Submicron scale temperature sensors are crucial for a range of applications,particularly in micro and na-noscale environments.One promising solution involves the use of active whispering gallery mode(WGM)microresonato...Submicron scale temperature sensors are crucial for a range of applications,particularly in micro and na-noscale environments.One promising solution involves the use of active whispering gallery mode(WGM)microresonators.These resonators can be remotely excited and read out using free-space structures,simplifying the process of sensing.In this study,we present a submicron-scale temperature sensor with a remarkable sensitivity up to 185 pm/℃based on a trian-gular MAPbI3 nanoplatelet(NPL)laser.Notably,as temperature changes,the peak wavelength of the laser line shifts lin-early.This unique characteristic allows for precise temperature sensing by tracking the peak wavelength of the NPL laser.The optical modes are confined within the perovskite NPL,which measures just 85 nm in height,due to total internal reflec-tion.Our NPL laser boasts several key features,including a high Q of~2610 and a low laser threshold of about 19.8μJ·cm^(−2).The combination of exceptional sensitivity and ultra-small size makes our WGM device an ideal candidate for integration into systems that demand compact temperature sensors.This advancement paves the way for significant prog-ress in the development of ultrasmall temperature sensors,opening new possibilities across various fields.展开更多
The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of th...The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of the MoOx/AuNPs composite were char-acterized by scan electron microscopy and X-ray photoelectron spectroscopy respectively, and the electrocatalytic oxidation of glucose at the MoOx/AuNPs composite film was inves-tigated and analyzed in detail. It was shown that the MoOx/AuNPs composite was of strong electrocatalytic activity towards oxidation of glucose as well as other saccharides, so that an attempt was made for direct voltammetric determination of glucose. Then the positive scan polarization reverse catalytic voltammetry was proposed for the first time. Based on this method, the pure oxidation current was extracted by subtraction of the blank current in the reverse scan. The current sensitivity was enhanced tremendously and the signal to noise ra-tio was improved adequately. The electrocatalytic oxidation of glucose at the MoOx/AuNPs modified electrode was performed in alkaline medium, a wide linear range from 0.01 mmol/L to 4.0 mmol/L of glucose, a higher current sensitivity of 2.35 mA/（mmol/L·cm2）, and a lower limit of detection of 9.01 μmol/L （at signal/noise=3） were achieved. In addition, the electrocatalytic oxidation of other saccharides such as lactose, fructose and sucrose was also evaluated.展开更多
As an effective and universal acaricide, amitraz is widely used on beehives against varroasis caused by the mite Varroa jacobsoni. Its residues in honey pose a great danger to human health. In this study, a sensitive,...As an effective and universal acaricide, amitraz is widely used on beehives against varroasis caused by the mite Varroa jacobsoni. Its residues in honey pose a great danger to human health. In this study, a sensitive, rapid, and environmentally friendly surface-enhanced Raman spectroscopy method (SERS) was developed for the determination of trace amount of amitraz in honey with the use of silver nanorod (AgNR) array substrate. The AgNR array substrate fabricated by an oblique angle deposition technique exhibited an excellent SERS activity with an enhancement factor of -10^7. Density function theory was employed to assign the characteristic peak of amitraz. The detection of amitraz was further explored and amitraz in honey at concentrations as low as 0.08 mg/kg can be identified. Specifically, partial least square regression analysis was employed to correlate the SERS spectra in full-wavelength with Camitraz to afford a multiple-quantitative amitraz predicting model. Preliminary results show that the predicted concentrations of amitraz in honey samples are in good agreement with their real concentrations. Compared with the conventional univariate quantitative model based on single peak’s intensity, the proposed multiple-quantitative predicting model integrates all the characteristic peaks of amitraz, thus offering an improved detecting accuracy and anti-interference ability.展开更多
A novel technique of immobilizing indicator dyes by electrostatic adsorption and covalent bonding to fabricate optical sensors was developed.3-Amino-9-ethylcarbazole(AEC)was attached to the outmost surface of quartz g...A novel technique of immobilizing indicator dyes by electrostatic adsorption and covalent bonding to fabricate optical sensors was developed.3-Amino-9-ethylcarbazole(AEC)was attached to the outmost surface of quartz glass slide via aminosilanizing the slide,crosslinking chitosan,adsorbing Au nanoparticle,self-assembling HS(CH2)11OH,and coupling AEC.Thus, an AEC-immobilized optical sensor was obtained.The sensor exhibits a wide linear response range from 7.0×10- 7to 1.0×10 -4 mol/L and a correlation coefficient of 0.995 9 for the detection of 2-nitrophenol.The detection limit and response time of the sensor are 1.0×10- 7mol/L and less than 10 s,respectively.The fluorescence intensity of the used sensor can be restored to the blank value by simply rinsing with blank buffer.A very effective matrix for immobilizing indicator dye is provided by the proposed technique, which is adaptable to other indicator dyes with amino groups besides AEC.展开更多
