Evaluation and Optimization of Cement Slurry Systems for Ultra-Deep Well Cementing at 220 °C.

With the depletion of shallow oil and gas resources, wells are being drilled to deeper and deeper depths to find new hydrocarbon reserves. This study presents the selection and optimization process of the cement slurries to be used for the deepest well ever drilled in China, with a planned vertical depth of 11,100 m. The bottomhole circulating and static temperatures of the well were estimated to be 210 °C and 220 °C, respectively, while the bottomhole pressure was estimated to be 130 MPa.

Structural impacts on the degradation behaviors of Ir-based electrocatalysts during water oxidation in acid.

Large-scale hydrogen production by electrocatalytic water splitting still remains as a critical challenge due to the severe catalyst degradation during the oxygen evolution reaction (OER) in acidic media. In this study, we investigate the structural impacts on catalyst degradation behaviors using three iridium-based oxides, namely SrIrO, SrIrO, and SrIrO as model catalysts. These Ir oxides possess different connection configurations of [IrO] octahedra units in their structure.

Bivalirudin versus Heparin on Net Adverse Clinical Events, Major Adverse Cardiac and Cerebral Events, and Bleeding in Elderly Chinese Patients Treated with Percutaneous Coronary Intervention.

Bivalirudin as an anticoagulant reduces bleeding after percutaneous coronary intervention (PCI), while its impact in elderly Chinese patients treated with PCI needs more evidence. This study aimed to compare the clinical outcomes between bivalirudin and heparin in elderly Chinese patients treated with PCI. This cohort study retrieved data of 1,286 elderly patients treated with PCI who used bivalirudin (bivalirudin group, N = 493) or heparin (heparin group, N = 793) as anticoagulants.

Electrochemical Preparation of Crystalline Hydrous Iridium Oxide and Its Use in Oxygen Evolution Catalysis.

Even the most stable Ir-based oxides inevitably encounter a severe degradation problem during the oxygen evolution reaction (OER) in acid, resulting in quick formation of amorphous IrO layers on the catalyst surface. Unfortunately, there is still a lack of fundamental understanding of such hydrous IrO layers, including the atomic arrangement, key active structure, compositions, chemical stability, and so on. In this work, we demonstrate an electrochemical strategy to prepare two types of protonated iridium oxides with well-defined crystalline structures: one possesses a 2D layered structure (denoted as α-HIrO) and the other consists of 3D interconnected polymorphs (denoted as β-HIrO).

Rational Design of Silicon Nanodots/Carbon Anodes by Partial Oxidization Strategy with High-Performance Lithium-Ion Storage.

Silicon (Si) is considered a promising anode material for rechargeable lithium-ion batteries (LIBs) due to its high theoretical capacity, low working potential, and safety features. However, the practical use of Si-based anodes is hampered by their huge volume expansion during the process of lithiation/delithiation, and they have relatively low intrinsic electronic conductivity, therefore seriously restricting their application in energy storage. Here, we propose a facile approach to directly transform siliceous biomass (bamboo leaves) into a porous carbon skeleton-wrapped Si nanodot architecture through a partial oxidization strategy and magnesium thermal reaction to obtain a high Si nanodot component composite (denoted as Si/C-O).

Investigation on a high gravity device for reduction of NOx emission from marine diesel engines.

High gravity technology, as a process intensification technology, has demonstrated the great advantages in the field of gas purification on account of its excellent mass transfer efficiency and energy-efficient, but it is rarely applied in the field of nitrogen oxides (NOx) purification of marine diesel engine exhaust. In this paper, a high-gravity bowl-shaped-disk rotating bed (HBRB) without catalytic was designed for diesel exhaust after-treatment. A diesel oxidation catalyst (DOC) was installed in the front of the HBRB to regenerate more nitrogen dioxide (NO) easily reduced by urea.

Investigation of the electrocatalytic mechanisms of urea oxidation reaction on the surface of transition metal oxides.

Urea oxidation reaction (UOR) has been widely considered as an alternative anodic reaction to water oxidation for the green production of hydrogen fuel. Due to the high catalytic activity of transition metal oxides towards UOR, various strategies have been developed to improve their syntheses and catalytic properties. However, little is known about the underlying mechanisms of UOR on catalyst surface.

Unveiling the promotion of intermediates transport kinetics on the N/S co-doping 3D structure titanium carbide aerogel for high-performance supercapacitors.

Two-dimensional (2D) transition metal carbides (MXene) have shown great advantages as electrode materials in the new generation of energy storage, especially in supercapacitors. However, the inherent low specific capacitance and restacking layers of nanosheets that occur during electrode preparation further reduce the electrochemical performance of the materials. Based on this, we design a N, S co-doping electrode with a three-dimensional (3D) structure, which not only improves the specific capacitance through fundamentally modifying the electronic structure of the electrode materials, but also effectively improves the rate performance of the electrode by preventing the restacking of 2D materials.

Theoretical prediction of HfB monolayer, a two-dimensional Dirac cone material with remarkable Fermi velocity.

Searching for new two-dimensional (2D) Dirac cone materials has been popular since the discovery of graphene with a Dirac cone structure. Based on density functional theory (DFT) calculations, we theoretically designed a HfB monolayer as a new 2D Dirac material by introducing the transition metal Hf into a graphene-like boron framework. This newly predicted HfB monolayer has pronounced thermal and kinetic stabilities along with a Dirac cone with a massless Dirac fermion and Fermi velocities (3.

Functional Group Effects on the Photoelectronic Properties of MXene (ScCT, T = O, F, OH) and Their Possible Photocatalytic Activities.

In view of the diverse functional groups left on the MXene during the etching process, we computationally investigated the effects of surface-group types on the structural, electronic and optical properties of ScCT (T = -O, -OH, -F) MXenes. For all geometries of the ScCT MXenes, the geometry I of ScCT, which has the functional groups locating above the opposite-side Sc atoms, are lowest-energy structure. Accordingly, the energetically favorable ScCF-I, ScCO-I and ScC(OH)-I were selected for further evaluation of the photocatalytic activities.