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Low-cost portable dielectric spectrometer based on mini-vector network analyzer and open-ended coaxial probe technology

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International Journal of Agricultural and Biological Engineering 2024年第3期17卷 166-172页

作者： zhuozhuo zhu Xinhua zhu Wenchuan Guo College of Mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100ShaanxiChina School of Physics and Electronic Information Yan'an UniversityYan'an 716000ShaanxiChina Shaanxi Research Center of Agricultural Equipment Engineering Technology Yangling 712100ShaanxiChina Key Laboratory of Agricultural Internet of Things Ministry of Agriculture and Rural AffairsYangling 712100ShaanxiChina Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service Yangling 712100ShaanxiChina

As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of ***,the large and expensive vector network analyzers(VNA)with expensive analysis software applied in measuring dielectric properties make research limited to the *** acquire dielectric spectra in situ,a model for solving relative complex permittivity was derived,and its performance was ***,a low-cost portable dielectric spectrometer with a mini VNA,a Raspberry Pi,and a coaxial probe as core parts was developed over the frequency range of 100-3000 *** stability and accuracy of the developed spectrometer were tested using milk and *** results indicated that the relative errors of the model were within±5%for dielectric constant(ε′)and loss factor(ε″).The coefficients of variation of measuredε′andε″by the developed spectrometer at 100-3000 MHz were less than 1%and 2%,*** with the dielectric properties obtained by using a commercial dielectric measurement system,the relative errors of measuredε′andε″were within±3.4%and±6.0%,*** study makes fast,non-destructive,and on-site food quality detection using dielectric spectra possible.

关键词： coaxial probe mini vector network analyzer low-cost portable dielectric spectrometer

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A rapid method of identifying mastitis degrees of bovines based on dielectric spectra of raw milk

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Food Quality and Safety 2023年第2期7卷 291-299页

作者：朱卓卓林碧莹朱新华郭文川 College of Mechanical and Electronic Engineering Northwest A&F UniversityYanglingChina School of Physics and Electronic Information Yan'an UniversityYan'anChina Shaanxi Research Center of Agricultural Equipment Engineering Technology YanglingChina Key Laboratory of Agricultural Internet of Things Ministry of Agriculture and Rural AffairsYanglingChina

Bovine mastitis is the most complex and costly disease in the dairy industry *** cell count(ScC)is accepted as an international standard for diagnosing mastitis in cows,but most instruments used to detect scC are expensive,or the detection speed is very *** develop a rapid method for identifying mastitis degree,the dielectric spectra of 301 raw milk samples at three mastitis grades,i.e.,negative,weakly positive,and positive grades based on ScC,were obtained in the frequency range of 20-450o MHz using coaxial probe *** im-portance in the projection method was used to select characteristic variables,and principal component analysis(PCA)and partial least squares(PLS)were used to reduce data *** discriminant analysis,support vector classification(SvC),and feed-forward neural network models were established to predict the mastitis degrees of cows based on 22 principal components and 24 latent variables obtained by PCA and PLS,*** results showed that the SvC model with PCA had the best classification performance with an accuracy rate of 95.8%for the prediction *** research indicates that dielectric spectroscopy technology has great potential in developing a rapid detector to diagnose mastitisincowsinsituoronline.

关键词： Mastitis somaticcellcount dielectric spectra qualitative analysis

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Few-shot incremental radar target recognition framework based on scattering-topology properties

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Chinese Journal of Aeronautics 2024年第8期37卷 246-260页

作者： Chenxuan LI Weigang zhu Bakun zhu Yonggang LI Graduate School Space Engineering UniversityBeijing 101400China Department of Electronic and Optical Engineering Space Engineering UniversityBeijing 101400China

The continuous emergence of new targets in open scenarios leads to a substantial decrease in the performance of Inverse Synthetic Aperture Radar(ISAR)recognition ***,data scarcity further exacerbates the challenge of identifying new classes of ISAR *** this paper,a few-shot incremental target recognition framework based on Scattering-Topology Properties(STPIL)is ***,STPIL extracts scattering-topology properties of ISAR targets as recognition ***,the pseudo-incremental training strategy effectively alleviates the algorithm’s forgetting of old knowledge,and improves compatibility with new ***,a feature embedding network,with few parameters,is designed based on the graph neural *** embedding network is highly adaptable to changes in data ***,STPIL fully considers the joint distribution and marginal distribution in scattering features,and uses the Brownian distance metric module to make the scattering-topology features more *** results on both the simulation dataset and the public measured data indicate that STPIL can effectively balance new classes with old classes,and has superior performance to other advanced methods in the incremental recognition of targets.

