agro-food and environmental wastes.According to the quantitative findings,producing biogas from agro-food sector waste can provide between 80 and 150 m^(3) of biogas for every ton of fresh organic waste,which result in significant energy savings and greenhouse gas mitigation.Furthermore,it has been suggested that converting just 10%of the world’s food waste may result in financial gains of over 100 billion USD in addition to reducing the health hazards related to trash disposal.By demonstrating that the valorization not only generates financial gains through the development of bioplastics and biofertilizers but also improves health outcomes by reducing pollution and improving food safety,the paper highlights the double advantages of waste recovery.Besides,it emphasizes the application of biotechnological methods,showcasing innovative and scientific approaches to resource recovery in which the reviewed findings will be relevant for industry stakeholders and policymakers.展开更多
With advances in artificial intelligence(AI)-based algorithms,gesture recognition accuracy from sEMG signals has continued to increase.Spatiotemporal multichannel-sEMG signals substantially increase the quantity and r...With advances in artificial intelligence(AI)-based algorithms,gesture recognition accuracy from sEMG signals has continued to increase.Spatiotemporal multichannel-sEMG signals substantially increase the quantity and reliability of the data for any type of study.Here,we report an array of bipolar stretchable sEMG electrodes with a self-attention-based graph neural network to recognize gestures with high accuracy.The array is designed to spatially cover the skeletal muscles to acquire the regional sampling data of EMG activity from 18 different gestures.The system can differentiate individual static and dynamic gestures with~97%accuracy when training a single trial per gesture.Moreover,a sticky patchwork of holes adhered to an array sensor enables skin-like attributes such as stretchability and water vapor permeability and aids in delivering stable EMG signals.In addition,the recognition accuracy(~95%)remained unchanged even after long-term testing for over 72 h and being reused more than 10 times.展开更多
Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive ra...Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive range for biomedical application.However,a deep understanding of the role of the C-N configuration in the CDs’properties is still challenging and thoughtprovoking owing to their complex structure.Here,an underlying pyrrolic-N concentration and position effect on the pyrrolic-N-rich CDs’absorption was comprehensively elucidated based on the integrated experimental and computational studies.The assynthesized pyrrolic-N-rich CDs exhibit a first NIR window absorption centered at 650 nm with high photothermal conversion.Pyrrolic-N concentrations from 1.4%to 11.3%and positions(edge and mid-site)were systematically investigated.A mid-site pyrrolic-N was subsequently generated after the pyrrolic-N concentration more than 10%.Edge-site pyrrolic-N induces a frontier orbital hybridization,reducing bandgap energy,while mid-site pyrrolic-N plays a critical role in inducing a first NIR window absorption owing to their high charge transfer.Also,pyrrolic-N-rich CDs inherit a bowl-like topological feature,elevating the CDs’layer thickness as much as 0.71 nm.This study shed light on the design and optimization of pyrrolic-N on CDs for the first NIR window responsive materials in any biomedical application.展开更多
Wind power is crucial for achieving carbon neutrality,but its output can vary due to local wind conditions.The spatio-temporal behavior of wind power generation connected to the power grid can have a significant impac...Wind power is crucial for achieving carbon neutrality,but its output can vary due to local wind conditions.The spatio-temporal behavior of wind power generation connected to the power grid can have a significant impact on system operations.To assess this impact,the use of long-term reanalysis results of wind data based on a numerical weather prediction(NWP)model is considered valid.However,in Japan,the behavior of on-shore wind power generation is influenced by diverse topographical and meteorological features(TMFs)of the installation site,making it challenging to assess possible operational impacts based solely on power curve-based estimates using a popular conversion equation.In this study,a nonparametric machine learning-based post-processing model that learns the statistical relationship between the TMFs at the target location and the actual wind farm(WF)output was developed to represent the expected per-unit output at each location.Focusing on historical reconstruction results and using this post-processing model to reproduce the real-world WF output behavior created a set of expected wind power generation profiles.The dataset includes hourly long term(1958-2012)wind power generation profiles expected under the WF installation assumptions at various on-shore locations in Japan with a 5 km spatial resolution and is expected to contribute to an accurate understanding of the impact of spatio-temporal wind power behavior.The dataset is publicly accessible at https://doi.org/10.5281/zenodo.11496867(Fujimotoet al.,2024).展开更多
