High-sensitivity sensors represent a critical frontier in modern sensing technology,driving innovations across fields such as biomedical monitoring,precision instrumentation,environmental detection,and indus-trial aut...High-sensitivity sensors represent a critical frontier in modern sensing technology,driving innovations across fields such as biomedical monitoring,precision instrumentation,environmental detection,and indus-trial automation.As demands for accuracy,miniaturization,and reliability continue to grow,developing novel sensor architectures and functional materials has become essential to achieving enhanced performance under extreme or complex conditions.展开更多
A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electro...A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electrons in a metal are resonated with photons.The structural parameters are fine-tuned and the sensing performance of the sensor is studied.The results show that the maximum spectral sensitivity reaches 18 000 nm/RIU in the refractive index range of 1.24—1.32,and the maximum resolution is 5.56×10^(-6) RIU.The novel structure with high sensitivity and low refractive index provides a new perspective for fluid density detection.展开更多
Pressure sensors are essential for a wide range of applica-tions,including health monitoring,industrial diagnostics,etc.However,achieving both high sensitivity and mechanical ability to withstand high pressure in a si...Pressure sensors are essential for a wide range of applica-tions,including health monitoring,industrial diagnostics,etc.However,achieving both high sensitivity and mechanical ability to withstand high pressure in a single material remains a significant challenge.This study introduces a high-performance cellulose hydrogel inspired by the biomi-metic layered porous structure of human skin.The hydrogel features a novel design composed of a soft layer with large macropores and a hard layer with small micropores,each of which contribute uniquely to its pressure-sensing capabilities.The macropores in the soft part facilitate significant deforma-tion and charge accumulation,providing exceptional sensitivity to low pressures.In contrast,the microporous structure in the hard part enhances pressure range,ensuring support under high pressures and preventing structural failure.The performance of hydrogel is further optimized through ion introduction,which improves its conductivity,and as well the sensitivity.The sensor demonstrated a high sensitivity of 1622kPa^(-1),a detec-tion range up to 160 kPa,excellent conductivity of 4.01 Sm^(-1),rapid response time of 33 ms,and a low detection limit of 1.6 Pa,outperforming most existing cellulose-based sensors.This innovative hierarchically porous architecture not only enhances the pressure-sensing performance but also offers a simple and effective approach for utilizing natural polymers in sensing technologies.The cellulose hydrogel demonstrates sig-nificant potential in both health monitoring and industrial applications,providing a sensitive,durable,and versatile solution for pressure sensing.展开更多
High-temperature thin-film strain sensors are advanced technological devices for monitoring stress and strain in extreme environments,but the coupling of temperature and strain at high temperature is a challenge for t...High-temperature thin-film strain sensors are advanced technological devices for monitoring stress and strain in extreme environments,but the coupling of temperature and strain at high temperature is a challenge for their use.Here,this issue is addressed by creating a composite ink that combines Pb_(2)Ru_(2)O_(6) and TiB_(2) using polysilazane(PSZ)as a binder.After direct writing and annealing the PSZ/Pb_(2)Ru_(2)O_(6)/TiB_(2) film at 800℃ in air,the resulting thin film exhibits a low temperature coefficient of resistance(TCR)of only 281 ppm/℃ over a wide temperature range from 100℃ to 700℃,while also demonstrating high sensitivity with a gauge factor approaching 19.8.This exceptional performance is attributed to the intrinsic properties of Pb_(2)Ru_(2)O_(6),which has positive TCR at high temperature,and TiB2,which has negative TCR at high temperature.Combining these materials reduces the overall TCR of the film.Tests showed that the PSZ/Pb_(2)Ru_(2)O_(6)/TiB_(2) film maintains stable strain responses and significant signal output even under varying temperature.These findings provide valuable insights for developing high-temperature strain sensors with low TCR and high sensitivity,highlighting their potential for applications in high-temperature strain measurements.展开更多
Electronic skin has showcased superior sensing capabilities inspired from human skin.However,most preceding studies focused on the dermis of the skin rather than the epidermis.In particular,the pseudo-porous structura...Electronic skin has showcased superior sensing capabilities inspired from human skin.However,most preceding studies focused on the dermis of the skin rather than the epidermis.In particular,the pseudo-porous structural domain of the epidermis increases the skin's tolerance while ensuring its susceptibility to touch.Yet,most endeavors on the porous structures failed to replicate the superior sensing performance of skin-like counterparts in terms of sensitivity and/or detection range.Stimulated by the strategy that the epidermis of the skin absorbs energy while producing ionic conduction to the nerves,this work initiatively introduced an easy-to-produce,and low-cost pressure sensor based on ionic-gel foam,and achieved a high sensitivity(2893 kPa^(-1))within a wide pressure range(up to~1 MPa),which ranked among the best cases thus far.Moreover,the factors affecting the sensor performance were explored while the sensing principles were enriched.Inspiringly,the plantar pressure measurement by harnessing the as-prepared sensor unveiled an ultra-broad detection range(100 Pa-1 MPa),thus delivering a huge application potential in the field of robot and health monitoring.展开更多
