Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti...Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.展开更多
Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.Howev...Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.展开更多
Micro thermoelectric device(μ-TED)emerges with great attention in energy generation,thermal management,and heat sensing applications.However,the large sensitive area is necessary to accommodate enough thermoelectric ...Micro thermoelectric device(μ-TED)emerges with great attention in energy generation,thermal management,and heat sensing applications.However,the large sensitive area is necessary to accommodate enough thermoelectric couples(TCs)for a high thermoelectric performance.This limits the potential in micro energy harvesting and ultrasensitive sensing applications.Here,we adopted an optimized MEMS-based process to fabricate the ultra-sensitive micro-thermoelectric device(μ-TED).With the help of MEMS-compatible electrochemical deposition,the small size(25μm),high aspect ratio(1:1.25),and alternating distributed P/N structures are achieved.As a result,theμ-TED realizes an ultra-high integration density of 19,900 thermoelectric couples per cm2.Moreover,it shows a great thermoelectric sensitivity of 212 mV/(K·cm2)and a competitive power factor of 0.51μW/(K2·cm2),which means theμ-TED is competent for miniaturized applications.Additionally,theμ-TED shows an ultra-low detection limit of 5 mm/s and a short response time of 100 ms,revealing great potential in fast detections of the ultra-low airflow.Furthermore,the ultra-sensitiveμ-TED is utilized as a flexible breath sensor,due to its compact size.The breath signal of different motion states is successfully detected.These results confirm that the ultra-sensitiveμ-TED holds outstanding potential for ultra-sensitive airflow sensing and energy harvesting devices.展开更多
Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications.Two-dimensional(2D)hybrid perovskite ferroelectrics,in which the coupling of spontaneous polar...Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications.Two-dimensional(2D)hybrid perovskite ferroelectrics,in which the coupling of spontaneous polarization(P_(s))and light favors the dissociation of photo-induced carriers,have taken a booming position within this portfolio.However,polarized-light photodetectors with a low detectionlimit remain unexplored in this 2D ferroelectric family.In this work,the high-quality individual crystals of a 2D perovskite ferroelectric,BA_(2)CsPb_(2)Br_(7)(1,where BA^(+)is n-butylammonium),were used to fabricate ultrasensitive polarized-light detectors.Its unique bilayered structural motif results in quite strong electric and optical anisotropy with a large absorption ratio of a_(c)/α_(a)≈3.2(λ=405 nm).Besides,the presence of ferroelectric Psalso endows high built-in electric field along the polar c-axis that favors photoelectric activities.Under an extremely low detectable limit of 40 n W/cm^(2),the detector of 1 exhibits a notable dichroism ratio(I_(ph)^(c)/I_(ph)^(a)≈1.5),a large responsivity of~39.5 m A/W and a specific detectivity of~1.2×10^(12)Jones.Moreover,crystal-based devices of 1 also exhibit a fast response speed(~300μs)and excellent anti-fatigue merits.This work highlights great potentials of hybrid perovskite ferroelectrics toward polarized-light photodetection.展开更多
Based on chaotic oscillator system, this paper proposes a novel method on high frequency low signal- to-noise ratio BPSK（ Binary Phase Shift Keying） signal detection. Chaotic oscillator system is a typical non-lin- ...Based on chaotic oscillator system, this paper proposes a novel method on high frequency low signal- to-noise ratio BPSK（ Binary Phase Shift Keying） signal detection. Chaotic oscillator system is a typical non-lin- ear system which is sensitive to periodic signals and immune to noise at the same time. Those properties make it possible to detect low signal-to-noise ratio signals. The BPSK signal is a common signal type which is widely used in modern communication. Starting from the analysis of advantages of chaotic, os~.illator system and signal features of the BPSK signal, we put forward a unique method that can detect low signar-to-noise ratio BPSK sig- nals with high frequency. The simulation results show that the novel method can dclct.t low signal-to-noise ratio BPSK signals with frequency in an order of magnitude of l0s Hz, and the input Signal-to-Noise Ratio threshold can be -20 dB.展开更多
