Effects of NO in oxidant and initial temperature on working characteristics of MON-X/MMH liquid space thruster.

With the progress of deep space exploration activities, low freezing point propellants are required to ensure the normal operation of aerospace engines in deep space environments. Blending NO and nitrogen tetroxide is a commonly used method to decrease freezing point of propellant, which is called MON-X. Researches on MON-X/methyl hydrazine thruster with impinging injection and influences of initial temperature are rare, and there hasn't been a comparison between nitrogen tetroxide/methyl hydrazine thrusters and MON-X/methyl hydrazine thrusters.

Construction of "organic-inorganic" hybrid structures via metal polyphenol networks: Mussel-inspired simple, green and efficient strategy to improve interfacial adhesion of composites.

Traditional modifications of carbon fibers often suffer from high energy consumption, extensive use of chemical reagents, and potential damage to the intrinsic structure of the fibers. To address these issues, a mussel-inspired simple, green and efficient strategy was proposed. This strategy leverages π-π stacking and hydrogen bonding to facilitate the layer-by-layer self-assembly of metal polyphenol networks (MPN)‑carbon nanotubes (CNT) "organic-inorganic" hybrid structures onto the surface of carbon fibers.

ReaxFF-Based Molecular Dynamics Study of the Mechanism of the Reaction of NO with HO.

During long-term storage of the liquid propellant NO, it absorbs HO to form the NO(HO) system, and this in turn generates HNO, HNO, and other substances in the storage tank because of corrosion, which seriously affects the performance of weaponry. In this work, we carried out computational simulations of NO with different masses of water based on ReaxFF, analyzed the reaction intermediates and products, and investigated the mechanism of the reaction of NO with HO and of NO(HO). The results show that the reaction product ω(HNO+HNO) undergoes a rapid growth in the early stage of the reaction and then tends toward dynamic equilibrium; the potential energy of the system decreases with the increase of ω(HO), the reaction rate increases, and the rate of decomposition of HNO to form HNO increases.

Adsorption and desorption behavior of Zn in a flow-through electrosorption reactor.

As heavy metal industrial wastewater increases in volume and complexity, we need more efficient, cheaper, and renewable technologies to curb its environmental impact. Compared to advection electrosorption, through-flow electrosorption is a hotspot technique that makes more efficient use of the adsorption capacity of activated carbon fiber mats. A cascade flow-through electrosorption assembly based on activated carbon fiber was used to obtain the best adsorption of Zn in water at a voltage of 2 V, pH value of 8, plate spacing of 3 mm, and temperature of 15°C.

Interfacial π-p Electron Coupling Prompts Hydrogen Evolution Reaction Activity in Acidic Electrolyte.

The thermodynamically stable 2H-phase MoS is a brilliant material toward hydrogen evolution reaction (HER) owing to its excellent Gibbs free energy of hydrogen adsorption. Nevertheless, the poor intrinsic properties of 2H-MoS limit its electrocatalytic performances toward HER. In this work, graphitic carbon nitride covalently bridging 2H-MoS (MoS/GCN) is proposed to construct robust HER electrocatalysts.

Engineering Molecular Heterostructured Catalyst for Oxygen Reduction Reaction.

Introducing a second metal species into atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts to construct diatomic sites (DASs) is an effective strategy to elevate their activities and stabilities. However, the common pyrolysis-based method usually leads to substantial uncertainty for the formation of DASs, and the precise identification of the resulting DASs is also rather difficult. In this regard, we developed a two-step specific-adsorption strategy (pyrolysis-free) and constructed a DAS catalyst featuring FeCo "molecular heterostructures" (FeCo-MHs).

Self-Consistent Implementation of a Solvation Free Energy Framework to Predict the Salt Solubilities of Six Alkali Halides.

To assess the salt solubilities of six alkali halides in aqueous systems, we proposed a thermodynamic cycle and an efficient molecular modeling methodology. The Gibbs free energy changes for vaporization, dissociation, and dissolution were calculated using the experimental data of ionic thermodynamic properties obtained from the NBS tables. Additionally, the Marcus' and Tissandier's solvation free energy data for Li, Na, K, Cl, and Br ions were compared with the conventional solvation free energies by substituting into our self-consistent thermodynamic cycle.

New technology for preparing energetic materials by nanofiltration membrane (NF): rapid and efficient preparation of high-purity ammonium dinitramide (ADN).

The development of environment-friendly and non-toxic green energetic materials and their safe, environmentally friendly, and economical production is very important to the national economy and national security. As an innovative, efficient, and environmentally friendly energetic material, the preferred preparation method of ammonium dinitramide (ADN) is the nitro-sulfur mixed acid method, which has the advantages of high yield, simple method, and easy access to raw materials. However, the large number of inorganic salt ions introduced by this method limits the large-scale production of ADN.

En Route to High-Density Chiral Single-walled Carbon Nanotube Arrays using Solid Trojan Catalysts.

Solid catalyst is widely recognized as an effective strategy to control the chirality of single-walled carbon nanotubes (SWNTs). However, it is still not compatible with high density in horizontal arrays. "Trojan" catalysts strategy is one of the most effective methods to realize SWNTs with high density and has great potential in chirality control.

The Contributions of Supramolecular Kinetics to Dynamics of Supramolecular Polymers.

Supramolecular polymers exhibit well-controlled dynamics with fascinating capacity for remodeling, self-healing, and stimuli-responsiveness. Supramolecular kinetics of non-covalent bonds is a dominant control handle among the relevant factors to tailor dynamics of supramolecular polymers. This Review focuses on elucidating how supramolecular kinetics dictates the polymer dynamics in supramolecular polymer systems.

