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High population and dispersion of pentacoordinated Al~Ⅴ species on the surface of ?ame-made amorphous silica-alumina

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Science Bulletin 2019年第8期64卷 516-523页

作者： Zichun Wang Yijiao Jiang Xianfeng Yi cuifeng zhou Aditya Rawal James Hook Zongwen Liu Feng Deng Anmin Zheng Michael Hunger Alfons Baiker Jun Huang School of Chemical and Biomolecular Engineering & Sydney Nano Institute The University of Sydney Department of Engineering Macquarie University State Key Laboratory Magnetic Resonance & Atomic Molecular Physics Wuhan Institute of Physics & Mathematics Chinese Academy of Sciences Mark Wainwright Analytical Centre University of New South Wales Institute of Chemical Technology University of Stuttgart Department of Chemistry and Applied Bioscience ETH Zürich

Pentacoordinated Al(Al~Ⅴ)species in silica-alumina are promising to promote the formation of acid sites or act as surface defects for tailoring single-atom ***,pentahedral coordination(Al~Ⅴ)is rarely observed in conventionally prepared ***,we show that high population and dispersion of Al~Ⅴ species on the surface of amorphous silica-alumina(ASA)can be achieved by means of flame spray *** resolution TEM/EDX,high magnetic-field NMR and DFT calculations are employed to characterize the structure of as-prepared ***-state ^(27)Al multi-quantum MAS NMR experiments show that most of the Al~Ⅴspecies are formed independently from the alumina phase and are accessible for guest molecules on the *** water adsorption,these Al~Ⅴ species are transformed to Al~Ⅵ species,structurally similar to surface Al~Ⅳ species,as confirmed by DFT *** outstanding catalytic activity of as-synthesized ASA is demonstrated using the in situ H/D exchange reaction with deuterated benzene as an *** Al~Ⅴ-rich ASA provides a much lower activation energy(～30 kJ/mol)than that reported for zeolite H-ZSM-5(～60 kJ/mol).The superior catalytic performance is attributed to the high Al~Ⅴcontent promoting the surface active sites in *** knowledge gained on the synthesis of Al~Ⅴ-rich ASAs and the nature of aluminum coordination in these materials could pave the way to more efficient silica-alumina based catalysts.

关键词： Amorphous silica-alumina Pentacoordinated Al~Ⅴ species 27Al multiple quantum magic-angle-spinning NMR H/D exchange

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英语家庭教育现状与对策刍探

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成才之路 2020年第8期 138-139页

作者：周翠凤江苏省苏州市相城区御窑小学江苏苏州215100

英语家庭教育是一种启蒙教育,对学生的英语学习具有重要影响。目前,英语家庭教育还存在城市与农村差异较大、教育方式单一、功利性较强、教学手段不当等问题。要提高英语家庭教育效果,家长就要树立正确的英语教育理念,提升知识水平和教... 详细信息

英语家庭教育是一种启蒙教育,对学生的英语学习具有重要影响。目前,英语家庭教育还存在城市与农村差异较大、教育方式单一、功利性较强、教学手段不当等问题。要提高英语家庭教育效果,家长就要树立正确的英语教育理念,提升知识水平和教育教学技能,为学生提供适合的英语学习环境和条件。

关键词：英语教学家庭教育教学方式教育理念教育技能教学效果

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语境教学法在小学低段英语对话教学中的应用浅析

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英语教师 2020年第2期20卷 69-71页

作者：周翠凤江苏省苏州市相城区御窑小学

介绍语境教学法的相关概念。阐述在小学低段英语对话教学中运用语境教学法的必要性。结合教学实例,从生词处理、对话理解和对话练习、对话拓展三个阶段探究语境教学法在小学低段英语对话教学中的具体应用。认为语境教学法能有效激发学... 详细信息

介绍语境教学法的相关概念。阐述在小学低段英语对话教学中运用语境教学法的必要性。结合教学实例,从生词处理、对话理解和对话练习、对话拓展三个阶段探究语境教学法在小学低段英语对话教学中的具体应用。认为语境教学法能有效激发学生的学习兴趣,提高学生的学习效率。

关键词：语境教学法小学低段英语对话教学

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Recent development in electrode design for wide-temperature supercapacitors

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Science China Chemistry 2025年第1期68卷 96-117页

作者： Jianhong Liu Qiang zhou Yuxiao Lin Xinsheng Zhao Guangmin zhou Xiaoxiao Li School of Physics and Electronic Engineering Jiangsu Normal University Tsinghua-Berkeley Shenzhen Institute & Tsinghua Shenzhen International Graduate School Tsinghua University