The microstructure is a critical factor governing the functionality of ceramic materials.Meanwhile,microstructural analysis of electron microscopy images of polycrystalline ceramics,which are geometrically complex and...The microstructure is a critical factor governing the functionality of ceramic materials.Meanwhile,microstructural analysis of electron microscopy images of polycrystalline ceramics,which are geometrically complex and composed of countless crystal grains with porosity and secondary phases,has generally been performed manually by human experts.Objective pixel-based analysis(semantic segmentation)with high accuracy is a simple but critical step for quantifying microstructures.In this study,we apply neural network-based semantic segmentation to secondary electron images of polycrystalline ceramics obtained by three-dimensional(3D)imaging.The deeplearning-based models(e.g.,fully convolutional network and U-Net)by employing a dataset based on a 3D scanning electron microscopy with a focused ion beam is found to be able to recognize defect structures characteristic of polycrystalline materials in some cases due to artifacts in electron microscopy imaging.Owing to the training images with improved depth accuracy,the accuracy evaluation function,intersection over union(IoU)values,reaches 94.6%for U-Net.These IoU values are among the highest for complex ceramics,where the 3D spatial distribution of phases is difficult to locate from a 2D image.Moreover,we employ the learned model to successfully reconstruct a 3D microstructure consisting of giga-scale voxel data in a few minutes.The resolution of a single voxel is 20 nm,which is higher than that obtained using a typical X-ray computed tomography.These results suggest that deep learning with datasets that learn depth information is essential in 3D microstructural quantifying polycrystalline ceramic materials.Additionally,developing improved segmentation models and datasets will pave the way for data assimilation into operando analysis and numerical simulations of in situ microstructures obtained experimentally and for application to process informatics.展开更多
基金financially supported by the Fundamental Research Program of the Korea Institute of Materials Science(No.PNKA330)
文摘Although hot-rolled La(Fe,Co,Si)13-based alloys are promising magnetocaloric materials for solidstate cooling with near-net shaping capabilities,their underlying hot deformation mechanisms remain largely unexplored.In this study,a comprehensive and systematic investigation was conducted,by encompassing the analysis of hot deformation mechanisms,along with the microstructure evolution and magnetoc aloric properties of hot-rolled La-Fe-Co-Si alloy.The La_(1.05)Fe_(11.2)Co_(0.7)Si_(1.38)alloy was examined using multiscale mechanical analysis to assess the effects of temperature.A series of macroscale hot compression and microscale nanoindentation tests were performed to access global and local mechanical properties,including variations in hardness and indentation modulus of the primaryα-Fe and secondary 1:1:1 phases up to 800℃.A significant decrease in hardness and elastic recovery of the secondary phase was observed between 600and 800℃,above half of its melting point(1113℃),suggesting pronounced flow softening in both theα-Fe and 1:1:1 phases.Additionally,a novel multi-step annealing process was introduced for hot-rolled La-Fe-Co-Si alloys,involving partial transient liquid-phase diffusion in the 1:1:1 phase to address deformation-induced defects,such as residualα-Fe and lattice distortions in the 1:13 phase,which have not been previously reported.As a result,a primary La(Fe,Co,Si)13phase with a volume fraction of97.5%was achieved after multi-step annealing,compared to 87.5%using conventional annealing.Correspondingly,the magnetocaloric properties were restored,with the Curie temperature(TC)recovering from 276 to 268 K and the maximum magnetic entropy change(ΔSM)increasing from 7.56 to 8.67 J kg^(-1)K^(-1)under a 2 T magnetic field.
