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The photocatalytic efficiency of graphitic carbon nitride (g-C 3 N 4) in hydrogen production is primarily hindered by its poor absorption of visible light, rapid recombination of electron-hole pairs, and the absence of hydroxyl radical formation. Herein, a novel g-C 3 N 4 nanosheets functionalized with sulfonic acid groups were effectively produced through thermal polymerization of melamine and 2, 4-diamino-6-phenyl-1, 3, 5-triazine (DPT), followed by sulfonation treatment. The introduction of the phenyl group brings about alterations to the initial symmetrical arrangement of g-C 3 N 4 , leading to the disruption of certain hydrogen bonds. This, in turn, facilitates the movement of electrons from the n to π* orbitals, resulting in enhanced light absorption and improved efficiency in charge separation. Moreover, it induces modifications to the band structure and amplifies the production of hydroxyl radicals. Additionally, the introduction of sulfonic acid enhances the water affinity and the ability of dispersing graphitic carbon nitride in water. The optimized sulfonated benzene-substituted g-C 3 N 4 (1000-BCN-SO 3 H) with a melamine to DPT ratio of 4:1 exhibits a maximum hydrogen production rate of 6.52 mmol·h−1·g−1 under simulated sunlight irradiation with good cycling stability, which is 3.93 times higher than that of g-C 3 N 4 nanosheets. This research offers a promising opportunity for a novel approach in advancing carbon nitride materials for effective photocatalytic processes. [Display omitted] • Sulfonated benzene functionalized g-C 3 N 4 was prepared by thermal polymerization and sulfonation reactions. • Sulfonation created many voids and enhanced the hydrophilicity and water dispersion. • The increased absorption at 490 nm was due to the process of n→π* excitation. • 1000-BCN-SO 3 H nanosheets exhibit excellent photocatalytic performance and stability. • The hydrogen evolution of 1000-BCN-SO 3 H is 3.93 times that of pure g-C 3 N 4. [ABSTRACT FROM AUTHOR]

As the deployment of artificial intelligence (AI) models in real-world settings grows, their open-environment robustness becomes increasingly critical. This study aims to dissect the robustness of deep learning models, particularly comparing transformer-based models against CNN-based models. We focus on unraveling the sources of robustness from two key perspectives: structural and process robustness. Our findings suggest that transformer-based models generally outperform convolution-based models in robustness across multiple metrics. However, we contend that these metrics may not wholly represent true model robustness, such as the mean of corruption error. To better understand the underpinnings of this robustness advantage, we analyze models through the lens of Fourier transform and game interaction. From our insights, we propose a calibrated evaluation metric for robustness against real-world data, and a blur-based method to enhance robustness performance. Our approach achieves state-of-the-art results, with mCE scores of 2.1% on CIFAR-10-C, 12.4% on CIFAR-100-C, and 24.9% on TinyImageNet-C. [ABSTRACT FROM AUTHOR]

A series of Ca 5- x (PO 4) 2 SiO 4 : x Eu3+ red-emitting phosphors were synthesized through solid-state reaction, and alkali metal ions A+ (A = Li, Na and K) were co-doped in Ca 5 (PO 4) 2 SiO 4 :Eu3+ to improve its luminescence property. The impacts of synthesis temperature, luminescence center Eu3+ concentration and charge compensator A+ on the structure and luminescence property of samples were studied in detail. X-ray diffraction results indicated that prepared Ca 5 (PO 4) 2 SiO 4 :Eu3+, A+ had a standard Ca 5 (PO 4) 2 SiO 4 structure with space group P 6 3 / m. Under the excitation of 392 nm, Ca 5 (PO 4) 2 SiO 4 :Eu3+ phosphors showed a red emission consisting of several emission peaks at 593 nm, 616 nm and 656 nm, relevant to 5D 0 →7F 1 , 5D 0 →7F 2 and 5D 0 →7F 4 electron transitions of Eu3+ ions, respectively. Luminescence intensity and lifetime of Ca 5 (PO 4) 2 SiO 4 :Eu3+ can be significantly enhanced through co-doping alkali metal ion A+, which play an important role as charge compensator. The results suggest that Ca 5 (PO 4) 2 SiO 4 :Eu3+, A+ red phosphors with excellent luminescence property are expectantly served as red component for white light-emitting diodes excited by near-ultraviolet. [ABSTRACT FROM AUTHOR]

• A bicriteria approximation algorithm for Max k -Uncut with ratio at least 1/2. • A bicriteria approximation algorithm for Densest k -Subgraph with ratio at least 1/4. • A new perspective to the Densest k -Subgraph problem. The Max k -Uncut problem arose from the study of homophily of large-scale networks. Given an n -vertex undirected graph G = (V , E) with nonnegative weights defined on edges and a positive integer k , the Max k -Uncut problem asks to find a partition { V 1 , V 2 , ⋯ , V k } of V such that the total weight of edges that are not cut is maximized. This problem is the complement of the classic Min k -Cut problem, and was proved to have surprisingly rich connection to the Densest k -Subgraph problem. In this paper, we give an approximation algorithm for Max k -Uncut using a non-uniform approach combining LP-rounding and the greedy strategy. The algorithm partitions the vertices of G into at least (1 − 1 e) k parts in expectation, and achieves a good expected approximation ratio 1 2 (1 + (n − k n) 2). [ABSTRACT FROM AUTHOR]

