Multi-element array photoelectric detector is the core devices to form a photoelectric detection target with a large field of view.This photoelectric detection target brings about the problem of uneven detection sensi...Multi-element array photoelectric detector is the core devices to form a photoelectric detection target with a large field of view.This photoelectric detection target brings about the problem of uneven detection sensitivity distribution in the detection screen.To improve the uneven detection sensitivity of this photoelectric detection target,this paper analyzes the distribution law of the uneven detection sensitivity of the photoelectric detection target using the multi-element array photoelectric detector,dissects the main factors affecting the detection sensitivity according to the photoelectric detection principle,establishes the calculation model of detection sensitivity of the photoelectric detection target in the different detection areas and proposes a method to improve the detection sensitivity by compensating the gain of each unit photoelectric detector.The analysis of simulation and experimental results show that the proposed method of photoelectric detection target can effectively improve the output signal amplitude of the projectile under the certain detection distance,in particular,the output signal amplitude of the projectile is significantly increased when the projectile passes through the detection blind area.The experimental results are consistent with the simulation results,which verify the effectiveness of the proposed improvement method.展开更多
We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector(QWP)device with a peak response frequency of 4.3 THz.The negative differential resistance(NDR)phenomenon is found in the dark currentvolta...We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector(QWP)device with a peak response frequency of 4.3 THz.The negative differential resistance(NDR)phenomenon is found in the dark currentvoltage(I-V)curve in the current sweeping measurement mode,from which the breakdown voltage is determined.The photocurrent spectra and blackbody current responsivities at different voltages are measured.Based on the experimental data,the peak responsivity of 0.3 A/W(at 0.15 V,8 K)is derived,and the detection sensitivity is higher than 10^(11)Jones,which is in the similar level as that of the commercialized liquid-helium-cooled silicon bolometers.We attribute the high detection performance of the device to the small ohmic contact resistance of-2Ωand the big breakdown bias.展开更多
Well-defined raspberry-like magnetic microbeads （RMMBs） as immunoassay solid carriers were pre- pared by chemicM covalent binding between Fe304 magnetic microspheres and SiO2 nanoparticles. These RMMBs were not as a...Well-defined raspberry-like magnetic microbeads （RMMBs） as immunoassay solid carriers were pre- pared by chemicM covalent binding between Fe304 magnetic microspheres and SiO2 nanoparticles. These RMMBs were not as agglomerative as nano-sized magnetie particles （〈 200 nm）, which was an advangtage for high efficient magnetic separation. When compared to Fe304@SiO2 core-shell magnetic microbeads （CMMBs） with smooth surface, RMMBs exhibited stronger capacity to bind biomolecules. Limit of blank （LOB） and limit of detection （LoD） of HBsAg detection using RMMBs as carriers via chemiluminiscence immunoassay （CLIA） were 0.472 and 1.022 μg/L, respectively, showing a notable improvement compared with CMMBs whose LoB and LoD were 1.017 and 1.988 μg/L, respectively. All these indicated a great potential of RMMBs in immunoassay application.展开更多
Flexible pressure sensors have excellent prospects in applications of human-machine interfaces,artificial intelligence and human health monitoring due to their bendable and lightweight characteristics compared to rigi...Flexible pressure sensors have excellent prospects in applications of human-machine interfaces,artificial intelligence and human health monitoring due to their bendable and lightweight characteristics compared to rigid pressure sensors.However,arising from the limited compressibility of soft materials and the hardening of microstructures at the device interface,there is always a trade-off between high sensitivity and broad sensing range for most flexible pressure sensors,which results in a gradual saturation response and limits their practical applications.Herein,inspired by the distinct pressure perception function of crocodile receptors,a highly sensitive and wide-range flexible pressure sensor with multiscale microdomes and interlocked architecture is developed via a facile PS-decorated molding method.Combined with interlocked architecture,the multiscale dome-shaped structured interface enhances the compressibility of the material through structural complementarity,increases the contact area between functional materials,which compensates for the stiffness induced by the deformation of dense microscale columns.This effectively mitigates structural hardening across a wide pressure range,leading to the overall high performance of the sensor.As a result,the obtained sensor exhibits a low detection limit of 5 Pa,a high sensitivity of 6.14 kPa^(-1),a wide measurement range up to 231 kPa,short response/recovery time of 56 ms/69 ms,outstanding stability over 10,000 cycles.Considering these excellent properties,the sensor shows promising potential in health monitoring,human-computer interaction,wearable electronics.This study presents a strategy for the fabrication of flexible pressure sensors exhibiting high sensitivity and a wide pressure response range.展开更多
Polydiacetylene(PDA)liposomes have been widely applied for detection due to their distinctive optical properties.How-ever,the liquid phase in which PDA liposomes are dispersed generates several drawbacks,for instance,...Polydiacetylene(PDA)liposomes have been widely applied for detection due to their distinctive optical properties.How-ever,the liquid phase in which PDA liposomes are dispersed generates several drawbacks,for instance,instability,compromise of detection sensitivity induced by dilution,and separation of target sampling and detection,making it inconvenient for application.In this paper,various functionalized PDA liposomes for detecting target were prepared,which were also immobilized into swelling microneedles to construct a solid-phase detection system.The PDA lipo-somes-complexed microneedles(PDA/MNs)enable the integration of target sampling and detection in one platform.The effects of the dispersing matrix phase on the detection sensitivity of PDA liposomes were systematically investi-gated from both environmental and chemical perspectives.PDA/MNs exhibited higher sensitivity than their counter-parts in liquid phase.PDA/MNs were optimized and validated for lead ion(Pb^(2+))and sialic acid(SA)detections.For Pb^(2+) detection,the limit of detection(LOD)of the PDA/MNs was 13.7 mM and 2.5 times lower than the liquid phase.For SA detection,the LOD of the PDA/MNs was 0.83 mM and 1.7 times lower than the liquid phase.The results suggested that such PDA/MNs were validated to provide a label-free,stable,sensitive,and convenient tool in an all-in-one manner for physiologic target detection.展开更多
