Arrangement Of Dots Research Articles

Polariton-assisted incoherent to coherent excitation energy transfer between colloidal nanocrystal quantum dots.

We explore the dynamics of energy transfer between two nanocrystal quantum dots placed within an optical microcavity. By adjusting the coupling strength between the cavity photon mode and the quantum dots, we have the capacity to fine-tune the effective coupling between the donor and acceptor. Introducing a non-adiabatic parameter, γ, governed by the coupling to the cavity mode, we demonstrate the system's capability to shift from the overdamped Förster regime (γ ≪ 1) to an underdamped coherent regime (γ ≫ 1). In the latter regime, characterized by swift energy transfer rates, the dynamics are influenced by decoherence time. To illustrate this, we study the exciton energy transfer dynamics between two closely positioned CdSe/CdS core/shell quantum dots with sizes and separations relevant to experimental conditions. Employing an atomistic approach, we calculate the excitonic level arrangement, exciton-phonon interactions, and transition dipole moments of the quantum dots within the microcavity. These parameters are then utilized to define a model Hamiltonian. Subsequently, we apply a generalized non-Markovian quantum Redfield equation to delineate the dynamics within the polaritonic framework.

Robust Carbon‐Dot Optical Disks for Orthogonal Amplitude‐Polarization Encryption Storage

AbstractHigh‐capacity steganography is crucial for the secure exchange of massive information. Exploring orthogonally optical recording can significantly improve encryption levels. However, due to the lack of robust media, the hidden data are easy to be cracked or destructed. Herein, carbon dots have the switchable memory function between optical transmittance and polarization state after receiving excitation power adjustment is discovered. A large‐area carbon‐based disk is further constructed which is measured to resist the high‐temperature damage at 423 K for more than 405 h and is estimated to remain stable at room‐temperature (301 K) beyond 2341 years. With the alternated arrangement of the dual functional carbon dots at one region of the disk, only by using an amplitude‐type holographic diffraction key can the polarized pattern be correctly read out. The ultra‐high secure encryption strategy also puts a bright way to the applications of 3D image hiding, permanent data preservation, and anti‐counterfeiting labels.

Ultrasonic Punching with Inkjet‐Printed Dot Array for Fabrication of Perforated Metal Pattern as Transparent Heater

This study introduces an aluminum transparent heater manufactured with a perforated pattern by using inkjet printing process. The polymeric sacrificial layer was deposited in a periodic dot arrangement by inkjet printing and a aluminum thin film was deposited using a vacuum deposition process. By the ultrasonic punching to remove inkjet‐printed sacrificial layer, the transparent electrode with perforated metal pattern was formed. From the multiphysics simulation, it is investigated that the narrow region of the perforated pattern is efficient to generate Joule heating. The relationship between electrical and thermal properties is investigated by adjusting the spacing of holes in the aluminum grid. Finally, the performance of the fabricated transparent heater is demonstrated that ice cube placed on top of the manufactured transparent heater is removed within 120 s. This ultrasonic punching with inkjet‐printed sacrificial layer is expected to be applicable to various applications.

Shape from dots: a window into abstraction processes in visual perception

IntroductionA remarkable phenomenon in perception is that the visual system spontaneously organizes sets of discrete elements into abstract shape representations. We studied perceptual performance with dot displays to discover what spatial relationships support shape perception.MethodsIn Experiment 1, we tested conditions that lead dot arrays to be perceived as smooth contours vs. having vertices. We found that the perception of a smooth contour vs. a vertex was influenced by spatial relations between dots beyond the three points that define the angle of the point in question. However, there appeared to be a hard boundary around 90° such that any angle 90° or less was perceived as a vertex regardless of the spatial relations of ancillary dots. We hypothesized that dot arrays whose triplets were perceived as smooth curves would be more readily perceived as a unitary object because they can be encoded more economically. In Experiment 2, we generated dot arrays with and without such “vertex triplets” and compared participants’ phenomenological reports of a unified shape with smooth curves vs. shapes with angular corners. Observers gave higher shape ratings for dot arrays from curvilinear shapes. In Experiment 3, we tested shape encoding using a mental rotation task. Participants judged whether two dot arrays were the same or different at five angular differences. Subjects responded reliably faster for displays without vertex triplets, suggesting economical encoding of smooth displays. We followed this up in Experiment 4 using a visual search task. Shapes with and without vertex triplets were embedded in arrays with 25 distractor dots. Participants were asked to detect which display in a 2IFC paradigm contained a shape against a distractor with random dots. Performance was better when the dots were sampled from a smooth shape than when they were sampled from a shape with vertex triplets.Results and discussionThese results suggest that the visual system processes dot arrangements as coherent shapes automatically using precise smoothness constraints. This ability may be a consequence of processes that extract curvature in defining object shape and is consistent with recent theory and evidence suggesting that 2D contour representations are composed of constant curvature primitives.

