Information system development in the small firm

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Effect of Cu-Doped Carbon Quantum Dot Dispersion Liquid on the Lubrication Performance of Polyethylene Glycol

Energy saving and reduced consumption of key materials such as bearings in high-end equipment can be realized by synthesizing a new lubricating functional additive, copper-doped carbon quantum dot dispersion liquid (Cu-CQDs) via hydrothermal reaction with glycerol, cupric chloride dihydrate, and choline chloride as raw materials. The influence of the dispersion liquid containing Cu-CQDs nanoparticles on the lubricating properties of polyethylene glycol (PEG200) was investigated on a four-ball friction tester. The wear scars of steel balls after friction were analyzed using a scanning electron microscope accompanied by energy dispersive spectroscopy (SEM/EDS), photoelectron microscopy, and Raman spectroscopy. The results revealed the friction and wear mechanism of Cu-CQDs. Cu-CQDs dispersion liquid can significantly enhance the lubrication performance of PEG. The average friction coefficient of PEG containing 2.0 wt% Cu-CQDs dispersion liquid was 40.99% lower than that of pure PEG. The friction and wear mechanism can be ascribed to friction, inducing Cu-CQDs to participate in the formation of boundary lubricating film, resulting in a low friction coefficient and wear scar diameter

Novel Synthesis of Cu‐Schiff Base Complex@Metal‐Organic Framework MIL‐101 via a Mild Method: A Comparative Study for Rapid Catalytic Effects

Abstract The use of metal complex immobilized/decorated porous materials as catalysts has found various applications. As such, finding a new and mild method for synthesis of metal complex immobilized over porous material is of great interest. Immobilized porous materials for styrene oxidation were reported in this work. Immobilized porous material of Cu‐Schiff base complex @MIL‐101 were described, in which immobilized Cu‐Schiff base complex within super cage of a metal‐organic framework (MOF)‐based porous material, chromium (III) terephthalate MIL‐101. They were systematically characterized by using elemental analysis, powder X‐ray diffraction, fourier transform infrared spectroscopy, N2 absorption‐desorption, and so on, also used as catalyst for the selective oxidation of styrene to benzaldehyde. Comparatively, the immobilized heterogeneous catalyst of Cu‐Schiff base complex@MIL‐101 acted as an efficient heterostructure catalyst in the oxidation of styrene to benzaldehyde up to six cycles, and showed superior activity for styrene oxidation over MIL‐101

Understanding of the Structural Chemistry in the Uranium Oxo-Tellurium System under HT/HP Conditions

The study of phase formation in the U-Te-O systems with mono and divalent cations under high-temperature high-pressure (HT/HP) conditions has resulted in four new inorganic compounds: K2[(UO2)(Te2O7)], Mg[(UO2)(TeO3)2], Sr[(UO2)(TeO3)2] and Sr[(UO2)(TeO5)]. Tellurium occurs as TeIV, TeV, and TeVI in these phases which demonstrate the high chemical flexibility of the system. Uranium (VI) adopts a variety of coordinations, namely, UO6 in K2[(UO2)(Te2O7), UO7 in Mg[(UO2)(TeO3)2] and Sr[(UO2)(TeO3)2], and UO8 in Sr[(UO2)(TeO5)]. The structure of K2[(UO2)(Te2O7)] is featured with one dimensional (1D) [Te2O7]4- chains along the c-axis. The Te2O7 chains are further linked by UO6 polyhedra, forming the 3D [(UO2)(Te2O7)]2- anionic frameworks. In Mg[(UO2)(TeO3)2], TeO4 disphenoids share common corners with each other resulting in infinite 1D chains of [(TeO3)2]4- propagating along the a-axis. These chains link the uranyl bipyramids by edge sharing along two edges of the disphenoids, resulting in the 2D layered structure of [(UO2)(Te2O6)]2-. The structure of Sr[(UO2)(TeO3)2] is based on 1D chains of [(UO2)(TeO3)2]∞2− propagating into the c-axis. These chains are formed by edge-sharing uranyl bipyramids which are additionally fused together by two TeO4 disphenoids, which also share two edges. The 3D framework structure of Sr[(UO2)(TeO5)] is composed of 1D [TeO5]4− chains sharing edges with UO7 bipyramids. Three tunnels based on 6-Membered rings (MRs) are propagating along [001], [010] and [100] directions. The HT/HP synthetic conditions for the preparation of single crystalline samples and their structural aspects are discussed in this work