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Catalysis under shell： Improved CO oxidation reaction confined in Pt@h-BN core-shell nanoreactors

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Nano Research 2017年第4期10卷 1403-1412页

作者： Mengmeng Sun Qiang Fu Lijun Gao Yanping Zheng Yangyang Li mingshu chen Xinhe Bao State Key Laboratory of Catalysis iChEM Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Department of Chemical Physics University of Science and Technology of China Hefei230026 China State Key Laboratory of Physical Chemistry of Solid Surfaces Department of Chemistry Xiamen University Xiamen 361005 China

Core-shell nanostructures consisting of active metal cores and protective shells often exhibit enhanced catalytic performance, in which reactants can access a small part of the core surfaces through the pores in the shells. In this study, we show that Pt nanoparticles （NPs） can be embedded into few-layer hexagonal boron nitride （h-BN） overlayers, forming Pt@h-BN core-shell nanocatalysts. The h-BN shells not only protect the Pt NPs under harsh conditions but also allow gaseous molecules such as CO and 02 to access a large part of the Pt surfaces through a facile intercalation process. As a result, the Pt@h-BN nanostructures act as nanoreactors, and CO oxidation reactions with improved activity, selectivity, and stability occur at the core-shell interfaces. The confinement effect exerted by the h-BN shells promotes the Pt-catalyzed reactions. Our work suggests that two-dimensional shells can function as robust but flexible covers on nanocatalyst surfaces and tune the surface reactivity.

关键词： core-shell CO oxidation Pt hexagonal boron nitride nanoreactor

Chaotic dynamics of a carbon nanotube oscillator with symmetry-breaking

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Chaotic dynamics of a carbon nanotube oscillator with symmet...

中小学教师发展力指标体系结构模型研究——基于扎根理论的调查分析

第十二届多体动力学与控制暨第七届航天动力学与控制和第十...

作者： mingshu chen Zhen Wang Peijun Zhang Yang Wang Shaanxi International Joint Research Center for Applied Technology of Controllable Neutron Source School of Science Xijing University

Carbon nanotubes(CNTs) play an essential role in nanoelectromechanical applications. To use nanostructures in different applications, especially in nanoengineering, we should increase our understanding of the CNT’s mechanical properties by exploring its dynamical behaviors. So, in this paper, the chaotic properties of a single-walled carbon nanotube(SWCNT) system with cubic nonlinear damping and external excitation with a phase shift are studied. The local/infinity dynamics of the unperturbed system are explored by using the Poincare-Lyapunov compactification theory. Subsequently, the global dynamics of this SWCNT system with special parameters are presented. The analytic solutions of homoclinic/heteroclinic orbits are calculated. By using the Melnikov method, the criterion for chaos emerging in this periodically excited perturbed SWCNT system is obtained. Finally, the bifurcation diagram, Lyapunov exponent spectrum, Poincare sections and the homoclinic bifurcation surfaces are presented to verify the occurrence of chaos. The simulation results confirm the theoretical analysis.

关键词： CNT Chaos Melnikov method Infinity dynamics

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教育学术月刊 2023年第9期 18-26页

作者：陈名树宋善炎湖南师范大学教育科学学院湖南长沙410081 湖南师范大学教师教育学院湖南长沙410081

中小学教师发展所需的核心能力或动力,是当下教师教育研究的热点。基于经典扎根理论研究的程序,经过理论性抽样(数据收集)、实质性编码(数据处理)、理论性编码(理论构建),结合德尔菲专家函询,采用探索性因素分析和验证性因素分析进行验... 详细信息

中小学教师发展所需的核心能力或动力,是当下教师教育研究的热点。基于经典扎根理论研究的程序,经过理论性抽样(数据收集)、实质性编码(数据处理)、理论性编码(理论构建),结合德尔菲专家函询,采用探索性因素分析和验证性因素分析进行验证,建构“中小学教师发展五力结构模型”。该模型包含“教师认知力“”教师情感力”“教师意志力”“教师行动力”和“教师反思力”5个一级指标和11个二级指标,32个测评题项。五力结构模型可以作为测量工具,考量当今教师发展的状况,为进一步提升教师教育能力提供参考依据。

关键词：中小学教师发展力扎根理论结构模型

Effect of transcranial direct current stimulation on postoperative sleep disturbance in older patients undergoing lower limb major arthroplasty:a prospective,double-blind,pilot,randomised controlled trial

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General Psychiatry 2024年第2期37卷 224-233页

