Lattice Parameters Of Structure Research Articles

First principle calculations of structural, electronic, and optical properties of XSnO3 (X: Ca, Mg, Sr) perovskite oxides

The perovskite oxides XSnO3have garnered significant attention due to their potential applications in various fields, including electronics, photonics, and renewable energy technologies. This study presents a comprehensive theoretical investigation of the structural, electronic, and optical properties of XSnO3(X: Ca, Mg, Sr) compounds with density functional theory based on the full potential linearized augmented plane wave method. Our analysis begins with thoroughly examining the structural stability and lattice parameters of XSnO3compounds, revealing their robust perovskite crystal structures. These compounds' lattice constants, total energy, bulk modulus, and cohesive energy were determined. Subsequently, we delve into the electronic properties of XSnO3, elucidating their electronic band structures, density of states, and charge densities. The studied compounds are indirect bandgap semiconductors having band gaps in the visible range. Furthermore, our investigation extends to the optical properties of XSnO3, encompassing absorption spectra, refractive indices, energy loss function, reflectivity, extinction coefficient, and dielectric functions across a wide range of wavelengths. Overall, the excellent optical properties of these compounds make them suitable for optoelectronic applications.

Identification for elastoplastic constitutive parameters of 316L stainless steel lattice structures using finite element model updating and integrated digital image correlation

Identification for elastoplastic constitutive parameters of 316L stainless steel lattice structures using finite element model updating and integrated digital image correlation

Mn-Rich Induced Alteration on Band Gap and Cycling Stability Properties of LiMnxFe1-xPO4 Cathode Materials.

Olivine-type LiMnxFe1-xPO4 (LMFP) has inherited the excellent heat-stable structure of LiFePO4 (LFP) and the high-voltage property of LiMnPO4 (LMP), which shows great promise as a high-safety, high-energy-density cathode material. In order to combine the high energy density and excellent electrochemical performance, it is essential to consider the Mn/Fe ratio. This paper presents a theoretical investigation of the lattice structure parameters, embedded lithium voltage, local electron density, migration barrier, and lithium ion delithiation and lithiation mechanism of different LiMnxFe1-xPO4 (0.5 ≤ x ≤ 0.8) compounds. In situ-coated LiMnxFe1-xPO4 (0.5 ≤ x ≤ 0.8) composite cathode materials with a size of 100-200 nm were prepared by a hydrothermal method to verify the theoretical study. LiMn0.6Fe0.4PO4/C exhibited a specific capacity of 140.2 and 97.58 mA h·g-1 at 1 and 5C, respectively, and a remarkable capacity retention rate of 88.5% after 200 cycles at 1C. When LiMn0.6Fe0.4PO4/C was assembled into a flexible pouch battery and subjected to long cycle tests at different rates and squeeze and extrusion tests, it demonstrated a capacity retention rate of 99.35% for 100 cycles at 0.2C and 93.2% for 200 cycles at 0.5C. Moreover, the structural evolution of LiMn0.6Fe0.4PO4/C were analyzed in situ XRD, indicating a high stability and the resulted as obtine electrochemical performance, paving the way for optimization of high-energy-density LMFP cathode materials.

An improved BCC lattice structure for vibration isolation in extreme environment

A new improved body-centered cubic (BCC) lattice structure is proposed to improve the load capacity by adding a body-centered ball to reduce stress concentrations. The new lattice structure, named as body-centered cubic with balls (BCC-B) lattice structure, is characterized by lightweight, compactness, large load capacity, radiation resistance, and corrosion resistance, which can be widely used for vibration isolation in various areas such as ships, aerospace, nuclear facility, and so on. Theoretical model of BCC-B lattice structure is established. The influences of structure parameters of BCC-B lattice structure are analyzed by both theoretical and numerical methods. Both BCC and BCC-B lattice structure samples are prepared by using Ti-6Al-4V, of which the stiffness, rated load capacity, and yield strength are tested and compared detailly. Compared with the BCC lattice structure, the BCC-B lattice structure shows a 31.58% increase in rated load capacity, a 10.15% decrease in natural frequency, and a 29.53% increase in yield strength. This study might provide some insights for the development of vibration isolators with large load and low stiffness for applications in extreme environmental conditions such as limited space, nuclear radiation, and high temperatures in future.