This paper proposes the alternating direction method of multipliers-based infinity-norm(ADMIN) with threshold(ADMIN-T) and with percentage(ADMIN-P) detection algorithms,which make full use of the distribution of the s...This paper proposes the alternating direction method of multipliers-based infinity-norm(ADMIN) with threshold(ADMIN-T) and with percentage(ADMIN-P) detection algorithms,which make full use of the distribution of the signal to interference plus noise ratio(SINR) for an uplink massive MIMO system.The ADMIN-T and ADMIN-P detection algorithms are improved visions of the ADMIN detection algorithm,in which an appropriate SINR threshold in the ADMIN-T detection algorithm and a certain percentage in the ADMIN-P detection algorithm are designed to reduce the overall computational complexity.The detected symbols are divided into two parts by the SINR threshold which is based on the cumulative probability density function(CDF) of SINR and a percentage,respectively.The symbols in higher SINR part are detected by MMSE.The interference of these symbols is then cancelled by successive interference cancellation(SIC).Afterwards the remaining symbols with low SINR are iteratively detected by ADMIN.The simulation results show that the ADMIIN-T and the ADMIN-P detection algorithms provide a significant performance gain compared with some recently proposed detection algorithms.In addition,the computational complexity of ADMIN-T and ADMIN-P are significantly reduced.Furthermore,in the case of same number of transceiver antennas,the proposed algorithms have a higher performance compared with the case of asymmetric transceiver antennas.展开更多
Cysteine(Cys)plays a pivotal role in many physiological and pathological processes,including detoxification and protein synthesis.The abnormal levels of Cys are linked to many diseases.In this study,a novel red-emitti...Cysteine(Cys)plays a pivotal role in many physiological and pathological processes,including detoxification and protein synthesis.The abnormal levels of Cys are linked to many diseases.In this study,a novel red-emitting off-on fluorescent probe Cys-TCF was masterly constructed for discriminative detection of Cys.After a series of experimental assessment,Cys-TCF displayed higher selectivity and sensitivity for Cys over other biothilols with a low detection limit(0.04μmol/L).More notably,the probe was also successfully applied to image Cys in live cells and live zebrafishes with low cytotoxicity.展开更多
Ethylene(C2 H4),as a plant hormone,its emission can be served as an indicator to measure fruit quality.Due to the limited physiochemical reactivity of C2 H4,it is a challenge to develop high performance C2 H4 sensors ...Ethylene(C2 H4),as a plant hormone,its emission can be served as an indicator to measure fruit quality.Due to the limited physiochemical reactivity of C2 H4,it is a challenge to develop high performance C2 H4 sensors for fruit detection.Herein,this paper presents a resistive-type C2 H4 sensor based on Pd-loaded tin oxide(SnO2).The C2 H4 sensing performance of proposed sensor are tested at optimum operating temperature(250℃)with ambient relative humidity(51.9%RH).The results show that the response of Pd-loaded SnO2 sensor(11.1,Ra/Rg)is about 3 times higher than that of pristine SnO2(3.5)for 100 ppm C2 H4.The response time is also significantly shortened from 7 s to 1 s compared with pristine SnO2.Especially,the Pd-loaded SnO2 sensor possesses good sensitivity(0.58 ppm 1)at low concentration(0.05-1 ppm)with excellent linearity(R2=0.9963)and low detection limit(50 ppb).The high sensing performance of Pd-loaded SnO2 are attributed to the excellent adsorption and catalysis effects of Pd nanoparticle.Meaningfully,the potential applications of C2 H4 sensor are performed for monitoring the maturity and freshness of fruits,which presents a promising prospect in fruit quality evaluation.展开更多
Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydr...Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.展开更多
