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Abstract A new synthesis route different from convenient epoxy/C[O.sub.2] method was established to synthesize a five-membered dicyclocarbonate of bisphenol A (BisA-5dCC), and its hybrid non-isocyanate polyurethanes with epoxy resins (HNIPUs) [...]

Patients with high neuroticism are more likely to have negative perceptions of disease and to report more depressive symptoms. The important environmental factor of patient-physician trust may buffer the negative effect of neuroticism on illness perception and thereby help to protect patients' mental health. This study examined the roles of illness perception and patient-physician trust in the relationship between neuroticism and patients' depressive symptoms. A cross-sectional survey was administered to patients of two Chinese hospitals (N = 384). The findings indicated that higher neuroticism was directly associated with depressive symptoms and indirectly associated with depressive symptoms via negative illness perception. Importantly, only the benevolence dimension of patient-physician trust was shown to moderate the indirect relationship between neuroticism and depressive symptoms: compared with patients in the low-level benevolence group, patients with high neuroticism in the high-level benevolence group reported less negative illness perceptions and, in turn, reduced depressive symptoms. The technical competence dimension of patient-physician trust showed no such moderating effect. For patients with high neuroticism, future interventions aimed at changing illness perceptions should focus not only on demonstrating technical competence and improving symptoms, but also on providing healthcare information and affectionate social support., Author(s): Qian-Feng Li [sup.1] , Qian-Wen Ma [sup.2] , Chao-Hui Zhu [sup.2] , Jian-Bin Chen [sup.3] , Shun-Wei Liang [sup.2] , Cheng-Cheng Cai [sup.2] , Jing-Bo Zhao [sup.2] [sup.3] [sup.4] [...]

In the process of deep geological disposal of high-level radioactive waste, the decay of nuclide will generate a large amount of heat, which is released into the surrounding environment and affects the water-rock interaction of the deep geological environment. In order to explore the impact of temperature on the chemical environment of the deep groundwater in the Xinchang site, the undisturbed groundwater and deep granite samples at the Xinchang site were used to carry out water-rock interaction study at different temperatures. The research results show that the granite sample from borehole BS34 reacts with the undisturbed groundwater. The final pH value of the aqueous phase is between 6.4-8.5, and the TDS is between 1 653.9-1 759.6 mg/L. With the increase in temperature of the reaction system, the concentrations of Na+ and K+ in the aqueous phase increase, resulting from the dissolution of albite and cation exchange for Na+, and the dissolution of K-feldspar for K+, respectively. Meanwhile, the concentrations of Ca2+, Mg2+ and HCO-3 decrease, mainly due to the precipitation of calcite and dolomite. The higher the reaction temperature, the more calcite and dolomite are precipitated.

Diels-Alder (DA) addition is an efficient method to repair damages at mild conditions. It is often used in self-healing polyurethanes and epoxy resins and seldom used in cross-linked polyamides (cPAs). Michael addition becomes a useful method to synthesize cPAs. However, no efficient way has been established to conduct double-addition of primary amines. In this work, organic catalyzed Michael addition and polycondensation were established to prepare polyamide oligomers with furan pendent groups (pFU-PAs), and a DA addition was adopted to prepare self-healing cross-linked polyamides (SH-cPAs). A bulk double Michael addition of furfurylamine and methyl acrylate was performed at 30-70[degrees]C in the presence of 1,5,7-triazabicyclo[4.4.0] dec-5-ene (TBD), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), or 4-(N,N-dimethylamino) pyridine (DMAP), and a high yield of furfurylamine-N,N-bis(methyl propionate) (FA-BMP) was prepared. The catalytic activity order is MTBD>TBD >> DMAP in Michael addition. Melt polycondensation of FA-BMP with bis(2-aminopropyl) polypropyleneglycol and hexamethylene diamine was catalyzed by MTBD and N,N'-diphenylthiourea. The DA addition of 1,5-bismaleimido-2-methylpentane and pFU-PAs was monitored by FT-IR, [sup.1]H NMR, DSC, polarizing optical microscopy, and gel content. In these catalyzed processes, the structures of FA-BMP, pFU-PAs, and SH-cPAs were controlled easily, and the SH-cPAs showed good mechanical property and excellent self-healing performance of 88%-98%. KEYWORDS Diels-Alder addition, Michael addition, organic catalysts, polycondensation, self-healing polyamides, 1 | INTRODUCTION Thermoset polymers have a three-dimensional cross-linked structure, and they exhibit remarkable advantages, such as solvent resistance, heat resistance, dimensional stability, and excellent mechanical properties. [1-3] During their [...]

