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宽级配土离心试验地基模型落雨法分层机制与数值模拟

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岩土工程学报 2024年第S1期46卷 122-126页

作者：张旭东王永志王体强段雪锋袁晓铭中国地震局工程力学研究所地震工程与工程振动重点实验室黑龙江哈尔滨150080 地震灾害防治应急管理部重点实验室黑龙江哈尔滨150080

落雨法因其在模型制备过程与自然条件下砂土沉积过程相似,因而成为土工离心试验地基模型常用的模型制备手段,但是有关落雨法研究主要集中于相对密实度控制,而对于分层现象关注较少,尤其宽级配土。针对宽级配土落雨法制备过程出现的分层... 详细信息

落雨法因其在模型制备过程与自然条件下砂土沉积过程相似,因而成为土工离心试验地基模型常用的模型制备手段,但是有关落雨法研究主要集中于相对密实度控制,而对于分层现象关注较少,尤其宽级配土。针对宽级配土落雨法制备过程出现的分层现象,利用PFC3d数值模拟软件,探讨了落雨法制备过程分层现象的物理机制和出砂口落距、移动速度、宽度对分层现象的影响。结果表明:在真空介质中,粗细颗粒不出现分层现象;而在非真空介质中,粗、细颗粒出现了分层现象,原因为非真空环境下粗、细颗粒下落过程中产生了相对速度差,内在机制为粗、细颗粒半径不同受到平均表面流体阻力不同,从而造成不同粒径颗粒分离现象;随环境介质密度的增加,粗、细颗粒在下落过程中更易于发生分离,出砂口落距、移动速度和流量对分层现象具有一定程度影响。

关键词：落雨法宽级配土 PFC3d 分层现象分层机制

博落回提取物、金霉素及其联合添加对蛋鸡后备鸡生产性能、屠宰性能和胫骨质量的影响

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中国饲料 2024年第11期 99-106页

作者：祝凯李兆勇刘婕刘学峰杨在宾李会荣圣道生物(山东)集团有限公司山东泰安271000 山东农业大学动物科技学院山东泰安271018 山东省畜产品质量安全中心山东济南250109 临沂市畜牧场山东临沂276113

本试验旨在研究日粮中单独和联合添加博落回提取物、金霉素对0~17周龄蛋鸡生产性能、体重均匀度、屠宰性能和胫骨质量的影响,同时探讨博落回提取物替抗作用。选取健康1日龄海兰褐雌性雏鸡1440只,按照2×2析因设计,2个博落回提取物添加水... 详细信息

本试验旨在研究日粮中单独和联合添加博落回提取物、金霉素对0~17周龄蛋鸡生产性能、体重均匀度、屠宰性能和胫骨质量的影响,同时探讨博落回提取物替抗作用。选取健康1日龄海兰褐雌性雏鸡1440只,按照2×2析因设计,2个博落回提取物添加水平(不添加vs添加500 mg/kg),分别对应2个金霉素添加水平(不添加vs添加50 mg/kg)。随机分成4个处理,每个处理12个重复,每个重复30只鸡。各组分别饲喂基础日粮(Ⅰ组)、基础日粮+500 mg/kg博落回提取物(Ⅱ组)、基础日粮+50 mg/kg金霉素(Ⅲ组)、基础日粮+500 mg/kg博落回提取物和50 mg/kg金霉素(Ⅳ组)。试验期17周龄,1~7 d饲喂基础日粮,8 d开始饲喂各自的育雏期试验料,7周龄和13周龄分别开始饲喂育成前期和育成后期试验料。结果显示:(1)与对照组相比,博落回提取物组试验全期的料重比降低了2.29%(P0.05);日粮添加博落回提取物提高了不同时间段以及全期的日增重和体重,但未达到显著水平(P>0.05)。(2)与对照组相比,博落回提取物组、金霉素组、联合添加组的标准差、变异系数以及屠宰性能各项指标均无显著差异(P>0.05),但是,添加博落回提取物使6、12、17周龄的标准差和变异系数分别降低了3.03%和4.70%、8.54%和7.98%、9.61%和11.62%,屠宰性能指标均有不同程度提高。(3)与Ⅰ组、Ⅱ组、Ⅲ组相比,Ⅳ组6周龄的胫骨强度显著提高(P0.05)。与对照组相比,博落回提取物组6、12、17周龄胫骨重和胫骨强度提高,但差异不显著(P>0.05),使胫骨重分别提高了0.35%、6.09%、0.59%,胫骨强度分别提高了11.64%、6.41%、6.71%。综上所述,日粮添加博落回提取物可以提高体重和胫骨强度,降低料重比以及鸡群体重的标准差和变异系数;金霉素和两者联合添加对生产性能、屠宰性能、胫骨质量均无明显改善作用。因此,日粮中添加博落回提取物可以用来替代抗生素改善蛋鸡后备鸡生产性能和胫骨质量。

