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2,426
result(s) for
"Vertical orientation"
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Force analysis and improvement of main transformer bushing terminal structure
2024
After investigation, it was found that due to natural environmental conditions such as rain and snow temperature, equipment such as down conductor above the terminals, and natural swings of wires, the terminal blocks of the down conductor bushing on the high voltage side of the main transformer of a 500kV substation will deteriorate and deform. Following the force analysis and experiment on the down conductor bushing terminal block on the high voltage side of the main transformer, it is found that the weak structure of the bushing terminal block lies in the vertical orientation of the terminal and the connection point of the transverse structure, and its horizontal external force limit value is 1.91KN. In this paper, it was finally decided to improve the terminal structure by erecting diagonal supports between the vertical and transverse structures of the terminals. The improved terminal block can be subjected to an external force of 5KN horizontally, and the terminal shape is within the safe range. It can ensure the safety and stability of the main transformer bushing terminal block.
Journal Article
Unveiling the additive-assisted oriented growth of perovskite crystallite for high performance light-emitting diodes
Solution-processed metal halide perovskites have been recognized as one of the most promising semiconductors, with applications in light-emitting diodes (LEDs), solar cells and lasers. Various additives have been widely used in perovskite precursor solutions, aiming to improve the formed perovskite film quality through passivating defects and controlling the crystallinity. The additive’s role of defect passivation has been intensively investigated, while a deep understanding of how additives influence the crystallization process of perovskites is lacking. Here, we reveal a general additive-assisted crystal formation pathway for FAPbI
3
perovskite with vertical orientation, by tracking the chemical interaction in the precursor solution and crystallographic evolution during the film formation process. The resulting understanding motivates us to use a new additive with multi-functional groups, 2-(2-(2-Aminoethoxy)ethoxy)acetic acid, which can facilitate the orientated growth of perovskite and passivate defects, leading to perovskite layer with high crystallinity and low defect density and thereby record-high performance NIR perovskite LEDs (~800 nm emission peak, a peak external quantum efficiency of 22.2% with enhanced stability).
Additives have been widely used for passivating defects in perovskite semiconductors, yet the role of additive and their interaction is not clear. Here, the authors reveal an additive-assisted crystal formation in FAPbI
3
perovskite by tracking the chemical interaction in the precursor solution and crystallographic evolution using multi-functional additives.
Journal Article
Modelling Resonant Depolarisation
2025
For the FCC-ee collider, it is planned to regularly (in 15 minute intervals) measure the average beam energy of the circulating electron and positron beams with a relative precision of 10 −6 or better, using the method of resonant depolarisation with pre-polarised pilot bunches. In this article, we study basic systematic effects and ultimate uncertainties that may arise in this kind of measurement. To do so, we carry out simulations for a simple model representing an ideal situation, where an ensemble of particles with energy spread is subjected to synchrotron oscillations and to perfect spin motion. We assume an initial spin orientation in the vertical direction for all particles. The behavior of the spin is explored as an exciter frequency is swept slowly or rapidly, and in either direction, through the spin resonance.
Journal Article
Biomimetic and biodegradable separator with high modulus and large ionic conductivity enables dendrite-free zinc-ion batteries
2025
The advancement of aqueous zinc-based batteries is greatly restricted by zinc dendrites. One potential solution to this challenge lies in the employment of high-modulus separators. However, achieving both high modulus and large ionic conductivity in a single separator remains a formidable task. Inspired by the wood architecture, this study breaks this trade-off by designing an anisotropic and biodegradable separator. This design significantly improves the modulus along the oriented direction while simultaneously facilitating fast Zn
2+
ion transport through aligned vertical channels. Additionally, this configuration resolves the contradiction between low separator thickness and good dendrite-inhibition capability. These benefits are supported by finite element simulations and comprehensive experimental validation, which also underscore the critical role of modulus enhancement for separators. By employing the anisotropic separator, a prolonged life span is realized for Zn||Zn cells, along with improved cyclability in full batteries. This work presents a strategy for separator modification towards dendrite-free metal batteries.
The separator plays a crucial role in mitigating dendrites and side reactions in aqueous zinc-ion batteries. Here, authors design an anisotropic separator with high modulus and large ionic conductivity to break the trade-off between low separator thickness and good dendrite-inhibition ability.
Journal Article
Origin of vertical orientation in two-dimensional metal halide perovskites and its effect on photovoltaic performance
by
Shiu, Michelle
,
Lee, Seung-Hun
,
Foley, Benjamin J.
in
639/301/299/946
,
639/925/357/1018
,
Charge transport
2018
Thin films based on two-dimensional metal halide perovskites have achieved exceptional performance and stability in numerous optoelectronic device applications. Simple solution processing of the 2D perovskite provides opportunities for manufacturing devices at drastically lower cost compared to current commercial technologies. A key to high device performance is to align the 2D perovskite layers, during the solution processing, vertical to the electrodes to achieve efficient charge transport. However, it is yet to be understood how the counter-intuitive vertical orientations of 2D perovskite layers on substrates can be obtained. Here we report a formation mechanism of such vertically orientated 2D perovskite in which the nucleation and growth arise from the liquid–air interface. As a consequence, choice of substrates can be liberal from polymers to metal oxides depending on targeted application. We also demonstrate control over the degree of preferential orientation of the 2D perovskite layers and its drastic impact on device performance.
It is desirable to align the two-dimensional perovskite layers vertical to the electrodes to maximize device performance but the formation mechanism is unclear. Here Chen et al. reveal that the film formation starts at the liquid-air interface and is thus independent of the choice of substrates.