关键词： Brownian distance metric Graph neural networks Incremental learning Inverse Synthetic Aperture Radar(ISAR) Scattering

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Stress-strain relationship for reactive powder concrete with recycled powder under uniaxial compression

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1015-1027页

作者： Peng zhu Yunming zhu Wenjun QU Liyu XIE College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghai 200092China

The recycled powder(RP)from construction wastes can be used to partially replace cement in the preparation of reactive powder *** this paper,reactive powder concrete mixtures with RP partially replacing cement,and natural sand instead of quartz,are *** curing is used,instead of steam curing that is normally requested by standard for reactive powder *** influences of RP replacement ratio(0%,10%,20%,30%),silica fume proportion(10%,15%,20%),and steel fiber proportion(0%,1%,2%)are *** effects of RP,silica fume,and steel fiber proportion on compressive strength,elastic modulus,and relative absorption energy are analyzed,and theoretical models for compressive strength,elastic modulus,and relative absorption energy are established.A constitutive model for the uniaxial compressive stress-strain relationship of reactive powder concrete with RP is *** the increase of RP replacement ratio from 0% to 30%,the compressive strength decreases by 42% and elastic modulus decreases by 24%.

关键词： recycled powder reactive powder concrete elastic modulus relative absorbed energy stress-strain relationship

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Introduction to the first Jeme Tien Yow Lecture

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Underground Space 2024年第5期18卷 1-2页

作者： Hehua zhu Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The Jeme Tien Yow Lecture is in honor of *** Tien Yow(1861–1919),the pioneer of tunneling and underground space engineering in China and also renowned as the"Father of Modern Chinese Engineering".The lecture is hosted and organized by the journal of Underground ***-Min Zhang will deliver the first Jeme Tien Yow Lecture on May 26th,2024,at RM101,College of Civil Engineering,Tongji University,Shanghai,*** has submitted the corresponding research paper,coauthored with ***,for publication in the journal of Underground *** are delighted to see its publication together with this brief introduction.

关键词： journal underground Tie

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Carbon Emission Effects Driven by Evolution of Chinese Dietary Structure from 1987 to 2020

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Chinese Geographical Science 2024年第1期34卷 181-194页

作者： zhu Yuanyuan ZHANG Yan zhu Xiaohua Key Laboratory of Geographic Process Analysis&Simulation Hubei Province Central China Normal UniversityWuhan430079China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China

Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important *** study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary *** results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption *** dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality *** the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing *** per capita food carbon emissions of residents in urban and rural showed an overall upward *** total food carbon emissions in urban increased significantly,while that in rural increased first and then *** influence of beef and mutton on carbon emissions is the highest in dietary *** with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.

关键词： dietary structure structural evolution carbon emission effects carbon neutrality China

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Designing hierarchical structures for innovative cooling textile

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Nano Research 2024年第10期17卷 9202-9224页

作者： Xiran Du Jinlei Li Bin zhu Jia zhu National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210023China School of Sustainable Energy and Resources Nanjing UniversitySuzhou 215163China

The potential of personal cooling technologies in reducing air conditioning energy consumption and enhancing human thermal comfort is *** review focuses on recent advancements in hierarchical structure design for innovative cooling *** with insights into fundamental heat transfer processes between the human body,textile,and the surroundings,we uncover key control *** the advanced hierarchical structure designs enabling effective radiation,sweat evaporation,conduction management,and integration of cold energy sources for realizing effective human body cooling are systematically ***,we explore multifunctional designs beyond cooling,including switchable cooling-heating and ***,we engage in discussions on unifying cooling performance tests and additional multiple requirements to make strides toward practical *** review is anticipated to be a valuable resource,providing the scientific and industrial communities with a quick grasp of past advancements,current challenges,and future directions in achieving effective human body cooling.

