Research progress of cholesteric liquid crystals with broadband reflection characteristics in application of intelligent optical modulation materials

Cholesteric liquid crystals（CLCs） have recently sparked an enormous amount of interest in the development of soft matter materials due to their unique ability to self-organize into a helical supra-molecular architecture and their excellent selective reflection of light based on the Bragg relationship.Nowadays,by the virtue of building the self-organized nanostructures with pitch gradient or non-uniform pitch distribution,extensive work has already been performed to obtain CLC films with a broad reflection band.Based on authors＇ many years＇ research experience,this critical review systematically summarizes the physical and optical background of the CLCs with broadband reflection characteristics,methods to obtain broadband reflection of CLCs,as well as the application in the field of intelligent optical modulation materials.Combined with the research status and the advantages in the field,the important basic and applied scientific problems in the research direction are also introduced.

Experimental Study on Ratio and Performance of Coal Gangue/Bottom Ash Geopolymer Double-Liquid Grouting Material

Mine grouting reinforcement and water plugging projects often require large amounts of grouting materials.To reduce the carbon emission of grouting material production,improve the utilization of solid waste from mining enterprises,and meet the needs of mine reinforcement and seepage control,a double-liquid grouting material containing a high admixture of coal gangue powder/bottom ash geopolymer was studied.The setting time,fluidity,bleeding rate,and mechanical properties of grouting materials were studied through laboratory tests,and SEM analyzed the microstructure of the materials.The results show that the total mixture of calcined gangue does not exceed 60%.And the proportion of bottom ash replacing cement should be within 30%.At the same time,the volume mixture of sodium silicate is 20%.And the water-solid ratio does not exceed 0.6.The stability of the slurry prepared under this ratio is good.The microstructure of the stone body is dense,and its strength can meet the requirements of rock reinforcement and seepage control.Its economic and environmental benefits are more significant than the traditional cement-silicate double-liquid grouting material.

Liquid metal material genome： Initiation of a new research track towards discovery of advanced energy materials

As the basis of modern industry, the roles materials play are becoming increasingly vital in this day and age. With many superior physical properties over conventional fluids, the low melting point liquid metal material, especially room-temperature liquid metal, is recently found to be uniquely useful in a wide variety of emerging areas from energy, electronics to medical sciences. However, with the coming enormous utilization of such materials, serious issues also arise which urgently need to be addressed. A biggest concern to impede the large scale application of room-temperature liquid metal technologies is that there is currently a strong shortage of the materials and species available to meet the tough requirements such as cost, melting point, electrical and thermal conductivity, etc. Inspired by the Material Genome Initiative as issued in 2011 by the United States of America, a more specific and focused project initiative was proposed in this paper--the liquid metal material genome aimed to discover advanced new functional alloys with low melting point so as to fulfill various increasing needs. The basic schemes and road map for this new research program, which is expected to have a worldwide significance, were outlined. The theoretical strategies and experimental methods in the research and development of liquid metal material genome were introduced. Particularly, the calculation of phase diagram （CALPHAD） approach as a highly effective way for material design was discussed. Further, the first-principles （FP） calculation was suggested to combine with the statistical thermo- dynamics to calculate the thermodynamic functions so as to enrich the CALPHAD database of liquid metals. When the experimental data are too scarce to perform a regular treatment, the combination of FP calculation, cluster variation method （CVM） or molecular dynamics （MD）, and CALPHAD, referred to as the mixed FP-CVM- CALPHAD method can be a promising way to solve the problem. Except for the theoretical strategies, several parallel processing experimental methods were also analyzed, which can help improve the efficiency of finding new liquid metal materials and reducing the cost. The liquid metal material genome proposal as initiated in this paper will accelerate the process of finding and utilization of new functional materials.

2D materials via liquid exfoliation:a review on fabrication and applications

Since graphene was discovered, the study of two-dimensional(2D) materials with atomic thickness has become a hot spot. To prepare different 2D materials,different methods have been groped, such as mechanical exfoliation, chemical vapor deposition(CVD), liquid-phase exfoliation. This review mainly introduced the sonication liquid-phase exfoliation, an effective method to prepare 2D materials. Compared with mechanical exfoliation and CVD methods, liquid-phase exfoliation is convenient and costeffective and provides high yield. We focused on both theoretical and experimental details of this method. This method was reviewed according to the development of 2D materials from graphene, h-BN to transition metal chalcogenides(TMDs) and black phosphorus nanosheets.We discussed the applications of liquid-exfoliated 2D materials including micro- and nanoelectrical devices,photoelectric devices, and energy storage devices.

