Neuromorphic computing devices leveraging HfO_(2) and ZrO_(2) materials have recently garnered significant attention due to their potential for brain-inspired computing systems.In this study,we present a novel trilaye...Neuromorphic computing devices leveraging HfO_(2) and ZrO_(2) materials have recently garnered significant attention due to their potential for brain-inspired computing systems.In this study,we present a novel trilayer Pt/HfO_(2)/ZrO_(2-x)/HfO_(2)/TiN memristor,engineered with a ZrO_(2-x) oxygen vacancy reservoir(OVR)layer fabricated via radio frequency(RF)sputtering under controlled oxygen ambient.The incorporation of the ZrO_(2-x) OVR layer enables enhanced resistive switching characteristics,including a high ON/OFF ratio(∼8000),excellent uniformity,robust data retention(>105 s),and multilevel storage capabilities.Furthermore,the memristor demonstrates superior synaptic plasticity with linear long-term potentiation(LTP)and depression(LTD),achieving low non-linearity values of 1.36(LTP)and 0.66(LTD),and a recognition accuracy of 95.3%in an MNIST dataset simulation.The unique properties of the ZrO_(2-x) layer,particularly its ability to act as a dynamic oxygen vacancy reservoir,significantly enhance synaptic performance by stabilizing oxygen vacancy migration.These findings establish the OVR-trilayer memristor as a promising candidate for future neuromorphic computing and high-performance memory applications.展开更多
Artificial sensory systems(ASS)are pivotal to next-generation extended reality technologies,now evolving into flexible platforms for comfortable wear and immersive user experiences,while ensuring high performance and ...Artificial sensory systems(ASS)are pivotal to next-generation extended reality technologies,now evolving into flexible platforms for comfortable wear and immersive user experiences,while ensuring high performance and operational reliability.To address these demands,metal-based nanoparticles(NPs),such as noble metal,oxide,and multi-elemental NPs,have been extensively incorporated into functional materials of sensory and synaptic devices due to their tunable optical,electrical,and chemical properties,enhancing sensory precision,stability,and environmental adaptability.However,traditional NP fabrication methods often involve complex processing,residual contaminants,and scalability issues,limiting their effectiveness in ASS applications.State-of-the-art laser ablation in liquids(LAL)presents a promising alternative,offering scalable production of surfactant-free NPs with customizable physicochemical properties,though their application in electronics remains underexplored.This review delves into the transformative potential of LAL-fabricated NPs in ASS,covering the fundamental mechanisms of LAL,the role of process parameters,the derivative strategies for size modulation,the diversity of metal-based NPs,their applications in sensory and synaptic devices,and the challenges and perspectives for meeting industrial standards.Bridging the gap between LAL and ASS is poised to revolutionize both industrial manufacturing and academic research by offering scalable solutions to overcome intrinsic tradeoffs between flexibility and performance,fostering innovations in human-centric,immersive electronics.展开更多
The increasing importance of high-purity isopropyl alcohol(IPA)in semiconductor processing technology has led to a higher demand for technologies capable of detecting impurities in IPA.Although accurate and various im...The increasing importance of high-purity isopropyl alcohol(IPA)in semiconductor processing technology has led to a higher demand for technologies capable of detecting impurities in IPA.Although accurate and various impurity detection technologies have been developed,most of them have limitations in real-time and repeatable detection of impurities.Herein,for the first time,surface plasmon resonance(SPR)sensor was developed utilizing graphene transferred Au film(Au/graphene)to detect sub-ppm levels of 2,4-dinitrophenol(2,4-DNP)dissolved in IPA and this sensor demonstrates the ability to detect 2,4-DNP in real-time with great reversibility.The adsorption of 2,4-DNP to graphene is found to be stronger than that for Au film because of noncovalent graphene p–p stacking interaction,and the effect of graphene is demonstrated through density function theory(DFT)calculations and enhancement in sensing performance of Au/graphene sensor.Additionally,the presence of noncovalent p–p stacking interaction between 2,4-DNP and graphene has been demonstrated by confirming the p-doping effect of graphene-based solution field-effect transistor measurements and consecutive Raman spectra analysis.This study offers experimental and theoretical insights into the adsorption kinetics of 2,4-DNP dissolved in IPA and provides promising perspectives for real-time sensing technology utilizing label-free graphene to detect impurities in high-purity cleaning agents.展开更多
Governments worldwide have implemented non-pharmaceutical interventions(NPIs)to control the spread of coronavirus disease 2019(COVID-19),and it is crucial to accurately assess the effectiveness of such measures.Many s...Governments worldwide have implemented non-pharmaceutical interventions(NPIs)to control the spread of coronavirus disease 2019(COVID-19),and it is crucial to accurately assess the effectiveness of such measures.Many studies have quantified the risk of infection transmission and used simulations to compare the risk before and after the implementation of NPIs to judge policies’effectiveness.However,the choice of metric used to quantify the risk can lead to different conclusions regarding the effectiveness of a policy.In this study,we analyze the correlation between different transmission-risk metrics,pedestrian environments,and types of infectious diseases using simulation-generated data.Our findings reveal conflicting results among five different metric types in specific environments.More specifically,we observe that,when the randomness of pedestrian trajectories in indoor spaces is low,the closeness centrality exhibits a higher correlation coefficient with infection-based metrics than with contact-based metrics.Furthermore,even within the same pedestrian environment,the likelihood of discrepancies between infection-based metrics and other metrics increases for infectious diseases with low transmission rates.These results highlight the variability in the measured effectiveness of NPIs depending on the chosen metric.To evaluate NPIs accurately,facility managers should consider the type of facility and infectious disease and not solely rely on a single metric.This study provides a simulation model as a tool for future research and improves the reliability of pedestrian-simulation-based NPI effectiveness analysis methods.展开更多
Soft robots have partially or entirely provided versatile opportunities for issues or roles that cannot be addressed by conventional machine robots,although most studies are limited to designs,controls,or physical/mec...Soft robots have partially or entirely provided versatile opportunities for issues or roles that cannot be addressed by conventional machine robots,although most studies are limited to designs,controls,or physical/mechanical motions.Here,we present a transformable,reconfigurable robotic platform created by the integration of magnetically responsive soft composite matrices with deformable multifunctional electronics.Magnetic compounds engineered to undergo phase transition at a low temperature can readily achieve reversible magnetization and conduct various changes of motions and shapes.Thin and flexible electronic system designed with mechanical dynamics does not interfere with movements of the soft electronic robot,and the performances of wireless circuit,sensors,and devices are independent of a variety of activities,all of which are verified by theoretical studies.Demonstration of navigations and electronic operations in an artificial track highlights the potential of the integrated soft robot for on-demand,environments-responsive movements/metamorphoses,and optoelectrical detection and stimulation.Further improvements to a miniaturized,sophisticated system with material options enable in situ monitoring and treatment in envisioned areas such as biomedical implants.展开更多
NiCoCrAlY is usually used as the material to bond-coat in thermal barrier coating systems under high temperatures.Using NiCoCrAlY and adding different amounts of the active element Ti(0,0.1,0.3,and0.5;wt%),the relatio...NiCoCrAlY is usually used as the material to bond-coat in thermal barrier coating systems under high temperatures.Using NiCoCrAlY and adding different amounts of the active element Ti(0,0.1,0.3,and0.5;wt%),the relationship between oxide peg size and thermally grown oxide spalling resistance is ascertained by examining specimens subjected to a cyclic oxidation experiment.Oxide pegs,consisting of a Y-and Ti-rich oxide core and an outer Al_(2) O_(3) sheath,are formed by Ti and A1 successively reacting with oxygen after the rapid generation of Y-rich oxide.The size of the oxide pegs with higher Ti concentrations is on average bigger in the alloy.Severe thermally grown oxide spalling occurred in the0.5 wt% Ti specimen,but in the 0.3 wt% Ti specimen,it displayed the best adherence with the alloy due to the presence of fine pegs.Cavities existed at the interface between the inner oxide core and outer Al_(2) O_(3) sheath of larger pegs serve as microcrack sources and further induce severe scale failure combined with the initial interface crack between the scale and alloy.展开更多
In this study,high entropy metallic glasses(HEMGs)were developed through a combination of concepts for designing metallic glasses(main element+transition metal+metalloid element)and high-entropy alloys(more than five ...In this study,high entropy metallic glasses(HEMGs)were developed through a combination of concepts for designing metallic glasses(main element+transition metal+metalloid element)and high-entropy alloys(more than five elements,each element having an atomic concentration between 5 at.%and 35 at.%).The developed metallic glass alloys are composed of Co-Fe-Ni main elements,transition metals(Cr,Mo)and metalloid elements(C,B).Moreover,the present work reports the thermal,mechanical and magnetic properties of(CoFeNi)(50)(CrMo)(50-x)(CB)x alloys with x=20,25,30.The developed as-spun HEMGs exhibit typical paramagnetic properties even for a high amount of ferromagnetic elements(Co,Fe,and Ni)and have high elastic modulus(103–160 GPa)and hardness(14–27 GPa),thus possessing mechanical properties similar to well-known Co-based metallic glasses(Co-Cr-Mo-C-B system).In addition,some of the bulk samples prepared with a diameter of 2 mm form bulk metallic glasses with a high compressive strength around 3.5 GPa.The mechanisms determining the stability of the supercooled liquid,as well as the paramagnetic and mechanical properties for the developed non-equiatomic HEMGs,are discussed.展开更多
The study of photonic sintering has gained interest based on the advantages of fast processing at room temperature.However,printed electronics made from photonic sintering with an intensive pulsed light(IPL)energy sou...The study of photonic sintering has gained interest based on the advantages of fast processing at room temperature.However,printed electronics made from photonic sintering with an intensive pulsed light(IPL)energy source exhibit more mechanical instability than those made from conventional thermal sintering processes.To solve the mechanical instability problems,we fabricated Ag flake hybrid pastes with a variety of concentrations of Ag flake(0,25,50,75,and 100 wt.%).All of the screen-printed hybrid Ag circuits were fabricated on polyimide substrates and were sintered at 3.5 MW.Surface porosity was analyzed using the Brunauer-Emmett-Teller method.An IPC(Packaging Electronic Circuits)sliding test was performed to analyze the flexibility of the screen-printed Ag flake hybrid circuits.The adhesion strength of the hybrid circuits was evaluated with a roll-type 90°peel test.The hybrid Ag printed circuit showed improvements in both the flexibility and adhesion strength with the addition of Ag flake.展开更多
Pockets in proteins have been known to be very important for the life process. There have been several studies in the past to automatically extract the pockets from the structure information of known proteins. However...Pockets in proteins have been known to be very important for the life process. There have been several studies in the past to automatically extract the pockets from the structure information of known proteins. However, it is difficult to find a study comparing the precision of the extracted pockets from known pockets on the protein. In this paper, we propose an algorithm for extracting pockets from structure data of proteins and analyze the quality of the algorithm by comparing the extracted pockets with some known pockets. These results in this paper can be used to set the parameter values of the pocket extraction algorithm for getting better results.展开更多
Recently, the development of the Internet of Things (IoT) hasenabled continuous and personal electrocardiogram (ECG) monitoring. In theECG monitoring system, classification plays an important role because it canselect...Recently, the development of the Internet of Things (IoT) hasenabled continuous and personal electrocardiogram (ECG) monitoring. In theECG monitoring system, classification plays an important role because it canselect useful data (i.e., reduce the size of the dataset) and identify abnormaldata that can be used to detect the clinical diagnosis and guide furthertreatment. Since the classification requires computing capability, the ECGdata are usually delivered to the gateway or the server where the classificationis performed based on its computing resource. However, real-time ECG datatransmission continuously consumes battery and network resources, whichare expensive and limited. To mitigate this problem, this paper proposes atiny machine learning (TinyML)-based classification (i.e., TinyCES), wherethe ECG monitoring device performs the classification by itself based onthe machine-learning model, which can reduce the memory and the networkresource usages for the classification. To demonstrate the feasibility, afterwe configure the convolutional neural networks (CNN)-based model usingECG data from the Massachusetts Institute of Technology (MIT)-Beth IsraelHospital (BIH) arrhythmia and the Physikalisch Technische Bundesanstalt(PTB) diagnostic ECG databases, TinyCES is validated using the TinyMLsupportedArduino prototype. The performance results show that TinyCEScan have an approximately 97% detection ratio, which means that it has greatpotential to be a lightweight and resource-efficient ECG monitoring system.展开更多
The graft polymerization of hydrophilic monomers on the surface of hydrophobic PMMA was performed using an electron beam (e-beam). The dose of e-beam irradiation, reaction concentration, temperature, and reaction time...The graft polymerization of hydrophilic monomers on the surface of hydrophobic PMMA was performed using an electron beam (e-beam). The dose of e-beam irradiation, reaction concentration, temperature, and reaction time were used to study the effect of variables on the graft density of poly (ethylene glycol)-methacrylate. The results demonstrated that the weight percentage of graft polymer increased with increasing temperature, time and monomer concentration. However, the weight of the graft polymer did not increase with the increasing dose of e-beam irradiation. The change of the contact angle of the water droplet on the PMMA surface was monitored as a function of a reaction time. The results showed that the contact angle decreased up until a specific time and then leveled off to an approximately constant value after a certain reaction time of the graft polymerization. Transmission electron microscopy proved that the constant value of the contact angle was due to the local survival of surface radicals followed by the perpendicular diffusion of monomers only into the bulk of the surface-modified area on the sheet surface.展开更多
The cell-type continuous electromagnetic radiation system is a demonstration device capable of generating high-power millimeter electromagnetic waves of a specific wavelength and observing their effects on living orga...The cell-type continuous electromagnetic radiation system is a demonstration device capable of generating high-power millimeter electromagnetic waves of a specific wavelength and observing their effects on living organisms.It irradiates a biological sample placed in a 30×30×50 cm^(3)cell with electromagnetic waves in the 3.15-mm-wavelength region(with an output of≥1 W)and analyzes the temperature change of the sample.A vacuum electronic device-based coupled-cavity backward-wave oscillator converts the electron energy of the electron beam into radiofrequency(RF)energy and radiates it to the target through an antenna,increasing the temperature through the absorption of RF energy in the skin.The system causes pain and ultimately reduces combat power.A cell-type continuous electromagnetic radiation system consisting of four parts—an electromagnetic-wave generator,a highvoltage power supply,a test cell,and a system controller—generates an RF signal of≥1 W in a continuous waveform at a 95-GHz center frequency,as well as a chemical solution with a dielectric constant similar to that of the skin of a living organism.An increase of 5°C lasting approximately 10 s was confirmed through an experiment.展开更多
The character of Sn-Bi plating chips,such as the effect of whisker preventing, solder ability,temperature cycle(T/C) test and thermal humidity bias(THB) test result was introduced.The research result shows that the Sn...The character of Sn-Bi plating chips,such as the effect of whisker preventing, solder ability,temperature cycle(T/C) test and thermal humidity bias(THB) test result was introduced.The research result shows that the Sn-Bi plating chips have good effect of prevent whisker from growing,these chips can pass the T/C test and THB test.展开更多
The thin wafer(such as BOC) is often cracked easily after Die-Attach process and large numbers of products in some semiconductor company failed as a result of crack.So it is urgent to get the solution to assure the qu...The thin wafer(such as BOC) is often cracked easily after Die-Attach process and large numbers of products in some semiconductor company failed as a result of crack.So it is urgent to get the solution to assure the quality and increase the yield.This article explained the relation of crack,the chip strength,as well as Die-Attach pin-up speed and how to solve that issue.For example,additional polishing process can significantly decrease the grind mark damage;pin-up speed optimization can make pin-up force best.So linear crack of thin chip can be avoided effectively.展开更多
As the use of cloud storage for various services increases,the amount of private personal information along with data stored in the cloud storage is also increasing.To remotely use the data stored on the cloud storage...As the use of cloud storage for various services increases,the amount of private personal information along with data stored in the cloud storage is also increasing.To remotely use the data stored on the cloud storage,the data to be stored needs to be encrypted for this reason.Since“searchable encryption”is enable to search on the encrypted data without any decryption,it is one of convenient solutions for secure data management.A public key encryption with keyword search(for short,PEKS)is one of searchable encryptions.Abdalla et al.firstly defined IND-CCA security for PEKS to enhance it’s security and proposed consistent IND-CCA secure PEKS based on the“robust”ANO-CCA secure identity-based encryption(IBE).In this paper,we propose two generic constructions of consistent IND-CCA secure PEKS combining(1)a hierarchical identity based encryption(for short,HIBE)and a signature scheme or(2)a HIBE,an encapsulation,and a message authentication code(for short,MAC)scheme.Our generic constructions identify that HIBE requires the security of a signature or a MAC as well as the weaker“ANO-CPA security(resp.,IND-CPA security)”of HIBE than“ANOCCA security(resp.,IND-CCA security)”of IBE required in for achieving IND-CCA secure(resp.,consistent)PEKS.Finally,we prove that our generic constructions satisfy IND-CCA security and consistency under the security models.展开更多
This paper develops a deep learning tool based on neural processes(NPs)called the Peri-Net-Pro,to predict the crack patterns in a moving disk and classifies them according to the classification modes with quantified u...This paper develops a deep learning tool based on neural processes(NPs)called the Peri-Net-Pro,to predict the crack patterns in a moving disk and classifies them according to the classification modes with quantified uncertainties.In particular,image classification and regression studies are conducted by means of convolutional neural networks(CNNs)and NPs.First,the amount and quality of the data are enhanced by using peridynamics to theoretically compensate for the problems of the finite element method(FEM)in generating crack pattern images.Second,case studies are conducted with the prototype microelastic brittle(PMB),linear peridynamic solid(LPS),and viscoelastic solid(VES)models obtained by using the peridynamic theory.The case studies are performed to classify the images by using CNNs and determine the suitability of the PMB,LBS,and VES models.Finally,a regression analysis is performed on the crack pattern images with NPs to predict the crack patterns.The regression analysis results confirm that the variance decreases when the number of epochs increases by using the NPs.The training results gradually improve,and the variance ranges decrease to less than 0.035.The main finding of this study is that the NPs enable accurate predictions,even with missing or insufficient training data.The results demonstrate that if the context points are set to the 10th,100th,300th,and 784th,the training information is deliberately omitted for the context points of the 10th,100th,and 300th,and the predictions are different when the context points are significantly lower.However,the comparison of the results of the 100th and 784th context points shows that the predicted results are similar because of the Gaussian processes in the NPs.Therefore,if the NPs are employed for training,the missing information of the training data can be supplemented to predict the results.展开更多
基金financially supported by the National Research Foundation of Korea(no.NRF-2021R1A2C2010781)grant funded by the Korean Government(Ministry of Science and ICT)Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(no.P0012451,The Competency Development Program for Industry Specialist)Korea Government(MOTIE)(no.P0020966,HRD Program for Industrial Innovation).
文摘Neuromorphic computing devices leveraging HfO_(2) and ZrO_(2) materials have recently garnered significant attention due to their potential for brain-inspired computing systems.In this study,we present a novel trilayer Pt/HfO_(2)/ZrO_(2-x)/HfO_(2)/TiN memristor,engineered with a ZrO_(2-x) oxygen vacancy reservoir(OVR)layer fabricated via radio frequency(RF)sputtering under controlled oxygen ambient.The incorporation of the ZrO_(2-x) OVR layer enables enhanced resistive switching characteristics,including a high ON/OFF ratio(∼8000),excellent uniformity,robust data retention(>105 s),and multilevel storage capabilities.Furthermore,the memristor demonstrates superior synaptic plasticity with linear long-term potentiation(LTP)and depression(LTD),achieving low non-linearity values of 1.36(LTP)and 0.66(LTD),and a recognition accuracy of 95.3%in an MNIST dataset simulation.The unique properties of the ZrO_(2-x) layer,particularly its ability to act as a dynamic oxygen vacancy reservoir,significantly enhance synaptic performance by stabilizing oxygen vacancy migration.These findings establish the OVR-trilayer memristor as a promising candidate for future neuromorphic computing and high-performance memory applications.
基金supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Grant Nos.RS-2024-00403639 and RS2024-00411904)。
文摘Artificial sensory systems(ASS)are pivotal to next-generation extended reality technologies,now evolving into flexible platforms for comfortable wear and immersive user experiences,while ensuring high performance and operational reliability.To address these demands,metal-based nanoparticles(NPs),such as noble metal,oxide,and multi-elemental NPs,have been extensively incorporated into functional materials of sensory and synaptic devices due to their tunable optical,electrical,and chemical properties,enhancing sensory precision,stability,and environmental adaptability.However,traditional NP fabrication methods often involve complex processing,residual contaminants,and scalability issues,limiting their effectiveness in ASS applications.State-of-the-art laser ablation in liquids(LAL)presents a promising alternative,offering scalable production of surfactant-free NPs with customizable physicochemical properties,though their application in electronics remains underexplored.This review delves into the transformative potential of LAL-fabricated NPs in ASS,covering the fundamental mechanisms of LAL,the role of process parameters,the derivative strategies for size modulation,the diversity of metal-based NPs,their applications in sensory and synaptic devices,and the challenges and perspectives for meeting industrial standards.Bridging the gap between LAL and ASS is poised to revolutionize both industrial manufacturing and academic research by offering scalable solutions to overcome intrinsic tradeoffs between flexibility and performance,fostering innovations in human-centric,immersive electronics.
基金financially supported by National R&D Program(RS-2024-00405016)Nano Material Technology Development Program(2022M3HA1A01011993)financially supported by Samsung Electronics Co.,Ltd.
文摘The increasing importance of high-purity isopropyl alcohol(IPA)in semiconductor processing technology has led to a higher demand for technologies capable of detecting impurities in IPA.Although accurate and various impurity detection technologies have been developed,most of them have limitations in real-time and repeatable detection of impurities.Herein,for the first time,surface plasmon resonance(SPR)sensor was developed utilizing graphene transferred Au film(Au/graphene)to detect sub-ppm levels of 2,4-dinitrophenol(2,4-DNP)dissolved in IPA and this sensor demonstrates the ability to detect 2,4-DNP in real-time with great reversibility.The adsorption of 2,4-DNP to graphene is found to be stronger than that for Au film because of noncovalent graphene p–p stacking interaction,and the effect of graphene is demonstrated through density function theory(DFT)calculations and enhancement in sensing performance of Au/graphene sensor.Additionally,the presence of noncovalent p–p stacking interaction between 2,4-DNP and graphene has been demonstrated by confirming the p-doping effect of graphene-based solution field-effect transistor measurements and consecutive Raman spectra analysis.This study offers experimental and theoretical insights into the adsorption kinetics of 2,4-DNP dissolved in IPA and provides promising perspectives for real-time sensing technology utilizing label-free graphene to detect impurities in high-purity cleaning agents.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Ministry of Science and ICT(MSIT),Republic of Korea(1711185759).
文摘Governments worldwide have implemented non-pharmaceutical interventions(NPIs)to control the spread of coronavirus disease 2019(COVID-19),and it is crucial to accurately assess the effectiveness of such measures.Many studies have quantified the risk of infection transmission and used simulations to compare the risk before and after the implementation of NPIs to judge policies’effectiveness.However,the choice of metric used to quantify the risk can lead to different conclusions regarding the effectiveness of a policy.In this study,we analyze the correlation between different transmission-risk metrics,pedestrian environments,and types of infectious diseases using simulation-generated data.Our findings reveal conflicting results among five different metric types in specific environments.More specifically,we observe that,when the randomness of pedestrian trajectories in indoor spaces is low,the closeness centrality exhibits a higher correlation coefficient with infection-based metrics than with contact-based metrics.Furthermore,even within the same pedestrian environment,the likelihood of discrepancies between infection-based metrics and other metrics increases for infectious diseases with low transmission rates.These results highlight the variability in the measured effectiveness of NPIs depending on the chosen metric.To evaluate NPIs accurately,facility managers should consider the type of facility and infectious disease and not solely rely on a single metric.This study provides a simulation model as a tool for future research and improves the reliability of pedestrian-simulation-based NPI effectiveness analysis methods.
基金supported by the Korea Institute of Science and Technology(KIST)Institutional Program(Project No.2E32501-23-106)the National Research Foundation of Korea(NRF)grant funded by the Korea government(the Ministry of Science,ICT,MSIT)(RS-2022-00165524)+2 种基金the development of technologies for electroceuticals of National Research Foundation(NRF)funded by the Korean government(MSIT)(RS-2023-00220534)ICT Creative Consilience program through the Institute of Information&Communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(IITP-2024-2020-0-01819)Start up Pioneering in Research and Innovation(SPRINT)through the Commercialization Promotion Agency for R&D Outcomes(COMPA)grant funded by the Korea government(Ministry of Science and ICT)(1711198921).
文摘Soft robots have partially or entirely provided versatile opportunities for issues or roles that cannot be addressed by conventional machine robots,although most studies are limited to designs,controls,or physical/mechanical motions.Here,we present a transformable,reconfigurable robotic platform created by the integration of magnetically responsive soft composite matrices with deformable multifunctional electronics.Magnetic compounds engineered to undergo phase transition at a low temperature can readily achieve reversible magnetization and conduct various changes of motions and shapes.Thin and flexible electronic system designed with mechanical dynamics does not interfere with movements of the soft electronic robot,and the performances of wireless circuit,sensors,and devices are independent of a variety of activities,all of which are verified by theoretical studies.Demonstration of navigations and electronic operations in an artificial track highlights the potential of the integrated soft robot for on-demand,environments-responsive movements/metamorphoses,and optoelectrical detection and stimulation.Further improvements to a miniaturized,sophisticated system with material options enable in situ monitoring and treatment in envisioned areas such as biomedical implants.
基金financially supported by the Tsinghua University Initiative Scientific Research Program and the National Magnetic Confinement Fusion Energy Research Project of China(No.2015GB118001)。
文摘NiCoCrAlY is usually used as the material to bond-coat in thermal barrier coating systems under high temperatures.Using NiCoCrAlY and adding different amounts of the active element Ti(0,0.1,0.3,and0.5;wt%),the relationship between oxide peg size and thermally grown oxide spalling resistance is ascertained by examining specimens subjected to a cyclic oxidation experiment.Oxide pegs,consisting of a Y-and Ti-rich oxide core and an outer Al_(2) O_(3) sheath,are formed by Ti and A1 successively reacting with oxygen after the rapid generation of Y-rich oxide.The size of the oxide pegs with higher Ti concentrations is on average bigger in the alloy.Severe thermally grown oxide spalling occurred in the0.5 wt% Ti specimen,but in the 0.3 wt% Ti specimen,it displayed the best adherence with the alloy due to the presence of fine pegs.Cavities existed at the interface between the inner oxide core and outer Al_(2) O_(3) sheath of larger pegs serve as microcrack sources and further induce severe scale failure combined with the initial interface crack between the scale and alloy.
基金supported by the Technology Innovation Program(No.10063052,Development of advanced nano-micron coating material and coated cutting tool for Hard-to-Cut)funded By Ministry of Trade,Industry and Energy(MOTIE,Korea)+1 种基金the Basic Research Laboratory Program through the Ministry of Education of the Republic of Korea(No.2019R1A4A1026125)support through the European Research Council under the Advanced Grant“INTERLHYB”—Next Generation of Complex Metallic Materials in Intelligent Hybrid Structures”(No.ERC-2013-ADG-340025)is gratefully acknowledged。
文摘In this study,high entropy metallic glasses(HEMGs)were developed through a combination of concepts for designing metallic glasses(main element+transition metal+metalloid element)and high-entropy alloys(more than five elements,each element having an atomic concentration between 5 at.%and 35 at.%).The developed metallic glass alloys are composed of Co-Fe-Ni main elements,transition metals(Cr,Mo)and metalloid elements(C,B).Moreover,the present work reports the thermal,mechanical and magnetic properties of(CoFeNi)(50)(CrMo)(50-x)(CB)x alloys with x=20,25,30.The developed as-spun HEMGs exhibit typical paramagnetic properties even for a high amount of ferromagnetic elements(Co,Fe,and Ni)and have high elastic modulus(103–160 GPa)and hardness(14–27 GPa),thus possessing mechanical properties similar to well-known Co-based metallic glasses(Co-Cr-Mo-C-B system).In addition,some of the bulk samples prepared with a diameter of 2 mm form bulk metallic glasses with a high compressive strength around 3.5 GPa.The mechanisms determining the stability of the supercooled liquid,as well as the paramagnetic and mechanical properties for the developed non-equiatomic HEMGs,are discussed.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2019R1A6A1A03033215)supported by“Human Resources Program in Energy Technology”of the Korea Institute of Energy Technology Evaluation and Planning(KETEP),granted financial resource from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20174030201800)。
文摘The study of photonic sintering has gained interest based on the advantages of fast processing at room temperature.However,printed electronics made from photonic sintering with an intensive pulsed light(IPL)energy source exhibit more mechanical instability than those made from conventional thermal sintering processes.To solve the mechanical instability problems,we fabricated Ag flake hybrid pastes with a variety of concentrations of Ag flake(0,25,50,75,and 100 wt.%).All of the screen-printed hybrid Ag circuits were fabricated on polyimide substrates and were sintered at 3.5 MW.Surface porosity was analyzed using the Brunauer-Emmett-Teller method.An IPC(Packaging Electronic Circuits)sliding test was performed to analyze the flexibility of the screen-printed Ag flake hybrid circuits.The adhesion strength of the hybrid circuits was evaluated with a roll-type 90°peel test.The hybrid Ag printed circuit showed improvements in both the flexibility and adhesion strength with the addition of Ag flake.
基金Project supported by Creative Research Initiative from the Ministry of Science and Technology (MOST), Korea. BHAK Jonghwa is supported by Biogreen21 Fund and MOST Funds, Korea
文摘Pockets in proteins have been known to be very important for the life process. There have been several studies in the past to automatically extract the pockets from the structure information of known proteins. However, it is difficult to find a study comparing the precision of the extracted pockets from known pockets on the protein. In this paper, we propose an algorithm for extracting pockets from structure data of proteins and analyze the quality of the algorithm by comparing the extracted pockets with some known pockets. These results in this paper can be used to set the parameter values of the pocket extraction algorithm for getting better results.
基金supported by National Research Foundation (NRF)of Korea Grant funded by the Korean Government (MSIP) (No.2022R1F1A1063183).
文摘Recently, the development of the Internet of Things (IoT) hasenabled continuous and personal electrocardiogram (ECG) monitoring. In theECG monitoring system, classification plays an important role because it canselect useful data (i.e., reduce the size of the dataset) and identify abnormaldata that can be used to detect the clinical diagnosis and guide furthertreatment. Since the classification requires computing capability, the ECGdata are usually delivered to the gateway or the server where the classificationis performed based on its computing resource. However, real-time ECG datatransmission continuously consumes battery and network resources, whichare expensive and limited. To mitigate this problem, this paper proposes atiny machine learning (TinyML)-based classification (i.e., TinyCES), wherethe ECG monitoring device performs the classification by itself based onthe machine-learning model, which can reduce the memory and the networkresource usages for the classification. To demonstrate the feasibility, afterwe configure the convolutional neural networks (CNN)-based model usingECG data from the Massachusetts Institute of Technology (MIT)-Beth IsraelHospital (BIH) arrhythmia and the Physikalisch Technische Bundesanstalt(PTB) diagnostic ECG databases, TinyCES is validated using the TinyMLsupportedArduino prototype. The performance results show that TinyCEScan have an approximately 97% detection ratio, which means that it has greatpotential to be a lightweight and resource-efficient ECG monitoring system.
文摘The graft polymerization of hydrophilic monomers on the surface of hydrophobic PMMA was performed using an electron beam (e-beam). The dose of e-beam irradiation, reaction concentration, temperature, and reaction time were used to study the effect of variables on the graft density of poly (ethylene glycol)-methacrylate. The results demonstrated that the weight percentage of graft polymer increased with increasing temperature, time and monomer concentration. However, the weight of the graft polymer did not increase with the increasing dose of e-beam irradiation. The change of the contact angle of the water droplet on the PMMA surface was monitored as a function of a reaction time. The results showed that the contact angle decreased up until a specific time and then leveled off to an approximately constant value after a certain reaction time of the graft polymerization. Transmission electron microscopy proved that the constant value of the contact angle was due to the local survival of surface radicals followed by the perpendicular diffusion of monomers only into the bulk of the surface-modified area on the sheet surface.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2021M2E8A1038938,No.NRF-2021R1F1A1048374,and No.NRF-2016R1A3B1908336)supported by a grant of the Korea Institute of Radiological and Medical Sciences(KIRAMS),funded by the Ministry of Science and ICT(MSIT),Republic of Korea(No.50051—2021,No.50623—2021)。
文摘The cell-type continuous electromagnetic radiation system is a demonstration device capable of generating high-power millimeter electromagnetic waves of a specific wavelength and observing their effects on living organisms.It irradiates a biological sample placed in a 30×30×50 cm^(3)cell with electromagnetic waves in the 3.15-mm-wavelength region(with an output of≥1 W)and analyzes the temperature change of the sample.A vacuum electronic device-based coupled-cavity backward-wave oscillator converts the electron energy of the electron beam into radiofrequency(RF)energy and radiates it to the target through an antenna,increasing the temperature through the absorption of RF energy in the skin.The system causes pain and ultimately reduces combat power.A cell-type continuous electromagnetic radiation system consisting of four parts—an electromagnetic-wave generator,a highvoltage power supply,a test cell,and a system controller—generates an RF signal of≥1 W in a continuous waveform at a 95-GHz center frequency,as well as a chemical solution with a dielectric constant similar to that of the skin of a living organism.An increase of 5°C lasting approximately 10 s was confirmed through an experiment.
