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基于实验室光源的透射X射线纳米分辨显微镜研制
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作者 廖可梁 何其利 +6 位作者 宋杨 李荣刚 宋茂华 李盼云 赵海峰 刘鹏 朱佩平 《物理学报》 SCIE EI CAS CSCD 北大核心 2024年第17期66-74,共9页
透射X射线显微镜(transmission X-ray microscope,TXM)是高精密度的尖端X射线成像设备,是现代科学技术的结晶,可以在纳米尺度上进行无损成像,为物理学、生命科学、材料学和化学等领域的众多科学问题提供了有力的研究工具.虽然国内外很... 透射X射线显微镜(transmission X-ray microscope,TXM)是高精密度的尖端X射线成像设备,是现代科学技术的结晶,可以在纳米尺度上进行无损成像,为物理学、生命科学、材料学和化学等领域的众多科学问题提供了有力的研究工具.虽然国内外很多同步辐射装置都建立了以TXM为核心的纳米CT实验站,但是目前国际上只有个别企业能提供商业化的实验室TXM.究其原因,主要是该仪器涉及众多高难度的工程技术问题,诸如:高亮度实验室X射线源、高分辨率X射线光学元器件、高精度样品台、高灵敏度探测器、仪器对温度和振动等环境因素的超高要求等.为了提高研发高端X射线成像仪器的水平,需要逐个突破在研发X射线纳米CT过程中遇到的技术瓶颈.本文主要讨论了工作能量为5.4 keV的实验室TXM的仪器设计,以及全场成像实验结果.该仪器工作在吸收衬度模式下,成像视野达到了26μm,可以对30 nm线宽的特征结构实现清晰的成像,西门子星测试卡的功率谱曲线表明该仪器具有分辨半周期为28.6 nm线对结构的潜力. 展开更多
关键词 X 射线成像 X 射线显微镜 科学仪器
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BLUF蛋白TePixD Y8F突变体的结构
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作者 胡睿行 周雅琳 +2 位作者 林霖 丁蓓 陆青 《生物化学与生物物理进展》 SCIE CAS CSCD 北大核心 2024年第2期459-467,共9页
目的TePixD(Tll0078)是一种来自细长嗜热聚球藻(Thermosynechococcus elongatus BP-1)的blue light-using flavin(BLUF)感光蛋白。TePixD蛋白在FAD口袋周围有一个保守的Tyr8-Gln50-Met93三联体,以介导质子偶联电子转移(proton-coupled e... 目的TePixD(Tll0078)是一种来自细长嗜热聚球藻(Thermosynechococcus elongatus BP-1)的blue light-using flavin(BLUF)感光蛋白。TePixD蛋白在FAD口袋周围有一个保守的Tyr8-Gln50-Met93三联体,以介导质子偶联电子转移(proton-coupled electron transfer,PCET)过程。但具体的光响应机制有待进一步研究。本文的目的是解析TePixD在光响应关键位点突变体的结构以及生化性质,以此分析TePixD的光响应过程。方法利用X射线衍射法解析TePixD Y8F突变体的晶体结构,Tyr8侧链在PCET过程中有重要作用,而突变体Phe8的侧链失去了羟基从而使分子无法介导PCET。本文比较了TePixD野生型和Y8F突变体之间的结构,并比较了同蛋白家族的SyPixD Y8F与TePixD Y8F的结构。此外,使用多角度光散射法分析几种TePixD在光响应关键位点突变体(Y8F、Q50L、W91F、Y8F/W91F和Q50L/W91F)在溶液中的生化特性。结果本文以2.54Å分辨率解析了TePixD Y8F突变体的晶体结构,发现其与TePixD野生型的整体结构相似,而与SyPixD Y8F存在显著差异。生化分析表明,对比黑暗和光照条件时,TePixD突变体与野生型的分子质量变化以及洗脱峰表现出差异,表明突变体对光诱导蛋白质构象变化产生干扰。结论本文的结构测定和生化分析为揭示BLUF蛋白的光响应机制提供了新信息。 展开更多
关键词 TePixD 光感受器 寡聚体 光响应
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X射线自由电子激光与金属钌相互作用双温模型的数值分析
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作者 海雪 张斐斐 +3 位作者 温阿利 殷亚茹 任翠兰 怀平 《核技术》 EI CAS CSCD 北大核心 2024年第7期15-24,共10页
金属钌(Ru)具有优异的力学性能和化学稳定性,同时具有高反射率、较大临界角等优异性能,是自由电子激光装置中光学元件的候选镀层材料之一。本文对X射线自由电子激光(X-ray Free-electron Lasers,XFEL)脉冲与金属钌薄膜相互作用过程进行... 金属钌(Ru)具有优异的力学性能和化学稳定性,同时具有高反射率、较大临界角等优异性能,是自由电子激光装置中光学元件的候选镀层材料之一。本文对X射线自由电子激光(X-ray Free-electron Lasers,XFEL)脉冲与金属钌薄膜相互作用过程进行了模拟,采用数值方法求解双温模型(Two-temperature Model,TTM),得到了电子和晶格温度随时间的演化规律。获得激光的脉冲宽度、能量密度、穿透深度、材料的电声子耦合系数等对激光与金属钌相互作用过程中热效应的影响规律。通过对X射线自由电子激光脉冲与金属相互作用过程的双温模型数值解,可以获得材料中电子和晶格温度随时间的演化规律,并探究光源的参数对其热传输过程的影响。研究发现,金属钌晶格平衡温度与能量密度呈正相关;金属钌电子最高温度随脉冲宽度的增加而降低;金属钌的晶格平衡温度随穿透深度的减小而增加,最终趋于稳定;电子-声子平衡时间与电声子耦合系数呈负相关。本文获得X射线自由电子激光脉冲与金属钌相互作用的相关数据及基本演化规律,有助于进一步理解金属钌在激光辐照作用下材料的热效应演化机制,为自由电子激光装置光学元件薄膜材料的选取及辐照性能分析提供理论依据。 展开更多
关键词 X射线自由电子激光 金属钌薄膜 双温模型 数值分析
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广西高职“1+X”证书试点专业与产业适应性研究
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作者 孙晓宇 郭彩扣 阙勇平 《职业技术教育》 北大核心 2024年第8期46-51,共6页
职业院校专业设置与区域产业结构的适应性,直接关系到职业教育能否满足产业结构优化升级的需求。采用2019-2022年广西高职专业建设数据及“1+X”证书制度试点建设数据,量化分析“1+X”试点专业与产业结构适应性情况,结果显示:第一产业... 职业院校专业设置与区域产业结构的适应性,直接关系到职业教育能否满足产业结构优化升级的需求。采用2019-2022年广西高职专业建设数据及“1+X”证书制度试点建设数据,量化分析“1+X”试点专业与产业结构适应性情况,结果显示:第一产业对应的人才培养结构偏离度均为正值且数值远高于0.2的适应水平,“1+X”证书制度试点专业人才培养规模远远小于广西第一产业的需求;第二产业对应的广西高职人才试点专业结构偏离度均为正值,试点专业人才培养规模小于广西第二产业的需求;第三产业试点专业结构偏离度均为负值,高职试点专业人才培养规模超过了第三产业对人才的需求。据此提出提升试单专业与产业适应性的策略:统筹高职专业布局,主动匹配产业结构调整;借助“1+X”证书制度试点,重构高职专业体系;充分调研市场需求,适时调整专业建设方向。 展开更多