The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method ...The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method to detect and degrade phenolic compounds.Herein,we report a new keggin-type polyoxometallate-based metal-organic complex self-assembled under solvothermal condition,{[Cu(dap)(3-PA)]4(SiW_(12)O_(40))(H_(2)O)_(2)}·2H_(2)O(1,dap=1,2-diaminopropane,3-HPA=3-pyridineacrylic acid).1 shows an interesting 1D ladder-like structure.As a bifunctional catalyst,1 can be employed as a colori-metric sensor toward phenol with the relatively low detection limit(LOD)of 0.36μmol/L(S/N=3)in the wide range(0.001-0.1 mmol/L).The title colorimetric sensor is applied to determine phenol in various water environment with good recoveries ranging from 95%-105%.In addition,1 also exhibits excellent photocatalytic degradation toward phenol under visible light with the highest removal efficiency at 96%for 100 min and wide pH universality.The selectivity,stability and reliability of the detection of 1 towards phenol,as well as the detection for 4-chlorophenol,o-cresol,4-nitrophenol and phloroglucinol were stud-ied.Furthermore,the photocatalytic reaction kinetics and the mechanisms of photodegradation of phenol were also investigated in detail.展开更多
The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and s...The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors.The weight and thickness of X-ray detectors can be reduced by replacing the silicon layer with an organic photodetectors.This study presents a novel bithienopyrroledione-based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer(~700 nm),owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione.The ability of bithienopyrroledione-based polymer donor to strongly suppress the dark current density(Jd~10−10 A cm^(−2))at a negative bias(−2.0 V)while maintaining high responsivity(R=0.29 A W−1)even at a thickness of 700 nm results in a maximum shot-noise-limited specific detectivity of D_(sh)^(*)=2.18×10^(13)Jones in the organic photodetectors.Printed organic photodetectors are developed by slot-die coating for use in X-ray detectors,which exhibit D_(sh)^(*)=2.73×10^(12)Jones with clear rising(0.26 s)and falling(0.29 s)response times upon X-ray irradiation.Detection reliability is also proven by linear response of the X-ray detector,and the X-ray detection limit is 3 mA.展开更多
To utilizing the characteristic of radar cross section （RCS） of the low detectable aircraft, a special path planning algorithm to eluding radars by the variable RCS is presented. The algorithm first gives the RCS ch...To utilizing the characteristic of radar cross section （RCS） of the low detectable aircraft, a special path planning algorithm to eluding radars by the variable RCS is presented. The algorithm first gives the RCS changing model of low detectable aircraft, then establishes a threat model of a ground-based air defense system according to the relations between RCS and the radar range coverage. By the new cost functions of the flight path, which consider both factors of the survival probability and the distance of total route, this path planning method is simulated based on the Dijkstra algorithm, and the planned route meets the flight capacity constraints. Simulation results show that using the effective path planning algorithm, the low detectable aircraft can give full play to its own advantage of stealth to achieve the purpose of silent penetration.展开更多
A new solid-contact Ag~＋-selective electrode was prepared with 9,10,12,13,24,25-hexahydro-5H,15H,23H-dibenzo [b,q][1,7,10,13,19,4,16]-entathiadiazacyclodocosine-6,16（7H,17H）-dione as ionophore,and cc,a-dihexylsexit...A new solid-contact Ag~＋-selective electrode was prepared with 9,10,12,13,24,25-hexahydro-5H,15H,23H-dibenzo [b,q][1,7,10,13,19,4,16]-entathiadiazacyclodocosine-6,16（7H,17H）-dione as ionophore,and cc,a-dihexylsexithiophene（DH- 6T） ion-to-electron transducer.The sensor exhibited a working concentration range of 10~8 to 10^（-3） mol/L,with a near-Nernstian slope of 55.1±0.2 mV/dec and detection limit of 1.7×10^（-9） mol/L.The fabricated electrodes demonstrated excellent selectivity over the most common monovalent and divalent cations.展开更多
