Dynamic Spatial-Selective Metasurface with Multiple-Beam Interference.

The emergence of the metasurface has provided a versatile platform for the manipulation of light at the nanoscale. Recent research in metasurfaces has explored a plethora of dynamic control and switching of multifunctionalities, paving the way for innovative applications in fields such as imaging, sensing, and communication. However, current dynamic multifunctional metasurfaces face challenges in terms of functional scalability and selective activation. In this work, we introduce and experimentally demonstrate a strategy that utilizes multiple plane waves to create arbitrary periodic patterns on the metasurface, thus enabling the dynamic and arbitrary spatial-selective activation of its embedded multiplexed functionalities. Furthermore, our strategy facilitates dynamic light control through mechanical translation, as demonstrated by a high-speed, dynamically switchable beam deflection scenario. Our method effectively overcomes the limitations associated with traditional spatially multiplexing techniques, offering greater flexibility and selectivity for dynamic control in multifunctional metasurfaces.

Quantifying the Growth Kinetics of Lithium Metal Reduced from Solid Ionic Conductors.

Investigating the growth kinetics of Li metal in solid-state batteries is crucial to both a fundamental understanding and practical application. Here, by directly observing the formation of Li metal from Ta-doped Li6.4La3Zr1.4Ta0.6O12 (LLZTO) in a transmission electron microscope, the growth kinetics is analyzed quantitatively. The growth kinetics of Li deposits shows a cubic-curve characteristic for LLZTO with Li-source-free. Instead, a linear growth process is observed with Li-source supplied. The impact of the illuminating electron dose rate on the growth kinetics is clarified, indicating that even low dose rates (1-3 e-/Å2/s) could affect Li growth, highlighting the significance of controlling dose rates. Furthermore, a new pathway for the formation of Li metal from Li-containing materials utilizing the field-emission effect is reported. This work has implications on the failure mechanism in solid batteries by using limited Li anodes and opens pathways for regulating Li growth in LLZTO at various scenarios, which can also extend to other ionic conductors.

Design of Deep-Ultraviolet Zero-Order Waveplate Materials by Rational Assembly of [AlO2F4] and [SO4] Groups.

Zero-order waveplates are widely used in the manufacture of laser polarizer waves, which are important in polarimetry and the laser industry. However, there are still challenges in designing deep-ultraviolet (DUV) waveplate materials that satisfy large band gaps and small optical anisotropy simultaneously. Herein, three cases of aluminum sulfate fluorides: Na2AlSO4F3, Li4NH4Al(SO4)2F4, and Li6K3Al(SO4)4F4, with novel [AlSO4F3] layers or isolated [AlS2O8F4] trimers were designed and synthesized by the rational assembly of [AlO2F4] and [SO4] groups through a hydrothermal method. Experiments and theoretical calculations imply that these three possess short cutoff edges (λ < 200 nm) and small birefringence (0.0014-0.0076 @ 1064 nm), which fulfils the prerequisite for potential DUV zero-order waveplate materials. This work extends the exploration of DUV zero-order waveplate materials to the aluminum sulfate fluoride systems.

AYSO4F2 (A = K, Rb): [YO4F4] Polyhedra Enhancement of Birefringence in Non-π-Conjugated Sulfate Systems.

A mild hydrothermal method was employed to successfully synthesize two new sulfate fluorides, namely, AYSO4F2 (A = K, Rb). They are isomorphic, and both contain [YO4F4] polyhedra and [SO4] tetrahedra in the structure. Theoretical calculations and experimental tests show that AYSO4F2 (A = K, Rb) have large band gaps (7.79 and 7.82 eV) and moderate birefringence (0.015 and 0.02 @ 546.1 nm), with significantly enhanced birefringence and band gaps as compared to that of the single alkali metal sulfates A2SO4 (A = K, Rb). Furthermore, theoretical calculations show that [YO4F4] polyhedra are the main reason for the band gap and birefringence enhancement. This work contributes to the advancement of structural chemistry in the field of rare-earth sulfates, offering a novel approach for the design of sulfates characterized by large birefringence.

High-performance Complementary Electrochromic Batteries using Nb18W16O93 by the Synergistic Effects of Aqueous Al3+/K+ Dual-ion.

Multivalent ions, especially Al3+ in aqueous electrolyte contributes to higher capacity and color contrast for more sustainable post-lithium electrochromism and energy storages. However, the lack of suitable cathodic and anodic electrochromic materials is a major challenge for Al-ion electrochromic batteries, which limits their optical contrast and lifespan. Herein, we report that Wadsley-Roth phase Nb18W16O93 with open structure achieves Al3+ intercalation/extraction reversibly. The complementary electrochromic energy storage devices based on Nb18W16O93 coupled with Prussian blue using hybrid Al3+/K+ aqueous electrolytes show a fast response, a high capacity and a large coloring efficiency. The superior performances are due to the cations of Al3+ and K+ selectively insert/extract in the electrode of Nb18W16O93 and Prussian blue, respectively. This work provides an effective strategy for high-performance and low-cost electrochromic batteries with higher sustainability.