Flexible piezoresistive sensors based on biomimetic microstructures are prospective for broad application in motion monitoring.However,the design and preparation processes of most biomimetic microstructures in the exi...Flexible piezoresistive sensors based on biomimetic microstructures are prospective for broad application in motion monitoring.However,the design and preparation processes of most biomimetic microstructures in the existing studies are complicated,and there are few studies on pore size control.Herein,the porous structure of human bones was used as a biomimetic prototype,and optimally designed by creating a theoretical equivalent sensor model and a finite element model.Soluble raw materials such as sugar and salt in different particle sizes were pressed into porous templates.Based on the template method,porous structures in different pore sizes were prepared using polydimethylsiloxane(PDMS)polymer as the substrate.On this basis,graphene oxide conductive coating was prepared with the modified Hummers method and then deposited via dip coating onto the substrate.Finally,a PDMS-based porous structure biomimetic flexible piezoresistive sensor was developed.Mechanically,the deformation of the sensor under the same load increased with the pore size rising from 0.3 to 1.5 mm.Electrically,the resistance rang of the sensor was enlarged as the pore size rose.The resistance variation rates of samples with pore sizes of 0.3,1.0,and 1.5 mm at approximately the 200th cycle were 63%,79%,and 81%,respectively;at the 500th cycle,these values were 63%,77%,and 79%;and at the 1000th cycle,they stabilized at 63%,74%,and 76%.These results indicate that the fabricated sensor exhibits high stability and fatigue resistance.At the pressure of 0–25 kPa,the sensitivity rose from 0.0688 to 0.1260 kPa−1,and the performance was enhanced by 83%.After 1,000 cycles of compression testing,the signal output was stable,and no damage was caused to the substrate.Further application tests showed the biomimetic sensor accurately and effectively identified human joint motions and gestures,and has potential application value in human motion monitoring.展开更多
High-performance flexible pressure sensors have garnered significant attention in fields such as wearable electronics and human-machine interfaces.However,the development of flexible pressure sensors that simultaneous...High-performance flexible pressure sensors have garnered significant attention in fields such as wearable electronics and human-machine interfaces.However,the development of flexible pressure sensors that simultaneously achieve high sensitivity,a wide detection range,and good mechanical stability remains a challenge.In this paper,we propose a flexible piezoresistive pressure sensor based on a Ti_(3)C_(2)Tx(MXene)/polyethylene oxide(PEO)composite nanofiber membrane(CNM).The sensor,utilizing MXene(0.4 wt%)/PEO(5 wt%),exhibits high sensitivity(44.34 kPa^(−1)at 0−50 kPa,12.99 kPa^(−1)at 50−500 kPa)and can reliably monitor physiological signals and other subtle cues.Moreover,the sensor features a wide detection range(0−500 kPa),fast response and recovery time(~150/45 ms),and excellent mechanical stability(over 10000 pressure cycles at maximum load).Through an MXene/PEO sensor array,we demonstrate its applications in human physiological signal monitoring,providing a reliable way to expand the application of MXene-based flexible pressure sensors.展开更多
Background The data on the prognostic values of high sensitivity C-reactive protein （hsCRP） levels in patients with advanced symp-tomatic heart failure （HF） receiving cardiac resynchronization therapy （CRT） are ...Background The data on the prognostic values of high sensitivity C-reactive protein （hsCRP） levels in patients with advanced symp-tomatic heart failure （HF） receiving cardiac resynchronization therapy （CRT） are scarce. The aim of present study was to investigate the association of serum hsCRP levels with left ventricle reverse remodeling after six months of CRT as well as long-term outcome. Methods A total of 232 CRT patients were included. The assessment of hsCRP values, clinical status and echocardiographic data were performed at baseline and after six months of CRT. Long-term follow-up included all-cause mortality and hospitalizations for HF. Results During the mean follow-up periods of 31.3 ± 31.5 months, elevated hsCRP （〉3 mg/L） prior to CRT was associated with a significant 2.39-fold increase （P=0.006） in the risk of death or HF hospitalizations. At 6-month follow-up, patients who responded to CRT showed significant reductions or maintained low in hsCRP levels （–0.5 ± 4.1 mg/L reduction） compared with non-responders （1.7 ± 6.1 mg/L increase, P=0.018）. Com-pared with patients in whom 6-month hsCRP levels were reduced or remained low, patients in whom 6-month hsCRP levels were increased or maintained high experienced a significantly higher risk of subsequent death or HF hospitalizations （Log-rank P〈0.001）. The echocardio-graphic improvement was also better among patients in whom 6-month hsCRP levels were reduced or remained low compared to those in whom 6-month hsCRP levels were raised or maintained high. Conclusions Our findings demonstrated that measurement of baseline and follow-up hsCRP levels may be useful as prognostic markers for timely potential risk stratification and subsequent appropriate treatment strategies in patients with advanced HF undergoing CRT.展开更多
Thermal sensing and imaging in the physiological temperature range are of great importance for studying physiological processes and treating diseases. Metal-organic frameworks(MOFs) exhibit great promise for developin...Thermal sensing and imaging in the physiological temperature range are of great importance for studying physiological processes and treating diseases. Metal-organic frameworks(MOFs) exhibit great promise for developing luminescent thermometers due to their remarkable structural diversities and tunable luminescence properties. Here, we synthesized a series of luminescent mixed-lanthanide MOFs,EuTbBPT(x = 0.019, 0.058, 0.106; H3 BPT = biphenyl-3,4’,5-tricarboxylate acid) and adopted powder X-ray diffraction(PXRD), thermogravimetric analysis(TGA) and Fourier transform infrared(FT-IR) to characterize the resulting products. The temperature-dependent photoluminescence emission spectra were recorded to investigate their potential applications in physiological temperature readout. It is found that the intensity ratio of Tbto Euis linearly correlated with temperature and the relative sensitivity is higher than 1.5%/℃ over the entire physiological temperature range. Furthermore,the temperaturedependent luminescence color emission allows for visual colorimetric temperature measurements.Luminescence lifetime testing and triplet energy level measurement were further conducted to study the mechanism.展开更多
1 Introduction Inflammation is one of the main mechanisms in the pathogenesis of atherosclerosis,and the interest to the evaluation of inflammatory biomarkers in coronary artery disease(CAD)has been increasing over th...1 Introduction Inflammation is one of the main mechanisms in the pathogenesis of atherosclerosis,and the interest to the evaluation of inflammatory biomarkers in coronary artery disease(CAD)has been increasing over the last decade.[1,2]Destabilization of chronic artery plaques,which leads to acute coronary syndromes,has been associated with inflammatory status.[1,3]。展开更多