关键词 产业结构 “1+X”证书制度 专业建设 高职教育
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Interacting system NGC 7805/6(Arp 112)and its tidal dwarf galaxy candidate
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作者 Zhen-Xing Fu Chandreyee Sengupta +5 位作者 Ramya Sethuram Bikram Pradhan Mridweeka Singh Kuntal Misra TomCScott Yin-Zhe Ma 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第2期149-156,共8页
We present results from our Giant Metrewave Radio Telescope(GMRT)HⅠ,Himalayan Chandra Telescope(HCT)Hα,1 m Sampurnanand Telescope(ST)and 1.3 m Devasthal Fast Optical Telescope(DFOT)deep optical observations of the N... We present results from our Giant Metrewave Radio Telescope(GMRT)HⅠ,Himalayan Chandra Telescope(HCT)Hα,1 m Sampurnanand Telescope(ST)and 1.3 m Devasthal Fast Optical Telescope(DFOT)deep optical observations of the NGC 7805/6(Arp 112)system to test KUG 2359+311’s tidal dwarf galaxy(TDG)candidacy and explore the properties of the interacting system.Our GMRT HⅠmap shows no HⅠdetection associated with KUG 2359+311,nor any HⅠtail or bridge-like structure connecting KUG 2359+311 to the NGC 7805/6 system.Our HCT Hαimage,on the other hand,displays strong detections in KUG 2359+311,with net SFR0.035±0.009 M_(⊙)yr^(-1).The Hαdata constrain the redshift of KUG 2359+311 to 0.00≤z≤0.043,compared to the redshift of NGC 7806 of0.015.TDGs detected to date have all been HⅠrich,and displayed HⅠ,ionised gas and stellar tidal debris trails(bridges or tails)linking them to their parent systems.However,neither our HⅠdata nor our optical imaging,while three magnitudes deeper than SDSS,reveals a tidal trail connecting KUG 2359+311 to NGC 7805/6.Lack of HⅠ,presence of an old stellar population,ongoing star formation and reasonably high SFR compared to normal dwarf galaxies suggest that KUG 2359+311 may not be an Arp 112 TDG.It is most likely a case of a regular gas-rich dwarf galaxy undergoing a morphological transformation after having lost its entire gas content to an interaction with the Arp 112 system.Redshift and metallicity from future spectroscopic observations of KUG 2359+311 would help clarify the nature of this enigmatic structure. 展开更多
关键词 GALAXIES dwarf-galaxies interactions-galaxies spiral-galaxies star formation-galaxies peculiar-radio lines GALAXIES
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Simultaneous control of ferromagnetism and ferroelasticity by oxygen octahedral backbone stretching
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作者 Genhao Liang Hui Cao +6 位作者 Long Cheng Junkun Zha Mingrui Bao Fei Ye Hua Zhou Aidi Zhao Xiaofang Zhai 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期186-192,共7页
