Physical Size Research Articles

Supercavity Modes Excited by Bessel‐Type Plasmon Polaritons

AbstractHigh‐index dielectric resonators are favorable to enhance light‐matter interaction with the advantages of low loss and multipolar resonances. However, realizing a high‐Q factor in a single dielectric cavity remains a challenge especially in lossy systems such as that in plasmonics. Here, the resonant modes of a dielectric cylinder excited is explored by bessel‐type plasmon polaritons and reveal the general dependence of its eigenfrequency on the physical size. Based on this fundamental a universal and robust approach is proposed to find the high‐Q supercavity modes, which arise in the vicinity of the resonance crossing features of two coupled resonant modes in the same radiation channel. Following the proposed principle, one cannot only construct a series of high‐Q modes, but also predict their corresponding size parameters and resonant frequencies without relying on the heavy computations of parameter scanning. Such high‐Q mode can be easily extended from visible wavelengths to other frequency regime due to scale invariance of the eigenfrequency and the insensitivity of the Q‐factor to the permittivity (real part) of the plasmonic substrate. The findings provide guideline for the engineering of high‐Q modes and may open up a pathway to design resonant meta‐optics devices in lossy dielectric‐metal composite system.

Ionic Solvent-Assisted MAPbBr3 Perovskite Film for Two-Photon Pumped Single-Mode Laser.

Miniaturized coherent light sources on the nanoscale are highly desired for on-chip photonics integration. However, when approaching the diffraction limit, the sub-wavelength-scale all-dielectric lasers are difficult to realize due to the trade-off between lasing performance and physical size. Especially for a thin-film laser, usually an externally complex cavity is required to provide the necessary optical feedback. Herein, we successfully shrink the MAPbBr3 perovskite thin-film laser to sub-wavelength scale (300 nm) with simplified cavity design using only an ultraviolet glue layer and a quartz glass. The morphology quality and the gain properties of the film are enhanced by introducing ionic liquid. Consequently, the stable and low-threshold single-mode laser with a highly linear polarization degree of 78.6% and a narrow line width of 0.35 nm is achieved under two-photon excitation. The excellent single-mode laser with sub-wavelength scale and ultrasimplified structure could provide a facile and versatile platform for future integrated optoelectronic devices.

A dual-band dual-polarized low-side-lobe transmitarray using independent amplitude and phase controllable elements

In this paper, a novel transmitarray (TA) element with independent control capability of amplitude and phase under dual-band dual-polarized operation is proposed. By changing the physical size of the TA element, the phase variation of the element can cover 360° at two bands. Moreover, the phase change of the frequency band is less than 30° when the phase of the other band is changed. Meanwhile, a higher maximal transmission amplitude can be maintained when varying the phase. Amplitude modulation is achieved by rotating the TA element. Utilizing the proposed TA element, a dual-band dual-linear polarization (LP) TA with low side lobe level (SLL) operating at 12.5 GHz and 14.25 GHz is designed. The SLL can be decreased by amplitude modulation of the elements. The measured peak gains of the proposed TA are 25.96 dBi and 25.89 dBi at 12.5 GHz and 14.25 GHz. In addition, the measured SLLs of the yoz/xoz planes are −22.4 dB/−22.4 dB and −22.5dB/−22.3 dB at 12.5 GHz and 14.25 GHz, respectively. The proposed TA shows good SLL performances and great application potential in satellite communication systems.

The visual perception of wetness: Multisensory integration of visual and tactile stimuli.

A multitude of sensory modalities are involved in humans' experience of wetness, yet we know little of the integratory role of vision. Therefore, the aim was to quantify the effect of physical stain volume, chroma and size on wetness perception, and to compare wetness perception under different sensory conditions, including visuotactile and visual only interactions. Eighteen participants visually observed and/or used their index fingerpad to dynamically interact with stimuli varying in physical wetness (0, 2.16 × 10-4 or 3.45 × 10-4 ml mm-2), stain chroma (clear, light, dark) and stain size (1150 or 5000 mm2). After interaction participants rated wetness perception using a visual analogue scale (very dry to very wet). In visual only conditions participants were able to differentiate between dry and wet stimuli, and could also discriminate between different magnitudes of wetness with the addition of tactile cues. In both visual only and visuotactile conditions greater stain chroma resulted in increased wetness perception. Stain size did not have a significant effect in either condition. These results show that visual cues influence wetness perception (R2 = 0.29), but indicate that visual dominance does not apply in these sensory integrations. Findings are relevant for the design of products with wetness management properties.

