Vertical Structure Research Articles

Dark Current Suppression in Two‐dimensional Histamine Lead Iodine Perovskite Single Crystal for X‐ray Detection and Imaging

AbstractLead halide perovskites have emerged as attractive X‐ray detector materials, owing to properties such as strong X‐ray stopping power, excellent carrier transport, and high sensitivity. Additionally, they can be easily prepared by using solution‐based synthesis approaches. However, traditional 3D (three‐dimensional) perovskites X‐ray detectors have shown limited application due to high dark currents generated under bias voltage as a result of strong ion migration. In this work, an X‐ray detector with a vertical structure device is demonstrated using 2D (two‐dimensional) histamine lead halide perovskite single crystal HAPbI4 (HPI, HA = histamine). Due to the dielectric screening effect of diamine and the vertical structure of the HPI device, the fabricated detector shows a sensitivity of 7737 µC Gyair−1 cm−2 under a bias voltage of 30 V. Furthermore, the detector shows a sensitivity of 293 µC Gyair−1 cm−2 and detection limit of 51.38 nGyair s−1 without bias voltage, wherein the dark current is almost completely suppressed. All of these properties indicate the X‐ray detection device is a promising candidate for next‐generation optoelectronic applications.

Lithographically-defined cavities with high quality and purcell factors

Abstract We introduce and analyze a lithographically defined cavity (Li-cavity) incorporating a buried mesa defect in a planar vertical structure, which induces transverse photonic confinement while enabling compatibility with electrical injection. We systematically investigate the influence of key cavity parameters on optical behavior and fundamental properties using a comprehensive three-dimensional optical model. Our analysis reveals that the Li-cavity exhibits low optical scattering, resulting in high Q and Purcell factors, even at sub-wavelength dimensions. Furthermore, the Li-cavity supports single-mode operation within a broader aperture size range compared to conventional cavity designs, promising enhanced optical power of single-mode emission. Adequately designed structures demonstrate superior Q and Purcell factors at wavelength scale sizes,- outperforming conventional micropillar cavities. These improved properties and customizable device characteristics stem from a simple fabrication process that precisely controls the cavity size, shape, and optical mode. Superior characteristics, along with its adaptability to diverse materials, wavelengths, and photonic integration platforms, promise a broad range of applications and potential adaptation of this design to diverse photonic devices.

Enhancing Uniformity, Read Voltage Margin, and Retention in Three-Dimensional and Self-Rectifying Vertical Pt/Ta2O5/Al2O3/TiN Memristors.

This study introduces a Ta2O5-based self-rectifying memristor (SRM) with an Al2O3 interfacial layer adopted to improve switching uniformity, read voltage margin, and long-term retention. The Pt/Ta2O5/Al2O3/TiN (PTAT) device exhibits a 105 rectification ratio, 104 on/off ratio, 2 × 106 endurance, and retention of 104 s at 150 °C. A 3-layer 4 × 4 vertical resistive random access memory structure exhibits uniform switching parameters. The coefficient of variation (CV) for device-to-device measurements is 0.23 for the low resistance state (LRS) and 0.22 for the high resistance state (HRS), while for cycle-to-cycle measurements, the CV is 0.38 for the LRS and 0.11 for the HRS. Finally, the present study demonstrates the superior performance of the PTAT devices in the context of hardware-aware training for a fully connected neural network implementation. These advancements position the PTAT device as a promising candidate for high-density three-dimensional storage class memory and low-power neural networks, offering the consistent performance and reliability necessary for future high-density storage applications.

Study on the performance of hydrophilic curing agent and environmentally friendly non-pozzolanic filler for the development of self-curing self-compacting concrete.

Self-compacting concrete (SCC) is often used when compaction is difficult, requiring special attention to the curing process. However, traditional curing methods usually fail in practice. Despite taking precise measures to control water evaporation, surface water on vertical structure elements can still be problematic. To address these challenges, this study seeks to investigate the possibility of creating self-curing self-compacting concrete (SCSCC). Since the curing agent used has a significant impact on the production of SCSCC, this study examines the effects of using polyethylene glycol (PEG), a hydrophilic agent, at varying rates of 0.5%, 1%, 1.5%, and 2% on the fresh, hardened, and durability characteristics of the material. Additionally, to improve the sustainability properties of SCSCC, manufactured sand (M-sand) acquired from crushing rocks is used as a filler. Overall, the results indicate that the use of superplasticizer and M-sand is enough to achieve the required flowability for SCC mixtures without requiring specific fillers, and this method is effective in immediately controlling bleeding and segregation while maintaining the necessary compressive strength at all ages. The hardened properties of SCSCC were found to be improved by increasing the PEG content up to 1.5%, with an optimal range of 0.75% superplasticizer. Furthermore, the results demonstrate that the self-cured specimen, cured with PEG, has greater acid resistance than the conventionally cured one.