With the prosperous development of artificial intelligence,medical diagnosis and electronic skins,wearable electronic devices have drawn much attention in our daily life.Flexible pressure sensors based on carbon mater...With the prosperous development of artificial intelligence,medical diagnosis and electronic skins,wearable electronic devices have drawn much attention in our daily life.Flexible pressure sensors based on carbon materials with ultrahigh sensitivity,especially in a large pressure range regime are highly required in wearable applications.In this work,graphene membrane with a layer-by-layer structure has been successfully fabricated via a facile self-assembly and air-drying(SAAD)method.In the SAAD process,air-drying the self-assembled graphene hydrogels contributes to the uniform and compact layer structure in the obtained membranes.Owing to the excellent mechanical and electrical properties of graphene,the pressure sensor constructed by several layers of membranes exhibits high sensitivity(52.36 kPa……-1)and repeatability(short response and recovery time)in the loading pressure range of 0–50 kPa.Compared with most reported graphene-related pressure sensors,our device shows better sensitivity and wider applied pressure range.What’s more,we demonstrate it shows desired results in wearable applications for pulse monitoring,breathing detection as well as different intense motion recording such as walk,run and squat.It’s hoped that the facilely prepared layer-by-layer graphene membrane-based pressure sensors will have more potential to be used for smart wearable devices in the future.展开更多
Highly sensitive pressure sensors are often deployed in human-machine interaction area,touch screen and human motion detection.However,there are still great challenges to fabricating with high sensitivity pressure sen...Highly sensitive pressure sensors are often deployed in human-machine interaction area,touch screen and human motion detection.However,there are still great challenges to fabricating with high sensitivity pressure sensor with wide-range detection.Herein,we developed a new strategy to fabricate a highly sensitive pressure sensor using sandpaper and improve its detection range using a sacrificial template.It was the fthatirst time to combine microstructure processing with the sacrificial template method to fabricate pressure sensor.The microstructure of sandpaper endowed the sensor with high sensitivity,and the elastic substrate enhanced the sensor ability to resist high pressure without being damaged.The fabricated sensor device exhibits a superior sensitivity of 39.077 kPa-1in the range from 50 kPa to 110 kPa with a broad linear response.Remarkably,high pressure ceiling(<160 kPa) ensures that the sponge could be applied in different practical conditions to monitor a range of subtle human motions including finger,wrist bending,and pulse.For applications,the sensor device can not only detect the foot stepping behavior(0.7 MPa) but also produce an obvious response to an extremely slight paper(9 mg,~0.9 Pa).The successful preparation of this micro-structured elastic sponge material provided new ideas for exploring its potential applications in pressure sensors and flexible wearable electronic devices.展开更多
In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances i...In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances in terms of data channel coding which might result in a signal structure where the symbol duration is shorter than the pseudo code period. This can generate some difficulties in the DSSS signal acquisition due to the polarity inversion caused by the data modulation. To eliminate the influence due to polarity inversion, this paper proposes a novel acquisition algorithm based on the simultaneous search of the code phase, data phase and Doppler frequency. In the proposed algorithm the data phase is predicted and the correlation period for the coherent integration can be set equal to the symbol duration. Then non-coherent accumulation over different symbol is implemented in order to enhance the acquisition algorithm sensitivity; the interval of non-coherent accumulation is the least common multiple between the symbol duration and the pseudo code period. The algorithm proposed can largely minimize the SNR loss caused by data polarity inversion and enhance acquisition performance without a noticeable increase in hardware complexity. Theoretical analysis, simulation and measured results verify the validity of the algorithm.展开更多
We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the se...We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case.展开更多
Background Coronary artery disease(CAD)remains a leading cause of morbidity and mortality.Cytokines play a potential role in atherosclerosis pathogenesis and progression.We investigated the association between high se...Background Coronary artery disease(CAD)remains a leading cause of morbidity and mortality.Cytokines play a potential role in atherosclerosis pathogenesis and progression.We investigated the association between high sensitive C-reactive protein(hs CRP)and severity of CAD.Methods CAD patients were stratified according to hs CRP cut-off value into high levels hs CRP group(≥8.4 mg/L)and low levels hs CRP group(<8.4 mg/L).Severity of CAD was assessed according to artery stenosis degree and the number of vessel involved.Statistical analysis was performed using Statistical Package for the Social Sciences(SPSS,version 23.0).Results The mean age was 60.3±11.0 years.The level of hs CRP was increased and ranged from 0.2 to 1020.0 mg/L.Biochemical risk factors and severity of CAD didn’t show significant differences between the two groups.In multivariate linear analysis,cardiac troponin I(c Tn I)and serum amyloid A(SAA)were predictors of hs CRP.As shown in receiver operating characteristic(ROC)curve analysis performed in patients with ST-segment elevation myocardial infarction(STEMI)and compared to myonecrosis biomarkers,hs CRP(area under the curve(AUC):0.905;95%CI:0.844-0.966;P<0.001)could be a powerful predictor marker in evaluating the infarct size after myocardial infarction but not better than c Tn I.Conclusions Hs CRP levels were not associated with the severity of CAD but could be useful in the evaluation of myocardial necrosis in patients with STEMI.展开更多
The relatively low sensitivity is an important reason for restricting the microbial fuel cell(MFC)sensors'application in low concentration biodegradable organic matter(BOM)detection.The startup parameters,includin...The relatively low sensitivity is an important reason for restricting the microbial fuel cell(MFC)sensors'application in low concentration biodegradable organic matter(BOM)detection.The startup parameters,including substrate concentration,anode area and external resistance,were regulated to enhance the sensitivity of MFC sensors.The results demonstrated that both the substrate concentration and anode area were positively correlated with the sensitivity of MFC sensors,and an external resistance of 210Ωwas found to be optimal in terms of sensitivity of MFC sensors.Optimized MFC sensors had lower detection limit(1 mg/L)and higher sensitivity(Slope value of the linear regression curve was 1.02),which effectively overcome the limitation of low concentration BOM detection.The essential reason is that optimized MFC sensors had higher coulombic efficiency,which was beneficial to improve the sensitivity of MFC sensors.The main impact of the substrate concentration and anode area was to regulate the proportion between electrogens and nonelectrogens,biomass and living cells of the anode biofilm.The external resistance mainly affected the morphology structure and the proportion of living cells of the anode.This study demonstrated an effective way to improve the sensitivity of MFC sensors for low concentration BOM detection.展开更多
