51 research outputs found

    我国油料产业形势分析与发展对策

    Get PDF
    油料安全事关国计民生,保障油料有效供给是我国必须坚守的国家粮食安全底线。站在全球视角,对2011/2012—2020/2021年度我国油料供需形势、生产形势及市场形势进行分析,明确我国油料产业在生产、加工、贸易等方面面临的挑战,并针对性地提出了统一科学谋划与增强政策扶持精准度相结合,强化科技支撑与耕地资源保护相结合,提高农户油料种植收益与增强自然灾害抵御能力相结合,坚持大宗油料品牌建设与特色油料资源开发相结合,稳定当前农业合作伙伴关系与扩宽油料进口来源相结合,实施差异化市场监管与引导居民科学消费相结合等发展对策,以期为促进油料生产、保障植物油有效供给、降低植物油对外依存度,维护国家粮油安全提供参考。 Oilseed security is related to national economy and people′s livelihood, and ensuring the effective supply of oilseeds is the bottom line of national food security that China must adhere to. From a global perspective, the supply and demand situation, production situation and market situation of oilseeds in China for the period of 2011/2012-2020/2021 were analyzed, further the challenges faced by China′s oilseed industry in terms of production, processing and trade were clarified, and six development countermeasures ,including the combination of unifying scientific planning and enhancing the accuracy of policy support, the combination of strengthening scientific and technological support and protecting arable land resources, the combination of improving farmers′ income from oilseed planting and enhancing natural disaster resistance, the combination of insisting on the brand building of bulk oilseed and developing characteristic oilseed resource, the combination of stabilizing the current agricultural industry cooperative partnership and expanding sources of oilseed imports, and the combination of implementing differentiated market supervision and guiding residents′ scientific consumption,were put forward, in order to provide a reference for promoting oilseed production, ensuring effective supply of vegetable oil, reducing external dependence of vegetable oil and maintaining national food and oil security

    Identifying the Conformational Isomers of Single-Molecule Cyclohexane at Room Temperature

    Get PDF
    构象异构是化学中的基本问题。然而对于环己烷等柔性分子,由于其在室温下极快的互变异构过程,基于系综的表征方法(如核磁等)只能得到所有构象平均贡献的结果。为了应对这一挑战,化学化工学院洪文晶教授与夏海平教授课题组为在室温条件下对柔性分子构象的定量分析与表征这一挑战,课题组成功实现了在室温条件下对环己烷两种椅式构象的电学表征与比例识别。同时,通过纳米电极间隙对分子的限域作用,发现在宏观尺度下极不稳定的扭船式中间体得以在单分子尺度稳定存在,这为不稳定中间体的研究提供了重要表征方法。 这一研究工作是在化学化工学院洪文晶教授、夏海平教授共同指导下完成的,iChEM直博生唐淳与化工系研究生唐永翔为论文共同第一作者。师佳副教授与刘俊扬副研究员为该工作提供了指导,博士后陈志昕、博士研究生陈李珏以及研究生叶艺玲、严哲玮、张珑漪共同参与了该工作。【Abstract】Isomerism reflects the ubiquitous nature that molecules with the same molecular formula show different structures. The interconversion between conformational isomers of flexible molecules is quite fast owing to the low barriers of around 10 kcal mol−1, leading to average signal contributed by all the possible isomers characterized by ensemble methods. On this account, identifying the conformational isomers of flexible molecules at room temperature has a substantial challenge. Here, we develop a single-molecule approach to identify the conformational isomers of cyclohexane at room temperature through the single-molecule electrical characterization. By noise analysis and feature extraction of the conductance of single-molecule junctions, we quantificationally identified two chair isomers of cyclohexane at room temperature, while such identification is only feasible at low temperatures by ensemble characterization. The strategy to apply the single-molecule approach to identify conformational isomers paves the avenue to investigate the isomerization of flexible molecules beyond the ensemble methods.This work was supported by the National Natural Science Foundation of China (nos, 21722305, 21673195, 21703188, and U1705254), the National Key R&D Program of China (2017YFA0204902), China Postdoctoral Science Foundation (no. 2017M622060), and the Fundamental Research Funds for Xiamen University (20720190002).该工作获得了科技部国家重点研发计划、国家自然科学基金等项目的资助,也得到了固体表面物理化学国家重点实验室、能源材料化学协同创新中心的支持

