A new strategy for the preparation of polylactic acid composites with UV resistance, light conversion, and antibacterial properties.

A novel rare earth complex, Eu(IAA)(phen) (EuIP), was synthesized by solution-based synthesis method. Then, EuIP and polylactic acid (PLA) were melt-blended at 190 °C to obtain a multifunctional PLA/EuIP composite. The incorporation of EuIP provided PLA/EuIP composites with good light conversion ability.

Effect of a Self-Assembled Nucleating Agent on the Crystallization Behavior and Spherulitic Morphology of Poly(lactic acid).

Herein, decanedioic acid dibenzoylhydrazide (DDBH) was used as a nucleating agent to improve the crystallization of poly(lactic acid) (PLA). The formation of DDBH assemblies in PLA melts at different concentrations was systematically investigated. The DDBH (0.

Adaptive focal lengths in white light focusing Fresnel lenses enabled by reflective-type and phase-only spatial light modulator.

Fresnel zone plates (FZPs) are widely used in integrated optical systems to meet new cutting-edge demands for photonic integration and device miniaturizing. However, their use in applications of cross-scale fabrication still faces several obstacles, such as low efficiency, fixed focal length, single wavelength, large size, and complicated fabrication. Here, we first examine a novel adaptive focal length in white light focusing by using reflective-type and phase-only spatial light modulator (RLC-SLM) based on a liquid crystal on silicon.

Fabrication of azimuthally/radially symmetric liquid crystal plates using two-step photoalignments.

Fabrication of azimuthally/radially symmetric liquid crystal plates (A/RSLCPs) using two-step photoalignments with the two dichroic dyes methyl red (MR) and brilliant yellow (BY) is demonstrated. BY molecules coated onto a substrate and MR molecules doped in LCs in a cell can azimuthally and radially align LCs by illuminating radially and azimuthally symmetric polarized light with specific wavelengths, respectively. In contrast to the previous fabrication methods, the fabrication method proposed here can prevent the contamination/damage of photoalignment films on substrates.

Fluorine- and Acid-Free Strategy toward Scalable Fabrication of Two-Dimensional MXenes for Sodium-Ion Batteries.

MXenes are emerging 2D materials that have gained great attention because of their unique physical-chemical properties. However, the wide application of MXenes is prohibited by their high cost and environmentally harmful synthesis process. Here a fluoride- and acid-free physical vacuum distillation strategy is proposed to directly synthesize a series of MXenes.

Hiding private information in private information protection liquid crystal displays using periodical waveplates and pixel quaternity.

A method to hide private information (PI) in private information protection liquid crystal displays (PIPLCDs) using periodical waveplates and pixel quaternity is reported in this study. The PIPLCD structure and its operation mechanism are conceptually elucidated. Users employing wide-view broadband circular polarizers (WVBCPs) can see PI hidden in images displayed on the PIPLCDs in PIP mode.

Identification and evaluation of soil moisture flash drought by a nonstationary framework considering climate and land cover changes.

Soil moisture flash drought can cause extensive damage to agriculture, ecosystems, and economies due to its sudden onset. Previous research identified soil moisture flash drought using stationary methods, in which, stationary probability distributions were employed to derive cumulative percentages (CPs) of given soil moisture values, and then based on the CPs sequence, the run theory was used to identify soil moisture flash drought events. However, because changes in climate or land cover can induce significant variations in the underlying probability distributions of soil moisture, the method's usual assumption of stationarity should be questioned.

Highly Reversible Zn Metal Anodes Enabled by Freestanding, Lightweight, and Zincophilic MXene/Nanoporous Oxide Heterostructure Engineered Separator for Flexible Zn-MnO Batteries.

Aqueous zinc (Zn)-ion batteries are regarded as promising candidates for large-scale energy storage systems because of their high safety, low cost, and environmental benignity. However, the dendrite issue of Zn anode hinders their practical application. Herein, a freestanding, lightweight, and zincophilic MXene/nanoporous oxide heterostructure engineered separator is designed to stabilize a Zn metal anode.

One-Step, Vacuum-Assisted Construction of Micrometer-Sized Nanoporous Silicon Confined by Uniform Two-Dimensional N-Doped Carbon toward Advanced Li Ion and MXene-Based Li Metal Batteries.

With the advantages of a high theoretical capacity, proper working voltage, and abundant reserves, silicon (Si) is regarded as a promising anode for lithium-ion batteries. However, huge volume expansion and low electronic conductivity impede the commercialization of Si anodes. We devised a one-step, vacuum-assisted reactive carbon coating technique to controllably produce micrometer-sized nanoporous silicon confined by homogeneous N-doped carbon nanosheet frameworks (NPSi@NCNFs), achieved by the solid state reaction of a commercial bulk precursor and the subsequent evaporation of byproducts.

