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- 2018
- 3D display
- holographic display
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- volumetric display
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- Shanghai Jiao Tong University
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Ku-Band Liquid-Crystal-Based Frequency Reconfigurable Comb SIW Slot Leaky-Wave Antenna
摘要： In this paper, based on liquid crystal anisotropy characteristics, a kind of frequency reconfigurable comb substrate integrate waveguide slot leaky-wave antenna use liquid-crystal-based is proposed at Ku band. It adopt comb shape and defected ground structure to compose comb SIW’s top and bottom. The slots are etched at top and bottom surface. The resonant point of propose antenna move from 15.85GHz to 14.37GHz, the tunable range is 1.5GHz by changing liquid crystal’s permittivity. Return loss less than -30dB at resonant point and the maximum gain is 8.79dB. The bandwidth of proposed antenna is 1 GHz. All the results show the reconfigurable of proposed antenna is good.
关键词： leaky-wave antenna,reconfigurable,comb substrate integrate waveguide,liquid crystal
更新于2025-09-04 15:30:14
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Modern Purification Methods for Liquid Scintillators Intended for Recording Rare Events
摘要： Chromato-mass-spectrometry and UV/VIS spectroscopy are used to study the composition and properties of linear alkyl benzene (LAB) produced in Russia as the basic solvent for production of low-background liquid scintillators. The efficiency of LAB purification by reducing intrinsic radioactivity (U, Th) via water extraction (with addition of a strong chelate, dimethylaminomethylendiphosphonic acid) and sorption on Al2O3 in silica gel is studied. The purification method for removing potassium from scintillation fluors (PPO, BPO, p-terphenyl) is developed. It is shown that U and Th can be efficiently extracted from NdCl3 water solutions with 0.1 M TOPO solution in pseudocumene.
关键词： NdCl3 water solutions,liquid scintillators,purification methods,sorption,potassium removal,radioactivity,linear alkyl benzene,water extraction
更新于2025-09-04 15:30:14
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Confocal Fluorescence Microscopy and Kinetics of the Cr3+-Chromate Ion Oxidation Equilibria at the Solid Liquid Interface
摘要： Silica-borax pearl samples impregnated with 0.17 and 0.64% Cr3+ were characterized by specific surface area measurements, UV-Vis spectroscopy, energy-dispersive X-ray fluorescence and laser-scanning confocal microscopy. Pearl stability against oxidizing conditions was tested by adding samples to an aqueous hydrogen peroxide solution. The reaction was examined by UV-Vis spectroscopic measurements of the supernatant and laser-scanning confocal microscopy images of the substrate. Overall, hydrogen peroxide-induced Cr3+ to Cr6+ oxidation across the solid-liquid interface promoted solid matrix cleavage pearl degradation and concomitant formation of multiple scattering centers was observed. A dual-detection scheme was employed in the confocal microscopy measurements allowing us to separate scattering and absorptive contributions to the observed signals. The confocal microscopy images indicate that Cr3+ oxidation induced by hydrogen peroxide solutions occurs throughout the entire pearl sample and indicate that oxidation reactions induce leakage of chromate ion into aqueous solutions.
关键词： energy dispersive X-ray fluorescence,confocal fluorescence microscopy,chromium mobility,H2O2 oxidation equilibria,mass transfer phenomena,solid liquid interfaces
更新于2025-09-04 15:30:14
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Geometric stabilisation of topological defects on micro-helices and grooved rods in nematic liquid crystals
摘要： We demonstrate how the geometric shape of a rod in a nematic liquid crystal can stabilise a large number of oppositely charged topological defects. A rod is of the same shape as a sphere, both having genus g = 0, which means that the sum of all topological charges of defects on a rod has to be (cid:2)1 it usually shows only one hyperbolic hedgehog or a Saturn ring defect with negative unit charge. Multiple unit charges can be stabilised either by friction or large length, which screens the pair-interaction of unit charges. Here we show that the curved shape of helical colloids or the grooved surface of a straight rod create energy barriers between neighbouring defects and prevent their annihilation. The experiments also clearly support the Gauss–Bonnet theorem and show that topological defects on helices or grooved rods always appear in an odd number of unit topological charges with a total topological charge of (cid:2)1.
关键词： topological defects,geometric stabilisation,micro-helices,nematic liquid crystals,grooved rods
更新于2025-09-04 15:30:14
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Phase behavior of main-chain liquid crystalline polymer networks synthesized by alkyne–azide cycloaddition chemistry
摘要： Liquid crystalline polymer networks (LCNs) couple polymer chain organization to molecular ordering, the switching of which has been shown to impart stimuli-responsive properties, including actuation and one-way shape memory, to the networks. While LCNs have long been proposed as artificial muscles, recent reports have also suggested potential as dynamic biomaterial substrates. In contrast to many existing LCNs synthesized using hydrophobic spacers, this work investigates networks synthesized using more hydrophilic spacers to promote interaction with water. A challenge with such materials is liquid crystalline phases could be disrupted in hydrated networks. This work thus investigates the impact of polyether spacers and mesogen composition on the phase behavior of LCNs. Main-chain LCNs were synthesized using alkyne–azide cycloaddition ("click" chemistry), where two different mesogens (5yH and 5yMe) and a non-LC monomer (5yTe) were coupled with one of two different polyether spacers, poly(ethylene glycol) and poly(propylene glycol), and a crosslinker. The chemistry led to high gel fraction materials, the workup of which resulted in networks that displayed no difference in cellular toxicity due to leachable components compared to tissue culture plastic control. Calorimetric analysis, dynamic mechanical analysis, and X-ray scattering revealed the LC microstructure and temperature-responsive properties of the networks. The use of low molecular weight polyether spacers was found to prevent their crystallization within the LC network, and adjusting mesogen composition to enhance its LC phase stability allowed the use of spacers with larger molecular weights and pendant groups. Hydrated networks were found to rearrange their structure compared to dry networks, while maintaining their LC phases. Like other crosslinked LC materials, the networks display shape changes (actuation) that are tied to changes in LC ordering. The result is a new synthetic approach for polydomain networks that form stable LC phases that are tailorable using polyether spacers and may enable future application as hydrated, stimuli-responsive materials.
关键词： Liquid crystalline polymer networks,Phase behavior,Alkyne–azide cycloaddition,Stimuli-responsive materials,Polyether spacers
更新于2025-09-04 15:30:14