Endowing strain sensors with superhydrophobicity is of great importance to guarantee their long-term service under harsh environments(such as wet,acid,alkali and salt atmospheres),whereas,the development of superhydro...Endowing strain sensors with superhydrophobicity is of great importance to guarantee their long-term service under harsh environments(such as wet,acid,alkali and salt atmospheres),whereas,the development of superhydrophobic strain sensors remains a great challenge.Herein,we realized a superhydrophobic and highly sensitive sensor for subtle human motion detection by designing a superhydrophobic and electrically conductive coating on cotton textile,via a facile drop-coating method.The resultant strain sensor showed a large water contact angle of 161.3°and a low sliding angle of 3.8°The superhydrophobic characteristics can keep almost unchanged even after undergoing 1000 peeling cycles,1000 stretchingrelease cycles,and 1000 bending-releasing cycles,revealing its excellent mechanical robustness.High sensitivity with the maximum gage factor of 169 was achieved for the strain sensor under a small strain of0–10%,and the sensing performance also showed well durability.Moreover,our sensor can effectively detect various subtle human physiological signals and body motions even under harsh conditions.These admirable features make the sensor promising applications in wearable electronics,personalized health monitoring,sound recognition,and so on.展开更多
The World Health Organization has declared COVID-19 a pandemic.The demand for devices or systems to diagnose and track COVID-19 infections noninvasively not only in hospitals but also in home settings has led to incre...The World Health Organization has declared COVID-19 a pandemic.The demand for devices or systems to diagnose and track COVID-19 infections noninvasively not only in hospitals but also in home settings has led to increased interest in consumer-grade wearables.A common symptom of COVID-19 is dyspnea,which may manifest as an increase in respiratory and heart rates.In this paper,a novel piezoelectric strain sensor is presented for real-time monitoring of respiratory and heartbeat signals.A highly sensitive and stretchable piezoelectric strain sensor is fabricated using a piezoelectric film with a serpentine layout.The thickness of the patterned PVDF flexible piezoelectric strain sensor is only 168μm,and the voltage sensitivity reaches 0.97 mV/με.The effective modulus is 13.5 MPa,which allows the device to fit to the skin and detect the small strain exhibited by the human body.Chest vibrations are captured by the piezoelectric sensor,which produces an electrical output voltage signal conformally mapped with respiratory–cardiac activities.The separate heart activity and respiratory signals are extracted from the mixed respiratory–cardiac signal by an empirical mode decomposition data processing algorithm.By detecting vital signals such as respiratory and heart rates,the proposed device can aid early diagnosis and monitoring of respiratory diseases such as COVID-19.展开更多
The flourishing development in flexible electronics has provoked intensive research in flexible strain sensors to realize accurate perception acquisition under different external stimuli.However,building hydrogel-base...The flourishing development in flexible electronics has provoked intensive research in flexible strain sensors to realize accurate perception acquisition under different external stimuli.However,building hydrogel-based strain sensors with high stretchability and sensitivity remains a great challenge.Herein,MXene nanosheets were composited into polyacrylamide-sodium alginate matrix to construct mechanical robust and sensitive double networked hydrogel strain sensor.The hydrophilic MXene nanosheets formed strong interactions with the polymer matrix and endowed the hydrogel with excellent tensile properties(3150%),compliant mechanical strength(2.03 kPa^(-1)in Young’s Module)and long-lasting stability and fatigue resistance(1000 dynamic cycles under 1,600%strain).Due to the highly oriented MXene-based three dimensional conductive networks,the hydrogel sensor achieved extremely high tensile sensitivity(18.15 in gauge factor)and compression sensitivity(0.38 kPa^(-1)below 3 kPa).MXene hydrogel-based strain sensors also displayed negligible hysteresis in electromechanical performance,typical frequent-independent feature and rapid response time to external stimuli.Moreover,the sensor exhibited accurate response to different scales of human movements,providing potential application in speech recognition,expression recognition and handwriting verification.展开更多
According to the requirements of the high-sensitivity acquisition of Direct Sequence Spread Spectrum(DSSS) signals under ultrahigh dynamic environments in space communications, a three-dimensional joint search of the ...According to the requirements of the high-sensitivity acquisition of Direct Sequence Spread Spectrum(DSSS) signals under ultrahigh dynamic environments in space communications, a three-dimensional joint search of the phase of Pseudo-Noise-code(PN-code),Doppler frequency and its rate-of-change is presented to achieve high sensitivity in sensing high-frequency dynamics. By eliminating the correlation peak loss caused by ultrahigh Doppler frequency and its rate-of-change offset,the proposed method improves the acquisition sensitivity by increasing the non-coherent accumulation time. The validity of the algorithm is proved by theoretical analysis and simulation results. It is shown that signals with a carrier- to-noise ratio as low as 39 dBHz can be captured with high performance when the Doppler frequency is up to ±1 MHz and its rate-of-change is up to ±200 kHz/s.展开更多
文摘High-sensitivity sensors represent a critical frontier in modern sensing technology,driving innovations across fields such as biomedical monitoring,precision instrumentation,environmental detection,and indus-trial automation.As demands for accuracy,miniaturization,and reliability continue to grow,developing novel sensor architectures and functional materials has become essential to achieving enhanced performance under extreme or complex conditions.
