科研趋势
历年科研结果应用趋势一目了然
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Road Information Extraction from High-Resolution Remote Sensing Images Based on Road Reconstruction
摘要： Traditional road extraction algorithms, which focus on improving the accuracy of road surfaces, cannot overcome the interference of shelter caused by vegetation, buildings, and shadows. In this paper, we extract the roads via road centerline extraction, road width extraction, broken centerline connection, and road reconstruction. We use a multiscale segmentation algorithm to segment the images, and feature extraction to get the initial road. The fast marching method (FMM) algorithm is employed to obtain the boundary distance field and the source distance field, and the branch backing-tracking method is used to acquire the initial centerline. Road width of each initial centerline is calculated by combining the boundary distance fields, before a tensor field is applied for connecting the broken centerline to gain the final centerline. The final centerline is matched with its road width when the final road is reconstructed. Three experimental results show that the proposed method improves the accuracy of the centerline and solves the problem of broken centerline, and that the method reconstructing the roads is excellent for maintain their integrity.
关键词： road reconstruction,fast marching method,road extraction,centerline extraction,tensor voting更新于2025-09-23 15:23:52
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Subtle structure tailoring of metal-free triazine luminogens for highly efficient ultralong organic phosphorescence
摘要： Highly efficient ultralong organic phosphorescence (UOP) based on a series of metal-free triazine luminogens was achieved via subtly structural tailoring of bromine substituted positions. Impressively, p-BrAT in solid state displayed high phosphorescence efficiency up to 9.7% with a long lifetime of 386 ms, which was one of the highest efficient UOP materials reported so far in metal-free compounds.
关键词： Isomerism,Ultralong organic phosphorescence (UOP),Crystal engineering,H-Aggregation,Intermolecular interactions更新于2025-09-23 15:23:52
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Photocatalytic degradation of phenol by LaFeO3 nanocrystalline synthesized by gel combustion method via citric acid route
摘要： Focusing on the photocatalytic degradation of phenol under visible light, the synthesized lanthanum orthoferrites (LaFeO3) by gel combustion method using citric acid as sacrificial agent were investigated. With the highest reaction temperature of 200 °C, the physicochemical properties of synthesized samples were characterized by X-Ray diffraction (XRD) analysis, Brunauer–Emmet–Teller (BET), and Energy Dispersive X-Ray spectroscopy (EDS). On the other hand, UV–Vis spectroscopy analysis was carried out to determine the phenol photodegradation activities and mechanism. The results suggested the well-defined LaFeO3 nanocrystals with specific area of 28 m2 g?1 were successfully synthesized. Besides that, variations in operating parameters such as pH, catalyst dosage and initial concentration of phenol in synthetic wastewater were also examined. In conclusion, LaFeO3 nanocrystalline exhibited an exceptional photocatalytic activity for phenol degradation, thus providing a perfect alternative for pharmaceutical wastewater treatment.
关键词： Citric acid,Photocatalytic activity,Lanthanum orthoferrite,Phenol,Gel combustion更新于2025-09-23 15:23:52
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Performance Assessment of High Resolution Airborne Full Waveform LiDAR for Shallow River Bathymetry
摘要： We evaluate the performance of full waveform LiDAR decomposition algorithms with a high-resolution single band airborne LiDAR bathymetry system in shallow rivers. A continuous wavelet transformation (CWT) is proposed and applied in two fluvial environments, and the results are compared to existing echo retrieval methods. LiDAR water depths are also compared to independent field measurements. In both clear and turbid water, the CWT algorithm outperforms the other methods if only green LiDAR observations are available. However, both the definition of the water surface, and the turbidity of the water significantly influence the performance of the LiDAR bathymetry observations. The results suggest that there is no single best full waveform processing algorithm for all bathymetric situations. Overall, the optimal processing strategies resulted in a determination of water depths with a 6 cm mean at 14 cm standard deviation for clear water, and a 16 cm mean and 27 cm standard deviation in more turbid water.