Planetesimal Accretion at Short Orbital Periods

Abstract Formation models in which terrestrial bodies grow via the pairwise accretion of planetesimals have been reasonably successful at reproducing the general properties of the Solar System, including small-body populations. However, planetesimal accretion has not yet been fully explored in the context of the wide variety of recently discovered extrasolar planetary systems, in particular those that host short-period terrestrial planets. In this work, we use direct N-body simulations to explore and understand the growth of planetary embryos from planetesimals in disks extending down to ≃1 day orbital periods. We show that planetesimal accretion becomes nearly 100% efficient at short orbital periods, leading to embryo masses that are much larger than the classical isolation mass. For rocky bodies, the physical size of the object begins to occupy a significant fraction of its Hill sphere toward the inner edge of the disk. In this regime, most close encounters result in collisions, rather than scattering, and the system does not develop a bimodal population of dynamically hot planetesimals and dynamically cold oligarchs, as is seen in previous studies. The highly efficient accretion seen at short orbital periods implies that systems of tightly packed inner planets should be almost completely devoid of any residual small bodies. We demonstrate the robustness of our results to assumptions about the initial disk model, and we also investigate the effects that our simplified collision model has on the emergence of this non-oligarchic growth mode in a planet-forming disk.

How Large Is a Disk—What Do Protoplanetary Disk Gas Sizes Really Mean?

It remains unclear what mechanism is driving the evolution of protoplanetary disks. Direct detection of the main candidates, either turbulence driven by magnetorotational instabilities or magnetohydrodynamical disk winds, has proven difficult, leaving the time evolution of the disk size as one of the most promising observables able to differentiate between these two mechanisms. But to do so successfully, we need to understand what the observed gas disk size actually traces. We studied the relation between R CO,90%, the radius that encloses 90% of the 12CO flux, and R c , the radius that encodes the physical disk size, in order to provide simple prescriptions for conversions between these two sizes. For an extensive grid of thermochemical models, we calculate R CO,90% from synthetic observations and relate properties measured at this radius, such as the gas column density, to bulk disk properties, such as R c and the disk mass M disk. We found an empirical correlation between the gas column density at R CO,90% and disk mass: . Using this correlation we derive an analytical prescription of R CO,90% that only depends on R c and M disk. We derive R c for disks in Lupus, Upper Sco, Taurus, and the DSHARP sample, finding that disks in the older Upper Sco region are significantly smaller (〈R c 〉 = 4.8 au) than disks in the younger Lupus and Taurus regions (〈R c 〉 = 19.8 and 20.9 au, respectively). This temporal decrease in R c goes against predictions of both viscous and wind-driven evolution, but could be a sign of significant external photoevaporation truncating disks in Upper Sco.

Miniaturized frequency‐selective surface with reduced number of metallic vias for electromagnetic shielding

SummaryA miniaturized frequency‐selective surface (FSS) for radio frequency (RF) filtering applications is reported in this paper. The proposed FSS is designed to operate with band stop property at 1.57 GHz. The FSS element is developed using highly convoluted lines running on either side of the substrate interconnected using via lines. This specific arrangement increases the electrical length of the resonator without increasing the physical size. Furthermore, the stability towards polarization variation and independence to different angles of incidence are other major concerns in the design of FSS. The FSS unit cell has rotational symmetry thereby providing polarization‐independent operation. The angular independence is tested for various incidence angles, and the results are presented. The performance of the FSS is validated in real time, and the results are presented. The maximum realized transmission loss is 27 dB at 1.57 GHz, and the attenuation bandwidth with reference 10 dB shielding level is estimated to be 400 MHz centered around 1.57 GHz. The convolution technique along with shorting vias has offered this extreme miniaturization ranging from 7% to 95.7% with reference to most of the FSS reported for L‐band services such as radio, telecommunications, military, and aircraft surveillance.

