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Electrochemical Scanning Tunneling Microscopy──An Ex－situ Study of the Growth of Polypyrrole Films on Electrodes

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Chemical Research in Chinese Universities 1994年第2期10卷 72-78页

作者： li Jing and wang er-kang (Laboratory of Electroanalytical Chemistiy, Changchun Institute of Applied Chemistr, Chinese Acadeniy of Sciences, Changchun, 130022 )

his paper covers the electropolymerized polypyrrole doped with p-toluenesul-fonate studied using scanning tunneling microscope. The growth processes of polypyrrole films on the electrode surface were observed. Polypyrrole chain struc-ture with many separated micro-holes of 0. 15 nm diameter at the initial state ofelectropolymerization can be seen from obtained STM images. This structure is ex-tremely similar to the pioneer-proposed ideal structure of polypyrrole chains. Thereexisted some helical structure and simple strands on the electrode surface, which isdue to different existing states of polypyrrole chains on electrode surface. STM ex-periments showed that polypyrrole chains were firstly formed on the electrode sur-face, then, they growed gradually by 3-dimensional mode during slow oxidation toform many separated micro-islands. Finally, a large corrugation area of polymerfilms occurred on the electrodes.

关键词： Electrochemical scanning tunneling microscopy Polypyrrole films,Electrochemistry

Role of micro-Ca/In alloying in tailoring the microstructural characteristics and discharge performance of dilute Mg-Bi-Sn-based alloys as anodes for Mg-air batteries

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Journal of Magnesium and Alloys 2024年第1期12卷 251-266页

作者： Fei-er Shangguan Wei-li Cheng Yu-hang Chen Ze-qin Cui Hui Yu Hong-xia wang li-fei wang Hang li Hua Hou School of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Materials Science and Engineering Hebei University of TechnologyTianjin 300132China School of Materials Science and Engineering North University of ChinaTaiyuan 030051China

The influence of micro-Ca/In alloying on the microstructural charac teristics,electrochemical behaviors and discharge properties of extruded dilute Mg-0.5Bi-0.5Sn-based(wt.%)alloys as anodes for Mg-air batteries are *** grain size and texture intensity of the Mg-Bi-Sn-based alloys are significantly decreased after the Ca/In alloying,particularly for the In-containing *** that,in addition to nanoscale Mg_(3)Bi_(2)phase,a new microscale Mg_(2)Bi_(2)Ca phase forms in the Ca-containing *** electrochemical test results demonstrate that Ca/In micro-alloying can enhance the electrochemical *** In to alloy the Mg-Bi-Sn-based alloy is effective in restricting the cathodic hydrogen evolution(CHE)kinetics,leading to a low self-corrosion rate,while severe CHE occurred after Ca *** micro-alloying of Ca/In to Mg-Bi-Sn-based alloy strongly deteriorates the compactness of discharge products film and mitigates the"chunk effect"(CE),hence the cell voltage,anodic efficiency as well as discharge capacity are greatly *** In-containing alloy exhibits outstanding discharge performance under the combined effect of the modified microstructure and discharge products,thus making it a potential anode material for primary Mg-air battery.

关键词： Mg-air batteries Mg-Bi-Sn based alloys Electrochemical behaviors Discharge properties

Comparison of engineering failures and seismic responses of 500 kV transformer-bushing systems in the 2022 Luding earthquake

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Earthquake Engineering and Engineering Vibration 2024年第4期23卷 1029-1041页

作者： Zhu wang Wu Ming’er Xie Qiang Department of Structural Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures(Tongji University) Shanghai 200092China

Cemented and mechanically clamped types of end fittings(fitting-C and fitting-M)are commonly used in transformer *** the Luding Ms 6.8 earthquake that occurred in China on September 5,2022,all transformer bushings with the two types of end fittings in a 500 kV substation were ***-earthquake field investigations were conducted,and the failures of the two types of bushings were *** elementary simulation models of the transformer-bushing systems were developed to simulate the engineering failures,and further compute their seismic responses for *** results indicate that the hitch lugs of the connection flange are structurally harmful to seismic ***-M can decrease the bending stiffness of the bushing due to the flexible sealing rubber *** it provides a more flexible connection that dissipates energy,the peak accelerations and relative displacements at the top of the bushing are significantly lower than those of the bushing with *** with fitting-C,fitting-M transfers the high-stress areas from the connection flange to the root of the porcelain,so the latter becomes the most vulnerable ***-M increases the failure risk of the low-strength porcelain,indicating the unsuitability of applying it in high-intensity fortification regions.