Exploring energy harvesting potential of lithium-based halide perovskites Li2CuSbZ6 (Z=Cl, Br): First principles approach

Recent research has focused on investigating the physical characteristics of the halide perovskite combinations, Li2CuSbZ6 (Z = Cl, Br) within the context of Density Functional Theory (DFT). The optimized FCC cubic structure lattice parameters for Li2CuSbCl6 and Li2CuSbBr6 are 10.57 and 11.10 Å, respectively. We have examined the stability by evaluating the tolerance factor, formation energy, and the Born Criteria. The analysis conducted on the elastic constants identifies the ductility, anisotropy, melting, and Debye temperatures. First-principles calculations reveal that computed electronic features using the TB-mBJ approximation unveiled an indirect band gap of 1.33 and 1.04 eV, respectively. Optical analyses indicate that the studied halide perovskites exhibits significant absorption in the visible and ultraviolet regions. Boltzmann's classical theory explains the transport features and attained higher figure of merit (ZT) values for both perovskites. These research findings provide a significant potential for these materials in the absorber layer of perovskite-based solar cells as well as thermoelectric devices.

Enhanced cyclability and energy density of mid-nickel layered oxide cathode material LiNi0.55Mn0.25Co0.20O2 by niobium doping via solvothermal method

Ni-based layered oxide materials are among the most promising cathode materials for the next generation of lithium-ion batteries due to their higher energy capacity. However, capacity decay occurs due to degradation mechanisms that reduce the electrochemical performance of this type of material. This work aims to synthesize Nb-doped LiNi0.55Mn0.25Co0.20O2 (Nb-NCM) materials via the solvothermal method to enhance the cyclability and energy density of the layered oxide cathode. The effects of Nb doping on the microstructure and the electrochemical performance of the cathodes are investigated. The introduction of the contents of Nb expands the structural lattice parameters and decreases the Li+/Ni2+ cation mixing degree of the NCM cathode. Furthermore, the Nb doping enhances the electrochemical activity of LiNi0.55Mn0.25Co0.20O2, increasing its initial discharge capacity to 169.61 mAhg−1 when 1% of Nb was used as a dopant (1%Nb-NCM) in contrast to the capacity of 149.45 mAhg−1 presented by the pristine material. The modified 1.0%Nb-NCM material also exhibits remarkable cycling performance with a capacity retention of 92.7% after 100 cycles at the rate of 1 C (2.8–4.3 V). This work suggests a rational strategy for high-performance cathode for lithium-ion batteries, proposing the extension of Nb doping to enhance Ni-mid material's cyclability.

Microstructural evolution and magnetic influence mechanism of Cr in-situ alloying SLM-formed NiFeMo alloys

NiFeMo is prevalently employed in the field of aerospace and electronic devices owing to its excellent soft magnetic properties. Besides, the incorporation of elements through in-situ alloying presents a novel strategy for performance modulation in Selective Laser Melting (SLM), presenting a novel pathway toward the advancement of soft magnetic materials. In this study, (NiFeMo)100-xCrx alloys (x=0 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%) were prepared utilizing Cr in-situ alloying SLM. The magnetic properties as well as microstructural characterization were conducted by employing X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), high-resolution transmission electron microscopy (HRTEM) (Tecnai-G2-F30), and direct current B-H hysteresis curve testing equipment (MATS-2010S). The results indicate that the microstructure of the SLM-formed NiFeMo alloy through in-situ chromium alloying is predominantly characterized by columnar grains growing along the build direction. With an increase in the in-situ alloying ratio of chromium, the lattice parameters of the FCC phase structure of the NiFeMo alloy decrease from 3.582 Å to 3.503 Å, the average grain size monotonically decreases, and the maximum texture strength monotonically weakens. Furthermore, during the in-situ alloying SLM process, chromium is dissolved into the FCC γ-(Ni, Fe) of the NiFeMo alloy, forming dispersed, chromium-rich precipitates of larger sizes. This leads to a reduction in the intrinsic magnetic properties of the NiFeMo alloy, affecting the exchange coupling interaction between magnetic atoms and the motion of magnetic domains. Compared to the NiFeMo alloy, the saturation magnetization of the (NiFeMo)97.5Cr2.5 alloy is reduced to 0.4685 T, and the coercive force is increased to 37.7 A/m. However, when the chromium content is 1 wt%, the initial magnetic permeability of the (NiFeMo)99Cr1 alloy is 2.337 mH/m, which is an enhancement of 1.9422 mH/m compared to the NiFeMo alloy.

