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Heterochiral Doped Supramolecular Coordination Networks for High-Performance Optoelectronics
摘要： Chiral self-sorting has great potential for constructing new complex structures and determining chirality-dependent properties in multicomponent mixtures. However, it is still of great challenge to achieve high fidelity chiral self-discrimination. Besides, the researches on the coordination polymers or metal-organic frameworks (CPs/MOFs) for micro-/nano-optoelectronics are still rare due to their low conductivity and difficulty in developing a rapid and simple scale-up synthetic method. Here, heterochiral supramolecular coordination networks (SCNs) were synthesized by the solvothermal reaction of naphthalene diimide enantiomers and cadmium iodide, using the chirality as a synthetic tuning parameter to control the morphologies. Intriguingly, heterochiral micro-/nanocrystals exhibited photochromic and photodetecting properties. Furthermore, we also developed a simple and efficient doping method to enhance the conductivity and photoresponsivity of micro-/nanocrystals using hydrazine. From experimental and theoretical studies, the mechanism was suggested as follows: the radicals in the singly occupied molecular orbital (SOMO) level of the ligands provide charge carriers that can undergo “through-space” transport between π–π stacked ligands and the electron transfer from adsorbed hydrazine to the SCNs results in reduction of energy gap, leading to increased conductivity. Our findings demonstrate a simple and powerful strategy for implementing coordination networks with redox ligands for micro-/nano-optoelectronic applications.
关键词： chiral self-discrimination,doping,micro-/nano-devices,optoelectronics,supramolecular coordination network
更新于2025-11-19 16:56:35
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Upconversion fluorescent nanoparticles based-sensor array for discrimination of the same variety red grape wines
摘要： In this research, a novel fluorescent sensor array based on upconversion nanomaterials (UCNPs) for the discrimination of the same variety red grape wines from different manufacturers was developed. The sensor array was composed of six elements: one positively charged UCNPs modified with guanidine groups (UCNPs@GDN), two negatively charged UCNPs modified with sulfonic acid groups (UCNPs@SO3H) and phosphonic acid groups (UCNPs@PO(OH)2), respectively, and their mixture 1 (UCNPs@GDN + UCNPs@SO3H), mixture 2 (UCNPs@GDN + UCNPs@PO(OH)2) and mixture 3 {UCNPs@GDN + UCNPs@SO3H + UCNPs@PO(OH)2}. The discrimination mechanism is mainly attributed to the emission of those upconversion fluorescent nanoparticles being quenched by organic ingredients that usually exist in red grape wines. The discrimination of red grape wines was carried out by employing UCNPs@GDN, UCNPs@SO3H and UCNPs@PO(OH)2 in pH = 7.0 HEPES buffer, the mixture 1 and mixture 2 in pH = 9.0 PBS buffer, and mixture 3 in pH = 6.0 Tris–HCl buffer. Principal component analysis (PCA) of the data obtained from our established array showed obvious distinction among the nine red grape wines from different manufacturers. The present work is expected to inspire more marvellous research in the fields of UCNPs and red grape wines identification.
关键词： red grape wines,fluorescence quenching,sensor array,upconversion nanoparticles,discrimination
更新于2025-11-14 15:18:02
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Generalized perspective on chiral measurements without magnetic interactions
摘要： We present a unified description of several methods of chiral discrimination based exclusively on electric-dipole interactions. It includes photoelectron circular dichroism (PECD), enantiosensitive microwave spectroscopy (EMWS), photoexcitation circular dichroism (PXCD), and photoelectron-photoexcitation circular dichroism (PXECD). We show that, in spite of the fact that the physics underlying the appearance of a chiral response is very different in all these methods, the enantiosensitive and dichroic observable in all cases has a unique form. It is a polar vector given by the product of (i) a molecular pseudoscalar and (ii) a field pseudovector specified by the configuration of the electric fields interacting with the isotropic ensemble of chiral molecules. The molecular pseudoscalar is a rotationally invariant property, which is composed from different molecule-specific vectors and in the simplest case is a triple product of such vectors. The key property that enables the chiral response is the noncoplanarity of the vectors forming such triple product. The key property that enables chiral detection without relying on the chirality of the electromagnetic fields is the vectorial nature of the enantiosensitive observable. Our compact and general expression for this observable shows what ultimately determines the efficiency of the chiral signal and if, or when, it can reach 100%. We also discuss the differences between the two phenomena, which rely on the bound states, PXCD and EMWS, and the two phenomena using the continuum states, PECD and PXECD. Finally, we extend these methods to arbitrary polarizations of the electric fields used to induce and probe the chiral response.
关键词： photoelectron-photoexcitation circular dichroism,electric-dipole interactions,field pseudovector,enantiosensitive microwave spectroscopy,photoexcitation circular dichroism,molecular pseudoscalar,chiral discrimination,photoelectron circular dichroism
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Ship Discrimination with Deep Convolutional Neural Networks in Sar Images
摘要： With the advantages of all-time, all-weather, and wide coverage, synthetic aperture radar (SAR) systems are widely used for ship detection to ensure marine surveillance. However, the azimuth ambiguity and buildings exhibit similar scattering mechanisms of ships, which cause false alarms in the detection of ships. To address this problem, self-designed deep convolutional neural networks with the capability to automatically learn discriminative features is applied in this paper. Two datasets, including one dataset reconstructed from IEEEDataPort SARSHIPDATA and the other constructed from 10 scenes of Sentinel-1 SAR images, are used to evaluate our approach. Experimental results reveal that our model achieves more than 95% classification accuracy on both datasets, demonstrating the effectiveness of our approach.
关键词： ship discrimination,Sentinel-1 images,synthetic aperture radar,deep convolutional neural networks
更新于2025-09-23 15:23:52
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Rotated infrared antenna transmitarray for the manipulation of circularly polarized wavefronts
摘要： An IR optical transmitarray is presented based on Antenna Array Sheet (AAS) for the manipulation of circularly polarized light. The unit cell of the transmitarray comprises three layers of metallic elliptical patches. Complete phase control is achieved through the local rotation of each unit cell. Thin refraction and focusing transmitarrays of this sort are demonstrated at infrared frequencies. Moreover, a new concept for realizing a polarization-discriminating device is introduced based on a flat refracting lens. These devices are compatible with current fabrication technology and can become crucial for the integration with other IR and nano-photonic devices.
关键词： Metasurfaces,Transmitarrays,Polarization discrimination,Infrared lens,Circular polarization
更新于2025-09-23 15:23:52
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Label-free fluorescent discrimination and detection of epinephrine and dopamine based on bioinspired in situ copolymers and excitation wavelength switch
摘要： A simple and label-free fluorescence turn-on method is proposed for the discrimination and detection of epinephrine (Ep) and dopamine (DA) via polyethyleneimine (PEI)-initiated in situ copolymerization and excitation wavelength switch. The PEI solution in the presence of Ep, DA and the mixture of Ep and DA are denoted as PEp-PEI, PDA-PEI and MEptDA, respectively. In this study, PEI aqueous solution medium initiates the auto-oxidization of Ep and DA and the bioinspired copolymerization. These resultant copolymers emit yellow-green fluorescence color with a fluorescence emission maximum at 515 nm. Interestingly, these fluorescent copolymers exhibit distinct different excitation spectra, although Ep and DA are structurally very similar. PDA-PEI exhibits only one excitation peak at 385 nm, and PEp-PEI shows dual-excitation mode with two significant excitation peaks at 328 nm and 405 nm, respectively. MEptDA also shows dual-excitation mode with two excitation peaks at 330 nm and 395 nm, respectively. Thus, individual Ep, DA, and their mixture can be discriminated based on the different excitation spectral shapes and peak locations of PEp-PEI, PDA-PEI and MEptDA. Furthermore, the quantitative analysis of Ep and DA in mixture can also be achieved by switching excitation wavelength between 330 and 395 nm and monitoring the fluorescence emission intensity of MEptDA at 515 nm. The fluorescence intensity of MEptDA only related to the concentration of Ep when excited at 330 nm. Moreover, the concentration of DA can also be calculated by subtracting the fluorescence intensity of PEp-PEI from the total fluorescence intensity when excited at 395 nm. The resultant method has been used to simultaneously detect Ep and DA in human urine samples. The proposed fluorescence system is facile, eco-friendly, low-cost, and time-saving, and also provides a new and simple path for discriminating analogues.