The microstructure and mechanical properties of Mg-xCe-0.5Zn （x=0.5, 1.5, 2.5, molar fraction, %） alloys were examined using a nano-indentation technique. The alloys were fabricated using a vacuum induction melting ...The microstructure and mechanical properties of Mg-xCe-0.5Zn （x=0.5, 1.5, 2.5, molar fraction, %） alloys were examined using a nano-indentation technique. The alloys were fabricated using a vacuum induction melting method under an argon atmosphere The microstruetures of Mg-xCe-0.5Zn alloys mainly consist ofa-Mg and eutectic Mg12Ce phase. The volume fraction and size of the eutectic Mgl2Ce phase increase with increasing Ce contents. Nano-indentation test results show that the indentation hardness and elastic modulus of the eutectic Mg12Ce phase are higher than those of the a-Mg matrix. In addition, the mean indentation hardness and elastic modulus of the Mg-xCe-0.5Zn alloys increase with the Ce addition amount increasing.展开更多
A practical serf-localization scheme for mobile robots is proposed and implemented by utilizing sonar sensors. Specifically, the localization problem is solved by employing Monte Carlo method with a new mechanism prop...A practical serf-localization scheme for mobile robots is proposed and implemented by utilizing sonar sensors. Specifically, the localization problem is solved by employing Monte Carlo method with a new mechanism proposed to calculate the samples＇ weights; the convergence and veracity of the sample set are guaranteed by the designed resampling and scattering process. The proposed serf-localization algorithm is fully implemented on a specific mobile robot system, and experimental results illustrate that it provides an efficient solution for the kidnapped problem.展开更多
A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 5...A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 55 nm were synthesized via the Turkevich method and were then immobilized onto the surface of an uncladded sensor probe using a polydopamine layer. To obtain a sensor probe with high sensitivity to changes in the refractive index, a set of key optimization parameters, including the sensing length, coating time of the potydopamine layer, and coating time of the gold nanoparticles, were investigated. The sensitivity of the optimized sensor probe was 522.80 nm per refractive index unit, and the probe showed distinctive wavelength shifts when the refractive index was changed from 1.328 6 to 1.398 7. When stored in deionized water at 4 ℃, the sensor probe proved to be stable over a period of two weeks. The sensor also exhibited advantages, such as low cost, fast fabrication, and simple optical setup, which indicated its potential application in remote sensing and real-time detection.展开更多
This study aimed to effectively reduce the cracking susceptibility of the laser clad coating by enhancing the environmental temperature during laser cladding,and reveal the residual stress distribution in different de...This study aimed to effectively reduce the cracking susceptibility of the laser clad coating by enhancing the environmental temperature during laser cladding,and reveal the residual stress distribution in different depths of the coating.The TiNi/Ti2Ni-based coatings were prepared on Ti6Al4V by laser cladding at different environmental temperatures of25,400,600and800°C.The changes in residual stress along the depth of the coatings were investigated in detail by the nanoindentation method.Results showed that the average residual stress of2.90GPa in the coating prepared at25°C was largest.With the increase in environmental temperature,the average residual stress was reduced to1.34GPa(400°C),0.70GPa(600°C)and0GPa(800°C).For all the coatings,the residual stress was increased with increasing the distance from the coating surface.Enhancing the environmental temperature can effectively reduce the cracking susceptibility of the coatings.展开更多
Based on the deficiency of catalytic elements in methane sensors such as sintering,activity decrease and surface area reduction at high temperature, three differentnano vectors Ce-Zr-Al_2O_3, Ce-Al_2O_3, and Zr-Al_2O_...Based on the deficiency of catalytic elements in methane sensors such as sintering,activity decrease and surface area reduction at high temperature, three differentnano vectors Ce-Zr-Al_2O_3, Ce-Al_2O_3, and Zr-Al_2O_3 were prepared via sol-gel technique inthe experiment.BET surface area, catalytic activity and thermal stability were tested andcompared.It is found from the experiment that the Ce-doped Al_2O_3 vector possesseshigher catalytic activity than pure Al_2O_3 vector.Zr-doped Al_2O_3 vector can enhance thethermal stability of methane sensors.Ce-Zr-Al solid solution can be obtained by the presenceof Ce and Zr doped with Al_2O_3.The reaction activity and thermal stability of catalyticsensors were improved because of the unique synergy effect from Ce-Zr-O.Among themixed cocatalysts, Ce-Zr-O was reported to be an excellent cocatalyst material.The performanceof methane sensors can be improved significantly via the modification ofCe-Zr-Al_2O_3 vector.展开更多
文摘Submicron scale temperature sensors are crucial for a range of applications,particularly in micro and na-noscale environments.One promising solution involves the use of active whispering gallery mode(WGM)microresonators.These resonators can be remotely excited and read out using free-space structures,simplifying the process of sensing.In this study,we present a submicron-scale temperature sensor with a remarkable sensitivity up to 185 pm/℃based on a trian-gular MAPbI3 nanoplatelet(NPL)laser.Notably,as temperature changes,the peak wavelength of the laser line shifts lin-early.This unique characteristic allows for precise temperature sensing by tracking the peak wavelength of the NPL laser.The optical modes are confined within the perovskite NPL,which measures just 85 nm in height,due to total internal reflec-tion.Our NPL laser boasts several key features,including a high Q of~2610 and a low laser threshold of about 19.8μJ·cm^(−2).The combination of exceptional sensitivity and ultra-small size makes our WGM device an ideal candidate for integration into systems that demand compact temperature sensors.This advancement paves the way for significant prog-ress in the development of ultrasmall temperature sensors,opening new possibilities across various fields.
