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Flexible bipyramid-AuNPs based SERS tape sensing strategy for detecting methyl parathion on vegetable and fruit surface
摘要： In present study, a simple and effective surface enhanced Raman scattering (SERS) tape sensing strategy based on bipyramid gold nanoparticles (BP-AuNPs) was developed for sensitive and selective monitoring of methyl parathion residues on vegetable and fruit surface through a simple sampling-and-detection procedure. BP-AuNPs were synthesized by a seed meditated method and systematically characterized using transmission electron microscope (TEM), UV-vis spectrometer, selected area electron diffraction (SAED) and X-Ray diffraction (XRD). The as-synthesized BP-AuNPs showed excellent Raman enhancement effect because their sharp ends provide high electric field enhancement, as revealed by electrodynamic simulations. Also the localized plasmon resonance of the BP-AuNPs matches well with the NIR (785 nm) laser of portable Raman spectrometer, thus maximizing the Raman signal. Two standard SERS probe molecules Rhodamine 6G (R6G) and crystal violet (CV) were first used to prove the effective SERS detection on the model solid (silicon) surface using the BP-AuNPs based tape sensing strategy. The SERS sensor was then applied to detect methyl parathion on surface of cucumbers, tomatoes and apples. A detection limit of ng/cm2 level was easily achieved. The studies have demonstrated that the BP-AuNPs based SERS tape sensing platform can be potentially used to monitor the trace amount of chemical hazards for food and agricultural safety.
关键词： tape sensor,surface enhanced Raman scattering,methyl parathion,bipyramid gold nanoparticles
更新于2025-09-23 15:23:52
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Facile, rapid one-pot synthesis of multifunctional gold nanoclusters for cell imaging, hydrogen sulfide detection and pH sensing
摘要： In this study, we have developed a facile, rapid one-pot strategy for synthesis of orange fluorescent gold nanoclusters (MBISA–AuNCs) at room temperature by using 2-Mercapto-5-benzimidazolesulfonic acid (MBISA) as both reducing and protecting reagent. The prepared AuNCs exhibited prominent advantages including high fluorescent quantum yield, good water solubility, excellent biocompatibility and low toxicity. Based on these superior properties, the AuNCs have been multi-talented applied in cell imaging, hydrogen sulfide detection and pH sensing. Confocal fluorescence imaging showed that the MBISA–AuNCs could enter living cells and distribute in the cytoplasm. Additionally, the obtained AuNCs could visualize H2S fluctuations in living cells without interference of autofluorescence based on their high sensitivity and selectivity detection for H2S with a linear range of 2.7 × 10–11–8.5 × 10?4 M and a detection limit of 0.024 nM. Most strikingly, the AuNCs exhibited strong pH dependent behavior and responded linearly, rapidly and reversibly to minor pH fluctuations within the range of 2.01–12.00. Therefore, the AuNCs could also image pH fluctuations in live cells with negligible autofluorescence and provided a new method of analysis to visualize monitoring wide pH range change in live cells.
关键词： Cell imaging,pH sensor,Gold nanoclusters,Fluorescence,Hydrogen sulfide
更新于2025-09-23 15:23:52
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Sensing Properties of the <I>N</I>,<I>N</I>′-Dipentyl-3,4,9, 10-Perylenedicarboximide Small Molecule for Different Concentrations and Solvents for Sensor Applications
摘要： In present study, optical parameters based on refractive index of the PTCDI-C5 molecule were calculated using the single oscillator model. Also, significant parameters such as long wavelength refractive index, average oscillator wavelength, lattice dielectric constant, ratio of the carrier concentration to the electron effective mass, carrier concentration and electron effective mass of the PTCDI-C5 molecule were obtained. Then, sensing properties of the PTCDI-C5 molecule for different concentrations and volume percents were investigated and the effects of the concentrations and volume percents on sensing parameters were investigated. Then, the optical properties of the solutions of the PTCDI-C5 semiconductor for different solvents were investigated. Finally, these parameters obtained were discussed for sensor applications and this study was compared with the similar and related studies in the literature. PTCDI-C5 can be used in the fabrication of various sensors due to good soluble, optical, sensitivity and response behaviour.
