Lithium Metal-Compatible Antifluorite Electrolytes for Solid-State Batteries.

Lithium (Li) metal solid-state batteries feature high energy density and improved safety and thus are recognized as promising alternatives to traditional Li-ion batteries. In practice, using Li metal anodes remains challenging because of the lack of a superionic solid electrolyte that has good stability against reduction decomposition at the anode side. Here, we propose a new electrolyte design with an antistructure (compared to conventional inorganic structures) to achieve intrinsic thermodynamic stability with a Li metal anode. Li-rich antifluorite solid electrolytes are designed and synthesized, which give a high ionic conductivity of 2.1 × 10-4 S cm-1 at room temperature with three-dimensional fast Li-ion transport pathways and demonstrate high stability in Li-Li symmetric batteries. Reversible full cells with a Li metal anode and LiCoO2 cathode are also presented, showing the potential of Li-rich antifluorites as Li metal-compatible solid electrolytes for high-energy-density solid-state batteries.

A 3D Lithiophilic Host for Dendrite-Free Lithium Metal Anode via One-Step Carbonization of an Energetic Metal-Organic Framework.

Low Coulombic efficiency (CE) and safety issues are huge problems that hinder the practical application of Li metal anodes. Constructing Li host structures decorated with functional species can restrain the growth of Li dendrites and alleviate the great volume change. Here, a 3D porous carbonaceous skeleton modified with rich lithiophilic groups (Zn, ZnO, and Zn(CN)2 ) is synthesized as a Li host via one-step carbonization of a triazole-containing metal-organic framework. The nano lithiophilic groups serve as preferred sites for Li nucleation and growth, regulating a uniform Li+ flux and uniform current density distribution. In addition, the 3D porous network functions as a Li reservoir that provides rich internal space to store Li, thus alleviating the volumetric expansion during Li plating/stripping process. Thanks to these component and structural merits, an ultra-low overpotential for Li deposition is achieved, together with high CE of over 99.5% for more than 500 cycles at 1 mA cm-2 and 1 mAh cm-2 in half cells. The symmetric cells exhibit a prolonged cycling of 900 h at 1 mA cm-2 . The full cells by coupling Zn/ZnO/Zn(CN)2 @C-Li anode with LiFePO4 cathode deliver a high capacity retention of 94.3% after 200 cycles at 1 C.

Modulating the Coordination Chemistry of Cobalt Catalytic Sites by Ruthenium Species to Accelerate the Polysulfide Conversion Kinetics in Lithium-Sulfur Batteries.

The performance of lithium-sulfur batteries is compromised by the loss of sulfur as dissolved polysulfides in the electrolyte and consequently the polysulfide redox shutting effect. Accelerating the conversion kinetics of polysulfide intermediates into sulfur or lithium sulfide through electrocatalysis has emerged as a root-cause solution. Co-N-C composite electrocatalyst is commonly used for this purpose. It is illustrated here that how the effectiveness can be improved by modulating the coordination chemistry of Co-N-C catalytic sites through introducing Ru species (RuCo-NC). The well-dispersed Ru in the Co-NC carbon matrix altered the total charge distribution over the Co-N-C catalytic sites and led to the formation of electron-rich Co-N, which is highly active for the polysulfide conversion reactions. Using Ru to modulate the electronic structure in the Co-N-C configuration and the additional catalytic sites over the Ru-Nx species can manifest optimal adsorption behavior of polysulfides. Consequently, the sulfur cathode with RuCo-NC can reduce the capacity fade rate from 0.11 % per cycle without catalyst (initial capacity of 701 mAh g-1) to 0.054 % per cycle (initial capacity of 1074 mAh g-1) over 400 cycles at 0.2 C rate. The results of this study provide the evidence for a feasible catalyst modification strategy for the polysulfide electrocatalysis.

Exploring the Underlying Correlation between the Structure and Ionic Conductivity in Halide Spinel Solid-State Electrolytes with Neutron Diffraction.

