Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive prop...Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive properties for sensor and other applications. Protocols for 3-D self-assembly that can be scaled up for mass production on a large up to tonnage)scale, while preserving morphological features on a small (down to nanometer)scale,are needed to allow for widespread use of 3-D nanostructures in advanced devices.However,these often conflicting requirements of scalability and precision pose a difficult challenge for synthetic (man-made)processing routes.展开更多
The accumulation of heavy metals in mushrooms has presented a significant risk to human health,underscoring the importance of devising a portable and cost-effective method for detecting heavy metals.Thus,we have devel...The accumulation of heavy metals in mushrooms has presented a significant risk to human health,underscoring the importance of devising a portable and cost-effective method for detecting heavy metals.Thus,we have developed an electrochemical sensor based on 3-dimensional highly reduced graphene oxide(3D-HRGO)in conjunction with Fe_(3)O_(4)nanoparticles,enabling the simultaneous quantification of Cd^(2+),Pb^(2+),Cu^(2+),and Hg^(2+).The 3D-HRGO/Fe_(3)O_(4)nano-particles material prepared in this study was characterized and confirmed by multiple techniques,then dispersed in a simple and environmental dispersant,consist of 75%ethanol and 0.1%Nafion,and coating on a glass carbon electrode(GCE)to preparing a 3D-HRGO/Fe_(3)O_(4)/GCE sensor.The limit of detection(LOD)of 3D-HRGO/Fe_(3)O_(4)/GCE sensor for Cd^(2+),Pb^(2+),Cu^(2+),and Hg^(2+)in simultaneous detection were 0.2,0.6,0.6,and 0.9μg/L,respectively.The sensor demonstrates exceptional stability,reproducibility,anti-interference,and recovery rate.Furthermore,the electrochemical sensor was employed to detect heavy metals in actual mushrooms and validated through conventional methodologies.This study represents the pioneering utilization of 3D-HRGO/Fe_(3)O_(4)as a foundational material for an electrochemical sensor capable of simultaneous detection of multiple metals,thereby advancing the progress of on-site and expeditious detection techniques.展开更多
yb^3＋：Er^3＋ co-doped oxy-fluoride ceramics glass has been prepared. The mechanism of up-conversion emissions about Er^3＋ was discussed, and the temperature properties of green up-conversion fluorescence between 30...yb^3＋：Er^3＋ co-doped oxy-fluoride ceramics glass has been prepared. The mechanism of up-conversion emissions about Er^3＋ was discussed, and the temperature properties of green up-conversion fluorescence between 303 and 823 K were investigated. The results show that the sensitivity of this sample reaches its maximum value, about 0.0047 K^-1, when the temperature is 383 K, indicating that this kind of sample can be used as high temperature and high sensitivity optical temperature sensor.展开更多
Pure and Er-doped In 2O 3 nanotubes were systematically fabricated by using a single nozzle eletrospinning method followed by calcination.The as-synthesized nanotubes were characterized by scanning electron microscopy...Pure and Er-doped In 2O 3 nanotubes were systematically fabricated by using a single nozzle eletrospinning method followed by calcination.The as-synthesized nanotubes were characterized by scanning electron microscopy（SEM）,energy-dispersive X-ray（EDX） spectrometry and X-ray powder diffraction（XRD）.Compared with pure In 2O 3 nanotubes,Er-doped In 2O 3 nanotubes exhibit improved formaldehyde sensing properties at 260 ℃.The response of Er-doped In 2O 3 nanotubes to 20 ppm formaldehyde is about 12,which is 4 times larger than that of pure In 2O 3 nanotubes.The response and recovery times of Er-doped In 2O 3 nanotubes to 20 ppm formaldehyde are about 5 and 38 s,respectively.Furthermore,the response of Er-doped In 2O 3 nanotubes to 100 ppb formaldehyde is 2.19.展开更多
Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework n...Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework named the Formation Interfered Fluid Dynamical System(FIFDS) with Moderate Evasive Maneuver Strategy(MEMS) is proposed in this study.First, the UAV formation collision avoidance problem including quantifiable performance indexes is formulated. Second, inspired by the phenomenon of fluids continuously flowing while bypassing objects, the FIFDS for multiple UAVs is presented, which contains a Parallel Streamline Tracking(PST) method for formation keeping and the traditional IFDS for collision avoidance. Third, to rationally balance flight safety and collision avoidance cost, MEMS is proposed to generate moderate evasive maneuvers that match up with collision risks. Comprehensively containing the time and distance safety information, the 3-D dynamic collision regions are modeled for collision prediction. Then, the moderate evasive maneuver principle is refined, which provides criterions of the maneuver amplitude and direction. On this basis, an analytical parameter mapping mechanism is designed to online optimize IFDS parameters. Finally, the performance of the proposed method is validated by comparative simulation results and real flight experiments using fixed-wing UAVs.展开更多
Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to ...Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective,and controllable method. Herein, we reported the preparation of the Al-doped Zn O(AZO)/WO_(3) heterostructure films by directly depositing the AZO coating onto the WO_(3) coating using a strategy of magnetron sputtering. The AZO/WO_(3) heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO_(3) heterostructure films-based gas sensors exhibited excellent isopropanolsensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO_(3) heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness,and the construction of the heterostructure between the AZO and WO_(3) coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.展开更多
Listeria monocytogenes(LM)is a dangerous foodborne pathogen for humans.One emerging and validated method of indirectly assessing LM in food is detecting 3-hydroxy-2-butanone(3H2B)gas.In this study,the synthesis of 3-(...Listeria monocytogenes(LM)is a dangerous foodborne pathogen for humans.One emerging and validated method of indirectly assessing LM in food is detecting 3-hydroxy-2-butanone(3H2B)gas.In this study,the synthesis of 3-(2-aminoethylamino)propyltrimethoxysilane(AAPTMS)functionalized hierarchical hollow TiO_(2)nanospheres was achieved via precise controlling of solvothermal reaction temperature and post-grafting route.The sensors based on as-prepared materials exhibited excellent sensitivity(480 Hz@50 ppm),low detection limit(100 ppb),and outstanding selectivity.Moreover,the evaluation of LM with high sensitivity and specificity was achieved using the sensors.Such stable three-dimensional spheres,whose distinctive hierarchical and hollow nanostructure simultaneously improved both sensitivity and response/recovery speed dramatically,were spontaneously assembled by nanosheets.Meanwhile,the moderate loadings of AAPTMS significantly improved the selectivity of sensors.Then,the gas-sensing mechanism was explored by utilizing thermodynamic investigation,Gaussian 16 software,and in situ diffuse reflectance infrared transform spectroscopy,illustrating the weak chemisorption between the-NHgroup and 3H2B molecules.These portable sensors are promising for real-time assessment of LM at room temperature,which will make a magnificent contribution to food safety.展开更多
Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,...Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO_(2)(p-n junction)and Ti_(3)C_(2)T_(x) MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO_(2),forming in-situ p-n junctions on the surface of Sn O.The hamburger-like SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensor exhibited improved acetone gas sensing response of 12.1(R_(g)/R_(a))at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti_(3)C_(2)T_(x) and pristine SnO-SnO_(2),respectively.Moreover,it expressed a short recovery time(9 s)and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti_(3)C_(2)T_(x) nanosheets,acting as a hole accumulation layer(HALs)between Ti_(3)C_(2)T_(x) and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti_(3)C_(2)T_(x) MXene in SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensors was discussed in detail.展开更多
MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X...MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X-Ray, endoscopy. It is a key for us to locate and track the position of a MEMS capsule in clinical applications. To solve this problem, we implemented a magnetic sensor module based on the scalar form of the magnetic dipole model,which was designed with very small size （5.2 ＊ 2. 1 ＊ 1.2 em） and easy to assemble to satisfy the system requirement. Here we discuss in detail the principle of magnetic dipole model, rules of selecting sensor and functions of the module. Some trials are established to test the characteristic of the module. The results of the Cm experiment demonstrates that the module follows the rules of the new magnetic dipole model form.展开更多
