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Methane gas leakage can lead to pollution problems, such as rising ambient temperature. In this paper, the Vernier effect of a double D-shaped photonic crystal fiber (PCF) in a Sagnac interferometer (SI) is proposed for the accurate detection of mixed methane gas content in the gas. The optical fiber structure of the effective sensing in the sensing SI loop and the effective sensing in the reference SI loop are the same. Both of them adopt the polarization-maintaining photonic crystal fiber (PM-PCF) designed in this paper. The optical fiber structure of the effective sensing in the sensing SI loop deposited with the methane gas-sensitive film is polished to obtain a double-D structure. This operation makes it easier for methane gas to contact the sensitive film and realize the sensor's repeated use. The sensing capability of the methane gas sensor was evaluated utilizing the finite element method (FEM). The numerical simulation results show that when the concentration of methane gas in the environment is 0~3.5%, the average sensitivity of two parallel Sagnac loops is 409.43 nm/%. Using Vernier effect cascade SI loops, the sensitivity of the sensor for detecting methane gas increased by four times. Without considering air and humidity, we provide a practical scheme for the development and design of high-sensitivity methane gas sensors. [ABSTRACT FROM AUTHOR]

Titanium alanate Ti(AlH4)4 is a candidate material for high‐density hydrogen storage that thus far has been scarcely investigated. This study determines the low energy structures of Ti(AlH4)4 by adopting a global optimization algorithm combined with density functional theories, and systematically compares their stabilities, electronic structures, and bonding properties with Mg(AlH4)2 and Ca(AlH4)2. Compared to other compounds, Ti(AlH4)4 is less stable and the Ti−H bond is of covalent nature with strong polarities. The covalent Ti−H interaction can weaken the Al−H bonds. Because both the ionic and covalent interactions of the Al−H bonds are the weakest in Ti(AlH4)4, it is favorable for the desorption of hydrogen. [ABSTRACT FROM AUTHOR]

Despite significant advancements in leveraging artificial intelligence (AI) for drug design, materials science, and other fields, the question of how each dataset feature influences a target metric—essential for constructing better predictive models and targeted materials design—remains largely unaddressed. In this study, we explored the application of interpretable machine learning (ML) techniques to the inverse design of two-dimensional (2D) semiconductor materials, a critical yet underexplored area within the AI4Science domain. Our approach utilized a dataset from the C2DB database, incorporating advanced feature engineering and data imputation strategies to predict material stability, a key determinant of a materials industrial and academic value. Through the calculation of Shapley additive explanation scores and counterfactual analysis, we provided a nuanced understanding of feature contributions toward material stability, enabling the targeted design of 2D semiconductors with optimized properties. This work not only fills the gap in the current literature by emphasizing the role of interpretability in materials design but also demonstrates the potential of interpretable ML in guiding the development of novel materials with enhanced performance characteristics. [ABSTRACT FROM AUTHOR]

A novel highly sensitive D-shaped photonic crystal fiber-based surface plasmon resonance (PCF-SPR) sensor for dual parameters of refractive index and temperature detecting is proposed. A PCF cladding polishing provides a D-shape design with a gold (Au) film coating for refractive index (RI) sensing (Core 1) and a composite film of silver (Ag) and polydimethylsiloxane (PDMS) for temperature sensing (Core 2). Comsol Multiphysics 5.5 is used to design and simulate the proposed sensor by the finite element method (FEM). The proposed sensor numerically provides results with maximum wavelength sensitivities (WSs) of 51,200 and 56,700 nm/RIU for Core 1 and 2 as RI sensing while amplitude sensitivities are −98.9 and −147.6 RIU−1 with spectral resolution of 1.95 × 10−6 and 1.76 × 10−6 RIU, respectively. Notably, wavelength sensitivity of 17.4 nm/°C is obtained between −20 and −10 °C with resolution of 5.74 × 10−3 °C for Core 2 as temperature sensing. This sensor can efficiently work in the analyte and temperature ranges of 1.33–1.43 RI and −20–100 °C. Due to its high sensitivity and wide detection ranges, both in T and RI sensing, it is a promising candidate for a variety of applications, including chemical, medical, and environmental detection. [ABSTRACT FROM AUTHOR]

Over the past century, ferroelectricity has offered exciting opportunities for fundamental research and device applications. However, most of the discovered excellent ferroelectrics are oxide materials with large band gaps, limiting their potential for optoelectronics applications. Here using first-principles calculations we identify a new narrow-gap ferroelectric beyond oxides, i.e., ferroelectric perovskite sulphide BaZrS3. Under large compressive strains, BaZrS3 can be stabilized into a unique super-tetragonal phase with an extraordinary polarization of 67.16 µC/cm2, which is even stronger than that of conventional oxide ferroelectrics. Excitingly, the supertetragonal BaZrS3 exhibits a direct narrow band gap of 1.2 eV and excellent electronic properties. Based on the chemical bonding analysis, we attribute the formation of supertetragonal phase to charge re-ordering in which the π bond overlap along the long 〈Zr-S〉 bond completely vanishes and the antibonding states of the σ bond appear below the Fermi level. Our work provides a conceptual strategy for designing new ferroelectrics for electronic and photovoltaic applications. [ABSTRACT FROM AUTHOR]

Carbon nanofibers with various contents of Co nanoparticle were synthesized by a two step process of electrospinning and subsequent heat treatment. The thermal stability,phase composition,microstructure and electromagnetic characteristics of the carbon nanofibers were characterized by differential scanning calorimetry-thermogravimmetric analysis (DSC-TGA),X-ray diffraction(XRD),scanning electron microscope(SEM) and vector network analyzer(VNA),and the microwave absorption performance was studied.The results indicate that the crystallinity of composite nanofibers is moderate when the carbonization temperature is 800℃.The amorphous carbon is partially converted into graphite and CoAc2 completely reduces to face-centered cubic structured Co nanoparticle. The fiber is intact and beads-on-string structure exists in the fiber networks. The electromagnetic characteristics of the carbon nanofibers significantly improve by the doping of Co. The Carbon nanofibers containing 7%(mass fraction) as fillers with thickness of 1.5mm exhibit maximum effective absorption bandwidth of 4.5GHz, and it is obviously improved compared to pure carbon nanofibers.

In this study, a three-rib intersecting composite diamond honeycomb structure is fabricated by interlocking technology. The mechanical properties of the composite interlocked diamond honeycomb (CIDH) and corresponding sandwich structure (CIDHSS) are experimentally tested. The stiffness, strength, and failure characteristics of CIDH and CIDHSS are analyzed. The results show that CIDH has better mechanical properties than the interlocked Kagome and square honeycombs. The edge effect limits the edge compressive strength and stiffness of CIDH. Debonding is the main failure mode that limits both bending and compressive strength of CIDHSS. The reinforced plate added to the edge effectively improves the anti-debonding ability. [ABSTRACT FROM AUTHOR]