作者： Jie Yang mingshu Tao Rongguang Liu Jiaxing Fang Chunyan Li Dexian chen Qi Wei Xingyu Xiong Wenxin Zhao Wen Tan Yuan Han Hongxing Zhang He Liu Song Zhang Junli Cao Department of Anesthesiology The Affiliated Hospital of Xuzhou Medical UniversityXuzhouJiangsuChina Department of Anesthesiology Hospital of Chengdu University of Traditional Chinese Medicine&Traditional Chinese Medicine Hospital of Sichuan ProvinceChengduSichuanChina NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs&Jiangsu Province Key Laboratory of Anesthesiology&Jiangsu Key Laboratory of Applied Technology of Anesthesia and Analgesia Xuzhou Medical UniversityXuzhouJiangsuChina Department of Anesthesiology Eye&ENT Hospital of Fudan UniversityShanghaiChina Department of Anesthesiology&Clinical Research Center for Anesthesia and Perioperative Medicine&Huzhou Key Laboratory of Basic Research and Clinical Translation for Neuromodulation The Fifth School of Clinical Medicine of Zhejiang Chinese Medical University||Huzhou Central Hospital||The Affiliated Huzhou HospitalZhejiang University School of Medicine||Affiliated Central Hospital Huzhou UniversityHuzhouZhejiangChina Department of Anesthesiology Renji Hospital School of MedicineShanghai Jiao Tong UniversityShanghaiChina

Background Postoperative sleep disturbance(PSD)is a common and serious postoperative complication and is associated with poor postoperative outcomes.Aims This study aimed to investigate the effect of transcranial direct current stimulation(tDCS)on PSD in older patients undergoing lower limb major arthroplasty.Methods In this prospective,double-blind,pilot,randomised,sham-controlled trial,patients 65 years and over undergoing lower limb major arthroplasty were randomly assigned to receive active tDCS(a-tDCS)or sham tDCS(s-tDCS).The primary outcomes were the objective sleep measures on postoperative nights(N)1 and N2.Results 116 inpatients were assessed for eligibility,and a total of 92 patients were enrolled;47 received a-tDCS and 45 received s-tDCS.tDCS improved PSD by altering the following sleep measures in the a-tDCS and s-tDCS groups;the respective comparisons were as follows:the promotion of rapid eye movement(REM)sleep time on N1(64.5(33.5-105.5)vs 19.0(0.0,45.0)min,F=20.10,p<0.001)and N2(75.0(36.0-120.8)vs 30.0(1.3-59.3)min,F=12.55,p<0.001);the total sleep time on N1(506.0(408.0-561.0)vs 392.0(243.0-483.5)min,F=14.13,p<0.001)and N2(488.5(455.5-548.5)vs 346.0(286.5-517.5)min,F=7.36,p=0.007);the deep sleep time on N1(130.0(103.3-177.0)vs 42.5(9.8-100.8)min,F=24.4,p<0.001)and N2(103.5(46.0-154.8)vs 57.5(23.3-106.5)min,F=8.4,p=0.004);and the percentages of light sleep and REM sleep on N1 and N2(p<0.05 for each).The postoperative depression and anxiety scores did not differ significantly between the two groups.No significant adverse events were reported.Conclusion In older patients undergoing lower limb major arthroplasty,a single session of anodal tDCS over the left dorsolateral prefrontal cortex showed a potentially prophylactic effect in improving postoperative short-term objective sleep measures.However,this benefit was temporary and was not maintained over time.

关键词： sleep stimulation postoperative

In situ time-resolved FTIR investigation on the reaction mechanism of partial oxidation of methane to syngas over supported Rh and Ru catalysts

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Chinese Science Bulletin 2000年第24期45卷 2236-2240页

作者： WENG Weizheng chen mingshu YAN Qiangu WU Tinghua CHAO Zisheng LIAO Yuanyan WAN Huilin Department of Chemistry State Key Laboratory for Physical Chemistry of Solid Surfacesand Institute of Physical ChemistryXiamen UniversityXiamen 361005China Department of Chemistry Zhejiang Normal UniversityJinhua 321004China

In situ time-resolved FTIR spectroscopy was used to study the reaction mechanism of partial oxidation of methane (POM) to synthesis gas and the reaction of CH4/O2/He (2/1/45, molar ratio) gas mixture with adsorbed CO species over Rh/SiO2, Ru/γ-Al2O3 and Ru/SiO2 catalysts at 500-600℃. It was found that CO is the primary product of POM reaction over reduced and working state Rh/SiO2 catalysts. Direct oxidation of CH4 is the main pathway of synthesis gas formation over Rh/SiO2 catalyst. CO2 is the primary product of POM over Ru/γ-Al2O3 and Ru/SiO2 catalysts. The dominant reaction pathway for synthesis gas formation over Ru/γ-Al2O3 catalyst is via the reforming reactions of CH4 with CO2 and H2O. For the POM reaction over Rh/SiO2 and Ru/γ-Al2O3 catalysts, consecutive oxidation of surface CO species is an important pathway of CO2 formation.