A simple and green method was established to prepare self-healing crosslinked nonisocyanate polyurethanes (SH-cNIPUs) from biobased diglycerol bis(cyclic carbonate) (DGDC). Two nonisocyanate polyurethane prepolymers with furan terminal groups (tFU-NIPUs) were synthesized through a ringopening reaction of DGDC with furan methylamine and trimethylolpropane tris(poly[propylene glycol], amine terminated) ether, or tris(2-aminoethyl) amine under mild conditions. The SH-cNIPUs were prepared via a Diels-Alder reaction between tFU-NIPUs and a bismaleimide. SH-cNIPUs were characterized by ATI-FTIR, 'H NMR, differential scanning calorimetry, polarized optical microscope, and tensile strength after being damaged and healed. SH-cNIPUs with glass transition temperature from 8 to 49[degrees]C, tensile strength up to 21 MPa, and self-healing efficiency from 67 to 80% were successfully synthesized. KEYWORDS biobased, Diels-Alder reaction, nonisocyanate route, self-healing polyurethanes, 1 | INTRODUCTION Cross-linked polymers are used widely in our daily lives and in different industrial fields due to their dimensional stability and excellent mechanical properties. However, cross-linked polymers have [...]

The high-speed train transmission system is a complex electromechanical coupling system. In this study, the torsional vibration of a train transmission system was studied. The centralised mass model of the mechanical structure of the coupling system was established. The natural vibration characteristics of the mechanical mechanism system were analysed. The results show that the natural vibration frequency of the universal shaft was 4.08 Hz, the natural vibration frequency of the pinion was 7.24 Hz, the natural vibration frequency of the big gear was 35.6 Hz, and the natural vibration frequency of the wheelset was 107.48 Hz. The traction motor model was built, and by considering the electromechanical coupling of the system, a torsional vibration suppression strategy for harmonic components in the motor is proposed. The effectiveness of the suppression strategy was verified by MATLAB/Simulink model simulation.

This article presents a convenient method for synthesizing segmented poly(ether ester amide)s (PEEAs) by polycondensation and chain extension. A nylon-6 oligomer prepared from ζ-caprolactam and ethanolamine through ring-opening polymerization was polymerized with adipic acid and diglycol to prepare PEEA prepolymers (PrePEEAs) with ether linkages and amide contents ranging from 20 to 60 mol%. Chain extension of the PrePEEAs was conducted at 200°C using 2,2'-(1,4-phenylene)-bis(2oxazoline) and carbonyl biscaprolactamate as combination chain extenders. The chain-extended PEEAs (ExtPEEAs) were characterized by viscometry, gel permeation chromatography, FT-IR, ¹H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray diffraction, and tensile testing. Results show that incorporation of nylon-6 segments yields semicrystalline ExtPEEAs and that introduction of ether linkages improves the flexibility of the resultant polymers. ExtPEEAs showed [T.sub.m] from 107.6 to 137.3°C, good thermal stability with initial decomposition temperatures above 337.3°C, and tensile strengths of up to 27.4 MPa with strains at break ranging from 231.24 to 1052.52%., INTRODUCTION Polyesters and polyamides are important industrial polymers. Aliphatic polyesters, such as poly(butylene succinate) (PBS), polyl(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV), and polylactic acid (PLA), have become important commercial polymers because of their [...]