检索结果-南通市图书馆

Nano Research 2024年第6期17卷 4994-5001页

作者： Xitong Ren Jiajie Sun Yusen Li feng bai Key Laboratory for Special Functional Materials of Ministry of Education National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologySchool of Materials Science and Engineeringand Collaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004China School of Physics and Electronics Henan UniversityKaifeng 475004China

The combination of donor-acceptor(D-A)structures presents a viable strategy for fabricating covalent organic frameworks(COFs)with exceptional photocatalytic ***,the selection of functional groups on donor or acceptor building blocks and their effect on the macroscopic properties of COFs are *** this study,we tactfully synthesized a pair of Py-DBT-COFs from the same pyrene(Py)donor and 4,7-diphenylbenzo[c][1,2.5]thiadiazole(DBT)acceptor cores with distinct primitive functional *** primitive functional groups of building units determine the photocatalytic properties of corresponding ***,Py-C-DBT-COF synthesized from Py-4CHO and DBT-2.H_(2.showcases a splendid H_(2.evolution rate as high as 2.,377.7μmol/(g·h)(with 5 wt.%Pt)originating from better charge transfer capacity,which is significantly superior to that of Py-N-DBT-COF constructed from Py-4NH_(2.and *** distinct photocatalytic performances of the two COFs are demonstrated to originate from the different charge separation and transfer *** work supplies a new avenue for optimizing the photocatalytic performance of D-A COFs from the perspective of primitive functional group selections.

关键词： covalent organic frameworks functional group donor-acceptor photocatalysis

Deformation characteristics of ultra-deep circular shaft in soft soil:A case study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第3期16卷 239-260页

作者： Yafei Qiao feng Xie Zhanwei bai Jiafeng Lu Wenqi Ding Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China Engineering Project Management Company Shanghai Chengtou Water GroupShanghai 200002China SGIDI Engineering Consulting(Group)Co. Ltd.Shanghai 200093China

A circular shaft is often used to access a working well for deep underground space *** the depth of underground space increases,the excavation depth of the shaft *** this study,the deformation characteristics of a circular shaft with a depth of 56.3 m were presented and *** main monitoring contents included:(1)wall deflection;(2.vertical wall movement;(3)horizontal soil movement;(4)vertical surface movement;and(5)basal ***,the maximum wall deflection was only 7.7 *** with the wall deflection data collected for another 2. circular excavations,the ratio of maximum wall deflection to excavation depth of this shaft was smaller due to a smaller ratio of diameter to excavation *** wall deflection underwent two stages of deformation:the first stage was mainly circumferential compression caused by the mutual extrusion of joints between walls,and the second stage was typical vertical deflection *** horizontal soil movement outside the shaft was greater than the wall deflection and the deep soil caused great horizontal movement because of dewatering at confined water ***,a basal heave of 2.3.8 mm occurred in the pit centre near the ***,the shaft was uplifted over time and showed 3 stages of vertical *** surface outside the shaft exhibited settlement and uplift deformation at different locations due to different *** basal heave caused by excavation was the dominant factor,driving the vertical movement of the shaft as well as the surrounding *** correlation between the wall deflection and the surface settlement outside the shaft was weak.

关键词： Circular shaft Site monitoring Deflection Vertical deformation Soft soil

Self-doping active sites in microbe-derived carbonaceous electrocatalysts for the oxygen reduction reaction performance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 6803-6819页

作者： Xiaofeng Xiao Xiaochun Tian Junpeng Li Fan Yang Rui bai feng Zhao Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Microorganisms are rich in heteroatoms,which can be self-doped to form active sites during pyrolysis and loaded on microbederived carbonaceous *** recent years,microbe-derived carbonaceous materials,characterized with abundant selfdoping sites,have been continuously developed as cost-effective electrocatalysts for oxygen reduction reaction(ORR).To fully unlock the catalytic potential of microbe-derived carbonaceous materials,a comprehensive analysis of catalytic sites and mechanisms for ORR is *** paper provides a summary of the ORR catalytic performance of microbe-derived carbonaceous materials reported to date,with a specific focus on the self-doping sites introduced during their pyrolytic *** highlights the mono-or co-doping sites involving nonmetallic elements such as oxygen(O),nitrogen(N),phosphorus(P),and sulfur(S)atoms,as well as covers the doping of metallic iron(Fe)atoms with various coordination configurations in microbe-derived carbonaceous *** the impact of these self-doping sites on ORR catalytic performance can guide the design of doping sites in microbe-derived carbonaceous *** approach has the potential to maximize electrocatalytic activity of microbe-derived carbonaceous materials and contributes to the development of more efficient and cost-effective carbonaceous electrocatalysts.