关键词：博落回提取物金霉素生产性能标准差变异系数屠宰性能胫骨质量

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不同采后处理对恭城月柿褐变、活性氧代谢及糖类的影响

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食品工业科技 2024年第11期45卷 260-269页

作者：盛金凤王雪峰雷雅雯易萍李丽唐雅园叶冬青严彩菱广西农业科学院农产品加工研究所广西南宁530007 广西果蔬贮藏与加工新技术重点实验室广西南宁530007

本文分析了有氧、真空和真空+1-MCP三种采后处理方式对脱涩后柿子贮藏过程中果实褐变、活性氧代谢和糖类的影响,并对褐变与各指标的相关性进行分析。真空和真空+1-MCP组柿子贮藏过程中的褐变指数BI低于有氧组,其中真空+1-MCP组褐变程度... 详细信息

本文分析了有氧、真空和真空+1-MCP三种采后处理方式对脱涩后柿子贮藏过程中果实褐变、活性氧代谢和糖类的影响,并对褐变与各指标的相关性进行分析。真空和真空+1-MCP组柿子贮藏过程中的褐变指数BI低于有氧组,其中真空+1-MCP组褐变程度最低;三种采后处理柿子贮藏过程中SOd、APX活性分别呈下降和上升的趋势,真空组柿子SOd活性最低,真空和真空+1-MCP条件下柿子APX活性高于有氧组;真空和真空+1-MCP抑制柿子CAT活性的增加,减少H2O2积累,同时抑制羟自由基的能力和抗坏血酸含量较低。真空和真空+1-MCP组柿子还原糖含量低于有氧组,其中真空+1-MCP组增加最慢,从贮藏开始时的14.10%增加至12 d时的14.87%;真空+1-MCP组柿子果胶含量下降缓慢。相关性分析可知,不同采后处理柿子贮藏过程中柿子褐变与各指标的相关性并不相同,但柿子褐变指数BI均与果胶呈负相关,与还原糖呈正相关。综合可知真空和真空+1-MCP条件更有利于抑制脱涩后月柿的褐变。

关键词：恭城月柿不同采后处理褐变活性氧代谢糖类

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A Morphology-driven Method for Measuring Technology Complementarity:Empirical Study Involving Alzheimer’s disease

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Journal of data and Information Science 2022年第3期7卷 20-48页

作者： xuefeng Wang Rongrong Li Yuqin Liu Ming Lei School of Management&Economics Beijing Institute of TechnologyHaidian DistrictBeijing 100081China School of Economics and Management China University of Petroleum(East China)QingdaoShandong 266580China School of Journalism and Publication Beijing Institute of Graphic CommunicationDaxing DistrictBeijing 102600China

Purpose:Measuring the exact technology complementarity between different institutions is necessary to obtain complementary technology resources for R&d ***/methodology/approach:This study constructs a morphology-driven method for measuring technology complementarity,taking medical field as an ***,we calculate semantic similarities between subjects(S and S)and action-objects(AO and AO)based on the Metathesaurus,forming clusters of S and AO based on a semantic similarity ***,we identify key technology issues and methods based on clusters of S and ***,a technology morphology matrix of several dimensions is constructed using morphology analysis,and the matrix is filled with subjects-action-objects(SAO)structures accord.ng to correspond.ng key technology issues and methods for different ***,the technology morphology matrix is used to measure the technology complementarity between different institutions based on ***:The improved technology complementarity method based on SAO is more of a supplementary and refined framework for the traditional IPC *** limitations:In future studies we will reprocess and identify the SAO structures which were not in the technology morphology matrix,and find other methods to characterize key technical issues and ***,we will add the comparison between proposed method and traditional and mostly used complementarity measurement method based on industry chain and industry *** implications:This study takes medical field as an *** morphology-driven method for measuring technology complementarity can be migrated and applied for any given ***/value:From the perspective of complementary technology resources,this study develops and tests a more accurate morphology-driven method for technology complementarity measurement.