Mitigation effects of lattice structure arrays on heat transfer deterioration of supercritical CO2

This study numerically investigates the suppression mechanism of heat transfer deterioration (HTD) of supercritical carbon dioxide (SCO2) in heated vertical channels with lattice structure arrays (LSA). The influences of lattice structure parameters on the velocity field, temperature field, heat transfer coefficient, buoyancy effect and flow acceleration effect are analyzed. The results demonstrate that compared to smooth channels, the tri-claw LSA can significantly reduce the maximum peak wall temperature by up to 57 K. The heat transfer coefficient substantially increases, and the fluid turbulent kinetic energy (TKE) quintuples. The vortex structures generated by lattice structures can enhance turbulence intensity and heat transfer, which effectively mitigates buoyancy effect and ultimately suppresses HTD. Increasing the lattice claws number can create more complex vortex structures, lengthening the lattice disrupts the laminar flow within the boundary layer, increasing the lattice diameter can produce a composite vortex that enhances the strength of flow mixing. An increase lattice number across the cross-section strengthens the suppression effect, but an excessive number may lead to instability. A dense lattice arrangement can continually suppress HTD, achieving an overall improvement in heat transfer within a certain range. This paper could support the design of heat exchangers in SCO2 Brayton cycles.

A novel design method based onmulti–objective optimization for graded lattice structure by additive manufacturing

PurposeWhile performance demands in the natural world are varied, graded lattice structures reveal distinctive mechanical properties with tremendous engineering application potential. For biomechanical functions where mechanical qualities are required from supporting under external loading and permeability is crucial which affects bone tissue engineering, the geometric design in lattice structure for bone scaffolds in loading-bearing applications is necessary. However, when tweaking structural traits, these two factors frequently clash. For graded lattice structures, this study aims to develop a design-optimization strategy to attain improved attributes across different domains.Design/methodology/approachTo handle diverse stress states, parametric modeling is used to produce strut-based lattice structures with spatially varied densities. The tailored initial gradients in lattice structure are subject to automatic property evaluation procedure that hinges on finite element method and computational fluid dynamics simulations. The geometric parameters of lattice structures with numerous objectives are then optimized using an iterative optimization process based on a non-dominated genetic algorithm.FindingsThe initial stress-based design of graded lattice structure with spatially variable densities is generated based on the stress conditions. The results from subsequent dual-objective optimization show a series of topologies with gradually improved trade-offs between mechanical properties and permeability.Originality/valueIn this study, a novel structural design-optimization methodology is proposed for mathematically optimizing strut-based graded lattice structures to achieve enhanced performance in multiple domains.

Optimization of radiation shielding efficacy through tuning the crystal lattice parameters: Case study of α-quartz

