Planar Triangles Research Articles

Accelerating Li-Ion Diffusion in LiFePO4 by Polyanion Lattice Engineering.

Despite the widespread commercialization of LiFePO4 as cathodes in lithium-ion batteries, the rigid 1D Li-ion diffusion channel along the [010] direction strongly limits its fast charge and discharge performance. Herein, lattice engineering is developed by the planar triangle BO3 3- substitution on tetrahedron PO4 3- to induce flexibility in the Li-ion diffusion channels, which are broadened simultaneously. The planar structure of BO3 3- may further provide additional paths between the channels. With these synergetic contributions, LiFe(PO4)0.98(BO3)0.02 shows the best performance, which delivers the high-rate capacity (66.8 mAhg-1 at 50 C) and long cycle stability (ultra-low capacity loss of 0.003% every cycle at 10 C) at 25°C. Furthermore, excellent rate performance (34.0 mAhg-1 at 40 C) and capacity retention (no capacity loss after 2500 cycles at 10 C) at -20°C are realized.

Role of CsBr in structure and properties of new cesium bromo-borate glasses

Glasses of enlarged chemical composition in the xCsBr-(100-x)B2O3 system, with x = 30–80 mol% have been prepared and studied for the first time. The hydrothermal preparation method is used to prepare fine powdered samples. The X-ray Diffraction (XRD), Fourier Transform Infrared spectra (FTIR) and 11B Nuclear Magnetic Resonance (11B NMR) are the tools used to study the structure of glasses. Even at the high CsBr concentration (30–60 mol%), XRD results revealed an amorphous structure characterized most of the examined compositions. But glasses enriched with CsBr (70 and 80 mol%) possess some ordered sub-structures impeded in the main amorphous network. 11B NMR and FTIR spectroscopy confirmed the presence of BO3 triangle as the major and dominant structural units. The four coordinated boron (BO4), on the other hand, can't be detected in the all analyzed compositions. An extremely low concentration from BBr4 tetrahedral groups (boron coupled with Br) is formed. The B-O bonds of planar BO3 triangles, which are the fundamental units, were involved in the production of amorphous clusters of the type Cs4B5O9]Br. Density (D) measurement and calculating molar volume (Vm), packing density and free volume(Vf) have been studied. The added CsBr can't play a role of modifier but it might be inserted interstitially between the borate structural units causing increasing of molar volume and free space in the glass network structure. The results based on transmission electron microscopy (TEM-EDP) and X-ray diffraction pattern (XRD) are in good agreement, indicating that the amorphous-clustered species are developed in the studied glasses.

Fast phase matching based on order partition with sub-pixel accuracy

Structured light is a method of 3D imaging that involves projecting a sequence of striped or structured patterns onto a target scene and then, based on the warping of stripes across a target surface, a camera can reconstruct the target. For practical reasons relating to changing lens parameters for the projector, binocular structured light improves over monocular structured by performing triangulation between two cameras, using the striped patterns to solve the correspondence matching problem; however, the speed at which these correspondences are found is still an active area of research. And in this paper, we propose a fast-matching algorithm that enhances phase labeling and introduces the concept of triangle plane interpolation based on linear interpolation. The experimental results demonstrate that our method achieves a noticeable speed improvement in computational efficiency and a stable improvement in accuracy as compared to the phase matching along epipolar line pointwisely based on look-up tables.

Near Ultraviolet‐Excitable Cyan‐Emissive Hybrid Copper(I) Halides Nonlinear Optical Crystals with Near‐Unity Photoluminescence Quantum Yield and High‐Efficiency X‐ray Scintillation

