129 research outputs found
新工科背景下《互换性与技术测量》教学模式改革研究
针对当前《互换性与技术测量》课程教学中存在的知识点相对独立、教学过程与工程应用存在较大脱节、难以满足"新工科"背景下课程与知识创新的要求等问题,文章以成果产出为导向,开展课程内容的分层与归类,引入知识模块进行知识梳理与教学组织的重构,实现知识讲授、小组讨论、动手实践等教学环节的有机融合,完成教学闭环,提升案例教学效果。此研究可以较好地推动课程与知识创新,具有较好的实践意义。厦门理工学院2016年度教育教学改革与建设项目(JGY201601
Direct Fabrication of Ultrafine Electrospinning Nanofiber
采用装配有疏水铜网的新型喷头研究了超细纳米纤维的制备.静电纺丝实现之前,首先对铜网进行了疏水处理,并将其安装于喷头前端.静电纺丝过程中,聚合物溶液由精密注射泵输送至喷头处.安装于喷头的铜网可将管道内的聚合物溶液分成多股细流从铜网网孔中流出.从铜网网孔流出的溶液细流受电场力作用被拉伸成多股独立射流,并从喷头携带走聚集的正电荷.受铜网表面疏水性和射流间电荷排斥力的影响,从铜网喷射出的多股射流都将保持其独立的轨迹而不会产生聚集.疏水铜网有利于减小纺丝射流的初始直径,并获得均匀的超细纳米纤维.利用新型的电纺丝喷头成功制备了直径20~80 nM的聚氧化乙烯(PEO)和聚乙烯醇(PVA)超细纳米纤维.实验结果表明,超细纳米纤维的直径随着电纺丝溶液浓度的增加而变大.A novel spinneret assembled with Cu grid was presented in this paper to fabricate ultrafine nanofiber directly.Before electrospinning,hydrophobic treatment was performed on the Cu grid,which was then fixed at the front end of spinneret.During electrospinning,the polymer solution was transferred to the spinneret by the precise syringe pump.Through the holes in the Cu grid,polymer solution flow was divided into several smaller ones.The fine liquid flow from each hole of Cu grid was stretched into individual jets by the electric field force,and the liquid jets carried away the positive charges accumulated on the spinneret.Due to the hydrophobic treatment and the charge repulsive force between charged jets,liquid jets emanated from Cu grid kept their own tracks without aggregation.The initial diameter of liquid jet was greatly decreased by the Cu grid after hydrophobic treatment,and the smaller jet led to finer uniform nanofiber.Polyethylene oxide(PEO) and polyvinyl alcohol(PVA) ultrafine nanofiber with the diameter of 20—80 nm were fabricated by this novel spinneret,and the diameter of ultrafine nanofiber increases with the increase of polymer solution concentration.国家自然科学基金重点资助项目(51035002);国家自然科学基金资助项目(50875222
基于图像测量技术的位移检测系统的设计
介绍一种基于图像测量技术的位移检测系统。系统由AdnS9500芯片上的COMS图像传感器采集被测物体表面图像信息,再经过内置的dSP处理器,对采集的图像进行匹配运算,输出数字位移信息,通过SPI通信传递给AVr单片机,由AVr单片机再处理并实时显示输出。为了提高COMS图像传感器与被测物体表面的距离,设置了外加激光源及光学透镜组件,使COMS图像传感器与被测物体表面的距离达到10~15CM,并且得到较高的精度。系统能够很好的实现非接触测量的目的
Photochemical degradation of autochthonous dissolved organic matter from the culture media of Chlorella spp.