Crystal γ-ray radiation competence on α-quartz crystal up to 15 GPa pressure unveil structural-shielding properties coupling. With increasing pressure the average lattice axial length known as a, and b are decreased affecting the behavior of the observed LAC or HVL values. Via tuning the lattice parameters (4.914<a<4.470 Å) and unit cell volume (113.06<Vc < 89.10 Å3), we were able to optimize the α-quartz crystal shielding performance via adjusting the essential shielding parameters (i.e., (5.809<MAC<0.021 cm2/g), (3.10 × 1023<Neff< 3.74 × 1023 e/g), (10.32<Zeff<12.43), and (10.79<Zeq<11.56)). We find that the maximum value of LAC = 16.61 cm−1 occur at defined unitcell parameters (a = 4.535 Å, c = 5.170 Å c/a = 1.14419, and Vc = 92.09 Å3). Whereas, the LAC minimum value is 12.67246 cm−1 at a = 4.90232 Å, c = 5.38309 Å, c/a = 1.10149, and Vc = 110.91621 Å3). The same is applied on the HVL behavior. This report, confirmed that changing the crystal structural lattice parameters allows for a different chances between the incident radiation-unit cell interactions for a possible optimization against the γ-rays penetrations into the crystal's sub-structures.

Optimizing implant lattice design for large distal femur defects: Stimulating interface bone growth to enhance osseointegration

Large bone defects in the distal femur present a significant challenge due to the lack of inherent self-healing capabilities. Traditional approaches, such as utilizing polymethyl methacrylate (PMMA) in conjunction with a plate for distal femur reconstruction, have shown unsatisfactory osseointegration outcome, which leads to complications. To address this challenge, this study focuses on developing a lattice-structured implant for reconstructing distal femoral bone defects. The lattice geometry is based on the cuboctahedron lattice, with its design optimized through the adjustment of pillar diameter and arrangement angle. The lattice structure is designed to stimulate the surrounding bone, ultimately enhancing osseointegration in distal femur reconstruction. Finite element analysis revealed that for promoting bone ingrowth toward the implant, setting the optimal lattice structure parameters, i.e., a 45&amp;deg; arrangement angle and a 0.8 mm pillar diameter, is required. Fabricated using state-of-the-art metal three-dimensional printing, the implant underwent rigorous validation through biomechanical testing, in vitro biological assays, and animal experiments. The comprehensive results affirmed the bioactivity of the lattice-structured implant, underscoring its capability to improve osseointegration in distal femoral defect reconstruction.

Synthesis and characterization of Magnetic Fe3O4/SiO2 composite for Environmental Sanitation

The synthesis and characterization of the Fe3O4/SiO2 composite using the co-precipitation method have been conducted. Magnetite (Fe3O4) possesses magnetic properties capable of removing catalyst and dye waste. Silica is excellently suited as a material for magnetic coatings. The Fe3O4/SiO2 composite was characterized using XRD to identify the crystal phase and lattice structure parameters. Morphological analysis and elemental mapping of the sample were carried out using SEM-EDS, and FTIR was used to identify the functional groups. The XRD characterization results show that the Fe3O4/SiO2 composite crystallizes well, with identified peaks at angles of 2θ = 30.18°; 36.86°; 43.14°; 53.52°; 57.08°. The FTIR test results indicate the presence of SI-O-Si bonds, characteristic of the SiO2 peak, and Fe-O bonds, which are indicative of Fe3O4. The homogeneous morphologies are demonstrated by the SEM-EDS image.

Effects of TiC0.4 and Ti addition on the microstructures and mechanical properties of TiC composites

TiC-14 wt%TiC0.4 and TiC-7.63 wt%Ti ceramics were fabricated by spark plasma sintering (SPS) at a sintering temperature of 1600 °C and an applied pressure of 40 MPa. The impact of ex-situ addition and in-situ formation of vacancies on the microstructures and mechanical properties of TiC composites were investigated. The microstructures were analysed by XRD, SEM, EDS and TEM. The results reveal that TiC1-x phases with different Ti/C ratios exist in the TiC-14 wt%TiC0.4 ceramics, which have the same crystal structure and similar lattice parameters. In contrast, only a single phase of TiC1-y exists in the TiC-7.63 wt%Ti ceramics. The introduced carbon vacancies not only lowered the sintering temperature, but also had a toughening effect on the material. At a sintering temperature of 1600 °C, the TiC-14 wt%TiC0.4 and TiC-7.63 wt%Ti materials had densities of 98.5% and 99.2%, both materials exhibited excellent mechanical properties Vickers hardness and fracture toughness of 22.5 GPa, 5.2 MPa m1/2 and 23.5 GPa, 4.9 MPa m1/2, respectively.