文摘ECO-Al alloys are introduced as a game-changer for the aluminum industry and it is of utmost importance to determine the role of alloying elements in their processing characteristics.In this study,the effects of Cr on the hot deformation behavior of newly-developed ECO-7175 alloy were investigated.ECO-7175 samples with and without Cr were hot-compressed using a Gleeble simulator(temperature range of 350−500℃ and strain rates of 0.001−1 s^(−1)).The results were used to study the constitutive equations,the processing maps,and the microstructural evolution of the alloys.In Cr-containing alloy,the analysis of the deformation activation energy reveals that the rate-controlling mechanisms of the deformation change gradually from self-diffusion of Al(or diffusion of Mg in Al)to diffusion of Cr in Al by decreasing the Zener−Hollomon parameter.The analysis of the processing maps of Cr-containing alloy shows that the dynamic recrystallization(DRX)zone is limited to the deformation at high temperatures and low strain rates and expands with increasing applied strain.On the other hand,it is found that the self-diffusion of Al(or Mg in Al)is the only rate-controlling mechanism during hot deformation of Cr-free alloy in all processing conditions and its DRX zone is independent of the plastic strain.
基金supported by a Grant from the Fundamental R&D Program(10067694)funded by the Ministry of Trade,Industry and Energy,Korea。
文摘Nb tubes were fabricated through hydrostatic extrusion at extrusion ratios of 3.1 and 6.1 at ambient temperature,and then their microstructure,texture,and Vickers hardness were investigated based on electron back-scattered diffraction(EBSD)data.The fraction of low-angle boundaries(LABs)largely decreased with a sharp decrease in mean grain sizes after hydrostatic extrusion and was not proportional to extrusion ratios,assuming that mixed-asymmetrical junctions forming LABs dissociate at high extrusion ratios from the external stress(>981 MPa)with thermal activation by the generated heat.The correlation between grain size and Vickers hardness followed the Hall−Petch relationship despite the texture gradient of theá111ñcyclic fiber textural microstructure at low extrusion ratios and theá100ñtrue fiber textural microstructure at high extrusion ratios.The increase in hydrostatic pressure on the Nb tubes contributed to texture evolution in terms of extrusion ratios due to the difference between{110}<111>and{112}<111>components based on EBSD data.
文摘The third-order optical nonlinearities and responses of a squarylium dye, 2,4-di-3-guaiazulenyl-1,3-dihydroxycyclobutenediylium dihydroxide, in tetrahydrofuran （THF） solution and in polystyrene （PS） coating films are measured by the femtosecond degenerate four-wave mixing technique under resonant conditions. The molecular hyperpolarizability γ of the squarylium dye in the THF solution is determined to be 3.0 × 10^-29 esu at 764 nm, and its electronic component γe is determined to be 1.1 × 10^-29 esu. The third-order nonlinear susceptibility X^（3） of one of the present PS coating films containing the squarylium dye is as high as 3.1 × 10^-8 esu at 80Ohm, and its electronic component Xe^（3） is 1.3 × 10^-8 esu.
基金supported by the National Key R&D Program of China (2018YFE0208500)the Japan Science and Technology Agency (JST) Mirai program (JPMJMI17EA)。
文摘As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].
文摘A squarylium dye is dissolved in 4-cyano-4＇-pentylbiphenyl （SCB） and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB layers exhibit high anisotropy. The third-order nonlinear optical responses and susceptibilities X^（3）e of squarylium dye in 5CB are measured with light polarizations parallel and perpendicular to the orientational direction by the resonant femtosecond degenerate four-wave mixing （DFWM） technique. Temporal profiles of the DFWM signal of the oriented squarylium dye-5CB layers with light polarizations parallel and perpendicular to the orientational direction are measured with a time resolution of 0.3ps （FWHM）, and are found to consist of two components, i.e., the coherent instantaneous nonlinear response and slow response due to the formation of excited molecules. A high anisotropic ratio of x^（3）e, 10.8 ：k 1.2, is observed for the oriented layers.