基金supported by the Natural Science Foundation of Tianjin City (No.19JCYBJC17000)the National Natural Science Foundation of China (No.11905159)。
文摘A D-type photonic crystal fiber(PCF) sensor based on surface plasmon resonance(SPR) principle is designed.In order to excite the SPR effect,a gold film is plated on the open-loop channel of the sensor,the free electrons in a metal are resonated with photons.The structural parameters are fine-tuned and the sensing performance of the sensor is studied.The results show that the maximum spectral sensitivity reaches 18 000 nm/RIU in the refractive index range of 1.24—1.32,and the maximum resolution is 5.56×10^(-6) RIU.The novel structure with high sensitivity and low refractive index provides a new perspective for fluid density detection.
基金supported by the National Natural Science Foundation of China(51973166,52373097)Beijing Natural Science Foundation(2232064)。
文摘Pressure sensors are essential for a wide range of applica-tions,including health monitoring,industrial diagnostics,etc.However,achieving both high sensitivity and mechanical ability to withstand high pressure in a single material remains a significant challenge.This study introduces a high-performance cellulose hydrogel inspired by the biomi-metic layered porous structure of human skin.The hydrogel features a novel design composed of a soft layer with large macropores and a hard layer with small micropores,each of which contribute uniquely to its pressure-sensing capabilities.The macropores in the soft part facilitate significant deforma-tion and charge accumulation,providing exceptional sensitivity to low pressures.In contrast,the microporous structure in the hard part enhances pressure range,ensuring support under high pressures and preventing structural failure.The performance of hydrogel is further optimized through ion introduction,which improves its conductivity,and as well the sensitivity.The sensor demonstrated a high sensitivity of 1622kPa^(-1),a detec-tion range up to 160 kPa,excellent conductivity of 4.01 Sm^(-1),rapid response time of 33 ms,and a low detection limit of 1.6 Pa,outperforming most existing cellulose-based sensors.This innovative hierarchically porous architecture not only enhances the pressure-sensing performance but also offers a simple and effective approach for utilizing natural polymers in sensing technologies.The cellulose hydrogel demonstrates sig-nificant potential in both health monitoring and industrial applications,providing a sensitive,durable,and versatile solution for pressure sensing.
基金the National Key Research and Development Program of China(Grant No.2021YFB2012100)the Major Science and Technology Projects in Fujian Province(Grant No.2023HZ021005)+1 种基金the Open Project Program of Fujian Key Laboratory of Special Intelligent Equipment Measurement and Control(Grant No.FJIES2023KF06)the Industry-University-Research Co-operation Fund of the Eighth Research Institute of China Aerospace Science and Technology Corporation(Grant No.SAST2023-061).
文摘High-temperature thin-film strain sensors are advanced technological devices for monitoring stress and strain in extreme environments,but the coupling of temperature and strain at high temperature is a challenge for their use.Here,this issue is addressed by creating a composite ink that combines Pb_(2)Ru_(2)O_(6) and TiB_(2) using polysilazane(PSZ)as a binder.After direct writing and annealing the PSZ/Pb_(2)Ru_(2)O_(6)/TiB_(2) film at 800℃ in air,the resulting thin film exhibits a low temperature coefficient of resistance(TCR)of only 281 ppm/℃ over a wide temperature range from 100℃ to 700℃,while also demonstrating high sensitivity with a gauge factor approaching 19.8.This exceptional performance is attributed to the intrinsic properties of Pb_(2)Ru_(2)O_(6),which has positive TCR at high temperature,and TiB2,which has negative TCR at high temperature.Combining these materials reduces the overall TCR of the film.Tests showed that the PSZ/Pb_(2)Ru_(2)O_(6)/TiB_(2) film maintains stable strain responses and significant signal output even under varying temperature.These findings provide valuable insights for developing high-temperature strain sensors with low TCR and high sensitivity,highlighting their potential for applications in high-temperature strain measurements.
基金supported the Chongqing Natural Science Foundation(CSTB2023NSCQ-MSX0459&CSTB2023NSCQ-MSX0231)the Graduate Research and Innovation Foundation of Chongqing,China(CYB23048)+1 种基金the Fundamental Research Program under Grant(JCKY2022603C017)National Natural Science Foundation of China(NSFC 52175281).
文摘Electronic skin has showcased superior sensing capabilities inspired from human skin.However,most preceding studies focused on the dermis of the skin rather than the epidermis.In particular,the pseudo-porous structural domain of the epidermis increases the skin's tolerance while ensuring its susceptibility to touch.Yet,most endeavors on the porous structures failed to replicate the superior sensing performance of skin-like counterparts in terms of sensitivity and/or detection range.Stimulated by the strategy that the epidermis of the skin absorbs energy while producing ionic conduction to the nerves,this work initiatively introduced an easy-to-produce,and low-cost pressure sensor based on ionic-gel foam,and achieved a high sensitivity(2893 kPa^(-1))within a wide pressure range(up to~1 MPa),which ranked among the best cases thus far.Moreover,the factors affecting the sensor performance were explored while the sensing principles were enriched.Inspiringly,the plantar pressure measurement by harnessing the as-prepared sensor unveiled an ultra-broad detection range(100 Pa-1 MPa),thus delivering a huge application potential in the field of robot and health monitoring.
基金supported by the National Natural Science Foundation of China(52175270)the Project of Scientifc and Technological Development Plan of Jilin Province(20220508130RC)+3 种基金the Science and Technology Development Program of Jilin Province(YDZJ202501ZYTS370)the Scientific Research Project of Education Department of Jilin Province(JJKH20251196KJ)the Scientific Research Project of Education Department of Jilin Province(JJKH20251195KJ)the Key Project of State Key Laboratory of Changchun City(23GZZ14).