利用三维荧光光谱-平行因子分析(EEM-PArAfAC)手段结合吸收光谱分析,研究了小球藻指数期和稳定期培养液中溶解有机物(dOM)在秋季天然太阳辐射作用下的光降解动力学特征.结果表明,小球藻生长过程中除能产生短波激发类腐殖质组分C1(其荧光峰的激发/发射波长位置为240,335nM/406nM)及类蛋白质组分C3(225,275nM/334nM)外,还会形成长波激发类腐殖质组分C2(260,395nM/502nM),表明C2组分并非仅有传统认为的陆源属性,同时也具有自生源属性.稳定期培养液的吸收光谱在250~300nM范围内出现的肩峰,可用于指示水环境中现场自生源的贡献.不同生长时期培养液中dOM的吸收系数和荧光组分的降解动力学都符合一级反应方程.稳定期类腐殖质荧光组分(C1和C2)的光降解程度略高于指数期,但指数期类色氨酸组分(C3)的光降解程度略高于稳定期.经太阳辐照6d后,小球藻培养液的吸收系数A350及各荧光组分的平均损失率分别达到83.0%、84.0%、64.8%和80.0%,对应的半衰期只有1.6~5.0d,揭示出藻类自生来源的dOM具有很强的光化学降解活性.Fluorescence excitation-emission matrix spectroscopy (EEM) and absorption spectroscopy were applied to study the photobleaching of dissolved organic matter (DOM) from the culture media of Chlorella spp.during a six day natural solar radiation in October 2008.Samples from both exponential and stationary phases of algal growth were collected for the photodegradation experiment.The purpose was to investigate the photoreactivity of autochthonous DOM in aquatic environments.Parallel factor analysis (PARAFAC) revealed two humic-like (C1:240, 335 nm/406 nm; C2:260, 395 nm /502 nm) and one protein-like (C3: 225, 275 nm/334 nm) fluorescent components in the culture media.The presence of longer-wavelength-excited humic-like component C2 indicated that this typical ‘terrestrial’ component may also be derived from biological origin.The short-wavelength shoulders at 250--300 nm in the absorption spectra of stationary phase sample may be used as an indicator of in-situ chromophoric DOM (CDOM) production in aquatic environments.The photodegradation dynamics of absorption coefficient and all fluorescent components of DOM from both growth phases followed the first-order reaction process.The loss of humic-like components for stationary phase samples was slightly higher than those of exponential phase samples, while the protein-like component showed the reverse trend.After the six-day natural solar irradiation, the average loss of a350 and fluorescence intensity for C1, C2 and C3 was 83.0%, 84.0%, 64.8% and 80.0%, respectively, corresponding to a half-time between 1.6--5.0 days.These results demonstrated that algal-derived DOM is highly photoreactive and susceptible to photochemical degradation.国家重点基础研究发展计划(973)项目(No.2011CB409804);国家自然科学基金(No.40776041);中央高校基本科研业务费专项资金(No.201112G011)---
TLR4的表达与急性胆道梗阻时内毒素致小鼠肝脏损伤的关系
目的探讨急性胆道梗阻时内毒素损伤小鼠肝脏的机制及其与TLR4表达的关系。方法雄性C57BL/10J(WT)小鼠42只,随机分为生理盐水组(NS组,n=21)、内毒素处理组1(LPS1组,n=21),C57BL/10ScnJ(TLR4-/-)小鼠21只,为内毒素处理组2(LPS2组)。3组均行胆总管结扎术,LPS1、LPS2组小鼠于胆总管内注射LPS(8ng/μL,10ng/g体重),NS组注射同等剂量的生理盐水,术后6、12、24h采集标本,RT-PCR检测肝脏组织TLR4mRNA的表达情况,全自动生化分析仪检测血清ALT、TBIL、DBIL水平,ELISA法检测血清TNF-α、IL-6的水平。病理观察肝脏损伤情况,免疫组织化学染色观察肝脏NF-κB的表达。结果 LPS1组与NS组比较肝脏组织TLR4mRNA在6h时表达已有升高,于24h达高峰,ALT、TBIL各时点均明显升高(P<0.01),TNF-α、IL-6表达亦增高(P<0.01),LPS1病理损伤程度较NS组重,免疫组化显示术后24小时NF-κB在LPS1组可见肝细胞明显的核表达。LPS2组与LPS1组比较各血清学指标均明显下降,病理损伤减轻,24h时肝细胞NF-κB核表达较少。结论在急性胆道梗阻时LPS可以加重肝脏组织损伤和机体炎症反应,可能与TLR4的表达增高及NF-κB的表达有关。阻断LPS-TLR4信号通路可以减轻LPS引起的机体损伤
Anti-resonance features of destructive quantum interference in single-molecule thiophene junctions achieved by electrochemical gating
基于单个有机分子来构筑电子器件为电子器件微型化提供潜在技术方案。本研究发展了可集成电化学门控的单分子电子器件测试芯片技术和科学仪器方法,在实验和理论两个层面对具有相消量子干涉效应的噻吩衍生物分子器件的电输运过程进行了电化学调控研究,从而首次在室温下实现了对单分子电子器件中量子干涉效应的反共振现象的直接观测和调控,为制备基于量子干涉效应的新型分子材料和器件提供了全新的设计思路和策略。该研究充分展示了电化学调控技术在信息材料和器件领域的重要应用潜力,也体现了我校固体表面物理化学国家重点实验室在电化学研究和科学仪器研发领域的技术积累,以及面向科学前沿开展交叉学科探索的研究特色。
该研究工作是在洪文晶教授、上海电力大学陈文博教授、英国兰卡斯特大学Colin Lambert教授指导下完成的。化学化工学院博士生白杰和李晓慧为论文的共同第一作者,刘俊扬副研究员、师佳副教授、研究生唐永翔、刘帅、黄晓娟、谭志冰和萨本栋微纳研究院的杨杨副教授等也参与了研究工作。田中群教授和毛秉伟教授为该工作提供了重要指导。