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Nano Research 2024年第6期17卷 4720-4728页

作者： Liting wei Kaini Zhang rui Zhao lei Zhang Yan Zhang Suyi Yang Jinzhan Su International Research Center for Renewable Energy&State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China Department of Applied Chemistry Yuncheng UniversityYuncheng 044000China

NiFe-based electrocatalysts will experience dynamical surface reconstruction during oxygen evolution reaction(OER)process,and the derived metal(oxy)hydroxide hybrids on the surface have been considered as the actual active species for *** efforts have been dedicated to understanding the surface reconstruction,but there is rare research on recognizing the origin of improved performance derived from anion species of ***,the OER electrocatalytic characteristics were tuned with different anions in NiFe-based catalyst,using NiFe-based oxides/nitride/sulfide/selenides/phosphides(NiFeX,X=O,N,S,Se,and P)as the model *** combination of X-ray photoelectronic spectroscopy,electrochemical tests,operando spectroscopic characterizations,and density functional theory(DFT)calculations,reveals that anion with lower electronegativity in NiFe-based catalyst leads to higher conductivity and delayed valence transition of Ni sites,as well as optimized adsorption behavior towards oxygen intermediates,contributing to enhanced OER ***,NiFeP electrocatalyst demonstrates an ultralow overpotential of 265 mV at 20 mA·cm−2 for OER,as well as long-term *** work not only offers further insights into the effect of anionic electronegativity on the intrinsic OER electrocatalytic properties of NiFe-based electrocatalyst but also provides guide to design efficient non-noble metal-based electrocatalysts for water oxidation.

关键词： oxygen evolution reaction(OER) anion species electronegativity valence transition

Dynamics of an ultrasound contrast agent microbubble near spherical boundary in ultrasound field

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Chinese Physics B 2019年第11期28卷 204-209页

作者： Ji-Wen Hu Lian-Mei Wang Sheng-You Qian Wen-Yi Liu Ya-Tao Liu wei-rui lei School of Mathematics and Physics University of South ChinaHengyang 421001China School of Physics and Electronics Hunan Normal UniversityChangsha 410081China

The goal of this article is to establish the conditions of excitation where one has to deal with ultrasound contrast agent(UCA) microbubbles pulsating near biological tissues with spherical boundary in ultrasound field for targeted drug delivery and cavitation-enhanced thrombolysis, etc., and contributes to understanding of mechanisms at play in such an interaction. A modified model is presented for describing microbubble dynamics near a spherical boundary(including convex boundary and concave boundary) with an arbitrary-sized aperture angle. The novelty of the model is such that an oscillating microbubble is influenced by an additional pressure produced by the sound reflection from the boundary wall. It is found that the amplitude of microbubble oscillation is positively correlated to the curve radius of the wall and negatively correlated to the aperture angle of the wall and the sound reflection coefficient. Moreover, the natural frequency of the microbubble oscillation for such a compliable wall increases with the wall compliance, but decreases with the reduction of the wall size, indicating distinct increase of the natural frequency compared to a common rigid wall. The proposed model may allow obtaining accurate information on the radiation force and signals that may be used to advantage in related as drug delivery and contrast agent imaging.

关键词： ultrasound contrast agent(UCA) microbubble spherical boundary ultrasound natural frequency

Recent Advances in the Electrochemical Defluorinative Transformations of C-F Bonds

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Chinese Journal of Chemistry 2024年第16期42卷 1913-1928页

作者： Qinhui Wan rui-Xue Liu Zhongyi Zhang Xia-Die Wu Zhong-wei Hou lei Wang Advanced Research Institute and Schoolof Pharmaceutical Sciences Taizhou UniversityJiaojiangZhejiang 318000China Department of Chemistry Southern University of Science and TechnologyhenzhenGuangdong 518055China College of Material Chemistry and Chemical Engineering Key Laboratory of Organosilicon Chemistry and Material Technology Ministryof EducationHangzhou Normal UniversityHangzhouZhejiang 311121China

Organic fluorine compounds are ubiquitous and pivotally important organic molecules,yet their activation and transformation have long been a formidable challenge due to the high energy and low reactivity of C-F *** electrosynthesis,an environmentally benign synthetic method in organic chemistry,enables a myriad of chemical transformations without the need for external redox *** recent years,organic electrochemistry has emerged as a powerful tool for achieving the activation and transformation of C-F bonds in fluorine-containing *** review aims to succinctly recapitulate the latest advancements in the electrochemical defluorinative transformations of C-F bonds and to delve into the reaction design,mechanistic insights,and developmental prospects ofthese methods.

关键词： Organic electrochemistry Electroreduction Defluorination C-F bond activation Organic fluorine compounds

Cyclohexanol optimizes Pt/ionomer interface in fuel cell cathodes

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Science China Chemistry 2024年第2期67卷 417-419页

作者： lei Tong Hai-wei Liang Hefei National Research Center for Physical Sciences at the Microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei230026China

This highlight is based on a recent article published in Nature Catalysis, in which wei's group [1] from Chongqing University proposes a novel approach to enhance the performance of proton exchange membrane fuel cells(PEMFCs)by adjusting the interface between Pt and ionomer in the cathode catalyst layer. Their strategy involves adding cyclohexanol to the cathode catalyst ink to impede the adsorption of sulfonate groups from the ionomer onto Pt nanoparticles, which results in the release of Pt activity sites and a significant improvement in the mass transport efficiency.

