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Magnetization dynamics and curie temperature study in SMCo5/Co core-shell nanostructures
No full textSmCo5/Co core-shell nanoparticles are studied for their ability to improve magnetic properties like coercivity and exchange-bias effects. The core-shell structure helps enhance these properties by allowing better control over the magnetic behaviour of the core, shell, and their interface. These nanoparticles can maintain strong magnetization, high coercivity, and improved energy efficiency. The structure allows for adjustable magnetic properties, giving insights into the core, shell, and their interactions effect on the overall magnetism. We use atomistic magnetic simulations with VAMPIRE software to study the magnetization reversal, coercivity, and Curie temperature in two different combination of exchange-coupled bi-magnetic hard/soft ferromagnetic core/shell nanoparticle. In the first configuration, SmCo5 is the hard magnetic core and Co is the soft magnetic shell. The core size (dc) varies from 0 to 4 nm, while the overall particle size stays around 5 nm. The results show that changing the shell thickness affects the microscopic interface pinning mechanism. Whether SmCo5 is the core with Co as the shell, or vice versa, the coercivity shows little change with variations in shell thickness, but it increases significantly compared to individual Co or SmCo5 nanoparticles. The findings confirm that the core-shell structure depends on the materials, core size, and temperature. We also investigate how the finite-size effect influences the Curie temperature of SmCo5 and Co nanoparticles using M-T graphs. The results show that the maximum energy product (BH)max strongly depends on core size. The SmCo5/Co core-shell nanoparticle combination boosts magnetic performance by utilizing SmCo5’s high magnetic strength for permanent magnets and the Co shell’s thermal stability for enhanced magnetization. This synergy makes them suitable for applications in permanent magnets, recording media, and biomedical uses.Accepted versio
Integrated biological and chemical investigation of Papuan marine organisms for the discovery of potential cytotoxic marine natural products
No full textAn integrated approach combining biological and chemical investigations were carried out to uncover novel cytotoxic molecules from diverse Papuan marine organisms. Of 386 marine-derived extracts, about 13% (50 extracts) showed significant toxicity in the Artemia salina lethality assay (LC50 ≤ 5 µg/mL). Analysis of the Z-factor and Z’-factor confirmed the excellent quality of the assay (Z = 0.76, Z’ = 0.5). Of the 50 active extracts, seven extracts from Achantostrongylophora ingens, Theonella sp., Ianthella basta, a cyanobacterium, a sponge from family Thorectidae, and a rare Axinella sp. were further evaluated for cytotoxicity against HEK293T, 1H NMR spectral, LC-HR-MS/MS, feature-based molecular networking (FBMN), and chemoinformatics analyses. The chemical analyses revealed the presence of 43 known and 381 putatively new bioactive molecules. The integrated biological and chemistry approach adopted in this study is effective for prioritising important marine extracts with high probability of discovering novel cytotoxic compounds
Johnstone’e non-sober dcpo and extensions
No full textThe open access publication is available at https://doi.org/10.3390/ijt2010003One classic result in domain theory is that the Scott space of every domain (continuous directed complete poset) is sober. Johnstone constructed the first directed complete poset (dcpo for short) whose Scott space is not sober. This non-sober dcpo has been used in many other parts of domain theory and more properties of it have been uncovered. In this survey paper, we first collect and prove the major properties (some of which are new as far as we know) of Johnstone’s dcpo. We then propose a general method of constructing a dcpo from given posets and prove some properties. Some problems are posed for further investigation. This paper can serve as a relatively complete resource on Johnstone’s dcpo
Understanding the order of numbers
No full textThis brief was based on the project OER 05/22 JDMM: Mechanisms Underlying Numeral Ordering Skills in Children
The diachronic evolution of the meaning of the word 'pianpian' and the path of its subjectivisation
No full text本文以“偏偏”一词为研究对象，系统考察其词义的历时演变及主观化路径。研究采用文献分析法、归纳法和因果分析法，结合CCL、BCC等语料库的历时语料，梳理“偏偏”从先秦至清代的语义发展脉络。研究发现，“偏偏”源于单音词“偏”，先秦时期“偏”的核心语义为“部分”与“偏离中心”，汉代逐渐语法化为副词，唐宋时期衍生出程度副词用法。明代“偏偏”作为双音节副词正式形成，承接“偏”的主观情态功能，主要表达“客观事实与主观愿望相悖”的意外态，并初步呈现交互主观性。至清代，“偏偏”广泛传播，语义进一步扩展，既保留范围副词用法，又强化了情态表达，其主观化路径体现为由道义情态转向评价情态、由行域进入知域的特征。研究还揭示，语言经济性原则与双音化趋势推动“偏偏”与“偏”的语义分工，前者侧重客观违愿，后者侧重主观违逆。通过结合Traugott的主观化理论和沈家煊的“知—行—言”三域理论，本文为汉语情态副词的历时演变提供了新的分析框架，深化了对主观性表达机制的理解
Microstructure and magnetic properties of CoCrCuFeNiTi high entropy alloy coatings based on plasma surface alloying technology