Rational Design of Sulfur-Doped Three-Dimensional TiCT MXene/ZnS Heterostructure as Multifunctional Protective Layer for Dendrite-Free Zinc-Ion Batteries.

Owing to its high theoretical capacity, appropriate working potential, abundant resource, intrinsic safety, and low cost, zinc (Zn) metal is regarded as one of the most promising anode candidates for aqueous batteries. However, the hazards caused by dendrite growth and side reactions impede its practical applications. Herein, to solve these problems, a protective heterogeneous layer composed of electronic conductive sulfur-doped three-dimensional (3D) MXene and ionic conductive ZnS on Zn anode is designed and constructed.

Perfluorobutane contrast-enhanced ultrasonography for the diagnosis of HCC: a systematic review and meta-analysis.

Objectives: Perfluorobutane ultrasound contrast agent as a new type of contrast agent has a good performance in the diagnosis of hepatocellular carcinoma (HCC). This study aim to evaluate the accuracy and reliability of Perfluorobutane contrast-enhanced ultrasonography (P-CEUS) in the diagnosis of HCC with a systematic review and meta-analysis.

Methods: Web of Science, EMBASE, Cochrane, Clinical Key, Wan Fang, CBM and CNKI databases were systematically searched and checked for studies using P-CEUS in HCC, from 2007 to 2020.

Multiple-Color Reflectors Using Bichiral Liquid Crystal Polymer Films and Their Applications in Liquid Crystal Displays.

Multiple-color reflectors using bichiral liquid crystal polymer films (BLCPFs) are investigated. The BLCPFs consist of alternate layers of two different single-pitch cholesteric liquid crystal (CLC) layers, named CLC#A and CLC#B. The thickness of each CLC layer equals its single pitch length.

High-Contrast and Scattering-Type Transflective Liquid Crystal Displays Based on Polymer-Network Liquid Crystals.

The methods to enhance contrast ratios (CRs) in scattering-type transflective liquid crystal displays (ST-TRLCDs) based on polymer-network liquid crystal (PNLC) cells are investigated. Two configurations of ST-TRLCDs are studied and are compared with the common ST-TRLCDs. According to the comparisons, CRs are effectively enhanced by assembling a linear polarizer at the suitable position to achieve better dark states in the transmissive and reflective modes of the reported ST-TRLCDs with the optimized configuration, and its main trade-off is the loss of brightness in the reflective modes.

Low-Threshold-Voltage and Electrically Switchable Polarization-Selective Scattering Mode Liquid Crystal Light Shutters.

Low-threshold-voltage (V) and electrically switchable, polarization-selective scattering mode light shutters (PSMLSs) using polymer-dispersed liquid crystals (PDLCs) are demonstrated in this work. The optimized weight ratio of the nematic liquid crystals (LCs) to the adopted monomer (NBA107, Norland Optics) in the low-V PDLCs based on NBA107 is 7:3, [7:3]-PDLCs. The properties of the low-V PDLCs, such as light-scattering performance, initial transmission, V, and droplet size were investigated.

Achromatic linear polarization rotators by tandem twisted nematic liquid crystal cells.

An achromatic linear polarization rotator based on a tandem-2ϕ-twisted nematic liquid crystal cell (tandem-2ϕ-TNLC cell, where 2ϕ represents the total twisted angle) is theoretically analyzed and experimentally demonstrated. The tandem-2ϕ-TNLC cell comprises two conventional ϕ-TNLC cells with the required arrangement that the LC director close to the last layer of the first ϕ-TNLC cell should be perpendicular to that close to the first layer of the second ϕ-TNLC cell. With such a simple combination, the TNLC performances are considerably improved.

General theory of asymmetrical polarization-dependent optics in functional material-doped 90° twisted nematic liquid crystals.

General theory, which can completely describe the asymmetrical optics in a functional material (FM)-doped 90° twisted nematic liquid crystals (TNLCs), is proposed using Cayley-Hamilton theorem and Jones calculus. The FMs, whose shape and size are similar to those of the adopted NLCs, can be aligned along the long axes of the NLCs. The FMs discussed herein are dichroic dye (DD) and polymer.

Optically Controllable Linear-Polarization Rotator Using Chiral-Azobenzene-Doped Liquid Crystals.