AbstractDesigning and synthesizing multifunctional hybrid copper halides with near ultraviolet (NUV) light‐excited high‐energy emission (<500 nm) remains challenging. Here, a pair of broadband‐excited high‐energy emitting isomers, namely, α‐/β‐(MePh3P)2CuI3 (MePh3P=methyltriphenylphosphonium), were synthesized. α‐(MePh3P)2CuI3 with blue emission peaking at 475 nm is firstly discovered wherein its structure contains regular [CuI3]2− triangles and crystallizes in centrosymmetric space group P21/c. While β‐(MePh3P)2CuI3 featuring distorted [CuI3]2− planar triangles shows inversion symmetry breaking and crystallizes in the noncentrosymmetric space group P21, which exhibits cyan emission peaking at 495 nm with prominent near‐unity photoluminescence quantum yield and the excitation band ranging from 200 to 450 nm. Intriguingly, β‐(MePh3P)2CuI3 exhibits phase‐matchable second‐harmonic generation response of 0.54×KDP and a suitable birefringence of 0.06@1064 nm. Furthermore, β‐(MePh3P)2CuI3 also can be excited by X‐ray radioluminescence with a high scintillation light yield of 16193 photon/MeV and an ultra‐low detection limit of 47.97 nGy/s, which is only 0.87 % of the standard medical diagnosis (5.5 μGy/s). This work not only promotes the development of solid‐state lighting, laser frequency conversion and X‐ray imaging, but also provides a reference for constructing multifunctional hybrid metal halides.

Finite-element-based cross-section analysis method for functionally graded sandwich members with arbitrary shapes and gradients

Recent advancements in manufacturing technologies have facilitated the efficient and cost-effective production of functionally graded (FG) sandwich members, offering exceptional structural performances. However, designing these members is challenging due to the difficulties in accurately determining their cross-sectional properties, especially within routine designs that rely on beam-column elements. To this end, this paper introduces a robust finite-element-based cross-section analysis method for FG sandwich sections considering arbitrary shapes and material gradients. A novel nonhomogeneous plane triangle (NPT) element is formulated to enhance the computational efficiency of the developed cross-section analysis approach. A new structural analysis software with a graphic user interface, namely MSASect2, is developed based on the proposed cross-section analysis approach for its convenient implementation in practice. Four examples are displayed to verify the correctness of the present study and MSASect2, indicating their potential to promote the broader application of FG sandwich sections.

Near Ultraviolet-Excitable Cyan-Emissive Hybrid Copper(I) Halides Nonlinear Optical Crystals with Near-Unity Photoluminescence Quantum Yield and High-Efficiency X-ray Scintillation.

Designing and synthesizing multifunctional hybrid copper halides with near ultraviolet (NUV) light-excited high-energy emission (<500 nm) remains challenging. Here, a pair of broadband-excited high-energy emitting isomers, namely, α-/β-(MePh3P)2CuI3 (MePh3P=methyltriphenylphosphonium), were synthesized. α-(MePh3P)2CuI3 with blue emission peaking at 475 nm is firstly discovered wherein its structure contains regular [CuI3]2- triangles and crystallizes in centrosymmetric space group P21/c. While β-(MePh3P)2CuI3 featuring distorted [CuI3]2- planar triangles shows inversion symmetry breaking and crystallizes in the noncentrosymmetric space group P21, which exhibits cyan emission peaking at 495 nm with prominent near-unity photoluminescence quantum yield and the excitation band ranging from 200 to 450 nm. Intriguingly, β-(MePh3P)2CuI3 exhibits phase-matchable second-harmonic generation response of 0.54×KDP and a suitable birefringence of 0.06@1064 nm. Furthermore, β-(MePh3P)2CuI3 also can be excited by X-ray radioluminescence with a high scintillation light yield of 16193 photon/MeV and an ultra-low detection limit of 47.97 nGy/s, which is only 0.87 % of the standard medical diagnosis (5.5 μGy/s). This work not only promotes the development of solid-state lighting, laser frequency conversion and X-ray imaging, but also provides a reference for constructing multifunctional hybrid metal halides.

