- 标题
- 摘要
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- 实验方案
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Metal-Ion Displacement Approach for Optical Recognition of Thorium: Application of a Molybdenum(VI) Complex for Nanomolar Determination and Enrichment of Th(IV)
摘要： An azine-based molybdenum (Mo(VI)) complex (M1) is exploited for selective detection of thorium (Th(IV)) ions through a metal-ion displacement protocol. Th(IV) displaces Mo(VI) from M1 instantly leading to the formation of the Th(IV) complex, having orange-red emission. Consequently, a red shift of the emission wavelength along with 41-fold ?uorescence enhancement is observed. This unique method allows detection of Th(IV) as low as 1.5 × 10?9 M. The displacement of Mo(VI) from M1 by Th(IV) is established by spectroscopic studies and kinetically followed by the stopped-?ow technique. The displacement binding constant for Th(IV) is notably strong, 4.59 × 106 M?1. Extraction of Th(IV) from aqueous solution to the ethyl acetate medium using M1 has been achieved. The silica-immobilized M1 e?ciently enriches Th(IV) from its reservoir through solid-phase extraction. Computational studies (density functional theory) support experimental ?ndings.
关键词： Solid-phase extraction,Molybdenum(VI) complex,Fluorescence enhancement,Thorium detection,Metal-ion displacement
更新于2025-09-23 15:21:01
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Optimized feature extraction for radiomics analysis of <sup>18</sup> F-FDG-PET imaging
摘要： Radiomics analysis of 18F-FDG-PET/CT images promises for an improved in-vivo disease characterization. To date, several studies reported significant variations in textural features due to differences in patient preparation, imaging protocols, lesion delineation and feature extraction. Our objective was to study variations of features prior to a radiomics analysis of 18F-FDG-PET data and to identify those feature extraction and imaging protocol parameters that minimize radiomic feature variations across PET imaging systems. Methods. A whole-body National Electrical Manufacturers Association image quality phantom was imaged with 13 PET/CT systems at 12 different sites following local protocols. We selected 37 radiomic features related to the four largest spheres (17-37 mm) in the phantom. Based on a combined analysis of voxel size, bin size and lesion volume changes, feature and imaging system ranks were established. A 1-way analysis of variance (ANOVA) was performed over voxel size, bin size and lesion volume subgroups to identify the dependency and the trend change of feature variations across these parameters. Results. Feature ranking revealed that the gray-level co-occurrence matrix (GLCM) and shape features are the least sensitive to PET imaging system variations. Imaging system ranking illustrated that the use of point-spread function (PSF), small voxel sizes and narrow Gaussian post-filtering helped minimize feature variations. ANOVA subgroup analysis indicated that variations of each of the 37 features and for a given voxel size and bin size parameter can be minimized. Conclusions. Our study provides guidance to selecting optimized features from 18F-FDG-PET/CT studies. We were able to demonstrate that feature variations can be minimized for selected image parameters and imaging systems. These results can help imaging specialists and feature engineers in increasing the quality of future radiomic studies involving PET/CT.
关键词： radiomics,18F-FDG PET/CT,feature extraction
更新于2025-09-23 15:21:01
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[IEEE 2018 37th Chinese Control Conference (CCC) - Wuhan (2018.7.25-2018.7.27)] 2018 37th Chinese Control Conference (CCC) - Background Filtering and Vehicle Detection with Roadside Lidar Based on Point Association
摘要： The high-resolution traffic data (HRTD) is important to intelligent transportation systems (ITS). The roadside LiDAR (light detection and ranging) sensors can provide HRTD by collecting real-time 3D point clouds of surrounding objects. To analyze HRTD, background filtering and vehicle detection are the essential steps. This paper presents an algorithm to extract background and detect vehicles based on point association in 3D point clouds. To improve the accuracy, DBSCAN is combined with time-limited window for vehicle detection according to the relationship between vehicle points.
关键词： vehicle detection,background extraction,Roadside LiDAR,point association
更新于2025-09-23 15:21:01
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Identification of Citrus Trees from Unmanned Aerial Vehicle Imagery Using Convolutional Neural Networks
摘要： Remote sensing is important to precision agriculture and the spatial resolution provided by Unmanned Aerial Vehicles (UAVs) is revolutionizing precision agriculture workflows for measurement crop condition and yields over the growing season, for identifying and monitoring weeds and other applications. Monitoring of individual trees for growth, fruit production and pest and disease occurrence remains a high research priority and the delineation of each tree using automated means as an alternative to manual delineation would be useful for long-term farm management. In this paper, we detected citrus and other crop trees from UAV images using a simple convolutional neural network (CNN) algorithm, followed by a classification refinement using superpixels derived from a Simple Linear Iterative Clustering (SLIC) algorithm. The workflow performed well in a relatively complex agricultural environment (multiple targets, multiple size trees and ages, etc.) achieving high accuracy (overall accuracy = 96.24%, Precision (positive predictive value) = 94.59%, Recall (sensitivity) = 97.94%). To our knowledge, this is the first time a CNN has been used with UAV multi-spectral imagery to focus on citrus trees. More of these individual cases are needed to develop standard automated workflows to help agricultural managers better incorporate large volumes of high resolution UAV imagery into agricultural management operations.
