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Lithium and sodium metal anodes are plagued with non-uniform plating and vigorous chemical reactivity despite their high theoretical capacities and low working potentials. However, latest reports show that the coulombic efficiencies (CEs) and cycling lifespan of Na metal anodes are evidently superior to those of Li. Herein, we compare the plating/stripping processes of Li and Na metals and reveal that the lower CEs of Li are related to the fibrillary plating behavior originating from severer concentration polarization. It is found that fresh solid electrolyte interphases (SEIs) are continuously formed in association with the fibrillary growth of Li, thus reducing the CEs and consuming the electrolyte with cycling; however, the SEI reformation on Na is greatly suppressed as Na plating proceeds uniformly beneath the previously formed SEI, resulting in higher CEs. Consequently, Li exhibits a much more pronounced relationship of cycle life with the amount of the electrolyte than Na. Li can be cycled on bare Cu 550 times with 110 μL electrolyte. Furthermore, it is shown that the SEI on Li metal has a higher ion transport barrier compared with that on Na, and the concentration polarization at the electrode-SEI interface is responsible for the fibrillary plating of Li. This is proved by the inter-conversion in the geometry of Li and Na deposits when the concentration polarization is weakened for Li by increasing temperature and reinforced for Na by decreasing the sodium salt concentration. The CE of Li could be improved to 98.7% at 55 °C over 250 cycles. The mechanistic study in this work provides a suggestion to evaluate the reversibility of Li metal anodes more reasonably and a guidance to suppress concentration polarization and fibrillary growth, which may lead to highly reversible plating/stripping electrochemistry of Li and other metal anodes.

In this paper, chip recycled pressing process (CRP for short), a new method for recycling magnesium alloy chips, was put forward to prepare semi-solid billet. AZ91D magnesium alloy chips of different sizes were respectively recycled to prepare semi-solid billet by CRP process. Effect of chip size on compactness, microstructure and oxidation of CRP billet were investigated. And then CRP billet were heated to semi-solid state and its semi-solid microstructures were studied. The results showed that with the increase of chip thickness, grain refinement effect weakened, deformation uniformity aggravated and oxygen content of CRP billet decreased. Under the same CRP process conditions, the relative densities of four kind of CRP billet were 98.27%, 98.13%, 98.05% and 97.92%, respectively. Meanwhile, there was no significant difference in compactness and microstructure between them. Normally, oxygen content was not more than 1.8% and uniformly dispersed in CRP billet. Hence, the influence of size and deformation inhomogeneity of chip on compactness and microstructure of CRP billet were eliminated via CRP process. In CRP billet, microstructure and strain were uniform and this inherited during semi-solid isothermal treatment.

A drug-loaded membrane was prepared by electrospinning Polyε-caprolactone (PCL) with doxycycline hydrochloride (DOX) (15–25% w/w). Scanning electron microscopy (SEM) images revealed that fibrous average diameter decreased from247.16±57.61 nm to194.43±43.33 nm with the drug proportion increasing from 15% to 20% w/w, while there was no significant difference between 20% and 25% groups. The polymer matrix showed good encapsulation value (58–75%) for DOX, and the drug showed an amorphous manner in the polymer matrix. The agar diffusion test revealed that DOX-loaded membranes had an obvious inhibited effect onAggregatibacter actinomycetemcomitans(Aa) andPorphyromonas gingivalis(Pg), respectively. In vitro release test showed that DOX could persistently be released for a prolonged time more than 28 days, and the DOX level in the eluent steadied at 3–5 μg/mL which was all above the minimum inhibitory concentration (MIC) of DOX against Aa (0.125 μg/mL) and Pg (0.0625 μg/mL). Cytocompatibility, assessed in human periodontal ligament cells (hPLCs) by MTT-test and the morphology of cells on the surface of DOX-loaded membranes by SEM, indicated that all of the investigated nanofibrous membranes can be used to treat periodontal disease by integrating the GTR/GBR operation and antibiotic therapy. Above all, DOX-loaded nanofibrous membranes could have a persistent inhibited effect on periodontal pathogens to provide a relatively sterile environment for tissue repair and regeneration.