文摘Flexible piezoresistive sensors based on biomimetic microstructures are prospective for broad application in motion monitoring.However,the design and preparation processes of most biomimetic microstructures in the existing studies are complicated,and there are few studies on pore size control.Herein,the porous structure of human bones was used as a biomimetic prototype,and optimally designed by creating a theoretical equivalent sensor model and a finite element model.Soluble raw materials such as sugar and salt in different particle sizes were pressed into porous templates.Based on the template method,porous structures in different pore sizes were prepared using polydimethylsiloxane(PDMS)polymer as the substrate.On this basis,graphene oxide conductive coating was prepared with the modified Hummers method and then deposited via dip coating onto the substrate.Finally,a PDMS-based porous structure biomimetic flexible piezoresistive sensor was developed.Mechanically,the deformation of the sensor under the same load increased with the pore size rising from 0.3 to 1.5 mm.Electrically,the resistance rang of the sensor was enlarged as the pore size rose.The resistance variation rates of samples with pore sizes of 0.3,1.0,and 1.5 mm at approximately the 200th cycle were 63%,79%,and 81%,respectively;at the 500th cycle,these values were 63%,77%,and 79%;and at the 1000th cycle,they stabilized at 63%,74%,and 76%.These results indicate that the fabricated sensor exhibits high stability and fatigue resistance.At the pressure of 0–25 kPa,the sensitivity rose from 0.0688 to 0.1260 kPa−1,and the performance was enhanced by 83%.After 1,000 cycles of compression testing,the signal output was stable,and no damage was caused to the substrate.Further application tests showed the biomimetic sensor accurately and effectively identified human joint motions and gestures,and has potential application value in human motion monitoring.
基金support from Beijing Natural Science Foundation−Xiaomi Innovation Joint Fund(Grant No.L233009)the National Natural Science Foundation of China(NSFC Grant Nos.62422409,62174152 and 62374159)from the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2020115).
文摘High-performance flexible pressure sensors have garnered significant attention in fields such as wearable electronics and human-machine interfaces.However,the development of flexible pressure sensors that simultaneously achieve high sensitivity,a wide detection range,and good mechanical stability remains a challenge.In this paper,we propose a flexible piezoresistive pressure sensor based on a Ti_(3)C_(2)Tx(MXene)/polyethylene oxide(PEO)composite nanofiber membrane(CNM).The sensor,utilizing MXene(0.4 wt%)/PEO(5 wt%),exhibits high sensitivity(44.34 kPa^(−1)at 0−50 kPa,12.99 kPa^(−1)at 50−500 kPa)and can reliably monitor physiological signals and other subtle cues.Moreover,the sensor features a wide detection range(0−500 kPa),fast response and recovery time(~150/45 ms),and excellent mechanical stability(over 10000 pressure cycles at maximum load).Through an MXene/PEO sensor array,we demonstrate its applications in human physiological signal monitoring,providing a reliable way to expand the application of MXene-based flexible pressure sensors.
文摘Background The data on the prognostic values of high sensitivity C-reactive protein （hsCRP） levels in patients with advanced symp-tomatic heart failure （HF） receiving cardiac resynchronization therapy （CRT） are scarce. The aim of present study was to investigate the association of serum hsCRP levels with left ventricle reverse remodeling after six months of CRT as well as long-term outcome. Methods A total of 232 CRT patients were included. The assessment of hsCRP values, clinical status and echocardiographic data were performed at baseline and after six months of CRT. Long-term follow-up included all-cause mortality and hospitalizations for HF. Results During the mean follow-up periods of 31.3 ± 31.5 months, elevated hsCRP （〉3 mg/L） prior to CRT was associated with a significant 2.39-fold increase （P=0.006） in the risk of death or HF hospitalizations. At 6-month follow-up, patients who responded to CRT showed significant reductions or maintained low in hsCRP levels （–0.5 ± 4.1 mg/L reduction） compared with non-responders （1.7 ± 6.1 mg/L increase, P=0.018）. Com-pared with patients in whom 6-month hsCRP levels were reduced or remained low, patients in whom 6-month hsCRP levels were increased or maintained high experienced a significantly higher risk of subsequent death or HF hospitalizations （Log-rank P〈0.001）. The echocardio-graphic improvement was also better among patients in whom 6-month hsCRP levels were reduced or remained low compared to those in whom 6-month hsCRP levels were raised or maintained high. Conclusions Our findings demonstrated that measurement of baseline and follow-up hsCRP levels may be useful as prognostic markers for timely potential risk stratification and subsequent appropriate treatment strategies in patients with advanced HF undergoing CRT.
基金supported by the National Natural Science Foundation of China(51432001,51472217,51632008,U1609219)
文摘Thermal sensing and imaging in the physiological temperature range are of great importance for studying physiological processes and treating diseases. Metal-organic frameworks(MOFs) exhibit great promise for developing luminescent thermometers due to their remarkable structural diversities and tunable luminescence properties. Here, we synthesized a series of luminescent mixed-lanthanide MOFs,EuTbBPT(x = 0.019, 0.058, 0.106; H3 BPT = biphenyl-3,4’,5-tricarboxylate acid) and adopted powder X-ray diffraction(PXRD), thermogravimetric analysis(TGA) and Fourier transform infrared(FT-IR) to characterize the resulting products. The temperature-dependent photoluminescence emission spectra were recorded to investigate their potential applications in physiological temperature readout. It is found that the intensity ratio of Tbto Euis linearly correlated with temperature and the relative sensitivity is higher than 1.5%/℃ over the entire physiological temperature range. Furthermore,the temperaturedependent luminescence color emission allows for visual colorimetric temperature measurements.Luminescence lifetime testing and triplet energy level measurement were further conducted to study the mechanism.
基金Supported by the Ministry of Science and Higher Education grant(#MD-2314.2020.7).The authors declare no conflict of interest.