关键词： Wemple DiDomenico Technique,Sensor Applications,PTCDIC5,One Dimensional Organic Nanostructures,Sensing Parameters,Sensitivity
更新于2025-09-23 15:23:52
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Experimental and analytical investigation of LP01-LP11 mode interference
摘要： We introduce an analytical theory of LP01-LP11 mode interference and investigate its application in curvature measurement. Under the weakly guiding condition, an analytical formulation for predicting dip wavelength in the transmission spectrum is proposed. The applicability of the proposed formulation is further explored in terms of curvature measurement based on a few-mode multi-core fiber (FM-MCF). The mechanism of curvature response is analytically presented and verified through numerical simulation and experiments. The comparison of analytical and numerical results is found to be in good agreement when curvature varies from 0 to 1.8 m?1. Meanwhile, a good agreement between the experimental and theoretical values of dip wavelength shift is also observed. Moreover, we find that the temperature effect can be eliminated by using two cores of the FM-MCF during curvature measurement. Through experimental tests, the curvature values are accurately predicted under varying temperatures with maximum error controlled within 6.6%.
关键词： LP01-LP11 mode,Few-mode multi-core fiber (FM-MCF),Mode interference,Temperature,Curvatures sensor
更新于2025-09-23 15:23:52
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CMOS image sensor for high speed and low latency eye tracking
摘要： Eye tracking, or detecting where the user is looking at, is expected as a new type of user interfaces, with including the phenomenon of rapid eye movement, so called saccade. However, real-time tracking of saccade is difficult with the conventional image processing systems for their long processing time and latency against the speed of saccade. In this paper, we describe the design of the CMOS image sensor for eye tracking with high speed and low latency capability, as well as its evaluation results.
关键词： saccade,CMOS image sensor,column parallel architecture,eye tracking
更新于2025-09-23 15:23:52
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Lignosulfonate: a Convenient FRET Platform for the Construction of Ratiometric Fluorescence pH-Sensing Probe
摘要： Lignin is a kind of natural fluorescent polymer material. However, the application based on the fluorescent property of lignin was rarely reported. Herein, a non-covalent lignin-based Fluorescence Resonance Energy Transfer (FRET) system was readily constructed by physical blending method with spirolactam Rhodamine B (SRhB) and lignosulfonate (LS) as the acceptor and donor groups, respectively. The FRET behavior, self-assembly and energy transfer mechanism of SRhB/LS composite were systematically studied. It was demonstrated that LS could be used as a convenient aptamer as energy donor to construct water-soluble ratiometric sensors because of its inherent property of intra-micelle energy transfer cascades. Our results not only presented a facile and general strategy for producing lignin-based functional material, but also provided a fundamental understanding about lignin fluorescent to promote the functional and high-valued applications of lignin fluorescence characteristic.
关键词： lignin,ratiometric sensor,FRET,intra-micelle energy transfer cascade
更新于2025-09-23 15:23:52
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Sensor Fusion and Registration of Lidar and Stereo Camera without Calibration Objects
摘要： Environment perception is an important task for intelligent vehicles applications. Typically, multiple sensors with different characteristics are employed to perceive the environment. To robustly perceive the environment, the information from the different sensors are often integrated or fused. In this article, we propose to perform the sensor fusion and registration of the LIDAR and stereo camera using the particle swarm optimization algorithm, without the aid of any external calibration objects. The proposed algorithm automatically calibrates the sensors and registers the LIDAR range image with the stereo depth image. The registered LIDAR range image functions as the disparity map for the stereo disparity estimation and results in an effective sensor fusion mechanism. Additionally, we perform the image denoising using the modified non-local means filter on the input image during the stereo disparity estimation to improve the robustness, especially at night time. To evaluate our proposed algorithm, the calibration and registration algorithm is compared with baseline algorithms on multiple datasets acquired with varying illuminations. Compared to the baseline algorithms, we show that our proposed algorithm demonstrates better accuracy. We also demonstrate that integrating the LIDAR range image within the stereo’s disparity estimation results in an improved disparity map with significant reduction in the computational complexity.
