Video Experimental Relacionado

Updated: Sep 9, 2025

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Published on: May 15, 2015

Progresos recientes de las tierras raras basadas en intermetálicos y aleaciones para la licuefacción de hidrógeno

Zhipan Ma¹, Lingwei Li²

¹Department of Basic, Rocket Force University of Engineering, Xi'an, Xi'an, 710025, CHINA.

Journal of physics. Condensed matter : an Institute of Physics journal

|September 2, 2025

Resumen

Los investigadores revisaron materiales magnetocalóricos basados en tierras raras para un enfriamiento eficiente. Los avances en la ciencia de los materiales son cruciales para el desarrollo de la refrigeración magnética para la licuefacción de hidrógeno.

Área de la Ciencia:

Ciencias de los materiales
La termodinámica
Ingeniería Química

Sus antecedentes:

La refrigeración magnética ofrece un enfriamiento de alta eficiencia a través del efecto magnetocalórico (MCE).
Las aplicaciones a gran escala están limitadas por la falta de materiales magnetocalóricos óptimos.
Los materiales basados en tierras raras son candidatos clave para las aplicaciones de MCE.

Objetivo del estudio:

Para revisar los avances recientes en materiales magnetocalóricos basados en tierras raras.
Centrarse en los materiales adecuados para las temperaturas de licuefacción del hidrógeno.
Para resumir las propiedades magnéticas y magnetocalóricas y el origen de MCE.

Principales métodos:

Revisión de la literatura sobre las investigaciones de los últimos cinco años.
Análisis de las propiedades magnéticas y magnetocalóricas.
Resumen de las modificaciones estructurales y de composición.

Principales resultados:

Se presentan desarrollos recientes en materiales magnetocalóricos basados en tierras raras.
Se mejora la comprensión del origen del MCE en estos materiales.
Las modificaciones estructurales y de composición muestran potencial para propiedades de afinación.

Conclusiones:

Se necesita una mayor exploración para comprender las razones subyacentes de la mejora del rendimiento.
Los materiales magnetocalóricos optimizados son esenciales para el avance de la tecnología de refrigeración magnética.
El enfoque en materiales de tierras raras podría desbloquear el enfriamiento eficiente de la licuefacción de hidrógeno.

Palabras clave:

aleaciones el hidrógeno Productos intermetálicos Licuefacción tierras raras

Más Videos Relacionados

In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure

In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure

Published on: March 31, 2018

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions

Published on: August 17, 2016

Videos de Conceptos Relacionados

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...

Reduction of Alkenes: Catalytic Hydrogenation

Reduction of Alkenes: Catalytic Hydrogenation

Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...

Acid Halides to Alcohols: LiAlH4 Reduction

Acid Halides to Alcohols: LiAlH₄ Reduction

Acid halides are reduced to alcohols in the presence of a strong reducing agent like lithium aluminum hydride.
The mechanism proceeds in three steps. First, the nucleophilic hydride ion attacks the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs as a leaving group, generating an aldehyde. A second nucleophilic attack by the hydride yields an alkoxide ion, which, upon protonation, gives a primary alcohol as...

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.

Alcohols from Carbonyl Compounds: Reduction

Alcohols from Carbonyl Compounds: Reduction

Reduction is a simple strategy to convert a carbonyl group to a hydroxyl group. The three major pathways to reduce carbonyls to alcohols are catalytic hydrogenation, hydride reduction, and borane reduction.
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat (25–100°C) and...

Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride

Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride

Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...