Linear π-conjugated units of the D∞h point group as superior ultraviolet birefringent units.

At present, birefringent materials face a limited selection of large structural anisotropic functional modules (FMs). In this paper, we present a series of linear units which belong to the D∞h point group represented by (BO2)- proposed as novel birefringent active FMs. By analyzing the molecular orbital of the (BO2)- unit, it is found that there are relatively fewer non-bonding orbitals in (BO2)- than in (BO3)3- and the delocalized π bonds in (BO2)- appear in shallow energy levels, which are easily excited. Through first-principles modeling and simulation, it is found that the delocalized π bonds in (BO2)- can still show obvious transition processes, which produce a significant gain to the birefringence. Besides, a series of compounds containing linear anionic frameworks which also belong to the D∞h point group show excellent optical anisotropy in the same way. Therefore, the linear anionic basic units which belong to the D∞h point group have the great potential to become new birefringent FMs.

NaB3O4F(OH): A Hydroxyfluorooxoborate with One-Dimensional Chain Featuring Large Birefringence and Short Ultraviolet Cutoff Edge.

A new sodium hydroxyfluorooxoborate, NaB3O4F(OH) (NBOFH), was discovered and synthesized. NBOFH features the unprecedented [B3O4F(OH)] infinite chain constructed by the novel fundamental building block (FBB) of [B3O5F(OH)]. NBOFH has a large birefringence of 0.097 at 1064 nm and short ultraviolet (UV) cutoff edge below 200 nm. First-principles calculations and response electron distribution anisotropy (REDA) were performed to explain the structure-property relationships. This work provides a novel strategy for the synthesis of deep-ultraviolet birefringent crystals and enriches the structural diversity of the emerging hydroxyfluorooxoborates.

Three reversible polymorphic copper(I) complexes triggered by ligand conformation: insights into polymorphic crystal habit and luminescent properties.

Three luminescent polymorphs based on a new copper(I) complex Cu(2-QBO)(PPh3)PF6 (1, PPh3 = triphenylphosphine, 2-QBO = 2-(2'-quinolyl)benzoxazole) have been synthesized and characterized by FT-IR, UV-vis, elemental analyses, and single-crystal X-ray diffraction analyses. Each polymorph can reversibly convert from one to another through appropriate procedures. Interestingly, such interconversion can be distinguished by their intrinsic crystal morphologies and colors (namely α, dark yellow plate, ß, orange block, γ, light yellow needle) as well as photoluminescent (PL) properties. X-ray crystal structure analyses of these three polymorphs show three different supramolecular structures from 1D to 3D, which are expected to be responsible for the formation of three different crystal morphologies such as needle, plate, and block. Combination of the experimental data with DFT calculations on these three polymorphs reveals that the polymorphic interconversion is triggered by the conformation isomerization of the 2-QBO ligand and can be successfully controlled by the polarity of the process solvents (affecting the molecular dipole moment) and thermodynamics (affecting the molecular total energy). It is also found that the different crystal colors of polymorphs and their PL properties are derived from different θ values (dihedral angle between benzoxazolyl and quinolyl group of the 2-QBO ligand) and P-Cu-P angles based on TD-DFT calculations. Moreover, an interesting phase interconversion between γ and ß has also been found under different temperature, and this result is consistent with the DFT calculations in which the total energy of ß is larger than that of γ. This polymorphism provides a good model to study the relationship between the structure and the physical properties in luminescent copper(I) complexes as well as some profound insights into their PL properties.

Three Polyborates with High-Symmetry [B12O24] Units Featuring Different Dimensions of Anion Groups.

Three polyborates, namely, LiNa11B28O48, Li1.45Na7.55B21O36, and Li2Na4Ca7Sr2B13O27F9, were synthesized via the high-temperature solution method. All of them feature high-symmetry [B12O24] units, yet their anion groups exhibit distinct dimensions. LiNa11B28O48 features a three-dimensional anionic structure of 3[B28O48]∞ framework, which is composed of three units: [B12O24], [B15O30], and [BO3]. Li1.45Na7.55B21O36 possesses a one-dimensional anionic structure of 1[B21O36]∞ chain consisting of [B12O24] and [B9O18] units. The anionic structure of Li2Na4Ca7Sr2B13O27F9 is composed of two zero-dimensional isolated units, namely, [B12O24] and [BO3]. The novel FBBs [B15O30] and [B21O39] are present in LiNa11B28O48 and Li1.45Na7.55B21O36, respectively. The anionic groups in these compounds exhibit a high degree of polymerization, thereby augmenting the structural diversity of borates. And the crystal structure, synthesis, thermal stability, and optical properties were meticulously discussed to guide the synthesis and characterization of novel polyborates.