关键词： partial oxidation of methane synthesis gas reaction mechanism in situ time-resolved FTIR ruthenium rhodium supported metal catalyst.

非计量Zn-Cr尖晶石中离子占位对催化合成气合成异丁醇中的关键作用

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化学进展 2022年第1期34卷 155-167页

作者：田少鹏任花萍陈明淑苗宗成谭猗生西京学院理学院西安市先进光电子材料与能源转换器件重点实验室西安710123 中国科学院山西煤炭化学研究所煤转化国家重点实验室太原030001

异丁醇是一种基本有机化工原料和燃料添加剂。从煤基或生物质合成气制异丁醇符合我国"贫油富煤"的能源结构,对于保障我国能源安全具有重要的现实意义。Zn-Cr基催化剂合成异丁醇具有寿命长、积碳少,产物分布简单的优点,被广泛应用于合成... 详细信息

异丁醇是一种基本有机化工原料和燃料添加剂。从煤基或生物质合成气制异丁醇符合我国"贫油富煤"的能源结构,对于保障我国能源安全具有重要的现实意义。Zn-Cr基催化剂合成异丁醇具有寿命长、积碳少,产物分布简单的优点,被广泛应用于合成异丁醇研究。本文总结了近年来合成气合成异丁醇的进展,重点介绍本课题组近几年在异丁醇合成过程中发现的非计量Zn-Cr尖晶石中离子占位对催化合成气合成异丁醇中的关键作用。首先概述了异丁醇的催化剂体系、合成工艺以及生成机理,然后介绍了促进阳离子在尖晶石结构中混乱分布的策略,包括调节Zn/Cr比例、煅烧温度、制备方法以及负载碱金属等,同时介绍了两种常用的定量检测尖晶石结构离子占位的方法。本课题组首次发现异丁醇产率与离子分布混乱程度呈近似直线关系,是因为离子占位强烈影响催化剂的物化性质。最后展望了异丁醇合成过程中的机遇和挑战,期望此文对能源化工、材料科学等相关学科的学者有一定的参考和启示作用。

关键词：异丁醇非计量尖晶石离子占位

MnO_(x)/Rh(111)模型表面的制备及其CO加氢催化性能研究

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厦门大学学报（自然科学版） 2023年第1期62卷 61-67页

作者：马靖凯李幻陈明树厦门大学化学化工学院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福建厦门361005

金属-氧化物载体界面在多相催化中起着至关重要的作用.本研究制备了MnO_(x)/Rh(111)模型表面,采用原位镜面反射红外吸收光谱(IRAS)、扫描隧道显微镜(STM)、俄歇电子能谱(AES)和低能电子衍射(LEED)对其进行表征,并考察其在真空高温退火... 详细信息

金属-氧化物载体界面在多相催化中起着至关重要的作用.本研究制备了MnO_(x)/Rh(111)模型表面,采用原位镜面反射红外吸收光谱(IRAS)、扫描隧道显微镜(STM)、俄歇电子能谱(AES)和低能电子衍射(LEED)对其进行表征,并考察其在真空高温退火处理下的稳定性和CO加氢催化性能.结果显示:在Rh(111)单晶上沉积了规整有序且热稳定性好的不同覆盖度的MnO_(x)薄膜,MnO_(x)在Rh(111)上逐层生长,并在亚单层时形成清晰的二维团簇;低覆盖度时MnO_(x)二维簇以MnO的形式优先生长在Rh(111)的台阶位,并大多呈三角形,在亚单层Rh-MnO_(x)界面周边估测的长度随MnO_(x)覆盖度呈火山型变化,在0.4~0.5 ML(单层)之间有最大值.Rh(111)表面上CO加氢反应主要生成甲烷,部分覆盖MnO_(x)后显著抑制甲烷的生成而乙醇的选择性显著提高,且MnO_(x)盖满单层以后表面的催化活性下降.这些结果表明Rh-MnO_(x)界面位点可能是CO加氢生成乙醇的活性中心.