Background Low tuberculosis(TB)case detection remains a major challenge in achieving the End TB targets.New strategies that consider local contexts are needed in countries with high TB burdens like Ethiopia.This study...Background Low tuberculosis(TB)case detection remains a major challenge in achieving the End TB targets.New strategies that consider local contexts are needed in countries with high TB burdens like Ethiopia.This study exam-ined the effect of integrating traditional and modern TB care to increase the TB case detection rate.Methods A cluster randomized controlled trial was conducted from February 2023 to January 2024 in six districts of South Gondar Zone,Northwest Ethiopia,where districts were randomly assigned to intervention or control groups.The interventions included training,screening,and referral of presumptive TB patients,delivered over one year,while the control group continued with the standard passive case detection approach.A paired t-test and two sample independent t-test were used to compare baseline and end line data for both groups.Cohen's d was also used to compare the effect size between the intervention and the control groups.A mixed-effect Poisson regression was employed to determine the association between the dependent variable and the exposure variables.Results In the intervention group,a total of 620 TB cases were identified post-intervention,compared with 473 cases pre-intervention,including 14 cases identified through referrals by traditional care providers.In contrast,the control group identified 298 TB cases post-intervention and 279 pre-intervention.The TB detection rate increased to 93 cases per 100,000 population in the intervention group,making an approximate 29.2%improvement,compared to a 2.9%increase in the control group.Integrating traditional care with the modern healthcare system significantly increased case detection,with a standardized mean difference of 2.6(95%confidence interval CI:1.8,3.5;t=8.3;P<0.001)in a two-sample independent t-test.Conclusions Integrating traditional care with the modern healthcare system significantly increased TB case detec-tion in high-burden settings.This approach not only enhances current TB control strategies but also has potential applications in managing other chronic diseases in resource-limited areas.Future research should evaluate the cost-effectiveness,scalability,and sustainability of this integrative model.Trial registration Unique Protocol ID:353/2021.ClinicalTrials.gov ID:NCT05236452.The date recruitment began:July 1,2022.Registration date:July 22,2022.展开更多
A new fluorescent probe RY was synthesized for the detection of Au3+ions based on a rhodamine B derivative.The fluorescent probe showed good selectivity and sensitivity to Au3+ions.Obvious color and fluorescence chang...A new fluorescent probe RY was synthesized for the detection of Au3+ions based on a rhodamine B derivative.The fluorescent probe showed good selectivity and sensitivity to Au3+ions.Obvious color and fluorescence changes could be observed with the naked eye while the fluorescent probe reacted with the Au3+ions.The detection limit of the probe was determined to be 36 ppb by the fluorescence titration.The excellent linear relationship suggests that the probe is potentially useful for quantitative detection of Au3+in vitro.We also demonstrated its bioimaging application in both living cells and mice.This was the first time that a fluorescent probe was successfully applied to imaging Au3+in living animals.展开更多
In this work,pure SnO_(2) and Ni-doped SnO_(2) nanorods were synthesized through a one-step template-free hydrothermal method and then used to detect isopropanol.Sensors fabricated with the Ni-doped SnO_(2) nanocompos...In this work,pure SnO_(2) and Ni-doped SnO_(2) nanorods were synthesized through a one-step template-free hydrothermal method and then used to detect isopropanol.Sensors fabricated with the Ni-doped SnO_(2) nanocomposites showed the best gas sensing performance when the Ni doping amount was 1.5 mol.%.The response reached 250 at 225℃,which was approximately 8.3 times higher than that of the pure SnO_(2) nanorods.The limit of detection for isopropanol was as low as 10 ppb at the optimum working temperature.In addition,it also displayed good selectivity and excellent reproducibility.It is believed that the enhanced isopropanol sensing behavior benefit from the increased oxygen defects and larger specific surface area by Ni doping.展开更多
基金the National Key R&D Program of China(No.2023YFB3210102).
