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Polylactic acid (PLA) is regarded as the most representative biomedical polymer materials. However, some problems, that is, its big brittleness, high hydrophobicity, and poor bioactivity, limit its application. Here, using poly(butylene adipate‐co‐terephthalate) (PBAT) as toughening agent, and incorporating ethylene diamine tetra(methylene phosphonic acid) (EDTMPA) for the first time with nano‐hydroxyapatite (nHA) as reinforcement filler, series of PLA/PBAT/nHA/EDTMPA as novel bone scaffold composites are successfully prepared via simple one‐step melt extrusion. The chemical composition, microstructures, thermodynamic properties, mechanical properties, hydrophilicity, and bioactivities of PLA/PBAT/nHA/EDTMPA were characterized. The test results show that these developed PLA‐based composites from safe biosources are greatly potential raw materials for bone scaffold because the existence of EDTMPA can chelate with calcium ions to promote calcium phosphate (CaP) deposition on the surface of bone scaffold composites. Especially, when the content of EDTMPA is 6 wt%, the comprehensive performance of the bone scaffold composite is the best. The research results indicate that these developed PLA‐based materials are greatly potential raw materials for bone scaffold composites. [ABSTRACT FROM AUTHOR]

In order to investigate the analysis and processing methods for nonstationary signals generated in bridge health monitoring systems, this study combines the advantages of complete ensemble empirical mode decomposition (CEEMD) and wavelet threshold denoising algorithms to construct the CEEMD–wavelet threshold denoising algorithm. The algorithm follows the following steps: first, add noise to the monitoring data and obtain all the mode components through empirical mode decomposition (EMD), denoise the mode components with noise using the wavelet threshold function to remove the noise components, select the optimal stratification for denoising the monitoring data of the Guozigou Bridge in Xinjiang in January 2023, determine the wavelet type and threshold selection criteria, and reconstruct the denoised intrinsic mode function (IMF) components to achieve accurate extraction of the effective signal. By referencing the deflection, temperature, and strain data of the Guozigou Bridge in Xinjiang in January 2023 and comparing the data cleaned by different mode decomposition and wavelet threshold denoising methods, the results show that compared with empirical mode decomposition (EMD)–wavelet threshold denoising and variational mode decomposition (VMD)–wavelet threshold denoising, the signal-to-noise ratios and root-mean-square errors of the four types of monitoring data obtained by the algorithm proposed in this study are the most ideal. Under the premise of minimizing reconstruction errors when processing a large amount of data, it has better convergence, verifying the practicality and reliability of the algorithm in the field of bridge health monitoring data cleaning and providing a certain reference value for further research in the field of signal processing. The computational method constructed in this study will provide theoretical support for data cleaning and analysis of nonstationary and nonlinear random signals, which is conducive to further promoting the improvement of bridge health monitoring systems. [ABSTRACT FROM AUTHOR]

Organic thioethers play an important role in the discovery of drugs and natural products. However, the green synthesis of organic sulfide compounds remains a challenging task. The convenient and efficient synthesis of 5-alkoxy-3-halo-4-methylthio-2(5H)-furanones from DMSO is performed via the mediation of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), affording a facile route for the sulfur-functionalization of 3,4-dihalo-2(5H)-furanones under transition metal-free conditions. This new approach has demonstrated the functionalization of non-aromatic Csp2-X-type halides with unique structures containing C-X, C-O, C=O and C=C bonds. Compared with traditional synthesis methods using transition metal catalysts with ligands, this reaction has many advantages, such as the lower temperature, the shorter reaction time, the wide substrate range and good functional group tolerance. Notably, DMSO plays multiple roles, and is simultaneously used as an odorless methylthiolating reagent and safe solvent. [ABSTRACT FROM AUTHOR]

An easy two‐/three‐component selective thioetherification of KSAc for the synthesis of a series of symmetrical/unsymmetrical 4‐alkylthio‐3‐halo‐2(5H)‐furanones has been described. The reaction without any metal catalyst or additive is carried out in air atmosphere at room temperature for 5 h, only using potassium thioacetate as an odourless sulfur source and a base simultaneously. The broad substrate scope and high yield make it important for the studies on both constructing C−S bond based on non‐aryl Csp2−X bond and synthesizing new 2(5H)‐furanone functional molecules. [ABSTRACT FROM AUTHOR]

A facile route for the synthesis of benzodisulfide heterocyclic compounds via a NaHCO3‐promoted three‐component reaction between 2‐halophenylacetic acids, elemental sulfur (S8) and amines under metal‐free conditions has been demonstrated. This transformation from available starting materials shows good functional group tolerance, and the target compounds can be derivatized for further application. [ABSTRACT FROM AUTHOR]

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To reduce the influence of nonlinear friction on the dynamic and static performance of gimbal axis for inertial stabilized platform, a novel method based on steady-state error response to identify LuGre friction parameters is proposed in this paper, and a kinetic friction torque testing system using the proposed method is developed. On account of the introduction of structure and electromechanical model for inertial stabilized platform, the relation among the input signals, interfering signals and steady-state error are analyzed. And then the torque ripple compensation function is identified and introduced into the control loop to eliminate the effects of torque ripple on parameter identification of friction model. Based on the friction torque testing system designed, the parameters of LuGre friction model for gimbal axis are got by the method of Two-step identification and dynamic parameter optimization. According to the identified friction model, the tracking process of the framework is compensated. The tracking performance is verified through both simulation and experimental results. [ABSTRACT FROM AUTHOR]