关键词： UAS,tree identification,citrus,precision agriculture,CNN,feature extraction,deep learning,superpixels
更新于2025-09-23 15:21:01
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Rapid screening of rhodamine B in food by hydrogel solid-phase extraction coupled with direct fluorescence detection
摘要： Rhodamine B (RhB), which is vividly colored, although illegal and potentially carcinogenic, has been reported widely as present in various foods, including chili powder, preserved plums, sausage and sweets, presenting a significant health risk. In this work, solid-phase extraction (SPE), coupled with direct fluorescence detection on the same extraction medium, is proposed for rapid onsite screening for RhB in food without sample pretreatment. Parameters that affected extraction of RhB were explored. The lowest amount of RhB, detected on glass, was 2 ng and the lowest detectable concentration in food samples was 0.5 mg/kg, as verified by HPLC. The analysis time was less than 5 min, including sampling. In addition, the recovery rate of this method was found to be triple of that from the cotton gauze reported in literature. The proposed method has promise as a rapid, onsite screening protocol for food safety.
关键词： Solid-phase extraction,Fluorescence,Food safety screening,PVA hydrogel,Rhodamine B
更新于2025-09-23 15:19:57
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Equivalent Circuit Parameters of Hybrid Quantum-Dot Solar Cells
摘要： We experimentally investigate the equivalent circuit parameters of hybrid quantum-dot (QD) solar cells consisted of InAs/GaAs and GaSb/GaAs QDs. The hybrid QD solar cell samples are fabricated by stacking one pair and three pairs of InAs/GaAs and GaSb/GaAs QD layers. Four equivalent circuit models are applied to fit the experimentally obtained current-voltage characteristics of the investigated samples. The relevant circuit parameters are photocurrent, reverse saturation current, diode ideality factor, series resistance, and shunt resistance. The best fitted model of all samples contains both series and shunt resistances. According to the fitting result, the diode ideality factor of 2, which indicates the dominant recombination current, is always obtained. Comparing the extracted parameters from two single-pair hybrid QD solar cells, the effects of structural stacking sequence can be discussed in term of light absorption and carrier storage properties. We have found that an increase of stacking number from one pair to three pairs deteriorates the solar cell performance. This might be caused by an excessive total QD layer thickness or a presence of dislocation defects in that sample.
关键词： Parameter Extraction,Current-Voltage Characteristics,Solar Cell,Quantum Dot
更新于2025-09-23 15:19:57
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Development of low laser energy levels in small-incision lenticule extraction
摘要： Purpose: To evaluate the outcomes of 4 low laser energy levels after small-incision lenticule extraction (SMILE) surgery. Setting: Zhongshan Ophthalmic Center, Guangzhou, China. Design: Prospective randomized clinical trial. Methods: This study evaluated consecutive patients who had SMILE to correct myopia or myopia with astigmatism. Eyes were placed into groups based on the laser energy used during surgery (ie, 105 nJ, 110 nJ, 115 nJ, or 120 nJ). All patients had a thorough ophthalmic examination preoperative and at 4 timepoints over 3 months postoperatively. Black areas and surface regularity of the extracted lenticules were observed and evaluated qualitatively and quantitatively. Results: The study comprised 124 eyes of 62 patients (40 women, 22 men), with 31 eyes in each laser energy group. The incidence of black areas was 45.16% (14 of 31 eyes), 12.90% (4 of 31 eyes), 16.13% (5 of 31 eyes), and 12.90% (4 of 31 eyes) for 105 nJ, 110 nJ, 115 nJ, and 120 nJ, respectively. The mean time for lenticule creation was the longest in the 105 nJ group (P = .015). The greatest increase in corneal thickness postoperatively occurred with 105 nJ (P < .05). Regression was highest in the 105 nJ group at 3 months (P < .01). However, corneal horizontal coma (C8) was lowest in the 105 nJ group at 1 week (P = .032). The lenticular surface in the 110 nJ group was the smoothest (P = .011). All contrast sensitivity values varied with time and recovered to preoperative levels by 1 week or 1 month. In all eyes, the uncorrected distance visual acuity and corrected distance visual acuity were good, with no statistically significant differences between the 4 energy groups. Conclusions: The 105 nJ group, in which the lowest energy was used, had the highest risk for black areas, serious postoperative corneal edema, and a significant healing response.
