Large Field Research Articles

The dominance and growth of shallow groundwater resources in continuous permafrost environments

Water is a limited resource in Arctic watersheds with continuous permafrost because freezing conditions in winter and the impermeability of permafrost limit storage and connectivity between surface water and deep groundwater. However, groundwater can still be an important source of surface water in such settings, feeding springs and large aufeis fields that are abundant in cold regions and generating runoff when precipitation is rare. Whether groundwater is sourced from suprapermafrost taliks or deeper regional aquifers will impact water availability as the Arctic continues to warm and thaw. Previous research is ambiguous about the role of deep groundwater, leading to uncertainty regarding Arctic water availability and changing water resources. We analyzed chemistry and residence times of spring, stream, and river waters in the continuous permafrost zone of Alaska, spanning the mountains to the coastal plain. Water chemistry and age tracers show that surface waters are predominately sourced from recent precipitation and have short (<50 y) subsurface residence times. Remote sensing indicates trends in the areal extent of aufeis over the last 37 y, and correlations between aufeis extent and previous year summer temperature. Together, these data indicate that surface waters in continuous permafrost regions may be impacted by short flow paths and shallow suprapermafrost aquifers that are highly sensitive to climatic and hydrologic change over annual timescales. Despite the lack of connection to regional aquifers, continued warming and permafrost thaw may promote deepening of the shallow subsurface aquifers and creation of shallow taliks, providing some resilience to Arctic freshwater ecosystems.

A novel calibration method based on fixed multi-plane targets for cameras with large field of view

For camera calibration with large field of view (FOV), the accuracy is impacted by the size of the calibration targets. Considering the challenges associated with producing and carrying large targets, existing methods resort to using small targets to achieve calibration without high accuracy. In order to solve this problem, a photogrammetric calibration method based on the fixed multi-plane targets (FMPT) is proposed in this paper for cameras with large FOV. The FMPT is composed by multiple identical small planar targets (PTs), with fixed pose transformation relationships among PTs. The proposed calibration method involves the following main steps. Firstly, the camera is moved several times to capture a series of images of FMPT. Secondly, the fixed pose transformation matrices of different small PTs in FMPT are calculated through the initial parameters of camera. Finally, calibration based on photogrammetry is conducted, with a continuous optimization of camera intrinsic and extrinsic parameters based on the multiple 2D and 3D constraint in the FMPT. Simulation and real data experiments show that the calibration accuracy using the proposed method is much higher than that using a small target, and sightly higher than that using a large target. Furthermore, the experiments demonstrate the robust stability of this method, maintaining high calibration accuracy even in the presence of increased noise and error in target production.

Imaging of human parafoveal area with large field of view in adaptive optics line scanning ophthalmoscope

The parafoveal area, with its high concentration of photoreceptors and fine retinal capillaries, is crucial for central vision and often exhibits early signs of pathological changes. The current adaptive optics scanning laser ophthalmoscope (AOSLO) provides an excellent tool to acquire accurate and detailed information about the parafoveal area with cellular resolution. However, limited by the scanning speed of two-dimensional scanning, the field of view (FOV) in the AOSLO system was usually less than or equal to 2∘, and the stitching for the parafoveal area required dozens of images, which was time-consuming and laborious. Unfortunately, almost half of patients are unable to obtain stitched images because of their poor fixation. To solve this problem, we integrate AO technology with the line-scan imaging method to build an adaptive optics line scanning ophthalmoscope (AOLSO) system with a larger FOV. In the AOLSO, afocal spherical mirrors in pairs are nonplanar arranged and the distance and angle between optical elements are optimized to minimize the aberrations, two cylinder lenses are orthogonally placed before the imaging sensor to stretch the point spread function (PSF) for sufficiently digitizing light energy. Captured human retinal images show the whole parafoveal area with [Formula: see text] FOV, 60[Formula: see text]Hz frame rate and cellular resolutions. Take advantage of the 5∘ FOV of the AOLSO, only 9 frames of the retina are captured with several minutes to stitch a montage image with an FOV of [Formula: see text], in which photoreceptor counting is performed within approximately 5∘ eccentricity. The AOLSO system not only provides cellular resolution but also has the capability to capture the parafoveal region in a single frame, which offers great potential for noninvasive studying of the parafoveal area.