This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollu...This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.展开更多
Nighttime navigation faces challenges from limited data and interference,especially when satellite signals are unavailable.Leveraging lunar polarized light,polarization navigation offers a promising solution for night...Nighttime navigation faces challenges from limited data and interference,especially when satellite signals are unavailable.Leveraging lunar polarized light,polarization navigation offers a promising solution for nighttime autonomous navigation.Current algorithms,however,are limited by the requirement for known horizontal attitudes,restricting applications.This study introduces an autonomous 3-D attitude determination method to overcome this limitation.Our approach utilizes the Angle of Polarization(AOP)at night to extract neutral points from the AOP pattern.This allows for the calculation of polarization meridian plane information for attitude determination.Subsequently,we present an optimized Polarization TRIAD(Pol-TRIAD)algorithm to acquire the 3-D attitude.The proposed method outperforms the existing approaches in outdoor experiments by achieving lower Root Mean Square Error(RMSE).For one baseline attitude,it improves pitch by 31.7%,roll by 21.7%,and yaw by 2.6%,while for the attitude with a larger tilt angle,the improvements are 64.4%,30.4%,and 9.1%,respectively.展开更多
Herein,a modified screen printed carbon electrode(SPCE)based on a composite material,graphene oxide-gold nanoparticles(GO-AuNPs),and poly(3-aminobenzoic acid)(P3ABA)for the detection of paraquat(PQ)is introduced.The m...Herein,a modified screen printed carbon electrode(SPCE)based on a composite material,graphene oxide-gold nanoparticles(GO-AuNPs),and poly(3-aminobenzoic acid)(P3ABA)for the detection of paraquat(PQ)is introduced.The modified electrode was fabricated by drop casting of the GO-AuNPs,followed by electropolymerization of 3-aminobenzoic acid to achieve SPCE/GO-AuNPs/P3ABA.The morphology and microstructural characteristics of the modified electrodes were revealed by scanning electron microscopy(SEM)for each step of modification.The composite GO-AuNPs can provide high surface area and enhance electroconductivity of the electrode.In addition,the presence of negatively charged P3ABA notably improved PQ adsorption and electron transfer rate,which stimulate redox reaction on the modified electrode,thus improving the sensitivity of PQ analysis.The SPCE/GOAuNPs/P3ABA offered a wide linear range of PQ determination(10^(−9)-10^(−4) mol/L)and low limit of detection(LOD)of 0.45×10^(−9) mol/L or 0.116μg/L,which is far below international safety regulations.The modified electrode showed minimum interference effect with percent recovery ranging from 96.5%to 116.1%after addition of other herbicides,pesticides,metal ions,and additives.The stability of the SPCE/GO-AuNPs/P3ABA was evaluated,and the results indicated negligible changes in the detection signal over 9 weeks.Moreover,this modified electrode was successfully implemented for PQ analysis in both natural and tapped water with high accuracy.展开更多
Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages...Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages,which hampers effective communication for non-standard language people.Here,we prepare an ultralight Ti_(3)C_(2)T_(x)MXene/chitosan/polyvinylidene difluoride composite aerogel with a detection range of 6.25 Pa-1200 k Pa,rapid response/recovery time,and low hysteresis(13.69%).The wearable aerogel pressure sensor can detect speech information through the throat muscle vibrations without any interference,allowing for accurate recognition of six dialects(96.2%accuracy)and seven different words(96.6%accuracy)with the assistance of convolutional neural networks.This work represents a significant step forward in silent speech recognition for human–machine interaction and physiological signal monitoring.展开更多