The development of cutting-edge solid-state electrolytes (SSEs) entails a deep understanding of the underlying correlation between the structure and ionic conductivity. Generally, the structure of SSEs encompasses several interconnected crystal parameters, and their collective influence on Li+ transport can be challenging to discern. Here, we systematically investigate the structure-function relationship of halide spinel LixMgCl2+x (2 ≥ x ≥ 1) SSEs. A nonmonotonic trend in the ionic conductivity of LixMgCl2+x SSEs has been observed, with the maximum value of 8.69 × 10-6 S cm-1 achieved at x = 1.4. The Rietveld refinement analysis, based on neutron diffraction data, has revealed that the crystal parameters including cell parameters, Li+ vacancies, Debye-Waller factor, and Li-Cl bond length assume diverse roles in influencing ionic conductivity of LixMgCl2+x at different stages within the range of x values. Besides, mechanistic analysis demonstrates Li+ transport along three-dimensional pathways, which primarily governs the contribution to ionic conductivity of LixMgCl2+x SSEs. This study has shed light on the collective influence of crystal parameters on Li+ transport behaviors, providing valuable insights into the intricate relationship between the structure and ionic conductivity of SSEs.

Ternary Rotational Polyanion Coupling Enables Fast Li Ion Dynamics in Tetrafluoroborate Ion Doped Antiperovskite Li2OHCl Solid Electrolyte.

Li-rich antiperovskite (LiRAP) hydroxyhalides are emerging as attractive solid electrolyte (SEs) for all-solid-state Li metal batteries (ASSLMBs) due to their low melting point, low cost, and ease of scaling-up. The incorporation of rotational polyanions can reduce the activation energy and thus improve the Li ion conductivity of SEs. Herein, we propose a ternary rotational polyanion coupling strategy to fasten the Li ion conduction in tetrafluoroborate (BF4 -) ion doped LiRAP Li2OHCl. Assisted by first-principles calculation, powder X-ray diffraction, solid-state magnetic resonance and electrochemical impedance spectra, it is confirmed that Li ion transport in BF4 - ion doped Li2OHCl is strongly associated with the rotational coupling among OH-, BF4 - and Li2-O-H octahedrons, which enhances the Li ion conductivity for more than 1.8 times with the activation energy lowering 0.03 eV. This work provides a new perspective to design high-performance superionic conductors with multi-polyanions.

Diffusion-Mediated Nucleation and Growth of fcc and bcc Nanocrystal Superlattices with Designable Assembly of Freestanding 3D Supercrystals.

Diffusion-mediated assembly of octahedral PbS nanocrystals (NCs) in a confined antisolvent environment displays a primary burst nucleation and Ostwald ripening growth of rhombic bcc supercrystals, followed by a secondary seed-based nucleation and oriented attachment growth of triangle fcc supercrystals. As the diffusion proceeds from ethanol across a sharp interface into NC-suspended toluene, a burst nucleation of supercrystal seeds occurs, and such supercrystals are quickly developed into rhombic grains that have a bcc structure. At a critical size of 10 µm, an Ostwald ripening event appears to guide the supercrystal growth. Upon grain growth above 30 µm, the fcc supercrystals start a nucleation at two symmetrical tips of individual rhombic crystals. Such fcc supercrystals are developed with a triangle shape, and two triangles are combined with one bcc rhombus in-between to form a butterfly-like bowtie stacking structure. The fcc triangle wings grow larger at a reduction of bcc rhombus cores. As the bcc cores gradually fade, such butterfly-like bowtie crystals aggregate and undergo an oriented attachment process, leading to the formation of freestanding 3D triangle crystals that have a single fcc lattice. Analysis of experimental observations and defined diffusion parameters reveals that fast solvent diffusion and high-NC concentration promote the growth of rhombic bcc supercrystals, while slow solvent diffusion and low-NC concentration accelerate the development of triangle fcc supercrystals. Upon succeeding in designable growth of 3D fcc supercrystals, this study provides designing principles for controlled fabrication of supercrystals with desired superlattices for additional engineering and applications.

MiR-155 regulates M2 polarization of hepatitis B virus-infected tumour-associated macrophages which in turn regulates the malignant progression of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) initiated by hepatitis B virus (HBV) infection is a complicated process. MiR-155 can alter the immune microenvironment to affect the host's anti-infective ability. This study investigated the mechanism by which miR-155 affects tumour-associated macrophage (TAM) polarization at a molecular level, thus affecting the malignant progression of HBV+ HCC. MiR-155 and TAM-related cytokine expression were analysed by qRT-PCR. The distribution of TAMs was detected by immunohistochemistry. The effect of the aberrant miR-155 expression on macrophage polarization was examined by flow cytometry. The targeted relationship was verified by dual-luciferase assay, and the protein level of src homology 2 domain-containing inositol polyphosphate 5-phosphatase 1 (SHIP1) was detected by western blot. The proliferation of HCC cells was examined by CCK-8 and colony formation assays. Invasion and migration of HCC cells were detected by transwell assay. In HBV+ HCC tissues, miR-155 was significantly highly expressed and the number of CD206-positive TAM (CD206+ TAM) and CD68-positive TAM (CD68+ TAM) were higher than those in HBV- HCC tissues. In addition, miR-155 overexpression significantly promoted M2-type macrophage polarization, whilst miR-155 silencing expression significantly promoted M1-type macrophage polarization. Besides, the miR-155/SHIP1 axis accelerated HCC cell invasion, proliferation and migration by inducing M2-type macrophage polarization. MiR-155 accelerates HCC cell proliferation, migration and invasion by targeting SHIP1 expression and inducing macrophage M2 polarization. This finding provides new insights into the development of novel therapeutic strategies for combatting HBV+ HCC and a new reference for exploring anti-tumour immunotherapy.