Coexistence of ferromagnetism and ferroelasticity in a single material is an intriguing phenomenon,but has been rarely found.Here we studied both the ferromagnetism and ferroelasticity in a group of LaCoO3 films with ... Coexistence of ferromagnetism and ferroelasticity in a single material is an intriguing phenomenon,but has been rarely found.Here we studied both the ferromagnetism and ferroelasticity in a group of LaCoO3 films with systematically tuned atomic structures.We found that all films exhibit ferroelastic domains with four-fold symmetry and the larger domain size(higher elasticity)is always accompanied by stronger ferromagnetism.We performed synchrotron x-ray diffraction studies to investigate the backbone structure of the CoO6 octahedra,and found that both the ferromagnetism and the elasticity are simultaneously enhanced when the in-plane Co–O–Co bond angles are straightened.Therefore the study demonstrates the inextricable correlation between the ferromagnetism and ferroelasticity mediated through the octahedral backbone structure,which may open up new possibilities to develop multifunctional materials. 展开更多
关键词 perovskite oxide film FERROMAGNETISM FERROELASTICITY twin domain
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Interfacial Electronic Modulation of Dual-Monodispersed Pt–Ni_(3)S_(2) as Efficacious Bi-Functional Electrocatalysts for Concurrent H_(2) Evolution and Methanol Selective Oxidation
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作者 Qianqian Zhao Bin Zhao +7 位作者 Xin Long Renfei Feng Mohsen Shakouri Alisa Paterson Qunfeng Xiao Yu Zhang Xian‑Zhu Fu Jing‑Li Luo 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第4期415-431,共17页
Constructing the efficacious and applicable bifunctional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction(OER) are critical to the develop... Constructing the efficacious and applicable bifunctional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction(OER) are critical to the development of electrochemicallydriven technologies for efficient hydrogen production and avoid CO_(2) emission. Herein, the hetero-nanocrystals between monodispersed Pt(~ 2 nm) and Ni_(3)S_(2)(~ 9.6 nm) are constructed as active electrocatalysts through interfacial electronic modulation, which exhibit superior bi-functional activities for methanol selective oxidation and H_(2) generation. The experimental and theoretical studies reveal that the asymmetrical charge distribution at Pt–Ni_(3)S_(2) could be modulated by the electronic interaction at the interface of dual-monodispersed heterojunctions, which thus promote the adsorption/desorption of the chemical intermediates at the interface. As a result, the selective conversion from CH_(3)OH to formate is accomplished at very low potentials(1.45 V) to attain 100 m A cm^(-2) with high electronic utilization rate(~ 98%) and without CO_(2) emission. Meanwhile, the Pt–Ni_(3)S_(2) can simultaneously exhibit a broad potential window with outstanding stability and large current densities for hydrogen evolution reaction(HER) at the cathode. Further, the excellent bi-functional performance is also indicated in the coupled methanol oxidation reaction(MOR)//HER reactor by only requiring a cell voltage of 1.60 V to achieve a current density of 50 m A cm^(-2) with good reusability. 展开更多
关键词 Dual-monodispersed heterostructure Electronic interactive modulation Reaction mechanism Methanol oxidation reaction Hydrogen generation