Line finite element method for geometrically nonlinear analysis of functionally graded members accounting for twisting effects

Functionally graded materials with spatially varying properties have gained widespread use in various engineering disciplines due to their exceptional mechanical characteristics. Nevertheless, these materials can lead to non-symmetric properties of cross-sections and an offset between centroid and shear center of functionally graded (FG) members, thereby significantly affecting the mechanical behavior. This phenomenon, known as twisting effects, poses a substantial challenge for the geometrically nonlinear analysis of FG members, as existing methods rely on traditional line elements that assume the centroid and shear center of the section coincide. Thus, this paper proposes a new framework for geometrically nonlinear analysis of FG members, incorporating twisting effects through a novel Timoshenko line element. An efficient finite-element-based approach that employs the nonhomogeneous plane triangle (NPT) element for calculating the cross-sectional properties of arbitrary FG cross-sections is presented. These cross-sectional properties are then utilized within the advanced line-element formulation to perform geometrically nonlinear analysis of FG structures considering twisting effects. The accuracy of the proposed method is validated through three examples, followed by several case studies to examine the impact of twisting effects on FG members. Furthermore, the proposed cross-section analysis method is integrated into a new structural analysis software MSASect2 to facilitate its application.

Zhonghongite, Cu29 (As, Sb)12S33, a new mineral from the high-sulfidation vein of Jiama porphyry system, Tibet, China

Abstract Zhonghongite (IMA2023-046), ideally Cu29(As, Sb)12S33, is a new mineral discovered in the high-sulfidation vein of the Jiama deposit (E 91°45′, N 29°42′), southern Tibet, China. It forms complex intergrowths with watanabeite and tennantite-tetrahedrite, creating veined or massive aggregates ranging from millimeters to centimeters in size. The single crystals of zhonghongite are anhedral grains, with sizes ranging from several micrometers to approximately 100 micrometers. The mineral is gray in color with a black streak and metallic luster. It is brittle, with uneven fractures, and has a calculated density of 4.925g/cm3. The average values of electron microprobe analyses (wt.%) are as follow: Cu 42.19, As 11.11, Sb 16.09, S 25.45, Hg 3.73, Mn 0.67, and Te 0.28. The empirical formula, based on 33 sulfur apfu, is (Cu27.60Hg0.77Mn0.51Fe0.07Ag0.02)Σ28.97(As6.16Sb5.49Te0.09)Σ11.74S33. In zhonghongite, the substitution of Sb for As is limited, with the atomic ratio of As/(As+Sb) ranging from 0.457 to 0.629. Hg, Mn, and Fe, together with minor Cu, are divalent and serve for charge balance. Zhonghongite is orthorhombic, space group F2mm (42), a = 10.37741(5) Å, b = 14.69821(9) Å, c = 36.7645(2) Å and V = 5607.66(5) Å3. The crystal structure has been solved and refined by single-crystal X-ray diffraction with a final R1 = 0.0235 for 27028 (2467 unique) reflections. It is composed of individual AsS3 tripyramids and clustered tripyramids As4S7, CuS4 tetrahedra and CuS3 planar triangles, connected through corner S atoms in tetrahedral coordination and octahedral coordination with Cu and/or As. The structure is a derivative of tetrahedrite-type structure. Zhonghongite was formed under high-temperature conditions and is classified as an intermediate-sulfidation state mineral.

The tunneling splittings of the ground state and some excited vibrational states for the inversion motion in H3C− anion and H3Si[rad] radical