In vitro detection method for the sensitivity of Magnaporthe grisea to tricyclazole was studied, and the potential resistance risk of blast disease to tricyclazole was assessed. Both EC50 of hyphal melanization (EC50-...In vitro detection method for the sensitivity of Magnaporthe grisea to tricyclazole was studied, and the potential resistance risk of blast disease to tricyclazole was assessed. Both EC50 of hyphal melanization (EC50-H) and minimum inhibitive concentration of melanization in appressorial (MIC-A) by inhibitor tricyclazole showed positive correlation to the EC50 of tricyclazole against blast disease tested in vivo, with relative co-efficiency (R5) of 0.8995 and 0.8244, respectively. However, stability and reproducibility of EC50-H were better than those of MIC-A, suggesting that it could be used to detect the sensitivity of M. grisea to tricyclazole in vitro. Tricyclazole sensitivity of the progenies derived from single spores of the most sensitive isolate DY2 and the least sensitive isolate GY6 detected in sensitivity monitoring in 2000 was not stable, with mean EC50 values of 4.4968 μg/mL and 5.4010 ug/mL, respectively, indicating that the difference in EC50 between DY2 and GY6 was not caused probably by resistance variation. EC50 of GY6 did not increase significantly when continuously selected for twenty generations under the selection pressure of tricyclazole in vivo. However, the sensitivity of DY2 was decreased by 10-fold after selected for twenty generations. The results suggested that tricyclazole was still low resistance risk for M. grisea in China.展开更多
Structural damage detection is hard to conduct in large-scale civil structures due to enormous structural data and insufficient damage features.To improve this situation,a damage detection method based on model reduct...Structural damage detection is hard to conduct in large-scale civil structures due to enormous structural data and insufficient damage features.To improve this situation,a damage detection method based on model reduction and response reconstruction is presented.Based on the framework of two-step model updating including substructure-level localization and element-level detection,the response reconstruction strategy with an improved sensitivity algorithm is presented to conveniently complement modal information and promote the reliability of model updating.In the iteration process,the reconstructed response is involved in the sensitivity algorithm as a reconstruction-related item.Besides,model reduction is applied to reduce computational degrees of freedom(DOFs)in each detection step.A numerical truss bridge is modelled to vindicate the effectiveness and efficiency of the method.The results showed that the presented method reduces the requirement for installed sensors while improving efficiency and ensuring accuracy of damage detection compared to traditional methods.展开更多
With a unique and large size of testing results of 1,842 samples collected from 12 wastewater treatment plants (WWTP) for 14 months through from low to high prevalence of COVID-19,the sensitivity of RT-qPCR detection ...With a unique and large size of testing results of 1,842 samples collected from 12 wastewater treatment plants (WWTP) for 14 months through from low to high prevalence of COVID-19,the sensitivity of RT-qPCR detection of SARS-CoV-2 RNA in wastewater that correspond to the communities was computed by using Probit analysis.This study determined the number of new COVID-19 cases per 100,000 population required to detect SARS-CoV-2RNA in wastewater at defined probabilities and provided an evidence-based framework of wastewater-based epidemiology surveillance (WBE).Input data were positive and negative test results of SARS-CoV-2 RNA in wastewater samples and the corresponding new COVID-19 case rates per 100,000 population served by each WWTP.The analyses determined that RT-qPCR-based SARS-CoV-2 RNA detection threshold at 50%,80%and 99%probability required a median of 8 (range:4-19),18 (9-43),and 38 (17-97) of new COVID-19 cases/100,000,respectively.Namely,the positive detection rate at 50%,80%and 99%probability were 0.01%,0.02%,and 0.04%averagely for new cases in the population.This study improves understanding of the performance of WBE SARS-CoV-2 RNA detection using the large datasets and prolonged study period.Estimated COVID-19 burden at a community level that would result in a positive detection of SARS-CoV-2 in wastewater is critical to support WBE application as a supplementary warning/monitoring system for COVID-19 prevention and control.展开更多
Aim to detect the characteristic weak magnetic field signal against the strong noises background. Methods In combination with a low-pass-filter, the correlation output of magne-* tic sensors between the magnetic field...Aim to detect the characteristic weak magnetic field signal against the strong noises background. Methods In combination with a low-pass-filter, the correlation output of magne-* tic sensors between the magnetic field and reference current was utilized to provide a DC output voltage proportional to the applied magnetic induction, computer simulation was* done to investigate the correlation output of the Hall-effect sensors. Results Some analysis results concerning the noise property, harmonic supppression and the sensitivity were given. Conclsion The minimum detection signal of the equipment evolved from the mentioned cor-* relation theory can be 10-6 T. In addition to the DC output, such sensors can also measure the phase of the detected magnetic induction and has good harmonic suppression as well as* noise elimination.展开更多
This paper reports a high-performance H2S gas sensing material that is made of ZnO nanowires(NWs)modified by an optimal amount of ZnS to form nano-hete rojunctions.Compared with the intrinsic ZnONWs,the three differen...This paper reports a high-performance H2S gas sensing material that is made of ZnO nanowires(NWs)modified by an optimal amount of ZnS to form nano-hete rojunctions.Compared with the intrinsic ZnONWs,the three differently modified nano-heterostructure material ZnO-ZnS-x(x=5,10,15)shows significant improvement in sensing performance to H2S at the working temperatures of 100-400℃,especially in the low temperature range(<300℃).The chemiresistive sensor with ZnO-ZnS-10 sensingmaterial exhibits the largest response signal to H2S among all the other ZnO-ZnS-x(x=5,10,15,20)sensors.Its response signal to 5 ppm H2S at 150℃is about 2.7 times to that of the ZnO-NWs sensor.Besides,the ZnO-ZnS-10 sensor also features satisfactory selectivity and repeatability at 150℃.With the technical advantage attributed to the reduction of the redesigned band gap at the interface between ZnO and ZnS,the ZnO-ZnS hete ro structure sensor rather than the traditional ZnO-NWs sensor can be used for high-sensitivity application at low working temperature.展开更多
