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HYDRAULIC CHARACTERIZATIONS OF TORTUOUS FLOW IN PATH DRIP IRRIGATION EMITTER

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Journal of Hydrodynamics 2006年第4期18卷 449-457页

作者： LI Yun-kai yang pei-ling REN Shu-mei XU Ting-wu College of Hydraulic and Civil Engineering China Agricultural University Beijing 100083 China International College at Beijing China Agricultural University Beijing 100083 China

At present, the tortuous emitter has the most advanced performances in drip irrigation. But the theories and methods for designing its flow path have been strictly confidential and the researches on the function of practical guidance have seldom been published. Seven types of most representative tortuous emitting-pipes currently used in agricultural irrigation regions of China were chosen for investigating the geometric parameters of the flow path by means of combining high-precision microscope and AutoCAD technology. By the measurement platform developed by the authors for hydraulic performances of emitters, the free discharge rates from the 7 types of emitters were measured at 9 pressure levels of 1.5 m, 3.0 m, 5.0 m, 7.0 m, 9.0 m, 10.0 m, 11.0 m, 13.0 m and 15.0 m. Then the discharge-pressure relationship, manufacturing variation coefficient, average velocity on the cross-section of flow path and the critical Reynolds number for the flow regime transformation within the paths were analyzed in detail. The results show that both pressure-ascending work pattern and pressure-descending work pattern have some impacts on the discharge rates of tortuous emitters, but the impact level is not significant. The target pressure could be approached by repetitive applications of the two work patterns during pressure regulation. The operation under low pressures has some impacts on the hydraulic performances of emitters, but the impact level is also not significant. The classical model of the discharge-pressure relationship is suitable for the pressure range of 1.5 m -15.0 m. The Reynolds number for fluids within the 7 types of tortuous emitters ranges from Re=105 to Re =930. The critical Reynolds number for the flow regime transformation is smaller than that for the routine dimension flow path. The variation coefficient of emitter discharge rates is slightly fluctuating around a certain value within the whole pressure range.

关键词： drip irrigation emitters tortuous flow pathhydraulic performances flow characteristics

Characteristics and Driven Factors of Nitrous Oxide and Carbon Dioxide Emissions in Soil Irrigated with Treated Wastewater

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Journal of Integrative Agriculture 2012年第8期11卷 1354-1364页

作者： XUE Yan-dong yang pei-ling LUO Yuan-pei LI Yun-kai REN Shu-mei SU Yan-ping NIU Yong-tao College of Water Resources and Civil Engineering China Agricultural University Beijing 100083 P.R.China Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences Beijing 100081 P.R. China

The reuse of treated wastewater in agricultural systems could partially help alleviate water resource shortages in developing countries. Treated wastewater differs from fresh water in that it has higher concentrations of salts, Escherichia coli and presence of dissolved organic matter, and inorganic N after secondary treatment, among others. Its application could thus cause environmental consequences such as soil salinization, ammonia volatilization, and greenhouse gas emissions. In an incubation experiment, we evaluated the characteristics and effects of water-filled pore space （WFPS） and N input on the emissions of nitrous oxide （N2O） and carbon dioxide （CO2） from silt loam soil receiving treated wastewater. Irrigation with treated wastewater （vs. distilled water） significantly increased cumulative N2O emission in soil （117.97 μg N kg-1）. Cumulative N2O emissions showed an exponentially increase with the increasing WFPS in unamended soil, but the maximum occurred in the added urea soil incubated at 60% WFPS. N2O emissions caused by irrigation with treated wastewater combined with urea-N fertilization did not simply add linearly, but significant interaction （P〈0.05） caused lower emissions than the production of N2O from the cumulative effects of treated wastewater and fertilizer N. Moreover, a significant impact on cumulative CO2 emission was measured in soil irrigated with treated wastewater. When treated wastewater was applied, there was significant interaction between WFPS and N input on N2O emission. Hence, our results indicated that irrigation with treated wastewater should cause great concern for increasing global warming potential due to enhanced emission of N2O and CO2.

关键词： treated wastewater nitrous oxide carbon dioxide water-filled pore space urea

Carbon dots-derived three-dimensional-ordered macroporous host with high penetrability and catalytic activity for LSBs under lean electrolyte

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Rare Metals 2024年第6期43卷 2560-2573页

作者： Jiao-Zi Duan Hua-Yu pei Quan yang Xue Li Xin Ba Xue Yong Jun-ling Guo Si-Yu Lu Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou 450001China Country State Center for International Cooperation On Designer Low-Carbon&Environmental Materials School of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China Hubei Institute of Quality Supervision Inspection Wuhan 430061China Department of Chemistry University of SheffieldSheffeld S37HFUK

