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Palladium single atoms from melting nanoparticles on WO_(3-x) for boosted hydrogen evolution reaction

Journal of Energy Chemistry 2024年第4期91卷 637-644页

作者： Zhongmiao Gong Zhigang Chen Hao li Guang Yang Min Yuan zhiyun li Xueying Wan Yi Cui School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026AnhuiChina i-lab Vacuum Interconnected Nanotech WorkstationSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123JiangsuChina School of Materials Science and Engineering Chongqing University of TechnologyChongqing 400054China Key Laboratory of Precision and Intelligent Chemistry School of Chemistry and Materials ScienceHefei National Research Center for Physical Sciences at the MicroscaleNational Synchrotron Radiation LaboratorySchool of Nuclear Science and TechnologyUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

Surface-supported isolated atoms in single-atom catalysts(SACs)grant maximum utilization of metals in heterogeneous catalysis.Herein,we report a feasible pyrolysis strategy to synthesize Pd single atoms by thermally melting Pd nanoparticles on an oxygen-vacancy-rich tungsten-oxide matrix at reduction atmosphere.Near ambient pressure X-ray photoelectron spectroscopy was used to monitor the formation of zero-valence Pd single atoms and the increased metallic feature of WO_(3-x)substrate.Accordingly,the as-obtained zero-valence Pd single-atom catalyst exhibits a markedly boosted HER activity with a low overpotential(η_(10)=70 mV)at the current density of 10 mA/cm2and a small Tafel slope(b=68 mV/dec),nearly 150 mV and a 3,0-fold enhancement than those of Pd nanoparticles(η_(10)=220 mV,b=133 mV/dec)under the same conditions.In addition,quasi in situ XPS results suggest the hydrogen spillover effect is more likely to occur on Pd single atoms during the electrochemical process.Our work may pave an interesting route for the rational design of highly-efficient single-atom catalysts,and the elucidation of corresponding enhanced reaction mechanisms by the utilization of advanced characterization techniques.

关键词： Pd WO_(3-x) Single-atom catalysts NAP-XPS HER

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The dynamic surface evolution of halide perovskites induced by external energy stimulation

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National Science Review 2024年第4期11卷 185-194页

作者： Feiyu Cheng Pengdong Wang Chenzhe Xu Qingliang liao Suicai Zhang Haochun Sun Wenqiang Fan Guodong liu zhiyun li Yaping Kong li Wang Fangsen li Zhuo Kang Yue Zhang Academy for Advanced Interdisciplinary Science and Technology State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing Key Laboratory for Advanced Energy Materials and Technologies Key Laboratory of Advanced Materials and Devices for Post-Moore ChipsMinistry of EducationBeijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology Beijing Vacuum Interconnected Nanotech Workstation(Nano-X) Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of Sciences Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

Tracking the dynamic surface evolution of metal halide perovskite is crucial for understanding the corresponding fundamental principles of photoelectric properties and intrinsic instability. However, due to the volatility elements and soft lattice nature of perovskites, several important dynamic behaviors remain unclear. Here, an ultra-high vacuum（UHV） interconnection system integrated by surface-sensitive probing techniques has been developed to investigate the freshly cleaved surface of CH3NH3PbBr3in situ under given energy stimulation. On this basis, the detailed three-step chemical decomposition pathway of perovskites has been clarified. Meanwhile, the evolution of crystal structure from cubic phase to tetragonal phase on the perovskite surface has been revealed under energy stimulation. Accompanied by chemical composition and crystal structure evolution, electronic structure changes including energy level position,hole effective mass, and Rashba splitting have also been accurately determined. These findings provide a clear perspective on the physical origin of optoelectronic properties and the decomposition mechanism of perovskites.