Journal Article
Hysteresis moment precision compensation of spindle system in vertical composite machining machine tool
2024
To effectively improve the precision compensation and rigidity, according to the structural characteristics of vertical composite machining machine tools, the hysteresis moment precision compensation method was proposed. By optimizing the constrained position, the precision of non-structural geometric changes was effectively compensated. The hysteresis moment precision compensation method proposed in this paper can be well adapted to the micron precision compensation design of machine tools.
Journal Article
Enhanced antibacterial activity through the controlled alignment of graphene oxide nanosheets
by
Elimelech, Menachem
,
Osuji, Chinedum O.
,
Lu, Xinglin
in
Alignment
,
Antibacterial activity
,
Antioxidants
2017
The cytotoxicity of 2D graphene-based nanomaterials (GBNs) is highly important for engineered applications and environmental health. However, the isotropic orientation of GBNs, most notably graphene oxide (GO), in previous experimental studies obscured the interpretation of cytotoxic contributions of nanosheet edges. Here, we investigate the orientation-dependent interaction of GBNs with bacteria using GO composite films. To produce the films, GO nanosheets are aligned in a magnetic field, immobilized by crosslinking of the surrounding matrix, and exposed on the surface through oxidative etching. Characterization by small-angle X-ray scattering and atomic force microscopy confirms that GO nanosheets align progressively well with increasing magnetic field strength and that the alignment is effectively preserved by crosslinking. When contacted with the model bacterium Escherichia coli, GO nanosheets with vertical orientation exhibit enhanced antibacterial activity compared with random and horizontal orientations. Further characterization is performed to explain the enhanced antibacterial activity of the film with vertically aligned GO. Using phospholipid vesicles as a model system, we observe that GO nanosheets induce physical disruption of the lipid bilayer. Additionally, we find substantial GO-induced oxidation of glutathione, a model intracellular antioxidant, paired with limited generation of reactive oxygen species, suggesting that oxidation occurs through a direct electrontransfer mechanism. These physical and chemical mechanisms both require nanosheet penetration of the cell membrane, suggesting that the enhanced antibacterial activity of the film with vertically aligned GO stems from an increased density of edges with a preferential orientation for membrane disruption. The importance of nanosheet penetration for cytotoxicity has direct implications for the design of engineering surfaces using GBNs.
Journal Article
Resolving Three-Dimensional Surface Motion with InSAR: Constraints from Multi-Geometry Data Fusion
by
Garthwaite, Matthew C.
,
Fuhrmann, Thomas
in
Anthropogenic factors
,
Computer simulation
,
crustal deformation
2019
Interferometric synthetic aperture radar (InSAR) technology has been widely applied to measure Earth surface motions related to natural and anthropogenic crustal deformation phenomena. With the widespread uptake of data captured by the European Space Agency’s Sentinel-1 mission and other recently launched or planned space-borne SAR missions, the usage of the InSAR technique to detect and monitor Earth surface displacements will increase even more in the coming years. However, InSAR can only measure a one-dimensional motion along the radar line of sight (LOS), which makes interpretation and communication of InSAR measurements challenging, and can add ambiguity to the modelling process. Within this paper, we investigate the implications of the InSAR LOS geometry using simulated and observed deformation phenomena and describe a methodology for multi-geometry data fusion of LOS InSAR measurements from many viewing geometries. We find that projecting LOS measurements to the vertical direction using the incidence angle of the satellite sensor (and implicitly assuming no horizontal motions are present) may result in large errors depending on the magnitude of horizontal motion and on the steepness of the incidence angle. We quantify these errors as the maximum expected error from simulated LOS observations based on a Mogi deformation model. However, we recommend to use LOS observations from several image geometries wherever data are available, in order to solve for vertical and E–W oriented horizontal motion. For an anthropogenic deformation phenomenon observed in seven independent InSAR analyses of Envisat SAR data from the Sydney region, Australia, we find that the strong horizontal motion present could lead to misinterpretation of the actual motion direction when projecting LOS measurements to vertical (uplift instead of subsidence). In this example, the difference between multi-geometry data fusion and vertical projection of LOS measurements (at an incidence angle of 33.8°) reach up to 67% of the maximum vertical displacement rate. Furthermore, the position of maximum vertical motion is displaced horizontally by several hundred metres when the LOS measurements are projected.
Journal Article
Investigation of phase and temperature perturbations induced by a candle using Hilbert optics methods
2022
The method of multiwave RGB-optical Hilbert diagnostics of the phase and temperature spatial structure of the flame (in an air flow heated by a candle flame) at a fixed moment of time is discussed. The object of study satisfies the model of axial symmetry of the torch associated with the vertical orientation of the candle. The reliability of the received results is confirmed by comparing the reconstructed radial temperature by experimental hilbertogram with data measured by a thermocouple. The flickering effect of the flame was not taken into account in the work, this is the subject of further research.
Journal Article
A Rotation-Invariance Face Detector Based on RetinaNet
by
Yan, Junwei
,
Xiong, Yuyang
,
Yang, Jun
in
Artificial neural networks
,
Detectors
,
Face recognition
2023
The use of deep convolutional neural networks has greatly improved the performance of general face detection. For detecting rotated faces, the mainstream approach is to use multi-stage detectors to gradually adjust the rotated face to a vertical orientation for detection, which increases the complexity of training as multiple networks are involved. In this study, we propose a new method for rotation-invariant face detection, which abandons the previously used cascaded architecture with multiple stages and instead uses a single-stage detector to achieve end-to-end detection of face classification, face box regression, and facial landmark regression. Extensive experiments on FDDB in multiple orientations have shown the effectiveness of our method. The results demonstrate that our method achieves good detection performance and the detection accuracy of our method even exceeds that of other rotated face detectors on the front-facing FDDB dataset.
Journal Article