基金supported by 2008 Research Grant from Kangwon National University,Korea
文摘Surface functionalization of suspended single-walled carbon nanotubes(SWNTs) using metal(Au) nanoparticles(NPs) is reported.SWNTs are grown on three-dimensionally patterned substrates by thermal chemical vapor deposition and successfully functionalized with Au NPs.Ethylendiamine is mainly used to functionalize SWNTs surface with amino groups before introducing Au NPs.From Raman scattering spectroscopy of the Au-functionalized suspended SWNTs,enhanced Raman scattering properties are obtained.The results suggest that the attached Au NPs may contribute to the enhancement of resonant phenomena.By measuring the electric properties after each functionalization process,it is found that Au NPs act as electron acceptor to the amine functionalized SWNTs.
基金supported by the Korea Evaluation Institute of Industrial Technology(KEIT)grant funded by the Korea Ministry of Trade Industry&Energy(MOTIE)[10062871,Development of high efficiention exchange materials and modules for preparing UPW for semi-conducting industry applications].
文摘Regeneration of pure water is an important issue not only for the healthy life but also for the fine control of precise processes in various industries.One important issue in ultrahigh purified water is to reduce the amount of total organic carbon(TOC).Herein,we introduce a new approach to reduce the TOC using the surface silanized nanoparticles,in which the magnetic nanoparticles(mNPs)are silanized and then complexed with ion exchange resin(IER)beads.The Fe3O4 mNPs are surface modified by using high concentrated vinyltrimethoxysilane(VTMS)and then adhered on the surface of IER beads.The surface modified mNPs have a thick-shell of polysiloxane layer varying from 5 to 22 nm depending on the amount of VTMS used,which leads the significant increase of specific surface area.The IER beads embedding VTMS-silanized mNPs achieves about 7μg/L of the TOC level in ultrapure water system,which is two orders less than 228μg/L of the feeding water and one order less than 96μg/L from the system using pristine IER beads.This result is mainly attributed to the polysiloxane layer forming broccoli-like surface structure and some part by the vinyl group of VTMS exposed to the amines in the water.
基金financially supported by the Grant-in-Aid for Scientific Research(S)(No.15H05767)the Grant-in-Aid for Scientific Research on Innovative Area,“Bulk Nanostructured Metals”(Area No.2201)+1 种基金the Elements Strategy Initiative for Structural Materials(ESISM,No.JPMXP0112101000)JST CREST(No.JPMJCR1994)all through the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan.
文摘Single-phase bcc-ferrite in an interstitial free(IF)steel was deformed to different strains in a wide range from low to high strains(ε=1–7)by torsion under different Zener-Hollomon(Z)conditions.The specimens were rapidly quenched after the torsion to preserve microstructures formed under different deformation conditions.The results showed that during high-Z(low-temperature)deformation,grains were subdivided by geometrically necessary boundaries(GNBs)via the grain subdivision mechanism.Deformation to high strains(ε>5)led to the ultrafine lamellar structures(with grain sizes<1μm)mainly composed of GNBs having high misorientation angles.Decreasing Z with increasing temperature and/or decreasing strain rate accelerated thermally activated processes,such as dynamic recovery and boundary migration.Unlike the ultrafine lamella formed under the high-Z condition,a variety of microstructures having equiaxed morphologies with fine to coarse grain sizes(>1μm)were realized with decreasing Z.The significance of the grain subdivision and the thermally activated phenomena on the formation of various microstructures under different deformation conditions is discussed.
文摘The third-order optical nonlinearities and responses of poly（methyl methacrylate） （PMMA） coating films containing J-like aggregates of a thiadicarbocyanine dye, 3,3＇-diethyl-2,2＇-thiadicarbocyanine iodide （DTDC1）, are measured by degenerate four-wave mixing （DFWM） technique under resonant conditions. The temporal profiles of the DFWM signal of PMMA coating films containing J-like aggregates of DTDC1 are found to consist of three components： i.e., the coherent instantaneous nonlinear response （electronic response） and the two slow responses uqth decay time constants of about 0.8ps and about 7.0ps. The electronic component of the effective third-order nonlinear susceptibility, χc^（3）, of one of the present films is as high as about 2.1×10^-8 esu, and the figure of merit of third-order nonlinearity F （F=χ^（3）/α） is evaluated to be about 1.9 ×10^-13 esu cm at 850nm.