文摘Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.
基金financially supported by the National Natural Science Foundation of China(62274103 and 51972194)the National Key Research and Development Program of China(2022YFB3204101)the 111 Project 2.0(BP2018013)。
文摘Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.
基金supported by the Project(NO.62502010320)the National Key Research and Development Program of China(2020YFB2009102).
文摘Micro thermoelectric device(μ-TED)emerges with great attention in energy generation,thermal management,and heat sensing applications.However,the large sensitive area is necessary to accommodate enough thermoelectric couples(TCs)for a high thermoelectric performance.This limits the potential in micro energy harvesting and ultrasensitive sensing applications.Here,we adopted an optimized MEMS-based process to fabricate the ultra-sensitive micro-thermoelectric device(μ-TED).With the help of MEMS-compatible electrochemical deposition,the small size(25μm),high aspect ratio(1:1.25),and alternating distributed P/N structures are achieved.As a result,theμ-TED realizes an ultra-high integration density of 19,900 thermoelectric couples per cm2.Moreover,it shows a great thermoelectric sensitivity of 212 mV/(K·cm2)and a competitive power factor of 0.51μW/(K2·cm2),which means theμ-TED is competent for miniaturized applications.Additionally,theμ-TED shows an ultra-low detection limit of 5 mm/s and a short response time of 100 ms,revealing great potential in fast detections of the ultra-low airflow.Furthermore,the ultra-sensitiveμ-TED is utilized as a flexible breath sensor,due to its compact size.The breath signal of different motion states is successfully detected.These results confirm that the ultra-sensitiveμ-TED holds outstanding potential for ultra-sensitive airflow sensing and energy harvesting devices.
基金supported by the National Natural Science Foundation of China(21622108,21875251,21525104,and 21833010)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20010200)Youth Innovation Promotion of Chinese Academy of Sciences。
文摘Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications.Two-dimensional(2D)hybrid perovskite ferroelectrics,in which the coupling of spontaneous polarization(P_(s))and light favors the dissociation of photo-induced carriers,have taken a booming position within this portfolio.However,polarized-light photodetectors with a low detectionlimit remain unexplored in this 2D ferroelectric family.In this work,the high-quality individual crystals of a 2D perovskite ferroelectric,BA_(2)CsPb_(2)Br_(7)(1,where BA^(+)is n-butylammonium),were used to fabricate ultrasensitive polarized-light detectors.Its unique bilayered structural motif results in quite strong electric and optical anisotropy with a large absorption ratio of a_(c)/α_(a)≈3.2(λ=405 nm).Besides,the presence of ferroelectric Psalso endows high built-in electric field along the polar c-axis that favors photoelectric activities.Under an extremely low detectable limit of 40 n W/cm^(2),the detector of 1 exhibits a notable dichroism ratio(I_(ph)^(c)/I_(ph)^(a)≈1.5),a large responsivity of~39.5 m A/W and a specific detectivity of~1.2×10^(12)Jones.Moreover,crystal-based devices of 1 also exhibit a fast response speed(~300μs)and excellent anti-fatigue merits.This work highlights great potentials of hybrid perovskite ferroelectrics toward polarized-light photodetection.
文摘Based on chaotic oscillator system, this paper proposes a novel method on high frequency low signal- to-noise ratio BPSK（ Binary Phase Shift Keying） signal detection. Chaotic oscillator system is a typical non-lin- ear system which is sensitive to periodic signals and immune to noise at the same time. Those properties make it possible to detect low signal-to-noise ratio signals. The BPSK signal is a common signal type which is widely used in modern communication. Starting from the analysis of advantages of chaotic, os~.illator system and signal features of the BPSK signal, we put forward a unique method that can detect low signar-to-noise ratio BPSK sig- nals with high frequency. The simulation results show that the novel method can dclct.t low signal-to-noise ratio BPSK signals with frequency in an order of magnitude of l0s Hz, and the input Signal-to-Noise Ratio threshold can be -20 dB.