Hydrazine hydrate(DH)is an important fine chemical intermediate and as fuel for rockets,however,it also has serious toxic for humans and environment.Developing novel materials and methods for sensitive detection of DH...Hydrazine hydrate(DH)is an important fine chemical intermediate and as fuel for rockets,however,it also has serious toxic for humans and environment.Developing novel materials and methods for sensitive detection of DH in water and air is an important task.In order to effectively detect DH,a novel conductive supramolecular polymer metallogel(PQ-Ag)has been constructed by the coordination of bis-5-hydroxyquinoline functionalized pillar[5]arene(PQ5)with Ag+.The metallogel PQ-Ag could realize the multi-channel sensitive detection of DH through naked-eye,fluorescence,and electrochemical methods.The lowest limit of detection(LOD)is 0.1 mg/m^(3)in air and 2.68×10^(−8)mol/L in water,which is lower than the standard of the US Environmental Protection Agency(EPA)for DH of maximum allowable concentration in drinking water.More importantly,an electronic device for DH detection based on the metallogel PQ-Ag was designed and prepared,which can realize conveniently and efficiently multi-channel detection and alert of DH through sound and light alarms not only in water but also in air.展开更多
Strontium-90,a highly radioactive isotope,accumulates within the food chain and skeletal structure,posing significant risks to human health.There is a critical need for a sensitive detection strategy for Strontium-90 ...Strontium-90,a highly radioactive isotope,accumulates within the food chain and skeletal structure,posing significant risks to human health.There is a critical need for a sensitive detection strategy for Strontium-90 in complex environmental samples.Here,solid-state nanochannels,modified with metal-organic frameworks(MOF)and specific aptamers,were engineered for highly sensitive detection of strontium ion(Sr^(2+)).The synergistic effect between the reduced effective diameter of the nanochannels due to MOF and the specific binding of Sr^(2+) by aptamers amplifies the difference in ionic current signals,enhancing detection sensitivity significantly.The MOF-modified nanochannels exhibit highly sensitive detection of Sr^(2+),with a limit of detection(LOD)being 0.03 nmol·L^(-1),whereas the LOD for anodized aluminum oxide(AAO)without the modified MOF nanosheets is only 1000 nmol·L^(-1).These findings indicate that the LOD of Sr^(2+) detected by the MOF-modified nanochannels is approximately 33,000 times higher than that by the nanochannels without MOF modification.Additionally,the highly reliable detection of Sr^(2+) in various water samples was achieved,with a recovery rate ranging from 94.00%to 118.70%.This study provides valuable insights into the rapidly advancing field of advanced nanochannel-based sensors and their diverse applications for analyzing complex samples,including environmental contaminant detection,food analysis,medical diagnostics,and more.展开更多
Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO：LiNbO 3 crystal...Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO：LiNbO 3 crystals pumped at 1.064 μm.The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm,corresponding to a pumpto-idler photon conversion efficiency of 25%.By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region,one can measure very week mid-infrared radiation with ordinary detectors,which are insensitive to mid-infrared radiation,with a very high gain.A maximum gain factor of about 7 脳 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse.展开更多
A simple technique for sensitive detection of heroine based on surface- plasmonresonance has been theoretically and experimentally investigated. The experiment was realized by using an anti-MO monoclonal antibody and ...A simple technique for sensitive detection of heroine based on surface- plasmonresonance has been theoretically and experimentally investigated. The experiment was realized by using an anti-MO monoclonal antibody and a morphine (MO)-bovine serum albumin (MOBSA) conjugate (antigen). The reason for using MO-BSA in the detection of heroine was also discussed. MO-BSA was immobilized on a gold thin film of SPR sensor chip by physical adsorption. The configuration of the device is allowed to be further miniaturized, which is required for the construction of a portable SPR device in the application of in-situ analysis.展开更多
Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for...Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid （DNA） hybridization. The Au-gated AIInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current （VDS = 0.5 V） shows a clear decrease of 69μA upon the introduction of 1μmolL^-1 （μM） complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.展开更多
Optical wireless(OW)communication systems face significant challenges such as signal attenuation due to atmospheric absorption,scattering,and noise from hardware components,which degrade detection sensitivity.To addre...Optical wireless(OW)communication systems face significant challenges such as signal attenuation due to atmospheric absorption,scattering,and noise from hardware components,which degrade detection sensitivity.To address these challenges,we propose a digital processing algorithm that combines finite impulse response filtering with dynamic synchronization based on pulse addition and subtraction.Unlike conventional methods,which typically rely solely on hardware optimization or basic thresholding techniques,the proposed approach integrates filtering and synchronization to improve weak signal detection and reduce noise-induced errors.The proposed algorithm was implemented and verified using a field-programmable gate array.Experiments conducted in an indoor OW communication environment demonstrate that the proposed algorithm significantly improves detection sensitivity by approximately 6 dB and 5 dB at communication rates of 3.5 Mbps and 5.0 Mbps,respectively.Specifically,under darkroom conditions and a bit error rate of 1×10^(-7),the detection sensitivity was improved from-38.56 dBm to-44.77 dBm at 3.5 Mbps and from-37.12 dBm to-42.29 dBm at 5 Mbps.The proposed algorithm is crucial for future capture and tracking of signals at large dispersion angles and in underwater and long-distance communication scenarios.展开更多