关键词： interface catalyst adding

Long-Chain Alkenones in the South Yellow Sea Sediments and Their Indicative Significance for Haptophytes Species

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Journal of Ocean University of China 2024年第5期23卷 1287-1296页

作者： XU Yakun YANG Xinxin XIAO rui XING lei Key Laboratory of Marine Chemistry Theory and Engineering Technology Ministry of Education Ocean University of China Laboratory of Marine Ecology and Environment Science Qingdao National Laboratory for Marine Science and Technology

Long-chain alkenones（LCAs） have been widely used as important biomarkers in palaeoceanographic ***,the commonly used LCAs proxies are mainly based on C37alkenones,and it is still lack of the studies about the distribution and indications of LCAs with different chain lengths other than ***,the composition and distribution of LCAs were analyzed in surface sediments from the southern Yellow Sea（SYS） and a sedimentary core（A02-C） from the central Yellow Sea（YS）mud *** results showed that C37,C38and C39alkenones were the major LCAs in surface sediments of the SYS,and the relative contents of C38:2Et,C37:2Me,C37:3Me,C38:2Me,C38:3Et,C38:3Me,C39:2Et and C39:3Et were 18.3%-59.8%,22.6%-41.2%,7.4%-23.0%,6.6%-15.4%,3.8%-13.3 %,3.6%-8.7%,2.8%-6.0% and 0.7%-3.0%,*** the relationships of U38MeK-U38EtKand U37K'-U38EtKindicate that LCAs are mainly derived from Emiliania huxleyi（***）.High ratios of total C37alkenones to total C38alkenones(K37/K38)（1-1.2） were found in the central SYS,corresponding to the relatively high abundance of ***;while low ratios of K37/K38（0.7-0.9） were observed at nearshore area of the SYS where Gephyrocapsa oceanica（***） has relatively high *** spatial distribution of K37/K38ratio is also consistent with that of coccolithophores nannofossil in the *** addition,K37/K38ratio in core A02-C varied from 0.7 to 1.1 with a gradual decreasing trend during the past 5.5 *** suggests that the relative abundance of *** decreased gradually,caused by the changes in the Yellow Sea Warm Current（YSWC） and the East Asian Winter Monsoon（EAWM） during this period.

关键词： alkenones sediment southern Yellow Sea Yellow Sea Warm Current

Core-shell mesoporous carbon hollow spheres as Se hosts for advanced Al-Se batteries

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 899-906页

作者： Haiping lei Tianwei wei Jiguo Tu Shuqiang Jiao State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Incorporating a selenium(Se)positive electrode into aluminum(Al)-ion batteries is an effective strategy for improving the overall battery ***,the cycling stability of Se positive electrodes has challenges due to the dissolution of intermediate reaction *** this work,we aim to harness the advantages of Se while reducing its limitations by preparing a core-shell mesoporous carbon hollow sphere with a titanium nitride(C@TiN)host to load 63.9wt%Se as the positive electrode material for Al-Se *** the physical and chemical confinement offered by the hollow mesoporous carbon and TiN,the obtained core-shell mesoporous carbon hollow spheres coated with Se(Se@C@TiN)display superior utilization of the active material and remarkable cycling *** a result,Al-Se batteries equipped with the as-prepared Se@C@TiN composite positive electrodes show an initial discharge specific capacity of 377 mAh·g^(-1)at a current density of 1000 mA·g^(-1)while maintaining a discharge specific capacity of 86.0 mAh·g^(-1)over 200 *** improved cycling performance is ascribed to the high electrical conductivity of the core-shell mesoporous carbon hollow spheres and the unique three-dimensional hierarchical architecture of Se@C@TiN.

关键词： aluminum-selenium batteries intermediate products core-shell mesoporous carbon hollow sphere cycling performance

Effects of Number of Bleed Holes on Shock-Wave/Boundary-Layer Interactions in a Transonic Compressor Stator

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Journal of Thermal Science 2024年第2期33卷 611-624页

作者： LI Bai ZHOU Xun LUO lei DU wei School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous *** bleed holes are arranged on the suction surface in a single row,two staggered rows and three staggered *** each bleed scheme,five bleed pressure ratios are examined at an inlet Mach number of *** results indicate that the aerodynamic performance of the cascade is significantly improved by the porous *** the single-row scheme,the maximum reduction in total pressure losses is 57%.For the two-staggered-row and three-staggered-row schemes,there is an optimal bleed pressure ratio of 1.0,and the maximum reductions in total pressure loss are 68% and 75%,*** low loss in the cascade is due to the well-controlled boundary *** new local supersonic region created by the bleed hole is the key reason for the improved boundary *** vortex induced by side bleeding provides another mechanism for delaying flow *** the bleed holes could create multiple local supersonic regions,which reduce the range of the adverse pressure gradient that the boundary layer needs to *** is the reason why cascades with more bleed holes perform better.