关键词： transformer bushing end fitting Luding earthquake,engineering failure seismic responses

Health diagnosis of ultrahigh arch dam performance using heterogeneous spatial panel vector model

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Water Science and Engineering 2024年第2期17卷 177-186页

作者： er-feng Zhao Xin li Chong-shi Gu The National Key Laboratory of Water Disaster Prevention Hohai UniversityNanjing 210098China NationalEngineering Research Centerof Water Resources Eficient Utilization and Engineering Safety Hohai UniversityNanjing 20098China

Currently,more than ten ultrahigh arch dams have been constructed or are being constructed in *** control is essential to long-term operation of these *** study employed the flexibility coefficient and plastic complementary energy norm to assess the structural safety of arch dams.A comprehensive analysis was conducted,focusing on differences among conventional methods in characterizing the structural behavior of the Xiaowan arch dam in ***,the spatiotemporal characteristics of the measured performance of the Xiaowan dam were explored,including periodicity,convergence,and time-effect *** findings revealed the governing mechanism of main ***,a heterogeneous spatial panel vector model was developed,considering both common factors and specific factors affecting the safety and performance of arch *** model aims to comprehensively illustrate spatial heterogeneity between the entire structure and local regions,introducing a specific effect quantity to characterize local deformation ***,the proposed model was applied to the Xiaowan arch dam,accurately quantifying the spatiotemporal heterogeneity of dam ***,the spatiotemporal distri-bution characteristics of environmental load effects on different parts of the dam were reasonably *** of the model prediction enhances its credibility,leading to the formulation of health diagnosis criteria for future long-term operation of the Xiaowan *** findings not only enhance the predictive ability and timely control of ultrahigh arch dams'performance but also provide a crucial basis for assessing the effectiveness of engineering treatment measures.

关键词： Ultrahigh arch dam Structural performance Deformation behavior Diagnosis criterion Panel data model

Prospects of the Multi-channel Photometric Survey Telescope in the Cosmological Application of Type Ia Supernovae

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Research in Astronomy and Astrophysics 2024年第4期24卷 183-191页

作者： Zhenyu wang Jujia Zhang Xinzhong er Jinming Bai Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China International Centre of Supernovae Yunnan Key LaboratoryKunming 650216China South-Western Institute for Astronomy Research Yunnan UniversityKunming 650500China

The Multi-channel Photometric Survey Telescope(Mephisto)is a real-time,three-color photometric system designed to capture the color evolution of stars and transients *** telescope system can be crucial in cosmological distance measurements of low-redshift(low-z,z■0.1)Type Ia supernovae(SNe Ia).To optimize the capabilities of this instrument,we perform a comprehensive simulation study before its official operation is scheduled to *** considering the impact of atmospheric extinction,weather conditions,and the lunar phase at the observing site involving the instrumental features,we simulate light curves of SNe Ia obtained by *** best strategy in the case of SN Ia cosmology is to take the image at an exposure time of 130 s with a cadence of 3 *** this condition,Mephisto can obtain hundreds of high-quality SNe Ia to achieve a distance measurement better than 4.5%.Given the on-time spectral classification and monitoring of the lijiang 2.4 m Telescope at the same observatory,Mephisto,in the whole operation,can significantly enrich the well-calibrated sample of supernovae at low-z and improve the calibration accuracy of high-z SNe Ia.

关键词： (stars:)supernovae:general (cosmology:)cosmological parameters telescopes

Nitrite-catalyzed economic and sustainable bromocyclization of tryptamines/tryptophols to access hexahydropyrrolo[2,3-b]indoles/tetrahydrofuroindolines in batch and flow

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Chinese Chemical Letters 2024年第7期35卷 247-252页

作者： Xiao Xiao Biao Chen Jia-Wei li Jun-Bo Zheng Xu wang Hang Zhao Fen-er Chen Institute of Pharmaceutical Science and Technology Collaborative Innovation Center of Yangtze River Delta Region Green PharmaceuticalsZhejiang University of TechnologyHangzhou 310014China College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China Engineering Center of Catalysis and Synthesis for Chiral Molecules Department of ChemistryFudan UniversityShanghai 200433China Shanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs Shanghai 200433China

A highly efficient and concise bromocyclization has been successfully achieved,in which tryptamine/tryptophol derivates can be transformed to valuable HPI/TFI scaffolds with economic and green ***,a controllable cascade transformation of bromocyclization and aromatic bromination has also been smoothly achieved to form dibrominated HPIs and *** could be successfully scaled up under both the batch process and a continuous flow *** most remarkable peculiarity of our process over all previous methods is that the generated water is the major ***,successful application of this new protocol has been demonstrated by the pharmaceutical and natural products syntheses.