关键词： small-incision lenticule extraction,laser energy levels,black areas,SMILE,corneal edema
更新于2025-09-23 15:19:57
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Implementation of deep convolutional neural network for classification of multiscaled and multiangled remote sensing scene
摘要： With the evolution of convolutional neural networks, extraction of deep features for accurate classification of Remote Sensed (RS) images have gained lot of momentum. However, due to variation in the scale of high resolution remote sensed images, accurate classification still remains a challenging task. Moreover, along with the scale, variation in the angle also decreases the accuracy of extraction of deep features using convolutional neural network. In this paper, a Multiscale and Multiangle convolutional neural network (MSMA-CNN) is proposed which extracts deep features of the RS images by employing several convolutional, pooling and fully connected layers which are discriminant, nonlinear and invariant. In MSMA-CNN, along with the spatial features, spectral features are also considered for classification of remote sensing scenes thus, making the entire system robust. The RS images are scaled at different levels using Gaussian Pyramid Decomposition and rotated at different angles and further features are derived using maximally stable extremal regions (MSER) at spectral and spatial level which are further concatenated and fed to the MSMA-CNN. A regularization parameter is added to get the results for test images as close as the trained images. A hybrid MSMA-CNN structure is designed by altering various parameters of the CNN structure to get improved optimized performance. To demonstrate the effectiveness of the proposed method, we compared the results on six challenging high-resolution remote sensing datasets and achieve a classification accuracy of 92.25% which shows significant improvement compared to the other state-of-the-art scene classification methods in terms classifcational accuracy and computational cost.
关键词： Deep feature extraction,classification of remote sensed images,multiscale and multiangle remote sensed images,convolutional neural networks
更新于2025-09-23 15:19:57
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[IEEE 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Berlin, Germany (2019.6.23-2019.6.27)] 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - In-Situ Transmission Electron Microscopy Coupled with Resonant Microcantilever for Comprehensive Evaluating Sulfurization Performance of Zinc Oxide Nanowires
摘要： This paper reports a new technique with in-situ transmission electron microscopy (in-situ TEM) and resonant microcantilever to comprehensively evaluate sulfurization performance of ZnO nanowires. Herein, in-situ TEM is used to real-time observe the sulfurization process of ZnO nanowires under SO2-contained atmosphere. temperature-varying micro-gravimetric method, thermodynamic interaction between ZnO nanowires and SO2 molecules is quantitatively evaluated by resonant microcantilever. By exposing the ZnO nanowires sample to SO2-contained atmosphere, a thick shell layer of ZnSO3 can be formed onto the surface of ZnO nanowires and a novel core-shell nanowire structure of ZnO@ZnSO3 is obtained finally. According to our comprehensive evaluation results, the ZnO nanowires sample with 100 nm diameter exhibits high reactive to SO2 molecules and is suitable for SO2 capture and storage.
关键词： sulfurization process,ZnO nanowires,thermodynamic parameter extraction,In-situ TEM
更新于2025-09-23 15:19:57
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Naphthalene imide dimer as interface engineering material: An efficient strategy for achieving high-performance perovskite solar cells
摘要： How to design and synthesize interfacial engineered materials that have efficient surface passivation and electron extraction properties is an important problem in the field of optoelectronic materials. Herein, a simple naphthalene imide dimer, namely 2FBT2NDI, is developed by Stille coupling reaction with a high yield, and it is used as interface engineering for inverted perovskite solar cells (PSC). Owing to the existence of intermolecular interactions between MAPbI3 and the 2FBT2NDI layer, the introduction of the interfacial layer can passivate the surface defects of perovskite film and improve interface contact. In addition, 2FBT2NDI exhibits suitable energy levels and high electron mobility because of its large linear conjugated skeleton containing two fluorine atoms, which are beneficial for electron extraction for efficient PSCs. Employing 2FBT2NDI as an interfacial layer, inverted PSCs show a maximum power conversion efficiency of 20.1%, which is over 14% higher than that of the control devices without interfacial layer (17.1%). These results highlight that the naphthalene imide dimer can potentially be used as a commercializable interfacial material for achieving high-performance PSCs.
关键词： electron extraction,perovskite solar cell,naphthalene imide,surface passivation,interface engineering
更新于2025-09-23 15:19:57