The rapid progress of wireless communication and the availability of many small-sized, light-weighted and low-cost communication and computing devices nowadays have greatly impacted the development of wireless sensor ...The rapid progress of wireless communication and the availability of many small-sized, light-weighted and low-cost communication and computing devices nowadays have greatly impacted the development of wireless sensor network. Localization using sensor network has attracted much attention for its comparable low-cost and potential use with mon- itoring and targeting purposes in real and hostile application scenarios. Currently, there are many available approaches to locating persons/things based on global positioning system (GPS) and radio-frequency identification (RFID) technologies. However, in some application scenario, e.g., disaster rescue application, such localization devices may be damaged and may not provide the location information of the survivors. The main goal of this paper is to design and develop a robust localization technique for human existence detection in case of disasters such as earthquake or fire. In this paper, we propose a 3-D localization technique based on the hop-count data collected from sensor anchors to estimate the location of the activated sensor mote in 3-D coordination. Our algorithm incorporates two salient features, cubic-based output and event-triggering mechanism, to guarantee both improved accuracy and power efficiency. Both simulation and experimental results indicate that the proposed algorithm can improve the localization precision of the human existence and work well in real environment.展开更多
Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti...Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.展开更多
文摘Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive properties for sensor and other applications. Protocols for 3-D self-assembly that can be scaled up for mass production on a large up to tonnage)scale, while preserving morphological features on a small (down to nanometer)scale,are needed to allow for widespread use of 3-D nanostructures in advanced devices.However,these often conflicting requirements of scalability and precision pose a difficult challenge for synthetic (man-made)processing routes.
基金the National Natural Science Foundation of China(31972173)the Program for Science&Technology Innovation Talents of Hunan Province(2022SK2100,2021RC4032,and 2019TP1029)the Ministry of Agriculture of the People’s Republic of China(GJFP2021)。
文摘The accumulation of heavy metals in mushrooms has presented a significant risk to human health,underscoring the importance of devising a portable and cost-effective method for detecting heavy metals.Thus,we have developed an electrochemical sensor based on 3-dimensional highly reduced graphene oxide(3D-HRGO)in conjunction with Fe_(3)O_(4)nanoparticles,enabling the simultaneous quantification of Cd^(2+),Pb^(2+),Cu^(2+),and Hg^(2+).The 3D-HRGO/Fe_(3)O_(4)nano-particles material prepared in this study was characterized and confirmed by multiple techniques,then dispersed in a simple and environmental dispersant,consist of 75%ethanol and 0.1%Nafion,and coating on a glass carbon electrode(GCE)to preparing a 3D-HRGO/Fe_(3)O_(4)/GCE sensor.The limit of detection(LOD)of 3D-HRGO/Fe_(3)O_(4)/GCE sensor for Cd^(2+),Pb^(2+),Cu^(2+),and Hg^(2+)in simultaneous detection were 0.2,0.6,0.6,and 0.9μg/L,respectively.The sensor demonstrates exceptional stability,reproducibility,anti-interference,and recovery rate.Furthermore,the electrochemical sensor was employed to detect heavy metals in actual mushrooms and validated through conventional methodologies.This study represents the pioneering utilization of 3D-HRGO/Fe_(3)O_(4)as a foundational material for an electrochemical sensor capable of simultaneous detection of multiple metals,thereby advancing the progress of on-site and expeditious detection techniques.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10804015 )the Science Foundation of the Education Department of Liaoning Province of China (Grant No. 2009A417)
文摘yb^3＋：Er^3＋ co-doped oxy-fluoride ceramics glass has been prepared. The mechanism of up-conversion emissions about Er^3＋ was discussed, and the temperature properties of green up-conversion fluorescence between 303 and 823 K were investigated. The results show that the sensitivity of this sample reaches its maximum value, about 0.0047 K^-1, when the temperature is 383 K, indicating that this kind of sample can be used as high temperature and high sensitivity optical temperature sensor.