Splitting of the ground state and some excited symmetric bending vibrational states due to inversion tunneling in the H3C− anion and H3Si radical is analyzed by numerically solving the vibrational Schrödinger equation of restricted (2D) dimensionality. We used the following two vibrational coordinates for the H3X structure (X = C, Si): the distance of the X atom from the plane of a regular triangle formed by three hydrogen atoms (1) and a symmetry coordinate composed of three distances between chemically non-bonded hydrogen atoms (2). The kinetic energy operator in this case takes the simplest form. The 2D potential energy surface (PES) in the given coordinates was calculated for H3C− at the CCSD(T)/aug-cc-pVTZ, CCSD(T)/aug-cc-pVQZ, CCSD(T)/aug-cc-pV5Z, CCSD(T)/CBS(TQ5), CCSD(T)/d-aug-cc-pVTZ, CCSD(T)/t-aug-cc-pVTZ, and CCSD(T)/q-aug-cc-pVTZ levels of theory, based on recommendations from recently published work [M.C. Bowman, B. Zhang, W.J. Morgan, H.F. Schaefer III, Mol.Phys., 117 (2019) 1069–1077]. The same 2D PES for the H3Si radical was calculated at the CCSD(T)/aug-cc-pVDZ CCSD(T)/aug-cc-pVTZ, CCSD(T)/aug-cc-pVQZ, and CCSD(T)/CBS(D,T,Q) as well as at the CCSD(T)/d-aug-cc-pVTZ, CCSD(T)/un-aug-cc-pVTZ, CCSD(T)/un-aug-cc-pVQZ levels of theory. The tunneling splittings for the D3C− anion and D3Si radical were calculated as well. The results of calculations demonstrate good agreement with available experimental data on umbrella vibration frequencies and inversion splittings for the title molecules.

Mode-shape magnification in high-speed camera measurements

If motion, identified using image-based methods, is too small to be seen with the naked eye, motion magnification can be used to help with the visualization. Established motion-magnification methods magnify (typically up to 1000 times) the band-passed content of the image data. Especially at higher frequencies, the amplitudes of measured displacements are often below the noise floor. In this research, a novel method for amplifying vibrations, based on experimental modal analysis (EMA), is introduced. The response of the examined structure to dynamic excitation is measured with a simplified, gradient-based, optical flow method and used to perform a hybrid modal analysis in conjunction with a reference accelerometer response measurement. Such a hybrid approach can: (a) identify structural dynamics significantly in the sub-pixel range, and (b) significantly below the image noise floor. The image of the vibrating structure is subdivided using a planar triangle mesh, which is then warped in accordance with the identified mode shape. A mesh-element-wise affine transformation is performed to obtain an image of the magnified mode shape. In the experimental part, the proposed method achieved magnification factors of approximately 40 thousand times, which is an order of magnitude deeper into noise than available before; additionally, the proposed approach is numerically significantly less demanding.The introduced mode-shape magnification presents an alternative to existing motion-magnification methods for applications where the harmonic displacement information is hidden by image noise.

On Heron’s Formula for the Area of a Plane Triangle

Summary This paper provides a review of proofs of Heron’s formula for the area of a plane triangle. We groups proofs together into analogy/experimental evidence, geometry (incircle radius multiplied by semi-perimeter), algebra (equivalence with the Pythagorean Theorem), trigonometric proofs (often via the cosine rule), and specialization from a more general theorem. Lastly, we discuss a neglected paper by Baker of 1885 that lists 110 distinct formulae for the area of a plane triangle and relate some of these formulae to those used in proving Heron’s formula.

The effect of iodine on the local environment of network‐forming elements in aluminoborosilicate glasses: An NMR study

AbstractKnowledge of the structural organization of nuclear waste glasses at the atomic scale is the basis for further studies of macroscopic properties (e.g., fracture toughness, chemical durability, and leaching rate). Recent studies have focused on the iodine dissolution mechanism in oxide‐based glasses synthesized under high‐pressure conditions, but there is still a lack of key information on the extent of the modifications caused by iodine entering the glass network. We therefore decided to conduct an in‐depth study by nuclear magnetic resonance on two series of aluminoborosilicate glasses synthetized under high pressure conditions and doped with either I2 or I2O5. The obtained 11B, 23Na, and 27Al nuclear magnetic resonance (NMR) spectra were fitted and correlated with the iodine content in order to find possible relationships with the local environment change for the probed cations. These data showed that iodine has no effect on the coordination of aluminum and very little effects on that of boron. In contrast, we found an expected relationship of the I content with the 23Na NMR parameters. In comparison with previous studies on the non‐bridging oxygen (NBO) distribution in aluminoborosilicate, we suggest that Na+ is mainly scavenged from silica tetrahedra with one or two NBO ( or ) as no boron planar triangles with one NBO are expected for such compositions. From those information, we establish a model for iodine dissolution in nuclear waste glass that is consistent with previous studies.