No full textThe present study explored the correlation between microstructure and magnetic properties of CoCrCuFeNiTi HEA coatings prepared on Si substrate using plasma surface alloying technology. The coatings exhibited a mixture of Fe2Ti, FeCr, FCC, BCC phase and the amorphous/crystalline structure. The mircrostructure changed with the deposition duration, resulting in different coercivity. The crystalline part of the coating deposited for 1.0 h contained up to 81.9 % of Fe2Ti and more amorphous structure, causing a coercivity of 53.1 Oe. Fe2Ti showed a preferred orientation along the (201) direction, leading to columnar structure in the coatings and the vertical growth of columnar structure caused an increase in coating thickness. As the deposition duration increased to 1.5 h, a reduction of Fe2Ti and amorphous structure, as well as an increase of defects such as grain boundaries allowed the coercivity to increase to 104.5 Oe. FCC, FeCr, and BCC phase increased as increase of deposition duration, and the relative content of BCC phase increased to a maximum of 8.3 % at a deposition duration of 2.0 h. An increase of grain size and nonuniform distribution of different phases in coating led to a reduction of coercivity to 82.9 Oe. However, the vertical growth of the columnar structure made the coating to exhibit obvious shape anisotropy and the coercivity increased to 118.3 Oe when deposition duration was 3.0 h. The coercivity of HEA coating prepared by plasma surface alloying technology were sensitive to microstructure, and the deposition duration needed to be controlled to obtain the desired coercivity.RI 7/22 RSRRP 6/22 RS
Cognitive and neural mechanisms of learning and interventions for improvement across the adult lifespan: A systematic review
No full textThere continues to be growing interest in the Science of Learning including identifying ways to apply findings. Presently, little is known about learning during healthy adulthood and methods to improve that learning. The main objective of the present systematic review is to identify and synthesize all recent cognitive and brain research investigating learning during healthy aging in adulthood. Searches were performed across Scopus, Web of Science, and ProQuest databases to identify published and unpublished studies conducted in healthy adults. Eligible studies reported measures of learning-related cognition, brain structure or function and their relationship with age, or effects of interventions to improve learning. Risk of bias was assessed using either the Mixed Methods Appraisal Tool or Critical Appraisal Skills Programme checklist. Search and screening were performed by three trained reviewers. Included studies were summarized using narrative synthesis and, for intervention studies, an effect direction plot. A total of 265 relevant studies were identified for inclusion. Studies were primarily lab-based cross-sectional studies conducted in Western contexts. Findings revealed an overall decline in learning-related cognitive and brain outcomes during healthy aging. However, declines were more pronounced in fluid abilities and explicit learning and memory while crystalized abilities and implicit learning and memory showed stability. Generally, higher education and socioeconomic status positively modulated age-related learning trajectories while baseline cognitive function influenced the effectiveness of interventions. Findings from the present systematic review are potentially limited by the exclusive focus on healthy aging and the small number of included studies conducted in non-Western contexts. Implications for policy, practice, and future research are discussed.Accepted versio
Systematicity in variability: English coda laterals of English-Malay bilinguals in multi-accent Singapore
No full textOutcomes of early phonological acquisition in multi-accent contexts can be especially wide-ranging, raising the question of whether children exposed to multiple accents in one community are building the same linguistic systems. This present study investigates the English coda clear laterals in the spontaneous, mother-directed speech of English-Malay early bilingual preschoolers raised in multi-accent Singapore. Previous work has shown that these children were exposed to highly variable input involving three different English coda /l/ variants within and outside of their ethnic community. To elucidate the complex nature of language acquisition in such diverse settings, we examine both individual differences and group behaviors. Our findings reveal that despite the considerable between- and within-child variation, production patterns are generally systematic. Malay children with close Chinese peers, however, exhibited greater variability and unpredictability in their production, revealing word-specific inconsistencies that suggest a restructuring of or instability in their phonological representations. This study underscores the complexity of phonological development in multi-accent contexts and highlights the challenges in predicting the contributors of these variable outcomes.Accepted versio
Transnational class anxieties and intensive parenting: Middle-class Chinese immigrant parents ‘doing security’ in Singapore
No full textThis paper explores middle-class Chinese immigrant parents' childrearing aspirations and strategies in Singapore. Drawing on in-depth interviews conducted with 31 professional middle-class immigrant parents from China in 2022, it examines how these parents intensify their childrearing as a strategy not only to cope with the structural insecurities they face in the host country but also to mitigate their perceived uncertainties evoked by the larger world beyond the host society. Through the conceptual lens of ‘doing security’, the paper unpacks the emotional dynamics and moral anxieties involved in the parents' efforts to maintain and improve their middle-class positions in the host country through childrearing. While these parents seek to secure better futures for their children through migration, they are confronted with continued anxieties and new challenges in passing on their newly achieved class status to the next generation. Their childrearing aspirations are also complicated by the changing geopolitical order with China's rise on the global stage. The paper contributes to a better understanding of middle-class migrant subjectivities and insecurities as well as of an emerging trend in reproduction-motivated migration from China.Accepted versionOER 09/20 YP