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Chinese Journal of Chemistry 2024年第4期42卷 343-350页

作者： Na Yao Juan Zhu Hongnan Jia Hengjiang cong Wei Luo College of Chemistry and Molecular Sciences Wuhan UniversityWuhanHubei430072 China

Developing highly efficient and low-cost electrocatalysts towards oxygen evolution reaction(OER)is essential for practical application in water electrolyzers and rechargeable metal-air *** Fe-based oxyhydroxides are regarded as state-of-the-art non-noble OER electrocatalysts,the origin of performance enhancement derived from Fe doping remains a hot topic of considerable ***,we demonstrate that in situ generated Fe vacancies in the pristine CoFeOOH catalyst through a pre-conversion process during alkaline OER result from dynamic Fe dissolution,identifying the origin of Fe-vacancy-induced enhanced OER *** functional theory(DFT)calculations and experimental results including X-ray absorption fine-structure spectroscopy,in situ UV-Vis spectroscopy,and in situ Raman spectroscopy reveal that the Fe vacancies could significantly promote the d-band center and valence states of adjacent Co sites,alter the active site from Fe atom to Co atom,accelerate the formation of high-valent active Co^(4+)species,and reduce the energy barrier of the potential-determining step,thereby contribute to the significantly enhanced OER performance.

关键词： CoFe oxyhydroxide Oxygen evolution reaction Fe vacancy Electrocatalysis Kinetics Reaction mechanisms

Coordinated Capacitor Voltage Balancing Method for Cascaded H-bridge Inverter with Supercapacitor and DC-DC Stage

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 191-201页

作者： Ye Zhang Zixin Li Fanqiang Gao cong Zhao Yaohua Li IEEE Key Laboratory of High Density Electromagnetic Power and Systems(Chinese Academy of Sciences) Institute of Electrical EngineeringChinese Academy of SciencesHaidian District University of Chinese Academy of Sciences Shijingshan District

Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dcdc stage in each submodule(SM), while a hybrid modulation strategy(HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCs. Finally, both simulation and experimental results verify the effectiveness of the presented method.

关键词： Cascaded H-bridge inverter(CHBI) Hybrid modulation strategy(HMS) Capacitor voltage balancing DClink voltage fluctuation Supercapacitor(SC)

Ion and electron motions in the outer electron diffusion region of collisionless magnetic reconnection

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Earth and Planetary Physics 2024年第3期8卷 472-478页

作者： cong Chang QuanMing Lu San Lu Kai Huang RongSheng Wang Deep Space Exploration Laboratory School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences(CAS)Center for Excellence in Comparative Planetology CAS Key Laboratory of Geospace EnvironmentHefei 230026China Collaborative Innovation Center of Astronautical Science and Technology Harbin 150001China

Two-dimensional particle-in-cell simulations are performed to study the coupling between ion and electron motions in collisionless magnetic *** electron diffusion region(EDR),where the electron motions are demagnetized,is found to have a two-layer structure:an inner EDR near the reconnection site and an outer EDR that is elongated to nearly 10 ion inertial lengths in the outflow *** the inner EDR,the speed of the electron outflow increases when the electrons move away from the X *** the outer EDR,the speed of the electron outflow first increases and then decreases until the electrons reach the boundary of the outer *** the boundary of the outer EDR,the magnetic field piles up and forms a depolarization *** the perspective of the fluid,a force analysis on the formation of electron and ion outflows has also been *** the X line,the electrons are accelerated by the reconnection electric field in the out-of-plane *** the electrons move away from the X line,we find that the Lorentz force converts the direction of the accelerated electrons to the x direction,forming an electron *** electric field forces and electron gradient forces tend to drag the electron *** acceleration along the x direction is caused by the Lorentz force,whereas the pressure gradient force tends to decelerate the ion *** these two terms are important,their effects on ions are almost *** Hall electric field force does positive work on ions and is not *** ions are continuously accelerated,and the ion and electron outflow velocities are almost the same near the depolarization front.