The Bhargava Greedoid as a Gaussian Elimination Greedoid

Inspired by Manjul Bhargava's theory of generalized factorials, Grinberg and Petrov have defined the Bhargava greedoid - a greedoid (a matroid-like set system on a finite set) assigned to any "ultra triple" (a somewhat extended variant of a finite ultrametric space). Here we show that the Bhargava greedoid of a finite ultra triple is always a Gaussian elimination greedoid over any sufficiently large (e.g., infinite) field; this is a greedoid analogue of a representable matroid. We find necessary and sufficient conditions on the size of the field to ensure this.

Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE)

Abstract Convective clouds play an important role in the Earth’s climate system and are a known source of extreme weather. Gaps in our understanding of convective vertical motions, microphysics, and precipitation across a full range of aerosol and meteorological regimes continue to limit our ability to predict the occurrence and intensity of these cloud systems. Towards improving predictability, the National Science Foundation (NSF) sponsored a large field experiment entitled “Experiment of Sea Breeze Convection, Aerosols, Precipitation, and Environment (ESCAPE).” ESCAPE took place between 30 May - 30 Sept. 2022 in the vicinity of Houston, TX because this area frequently experiences isolated deep convection that interacts with the region's mesoscale circulations and its range of aerosol conditions. ESCAPE focused on collecting observations of isolated deep convection through innovative sampling, and on developing novel analysis techniques. This included the deployment of two research aircraft, the National Research Council of Canada Convair-580 and the Stratton Park Engineering Company Learjet, which combined conducted 24 research flights from 30 May to 17 June. On the ground, three mobile X-band radars, and one mobile Doppler lidar truck equipped with soundings, were deployed from 30 May to 28 June. From 1 August to 30 Sept. 2022, a dual-polarization C-band radar was deployed and operated using a novel, multi-sensor agile adaptive sampling strategy to track the entire lifecycle of isolated convective clouds. Analysis of the ESCAPE observations has already yielded preliminary findings on how aerosols and environmental conditions impact the convective life cycle.

High energy storage properties of (Nb0.5La0.5)4+ complex-ion modified (Ba0.85Ca0.15)(Zr0.10Ti0.90)O3 ceramics

In this work, a traditional solid-state method was adopted to prepare dense Ba[Formula: see text]Ca[Formula: see text][(Zr[Formula: see text]Ti[Formula: see text])[Formula: see text]–(Nb[Formula: see text]La[Formula: see text])x]O3(BCZT–xNL) lead-free relaxation ferroelectrics with excellent energy storage performance (ESP). Remarkably, a large breakdown field strength of BDS ([Formula: see text][Formula: see text]kV/cm) resulting from decreased grain size by double ions doping at the B-site was achieved in BCZT–xNL ceramics. Especially, the BCZT–0.12NL ceramic displays a good recoverable energy density ([Formula: see text]) of 3.1[Formula: see text]J/cm3, a high efficiency of 86.7% ([Formula: see text]) and a superior fatigue resistance, as well as a superior charge–discharge performance ([Formula: see text][Formula: see text]A/cm2, [Formula: see text][Formula: see text]MW/cm3, [Formula: see text][Formula: see text]J/cm3, [Formula: see text][Formula: see text]ns) and good thermal stability. Besides, upon NL doping, the FE to RFE phase transition results in a dielectric behavior traversing the relaxation phase ([Formula: see text]) accompanied by frequency dispersion, which is beneficial to improve ESP. The superior ESP in this work indicates that BCZT–0.12[Formula: see text]NL ceramics are a promising candidate used in energy storage capacitors.