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Electrochemical Activation-Induced Structural Transformation in Ni(OH)_(2)/Ti_(3)C_(2)T_(x)/NF Systems with Enhanced Electrochemical Performance for Hybrid Supercapacitors
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作者 Chuming Xu Lu Dai +6 位作者 Yiming Zhao Shuang Li Yapan Wu Xueqian Wu Gaixia Zhang Shuhui Sun Dongsheng Li 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第4期277-284,共8页
Exploring a novel strategy for large-scale production of battery-type Ni(OH)_(2)-based composites,with excellent capacitive performance,is still greatly challenging.Herein,we developed a facile and cost-effective stra... Exploring a novel strategy for large-scale production of battery-type Ni(OH)_(2)-based composites,with excellent capacitive performance,is still greatly challenging.Herein,we developed a facile and cost-effective strategy to in situ grow a layer of Ni(OH)_(2)/Ti_(3)C_(2)T_(x)composite on the nickel foam(NF)collector,where Ti_(3)C_(2)T_(x)is not only a conductive component,but also a catalyst that accelerates the oxidation of NF to Ni(OH)_(2).Detailed analysis reveals that the crystallinity,morphology,and electronic structure of the integrated electrode can be tuned via the electrochemical activation,which is beneficial for improving electrical conductivity and redox activity.As expected,the integrated electrode shows a specific capacity of 1.09 C cm^(-2)at 1 mA cm^(-2)after three custom activation cycles and maintains 92.4%of the initial capacity after 1500 cycles.Moreover,a hybrid supercapacitor composed of Ni(OH)_(2)/Ti_(3)C_(2)T_(x)/NF cathode and activated carbon anode provides an energy density of 0.1 mWh cm^(-2)at a power density of 0.97 mW cm^(-2),and excellent cycling stability with about 110%capacity retention rate after 5000 cycles.This work would afford an economical and convenient method to steer commercial Ni foam into advanced Ni(OH)_(2)-based composite materials as binder-free electrodes for hybrid supercapacitors. 展开更多
关键词 electrochemical activation hybrid supercapacitors Ni(OH)_(2) Ti_(3)C_(2)T_(x)
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Highly Thermally Conductive and Structurally Ultra‑Stable Graphitic Films with Seamless Heterointerfaces for Extreme Thermal Management
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作者 Peijuan Zhang Yuanyuan Hao +17 位作者 Hang Shi Jiahao Lu Yingjun Liu Xin Ming Ya Wang Wenzhang Fang Yuxing Xia Yance Chen Peng Li Ziqiu Wang Qingyun Su Weidong Lv Ji Zhou Ying Zhang Haiwen Lai Weiwei Gao Zhen Xu Chao Gao 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期383-397,共15页
Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme altern... Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics. 展开更多
关键词 Highly thermally conductive Structurally ultra-stable Graphitic film Extreme thermal management Liquid nitrogen bubbling
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单晶X射线衍射技术的进展评述 被引量:4
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作者 王哲明 严纯华 《现代仪器》 2001年第6期1-8,共8页
本文评述了十余年来单晶X射线衍射技术的进展。介绍高亮度X射线光源的获得,能够大幅度提高衍射数据收集速度和灵敏度的二维电子面探测器成像板IP和电荷耦合器件CCD的工作原理和应用等,并通过实例说明这些技术上的重大进步正在极大地推... 本文评述了十余年来单晶X射线衍射技术的进展。介绍高亮度X射线光源的获得,能够大幅度提高衍射数据收集速度和灵敏度的二维电子面探测器成像板IP和电荷耦合器件CCD的工作原理和应用等,并通过实例说明这些技术上的重大进步正在极大地推动人们对物质微观结构的深入认识并带来巨大的成果。 展开更多
