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Highlights of special issue on “Sustainable Phosphorus Use in Agri-Food System”

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Frontiers of Agricultural Science and Engineering 2019年第4期6卷 311-312页

作者： Hans LAMBERS Lixing YUAN xuejun liu National Academy of Agriculture Green Development College of Resources and Environmental SciencesChina Agricultural UniversityBeijing 100193China School of Biological Science University of Western AustraliaPerthWA 6009Australia

Phosphorus(P)is an essential element for plants,and all other life on Earth including ***,P is a nonrenewable resource with a very uneven distribution in the *** the agri-food system,P is supplied to agricultural land as chemical P fertilizer and/or animal manure for producing food,feed and fiber,followed by their use or consumption by animals and *** some returns of P in crop production as organic manure,large amounts of P are released into the environment,severely contributing to pollution or eutrophication(mainly surface waters like rivers,lakes and oceans).Therefore,how to close the P cycle in the agri-food system has become a major challenge for ensuring food and environmental security *** special issue focuses on the sustainable use of P in agriculture,and comprises 12 review and research articles covering a wide range of topics on P resources,P use in crop and animal systems,P recycling and eco-environment.

关键词： manure globally spite

Carbon matrix/SiNWs heterogeneous block as improved reversible anodes material for lithium ion batteries

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Journal of Energy Chemistry 2014年第1期23卷 105-110页

作者： Yao Wang Long Ren Yundan liu xuejun liu Kai Huang Xiaolin Wei Jun Li Xiang Qi Jianxin Zhong Hunan Key Laboratory for Micro-Nano Energy Materials and Devices Xiangtan University Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics Xiangtan University

A novel carbon matrix/silicon nanowires(SiNWs) heterogeneous block was successfully produced by dispersing SiNWs into templated carbon matrix via a modified evaporation induced self-assembly method. The heterogeneous block was determined by X-ray diffraction, Raman spectra and scanning electron microscopy. As an anode material for lithium batteries, the block was investigated by cyclic voltammograms(CV), charge/discharge tests, galvanostatic cycling performance and A. C. impedance spectroscopy. We show that the SiNWs disperse into the framework, and are nicely wrapped by the carbon matrix. The heterogeneous block exhibits superior electrochemical reversibility with a high specific capacity of 529.3 mAh/g in comparison with bare SiNWs anode with merely about 52.6 mAh/g capacity retention. The block presents excellent cycle stability and capacity retention which can be attributed to the improvement of conductivity by the existence of carbon matrix and the enhancement of ability to relieve the large volume expansion of SiNWs during the lithium insertion/extraction cycle. The results indicate that the as-prepared carbon matrix/SiNWs heterogeneous block can be an attractive and potential anode material for lithium-ion battery applications.

关键词： SiNWs carbon matrix heterogeneous block lithium-ion battery

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电磁-液压复合防抱死制动系统滑模控制

农业机械学报 2014年第5期45卷 1-7页

作者：刘学军何仁江苏大学汽车与交通工程学院镇江212013 广西交通职业技术学院南宁530023

为了提高电磁-液压复合制动系统的紧急制动性能,设计了一套既适用于电磁制动特性,又适用于液压制动特性的电磁-液压复合制动系统,按系统结构建立了液压制动系统数学模型,分低速区和高速区分别建立了电磁制动数学模型。在1/4车辆模型受... 详细信息

为了提高电磁-液压复合制动系统的紧急制动性能,设计了一套既适用于电磁制动特性,又适用于液压制动特性的电磁-液压复合制动系统,按系统结构建立了液压制动系统数学模型,分低速区和高速区分别建立了电磁制动数学模型。在1/4车辆模型受力分析的基础上,设计了滑模变结构控制器,搭建了硬件在环仿真平台,模拟沥青路面和冰雪路面进行了防抱死制动系统(ABS)性能仿真实验,并同商业ABS在同等条件下的实验结果进行了对比分析。实验结果表明:电磁-液压复合制动系统相比传统液压制动系统而言,响应速度更快,滑移率控制更精确,车辆制动稳定性更高,制动时间也有小幅减少,同时还减小了机械磨损,并降低了热衰退和失效的风险。