In this paper, chip recycling technology combined with SIMA method which is called CR-SIMA method was adopted to prepare semi-solid billets. AZ91D magnesium alloy was refined by Er and its microstructural evolution was investigated during semi-solid isothermal treatment. The results show that Er can improve the feature of cast structure and decrease the grain size. Moreover, the γ-Mg17Al12 phase is well refined and disperses in the α-Mg matrix. A semisolid microstructure with small and spheroidal primary particles can be obtained after partially remelting. With increasing heating temperature, the dissolution of eutectic Mg17Al12 phase first took place, resulting in the primary dendritic grains coarsening into interconnected non-dendritic grains. With heating continuously, the residual interdendritic γ-Mg17Al12 at the edges of the primary grains melted in succession and the primary grains separated into small polygon grains. During the semi-solid isothermal treatment, the amount of liquid increased until the solid-liquid system reached its equilibrium state. At the same time, owing to the decreasing of interfacial energy, the grains gradually spheroidized and began to grow with a further increasing of the holding time.

The strain-induced melt activation (SIMA) process is one form of the thixoforming for aluminum alloy. However, the non-uniform stress distribution restricts its application. In order to avoid this problem, a chip recycling strain-induced melt activation (CR-SIMA) process has been developed to prepare semi-solid billet. Microstructures of semi-solid ADC14 aluminum alloy billets heated to different temperatures and held for various times were investigated. The typical semi-solid microstructure with globular solid particles distributed in the liquid matrix is obtained in the temperature range of 560 and 565oC. The spheroidizing mechanism of ADC14 alloy prepared by the CR-SIMA process was studied. It was found that the severe deformation not only influences the solidification of spherical α-Al particles, but also affects the morphology of primary Si. The primary Si phases become tiny particles and distribute around the α-Al particles.

Based on micropolar fluid theory and micropolar solid elasticity theory, reflection and transmission characteristics of three kinds of micropolar elastic waves, which are longitudinal displacement wave and two coupled waves, were studied when incident longitudinal displacement wave propagated in micropolar fluid with micropolar elastic plate. Using numerical example, the variations of various amplitudes are also shown against the angle of incidence and the variation characteristics of various amplitudes are discussed. Results show that there exist maximum values of reflection and transmission coefficient for coupled wave, however, there exist minimum values of reflection coefficient for longitudinal displacement wave, and transmission coefficient decreases with the incident angle and the transmission coefficient are smaller for bigger incident angle.

CNC lathe spindle box is a key component of the CNC lathe system, and its dynamic characteristics are the main factor affecting the machining accuracy and processing efficiency of machine tools. In this paper, CK61125 CNC lathe spindle box model was established by simplifying its structure. Then modal analysis of the spindle box was done and extended to 6-order modes with the platform of co-simulation environment in ANSYS Workbench, and the natural frequencies and vibration modes for lathe spindle box were obtained. The weak links in the spindle box were found, and the improvement schemes are proposed. Finally the lathe spindle box was improved, the modal analysis of the spindle box was made again, and the results showed that the lathe spindle box dynamic performance was improved. All of these results are beneficial for optimization and re-design of the lathe spindle box so that it has better dynamic performance.

In order to enhance the actual effect of vibration aging on large lathe bed and optimize it, many technological parameters of vibration aging will be discussed in this paper, including exciting force, exciting frequency and exciting point, etc. Finite element method is used to analyze the casting stress distribution and natural mode of vibration of a large lathe bed. After the analysis, it is found that the distribution of the residual stress of the lathe bed is extremely uneven. By analyzing parameters of the natural vibration model and the exciting force as well as the exciting point, a reasonable parameter will be got when the lathe bed is vibrating. The “Selecting low-frequency to avoid torsion mode” which reduces the deformation to bed caused by the residual stress, was proposed. The parameters have been proved effective through experiment, and the proposed approach can be used in the research of vibratory stress relief.