关键词： MnO_(x)/Rh(111) 金属-氧化物界面反射红外吸收光谱扫描隧道显微镜 CO加氢

创始人人力资本与高技术新创企业创新:一个有调节的中介模型

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管理评论 2022年第6期34卷 90-102页

作者：关健邓芳陈明淑芮雪梅中南大学商学院长沙410083

本文研究了创始人人力资本对高技术新创企业创新的作用机制,重点分析了风险投资在两者间的中介作用,并将制度环境调节因素引入研究框架,构建了一个有调节的中介模型。通过对305家新三板上市高技术新创企业展开实证研究,本文得到以下结论... 详细信息

本文研究了创始人人力资本对高技术新创企业创新的作用机制,重点分析了风险投资在两者间的中介作用,并将制度环境调节因素引入研究框架,构建了一个有调节的中介模型。通过对305家新三板上市高技术新创企业展开实证研究,本文得到以下结论:第一,创始人较高的教育水平、较丰富的管理经验不仅能直接促进高技术新创企业进行技术创新,还能通过吸引风险投资间接促进技术创新。第二,创始人的创业经验对高技术新创企业创新具有直接的积极影响。第三,创始人的技术专长虽然对吸引风险投资具有显著的积极影响,却不直接影响高技术新创企业创新。进一步研究表明,创业或管理经验与技术专长的协同效应能显著促进高技术新创企业的创新水平。第四,制度环境地区差异对创始人人力资本对高技术新创企业创新的直接影响和间接影响均存在调节作用。

关键词：创始人人力资本风险投资制度环境高技术新创企业创新

宽波段原位红外吸收光谱在Pd/SiO_(2)和Cu/SiO_(2)催化剂上CO氧化中的应用

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Chinese Journal of Catalysis 2022年第8期43卷 2001-2009页

作者：翁雪霏杨双莉丁丁陈明树万惠霖厦门大学化学化工学院化学系固体表面物理化学国家重点实验室福建厦门361005 中国科学院苏州纳米技术与纳米仿生研究所纳米真空互联实验站江苏苏州215123

多相催化的原位表征通常采用各种表征手段分别测试,但由于不同表征方法原位池结构不同,导致分别测试的温度、反应气氛及催化剂状态不尽相同,特别是催化过程还存在温度、反应物和产物浓度梯度,不同原位表征方法获取的信息可能来自不同的... 详细信息

多相催化的原位表征通常采用各种表征手段分别测试,但由于不同表征方法原位池结构不同,导致分别测试的温度、反应气氛及催化剂状态不尽相同,特别是催化过程还存在温度、反应物和产物浓度梯度,不同原位表征方法获取的信息可能来自不同的表面态,此外一些表征方法还涉及到光子或电子等的影响,难以获得实际催化过程准确全面的信息.原位红外吸收光谱广泛应用于催化反应机理过程的动态表征,然而多相催化体系中的氧化物组分通常对1200 cm^(-1)以下的红外光有较强的吸收,且常规红外光源强度在低波数段迅速衰减,目前原位红外光谱研究大多局限于4000-900 cm^(-1)对催化剂表面吸附物种(包括反应中间体)的检测,难以将其应用于反应过程中催化活性组分自身变化的研究,如活性组分的氧化/还原、表面重构、活性组分与载体表面键合等,这些信息多位于1200-50 cm^(-1).基于模型催化剂表面厚度可控,近年来作者应用镜面反射红外吸收光谱在几个体系的研究中均实现了在一张红外光谱中同时获取表面吸附物种、表面变化和反应产物生成等关键信息.另一方面,氧化硅是常用的多相催化剂载体,其中硅溶胶易制成薄膜、稳定性好,钯和铜作为催化剂活性组分广泛应用于实际多相催化反应过程,且钯和铜的价态在催化反应中往往会发生动态变化,确认真实活性相是一个难题.本文通过自行研制的原位红外反应池及超薄样品制备方法,在常规氧化物负载的实际多相催化剂体系获得了4000-400 cm^(-1)范围内较高的红外光谱信号,实现了反应条件下在一张红外光谱同时监测反应物、产物、表面吸附物种和催化剂自身的变化.以商业上常用的Pd/SiO_(2)和Cu/SiO_(2)催化剂上CO氧化反应为例,利用宽波段原位红外光谱观察到Pd^(2+)-O(670,608 cm^(-1)),Cu^(+)-O(635 cm^(-1))和Cu^(2+)-O(595,535 cm^(-1))等氧化物的特征峰,并原位跟踪了CO氧化反应过程中Pd和Cu活性组分氧化/还原态的动态变化,进一步结合准原位X射线光电子能谱测试结果相互佐证,证实了钯和铜的氧化/还原.实验结果表明,Pd/SiO_(2)和Cu/SiO_(2)催化剂在CO氧化反应条件下,其活性组分分别以Pd^(0)和Cu^(+)稳定存在.综上,本文方法可以提供更为可信的催化剂结构和催化性能相关信息,为多相催化的原位表征提供了新机遇.

关键词：原位红外光谱 X射线光电子能谱多相催化 CO氧化钯铜