基金by the National Natural Science General Foundation of China under Grant Nos 20572059 and 20502013the National Key Fundamental Research Program under Grant No 2007CB808000.
文摘Third-order optical nonlinearities of two squarylium dyes with benzothiazole donor groups(BSQ1 and BSQ2)in chloroform solution are measured by a picosecond Z-scan technique at 532 nm.It is found that the two compounds show the saturation absorption and nonlinear self-focus refraction effect.The molecular second hyperpolarizabilities are calculated to be 7.46×10^(−31) esu and 5.01×10^(−30) esu for BSQ1 and BSQ2,respectively.The large optical nonlinearities of squarylium dyes can be attributed to their rigid and intramolecular charge transfer structure.The difference inγvalues is attributed to the chloro group of benzene rings of BSQ2 and the one−photon resonance effect.It is found that the third-order nonlinear susceptibilities of two squarylium dyes are mainly determined by the real parts ofχ(3),and the large optical nonlinearities of studied squarylium dyes can be attributed to the nonlinear refraction.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2016R1A6A3A04013238)。
文摘The development of effective synthetic routes is important to manifest proper nature of specific materials.In-situ electrochemical functionalization possesses great advantages over conventional routes,especially facile way and leading to reaching elaborate sites of functional group.Here,we demonstrate the preparation of functionalized carbons by in-situ electrochemical reduction in an argon atmosphere for application in low-cost,environmentally benign,and high-performance oxygen-electrodes for non-aqueous Li-O2 batteries.A Li-O2 battery with functionalized carbon shows a high discharge capacity(100 times that of pristine carbon),high power and cycling stability.The outstanding performance is attributed to the high O2 affinity of the functionalized carbon surface that facilitates the formation of soluble and diffusible superoxide intermediates by the reduction of the remaining O2 competing with surface growth for Li2O2 formation.
基金financial support from National Science Foundation under grant(No.CBET-2024546)the School of Engineering at University of Alabama at Birmingham.
文摘Emerging machine learning(ML)approaches have been adopted in various material systems to predict novel properties with the assistance of the corresponding large datasets.For new materials,however,collecting sufficient data points for model training is not feasible,which is the case for gold nanoparticle/polymer hybrid films.In this study,an ML approach coupled with finite element modeling was proposed for predicting the optical and photothermal properties of gold nanoparticle/polymer hybrid films.Experimental datasets of the optical and photothermal properties were built using results from the literature.Then,finite element analyses were conducted to generate synthetic data to satisfy the quality and quantity of the data required for training models.Correlation analysis and model training were performed using the datasets with and without synthetic data to evaluate their effects on predicting the performance of the ML models.The relative importance of features to targets(properties)was evaluated by correlation analysis.ML models with high accuracy were obtained by training various models from conventional to newly developed algorithms.Advantages,weaknesses,and improvement of the synthetic data addition were discussed.The proposed workflow and framework offer reliable prediction of optical and photothermal properties over different combinations of gold nanoparticles and polymer matrices,which can be extended to include more features related to processing parameters and microstructures.
基金supported by Research Foundation from Hanseo University in 2012the staff at the University for the financial support
文摘Ag2S‐graphene/TiO2 composites were synthesized by a facile sonochemical method.The products were characterized by X‐ray diffraction,scanning electron microscopy,energy dispersive X‐ray spectroscopy,transmission electron microscopy,and UV‐Vis diffuse reflectance spectrophotometry.During the synthesis reaction,the reduction of graphene oxide and loading of Ag2S and TiO2 particles were achieved.The Ag2S‐graphene/TiO2 composites possessed a large adsorption capacity for dyes,an extended light absorption range,and efficient charge separation properties.Hence,in the photodegradation of rhodamine B,a significant enhancement in the reaction rate was observed with the Ag2S‐graphene/TiO2 composites as compared to pure TiO2.The generation of reactive oxygen species was detected by the oxidation of 1,5‐diphenyl carbazide to 1,5‐diphenyl carbazone.The high activity was attributed to the synergetic effects of high charge mobility and the red shift in the absorption edge of the Ag2S‐graphene/TiO2 composites.