关键词： Epinephrine,Fluorescence turn-on,Polyethyleneimine,Dopamine,Simultaneous discrimination and detection
更新于2025-09-23 15:23:52
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Functional Diversity in the Retina Improves the Population Code
摘要： Within a given brain region, individual neurons exhibit a wide variety of different feature selectivities. Here, we investigated the impact of this extensive functional diversity on the population neural code. Our approach was to build optimal decoders to discriminate among stimuli using the spiking output of a real, measured neural population and compare its performance against a matched, homogeneous neural population with the same number of cells and spikes. Analyzing large populations of retinal ganglion cells, we found that the real, heterogeneous population can yield a discrimination error lower than the homogeneous population by several orders of magnitude and consequently can encode much more visual information. This effect increases with population size and with graded degrees of heterogeneity. We complemented these results with an analysis of coding based on the Chernoff distance, as well as derivations of inequalities on coding in certain limits, from which we can conclude that the beneficial effect of heterogeneity occurs over a broad set of conditions. Together, our results indicate that the presence of functional diversity in neural populations can enhance their coding fidelity appreciably. A noteworthy outcome of our study is that this effect can be extremely strong and should be taken into account when investigating design principles for neural circuits.
关键词： retina,neural coding,discrimination error,mutual information,functional diversity,Chernoff distance,population code,heterogeneity
更新于2025-09-23 15:23:52
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Illumination discrimination in the absence of a fixed surface-reflectance layout
摘要： Previous studies have shown that humans can discriminate spectral changes in illumination and that this sensitivity depends both on the chromatic direction of the illumination change and on the ensemble of surfaces in the scene. These studies, however, always used stimulus scenes with a fixed surface-reflectance layout. Here we compared illumination discrimination for scenes in which the surface reflectance layout remains fixed (fixed-surfaces condition) to those in which surface reflectances were shuffled randomly across scenes, but with the mean scene reflectance held approximately constant (shuffled-surfaces condition). Illumination discrimination thresholds in the fixed-surfaces condition were commensurate with previous reports. Thresholds in the shuffled-surfaces condition, however, were considerably elevated. Nonetheless, performance in the shuffled-surfaces condition exceeded that attainable through random guessing. Analysis of eye fixations revealed that in the fixed-surfaces condition, low illumination discrimination thresholds (across observers) were predicted by low overall fixation spread and high consistency of fixation location and fixated surface reflectances across trial intervals. Performance in the shuffled-surfaces condition was not systematically related to any of the eye-fixation characteristics we examined for that condition, but was correlated with performance in the fixed-surfaces condition.
关键词： illumination perception,color vision,eye fixations,chromatic illumination discrimination
更新于2025-09-23 15:22:29
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Experimental test of the relation between coherence and path information
摘要： Quantum coherence stemming from the superposition behaviour of a particle beyond the classical realm, serves as one of the most fundamental features in quantum mechanics. The wave-particle duality phenomenon, which shares the same origin, has a strong relationship with quantum coherence. Recently, an elegant relation between quantum coherence and path information has been theoretically derived. Here, we experimentally test such new duality by l1-norm measure and the minimum-error state discrimination. We prepare three classes of two-photon states encoded in polarisation degree of freedom, with one photon serving as the target and the other photon as the detector. We observe that wave-particle-like complementarity and Bagan’s equality, defined by the duality relation between coherence and path information, is well satisfied. Our results may shed new light on the original nature of wave-particle duality and on the applications of quantum coherence as a fundamental resource in quantum technologies.
关键词： wave-particle duality,minimum-error state discrimination,Bagan's equality,path information,quantum coherence,l1-norm measure
更新于2025-09-23 15:22:29
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Defect detection techniques robust to process variation in semiconductor inspection
摘要： As semiconductor manufacturing process has resulted in downscaling device dimensions, the critical defect size has been becoming smaller and smaller. The highly sensitive optical wafer inspection tool for detecting small defects erroneously detects the process variations as defects and generates a large amount of 'nuisance' information. Thus, the scanning electron microscope (SEM)-based review tool needs to automatically discriminate between defects and nuisance information. To discriminate nuisance information, the absence of defects in the SEM image needs to be accurately detected through an inspection process using the review tool. We propose a defect detection method with (a) an integration of multiple comparison-detection results (IMCD) to suppress the number of defect candidates and (b) a discrimination based on a normal image model (DNPM) to judge whether the candidate is a defect or normal. An evaluation using SEM images of a processed wafer revealed that combining the IMCD and DNPM achieves a nuisance information discrimination rate of 84.4% and a defect detection rate of 93.3%, which are higher than those of the one-class support vector machine (SVM). The proposed methods automatically collect defect images efficiently even when much nuisance information is produced by the optical wafer inspection tool and enable manual visual checks to be reduced.
关键词： image processing,clustering,one-class discrimination,self-organizing map,defect inspection
更新于2025-09-23 15:22:29