This study employs an N-carboxyanhydride ring-opening polymerization(NCA ROP)signal amplification strategy to construct a novel sensing system for the simple and rapid detection of tobacco mosaic virus RNA(tRNA).In th...This study employs an N-carboxyanhydride ring-opening polymerization(NCA ROP)signal amplification strategy to construct a novel sensing system for the simple and rapid detection of tobacco mosaic virus RNA(tRNA).In the developed fluorescent biosensor,carboxylated biomagnetic beads serve as carriers for target capture based on the complementary pairing of the aptamer bases.Subsequently,NCA ROP fluorescent peptides are utilized as highly biocompatible signal carriers to achieve sensitive detection of the target.Under the optimal conditions,the biosensor exhibits a broad linear detection range from 1 pM to 10 nM,with a detection limit as low as 0.085 pM.Furthermore,the fluorescent aptamer biosensor demonstrates robust affinity and reliability in recovery experiments involving healthy R ehmannia glutinosa leaf total RNA.This work establishes a robust platform for tRNA analysis,facilitating real-time and early diagnosis of various plant viruses.展开更多
Prunus necrotic ring spot virus （PNRSV） and grapevine fanleaf virus （GFLV） were detected by fluoroimmunoassay using bacterial magnetic particles （BMPs）, and a double antibody sandwich enzyme linked immunosorbent...Prunus necrotic ring spot virus （PNRSV） and grapevine fanleaf virus （GFLV） were detected by fluoroimmunoassay using bacterial magnetic particles （BMPs）, and a double antibody sandwich enzyme linked immunosorbent assay （DAS-ELISA）. For the fluoroimmunoassay, fluorescein isothiocyanate labeled anti-PNRSV antibody or anti-GFLV antibody was conjugated onto BMPs of Magnetospirillum gryphiswaldense MSR-1. With this method, a very low minimum antigen concentration （1×10^6 dilution of the original sample concentration） could be detected. Using DAS-ELISA, the minimum antigen detection concentration was the original sample concentration. Thus, comparing these two methods, a BMP-based method could increase the sensitivity up to six orders of magnitude （10^6） higher than an ELISA-based method of detection PNRSV and GFLV.展开更多
In this work, a binary-mixed-brushes-coated (BBC) capillary with switchable protein adsorption/desorption properties was developed and applied for on-line preconcentration of proteins. Firstly, amine-terminated poly(2...In this work, a binary-mixed-brushes-coated (BBC) capillary with switchable protein adsorption/desorption properties was developed and applied for on-line preconcentration of proteins. Firstly, amine-terminated poly(2-methyl-2-oxazoline)(PMOXA-NH2) and thiolterminated poly(acrylic acid)(PAA-SH) were synthesized by using cationic ring-opening polymerization (CROP) and reversible addition fragmentation chain transfer (RAFT) polymerization, respectively. Then, the BBC capillary based on poly(2-methyl-2-oxazoline)(PMOXA) and poly(acrylic acid)(PAA) was prepared by sequentially grafting of PMOXA-NH2 and PAA-SH onto fused-silica capillary inner surface through poly(dopamine)(PDA) as an anchor. The obtained PMOXA/PAA coating formed on the capillary or capillary's raw material was characterized in terms of the thickness, surface chemical composition by using scanning electron microscope (SEM) and X-ray photoelectron spectrum (XPS). The switchable protein adsorption/desorption performance of the BBC capillary was investigated by using fluorescence microscope under di erent solutions with certain pH and ionic strength(I). The results showed that bovine serum albumin (BSA) could be adsorbed on BBC capillary at pH=5.0 (I=10^-5 mol/L), and then the adsorbed BSA could be released at pH=9.0 (I=0.1 mol/L). This switchable protein adsorption/desorption property of coated capillary was then used to preconcentrate proteins on-line for increasing the detection sensitivity of BSA in capillary electrophoresis (CE). With this method, a sensitivity enhancement factor (SEF) more than 5000 for BSA detection was obtained.展开更多
Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequenci...Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequencies of SAW devices are typically limited to within a few gigahertz, which severely restricts their applications in 5G communication, precision sensing, photonics, and quantum control. To solve this critical problem, we propose a hybrid strategy that integrates a nanomanufacturing process (i.e., nanolithography) with a LiNbO_(3)/SiO_(2)/SiC heterostructure and successfully achieve a record-breaking frequency of about 44 GHz for SAW devices, in addition to large electromechanical coupling coefficients of up to 15.7%. We perform a theoretical analysis and identify the guided higher order wave modes generated on these slow-on-fast SAW platforms. To demonstrate the superior sensing performance of the proposed ultra-high-frequency SAW platforms, we perform micro-mass sensing and obtain an extremely high sensitivity of approximately 33151.9 MHz·mm2·μg−1, which is about 1011 times higher than that of a conventional quartz crystal microbalance (QCM) and about 4000 times higher than that of a conventional SAW device with a frequency of 978 MHz.展开更多
基金supported by Project of the Xi’an Science and Technology Innovation talent service enterprise project(No.2020KJRC0041)National Natural Science Foundation of China(No.62073256)Key Programs of Shaanxi Science and Technology Department(No.2020GY-125)。
文摘Multi-element array photoelectric detector is the core devices to form a photoelectric detection target with a large field of view.This photoelectric detection target brings about the problem of uneven detection sensitivity distribution in the detection screen.To improve the uneven detection sensitivity of this photoelectric detection target,this paper analyzes the distribution law of the uneven detection sensitivity of the photoelectric detection target using the multi-element array photoelectric detector,dissects the main factors affecting the detection sensitivity according to the photoelectric detection principle,establishes the calculation model of detection sensitivity of the photoelectric detection target in the different detection areas and proposes a method to improve the detection sensitivity by compensating the gain of each unit photoelectric detector.The analysis of simulation and experimental results show that the proposed method of photoelectric detection target can effectively improve the output signal amplitude of the projectile under the certain detection distance,in particular,the output signal amplitude of the projectile is significantly increased when the projectile passes through the detection blind area.The experimental results are consistent with the simulation results,which verify the effectiveness of the proposed improvement method.