关键词： bathymetry,full waveform,wavelet transformation,LiDAR更新于2025-09-23 15:23:52
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One-pot three-component synthesis and photophysical properties of highly fluorescent novel 4-alkyl-3-aryl-2,6-dicyanoanilines by using tris(hydroxymethyl)aminomethane as a catalyst
摘要： Novel 4-alkyl-3-aryl-2,6-dicyanoanilines were synthesized by a multi-component one-step reaction of aromatic aldehyde, malononitrile and aliphatic aldehyde using tris(hydroxymethyl)aminomethane (THAM) as a catalyst under microwave (MW) irradiation or conventional heating. The optimized reaction condition involved use of 2.5 equivalents of THAM under MW irradiation at 140 W using 20 % MW power for 5 min or conventional heating at 80 °C for 8 h in dimethylformamide. The photophysical properties including λmax, quantum yield and Stokes’ shifts of newly synthesized molecules were studied. All compounds exhibited quantum yield in the range of 0.04 to 0.52 with respect to standard quinine sulphate having quantum yield 0.54. The Stokes’ shifts of all compounds were found in the range of 41-105 nm. The current strategy provides operationally simple protocol using THAM as a catalyst to synthesize 4-alkyl-3-aryl-2,6-dicyanoanilines with diverse structural features to make them available for exploration of their photophysical as well as biological applications.
关键词： Fluorescent,Quantum Yield,Tris(hydroxymethyl)aminomethane,Microwave,Malononitrile,Dicyanoanilnes更新于2025-09-23 15:23:52
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Study on the enhancement of photocatalytic environment purification through ubiquitous-red-clay loading
摘要： Tungsten oxide (WO3) is regarded as a promising visible-light-sensitive photocatalyst, but its activity is not high. Further enhancement of its activity has been anticipated using techniques such as loading of a cocatalyst to apply the oxide to indoor environmental remediation; Pt has been reported as a good cocatalyst for WO3 photocatalysis. However, Pt is precious and expensive metal. Thus, in this study, we sought to find a ubiquitous cocatalyst and suitable photocatalyst system. As a result, this study revealed that loading a ubiquitous material of red-clay enhanced WO3 photocatalytic activity remarkably. As photocatalyst samples, mixtures consisting of the clay and WO3 with different weight ratios were prepared using a simple kneading method. Their photocatalytic activity was evaluated from decomposition of harmful organic contaminant, 2-propanol into CO2 under visible-light irradiation. The WO3 with 10% of the clay loading showed the highest activity among the samples and much higher activity than pure WO3. This higher activity might derive from the clay’s promotion of H2O2 decomposition and charge separation (holes and electrons). The H2O2 was generated from photocatalytic O2 reduction. This formation and accumulation on the pure WO3 surface led to decreased activity.
关键词： TiO2,Zeolite,Natural mineral,Optical absorption,Remediation更新于2025-09-23 15:23:52
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Advancing the PROSPECT-5 Model to Simulate the Spectral Reflectance of Copper-Stressed Leaves
摘要： This paper proposes a modified model based on the PROSPECT-5 model to simulate the spectral reflectance of copper-stressed leaves. Compared with PROSPECT-5, the modified model adds the copper content of leaves as one of input variables, and the specific absorption coefficient related to copper (Kcu) was estimated and fixed in the modified model. The specific absorption coefficients of other biochemical components (chlorophyll, carotenoid, water, dry matter) were the same as those in PROSPECT-5. Firstly, based on PROSPECT-5, we estimated the leaf structure parameters (N), using biochemical contents (chlorophyll, carotenoid, water, and dry matter) and the spectra of all the copper-stressed leaves (samples). Secondly, the specific absorption coefficient related to copper (Kcu) was estimated by fitting the simulated spectra to the measured spectra using 22 samples. Thirdly, other samples were used to verify the effectiveness of the modified model. The spectra with the new model are closer to the measured spectra when compared to that with PROSPECT-5. Moreover, for all the datasets used for validation and calibration, the root mean square errors (RMSEs) from the new model are less than that from PROSPECT-5. The differences between simulated reflectance and measured reflectance at key wavelengths with the new model are nearer to zero than those with the PROSPECT-5 model. This study demonstrated that the modified model could get more accurate spectral reflectance from copper-stressed leaves when compared with PROSPECT-5, and would provide theoretical support for monitoring the vegetation stressed by copper using remote sensing.