基金This work was supported in part by the National Natural Science Foundation of China(NSFC)under grant numbers 61671047,61775015 and U2006217.
文摘This paper proposes the alternating direction method of multipliers-based infinity-norm(ADMIN) with threshold(ADMIN-T) and with percentage(ADMIN-P) detection algorithms,which make full use of the distribution of the signal to interference plus noise ratio(SINR) for an uplink massive MIMO system.The ADMIN-T and ADMIN-P detection algorithms are improved visions of the ADMIN detection algorithm,in which an appropriate SINR threshold in the ADMIN-T detection algorithm and a certain percentage in the ADMIN-P detection algorithm are designed to reduce the overall computational complexity.The detected symbols are divided into two parts by the SINR threshold which is based on the cumulative probability density function(CDF) of SINR and a percentage,respectively.The symbols in higher SINR part are detected by MMSE.The interference of these symbols is then cancelled by successive interference cancellation(SIC).Afterwards the remaining symbols with low SINR are iteratively detected by ADMIN.The simulation results show that the ADMIIN-T and the ADMIN-P detection algorithms provide a significant performance gain compared with some recently proposed detection algorithms.In addition,the computational complexity of ADMIN-T and ADMIN-P are significantly reduced.Furthermore,in the case of same number of transceiver antennas,the proposed algorithms have a higher performance compared with the case of asymmetric transceiver antennas.
基金financial supports from the National Natural Science Foundation of China (Nos.21708017,21572093,21778028)Lanzhou University (the Fundamental Research Funds for the Central Universities,No.lzujbky-2018-64)Natural Science Foundation of Gansu Province (No.17JR5RA193)
文摘Cysteine(Cys)plays a pivotal role in many physiological and pathological processes,including detoxification and protein synthesis.The abnormal levels of Cys are linked to many diseases.In this study,a novel red-emitting off-on fluorescent probe Cys-TCF was masterly constructed for discriminative detection of Cys.After a series of experimental assessment,Cys-TCF displayed higher selectivity and sensitivity for Cys over other biothilols with a low detection limit(0.04μmol/L).More notably,the probe was also successfully applied to image Cys in live cells and live zebrafishes with low cytotoxicity.
基金supported by the National Science Funds for Excellent Young Scholars of China(No.61822106)National Science Funds for Creative Research Groups of China(No.61421002)+1 种基金Natural Science Foundation of China(No.61671115)Central Public-interest Scientific Institution Basal Research Fund(No.Y2019XK18)。
文摘Ethylene(C2 H4),as a plant hormone,its emission can be served as an indicator to measure fruit quality.Due to the limited physiochemical reactivity of C2 H4,it is a challenge to develop high performance C2 H4 sensors for fruit detection.Herein,this paper presents a resistive-type C2 H4 sensor based on Pd-loaded tin oxide(SnO2).The C2 H4 sensing performance of proposed sensor are tested at optimum operating temperature(250℃)with ambient relative humidity(51.9%RH).The results show that the response of Pd-loaded SnO2 sensor(11.1,Ra/Rg)is about 3 times higher than that of pristine SnO2(3.5)for 100 ppm C2 H4.The response time is also significantly shortened from 7 s to 1 s compared with pristine SnO2.Especially,the Pd-loaded SnO2 sensor possesses good sensitivity(0.58 ppm 1)at low concentration(0.05-1 ppm)with excellent linearity(R2=0.9963)and low detection limit(50 ppb).The high sensing performance of Pd-loaded SnO2 are attributed to the excellent adsorption and catalysis effects of Pd nanoparticle.Meaningfully,the potential applications of C2 H4 sensor are performed for monitoring the maturity and freshness of fruits,which presents a promising prospect in fruit quality evaluation.
