1,723,369 research outputs found
Spatial pattern and fairness measurement of educational resources of primary and middle schools in Western China: A case study of Chengdu-Chongqing urban agglomeration
No full textThe data includes the number of teachers, schools and students in Chengdu Chongqing urban agglomeration from 2010 to 2019
Home education of a bright student%253A a case analysis on Lu Wei
No full textIn this article, the authors explore the life history and home education of Lu Wei, a top student in the 2004 Guangdong Province College entrance examination. The authors argue that the following issues of Lus home education played an important role in Lus success%253A emphasis and nurture of intellectual development in the early years of life, mutual support, respect and care among family members. The authors state that parents personal involvement and examples have played a crucial role in Lus success
An Integrated Fuzzy Simulation-Optimization Model for Supporting Low Impact Development Design under Uncertainty
No full text10.1007/s11269-019-02377-7Water Resources Management33124351-436
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Electronic and Bonding Properties of LiMn₂O₄ Spinel with Different Surface Orientations and Doping Elements and their Effects on Manganese Dissolution
No full textThis paper investigates the effects of surface orientation and doping on the dissolution of Mn ions from LiMn2O4 structures using first principles calculations. Our aim is to understand why certain surface orientations and element dopings produce structures with lower Mn dissolution. By comparing the electronic properties and structures of systems with different surfaces and dopings, Mn dissolution mechanisms and their prevention can be better understood. Based on our calculations, Mn dissolution is strongly correlated with the electronic and bonding properties of the Mn-O bonds. Surface orientations with a larger number of Mn-O bonds and smaller bond length require more energy to break the Mn-O bonds. In addition, doping with certain elements changes the bonding state of Mn, which either prevents or aggravates Mn dissolution
A Comprehensive Experimental and Modeling Study on Dissolution in Li-Ion Batteries
Full text linkDissolution is a critical challenge in metal oxide battery materials, which affects battery performance across multiple scales. At the particle level, the loss of active material as a result of dissolution directly results in capacity fade. At the electrode level, the re-deposition of dissolved metal ions onto the cathode increases cell polarization and hinders lithium transport. At the cell level, the dissolved ions further transport to and deposit on the anode, which consumes cycle-able lithium and leads to capacity fade. These processes lead to poor lithium reversibility, diffusivity, and conductivity. In this work, detailed experimental studies from the particle level up to the cell level are systematically conducted to provide parameters for model input and model validation. A multi-physics modeling framework is developed to reveal key mechanisms associated with metal-ion dissolution and their impact on battery performance. We simulate capacity degradation during cycling and compare the results to a series of experimental data such as cyclic voltammetry, electrochemical impedance spectroscopy, and battery cycling. The integrated study have revealed several key mechanisms related to dissolution, and quantitatively connected the particle level dissolution and deposition behaviors to the cell level performance. These can provide useful guidance for battery design and management
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