The Dot: Statistics, Society, and Graphic Design, c. 1830–1970

Abstract This article takes Chermayeff & Geismar Associates’ cover designs for a paperback reprint series, “Studies in American Negro Life” (1968–c. 1972), as a starting point for investigating the history of the dot as a tool for social-statistical visualization. It first situates the series—which re-issued texts on Black history, sociology, and literature—within the context of 1960s urban unrest in the United States and shows how the arrangements of dots on each cover relate to contemporaneous experiments in urban cartography. It then traces a longer genealogy, considering the dot in relation to the 19th-century emergence of “society” and “the social” as novel epistemic concepts that came to serve as the primary objects of study for the modern social sciences in the 20th century. I address the integral role of statistics in this history, demonstrating how the logic of aggregation that undergirds statistical thinking has been habitually visualized through the dot. The article concludes by returning to the book series, addressing some of the individual covers and arguing that by evoking the visual vocabulary of the social sciences, the cover designs frame the series as a social scientific project overall.

Inkjet-based surface structuring: amplifying sweetness perception through additive manufacturing in foods

Additive manufacturing (AM) is creating new possibilities for innovative tailoring of food properties through multiscale structuring. This research investigated a high-speed inkjet-based technique aimed to modify sweetness perception by creating dot patterns on chocolate surfaces. The dots were formulated from cocoa butter with emulsified water droplets containing the sweetener thaumatin. The number and surface arrangement of dots, which ranged from uniformly distributed patterns to concentrated configurations at the sample’s center and periphery, were varied while maintaining a constant total amount of thaumatin per sample. A sensory panel evaluated sweetness perception at three consumption time points, reporting a significant increase when thaumatin was concentrated on the surface. Specifically, an amplification of sweetness perception by up to 300% was observed, irrespective of dot pattern or consumption time, when compared to samples where thaumatin was uniformly distributed throughout the bulk. However, when thaumatin was concentrated solely at the sample center, maximum sweetness perception decreased by 24%. Conclusively, both the proximity of thaumatin to taste receptors and its spatial distribution, governed by different dot arrangements, significantly influenced taste responsiveness. These findings present a more effective technique to substantially enhance sweetness perception compared to traditional manufacturing techniques. This method concurrently allows for sensorial and visual customization of products. The implications of this study are far-reaching, opening avenues for industrially relevant AM applications, and innovative approaches to study taste formation and perception during oral processing of foods.

True-color light-field display system with large depth-of-field based on joint modulation for size and arrangement of halftone dots.

A true-color light-field display system with a large depth-of-field (DOF) is demonstrated. Reducing crosstalk between viewpoints and increasing viewpoint density are the key points to realize light-field display system with large DOF. The aliasing and crosstalk of light beams in the light control unit (LCU) are reduced by adopting collimated backlight and reversely placing the aspheric cylindrical lens array (ACLA). The one-dimensional (1D) light-field encoding of halftone images increases the number of controllable beams within the LCU and improves viewpoint density. The use of 1D light-field encoding leads to a decrease in the color-depth of the light-field display system. The joint modulation for size and arrangement of halftone dots (JMSAHD) is used to increase color-depth. In the experiment, a three-dimensional (3D) model was constructed using halftone images generated by JMSAHD, and a light-field display system with a viewpoint density of 1.45 (i.e. 1.45 viewpoints per degree of view) and a DOF of 50 cm was achieved at a 100 ° viewing angle.

Cosplay, Academia, and Me—Some Thoughts, and a Note on the Future

Cosplay, Academia, and Me—Some Thoughts, and a Note on the Future

Novel Refreshable Braille Display Based on the Layered Electromagnetic Driving Mechanism of Braille Dots.