基金Project supported by the National Key R&D Program of China(Grant No.2017YFF0106302)the National Basic Research Program of of China(Grant No.2014CB339803)+1 种基金the National Natural Science Foundation of China(Grant Nos.61404150,61405233,and 61604161)the Shanghai Municipal Commission of Science and Technology,China(Grant Nos.15JC1403800,17ZR1448300,and 17YF1429900)
文摘We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector(QWP)device with a peak response frequency of 4.3 THz.The negative differential resistance(NDR)phenomenon is found in the dark currentvoltage(I-V)curve in the current sweeping measurement mode,from which the breakdown voltage is determined.The photocurrent spectra and blackbody current responsivities at different voltages are measured.Based on the experimental data,the peak responsivity of 0.3 A/W(at 0.15 V,8 K)is derived,and the detection sensitivity is higher than 10^(11)Jones,which is in the similar level as that of the commercialized liquid-helium-cooled silicon bolometers.We attribute the high detection performance of the device to the small ohmic contact resistance of-2Ωand the big breakdown bias.
基金the National Natural Science Foundation of China(No.21075082)the National High Technology Research and Development Program(863) of China(No.2012AA020103)+3 种基金the Shanghai Nano Program(No.11nm0505600)the Shanghai Jiao Tong University Funding(No.YG2012ZD03)the 2012 Shanghai Jiao Tong University and University of Michigan Collaborative Research Projects(No.12X120010007)the Shanghai Municipal Education Commission Project(No.14ZZ023)
文摘Well-defined raspberry-like magnetic microbeads （RMMBs） as immunoassay solid carriers were pre- pared by chemicM covalent binding between Fe304 magnetic microspheres and SiO2 nanoparticles. These RMMBs were not as agglomerative as nano-sized magnetie particles （〈 200 nm）, which was an advangtage for high efficient magnetic separation. When compared to Fe304@SiO2 core-shell magnetic microbeads （CMMBs） with smooth surface, RMMBs exhibited stronger capacity to bind biomolecules. Limit of blank （LOB） and limit of detection （LoD） of HBsAg detection using RMMBs as carriers via chemiluminiscence immunoassay （CLIA） were 0.472 and 1.022 μg/L, respectively, showing a notable improvement compared with CMMBs whose LoB and LoD were 1.017 and 1.988 μg/L, respectively. All these indicated a great potential of RMMBs in immunoassay application.
基金supported by the National Natural Science Foundation of China(No.52175269)the Innovative Research Groups of the National Natural Science Foundation of China(No.52021003)+2 种基金Natural Science Foundation of Jilin Province of China(No.20210101052JC)Science and Technology Research Project of Education Department of Jilin Province(JJKH20231146KJ,JJKH20241262KJ)China Postdoctoral Science Foundation(2024M751086).
文摘Flexible pressure sensors have excellent prospects in applications of human-machine interfaces,artificial intelligence and human health monitoring due to their bendable and lightweight characteristics compared to rigid pressure sensors.However,arising from the limited compressibility of soft materials and the hardening of microstructures at the device interface,there is always a trade-off between high sensitivity and broad sensing range for most flexible pressure sensors,which results in a gradual saturation response and limits their practical applications.Herein,inspired by the distinct pressure perception function of crocodile receptors,a highly sensitive and wide-range flexible pressure sensor with multiscale microdomes and interlocked architecture is developed via a facile PS-decorated molding method.Combined with interlocked architecture,the multiscale dome-shaped structured interface enhances the compressibility of the material through structural complementarity,increases the contact area between functional materials,which compensates for the stiffness induced by the deformation of dense microscale columns.This effectively mitigates structural hardening across a wide pressure range,leading to the overall high performance of the sensor.As a result,the obtained sensor exhibits a low detection limit of 5 Pa,a high sensitivity of 6.14 kPa^(-1),a wide measurement range up to 231 kPa,short response/recovery time of 56 ms/69 ms,outstanding stability over 10,000 cycles.Considering these excellent properties,the sensor shows promising potential in health monitoring,human-computer interaction,wearable electronics.This study presents a strategy for the fabrication of flexible pressure sensors exhibiting high sensitivity and a wide pressure response range.
基金funded by the Natural Science Foundation of Shandong Province(ZR2022MC033)the Qingdao Science&Technology Benefiting People Project(24-1-8-smjk-11-nsh).
文摘Polydiacetylene(PDA)liposomes have been widely applied for detection due to their distinctive optical properties.How-ever,the liquid phase in which PDA liposomes are dispersed generates several drawbacks,for instance,instability,compromise of detection sensitivity induced by dilution,and separation of target sampling and detection,making it inconvenient for application.In this paper,various functionalized PDA liposomes for detecting target were prepared,which were also immobilized into swelling microneedles to construct a solid-phase detection system.The PDA lipo-somes-complexed microneedles(PDA/MNs)enable the integration of target sampling and detection in one platform.The effects of the dispersing matrix phase on the detection sensitivity of PDA liposomes were systematically investi-gated from both environmental and chemical perspectives.PDA/MNs exhibited higher sensitivity than their counter-parts in liquid phase.PDA/MNs were optimized and validated for lead ion(Pb^(2+))and sialic acid(SA)detections.For Pb^(2+) detection,the limit of detection(LOD)of the PDA/MNs was 13.7 mM and 2.5 times lower than the liquid phase.For SA detection,the LOD of the PDA/MNs was 0.83 mM and 1.7 times lower than the liquid phase.The results suggested that such PDA/MNs were validated to provide a label-free,stable,sensitive,and convenient tool in an all-in-one manner for physiologic target detection.