Underwater Acoustically Guided Docking Method Based on Multi-Stage Planning

Autonomous underwater vehicles (AUVs) are important in areas such as underwater scientific research and underwater resource collection. However, AUVs suffer from data portability and energy portability problems due to their physical size limitation. In this work, an acoustic guidance method for underwater docking is proposed to solve the problem of persistent underwater operation. A funnel docking station and an autonomous remotely operated vehicle (ARV) are used as the platform for designing the guidance algorithms. First, the underwater docking guidance is divided into three stages: a long-range approach stage, a mid-range adjustment stage and a short-range docking stage. Second, the relevant guidance strategy is designed for each stage to improve the docking performance. Third, a correction method based on an ultra-short baseline (USBL) system is proposed for the ARV’s estimate of the depth, relative position and orientation angle of the docking station. To verify the feasibility of the docking guidance method, in this work, tests were performed on a lake and in a shallow sea. The success rate of autonomous navigation docking on the lake was 4 out of 7. The success rate of acoustic guidance docking on the lake and in the shallow sea were 11 out of 14 and 6 out of 8, respectively. The experimental results show the effectiveness of the docking guidance method in lakes and shallow seas.

Super-compact equal/unequal half-mode substrate integrated waveguide filtering power dividers using complementary G-shaped resonator

ABSTRACT In this paper, three super-compact equal/unequal filtering power dividers (FPDs) by combining the half-mode substrate integrated waveguide (HMSIW) platform and the metamaterial unit cell are proposed. To miniaturized the total dimension of the proposed equal/unequal FPDs, the evanescent mode technique, the half-mode technique, and the stepped-impedance resonator (SIR) technique have been utilized, simultaneously. In the modified metamaterial unit cell, which is called the complementary G-shaped resonator (CGR) unit cell, the quasi stepped-impedance slot line is replaced instead of the conventional slot line in the circular complementary split-ring resonator (CSRR) unit cell. Accordingly, the electrical size of the modified CGR unit cell is smaller than the conventional circular CSRR unit cell with the same physical sizes. Employing the introduced CGR unit cell and HMSIW structure, three equal/unequal FPDs with arbitrary power-dividing ratios have been designed and simulated. To illustration the performance of the proposed components, three HMSIW FPDs with different power division ratios of 1:1, 1:4, and 1:8 have been fabricated and measured. A reasonable agreement between simulated and measured results has been achieved. The results demonstrate that a miniaturization factor of about 0.64 is achieved.

Programmatic mapping and estimating the population size of female sex workers, men who have sex with men, people who inject drugs and transgender populations in Kenya.

Effective coverage of Human Immunodeficiency Virus prevention services for Key Populations (KPs) including female sex workers (FSWs), men who have sex with men (MSM), people who inject drugs (PWID) and transgender (TG) people necessitates periodic validation of physical venues and size estimates. Kenya conducted a robust size estimation of KPs in 2012 and a repeat mapping and size estimation exercise was conducted in 2018 to update KP Size Estimates and sub-typologies within each County for calculation of realistic program indicators. A prospective mixed methods programmatic mapping approach adopted comprised two steps. The first step involved consolidating and documenting all known venues where KPs congregate while the second step included visiting and validating these venues confirming their active status. Data were collected in 34 out of 47 Counties in Kenya between January and March 2018. Data collected included estimated number of KPs (range), venue typology and timing of operation of each venue. We estimated a total number of 167,940 (129,271 to 206,609) FSWs; 32,580 (24,704 to 40,455) MSM; 16,063 (12,426 to 19,691) PWIDs and 4,305 (2,826 to 5,783) transgender people congregating at 10,250, 1,729, 401 and 1,218 venues respectively. Majority of the venues for FSW (81%), MSM (64%) and transgender people (67%) were bars with and without lodging, PWIDs were mostly found on streets and injecting dens (70%). Around 9% of FSW and MSM and11% of PWIDs were below the age of 18 years. This study provided information on young KPs, female PWIDs, MSWs and for the first time, TG people in Kenya. The exercise updated size estimates of KPs by typology and provided new evidence for resource allocation, planning of interventions and targets. Programmatic mapping continues to be a useful approach supporting programs to achieve high levels of coverage and prioritize resources.

Technological process optimization and measurement of image quality of the electrically bifocal metalens.

