A fault diagnosis method for wireless sensor network nodes based on a belief rule base with adaptive attribute weights.

Due to the harsh operating environment and ultralong operating hours of wireless sensor networks (WSNs), node failures are inevitable. Ensuring the reliability of the data collected by the WSN necessitates the utmost importance of diagnosing faults in nodes within the WSN. Typically, the initial step in the fault diagnosis of WSN nodes involves extracting numerical features from neighboring nodes. A solitary data feature is often assigned a high weight, resulting in the failure to effectively distinguish between all types of faults. Therefore, this study introduces an enhanced variant of the traditional belief rule base (BRB), called the belief rule base with adaptive attribute weights (BRB-AAW). First, the data features are extracted as input attributes for the model. Second, a fault diagnosis model for WSN nodes, incorporating BRB-AAW, is established by integrating parameters initialized by expert knowledge with the extracted data features. Third, to optimize the model's initial parameters, the projection covariance matrix adaptive evolution strategy (P-CMA-ES) algorithm is employed. Finally, a comprehensive case study is designed to verify the accuracy and effectiveness of the proposed method. The results of the case study indicate that compared with the traditional BRB method, the accuracy of the proposed model in WSN node fault diagnosis is significantly improved.

Discovery of NLO Semiorganic (C5H6ON)+(H2PO4)-: Dipole Moment Modulation and Superior Synergy in Solar-Blind UV Region.

We herein report a novel semiorganic NLO material, (C5H6ON)+(H2PO4)-, 4HPP, showing promising excellent properties in the important solar-blind UV region where LAP and its deuterated form DLAP are the only commercialized semiorganic materials. For the first time, the 4-hydroxypyridine (4HP+, (C5H6ON)+) cation is identified as NLO active and how to eliminate the dipole-dipole interaction to avoid the unwanted center-symmetry-trap caused by the polar-induced susceptibility is well demonstrated. Remarkably, 4HPP exhibits competitive and even better properties compared with LAP that include better thermal stability (decomposition at 166 vs 112 °C of LAP); wider transparency range (0.26-1.50 µm); very strong SHG response (3 × KDP); a suitable large birefringence (Δncal = 0.25 vs 0.075 of LAP); and a high laser-induced damage threshold (2.2 × KDP). First-principles calculations show that the π-conjugated organic (4HP)+ cation governs the optical anisotropy, whereas the synergy of the organic and inorganic moieties dominates the SHG process. Our discovery points out a new path for the rational design of high performance semiorganic materials that require an acentric structure.

A Ratiometric and Colorimetric Hemicyanine Fluorescent Probe for Detection of SO2 Derivatives and Its Applications in Bioimaging.

Based upon the intramolecular charge transfer (ICT) mechanism, a novel ratiometric fluorescent probe EB was developed to detect SO32-/HSO3-. The probe displayed both colorimetric and ratiometric responses toward SO32-/HSO3-. It displayed a quick response (within 60 s), good selectivity and high sensitivity (a detection limit of 28 nM) towards SO32-/HSO3-. The SO32-/HSO3- sensing mechanism was confirmed as the Michael addition reaction by ESI-MS. Moreover, the probe could be applied to measure the level of sulfite in real samples, like sugar and chrysanthemum, and it could also be used to detect SO32-/HSO3- in HepG2 cells through confocal fluorescence microscopy, which proved its practical application in clinical diagnosis.

How To Maximize Birefringence and Nonlinearity of π-Conjugated Cyanurates.

Materials with large birefringence (Δn) are highly needed by fiber-optic isolators, whereas crystals showing strong second-order harmonic generation (SHG) are the key component for all-solid-state laser devices. Cyanurate constructed by the planar π-conjugated ring (C3N3O3, CY) is a class of fascinating materials exhibiting not only very large Δn (larger than that of calcite) but also strong SHG (2 times that of ß-BaB2O4, BBO). Here, we report five new cyanurates (I-V) and their single-crystal structures; among them, II realizes a Δn = 0.4, the maximum in the cyanurate family, and IV realizes a d33 = 6.69 pm/V, one of the highest values in the cyanurate family. We discover a dependence between Δn and the coplanarity of the CY rings that is explicitly described by a Boltzmann function, in which the coplanarity is defined by the dihedral angle (γ) between the CY plane and the principal optical axes XY plane. II realizes the maximum Δn due to its zero γ that indicates perfect coplanarity. Such a Δn-γ dependence also allows the Δn prediction of cyanurates. Furthermore, we uncover that the SHG intensity of cyanurates increases monotonically as the angle (θ) between the maximum hyperpolarizability (ßmax) vector and the crystal 21 polar axis decreases. We predict the dij to extend well beyond such a value and to maximize at θ = 0°. Our results have significant implications for the future rational design and discovery of high-performance materials of π-conjugated and other related systems.