Detecting the Vertical Structure of Extreme Precipitation in the Headwater Area of Yellow River Using the Dual‐Frequency Precipitation Radar Onboard the Global Precipitation Measurement Mission

ABSTRACTIn the context of global warming, the rise in extreme precipitation events in high‐altitude headwater areas has introduced greater hydrological uncertainty. However, the limited understanding of the physical mechanisms driving extreme precipitation in these areas hinders efforts to mitigate the potential rise in future precipitation risks. This study analysed the extreme precipitation events in the headwater area of the Yellow River (HAYR) from May to September each year from 2015 to 2020 using satellite‐based data from Dual‐frequency Precipitation Radar (DPR) on the Global Precipitation Measurement (GPM) Core Observatory and Integrated Multi‐satellite Retrievals for GPM (IMERG). The results show that stratiform precipitation (SP) determines the spatial extent of extreme precipitation events, while convective precipitation (CP) largely affects the rainfall intensity. Statistical analysis from different extreme precipitation events indicates that the rain rate of CP is 2 to 3 times higher than that of SP, thus zones of intense precipitation in the study area are normally dominated by CP. Vertically, the topographic lifting in complex mountainous regions exerts opposite effects on the precipitation rates of SP and CP, weakening the precipitation intensity of SP while enhancing that of CP. The peak precipitation rate in the midstream and downstream regions is observed at approximately 5 km, whereas the upstream region displays a distinctive double‐peaked distribution, with one peak at 8.5 km and another near the surface. This study provides a better understanding of the interior structure evolution process of plateau precipitation, as well as the associated microphysical properties, and highlights some insights to improve microphysical parameterization in the future model developments.

Rural public investment and wage inequality under small‐scale agriculture modernization

Increasing rural public investment is crucial for sustainable rural development and can be an effective approach for reducing inequality. However, wage inequality has increased in some developing countries (e.g., China) after increasing fiscal support. This study explores how rural public investment influences skilled‐unskilled wage inequality by incorporating agricultural modernization in small‐scale agriculture. Agricultural modernization refers to introducing modern non‐agricultural intermediate inputs in agriculture. Owing to the small scale of agriculture, an intermediate sector, the agricultural producer service sector, is required to facilitate this process. We establish a three‐sector general equilibrium model with a two‐layer vertical production structure and investigate the effects of increased public investment in rural areas on the wage inequality between skilled and unskilled labour. The theoretical results show that while more rural public investment raises the wages of both skilled and unskilled labour, it also increases wage inequality. Overall, this study explains why inequality widens as rural public investment increases.

Pelagic cnidarian assemblages show range-edge effect at the boundary of ocean surface, as illustrated in the case of the Amazon River Plume.

The neuston layer represents a complex community inhabiting the interface where oceanographic and atmospheric processes interact. Here, our aim was to compare patterns in the distribution and abundance of cnidarian assemblages observed in the neuston to parallel patterns previously observed in epipelagic waters along the spread of the Amazon River Plume over the Western Equatorial Atlantic, to test if the neuston reflects the patterns of the overall community whose core of distribution is located in epipelagic waters or are shaped by specific surface processes. The results show that both initial hypothesis were false. Instead, the cnidarian assemblages showed range-edge effect at the major ecotone placed at the interface between ocean and atmosphere. I.e., when proximate to the superior limits of their three-dimensional geographic ranges, represented here by the neuston, the population of most observed species occur in lower abundance. Specifically at the portion of the continental shelf with influence of the Amazon River Plume, the range-edge effect seems to be more prominent. Such results suggests the core of the cnidarian populations inhabiting this habit may lie in the deeper hypoxic waters beneath the plume. In conclusion, due the marked vertical structure observed here, proper evaluations of spatial patterns in the structure of pelagic cnidarian communities should preferentially be grounded on stratified sampling.