关键词 单晶X射线衍射 高亮度X射线光源 面探测器 成像板 电荷耦合器件 晶体结构
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同步辐射X射线能量色散法与新矿物--罗布莎矿的测试
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作者 戎合 杨经绥 +4 位作者 MAO HoKwang SHU JingFu HU JingZhu 白文吉 方青松 《岩石学报》 SCIE CAS CSCD 北大核心 2008年第7期1605-1612,共8页
同步辐射 X 射线能量色散法以其高能量微射束,对微小矿物和包裹体的晶体结构分析有着独特优势。以在 BNL-NSLS-X17C 对新矿物罗布莎矿的测试为例,阐述其基本原理特点及其方法。
关键词 罗布莎矿 X射线能量色散法 美国BNL—NSLS—X17C射束线
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Continuous Fabrication of Ti_(3)C_(2)T_x MXene-Based Braided Coaxial Zinc-Ion Hybrid Supercapacitors with Improved Performance 被引量:4
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作者 Bao Shi La Li +3 位作者 Aibing Chen Tien-Chien Jen Xinying Liu Guozhen Shen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第2期206-215,共10页
Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimiz... Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti_(3)C_(2)T_x MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti_(3)C_(2)T_x MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm^(-2),the energy density of 42.8μWh cm^(-2)at 5 mV s^(-1),and excellent cycling stability with 83.58%capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days. 展开更多
关键词 Ti_(3)C_(2)T_x MXene Fiber supercapacitor Coaxial structure Zinc-ion
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Atomically Dispersed Transition Metal-Nitrogen-Carbon Bifunctional Oxygen Electrocatalysts for Zinc-Air Batteries:Recent Advances and Future Perspectives 被引量:6
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作者 Fang Dong Mingjie Wu +4 位作者 Zhangsen Chen Xianhu Liu Gaixia Zhang Jinli Qiao Shuhui Sun 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第2期257-281,共25页
Rechargeable zinc-air batteries(ZABs)are currently receiving extensive attention because of their extremely high theoretical specific energy density,low manufacturing costs,and environmental friendliness.Exploring bif... Rechargeable zinc-air batteries(ZABs)are currently receiving extensive attention because of their extremely high theoretical specific energy density,low manufacturing costs,and environmental friendliness.Exploring bifunctional catalysts with high activity and stability to overcome sluggish kinetics of oxygen reduction reaction and oxygen evolution reaction is critical for the development of rechargeable ZABs.Atomically dispersed metal-nitrogen-carbon(M-N-C)catalysts possessing prominent advantages of high metal atom utilization and electrocatalytic activity are promising candidates to promote oxygen electrocatalysis.In this work,general principles for designing atomically dispersed M-N-C are reviewed.Then,strategies aiming at enhancing the bifunctional catalytic activity and stability are presented.Finally,the challenges and perspectives of M-N-C bifunctional oxygen catalysts for ZABs are outlined.It is expected that this review will provide insights into the targeted optimization of atomically dispersed M-N-C catalysts in rechargeable ZABs. 展开更多
关键词 Atomically dispersed metal-nitrogen-carbon Oxygen evolution reaction(OER) Oxygen reduction reaction(ORR) Bifunctional oxygen electrocatalysts Zinc-air batteries(ZABs)