In the digital era, Braille displays enable visually impaired people to easily access information. Different from traditional piezoelectric Braille displays, a novel electromagnetic Braille display is realized in this study. The novel display has the advantages of a stable performance, a long service life and a low cost and is based on an innovative layered electromagnetic driving mechanism of Braille dots, which can achieve a dense arrangement of Braille dots and provide a sufficient support force for them. The T-shaped screw compression spring, which causes the Braille dots to fall back instantaneously, is optimized to achieve a high refresh frequency and to enable visually impaired people to read Braille quickly. The experimental results show that under an input voltage of 6 V, the Braille display can work stably and reliably and provide a good fingertip touch; the Braille dot support force is greater than 150 mN, the maximum refresh frequency can reach 50 Hz, and the operating temperature is lower than 32 °C. Therefore, this cost-effective Braille display is expected to benefit a vast number of low-income visually impaired people in developing countries and improve their learning, working and living conditions.

A Green Infrastructure Planning Approach: Improving Territorial Cohesion through Urban-Rural Landscape in Vojvodina, Serbia

Spatial and urban planning are directed towards achieving territorial cohesion as one of the sustainable development goals. Considering the hybrid concept of green infrastructure, this paper aims to provide an “ecological model” of achieving territorial cohesion in spatial and urban planning. Based on the connectivity level analysis between green infrastructure elements (green infrastructure hubs, nodes, gateways and dots), application of the GI concept guides the development of spatial planning scenarios. The application of Voronoi diagrams and landscape graph-based principles contribute to defining the shortest distances between green infrastructure elements, which resulted in the definition of the significance of structural and functional arrangement of green infrastructure dots in the matrix of the urban rural continuum in the territory of the urban-rural landscape of three case studies in Vojvodina, Serbia (Novi Sad, Subotica, Zrenjanin). As a result of this study, green infrastructure dots showed a great potential of application at the local level by developing them through landscape design with creative and artistic elements in order to achieve higher level of cohesion through visual attractivity, multifunctionality and recreation. The level of connectivity between elements of green infrastructure should be considered as an indicator of the sustainable spatial development goals achievement, in the field of nature conservation and territorial and social cohesion.

Improved thermal energy storage with metal foam enhanced phase change materials considering various pore arrangements: A pore-scale parallel lattice Boltzmann solution

Low thermal conductivity of the phase change materials (PCMs) is the main impediment that causes avoiding their extensive usage for thermal energy storage. Metal foams can be used with PCMs to overcome this weakness to reach an enhanced PCM. The main challenge of using metal foam is to reach the optimal geometrical, mechanical, and physical properties to meet the desired performance. This study investigates the effect of pore arrangement in a homogenous closed-cell aluminum metal foam. Afterward, a comparison is presented between various arrangements and pore diameters to examine the effect of pore configuration and diameter on thermal energy storage performance. Three pore arrangements are considered: Simple (simple linear arrangement of pores); Staggered (straticulate/alternative arrangement of pores); and Dots (simple pores with smaller ones diagonally placed between them). To simulate the melting process coupled with conduction and natural convection, the parallel lattice Boltzmann solver (PALABOS) –an open-source library consists of various predefined functions to solve complex thermo-fluidic problems– with enthalpy-based method is developed, and the results are validated. Different numerical simulations have been done to conduct the parameter study. In general, the Dots arrangement is relatively more effective than the two other studied arrangements. For dp = 5 mm, the melting times of PCM for all cases are similar to one another. However, for dp = 10 mm, the Dots arrangement could reduce the melting time by 20% compared to Staggered and Simple arrangements.

The complexity of simple counting: ERP findings reveal early perceptual and late numerical processes in different arrangements

The counting process can only be fully understood when taking into account the visual characteristics of the sets counted. Comparing behavioral data as well as event-related brain potentials (ERPs) evoked by different task-irrelevant arrangements of dots during an exact enumeration task, we aimed to investigate the effect of illusory contour detection on the counting process while other grouping cues like proximity were controlled and dot sparsity did not provide a cue to the numerosity of sets. Adult participants (N = 37) enumerated dots (8–12) in irregular and two different types of regular arrangements which differed in the shape of their illusory dot lattices. Enumeration speed was affected by both arrangement and magnitude. The type of arrangement influenced an early ERP negativity peaking at about 270 ms after stimulus onset, whereas numerosity only affected later ERP components (> 300 ms). We also observed that without perceptual cues, magnitude was constructed at a later stage of cognitive processing. We suggest that chunking is a prerequisite for more fluent counting which influences automatic processing (< 300 ms) during enumeration. We conclude that the procedure of exact enumeration depends on the interaction of several perceptual and numerical processes that are influenced by magnitude and arrangement.