文摘A cyanine dye, 2-[7-（1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene）-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide （NK-125）, is doped in 4-cyano-4＇-pentylbiphenyl （5 CB）, and the mixture is sandwiched between two pieces of rubbed glass plates. The third-order nonlinear optical properties of the oriented NK-125-SCB layers are measured by the resonant femtosecond degenerate four-wave mixing （DFWM） technique at 760 nm. The third-order nonlinear optical susceptibility of one of the present samples is 5.5×10^-8 esu. The slow DFWM response of the NK-125-SCB layers due to a population grating is accelerated by the increasing laser power because of amplified spontaneous emission （ASE）. On the other hand, we do not observe a similar phenomenon for NK-125- polyethylene glycol （PEG-400）. Oriented NK-125 molecules in nematic liquid crystals must have very high ASE efficiency. Hence the population grating in a DFWM signal disappears within about 4 ps. It is expected that NK-125-SCB can be used as a material for very fast all-optical switching.
文摘Wastes can be defined as unwanted materials that are dumped away from several sources.It can be a by-product of home,agricultural,industrial,commercial,mining,and other ventures,sources,or activities.Nowadays such waste materials are not just waste;they are becoming the source of wealth and health.A substantial volume of organic waste,around 1.3 billion tons per year,is identified as a possible source of feedstock for biobased goods.Waste materials are being used for the development of various useful products,such as bioenergy,biomaterials,biotechnology,and so on.Wastes are valuable resources for health and wealth creation,with an emphasis on resources recovered from environmental and agro-food wastes applying via biotechnology.This review focuses on biotechnological applications in waste valorizations and examines the health and economic effects of obtaining resources from agro-food and environmental wastes.According to the quantitative findings,producing biogas from agro-food sector waste can provide between 80 and 150 m^(3) of biogas for every ton of fresh organic waste,which result in significant energy savings and greenhouse gas mitigation.Furthermore,it has been suggested that converting just 10%of the world’s food waste may result in financial gains of over 100 billion USD in addition to reducing the health hazards related to trash disposal.By demonstrating that the valorization not only generates financial gains through the development of bioplastics and biofertilizers but also improves health outcomes by reducing pollution and improving food safety,the paper highlights the double advantages of waste recovery.Besides,it emphasizes the application of biotechnological methods,showcasing innovative and scientific approaches to resource recovery in which the reviewed findings will be relevant for industry stakeholders and policymakers.
基金the National Research Foundation of Korea(NRF-2022M3D1A2083618,2021R1A2B5B02002167,2021R1I1A1A01060078,and 2021R1C1C1005407)supported by the SKKU Research Fellowship Program of the Sungkyunkwan University and the Institute of Information&Communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(No.2019-0-00421,Artificial Intelligence Graduate School Program(Sungkyunkwan University))supported by the SafeD Inc.and BECS Inc.
文摘With advances in artificial intelligence(AI)-based algorithms,gesture recognition accuracy from sEMG signals has continued to increase.Spatiotemporal multichannel-sEMG signals substantially increase the quantity and reliability of the data for any type of study.Here,we report an array of bipolar stretchable sEMG electrodes with a self-attention-based graph neural network to recognize gestures with high accuracy.The array is designed to spatially cover the skeletal muscles to acquire the regional sampling data of EMG activity from 18 different gestures.The system can differentiate individual static and dynamic gestures with~97%accuracy when training a single trial per gesture.Moreover,a sticky patchwork of holes adhered to an array sensor enables skin-like attributes such as stretchability and water vapor permeability and aids in delivering stable EMG signals.In addition,the recognition accuracy(~95%)remained unchanged even after long-term testing for over 72 h and being reused more than 10 times.
基金This work was fully supported by the Indonesian Endowment Fund for Education and the Indonesian Science Fund through the International Collaboration RISPRO Funding Program(No.RISPRO/KI/B1/KOM/11/4542/2/2020).
