Phase Control on Surface for the Stabilization of High Energy Cathode Materials of Lithium Ion Batteries.

The development of high energy electrode materials for lithium ion batteries is challenged by their inherent instabilities, which become more aggravated as the energy densities continue to climb, accordingly causing increasing concerns on battery safety and reliability. Here, taking the high voltage cathode of LiNi0.5Mn1.5O4 as an example, we demonstrate a protocol to stabilize this cathode through a systematic phase modulating on its particle surface. We are able to transfer the spinel surface into a 30 nm shell composed of two functional phases including a rock-salt one and a layered one. The former is electrochemically inert for surface stabilization while the latter is designated to provide necessary electrochemical activity. The precise synthesis control enables us to tune the ratio of these two phases, and achieve an optimized balance between improved stability against structural degradation without sacrificing its capacity. This study highlights the critical importance of well-tailored surface phase property for the cathode stabilization of high energy lithium ion batteries

Pringle manoeuvre versus selective hepatic vascular exclusion in partial hepatectomy for tumours adjacent to the hepatocaval junction: A randomized comparative study

AbstractObjectiveTo compare the efficacy of selective hepatic vascular exclusion versus Pringle manoeuvre in partial hepatectomy for tumours adjacent to the hepatocaval junction.MethodsA randomized comparative trial was carried out. The primary endpoint was intraoperative blood loss. The secondary endpoints were operation time, blood transfusion, postoperative liver function recovery, procedure-related morbidity and in-hospital mortality.Results160 patients were randomized into 2 groups: the Pringle manoeuvre group (n = 80) and the selective hepatic vascular exclusion (SHVE) group (n = 80). Intraoperative blood loss and transfusion requirements were significantly less in the SHVE group. In the SHVE group, laceration of hepatic veins happened in 18 patients. Profuse intraoperative blood loss of over 2 L happened in 2 patients but no patient suffered from air embolism because the hepatic veins were controlled. In the Pringle group, the hepatic veins were lacerated in 20 patients, with profuse blood loss of over 2 L in 7 patients and air embolism in 3 patients. The rates of postoperative bleeding, reoperation, liver failure and mortality were significantly higher and the ICU stay and hospital stay were significantly longer in the Pringle group.ConclusionsSHVE was more efficacious than Pringle manoeuvre for partial hepatectomy in patients with tumours adjacent to the hepatocaval junction

Pairing symmetry and properties of iron-based high temperature superconductors

Pairing symmetry is important to indentify the pairing mechanism. The analysis becomes particularly timely and important for the newly discovered iron-based multi-orbital superconductors. From group theory point of view we classified all pairing matrices (in the orbital space) that carry irreducible representations of the system. The quasiparticle gap falls into three categories: full, nodal and gapless. The nodal-gap states show conventional Volovik effect even for on-site pairing. The gapless states are odd in orbital space, have a negative superfluid density and are therefore unstable. In connection to experiments we proposed possible pairing states and implications for the pairing mechanism.Comment: 4 pages, 1 table, 2 figures, polished versio