关键词： Tryptamines and tryptophols Nitrite Economic and sustainable bromocyclization HPI and TFI structures Bath and flow

Photo-induced 1,2-aryl migration of 2-chloro-1-arylpropanone under batch and flow conditions:Rapid,scalable and sustainable approach to 2-arylpropionic acids

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Chinese Chemical Letters 2024年第2期35卷 366-369页

作者： Qiao li Minjie liu Meifen Jiang li Wan Yingtang Ning Fen-er Chen College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China Engineering Center of Catalysis and Synthesis for Chiral Molecules Fudan UniversityShanghai 200433China Shanghai Engineering Center of Industrial Catalysis for Chiral Drugs Shanghai 200433China Institute of Pharmaceutical Science and Technology Zhejiang University of TechnologyHangzhou 310014China

We report the photo-mediated 1,2-aryl migration of 2‑chloro-1-arylpropanones to 2-arylpropionic acids using HCOONa as an acid *** pragmatically focused study obviates the multiple-step sequence in the industrially employed,ZnO-promoted rearrangement strategy,and offers rapid access to various 2-arylpropionic acids under environmentally friendly ***,the successful transfer of this batch photochemistry to a continuous flow platform led to improved scalability and enabled the gram-scale synthesis of loxoprofen.

关键词： Green chemistry Flow chemistry 2-Arylpropionic acids Photo-Favorskii reaction

The origins of catalytic selectivity for the electrochemical conversion of carbon dioxide to methanol

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Nano Research 2024年第1期17卷 5-17页

作者： Tian wang Yating wang Yuhang li Chunzhong li Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsFrontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Materials Science and EngineeringEast China University of Science&TechnologyShanghai 200237China School of Chemical Engineering East China University of Science&TechnologyShanghai 200237China

The electrocatalytic conversion of carbon dioxide(CO_(2))into useful fuels and chemical feedstocks is an emerging route to alleviate global warming and reduce reliance on fossil ***(CH_(3)OH),as one of the most significant and widely used liquid fuels that can be generated by CO_(2)reduction,is essential in the chemical *** this minireview,we unravel the origins of the selective formation of CH_(3)OH via CO_(2)reduction,including catalyst composition designs,local structure modulations,and electrolyte/catalyst interface ***,the remaining challenges and perspectives for the CO_(2)-to-CH_(3)OH reduction are proposed.

关键词： methanol carbon dioxide(CO_(2))reduction reaction electrochemistry electrocatalyst catalyst-electrolyte interface

Development of EPDM composites reinforced by CNTs@SiO_(2)for thermal protection systems of aerospace propulsion:Significant improvement in oxidation and ablation resistance properties

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Chinese Journal of Aeronautics 2024年第2期37卷 471-481页

作者： li wang Jiang li Kang li Yiwei wang Chenyang MA Science and Technology on Combustion Internal Flow and Thermal-Structure LaboratoryNorthwestern Polytechnical UniversityXi’an 710072China

Carbon Nanotubes(CNTs)reinforced Polymer-Matrix Composites(PMCs)is widely used as insulation materials in thermal protection system of aerospace ***,CNTs are prone to oxidation and have high thermal conductivities,which makes it difficult to improve the ablation resistance of insulation materials that contain ***_(2)was encapsulated onto the surface of CNTs(CNTs@SiO_(2)),which were then added to Ethylene Propylene Diene Monomer(EPDM)rubber to prepare the insulation *** analysis and ablation test were used to evaluate the resistance of the insulation materials to thermal oxidation and ***,scanning electron microscopy was performed to analyze their *** revealed that the addition of CNTs@SiO_(2)could visibly reduce the effects of hot corrosion and ablation on insulation *** C-CNTs@SiO_(2)-1 formulation had the best ablative ***,compared with the unencapsulated formulation(C-CNTs-10),the C-CNTs@SiO_(2)-1 formulation reduced the line ablation rate by 51%to 0.0130 mm/s after oxygen-acetylene ***,the ablation mechanism was investigated based on the effects of the CNTs@SiO_(2)additive on their ***,the improvement in ablation performance may be attributed to CNTs@SiO_(2)-induced decreases in thermal conductivity,improvement in the hot corrosion resistance in the char layer,and changes in the microstructure.

关键词： Polymer-Matrix Composites(PMCs) Carbon Nanotubes(CNTs) Thermal properties Ablation Oxidation