文摘Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive range for biomedical application.However,a deep understanding of the role of the C-N configuration in the CDs’properties is still challenging and thoughtprovoking owing to their complex structure.Here,an underlying pyrrolic-N concentration and position effect on the pyrrolic-N-rich CDs’absorption was comprehensively elucidated based on the integrated experimental and computational studies.The assynthesized pyrrolic-N-rich CDs exhibit a first NIR window absorption centered at 650 nm with high photothermal conversion.Pyrrolic-N concentrations from 1.4%to 11.3%and positions(edge and mid-site)were systematically investigated.A mid-site pyrrolic-N was subsequently generated after the pyrrolic-N concentration more than 10%.Edge-site pyrrolic-N induces a frontier orbital hybridization,reducing bandgap energy,while mid-site pyrrolic-N plays a critical role in inducing a first NIR window absorption owing to their high charge transfer.Also,pyrrolic-N-rich CDs inherit a bowl-like topological feature,elevating the CDs’layer thickness as much as 0.71 nm.This study shed light on the design and optimization of pyrrolic-N on CDs for the first NIR window responsive materials in any biomedical application.
文摘Wind power is crucial for achieving carbon neutrality,but its output can vary due to local wind conditions.The spatio-temporal behavior of wind power generation connected to the power grid can have a significant impact on system operations.To assess this impact,the use of long-term reanalysis results of wind data based on a numerical weather prediction(NWP)model is considered valid.However,in Japan,the behavior of on-shore wind power generation is influenced by diverse topographical and meteorological features(TMFs)of the installation site,making it challenging to assess possible operational impacts based solely on power curve-based estimates using a popular conversion equation.In this study,a nonparametric machine learning-based post-processing model that learns the statistical relationship between the TMFs at the target location and the actual wind farm(WF)output was developed to represent the expected per-unit output at each location.Focusing on historical reconstruction results and using this post-processing model to reproduce the real-world WF output behavior created a set of expected wind power generation profiles.The dataset includes hourly long term(1958-2012)wind power generation profiles expected under the WF installation assumptions at various on-shore locations in Japan with a 5 km spatial resolution and is expected to contribute to an accurate understanding of the impact of spatio-temporal wind power behavior.The dataset is publicly accessible at https://doi.org/10.5281/zenodo.11496867(Fujimotoet al.,2024).
基金supported by JST CREST(JPMJCR18J4),JSPS KAKENHI(JP21H01615 and JP18H01699)Nanotechnology Platform(A-18-TU-0037)of the MEXT,Japan.
文摘The microstructure is a critical factor governing the functionality of ceramic materials.Meanwhile,microstructural analysis of electron microscopy images of polycrystalline ceramics,which are geometrically complex and composed of countless crystal grains with porosity and secondary phases,has generally been performed manually by human experts.Objective pixel-based analysis(semantic segmentation)with high accuracy is a simple but critical step for quantifying microstructures.In this study,we apply neural network-based semantic segmentation to secondary electron images of polycrystalline ceramics obtained by three-dimensional(3D)imaging.The deeplearning-based models(e.g.,fully convolutional network and U-Net)by employing a dataset based on a 3D scanning electron microscopy with a focused ion beam is found to be able to recognize defect structures characteristic of polycrystalline materials in some cases due to artifacts in electron microscopy imaging.Owing to the training images with improved depth accuracy,the accuracy evaluation function,intersection over union(IoU)values,reaches 94.6%for U-Net.These IoU values are among the highest for complex ceramics,where the 3D spatial distribution of phases is difficult to locate from a 2D image.Moreover,we employ the learned model to successfully reconstruct a 3D microstructure consisting of giga-scale voxel data in a few minutes.The resolution of a single voxel is 20 nm,which is higher than that obtained using a typical X-ray computed tomography.These results suggest that deep learning with datasets that learn depth information is essential in 3D microstructural quantifying polycrystalline ceramic materials.Additionally,developing improved segmentation models and datasets will pave the way for data assimilation into operando analysis and numerical simulations of in situ microstructures obtained experimentally and for application to process informatics.