关键词：复合制动系统液压电磁滑模控制硬件在环仿真

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

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Advances in Atmospheric Sciences 2020年第9期37卷 933-938页

作者： Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan liu Linlin SONG Shili TIAN Xuemei LÜ Yang SUN Tao SONG Wendell WWALTERS xuejun liu Nicholas AMARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Urban Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Key Laboratory of Geographic Information Sciences Ministry of EducationSchool of Geographic SciencesEast China Normal UniversityShanghai 200241China CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Department of Earth Environmentaland Planetary SciencesBrown UniversityProvidenceRI 02912USA Institute at Brown for Environment and Society Brown UniversityProvidenceRI 02912USA College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193China National Physical Laboratory Air Quality and Aerosol Metrology GroupEnvironment DepartmentHampton RoadTeddingtonMiddlesexTW110LWUK National Satellite Meteorological Center China Meteorological AdministrationBeijing100081China Key Laboratory of Stable Isotope Techniques and Applications Shenyang 110016China Centre for Environmental and Agricultural Informatics Cranfield UniversityCollege RoadMK430ALUK

While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly,aerosol ammonium nitrate remains high in East *** the high nitrate abundances are strongly linked with ammonia,reducing ammonia emissions is becoming increasingly important to improve the air quality of *** satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions,long-term surface observation of ammonia concentrations are *** addition,there is still no consensus on whether agricultural or non-agricultural emissions dominate the urban ammonia *** the ammonia source by nitrogen isotope helps in designing a mitigation strategy for policymakers,but existing methods have not been well *** the concentration measurements and identifying source apportionment of atmospheric ammonia is thus an essential step towards reducing ammonia emissions.

关键词： ammonia nitrate Ammonia

CLIMATE-CHANGE-INDUCED TEMPORAL VARIATION IN PRECIPITATION INCREASES NITROGEN LOSSES FROM INTENSIVE CROPPING SYSTEMS: ANALYSIS WITH A TOY MODEL

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Frontiers of Agricultural Science and Engineering 2022年第3期9卷 457-464页

作者： Peter MVITOUSEK Xinping CHEN Zhenling CUI xuejun liu Pamela AMATSON Ivan ORTIZ-MONASTERIO GPhilip ROBERTSON Fusuo ZHANG Department of Biology Stanford UniversityStanfordCA 94305USA College of Resources and Environment and Academy of Agricultural SciencesSouthwest UniversityChongqing 400716China College of Resources&Environmental Sciences China Agricultural UniversityBeijing 100193China Department of Earth System Science Stanford UniversityStanfordCA 94305USA International Maize and Wheat Improvement Center(CIMMYT) El BatanTexcoco 56237Mexico W.K.Kellogg Biological Station and Department of PlantSoil and Microbial SciencesMichigan State UniversityHickory CornersMI 49060USA.

A simple‘toy’model of productivity and nitrogen and phosphorus cycling was used to evaluate how the increasing temporal variation in precipitation that is predicted(and observed)to occur as a consequence of greenhouse-gasinduced climate change will affect crop yields and losses of reactive N that can cause environmental damage and affect human *** model predicted that as temporal variability in precipitation increased it progressively reduced yields and increased losses of reactive N by disrupting the synchrony between N supply and plant N ***,increases in the temporal variation of precipitation increased the frequency of floods and *** of this model indicate that climate-change-driven increases in temporal variation in precipitation in rainfed agricultural ecosystems will make it difficult to sustain cropping systems that are both high-yielding and have small environmental and human-health footprints.

