27 research outputs found

    Influence of Parental Expectations on Young Children’s Approaches to Learning

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    This study explores the level of young children’s Approaches to Learning (ATL) in Shanxi, China, with a specific on the impact of parental expectations on ATL. 360 parents with preschool-aged children were enlisted for a comprehensive questionnaire survey. Applying descriptive statistics, inferential statistics, correlation, and regression analyses on the data gathered revealed that children's ATL was moderate, with noticeable variations based on gender and age. Importantly, parental expectations were positively correlated with children's ATL and remained a significant predictor even when accounting for age and gender, highlighting the strong relationship between parental expectations and early learning development. &nbsp

    Electric-field-induced selective catalysis of single-molecule reaction

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    随着单分子电学检测技术的迅速发展,分子电子学的研究不再局限于分子电子学器件的构筑及其电学性质的测量,而且扩展到单分子尺度化学反应过程的探索。然而目前相关的研究仍然局限于理论计算方面,在单分子尺度上实时监测和调控化学反应的活性和选择性是化学领域的长期目标和挑战。针对这一挑战,洪文晶教授课题组与程俊教授课题组合作,自主研发了精密科学仪器,将单个有机分子定向连接在两个末端尺寸为原子级的电极之间,解决了化学反应中分子取向控制的问题.理论计算结果证实了定向电场可以有效地稳定化学反应的过渡态,从而降低反应能垒。该研究工作在化学化工学院洪文晶教授、程俊教授、能源材料化学协同创新中心(iChEM)刘俊扬副研究员的共同指导下完成,由硕士研究生黄晓艳、iChEM博士研究生唐淳、博士研究生李洁琼以及兰州大学的陈力川博士作为共同第一作者,化学化工学院师佳副教授、陈招斌高级工程师、夏海平教授和田中群教授,萨本栋微纳研究院杨扬副教授、环境与生态学院白敏冬教授以及兰州大学张浩力教授参与了研究工作的讨论并给予指导,博士后乐家波、博士研究生郑珏婷、张佩(已毕业)、李瑞豪、李晓慧也参与了研究工作。Oriented external electric fields (OEEFs) offer a unique chance to tune catalytic selectivity by orienting the alignment of the electric field along the axis of the activated bond for a specific chemical reaction; however, they remain a key experimental challenge. Here, we experimentally and theoretically investigated the OEEF-induced selective catalysis in a two-step cascade reaction of the Diels-Alder addition followed by an aromatization process. Characterized by the mechanically controllable break junction (MCBJ) technique in the nanogap and confirmed by nuclear magnetic resonance (NMR) in bottles, OEEFs are found to selectively catalyze the aromatization reaction by one order of magnitude owing to the alignment of the electric field on the reaction axis. Meanwhile, the Diels-Alder reaction remained unchanged since its reaction axis is orthogonal to the electric fields. This orientation-selective catalytic effect of OEEFs reveals that chemical reactions can be selectively manipulated through the elegant alignment between the electric fields and the reaction axis.This work was supported by the National Key R&D Program of China (2017YFA0204902), the National Natural Science Foundation of China (21722305, 21703188, 21673195, 21621091, 51733004, 51525303, and 91745103), the China Postdoctoral Science Foundation (2017M622060), and the Young Thousand Talents Project of China. 该工作得到国家自然科学基金委(21722305、21703188、21673195、51733004、51525303、91745103),国家重点研发计划课题(2017YFA0204902),中国博士后面上基金(2017M622060)的资助,以及固体表面物理化学国家重点实验室、醇醚酯化工清洁生产国家工程实验室、能源材料化学协同创新中心的支持

    High resolution bio- and chemostratigraphic framework at the Frasnian-Famennian boundary: Implications for regional stratigraphic correlation between different sedimentary facies in South China