文摘In vitro detection method for the sensitivity of Magnaporthe grisea to tricyclazole was studied, and the potential resistance risk of blast disease to tricyclazole was assessed. Both EC50 of hyphal melanization (EC50-H) and minimum inhibitive concentration of melanization in appressorial (MIC-A) by inhibitor tricyclazole showed positive correlation to the EC50 of tricyclazole against blast disease tested in vivo, with relative co-efficiency (R5) of 0.8995 and 0.8244, respectively. However, stability and reproducibility of EC50-H were better than those of MIC-A, suggesting that it could be used to detect the sensitivity of M. grisea to tricyclazole in vitro. Tricyclazole sensitivity of the progenies derived from single spores of the most sensitive isolate DY2 and the least sensitive isolate GY6 detected in sensitivity monitoring in 2000 was not stable, with mean EC50 values of 4.4968 μg/mL and 5.4010 ug/mL, respectively, indicating that the difference in EC50 between DY2 and GY6 was not caused probably by resistance variation. EC50 of GY6 did not increase significantly when continuously selected for twenty generations under the selection pressure of tricyclazole in vivo. However, the sensitivity of DY2 was decreased by 10-fold after selected for twenty generations. The results suggested that tricyclazole was still low resistance risk for M. grisea in China.
基金Projects(51925808,52078504)supported by the National Natural Science Foundation of ChinaProject(2022JJ10082)supported by the Natural Science Fund for Distinguished Young Scholar of Hunan Province,ChinaProject(2021RC3016)supported by the Science and Technology Innovation Program of Hunan Province,China。
文摘Structural damage detection is hard to conduct in large-scale civil structures due to enormous structural data and insufficient damage features.To improve this situation,a damage detection method based on model reduction and response reconstruction is presented.Based on the framework of two-step model updating including substructure-level localization and element-level detection,the response reconstruction strategy with an improved sensitivity algorithm is presented to conveniently complement modal information and promote the reliability of model updating.In the iteration process,the reconstructed response is involved in the sensitivity algorithm as a reconstruction-related item.Besides,model reduction is applied to reduce computational degrees of freedom(DOFs)in each detection step.A numerical truss bridge is modelled to vindicate the effectiveness and efficiency of the method.The results showed that the presented method reduces the requirement for installed sensors while improving efficiency and ensuring accuracy of damage detection compared to traditional methods.
基金supported by research grants from the Canadian Institutes of Health Research [grant number VR5-172701, 2020]Alberta Innovates and Alberta Health [grant number RES0051047, 2020]。
文摘With a unique and large size of testing results of 1,842 samples collected from 12 wastewater treatment plants (WWTP) for 14 months through from low to high prevalence of COVID-19,the sensitivity of RT-qPCR detection of SARS-CoV-2 RNA in wastewater that correspond to the communities was computed by using Probit analysis.This study determined the number of new COVID-19 cases per 100,000 population required to detect SARS-CoV-2RNA in wastewater at defined probabilities and provided an evidence-based framework of wastewater-based epidemiology surveillance (WBE).Input data were positive and negative test results of SARS-CoV-2 RNA in wastewater samples and the corresponding new COVID-19 case rates per 100,000 population served by each WWTP.The analyses determined that RT-qPCR-based SARS-CoV-2 RNA detection threshold at 50%,80%and 99%probability required a median of 8 (range:4-19),18 (9-43),and 38 (17-97) of new COVID-19 cases/100,000,respectively.Namely,the positive detection rate at 50%,80%and 99%probability were 0.01%,0.02%,and 0.04%averagely for new cases in the population.This study improves understanding of the performance of WBE SARS-CoV-2 RNA detection using the large datasets and prolonged study period.Estimated COVID-19 burden at a community level that would result in a positive detection of SARS-CoV-2 in wastewater is critical to support WBE application as a supplementary warning/monitoring system for COVID-19 prevention and control.
文摘Aim to detect the characteristic weak magnetic field signal against the strong noises background. Methods In combination with a low-pass-filter, the correlation output of magne-* tic sensors between the magnetic field and reference current was utilized to provide a DC output voltage proportional to the applied magnetic induction, computer simulation was* done to investigate the correlation output of the Hall-effect sensors. Results Some analysis results concerning the noise property, harmonic supppression and the sensitivity were given. Conclsion The minimum detection signal of the equipment evolved from the mentioned cor-* relation theory can be 10-6 T. In addition to the DC output, such sensors can also measure the phase of the detected magnetic induction and has good harmonic suppression as well as* noise elimination.