关键词： crop yield fertilizer timing nitrogen loss precipitation variability toy model

Acoustic wave detection of laser shock peening

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Opto-Electronic Advances 2018年第9期1卷 11-15页

作者： Jiajun Wu Jibin Zhao Hongchao Qiao xuejun liu Yinuo Zhang Taiyou Hu Manufacturing Technology Department Shenyang Institute of Automation Chinese Academy of Sciences Shenyang 110016 China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang 110016 China School of Engineering Sciences University of Chinese Academy of Sciences Beijing 100049 China School of Computer Hunan University of Technology Zhuzhou 412007 China

In order to overcome the existing disadvantages of offline laser shock peening detection methods, an online detection method based on acoustic wave signals energy is provided. During the laser shock peening, an acoustic emission sen- sor at a defined position is used to collect the acoustic wave signals that propagate in the air. The acoustic wave signal is sampled, stored, digitally filtered and analyzed by the online laser shock peening detection system. Then the system gets the acoustic wave signal energy to measure the quality of the laser shock peening by establishing the correspondence between the acoustic wave signal energy and the laser pulse energy. The surface residual stresses of the samples are measured by X-ray stress analysis instrument to verify the reliability. The results show that both the surface residual stress and acoustic wave signal energy are increased with the laser pulse energy, and their growth trends are consistent. Finally, the empirical formula between the surface residual stress and the acoustic wave signal energy is established by the cubic equation fitting, which will provide a theoretical basis for the real-time online detection of laser shock peening.

关键词： laser shock peening acoustic wave laser pulse energy surface residual stress acoustic wave signal energy online detection

Analysis and experimentation of key technologies in service-oriented optical internet

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Science China(Information Sciences) 2011年第2期54卷 215-226页

作者： JI YueFeng, REN DanPing, LI Hui, liu xuejun & WANG ZhengZhong Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing 100876, China Key Laboratory of Information Photonics and Optical Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing China

To satisfy diverse bandwidth-intensive applications envisioned in the internet of the future, research on a distributed optical internet, enabling efficient utilization of geographically distributed resources, has become attractive. The deployment of such a network, however, has its own technical challenges, including network architecture, resource management, and high-speed transmission. To address these issues, a service-oriented-architecture-based distributed optical internet architecture is proposed. Thereafter, key technologies of an optical internet, such as optical multicasting, distributed resource control, and high-speed transmission, are analyzed and investigated. The proposed schemes are verified through experimentation and simulation.

关键词： optical internet service-oriented distributed optical networks optical multicasting optical transmission

Nutrients and Trace Elements in a Pig Farm in Beijing： Chinese and German Recommendations

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Journal of Agricultural Science and Technology(A) 2012年第2期2卷 191-208页

作者： Roxana Mendoza Huaitalla Eva Gallmann xuejun liu Eberhard Hartung Institute of Agricultural Engineering University of Hohenheim Stuttgart 70599 Germany College of Resources and Environmental Sciences China Agricultural University Beo＇ing 100094 China Institute of Agricultural Engineering Christian-Albrechts-University Kiel Kie124098 Germany

Emergence of Chinese economy together with the current Livestock Revolution in Asia have led to an increase of meat demands, specially pork that is reflected in the growth of commercial pig farms in peri-urban areas of Beijing, capital of People＇s Republic of China. In the framework of the International Research Training Group and of the Sino-Project Recycling of Organic Residues from Agricultural and Municipal Origin in China, the status quo of a large pig farm is researched. The first phase of the project was focused on a detailed description of the nutrients and trace elements contained in the main inputs （water, feed） and outputs （manure, wastewater） of the pig farm. The compliance with the Chinese national standards or often referred to as GB standards （in Chinese ＂GuoBiao＂） and, current German recommendations were included. The analysis of nutrients and trace minerals followed the natural structure of the pig life cycle, i.e., gestation, farrowing, weaning and fattening. The main results showed that the pig drinking water met the recommendations for livestock drinking water, ground water and human drinking water. Concentrations of Zn, Cu, Mn and As in the pig feeds samples displayed higher values compared to the Chinese and German recommendations. Average values of trace elements in the pig manure did not surpass the Chinese and German recommendations of biowastes, however, some manure samples showed excessive concentrations of Cd, Cu and Zn. Likewise, