Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fu...Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen bubbles.This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications.In addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance.Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor.Here we review the design and recent advancements of metallic degradable micromotors.Furthermore,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications.Moreover,we discuss micromotors’efficacy in detecting and destroying environmental pollutants.Finally,we address the limitations and future research directions of degradable metallic micromotors.展开更多
Finger Braille is one of the tactual communication media of deafblind people. In one-handed Finger Braille, a sender dots the left part of the Braille code on the Distal Interphalangeal （DIP） joints of the index, mi...Finger Braille is one of the tactual communication media of deafblind people. In one-handed Finger Braille, a sender dots the left part of the Braille code on the Distal Interphalangeal （DIP） joints of the index, middle and ring fingers of a receiver, and subsequently dots the right part of the Braille code on the Proximal Interphalangeal （PIP）joints of the same fingers. Because there is a small number of non-disabled people who are skilled in Finger Braille, deafblind people communicate in this medium only through an interpreter. We have been developing a Finger Braille recognition system using small piezoelectric accelerometers worn by the receiver To recognize the dotted positions （DIP or PIP joints）, we have made a hypothesis that the dotting on the DIP joints causes a hard impact, and the dotting on the PIP joints causes a soft impact, when the receiver＇s hand forms a natural longitudinal arch on the desk. The difference of each impact is indicated by its damping amplitude ratio. In this paper, a measurement experiment about the postures of the receiver＇s hand was conducted. The postures of the receiver＇s hand were as follows： forming the natural longitudinal arch on the desk and fully contacting the desk. As a result, the dotting on the DIP joints of both postures caused the hard impacts; the dotting on the PIP joints caused the soft impact when the receiver＇s hand formed the natural longitudinal arch; the dotting on the PIP joints caused the hard impact when the receiver＇s hand fully contacted the desk. Therefore, we could verify the hypothesis.展开更多
The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining...The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining has an influence on accuracy and efficiency and is an important factor. The measurement system for measuring the forms of die and mold at all times is essential in order to machine the die and mold with high accuracy and efficiency. However, the problems of management and operation errors are found in compensating process of die and mold machining. In this paper, an online machining and measurement system in die and mold manufacturing is developed in order to overcome these problems. In this online system, 2-axis control system is added to a surface roughness measuring instrument, and both NC machining program and measured data are linked and controlled using a same computer. Therefore, the machining and measurement can be recognized for consistent process, and can be realized on the machine. This system has the advantages such as the high accuracy, low-price, and online convenience and so on. The possibility of practical use of this online system was investigated by fundamental experiments.展开更多
In this contribution,we reply to comments made by Tkach et al.in our publication J.Materiomics 2023;9:609.The main interest of our work is to synthesize a lead-free material,SrTi_(2)O_(5)(STO),and then utilize it in t...In this contribution,we reply to comments made by Tkach et al.in our publication J.Materiomics 2023;9:609.The main interest of our work is to synthesize a lead-free material,SrTi_(2)O_(5)(STO),and then utilize it in the formation of composites and finally design the piezoelectric nanogenerator(PENG)for self-powered sensor applications.The authors have observed the presence of piezoelectric voltage and current output from the PENG.The authors humbly indicate that the PENG devices were poled using a DC poling setup as conditions mentioned in J.Materiomics 2023;9:609(Panda et al.,2023)[1].The doping of STO into the PDMS increased from 2% to 20%(in mass).In this process,the piezoelectric output of the PENG device was observed to be highest for 15%(in mass)STO-PDMS composite.Besides,we agree with the comment raised by Tkach et al.,and further we have addressed the issues in a step-by-step response as follows.展开更多
The paper concerns a research into dynamic properties of the steel suspension bridge across Opolska Street in Krakow, Poland. Parameter identification was carried out with the application of the nonlinear system ident...The paper concerns a research into dynamic properties of the steel suspension bridge across Opolska Street in Krakow, Poland. Parameter identification was carried out with the application of the nonlinear system identification method on the basis of system responses to exploitational excitation resulting from pedestrian traffic. In order to verify obtained results, on the basis of the geometrical and material properties of the considered system, the FEM （finite elements model） was created. Created FEM model was updated through the comparison with the model determined by the use of experimental modal analysis method and then applied to analytical evaluation of the considered suspension bridge natural frequencies.展开更多
Morphotropic phase boundary(MPB)-based ceramics are excellent for energy harvesting due to their enhanced physical properties at phase boundaries,broad operating temperature range,and ability to customize properties f...Morphotropic phase boundary(MPB)-based ceramics are excellent for energy harvesting due to their enhanced physical properties at phase boundaries,broad operating temperature range,and ability to customize properties for efficient conversion of mechanical energy into electrical energy.In this work,Bi_(1–x)Na_(x)Fe_(1–x)Nb_(x)O_(3)(x=0.20,0.30,0.32 and 0.40,BNFNO abbreviation)based ceramics were synthesized using a solid-state route and blended with Polydimethylsiloxane(PDMS)to achieve flexible composites.Various material characterization and energy harvesting were performed by designing a hybrid piezoelectric(PENG)-triboelectric(TENG)device.The voltage and current of PENG,TENG,and hybrid bearing same device area(2 cm×2 cm)were recorded as 11 V/0.3μA;60 V/0.7μA;110 V/2.2μA.The strategies for enhancing the output performance of the hybrid device were evaluated,such as increased surface area(creating micro-roughness and porous morphology)and increasing electrode size and multi-layer hybrid device formation.The self-powered acceleration monitoring was demonstrated using the hybrid device.Further,the low-frequency-based wave energy is converted into electrical energy,confirming the usage of hybrid PENG-TENG devices as a base for battery-free sensors and blue energy harvesting.展开更多
Lead-free piezoelectric ceramic is a promising material for energy harvesters,as they have superior electromechanical,ferroelectric,and piezoelectric properties.In addition,piezoelectric ceramics can be blended with p...Lead-free piezoelectric ceramic is a promising material for energy harvesters,as they have superior electromechanical,ferroelectric,and piezoelectric properties.In addition,piezoelectric ceramics can be blended with polymer to achieve high-flexibility polymer-ceramic composites,providing mechanical robustness and stability.In this context,a new lead-free ferroelectric material,having the chemical formula SrTi_(2)O_(5)(STO),was synthesized using a high-temperature solid-state reaction.Detailed analyses of the structural,morphological,and electrical properties of the synthesized material were performed.STO crystallizes with orthorhombic symmetry and space group of Cmm2.The frequency and temperature-dependent dielectric parameters were evaluated,and impedance spectroscopy shed light on the charge dynamics.The PDMS-STO composites at different mass fraction of the STO were prepared using a solvent casting route,and a corresponding piezoelectric nanogenerator(PENG)was developed.The electrical output of the different PENG by varying massfractions of STO in PDMS and varying force were investigated.The 15%(in mass)PENG device delivered the highest peak-to-peak voltage,current,and power density of 25 V,92 nA,and 0.64 mW@500 MU,respectively.The biomechanical energy harvesting using the PENG device by daily human motions,bending of the device,and attaching the device to laboratory equipment was demonstrated.Later the PENG device was attached to the human throat region,and snoring signals were recorded.A classification model was designed employing the convolutional neural network(CNN)model.Efforts have been laid to differentiate between normal and abnormal snores,which could help the patient with screening and early disease detection,contributing to self-powered healthcare applications.展开更多
Surface electromyography(sEMG)sensors play a critical role in diagnosing muscle conditions and enabling prosthetic device control,especially for lower extremity robotic legs.However,challenges arise when utilizing suc...Surface electromyography(sEMG)sensors play a critical role in diagnosing muscle conditions and enabling prosthetic device control,especially for lower extremity robotic legs.However,challenges arise when utilizing such sensors on residual limbs within a silicon liner worn by amputees,where dynamic pressure,narrow space,and perspiration can negatively affect sensor performance.Existing commercial sEMG sensors and newly developed sensors are unsuitable due to size and thickness,or susceptible to damage in this environment.In this paper,our sEMG sensors are tailored for amputees wearing sockets,prioritizing breathability,durability,and reliable recording performance.By employing porous PDMS and Silbione substrates,our design achieves exceptional permeability and adhesive properties.The serpentine electrode pattern and design are optimized to improve stretchability,durability,and effective contact area,resulting in a higher signal-to-noise ratio(SNR)than conventional electrodes.Notably,our proposed sensors wirelessly enable to control of a robotic leg for amputees,demonstrating its practical feasibility and expecting to drive forward neuro-prosthetic control in the clinical research field near future.展开更多
The Fabry-Pérot interferometer,a fundamental component in optoelectronic systems,offers interesting applications such as sensors,lasers,and filters.In this work,we show a tunable Fabry-Pérot cavity consistin...The Fabry-Pérot interferometer,a fundamental component in optoelectronic systems,offers interesting applications such as sensors,lasers,and filters.In this work,we show a tunable Fabry-Pérot cavity consisting of tunable Sagnac loop reflectors(SLRs)and phase shifters based on electrostatic microelectromechanical(MEMS)actuator.The fabrication process of the device is compatible with the standard wafer-level silicon photonics fabrication processes.This electrostatic actuation mechanism provides well-balanced,scalable pathways for efficient tuning methodologies.The extinction ratio of the continuously tunable SLRs’reflectivity is larger than 20 dB.Full 2πphase shifting is achieved,and response times of all the components are less than 25μs.Both actuators have extremely low static power,measuring under 20 fW and the energy needed for tuning is both below 20 pJ.展开更多
基金the National Convergence Research of Scientific Challenges through the National Research Foundation of Korea(NRF)the DGIST R&D Program(No.2021M3F7A1082275 and 23-CoE-BT-02)funded by the Ministry of Science and ICT.
文摘Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen bubbles.This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications.In addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance.Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor.Here we review the design and recent advancements of metallic degradable micromotors.Furthermore,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications.Moreover,we discuss micromotors’efficacy in detecting and destroying environmental pollutants.Finally,we address the limitations and future research directions of degradable metallic micromotors.
文摘Finger Braille is one of the tactual communication media of deafblind people. In one-handed Finger Braille, a sender dots the left part of the Braille code on the Distal Interphalangeal （DIP） joints of the index, middle and ring fingers of a receiver, and subsequently dots the right part of the Braille code on the Proximal Interphalangeal （PIP）joints of the same fingers. Because there is a small number of non-disabled people who are skilled in Finger Braille, deafblind people communicate in this medium only through an interpreter. We have been developing a Finger Braille recognition system using small piezoelectric accelerometers worn by the receiver To recognize the dotted positions （DIP or PIP joints）, we have made a hypothesis that the dotting on the DIP joints causes a hard impact, and the dotting on the PIP joints causes a soft impact, when the receiver＇s hand forms a natural longitudinal arch on the desk. The difference of each impact is indicated by its damping amplitude ratio. In this paper, a measurement experiment about the postures of the receiver＇s hand was conducted. The postures of the receiver＇s hand were as follows： forming the natural longitudinal arch on the desk and fully contacting the desk. As a result, the dotting on the DIP joints of both postures caused the hard impacts; the dotting on the PIP joints caused the soft impact when the receiver＇s hand formed the natural longitudinal arch; the dotting on the PIP joints caused the hard impact when the receiver＇s hand fully contacted the desk. Therefore, we could verify the hypothesis.
文摘The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining has an influence on accuracy and efficiency and is an important factor. The measurement system for measuring the forms of die and mold at all times is essential in order to machine the die and mold with high accuracy and efficiency. However, the problems of management and operation errors are found in compensating process of die and mold machining. In this paper, an online machining and measurement system in die and mold manufacturing is developed in order to overcome these problems. In this online system, 2-axis control system is added to a surface roughness measuring instrument, and both NC machining program and measured data are linked and controlled using a same computer. Therefore, the machining and measurement can be recognized for consistent process, and can be realized on the machine. This system has the advantages such as the high accuracy, low-price, and online convenience and so on. The possibility of practical use of this online system was investigated by fundamental experiments.
文摘In this contribution,we reply to comments made by Tkach et al.in our publication J.Materiomics 2023;9:609.The main interest of our work is to synthesize a lead-free material,SrTi_(2)O_(5)(STO),and then utilize it in the formation of composites and finally design the piezoelectric nanogenerator(PENG)for self-powered sensor applications.The authors have observed the presence of piezoelectric voltage and current output from the PENG.The authors humbly indicate that the PENG devices were poled using a DC poling setup as conditions mentioned in J.Materiomics 2023;9:609(Panda et al.,2023)[1].The doping of STO into the PDMS increased from 2% to 20%(in mass).In this process,the piezoelectric output of the PENG device was observed to be highest for 15%(in mass)STO-PDMS composite.Besides,we agree with the comment raised by Tkach et al.,and further we have addressed the issues in a step-by-step response as follows.
文摘The paper concerns a research into dynamic properties of the steel suspension bridge across Opolska Street in Krakow, Poland. Parameter identification was carried out with the application of the nonlinear system identification method on the basis of system responses to exploitational excitation resulting from pedestrian traffic. In order to verify obtained results, on the basis of the geometrical and material properties of the considered system, the FEM （finite elements model） was created. Created FEM model was updated through the comparison with the model determined by the use of experimental modal analysis method and then applied to analytical evaluation of the considered suspension bridge natural frequencies.
基金This work is supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)(2021R1C1C1011588)funded by the Ministry of Science and ICT of Korea.HJ Kim was supported by the Ministry of Trade,Industry and Energy of Korea(RS-2023-00231350)+2 种基金YKM acknowledges the funding by Interreg Deutschland-Denmark with money from the European Regional Development Fund,project number 096-1.1-18(Access and Acceleration)N.Vittayakorn was funded by KMITL under grant No.KREF11650Z Jagličićwas supported by the Slovenian Research Agency(Grant No.P2-0348).
