- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Crown-Porphyrin Ligand for Optical Sensors Development
摘要： A novel porphyrin ligand, Zn(II)TPP-BPI-crown (ZnPC), functionalized with two dibenzo-crown-ether moieties was synthesized and tested as cation-sensitive ionophore. Fluorescence studies on ligand sensitivity towards a number of different metal cations (Na+, K+, Li+, Ca2+, Mg2+, Co2+, Cd2+, Pb2+, Cu2+, Zn2+ and NH4+) were carried out first in solution and then inside polymeric membrane optodes. Emission light signal was sufficiently brilliant to be captured by a low-cost computer webcam, while a commercial blue-light LED served as monochromic excitation light source. The influence on the ZnPC optode response of the lipophilic sites functionalization was investigated. The visibly (naked eye) observed color change of sensing material from green to red demonstrated the suitability of the ZnPC-based optodes to perform fast monitoring of Cu(II) ions in the concentration range between 6.6 × 10?7 and 2.4 × 10?2 mol/L with a low detection limit (estimated by s/n = 3 method) of 0.3 mg/L, which is lower than WHO guideline value of 2 mg/L.
关键词： chemical optical sensor,novel Zn(II)-porphyrin ligand functionalized with two dibenzo-crown-ether moieties,naked eye detection of Cu(II) ions
更新于2025-09-23 15:21:01
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On the combination of luminescent rare earth MOF and rhodamine dopant with two sensing channels for picric acid
摘要： The present paper reported a hybrid structure for the optical recognition of PA (picric acid). This dye-MOF structure, named as R6h@EuBTC, consisted of a supporting matrix based on rare earth MOF and a sensing probe based on rhodamine dye, which was con?rmed using XRD, IR, thermal and photophysical analysis. R6h@EuBTC's rhodamine absorption in visible region was enhanced by increasing PA concentrations, showing obvious color change and consequently colorimetric sensing. R6h@EuBTC's rhodamine emission component was increased by increasing PA concentrations, while its Eu emission component was slightly quenched by increasing PA concentrations, which offered self-calibrated sensing signals for ratiometric ?uorescent sensing. Linear response and good selectivity were observed for both sensing channels with LOD of 3.9 μM. R6h@EuBTC's sensing mechanism towards PA was the combination of two procedures, which were the emission turn on effect of rhodamine component triggered by PA-released protons and the emission turn off effect of Eu component caused by its electron transfer procedure to PA, respectively. R6h@EuBTC's novelty was its two sensing channels and the practicability of naked eye detection.
关键词： Ratiometric sensing,Optical sensing,Explosive detection,Naked eye detection
更新于2025-09-19 17:15:36
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A novel 1,8-naphthalimide as highly selective naked-eye and ratiometric fluorescent sensor for detection of Hg2+ ions
摘要： A novel colorimetric and ratiometric fluorescent chemosensor, 2-(2-mercaptophenyl)-1H-benzo[de]isoquinoline-1,3-(2H)-dione (L3) is reported for Hg2+ ions. The selective binding of Hg2+ to L3 afforded new absorbance and fluorescence peaks at 438 nm and 480 nm, in addition to the existing bands of L3 at 332 nm and 376 nm. It also showed apparent colour change from colourless to yellowish green and weak fluorescent to bright yellowish green strong fluorescent due to selective binding of Hg2+ ion. The sensor forms a 1:1 stoichiometry with high binding constants (3.89 × 10^4 mol^-1 L) and limit of detection 1.74 × 10^-8 M with high selectivity and sensitivity towards Hg2+ in the presence of other interfering metal ions. More importantly, it has good practicability in environmental water sample. The outcome of photo-physical experiment has also been in good accordance with the time-resolved fluorescence life decays and the density functional theory (DFT) estimations. Moreover, the L3-Hg2+ solution displayed high colorimetric and fluorimetric reversibility via the addition of KI. This reversibility in fluorescence showed potential applicability of chemosensor L3 as 'on–off–on' naked eye sensor.
