Abstract
Light projection displays play an increasingly important role in our modern life. Core projection systems including liquid crystal displays and digital micromirror devices can impose spatial ...light modulation and actively shape light waves. Recently, the advent of metasurfaces has revolutionized design concepts in nanophotonics, enabling a new family of optical elements with exceptional degrees of freedom. Here, we demonstrate a light projection display technology based on optical metasurfaces, called digital metasurface device (DMSD). Each metasurface pixel in a DMSD is electrically reconfigurable with well-controlled programmability and addressability. The DMSD can not only continuously modulate the intensity of light with high contrast, but also shape the wavefront of light generated by each metasurface pixel and dynamically switch between arbitrary holographic patterns. Our approach will pave an avenue towards the development of customized light projection devices. It will also drive the field of dynamic optical metasurfaces with fresh momentum and inspiring concepts.
OVATE gene was first identified as a key regulator of fruit shape in tomato. OVATE family proteins (OFPs) are characterized as plant-specific transcription factors and conserved in Arabidopsis, ...tomato, and rice. Roles of OFPs involved in plant development and growth are largely unknown. Brassinosteroids (BRs) are a class of steroid hormones involved in diverse biological functions. OsGKS2 plays a critical role in BR signaling by phosphorylating downstream components such as OsBZR1 and DLT. Here we report in rice that OsOFP8 plays a positive role in BR signaling pathway. BL treatment induced the expression of OsOFP8 and led to enhanced accumulation of OsOFP8 protein. The gain-of-function mutant Osofp8 and OsOFP8 overexpression lines showed enhanced lamina joint inclination, whereas OsOFP8 RNAi transgenic lines showed more upright leaf phenotype, which suggest that OsOFP8 is involved in BR responses. Further analyses indicated that OsGSK2 interacts with and phosphorylates OsOFP8. BRZ treatment resulted in the cytoplasmic distribution of OsOFP8, and bikinin treatment reduced the cytoplasmic accumulation of OsOFP8. Phosphorylation of OsOFP8 by OsGSK2 is needed for its nuclear export. The phospphorylated OsOFP8 shuttles to the cytoplasm and is targeted for proteasomal degradation. These results indicate that OsOFP8 is a substrate of OsGSK2 and the function of OsOFP8 in plant growth and development is at least partly through the BR signaling pathway.
YABBY genes encode seed plant-specific transcription factors that play pivotal roles in diverse aspects of leaf, shoot, and flower development. Members of the YABBY gene family are primarily ...expressed in lateral organs in a polar manner and function to specify abaxial cell fate in dicotyledons, but this polar expression is not conserved in monocotyledons. The function of YABBY genes is therefore not well understood in monocotyledons. Here we show that overexpression of the rice (Oryza sativa L.) YABBY4 gene (OsYABBY4) leads to a semi-dwarf phenotype, abnormal development in the uppermost internode, an increased number of floral organs, and insensitivity to gibberellin (GA) treatment. We report on an important role for OsYABBY4 in negative control of the expression of a GA biosynthetic gene by binding to the promoter region of the gibberellin 20-oxidase 2 gene (GA20ox2), which is a direct target of SLR1 (the sole DELLA protein negatively controlling GA responses in rice). OsYABBY4 also suppresses the expression level of SLR1 and interacts with SLR1 protein. The interaction inhibits GA-dependent degradation of SLR1 and therefore leads to GA insensitivity. These data together suggest that OsYABBY4 serves as a DNA-binding intermediate protein for SLR1 and is associated with the GA signaling pathway regulating gene expression during plant growth and development.
The ball screw pair is a precision drive component that converts rotary motion into linear motion. In practical applications, because the feed system usually has rotational torque and geometric ...errors, it may increase the contact load of the ball screw pair and reduce the fatigue life. In order to study the influence of different loads and geometric errors on the maximum contact load and fatigue life of ball screw pairs, the following research work was carried out. Firstly, based on the composite load and rotational torque, the ball load distribution model is established, and the accuracy of the model is verified by finite element modeling analysis. Then, the influence of different composite loads, rotation times and geometric errors (including ball size error, lead error and raceway tooth profile error) on the ball load distribution is analyzed. Finally, the influence of compound load, rotating torque and geometric error on the fatigue life of ball screw pairs is studied. The results show that the rotational torque and lead error have a great influence on the load distribution and fatigue life of the ball, and the influence of lead error on load distribution is greater than that of dimension error and tooth profile error. The fatigue life of the ball screw pair with non-uniform load distribution is shorter than that of the ball screw pair with uniform load distribution.
Plant growth and development are highly coordinated by hormones, including brassinosteroid (BR) and gibberellin (GA). Although much progress has been made in understanding the fundamental signaling ...transduction in BR and GA, their relationship remains elusive in rice.
Here, we show that BR suppresses the level of OsmiR159d, which cleaves the target OsGAMYBL2 gene. The OsmiR159d-OsGAMYBL2 pair functions as an early BR-responsive module regulating the expression of BU1, a BR-regulated gene involved in BR signaling, and CPS1 and GA3ox2, two genes in GA biosynthesis, by binding to the promoters of these genes.
Furthermore, OsGSK2, a key negative player in BR signaling, interacts with OsGAMYBL2 and prevents it from being degraded under 24-epibrassinolide treatment, whereas SLR1, a rice DELLA protein negatively regulating GA signaling, interacts with OsGAMYBL2 and prevents OsGAMYBL2 from binding to the target gene promoter. GA signaling induces degradation of OsGAMYBL2 and, consequently, enhances BR signaling.
These results demonstrate that a BR-responsive module acts as a common component functioning in both BR and GA pathways, which connects BR signaling and GA biosynthesis, and thus coordinates the regulation of BR and GA in plant growth and development.
This paper introduces a three-dimensional (3D) point cloud data obtained method based on a laser line scanner and data processing technology via a PCL open project. This paper also provides a ...systematical analysis of the error types of laser line scanner and common error reducing solutions and calibration of the laser line scanner. The laser line scanner is combined with a precision motorized stage to obtain the 3D information of a measurand, and the format of point cloud data is converted via the set of
,
, and
coordinates. The original signal is processed according to the noise signal types of the raw point cloud data. This paper introduced a denoise process step by step combining various segmentation methods and a more optimized three-dimensional data model is obtained. A novel method for industry inspection based on the numerous point cloud for the dimensions evaluation via feature extraction and the deviation of complex surface between scanned point cloud and designed point cloud via registration algorithm is proposed. Measurement results demonstrate the good performance of the proposed methods. An obtained point cloud precision of ±10 μm is achieved, and the precision of dimension evaluation is less than ±40 μm. The results shown in the research demonstrated that the proposed method allows a higher precision and relative efficiency in measurement of dimensions and deviation of complex surfaces in industrial inspection.
Based on the stretched coordinate perfectly matched layer (SC-PML) formulations and the auxiliary differential equation (ADE) method, an efficient and unsplit-field implementation of the higher-order ...PML scheme with more than one pole is proposed to truncate the finite-difference time-domain (FDTD) lattices. The higher-order PML has the advantages of both the conventional PML and the complex frequency shifted PML (CFS-PML) in terms of absorbing performances. The proposed algorithm is validated through two numerical tests carried out in three dimensional and two dimensional domains. It is shown in the numerical simulations that the proposed PML formulations with the higher-order scheme are efficient in terms of attenuating both the low-frequency propagating waves and evanescent waves and reducing late-time reflections, and also hold much better absorbing performances than the conventional SC-PML and the convolutional PML (CPML) with the CFS scheme.
An unusual oxidative coupling reaction of isocyanide and toluene derivatives using tetrabutylammonium iodide (TBAI) as a catalyst is disclosed. The experimental results and mechanistic study show ...that the isocyano group acts formally as an N1 synthon during the transformation, thus expanding the reactivity profile of isocyanide.
Seven races of Striga gesnerioides parasitic on cowpea, a major food and forage legume in sub-Saharan Africa, have been identified. Race-specific resistance of cowpea to Striga involves a coiled-coil ...nucleotide binding site leucine-rich repeat domain resistance protein encoded by the RSG3-301 gene. Knockdown of RSG3-301 expression by virus-induced gene silencing in the multirace-resistant cowpea cultivar B301 results in the failure of RSG3-301-silenced plants to mount a hypersensitive response and promotes parasite necrosis when challenged with Striga race SG3, whereas the resistance response to races SG2 and SG5 is unaltered. Our findings indicate that a gene-for-gene resistance mechanism is operating in these unique plant-plant associations.
Metasurfaces, which are capable of generating structure and wavelength dependent phase shift, have emerged as promising means for controlling the wavefront of electromagnetic waves. Finding new ways ...to realize broadband frequency response as well as maintaining high conversion efficiency still requires research efforts. For the design of plasmonic metasurfaces, graphene represents an attractive alternative to metals due to its strong field confinement and versatile tunability. Here, a novel metasurface based on graphene is proposed to control the wavefront of light. Dynamically tunable anomalous refraction composed of periodically patterned graphene nanocrosses for circularly polarized waves is achieved in the infrared regime. Broadband properties of anomalous refraction are demonstrated by investigating different frequencies and incident angles. Moreover, the anomalous conversion efficiency can be dynamically tuned and remain as high in a broadband frequency range by varying the Fermi energy without reoptimizing the nanostructures. This work may offer a further step in the development of a tunable wavefront controlling device.
A novel graphene metasurface composed of periodically patterned graphene nanocrosses allows dynamic tuning of the anomalous refraction for circularly polarized waves in the IR regime. Broadband properties of anomalous refraction are demonstrated by investigating different frequencies and incident angles. The anomalous conversion efficiency can be dynamically tuned and remain high in a broadband frequency range by varying the Fermi energy without reoptimizing the nanostructures.
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