关键词： electrocatalysis heteroatoms self-doped single atom catalyst microbe-derived carbonaceous material

Weak Fault Feature Extraction of the Rotating Machinery Using Flexible Analytic Wavelet Transform and Nonlinear Quantum Permutation Entropy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第6期79卷 4513-4531页

作者： Lili bai Wenhui Li He Ren feng Li TaoYan Lirong Chen College of Aeronautics and Astronautics Taiyuan University of TechnologyTaiyuan030024China Commercial Aircraft Corporation of China Ltd.Shanghai200126China College of Physics and Electronic Engineering State Key Laboratory of Quantum Optics and Quantum Optics DevicesShanxi UniversityTaiyuan030006China

Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extraction method that combines the Flexible Analytic Wavelet Transform(FAWT)with Nonlinear Quantum Permutation ***,leveraging fractional orders and arbitrary scaling and translation factors,exhibits superior translational invariance and adjustable fundamental oscillatory *** flexibility enables FAWT to provide well-suited wavelet shapes,effectively matching subtle fault components and avoiding performance degradation associated with fixed frequency partitioning and low-oscillation bases in detecting weak *** our approach,gearbox vibration signals undergo FAWT to obtain *** theory is then introduced into permutation entropy to propose Nonlinear Quantum Permutation Entropy,a feature that more accurately characterizes the operational state of vibration simulation *** nonlinear quantum permutation entropy extracted from sub-bands is utilized to characterize the operating state of rotating machinery.A comprehensive analysis of vibration signals from rolling bearings and gearboxes validates the feasibility of the proposed *** assessments with parameters derived from traditional permutation entropy,sample entropy,wavelet transform(WT),and empirical mode decomposition(EMD)underscore the superior effectiveness of this approach in fault detection and classification for rotating machinery.

关键词： Rotating machinery quantum theory nonlinear quantum permutation entropy Flexible Analytic Wavelet Transform(FAWT) feature extraction

A method for establishing a bearing residual life prediction model for process enhancement equipment based on rotor imbalance response analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第2期66卷 203-215页

作者： feng Wang Haoran Li Zhenghui Zhang Yan bai Hong Yin Jing Bian National Foundation Research Laboratory of Fault Prevention and Control in Hazardous Chemicals Production System Engineering Research Center of Chemical Technology SafetyBeijing University of Chemical TechnologyBeijing 100029China China Nuclear Power Engineering Co. LtdBeijing 100840China CNOOC Tianjin Chemical Research and Design Institute Co. LtdTianjin Key Laboratory of Energy and Chemical Explosion SafetyAcademician Expert Collaborative Innovation CenterTianjin 300131China

A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass *** the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material *** study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response *** method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing *** major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal *** implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data *** predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.

关键词： Rotating packed bed Mass imbalance Harmonic response analysis Residual life Prediction model

Characterization of mulberry leaf instant tea and evaluation of its hypolipidemia effect via regulation of intestinal microbiota

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第3期13卷 1348-1357页

作者： Xiaoyun Han Yunlong bai Xiaoxin feng Baochang Du Baojiang Zheng Qingshen Sun Engineering Research Center of Agricultural Microbiology Technology Ministry of Education&Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold RegionKey Laboratory of Molecular Biology&Key Laboratory of MicrobiologyCollege of Heilongjiang Province&School of Life SciencesHeilongjiang UniversityHarbin 150080China Gannan Forest Farm Qiqihaer 162100China College of Life Sciences Northeast Forestry UniversityHarbin 150040China

The purpose of this study was to characterize mulberry leaf instant tea(MLIT)powder prepared from the'Longsang No.1'(Morus abla *** 1)mulberry leaves in Heilongjiang Province(China)and assess its obesity-preventing/relieving effects.A total of 174 compounds including quercetin,chlorogenic acid,1-deoxyecomycin(1-DNJ)related to antihyperlipidemia effects were identified from the MLIT *** treatment reversed the Lee's index,fat coefficient,and serum biochemical parameters in both the obesity relieving and obesity preventing mice fed with high-fat *** the obesity relieving experiment,the relative abundance of Desulfovibrio in mouse feces decreased after both 0.5%and 1%MLIT *** obesity preventing experiments,mouse with different amount of MLIT treatments showed increased relative abundance of Akkermansia,Bifidobacterium and Lactobacillus,while Deferribacteres,Desulfobacterota *** beneficial bacteria in the intestinal tract of mice treated with MLIT *** study proved that MLIT had antihyperlipidemia potential via modulating intestinal microbiota in mice.

