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1.
Artículo en Inglés | MEDLINE | ID: mdl-36982113

RESUMEN

Studies on policy change focus on governmental decision-making from a technical rationality perspective, ignoring the fact that policy change is a complicated social construction process involving multiple actors. This study used the modified advocacy coalition framework to explain changes in China's family planning policy and discourse network analysis to show the debate on the birth control policy among multiple actors (central government, local governments, experts, media, and the public). It found that the dominant coalition and the minority coalition can learn and adjust deep core beliefs from each other; the sharing and flow of actors' policy beliefs drive change in the network structure; and actors' obvious preferential attachment when the promulgation of the central document, are all helpful in policy change. This study can explain macro-policy changes from a micro-perspective to reveal the process and mechanism of policy changes in China's authoritarian regime.


Asunto(s)
Política de Planificación Familiar , Servicios de Planificación Familiar , Humanos , Gobierno , China
2.
Chemosphere ; 313: 137330, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36410510

RESUMEN

With the vigorous development of industrial economy, energy and environmental problems have become the most serious issues affecting people's production and life. Therefore, the demand for clean energy production, effective separation and storage is growing. Metal-organic frameworks (MOFs), as a kind of porous crystalline materials with large surface area and porosity, which is self-assembled by metal ions or clusters and organic ligands through coordination bonds. Thanks to a number of unique characteristics such as adjustable pore environment, homogeneous void structure, abundant active sites, unprecedented chemical composition tunability and functional versatility, it has been widely studied, especially for the clean energy conversion in catalysis. In this review, we focus on the research progress of clean energy in catalysis based on MOFs. Emphasis is placed on MOFs with different structures of compositions and their applications in catalytic for clean energy conversion, such as CO oxidation, CO2 reduction and H2 evolution. In addition, the situation of MOFs assisting environmental remediation is also briefly described. Finally, the prospects and challenges of MOFs in clean energy and the remaining issues in this field are presented.


Asunto(s)
Estructuras Metalorgánicas , Humanos , Estructuras Metalorgánicas/química , Metales/química , Catálisis , Porosidad , Oxidación-Reducción
3.
Chemosphere ; 313: 137324, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36410520

RESUMEN

Negative impacts of wastewater contamination include harm to the environment, people, plants, and animals. Metal-based heterogeneous catalysts, particularly transition metal oxide catalysts, are a therapeutic option. However, they have limited reusability and cause secondary contaminations through metal leaching. In this work, a new membrane catalyst made of perovskite-type fiber was created and tested to remove methylene blue from wastewater. These innovative 3D perovskite ceramic catalysts work well in the breakdown of pollutants and dramatically lessen possible secondary contaminations caused by metal leaching from catalysts.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Óxidos , Oxidación-Reducción , Titanio , Catálisis , Contaminantes Químicos del Agua/análisis
4.
Chemosphere ; 308(Pt 2): 136272, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36067809

RESUMEN

Tonnage oxygen production is still mostly based on the traditional technology of cryogenic distillation, a century-old, capital- and energy-intensive method. It is critical to create a novel low-cost, energy-efficient approach that can meet the growing demand for oxygen in industry from the clean environmental or energy standpoint. Ruddlesden-Popper (RP) perovskite like oxides -based ionic transport membranes for the oxygen transport have recently been developed as a possible replacement for the traditional cryogenic approach. In this work, we detailly reviewed the progress of RP perovskite oxides based membranes for oxygen transport from separation mechanism, material types, synthesis methods to the final separation performance. This work advances the development of RP perovskite membranes for oxygen transport.


Asunto(s)
Compuestos de Calcio , Oxígeno , Óxidos , Titanio
5.
Chemosphere ; 305: 135483, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35753420

RESUMEN

The mixed ionic-electronic conducting (MIEC) oxides have generated significant research efforts in the scientific community during the last 40 years. Since then, many MIEC compounds, most of which are based on perovskite oxides, have been synthesized and characterized. These compounds, when heated to high temperatures, form solid ceramic membranes with high oxygen ionic and electrical conductivity. The driving force for oxygen ion transport is the ionic transfer of oxygen from the air as a result of the differential partial pressure of oxygen across the membrane. Electronic and ionic transport in a range of MIEC materials has been studied using the defect theory, particularly when dopants are introduced to the compound of interest. As a result, many types of ionic oxygen transport limits exist, each with a distinct phase shift depending on the temperature and partial pressure of oxygen in use. In combination with theoretical principles, this work attempts to evaluate the research community's major and meaningful achievements in this subject throughout the preceding four decades.

6.
Materials (Basel) ; 12(16)2019 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-31405101

RESUMEN

In this study, radial crystallization purification method under induction was proposed for preparing 6N,7N ultra-high purity gallium crystal seed. The effect of cooling temperature on the morphology of the crystal seed, as well as the cooling water temperature, flow rate, and the addition amount of crystal seed on the crystallization process was explored, and the best purification process parameters were obtained as follows: temperature of the crystal seed preparation, 278 K; temperature and flow rate of the cooling water, 293 K and 40 L·h-1, respectively; and number of added crystal seed, six. The effects of temperature and flow rate of the cooling water on the crystallization rate were investigated. The crystallization rate decreased linearly with increasing cooling water temperature, but increased exponentially with increasing cooling water flow. The governing equation of the crystallization rate was experimentally determined, and three purification schemes were proposed. When 4N crude gallium was purified by Scheme I, 6N high-purity gallium was obtained, and 7N high-purity gallium was obtained by Schemes II and III. The purity of high-purity gallium prepared by the three Schemes I, II, and III was 99.999987%, 99.9999958%, and 99.9999958%, respectively.

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