关键词： Molecular logic gate,Red-shift,DFT,Off–on–off Hg2+ chemosensor,Naked eye detection,Ratiometric fluorescence
更新于2025-09-19 17:15:36
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[IEEE 2019 Photonics North (PN) - Quebec City, QC, Canada (2019.5.21-2019.5.23)] 2019 Photonics North (PN) - Recent Progress in Specialty Optical Fibers for Guiding of OAM and Cylindrical Vector Beams
摘要： Gaze tracking (GT) systems have attracted the attention of researchers as well as the commercial sector. Commercial systems are readily available, but they are usually fabricated at the same size. In this study, we propose a three-dimensional (3-D)-printable frame and an open-source system to fabricate a wearable GT system with low-cost configuration and reasonable performance. A 3-D printer achieves repeatable and adjustable design. The estimated price to make the GT hardware is less than €100, and the system’s average accuracy is 2.58°. Our GT system has a 24-Hz sampling rate, which can analyze human interest points. Another contribution of this study is developing the automatic discrimination of interest objects using our proposed GT and machine learning. The output of this combination system is a database that consists of labeled objects. The label with the highest frequency indicates the object of the highest interest for a corresponding user. Our combination system has a 7-Hz sampling rate and a 3.8% classification error.
关键词： visual programming,Auto-discrimination,three-dimensional (3-D) printer,human-gaze,eye detection
更新于2025-09-19 17:13:59
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - Gaze-Aided Eye Detection via Appearance Learning
摘要： Image based eye detection and gaze estimation have a wide range of potential applications, such as medical treatment, biometrics recognition, human-computer interaction. Though a large number of researchers have attempted to solve the two problems, they still exists some challenges due to the variation in appearance and lack of annotated images. In addition, most related work perform eye detection first, followed by gaze estimation via appearance learning. In this paper, we propose a unified framework to execute the gaze estimation and the eye detection simultaneously by learning the cascade regression models from appearance around the eye related keypoints. Intuitively, there is coupled relationship among location of eye center, shape of eye related keypoints, appearance representation and gaze information. To incorporate these information, at each cascade level, we first learn a model to map the shape and appearance around current eye related keypoints to the three dimension gaze update. Then, with the help of estimated gaze, we further learn a regression model to map the gaze, shape and appearance information to eye location update. By leveraging the power of cascade learning, the proposed method can alternatively optimize the two tasks of eye detection and gaze estimation. The experiments are conducted on benchmarks of GI4E and MPIIGaze. Experimental results show that our proposed method can achieve preferable results in gaze estimation and outperform the state-of-the-art methods in eye detection.
关键词： gaze estimation,eye detection,appearance learning,cascade regression
更新于2025-09-05 23:55:44
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A Remote Free-head Pupillometry Based on Deep Learning and Binocular System
摘要： Objective. Pupillometer plays a key role in a variety of research areas, including disease diagnosis, human-machine interaction, and education. Here we set out to leverage the deep learning theory to develop a remote binocular vision system for pupil diameter estimation. Approach. The system consists of three parts: eye detection, eye tracking, and pupil diameter estimation. We ?rst train a convolutional neural network based on YOLO V2 to perform eye detection, leading to high accuracy and robustness under ambient light interference. By exploring the similarity of binocular camera images, we then propose a master-slave structure for eye tracking, surpassing the traditional parallel structure in tracking speed while keeping considerable accuracy. Furthermore, we develop a pupil diameter estimation algorithm based on binocular vision, avoiding the personal calibration procedure and reducing the measurement distortion error. Main results. Experimental results on real datasets reveal that our system exhibits state-of-the-art performance with high eye detection accuracy (90.6%), fast eye tracking speed (< 11 ms per frame), low pupil diameter estimation error ((0.022 ± 0.017) mm mean absolute error and (0.6 ± 0.7)% percentage of the mean absolute error) and excellent ?exibility. Signi?cance. In contrast with previous pupillometers, which lead to pupil diameter measurement distortion error through a 2D projection image on a single camera, our system measures pupil diameter in 3D space without distortion in?uence, thus improving its robustness to head angle variation and making it more practical for real applications.
关键词： pupil detection,binocular vision,eye tracking,deep learning,eye detection,master-slave structure,Pupil diameter (PD)
更新于2025-09-04 15:30:14