Mechanochromic and Solvomechanochromic Fluorescent Photonic Crystals for Dual-Mode Modulating Fluorescence and Multilevel Anticounterfeiting.

Fluorescent photonic crystals (FPCs) are ideal candidates for regulating dyes' fluorescence through their unique photonic band gaps (PBGs). However, challenges, including the lack of dynamic regulation of fluorescence, dye release in solvents, and instability, dramatically limit their practical applications. Here, we report mechanochromic and solvomechanochromic rhodamine B (RhB)-based FPCs with dynamic regulation of photoluminescence (PL) by stretching and swelling, brilliant fluorescent and structural colors, and no release of the RhB in solvents. The FPCs with force/solvent-responsive nonclose-packing structures were fabricated by (1) preparing RhB-silica particles by combining click chemistry and cohydrolysis processes and (2) self-assembling these particles in poly(ethylene glycol) phenyl ether acrylate followed by a photopolymerization. Maximal PL inhibition (37%, stretching strain of 6.8%) and enhancement (150%, swelling time of 8 min) were gained when PBGs and their blue edges are precisely adjusted to the PL peak position, respectively. Compared with stretching, PL regulation is more efficient by swelling. These characteristics benefit from the rational design and combination of unique compositions, chemical bonds, nonclosely packed micro/nanostructures, and solvents for swelling. Moreover, these FPCs have been used to encrypt photonic patterns, which display background/strain/angle/UV-dependent color contrasts, showing their potential applications in multilevel anticounterfeiting, optical devices, wireless sensors, etc.

High-Performance 3D Stacked Micro All-Solid-State Thin-Film Lithium-Ion Batteries Based on the Stress-Compensation Effect.

A novel all-solid-state thin-film lithium-ion battery (LIB) is presented to address the trade-off issue between the specific capacity and stabilities in a conventional LIB. Different from the conventional one, this LIB device consists of two same LIB components located at the front and back surfaces of the substrate, respectively. These two LIB components form parallel connection by using the conductive through vias distributed in the substrate. Compared with the conventional one, this LIB device doubles the areal specific capacity. More importantly, due to the stress-compensation effect, this device effectively suppresses the stress induced by its volume changes resulting from the lithiation/delithiation processes and thermal expansion. Consequently, this device shows good cycling and thermal stabilities even when working at an industrial-grade high temperature of 125 °C. To further improve the specific capacity without sacrificing the stabilities, a 3D stacked LIB is successfully realized by using this LIB device as the cell, in which each cell is parallelly connected by using the above-mentioned conductive through vias. This 3D stacked LIB is experimentally demonstrated to obtain high specific capacity (79.9 µAh cm-2 ) and good stabilities (69.3% of retained capacity after 100 cycles at 125 °C) simultaneously.

Bio-Inspired Highly Brilliant Structural Colors and Derived Photonic Superstructures for Information Encryption and Fluorescence Enhancement.

Inspired by the brilliant and tunable structural colors based on the large refractive index contrast (Δn) and non-close-packing structures of chameleon skins, ZnS-silica photonic crystals (PCs) with highly saturated and adjustable colors are fabricated. Due to the large Δn and non-close-packing structure, ZnS-silica PCs show 1) intense reflectance (maximal: 90%), wide photonic bandgaps, and large peak areas, 2.6-7.6, 1.6, and 4.0 times higher than those of silica PCs, respectively; 2) tunable colors by simply adjusting the volume fraction of particles with the same size, more convenient than the conventional way of altering particle sizes; and 3) a relatively low threshold of PC's thickness (57 µm) possessing maximal reflectance compared to that (>200 µm) of the silica PCs. Benefiting from the core-shell structure of the particles, various derived photonic superstructures are fabricated by co-assembling ZnS-silica and silica particles into PCs or by selectively etching silica or ZnS of ZnS-silica/silica and ZnS-silica PCs. A new information encryption technique is developed based on the unique reversible "disorder-order" switch of water-responsive photonic superstructures. Additionally, ZnS-silica PCs are ideal candidates for enhancing fluorescence (approximately tenfold), approximately six times higher than that of silica PC.

Phase-Field Simulations of Tunable Polar Topologies in Lead-Free Ferroelectric/Paraelectric Multilayers with Ultrahigh Energy-Storage Performance.

