Strong Reflection Research Articles

Evidence for moth pollination in a rhinomyiophilous Erica species from the Cape Floristic Region of South Africa.

Contrasting pollination syndromes in closely related species suggest that floral trait divergence is associated with differences in pollination system, but empirical observations are required to confirm syndrome-based predictions. We present a comparative study of two closely related Erica species with contrasting pollination syndromes from the Cape Floristic Region of South Africa. Ericacylindrica has narrowly tubular pale and strongly scented flowers and is known to be hawkmoth-pollinated. The closely related Ericainfundibuliformis has bright flower colours and appears to lack scent, traits that are suggestive of pollination by long-tongued nemestrinid flies (rhinomyiophily). Floral trait measurements revealed that both species exhibit predominantly upright flower orientation and elongated floral tubes, although tube length of E.infundibuliformis is consistently greater than that of E.cylindrica. For both species, petals are brighter than floral tube surfaces, but flowers of E.cylindrica lack the strong UV reflectance found in E.infundibuliformis. Nectar of E.infundibuliformis is more concentrated and produced in larger volumes. Scent composition, but not evening scent emission rates, differed between the species: scent of E.cylindrica is dominated by aromatic compounds, whereas scent of E.infundibuliformis is dominated by (E)-ocimene and other terpenoid compounds and is emitted at higher rates during the day than the evening. Pollinator observations contradicted trait-based predictions: although a single nemestrinid fly captured in the vicinity of E.infundibuliformis did carry Erica pollen, almost all other diurnal flower visitors were nectar-robbing Hymenoptera which did not carry Erica pollen. Contrary to predictions, at two sites and over two flowering seasons, flowers were consistently visited in the evenings by several species of settling moths and hawkmoths which carried pollen, almost exclusively of Erica, on their proboscides. Our findings thus suggest that, despite objective differences in key floral traits between the closely related hawkmoth-pollinated E.cylindrica and E.infundibuliformis, moths are also important pollinators of E.infundibuliformis. A bimodal pollination system involving predominant pollination by moths and occasional visits by long-proboscid flies could partially reconcile findings with predictions. Our study further suggests that hawkmoth pollination may be more widespread in both Erica and the broader Cape flora than has hitherto been assumed and emphasises the importance of nocturnal pollinator observations.

Envelope normalized reflection waveform inversion

AbstractThe reflection waveform inversion has the capability to reconstruct the background velocity model using only the reflection data by employing a migration/demigration process. Utilizing the waveform discrepancy to update the background velocity model, the conventional reflection waveform inversion method heavily relies on the true‐amplitude migration/demigration technique to reproduce the primary amplitude information from the observed reflections. We can reproduce the amplitude of observed reflections by performing least‐squares reverse time migration to estimate the reflectivity in each iteration. However, this strategy is quite time‐consuming. To avoid the need for the true‐amplitude migration/demigration or least‐squares reverse time migration, we develop an amplitude‐independent reflection waveform inversion method that uses an envelope‐normalized objective function. The envelope‐normalized waveform difference can extract the phase residuals accurately as a function of time. Compared with the global energy–normalized misfit, our proposed envelope‐normalized objective function is essentially a phase‐matched measurement. At the same time, due to the amplitude independence of our proposed objective function, the subsequent weak reflections contribute with a similar weight to the total value of the misfit as the strong early reflections do. This makes it possible to recover the deep subsurface velocity. Synthetic data of the Sigsbee model and marine streamer field data applications validate that our amplitude‐independent reflection waveform inversion method can further improve the resolution and accuracy by aligning the reflection events of synthetic and observed data phase to phase without the need to perform true‐amplitude migration/demigration or least‐squares reverse time migration as in conventional reflection waveform inversion.