GmMDE genes bridge the maturity gene E1 and florigens in photoperiodic regulation of flowering in soybean.

Soybean (Glycine max) is highly sensitive to photoperiod, which affects flowering time and plant architecture and thus limits the distribution range of elite soybean cultivars. The major maturity gene E1 confers the most prominent effect on photoperiod sensitivity, but its downstream signaling pathway remains largely unknown. Here, we confirm that the encoded E1 protein is a transcriptional repressor. The expression of seven GmMDE genes (Glycine max MADS-box genes downregulated by E1) was suppressed when E1 was overexpressed and promoted when E1 was knocked out through clustered regularly-interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9)-mediated mutagenesis. These GmMDEs exhibited similar tissue specificity and expression patterns, including in response to photoperiod, E1 expression, and E1 genotype. E1 repressed GmMDE promoter activity. Results for two GmMDEs showed that E1 epigenetically silences their expression by directly binding to their promoters to increase H3K27me3 levels. The overexpression of GmMDE06 promoted flowering and post-flowering termination of stem growth. The late flowering phenotype of E1-overexpressing soybean lines was reversed by the overexpression of GmMDE06, placing GmMDE06 downstream of E1. The overexpression of GmMDE06 increased the expression of the soybean FLOWERING LOCUS T orthologs GmFT2a and GmFT5a, leading to feedback upregulation of GmMDE, indicating that GmMDE and GmFT2a/GmFT5a form a positive regulatory feedback loop promoting flowering. GmMDE06 also promoted post-flowering termination of stem growth by repressing the expression of the shoot identity gene Dt1. The E1-GmMDEs-GmFT2a/5a-Dt1 signaling pathway illustrates how soybean responds to photoperiod by modulating flowering time and post-flowering stem termination.

EUV mask model based on modified Born series.

Mask model is a critical part of computational lithography (CL). Owing to the significant 3D mask effects, it is challenging to accurately and efficiently calculate the near field of extreme ultraviolet (EUV) masks with complex patterns. Therefore, a method based on the modified Born series (MBS) was introduced for EUV mask modeling. With comparable accuracy, the MBS method was two orders of magnitude faster than the finite-difference time-domain method for the investigated examples. Furthermore, the time required for MBS was further reduced when the mask pattern was slightly changed. The proposed method shows great potential for constructing an accurate 3D mask model in EUV CL with high efficiency.

A novel 7-base pair deletion at a splice site in MS-2 impairs male fertility via premature tapetum degradation in common bean (Phaseolis vulgaris L.).

KEY MESSAGE: A novel splice-site mutation in the P. vulgarisgene for TETRAKETIDE α-PYRONE REDUCTASE 2 impairs male fertility, and parthenocarpic pod development can be improved by external application of IAA. Snap bean (Phaseolus vulgaris L.) is an important vegetable crop in many parts of the world, and the main edible part is the fresh pod. Here, we report the characterization of the genic male sterility (ms-2) mutant in common bean. Loss of function of MS-2 accelerates degradation of the tapetum, resulting in a complete male sterility. Through fine-mapping, co-segregation, and re-sequencing analysis, we identified Phvul.003G032100, which encodes the TETRAKETIDE α-PYRONE REDUCTASE 2 (PvTKPR2) protein in common bean, as the causal gene for MS-2. PvTKPR2 is predominantly expressed at the early stages of flower development. A novel 7-bp (+ 6028 bp to + 6034 bp) deletion mutation spans the splice site between the fourth intron and fifth exon, leading to a 9-bp deletion in transcribed mRNA and a 3-amino acid (G210M211V212) deletion in the protein coding sequence of the PvTKPR2ms-2 gene. The 3-D structural changes in the protein due to the mutation may impair the activities of NAD-dependent epimerase/dehydratase and the NAD(P)-binding domains of PvTKPR2ms-2 protein. The ms-2 mutant plants produce many small parthenocarpic pods, and the size of the pods can be doubled by external application of 2 mM indole-3-acetic acid (IAA). Our results demonstrate that a novel mutation in PvTKPR2 impairs male fertility through premature degradation of the tapetum.

