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In-Situ HP-STM and Operando EC-STM Studies of Heterogeneous Catalysis at Interfaces

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Chinese Journal of Structural Chemistry 2022年第10期41卷 29-44页

作者： Lei Xie Chaoqin Huang zhaofeng liang Hongbing Wang Zheng Jiang Fei Song Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201000China University of Chinese Academy of Sciences Bejing 101000China

Heterogeneous catalysis taking place at solid interfaces plays a crucial role not only in industrial chemical production, energy conversion but also in fundamental research. The dynamic evolution of surface morphology and composition requires full understanding especially under realistic reaction conditions. To this end, conventional scanning tunneling microscopy(STM) has been integrated with high pressure cell and electrochemical cell, forming high pressure(HP) STM and electrochemical(EC) STM for the in-situ/operando characterization at solid-gas and solid-liquid interfaces with atomic resolution, respectively. In this review, we attempt to give a brief introduction to the development and working principle of these two techniques and subsequently summarize several representative progresses in recent days. The dynamic changes in active sites, surface reconstruction, absorbates alteration and products formation are directly characterized in a combination with other surface sensitive technologies. The correlation between surface structures and catalytic performance as well as the underlying mechanism can thus be unraveled, which provides insights into the rational design and optimization of catalysts.

关键词： HP-STM EC-STM heterogeneous catalysis in-situ operando interfaces

Operating characteristics analysis of a dual-excited full-wavelength piezoceramic ultrasonic transducer

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Chinese Journal of Acoustics 2017年第2期36卷 271-288页

作者： liang zhaofeng MO Xiping ZHOU Guangping Shenzhen Polytechnic Institute of Acoustics Chinese Academy of Sciences

A dual-excited full-wavelength piezoceramic ultrasonic transducer as a cascade of two half-wavelength sandwich piezoceramic transducers is *** relevant parameters＇ expressions of the figure of merit N for the transducer are derived,and the effects of the structure and material parameters of the transducer on its characteristics are further analyzed by numerical *** results show that when the two piezoceramic stacks are respectively located at the displacement nodes of their own half-wavelength transducers,or the two piezoceramic stacks have the same number of pieces in the case of a certain number of piezoceramic pieces,the figure of merit of the transducer can reach a *** increasing of the number of piezoceramic pieces in a fairly large range,the figure of merit of the transducer slightly decreases,but the force factor of the transducer increases *** metal materials of the transducer have little effect on its figure of *** it can be seen that the dual-excited full-wavelength transducer can effectively increase the volumes of the piezoceramic stacks in the case of that the transducer＇s comprehensive performance has only a little bit of degradation,so it＇s power capacity and load capability can be dramatically improved,which means the transducer is more suitable for high power and heavy load applications.

关键词： transducer excited figure merit sandwich ultrasonic cascade pieces fairly piezoelectric

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不同铜线芯直径超声波焊接头性能的研究

兵器材料科学与工程 2024年第5期47卷 8-12页

作者：沈中华张永祺赵伦龚涛梁召峰许龙周光平 Md Shafiqul Islam 广西高校先进制造与自动化技术重点实验室广西桂林541006 深圳职业技术大学超声技术研究所广东深圳518055 瑞典布京理工学院机械学院布莱金厄卡尔斯克鲁纳37179

对3种不同的线芯直径的10 mm双铜(Cu)导线接头进行超声波焊接试验。通过剥离试验、孔隙率计算、温度测量、扫描电子显微镜(SEM)研究分析了铜导线接头性能和失效形式。结果表明:线芯直径与接头抗剥离力正相关,线芯直径越粗接头力学性能... 详细信息

对3种不同的线芯直径的10 mm双铜(Cu)导线接头进行超声波焊接试验。通过剥离试验、孔隙率计算、温度测量、扫描电子显微镜(SEM)研究分析了铜导线接头性能和失效形式。结果表明:线芯直径与接头抗剥离力正相关,线芯直径越粗接头力学性能越好。两根线芯直径为0.1 mm导线焊接的接头抗剥离强度未达标,失效形式为结合面完全分离无线芯断裂。直径增至0.2 mm时,接头抗剥离强度均达到标准,失效形式变为结合面处线芯的韧性断裂。焊接时的峰值温度有效影响了接头孔隙率,但孔隙率并不能完全作为判断接头成型质量的依据,部分导线在高温下仅发生塑性变形,而未能实现原子键合。此外,通过观察接头剖面发现,焊接接头形成了外紧内松的结构,与压块接触的接头上侧和与焊头接触的接头下侧几乎无空隙,而接头中间内侧则存在大量空隙。

关键词：超声波焊接铜导线力学行为断口形貌

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临床生化检验学混合教学模式的构建及应用

中国高等医学教育 2024年第2期 60-61页

作者：马洁梁照锋王佳李大众钱晖龚爱华江苏大学医学院江苏镇江212013 镇江市京口区健康路社区卫生服务中心江苏镇江212001

教学团队依托中国大学MOOC平台,搭建了临床生化检验学在线课程。在此基础上,构建了“在线课程学习-临床案例收集-PBL研讨-课后健康教育”的线上线下混合式教学模式。在这个过程中,解决了教与学过程中存在的4个脱节,实现了3个层次的整合... 详细信息