Dielectric capacitors are emerging energy-storage components that require both high energy-storage density and high efficiency. The conventional approach to energy-storage enhancement is polar nanodomain engineering via chemical modification. Here, a new approach of domain engineering is proposed by exploiting the tunable polar topologies that have been observed recently in ferroelectric/paraelectric multilayer films. Using phase-field simulations, it is demonstrated that vortex, spiral, and in-plane polar structures can be stabilized in BiFeO3 /SrTiO3 (BFO/STO) multilayers by tailoring the strain state and layer thickness. Various switching dynamics are realized in these polar topologies, resulting in relaxor-ferroelectric-, antiferroelectric-, and paraelectric-like polarization behaviors, respectively. Ultrahigh energy-storage densities above 170 J cm-3 and efficiencies above 95% are achievable in STO/BFO/STO trilayers. This strategy should be generally implementable in other multilayer dielectrics and offers a new avenue to enhancing energy storage by tuning the polar topology and thus the polarization characteristics.

Discussion on molecular dynamics (MD) simulations of the asphalt materials.

The application of asphalt materials in pavement engineering has been increasingly widespread and sophisticated over the past several decades. Variations in the properties of asphalt binder during mixing, transportation, and paving can affect the performance of asphalt pavement. However, the asphalt material is a non-homogeneous and complex organic substance, consisting of various molecules with widely various molecular weights, elemental compositions, and structures. This complexity leads to difficulties for researchers to clearly and immediately understand the properties of asphalt materials and their variations. The multi-scale research approach combines macroscopic experimental data and microscopic simulation results from a practical engineering perspective. It helps to improve the understanding of asphalt materials. The molecular dynamics (MD) simulation proposes a corresponding molecular model of asphalt material based on experimental data, and the simulation algorithm is able to derive properties similar to those of real asphalt. This paper provides a comprehensive review of the current studies on MD simulation of asphalt materials, including modeling, properties, and multi-scale analysis. As a key part of the computational simulation, this paper discusses the typical asphalt binder and asphalt-aggregate interface models constructed by different groups, and also presents their differences from real samples and their feasibility based on fundamental properties. After the introduction of molecular models, the extensive work made by researchers based on molecular models is categorically reviewed and discussed. The strengths and weaknesses of MD simulation methods in the study of asphalt materials are also summarized in order to provide the reader with a more comprehensive understanding of the relevant contents and to guide subsequent research.

Generation and properties of the new asphalt binder model using molecular dynamics (MD).

Asphalt binder is the main material for road pavement and building construction. It is a complex mixture composed of a large number of hydrocarbons with different molecular weights. The study of asphalt binders and asphalt concretes from a molecular perspective is an important means to understand the intricate properties of asphalt. Molecular dynamics simulation is based on Newton's law and predicts the microscopic performance of materials by calculating the intra- and intermolecular interactions. The asphalt binder can be divided into four components: saturates, aromatics, resins, and asphaltenes (SARA). A new molecular model of asphalt was proposed and verified in this study. Eight molecules selected from the literature were used to represent the four components of asphalt. The AMBER Cornell Extension Force Field was applied in this study to model building and the calculation of properties. The density of the asphalt model was calculated and compared with experimental results for validity verifications. The results show that the purposed model can be used to calculate the microscopic properties of the asphalt binder because the density of the model is close to the real value in the field. Besides, the proportions of different molecules in the model were adjusted to predict the relationship between the asphalt binder density and the hydrocarbon ratios and heteroatom contents of the molecular model. Moreover, the glass transition temperature of the asphalt binder model is predicted by the simulation of the heating process. The range of the glass transition temperature is determined by calculating the relationship between specific volume and temperature, and the calculated range is close to the experimental value.

The differentially expressed circular ribonucleic acids of primary hepatic carcinoma following liver transplantation as new diagnostic biomarkers for primary hepatic carcinoma.

