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The flat torque‐angle characteristic of torque motor plays a decisive role in the control quality of electro‐hydraulic servo and proportional valve. To solve the issue that the current wet‐type torque motor for two‐dimensional (2D) valve does not have flat torque‐angle characteristic, a method for adjusting the flat torque‐angle characteristic of torque motor for 2D valve based on magnetic saturation of tooth tip is proposed. Taking the current limited angle torque motor with rectangular tooth (TM‐R) as an application example, the rectangular teeth on the stator are replaced by sharp teeth to form a novel torque motor with sharp tooth (TM‐S), and the flat torque‐angle characteristic can be obtained by constructing magnetic saturation of tooth tip. The variation trends of magnetic permeance in each magnetic saturation region of the tooth tip are analyzed. The torque‐angle characteristics of TM‐S and TM‐R under different control currents are compared. Prototypes of TM‐S and TM‐R with optimized parameters are designed and manufactured, and special experimental benches are built for static and dynamic test. Experimental results are basically consistent with the theoretical analysis. The comparative study shows that the torque‐angle characteristic of TM‐R is a downward curve, while the torque‐angle characteristic of TM‐S is an approximate flat curve. The research validates the effectiveness of the proposed method, which can both realize the flat torque‐angle characteristic and improve the dynamic response of torque motor. Finally, the proposed method can be further applied to other rotary and direct‐acting electro‐mechanical converter (EMC) with multi‐tooth structure. [ABSTRACT FROM AUTHOR]

Strong and tough bio‐based fibers are attractive for both fundamental research and practical applications. In this work, strong and tough hierarchical core–shell fibers with cellulose nanofibrils (CNFs) in the core and regenerated silk fibroins (RSFs) in the shell are designed and prepared, mimicking natural spider silks. CNF/RSF core–shell fibers with precisely controlled morphology are continuously wet‐spun using a co‐axial microfluidic device. Highly‐dense non‐covalent interactions are introduced between negatively‐charged CNFs in the core and positively‐charged RSFs in the shell, diminishing the core/shell interface and forming an integral hierarchical fiber. Meanwhile, shearing by microfluidic channels and post‐stretching induce a better ordering of CNFs in the core and RSFs in the shell, while ordered CNFs and RSFs are more densely packed, thus facilitating the formation of non‐covalent interactions within the fiber matrix. Therefore, CNF/RSF core–shell fibers demonstrate excellent mechanical performances; especially after post‐stretching, their tensile strength, tensile strain, Young's modulus, and toughness are up to 635 MPa, 22.4%, 24.0 GPa, and 110 MJ m−3, respectively. In addition, their mechanical properties are barely compromised even at −40 and 60 °C. Static load and dynamic impact tests suggest that CNF/RSF core–shell fibers are strong and tough, making them suitable for advanced structural materials. [ABSTRACT FROM AUTHOR]

Microbubbles were applied for the first time to enhance the aqueous biphasic hydroformylation of long‐chain alkenes. The gas–liquid–liquid multiphase hydroformylation was carried out using 1‐dodecene as model higher olefin and dihexadecyl dimethyl ammonium bromide (DDAB) as surfactant. The increasing liquid temperature resulted in the increased mean bubble size and total bubble number, but this trend became inapparent at high temperatures due to the reduced liquid viscosity. The increasing gas flow rate was favorable to increase the multiphase interfacial area, thus leading to the increasing mass transfer coefficient KLa. The conversion of 1‐dodecene reached maximum 95% in the three‐phase microemulsion system, and at a gas flow rate of 40 ml min−1. Further increasing the gas flow rate to 80 ml min−1 decreased the conversion, which was attributed to the destroyed flow field, as observed in micro‐PIV. Owing to the increased multiphase mass transfer efficiency, the application of microbubbles allowed to intensify the hydroformylation reaction with reduced reaction pressure, higher chemoselectivity, and increased turnover frequency (TOF). [ABSTRACT FROM AUTHOR]

The solubility of 1,1-diamino-2,2-dinitroethylene (FOX-7) in four binary mixed solvents (Dimethyl sulfoxide + Acetonitrile, Cyclohexanone, 1,2-Dichloroethane, 2-Propanol) was determined by using a laser dynamic method at temperatures from 293.15 to 333.15 K under 0.1 MPa. The measured results showed that the experimental solubility of FOX-7 increased with increasing temperature and Dimethyl sulfoxide content in the studied mixture solvents. Solubility data were well correlated by the modified Apelblat model, Yaws model and van't Hoff model, and the modified Apelblat model has the lowest root-mean-square deviation and can be used as the optimal model for data fitting. In addition, the thermodynamic parameters of the dissolution process, the surface tension, and surface entropy factor of FOX-7 were calculated based on the experimental data, which provided basic data for the optimization of crystallization process and industrial amplification of FOX-7. The cooling crystallization experiments were carried out in the investigated mixed solvents. The crystal morphology of FOX-7 obtained in the Dimethyl sulfoxide + Cyclohexanone mixed solvent (xDMSO = 0.3266) was regular, spherical, uniform in particle size, and have better thermal stability. Cyclohexanone could be the excellent non-solvent in the sphericalization of FOX-7. [ABSTRACT FROM AUTHOR]