文摘1 Introduction Inflammation is one of the main mechanisms in the pathogenesis of atherosclerosis,and the interest to the evaluation of inflammatory biomarkers in coronary artery disease(CAD)has been increasing over the last decade.[1,2]Destabilization of chronic artery plaques,which leads to acute coronary syndromes,has been associated with inflammatory status.[1,3]。
基金Financial support from the grant from the City University of Hong Kong(SRG 7004918)South China University of Technology(National Key Research and Development Program of China,No.2016YFB0302000)Shenzhen University(Ten Thousand People’s Scheme,Project No.201,810,090,052)。
文摘With the prosperous development of artificial intelligence,medical diagnosis and electronic skins,wearable electronic devices have drawn much attention in our daily life.Flexible pressure sensors based on carbon materials with ultrahigh sensitivity,especially in a large pressure range regime are highly required in wearable applications.In this work,graphene membrane with a layer-by-layer structure has been successfully fabricated via a facile self-assembly and air-drying(SAAD)method.In the SAAD process,air-drying the self-assembled graphene hydrogels contributes to the uniform and compact layer structure in the obtained membranes.Owing to the excellent mechanical and electrical properties of graphene,the pressure sensor constructed by several layers of membranes exhibits high sensitivity(52.36 kPa……-1)and repeatability(short response and recovery time)in the loading pressure range of 0–50 kPa.Compared with most reported graphene-related pressure sensors,our device shows better sensitivity and wider applied pressure range.What’s more,we demonstrate it shows desired results in wearable applications for pulse monitoring,breathing detection as well as different intense motion recording such as walk,run and squat.It’s hoped that the facilely prepared layer-by-layer graphene membrane-based pressure sensors will have more potential to be used for smart wearable devices in the future.
基金financially supported by the National Natural Science Foundation of China (Nos.22075046,51972063,2150112751502185)+2 种基金Natural Science Funds for Distinguished Young Scholar of Fujian Province (No.2020J06038)Natural Science Foundation of Fujian Province (Nos.2020J01514,2019J01652,and2019J01256)111 Project (No.D17005)。
文摘Highly sensitive pressure sensors are often deployed in human-machine interaction area,touch screen and human motion detection.However,there are still great challenges to fabricating with high sensitivity pressure sensor with wide-range detection.Herein,we developed a new strategy to fabricate a highly sensitive pressure sensor using sandpaper and improve its detection range using a sacrificial template.It was the fthatirst time to combine microstructure processing with the sacrificial template method to fabricate pressure sensor.The microstructure of sandpaper endowed the sensor with high sensitivity,and the elastic substrate enhanced the sensor ability to resist high pressure without being damaged.The fabricated sensor device exhibits a superior sensitivity of 39.077 kPa-1in the range from 50 kPa to 110 kPa with a broad linear response.Remarkably,high pressure ceiling(<160 kPa) ensures that the sponge could be applied in different practical conditions to monitor a range of subtle human motions including finger,wrist bending,and pulse.For applications,the sensor device can not only detect the foot stepping behavior(0.7 MPa) but also produce an obvious response to an extremely slight paper(9 mg,~0.9 Pa).The successful preparation of this micro-structured elastic sponge material provided new ideas for exploring its potential applications in pressure sensors and flexible wearable electronic devices.
基金the support of the National High Technology Research and Development Program of China (863) (Grant No. 2012AA1406)
文摘In direct sequence spread spectrum communication both for satelliteto-ground and inter-satellite links, the system constrains due to radio frequency spectral occupation, channel data throughput and link performances in terms of data channel coding which might result in a signal structure where the symbol duration is shorter than the pseudo code period. This can generate some difficulties in the DSSS signal acquisition due to the polarity inversion caused by the data modulation. To eliminate the influence due to polarity inversion, this paper proposes a novel acquisition algorithm based on the simultaneous search of the code phase, data phase and Doppler frequency. In the proposed algorithm the data phase is predicted and the correlation period for the coherent integration can be set equal to the symbol duration. Then non-coherent accumulation over different symbol is implemented in order to enhance the acquisition algorithm sensitivity; the interval of non-coherent accumulation is the least common multiple between the symbol duration and the pseudo code period. The algorithm proposed can largely minimize the SNR loss caused by data polarity inversion and enhance acquisition performance without a noticeable increase in hardware complexity. Theoretical analysis, simulation and measured results verify the validity of the algorithm.
基金Project supported by the National Basic Research Program of China(Grant No.2010CB327601)
文摘We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case.
基金funded by research organizations in Tunisia(Ministry of Public Health and Ministry of Higher Education and Scientific Research)。
文摘Background Coronary artery disease(CAD)remains a leading cause of morbidity and mortality.Cytokines play a potential role in atherosclerosis pathogenesis and progression.We investigated the association between high sensitive C-reactive protein(hs CRP)and severity of CAD.Methods CAD patients were stratified according to hs CRP cut-off value into high levels hs CRP group(≥8.4 mg/L)and low levels hs CRP group(<8.4 mg/L).Severity of CAD was assessed according to artery stenosis degree and the number of vessel involved.Statistical analysis was performed using Statistical Package for the Social Sciences(SPSS,version 23.0).Results The mean age was 60.3±11.0 years.The level of hs CRP was increased and ranged from 0.2 to 1020.0 mg/L.Biochemical risk factors and severity of CAD didn’t show significant differences between the two groups.In multivariate linear analysis,cardiac troponin I(c Tn I)and serum amyloid A(SAA)were predictors of hs CRP.As shown in receiver operating characteristic(ROC)curve analysis performed in patients with ST-segment elevation myocardial infarction(STEMI)and compared to myonecrosis biomarkers,hs CRP(area under the curve(AUC):0.905;95%CI:0.844-0.966;P<0.001)could be a powerful predictor marker in evaluating the infarct size after myocardial infarction but not better than c Tn I.Conclusions Hs CRP levels were not associated with the severity of CAD but could be useful in the evaluation of myocardial necrosis in patients with STEMI.