An ever-increasing market demand has stimulated the soaring enthusiasm of researchers to develop wide-temperature supercapacitors(SCs). The active electrode is one of the most important parts of SC, which is directly related to the energy density,power transmission and long-term cyclability of the device in the wide-temperature environment. Compared with the SC electrodes aimed for room-temperature application, the SC electrodes for operating at wide-temperature scene often face greater challenges. In this review, the main challenges of SC electrodes under various temperature conditions, including low, high and cross-fade temperatures, are summarized. The relevant performance decay and failure mechanisms of wide-temperature SC electrodes are analyzed. In addition, this review deals with the recent studies and developments in robust wide-temperature SC electrodes with respect to the rational design of electrode structures and the exploitation of advanced active materials. Finally, the future directions for exploring reliable wide-temperature SCs are also proposed.

关键词： supercapacitor wide-temperature electrode design active materials

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Dative B–N bonds weaven toward two-dimensional purely organic materials for single crystals

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Science China Chemistry 2025年第1期68卷 12-14页

作者： Wei-Lei zhou Siwei Wang Yong Chen College of Chemistry and Materials Science Inner Mongolia Key Laboratory of Chemistry for Nature Products and Synthesis for Functional Molecules Innovation Team of Optical Functional Molecular Devices Inner Mongolia Minzu University College of Chemistry Nankai University

Molecular topology is one of the important topics to study and understand the relationship between molecular structure and properties [1]. Particularly, two-dimensional (2D) materials with extremely high surface area and ultra-thin morphology have attracted considerable attention due to their unexpected properties in materials and chemistry [2,3].

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Fine-tuning the spatial allocation of phytohormones for smart canopy, smart breeding, and smart agriculture

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Science China Life Sciences 2025年第1期68卷 309-310页

作者： Tao zhou Lin Li National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural University HuBei HongShan Laboratory

The dual challenges of global climate change and population growth have increased demand for higher crop yields per unit area. The innovative technology of smart agriculture aims to synergize breeding, cultivation, and production through the application of biological and informatics technologies. Historically, the “Green Revolution” introduced semidwarf varieties of certain key crops by utilizing mutations affecting gibberellin pathways, which significantly increased planting densities and yields.

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Microstructure and Wear/corrosion Resistance of Stainless Steel Laser-alloyed with Mn+W_(2)C, Mn+NiWC and Mn+SiC

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 283-294页

作者： zhou Rui DIAO Xiaogang SUN Yixin School of Metallurgical Engineering Jiangsu University of Science and TechnologyZhangjiagang 215600China CITIC Heavy Cast Iron Industry Co. Ltd.Luoyang 417039China

In-situ formed high Mn steel coating reinforced by carbides was formed by laser surface alloying(LSA).Laser alloyed layers on 1Cr18Ni9Ti steel with Mn+W_(2)C(specimen A),Mn+NiWC(specimen B)and Mn+SiC(specimen C)powders were fabricated to improve the wear and corrosion behavior of 1Cr18Ni9Ti steel blades in high speed *** evolution,phases,element distribution,microhardness,wear and corrosion behavior of the laser alloyed layers were *** indicated that high Mn steel matrix composites with undissolved W_(2)C,WC and other in-situ formed carbides were formed by LSA with Mn+W_(2)C and Mn+NiWC while SiC totally dissolved into the high Mn matrix when adding Mn+*** as the binding phase in Ni-WC powder decreased the crack sensitivity of the alloyed layer as compared with the addition of W_(2)C *** improvement in average microhardness was achieved in the matrix in specimen A,B and C,with the value of 615,602 and 277 HV_(0.5),while that of the substrate was 212 HV_(0.5).The increase of microhardness,wear and corrosion resistance is highly corelated to microstructure,formed phases,type and content of carbides,micro-hardness and toughness of the alloyed layers.