The Vertical Structure of Turbulence Kinetic Energy Near the Arctic Sea‐Ice Surface

AbstractAtmospheric turbulence over the Arctic sea‐ice surface has been understudied due to the lack of observational data. In this study, we focus on the turbulence kinetic energy (TKE) over sea ice and distinguish its two different vertical structures, the “Surface” type and the “Elevated” type, using observations during the Multidisciplinary drifting Observatory for the Study of Arctic Climate expedition (MOSAiC). The “Surface” type has the maximum TKE near the surface (at 2 m), while the “Elevated” type has the maximum TKE at a higher level (6 m). The TKE budget analysis indicates that the “Elevated” type is caused by the increased shear production of TKE at 6 m. In addition, spectral analysis reveals that the contribution to TKE by horizontal large eddies is enhanced in the “Elevated” type. Finally, how the vertical structure of TKE affects the parameterization of turbulent momentum flux is discussed.

Experimental investigation of surface buoyant jet interactions with grid obstructions: implications for aquaculture

Freshwater inputs originating from terrestrial streams and gullies that discharge into quiescent, semi-enclosed coastal regions (such as estuaries, tidal inlets or lagoons), typically provide point sources of nutrients (e.g. nitrates, phosphates) and/or contaminants (e.g. pesticides, pathogens) that may have a deleterious impact on water quality. Many of these sheltered coastal regions also increasingly support aquaculture operations (e.g. finfish, shellfish, or seaweed farms), which can therefore be directly impacted by nutrient and contaminant inputs. Dynamically, these terrestrial freshwater inflows behave as surface buoyant jets or plumes within the coastal saline or brackish receiving waters, due to the salinity-induced density gradients. As such, the presence of infrastructure associated with aquaculture operations in sheltered coastal waters can provide obstruction to the propagation characteristics and residence times for these surface freshwater flows. Consequently, an improved physical understanding of the flow-structure interaction is clearly crucial to assessing the potential contamination risk of aquaculture products. The aim of the current study is therefore to explore, through scaled laboratory experiments within a channel-basin facility, the impact of physical obstruction induced by a vertical grid structure on the flow evolution of a 2D – 3D expanding, surface buoyant jet. Two grid obstructions with different solidity ratios are tested, along with surface gravity currents of different density excesses and freshwater inflows to infer the influence of different parametric conditions on the propagation, blockage and mixing characteristics of the surface current in the vicinity of the grid obstruction. Measurements of the velocity structure and thickness of the expanding surface plume are obtained by ultrasonic velocity profilers, while the density excess in the evolving plume is measured by micro-conductivity probes. Dye visualization results also show that, in the presence of the grid obstruction, the generation of shear-induced billows at the lower interface of the expanding surface current is largely blocked and a local deepening of the fresh-salt water interface in the immediate vicinity of the grid obstruction is observed. In this sense, the obstruction imposed by aquaculture infrastructure in coastal domains can have a considerable influence of the local turbulent mixing and vertical transfer of substances (e.g. nutrients and contaminants), but is likely to have relatively minimal impact in the final dispersion of the surface plume.

Consumer-Benefiting Transport Costs: The Role of Product Innovation in a Vertical Structure

Consumer-Benefiting Transport Costs: The Role of Product Innovation in a Vertical Structure

A Mixed-Pure Planar Heterojunction Structure of Active Layers for Efficient Sequential Blade-Coating Organic Solar Cells.

Precise modulating the vertical structure of active layers to boost charge transfer is an effective way to achieve high power conversion efficiencies (PCEs) in organic solar cells (OSCs). Herein, efficient OSCs with a well-controlled vertical structure are realized by a rapid film-forming method combining low boiling point solvent and the sequential blade-coating (SBC) technology. The results of grazing incident wide-angle X-ray scattering measurement show that the vertical component distribution is varied by changing the processing solvent. Novel characterization technique such as tilt resonant soft X-ray scattering is used to test the vertical structure of the films, demonstrating the dichloromethane (DCM)-processed film is truly planar heterojunction. The devices with chloroform (CF) processed upper layer show an increased mixed phase region compared to these devices with toluene (TL) or -DCM-, which is beneficial for improving charge generation and achieving a superior PCE of 17.36%. Despite significant morphological varies, the DCM-processed devices perform slightly lower PCE of 16.66%, which is the highest value in truly planar heterojunction devices, demonstrating higher morphological tolerance. This work proposes a solvent-regulating method to optimize the vertical structure of active layers through SBC technology, and provides a practical guidance for the optimization of the active-layer microstructure.

Dropsonde Observations of the Stable Marine Boundary Layer Beneath Atmospheric Rivers

Abstract An important source of errors in predicting landfalling atmospheric rivers (ARs), and their associated extreme precipitation and streamflow, are inaccuracies in model initial conditions in ARs offshore. These inaccuracies are particularly evident in the marine boundary layer (MBL) where the tendency of ARs to transport warm air poleward over progressively cooler SSTs generates a stable MBL (SMBL). The SMBL’s vertical structure and key modulating processes are documented using >1000 dropsondes along 99 transects of ARs from the AR Reconnaissance and CalWater field campaigns. The SMBL depth, modulated by sensible heat loss to the ocean, is typically 300–800 m in the AR core, with vertical wind shears ranging from 5–50 m s−1 km−1, representing a highly variable decoupling of the AR aloft from conditions at the ocean surface. Simulated backward air parcel trajectories originating from dropsonde locations within the AR core are used to calculate the 24-h change in SST experienced by an air parcel (DSST24) beneath each AR. The DSST24 varies from −13°C to +2°C and is directly related to the strength of the AR and its orientation relative to the SST gradient. The DSST24, therefore, distinguishes weak and strong decoupling regimes (WDR, SDR). In SDR cases, relative to WDR cases, the SMBL is characterized by greater sensible heat loss to the ocean, as well as stronger static stability, vertical wind shear, low-level jet, and horizontal water vapor transport. In SDR cases, the SMBL is deeper in the core than in adjacent warm and cold sectors.

Unveiling Cloud Vertical Structures over the Interior Tibetan Plateau through Anomaly Detection in Synergetic Lidar and Radar Observations

Unveiling Cloud Vertical Structures over the Interior Tibetan Plateau through Anomaly Detection in Synergetic Lidar and Radar Observations

Flexible Thermoelectric BiSbTe/Carbon Paper/BiSbTe Sandwiches for Bimode Temperature‐Pressure Sensors

AbstractBimode temperature‐pressure sensors hold significant promise in personal health monitoring, wearables and robotic signal detection. Traditional bimode sensors typically combine two independent sensors, leading to fabrication complexity. This study develops a bimode temperature‐pressure sensor by using a facile electrodeposition method to create sandwiched BiSbTe/Carbon Paper/BiSbTe thin films and stacking them to a vertical structure. It demonstrates high sensitivity for temperature sensing, capable of detecting temperature difference as low as 1 K, and a rapid response time of 0.92 s due to a vertical structure. Utilizing its thermoelectric mechanism, the sensor achieves self‐powered sensing for finger touch and respiration states. Furthermore, its island‐like contact surface ensures high sensitivity with an extremely fast response time of 0.17 s, by rapidly changing contact resistance under pressure, allowing it to detect various human behaviors, including body movements and micro‐expressions. Beyond its sensing capabilities, the film excels in flexibility, electromagnetic interference shielding, and stability, presenting significant potential for integration into self‐powered electronic skin systems for health monitoring, wearables, artificial intelligence, and other electronic skin applications.

Upper-ocean changes with hurricane-strength wind events: a study using Argo profiles and an ocean reanalysis

Abstract. As the Earth's climate warms, the intensity and rain rate of tropical cyclones (TCs) is projected to increase. TCs intensify by extracting heat energy from the ocean; hence, a better understanding of upper-ocean changes with the TC passage is helpful to improve our understanding of air–sea interactions during and after the event. This work uses Argo float observations and the HYbrid Coordinate Ocean Model (HYCOM) ocean reanalysis to describe characteristics of upper-ocean changes with hurricane-strength wind events. We study the association of these changes with the vertical structure of the salinity profile before the event, i.e., increasing versus decreasing with depth. We also study the contribution of changes in salinity to upper-ocean density changes in each case. Results show that in regions where pre-event salinity increases with depth there is a corresponding statistically significant increase in upper-ocean salinity; vice versa, we observe a significant decrease in upper-ocean salinity in regions where pre-event salinity decreases with depth. Consistent with previous studies, temperature decreases in both regions. As near-surface temperature decreases, upper-ocean density increases, and the increase is larger where pre-event salinity increases with depth. Changes in upper-ocean properties from Argo and HYCOM are overall consistent with wind-driven vertical mixing of near-surface waters with colder and higher-salinity (or lower-salinity) waters below. Resulting changes in ocean stratification have implications for air–sea interactions during and after the event, with potential impacts on weather events that follow.