关键词： Technology complementarity SAO structure Technology morphology analysis Alzheimer’s disease

Vortex tuning magnetization configurations in porous Fe_(3)O_(4) nanotube with wide microwave absorption frequency

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Nano Research 2022年第7期15卷 6743-6750页

作者： Ruixuan Zhang Lei Wang Chunyang Xu Chongyun Liang Xianhu Liu xuefeng Zhang Renchao Che Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative MaterialsDepartment of Materials ScienceFudan UniversityShanghai 200438China Joint-Research Center for Computational Materials Zhejiang LaboratoryHangzhou 311100China department of Chemistry Fudan UniversityShanghai 200433China School of Materials Science and Engineering Shanghai Institute of TechnologyShanghai 201418China Key Laboratory of Materials Processing and Mold Ministry of EducationZhengzhou UniversityZhengzhou 450002China Institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi UniversityHangzhou 310012China

The design and optimization of one-dimension(1d)magnetic material are of great importance for the energy conversion,storage and spin electron devices,which remain a huge ***,1d porous Fe_(3)O_(4) nanotubes(NTs)have been fabricated via a combined process of electrospinning and *** the electrospinning precursors,by regulating the content ratio between two types of polyvinyl pyrrolidone with different molecular weight,porous Fe_(3)O_(4) NTs with vortex-domain configuration have been *** on the unique 1d nanotube structure encapsulated with multi-domains,the composite Fe_(3)O_(4) NTs exhibit high complex permeability(μʹ,μʺ)values,and hold both strong magnetic storage and dissipation *** Fe_(3)O_(4) NTs exhibit excellent microwave absorption(MA)performance with the maximum reflection loss value of−57.1 dB and the efficient absorption bandwidth of 12.0 *** generated magnetic vortices make the crucial contribution to the spin-wave resonance which improves the MA dissipation under *** magnetic flux line distribution and magnetic domain moment were confirmed by the electron holography and micro-magnetic simulation,respectively,provid.ng the deep insight to the microwave absorption mechanism.

关键词： microwave absorption vortex domain one-dimensional structure porous structure

Optimizing magnetic/dielectric matching in permalloy/carbonized cotton fiber composites by strain-tunable ferromagnetic resonance and defect-induced dielectric polarization

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Journal of Materials Science & Technology 2022年第29期124卷 174-181页

作者： Xiaochen Shen Chenglong Hu Wenling Ren Rongzhi Zhao Lianze Ji xuefeng Zhang Xinglong d.ng Key Laboratory of Materials Modification by Laser Ion and Electron BeamsSchool of Materials Science and EngineeringDalian University of TechnologyDalian 116023China Key Laboratory for Anisotropy and Texture of Materials(MOE) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi UniversityHangzhou 310012China

Electromagnetic losses in composites could be synergistically controlled by permeability and permittivity,associated with multiple ferromagnetic resonances and dielectric ***,it is still challenging for simultaneous tunability for both the terms in a magnetic/dielectric composite ***,we demonstrate the tunable ferromagnetic resonances and the enhanced dielectric losses at gigahertz frequencies in permalloy/carbonized cotton fiber composites with different annealing *** is theoretically confirmed that the stress field acting on the magnetic permalloy layer increases with increasing temperature because of the shrinkage of the dielectric carbonized cotton fibers,resulting in multiple ferromagnetic resonances,in which there is a linear relationship(f=1.52×σ+9.38)between the resonance frequency(f)and the stress(σ).The present work provides a fundamental insight into understand.ng the micromagnetic dynamics of the magnetic/dielectric composite system.