Flexible and reusable parylene C mask technology for applications in cascade impactor air quality monitoring systems

The development of traceable new methodologies to quantify elemental air pollutants in particulate matter (PM) supports modernization of methods used in air quality monitoring networks in Europe. In the framework of the EURAMET EMPIR AEROMET II project, the combination of cascade impactor aerosol sampling and total reflection X-ray fluorescence elemental spectroscopy (TXRF) was investigated. This technique requires a traceable calibration based on reference samples. This paper describes a new, simple and effective method to produce such reference samples using flexible, reusable, and low-cost parylene C shadow masks, fabricated by photolithographic steps. These shadow masks can be used to produce reference samples that mimic the Dekati cascade impactor's deposition patterns by applying as-prepared micro stencils to 30 mm acrylic substrates and evaporating a reference material (Ti) in arrangements of thin circular dots. The highly flexible direct patterning of acrylic discs with reference material, otherwise impossible with conventional photolithography, allows multiple reusing of the same micro stencils. The aspect ratios of the dots could be repeated with an error less than 4%. A first set of standard reference samples for the 13 stages of the Dekati cascade impactor was produced and preliminary TXRF measurements of the deposited Ti masses were performed. The centricity of the deposition patterns turned out to be an important parameter for the quality of the TXRF results. The parylene mask technology for the production of reference samples turns out to be a promising new approach for the traceable calibration of TXRF spectrometers for the quantification of element concentrations in environmental aerosol samples but, due to its great versatility, it could be used for several other micropatterning applications on conventional and unconventional substrates. • Reference samples with cascade impactor patterns were successfully realized by using a shadow mask technology. • Highly flexible direct patterning of acrylic substrates was performed. • Parylene C microstencils were easily fabricated by using photolithographic steps and they were successfully reused multiple times. • Good accuracy achieved on features down to 250 μm with an error in diameter less than 4%. • Centricity and orientation of designed patterns on substrates influence the TXRF signal.

Rationally Designed Topological Quantum Dots in Bottom-Up Graphene Nanoribbons.

Bottom-up graphene nanoribbons (GNRs) have recently been shown to host nontrivial topological phases. Here, we report the fabrication and characterization of deterministic GNR quantum dots whose orbital character is defined by zero-mode states arising from nontrivial topological interfaces. Topological control was achieved through the synthesis and on-surface assembly of three distinct molecular precursors designed to exhibit structurally derived topological electronic states. Using a combination of low-temperature scanning tunneling microscopy and spectroscopy, we have characterized two GNR topological quantum dot arrangements synthesized under ultrahigh vacuum conditions. Our results are supported by density-functional theory and tight-binding calculations, revealing that the magnitude and sign of orbital hopping between topological zero-mode states can be tuned based on the bonding geometry of the interconnecting region. These results demonstrate the utility of topological zero modes as components for designer quantum dots and advanced electronic devices.

Impact of electron-phonon coupling on electron transport through T-shaped arrangements of quantum dots in the Kondo regime.

We calculate the conductance through strongly correlated T-shaped molecular or quantum dot systems under the influence of phonons. The system is modelled by the extended Anderson–Holstein Hamiltonian. The finite-U mean-field slave boson approach is used to study many-body effects. Phonons influence both interference and correlations. Depending on the dot unperturbed energy and the strength of electron–phonon interaction, the system is occupied by a different number of electrons that effectively interact with each other repulsively or attractively. This leads, together with the interference effects, to different spin or charge Fano–Kondo effects.

Localization in the Crowd with Topological Constraints

We address the problem of crowd localization, i.e., the prediction of dots corresponding to people in a crowded scene. Due to various challenges, a localization method is prone to spatial semantic errors, i.e., predicting multiple dots within a same person or collapsing multiple dots in a cluttered region. We propose a topological approach targeting these semantic errors. We introduce a topological constraint that teaches the model to reason about the spatial arrangement of dots. To enforce this constraint, we define a persistence loss based on the theory of persistent homology. The loss compares the topographic landscape of the likelihood map and the topology of the ground truth. Topological reasoning improves the quality of the localization algorithm especially near cluttered regions. On multiple public benchmarks, our method outperforms previous localization methods. Additionally, we demonstrate the potential of our method in improving the performance in the crowd counting task.