Experimental study on seismic damage of SRC-RC vertical hybrid structure

In order to analyze the seismic performance of the SRC-RC vertical hybrid structure, three substructure models were designed, and the key data of structural performance, such as hysteresis curve, skeleton curve, bearing capacity, energy dissipation of structure, residual deformation and damage degree were obtained by carrying out low cyclic loading tests. According to the tests, the plastic development at the column base was delayed because of the reinforcement of section steel, and the plastic development at beam end was much more sufficient, which benefited the beam hinge mechanism in the transition area, so that the transition area has better energy dissipation capacity and deformation capacity. Based on the more sufficient lateral displacement of beam hinge, the beams suffered bending deformation obviously, and interaction between the beams and the infilled wall was significant, which led to a more complex interface force transmission, so the bending cracks and the shearing cracks were densely distributed along the full length of the beam. Meanwhile, the reinforcement of section steel not only improved the deformation capacity of the models but also resulted in more significant damage difference in positive and negative loading. To quantitatively evaluate the damage level, a seismic damage index system was proposed, including displacement damage degree, bearing capacity damage degree and residual deformation index, which reflect the increment of deformation caused by structural damage, the deterioration of bearing capacity and the residual deformation, respectively. It is suggested that the structural failure should be defined respectively under different modes: For the strength degradation behavior mode and ductility behavior mode, structural failure should be confirmed if the load reduces to 0.90 and 0.85 times of the peak load, respectively; and for the brittle behavior mode, the frame is considered to fail when the load reaches the peak without considering the structural performance after the peak load.

Viscoelastic-Support-Layer-Based Macroscopic Conformal Transfer of van der Waals Materials Compatible with Plasmonic Application.

This study showcases the conformal geometries of van der Waals materials with metallic structures utilizing viscoelastic support layers. Mechanically exfoliated nanometer-thick graphite flakes were transferred onto metal structures with various side slopes using two different polymers: polycarbonate (PC) and polyethylene (PE). We proposed a morphology-based evaluation of the macroscale conformity that can contribute to the selection of a proper support layer. Although both support layers ensured high conformity on the sloped side, the PE layer offered superior conformity on the vertical metal structure. To further investigate the impact of conformal structures, we compared the terahertz transmission changes of a metal bowtie antenna before and after transferring graphite onto the bowtie gap for two distinct conformal structures. The conformity of graphite to the metal gap structure significantly influenced the optical response in the terahertz frequency regime. This suggests that the conformal structuring technique can be leveraged in various terahertz devices composed of metals and van der Waals materials, opening avenues for quantitative analysis in light-matter interactions.