基金supported by the National Natural Science Foundation of China(Nos.51525805,51727812 and 51808527)the Soft Science Research Project of Sichuan(No.2019JDR0286)the Special Research Assistant Program of Chinese Academy of Science。
文摘The relatively low sensitivity is an important reason for restricting the microbial fuel cell(MFC)sensors'application in low concentration biodegradable organic matter(BOM)detection.The startup parameters,including substrate concentration,anode area and external resistance,were regulated to enhance the sensitivity of MFC sensors.The results demonstrated that both the substrate concentration and anode area were positively correlated with the sensitivity of MFC sensors,and an external resistance of 210Ωwas found to be optimal in terms of sensitivity of MFC sensors.Optimized MFC sensors had lower detection limit(1 mg/L)and higher sensitivity(Slope value of the linear regression curve was 1.02),which effectively overcome the limitation of low concentration BOM detection.The essential reason is that optimized MFC sensors had higher coulombic efficiency,which was beneficial to improve the sensitivity of MFC sensors.The main impact of the substrate concentration and anode area was to regulate the proportion between electrogens and nonelectrogens,biomass and living cells of the anode biofilm.The external resistance mainly affected the morphology structure and the proportion of living cells of the anode.This study demonstrated an effective way to improve the sensitivity of MFC sensors for low concentration BOM detection.
基金financially supported by the National Key Research and Development Program of China(No.2018YFB0704200)the National Natural Science Foundation of China(Nos.51973142,21704070 and 51673134)+2 种基金the Science and Technology Department of Sichuan Province(No.2020YJ0318)the China Postdoctoral Science Found(Nos.2019T120838 and 2015M643471)the Fundamental Research Funds for the Central Universities(No.YJ201971)。
文摘Endowing strain sensors with superhydrophobicity is of great importance to guarantee their long-term service under harsh environments(such as wet,acid,alkali and salt atmospheres),whereas,the development of superhydrophobic strain sensors remains a great challenge.Herein,we realized a superhydrophobic and highly sensitive sensor for subtle human motion detection by designing a superhydrophobic and electrically conductive coating on cotton textile,via a facile drop-coating method.The resultant strain sensor showed a large water contact angle of 161.3°and a low sliding angle of 3.8°The superhydrophobic characteristics can keep almost unchanged even after undergoing 1000 peeling cycles,1000 stretchingrelease cycles,and 1000 bending-releasing cycles,revealing its excellent mechanical robustness.High sensitivity with the maximum gage factor of 169 was achieved for the strain sensor under a small strain of0–10%,and the sensing performance also showed well durability.Moreover,our sensor can effectively detect various subtle human physiological signals and body motions even under harsh conditions.These admirable features make the sensor promising applications in wearable electronics,personalized health monitoring,sound recognition,and so on.
基金We are grateful for funding from the Natural Science Foundation of China(NSFC Grant No.62001322)the Tianjin Municipal Science and Technology Project(No.20JCQNJC011200)+1 种基金the National Key Research and Development Program(No.2020YFB2008801)the Nanchang Institute for Microtechnology of Tianjin University.
文摘The World Health Organization has declared COVID-19 a pandemic.The demand for devices or systems to diagnose and track COVID-19 infections noninvasively not only in hospitals but also in home settings has led to increased interest in consumer-grade wearables.A common symptom of COVID-19 is dyspnea,which may manifest as an increase in respiratory and heart rates.In this paper,a novel piezoelectric strain sensor is presented for real-time monitoring of respiratory and heartbeat signals.A highly sensitive and stretchable piezoelectric strain sensor is fabricated using a piezoelectric film with a serpentine layout.The thickness of the patterned PVDF flexible piezoelectric strain sensor is only 168μm,and the voltage sensitivity reaches 0.97 mV/με.The effective modulus is 13.5 MPa,which allows the device to fit to the skin and detect the small strain exhibited by the human body.Chest vibrations are captured by the piezoelectric sensor,which produces an electrical output voltage signal conformally mapped with respiratory–cardiac activities.The separate heart activity and respiratory signals are extracted from the mixed respiratory–cardiac signal by an empirical mode decomposition data processing algorithm.By detecting vital signals such as respiratory and heart rates,the proposed device can aid early diagnosis and monitoring of respiratory diseases such as COVID-19.
基金supported by the National Natural Science Foundation of China(No.61775095)six talent peak innovation team in Jiangsu Province(No.TD-SWYY-009)“Taishan scholars”construction special fund of Shandong Province。
文摘The flourishing development in flexible electronics has provoked intensive research in flexible strain sensors to realize accurate perception acquisition under different external stimuli.However,building hydrogel-based strain sensors with high stretchability and sensitivity remains a great challenge.Herein,MXene nanosheets were composited into polyacrylamide-sodium alginate matrix to construct mechanical robust and sensitive double networked hydrogel strain sensor.The hydrophilic MXene nanosheets formed strong interactions with the polymer matrix and endowed the hydrogel with excellent tensile properties(3150%),compliant mechanical strength(2.03 kPa^(-1)in Young’s Module)and long-lasting stability and fatigue resistance(1000 dynamic cycles under 1,600%strain).Due to the highly oriented MXene-based three dimensional conductive networks,the hydrogel sensor achieved extremely high tensile sensitivity(18.15 in gauge factor)and compression sensitivity(0.38 kPa^(-1)below 3 kPa).MXene hydrogel-based strain sensors also displayed negligible hysteresis in electromechanical performance,typical frequent-independent feature and rapid response time to external stimuli.Moreover,the sensor exhibited accurate response to different scales of human movements,providing potential application in speech recognition,expression recognition and handwriting verification.
基金supported by the Youth Science Fund,National Natural Science Foundation of China under Grant No.61102130
文摘According to the requirements of the high-sensitivity acquisition of Direct Sequence Spread Spectrum(DSSS) signals under ultrahigh dynamic environments in space communications, a three-dimensional joint search of the phase of Pseudo-Noise-code(PN-code),Doppler frequency and its rate-of-change is presented to achieve high sensitivity in sensing high-frequency dynamics. By eliminating the correlation peak loss caused by ultrahigh Doppler frequency and its rate-of-change offset,the proposed method improves the acquisition sensitivity by increasing the non-coherent accumulation time. The validity of the algorithm is proved by theoretical analysis and simulation results. It is shown that signals with a carrier- to-noise ratio as low as 39 dBHz can be captured with high performance when the Doppler frequency is up to ±1 MHz and its rate-of-change is up to ±200 kHz/s.