关键词： metal halide perovskite external energy stimulation surface dynamic evolution surface electronic structure ultra-high vacuum interconnection system

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Influence of Repetitive Impulse Waveforms on Surface Discharge Characteristics and Insulation life for Polyimide Film

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 746-755页

作者： zhiyun Han Qingmin li Yujin Guo Tao liu Guojing Dong Hanwen Ren State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Electric Power Research Institute Beijing 100085China Inner Mongolia Electric Economy and Technology Academy Hohhot 010020China

Accelerated insulation aging problems under high frequency repetitive impulses in power electronic transformers are drawing more and more attention in modern power systems. Partial discharge (PD) characteristics including discharge inception voltage, phase distribution and statistical characteristics on polyimide (PI) surface under different impulse waveforms and the insulation life of PI films are studied in this paper. We carry out experiments based on PD and insulation lifetime test systems, using five different types of repetitive impulses, including three bipolar waves and two unipolar waves. The experimental results show that there is little variation in discharge inception voltage under different waveforms, but great variation in phase distribution and statistical characteristics of PD. In addition, insulation life is approximately the same under different waveforms with the same polarity, and the aging rate under bipolar waveforms is larger than that under unipolar waveforms. We explain the differences between the bipolar and unipolar waveforms on insulation life, which can be concluded that the surface charge under unipolar waveform accumulates more significnatly compared with bipolar waveform and decreases the electric filed strength in discharging the air gap and inhibits surface discharge from occurring.

关键词： Insulation life polyimide film power electronic transformer repetitive impulse surface discharge characteristics

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Boosting oxygen reduction activity and CO_(2) resistance on bismuth ferrite-based perovskite cathode for low-temperature solid oxide fuel cells below 600℃

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Journal of Energy Chemistry 2024年第3期90卷 600-609,I0013页

作者： Juntao Gao zhiyun Wei Mengke Yuan Zhe Wang Zhe Lü Qiang li lingling Xu Bo Wei School of Physics Harbin Institute of TechnologyHarbin 150001HeilongjiangChina Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080HeilongjiangChina School of Physics and Electronic Engineering Harbin Normal UniversityHarbin 150025HeilongjiangChina

Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.

关键词： Low-temperature solid oxide fuel cell Perovskite cathode DFT calculations CO_(2) tolerance

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Insights into the dwarfing mechanism of pear(Pyrus betulaefolia) based on anatomical and structural analysis using X-ray scanning

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Horticultural Plant Journal 2024年第2期10卷 355-366页

作者： lili Dong Chuxuan Yang Jing Wang Jingjing li Mei Zhao Dingli li zhiyun Qiu Chunhui Ma Zhenhua Cui College of Horticulture Qingdao Agricultural UniversityQingdaoShandong 266109China College of Landscape and Forestry Qingdao Agricultural UniversityQingdaoShandong 266109China

The lack of a suitable rootstock to control scion growth has limited the development of high-density plantations in pear production, which is partly attributed to poor understanding of the dwarfing mechanism. In the present study, the rootstock of the dwarf-type pear (Pyrus betulaefolia)PY-9’ was identified and used as the material for anatomical analysis.PY-9’ grew to half the tree height of the normal cultivar Zhengdu’, along with fewer internodes and shorter length. Significant differences in growth rate betweenPY-9’ andZhengdu’ were detected at approximately 30 days after full bloom, which corresponded with the time of the greatest difference in water potential between the dwarf and normal cultivar.PY-9’ showed a higher photosynthetic rate thanZhengdu’. Anatomical analysis showed thatPY-9’ had higher area ratios of both phloem and xylem and more developed vascular tissues thanZhengdu’. The three-dimensional reconstructed skeleton of the xylem from X-ray computed tomography scanning revealed greater intervessel connectivity inZhengdu’ than inPY-9’, which could contribute to the more vigorous growth ofZhengdu’. This study thus provides the first comparison of the microstructural properties of xylem elements between a dwarfing-type and vigorous-type pear rootstock, providing new insights into the dwarfing mechanism in pear and facilitating breeding of dwarf pear rootstocks to increase crop productivity.

关键词： Pyrus betulaefolia Anatomical analysis Dwarfing mechanism Intervessel connectivity Rootstock

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Recent development on COX-2 inhibitors as promising anti-inflammatory agents:The past 10 years

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Acta Pharmaceutica Sinica B 2022年第6期12卷 2790-2807页

作者： Zhiran Ju Menglan li Junde Xu Daniel C.Howell zhiyun li Fen-Er Chen Institute of Pharmaceutical Science and Technology Zhejiang University of TechnologyHangzhou 310014China Engineering Center of Catalysis and Synthesis for Chiral Molecules Fudan UniversityShanghai 200433China Shanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs Shanghai 200433China Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals Zhejiang University of TechnologyHangzhou 310014China