Preparation of thioamides from alkyl bromides, nitriles, and hydrogen sulfide through a thio-Ritter-type reaction.

A novel thio-Ritter-type reaction of alkyl bromides, nitriles, and hydrogen sulfide has been explored, providing a straightforward approach toward functionally important thioamides. This transformation features a broad substrate scope, operational simplicity, use of available feedstock chemicals, and late-stage functionalizations of bioactive molecules. The reaction mechanism is also proposed.

Fast and efficient electrocatalytic oxidation of glucose triggered by CuO-CuO nanoparticles supported on carbon nanotubes.

Electrocatalytic glucose oxidation reaction (GOR) is the key to construct sophisticated devices for fast and accurately detecting trace glucose in blood and food. Herein, a noble-metal-free Cu/C-60 catalyst is fabricated by supporting CuO-CuO nanoparticles on carbon nanotubes through a novel discharge process. For GOR, Cu/C-60 shows a sensitivity as high as 532 μA mM cm, a detection limit as low as 1 μM and a steady-state response time of only 5.

Effect of the Addition of Graphene Nanoplatelets on the Thermal Conductivity of Rocket Kerosene: A Molecular Dynamics Study.

Rocket kerosene plays an important role in the regenerative cooling process of rocket thrust chambers. Its thermal conductivity determines the cooling efficiency and the tendency to coke in rocket kerosene engines. In this paper, graphene nanoplatelets (GNPs) were introduced into rocket kerosene to improve its thermal conductivity.

Effect of Polymer Drag Reducer on Rheological Properties of Rocket Kerosene Solutions.

Adding drag reduction agent (DRA) to rocket kerosene is an effective way to reduce the pipeline resistance of rocket kerosene transportation systems. However, so far, there have been few research reports on the effect of DRA on the rheological properties of rocket kerosene solution, especially from a microscopic perspective. In this study, coarse-grained molecular dynamics simulations were conducted to investigate the rheological properties of rocket kerosene solutions with DRAs of different chain lengths and concentrations.

Efficient Role of Nanosheet-Like PrO Induced Surface-Interface Synergistic Structures over Cu-Based Catalysts for Enhanced Methanol Production from CO Hydrogenation.

In a complex heterogeneous metal-catalyzed reaction process, unique cooperative effects between metal sites and surface-interface active sites, as well as favorable synergy between surface-interface active sites, can play crucial roles in improving their catalytic performances. In this work, a ZnO-modified Cu-based catalyst over defect-rich PrO nanosheets for high-efficiency CO hydrogenation to produce methanol was successfully constructed. It was demonstrated that an as-fabricated nanosheet-like Cu-based catalyst presented several structural advantages including the formation of highly dispersive Cu sites and the coexistence of abundant defective Pr-V-Pr structures (V: oxygen vacancy) and interfacial Cu-O-Pr sites.

Molecular Dynamics Study of Bubble Nucleation on an Ideally Smooth Substrate.

Questions regarding bubble nucleation on an ideally smooth surface are seemingly endless, but it can not be adequately verified yet because of the scale limitation (microscopic scale). Hence, in this study, bubble nucleation on an ideally smooth substrate is explored using the molecular dynamics simulation method. An ideally smooth hydrophilic platinum substrate at 145 K is conducted to heat the simple L-J liquid argon.

Transport Properties of Waxy Crude Oil: A Molecular Dynamics Simulation Study.

To study the effects of paraffin on viscosity of waxy crude oil and transport properties of small molecules, light and waxy crude oil models were investigated at atmospheric pressure and 293-323 K temperature range using atomistic molecular dynamics simulations. The optimized parameters for liquid simulations all-atom (OPLS-AA) and atomistic polarizable potential for liquids, electrolytes, and polymers (APPLE&P) force fields were employed. The self-diffusion coefficients, viscosity, and paraffin configurations were compared for two oil models and between the two employed force fields.

The self-assembly of an imidazolium surfactant in an aprotic ionic liquid. 1. Comparison in aprotic and protic ionic liquids.

The aggregation behaviour of a cationic surfactant in an aprotic ionic liquid has been explored. Prolate micelles are formed at low surfactant concentrations, while a lamellar lyotropic liquid crystal phase is formed at high surfactant concentrations.

Theoretical study on the gas-phase reaction mechanism of ammonia with nitrous oxide.

Applications of nitrous oxide (NO) as an oxidant in green propellants and propulsion systems have attracted a lot of attention. In this study, the reaction pathways for the oxidation of ammonia (NH) with NO were studied using the B3LYP/6-31++G** method of density functional theory (DFT). The results reveal that the reaction between NO and NH proceeds through a chain reaction mechanism.

A Photoactivated Cu-CeO Catalyst with Cu-[O]-Ce Active Species Designed through MOF Crystal Engineering.

Fully utilizing solar energy for catalysis requires the integration of conversion mechanisms and therefore delicate design of catalyst structures and active species. Herein, a MOF crystal engineering method was developed to controllably synthesize a copper-ceria catalyst with well-dispersed photoactive Cu-[O]-Ce species. Using the preferential oxidation of CO as a model reaction, the catalyst showed remarkably efficient and stable photoactivated catalysis, which found practical application in feed gas treatment for fuel cell gas supply.

The physical mechanism of magnetic field controlled magnetocaloric effect and magnetoresistance in bulk PrGa compound.

The PrGa compound shows excellent performance on the magnetocaloric effect (MCE) and magnetoresistance (MR). The physical mechanism of MCE and MR in PrGa compound was investigated and elaborated in detail on the basis of magnetic measurement, heat capacity measurement and neutron powder diffraction (NPD) experiment. New types of magnetic structure and magnetic transition are found.