Preparation and Thermal Conductivity Enhancement of Boron Nitride Nano-Material PiG Composite.

With the improvement of the conversion efficiency of LED chip and fluorescent material and the increasing demand for high-brightness light sources, LED technology has begun to move toward the direction of high-power. However, there is a huge problem that high-power LED must face with a large amount of heat generated by high power causing a high temperature thermal decay or even thermal quenching of the fluorescent material in the device, resulting in a reduction of the luminous efficiency, color coordinates, color rendering index, light uniformity, and service life of LED. In order to solve this problem, fluorescent materials with high thermal stability and better heat dissipation were prepared to enhance their performance in high-power LED environments. A variety of boron nitride nanomaterials were prepared by the solid phase-gas phase method. By adjusting the ratio of boric acid to urea in the raw material, different BN nanoparticles and nanosheets were obtained. Moreover, the control of catalyst amount and synthesis temperature can be used to synthesize boron nitride nanotubes with various morphologies. By adding different morphologies and quantities of BN material in PiG (phosphor in glass), the mechanical strength, heat dissipation, and luminescent properties of the sheet can be effectively controlled. PiG prepared by adding the right number of nanotubes and nanosheets has higher quantum efficiency and better heat dissipation after being excited by high power LED.

Sr3B14O24: a new borate with a [B14O30] fundamental building block and an unwonted 2D double layer.

A new alkaline-earth metal borate, Sr3B14O24, was successfully synthesized by a high-temperature solution method. It crystallizes in the monoclinic space group P21/c (no. 14) and features a fundamental building block (FBB) [B14O30] which is composed of eight [BO3] and six [BO4] units. The FBBs further condense to form an unwonted infinite 2D double layer extended in the bc plane. The UV-Vis-NIR diffuse reflectance spectrum shows that the cutoff edge of Sr3B14O24 is less than 200 nm, which indicates its potential use in the deep UV region. In addition, the first principles theoretical study was carried out to better understand the relationship between the structure and performance.

RbPb8O4Cl9: the first alkali metal lead oxyhalide with distorted [PbO3Cl3] and [PbOCl5] mixed-anion groups.

A new heavy metal oxychloride, RbPb8O4Cl9, has been synthesized by a high-temperature solution method. The compound crystallizes in the centrosymmetric space group P4/n (no. 85) and exhibits a three-dimensional (3D) framework constructed from [PbO3Cl3], [PbOCl5] and [RbCl8] polyhedra. RbPb8O4Cl9 is an indirect band gap compound with an experimental band gap of 3.66 eV. The first-principles calculations indicate that the band gap mainly originated from the interaction of Pb 6p, O 2p and Cl 2p states. Meanwhile, the calculated birefringence of RbPb8O4Cl9 is about 0.012 at 1064 nm. The compound is the first alkali metal lead oxyhalide, which enriches the structural diversity of oxyhalides and provides an insight for the exploration of new functional materials.

Effects of and prognostic factors affecting endovascular mechanical thrombectomy of acute vertebrobasilar artery occlusion.

PURPOSE: To investigate the clinical outcome and factors affecting the prognosis of endovascular mechanical thrombectomy of acute vertebrobasilar artery occlusion. MATERIALS AND METHODS: Eighty-three patients with acute vertebrobasilar artery occlusion were treated with endovascular mechanical thrombectomy, and the recanalization rate, clinical outcomes at three months, modified DWI-PC-ASPECTS, and MRA-BATMAN scores were analyzed. RESULTS: Following acute mechanical thrombectomy, the TICI 2B-3 score was achieved in all patients (100%). At three-month evaluation, 56 (67.5%) patients had good prognosis with the mRS score of 0-2, including 13 (23.2%) patients who had arterial occlusion caused by emboli and 43 (76.8%) who had atherosclerotic stenosis. In analyzing factors affecting the prognosis, a significant difference (P < 0.05) existed between patients with good (mRS 0-2) and poor (mRS 3-6) prognosis in the NIHSS (17.3 vs. 31.2, P = 0.000001), modified DWI-PC-ASPECTS (10.4 vs. 7.8, P = 0.021), and MRA-BATMAN (6.3 vs. 4.6, P = 0.003) scores. Univariate Logistic regression analysis demonstrated NIHS score ≥ 21, modified DWI-PC-ASPECTS score ≤ 8.5, and MRA-BATMAN score ≤ 6.5 to be the risk factors for poor prognosis. Multivariate Logistic regression analysis revealed NIHSS score ≥ 21 as an independent risk factor for poor prognosis. CONCLUSION: Endovascular mechanical thrombectomy is safe and effective in recanalizing occluded vertebrobasilar artery occlusion, and NIHS score ≥ 21, modified DWI-PC-ASPECTS score ≤ 8.5, and MRA-BATMAN score ≤ 6.5 are the risk factors for poor prognosis.