关键词： collisionless magnetic reconnection electron diffusion region force analysis particle-in-cell simulation

Insulation Design Rule for a Spacer in SF_(6)/N_(2)-filled DC Gas Insulated Apparatus

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 727-735页

作者： Hongyang Zhou Guoming Ma Meng Zhang cong Wang Youping Tu Chengrong Li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources and the Beijing Key Laboratory of High Voltage and EMC North China Electric Power UniversityBeijing 102206China

A recurring challenge of a DC SF_(6)/N_(2)-filled GIS/GIL apparatus is the charge accumulation at DC *** conventional design rules and knowledge of AC spacers may not be applicable for this new type of apparatus.A novel design rule is proposed considering the effect of accumulated charge on the threshold of electric field strength being resistant to the superposed voltage.A surface charge accumulation simulation model is introduced,and the key parameters in the simulation model are *** addition,an experimental platform for a 100 kV spacer flashover test is *** flashover tests under superimposed voltage with opposing polarities are carried out,and the withstanding voltage of the spacer is ***,based on the proposed model,the threshold of the surface electric field strength(tangential component)on the DC spacer in SF_(6)/N_(2) mixed gases is *** a reliable insulation design of a DC GIS/GIL apparatus filled with 0.7 MPa SF_(6)/N_(2),the threshold of surface electric field strength on the DC spacer is 12 kV/*** insulation design rule can be referenced in the design of a high-voltage DC SF_(6)/N_(2)-filled GIS/GIL apparatus.

关键词： Charge accumulation DC spacer flashover voltage SF_(6)/N_(2) threshold of surface electric field strength

Experimental investigation on effective aerosol scavenging using different spray configurations with pre-injection of water mist for Fukushima Daiichi decommissioning

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Nuclear Science and Techniques 2024年第5期35卷 154-172页

作者： Rui-cong Xu Avadhesh Kumar Sharma Erdal Ozdemir Shuichiro Miwa Shunichi Suzuki Department of Nuclear Engineering and Management The University of Tokyo7‑3‑1 HongoBunkyo‑KuTokyo 113‑8656Japan Nuclear Professional School The University of Tokyo2‑2

During the decommissioning of the Fukushima Daiichi nuclear power plant,it is important to consider the retrieval of resolidified debris both in air and underwater *** the subsequent retrieval of debris from the reactor building,the resolidified debris must be cut into smaller pieces using various cutting *** the cutting process,aerosol particles are expected to be generated at the submicron *** has been noted that such aerosols sizing within the Greenfield gap(0.1-1μm)are difficult to remove effectively using traditional spraying ***,to improve the aerosol removal efficiency of the spray system,a new aerosol agglomeration method was recently proposed,which involves injecting water mist to enlarge the sizes of the aerosol particles before removing them using water *** this study,a series of experiments were performed to clarify the proper spray configurations for effective aerosol scavenging and to improve the performance of the water *** experimental results showed that the spray flow rate and droplet characteristics are important factors for the aerosol-scavenging efficiency and performance of the water *** results obtained from this study will be helpful for the optimization of the spray system design for effective aerosol scavenging during the decommissioning of the Fukushima Daiichi plant.

关键词： Fukushima Daiichi decommissioning Aerosol scavenging Multiphase flow Spray system Aerosol-mist agglomeration

Transfer matrix method for free and forced vibrations of multi-level functionally graded material stepped beams with different boundary conditions

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 983-1000页

作者： Xiaoyang SU Tong HU Wei ZHANG Houjun KANG Yunyue cong Quan YUAN School of Civil Engineering and Architecture Guangxi UniversityNanning 530004China Scientific Research Center of Engineering Mechanics Guangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures Guangxi UniversityNanning 530004China

Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical *** study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving *** the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable ***,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are *** demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also *** this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried *** results show the accuracy and efficiency of the TMM.