Near‐Infrared Metalens Empowered Dual‐Mode High Resolution and Large FOV Microscope

AbstractThe spiral phase contrast microscope can clearly distinguish the morphological information of the low contrast objects (i.e., biological samples) owing to the isotropic edge‐enhancement effect, while the bright field microscope can image the overall morphology of amplitude objects. However, the imaging resolution, magnification, and field of view of conventional spiral phase contrast microscopes based on 4f filtering configuration are limited by the system's complexity. Here, compact dual‐mode microscopes working at near‐infrared using the engineered metalens are reported, which can be tuned between the spiral phase contrast imaging and bright field imaging by polarization control. The metalens combine the high‐resolution objective lens and polarization‐controlled phase filter into a single‐layer nanofins array. Two infinity‐corrected microscope systems are demonstrated to achieve subwavelength resolution (0.7λ), large magnification (58X), and large field of view (600 × 800 µm). Unstained onion epidermal is imaged by the microscope to show the dual‐mode imaging ability for the biological sample. Finally, a singlet dual‐mode microscope system is demonstrated to show the edge‐detection application for industrial standards. These results can open new opportunities in applications of biological imaging, industrial machine vision, and semiconductor inspection.

A method for building extraction in remote sensing images based on swintransformer

ABSTRACT Remote sensing image building segmentation, which is essential in land use and urban planning, is evolving with advancements in deep learning. Conventional methods using convolutional neural networks face limitations in integrating local and global information and establishing long-range dependencies, resulting in suboptimal segmentation in complex scenarios. This paper proposes LMSwin_PNet, a novel segmentation network that addresses the SwinTransformer encoder's deficiency in local information processing through a local feature extraction module. Additionally, it features a multiscale nonparametric merging attention module to enhance feature-channel correlations. The network also incorporates the pyramid large-kernel convolution module, replacing the traditional 3 × 3 convolution in the decoder with multibranch large-kernel convolution, thereby achieving a large receptive field and detailed information capture. Comparative analyses on three public building datasets demonstrated the model's superior segmentation performance and robustness. The results show that LMSwin_PNet produced outputs closely matching labels, showing its potential for broader application in remote sensing image segmentation tasks. It achieved achieving an IoU of 72.35% on the Massachusetts Building Dataset, 91.30% on the WHU Building Dataset, and 78.99% on the Inria aerial-image building dataset. The source code will be freely available at https://github.com/ziyanpeng/pzy.

Research on key technology of cooled infrared bionic compound eye camera based on small lens array

Traditional 2D imaging technologies are limited by the need for a large field of view and their sensitivity to small target motion. Inspired by the characteristics of insect compound eye structure, we propose an infrared bionic compound eye camera based on a small lens array. The camera is composed of 61 small lens arrays mounted on a curved spherical shell and a relay optical system. The imaging device is a high-performance cooled mid-wave infrared detector. This is an innovative design for an infrared biomimetic compound eye camera system that provides a wide field of view and all-day detection capability. Aimed to meet the specified requirements. The optical system achieves a 100% cold-membrane match between the infrared optical system and the cooled detector, and the relay optical system optimizes the large-field aberration by introducing a higher-order aspheric surface and modifying the geometric surface of the lenses. Our entire system enables an observation field angle of 108∘×108∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$108^\\circ \ imes 108^\\circ$$\\end{document}. The experiments showed that the image quality of the system is high, each ommatidium was effective within the imaging range of the compound eye camera, resulting in an improved signal-to-noise ratio in various scenes.

Quantitative phase image stitching guided by reconstructed intensity images in one-shot double field of view multiplexed digital holographic microscopy

In digital holographic microscopy (DHM), achieving large field of view (FOV) imaging while maintaining high resolution is critical for quantitative phase measurements of biological cell tissues and micro-nano structures. We present a quantitative phase image stitching guided by reconstructed intensity images in one-shot double FOV multiplexed DHM. Double FOVs are recorded simultaneously through frequency division multiplexing; intensity feature pairs are accurately extracted by multi-algorithm fusion; aberrations and non-common baselines are effectively corrected by preprocessing. Experimental results show that even if phase images have coherent noise, complex aberrations, low overlap rate and large size, this method can achieve high-quality phase stitching.

Impact of foliar application of iron and zinc fertilizers on grain iron, zinc, and protein contents in bread wheat (Triticum aestivum L.)

Impact of foliar application of iron and zinc fertilizers on grain iron, zinc, and protein contents in bread wheat (Triticum aestivum L.)