The practical energy density of lithium-sulfur batteries(LSBs)is seriously limited by the high electrolyte-to-sulfur ratios(E/S).The E/S can be reduced by employing hosts with easy-to-infiltrate structure that ensures the uniform distribution of a lean electrolyte and high catalytic activity that can suppress"shuttle effect"via accelerating the slow conversion of soluble poly sulfides to insoluble *** the easy-to-infiltrate structures,the three-dimensional-ordered macroporous(3DOM)structure is easier to scale preparation and more suitable for the existing industrial ***,it is difficult to obtain the 3DOM with(1)high penetrability due to the high viscosity of frequently-used organic polymer precursors and(2)high catalytic activity due to the low confinement effect,meaning that uniformly dispersed small-sized catalytic materials are difficult to load on ***,using carbon dots(CDs)with both organic and inorganic properties as a precursor and aggregation limiting agent,a 3DOM host with high penetrability and homodispersed Ni particles of small sizes(Ni-CDs-3DOM)was *** this host:(1)CDs precursor with suitable viscosity can improve the penetrability.(2)CDs can effectively inhibit the agglomeration of Ni particles.(3)Uniformly dispersed small-size Ni particles offer high-efficiency catalytic activity toward sulfur ***,the Ni-CDs-3DOM/sulfur cathode exhibits high sulfur utilization and stable cycling performance even under high sulfur loading(5.5 mg·cm^(-2))and low E/S(6.5μl·mg^(-1)).This work indicates the usefulness of CDs in constructing hosts for LSBs with high energy density.

关键词： Lithium-sulfur batteries Carbon dots Catalytic action Easy-to-infiltrate structure Lean electrolyte

Nrf2-mediated ferroptosis of spermatogenic cells involved in male reproductive toxicity induced by polystyrene nanoplastics in mice

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第4期25卷 307-323页

作者： Xufeng FU Hang HAN Hong yang Bo XU Wenjie DAI ling LIU Tiantian HE Xing DU Xiuying pei Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education School of Basic Medical SciencesNingxia Medical UniversityYinchuan 750004China Key Laboratory of Reproduction and Genetics in Ningxia Ningxia Medical UniversityYinchuan 750004China

Microplastics(MPs)and nanoplastics(NPs)have become hazardous materials due to the massive amount of plastic waste and disposable masks,but their specific health effects remain *** this study,fluorescence-labeled polystyrene NPs(PS-NPs)were injected into the circulatory systems of mice to determine the distribution and potential toxic effects of NPs in ***,whole-body imaging found that PS-NPs accumulated in the testes of ***,the toxic effects of PS-NPs on the reproduction systems and the spermatocytes cell line of male mice,and their mechanisms,were *** oral exposure to PS-NPs,their spermatogenesis was affected and the spermatogenic cells were *** spermatocyte cell line GC-2 was exposed to PS-NPs and analyzed using RNA sequencing(RNA-seq)to determine the toxic mechanisms;a ferroptosis pathway was found after PS-NP *** phenomena and indicators of ferroptosis were then determined and verified by ferroptosis inhibitor ferrostatin-1(Fer-1),and it was also found that nuclear factor erythroid 2-related factor 2(Nrf2)played an important role in spermatogenic cell ferroptosis induced by ***,it was confirmed in vivo that this mechanism of Nrf2 played a protective role in PS-NPs-induced male reproductive *** study demonstrated that PS-NPs induce male reproductive dysfunction in mice by causing spermatogenic cell ferroptosis dependent on Nrf2.

关键词： Polvstyrene nanoplastics(PS-NPs) Reproductive toxicity Ferroptosis Nuclear factor ervthroid 2-related factor 2(Nrf2)

Structural engineered living materials

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Nano Research 2024年第2期17卷 715-733页

作者： yang Geng Zian Jia ling Li 635 Prices Fork Road Department of Mechanical EngineeringVirginia Polytechnic Institute and State UniversityBlacksburg VA24061USA

Biological structural materials not only exhibit remarkable mechanical properties but also often embody dynamic characteristics such as environmental responsiveness,autonomy,and self-healing,which are difficult to achieve in conventional engineering *** merging materials science,synthetic biology,and other disciplines,engineered living materials(ELMs)provide a promising solution to combine living organisms with abiotic components,thus facilitating the construction of functional“living”*** natural materials,ELMs possess vitality and hold immense application potential in areas such as medicine,electronics,and construction,captivating increasing research attention *** an emerging branch of ELMs,structural ELMs aim to mimic living biological structural materials by achieving desired mechanical performance while maintaining important“living”*** we summarize the recent progress and provide our perspectives for this emerging research *** first summarize the superiority of structural ELMs by reviewing biological structural materials and biomimetic material design ***,we provide a systematic discussion on the definition and classifications of structural ELMs,their mechanical performance,and physiological ***,we summarize some critical challenges faced by structural ELMs and highlight directions of future *** hope this review article can provide a timely summary of the state of the art and relevant perspectives for future development of structural ELMs.