关键词： transfer matrix method(TMM) free vibration forced vibration functionally graded material(FGM) stepped beam

Crack mechanism of ground fissures in loess layer of Fenwei Basin, China

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Journal of Mountain Science 2024年第5期21卷 1683-1696页

作者： LI cong LU Quanzhong WANG Feiyong LUO Wenchao XU Qiang School of Geological Engineering and Geomatics Chang’an UniversityXi’an 710054China Key Laboratory of Western Mineral Resources and Geological Engineering Ministry of EducationXi’an 710054China Observation and Research Station of Ground Fissure and Land Subsidence Ministry of Natural ResourcesXi’an 710054China School of Engineering and Technology China University of GeosciencesBeijing 100083China

The Fenwei Basin, covered by loess, experiences severe ground fissure disasters. These disasters disrupt the continuity of the loess and pose significant threats to engineering construction safety along transportation routes. Nevertheless, the crack characteristics and the influence zone of ground fissures in the loess layer remain inadequately investigated. To effectively prevent and control ground fissure disasters, physical model tests and the PFC(particle flow code) numerical simulation method are used to investigate the crack mechanism of buried ground fissures in the loess layer. The results show that there are two main cracks in the layer profile, which have a Y-shape morphology. As the dip angle of the preset cracks increased from 60° to 90°, the main deformation zone at the surface gradually shifted towards the footwall. The process of crack propagation from depth to surface is divided into five stages. Additionally, the results confirm the accuracy of the width of the rupture zone d2in the footwall calculated by the cantilever beam theory. These findings can offer theoretical guidance for determining the avoidance distance of ground fissures in loess regions, as well as for implementing disaster prevention and corresponding control measures for various stages of buried ground fissure propagation.

关键词： Ground fissure Fenwei Basin Physical model test Particle flow code Crack propagation

Intestinal malrotation complicated with gastric cancer: A case report

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World Journal of Clinical Cases 2024年第1期12卷 210-216页

作者： Xiang-Hao Jia Shuai Kong Xin-Xin Gao Bi-cong cong Chun-Ning Zheng School of Clinical Medicine Weifang Medical UniversityWeifang 261053Shandong ProvinceChina Department of Gastrointestinal Surgery Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250000Shandong ProvinceChina

BACKGROUND Intestinal malrotation is a congenital defect of embryonic development caused by various teratogenic *** this condition,the intestinal tube,along with the superior mesenteric artery serving as the axis for the counterclockwise movement,is incomplete or abnormally rotated due to incomplete attachment of the mesentery and abnormal intestinal tube *** a case is usually asymp-tomatic and thus difficult to ***,similar variant malformations are only found during an operation required for other abdominal *** SUMMARY An elderly male patient was admitted to the hospital due to gastric *** abdominal computed tomography(CT)scan with contrast revealed that the ascending and descending colon were parallel on the right side of the abdominal cavity,while the sigmoid colon extended into the right iliac fossa,allowing the diagnosis of congenital midgut *** thorough preoperative preparation,the patient underwent laparoscopic radical gastrectomy to treat his gastric ***,an exploration of the abdominal cavity uncovered the absence of the transverse *** distal colon at the hepatic flexure,along with the ascending colon,extended into the right iliac fossa,where it continued as the sigmoid *** planned,the laparoscopic radical gastrectomy was perform-ed,and the patient was discharged from the hospital 7 d after the *** Asymptomatic intestinal malrotation is best detected by CT,requiring no treatment but possibly interfering with the treatment of other diseases.

关键词： Intestinal malrotation congenital malformation Gastric cancer Abdominal

Detection of Pb in Tieguanyin tea and ash by laser-induced breakdown spectroscopy

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Optoelectronics Letters 2024年第2期20卷 116-121页

作者： LI Jingwen YAO Lixing SHEN Li WANG cong Tianjin Key Laboratory of Quantum Optics and Intelligent Photonics School of ScienceTianjin University of TechnologyTianjin 300384China1