A linear-polarization rotator based on the optically tunable pitch of chiral-azobenzene-doped liquid crystals (CAdLCs) has been investigated. It is shown that the orientation of linearly polarized (LP) light can be optically tuned using CAdLCs and that the transmitted light possesses a good degree of linear polarization (DoLP). Experimental and simulation (4 × 4 Berreman matrix) results show that the rotation angle is dependent on the pitch as well as the number of turns of the cholesteric LC helix.

Asymmetrical polarization-dependent scattering and reflection in a sole cell of polymer network-90° twisted nematic liquid crystals.

The anisotropically intrinsic scattering and reflection of a sole cell of polymer network-90° twisted nematic liquid crystals (PN-90° TNLCs) without any polarizer are proposed. Light with specifically linear polarizations, incident from one direction, can penetrate the PN-90° TNLCs with applied voltage. The polarization direction of the output beam will be rotated 90°.

Expanding color gamut of reflective liquid crystal displays from filtering undesirable wavelengths of a light source by an embedded etalon.

This work demonstrates a method to reduce the intensity of the undesirable wavelengths of blue (B-) and green (G-) ambient lights to expand the color gamut of reflective liquid crystal displays (LCDs) by an embedded etalon. The built-in reflector of the reflective LCDs is replaced by the blue-green overlapping wavelengths filtering etalon, which is used to reduce the intensity of undesirable B- and G-primaries, thereby decreasing the color cross talk of B- and G-color filters. After etalon adoption, the color gamut can be expanded from 105.

Optical simulation of single-cell-gap transflective liquid crystal displays based on surface anchoring energy of periodical nano-grooved structures.

The single-cell-gap transflective liquid crystal display (TR-LCD) based on periodic distribution of surface anchoring energy (SAE) of periodical nano-grooved structures is reported in this study. Different SAEs of planar-aligned nematic LC cells are associated with the threshold and operation voltages of the adopted LCs. Thus, according to the transmittance versus applied voltage curves, the regions with strong and weak SAEs in LC cells can be the transmission and reflection regions of a TR-LCD, respectively.

Electro-opto-thermal addressing bistable and re-addressable display device based on gelator-doped liquid crystals in a poly(N-vinylcarbazole) film-coated liquid crystal cell.

This paper reports an electro-opto-thermal addressing bistable and re-addressable display device based on gelator-doped liquid crystals (LCs) in a poly(N-vinylcarbazole) film-coated LC cell. The bistability and re-addressability of the devices were achieved through the formation of a rubbery LC/gel mixture at room temperature. The desired patterns were addressed, erased, and re-addressed by controlling the temperature, applied voltage, and UV light illumination.

Electrically Switchable and Permanently Stable Light Scattering Modes by Dynamic Fingerprint Chiral Textures.

Negative dielectric nematic liquid crystals (LCs) doped with two azobenzene materials provide electrically switchable and permanently stable scattering mode light modulators based on dynamic fingerprint chiral textures (DFCT) with inhomogeneously helical axes. These light modulators can be switched between transparent (stable large domains of DFCT) states and scattering (stable small domains of DFCT) states by applying electric fields with different frequencies. The generation of DFCT results from the long flexible side chains of the doped chiral dopant.

Direct optical switching of bistable cholesteric textures in chiral azobenzene-doped liquid crystals.

The direct optical switching of bistable cholesteric textures (i.e., planar and focal conic textures) in chiral azobenzene-doped liquid crystals (LCs) is demonstrated.

Dual liquid crystal alignment configuration based on nanoparticle-doped polymer films.

This paper proposes an approach for producing dual liquid crystal (LC) alignment configuration based on nanoparticle-doped polymer films. Experimental results indicate that illuminating a nanoparticle-doped pre-polymer film, coated onto a substrate with a homogeneous alignment layer, with unpolarized UV light through a photomask causes the polymerization of pre-polymer, ultimately generating homogeneous and vertical alignment layers in unpolymerized and polymerized regions, respectively. The dual LC alignment configuration of the homogeneous (vertical) and hybrid alignments can be achieved by combining the treated substrate with another substrate that has a homogeneous (vertical) alignment layer.

Polarization rotators fabricated by thermally-switched liquid crystal alignments based on rubbed poly(N-vinyl carbazole) films.

This paper demonstrates the thermally-switched liquid crystal (LC) alignments based on a rubbed poly(N-vinyl carbazole) (PVK) film, and their application for polarization rotators. The mechanically rubbed PVK layer can induce a planar alignment of LCs with their director axis perpendicular to the direction of rubbing. This direction can be switched toward the rubbing direction by thermal treatment.