Y 2- x (MoO 4) 3- y (BO 3) y : x Sm3+ and Y 2- x (MoO 4) 3- y (PO 4) y : x Sm3+ orange-red phosphors were synthesized using a conventional solid-state reaction. The effects of Sm3+ doping concentration and substitution by anion groups BO 3 3− and PO 4 3− on the crystal structure and luminescent performance were studied in detail. XRD results indicated that all samples had a standard Y 2 (MoO 4) 3 structure with space group Pbcn, and BO 3 3− and PO 4 3− entered the lattice without initiating an impurity phase. At an excitation of 404 nm, the Y 2- x (MoO 4) 3 : x Sm3+ orange-red phosphors exhibited three narrow-band emissions at 567 nm, 605 nm, and 652 nm, due to transitions of 4G 5/2 → 6H 5/2 , 4G 5/2 → 6H 7/2 and 4G 5/2 → 6H 9/2 of Sm3+, respectively. In addition, substitution of MoO 4 2− by BO 3 3− and PO 4 3− resulted in significant improvement of the luminescence of the Y 2 (MoO 4) 3- y (BO 3) y :Sm3+ and Y 2 (MoO 4) 3- y (PO 4) y :Sm3+ phosphors compared to Y 2 (MoO 4) 3 :Sm3+ phosphors, especially in terms of luminescent intensity. The results indicated that Y 1.9 (MoO 4) 2.97 (BO 3) 0.03 :0.1Sm3+ and Y 1.9 (MoO 4) 2.94 (PO 4) 0.06 :0.1Sm3+ orange-red phosphors, having excellent luminescence, are promising orange-red components for warm white light-emitting diodes. [ABSTRACT FROM AUTHOR]

Abstract Post-synthesis treatment is an effective way to modify zeolites to acquire desirable properties. Here, we present an ultrafast post-synthesis treatment to prepare core-shell structured zeolite, which is composed of a ZSM-5 core and a silicalite-1 shell. The pure silica shell, which is aimed to remove the Brønsted acid sites associated with the framework Al on the external surface of aluminosilicate core, was formed unprecedentedly within several minutes by our method. Complementary techniques, such as XRD, TG/DTA, SEM, TEM, ICP, and XPS, were employed to verify the successful coverage of the silicalite-1 shell onto the ZSM-5 core. By adjusting the treating period, temperature, and reactant compositions, the thickness of the shell can be easily tuned. Further, this ultrafast process enabled the establishment of a continuous flow reaction system, which could allow the mass production of core-shell structured zeolite catalysts. Graphical abstract Description: An established ultrafast post-synthesis treatment resulted in the formation of coreshell structured ZSM-5@Silicalite within only several minutes. Thickness of the shell formed can be facilely controlled by this treatment. Image 1 Highlights • Core-shell structured ZSM-5@Silicalite-1 catalyst was prepared within only several minutes. • The silcalite-1 shell thickness can be facilely controlled. • The ultrafast preparation enabled the establishment of a continuous flow reaction system. [ABSTRACT FROM AUTHOR]

The present study focuses on the ultrafast synthesis of *BEA zeolite, which constitutes one of the most industrially important zeolites. A pure *BEA phase was successfully synthesized within 10 min at 210 °C by carefully tuning the composition of the initial reactant mixture. To date, the ultrafast synthesis of several industrially important zeolites is achieved with the aid of aging pretreatment, followed by high temperature hydrothermal treatment. In this study, we first demonstrated the 10-min synthesis of *BEA zeolite employing organic structure-directing agents (OSDAs), without any aging process. The employment of sealed pipe reactor in conjunction with the optimization of chemical composition of starting materials are critical in obtaining pure *BEA phase in a short time. The fast-synthesized *BEA zeolite possesses properties that are similar to those synthesized by conventional hydrothermal synthesis methods in terms of crystallinity and micropore volume. A comprehensive investigation on the effects of various parameters on the seed-assisted crystallization of *BEA zeolite was also studied. [ABSTRACT FROM AUTHOR]

• Aluminum phosphate protection material had high compatibility with limestone. • The mechanical strength of limestone weathering layer was improved by aluminum phosphate. • The wettability of the weathering layer was reduced and the durability was improved. • Aluminum phosphate was nucleated and stacked in situ with the aid of limestone matrix. The surface weathering of open-air limestone caused by long-term acid-rain erosion and thermal stress is an urgent issue to solve. In this study, seven concentrations of diammonium phosphate and aluminum chloride hexahydrate (fixed molar ratio of 1000:1) were used to generate aluminum phosphate protective materials in situ with high lattice matching with calcite for surface consolidation. The compatibility test, mechanical property evaluation, and protective mechanism of the material were elucidated by color change, porosity, permeability, surface hardness, infinite compressive strength, Fourier-transform infrared spectroscopy, and scanning electron microscopy–energy-dispersive X-ray spectroscopy. It was found that aluminum phosphate had good aesthetic compatibility and water–vapor exchange balance with the matrix and surrounding environment. Meanwhile, the surface coating grown by crystal accumulation could play a role in filling pores and agglomerated particles, thereby improving the hardness (83.5 HD), infinite compressive strength (4.05 MPa), and acid-rain erosion resistance of the limestone weathering layer. Aluminum phosphate can play a vital role in the treatment and prevention of limestone surface-weathering diseases and has high research value and broad application prospects. [ABSTRACT FROM AUTHOR]