基金the support from National Key R&D Program of China(No.2016YFA0200800)the National Natural Science Foundation of China(Nos.61527818,61834007,61604165,61571430,61874130,61674160)Science and Technology Development Fund of Shanghai Institute of Technology。
文摘This paper reports a high-performance H2S gas sensing material that is made of ZnO nanowires(NWs)modified by an optimal amount of ZnS to form nano-hete rojunctions.Compared with the intrinsic ZnONWs,the three differently modified nano-heterostructure material ZnO-ZnS-x(x=5,10,15)shows significant improvement in sensing performance to H2S at the working temperatures of 100-400℃,especially in the low temperature range(<300℃).The chemiresistive sensor with ZnO-ZnS-10 sensingmaterial exhibits the largest response signal to H2S among all the other ZnO-ZnS-x(x=5,10,15,20)sensors.Its response signal to 5 ppm H2S at 150℃is about 2.7 times to that of the ZnO-NWs sensor.Besides,the ZnO-ZnS-10 sensor also features satisfactory selectivity and repeatability at 150℃.With the technical advantage attributed to the reduction of the redesigned band gap at the interface between ZnO and ZnS,the ZnO-ZnS hete ro structure sensor rather than the traditional ZnO-NWs sensor can be used for high-sensitivity application at low working temperature.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.22065031,22061039)the Top Leading Talents Project of Gansu Province,the Key R&D program of Gansu Province(No.21YF5GA066)+1 种基金Gansu Province College Industry Support Plan Project(No.2022CYZC-18)Natural Science Foundation of Gansu Province(Nos.2020-0405-JCC-630,20JR10RA088).
文摘Hydrazine hydrate(DH)is an important fine chemical intermediate and as fuel for rockets,however,it also has serious toxic for humans and environment.Developing novel materials and methods for sensitive detection of DH in water and air is an important task.In order to effectively detect DH,a novel conductive supramolecular polymer metallogel(PQ-Ag)has been constructed by the coordination of bis-5-hydroxyquinoline functionalized pillar[5]arene(PQ5)with Ag+.The metallogel PQ-Ag could realize the multi-channel sensitive detection of DH through naked-eye,fluorescence,and electrochemical methods.The lowest limit of detection(LOD)is 0.1 mg/m^(3)in air and 2.68×10^(−8)mol/L in water,which is lower than the standard of the US Environmental Protection Agency(EPA)for DH of maximum allowable concentration in drinking water.More importantly,an electronic device for DH detection based on the metallogel PQ-Ag was designed and prepared,which can realize conveniently and efficiently multi-channel detection and alert of DH through sound and light alarms not only in water but also in air.
基金supported by the National Natural Science Foundation of China(No.22090050,No.22090052,No.22176180)National Basic Research Program of China(No.2021YFA1200400)+1 种基金the Natural Science Foundation of Hubei Province(No.2024AFA001)Shenzhen Science and Technology Program(No.JCYJ20220530162406014)。
文摘Strontium-90,a highly radioactive isotope,accumulates within the food chain and skeletal structure,posing significant risks to human health.There is a critical need for a sensitive detection strategy for Strontium-90 in complex environmental samples.Here,solid-state nanochannels,modified with metal-organic frameworks(MOF)and specific aptamers,were engineered for highly sensitive detection of strontium ion(Sr^(2+)).The synergistic effect between the reduced effective diameter of the nanochannels due to MOF and the specific binding of Sr^(2+) by aptamers amplifies the difference in ionic current signals,enhancing detection sensitivity significantly.The MOF-modified nanochannels exhibit highly sensitive detection of Sr^(2+),with a limit of detection(LOD)being 0.03 nmol·L^(-1),whereas the LOD for anodized aluminum oxide(AAO)without the modified MOF nanosheets is only 1000 nmol·L^(-1).These findings indicate that the LOD of Sr^(2+) detected by the MOF-modified nanochannels is approximately 33,000 times higher than that by the nanochannels without MOF modification.Additionally,the highly reliable detection of Sr^(2+) in various water samples was achieved,with a recovery rate ranging from 94.00%to 118.70%.This study provides valuable insights into the rapidly advancing field of advanced nanochannel-based sensors and their diverse applications for analyzing complex samples,including environmental contaminant detection,food analysis,medical diagnostics,and more.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61078005)the National Basic ResearchProgram of China (Grant No. 2007CB613205)the China Postdoctoral Science Foundation
文摘Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO：LiNbO 3 crystals pumped at 1.064 μm.The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm,corresponding to a pumpto-idler photon conversion efficiency of 25%.By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region,one can measure very week mid-infrared radiation with ordinary detectors,which are insensitive to mid-infrared radiation,with a very high gain.A maximum gain factor of about 7 脳 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse.
文摘A simple technique for sensitive detection of heroine based on surface- plasmonresonance has been theoretically and experimentally investigated. The experiment was realized by using an anti-MO monoclonal antibody and a morphine (MO)-bovine serum albumin (MOBSA) conjugate (antigen). The reason for using MO-BSA in the detection of heroine was also discussed. MO-BSA was immobilized on a gold thin film of SPR sensor chip by physical adsorption. The configuration of the device is allowed to be further miniaturized, which is required for the construction of a portable SPR device in the application of in-situ analysis.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0400104 and2016YFB0400301the National Natural Sciences Foundation of China under Grant No 61334002the National Science and Technology Major Project
文摘Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid （DNA） hybridization. The Au-gated AIInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current （VDS = 0.5 V） shows a clear decrease of 69μA upon the introduction of 1μmolL^-1 （μM） complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.
基金supported by National Key R&D Program of China under Grants No.2022YFB3902500,No.2022YFB2903402,and No.2021YFA0718804Natural Science Foundation of Jilin Province under Grant No.222621JC010297013Education Department of Jilin Province under Grant No.JJKH20220745KJ.