基金supported by the Jilin Provincial Science and Technology Department (No.20140204027GX)
文摘Pure and Er-doped In 2O 3 nanotubes were systematically fabricated by using a single nozzle eletrospinning method followed by calcination.The as-synthesized nanotubes were characterized by scanning electron microscopy（SEM）,energy-dispersive X-ray（EDX） spectrometry and X-ray powder diffraction（XRD）.Compared with pure In 2O 3 nanotubes,Er-doped In 2O 3 nanotubes exhibit improved formaldehyde sensing properties at 260 ℃.The response of Er-doped In 2O 3 nanotubes to 20 ppm formaldehyde is about 12,which is 4 times larger than that of pure In 2O 3 nanotubes.The response and recovery times of Er-doped In 2O 3 nanotubes to 20 ppm formaldehyde are about 5 and 38 s,respectively.Furthermore,the response of Er-doped In 2O 3 nanotubes to 100 ppb formaldehyde is 2.19.
基金supported in part by the National Natural Science Foundations of China(Nos.61175084,61673042 and 62203046)the China Postdoctoral Science Foundation(No.2022M713006).
文摘Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework named the Formation Interfered Fluid Dynamical System(FIFDS) with Moderate Evasive Maneuver Strategy(MEMS) is proposed in this study.First, the UAV formation collision avoidance problem including quantifiable performance indexes is formulated. Second, inspired by the phenomenon of fluids continuously flowing while bypassing objects, the FIFDS for multiple UAVs is presented, which contains a Parallel Streamline Tracking(PST) method for formation keeping and the traditional IFDS for collision avoidance. Third, to rationally balance flight safety and collision avoidance cost, MEMS is proposed to generate moderate evasive maneuvers that match up with collision risks. Comprehensively containing the time and distance safety information, the 3-D dynamic collision regions are modeled for collision prediction. Then, the moderate evasive maneuver principle is refined, which provides criterions of the maneuver amplitude and direction. On this basis, an analytical parameter mapping mechanism is designed to online optimize IFDS parameters. Finally, the performance of the proposed method is validated by comparative simulation results and real flight experiments using fixed-wing UAVs.
基金financially supported by the National Natural Science Foundation of China (Nos.52172094 and 22209105)Shanghai Municipal Natural Science Foundation (No.21ZR1426700)the “Shuguang” Program of Shanghai Education Commission (No.19SG46)。
文摘Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective,and controllable method. Herein, we reported the preparation of the Al-doped Zn O(AZO)/WO_(3) heterostructure films by directly depositing the AZO coating onto the WO_(3) coating using a strategy of magnetron sputtering. The AZO/WO_(3) heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO_(3) heterostructure films-based gas sensors exhibited excellent isopropanolsensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO_(3) heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness,and the construction of the heterostructure between the AZO and WO_(3) coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.
基金supported by the National Natural Science Foundation of China(No.32272399)the Shanghai Natural Science Foundation(No.21ZR1427500).
文摘Listeria monocytogenes(LM)is a dangerous foodborne pathogen for humans.One emerging and validated method of indirectly assessing LM in food is detecting 3-hydroxy-2-butanone(3H2B)gas.In this study,the synthesis of 3-(2-aminoethylamino)propyltrimethoxysilane(AAPTMS)functionalized hierarchical hollow TiO_(2)nanospheres was achieved via precise controlling of solvothermal reaction temperature and post-grafting route.The sensors based on as-prepared materials exhibited excellent sensitivity(480 Hz@50 ppm),low detection limit(100 ppb),and outstanding selectivity.Moreover,the evaluation of LM with high sensitivity and specificity was achieved using the sensors.Such stable three-dimensional spheres,whose distinctive hierarchical and hollow nanostructure simultaneously improved both sensitivity and response/recovery speed dramatically,were spontaneously assembled by nanosheets.Meanwhile,the moderate loadings of AAPTMS significantly improved the selectivity of sensors.Then,the gas-sensing mechanism was explored by utilizing thermodynamic investigation,Gaussian 16 software,and in situ diffuse reflectance infrared transform spectroscopy,illustrating the weak chemisorption between the-NHgroup and 3H2B molecules.These portable sensors are promising for real-time assessment of LM at room temperature,which will make a magnificent contribution to food safety.