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Cotton pads-derived carbon materials/reduced graphene oxide modified with polypyrrole for electrode of supercapacitors 被引量:1
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作者 Ofelia MArias-Pinedo Elvis OLopez +5 位作者 Ivonne EMonje RSoria-Martinez Antony Bazan-Aguilar Clemente Alfredo Luyo Caycho Gabriel Angel Planes Angelica Maria Baena-Moncada 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期41-53,共13页
This study investigates the influence of electropolymerization conditions on the deposition of polypyrrole(PPy)onto cotton-derived carbon fiber(CF)modified with reduced graphene oxide(rGO)for supercapacitors applicati... This study investigates the influence of electropolymerization conditions on the deposition of polypyrrole(PPy)onto cotton-derived carbon fiber(CF)modified with reduced graphene oxide(rGO)for supercapacitors applications using an experimental/theorical approach.The surface modification of CF by rGO and/or by PPy electrodeposited at 10,25 and 50 mV s^(-1) was thoroughly examined physicochemical and electrochemically.Composite electrodes comprising CF-rGo-PPy,synthesized via electropolymerization at 25 mV s^(-1),demonstrated a remarkable increase in capacitance,showcasing~742 F g^(-1) compared to 153 F g^(-1) for CF.SEM,N_(2)-surface area,XPS,and TD-DFT approach revealed that the higher capacitance observed in CF-rGo-PPy electrodes underscores the influence of morphology and charged nitrogen species on the electrochemical performance of these modified electrodes.Notably,this electrode material achieves a specific capacitance retention of~96%of their initial capacitance after 10000 cycles at 0.5 A g^(-1) measured in a two-electrodes cell configuration.This work also discusses the influence of the scan rate used for pyrrole electropolymerization on the pseudocapacitance contribution of PPy and its possible effect on the porosity of the material.These results highlight the importance of appropriate electropolymerization conditions that allow obtaining the synergistic effect between CF,rGO and PPy. 展开更多
关键词 SUPERCAPACITORS Cotton pads-derived carbon fibers rGO PPy TD-DFT
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西藏罗布莎铬铁矿床中的金刚石包体X更线衍射研究 被引量:5
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作者 施倪承 白文吉 +5 位作者 马喆生 方青松 熊明 颜秉刚 代明泉 杨经绥 《地质学报》 EI CAS CSCD 北大核心 2002年第4期496-500,T004,共6页
在西藏罗布莎蛇绿岩的豆荚状铬铁矿石及橄榄岩中找到了金刚石,少数金刚石存在有硅酸盐包体。本研究采用X射线衍射中的CCD(电子藕合)探测技术,测得了粒度仅为20 μm左右的包体矿物的粉晶X衍射数据,数据表明该硅酸盐包体有两种,为滑石和... 在西藏罗布莎蛇绿岩的豆荚状铬铁矿石及橄榄岩中找到了金刚石,少数金刚石存在有硅酸盐包体。本研究采用X射线衍射中的CCD(电子藕合)探测技术,测得了粒度仅为20 μm左右的包体矿物的粉晶X衍射数据,数据表明该硅酸盐包体有两种,为滑石和蛇纹石。从而说明了西藏罗布莎产于蛇绿岩中的金刚石是天然金刚石,并非“人工合成物”。 展开更多
关键词 铁铬矿床 X射线衍射 西藏 蛇绿岩 金刚石包体 电子藕合探测技术
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先天性小肠狭窄及肠闭锁的X线检查与诊断 被引量:7
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作者 李春卫 王道才 +1 位作者 刘凯 许玉军 《医学影像学杂志》 2012年第11期1881-1883,共3页
目的探讨先天性小肠狭窄及肠闭锁X线检查与诊断价值。方法回顾性分析15例经手术证实的先天性小肠狭窄及肠闭锁病例,15例均行立位腹部平片检查,其中6例行口服医用硫酸钡检查,9例行口服非离子型含碘对比剂检查。结果立位腹部平片显示12例... 目的探讨先天性小肠狭窄及肠闭锁X线检查与诊断价值。方法回顾性分析15例经手术证实的先天性小肠狭窄及肠闭锁病例,15例均行立位腹部平片检查,其中6例行口服医用硫酸钡检查,9例行口服非离子型含碘对比剂检查。结果立位腹部平片显示12例高位肠梗阻,3例低位肠梗阻,造影检查显示十二指肠闭锁2例,空肠狭窄7例,空肠闭锁3例,回肠闭锁3例。结论 X线检查先天性小肠狭窄及肠闭锁具有重要价值。 展开更多
