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Super-resolution Mapping of Enhanced Emission by Collective Plasmonic Resonances
摘要： Plasmonic particle arrays have remarkable optical properties originating from their collective behavior, which results in resonances with narrow line widths and enhanced electric fields extending far into the surrounding medium. Such resonances can be exploited for applications in strong light?matter coupling, sensing, lasing, and light harvesting, nonlinear nanophotonics, solid-state lighting. However, as the lattice constants associated with plasmonic particle arrays are on the order of their resonance wavelengths, mapping the interaction between point dipoles and plasmonic particle arrays cannot be done with diffraction-limited methods. Here, we map the enhanced emission of single fluorescent molecules coupled to a plasmonic particle array with ～20 nm in-plane resolution by using stochastic super-resolution microscopy. We find that extended lattice resonances have minimal influence on the spontaneous decay rate of an emitter but instead can be exploited to enhance the outcoupling and directivity of the emission. Our results can guide the rational design of future optical devices based on plasmonic particle arrays.
关键词： light?matter interaction,nanophotonics,single molecule localization,collective resonances,plasmonics,super-resolution microscopy
更新于2025-11-25 10:30:42
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How to unravel the chemical structure and component localization of individual drug-loaded polymeric nanoparticles by using tapping AFM-IR
摘要： AFM-IR is a photothermal technique that combines AFM and infrared (IR) spectroscopy to unambiguously identify the chemical composition of a sample with tens of nanometer spatial resolution. So far, it has been successfully used in contact mode in a variety of applications. However, the contact mode is unsuitable for soft or loosely adhesive samples such as polymeric nanoparticles (NPs) of less than 200 nm of wide interest for biomedical applications. We describe here the theoretical basis of the innovative tapping AFM-IR mode that can address novel challenges in imaging and chemical mapping. The new method enables gaining information not only on NP morphology and composition, but also reveals drug location and core–shell structures. Whereas up to now the locations of NP components could only be hypothesized, tapping AFM-IR allows accurately visualizing both the location of the NPs’ shells and that of the incorporated drug, pipemidic acid. The preferential accumulation of the drug in the NPs’ top layers was proved, despite its low concentration (<1 wt%). These studies pave the way towards the use of tapping AFM-IR as a powerful tool to control the quality of NP formulations based on individual NP detection and component quantification.
关键词： tapping mode,chemical mapping,core–shell structure,drug localization,polymeric nanoparticles,AFM-IR
更新于2025-11-14 15:18:02
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Sensor Localization for Highly-Deformed Partially Calibrated Arrays with Moving Targets
摘要： In this letter, a sensor localization technique for highly-deformed partially calibrated arrays with multiple moving targets is proposed. The deformed array is divided into several subarrays. The first subarray is composed of the pre-calibrated sensors, while the sensors in the other subarrays are uncalibrated. The positions of the sensors are estimated from the phase differences between the pre-calibrated sensors and the uncalibrated sensors. The phase ambiguities caused by the highly-deformed sensor positions can be solved using the subspace orthogonality and the movement of multiple targets. Simulation results evaluate the performance of the proposed method, and the Cramer–Rao bounds are compared.
关键词： highly-deformed sensor array,partially calibrated sensor array,phase ambiguity,Sensor localization
更新于2025-09-23 15:23:52
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Entanglement generation between distant parties via disordered spin chains
摘要： We study the emergence of bipartite entanglement between a pair of spins weakly connected to the ends of a linear disordered X Y spin-1/2 channel. We analyze how their concurrence responds to structural and on-site fluctuations embodied by long-range spatially-correlated sequences. We show that the end-to-end entanglement is very robust against disorder and asymmetries in the channel provided that the degree of correlations are strong enough and both entangling parties are tuned accordingly. Our results offer further alternatives in the design of stable quantum communication protocols via imperfect spin channels.
关键词： Quantum entanglement,Quantum state transfer,Anderson localization
更新于2025-09-23 15:23:52
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Broadband Emission in Hybrid Organic–Inorganic Halides of Group 12 Metals
摘要： We report syntheses, crystal and electronic structures, and characterization of three new hybrid organic?inorganic halides (R)ZnBr3(DMSO), (R)2CdBr4·DMSO, and (R)CdI3(DMSO) (where (R) = C6(CH3)5CH2N(CH3)3, and DMSO = dimethyl sulfoxide). The compounds can be conveniently prepared as single crystals and bulk polycrystalline powders using a DMSO?methanol solvent system. On the basis of the single-crystal X-ray diffraction results carried out at room temperature and 100 K, all compounds have zero-dimensional (0D) crystal structures featuring alternating layers of bulky organic cations and molecular inorganic anions based on a tetrahedral coordination around group 12 metal cations. The presence of discrete molecular building blocks in the 0D structures results in localized charges and tunable room-temperature light emission, including white light for (R)ZnBr3(DMSO), bluish-white light for (R)2CdBr4·DMSO, and green for (R)CdI3(DMSO). The highest photoluminescence quantum yield (PLQY) value of 3.07% was measured for (R)ZnBr3(DMSO), which emits cold white light based on the calculated correlated color temperature (CCT) of 11,044 K. All compounds exhibit fast photoluminescence lifetimes on the timescale of tens of nanoseconds, consistent with the fast luminescence decay observed in π-conjugated organic molecules. Temperature dependence photoluminescence study showed the appearance of additional peaks around 550 nm, resulting from the organic salt emission. Density functional theory calculations show that the incorporation of both the low-gap aromatic molecule R and the relatively electropositive Zn and Cd metals can lead to exciton localization at the aromatic molecular cations, which act as luminescence centers.