Deep tomography for the three-dimensional atmospheric turbulence wavefront aberration

Multiconjugate adaptive optics (MCAO) can overcome atmospheric anisoplanatism to achieve high-resolution imaging with a large field of view (FOV). Atmospheric tomography is the key technology for MCAO. The commonly used modal tomography approach reconstructs the three-dimensional atmospheric turbulence wavefront aberration based on the wavefront sensor (WFS) detection information from multiple guide star (GS) directions. However, the atmospheric tomography problem is severely ill-posed. The incomplete GS coverage in the FOV coupled with the WFS detection error significantly affects the reconstruction accuracy of the three-dimensional atmospheric turbulence wavefront aberration, leading to a nonuniform aberration detection precision over the whole FOV. We propose an efficient approach for achieving accurate atmospheric tomography to overcome the limitations of the traditional modal tomography approach. We employed a deep-learning-based approach to the tomographic reconstruction of the three-dimensional atmospheric turbulence wavefront aberration. We propose an atmospheric tomography residual network (AT-ResNet) that is specifically designed for this task, which can directly generate wavefronts of multiple turbulence layers based on the Shack-Hartmann (SH) WFS detection images from multiple GS directions. The AT-ResNet was trained under different turbulence intensity conditions to improve its generalization ability. We verified the performance of the proposed approach under different conditions and compared it with the traditional modal tomography approach. The well-trained AT-ResNet demonstrates a superior performance compared to the traditional modal tomography approach under different atmospheric turbulence intensities, various turbulence layer distributions, higher-order turbulence aberrations, detection noise, and reduced GSs conditions. The proposed approach effectively addresses the limitations of the modal tomography approach, leading to a notable improvement in the accuracy of atmospheric tomography. It achieves a highly uniform and high-precision wavefront reconstruction over the whole FOV. This study holds great significance for the development and application of the MCAO technology.

Calibration method for binocular vision system with large field of view based on small target image splicing

In vision measurement, camera calibration has a significant impact on measurement precision. The classical target-based calibration methods require the target to occupy more than one-third of the field of view. A small-size target that does not meet the requirements results in poor calibration accuracy, while an appropriate large-size target is difficult to manufacture and inconvenient to operate. In view of the above problem, we propose a flexible and accurate calibration method based on small target image splicing to calibrate the binocular vision system with a large field of view. The spliced images and virtual large targets are constructed to extend the target size, providing better flexibility for calibration. Moreover, an optimization objective function integrating two constraints in the imaging plane and measurement space is presented to improve the calibration accuracy during the parameter optimization process. The simulation experiments and actual experiments are carried out to test the performance of the proposed method. The results demonstrate that the calibration accuracy of the proposed method using a small target is equivalent to that of Zhang’s method using a large target. Additionally, when using a same-size target, the parameter error of the proposed method is less than that of Zhang’s method, and the proposed method reduces the distance measurement error from 1.169 mm to 0.208 mm compared to Zhang’s method.

Acoustofluidic scanning fluorescence nanoscopy with a large field of view

Large-field nanoscale fluorescence imaging is invaluable for many applications, such as imaging subcellular structures, visualizing protein interactions, and high-resolution tissue imaging. Unfortunately, conventional fluorescence microscopy requires a trade-off between resolution and field of view due to the nature of the optics used to form the image. To overcome this barrier, we developed an acoustofluidic scanning fluorescence nanoscope that simultaneously achieves superior resolution, a large field of view, and strong fluorescent signals. The acoustofluidic scanning fluorescence nanoscope utilizes the superresolution capabilities of microspheres that are controlled by a programmable acoustofluidic device for rapid fluorescence enhancement and imaging. The acoustofluidic scanning fluorescence nanoscope resolves structures that cannot be resolved with conventional fluorescence microscopes with the same objective lens and enhances the fluorescent signal by a factor of ~5 without altering the field of view of the image. The improved resolution realized with enhanced fluorescent signals and the large field of view achieved via acoustofluidic scanning fluorescence nanoscopy provides a powerful tool for versatile nanoscale fluorescence imaging for researchers in the fields of medicine, biology, biophysics, and biomedical engineering.