文摘The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of the MoOx/AuNPs composite were char-acterized by scan electron microscopy and X-ray photoelectron spectroscopy respectively, and the electrocatalytic oxidation of glucose at the MoOx/AuNPs composite film was inves-tigated and analyzed in detail. It was shown that the MoOx/AuNPs composite was of strong electrocatalytic activity towards oxidation of glucose as well as other saccharides, so that an attempt was made for direct voltammetric determination of glucose. Then the positive scan polarization reverse catalytic voltammetry was proposed for the first time. Based on this method, the pure oxidation current was extracted by subtraction of the blank current in the reverse scan. The current sensitivity was enhanced tremendously and the signal to noise ra-tio was improved adequately. The electrocatalytic oxidation of glucose at the MoOx/AuNPs modified electrode was performed in alkaline medium, a wide linear range from 0.01 mmol/L to 4.0 mmol/L of glucose, a higher current sensitivity of 2.35 mA/（mmol/L·cm2）, and a lower limit of detection of 9.01 μmol/L （at signal/noise=3） were achieved. In addition, the electrocatalytic oxidation of other saccharides such as lactose, fructose and sucrose was also evaluated.
基金supported by the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province (No.16KJB510009 and No.17KJB510017)Jiangsu Province Natural Science Foundation of China (BK20150228)
文摘As an effective and universal acaricide, amitraz is widely used on beehives against varroasis caused by the mite Varroa jacobsoni. Its residues in honey pose a great danger to human health. In this study, a sensitive, rapid, and environmentally friendly surface-enhanced Raman spectroscopy method (SERS) was developed for the determination of trace amount of amitraz in honey with the use of silver nanorod (AgNR) array substrate. The AgNR array substrate fabricated by an oblique angle deposition technique exhibited an excellent SERS activity with an enhancement factor of -10^7. Density function theory was employed to assign the characteristic peak of amitraz. The detection of amitraz was further explored and amitraz in honey at concentrations as low as 0.08 mg/kg can be identified. Specifically, partial least square regression analysis was employed to correlate the SERS spectra in full-wavelength with Camitraz to afford a multiple-quantitative amitraz predicting model. Preliminary results show that the predicted concentrations of amitraz in honey samples are in good agreement with their real concentrations. Compared with the conventional univariate quantitative model based on single peak’s intensity, the proposed multiple-quantitative predicting model integrates all the characteristic peaks of amitraz, thus offering an improved detecting accuracy and anti-interference ability.
基金Project(20775010)supported by the National Natural Science Foundation of ChinaProject(208095)supported by the Key Project ofMinistry of Education,China+1 种基金Project(07A006)supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(07JJ3020)supported by Hunan Provincial Natural Science Foundation of China
文摘A novel technique of immobilizing indicator dyes by electrostatic adsorption and covalent bonding to fabricate optical sensors was developed.3-Amino-9-ethylcarbazole(AEC)was attached to the outmost surface of quartz glass slide via aminosilanizing the slide,crosslinking chitosan,adsorbing Au nanoparticle,self-assembling HS(CH2)11OH,and coupling AEC.Thus, an AEC-immobilized optical sensor was obtained.The sensor exhibits a wide linear response range from 7.0×10- 7to 1.0×10 -4 mol/L and a correlation coefficient of 0.995 9 for the detection of 2-nitrophenol.The detection limit and response time of the sensor are 1.0×10- 7mol/L and less than 10 s,respectively.The fluorescence intensity of the used sensor can be restored to the blank value by simply rinsing with blank buffer.A very effective matrix for immobilizing indicator dye is provided by the proposed technique, which is adaptable to other indicator dyes with amino groups besides AEC.