Cyclooxygenases play a vital role in inflammation and are responsible for the production of prostaglandins.Two cyclooxygenases are described,the constitutive cyclooxygenase-1 and the inducible cyclooxygenase-2,for which the target inhibitors are the non-steroidal anti-inflammatory drugs(NSAIDs).Prostaglandins are a class of lipid compounds that mediate acute and chronic inflammation.NSAIDs are the most frequent choices for treatment of inflammation.Nevertheless,currently used anti-inflammatory drugs have become associated with a variety of adverse effects which lead to diminished output even market withdrawal.Recently,more studies have been carried out on searching novel selective COX-2 inhibitors with safety profiles.In this review,we highlight the various structural classes of organic and natural scaffolds with efficient COX-2 inhibitory activity reported during 2011-2021.It will be valuable for pharmaceutical scientists to read up on the current chemicals to pave the way for subsequent research.

关键词： Inflammation Cyclooxygenase Prostaglandins Adverse effects COX-2 inhibitors

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Interfacial dynamics of GaP/Si(100) heterostructure grown by molecular beam epitaxy

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Journal of Semiconductors 2022年第12期43卷 32-38页

作者： Tieshi Wei Xuefei li zhiyun li Wenxian Yang Yuanyuan Wu Zhiwei Xing Shulong Lu Key Laboratory of Nanodevices and Applications Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Nano Science and Technology Institute University of Science and Technology of ChinaSuzhou 215123China Vacuum Interconnected Nanotech Workstation(NANO-X) Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China

The atomic structure and surface chemistry of GaP/Si(100)heterostructure with different pre-layers grown by molecu-lar beam epitaxy are studied.It is found that GaP epilayer with Ga-riched pre-layers on Si(100)substrate has regular surface mor-phology and stoichiometric abrupt heterointerfaces from atomic force microscopes(AFMs)and spherical aberration-corrected transmission electron microscopes(ACTEMs).The interfacial dynamics of GaP/Si(100)heterostructure is investigated by X-ray photoelectron spectroscopy(XPS)equipped with an Ar gas cluster ion beam,indicating that Ga pre-layers can lower the inter-face formation energy and the bond that is formed is more stable.These results suggest that Ga-riched pre-layers are more con-ducive to the GaP nucleation as well as the epitaxial growth of GaP material on Si(100)substrate.

关键词： XPS interfacial dynamics GaP/Si(100)heterostructure MBE

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Growth,coalescence,and etching of two-dimensional overlayers on metals modulated by near-surface Ar nanobubbles

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Nano Research 2022年第3期15卷 2706-2714页

作者： Wei Wei Jiaqi Pan Haiping lin Chanan Euaruksakul zhiyun li Rong Huang li Wang Zhujun Wang Qiang Fu Yi Cui Vacuum Interconnected Nanotech Workstation Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Institute of Functional Nano&Soft Materials(FUNSOM) Soochow UniversitySuzhou 215123China Synchrotron light Research Institute Nakhon Ratchasima 30000Thailand School of Physical Science and Technology Shanghai Tech UniversityShanghai 200031China Scientific Center for Optical and Electron Microscopy ETH Zürich8093 ZürichSwitzerland State Key Laboratory of Catalysis iChEMDalian Institute of Chemical Physicsthe Chinese Academy of SciencesDalian 116023China

The synthesis of high-quality ultrathin overlayers is critically dependent on the surface structure of substrates,especially involving the overlayer–substrate interaction.By using in situ surface measurements,we demonstrate that the overlayer–substrate interaction can be tuned by doping near-surface Ar nanobubbles.The interfacial coupling strength significantly decreases with near-surface Ar nanobubbles,accompanying by an“anisotropic to isotropic”growth transformation.On the substrate containing near-surface Ar,the growth front crosses entire surface atomic steps in both uphill and downhill directions with no difference,and thus,the morphology of the two-dimensional(2D)overlayer exhibits a round-shape.Especially,the round-shaped 2D overlayers coalesce seamlessly with a growth acceleration in the approaching direction,which is barely observed in the synthesis of 2D materials.This can be attributed to the immigration lifetime and diffusion rate of growth species,which depends on the overlayer–substrate interaction and the surface catalysis.Furthermore,the“round to hexagon”morphological transition is achieved by etching-regrowth,revealing the inherent growth kinetics under quasi-freestanding conditions.These findings provide a novel promising way to modulate the growth,coalescence,and etching dynamics of 2D materials on solid surfaces by adjusting the strength of overlayer–substrate interaction,which contributes to optimization of large-scale production of 2D material crystals.