关键词： vegetation remote sensing,leaf,PROSPECT,reflectance model,copper,spectra更新于2025-09-23 15:23:52
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Construction of a Biosensor Based on a Combination of Cytochrome c, Graphene, and Gold Nanoparticles
摘要： A biosensor based on a combination of cytochrome c (Cyt c), electrochemical reduced graphene oxides (ERGO), and gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) was fabricated. The proposed biosensor electrode was denoted as GCE/ERGO-Na?on/AuNPs/Cyt c/Na?on, where ERGO-Na?on was deposited by dropping graphene oxides-Na?on mixed droplet ?rst and following electrochemical reduction, AuNPs were directly deposited on the surface of the ERGO-Na?on modi?ed electrode by electrochemical reduction, and other components were deposited by the dropping-dry method. The effect of the deposition amount of AuNPs on direct electrochemistry of Cyt c in the proposed electrode was investigated. The hydrogen peroxide was taken to evaluate the performance of the proposed biosensor. The results showed that the biosensor has great analytical performance, including a high sensitivity, a wide linear range, a low detection limit, and good stability, reproducibility, and reliability.
关键词： gold nanoparticles,cytochrome c,graphene,direct electrochemistry,biosensor,hydrogen peroxide更新于2025-09-23 15:23:52
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Degradation of tetracycline by medium pressure UV-activated peroxymonosulfate process: Influencing factors, degradation pathways, and toxicity evaluation
摘要： This study employed the medium pressure UV/peroxymonosulfate (MPUV/PMS), a new sulfate radical-based advanced oxidation process, to eliminate tetracycline (TTC) in water. At pH = 3.7, initial TTC concentration of 11.25 μM, PMS dosage of 0.2 mM and UV dose of 250 mJ cm-2, 82 % of TTC was degraded by MPUV/PMS. The second-order reaction rate constants of TTC with SO4?- and ?OH were found to be 1.4 × 1010 M-1 s-1 and 6.0 × 109 M-1 s-1, respectively. Radical quenching experiments indicated that ?OH played the major role in the degradation of TTC. Higher PMS dosage (0.1 mM~1.0 mM) and higher pH (3~11) could accelerate the TTC removal. Besides, the presence of Cl- (0.1 mM~5.0 mM) and CO32- (0.05 mM~0.5 mM) could also promote the reaction. Eight transformation products (TPs) were identified, and the potential degradation pathways mainly involved hydroxylation, demethylation and decarbonylation processes. The variation in the genotoxicity was investigated using the umu-test, and the results indicate that the genotoxicity of TTC after the MPUV/PMS treatment significantly increased during the initial stage. In addition, the ecotoxicity and mutagenicity of TTC and its TPs were predicted using quantitative structure-activity relationship (QSAR) analysis, and the results revealed that some TPs could have equivalent and even higher toxicity than TTC. MPUV/PMS showed better performance in TTC degradation in real waters than in Milli-Q water. MPUV/PMS is concluded to be an efficient method for removing TTC, but more attention should be paid to the changes of toxicity during this process.
关键词： Tetracycline,Toxicity,Hydroxyl radical,Sulfate radical,Transformation products更新于2025-09-23 15:23:52
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Reference Module in Chemistry, Molecular Sciences and Chemical Engineering || Sensors Overview
摘要： Sensor research has always been a very dynamic area. We have advanced significantly since the primary form of sensor, litmus paper, was first made for crude pH measurements. Since the mid-1980s, there has been an explosion of research interests in sensor development as witnessed by the overwhelming amount of papers published during this period. Sensor research has always been driven by commercial needs. It is also an area that crosses over several developing areas, and has benefited by the advances in material sciences, engineering, and affordable computer technology. Consequently, in recent years, there is huge diversity of sensors available in the marketplace that covers industrial, environmental, and clinical applications. Yet, despite the large amounts of capital and human resources invested in the development of new devices, the best sensor commercially available is probably still the pH glass electrode in terms of its selectivity, sensitivity, dynamic range, response time, robustness, and ease of manufacture. The big successes in commercial terms since the late 1950s have been, in the chemical sector, the oxygen electrode based on the Clark cell, the fluoride electrode and ion-selective electrodes (ISEs) used in clinical analyzers, and the solid-state oxygen sensors based on zirconium oxide (ZrO2) and titanium oxide (TiO2) used in automobile air-to-fuel control; whereas more recently in the biosensor sector, the various glucose sensors based on glucose oxidase and the pregnancy test strips have been successful. There are clear advantages in using sensors in field (or in vitro) applications compared to conventional analytical instruments and therefore the search for better performing and cheaper sensors will always interest the researchers in both the industrial and academic worlds. This article deals mainly with chemical and biochemical transduction mechanisms to provide analytical information, while dealing in brief with materials and other recent developments.
更新于2025-09-23 15:23:52