关键词： structural materials engineered living materials(ELMs) structural ELMs composites mechanical properties

Progress and prospects of graphene-based materials in lithium batteries

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Rare Metals 2024年第5期43卷 1886-1905页

作者： Shen Lai Tao Huang pei Liu Hong-Bin Wang Shi-Chun yang Xin-Hua Liu Kai yang Qian-ling Zhang Jian-Hong Liu Jiang-Tao Hu Graphene Composite Research Center College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Shenzhen Eigen-Equation Graphene Technology Co.Ltd Shenzhen518060China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Department of Electrical and Electronic Engineering Advanced Technology InstituteUniversity of SurreyGuildfordSurrey GU27XHUK

Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side reactions,stabilization of electrode architecture,and improvement of conductive ***,extensive fundamental research on this aspect has been performed so ***,when it comes to large-scale industrial applications,the utilization of graphene-based materials progresses at a very slow ***,there presents a severe technological decoupling between academic research and industrial application,and there is an urgent need to link ***,in order to address current issues of graphene-based materials used in lithium batteries,we present their latest advancements with stateof-the-art *** applications of graphenebased materials in practical lithium batteries are highlighted and predicted to bridge the gap between the academic progress and industrial manufacture,thereby paving the way for accelerating the development of graphenebased material as well as lithium battery industry.

关键词： Lithium batteries Graphene-based materials Academic research Industrial application Development direction

Terminal attitude selection method of missile attack aircraft

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Chinese Journal of Aeronautics 2024年第2期37卷 385-400页

作者： Peng HOU yang pei Yuxue GE Mengjie ZHU School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Research Department Shanghai Electro-Mechanical Engineering InstituteShanghai 201108China

The appropriate terminal attitude of missile is important to improve the damage effectiveness of fragmentation warhead against aircraft *** this paper,three missile terminal attitude selection methods are proposed to solve the problem of terminal attitude selection in different situations according to their respective evaluation *** MVE-based method uses the damage probability of each detonation point around the aircraft at a given attitude of missile to calculate the Mean Volume of Effectiveness(MVE)at the corresponding attitude,and then uses the MVE for different attitudes to select the terminal strike *** detonation position-based method addresses the case where the missile detonation position can be assessed in *** the effects of missile guidance errors and fuze activation position errors,Monte Carlo simulations are used to calculate the damage probability of aircraft with different strike attitudes,from which the terminal strike attitude is *** BP-ANN model-based method uses the constructed Back Propagation Artificial Neural Network(BP-ANN)model instead of simulation to calculate the evaluation indexes in the corresponding cases of MVE-based method and Detonation position-based method,which can improve the efficiency of attitude *** are conducted for different scenarios to verify the feasibility and effectiveness of the proposed method.

关键词： Aircraft vulnerability Attitude selection BP-ANN Damage probability Damage effectiveness

Effective assignment of positional isomers in dimeric shikonin and its analogs by ^(1)H NMR spectroscopy

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Chinese Chemical Letters 2024年第5期35卷 223-226页

作者： ling-Hao Zhao Hai-Wei Yan Jian-Shuang Jiang Xu Zhang Xiang Yuan Ya-Nan yang pei-Cheng Zhang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

An approach for distinguishing two types of positional isomers of dimeric shikonin and its analogs was explored with ^(4)JC,H long-range correlation by prolonging the acquisition time at ^(2,3)JC,H values of 2.0 and ***,the ^(1)H(proton)nuclear magnetic resonance(NMR)pattern of phenolic hydroxyl protons was developed as a“diagnosis signal”to ascertain the relative location of each side chain in DMSO-d_(6) at sample concentrations of 0.022-0.034 mol/*** chemical shift differences of 0.6ppm between OH-5' and OH-1 and between OH-8'and OH-4 are assigned to Type A and Type B,*** reported ambiguous structures were corrected by this ***,the steric structures of isolated compounds were elucidated by quantum chemical calculations of electronic circular dichroism(ECD)spectra.

关键词： Arnebia euchroma Dimeric hydroxyl naphthoquinones Positional isomers ^(1)H NMR spectroscopy Chemical shift difference

Disparity estimation for multi-scale multi-sensor fusion

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Journal of Systems Engineering and Electronics 2024年第2期35卷 259-274页

作者： SUN Guoliang pei Shanshan LONG Qian ZHENG Sifa yang Rui Suzhou Automotive Research Institute Tsinghua UniversitySuzhou 215000China Beijing Smarter Eye Technology Co. Ltd.Beijing 100023China College of Artifical Intelligence Tianjin University of Science and TechnologyTianjin 300457China State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China Department of Precision Instrument Tsinghua UniversityBeijing 100084China

The perception module of advanced driver assistance systems plays a vital *** schemes often use a single sensor for data processing and environmental perception or adopt the information processing results of various sensors for the fusion of the detection *** paper proposes a multi-scale and multi-sensor data fusion strategy in the front end of perception and accomplishes a multi-sensor function disparity map generation scheme.A binocular stereo vision sensor composed of two cameras and a light deterction and ranging(LiDAR)sensor is used to jointly perceive the environment,and a multi-scale fusion scheme is employed to improve the accuracy of the disparity *** solution not only has the advantages of dense perception of binocular stereo vision sensors but also considers the perception accuracy of LiDAR *** demonstrate that the multi-scale multi-sensor scheme proposed in this paper significantly improves disparity map estimation.

关键词： stereo vision light deterction and ranging(LiDAR) multi-sensor fusion multi-scale fusion disparity map