文摘The character of Sn-Bi plating chips,such as the effect of whisker preventing, solder ability,temperature cycle(T/C) test and thermal humidity bias(THB) test result was introduced.The research result shows that the Sn-Bi plating chips have good effect of prevent whisker from growing,these chips can pass the T/C test and THB test.
文摘The thin wafer(such as BOC) is often cracked easily after Die-Attach process and large numbers of products in some semiconductor company failed as a result of crack.So it is urgent to get the solution to assure the quality and increase the yield.This article explained the relation of crack,the chip strength,as well as Die-Attach pin-up speed and how to solve that issue.For example,additional polishing process can significantly decrease the grind mark damage;pin-up speed optimization can make pin-up force best.So linear crack of thin chip can be avoided effectively.
文摘As the use of cloud storage for various services increases,the amount of private personal information along with data stored in the cloud storage is also increasing.To remotely use the data stored on the cloud storage,the data to be stored needs to be encrypted for this reason.Since“searchable encryption”is enable to search on the encrypted data without any decryption,it is one of convenient solutions for secure data management.A public key encryption with keyword search(for short,PEKS)is one of searchable encryptions.Abdalla et al.firstly defined IND-CCA security for PEKS to enhance it’s security and proposed consistent IND-CCA secure PEKS based on the“robust”ANO-CCA secure identity-based encryption(IBE).In this paper,we propose two generic constructions of consistent IND-CCA secure PEKS combining(1)a hierarchical identity based encryption(for short,HIBE)and a signature scheme or(2)a HIBE,an encapsulation,and a message authentication code(for short,MAC)scheme.Our generic constructions identify that HIBE requires the security of a signature or a MAC as well as the weaker“ANO-CPA security(resp.,IND-CPA security)”of HIBE than“ANOCCA security(resp.,IND-CCA security)”of IBE required in for achieving IND-CCA secure(resp.,consistent)PEKS.Finally,we prove that our generic constructions satisfy IND-CCA security and consistency under the security models.
基金Project supported by the National Science Foundation of U.S.A.(Nos.DMS-1555072,DMS-2053746DMS-2134209)+1 种基金the Brookhaven National Laboratory of U.S.A.(No.382247)U.S.Department of Energy(DOE)Office of Science Advanced Scientific Computing Research Program(Nos.DESC0021142 and DE-SC0023161)。
文摘This paper develops a deep learning tool based on neural processes(NPs)called the Peri-Net-Pro,to predict the crack patterns in a moving disk and classifies them according to the classification modes with quantified uncertainties.In particular,image classification and regression studies are conducted by means of convolutional neural networks(CNNs)and NPs.First,the amount and quality of the data are enhanced by using peridynamics to theoretically compensate for the problems of the finite element method(FEM)in generating crack pattern images.Second,case studies are conducted with the prototype microelastic brittle(PMB),linear peridynamic solid(LPS),and viscoelastic solid(VES)models obtained by using the peridynamic theory.The case studies are performed to classify the images by using CNNs and determine the suitability of the PMB,LBS,and VES models.Finally,a regression analysis is performed on the crack pattern images with NPs to predict the crack patterns.The regression analysis results confirm that the variance decreases when the number of epochs increases by using the NPs.The training results gradually improve,and the variance ranges decrease to less than 0.035.The main finding of this study is that the NPs enable accurate predictions,even with missing or insufficient training data.The results demonstrate that if the context points are set to the 10th,100th,300th,and 784th,the training information is deliberately omitted for the context points of the 10th,100th,and 300th,and the predictions are different when the context points are significantly lower.However,the comparison of the results of the 100th and 784th context points shows that the predicted results are similar because of the Gaussian processes in the NPs.Therefore,if the NPs are employed for training,the missing information of the training data can be supplemented to predict the results.