This Letter describes the design procedure and process optimization of the electrically bifocal metalens. In our design, horizontal and vertical polarization is manipulated by applying a suitable voltage to a twisted nematic liquid crystal (TN-LC) cell. Each nanostructure is designed to be a rectangular prism, making different polarizations of light experience various phase delays, thus causing bi-focus. We selected lithographical methods to fabricate our metalens because of the minimum physical size, which can be as small as 50 nm, and the maximum aspect ratio, which is as high as 15. Furthermore, to increase the tolerance and make the sidewall vertical and smooth, we coated different characteristics of photoresist sensitivity to the upper and lower layers. After the development, the mushroom-type photoresist makes Ni easier to strip while in the lift-off process, thus increasing the quality of the whole metalens. Our experiment shows that the focal lengths and focusing efficiencies corresponding to the two polarizations are similar to the simulation results. The proposed electrically modulated bifocal metalens can be utilized in different applications and combined with other optical components.

High-speed TIRF and 2D super-resolution structured illumination microscopy with a large field of view based on fiber optic components.

Super-resolved structured illumination microscopy (SR-SIM) is among the most flexible, fast, and least perturbing fluorescence microscopy techniques capable of surpassing the optical diffraction limit. Current custom-built instruments are easily able to deliver two-fold resolution enhancement at video-rate frame rates, but the cost of the instruments is still relatively high, and the physical size of the instruments based on the implementation of their optics is still rather large. Here, we present our latest results towards realizing a new generation of compact, cost-efficient, and high-speed SR-SIM instruments. Tight integration of the fiber-based structured illumination microscope capable of multi-color 2D- and TIRF-SIM imaging, allows us to demonstrate SR-SIM with a field of view of up to 150 × 150 µm2 and imaging rates of up to 44 Hz while maintaining highest spatiotemporal resolution of less than 100 nm. We discuss the overall integration of optics, electronics, and software that allowed us to achieve this, and then present the fiberSIM imaging capabilities by visualizing the intracellular structure of rat liver sinusoidal endothelial cells, in particular by resolving the structure of their trans-cellular nanopores called fenestrations.

Advanced Skeletal Ossification Is Associated with Genetic Variants in Chronologically Young Beef Heifers.

Osteogenesis is a developmental process critical for structural support and the establishment of a dynamic reservoir for calcium and phosphorus. Changes in livestock breeding over the past 100 years have resulted in earlier bone development and increased physical size of cattle. Advanced skeletal maturity is now commonly observed at harvest, with heifers displaying more mature bone than is expected at 30 months of age (MOA). We surmise that selection for growth traits and earlier reproductive maturity resulted in co-selection for accelerated skeletal ossification. This study examines the relationship of single nucleotide polymorphisms (SNPs) in 793 beef heifers under 30 MOA with USDA-graded skeletal maturity phenotypes (A-, B-, C- skeletal maturity). Further, the estrogen content of FDA-approved hormonal implants provided to heifers prior to harvest was evaluated in association with the identified SNPs and maturities. Association tests were performed, and the impact of the implants were evaluated as covariates against genotypes using a logistic regression model. SNPs from the ESR1, ALPL, PPARGC1B, SORCS1 genes, and SNPs near KLF14, ANKRD61, USP42, H1C1, OVCA2, microRNA mir-29a were determined to be associated with the advanced skeletal ossification phenotype in heifers. Higher dosage estrogen implants increased skeletal maturity in heifers with certain SNP genotypes.

Social and environmental factors affecting the amount of property taxes collected by local authorities in Israel