Two-dimensional dysprosium(III) triiodate(V) dihydrate, Dy(IO(3))(3)(H(2)O)·H(2)O.

During our research into novel nonlinear optical materials using 1,10-phenanthroline as an appending ligand on lanthanide iodates, crystals of an infinite layered Dy(III) iodate compound, Dy(IO(3))(3)(H(2)O)·H(2)O, were obtained under hydro-thermal conditions. The Dy(III) cation has a dicapped trigonal prismatic coordination environment consisting of one water O atom and seven other O atoms from seven iodate anions. These iodate anions bridge the Dy(III) cations into a two-dimensional structure. Through O-H⋯O hydrogen bonds, all of these layers stack along [111], giving a supra-molecular channel, with the solvent water mol-ecules filling the voids.

Poly[(µ(5)-5-carboxylatotetrahydrofuran-2,3,4-tricarboxylic acid)sodium].

The search for the novel metal-organic frameworks (MOFs) materials using tetra-hydro-furan-2,3,4,5-tetra-carboxylic acid (THFTCA) as a versatile multi-carboxyl ligand, lead to the synthesis and the structure determination of the title compound, [Na(H(3)THFTCA)] or [Na(C(8)H(7)O(9))](n), which was obtained by a solution reaction at room temperature. The ligand is mono-deprotonated, coordinating five sodium ions through one furan oxygen atom and six carboxyl oxygen atoms. The sodium ion exhibits a distorted penta-gonal-bipyramidal NaO(7) geometry consisting of seven O atoms derived from five surrounding ligands. Two adjacent pentagonal bipyramids share an O-O edge, forming a dinuclear sodium cluster. Finally, these clusters are effectively linked by the carboxyl groups of THFTCA ligands, forming a firm metal organic framework and O-H⋯O hydrogen bonds contribute to the crystal packing.

Bipolar high-repetition-rate high-voltage nanosecond pulser.

The pulser designed is mainly used for producing corona plasma in waste water treatment system. Also its application in study of dielectric electrical properties will be discussed. The pulser consists of a variable dc power source for high-voltage supply, two graded capacitors for energy storage, and the rotating spark gap switch. The key part is the multielectrode rotating spark gap switch (MER-SGS), which can ensure wider range modulation of pulse repetition rate, longer pulse width, shorter pulse rise time, remarkable electrical field distortion, and greatly favors recovery of the gap insulation strength, insulation design, the life of the switch, etc. The voltage of the output pulses switched by the MER-SGS is in the order of 3-50 kV with pulse rise time of less than 10 ns and pulse repetition rate of 1-3 kHz. An energy of 1.25-125 J per pulse and an average power of up to 10-50 kW are attainable. The highest pulse repetition rate is determined by the driver motor revolution and the electrode number of MER-SGS. Even higher voltage and energy can be switched by adjusting the gas pressure or employing N(2) as the insulation gas or enlarging the size of MER-SGS to guarantee enough insulation level.

Enhanced Transparency of Rough Surface Sapphire by Surface Vitrifaction Process.

A novel, simple, and low-cost in situ surface vitrification method has been effectively developed to enhance the optical transparency of rough surface sapphire at UV-visible-IR regions. This method is to obtain a glass layer on the sapphire surface through vitrifaction process. The thickness, refractive index, components and transition temperature of the glass layer have been investigated and discussed respectively by XRD, DSC, SEM and EDS elemental analysis. The experimental results show that the vitrified sapphire has high transparency even after 1000 °C annealing at UV-visible-IR regions.

Chronic recurrent autoimmune uveitis with progressive photoreceptor damage induced in rats by transfer of IRBP-specific T cells.

Recurrent uveitis is a common cause of vision blindness. Using a rat model of chronic recurrent uveitis, we examined the relationship between clinical expression, pathological changes, and the heterogeneity of the disease. Chronic recurrent uveitis was induced by adoptive transfer of interphotoreceptor retinoid-binding protein (IRBP)-specific T cells in a total of more than 60 Lewis rats. In about 75% of cases recurrent uveitis was pathologically a chronic and progressive disease. The major pathological changes included the gradual loss of photoreceptor cells. However, disease progression did not always parallel the severity of ocular inflammation and clinical recurrent disease, with about a quarter showing no pathological damage in the eye.