Auroral 3D structure retrieval from the Juno/UVS data

Context. Jovian auroras, the most powerful in the Solar System, result from the interaction between the magnetosphere and atmosphere of Jupiter. While the horizontal morphology of these phenomena has been widely studied, their vertical structure, determined by the penetration depth of the magnetospheric electron into the auroral regions, remains relatively unexplored. Previous observations, including those from the Hubble Space Telescope (HST), have addressed this question to a limited extent. Aims. In this study we aim to map the vertical structure of Jovian auroral emissions. Methods. Using observations from Juno’s UltraViolet Spectrograph (UVS), we examined the vertical structure of the auroral emissions. Building on a recent study of auroral energy mapping based on UVS observations that mapped the average energy of precipitating electrons in the Jovian auroral regions, we find a relationship between this average energy and the volume emission rate (VER) of H2 for two types of electron energy distributions: monoenergetic and a kappa distribution with κ = 2.5. Results. Using brightness maps, we derived the 3D VER structure of Jovian auroras in both northern and southern regions, across multiple spacecraft perijoves (PJs). By considering the example of PJ11, we find that the average altitude of the VER peak in the polar emission region is approximately ~250 km for the monoenergetic distribution case and ~190 km for kappa distribution case. In the main emission region, we find that the average altitude of the VER peak is approximately ~260 km for the case of monoenergetic distribution and ~197 km for kappa distribution case. For the other PJs, we obtained results that are very similar to those of PJ11. Conclusions. Our findings are, on average, consistent with measurements from the Galileo probe and the HST observations. This study contributes to a better understanding of the complexity of Jovian auroras and highlights the importance of using Juno observations when probing their vertical structure. Considering the variability in the κ parameter in the auroral region, we also studied the impact of this variability on the vertical structure of the auroral emission. This sensitivity study reveals that the influence of the κ parameter on our results was very weak. However, the impact of the κ variability on the VER amplitude shows that there is an influence on the thermal structure and chemical composition of the atmosphere in the auroral regions.

Future Changes in the Vertical Structure of Severe Convective Storm Environments over the U.S. Central Great Plains

Abstract The effect of warming on severe convective storm potential is commonly explained in terms of changes in vertically integrated (“bulk”) environmental parameters, such as CAPE and 0–6-km shear. However, such events are known to depend on the details of the vertical structure of the thermodynamic and kinematic environment that can change independently of these bulk parameters. This work examines how warming may affect the complete vertical structure of these environments for fixed ranges of values of high CAPE and bulk shear, using data over the central Great Plains from two high-performing climate models (CNRM and MPI). To first order, projected changes in the vertical sounding structure are consistent between the two models: the environment warms approximately uniformly with height at constant relative humidity, and the shear profile remains relatively constant. The boundary layer becomes slightly drier (−2% to 6% relative humidity) while the free troposphere becomes slightly moister (+1% to 3%), with a slight increase in moist static energy deficit aloft with stronger magnitude in CNRM. CNRM indicates enhanced low-level shear and storm-relative helicity associated with stronger hodograph curvature in the lowest 2 km, whereas MPI shows near-zero change. Both models strongly underestimate shear below 1 km compared to ERA5, indicating large uncertainty in projecting subtle changes in the low-level flow structure in climate models. The evaluation of the net effect of these modest thermodynamic and kinematic changes on severe convective storm outcomes cannot be ascertained here but could be explored in simulation experiments. Significance Statement Severe thunderstorms and tornadoes cause substantial damage and loss of life each year, which raise concerns about how they may change as the world warms. We typically use a small number of common atmospheric parameters to understand how these localized events may change with climate change. However, climate change may alter the weather patterns that produce these events in ways not captured by these parameters. This work examines how climate change may alter the complete vertical structure of temperature, moisture, and wind and discusses the potential implications of these changes for future severe thunderstorms and tornadoes.

Mesoscale eddy in situ observation and characterization via underwater glider and complex network theory.

Mesoscale eddies have attracted increased attention due to their central role in ocean energy and mass transport. The observations of their three-dimensional structure will facilitate the understanding of nonlinear eddy dynamics. In this paper, we propose a novel framework, the mesoscale eddy characterization from ordinal modalities recurrence networks method (MeC-OMRN), that utilizes a Petrel-II underwater glider for in situ observations and vertical structure characterization of a moving mesoscale eddy in the northern South China Sea. First, higher resolution continuous observation profile data collected throughout the traversal by the underwater glider are acquired and preprocessed. Subsequently, we analyze and compute these nonlinear data. To further amplify the hidden structural features of the mesoscale eddy, we construct ordinal modalities sequences rich in spatiotemporal characteristics based on the measured vertical density of the mesoscale eddy. Based on this, we employ ordinal modalities recurrence plots (OMRPs) to depict the vertical structure inside and outside the eddy, revealing significant differences in the OMRPs and the unevenness of density stratification within the eddy. To validate our intriguing findings from the perspective of complex network theory, we build the multivariate weighted ordinal modalities recurrence networks, through which network measures exhibit a more random distribution of vertical density stratification within the eddy, possibly due to more intense vertical convection and oscillations within the eddy's seawater micelles. These framework and intriguing findings are anticipated to be applied to more data-driven in situ observation tasks of oceanic phenomena.