Lithiophilic Carbon Nanofiber/Graphene Nanosheet Composite Scaffold Prepared by a Scalable and Controllable Biofabrication Method for Ultrastable Dendrite-Free Lithium-Metal Anodes.

Li metal is regarded as a promising anode for high-energy-density Li batteries, while the limited cycle life and fast capacity decay caused by notorious Li dendrite growth seriously impedes its application. Herein, a robust and highly lithiophilic bacterial cellulose-derived carbon nanofiber@reduced graphene oxide nanosheet (BC-CNF@rGO) composite scaffold is fabricated as a host for dendrite-free Li metal anode through an in situ biofabrication method. The abundant lithiophilic functional groups, conductive 3D network, and excellent mechanical property can effectively regulate uniform Li nucleation and deposition, enable fast reaction kinetics, and alleviate volume change. As a result, the BC-CNF@rGO skeleton achieves exceptional Li plating/stripping performance with a high average Coulombic efficiency of 98.3% over 800 cycles, and a long cycle life span of 5000 h at 2 mA cm-2 @1 mAh cm-2 with a low overpotential of ≈15 mV for lithium plating. Furthermore, full cells coupling BC-CNF@rGO-Li anode with LiFePO4 cathode achieves an unprecedented cycling stability with a long cycle life of 3000 cycles at 1 C. This work sheds light on a promising material design and fabrication strategy for realizing high performance Li metal batteries.

Highly Potassiophilic Carbon Nanofiber Paper Derived from Bacterial Cellulose Enables Ultra-Stable Dendrite-Free Potassium Metal Anodes.

Potassium-metal batteries are attractive candidates for low-cost and large-scale energy storage systems due to the abundance of potassium. However, K metal dendrite growth as well as volume expansion of K metal anodes on cycling have significantly hindered its practical applications. Although enhanced performance has been reported using carbon hosts with complicated structure engineering, they are not suitable for mass production. Herein, a highly potassiophilic carbon nanofiber paper with abundant oxygen-containing functional groups on the surface and a 3D interconnected network architecture is fabricated through a facile, scalable, and environmental-friendly biosynthesis method. As a host for K metal anode, uniform K nucleation and stable plating/stripping performance are demonstrated, with a stable cycling of 1400 h and a low overpotential of 45 mV, which are much better than all carbon hosts without complicated structure engineering. Moreover, full cells pairing the carbon nanofiber paper/K composite anodes with K4Fe(CN)6 cathodes exhibit excellent cycle stability and rate capability. The results provide a promising way for realizing dendrite-free K metal anodes and high-performance potassium-ion batteries.

Analysis of Factors Related to Cerebral Infarction after Direct Bypass Surgery in Adults with Moyamoya Disease.

OBJECTIVE: High-risk factors of the patients with moyamoya disease (MMD) were analyzed to provide the basis for prediction and management of cerebral infarction after direct bypass surgery in adult MMD. METHODS: 1. Retrospective analysis of clinical data was collected from adult MMD patients (n = 250) following superficial temporal artery-middle cerebral artery bypass surgery performed in our hospital from July 2013 to December 2017. Of the 250 patients, all underwent hemispherical bypass surgery, and bilateral surgery was performed on 14 patients. 2. Clinical data were analyzed based on sex, age, hypertension, diabetes, smoking history, history of alcohol use, presurgery cerebral infarction, transient ischemic attack, classification of clinical manifestations, clinical typing, Suzuki stage of surgical side, Suzuki stage of nonoperative side, preoperative Modified Rankin Scale (MRS), and lesions of the postoperative cycle or not. RESULTS: 1. There were significant differences in classification of clinical manifestations, preoperative infarction, clinical typing, and Suzuki stage of nonoperative side (p < 0.05). 2. Logistic regression analysis showed that the independent factors affecting postoperative cerebral infarction were preoperative infarction and the Suzuki stage of nonoperative side (p < 0.05). The preoperative infarction (B 1.431, OR 4.184, 95% CI 1.217-14.382) and the Suzuki stage of nonoperative side (B 0.495, OR 1.640, 95% CI 1.207-2.227) were both risk factors. CONCLUSION: The possibility of a new cerebral infarction in postoperative patients with a history of cerebral infarction was greater. The Suzuki stages (I-VI) of the nonoperative side was higher and associated with an increased probability of cerebral infarction after surgery.

On theory and methods for advanced detonation-driven hypervelocity shock tunnels.

This study describes theory and methods for developing detonation-driven shock tunnels in hypervelocity test facilities. The primary concept and equations for high-enthalpy shock tunnels are presented first to demonstrate the unique advantage of shock tubes for aerodynamic ground-based testing. Then, the difficulties in simulating flight conditions in hypervelocity shock tunnels are identified, and discussed in detail to address critical issues underlying these difficulties. Theory and methods for developing detonation drivers are proposed, and relevant progress that has advanced the state of the art in large-scale hypersonic test facilities is presented with experimental verifications. Finally, tailored conditions for detonation-driven shock tunnels are described, laying a solid foundation to achieve long test duration. This interface-matching key issue encountered in developing shock tunnels has been investigated for decades, but not solved for detonation drivers in engineering applications.

Catalytic reactions of chlorite with a polypyridylruthenium(II) complex: disproportionation, chlorine dioxide formation and alcohol oxidation.

cis-[Ru(2,9-Me(2)phen)(2)(OH(2))(2)](2+) reacts readily with chlorite at room temperature at pH 4.9 and 6.8. The ruthenium(II) complex can catalyze the disproportionation of chlorite to chlorate and chloride, the oxidation of chlorite to chlorine dioxide, as well as the oxidation of alcohols by chlorite.

Lewis acid-activated oxidation of alcohols by permanganate.

The oxidation of alcohols by KMnO(4) is greatly accelerated by various Lewis acids. Notably the rate is increased by 4 orders of magnitude in the presence of Ca(2+). The mechanisms of the oxidation of CH(3)OH and PhCH(OH)CH(3) by MnO(4)(-) and BF(3)·MnO(4)(-) have also been studied computationally by the DFT method.