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    © 2017 Elsevier B.V. As one of the “Big Five” mass extinctions in Phanerozoic, the Frasnian-Famennian (F-F) boundary event records the extinction of 40 % of marine invertebrate genera. The F-F boundary is defined by the first appearance of conodont Palmatolepis subperlobata as well as the abundant occurrences of Pa. ultima at the base of the Lower Pa. triangularis Zone. The F-F boundary is also broadly coincident with a positive excursion in carbon isotopes, suggesting the possible linkage between the perturbation of marine carbon cycle and the biotic crisis. However, the correlation between conodont biostratigraphy and carbon isotope chemostratigraphy has not been established yet, preventing the high-resolution regional stratigraphic correlation among different sedimentary facies. In this study, we studied the conodont biostratigraphy and analyzed carbonate carbon (δ13Ccarb) and organic carbon (δ13Corg) isotopes of the Baisha section in the Guangxi Province, South China. The first appearance of index conodont fossil Pa. subperlobata for the Lower Pa. triangularis Zone, i.e. the F-F boundary, is coincident with the onset of a 3‰ positive excursion in δ13Ccarb, while Pa. triangularis and Pa. subperlobata occur nearly simultaneously, but predate the disappearances of Pa. linguiformis and other typical Frasnian elements. In addition, a positive excursion in δ13Corg is associated with the decline of δ13Ccarb near the base of the Middle Pa. triangularis Zone, which is marked by the first appearance of Pa. delicatula. Another important Famenian element Pa. minuta, the index fossil for the Upper Pa. triangularis Zone, first appears when δ13Corg starts to decline. The offset between δ13Corg and δ13Ccarb excursions could be attributed to the oceanic anoxia (the Kellwasser Event) near the F-F boundary, followed by the mixing of surface and deep water in earliest Famenian. The high resolution bio- and chemostratigraphic framework can be used as the standard for regional stratigraphic correlation and identification of the F-F boundary in different depositional environments in South China. We propose that the F-F boundary can be identified from a conodont-poor carbonate section by the onset of the positive excursion in δ13Ccarb, whereas the F-F boundary in a non-fossiliferous siliciclastic section might be placed slightly below the positive excursion in δ13Corg

    Biostratigraphy and Chemostratigraphy Across the Lower Kellwasser Boundary in Laye Section, Guizhou Province

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    © 2018 Peking University. In order to study biostratigraphy and chemical stratigraphy during the Lower Kellwasser event, high resolution conodonts research and chemostratigraphic framework were carried out. The data reveals that the inorganic and organic carbon isotope have a significant positive excursion at the bottom of the Laye section. It is considered that the sample LY-8 is consistent with the Lower Kellwasser boundary. The main reason for the change of carbon isotope in this area is the increase of organic carbon burial, which is caused by the increase of marine primary productivity and anoxia environment possibly

    Generation of an induced pluripotent stem cell line (SJTUGHi001-A) from a patient with Retinitis Pigmentosa carrying c.77C > T mutation in RAX2 gene

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    Retinitis pigmentosa (RP) is a group of genetically heterogeneous retinopathy resulting in irreversible loss of vision. Mutations in RAX2 gene has been related to RP with mechanisms unclear. Here, we generated a human induced pluripotent stem cell (iPSC) line from peripheral blood mononuclear cells of a RP patient carrying c.77C > T mutation in RAX2 gene. This cell line was induced by integration-free episomal vectors and validated for pluripotency and differentiation capacity, which may serve as a model to study the role of RAX2 in RP pathogenesis

    Generation of an induced pluripotent stem cell line (SJTUGHi003-A) from a patient with Sorsby fundus dystrophy carrying c.484G>A mutation in TIMP3 gene

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    Sorsby fundus dystrophy (SFD) is a rare autosomal dominant disorder with macular dystrophy and severe visual loss. Mutations in TIMP3 gene has been related to SFD with mechanisms unclear. We have successfully reprogrammed the peripheral blood mononuclear cells (PBMCs) from an SFD patient carrying c.484G>A mutation in TIMP3 gene to induced pluripotent stem cells (iPSCs) and characterized their pluripotency and genetic stability. This line may serve as a useful tool to explore the role of TIMP3 in SFD pathogenesis

    Decoupling the Interfacial Catalysis of CeO<sub>2</sub>‑Supported Rh Catalysts Tuned by CeO<sub>2</sub> Morphology and Rh Particle Size in CO<sub>2</sub> Hydrogenation

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    Metal–oxide interfaces play a crucial role in catalyzing CO2 conversion, while comprehensively decoupling interfacial catalysis is challenging due to their structural complexity. Herein, Rh/CeO2 catalysts, whose interfacial structures are finely tuned by altering the CeO2 morphologies and Rh particle sizes, were employed for CO2 hydrogenation. The results reveal that the density of interfacial oxygen vacancies that varies with the CeO2 morphologies determines the catalytic activity, while the product selectivity strongly depends on the nature of supported Rh species. With a decrease in Rh particle size, the weakened metallicity results in the suppression of the Sabatier reaction and thus the low CH4 selectivity. Meanwhile, the enhanced reverse water–gas shift process that is more easily catalyzed than the Sabatier reaction contributes to the promotion of catalytic CO2 efficiency. Interestingly, the CH4 selectivity increases with the reaction temperature rise at fine Rh particles, which could be ascribed to the enhanced H-spillover effect at high temperatures. Spectroscopic results confirm CO2 hydrogenation proceeding through a redox mechanism to generate an adsorbed CO intermediate that either is further hydrogenated into CH4 with strong CO adsorption capacity/H-spillover effect or desorbs directly into CO
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