Li[Li0.2Ni0.2Mn0.6]O2, which is a cathode material for Li-ion batteries with enhanced capacity, has been examined, for the first time, with a combination of aberration-corrected scanning transmission electron microscopy (STEM), STEM computer simulations, and diffraction scanning transmission electron microscopy (D-STEM). These techniques, in combination with X-ray diffraction (XRD) and conventional electron diffraction (ED), indicate that this material is composed of a solid solution with C2/m monoclinic symmetry and multiple planar defects. In addition, we show that XRD and ED alone can give misleading information and cannot resolve the structure of these materials without the additional use of the aforementioned techniques.

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The two-dimensional polyhedral anion network melilites La 1þx Sr 1-x Ga 3 O 7þ0.5x exhibit interstitial oxide ion conductivity. The solid solution is shown to extend to x = 0.64, and the variation of the conductivity with x is investigated. At high temperatures, all of these compounds adopt the typical tetragonal melilite structure. When x > 0.6, cooling below 600 °C results in a reversible phase transition to an orthorhombic structure which reduces the ionic conductivity. Quenching experiments have shown the tetragonal structure has a higher conductivity compared to the orthorhombic structure of the same composition. Short-range order effects associated with this transition exercise an important influence on the composition-and temperature-dependence of the conductivity.

Planar defects in lithium-rich layered oxides were examined by aberration-corrected scanning transmission electron microscopy (STEM) to understand their formation. Planar defects were found to form during the transition of the transition metal layer from a disordered R 3m state to a lithiumordered C2/m state. This disorder-to-order transition resulted in three orientation variants, namely [100], [110], and [1 10]. The fundamental mechanism behind the observed defects is a shear of AEb/3[010] on the (001) transition metal planes, which is equivalent to the point group operations lost during the disorder-to-order transition. These displacements also produced twins and single unit cells with P3 1 12 symmetry. Lithium-rich layered oxides with and without nickel show the presence of these three orientation variants.

This paper reports the evaluation of the cubic B site cation-ordered double perovskite system Ba2Co2−x (Mo1/2Nb1/2) x O6, resulting in the single phase composition Ba2CoMo0.5Nb0.5O6−δ (BCMN) with a mixed Co charge state stabilized by a combination of Mo and Nb doping as a new mixed conductor with potential SOFC cathode applications. X-ray, neutron, and electron diffraction show that hexagonal intergrowths found in multiple phase samples at lower Mo/Nb contents are suppressed in BCMN, which has large domains of rock-salt ordered B site cations with separate Co and Mo/Nb sites. Conductivity measurement and impedance spectroscopy investigation shows that BCMN has a considerably reduced dc conductivity compared with materials such as BSCF but exhibits comparable electrochemical properties to some existing cathode materials in symmetrical cell measurements, and shows higher structural stability and reduced reactivity with the Ce0.8Sm0.2O2−δ (SDC) electrolyte. The role of Mo in dioxygen activation is proposed to offset the reduction that the d 0 Mo(VI) and Nb(V) cations on the B site produce in the electronic and ionic conductivity.

ObjectiveCases with coronavirus disease 2019 (COVID-19) emigrated from Wuhan escalated the risk of spreading in other cities. This report focused on the outside-Wuhan patients to assess the transmission and clinical characteristics of this illness. MethodsContact investigation was conducted on each patient who admitted to the assigned hospitals in Hunan Province (geographically adjacent to Wuhan) from Jan 22, 2020 to Feb 23, 2020. Patients were confirmed by PCR test. Demographic, clinical and outcomes were collected and analyzed. ResultsOf the 104 patients, 48 (46.15%) were imported cases who were immigrated from Wuhan; 93 (89.42%) had a definite contact history with infections. Family clusters were the major body of patients. Transmission along the chain of 3 "generations" was This article is protected by copyright. All rights reserved. Accepted Articleobserved. Five asymptomatic infections were found and 2 of them infected their relatives.Mean age was 43 (rang, 8-84) years and 49 (47.12%) were male. The median incubation period was 6 (rang, 1-32) days, of 8 patients ranged from 18 to 32 days, 96 (92.31%) discharged and 1 (0.96%) died. Average hospital stay was 10 (rang, 8-14) days. ConclusionsFamily but not community transmission occupied the main body of infections in the two centers, suggesting the timely control measures after the Wuhan shutdown wok well.Asymptomatic transmission demonstrated here warned us that it may bring more risk to the spread of COVID-19. A 14-day quarantine may need to be prolonged.

This paper explores the relationship between urbanization rate and death incidence by applying panel threshold regression model to the inland provinces of China. The empirical results highlight that there is a nonlinear single threshold effect between urbanization and population health indicators. In China's inland provinces, the negative impact of urbanization on death rate is reduced when per capita GDP exceeds the threshold, that is, the positive impact of urbanization on population health is significantly weakened. Similarly, this result can also be applied to the north provinces, while there is a no threshold effect in south. These asymmetric effects are strongly related to geographical location, historical background, economic development conditions, and health policies. Therefore, in the urbanization process, while promoting the steady development of population urbanization, the government should also increase health investment to improve the system and mechanism, formulate policies to raise health awareness, protect residents' health and reduce the waste of health resources.

Complex transition-metal oxides are important functional materials in areas such as energy and information storage. The cubic ABO3 perovskite is an archetypal example of this class, formed by the occupation of small octahedral B-sites within an AO3 network defined by larger A cations. We show that introduction of chemically mismatched octahedral cations into a cubic perovskite oxide parent phase modifies structure and composition beyond the unit cell length scale on the B sublattice alone. This affords an endotaxial nanocomposite of two cubic perovskite phases with distinct properties. These locally B-site cation-ordered and -disordered phases share a single AO3 network and have enhanced stability against the formation of a competing hexagonal structure over the single-phase parent. Synergic integration of the distinct properties of these phases by the coherent interfaces of the composite produces solid oxide fuel cell cathode performance superior to that expected from the component phases in isolation.