A new rhombohedral phase and its 48 variants in β titanium alloy

A new rhombohedral phase (termed R′) in a solution−aging-treated titanium alloy (Ti−4.5Al−6.5Mo−2Cr− 2Nb−1V−1Sn−1Zr, wt.%) was identified. Its accurate Bravais lattice parameters were determined by a novel unit cell reconstruction method based on conventional selected-area electron diffraction (SAED) technique. The orientation relationship between R′ phase and BCC phase was revealed. The results show that the R′ phase is found to have 48 crystallographically equivalent variants, resulting in rather complicated SAED patterns with high-order reflections. A series of in-situ SAED patterns were taken along both low- and high-index zone axes, and all weak and strong reflections arising from the 48 variants were properly explained and directly assigned with self-consistent Miller indices, confirming the presence of the rhombohedral phase. Additionally, some criteria were also proposed for evaluating the indexed results, which together with the Bravais lattice reconstruction method shed light on the microstructure characterization of even unknown phases in other alloys.

Self‐Standing Chiral Covalent Organic Framework Thin Films with Full‐Color Tunable Guest‐Induced Circularly Polarized Luminescence

Exploring self‐standing chiral covalent organic framework (CCOF) thin films with controllable circularly polarized luminescence (CPL) is of paramount significance but remains challenging. Herein, we demonstrate the first example of self‐standing CCOF films employing a polymerization‐dispersion‐filtration strategy. Pristine, low‐quality CCOF films were produced by interfacial polymerization and then re‐dispersed into COF colloidal solutions. Via vacuum assisted assembly, these COF colloids were densely stacked and assembled into self‐standing, pure chiral COF films (L‐/D‐CCOF‐F) that were transparent, smooth, crack‐free and highly crystalline. These films were tunable in thicknesses, areas, and roughness, along with strong diffuse reflectance circular dichroism (DRCD) and cyan CPL signals, showing an intrinsic luminescence asymmetric factor (glum) of 4.3×10‐3. Furthermore, these COF films served as host adsorbents to load various achiral organic dye guests through adsorption. The effective chiral transfer and energy transfer between CCOF‐F and achiral fluorescent dyes endowed the dyes with strong chirality and tunable DRCD, resulting in intense, full‐color‐tunable solid‐state CPL. Notably, the ordered arrangement of dye guest molecules within the preferentially oriented chiral pores of CCOF‐F contributed to an amplified |glum| factor of 7.2×10‐2, which is state‐of‐the‐art for COF‐based CPL materials. This work provides new insights into the design and fabrication of self‐standing chiral COF films.

Lithofacies identification of deep coalbed methane reservoir based on high-resolution seismic inversion

During the exploration and development of deep coalbed methane (CBM), delineating the thickness of coal seam and lithofacies of the roof and floor is one of the major challenging tasks. In past attempts, the prediction methods of these parameters have been limited to the conventional inversion. However, the effect of coal shielding on adjacent reflecting layers restricts the identification of underlying sand effectively by conventional inversion. Also, the depth at which the deep CBM zone is located (1,500–2000 m) produces a significant overlap of P-wave impedance and Vp/Vs of sands and shale which increases classification uncertainty between these two lithofacies. We proposed a new workflow for high-precision quantitative seismic interpretation of deep CBM reservoir. Not only P-wave impedance but also GR is selected as the optimized attributes for lithofacies classification. To reduce the effect of strong reflection of coal seam and identifying thin coal layers, the seismic waveform indication inversion method is used to obtain high-resolution results of P-wave impedance and GR. It uses horizontal changes in seismic waveforms to reflect lithological assemblage characteristics for facies-controlled constraints. Then, Bayesian classification theory is used to achieve three-dimensional lithofacies classification with multi-source data. To improve the continuity and accuracy of the interpreted results, a Markov chain is applied in the Bayesian rule as the spatial prior constraint. A well-associated synthetic test and field data application in Ordos Basin demonstrates the accuracy of the proposed workflow. Compared with conventional inversion, the results of proposed workflow showed higher resolution and accuracy. By providing a new solution for the identification of roof and floor lithofacies of deep CBM reservoir, this workflow aims to contribute to the better exploration and development of deep CBM.