One step sintering of homogenized bauxite raw material and kinetic study

A one-step sintering process of bauxite raw material from direct mining was completed, and the kinetics of this process was analyzed thoroughly. The results show that the sintering kinetics of bauxite raw material exhibits the liquid-phase sintering behavior. A small portion of impurities existed in the raw material act as a liquid phase. After X-ray diffraction analyses, scanning electron microscopy observations, and kinetics calculations, sintering temperature and heating duration were determined as the two major factors contributing to the sintering process and densification of bauxite ore. An elevated heating temperature and longer duration favor the densification process. The major obstacle for the densification of bauxite material is attributed to the formation of the enclosed blowhole during liquid-phase sintering.

Fundamentals of phase-only liquid crystal on silicon (LCOS) devices

This paper describes the fundamentals of phase-only liquid crystal on silicon(LCOS)technology,which have not been previously discussed in detail.This technology is widely utilized in high efficiency applications for real-time holography and diffractive optics.The paper begins with a brief introduction on the developmental trajectory of phase-only LCOS technology,followed by the correct selection of liquid crystal(LC)materials and corresponding electro-optic effects in such devices.Attention is focused on the essential requirements of the physical aspects of the LC layer as well as the indispensable parameters for the response time of the device.Furthermore,the basic functionalities embedded in the complementary metal oxide semiconductor(CMOS)silicon backplane for phase-only LCOS devices are illustrated,including two typical addressing schemes.Finally,the application of phase-only LCOS devices in real-time holography will be introduced in association with the use of cutting-edge computer-generated holograms.

Surface effects of liquid metal amoeba

Liquid metals(LM) such as eutectic gallium-indium and gallium-indium-tin are important functional liquid-state metal materials with many unique properties, which have attracted wide attentions especially from soft robot area. Recently the amoeba-like transformations of LM on the graphite surface are discovered, which present a promising future for the design and assemble of self-fueled actuators with dendritically deformable body. It appears that the surface tension of the LM can be significantly reduced when it contacts graphite surface in alkaline solution. Clearly, the specific surface should play a vital role in inducing these intriguing behaviors, which is valuable and inspiring in soft robot design. However, the information regarding varied materials functions underlying these behaviors remains unknown. To explore the generalized effects of surface materials in those intriguing behavior, several materials including glass, graphite, nickel and copper oxides(CuO) were comparatively investigated as substrate surfaces.Important results were obtained that only LM amoeba transformations were observed on graphite and CuO surfaces. In order to identify the proper surface condition for LM transformation, the intrinsic properties of substrate surfaces, such as the surface charge and roughness, as well as the specific interaction with LM like wetting behavior and mutual locomotion etc., were characterized. The integrated results revealed that LM droplet appears more likely to deform on surfaces with higher positive surface charge density, higher roughness and less bubble generation on them. In addition, another surface material,CuOx, is identified to own similar ability to graphite, which is valuable in achieving amoeba-like transformation. Moreover, this study offers a fundamental understanding of the surface properties in realizing LM amoeba transformations, which would shed light on packing and structure design of liquid metal-based soft device within multi-material system.

Studies of Water V. Five Phonons in Protonic Semiconductor Lattice Model of Pure Liquid Water

We report physics based confirmation（~1% RMS deviation）, by existing experimental data, of protonprohol（proton-hole） ion product（p H） and mobilities in pure liquid water（0-100℃, 1-atm pressure） anticipated from our melted-ice Hexagonal-Close-Packed（H_2O）_4Lattice Model. Five phonons are identified.（1） A propagating protonic phonon（520.9 meV from lone-pair-blue-shifted stretching mode of isolated water molecule） absorbed to generate a proton-prohol pair or detrap a tightly-bound proton.（2） Two（173.4 and 196.6 meV） bending-breathing protonic-proholic or protonic phonons absorbed during de-trapping-limited proton or proton-prohol mobilities.（3）Two propagating oxygenic-wateric Debye-Dispersive phonons（30.3 and 27.5 meV） absorbed during scatteringlimited proton or proton-prohol mobilities.