No abstract

Selective aerobic oxidation of biomass‐derived 5‐hydroxymethylfurfural (HMF) into high value‐added 2,5‐furandicarboxylic acid (FDCA) is regarded as one of the most attractive biomass transformations due to a wide range of its application prospects, particularly as an important renewable alternative to petroleum‐derived terephthalic acid in the synthesis of useful polymers. Herein, a novel MnOx−CeO2 (MC) supported palladium catalyst was synthesized and applied for the aerobic oxidation of HMF into FDCA in KHCO3 aqueous solution. The physical and chemical properties of the obtained catalysts were systematically characterized by TEM, N2 adsorption and desorption, XRD, TG, XPS, and H2‐TPR characterization methods. And the highest yield of FDCA at 92.5 % was achieved under the optimal reaction conditions. Moreover, regeneration tests revealed the synthesized Pd/MC catalyst can be recovered and reused at least five times without significant loss of catalytic activity. The developed facile reaction system with Pd/MC catalysts offers a new route to large‐scale and economically viable processes for the oxidation of HMF into FDCA.

For multi-stage pumps, the change of the impeller stage spacing will have a greater impact on the dynamic characteristics of the shafting rotor. The paper took XBC18-178-240LC3 vertical long shaft fire pump as the research object, using ANSYS Workbench software to study the relationship between the critical speed of the shafting rotor and the different positions of the impellers. First, 9 shafting rotors (based Z4,Z5 and Z6 models) under the different positions of the impellers were established; and then the change law of the critical speed on 9 shafting rotors in the first 12 modes was studied. The results showed that different positions of the impeller on the shaft have a great impact on critical speed of the shafting rotor. With the increase of the distance between the impeller stages, the low-order critical speed (6th order and within) of the Z4 model shafting rotor decreases. However, the low-order critical speed (5th order and within) of the Z5 and Z6 model shafting rotors decreases with the increase of the distance between the impeller stages, and the high-order critical speed doesn’t satisfy this law. Considering static characteristics of the shafting rotor and actual engineering applications, the paper selected the Z5-stage spacing 800mm shafting rotor model as the best case, providing a theoretical support for the subsequent vertical long shaft fire pump design optimization.

In the new media era, the convenience, speed, and low access threshold of the Internet provide channels and access to women's originally compressed discourse, releasing women's discourse to a certain extent. This paper focuses on the manifestations of women's discourse being liberated in the new media context, what problems still exist, and provides relevant strategies to solve them. The purpose of this paper is to reveal the innovations, difficulties, and breakthrough methods of women's discourse in the development of the Internet, and to provide references for subsequent research. This paper will discuss and study women's discourse as the main research object through literature analysis, typical case analysis, and data comparison of previous reports. It can be concluded that although women's discourse has been developed and expanded in the new media environment, it is still suffering from problems such as patriarchal social gaze and alienation of self-expression, which need improvement from multiple parties such as media, society, and women themselves to improve.

In this paper, a vertical long-shaft fire pump XBC18-178-240LC3 was taken as the research object to study the static characteristics of the pump rotor-shaft system under different shaft length connection. To analyse the influence of the length and number of the intermediate shaft section of the pump shaft on the deformation and equivalent stress of the shafting rotor, three shafting rotor models Z4(modified model), Z5(original model) and Z6(modified model) were designed, and then the static characteristics of them were analysed and compared under four operating conditions of 0.65Q d(0.65 times design flow),1.0Q d, 1.2Q d and 1.4Q d by numerical simulation. The results suggested that the changed rules of the three models' deformation and equivalent stress were basically the same. After the rated operating condition, the maximum deformation of the impeller of Z5 model was smaller than that of the Z4 and Z6 models. Under the four operating conditions, the maximum equivalent stress of the impeller of Z5 model was the smallest. This showed that the length and number of the intermediate shaft section affected the deformation and equivalent stress of the shaft rotor. Therefore, Z5 model was selected as the best rotor structure design scheme.