Search

We developed a lithium ion conductor in Li 4 SiO 4 -Li 3 PO 4 -LiBO 2 ternary ceramic system comprising of the mole ratio as Li 4 SiO 4 :Li 3 PO 4 :LiBO 2 = 60:40:20 (termed as 40LP + 20B), exhibiting the ion conductivity of 5.7 × 10 − 6 s/cm at room temperature. From the X-ray diffraction patterns, the ternary solid solution has the orthorhombic phase structure with the increased unit cell volume due to the substitution of boron in lattice. The SEM images show that the high densification of the 40LP + 20B samples sintered at 900 °C for 6 h, and EDS mappings illustrate that the incorporating boron is distributed homogenously in the grains and no precipitated impurity was observed on grain surface or around grain boundaries. The data of electrochemical impedance spectroscopy (EIS) reveal the low resistance from grain boundary, giving rise to the high bulk ion conductivity. The lithium ion conductor in Li 4 SiO 4 -Li 3 PO 4 -LiBO 2 system is of great potential as practical solid electrolyte for all-solid-state battery. [ABSTRACT FROM AUTHOR]

Freestanding single-crystal complete nanorings of zinc oxide were formed via a spontaneous self-coiling process during the growth of polar nanobelts. The nanoring appeared to be initiated by circular folding of a nanobelt, caused by longrange electrostatic interaction. Coaxial and uniradial loop-by-loop winding of the nanobelt formed a complete ring. Short-range chemical bonding among the loops resulted in a single-crystal structure. The self-coiling is likely to be driven by minimizing the energy contributed by polar charges, surface area, and elastic deformation. Zinc oxide nanorings formed by self-coiling of nanobelts may be useful for investigating polar surface — induced growth processes, fundamental physics phenomena, and nanoscale devices. [ABSTRACT FROM AUTHOR]

Indium oxide nanobelts of growth directions of [100] type (majority) and [120] type (minor) have been found. The two types of nanobelts have the top and bottom surfaces being (001), while the [100] type nanobelts have side surfaces of (010) and a rectangular cross-section, and the [120] type nanobelts have a parallelogram cross-section. The nanobelts have a perfect crystal structure without the presence of line or planar defects. [Copyright &y& Elsevier]

Abstract: A microwave-assisted hydrothermal approach combined with carbothermal reduction has been developed to synthesize monodisperse porous LiFePO4/C microspheres, which possess the diameter range of 1.0–1.5 μm, high tap density of ∼1.3 g cm−3, and mesoporous characteristic with Brunauer–Emmett–Teller (BET) surface area of 30.6 m2 g−1. The obtained microspheres show meatball-like morphology aggregated by the carbon-coated LiFePO4 nanoparticles. The electrochemical impedance spectra (EIS) results indicate that carbon coating can effectively enhance both of the electronic and ionic conductivities for LiFePO4/C microspheres. The Li-ion diffusion coefficient of the LiFePO4/C microspheres calculated from the cyclic voltammetry (CV) curves is ∼6.25 × 10−9 cm2 s−1. The electrochemical performance can achieve about 100 and 90 mAh g−1 at 5C and 10C charge/discharge rates, respectively. As cathode material, the as-prepared LiFePO4/C microspheres show excellent rate capability and cycle stability, promising for high power lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: The heat treatment of silicon nitride ceramics with only CeO2 as a sintering additive was carried out at different temperatures. Large residual stress was induced only by the non-relaxed volume changes and not by the relaxed volume changes (i.e. the crystallized phases with cavities or microcracks). The fact that the liquid formation temperature of the Si–Ce–O–N system (∼1470°C) is much lower than that of the Si–Yb–O–N system (∼1650°C) is the reason why the residual stress is comparable almost to each other in CeO2-doped Si3N4, but increases steadily with heat-treatment temperature in Yb2O3-doped Si3N4. The large residual stress and the induced cavities and microcracks are the dominant factors for the reduction in room-temperature strength of the heat-treated samples. The defects in β-Si3N4 grains of heat-treated samples were caused by the large residual stress, and may lead to the reduction of both room- and high-temperature strengths. These results significantly extends our previous study (Guo GF, Li JB, Yang XZ, Lin H, Liang L, He MS, Tong XG, Yang J. Acta Mater 2006;54:2311) on heat-treated Si3N4 ceramics with only Yb2O3 (one of the heavier lanthanide oxides) as a sintering additive. [Copyright &y& Elsevier]

A novel heterostructured multilayer thin-film solid electrolyte consisting of LiON-AlO x was synthesized by atomic layer deposition (ALD). The ALD-derived films were grown about 200 °C on SiO 2 /Si substrate by an alternating deposition of lithium oxynitride (LiON) and AlO x sublayers with 1–6 nm thickness and then characterized by various methods for roughness, homogeneity, crystallinity, thickness, composition, chemical environment, and ionic conductivity. The desired layer-by-layer structure of the films was confirmed by both high-resolution transmission electron microscopy and time-of-flight secondary ion mass spectrometry. Compared to pure LiON films without insulating AlO x interlayers, the ionic conductivities of multilayer LiON-AlO x films with various nanoscale sublayers are enhanced due to channeling effects between the heterointerfaces of nanoscale sublayers, while the activation energies are increased due to the incorporation of non-conducting AlO x sublayers. Thickness-dependent conductivity of the multilayer LiON-AlO x films indicates that 3.2 nm of LiON sublayer alternatively combined with 1 nm AlO x sublayer has the best conduction performance. The film with 15 bilayers exhibits a conductivity of 6.2 × 10−4 S/cm at 160 °C with an activation energy of 0.57 eV. • Thin-film LiON-AlO x heterostructures are prepared by atomic layer deposition • Films are characterized by SEM, TEM, XPS, and ToF-SIMS • Conductivity along the films is measured by impedance spectroscopy • Conductivity of LiON films is enhanced by incorporation of insulating AlO x layers [ABSTRACT FROM AUTHOR]

Lung cancer is difficult to diagnose, has a high mortality rate and a high recurrence rate. By grouping and analyzing the gene expression in lung cancer samples, we selected the differentially expressed genes (DEGs) in total lung cancers or each subgroup, and then searched for the similarities and differences among these. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed, in addition to predictable cell proliferation or immune-related pathways, 'hemostasis', 'coagulation' and 'viral myocarditis' were also enriched in common DEGs, while specific functions or pathways were enriched in different subgroups. This may have implications for the treatment of total lung cancer or different subtypes. Through bioinformatics analysis, hub genes were obtained from total lung cancer and each subgroup respectively. Survival analysis of common hub genes led us to find that ZWINT, A2M, POLR2H and KIF11 are associated with unclassified lung cancer survival. For the construction of miRNA regulatory network, miR-16−5p was related to all of these four genes, and its expression is significantly different between lung cancers and normal samples. Combined with the hub genes of each subtype, it may have the ability of early screening and typing. [ABSTRACT FROM AUTHOR]

This Report presents a nitrogen-doping method by chemically forming self-assembled monolayers on silicon. Van der Pauw technique, secondary-ion mass spectroscopy and low temperature Hall effect measurements are employed to characterize the nitrogen dopants. The experimental data show that the diffusion coefficient of nitrogen dopants is 3.66 × 10−15 cm2 s−1, 2 orders magnitude lower than that of phosphorus dopants in silicon. It is found that less than 1% of nitrogen dopants exhibit electrical activity. The analysis of Hall effect data at low temperatures indicates that the donor energy level for nitrogen dopants is located at 189 meV below the conduction band, consistent with the literature value. [ABSTRACT FROM AUTHOR]