关键词： thermal comfort personal cooling textile hierarchical structures

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Old Pinus massoniana forests benefit more from recent rapid warming in humid subtropical areas of central-southern China

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Journal of Forestry Research 2024年第5期35卷 155-170页

作者： Wenxin Li Liangjun zhu Lianhua zhu Mengdan Jing Censhi Qian Yu zhu Paolo Cherubini College of Life Science and Technology Central South University of Forestry and TechnologyChangsha 410004People’s Republic of China Swiss Federal Institute for Forest Snow and Landscape Research WSL8903 BirmensdorfSwitzerland Department of Forest and Conservation Sciences Faculty of ForestryUniversity of British Columbia2004-2424 Main MallVancouverBC V6T 1Z4Canada

Trees progress through various growth stages,each marked by specific responses and adaptation strate-gies to environmental *** the importance of age-related growth responses on overall forest health and management policies,limited knowledge exists regarding age-related effects on dendroclimatic relationships in key subtropical tree *** this study,we employed a den-drochronological method to examine the impact of rapid warming on growth dynamics and climatic sensitivity of young(40–60 years)and old(100–180 years)Pinus mas-soniana forests across six sites in central-southern *** normalized log basal area increment of trees in both age groups increased significantly following rapid warming in *** in young forests further showed a distinct growth decline during a prolonged severe drought(2004–2013),whereas those in old forests maintained growth *** growth was more strongly influenced by temperature than by moisture,particularly in old *** tem-peratures strongly and positively impacted the growth of old trees but had a weaker effect on young *** forests had a significantly lower resistance to extreme drought but faster recovery compared to young ***“divergence problem”was more pronounced in younger forests due to their heightened sensitivity to warming-induced drought and heat *** ongoing warming,young forests also may initially experience a growth decline due to their heightened sensitivity to winter *** findings underscore the importance of considering age-dependent changes in forest/tree growth response to warming in subtropical forest man-agement,particularly in the context of achieving“Carbon Peak&Carbon Neutrality”goals in China.

关键词： Tree rings Pinus massoniana Age effects Drought resilience Subtropical forests Rapid warming

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Synergistic catalysis of the N-hydroxyphthalimide on flower-like bimetallic metal-organic frameworks for boosting oxidative desulfurization

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Petroleum Science 2024年第1期21卷 674-682页

作者： Jing He Kun zhu Wei Jiang Dong-Ao zhu Lin-Hua zhu Hai-Yan Huang Wen-Shuai zhu Hua-Ming Li Institute for Energy Research Jiangsu UniversityZhenjiang212013JiangsuChina College of Chemistry and Chemical Engineering Hainan Normal UniversityKey Laboratory of Water Pollution Treatment and Resource Reuse of Hainan ProvinceHaikou571158HainanChina

Synergic catalytic effect between active sites and supports greatly determines the catalytic activity for the aerobic oxidative desulfurization of fuel *** this work,Ni-doped Co-based bimetallic metal-organic framework(CoNi-MOF)is fabricated to disperse N-hydroxyphthalimide(NHPI),in which the whole catalyst provides plentiful synergic catalytic effect to improve the performance of oxidative desulfurization(ODS).As a bimetallic MOF,the second metal Ni doping results in the flower-like morphology and the modification of electronic properties,which ensure the exposure of NHPI and strengthen the synergistic effect of the overall *** with the monometallic Co-MOF and naked NHPI,the NHPI@CoNi-MOF triggers the efficient activation of molecular oxygen and improves the ODS performance without an *** sulfur removal of dibenzothiophene-based model oil reaches 96.4%over the NHPI@CoNi-MOF catalyst in 8 h of ***,the catalytic product of this aerobic ODS reaction is sulfone,which is adsorbed on the catalyst surface due to the difference in *** work provides new insight and strategy for the design of a strong synergic catalytic effect between NHPI and bimetallic supports toward high-activity aerobic ODS materials.

关键词： Metal-organic frameworks Doped Bimetallic N-hydroxyphthalimide Aerobic processes Oxidative desulfurization

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A review of recent advances in the effects of surface and interface properties on marine propellers

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Friction 2024年第2期12卷 185-214页

作者： Manfu zhu Liran MA State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

Marine propellers are important propulsion devices for both surface ships and underwater *** severe environmental problems have required further performance enhancement for ***,traditional methods to improve propeller performances through geometrical and structural optimizations have been extensively investigated,while the underlying mechanisms of the effects of surface and interface properties on marine propellers are still far from being fully *** paper presented a comprehensive review of recent advances in the effects of surface and interface properties,such as surface roughness and surface wettability,on marine propellers with an emphasis on the significant improvements in both hydrodynamic and cavitation performances,hoping to arouse more in-depth investigations in the field of surface/interface science and technologies on marine propellers,and also promote the state-of-the-art technologies,such as superlubricity technology,into practical applications.

关键词： marine propellers hydrodynamics cavitation surface roughness surface wettability

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