Recent studies have shown that circular ribonucleic acids have differential expression in some diseases. This study compared the expression levels of five circular ribonucleic acids between patients of primary hepatic carcinoma following liver transplantation and healthy individuals for searching a new diagnostic biomarker about primary hepatic carcinoma. We chose differentially expressed targeted circular ribonucleic acids according to fold change ≥2.0 or ≤-2.0 between circular ribonucleic acids microarray of perioperative liver transplantation and normal controls. Then we used the Arraystar home-made micro-ribonucleic acid target prediction software based on TargetScan and miRanda to predict circular ribonucleic acid/micro-ribonucleic acid interactions. And we assess the expression levels of hsa_circ_100571, hsa_circ_400031, hsa_circ_102032, hsa_circ_103096, and hsa_circ_102347 in the peripheral blood of normal controls and liver transplantation patients before transplantation and on the first, third, and seventh days after transplantation by real-time quantitative polymerase chain reaction. We chose five circular ribonucleic acids, two of which have been correlated with micro-ribonucleic acid-related carcinoma recurrence after liver transplantation, hepatocellular carcinoma and analyzed their expression with 2-△△Ct method. The expression level of hsa_circ_100571 and hsa_circ_400031 on day 1 after liver transplantation was higher than pre-transplantation (p < 0.01), and these levels showed a declining trend on post-transplantation. The expression level of hsa_circ_102032 and hsa_circ_103096 on day 1 after liver transplantation was lower than pre-transplantation (p < 0.01) and decreased on post-transplantation. There were the significantly different expressions between the post-transplantation day 7 and normal control (p < 0.01). The expression level of hsa_circ_102347 on day 1 after liver transplantation was lower than pre-transplantation (p < 0.01). This expression showed a declining trend on post-transplantation, and the postoperative day 7 level was similar to normal control (p > 0.05). Five types of circular ribonucleic acid-related micro-ribonucleic acids had varying degrees of upregulation and downregulation between perioperative transplantation of primary hepatic carcinoma patients and normal controls; the hsa_circ_102347 is most likely to have association with primary hepatic carcinoma.

Field-assisted nanopatterning of metals, metal oxides and metal salts.

The tip-based nanofabrication method called field-assisted nanopatterning or FAN has now been extended to the transfer of metals, metal oxides and metal salts onto various receiving substrates including highly ordered pyrolytic graphite, passivated gold and indium-tin oxide. Standard atomic force microscope tips were first dip-coated using suspensions of inorganic compounds in solvent. The films prepared in this manner were non-uniform and contained inorganic nanoparticles. Tip-based nanopatterning on chosen substrates was conducted under high electric field conditions. The same tip was used for both nanofabrication and imaging. Arbitrary patterns were formed with dimensions that ranged from tens of microns to sub-20 nm and were controlled by tuning the tip bias during fabrication. Most tip-based nanopatterning techniques are limited in terms of the type of species that can be deposited and the type of substrates onto which the deposition occurs. With the successful deposition of inorganic species reported here, FAN is demonstrated to be a truly versatile tip-based nanofabrication technique that is useful for the deposition of a wide variety of both organic and inorganic species including small molecules, large molecules and polymers.

Self-assembly of long chain alkanes and their derivatives on graphite.

We combine scanning tunneling microscopy (STM) measurements with ab initio calculations to study the self-assembly of long chain alkanes and related alcohol and carboxylic acid molecules on graphite. For each system, we identify the optimum adsorption geometry and explain the energetic origin of the domain formation observed in the STM images. Our results for the hierarchy of adsorbate-adsorbate and adsorbate-substrate interactions provide a quantitative basis to understand the ordering of long chain alkanes in self-assembled monolayers and ways to modify it using alcohol and acid functional groups.

Thermal, sonochemical, and mechanical behaviors of single crystal [60]fullerene nanotubes.

Although related to conventional carbon nanotubes in both shape and construction, fullerene nanowhiskers and fullerene nanotubes have received far less attention. A modified liquid-liquid interfacial precipitation technique is described to produce relatively uniform batches of [60]fullerene nanotubes in high yield. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) reveal that the tubes possess approximately 100-nm inside diameters and 300-nm outside diameters. The [60]fullerene nanotubes degrade slowly at 180 degrees C, eventually collapsing into micron scale [60]fullerene discs and rods, as revealed by optical microscopy and AFM. Ultrasonic cavitation chops [60]fullerene nanotubes into smaller segments within seconds. Longer ultrasonic bathing leads to considerable structural damage in which the sidewalls rupture. Mechanical stress tests using an AFM microscope tip effectively dent and break [60]fullerene nanowhiskers, revealing a hollow interior.