Composite anisogrid lattice toroidal shell: Application to a load-carrying rim of the spacecraft reflectarray antenna

A novel design of the composite transformable/foldable rim of the spacecraft reflectarray antenna is presented in the paper. The rim is made in the form of anisogrid lattice toroidal shell split into six parts that are jointed using hinges containing helical springs. The springs create the moments required to deploy the antenna in orbit. A dielectric flexible flat membrane with reflective radiating elements generating a radio signal with required directivity is stretched on the rim. An algorithm of the finite-element model generation is developed for the toroidal rim using a typical finite-element unit cell of lattice structure. The lattice toroidal shell is modelled as a three-dimensional frame composed of curvilinear ribs. The results of design analysis of the lattice rim delivering a minimal mass to its structure subject to constraints imposed on the fundamental frequency, values of stress, and the buckling load factor are presented in this work. The corresponding set of design parameters of lattice structure, including the angle of orientation of helical ribs, number of helical ribs of one orientation, and size of the ribs’ cross section are identified based on these results.

Design of 3D printed pressure-reducing insoles based on changes in parameters of lattice structure

Uneven distribution of pressure on the bottom of the foot or excessive local pressure shall cause discomfort. And when it gets severe, this pressure would even damage the health of the human foot, especially for people like the elderly, diabetic patients and pregnant women. Decompression footwear can effectively reduce pressure on the foot and reduce the risk of injury. However, mass-produced pressure-reducing footwear lacks pertinence due to individual differences in human plantar pressure and foot shape data. This paper presents a design, using gradient lattice structures, for four kinds of 3D printed pressure-reducing insoles. It turns out that full contact insoles with non-uniform distribution of lattice structure did the best in reducing peak pressure of the whole foot, which was 60.42% lower than that of bare foot, 17.24% of flat insole with uniform distribution of lattice structure, 13.68% of mass-produced pressure-reducing footwear. The effect on pressure reduction is significant.

Multi-objective Optimization for the Base Lattice Structure of a Small Space Sampling Return Capsule

The space sample-return mission capsule will bear a large landing impact at the moment of landing, so the return capsule structure is required to be the lightest under the premise of ensuring the safety of equipment and sampling samples. In view of the small size, compact layout and high lightweight requirements of the space sample-return mission module, the base lattice structure made of additive materials can achieve better comprehensive performance of landing impact resistance. In this paper, design of experiments (DOE) and surrogate model are used to carry out parameter sensitivity analysis and multi-objective optimization for the base lattice structure of small return capsule landing impact for space sampling. First, the parametric model of the large base lattice of the landing impact dynamics of the return capsule was established. Then, the Latin Hypercube Sampling (LHS) method was used to carry out sensitivity analysis of the lattice structure parameters and identify key factors. Finally, the response surface model was constructed, and the genetic algorithm was used to optimize the lattice structure parameters. The optimal design was obtained. By comparison with the dynamics analysis model, the results of the surrogate model are basically consistent with the dynamic analysis results.

Oxidation of Zinc Microparticles by Microwave Plasma to Form Effective Solar-Sensitive Photocatalysts

The presented work studies the processes of synthesis of ZnO microstructures using atmospheric-pressure microwave nitrogen plasma and investigates their photocatalytic activity in the processes of degradation of 2,4-dinitrophenol and the antibiotic ciprofloxacin when irradiated with sunlight. The work proposes an effective method for formation of photosensitive ZnO powders. Due to the features of plasma treatment in the open atmosphere of zinc metal microparticles, ZnO structures are formed with sizes from hundreds of nanometers to several micrometers with various micromorphologies. The lattice parameters of ZnO structures are characteristic of a hexagonal unit with a = 3.258 Å and c = 5.21 Å, volume 47.95 Å3. The size of the crystallites is 48 nm. The plasma treatment was performed by means of a 2.45-GHz plasmatron at a power input of 1 kW in nitrogen flow at a rate of 1–10 L/min. Zn microparticles were injected into the microwave plasma at a mass rate of 20 g/min. High photoactivity was demonstrated (rate constants 0.036 min−1 and 0.051 min−1) of synthesized ZnO structures during photo-degradation of 2,4-dinitrophenol and ciprofloxacin, respectively, when exposed to solar radiation. Photo-active structures of ZnO synthesized using microwave plasma can find application in processes of mineralization of toxic organic compounds. Structures of ZnO synthesized using microwave plasma can find application in processes of mineralization of toxic organic compounds, and also in scintillation detectors, phosphors.