Synthesis, crystal structure and luminescent properties of a quinary borate-phosphate compound CsNa2Dy2(BO3)(PO4)2

Abstract Borate-phosphates exhibit a wide range of compositional and structural diversity, making them ideal hosts for luminescent materials. In this work, a new borate-phosphate compound CsNa2Dy2(BO3)(PO4)2 has been prepared under high temperature solution growth method. It crystallizes in an orthorhombic space group Cmcm with the following lattice parameters determined by single-crystal X-ray diffraction: a = 6.9709(5), b = 14.9699(11), c = 10.6480(8) Å, z = 4. Its structure contains isolated BO3 planar triangles and PO4 tetrahedra, which are interconnected by Cs+, Na+ and Dy3+ ions. Solid solutions of CsNa2Y2(1−x)Dy2x (BO3)(PO4)2 (x = 0 − 0.08) are prepared and exhibit a yellow emissive luminescence by near-UV excitation due to the 4F9/2 → 6H(13/2, 15/2) transitions of Dy3+. The optimized concentration of Dy3+ is x = 0.01, and if over this critical value, the luminescent intensity will decrease due to concentration quenching. The Commission International de L’Eclairage (CIE) coordinates for CsNa2Y1.98Dy0.02(BO3)(PO4)2 are (x = 0.377, y = 0.404), corresponding to yellow color. The prepared phosphor may serve as a yellow phosphor for NUV-excited LEDs.

KNa2Lu(BO3)2: A Rare-Earth Borate Crystal Characterized by an Enhanced Birefringence and Wide Ultraviolet Transparency Range.

Borate materials are of significant interest due to their versatile structural configuration and competitive ultraviolet (UV) transparency range. In this study, we present a novel rare-earth borate crystal, KNa2Lu(BO3)2, synthesized for the first time through a facile spontaneous crystallization method. It adopts the centrosymmetric space group Pnma (no. 62) and yields a unique three-dimensional (3D) structural network formed by isolated [BO3] plane triangles and distorted [LuO7] polyhedra. This compound displays excellent thermal stability up to ∼990 °C, demonstrating a favorable congruent melting nature. Moreover, KNa2Lu(BO3)2 achieves a notably short UV absorption cutoff at approximately 204 nm, yielding a large band gap of 5.58 eV. Remarkably, it showcases an enlarged birefringence of 0.044 at 1064 nm, implying its potential as a birefringent material. Moreover, density functional theory calculations demonstrate that the optical characteristics are predominantly influenced by fundamental building blocks [BO3] triangles and distorted [LuO7] polyhedra. Our findings demonstrate the potential of KNa2Lu(BO3)2 in the development of a birefringent candidate and enrich the structural chemistry of rare-earth-based borates.

Cu3 BiS3 : Two-Dimensional Coordination Induces Out-of-Plane Phonon Scattering Enabling Ultralow Thermal Conductivity.

The discovery of compounds with low thermal conductivity and the understanding of their microscopic mechanisms are of great challenges and scientific significance. Herein, we report a unique ternary sulfide compound, Cu3 BiS3 , in which all Cu atoms are coordinated within a two-dimensional [CuS3 ] triangle plane. This local coordination leads to efficient out-of-plane phonon scattering and an ultralow thermal conductivity. Through DFT phonon spectrum calculations and analyses, we reveal that the lowest vibration frequency decreases from 2 THz for high-dimensional [CuS4 ] tetrahedral coordinated Cu atoms in CuBiS2 (CN=4, with an average Cu-S bond length of 2.328 Å) to 1.5 THz for low-dimensional [CuS3 ] triangular coordinated Cu atoms in Cu3 BiS3 (CN=3, with a shorter Cu-S bond length of 2.285 Å). This is due to the out-of-plane thermal vibration of the Cu atoms in the latter. Consequently,Cu3 BiS3 exhibits one of the lowest values of κlat (0.32 W/m K) among its peer, with a 36 % reduction compared to CuBiS2 (0.50 W/m K). This groundbreaking discovery highlights the significant role of 2D local coordination in reducing thermal conductivity through characteristic out-of-plane phonon scattering, while also contributing to a large Grüneisen parameter (2.06) in Cu3 BiS3 .