Enhanced photovoltaic response in WSe2 photodetector with asymmetric two-dimensional contacts

Asymmetric contact pairs with different work functions provide an efficient method to extract photogenerated carriers in optoelectrical devices. Specifically, vertical optoelectrical devices based on two-dimensional (2D) materials utilize graphene layers as the bottom and top contacts. Whereas an additional terminal is required for electrostatic doping in either top or bottom graphene to enlarge the built-in electric field. Herein, we present an enhanced photovoltaic response in a vertical WSe2 photodetector utilizing asymmetric 2D contacts. A graphite layer and a degenerate SnSe2 are used as the top and bottom contacts, respectively, with a significant difference in their work functions. By establishing a large built-in electric field across the vertical WSe2 layer, a strong photovoltaic effect is achieved, resulting in an open-circuit voltage of 0.37 V and a short-circuit current of 0.42 μA under 532 nm illumination. The device shows high-performance photodetection characteristics, with a responsivity of 32.04 A W−1, external quantum efficiency of 7475%, and specific detectivity of 3.61 × 1012 Jones. Furthermore, the device can generate a maximum output electrical power of 70.9 nW, enabling a high-power conversion efficiency of 3.5%.

Animal PET scanner with a large field of view is suitable for high-throughput scanning of rodents.

In preclinical studies, high-throughput positron emission tomography (PET) imaging, known as simultaneous multiple animal scanning, can reduce the time spent on animal experiments, the cost of PET tracers, and the risk of synthesis of PET tracers. It is well known that the image quality acquired by high-throughput imaging depends on the PET system. Herein, we investigated the influence of large field of view (FOV) PET scanner on high-throughput imaging. We investigated the influence of scanning four objects using a small animal PET scanner with a large FOV. We compared the image quality acquired by four objects scanned with the one acquired by one object scanned using phantoms and animals. We assessed the image quality with uniformity, recovery coefficient (RC), and spillover ratio (SOR), which are indicators of image noise, spatial resolution, and quantitative precision, respectively. For the phantom study, we used the NEMA NU 4-2008 image quality phantom and evaluated uniformity, RC, and SOR, and for the animal study, we used Wistar rats and evaluated the spillover in the heart and kidney. In the phantom study, four phantoms had little effect on imaging quality, especially SOR compared with that for one phantom. In the animal study as well, four rats had little effect on spillover from the heart muscle and kidney cortex compared with that for one rat. This study demonstrated that an animal PET scanner with a large FOV was suitable for high-throughput imaging. Thus, the large FOV PET scanner can support drug discovery and bridging research through rapid pharmacological and pathological evaluation.

Manipulation of Gaseous Ions with Acoustic Fields at Atmospheric Pressure.

The ability to controllably move gaseous ions is an essential aspect of ion-based spectrometry (e.g., mass spectrometry and ion mobility spectrometry) as well as materials processing. At higher pressures, ion motion is largely governed by diffusion and multiple collisions with neutral gas molecules. Thus, high-pressure ion optics based on electrostatics require large fields, radio frequency drives, complicated geometries, and/or partially transmissive grids that become contaminated. Here, we demonstrate that low-power standing acoustic waves can be used to guide, block, focus, and separate beams of ions akin to electrostatic ion optics. Ions preferentially travel through the static-pressure regions ("nodes") while neutral gas does not appear to be impacted by the acoustic field structure and continues along a straight trajectory. This acoustic ion manipulation (AIM) approach has broad implications for ion manipulation techniques at high pressure, while expanding our fundamental understanding of the behavior of ions in gases.

