Liu, Xu
Chen, Nan
Xing, Xinxin
Li, Yuxiu
Xiao, Xuechun
Wang, Yude
Djerdj, Igor
ZnO nanoparticles with high crystallinity and several nanometers in size were synthesized by a low-temperature solvothermal route from zinc acetate dihydrate (Zn(CH3COO)2·2H2O), potassium hydroxide (KOH) and methanol (CH3OH). The structural and the morphological characterizations of the ZnO nanoparticles were performed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and N2-sorption isotherms. The obtained nanoparticles are highly crystalline wurtzite-type ZnO with a uniform near-spherical shape and an average particle size estimated to be 8.4 ± 1.3 nm. Such a small particle size and slight agglomeration are attributed to the use of methanol, which acts as both a solvent and an inhibitor of growth and agglomeration. The as-synthesized ZnO nanoparticles were directly used as a gas sensing material toward n-butanol gas. Such a designed sensor device exhibits several advantages such as a high and fast response, short recovery time, and good stability toward n-butanol gas. At the optimal operating temperature (320 °C), its gas response toward 500 ppm n-butanol is 805 and the response and recovery times are 22 and 6 seconds, respectively.
Highlights • A regional based tool path generation method is proposed and tested. • A tensor is derived to evaluate machining strip width using ball end mill. • A surface division method is presented based on machining strip width tensor field. Abstract Due to the complexity of geometry, the feed direction with maximal machining strip width usually varies among different regions over a freeform surface or a shell of surfaces. However, in most traditional tool path generation methods, the surface is treated as one machining region thus only local optimisation might be achieved. This paper presents a new region-based tool path generation method. To achieve the full effect of the optimal feed direction, a surface is divided into several sub-surface regions before tool path computation. Different from the scalar field representation of the machining strip width, a rank-two tensor field is derived to evaluate the machining strip width using ball end mill. The continuous tensor field is able to represent the machining strip widths in all feed directions at each cutter contact point, except at the boundaries between sub-regions. Critical points where the tensor field is discontinuous are defined and classified. By applying critical points in the freeform surface as the start for constructing inside boundaries, the surface could be accurately divided to such that each region contain continuous distribution of feed directions with maximal machining strip width. As a result, tool paths are generated in each sub-surface separately to achieve better machining efficiency. The proposed method was tested using two freeform surfaces and the comparison to several leading existing tool path generation methods is also provided.
A display system for 3D light field generation is presented. The display system comprises a photonic circuit comprising a plurality of light emitting units, wherein each light emitting unit comprises a light intensity modulator, and the display system also comprises a phased liquid crystal array adapted to control the exiting optical angle of light for emission angle steering. The operations of light intensity modulators and the phased liquid crystal array are synchronized when reconstructing a light field of a virtual 3D object viewed by a user's eye.
A method and system for proactively dropping video frames are disclosed. The method includes: recording, by a computer, a video frame capture timestamp for a video frame that is captured at a first device; associating, by the computer, the video frame capture timestamp to the video frame that is captured; comparing, by the computer, the video frame capture timestamp with a video frame target timestamp for the video frame; and based on the comparing, if a time difference between the video frame capture timestamp and the video frame target timestamp is outside of a predetermined range of time values, then dropping, by the computer, the video frame.
PDZ (PSD-95/DIg/ZO-1) domains are protein-protein interaction modules often regulated by ligand phosphorylation. Here, we investigated the specificity, structure, and dynamics of Tiam1 PDZ domain/ligand interactions. We show that the PDZ domain specifically binds syndecan1 (SDC1), phosphorylated SDC1 (pSDC1), and SDC3 but not other syndecan isoforms. The crystal structure of the PDZ/SDC1 complex indicates that syndecan affinity is derived from amino acids beyond the four C-terminal residues. Remarkably, the crystal structure of the PDZ/pSDC1 complex reveals a binding pocket that accommodates the phosphoryl group. Methyl relaxation experiments of PDZ/SCD1 and PDZ/pSDC1 complexes reveal that PDZ-phosphoryl interactions dampen dynamic motions in a distal region of the PDZ domain by decoupling them from the ligand-binding site. Our data are consistent with a selection model by which specificity and phosphorylation regulate PDZ/syndecan interactions and signaling events. Importantly, our relaxation data demonstrate that PDZ/phospho-ligand interactions regulate protein dynamics and their coupling to distal sites.
A three-dimensional (3D) scene of fibre-to-chip coupling is reconstructed from three captured 2D graphics in which coordinate system transformation and distortionless segmentation image fusion algorithm are presented to visually guide precise alignment and nanopositioning procedures based on the established single lens photometric machine vision system. As an instance, the 3D scene on wedge-shaped fibre (WSF) coupling with indium phosphide (InP) photonic integrated circuit (PIC) chip is demonstrated, where the wedged angle is calculated to be 46.5°, differing from the nominal value of 45° with the error <;3.5%, and for the longitudinal displacement, the computation of 94 μm has the error within 7% compared with the measurement of 88 μm. Under the guidance of 3D scene reconstruction on WSF-InP PIC, the coupling efficiency is 2 dB higher than that without such stereoscopic image.