关键词： zero-dimensional structures,broadband emission,group 12 metals,exciton localization,photoluminescence quantum yield,hybrid organic?inorganic halides
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - Cleveland, OH, USA (2018.10.17-2018.10.19)] 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - A Capsule Endoscope System for Wide Visualization Field and Location Tracking
摘要： A capsule endoscope system that can support wide visualization field and location tracking capability is proposed. The body channel communication (BCC) transceiver integrated circuit (IC) and 4-camera module is integrated in the proposed capsule endoscope. To support 4-camera image transmission, BCC transceiver provide high speed data rate with low-power. With cross-coupled camera module, 360-degree of image capturing is supported. For the accurate (sub-cm range) capsule localization, contact attenuation compensation scheme is proposed. The system is integrated on the rigid flexible printed circuit board (PCB) to reduce system form factor. The proposed endoscope system operates longer than 8 hours with 4fps and 12 hours with 2fps with conventional small size coin battery and verified through human mimicking phantom.
关键词： High data rate,Low-power,Capsule endoscope,Body channel communication (BCC),Localization,Location tracking,Transmitter,Wireless
更新于2025-09-23 15:23:52
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[IEEE 2018 Ubiquitous Positioning, Indoor Navigation and Location-Based Services (UPINLBS) - Wuhan (2018.3.22-2018.3.23)] 2018 Ubiquitous Positioning, Indoor Navigation and Location-Based Services (UPINLBS) - Image Processing Based Indoor Localization System for Assisting Visually Impaired People
摘要： Indoor localization or indoor positioning system is a known as a process of detecting position of any object or people inside a building or room by different sensory data collected from different devices using different techniques such as radio waves, magnetic fields, acoustic signals or other procedures. However, lacking of a standard localization system is still a very big concern. Solution of this issue can be very beneficial for people in many cases but it can be especially very beneficial for the visually impaired people. In this paper, an image processing based indoor localization system has been developed using OpenCV and Python by following color detection technique to detect position of the user with maximum accuracy and then location of user is determined by analyzing that location matrix. Location accuracy depends on the size of the matrix and successful identification of target color. Firebase real time database was added to the system which made real time operations between server and the user end device easier. To justify the proposed model, successful experiments were conducted in indoor environments as well and correct result was achieved each time by detecting accurate locations. This will be very advantageous to observe the fully or partially sightless people and guide them towards their destination and also to inspect them for their security purpose.
关键词： Color Segmentation,Indoor localization,Image Processing,Indoor positioning system,Wireless communication,Connected object detection
更新于2025-09-23 15:23:52
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Unconventional charge and spin-dependent transport properties of a graphene nanoribbon with line-disorder
摘要： Electronic transport with a line (or a few lines) of Anderson-type disorder in a zigzag graphene nanoribbon is investigated in the presence of Rashba spin-orbit interaction. Such line-disorders give rise to a peculiar behavior in both charge as well as spin-polarized transmission in the following sense. In the weak-disorder regime, the charge transport data show Anderson localization up to a certain disorder strength, beyond which the extended states emerge and start dominating over the localized states. These results are the hallmark signature of a selectively disordered (as opposed to bulk disorder) graphene nanoribbon. However, the spin-polarized transport shows a completely contradicting behavior. Further, the structural symmetries are shown to have an important role in the spintronic properties of the nanoribbons. Moreover, the edge-disorder scenario (disorder selectively placed at the edges) seems to hold promise for the spin-filter and switching device applications.
关键词： Anderson localization,spin transport,graphene nanoribbon,line-disorder,Rashba spin-orbit interaction
更新于2025-09-23 15:23:52
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Ethyl violet–bovine serum albumin fluorescent protein nanovessels target to lysosomes and mitochondria
摘要： Aim: Organelles are essential in maintaining homeostasis of mammalian cells. Monitoring the morphology and dynamics of organelles is of significance in cell state determination and disease diagnosis. Materials & methods: We describe here a new material called ethyl violet–bovine serum albumin fluorescent protein nanovessel (EV–BSA FPN). Upon heating, BSA was denatured to form higher polyhedral structures, which was prone to EV binding. These dye–protein hybrid materials were red fluorescence emissive upon excitation. Results: EV–BSA FPNs can be readily internalized by mammalian cells and dual localized in lysosomes and mitochondria. Besides, EV–BSA FPN can serve as carriers and efficiently deliver drug into cells. Conclusion: EV–BSA FPNs can be dual function fluorescent vessels for both dual-organelle imaging and drug delivery.
关键词： dual-organelle localization,fluorescent protein nanovessel,lysosomes and mitochondria imaging,ethyl violet,drug carrier
更新于2025-09-23 15:23:52
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ObstacleWatch
摘要： Walking while using a smartphone is becoming a major pedestrian safety concern as people may unknowingly bump into various obstacles that could lead to severe injuries. In this paper, we propose ObstacleWatch, an acoustic-based obstacle collision detection system to improve the safety of pedestrians who are engaged in smartphone usage while walking. ObstacleWatch leverages the advanced audio hardware of the smartphone to sense the surrounding obstacles and infers fine-grained information about the frontal obstacle for collision detection. In particular, our system emits well-designed inaudible beep signals from the smartphone built-in speaker and listens to the reflections with the stereo recording of the smartphone. By analyzing the reflected signals received at two microphones, ObstacleWatch is able to extract fine-grained information of the frontal obstacle including the distance, angle and size for detecting the possible collisions and to alert users. Our experimental evaluation under two real-world environments with different types of phones and obstacles shows that ObstacleWatch achieves over 92% accuracy in predicting obstacle collisions with distance estimation errors at about 2 cm. Results also show that ObstacleWatch is robust to different sizes of objects and is compatible to different phone models with low energy consumption.
关键词： Smartphone,Acoustic Ranging,Mobile Sensing,Pedestrian Safety,Acoustic Localization
更新于2025-09-23 15:23:52