Application of an improved wide–narrow-band hybrid ANC algorithm in a large commercial vehicle cabine

In recent years, active noise reduction technology has become a research hotspot. However, most active noise reduction technologies are developed based on passenger vehicles and are not implemented in large commercial vehicles. The large commercial vehicle sound field space is large, the traditional active noise reduction method is difficult to implement. In order to explore this problem, this paper proposes an improved active noise control method for commercial vehicles: (1) based on the traditional notch filter, a notch FxLMS algorithm based on speed smoothing is proposed; (2) on the basis of the traditional wire–narrowband hybrid ANC algorithm, the reference signal weighting technology is introduced into the wide-band subsystem, and the notch FxLMS algorithm based on speed smoothing is used as the narrowband subsystem, so as to propose an improved wire-narrowband hybrid ANC algorithm. With the help of MATLAB, the simulation model of the designed algorithm is established, and the collected commercial vehicle test noise data is used as the reference signal to simulate and verify the proposed algorithm. The results show that the proposed method has certain practicability.

High Energy Storage Performance in BiFeO3-Based Lead-Free High-Entropy Ferroelectrics.

Dielectric capacitors are widely used in advanced electrical and electronic systems due to the rapid charge/discharge rates and high power density. High comprehensive energy storage properties are the ultimate ambition in the field of application achievements. Here, the high-entropy strategy is proposed to design and fabricate single-phase homogeneous (Bi0.5Ba0.1Sr0.1Ca0.2Na0.1)(Fe0.5Ti0.3Zr0.1Nb0.1)O3 ceramic, the hierarchical heterostructure including rhombohedral-tetragonal multiphase nanoclusters and locally disordered oxygen octahedral tilt can lead to the increased dielectric relaxation, diffused phase transition, diverse local polarization configurations, grain refinement, ultrasmall polar nanoregions, large random field, delayed polarization saturation and improved breakdown field. Accordingly, a giant Wrec ≈13.3 J cm-3 and a high η ≈78% at 66.4kV mm-1 can be simultaneously achieved in the lead-free high-entropy BiFeO3-based ceramic, showing an obvious advantage in overall energy-storage properties over BiFeO3-based lead-free ceramics. Moreover, an ultrafast discharge rate (t0.9 = 18ns) can be achieved at room temperature, concomitant with favorable temperature stability in the range of 20-160 °C, due to the enhanced diffuse phase transition and fast polarization response. This work provides a feasible pathway to design and generate dielectric materials exhibiting high comprehensive energy-storage performance.

APPLICATION OF HYDROGELS FOR WATER SHUTOFF TREATMENTS. Message No. 2

The article analyzes the use of hydrogels with nanoparticle additives for well water shutoff, as well as the development of a mathematical apparatus for hydrodynamic modeling of water shutoff operations. One of the most significant trends in the development of gel forming compounds for well water shutoff in the last 10 years has been the use of nanocomposites. The base polymers for nanocomposites used for water shutoff operations are either synthetic or biopolymer origin. The article highlights the novelty and prospects of using nanoparticles in sealing compositions. Various nanocomponent additives are used to increase the success of the use of hydrogel polymer systems in order to limit water inflow and expand the scope of their application in complicated reservoir conditions. These include carbon and mineral nanoparticles, which increase the stability and strength of crosslinked gels in formation conditions.In this paper, we consider the optimization of the repair and insulation operations design using gels for well water shutoff using mathematical modeling, which helps to justify the volume of hydrogel injection and calculate the necessary pressure gradients at which the sealing screen remains stable. The paramount importance of determining the source of well flooding is emphasized, depending on which the processing design is already being built, and appropriate materials are selected; trends in the development of repair and insulation operations at the present stage are traced. Based on the results of the implementation of the proposed model by numerical methods, the authors constructed diagrams of the stability of the waterproofing screen depending on the fracture width, screen size, gel injection rate and reservoir permeability. The technique proposed in the work allows to correctly select and optimize the technological parameters of the operation to maintain the stability of the screen in specific geological conditions.Mathematical modeling allows us to strictly justify the volume of injection of the gel screen, increase the technological and economic efficiency of the process, and in large fields — to rank wells according to the priority of processing. Oilfield practice in various regions of the country fully confirms the main conclusions made in this review article. Preliminary mathematical modeling and the introduction of microdispersions into gel formulations can significantly increase the efficiency of water shutoff operations. The next step in the development of water insulation technologies is the use of nanodispersions, which look very promising in laboratory modeling and are no longer exotic materials with unrealistic cost.