Multi-objective optimization of additive manufactured functionally graded lattice structures under impact

A multi-objective optimization procedure to effectively design gradient lattice structures under dynamic loading is presented. It aims both at maximized energy absorption characteristics and a lightweight design. The reduction of the peak crushing force and a maximized specific energy absorption are simultaneously optimized. Design variables like the relative density and density gradient of the lattice structure are investigated, considering different topologies of the lattice unit cells. To model and simulate the lattice structures efficiently, a simplified beam-based simulation finite element model is introduced and validated against experimental tests. They cover the range from dynamic equilibrium up to compaction wave propagation as impact deformation phenomena. Based on large numbers of simulations, an artificial neural network is used to predict the energy absorbing characteristics for the given design parameters and to find the optimal configuration of the lattice structures. The neural network is trained using a multi response adaptive sampling algorithm allowing parallel simulation with automatically generated finite element models during each iteration step. Subsequently, a multi-objective genetic algorithm is used to find optimal combinations of the design parameters of lattice structures under different impact velocities and cell topologies.

Investigation on the synthesis, growth, thermal and optical behavior of creatininium borate single crystal: A potential candidate for nonlinear optical applications

In the this study, we focus on the growth of a metal-organic creatininium borate (CRB) single crystal for third-order nonlinear optical (NLO) applications. Optically transparent &amp; wide optical band gap single crystals of CRB were successfully harvested by adopting a slow evaporation solution technique (SEST) at a constant 40[Formula: see text]C temperature. The structural identification and lattice parameters of the grown sample were determined by powder X-ray diffraction (PXRD) using Rietveld analysis by FullProf Suite software. The occurrence of vacancy/interstitial defects produced during growth was investigated by high-resolution X-ray diffraction (HRXRD) using omega scan arrangement. A single peak with lower full width half maxima (56.4 arc s) was obtained from the scan which suggests that there were no grain boundaries for the grown crystal. Surface morphology and its features such as concentration of dislocations and defect sites on the as-grown sample were scrutinized using the etching technique. The optical band gap and UV–vis cut-off were examined and found to be 5.39 eV and 230 nm, respectively. Photoluminescence characteristics of the crystal show an emission at 377 nm upon excitation with a wavelength of 336 nm. The presence of radiative and non-radiative transitions inside the crystal due to excitation upon 266 nm laser was identified using time-resolved photoluminescence. Thermal stability and decomposition temperature of the compound were obtained by thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The third-order nonlinearity of the crystal was determined by Z-scan measurement technique with a femtosecond Ti-sapphire laser.

Rationality of two-phase coexistence with no element segregation in a CuZr-based amorphous alloy composite

Here, the structure features of Cu62Zr34.4Al3Nb0.6 amorphous alloy composites (AACs) are studied by combining experimental characterization with first-principles calculation. Element segregation, which is common in conventional alloy materials, does not occur in two phases (crystalline and amorphous phase) of the AACs due to complex solid solution. The lattice parameters, electron distribution, charge transfer and electrical potential, which are directly related to atomic bonding and lattice parameters of different structures, are obtained by calculating the various types of structural models, including interstitial solid solution, substitutional solid solution, B2 and amorphous phase. Finally, the formation and stability of solid solution in crystalline phase and amorphous phase are elucidated by first-principles calculation. The work has important guiding significance for understanding the two-phase structure and solidification mechanism in AACs materials.