    Room-temperature quantum interference in single perovskite quantum dot junctions

    Get PDF
    钙钛矿材料由于其高量子产率、载流子迁移率和独特的光致发光特性而在光电材料领域存在诸多潜在的重要应用。研究钙钛矿材料在纳米尺度下电荷输运的独特尺寸效应对钙钛矿光电器件的设计和开发具有重要的指导意义。洪文晶教授课题组基于机械可控裂结技术自主研发了具有皮米级位移调控灵敏度和飞安级电学测量精度的精密科学仪器,对南开大学李跃龙副教授团队合成的钙钛矿量子点进行了深入表征,研究工作成功将量子干涉的研究体系拓展至在光电领域具有重要应用的钙钛矿材料领域,为未来制备基于量子干涉效应的新型钙钛矿器件提供了一种全新的思路。 这一跨学科国际合作研究工作是在化学化工学院洪文晶教授、英国Lancaster 大学物理系Colin J. Lambert教授以及南开大学电子信息与光电工程学院李跃龙副教授的共同指导下完成的。化工系硕士研究生郑海宁、Lancaster University大学Songjun Hou博士、南开大学硕士研究生辛晨光为论文第一作者。博士后林禄春,博士研究生谭志冰、郑珏婷,硕士研究生蒋枫、张珑漪,本科生何文翔、李庆民等参与了论文的研究工作。刘俊扬特任副研究员、师佳副教授和萨本栋微纳米研究院杨扬副教授也参与了部分指导工作。The studies of quantum interference effects through bulk perovskite materials at the Ångstrom scale still remain as a major challenge. Herein, we provide the observation of roomtemperature quantum interference effects in metal halide perovskite quantum dots (QDs) using the mechanically controllable break junction technique. Single-QD conductance measurements reveal that there are multiple conductance peaks for the CH3NH3PbBr3 and CH3NH3PbBr2.15Cl0.85 QDs, whose displacement distributions match the lattice constant of QDs, suggesting that the gold electrodes slide through different lattice sites of the QD via Auhalogen coupling. We also observe a distinct conductance ‘jump’ at the end of the sliding process, which is further evidence that quantum interference effects dominate charge transport in these single-QD junctions. This conductance ‘jump’ is also confirmed by our theoretical calculations utilizing density functional theory combined with quantum transport theory. Our measurements and theory create a pathway to exploit quantum interference effects in quantum-controlled perovskite materials.This work was supported by the National Key R&D Program of China (2017YFA0204902, 2014DFE60170, 2018YFB1500105), the National Natural Science Foundation of China (Nos. 21673195, 21503179, 21490573, 61674084, 61874167), the Open Fund of the Key Laboratory of Optical Information Science & Technology (Nankai University) of China, the Fundamental Research Funds for the Central Universities of China (63181321, 63191414, 96173224), and the 111 Project (B16027), the Tianjin Natural Science Foundation (17JCYBJC41400), FET Open project 767187—QuIET, the EU project BAC-TO-FUEL and the UK EPSRC projects EP/N017188/1, EP/M014452/1. 该工作得到国家重点研发计划课题(2017YFA0204902)、国家自然科学基金(21673195、21503179、21490573)、厦门大学“人工智能分析引擎”双一流重大专项等项目的资助,也得到了固体表面物理化学国家重点实验室、能源材料化学协同创新中心的支持

