Using water separation technique, acrylic acid (AA) and polyethylene glycol (PEG) 1000, of which the ratio was 1.5, were esterified and the optimum esterification ratio of 90% could be reached under the condition of 110 ℃×3 h. Using polyoxyethylene acrylate macromonomer (PA) prepared in the esterification, AA and sodium methylacryl sulfonate (MAS) as monomers, a copolymer which could be used as superplasticizer was prepared by free radical copolymerization in n(PA)∶n(AA)∶n(MAS) of 1∶7∶3. When the synthesis condition was 80 ℃× 5 h, the optimal dosage of initiator was 3.0%-4.0%, the fluidity of cement paste with the samples could reach 270 mm. By analyzing the effect of the content of residual small molecule sulfonic monomer on the properties of sample, n(MAS)/n(PA) was controlled in a range of 2.5-3.8.

This article investigated how collectivism-oriented human resource management can influence on innovation performance through team reflexivity and team psychological safety. Using a sample of 200 research-oriented teams in Chinese universities, the empirical results clearly indicate that collectivism-oriented human resource management is beneficial to teams’ innovation performance. The results of the mediating model show how team reflexivity and team psychological safety mediate the relationship between collectivism-oriented human resource management and innovation performance. The implications for researchers and practitioners are also discussed.

High-dimensional high-frequency continuous-vibration control problems often have very complex dynamic behaviors. It is difficult for the conventional control methods to obtain appropriate control laws from such complex systems to suppress the vibration. This paper proposes a new vibration controller by using reinforcement learning (RL) and a finite-impulse-response (FIR) filter. First, a simulator with enough physical fidelity was built for the vibration system. Then, the deep deterministic policy gradient (DDPG) algorithm interacted with the simulator to find a near-optimal control policy to meet the specified goals. Finally, the control policy, represented as a neural network, was run directly on a controller in real-world experiments with high-dimensional and high-frequency dynamics. The simulation results show that the maximum peak values of the power-spectrum-density (PSD) curves at specific frequencies can be reduced by over 63%. The experimental results show that the peak values of the PSD curves at specific frequencies were reduced by more than 47% (maximum over 52%). The numerical and experimental results indicate that the proposed controller can significantly attenuate various vibrations within the range from 50 Hz to 60 Hz.

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The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to the differences of chain sections, functional groups, etc, polyacrylic acid superplasticizer could be divided into A, B, C three parts. Among them, A chain section included sulfonic acid groups, B chain section carboxyl groups, C chain section polyester. Polyacrylic acid superplasticizers with different matching of A, B, C chain sections, different length of C chain section and different molecular weights were synthesized by acrylic acid, polyethylene glycol, sodium methyl allylsulfonate; the relation between the molecular structure and performance was also studied. The expetimental results indicate that the water-reduction ratio increases obviously with the increment of the proportion of sodium methyl allylsulfonate chain section in the molecular; the slump retention increases greatly with the increment of the proportion of acrylic acid chain section; the dispersion of cement particles increases with the increment of the chain length of polyethylene glycol; when the molecular weight is in the range of 5000, the dispersion and slump retentibity increase with the increment of the average molecular weight of polymers.