In this paper, pure aluminium and Al-Cu (1%, 3% and 5% in mass fraction) alloy matrix composites reinforced with 35vol% 3Al2O32SiO2 short fibers were fabricated by a squeeze-casting technique. Interfacial structure and distribution of element of the composites were investigated by means of SEM, EPMA and TEM. The experimental results indicated that when pure aluminium was used as matrix, the interface was slick and chemical reaction occurred at the interface between amorphous SiO2 and matrix Al. When Cu element was added into the Al matrix alloy, the amorphous SiO2 on the fiber surface remained. Further more, with the increase of Cu element, the amount of the retained amorphous SiO2 increased. The interfacial reaction was inhibited due to the Cu element diffusion and enrichment towards the short fiber surface. SEM observation showed that large amount of fiber was drawn out from the matrix and some of them have been ruptured. Tensile test showed that the tensile strength of the 35vol% 3Al2O32SiO2sf/Al-Cu composite increased with the increasing of Cu content as compared with the Al2O3f/pure Al composite, the increment of the fracture strength of 3Al2O32SiO2sf/Al-Cu composite were 102%, 146% and 171%, respectively.

In this paper, pure aluminum and Al-Cu (1%, 3% and 5% mass.) alloy matrix composites reinforced with 40Vol% Al2O3-SiO2 sort fiber were fabricated by Squeeze-casting technique. Microstructure and tensile properties of the composites were investigated by means of SEM, EPMA, TEM and tensile tests. It was found from the experimental results that when pure aluminum, which was added into Cu elements, is used as matrix, chemical reaction occurred at the interface between amorphous SiO2 and matrix due to the Cu element diffusion and enrichment towards the sort fiber surface. Results indicated that with the increasing of Cu content the ultimate tensile strength decreased firstly then increased continuously.

The title compound, C18H24NO3+·Cl−·H2O, was synthesized by the reaction of propranolol hydrochloride with acetyl chloride in chloroform followed by slow evaporation in air. In the cation, the dihedral angle between the planes of the naphthalene ring system and the acetate group is 71.1 (2)°. An intramolecular N—H...O hydrogen bond results in the formation of a non-planar pseudo-ring, with the ether O and the H atom displaced by −1.328 (2) and 0.65 Å, respectively, from the plane of the other ring atoms. The cation and anion are linked by an N—H...Cl hydrogen bond. The water molecule is linked to a methyl H atom by C—H...O hydrogen bond.

Three 3d–4f heterometallic complexes, namely, [Co3Ln2(L)4(C2O4)2(H2O)2·6H2O]n (Ln = Pr (1), Nd (2), Sm (3); H2L = benzimidazole-5,6-dicarboxylic acid, H2C2O4 = oxalic acid), have been synthesized hydrothermally and characterized by single crystal X-ray diffraction study, IR, TGA and elemental analysis. The three complexes are isostructural; in their structures, the Co(II) centers are connected into a linear Co3 cluster by the C2O42− anions, the Ln(III) centers are connected into one-dimensional (1D) {Ln–O–C}n rod-like chains by the carboxyl groups of L2− anions, the linear Co3 clusters and {Ln–O–C}n rod-like chains are further connected by the L2− anions, and finally construct three 3D frameworks, which contain 1D channels along the b direction occupied by (H2O)8 clusters. In addition, magnetic studies of the three complexes all reveal antiferromagnetic behaviors.

In the title tetra­nuclear complex, [Cu4(C11H13NO4)4], which has crystallographic \overline{4} symmetry, the CuII ions are coordinated by the tridentate Schiff base ligands, forming a tetra­nuclear Cu4O4 cubane-like configuration. The CuII ion adopts a CuNO4 distorted square-pyramidal coordination environment. In the crystal structure, inter­molecular O—H⋯O bonds help to form a three-dimensional structure.