In-situ calibration of the objective lens of an angle-resolved scatterometer for nanostructure metrology.

Due to the advantages of being non-contact, non-destructive, highly efficient, and low in cost, scatterometry has emerged as a powerful technique for nanostructure metrology. In this paper, we propose an angle-resolved scatterometer composed of a scattered light acquisition channel and a spatial imaging channel, which is capable of detecting multi-order diffracted light in a single measurement. Since the high numerical aperture objective lens is usually employed in an angle-resolved scatterometer, the polarization effect of the objective lens introduced by the non-normal incidence and installation stress should be considered. An in-situ calibration method for the objective lens's polarization effects is proposed, in which a known analyzer is appended to the output light path to enable the extraction of the ellipsometric parameters of isotropic samples. Then the polarization effect of the objective lens can be determined in-situ by fitting the measured ellipsometric parameters to the calculated ones. With the objective lens polarization effect being considered, significant improvements in the accuracy and repeatability precision can be achieved in the metrology of the film thickness and grating topography parameters.

Dysfunction of an Anaphase-Promoting Complex Subunit 8 Homolog Leads to Super-Short Petioles and Enlarged Petiole Angles in Soybean.

Plant height, petiole length, and the angle of the leaf petiole and branch angles are crucial traits determining plant architecture and yield in soybean (Glycine max L.). Here, we characterized a soybean mutant with super-short petioles (SSP) and enlarged petiole angles (named Gmssp) through phenotypic observation, anatomical structure analysis, and bulk sequencing analysis. To identify the gene responsible for the Gmssp mutant phenotype, we established a pipeline involving bulk sequencing, variant calling, functional annotation by SnpEFF (v4.0e) software, and Integrative Genomics Viewer analysis, and we initially identified Glyma.11G026400, encoding a homolog of Anaphase-promoting complex subunit 8 (APC8). Another mutant, t7, with a large deletion of many genes including Glyma.11G026400, has super-short petioles and an enlarged petiole angle, similar to the Gmssp phenotype. Characterization of the t7 mutant together with quantitative trait locus mapping and allelic variation analysis confirmed Glyma.11G026400 as the gene involved in the Gmssp phenotype. In Gmssp, a 4 bp deletion in Glyma.11G026400 leads to a 380 aa truncated protein due to a premature stop codon. The dysfunction or absence of Glyma.11G026400 caused severe defects in morphology, anatomical structure, and physiological traits. Transcriptome analysis and weighted gene co-expression network analysis revealed multiple pathways likely involved in these phenotypes, including ubiquitin-mediated proteolysis and gibberellin-mediated pathways. Our results demonstrate that dysfunction of Glyma.11G026400 leads to diverse functional consequences in different tissues, indicating that this APC8 homolog plays key roles in cell differentiation and elongation in a tissue-specific manner. Deciphering the molecular control of petiole length and angle enriches our knowledge of the molecular network regulating plant architecture in soybean and should facilitate the breeding of high-yielding soybean cultivars with compact plant architecture.

Femtosecond laser induced damaging inside fused silica detected by a single-pulse ultrafast measurement system.

The dynamics of damage inside the fused silica induced by a femtosecond laser has been characterized by a single-pulse ultrafast measurement system that is built upon the pump-probe mechanism. Our investigation disclosed the quantitative relationship between the size of the damaged area and the pulse energy. The dynamic measurement experiments showed that the radial size of the damaged area increased rapidly from 0 to 21 µm within ∼10 ps before stabilizing at 21 µm with the pulse energy of 1.1 mJ, which follows the rule of Boltzmann function. Moreover, we demonstrated that the structure inside the damaged area kept changing for about 200 ps before the formation of a double-void structure. The developed system alongside the proposed analysis method is expected to be of great importance in understanding the dynamics of laser-induced damage process in laser micromachining.

Decreased nutrient digestibility due to viscosity is independent of the amount of dietary fibre fed to growing pigs.