基金supported by a grant-in-aid for the National Core Research Center Program(No.R15-2006-022-02001-0)the Metals Bank project of the Korea Ministry of Knowledge Economy
文摘The microstructure and mechanical properties of Mg-xCe-0.5Zn （x=0.5, 1.5, 2.5, molar fraction, %） alloys were examined using a nano-indentation technique. The alloys were fabricated using a vacuum induction melting method under an argon atmosphere The microstruetures of Mg-xCe-0.5Zn alloys mainly consist ofa-Mg and eutectic Mg12Ce phase. The volume fraction and size of the eutectic Mgl2Ce phase increase with increasing Ce contents. Nano-indentation test results show that the indentation hardness and elastic modulus of the eutectic Mg12Ce phase are higher than those of the a-Mg matrix. In addition, the mean indentation hardness and elastic modulus of the Mg-xCe-0.5Zn alloys increase with the Ce addition amount increasing.
基金Supported by the National Natural Science Foundation of China (No. 60875055)Natural Science Foundation of Tianjin (No. 07JCY-BJC05400)Program for New Century Excellent Talents in University (No. NCET-06-0210)
文摘A practical serf-localization scheme for mobile robots is proposed and implemented by utilizing sonar sensors. Specifically, the localization problem is solved by employing Monte Carlo method with a new mechanism proposed to calculate the samples＇ weights; the convergence and veracity of the sample set are guaranteed by the designed resampling and scattering process. The proposed serf-localization algorithm is fully implemented on a specific mobile robot system, and experimental results illustrate that it provides an efficient solution for the kidnapped problem.
基金Supported by the Ministry of Science and Technology of China(No.2012YQ090194)the National Natural Science Foundation of China(No.51473115)
文摘A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 55 nm were synthesized via the Turkevich method and were then immobilized onto the surface of an uncladded sensor probe using a polydopamine layer. To obtain a sensor probe with high sensitivity to changes in the refractive index, a set of key optimization parameters, including the sensing length, coating time of the potydopamine layer, and coating time of the gold nanoparticles, were investigated. The sensitivity of the optimized sensor probe was 522.80 nm per refractive index unit, and the probe showed distinctive wavelength shifts when the refractive index was changed from 1.328 6 to 1.398 7. When stored in deionized water at 4 ℃, the sensor probe proved to be stable over a period of two weeks. The sensor also exhibited advantages, such as low cost, fast fabrication, and simple optical setup, which indicated its potential application in remote sensing and real-time detection.
基金Project (51471105) supported by the National Natural Science Foundation of ChinaProject (12SG44) supported by the "Shu Guang" Project of Shanghai Municipal Education Commission and Shanghai Education Development Foundation,ChinaProject (15KY0504) supported by the "Graduate Innovation" Project of Shanghai University of Engineering Science,China
文摘This study aimed to effectively reduce the cracking susceptibility of the laser clad coating by enhancing the environmental temperature during laser cladding,and reveal the residual stress distribution in different depths of the coating.The TiNi/Ti2Ni-based coatings were prepared on Ti6Al4V by laser cladding at different environmental temperatures of25,400,600and800°C.The changes in residual stress along the depth of the coatings were investigated in detail by the nanoindentation method.Results showed that the average residual stress of2.90GPa in the coating prepared at25°C was largest.With the increase in environmental temperature,the average residual stress was reduced to1.34GPa(400°C),0.70GPa(600°C)and0GPa(800°C).For all the coatings,the residual stress was increased with increasing the distance from the coating surface.Enhancing the environmental temperature can effectively reduce the cracking susceptibility of the coatings.
基金Supported by the National Natural Science Foundation of China(60910005)
文摘Based on the deficiency of catalytic elements in methane sensors such as sintering,activity decrease and surface area reduction at high temperature, three differentnano vectors Ce-Zr-Al_2O_3, Ce-Al_2O_3, and Zr-Al_2O_3 were prepared via sol-gel technique inthe experiment.BET surface area, catalytic activity and thermal stability were tested andcompared.It is found from the experiment that the Ce-doped Al_2O_3 vector possesseshigher catalytic activity than pure Al_2O_3 vector.Zr-doped Al_2O_3 vector can enhance thethermal stability of methane sensors.Ce-Zr-Al solid solution can be obtained by the presenceof Ce and Zr doped with Al_2O_3.The reaction activity and thermal stability of catalyticsensors were improved because of the unique synergy effect from Ce-Zr-O.Among themixed cocatalysts, Ce-Zr-O was reported to be an excellent cocatalyst material.The performanceof methane sensors can be improved significantly via the modification ofCe-Zr-Al_2O_3 vector.