教学团队依托中国大学MOOC平台,搭建了临床生化检验学在线课程。在此基础上,构建了“在线课程学习-临床案例收集-PBL研讨-课后健康教育”的线上线下混合式教学模式。在这个过程中,解决了教与学过程中存在的4个脱节,实现了3个层次的整合,最终目的是培养医学生自主学习和终身学习的能力。

关键词：混合式教学模式临床生化检验学中国大学MOOC

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Role of local coordination in bimetallic sites for oxygen reduction: A theoretical analysis

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Journal of Energy Chemistry 2020年第5期29卷 131-137页

作者： Yuqi Yang Hao Zhang zhaofeng liang Yaru Yin Bingbao Mei Fei Song Fanfei Sun Songqi Gu Zheng Jiang Yuen Wu Zhiyuan Zhu Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201204China Shanghai Synchrotron Radiation Facility Zhangjiang LaboratoryShanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China University of Chinese Academy of Sciences Beijing 100049China Department of Chemistry Hefei National Laboratory for Physical Sciences at the MicroscaleiChEM(Collaborative Innovation Center of Chemistry for Energy Materials)University of Science and Technology of ChinaHefei 230026AnhuiChina ShanghaiTech University Shanghai 201210China

Understanding of the oxygen reduction reaction(ORR)mechanism for single atom catalysts is pivotal for the rational design of non-precious metal cathode materials and the commercialization of fuel ***,a series of non-precious metal electrocatalysts based on nitrogen-doped bimetallic(Fe and Co)carbide were modeled by density functional theory calculations to predict the corresponding reaction *** study elucidated prior oxygen adsorption on the Fe atom in the dual site and the modifier role of Co atoms to tune the electronic structures of *** reaction activity was highly correlated with the bimetallic center and the coordination environment of the adjacent ***,the preadsorption of*OH resulted in the apparent change of metal atoms'electronic states with the d-band center shifting toward the Fermi level,thereby boosting reaction *** result should help promote the fundamental understanding of active sites in ORR catalysts and provide an effective approach to the design of highly efficient ORR catalysts on an atomic scale.

关键词： Non-precious metal catalysts Bimetallic-sites Oxygen reduction reaction Density functional theory

Identifying the convergent reaction path from predesigned assembled structures: Dissymmetrical dehalogenation of Br_(2)Py on Ag(111)

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Nano Research 2021年第12期14卷 4704-4713页

作者： Jinping Hu zhaofeng liang Kongchao Shen Lei Xie Huan Zhang Chaoqin Huang Yaobo Huang Han Huang Jianxin Tang Zheng Jiang Miao Yu Fei Song Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai201000China University of Chinese Academy of Sciences Beijing100100China Shanghai Synchrotron Radiation Faciality Zhangjiang LaboratoryShanghai Advanced Research InstituteChinese Academy of SciencesShanghai201000China Institute of Functional Nano&Soft Materials(FUNSOM) Soochow UniversitySuzhou215123China School of Physics Science and Electronics Central South UniversityChangsha410083China State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001China

On-surface Ullmann coupling has been intensely utilized for the tailor-made fabrication of conjugated frameworks towards molecular electronics, however, reaction mechanisms are still limitedly understood. Herein, we provide a comprehensive elucidation of the surface Ullmann coupling of 2,7-dibromopyrene (Br2Py) on Ag(111) by scanning tunnelling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and density function theory (DFT), and reveal that the Ullmann reaction path is unique regardless of predesigned assembled structures. By manipulating deposition conditions, diverse assembled architectures have been constructed for Br2Py on Ag(111), including the ladder phase, parallel arrangement, hexagonal patterns from monomers or Kagome lattices based on organometallic (OM) dimers. Intriguingly, stepwise annealing leads to an identical reaction diagram for the surface Ullmann coupling from individual assembled structures convergent into the brick-wall-pattern OM dimers first, which is deemed to be a stable phase, and then into elongated OM chains in order and eventually long-range polymers with direct C-C coupling. While the reaction mechanism is demonstrated to be dominated by the metal coordinated and halogen bonding motifs, interestingly, it has also been revealed that surface adatoms and dissociated Br atoms play a crucial role in coupling reactions. In contrast to previous reports demonstrating the manipulation of Ullmann reactions by preassembled strategy, herein, weak intermolecular interaction in assembled nanostructures is immediately suppressed by strong covalent bonding during reactions. Importantly, our report proposes essential insights on fundamental understanding of surface Ullmann coupling towards high-yield surface synthesis.