Fibre content and its effect on chyme viscosity are associated with changes in the digestive system of humans and pigs. It is unclear if fibre content and viscosity affect digestive function independently or interactively. We evaluated apparent ileal digestibility (AID) of nutrients and intestinal function in thirty-six ileal-cannulated barrows fed for 29 d either maize-soyabean meal (MSBM) or high-fibre MSBM + 30 % distillers dried grains with solubles (MSBM + DDGS) modified to three levels of viscosity by adding 5 % non-viscous cellulose (CEL), 6·5 % medium-viscous carboxymethylcellulose (MCMC) or 6·5 % high-viscous CMC (HCMC). Digesta were collected on days 27 and 28 and intestinal samples on day 29. Feeding CMC, regardless of fibre content, increased viscosity of whole digesta (P = 0·003) and digesta supernatant (P < 0·0001) compared with CEL. Feeding MSBM + DDGS or CMC decreased AID of DM (P = 0·003; P < 0·0001) and crude protein (P = 0·02; P < 0·0001) compared with MSBM or CEL. Feeding CMC regardless of fibre content increased jejunal crypt depth (P = 0·02) and ileal goblet cell area (P = 0·004) compared with CEL. Adding DDGS or CMC did not affect villus height and gene expression of jejunal monosaccharide and amino acid transporters. Feeding HCMC, regardless of fibre content, elevated amylase activity by 46 and 50 % in jejunal (P = 0·03) and ileal digesta (P = 0·01) compared with CEL. In summary, diets with increased viscosity decreased nutrient digestibility and induced intestinal changes that were independent of the amount of fibre fed.

sp2-to-sp3 transitions in graphite during cold-compression.

Pressure-induced sp2-to-sp3 transitions in graphite have been studied for decades by experiments and simulations. In general, pressures of 15-18 GPa are needed to initiate structural transitions in graphite at room temperature, and the high-pressure phases are usually unquenchable, as evidenced by in situ resistivity and optical transmittance measurements, X-ray diffraction (XRD), and inelastic X-ray scattering (IXS). However, our in situ Raman results show that the onset transition pressure can be as low as 9.7 GPa when using the methanol-ethanol-water (MEW) mixture as the pressure-transmitting medium (PTM), indicated by an additional GD Raman peak caused by the sp3 bonding between adjacent graphite layers. Moreover, using a combination of XRD, Raman, X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), we show that a small amount of sp3 bonds associated with a unique feature of cross stacking are present in the recovered samples. Our findings will be useful to understand the intricate structural transitions in graphite-like materials under compression.

Pressure-induced phase transitions and superconductivity in a quasi-1-dimensional topological crystalline insulator α-Bi4Br4.

Great progress has been achieved in the research field of topological states of matter during the past decade. Recently, a quasi-1-dimensional bismuth bromide, Bi4Br4, has been predicted to be a rotational symmetry-protected topological crystalline insulator; it would also exhibit more exotic topological properties under pressure. Here, we report a thorough study of phase transitions and superconductivity in a quasihydrostatically pressurized α-Bi4Br4 crystal by performing detailed measurements of electrical resistance, alternating current magnetic susceptibility, and in situ high-pressure single-crystal X-ray diffraction together with first principles calculations. We find a pressure-induced insulator-metal transition between ∼3.0 and 3.8 GPa where valence and conduction bands cross the Fermi level to form a set of small pockets of holes and electrons. With further increase of pressure, 2 superconductive transitions emerge. One shows a sharp resistance drop to 0 near 6.8 K at 3.8 GPa; the transition temperature gradually lowers with increasing pressure and completely vanishes above 12.0 GPa. Another transition sets in around 9.0 K at 5.5 GPa and persists up to the highest pressure of 45.0 GPa studied in this work. Intriguingly, we find that the first superconducting phase might coexist with a nontrivial rotational symmetry-protected topology in the pressure range of ∼3.8 to 4.3 GPa; the second one is associated with a structural phase transition from monoclinic C2/m to triclinic P-1 symmetry.

A Three-Dimensional Structured Light Vision System by Using a Combination of Single-Line and Three-Line Lasers.

A multi-line structured light measurement method that combines a single-line and a three-line laser, in which precision sliding rails and displacement measurement equipment are not required, is proposed in this paper. During the measurement, the single-line structured light projects onto the surface of an object and the three-line structured light remains fixed. The single-line laser is moved and intersects with the three-line laser to form three intersection points. The single-line light plane can be solved using the camera coordinates of three intersection points, thus completing the real-time calibration of the scanned light plane. The single-line laser can be scanned at any angle to determine the overall complete three-dimensional (3D) shape of the object during the process. Experimental results show that this method overcomes the difficulty of obtaining information about certain angles and locations and can effectively recover the 3D shape of the object. The measurement system's repetition error is under 0.16 mm, which is sufficient to measure the 3D shapes of complicated workpieces.