Elucidation of the Mechanism of Quantum Dot Arrangement Based on Self-Assembly of an Azobenzene Derivative

Abstract The formation of well-defined nanostructures comprising assembled semiconductor quantum dots (QDs) is a challenging research task. Recently, we found that the introduction of π-conjugated molecules with a self-assembly ability into small CdSe QDs led to the formation of highly ordered QD arrangements. Here, we demonstrate the in-depth coaggregation process of large-sized CdSe QDs and azobenzene derivative 1 possessing an amino group functioning as an adhesive to the QD surface. Upon mixing the above QDs with assembled azobenzene derivative 1 in apolar solvents, linearly arranged QD structures along assembled azobenzene derivative 1 were formed over time. In the formed coaggregates, efficient energy transfer between the arranged QDs occurred, as confirmed by a change in the emission spectra and lifetimes. Analysis of time-dependent emission properties revealed the coaggregation mechanism of QDs and 1.

Proximity model of perceived numerosity.

The occupancy model (OM) was proposed to explain how the spatial arrangement of dots in sparse random patterns affects their perceived numerosity. The model's central thesis maintained that each dot seemingly fills or occupies its surrounding area within a fixed radius ro and the total area collectively occupied by all the dots determines their apparent number. Because the perceptual system is not adapted for the precise estimation of area, it looks likely that the OM is just a convenient computational algorithm that does not necessarily correspond to the processes that actually take place in the perceptual system. As an alternative, the proximity model (PM) was proposed, which instead relies on a binomial function with the probability β characterizing the perceptual salience with which each element can be registered by the perceptual system. It was also assumed that the magnitude of β is proportional to the distance between a dot and its nearest neighbor. A simulation experiment demonstrated that the occupancy area computed according to the OM can almost perfectly be replicated by the mean nearest neighbor distance. It was concluded that proximity between elements is a critical factor in determining their perceived numerosity, but the exact algorithm that is used for the measure of proximities is yet to be established.

Single photon sources with near unity collection efficiencies by deterministic placement of quantum dots in nanoantennas

Deterministic coupling between photonic nodes in a quantum network is an essential step toward implementing various quantum technologies. The omnidirectionality of free-standing emitters, however, makes this coupling highly inefficient, in particular if the distant nodes are coupled via low numerical aperture (NA) channels such as optical fibers. This limitation requires placing quantum emitters in nanoantennas that can direct the photons into the channels with very high efficiency. Moreover, to be able to scale such technologies to a large number of channels, the placing of the emitters should be deterministic. In this work, we present a method for directly locating single free-standing quantum emitters with high spatial accuracy at the center of highly directional bullseye metal–dielectric nanoantennas. We further employ non-blinking, high quantum yield colloidal quantum dots for on-demand single-photon emission that is uncompromised by instabilities or non-radiative exciton recombination processes. Taken together, this approach results in a record-high collection efficiency of 85% of the single photons into a low NA of 0.5, setting the stage for efficient coupling between on-chip, room temperature nanoantenna-emitter devices and a fiber or a remote free-space node without the need for additional optics.

A Highly Ordered Quantum Dot Supramolecular Assembly Exhibiting Photoinduced Emission Enhancement

AbstractMulticomponent supramolecular assembly systems enable the generation of materials with outstanding properties, not obtained from single‐component systems, via a synergetic effect. Herein, we demonstrate a novel supramolecular coassembly system rendering highly ordered quantum dot (QD) arrangement structures formed via the self‐assembly of azobenzene derivatives, where the photocontrollable photoluminescence (PL) properties of the QDs are realized based on photoisomerization. Upon mixing the assembled azobenzene derivatives and QDs in apolar media, a time‐evolution coaggregation into hierarchical nanosheets with a highly ordered QD arrangement structure occurs. Upon photoirradiation, the nanosheets transform into ill‐defined aggregates without arranged QDs together with enhancing the PL intensity. In days, the photoirradiated coaggregates undergo recovery of the PL properties corresponding to the arranged QDs through thermal isomerization.