关键词： two dimensional materials overlayer–substrate interaction near-surface Ar nanobubbles evolution behavior surface dynamics

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Phase field model for electric-thermal coupled discharge breakdown of polyimide nanocomposites under high frequency electrical stress

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Plasma Science and Technology 2024年第2期26卷 114-124页

作者：韩智云李庆民李俊科王梦溪任瀚文邹亮 State Key Lab of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206People's Republic of China School of Electrical Engineering Shandong UniversityJinan 250061People's Republic of China

In contrast to conventional transformers, power electronic transformers, as an integral component of new energy power system, are often subjected to high-frequency and transient electrical stresses, leading to heightened concerns regarding insulation failures. Meanwhile, the underlying mechanism behind discharge breakdown failure and nanofiller enhancement under high-frequency electrical stress remains unclear. An electric-thermal coupled discharge breakdown phase field model was constructed to study the evolution of the breakdown path in polyimide nanocomposite insulation subjected to high-frequency stress. The investigation focused on analyzing the effect of various factors, including frequency, temperature, and nanofiller shape, on the breakdown path of Polyimide(PI) composites. Additionally, it elucidated the enhancement mechanism of nano-modified composite insulation at the mesoscopic scale. The results indicated that with increasing frequency and temperature, the discharge breakdown path demonstrates accelerated development, accompanied by a gradual dominance of Joule heat energy. This enhancement is attributed to the dispersed electric field distribution and the hindering effect of the nanosheets. The research findings offer a theoretical foundation and methodological framework to inform the optimal design and performance management of new insulating materials utilized in high-frequency power equipment.

关键词： dielectric discharge breakdown high frequency power electronic transformer polyimide nanocomposites phase field model

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Early-life famine exposure,adulthood obesity patterns,and risk of low-energy fracture

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Frontiers of Medicine 2024年第1期18卷 192-203页

作者： Hongyan Qi Chunyan Hu Jie Zhang lin lin Shuangyuan Wang Hong lin Xiaojing Jia Yuanyue Zhu Yi Zhang Xueyan Wu Mian li Min Xu Yu Xu Tiange Wang zhiyun Zhao Weiqing Wang Yufang Bi Meng Dai Yuhong Chen Jieli Lu Department of Endocrine and Metabolic Diseases Shanghai Institute of Endocrine and Metabolic DiseasesRuijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China Shanghai National Clinical Research Center for Endocrine and Metabolic Diseases Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the People’s Republic of ChinaShanghai National Center for Translational MedicineRuijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China

Malnutrition in early life increases the risk of osteoporosis,but the association of early-life undernutrition combined with adulthood obesity patterns with low-energy fracture remains unknown.This study included 5323 community-dwelling subjects aged⩾40 years from China.Early-life famine exposure was identified based on the participants’birth dates.General obesity was assessed using the body mass index(BMI),and abdominal obesity was evaluated with the waist-to-hip ratio(WHR).Low-energy fracture was defined as fracture occurring after the age of⩾40 typically caused by falls from standing height or lower.Compared to the nonexposed group,the group with fetal,childhood,and adolescence famine exposure was associated with an increased risk of fracture in women with odds ratios(ORs)and 95%confidence intervals(CIs)of 3.55(1.57–8.05),3.90(1.57–9.71),and 3.53(1.05–11.88),respectively,but not in men.Significant interactions were observed between fetal famine exposure and general obesity with fracture among women(P for interaction=0.0008).Furthermore,compared with the groups with normal BMI and WHR,the group of women who underwent fetal famine exposure and had both general and abdominal obesity had the highest risk of fracture(OR,95%CI:3.32,1.17–9.40).These results indicate that early-life famine exposure interacts with adulthood general obesity and significantly increases the risk of low-energy fracture later in life in women.

关键词： famine obesity body mass index waist-to-hip ratio low-energy fracture

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