Enhancing Defect-Induced Dipole Polarization Strategy of SiC@MoO3 Nanocomposite Towards Electromagnetic Wave Absorption

HighlightsOxygen-vacancy-rich SiC@MoO3 nanocomposite with strong reflection loss (− 50.49 dB at 1.27 mm thickness) and broadband absorption band (8.72 GHz at 2.68 mm thickness) were constructed via in situ etching strategy.The presence of oxygen vacancy leads to an increased conductive loss and defect-induced dipole polarization, which plays significant role in attenuating the incident electromagnetic wave.

Enhanced electromagnetic wave absorption of La3+–Zr4+ cosubstituted M−type barium hexaferrite

The development and breakthrough of electronic information technology have led to a profound focus on exploring new millimeter-wave absorbing materials. Herein, La–Zr ions co-substituted barium ferrite BaxLa1−xZrxFe12−xO19 (BLZFO) was prepared using a sol–gel method. BaFe12O19 possesses a dual loss mechanism (electrical/magnetic) and exhibits a natural resonance frequency of ∼ 45 GHz, making it effective for millimeter-wave absorption. The presence of La–Zr ions enhances the electromagnetic parameters of the material, improving its attenuation ability and optimizing impedance matching. Consequently, a wide, effective absorption frequency band and a minimal matching thickness are achieved. Specifically, within the 26.5–40 GHz range (Ka-band), BLZFO (x = 0.4) demonstrates an effective absorption bandwidth of 12.15 GHz, an optimal reflection loss of − 21.17 dB, and a corresponding matching thickness of 0.6 mm. This material not only exhibits strong reflection loss but also meets the requirements of an effective absorption frequency bandwidth and a small matching thickness, underscoring its profound importance for millimeter-wave absorption material research.

Biologically inspired shell-hollow particles for designing efficient passive all-sky radiative cooling

Passive radiation cooling (PRC), as the most promising technology to meet future cooling needs, has attracted great interest. However, there are still huge challenges in manufacturing high-efficiency and low-cost radiant coolers suitable for all-day use. Here, we report a secondary micro-nano shell-hollow structure based on blending method, inspired by the African white beetle Goliathus goliatus. Due to the difference in reflectance between the shell and the internal air, compared with the homogeneous particles, the scattered light has a changed optical path at the interface of the core (air) and the shell (SiO2), and most of the light escapes from the particles, showing strong total internal reflection. The design ingeniously deposits the nano-sized shell-hollow structure on the surface of the micron-sized shell-hollow structure, achieving high solar reflectance (95 ​%)and excellent long-wave infrared emissivity (94 ​%). Sub-ambient cooling of 7.8 and 4.7 ​°C can be achieved at night and daytime, respectively. Silica microspheres with shell and hollow structure can be prepared by soft template method, which is mature, reliable, simple and cheap.Our work provides new ideas for the design and manufacture of high-performance Passive all-day radiative cooling (PARC).