文摘Morphotropic phase boundary(MPB)-based ceramics are excellent for energy harvesting due to their enhanced physical properties at phase boundaries,broad operating temperature range,and ability to customize properties for efficient conversion of mechanical energy into electrical energy.In this work,Bi_(1–x)Na_(x)Fe_(1–x)Nb_(x)O_(3)(x=0.20,0.30,0.32 and 0.40,BNFNO abbreviation)based ceramics were synthesized using a solid-state route and blended with Polydimethylsiloxane(PDMS)to achieve flexible composites.Various material characterization and energy harvesting were performed by designing a hybrid piezoelectric(PENG)-triboelectric(TENG)device.The voltage and current of PENG,TENG,and hybrid bearing same device area(2 cm×2 cm)were recorded as 11 V/0.3μA;60 V/0.7μA;110 V/2.2μA.The strategies for enhancing the output performance of the hybrid device were evaluated,such as increased surface area(creating micro-roughness and porous morphology)and increasing electrode size and multi-layer hybrid device formation.The self-powered acceleration monitoring was demonstrated using the hybrid device.Further,the low-frequency-based wave energy is converted into electrical energy,confirming the usage of hybrid PENG-TENG devices as a base for battery-free sensors and blue energy harvesting.
基金Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT of Korea(2021R1C1C1011588).
文摘Lead-free piezoelectric ceramic is a promising material for energy harvesters,as they have superior electromechanical,ferroelectric,and piezoelectric properties.In addition,piezoelectric ceramics can be blended with polymer to achieve high-flexibility polymer-ceramic composites,providing mechanical robustness and stability.In this context,a new lead-free ferroelectric material,having the chemical formula SrTi_(2)O_(5)(STO),was synthesized using a high-temperature solid-state reaction.Detailed analyses of the structural,morphological,and electrical properties of the synthesized material were performed.STO crystallizes with orthorhombic symmetry and space group of Cmm2.The frequency and temperature-dependent dielectric parameters were evaluated,and impedance spectroscopy shed light on the charge dynamics.The PDMS-STO composites at different mass fraction of the STO were prepared using a solvent casting route,and a corresponding piezoelectric nanogenerator(PENG)was developed.The electrical output of the different PENG by varying massfractions of STO in PDMS and varying force were investigated.The 15%(in mass)PENG device delivered the highest peak-to-peak voltage,current,and power density of 25 V,92 nA,and 0.64 mW@500 MU,respectively.The biomechanical energy harvesting using the PENG device by daily human motions,bending of the device,and attaching the device to laboratory equipment was demonstrated.Later the PENG device was attached to the human throat region,and snoring signals were recorded.A classification model was designed employing the convolutional neural network(CNN)model.Efforts have been laid to differentiate between normal and abnormal snores,which could help the patient with screening and early disease detection,contributing to self-powered healthcare applications.
基金supported by a Korea Medical Device Development Fund grant funded by the Korea government(the Ministry of Science and ICT,the Ministry of Trade,Industry and Energy,the Ministry of Health&Welfare,the Ministry of Food and Drug Safety)(Project Number:1711135031,KMDF_PR_20200901_0158-05).
文摘Surface electromyography(sEMG)sensors play a critical role in diagnosing muscle conditions and enabling prosthetic device control,especially for lower extremity robotic legs.However,challenges arise when utilizing such sensors on residual limbs within a silicon liner worn by amputees,where dynamic pressure,narrow space,and perspiration can negatively affect sensor performance.Existing commercial sEMG sensors and newly developed sensors are unsuitable due to size and thickness,or susceptible to damage in this environment.In this paper,our sEMG sensors are tailored for amputees wearing sockets,prioritizing breathability,durability,and reliable recording performance.By employing porous PDMS and Silbione substrates,our design achieves exceptional permeability and adhesive properties.The serpentine electrode pattern and design are optimized to improve stretchability,durability,and effective contact area,resulting in a higher signal-to-noise ratio(SNR)than conventional electrodes.Notably,our proposed sensors wirelessly enable to control of a robotic leg for amputees,demonstrating its practical feasibility and expecting to drive forward neuro-prosthetic control in the clinical research field near future.
基金supported by the Agency For Defense Development Grant Funded by the Korean Government(UI210008TD).
文摘The Fabry-Pérot interferometer,a fundamental component in optoelectronic systems,offers interesting applications such as sensors,lasers,and filters.In this work,we show a tunable Fabry-Pérot cavity consisting of tunable Sagnac loop reflectors(SLRs)and phase shifters based on electrostatic microelectromechanical(MEMS)actuator.The fabrication process of the device is compatible with the standard wafer-level silicon photonics fabrication processes.This electrostatic actuation mechanism provides well-balanced,scalable pathways for efficient tuning methodologies.The extinction ratio of the continuously tunable SLRs’reflectivity is larger than 20 dB.Full 2πphase shifting is achieved,and response times of all the components are less than 25μs.Both actuators have extremely low static power,measuring under 20 fW and the energy needed for tuning is both below 20 pJ.