基金supported financially by the National Natural Science Foundation of China(Nos.,51572158 and 51972200)the Graduate Innovation Fund of Shaanxi University of Science&Technology+2 种基金funded by the Japan Society for the Promotion of Science(JSPS)Grant-in-Aid for the Scientific Research(KAKENHI Nos.20H00297 and Innovative Area“Mixed Anion”(No.16H06439))the Nippon Sheet Glass Foundation for Materials Science and Engineeringby the Dynamic Alliance for Open Innovations Bridging Human,Environment and Materials,the Cooperative Research Program of“Network Joint Research Center for Materials and Devices”。
文摘Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO_(2)(p-n junction)and Ti_(3)C_(2)T_(x) MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO_(2),forming in-situ p-n junctions on the surface of Sn O.The hamburger-like SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensor exhibited improved acetone gas sensing response of 12.1(R_(g)/R_(a))at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti_(3)C_(2)T_(x) and pristine SnO-SnO_(2),respectively.Moreover,it expressed a short recovery time(9 s)and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti_(3)C_(2)T_(x) nanosheets,acting as a hole accumulation layer(HALs)between Ti_(3)C_(2)T_(x) and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti_(3)C_(2)T_(x) MXene in SnO-SnO_(2)/Ti_(3)C_(2)T_(x) sensors was discussed in detail.
文摘MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X-Ray, endoscopy. It is a key for us to locate and track the position of a MEMS capsule in clinical applications. To solve this problem, we implemented a magnetic sensor module based on the scalar form of the magnetic dipole model,which was designed with very small size （5.2 ＊ 2. 1 ＊ 1.2 em） and easy to assemble to satisfy the system requirement. Here we discuss in detail the principle of magnetic dipole model, rules of selecting sensor and functions of the module. Some trials are established to test the characteristic of the module. The results of the Cm experiment demonstrates that the module follows the rules of the new magnetic dipole model form.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(RS-202300243390 and 2020R1A5A1018052)supported by the Basic Science Research Program through the National Research Foundation of Korea,funded by the Ministry of Education(2022R1A3B1078163)supported by the Technology Innovation Program(Publicprivate joint investment semiconductor R&D program[K-CHIPS])to foster high-quality human resources(RS-2023-00235484)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)(1415187770)。
文摘This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.
基金supported in part by the National Key Research and Development Program of China(Nos.2020YFA0711200,2022YFB4701301)in part by the Defense Industrial Technology Development Program,China(No.JCKY2021601B016)+1 种基金in part by the Fundamental Research Funds for the Central Universities,China(No.YWF-23-JC-07)in part by the National Natural Science Foundation of China(No.62425302)。
文摘Nighttime navigation faces challenges from limited data and interference,especially when satellite signals are unavailable.Leveraging lunar polarized light,polarization navigation offers a promising solution for nighttime autonomous navigation.Current algorithms,however,are limited by the requirement for known horizontal attitudes,restricting applications.This study introduces an autonomous 3-D attitude determination method to overcome this limitation.Our approach utilizes the Angle of Polarization(AOP)at night to extract neutral points from the AOP pattern.This allows for the calculation of polarization meridian plane information for attitude determination.Subsequently,we present an optimized Polarization TRIAD(Pol-TRIAD)algorithm to acquire the 3-D attitude.The proposed method outperforms the existing approaches in outdoor experiments by achieving lower Root Mean Square Error(RMSE).For one baseline attitude,it improves pitch by 31.7%,roll by 21.7%,and yaw by 2.6%,while for the attitude with a larger tilt angle,the improvements are 64.4%,30.4%,and 9.1%,respectively.