关键词： Ferromagnetic resonance Stress tuning dielectric polarization

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

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Frontiers of Mechanical Engineering 2022年第1期17卷 160-177页

作者： Zhixian SHEN Laihao YAng Baijie QIAO Wei LUO xuefeng CHEN Ruqiang YAN School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an 710061China

Gear wear is one of the most common gear failures,which changes the mesh relationship of normal gear.A new mesh relationship caused by gear wear affects meshing excitations,such as mesh stiffness and transmission error,and further increases vibration and noise *** paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear.A geometric model for a new mesh relationship with gear wear is proposed,which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error(USTE).Based on the mesh stiffness and USTE considering gear wear,a gear dynamic model is established,and the vibration characteristics of gear wear are numerically *** with the experimental results verifies the proposed dynamic model based on the new mesh *** numerical and experimental results indicate that gear wear does not change the structure of the spectrum,but it alters the amplitude of the meshing frequencies and their *** condition indicators,such as root-mean-square,kurtosis,and first-order meshing frequency amplitude,can be regarded as important bases for judging gear wear state.

关键词： gear wear mesh relationship mesh stiffness transmission error vibration characteristics

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal materials

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机械工程前沿:英文版 2023年第2期18卷 33-97页

作者： Jin ZHAng xuefeng HUAng Xinzhen KAng Hao YI Qianyue WAng Huajun CAO College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China

Energy field-assisted machining technology has the potential to overcome the limitations of machining difficult-to-machine metal materials,such as poor machinability,low cutting efficiency,and high energy ***-speed dry milling has emerged as a typical green processing technology due to its high processing efficiency and avoidance of cutting ***,the lack of necessary cooling and lubrication in high-speed dry milling makes it difficult to meet the continuous milling requirements for difficult-to-machine metal *** introduction of advanced energy-field-assisted green processing technology can improve the machinability of such metallic materials and achieve efficient precision manufacturing,making it a focus of academic and industrial *** this review,the characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials,includ.ng titanium alloys,nickel-based alloys,and high-strength steel,are systematically *** laser energy field,ultrasonic energy field,and cryogenic minimum quantity lubrication energy fields are *** analyzing the effects of changing the energy field and cutting parameters on tool wear,chip morphology,cutting force,temperature,and surface quality of the workpiece during milling,the superiority of energy-field-assisted milling of difficult-to-machine metal materials is ***,the shortcomings and technical challenges of energy-field-assisted milling are summarized in detail,provid.ng feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine metal materials in the future.

关键词： difficult-to-machine metal material green machining high-speed dry milling laser energy fieldassisted milling ultrasonic energy field-assisted milling cryogenic minimum quantity lubrication energy field-assisted milling

Power Optimization Cooperative Control Strategy for Flexible Fast Interconnection device with Energy Storage

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Energy Engineering 2023年第8期120卷 1885-1897页

作者： Mingming Shi Jun Zhang xuefeng Ge Juntao Fei Jiajun Tan Electric Power Research Institute State Grid Jiangsu Electric Power Co.Ltd.Nanjing211103China Equipment Management department State Grid Jiangsu Electric Power Co.Ltd.Nanjing210029China Kunshan Power Supply Company State Grid Jiangsu Electric Power Co.Ltd.Suzhou215300China

With the wide application of renewable energy power generation technology,the distribution network presents the characteristics of multi-source and complex *** are potential risks in the stability of power system,and the problem of power quality is becoming more and more *** paper studies and proposes a power optimization cooperative control strategy for flexible fast interconnection device with energy storage,which combines the flexible interconnection technology with the energy storage *** primary technology is to regulate the active and reactive power of the *** comparing the actual power value of the converter with the reference value,the proportional integral(PI)controller is used for correction,and the current components of d and q axes are obtained and input to the converter as the reference value of the current inner *** control strategy in this paper can realize power mutual aid between feeders,and at the same time,the energy storage device can provide or absorb a certain amount of power for feeders,so that the power grid can realize stable operation in a certain range.

关键词： Flexible interconnection energy storage cooperative control