A moderate-Ti lunar mare soil simulant: IGG-01

Lunar soil simulants play a crucial role in scientific research, payload tests and in-situ resource utilization (ISRU) experiments. However, the currently available lunar soil simulants are either low in TiO2 content (≤3 wt%) or high in TiO2 content (≥6.7 wt%), despite orbital observations indicating lunar soils with moderate TiO2 content being widely distributed on the lunar surface. In December 2020, China's Chang'e−5 (CE-5) mission successfully returned a new mare soil sample characterized by high FeO content (22.5 wt%) and moderate TiO2 content (5.5 wt%), providing an opportunity to develop moderate-TiO2 lunar soil simulants. This study presents a newly developed simulant of the CE-5 lunar soil named IGG-01, which closely replicates the major physical and chemical properties of the CE-5 lunar soil. The median particle size of IGG-01 is 68.69 ± 4.44 μm, and its estimated specific surface area is 0.34 m2/g. It contains 17.6 wt% FeO and 4.8 wt% TiO2. It consists of pyroxene (49.3 wt%), plagioclase (40.9 wt%), ilmenite (6.1 wt%), and olivine (3.7 wt%), with specific gravity and bulk density are 3.33 g/cm³ and 1.86 g/cm³, respectively. The friction angle is 41.8°, and the cohesion is 19.2 kPa. It exhibits strong and weak reflectance absorption features in the 1 and 2 μm band centers. The physical properties of IGG-01 are also comparable to those of Apollo samples and typical lunar mare soil simulants. The unique chemical composition of IGG-01 makes it suitable for various scientific and engineering experiments, including but not limited to the study of dusty plasma migration, water formation via solar wind injection, oxygen preparation via hydrogen reduction, and tests involving the movement of rovers and excavation equipment.

Fabrication of 3D micro-flower structured BiFeO3 growing on rGO nanosheets for enhanced electromagnetic wave absorption

Because of the distinctive structure and superior properties of graphene and its derivatives, which have been widely studied in the field of electromagnetic wave (EMW) absorption. However, the impedance mismatch caused by excessive conductivity of graphene and the single loss mechanism greatly limit its application. Herein, we prepare 3D micro-flower structured BiFeO3 grown on graphene oxide nanosheets (BiFeO3-rGO) to both improve the impedance matching and introduce abundant interfacial polarization loss. Moreover, the electromagnetic parameters of the materials are adjusted by changing the ratio of BiFeO3 and rGO to obtain prominent EMW absorption and satisfactory impedance matching performances. More importantly, the conductive loss and polarization loss of the materials are quantitatively analyzed to further explore the loss mechanism of EMW. As a result, the fabricated BiFeO3-rGO 1:1 and BiFeO3-rGO 2:1 both achieve remarkable EMW absorption performances with strong reflection loss (RL) of −49.5 and −45.3 dB and broad effective absorption bandwidth (EAB) of 8.12 and 8.08 GHz with a low filling contents of 5 %. This work demonstrates that polarization loss is as important as conduction loss and the key point to further improve the EMW absorption performance is to crack the code of polarization loss.

A case-history using gravity data to validate alternate interpretations of the material below a deep seismic reflector in the Matheson area of Ontario, Canada

Gravity data are ‘nonunique’ in that a gravity anomaly can be explained by many bodies with different properties. Similarly, in seismic data, the strength of a reflection is dependent on the product of the density and the seismic velocity, so the nature of a reflection cannot be used to determine the density below an interface when the velocity is unknown. In a previous gravity study, we had concentrated on shallow features (model α), which implicitly assumed that a number of deeper reflections were due to an anomalous layer, thick enough to cause reflections from its upper and lower surfaces that do not cancel and that the density above and below this thick layer were the same. An alternate possibility is that the material below some of the reflections is lower density material called the Deloro assemblage. In order to test this hypothesized model (model β), we reinterpreted the seismic sections and repeated the gravity study. In order to allow for the deeper low-density material and account for some shallower reflectors having Deloro below, we had to make the Porcupine assemblage, which is shallow and even lower density than the Deloro, thinner in places. We found that the gravity data could be explained with the Deloro assemblage below the reflectors. The top of this hypothesized Deloro assemblage varies from 7.5 km in the east to 3 km in the west of the study area. Both models and are consistent with the gravity and seismic data, but model is also consistent with the Deloro being mapped outcropping to the west of the study area and a strong reflector (a banded iron formation) often being observed at the top of the Deloro. Our case study illustrates that modelling and interpretation should often be revised when new information becomes known.

