Search

Purposes The bimetallic modified Y zeolite is of great importance for the deep removal of thiophene in coking benzene. The influence of metal ion-exchange sequence on the desulfurization performance of zeolite is crucial. Methods A series of bimetallic modified sorbents were prepared by ion-exchange with Cu and Ce. The desulfurization performance of sorbents in thiophene-benzene solutions was evaluated by static adsorption experiments. The physical and chemical properties of sorbents were analyzed by XRD, Py-FTIR, XPS, H2-TPR, and N2 adsorption and desorption techniques. Findings The results show that metal ion-exchange sequence affects the relative crystallinity, ion-exchange degree, metal content, and L acid amount of sorbent. The correlations between the physical, chemical properties and the desulfurization performance of sorbent indicate that the higher the ion-exchange degree, the higher the desulfurization efficiency of sorbent. Meanwhile, the more Cu＋ and Ce4＋ in the sorbent, the more L acid sites formed and the higher its desulfurization efficiency. When Y zeolite is exchanged by Ce first and then Cu, the metal Ce affects the location of Cu and improves reduction performance of Cu. The desulfurization efficiency order of sorbents is CuCeY>CeCuY>Cu-CeY. The desulfurization efficiency of CuCeY is the highest, reaching 97.3%, and its relative crystallinity is the highest and ion-exchange degree is the largest. This work serves as a guide for the preparation of high efficiency desulfurization sorbents.

When exposed to corrosive environments, metals, which are relatively common industrial materials, undergo serious corrosion, leading to significant economic losses. Therefore, studying the corrosion rate of metals in their early stages holds great pedagogical significance. This study employs a standard specimen of 20# steel as an experimental object, designing the experimental teaching of metal corrosion rate under varying temperatures, PH levels, and hydrated salt materials. The weightlessness method determines the overall corrosion rate of the metal, while the electrochemical method determines the localized corrosion rate of the metal. When the experimental temperature is 80℃ and 100℃, the corrosion rate of 20# steel is the largest; both are 0.00800g·m−2·d−1, and the charge transfer resistance increases gradually when the temperature is −20℃~5℃, and decreases gradually when the temperature is 5℃~100℃. The corrosion rate of the metal did not change much at pH=7 and 8, and the corrosion rate reached 0.688 mm/a, and the impedance curve polarization resistance Rp was the smallest when pH=5, and its corrosion resistance was poor under acidic conditions. The average corrosion rates in MgSO4·7H2O, and CaCl2·6H2O and Ba(OH)2·8H2O were 0.0030g/m−2h−1, 0.0018g/m−2h−1, and 0.0050 g/m−2h−1, respectively. Teaching experiments were used to carry out the present study. The study aims to let students experience the process of metal corrosion through teaching experiments and better help them solve cognitive difficulties in metal corrosion.

Cu6Sn5-xAg alloys (x = 0, 3, 6; %, mass fraction) were synthesized using Ag as a dopant through a high-temperature melting technique. The microstructure of the alloy was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and other equipment, while the hardness of the alloy was measured to investigate the impact of Ag addition on the structure and microstructure of the Cu6Sn5 intermetallic compound. This study explored the influence of varying Ag contents on the properties of Cu6Sn5 intermetallic compounds, with calculations based on first principles revealing the mechanical properties and density of states of η′-Cu6Sn5 and its Ag-doped systems. The results indicated that Cu6Sn5-xAg alloys predominantly existed in three distinct forms, all exhibiting large masses without any impurities or precipitates. First-principle calculations demonstrated that Ag substitution in certain sites suppressed the anisotropy of the Young's modulus of Cu6Sn5, particularly in the Cu1, Cu3, Sn1, and Sn3 positions, while the effect was less significant at the Cu2, Cu4, and Sn2 sites. The introduction of Ag through doping enhanced the covalent bonding within the η′-Cu6Sn5 structure, promoting the formation of a stable (Cu, Ag)6Sn5 structure. [ABSTRACT FROM AUTHOR]

A new type of special machine tool for stripper sleeve was developed according to the stripper sleeve process of composite board. In order to ensure the reliability of the mainframe structure and the performance of the linear guide mechanism, the static structural analysis and modal analysis of the mainframe are carried out. The results show that the maximum stress of the supporting beam under the main frame is about 48.18 MPa, the maximum strain is 0.00023, and the maximum stress of the four-legged column is about 5.35 MPa, which is full of strength and stiffness design requirements. The end-cutting mechanism is installed on the beam through the installation plate. The deformation of the beam has a great influence on the operation accuracy of the linear guide mechanism and the cutting accuracy of the end-cutting mechanism. The maximum displacement in the X and Y directions of the installation plate is 0.014 mm, 0.030 mm and 0.197 mm, respectively, which meets the normal use requirements and cutting accuracy requirements of the linear guide mechanism. The first six natural frequencies of the mainframe are 2.963 – 47.137 Hz. In order to make the mainframe have good dynamic characteristics, avoid resonance and meet the end-cutting requirements of the composite board, the motor speed should be controlled between 300 – 493 r / min.

It was to adopt magnetic resonance imaging (MRI) combined with computed tomography (CT) to diagnose multiple myeloma (MM) and evaluate the therapeutic effect of the doxorubicin nano-drug delivery system on MM, providing a more effective method for the treatment of MM. For this aim, eighty-eight patients with MM admitted to our Hospital from June 2019 to July 2020.7 were selected as study subjects and divided into a control group (treated with doxorubicin) and an observation group (treated with doxorubicin-loaded nanoparticles) according to the random number table, 44 cases for each group. MRI and CT were used to examine the two groups of patients to assess the clinical efficacy and side effects of the two treatments and to compare the myeloma cell survival rate and apoptosis rate. Results showed that the diameter of nanoparticles was about 50 nm, the particle size was uniform, the distribution was dense, and the stability was good; the lesion was well-circumscribed on CT scan, and a soft tissue mass could be detected on MRI. The number of patients with effective treatment in the observation group was significantly higher than that in the control group (42 cases vs 34 cases) (P< 0.05); the number of patients with small plate reduction, increased myocardial enzymes, alopecia, liver failure, gastrointestinal reactions, peripheral neuritis, and other adverse reactions in the observation group was significantly lower than that in the control group (total number of patients 48 vs 101) (P< 0.05); the survival rate of myeloma cells in the observation group was obviously inferior to that in the control group (61.3 % vs 88.31 %) (P< 0.05). Conclusion: MRI combined with CT examination can be better used for the diagnosis of the disease, and the study shows that doxorubicin nano-drug delivery preparation is safer and more effective in the treatment of MM disease, which is worthy of clinical promotion.