In this work, laser-induced breakdown spectroscopy(LIBS) was applied for the detection of Pb in Tieguanyin tea and ash. Firstly, the Tieguanyin tea and ash containing Pb were prepared, and the difference of intensities of Pb I spectral lines before and after the ashing treatment was studied. It was found that the intensities of Pb I lines increased by 30 times and the standard deviation of background signal decreased by 41% after the ashing treatment. Therefore, the enrichment of Pb element by ashing treatment was used to detect Pb in tea with high sensitivity. Then, the calibration curve of Pb was established using spectral lines without self-absorption, and the determination coefficient(R^(2)) for the linear fitting of calibration curve was 0.979 9. Finally, it was found that the limit of detection of Pb was 233.8 ppb. Compared with the results of other works which detect Pb directly, the enrichment of Pb by ashing treatment improved the detection sensitivity of Pb by about 200 times. In addition, this method can be applied to the high sensitivity detection of other heavy metals, such as Cr, Cd, Hg, etc in plants, Chinese herbal medicine, flour, rice, coal and other solid materials.

关键词： breakdown spectroscopy treatment

Prognostic factors associated with gastrointestinal dysfunction after gastrointestinal tumor surgery:A meta-analysis

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World Journal of Gastrointestinal Surgery 2024年第5期16卷 1420-1429页

作者： Jia Song cong Zhou Tian Zhang Department of Operating Room The Fourth Affiliated Hospital of Nanjing Medical UniversityNanjing 210031Jiangsu ProvinceChina Department of Gastrointestinal Surgery Tongji Hospital of Huazhong University of Science and TechnologyWuhan 430073Hubei ProvinceChina Department of Disinfection Supply Center The Fourth Affiliated Hospital of Nanjing Medical UniversityNanjing 210031Jiangsu ProvinceChina

BACKGROUND Explore the risk factors of gastrointestinal dysfunction after gastrointestinal tumor surgery and to provide evidence for the prevention and intervention of gastrointestinal dysfunction in patients with gastrointestinal tumor *** To investigate the potential risk factors for gastrointestinal dysfunction following gastrointestinal tumor surgery and to present information supporting the prevention and management of gastrointestinal dysfunction in surgery *** Systematically searched the relevant literature from PubMed,Web of Science,Cochrane Library,Embase,CNKI,China Biomedical Database,Wanfang Database,and Weipu Chinese Journal Database self-established until October 1,*** Manager 5.3 software was used for meta-analysis after two researchers independently screened literature,extracted data,and evaluated the risk of bias in the included *** A total of 23 pieces of literature were included,the quality of which was medium or above,and the total sample size was *** results of meta-analysis showed that the patients were male(OR=1.58,95%CI:1.25-2.01,P=0.002)and≥60 years old(OR=2.60,95%CI:1.76-2.87,P<0.001),physical index≥25.3 kg/m2(OR=1.6,95%CI:1.00-1.12,P=0.040),smoking history(OR=1.89,95%CI:1.31-2.73,P<0.001),chronic obstructive pulmonary disease(OR=1.49,95%CI:1.22-1.83,P<0.001),enterostomy(OR=1.47,95%CI:1.26-1.70,P<0.001),history of abdominal surgery(OR=2.90,95%CI:1.67-5.03,P<0.001),surgical site(OR=1.2,95%CI:1.40-2.62,P<0.001),operation method(OR=1.68,95%CI:1.08-2.62,P=0.020),operation duration(OR=2.65,95%CI:1.92-3.67,P<0.001),abdominal adhesion grade(OR=2.52,95%CI:1.90-3.56,P<0.001),postoperative opioid history(OR=5.35,95%CI:3.29-8.71,P<0.001),tumor TNM staging(OR=2.58,95%CI:1.84-3.62,P<0.001),postoperative blood transfusion(OR=2.92,95%CI:0.88-9.73,P=0.010)is a risk factor for postoperative gastrointestinal dysfunction in patients with gastrointestinal *** There are many factors affecting gastroint

关键词： Gastrointestinal tumor surgery Postoperative gastrointestinal dysfunction Intestinal paralysis Risk factors Metaanalysis