Cu3BiS3: Two‐Dimensional Coordination Induces Out‐of‐Plane Phonon Scattering Enabling Ultralow Thermal Conductivity

AbstractThe discovery of compounds with low thermal conductivity and the understanding of their microscopic mechanisms are of great challenges and scientific significance. Herein, we report a unique ternary sulfide compound, Cu3BiS3, in which all Cu atoms are coordinated within a two‐dimensional [CuS3] triangle plane. This local coordination leads to efficient out‐of‐plane phonon scattering and an ultralow thermal conductivity. Through DFT phonon spectrum calculations and analyses, we reveal that the lowest vibration frequency decreases from 2 THz for high‐dimensional [CuS4] tetrahedral coordinated Cu atoms in CuBiS2 (CN=4, with an average Cu−S bond length of 2.328 Å) to 1.5 THz for low‐dimensional [CuS3] triangular coordinated Cu atoms in Cu3BiS3 (CN=3, with a shorter Cu−S bond length of 2.285 Å). This is due to the out‐of‐plane thermal vibration of the Cu atoms in the latter. Consequently,Cu3BiS3 exhibits one of the lowest values of κlat (0.32 W/m K) among its peer, with a 36 % reduction compared to CuBiS2 (0.50 W/m K). This groundbreaking discovery highlights the significant role of 2D local coordination in reducing thermal conductivity through characteristic out‐of‐plane phonon scattering, while also contributing to a large Grüneisen parameter (2.06) in Cu3BiS3.

X-ray diffractometer, FTIR and theoretical approach of topological analysis of covellite single crystal

Covellite (CuS) is a mineral sulfide with a multitude of potential applications in various technical fields. While it possesses a basic formula, its structure is complex, featuring alternating layers of planar CuS3 triangles and CuS4 tetrahedrons interconnected by S–S bonds. To gain a deeper understanding of Covellite's structural, mechanical and electrical properties, as well as its chemical bonding, extensive research utilizing X-ray diffractometer, FTIR and first-principles calculations have been conducted on its covalent Structure (CuS). The DFT and DFT + U methods were employed, revealing their sensitivity to the correlation treatment (U value). Although a universal U value cannot be determined, this investigation identifies U = 5.5 eV as an appropriate quantity. The examination of the electronic structure uncovers a significant metallic character attributable to the p(S)-d(Cu) orbital interactions up to the Fermi level. Moreover, the estimated density of states illustrates that the atomic contribution primarily arises from the 3d1 orbitals, which ultimately induce the [2D] plane conductivity anisotropy of Covellite. Additionally, the electron density underwent a topological analysis using the Quantum ESPRESSO PW software, leading to the computation of two distinct topological charges associated with Cu. This finding substantiates the presence of an iconic model featuring mixed charges. The covalent nature of the S–S bond receives support from the DFT analysis, and it is plausible that the preferential cleavage of CuS occurs at the [2D] surface, specifically at the CuS bond. It is worth noting that the S atoms constitute the majority of the cell volume and possess a dominant influence on the crystal's compressibility.

New Functional Groups Design toward High Performance Ultraviolet Nonlinear Optical Materials.