GPU-accelerated OCT imaging: Real-time data processing and artifact suppression for enhanced monitoring of 3D bioprinted tissues and vascular-like networks

Optical coherence tomography (OCT) imaging technology has significant advantages in in situ and noninvasive monitoring of biological tissues. However, it still faces the following challenges: including data processing speed, image quality, and improvements in three-dimensional (3D) visualization effects. OCT technology, especially functional imaging techniques like optical coherence tomography angiography (OCTA), requires a long acquisition time and a large data size. Despite the substantial increase in the acquisition speed of swept source optical coherence tomography (SS-OCT), it still poses significant challenges for data processing. Additionally, during in situ acquisition, image artifacts resulting from interface reflections or strong reflections from biological tissues and culturing containers present obstacles to data visualization and further analysis. Firstly, a customized frequency domain filter with anti-banding suppression parameters was designed to suppress artifact noises. Then, this study proposed a graphics processing unit (GPU)-based real-time data processing pipeline for SS-OCT, achieving a measured line-process rate of 800[Formula: see text]kHz for 3D fast and high-quality data visualization. Furthermore, a GPU-based real-time data processing for CC-OCTA was integrated to acquire dynamic information. Moreover, a vascular-like network chip was prepared using extrusion-based 3D printing and sacrificial materials, with sacrificial material being printed at the desired vascular network locations and then removed to form the vascular-like network. OCTA imaging technology was used to monitor the progression of sacrificial material removal and vascular-like network formation. Therefore, GPU-based OCT enables real-time processing and visualization with artifact suppression, making it particularly suitable for in situ noninvasive longitudinal monitoring of 3D bioprinting tissue and vascular-like networks in microfluidic chips.

A transcranial multiple waves suppression method for plane wave imaging based on Radon transform

Transcranial ultrasound imaging presents a significant challenge due to the intricate interplay between ultrasound waves and the heterogeneous human skull. The skull’s presence induces distortion, refraction, multiple scattering, and reflection of ultrasound signals, thereby complicating the acquisition of high-quality images. Extracting reflections from the entire waveform is crucial yet exceedingly challenging, as intracranial reflections are often obscured by strong amplitude direct waves and multiple scattering. In this paper, a multiple wave suppression method for ultrasound plane wave imaging is proposed to mitigate the impact of skull interference. Drawing upon prior research, we developed an enhanced high-resolution linear Radon transform using the maximum entropy principle and Bayesian method, facilitating wavefield separation. We detailed the process of wave field separation in the Radon domain through simulation of a model with a high velocity layer. When plane waves emitted at any steering angles, both multiple waves and first arrival waves manifested as distinct energy points. In the brain simulation, we contrasted the characteristic differences between skull reflection and brain-internal signal in Radon domain, and demonstrated that multiples suppression method reduces side and grating lobe levels by approximately 30 dB. Finally, we executed in vitro experiments using a monkey skull to separate weak intracranial reflection signals from strong skull reflections, enhancing the contrast-to-noise ratio by 85 % compared to conventional method using full waveform. This study deeply explores the effect of multiples on effective signal separation, addresses the complexity of wavefield separation, and verifies its efficacy through imaging, thereby significantly advancing ultrasound transcranial imaging techniques.

Droplet Velocity Measurement Of Acetone-Water Spray Using Fluorescence-Based Particle Image Velocimetry

A method for measuring the velocity of liquid droplets emanating from an effervescent injector into ambient air was experimented using a mixture of acetone and water. Conventional methods such as Laser Doppler Velocimetry and Particle Image Velocimetry, which utilise Mie-scattering, have limitations due to multiple scattering and strong surface reflections, respectively. In the current study, we demonstrate fluorescence-based particle image velocimetry, which can overcome the abovementioned difficulty. Unlike previous similar studies that used fluorescent dyes, the inherent fluorescence of acetone is utilised in our strategy. The acetone and water were mixed in different volume ratios, and the effervescent jet was produced with air. The Gas-to-Liquid ratio of 8% was considered in this study. The spray droplets were excited using the fourth harmonic of the Nd-YAG laser. Two acetone Planar Laser laser-induced fluorescence images are acquired with a CCD camera and with a 20 µs time difference. The velocity vectors are obtained based on the cross-correlation between the two images. The results showed that absorption greatly influences the estimated velocity distribution. At a low acetone concentration, the velocity distribution became uniform around the jet centre line. A high-intensity laser could improve the velocity estimate in the core of the aerated jet. The proposed method can be applied directly to ambient and pressurised conditions where wall scattering is dominant. The directional independence of the fluorescence is also an advantage in scenarios where the imaging angle is a constraint.