文摘Optical wireless(OW)communication systems face significant challenges such as signal attenuation due to atmospheric absorption,scattering,and noise from hardware components,which degrade detection sensitivity.To address these challenges,we propose a digital processing algorithm that combines finite impulse response filtering with dynamic synchronization based on pulse addition and subtraction.Unlike conventional methods,which typically rely solely on hardware optimization or basic thresholding techniques,the proposed approach integrates filtering and synchronization to improve weak signal detection and reduce noise-induced errors.The proposed algorithm was implemented and verified using a field-programmable gate array.Experiments conducted in an indoor OW communication environment demonstrate that the proposed algorithm significantly improves detection sensitivity by approximately 6 dB and 5 dB at communication rates of 3.5 Mbps and 5.0 Mbps,respectively.Specifically,under darkroom conditions and a bit error rate of 1×10^(-7),the detection sensitivity was improved from-38.56 dBm to-44.77 dBm at 3.5 Mbps and from-37.12 dBm to-42.29 dBm at 5 Mbps.The proposed algorithm is crucial for future capture and tracking of signals at large dispersion angles and in underwater and long-distance communication scenarios.
基金supported by the Project of tacking of key scientifi c and technical problems in Henan Province(192102310033)。
文摘This study employs an N-carboxyanhydride ring-opening polymerization(NCA ROP)signal amplification strategy to construct a novel sensing system for the simple and rapid detection of tobacco mosaic virus RNA(tRNA).In the developed fluorescent biosensor,carboxylated biomagnetic beads serve as carriers for target capture based on the complementary pairing of the aptamer bases.Subsequently,NCA ROP fluorescent peptides are utilized as highly biocompatible signal carriers to achieve sensitive detection of the target.Under the optimal conditions,the biosensor exhibits a broad linear detection range from 1 pM to 10 nM,with a detection limit as low as 0.085 pM.Furthermore,the fluorescent aptamer biosensor demonstrates robust affinity and reliability in recovery experiments involving healthy R ehmannia glutinosa leaf total RNA.This work establishes a robust platform for tRNA analysis,facilitating real-time and early diagnosis of various plant viruses.
文摘Prunus necrotic ring spot virus （PNRSV） and grapevine fanleaf virus （GFLV） were detected by fluoroimmunoassay using bacterial magnetic particles （BMPs）, and a double antibody sandwich enzyme linked immunosorbent assay （DAS-ELISA）. For the fluoroimmunoassay, fluorescein isothiocyanate labeled anti-PNRSV antibody or anti-GFLV antibody was conjugated onto BMPs of Magnetospirillum gryphiswaldense MSR-1. With this method, a very low minimum antigen concentration （1×10^6 dilution of the original sample concentration） could be detected. Using DAS-ELISA, the minimum antigen detection concentration was the original sample concentration. Thus, comparing these two methods, a BMP-based method could increase the sensitivity up to six orders of magnitude （10^6） higher than an ELISA-based method of detection PNRSV and GFLV.
基金supported by the National Natural Science Foundation of China (No.21674102)
文摘In this work, a binary-mixed-brushes-coated (BBC) capillary with switchable protein adsorption/desorption properties was developed and applied for on-line preconcentration of proteins. Firstly, amine-terminated poly(2-methyl-2-oxazoline)(PMOXA-NH2) and thiolterminated poly(acrylic acid)(PAA-SH) were synthesized by using cationic ring-opening polymerization (CROP) and reversible addition fragmentation chain transfer (RAFT) polymerization, respectively. Then, the BBC capillary based on poly(2-methyl-2-oxazoline)(PMOXA) and poly(acrylic acid)(PAA) was prepared by sequentially grafting of PMOXA-NH2 and PAA-SH onto fused-silica capillary inner surface through poly(dopamine)(PDA) as an anchor. The obtained PMOXA/PAA coating formed on the capillary or capillary's raw material was characterized in terms of the thickness, surface chemical composition by using scanning electron microscope (SEM) and X-ray photoelectron spectrum (XPS). The switchable protein adsorption/desorption performance of the BBC capillary was investigated by using fluorescence microscope under di erent solutions with certain pH and ionic strength(I). The results showed that bovine serum albumin (BSA) could be adsorbed on BBC capillary at pH=5.0 (I=10^-5 mol/L), and then the adsorbed BSA could be released at pH=9.0 (I=0.1 mol/L). This switchable protein adsorption/desorption property of coated capillary was then used to preconcentrate proteins on-line for increasing the detection sensitivity of BSA in capillary electrophoresis (CE). With this method, a sensitivity enhancement factor (SEF) more than 5000 for BSA detection was obtained.
基金supported by the National Science Foundation of China(NSFC)(52075162)the Program of New and High-Tech Industry of Hunan Province(2020GK2015 and 2021GK4014)+5 种基金the Excellent Youth Fund of Hunan Province(2021JJ20018)the Key Program of Guangdong(2020B0101040002)the Joint Fund of the Ministry of Education(Young Talents)the Natural Science Foundation of Changsha(kq2007026)the Tianjin Enterprise Science and Technology Commissioner Project(19JCTPJC56200)the Engineering Physics and Science Research Council of the United Kingdom(EPSRC EP/P018998/1).
文摘Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequencies of SAW devices are typically limited to within a few gigahertz, which severely restricts their applications in 5G communication, precision sensing, photonics, and quantum control. To solve this critical problem, we propose a hybrid strategy that integrates a nanomanufacturing process (i.e., nanolithography) with a LiNbO_(3)/SiO_(2)/SiC heterostructure and successfully achieve a record-breaking frequency of about 44 GHz for SAW devices, in addition to large electromechanical coupling coefficients of up to 15.7%. We perform a theoretical analysis and identify the guided higher order wave modes generated on these slow-on-fast SAW platforms. To demonstrate the superior sensing performance of the proposed ultra-high-frequency SAW platforms, we perform micro-mass sensing and obtain an extremely high sensitivity of approximately 33151.9 MHz·mm2·μg−1, which is about 1011 times higher than that of a conventional quartz crystal microbalance (QCM) and about 4000 times higher than that of a conventional SAW device with a frequency of 978 MHz.