关键词 肠狭窄 肠闭锁 X线检查与诊断
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Book review “Wattles: Australian Acacia species around the world” by David M. Richardson, Johannes J. Le Roux and Elizabete Marchante
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作者 Klaus von Gadow 《Forest Ecosystems》 SCIE CSCD 2024年第2期140-141,共2页
In a world of Google and AI, developing an encyclopedic coverage of a theme that is of great interest to biologists, social scientists, politicians and environmental managers, is a daunting challenge. Wattles is a boo... In a world of Google and AI, developing an encyclopedic coverage of a theme that is of great interest to biologists, social scientists, politicians and environmental managers, is a daunting challenge. Wattles is a book that presents new knowledge, makes interesting reading, and has the potential to stimulate research in a variety of disciplines. We learn that Acacia, commonly known as the wattles or acacias, is a genus of shrubs and trees comprising 1,083 species of which 417 are known to have been introduced to areas outside their native range. We are surprised to read that Australian acacias are found almost everywhere, in virtually all terrestrial habitats, including woodlands, grasslands, alpine settings,rainforests, coastal dunes and deserts, causing major environmental and socio-economic changes in the invaded regions. Until recently, Acacia comprised a group of plant species native to Africa, South America and Australasia, but the name is now reserved for species predominantly from Australia, including some from Southeast Asia. The genus name Acacia is Neo-Latin, and refers to a preparation extracted from the leaves and fruit pods of Vachellia nilotica, the original type of the genus. 展开更多
关键词 RICHARDSON OUTSIDE LATIN
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上海地区101名正常合人群X线头影测量McNamara分析 被引量:22
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作者 潘晓岗 刘泓虎 曹惠菊 《上海口腔医学》 CAS CSCD 1996年第4期195-197,共3页
作者对上海地区101名正常 恒牙 初期儿童及恒牙 期成人应用McNamara分析法进行X线头影测量分析。结果显示:上海地区恒牙 初期儿童及恒牙 期成人的颅颌线距的正常值范围,正常颅颌线距特征。
关键词 X线头影测量 MCNAMARA分析法 正常
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为培养创新人才构筑X射线衍射仪优质资源共享服务平台 被引量:4
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作者 苗伟 刘兴涛 陶琨 《实验技术与管理》 CAS 2007年第6期12-15,共4页
X射线衍射实验室在原有开放的基础上进一步地开放服务,充分发挥X射线衍射仪等优质资源的作用,扩大了开放范围,增加了仪器并开发其功能,延长了开放时间。实验室的开放提高了学生的动手能力、观察能力以及分析问题和解决问题的能力,... X射线衍射实验室在原有开放的基础上进一步地开放服务,充分发挥X射线衍射仪等优质资源的作用,扩大了开放范围,增加了仪器并开发其功能,延长了开放时间。实验室的开放提高了学生的动手能力、观察能力以及分析问题和解决问题的能力,为培养学生的创新能力提供了一个服务平台,为培养高素质创新人才做出了一定的贡献。 展开更多
关键词 实验室开放 X射线衍射仪 优质资源 创新人才培养 服务平台
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基于层次分析法的试点院校X证书工作评价体系研究 被引量:5
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作者 王伟伟 蒋世军 曾升科 《中国职业技术教育》 北大核心 2021年第7期72-76,共5页
结合相关文件要求和X证书试点工作实际,运用关键绩效指标(KPI),从工作机制、师资培养、人才培养、经费保障、目标等方面设计5个维度的19个评价指标,并明确了评分标准;以德尔菲法和层次分析法(AHP)为理论基础设计各层次指标的权重,构建... 结合相关文件要求和X证书试点工作实际,运用关键绩效指标(KPI),从工作机制、师资培养、人才培养、经费保障、目标等方面设计5个维度的19个评价指标,并明确了评分标准;以德尔菲法和层次分析法(AHP)为理论基础设计各层次指标的权重,构建试点院校X证书工作评价指标体系,并建立试点院校X证书工作评价分值的计算公式。通过出台绩效评价文件、将评价结果运用于校领导班子考核及建立X证书工作定期抽查监测制度等措施,将有利于保障该评价指标体系有效运转,更好地推动各试点院校开展1+X证书制度试点工作。 展开更多
关键词 KPI AHP X证书 工作评价
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