基金supported by the ProgramManagement Unit on Area Based Development (PMUA),Thailand (No.4594393)the National Science and Technology Development Agency (NSTDA),Thailand (No.P2250367).
文摘Herein,a modified screen printed carbon electrode(SPCE)based on a composite material,graphene oxide-gold nanoparticles(GO-AuNPs),and poly(3-aminobenzoic acid)(P3ABA)for the detection of paraquat(PQ)is introduced.The modified electrode was fabricated by drop casting of the GO-AuNPs,followed by electropolymerization of 3-aminobenzoic acid to achieve SPCE/GO-AuNPs/P3ABA.The morphology and microstructural characteristics of the modified electrodes were revealed by scanning electron microscopy(SEM)for each step of modification.The composite GO-AuNPs can provide high surface area and enhance electroconductivity of the electrode.In addition,the presence of negatively charged P3ABA notably improved PQ adsorption and electron transfer rate,which stimulate redox reaction on the modified electrode,thus improving the sensitivity of PQ analysis.The SPCE/GOAuNPs/P3ABA offered a wide linear range of PQ determination(10^(−9)-10^(−4) mol/L)and low limit of detection(LOD)of 0.45×10^(−9) mol/L or 0.116μg/L,which is far below international safety regulations.The modified electrode showed minimum interference effect with percent recovery ranging from 96.5%to 116.1%after addition of other herbicides,pesticides,metal ions,and additives.The stability of the SPCE/GO-AuNPs/P3ABA was evaluated,and the results indicated negligible changes in the detection signal over 9 weeks.Moreover,this modified electrode was successfully implemented for PQ analysis in both natural and tapped water with high accuracy.
基金supported by the National Nature Science Foundation of China(No.62122030,62333008,62371205,52103208)National Key Research and Development Program of China(No.2021YFB3201300)+1 种基金Application and Basic Research of Jilin Province(20130102010 JC)Fundamental Research Funds for the Central Universities,Jilin Provincial Science and Technology Development Program(20230101072JC)。
文摘Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages,which hampers effective communication for non-standard language people.Here,we prepare an ultralight Ti_(3)C_(2)T_(x)MXene/chitosan/polyvinylidene difluoride composite aerogel with a detection range of 6.25 Pa-1200 k Pa,rapid response/recovery time,and low hysteresis(13.69%).The wearable aerogel pressure sensor can detect speech information through the throat muscle vibrations without any interference,allowing for accurate recognition of six dialects(96.2%accuracy)and seven different words(96.6%accuracy)with the assistance of convolutional neural networks.This work represents a significant step forward in silent speech recognition for human–machine interaction and physiological signal monitoring.
文摘The rapid progress of wireless communication and the availability of many small-sized, light-weighted and low-cost communication and computing devices nowadays have greatly impacted the development of wireless sensor network. Localization using sensor network has attracted much attention for its comparable low-cost and potential use with mon- itoring and targeting purposes in real and hostile application scenarios. Currently, there are many available approaches to locating persons/things based on global positioning system (GPS) and radio-frequency identification (RFID) technologies. However, in some application scenario, e.g., disaster rescue application, such localization devices may be damaged and may not provide the location information of the survivors. The main goal of this paper is to design and develop a robust localization technique for human existence detection in case of disasters such as earthquake or fire. In this paper, we propose a 3-D localization technique based on the hop-count data collected from sensor anchors to estimate the location of the activated sensor mote in 3-D coordination. Our algorithm incorporates two salient features, cubic-based output and event-triggering mechanism, to guarantee both improved accuracy and power efficiency. Both simulation and experimental results indicate that the proposed algorithm can improve the localization precision of the human existence and work well in real environment.
基金the National Key R&D Program of China(No.2023YFB3210102).
文摘Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.