Lightweight, Elastic, and Superhydrophobic Multifunctional Organic-Inorganic Fibrous Aerogels for Efficient Oily Wastewater Purification and Electromagnetic Microwave Absorption.

Lightweight and robust aerogels with multifunctionality are highly desirable to meet the technological demands of current society. Herein, we designed lightweight, elastic, and superhydrophobic multifunctional organic-inorganic fibrous hybrid aerogels which were assembled with organic aramid nanofibers and inorganic hierarchical porous carbon fibers. Thanks to the organic-inorganic fiber hybridization strategy, the optimal aerogels possessed remarkable compressibility and elasticity. Benefiting from the microscopic hierarchical porous structure of carbon fibers and the macroscopic macroporous lamellar structure of aerogels, the optimal aerogels exhibited superb lightweight property, conspicuous electromagnetic microwave absorption ability, and outstanding oily wastewater purification capacity. As for electromagnetic microwave absorption, it achieved a strong reflection loss of -41.8 dB, and the effective absorption bandwidth reached 6.86 GHz. Besides, the oil adsorption capacity for trichloromethane reached as high as 93.167 g g-1 with a capacity retention of 95.6% after 5 cycles. Meanwhile, it could act as a gravity-driven separation membrane to continuously separate trichloromethane from a trichloromethane-water mixture with a high flux of 7867.37 L·m-2·h-1, even for surfactant-stabilized water-in-n-heptane emulsions of 3794.94 L·m-2·h-1. Such a strategy might shed some light on the construction of multifunctional aerogels toward broader applications.

Template-sacrificing synthesis of hollow Co@C nanorods for excellent microwave absorption

Metal organic frameworks (MOFs) have been widely used as microwave absorption (MA) materials owing to their varied structures and large specific surface area. However, it is still challenging to endow MOF derivatives with a rational structure to achieve outstanding microwave absorption. In this work, the hollow Co@C nanorods (HCCN) with lots of winding carbon nanotubes on the surface are obtained based on a template-sacrificing method which employs ZnO nanorods as templates and ZIF67 nanoparticles as ornaments. The HCCNs possess large pore size and specific surface area, efficiently improving the impedance matching. The 1D structure, abundant heterointerfaces and defects trigger strong conduction loss, interfacial and dipole polarization, respectively. Therefore, HCCNs exhibits excellent MA properties: the strong reflection loss of −66.8 dB at the thickness of 2.1 mm and the effective absorption bandwidth of 5.68 GHz at 2.5 mm. Radar cross section (RCS) simulation results have confirmed the practicality of HCCNs. This study proposes an inspiration for the structural designing of MOF materials and derivatives to realize amazing MA performance.

Multi-interface spatial star-like MoC/Co/C composites toward enhanced electromagnetic wave absorption properties

Interfacial engineering and morphology design are two popular strategies to strengthen the performance of carbon-based composites as electromagnetic wave absorbing materials (EWAMs). Herein, we integrate their advantages simultaneously in ternary MoC/Co/C composites (SMCCs). On one hand, highly dispersed MoC and Co nanoparticles create abundant heterogeneous interfaces, and on the other hand, the spatial star-like carbon skeletons derived from ZnCo-MOF also bring significant structure contribution to EM energy consumption. EM measurement reveals that the pyrolysis temperature greatly impacts EM properties of SMCCs. After blending with paraffin (organic binder), the mixture that involves SMCC-800 (pyrolyzed at 800 °C) may have both good impedance matching degree and powerful EM attenuation ability. As a result, SMCC-800/paraffin displays excellent EM absorption performance, including strong reflection loss intensity down to −67.3 dB at 16.2 GHz (thickness: 1.8 mm) and broad response bandwidth of 6.0 GHz (12.0–18.0 GHz, thickness: 2.0 mm) less than −10.0 dB, which outdo the performance of many composites with similar chemical composition ever reported. The EM absorption mechanism of SMCC-800/paraffin is comprehensively illustrated through the investigation on EM properties of the mixtures with various control samples.