基金supported by the National Natural Science Foundation of China(Nos.21673039,21573042.21805039,21975044,21971038 and 21922810)the Fujian Provincial Department of Education(No.JAT200077).
文摘Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21901018,21971024,22271021)the Natural Science Foundation and Education Department of Liaoning province(Nos.2022-MS-373,2021-MS-312,LJ2020008).
文摘The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method to detect and degrade phenolic compounds.Herein,we report a new keggin-type polyoxometallate-based metal-organic complex self-assembled under solvothermal condition,{[Cu(dap)(3-PA)]4(SiW_(12)O_(40))(H_(2)O)_(2)}·2H_(2)O(1,dap=1,2-diaminopropane,3-HPA=3-pyridineacrylic acid).1 shows an interesting 1D ladder-like structure.As a bifunctional catalyst,1 can be employed as a colori-metric sensor toward phenol with the relatively low detection limit(LOD)of 0.36μmol/L(S/N=3)in the wide range(0.001-0.1 mmol/L).The title colorimetric sensor is applied to determine phenol in various water environment with good recoveries ranging from 95%-105%.In addition,1 also exhibits excellent photocatalytic degradation toward phenol under visible light with the highest removal efficiency at 96%for 100 min and wide pH universality.The selectivity,stability and reliability of the detection of 1 towards phenol,as well as the detection for 4-chlorophenol,o-cresol,4-nitrophenol and phloroglucinol were stud-ied.Furthermore,the photocatalytic reaction kinetics and the mechanisms of photodegradation of phenol were also investigated in detail.
基金granted by the Korea Research Institute of Chemical Technology(KRICT)of the Republic of Korea(No.2422-10)the National Research Foundation(NRF)(NRF-2021R1C1C2007445 and RS-2023-00280495)of Republic of Korea.
文摘The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors.The weight and thickness of X-ray detectors can be reduced by replacing the silicon layer with an organic photodetectors.This study presents a novel bithienopyrroledione-based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer(~700 nm),owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione.The ability of bithienopyrroledione-based polymer donor to strongly suppress the dark current density(Jd~10−10 A cm^(−2))at a negative bias(−2.0 V)while maintaining high responsivity(R=0.29 A W−1)even at a thickness of 700 nm results in a maximum shot-noise-limited specific detectivity of D_(sh)^(*)=2.18×10^(13)Jones in the organic photodetectors.Printed organic photodetectors are developed by slot-die coating for use in X-ray detectors,which exhibit D_(sh)^(*)=2.73×10^(12)Jones with clear rising(0.26 s)and falling(0.29 s)response times upon X-ray irradiation.Detection reliability is also proven by linear response of the X-ray detector,and the X-ray detection limit is 3 mA.
文摘To utilizing the characteristic of radar cross section （RCS） of the low detectable aircraft, a special path planning algorithm to eluding radars by the variable RCS is presented. The algorithm first gives the RCS changing model of low detectable aircraft, then establishes a threat model of a ground-based air defense system according to the relations between RCS and the radar range coverage. By the new cost functions of the flight path, which consider both factors of the survival probability and the distance of total route, this path planning method is simulated based on the Dijkstra algorithm, and the planned route meets the flight capacity constraints. Simulation results show that using the effective path planning algorithm, the low detectable aircraft can give full play to its own advantage of stealth to achieve the purpose of silent penetration.
基金financially supported by the National Natural Science Foundation of China(No.21107134)Chinese Academy of Sciences(No.KZCX2-YW-JS208)+1 种基金the Natural Science Foundation of Shandong Province (JQ200814)the Taishan Scholar Program of Shandong Province
文摘A new solid-contact Ag~＋-selective electrode was prepared with 9,10,12,13,24,25-hexahydro-5H,15H,23H-dibenzo [b,q][1,7,10,13,19,4,16]-entathiadiazacyclodocosine-6,16（7H,17H）-dione as ionophore,and cc,a-dihexylsexithiophene（DH- 6T） ion-to-electron transducer.The sensor exhibited a working concentration range of 10~8 to 10^（-3） mol/L,with a near-Nernstian slope of 55.1±0.2 mV/dec and detection limit of 1.7×10^（-9） mol/L.The fabricated electrodes demonstrated excellent selectivity over the most common monovalent and divalent cations.