关键词： Mulberry leaf instant tea Liquid chromatography-mass spectrometry(LC-MS) Antihyperlipidemia Intestinal microbiota

Effects of 1 MeV electron radiation on the AlGaN/GaN high electron mobility transistors

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第9期45卷 70-75页

作者： Shijie Pan Shiwei feng Xuan Li Zixuan feng Xiaozhuang Lu Kun {2. Yamin Zhang College of Microelectronics Beijing University of TechnologyBeijing 100124China Institute of Microelectronics Chinese Academy of SciencesBeijing 100029China

In this study, the effects of 1 MeV electron radiation on the D-mode GaN-based high electron mobility transistors(HEMTs) were investigated after different radiation doses. The changes in electrical properties of the device were obtained, and the related physical mechanisms were analyzed. It indicated that under the radiation dose of 5 × 10^(14) cm^(-2., the channel current cannot be completely pinched off even if the negative gate voltage was lower than the threshold voltage, and the gate leakage current increased significantly. The emission microscopy and scanning electron microscopy were used to determine the damage location. Besides, the radiation dose was adjusted ranging from 5 × 10^(12. to 1 × 10^(14) cm^(-2., and we noticed that the drain-source current increased and the threshold voltage presented slightly negative shift. By calculations, it suggested that the carrier density and electron mobility gradually increased. It provided a reference for the development of device radiation reinforcement technology.

关键词： AlGaN/GaN HEMT electron radiation performance degradation device damage

Stability analysis of longwall top-coal caving face in extra-thick coal seams based on an innovative numerical hydraulic support model

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2024年第4期34卷 491-505页

作者： Jun Guo Wenbo Huang Guorui feng Jinwen bai Lirong Li Zi Wang Luyang Yu Xiaoze Wen Jie Zhang Wenming feng College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention Taiyuan University of TechnologyTaiyuan 030024China Shanxi Coking Coal Group Co. Ltd.Taiyuan 030024China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030024China

The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining *** view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working *** on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were ***,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution *** influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure ***,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.

关键词： Extremely thick coal seam Fully mechanized top coal caving Support strength Support-surrounding rock interaction

Uncovering Microstructure-Property Relationship in Ni-Alloyed Fe-Mn-Al-C Low-Density Steel Treated by Hot-Rolling and Air-Cooling Process

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 713-725页

作者： Xiaoliang Jia Guhui Gao Xiaolu Gui Chun feng R.D.K.Misra Bingzhe bai School of Mechanical Electronicand Control EngineeringBeijing Jiaotong UniversityBeijing100044China CNPC Tubular Goods Research Institute Xi’an710077China Laboratory for Excellence in Advanced Steel Research University of Texas at El PasoEl PasoTX79968-0521USA School of Material Science and Engineering Key Laboratory of Advanced Materials of Ministry of EducationTsinghua UniversityBeijing100084China

This paper focuses on the relationship between the microstructure and tensile properties of Fe-Mn-Al-C low-density high-strength steel processes by hot-rolling and air-cooling process. The microstructure analysis reveals that the combination of hot-rolling and air-cooling results in the formation of heterogeneous structures comprising different-sized γ and B_(2. phases in the low-density steel with the addition of nickel (Ni). The addition of Ni promotes the formation of the B_(2. phase and induces the pinning of B_(2. phase particles at the γ grain boundaries. This pinning effect effectively hinders the growth of the γ grains, leading to grain refinement. The tensile test results demonstrate that LDS-5Ni (low-density steel, LDS) exhibits excellent high strength and ductility combination, e.g., a tensile strength of 1535 MPa, yield strength of 1482.MPa, and elongation of 2..3%. These remarkable mechanical properties are primarily attributed to the combined strengthening contributions of grain refinement and duplex nano-sized second-phase precipitation hardening.

关键词： Low-density steel Microstructure B_(2.phase κ-Carbide Tensile properties

Charge-controlled compositional/microstructural regulations and electrochemical actuation performance of bulk nanoporous Ni-Pd alloys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第10期43卷 5305-5317页

作者： Fu-Quan Tan Qing-Guo bai Bin Yu Jian-feng Wang Zhong-Hua Zhang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) School of Materials Science and EngineeringShandong University School of Applied Physics and Materials Wuyi University Ira A.Fulton School of Engineering Arizona State University

Bulk nanoporous （np） metallic actuators have attracted increasing attention due to their large strain and low stimulation ***,studies focusing upon the combined effect of composition and structure on the actuation performance of metallic actuators are relatively scarce,and its underlying mechanism needs to be clarified Herein,a series of bulk np-NiPd samples with differen compositions and microstructures were fabricated using a dealloying-coarsening-dealloying strategy and chargecontrolled electrochemical dealloying,and the process involves only one component of precursor *** has been found that the np-NiPd cubes show a composition/structure-dependent mechanical property and electrochemical actuation ***,the npNi70Pd30sample with a homogeneously porous structure and good network connectivity exhibits significantly larger strain amplitude and faster strain rate than other hierarchically porous NiPd samples (np-Ni50Pd50and npNi2.Pd80).Moreover,the np-Ni70Pd30sample demonstrates good actuation stability with high strain retention after hundreds of ***,the maximum strain amplitude （1.17%） is even comparable to that of advanced leadfree piezoceramic,and the maximum strain rate exceeds those of many reported metallic actuator *** work indicates that good network connectivity plays a vita role in facilitating large/fast strain response in metallic actuators.

关键词： Actuation stability Bulk nanoporous NiPd Electrochemical dealloying Good network connectivity Metallic actuators