The payable amount of municipal property tax in Israel, locally known as Arnona, is based on the property's physical size, functional use, and several locational attributes, but not on the property's value, as more common elsewhere. This unusual taxation system originated in the late 1960's, when the State of Israel abolished the 1934 British mandatory ad valorem taxation system in order to establish a more stable tax base for local authorities during the period of highly volatile property prices. As the Arnona tax system is not commonly used elsewhere and its studies are infrequent, little is known about its advantages and disadvantages. In particular, the question remains whether the amount of taxes, collected by this system, actually reflects market realities and societal justice, while encouraging local authorities to protect the environment. The present study aims to answer this question, by analyzing the most recent fiscal data on local authorities in Israel, published in 2017. As the study reveals, there appears to be no significant correlation between the amount of Arnona taxes collected, on the one hand, and the market values of properties and environmental conditions in the local authorities, on the other, while the link between the amount of Arnona taxes and socio-economic status of local residents appears to be weak. As an efficient system of property taxation should be equitable, reflect market realities, and help to protect the environment, our conclusion is that the taxation system in question does not meet these requirements and should ultimately be modified or replaced by a more efficient taxation approach. The study’s results might be informative for policy-makers in countries and regions, in which traditional ad valorem taxation system might be difficult to implement due to a limited number of comparable properties transactions, or due to rapidly changing market values of properties, thus leading to a need of choosing an appropriate taxation alternative.

Spatial correlation and pore morphology analysis of limestone calcined clay cement (LC3) via machine learning and image-based characterisation

Comprehending the microstructure of LC3 is of paramount importance since it governs majority properties of cement. Here, we investigate the spatial correlation and pore morphology of LC3, revealing microstructural refinement effects through deep learning and image-based characterisation. A deep learning model was developed to characterise the spatial correlation of the local features of 28-day LC3 with optimised resolution and physical image size, identifying a lower probability of connected pores occurring but a higher likelihood of connected solid particles in LC3 than in OPC. A 33% lower maximum correlation revealed by two-point correlation analysis inferred that LC3 possessed a smaller RVE size and increased packing density. The pore morphological analysis based on BSE images indicated a higher hydration rate and pore deformation in LC3. These findings demonstrate the microstructural refinement mechanisms of LC3 but also lay the foundation for localised microstructural characterisation of cementitious materials with the potential to complement existing traditional analyses.

Microemulsions of Nonionic Surfactant with Water and Various Homologous Esters: Preparation, Phase Transitions, Physical Property Measurements, and Application for Extraction of Tricyclic Antidepressant Drugs from Aqueous Media.

Microemulsions are nanocolloidal systems composed of water, an oil, and a surfactant, sometimes with an additional co-surfactant, which have found a wide range of practical applications, including the extractive removal of contaminants from polluted water. In this study, microemulsion systems, including a nonionic surfactant (Brij 30), water, and esters selected from two homologous series of C1-C6 alkyl acetates and ethyl C1-C4 carboxylates, respectively, were prepared by the surfactant titration method. Phase transitions leading to the formation of Winsor II and Winsor IV microemulsions were observed and phase diagrams were constructed. The dependences of phase transitions on the salinity and pH and the addition of isopropanol as a co-surfactant were also investigated. Some physical properties, namely density, refractive index, electrical conductivity, dynamic viscosity, and particle size, were measured for a selection of Winsor IV microemulsions, providing further insight into some other phase transitions occurring in the monophasic domains of phase diagrams. Finally, Winsor II microemulsions were tested as extraction solvents for the removal of four tricyclic antidepressant drugs from aqueous media. Propyl acetate/Brij 30/H2O microemulsions provided the best extraction yields (>90%), the highest Nernst distribution coefficients (~40-88), and a large volumetric ratio of almost 3 between the recovered purified water and the resulting microemulsion extract. Increasing the ionic strength (salinity) or the pH of the aqueous antidepressant solutions led to an improvement in extraction efficiencies, approaching 100%. These results could be extrapolated to other classes of pharmaceutical contaminants and suggest ester- and nonionic surfactant-based microemulsions are a promising tool for environmental remediation.

A dual-solver CFD model for conjugate heat transfer in continuous thermal processing