关键词： transonic compressor stator shock wave/boundary layer interaction porous bleed number of bleed holes

Performance analysis and multi-objective optimization based on a modified irreversible Stirling cycle

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Science China(Technological Sciences) 2024年第6期67卷 1668-1684页

作者： XU lei YU MinJie LIU ZhiChun LIU wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China

The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle *** obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accurate heat transfer process in Stirling engines based on a thermodynamic function called available *** finite-time thermodynamic method is used to analyze the model performance under constant heat source temperature,finite temperature difference heat transfer,and incomplete regenerative processes.A new polytropic process is introduced to model the heat transfer between the working fluid and external heat sources in which only heat above ambient temperature is converted into technical *** regenerator is divided into numerous smaller heat reservoirs with individual temperature to analyze the incomplete regenerative *** expressions of the output power and thermal efficiency are obtained based on the modified irreversible Stirling cycle,and the effects of irreversible losses are analyzed to evaluate the performance of the proposed *** indicate that the efficiency of the modified cycle is much lower than that of the ideal Stirling cycle with an isothermal *** the increase of the average heat transfer temperature difference,there exists an optimum value for the power of the irreversible *** optimum power of the model was obtained for varying thermodynamic parameters by optimizing the average heat transfer temperature difference between the hot and cold *** optimize the irreversible model,the multi-objective optimization analysis is carried out based on NSGA-Ⅱ,which results in an optimized output power of 40.87 kW and an optimized thermal efficiency of 44%.

关键词： stirling cycle regenerative processes isopotential processes multi-objective optimization finite time thermodynamics

Modulated-ISRJ rejection using online dictionary learning for synthetic aperture radar imagery

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Journal of Systems Engineering and Electronics 2024年第2期35卷 316-329页

作者： wei Shaopeng ZHANG lei LU Jingyue LIU Hongwei College of Oceanography and Space Informatics China University of Petroleum(East China)Qingdao 266580China School of Electronics Engineering Xidian UniversityXi’an 710071China School of Electronics and Communication Engineering Shenzhen Campus of Sun Yat-sen UniversityGuangzhou 518107China School of Computer Science and Technology Xidian UniversityXi’an 710071China

In electromagnetic countermeasures circumstances,synthetic aperture radar(SAR)imagery usually suffers from severe quality degradation from modulated interrupt sampling repeater jamming(MISRJ),which usually owes considerable coherence with the SAR transmission waveform together with periodical modulation *** paper develops an MISRJ suppression algorithm for SAR imagery with online dictionary *** the algorithm,the jamming modulation temporal properties are exploited with extracting and sorting MISRJ slices using fast-time *** dictionary learning is followed to separate real signals from jamming *** the learned representation,time-varying MISRJs are suppressed *** simulated and real-measured SAR data are also used to confirm advantages in suppressing time-varying MISRJs over traditional methods.

关键词： synthetic aperture radar(SAR) modulated interrupt sampling jamming(MISRJ) online dictionary learning

An effective strategy of constructing multi-metallic oxides of ZnO/ CoNiO_(2)/CoO/C microflowers for improved supercapacitive performance

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Chinese Journal of Chemical Engineering 2024年第3期67卷 1-8页

作者： wei Guo Yan Zhang Xiaxin lei Shuang Wang College of Physics Taiyuan University of TechnologyJinzhong 030600China College of Environmental Science and Engineering Taiyuan University of TechnologyJinzhong 030600China Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization Taiyuan University of TechnologyTaiyuan 030024China

In this work,a new ZnO/CoNiO_(2)/CoO/C metal oxides composite is prepared by cost-effective hydrothermal method coupled with annealing process under N_(2) ***,the oxidation-defect annealing environment is conducive to both morphology and component of the composite,which flower-like ZnO/CoNiO_(2)/CoO/C is *** from good chemical stability of ZnO,high energy capacity of CoNiO_(2) and CoO and good conductivity of C,the as-prepared sample shows promising electrochemical behavior,including the specific capacity of 1435 C·g^(-1) at 1 A·g^(-1),capacity retention of 87.3%at 20 A·g^(-1),and cycling stability of 90.5%for 3000 cycles at 5 A·g^(-1),***,the prepared ZnO/CoNiO_(2)/CoO/C/NF//AC aqueous hybrid supercapacitors device delivers the best specific energy of 55.9 W·h·kg^(-1) at 850 W·kg^(-1).The results reflect that the as-prepared ZnO/CoNiO_(2)/CoO/C microflowers are considered as high performance electrode materials for supercapacitor,and the strategy mentioned in this paper is benefit to prepare mixed metal oxides composite for energy conversion and storage.

关键词： Composites Electrochemistry Hydrothermal Transition metal oxides Structural control Supercapacitors