A modified phase-retrieval algorithm to facilitate automatic de novo macromolecular structure determination in single-wavelength anomalous diffraction.

The success of experimental phasing in macromolecular crystallography relies primarily on the accurate locations of heavy atoms bound to the target crystal. To improve the process of substructure determination, a modified phase-retrieval algorithm built on the framework of the relaxed alternating averaged reflection (RAAR) algorithm has been developed. Importantly, the proposed algorithm features a combination of the π-half phase perturbation for weak reflections and enforces the direct-method-based tangent formula for strong reflections in reciprocal space. The proposed algorithm is extensively demonstrated on a total of 100 single-wavelength anomalous diffraction (SAD) experimental datasets, comprising both protein and nucleic acid structures of different qualities. Compared with the standard RAAR algorithm, the modified phase-retrieval algorithm exhibits significantly improved effectiveness and accuracy in SAD substructure determination, highlighting the importance of additional constraints for algorithmic performance. Furthermore, the proposed algorithm can be performed without human intervention under most conditions owing to the self-adaptive property of the input parameters, thus making it convenient to be integrated into the structural determination pipeline. In conjunction with the IPCAS software suite, we demonstrated experimentally that automatic de novo structure determination is possible on the basis of our proposed algorithm.

Pressure-induced lead-free halide double perovskite [formula omitted] for optoelectronic applications

The structural, electronic, optical, mechanical and thermodynamic properties of the lead free double perovskites Rb2CuSbX6(X=Cl,Br) were investigated using first principles based on density functional theory (DFT) under pressure. Our calculated results are in good agreement with other experimental results. Electronic and optical features are pressure dependent, including dielectric effect, pressure-dependent refractive index changes, strong UV reflectivity, suggesting potential applications in solar heating reduction. Using the Voigt-Reuss-Hill approximation, an increase in stiffness, of Rb2CuSbX6(X=Cl,Br) is observed with increasing loads, revealing its stability, making it appropriate for shaping. By analyzing the formation energy and Born's stability criteria, we justified the stability to check the mechanical and thermodynamic stability of the material. In addition, the mechanical properties of Rb2CuSbX6(X=Cl,Br) conducted with the study of elastic constants, elastic moduli, machinibility index, Kleinmen parameter and Vickers hardness. Our investigation indicates that both the materials provide significant potential for very high-quality optical data using optoelectronic applications.

Asymmetrical Absorption and Surface‐Enhanced Raman Scattering Enhancement by Silver Nanoflower Metasurface

A metasurface composed of silver nanoflower arrays, which exhibit asymmetrical absorption and surface‐enhanced Raman scattering (SERS) due to hybrid plasmonic effects, is reported. The silver nanoflowers are fabricated by oblique deposition of silver on a polymer nanohole array on a glass substrate, forming petal‐like semicontinuous thin films on the inner walls of the holes. Depending on the deposition angle, three‐ or five‐petal nanoflowers are obtained. The nanoflower arrays show strong reflection from the air side and broadband and wide‐angle absorption from the glass side, as a result of transmission surface plasmon resonance and localized surface plasmon resonance, respectively. The three‐petal structure, which absorbs most of the incident light from the glass side, induces a localized enhancement of electric field in the center of each nanohole, providing a high‐sensitivity SERS substrate. The SERS performance of the metasurface by direct measurement and near‐field simulation is demonstrated.