ConspectusThe invention of the laser is a pivotal milestone in the evolution of modern science and technology. Second-order nonlinear optical (NLO) crystals, which possess the ability to convert frequencies, have found widespread applications in laser science, information transmission, industrial Internet, and other cutting-edge fields within materials and optics. As modern science and technology continue to advance at a rapid pace, existing ultraviolet (UV) and deep ultraviolet (DUV) NLO crystals struggle to meet the ever-growing demands of various applications. Consequently, the development of novel UV and DUV NLO crystals has become an urgent necessity. For a UV NLO crystal to be considered outstanding in the UV/DUV range, it must exhibit three fundamental yet crucial properties: large second-order NLO coefficients, suitable birefringence, and short UV cutoff edge corresponding to a wide band gap. However, these key factors often conflict with one another, making it challenging to achieve a harmonious balance within a single crystal. It is widely believed that these mutually constrained optical properties are codetermined by microscopic NLO-active units and macroscopic structure features. Therefore, how to design high performance UV NLO-active groups to balance these three key properties is an essential scientifically question and serious challenge. In this Account, we present three strategies for designing high-performance UV NLO-active groups: (1) The "tetrahedron partial substitution" strategy by employing various substituents to replace one or more atoms in the traditional nonpolar tetrahedral groups, might achieve the aim of increasing the polarizability anisotropy and hyperpolarizability of the newly formed polar tetrahedral functional groups, such as from SO4 to SO3NH2 or SO3CH3 groups. (2) The "structure-analogue" strategy to develop a range of organic functional groups exhibiting more strong polarizability anisotropy and hyperpolarizability by using inorganic π-conjugated groups, such as BO3 and B3O6 groups, as templates. (3) The "two in one" strategy for integrating groups featuring planar triangle configurations and tetrahedrons to create NLO-active functional groups possessing large band gaps, strong hyperpolarizability, and moderate polarizability anisotropy. These three strategies successfully guide us to design and explore various kinds of organic-inorganic composite NLO crystal materials with excellent performances, like Ba(SO3CH3)2, M(SO3NH2)2 (M = Sr, Ba), C(NH2)3SO3F, KLi(HC3N3O3)·2H2O, KLi(C3H2O4)·H2O, and so on. Finally, we briefly conclude these strategies and propose some prospects for exploring new excellent UV/DUV NLO materials with practical applications. These findings could inspire novel thoughts for researchers designing new UV/DUV NLO materials and providing abundant materials used in UV/DUV regions.

Tailored Synthesis of Two Metal Borates KSrM3B2O9 (M = Al and Ga) Exhibiting Wide Ultraviolet Transparency.

Borate materials continue to command considerable attention due to their remarkable capacity for applications in deep ultraviolet (UV) wavelengths. Herein, two new metal borates KSrM3B2O9 (M = Al and Ga) were extracted via the application of flux techniques. These two crystals adopt a centrosymmetric space group P21/c (no. 14), showcasing a layered structural configuration composed of isolated [BO3] plane triangles and [AlO4]/[GaO4] tetrahedra. Thermal analysis revealed that KSrM3B2O9 (M = Al and Ga) exhibits an incongruent nature and possesses good thermal stability up to 1083 and 983 °C, respectively. Notably, these compounds display a short UV-transmission cutoff edge, approximately around 194 and 200 nm, accompanied by band gaps of 5.47 and 4.83 eV, respectively. Furthermore, KSrM3B2O9 (M = Al and Ga) demonstrates a moderate optical birefringence of 0.026 and 0.025, respectively. Additionally, first-principles calculations were employed to shed light on the intricate interplay between the structure and properties of these compounds.

Studi Etnomatematika Pada Motif Batik Troso Jepara Dalam Bentuk Geometri Dua Dimensi

This study aims to explore the concept of a flat shape in the troso batik motif, so that this concept can be developed as a teaching material for elementary school students. Data collection techniques through observation, semi-structured interviews, and document archiving. From the results of the study it is shown that many Jepara troso batik motifs can be applied as a medium to introduce mathematical concepts, especially the concept of flat geometric shapes. The geometry concept shown is in the form of flat shapes, such as square, rectangle, triangle, parallelogram, rhombus, kite, and combined plane patterns. The geometric concept found can be used as teaching material in the form of printed, visual, or other teaching materials, adapted to the learning needs of students