关键词： stereo camera,LIDAR,sensor fusion
更新于2025-09-23 15:23:52
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Real Time Monitoring of a UV Light-Assisted Biofunctionalization Protocol Using a Nanophotonic Biosensor
摘要： A protocol for the covalent biofunctionalization of silicon-based biosensors using a UV light-induced thiol–ene coupling (TEC) reaction has been developed. This biofunctionalization approach has been used to immobilize half antibodies (hIgG), which have been obtained by means of a tris(2-carboxyethyl)phosphine (TCEP) reduction at the hinge region, to the surface of a vinyl-activated silicon-on-insulator (SOI) nanophotonic sensing chip. The response of the sensing structures within the nanophotonic chip was monitored in real time during the biofunctionalization process, which has allowed us to confirm that the bioconjugation of the thiol-terminated bioreceptors onto the vinyl-activated sensing surface is only initiated upon UV light photocatalysis.
关键词： UV light photocatalysis,biofunctionalization,silicon on insulator,nanophotonic sensor,half antibodies
更新于2025-09-23 15:23:52
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Optimised Performance of Non-Dispersive Infrared Gas Sensors Using Multilayer Thin Film Bandpass Filters
摘要： In this work, performance improvements are described for a low-power consumption non-dispersive infrared (NDIR) methane (CH4) gas sensor using customised optical thin film bandpass filters (BPFs) centered at 3300 nm. BPFs shape the spectral characteristics of the combined mid-infrared III–V based light emitting diode (LED)/photodiode (PD) light source/detector optopair, enhancing the NDIR CH4 sensor performance. The BPFs, deposited using a novel microwave plasma-assisted pulsed DC sputter deposition process, provide room temperature deposition directly onto the temperature-sensitive PD heterostructure. BPFs comprise germanium (Ge) and niobium pentoxide (Nb2O5) alternating high and low refractive index layers, respectively. Two different optical filter designs are progressed with BPF bandwidths (BWs) of 160 and 300 nm. A comparison of the modelled and measured NDIR sensor performance is described, highlighting the maximised signal-to-noise ratio (SNR) and the minimised cross-talk performance benefits. The BPF spectral stability for various environmental temperature and humidity conditions is demonstrated.
关键词： III–V,sensor,methane,thin film,MBE,NDIR,microwave,bandpass,sputter,heterostructure,infrared
更新于2025-09-23 15:23:52
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Highly Sensitive and Selective PbTiO3 Gas Sensors with Negligible Humidity Interference in Ambient Atmosphere
摘要： Three PbTiO3 nanostructures were synthesized using a one-step hydrothermal reaction with different TiO2 powders as Ti sources, and their gas sensing properties were investigated. The sensor comprising PbTiO3 nanoplates exhibited a high response (resistance ratio = 80.4) to 5 ppm ethanol at 300 °C and could detect trace concentrations of ethanol down to 100 ppb. Moreover, the sensor showed high ethanol selectivity and nearly the same sensing characteristics despite the wide range of humidity variation from 20% RH to 80% RH. The mechanism for humidity-independent gas sensing was elucidated using the diffuse reflectance infrared Fourier transform spectra. PbTiO3 nanoplates are new and promising sensing materials that can be used for detecting ethanol in a highly sensitive and selective manner with negligible interference from ambient humidity.
关键词： selectivity,ethanol,PbTiO3 nanoplate,gas sensor,humidity interference
更新于2025-09-23 15:23:52