关键词： self-assembly Ullmann coupling organometallic intermediates reaction path scanning tunneling microscopy

Vibration analysis of ultrasonic tubular resonators

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Chinese Journal of Acoustics 2012年第1期31卷 59-72页

作者： liang zhaofeng MO Xiping ZHOU Guangping Department of Electronic Engineering Shenzhen Polytechnic Shenzhen 518055 Institute of Acoustics Chinese Academy of Sciences Beijing 100190 Graduate University of Chinese Academy of Sciences Beijing 100190

The frequency equation of the axisymmetric coupled vibration of a ultrasonic tubular resonator with both ends free is derived by an exact solution method, based on classical Fliigge thin shell theory. The dependence of the dimensionless frequency Ω on the ratio of length to radius 1/a, the ratio of radius to thickness a/h and Poisson＇s ratio v is investigated, and the axisymmetric coupled vibration of the ultrasonic tubular resonator with both ends shear diaphragm is compared with that with both ends free. The accuracy of two-dimensional and three-dimensional apparent elasticity method is also assessed by the comparison with the exact solution method. Finally, the mode shapes of the ultrasonic tubular resonator are calculated by the exact solution method, and its transform efficient is analyzed. The results show that as for two boundary conditions of both ends free and both ends shear diaphragm, the difference of the effect of the boundary conditions on the dimensionless frequency of the axisymmetric coupled vibration of the ultrasonic tubular resonator becomes smaller as l/a increases, and the larger a/h, the smaller the difference. Moreover, for free-free boundary conditions, the change of a/h has nearly no effect on the dimensionless frequency of the thin tubular resonator usually considered to mean a/h 〉 10. Purthermore, the dimensionless frequency Ω decreases as v in- creases for a given l/a, and the impact of v on Ω is different for different l/a, and the maximum impact will appear when l/a = π. Finally, the study also shows the three-dimensional apparent elasticity method has very high accuracy.

关键词：谐振器超声波振动分析自由边界条件频率方程耦合振动弹性方法无量纲

双激励全波长压电陶瓷超声换能器工作特性分析

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声学学报 2017年第4期42卷 385-396页

作者：梁召峰莫喜平周光平深圳职业技术学院深圳518055 中国科学院声学研究所北京100190

对由两个半波长夹心式压电陶瓷换能器级联而成的双激励全波长压电陶瓷超声换能器进行了研究,给出了这种换能器优值的相关参量表达式,通过数值计算分析了该换能器的结构和材料参数对其特性的影响。研究结果表明,当两组压电陶瓷堆分别位... 详细信息

对由两个半波长夹心式压电陶瓷换能器级联而成的双激励全波长压电陶瓷超声换能器进行了研究,给出了这种换能器优值的相关参量表达式,通过数值计算分析了该换能器的结构和材料参数对其特性的影响。研究结果表明,当两组压电陶瓷堆分别位于各自所在半波长换能器的位移节点,或者在压电陶瓷片数量确定情况下两组压电陶瓷堆的片数相同时,换能器均能得到最大的优值;在相当大的范围内增加压电陶瓷片的数量,换能器的优值稍有降低,但力因子迅速增大;金属块材料对换能器的优值影响甚微。可见双激励全波长换能器能在不明显降低换能器综合性能的情况下有效增加压电陶瓷的体积,因而可大幅提高换能器的功率容量和负载能力,更适用于大功率重负载的场合。

关键词：超声换能器金属块负载能力重负载压电片功率超声位移曲线功率容量特性分析机电耦合系数

Exosomes in bladder cancer:novel biomarkers and targets

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2021年第5期22卷 341-347,I0001页

作者： Hao GENG Qingchen ZHOU Wenhao GUO Ling LU liangkuan BI Yi WANG Jie MIN Dexin YU zhaofeng liang Department of Urology the Second Affiliated Hospital of Anhui Medical UniversityHefei 230032China Department of Urology the First Affiliated Hospital of University of Science and Technology of ChinaDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230001China Jiangsu Key Laboratory of Medical Science and Laboratory Medicine School of MedicineJiangsu UniversityZhenjiang 212013China Department of Child Healthcare Women and Children Health Hospital of ZhenjiangZhenjiang 212001China

Exosomes are nanometer-sized vesicles that contain various types of biologically active components,including proteins,nucleic acids,carbohydrates,and lipids,which vary with the type and physiological state of the *** recent years,several studies have showed that exosomes can provide new non-invasive diagnostic and prognostic biomarkers in patients affected by cancers,including bladder cancer(BC),and the lipid bilayer membrane structure makes exosomes as promising delivery vehicles for therapeutic *** have the characteristics of high abundance,high stability,tissue specificity,and wide distribution in body fluids,and are secreted as various types by cells in different states,thereby possessing great potential as biomarkers for ***,we briefly summarize the functions and roles of exosomes in the occurrence and development of BC and the current progress of research on exosomes in BC,while focusing on potential clinical applications of the diagnosis,treatment,and prognosis of BC.

关键词： Exosome Bladder cancer Function Clinical application Biomarker