【Abstract】Controlling the electrical conductance and in particular the occurrence of quantum interference in single-molecule junctions through gating effects, has potential for the realization of high-performance functional molecular devices. In this work, we used an electrochemically-gated, mechanically-controllable break junction technique to tune the electronic behaviour of thiophene-based molecular junctions that show destructive quantum interference (DQI) features. By varying the voltage applied to the electrochemical gate at room temperature, we reached a conductance minimum that provides direct evidence of charge transport controlled by an anti-resonance arising from DQI. Our molecular system enables conductance tuning close to two orders of magnitude within the non-faradaic potential region, which is significantly higher than that achieved with molecules not showing DQI. Our experimental results, interpreted using quantum transport theory, demonstrate that electrochemical gating is a promising strategy for obtaining improved in-situ control over the electrical performance of interference-based molecular devices.This research was supported by the National Key R&D Program of China (2017YFA0204902), National Natural Science Foundation of China (21722305, 21673195, 21503179, 21703188), the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, Natural Science Foundation of Shanghai (17ZR1447100), Science and Technology Commission of Shanghai Municipality (14DZ2261000), China Postdoctoral Science Foundation (2017M622060) for funding work in Xiamen. It was also supported by EU Horizon 2020 project QuIET under grant agreement no. 767187EC FP7 ITN ‘MOLESCO’ project no. 606728 and UK EPSRC grants EP/N017188/1 and EP/M014452/1 and Leverhulme Trust (Leverhulme Early Career Fellowships no. ECF-2017-186 and ECF-2018-375) for funding instrumentation used in Lancaster. It was also supported by Hungarian and Czech Academies of Sciences (P2015-107) and Hungarian Research Foundation (OTKA 112034) for funding instrumentation used in Hungary. The authors thank Z.-Q. Tian and B.-W. Mao, Xiamen University, for useful discussions.
该工作获得科技部国家重点研发计划课题(2017YFA0204902),国家自然科学基金委优秀青年科学基金等项目(21722305、21673195、21703188、21503179)以及中国博士后科学基金(2017M622060)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
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
Identifying the Conformational Isomers of Single-Molecule Cyclohexane at Room Temperature
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
Transition from tunneling leakage current to molecular tunneling in single-molecule junctions
数十年来,半导体工业一直遵循基于“摩尔定律”所设定的发展蓝图,逐步提升集成电路芯片上晶体管的集成度和运行速度,减小器件尺寸。为探索这一尺寸极限,课题组基于机械可控裂结技术自主开发了具有飞安级电学测量和亚纳米级位移控制灵敏度的科学仪器,在国际上首次获取了一系列具有不同重复单元的寡聚苯乙炔类分子电导随电极间距的演变关系,并发现随着电极间距的缩小,器件电输运由通过分子器件电流占主导逐步转变到由隧穿漏电流占主导。对于本研究中具有最小尺寸的寡聚苯乙炔分子器件,其由于隧穿漏电流所制约的尺寸极限可小至0.66 nm,预示了有机分子器件在未来电子器件小型化方面具有重要的应用潜力。
这一研究工作是在化学化工学院洪文晶教授、萨本栋微纳研究院杨扬助理教授以及英国Durham University的MartinR. Bryce教授共同指导下完成的。能源材料化学协同创新中心iChEM Fellow刘俊扬博士为论文第一作者,博士研究生郑珏婷、李瑞豪和硕士研究生黄晓艳、唐永翔、皮九婵、本科生王飞等参与了研究工作。田中群教授、毛秉伟教授和师佳副教授为论文工作提供了重要指导。【Abstract】The tunneling leakage current will be a major quantum obstacle during
miniaturization in the semiconductor industry down to the scale of several
nanometers. At this scale, to promote charge transport and overcome the
tunneling leakage current between the source and drain terminals, molecular
electronic junctions offer opportunities by inserting molecules between these
two electrodes. Employing a series of oligo(aryleneethynylene) (OAE) molecules,
here we investigate the transition from tunneling leakage current to molecular
tunneling in the single-molecule devices using mechanically controllable break
junction (MCBJ) technique, and the transition distances of the OAE molecular
junctions were determined and even down to 0.66 nm for OAE2 molecular
junction, which demonstrates that the intrinsic charge transport properties of a
single-molecule device can be outstripped from the tunneling leakage current.
Consequently, molecular electronic devices show the potential to push the
ultimate limit of miniaturization to the scale of several angstroms.This work was supported by the National Key R&D Program of China (2017YFA0204902). This work was also generously supported by the Young Thousand Talent Project of China, the EC FP7 ITN “MOLESCO” project number 606728, the National Natural Science Foundation of China (nos. 21703188, 21673195, 21503179), and the China Postdoctoral Science Foundation (2017M622060).
该工作获得科技部国家重点研发计划课题(2017YFA0204902),国家自然科学基金委(21673195、21703188、21503179)以及中国博士后科学基金(2017M622060)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
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