文摘Background Low tuberculosis(TB)case detection remains a major challenge in achieving the End TB targets.New strategies that consider local contexts are needed in countries with high TB burdens like Ethiopia.This study exam-ined the effect of integrating traditional and modern TB care to increase the TB case detection rate.Methods A cluster randomized controlled trial was conducted from February 2023 to January 2024 in six districts of South Gondar Zone,Northwest Ethiopia,where districts were randomly assigned to intervention or control groups.The interventions included training,screening,and referral of presumptive TB patients,delivered over one year,while the control group continued with the standard passive case detection approach.A paired t-test and two sample independent t-test were used to compare baseline and end line data for both groups.Cohen's d was also used to compare the effect size between the intervention and the control groups.A mixed-effect Poisson regression was employed to determine the association between the dependent variable and the exposure variables.Results In the intervention group,a total of 620 TB cases were identified post-intervention,compared with 473 cases pre-intervention,including 14 cases identified through referrals by traditional care providers.In contrast,the control group identified 298 TB cases post-intervention and 279 pre-intervention.The TB detection rate increased to 93 cases per 100,000 population in the intervention group,making an approximate 29.2%improvement,compared to a 2.9%increase in the control group.Integrating traditional care with the modern healthcare system significantly increased case detection,with a standardized mean difference of 2.6(95%confidence interval CI:1.8,3.5;t=8.3;P<0.001)in a two-sample independent t-test.Conclusions Integrating traditional care with the modern healthcare system significantly increased TB case detec-tion in high-burden settings.This approach not only enhances current TB control strategies but also has potential applications in managing other chronic diseases in resource-limited areas.Future research should evaluate the cost-effectiveness,scalability,and sustainability of this integrative model.Trial registration Unique Protocol ID:353/2021.ClinicalTrials.gov ID:NCT05236452.The date recruitment began:July 1,2022.Registration date:July 22,2022.
基金supported financially by the National Natural Science Foundation of China(21222605,21006009,21136002,21376039)the Fundamental Research Funds for the Central Universities of China+1 种基金the Program for New Century Excellent Talents in Universitythe project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education
文摘A new fluorescent probe RY was synthesized for the detection of Au3+ions based on a rhodamine B derivative.The fluorescent probe showed good selectivity and sensitivity to Au3+ions.Obvious color and fluorescence changes could be observed with the naked eye while the fluorescent probe reacted with the Au3+ions.The detection limit of the probe was determined to be 36 ppb by the fluorescence titration.The excellent linear relationship suggests that the probe is potentially useful for quantitative detection of Au3+in vitro.We also demonstrated its bioimaging application in both living cells and mice.This was the first time that a fluorescent probe was successfully applied to imaging Au3+in living animals.
基金This work was supported by the 12th Graduate Innovative Fund of Wuhan Institute of Technology(Grant No.CX2020269)。
文摘In this work,pure SnO_(2) and Ni-doped SnO_(2) nanorods were synthesized through a one-step template-free hydrothermal method and then used to detect isopropanol.Sensors fabricated with the Ni-doped SnO_(2) nanocomposites showed the best gas sensing performance when the Ni doping amount was 1.5 mol.%.The response reached 250 at 225℃,which was approximately 8.3 times higher than that of the pure SnO_(2) nanorods.The limit of detection for isopropanol was as low as 10 ppb at the optimum working temperature.In addition,it also displayed good selectivity and excellent reproducibility.It is believed that the enhanced isopropanol sensing behavior benefit from the increased oxygen defects and larger specific surface area by Ni doping.