    钛合金表面织构化与构建生物活性涂层的研究进展

    No full text
    医用钛合金作为临时基质的植入材料对周围新组织的生长具有特殊的诱导作用。针对椎弓根螺钉固定系统对钛合金基材表面机械性能和生物活性的共同需求,表面织构与生物活性涂层对钛合金表面的改性展示出独特的优越性。文中详细介绍了钛合金表面织构化对其摩擦学性能和生物相容性的影响,以及构建生物活性涂层的种类;总结了钛合金表面织构的作用机理,生物活性涂层的改善机制,阐述了表面织构化与构建生物活性涂层各自的局限性,并指出钛合金作为生物医用材料仍需要解决的问题及未来的研究趋势

    基于聚倍半硅氧烷改性的耐高温涂料及其应用

    No full text
    本发明公开了一种基于聚倍半硅氧烷改性的耐高温涂料及其应用。在一些实施例中,所述耐高温涂料包含按照质量百分比计算的如下组分:改性有机树脂15%~30%,改性颜填料25%~50%,分散剂1%~5%,流平剂0.1%~3%,复合助剂0.2%~3%,溶剂3%~20%。本发明通过使用聚倍半硅氧烷作为改性剂对成膜树脂和颜填料进行改性,可以进一步提升耐高温涂料的品质,并有效提高涂层的综合性能,特别是能大幅提升涂层在高温条件下的硬度、稳定性、抗划伤能力、致密性和抗开裂性能

    雄安新区植物名录数据集

    No full text
    本文通过对雄安新区持续一年的多次网格式实地调查,结合现场记录物种名称、拍照凭证,部分物种采集标本凭证等多种方法,整理出最新的雄安新区植物名录。采用最新的基于分子标记的分类系统,即APGIV系统,统计出雄安新区共有维管植物104科371属641种。在调查结果的基础上按类型进行分类分析得出,雄安新区的维管植物中有珍稀保护植物27种;乡土植物304种;水生植物87种;外来入侵植物44种;木本植物149种;经济作物81种;园林花卉206种。雄安新区植物名录数据集可以为雄安新区植物多样性的研究和保护提供数据支持,对雄安新区在植物造林、园林绿化、珍稀物种保护、外来入侵植物防治等方面工作起到良好的参考和指导作用

    石墨烯/聚酯/环氧粉末涂层耐腐蚀性研究

    No full text
    将聚酯树脂与环氧树脂分别与石墨烯干粉在160℃不锈钢反应锅中高速熔融混合,制得石墨烯/聚酯预分散体、石墨烯/环氧预分散体,然后将该预分散体与树脂、颜料、填料、助剂进行物理预混合与熔融挤出混合,经由粉碎、分级后,得到含有石墨烯成分的防腐性粉末涂料。涂层性能测试结果表明:石墨烯的加入能够显著提高涂层的防腐蚀性能,尤其是耐盐雾性能超过1 000 h,同时耐老化性能也有显著改善。另外,通过试喷涂制作样片时,发现粉末涂料的穿透性和上粉性能都得到很大提高

    基于移动粒子半隐式法(MPS)电动汽车减速器最佳润滑油量分析

    No full text
    在分析某电动汽车减速器内元件的产热与传热过程的基础上,建立了基于AMEsim软件某电动汽车减速器热网络仿真模型,假设在充分润滑情况下,完成了高温高负荷不同车速工况条件下的减速器热平衡仿真。应用移动粒子半隐式法(MPS)分析了不同润滑油油量时减速箱的搅油流场,在此基础上,对减速器热网络模型中的对流换热热阻模块进行修正,分析得出减速器最佳润滑油油量。修正结果表明,电动汽车减速器在高温高负荷工况下,较少的润滑油油量会导致减速器齿轮系处于欠润滑状态,致使齿面温度较高。将热网络法与移动粒子半隐式法(MPS)相结合,为电动汽车减速器润滑效果分析提供了一种新方法
    corecore