关键词： laser surface alloying stainless steel carbide type microstructure wear and corrosion resistance

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Distributed fiber optic sensing system for vibration monitoring of 3D printed bridges

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Optoelectronics Letters 2025年第1期21卷 28-34页

作者： ZHAO Shuai zhou Ran LUO Mingming LIU Jianfei LIU Xiongfei zhou Tao School of Electronic Information Engineering Hebei University of Technology Tianjin Key Laboratory of Electronic Materials and Devices School of Civil Engineering and Transportation Hebei University of Technology Tianjin Jinhang Institute of Technical Physics

The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities, including design, construction, and maintenance of bridges, tunnels, ports and other infrastructures. In this paper, a distributed vibration sensing system is proved to be responsive to a single touch over a 1.8-m-long equivalent fiber segment, covering a vibration frequency from 5 Hz to 25 kHz. The sensing fiber was arranged as an S type layout on the bridge to recognize the standing state, windblown disturbance, and walking vibration. Moreover, the knocking and climbing events are recognized fiber laying spinning lines and hanging on the fences, respectively. The demonstration shows an accurate positioning and sensitive vibration monitoring applied on the automated three-dimensional(3D) printed bridge, which is applicable to all kinds of 3D printed facilities as intelligent sensory neuro-networks.

关键词： Spinning (fibers)

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Controlled cationic ring-opening polymerization of L-lactide by organic ion pair: novel approach to isotactic-rich and crystalline polylactide

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Science China Chemistry 2025年第1期68卷 394-402页

作者： Zhiqiang Ding Mingqian Wang Zijing zhou Bin Wang Yuesheng Li Tianjin Key Laboratory of Composite & Functional Materials School of Materials Science and Engineering Tianjin University

Living/controlled cationic ring-opening polymerization （ROP） of L-lactide is a promising approach to isotactic-rich and crystalline poly（L-lactide）.In contrast with the unsubstituted lactones,L-LA can not be polymerized by organic Lewis acids or carbenium ions,and the state of the art in this field is the cationic ROP of L-LA catalyzed by Br?nsted acid/alcohol system via activated monomer ***,we reported the first example of controlled cationic ROP of L-LA by using Meerweintype ion pair[Me3O]+[B（C6F5）4]-as the catalyst.[Me3O]+[B（C6F5）4]-promoted rapid L-LA cationic polymerization in the absence of alcohol,producing isotactic-rich and crystalline PLLA without transesterification and epimerization side *** activated chain end mechanism,involving twice SN2 substitution and configuration-inversion （S→R→S） with the assistance of released Me2O,was proposed and further verified by density functional theory and control *** work expands the catalytic toolbox of isotactic-rich and crystalline polylactide *** represents a unique example of cationic-controlled polymerization of L-LA catalyzed by an organic ion pair.

关键词： organic ion pair controlled cationic ring-opening polymerization activated chain end mechanism isotactic-rich polylactide

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Gradient maturation experiment on hairs implies taphonomic changes in fossil hairs

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Science China Earth Sciences 2025年第1期68卷 62-73页

作者： Xin LI Yibo zhou Tao ZHAO Xingjian HE Yanhong PAN State Key Laboratory for Mineral Deposits Research Center for Critical Earth Material Cycling Centre for Research and Education on Biological Evolution and Environment and Frontiers Science School of Earth Sciences and Engineering Nanjing University Institute of Palaeontology Yunnan Key Laboratory of Earth System Science Yunnan Key Laboratory for PalaeobiologyYunnan University

Mammalian hair, as a key feature related to endothermy, physical protection, and camouflage, has a long geohistorical record that dates back even to the Mesozoic. However, the limited information on the taphonomy of hair hinders the understanding of its evolutionary significance in deep time. To address this, we conducted taphonomic experiments to simulate the transformation process of black hair. The changes in the morphological structure, microscopic characteristics, and chemical composition of hair during the simulated fossilization process were documented by scanning electron microscopy, Fourier transform infrared(FTIR) spectroscopy, and Raman spectroscopy. Our results revealed that damage to the morphology of hair began at a mild temperature(150–175°C), and hair transformed into a fluid-like mass at a relatively high temperature(200°C). In addition, the morphological structure of melanosomes had relatively greater preservation potential than keratins did, and the microscopic features of melanosomes were persistently stable. The Raman and FTIR spectra indicated that the characteristic melanin and keratin peaks changed as the temperature increased. Although the chemical signals were not lost completely, the variations in the characteristic amide bands in the FTIR spectra indicate that the keratins severely degraded at high temperatures(>200°C), whereas the characteristic melanin bands in the Raman spectra suggested that melanin signals were still recognizable, even at high temperatures(>200°C). These results were confirmed by principal component analysis(PCA) and principal component analysis linear discriminant analysis(PCA–LDA). In addition, the Raman signals of all the samples in the simulated experiments were distinguished from the signals of common geological carbonaceous materials(humic acid), which suggested that Raman spectroscopy can be used to detect melanin in fossils.

关键词： Mammalian hair Melanin Keratin Fossilization Experimental taphonomy

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