High temperature heat treatment of powders is a common operation in the manufacturing of a range of commercial products. Often, powders are heated or cooled in discrete quantities while being conveyed through a continuous furnace or oven, where a certain temperature–time profile is required for product quality reasons. For powders that are contained and conveyed in oven-ware (saggars), heat-transfer occurs between the surrounding gas phase and the powder material and oven-ware, as well as between oven ware that is vertically stacked.The large physical size and long transit times through typical industrial furnaces (up to 40 m length) means that a full transient CFD solution for both gas and solid phases is computationally very expensive . In this study, a novel CFD simulation model is developed for conjugate heat transfer in the cooling section at the outlet of a continuous furnace. A particular novel feature in this model is the inclusion of heat conduction in multiple solid domains. A dual-solver approach enables the convective and radiant heat-transfer processes in the gas phase are modelled using a steady-state conjugate solver, while the heat conduction processes within the powders and saggars are modelled using a time-dependent conjugate solver that solves for heat conduction only. Using only steady-state solution for the gas phase enables a “snap-shot” of the thermal performance of the system to be generated in a reasonable time frame, which has practical implications for modelling of large-scale industrial equipment. In the “dual-solver” approach, heat fluxes at solid boundaries from the steady-state model are applied as boundary conditions to the transient solver, while the temperature field resulting from the solution of the transient solver is then applied to the steady-state model. Radiative cooling effects are accounted for using a discrete-ordinates model.

The Feasibility of Using a Deep Learning-Based Model to Determine Cardiac Computed Tomographic Contrast Dose.

This study aimed to predict contrast effects in cardiac computed tomography (CT) from CT localizer radiographs using a deep learning (DL) model and to compare the prediction performance of the DL model with that of conventional models based on patients' physical size. This retrospective study included 473 (256 men and 217 women) cardiac CT scans between May 2014 and August 2017. We developed and evaluated DL models that predict milligrams of iodine per enhancement of the aorta from CT localizer radiographs. To assess the model performance, we calculated and compared Pearson correlation coefficient ( r ) between the actual iodine dose that was necessary to obtain a contrast effect of 1 HU (iodine dose per contrast effect [IDCE]) and IDCE predicted by DL, body weight, lean body weight, and body surface area of patients. The model was tested on 52 cases for the male group (mean [SD] age, 63.7 ± 11.4) and 44 cases for the female group (mean [SD] age, 69.8 ± 11.6). Correlation coefficients between the actual and predicted IDCE were 0.607 for the male group and 0.412 for the female group, which were higher than the correlation coefficients between the actual IDCE and body weight (0.539 for male, 0.290 for female), lean body weight (0.563 for male, 0.352 for female), and body surface area (0.587 for male, 0.349 for female). The performance for predicting contrast effects by analyzing CT localizer radiographs with the DL model was at least comparable with conventional methods using the patient's body size, notwithstanding that no additional measurements other than CT localizer radiographs were required.

The Relevance of Time in Biological Scaling.

Various phenotypic traits relate to the size of a living system in regular but often disproportionate (allometric) ways. These "biological scaling" relationships have been studied by biologists for over a century, but their causes remain hotly debated. Here, I focus on the patterns and possible causes of the body-mass scaling of the rates/durations of various biological processes and life-history events, i.e., the "pace of life". Many biologists have regarded the rate of metabolism or energy use as the master driver of the "pace of life" and its scaling with body size. Although this "energy perspective" has provided valuable insight, here I argue that a "time perspective" may be equally or even more important. I evaluate various major ways that time may be relevant in biological scaling, including as (1) an independent "fourth dimension" in biological dimensional analyses, (2) a universal "biological clock" that synchronizes various biological rates/durations, (3) a scaling method that uses various biological time periods (allochrony) as scaling metrics, rather than various measures of physical size (allometry), as traditionally performed, (4) an ultimate body-size-related constraint on the rates/timing of biological processes/events that is set by the inevitability of death, and (5) a geological "deep time" approach for viewing the evolution of biological scaling patterns. Although previously proposed universal four-dimensional space-time and "biological clock" views of biological scaling are problematic, novel approaches using allochronic analyses and time perspectives based on size-related rates of individual mortality and species origination/extinction may provide new valuable insights.

Plasmonic dual-band waveguide with independently controllable band-notched characteristics

Abstract In this present paper, an investigation is conducted on a dual-band waveguide with independently controllable band-notched characteristics. The proposed slot structure, featuring a loaded gap, facilitates the operation of the plasmonic waveguide at two distinct frequency bands. Moreover, the working bandwidth of the waveguide can be flexibly adjusted through the use of varactors loaded across the gap. Notably, the dual band can be adjusted independently and flexibly by regulating the varactors. The measurement results demonstrate that the plasmonic filtering waveguide possesses excellent frequency selectivity and compact physical size, particularly concerning its real-time controllable notched-band response with the varactor voltages.