In Situ Constructing the Kinetic Roadmap of Octahedral Nanocrystal Assembly Toward Controlled Superlattice Fabrication.

Crystallization and growth of anisotropic nanocrystals (NCs) into distinct superlattices were studied in real time, yielding kinetic details and designer parameters for scale-up fabrication of functional materials. Using octahedral PbS NC blocks, we discovered that NC assembly involves a primary lamellar ordering of NC-detached Pb(OA)2 molecules on the front-spreading solvent surfaces. Upon a spontaneous increase of NC concentration during solvent processing, PbS NCs preferentially self-assembled into an orientation-disordered face-centered cubic (fcc) superlattice, which subsequently transformed into a body-centered cubic (bcc) superlattice with single NC-orientational ordering across individual domains. Unlike the deformation-based transformation route claimed previously, this solid-solid phase transformation involved a hidden intermediate formation of a lamellar-confined liquid interface at cost of the disassembly (melting) of small fcc grains. Such highly condensed and liquidized NCs recrystallized into the stable bcc phase with an energy reduction of 1.16 kBT. This energy-favorable and high NC-fraction-driven bcc phase grew as a 2D film at a propagation rate of 0.74 µm/min, smaller than the 1.23 µm/min observed in the early nucleated fcc phase under a dilute NC environment. Taking such insights and defined parameters, we designed experiments to manipulate the NC assembly pathway and achieved scalable fabrication of a large/single bcc supercrystal with coherent ordering of NC translation and atomic plane orientation. This study not only provides a design avenue for controllable fabrication of a large supercrystal with desired superlattices for application but also sheds new light on the nature of crystal nucleation/growth and phase transformation by extending the lengths from the nanoscale into the atomic scale, molecular scale, and microscale levels.

Pressure-induced novel nitrogen-rich aluminum nitrides: AlN6, Al2N7 and AlN7 with polymeric nitrogen chains and rings.

Pressure-induced non-molecular phases of polymeric nitrogen have potential applications in the field of energetic materials. Here, through a structural search method combined with first-principles calculations, we have predicted four novel nitrogen-rich aluminum nitrides C2/m-AlN6, Cm-Al2N7, C2-Al2N7 and P1-AlN7. Nitrogen atoms polymerize into infinite chains in C2/m-AlN6, C2-Al2N7 and P1-AlN7 structures and form N3 chains and N4 rings in Cm-Al2N7. C2/m-AlN6 is stable in the pressure range from 30 to 80 GPa and Cm-Al2N7, C2-Al2N7 and P1-AlN7 are metastable in the pressure ranges of 35-65, 65-80 and 41-80 GPa, respectively. The present study predicts that C2/m-AlN6 has a superconducting transition temperature of 18.9 K at 0 GPa and can be quenched and recovered under ambient conditions. The energy densities of C2/m-AlN6, Cm-Al2N7, C2-Al2N7 and P1-AlN7 compounds are expected to be 4.80, 4.59, 5.46 and 5.59 kJ g-1, respectively, due to their high nitrogen content, indicating that they have potential to be high-energy density materials. The calculated Vickers hardness of C2/m-AlN6, Cm-Al2N7, Cm-Al2N7 and P1-AlN7 is 43.86, 39.32, 63.96 and 33.58 GPa, respectively, showing that the novel nitrogen-rich aluminum nitrides are potential superhard materials as well. This study may encourage further experimental exploration of high N content superhard or high-energy density nitrides.

Nonuniform depolarization properties of typical nanostructures and potential applications.

Nonuniform depolarization properties of ${\text{SiO}_2}$SiO2 thin film, two-dimensional (2D) Si grating, and three-dimensional Si cylinder grating, were systematically investigated by Lu-Chipman decomposition. We find that introducing surface profiles with dimensions comparable to the detecting wavelengths can lead to obvious nonuniform depolarization, and control of the sample azimuth can manipulate the uniformity of the depolarizer components. The results indicate that the 2D nanostructure shows obvious nonuniform depolarization at 0° and 90° azimuths, while almost uniform depolarization at 45° azimuth. These discovered phenomena may give rise to some potential applications, such as the detection of the existence of nanostructures without a priori information about the sample, and the design of a uniform or nonuniform depolarizer.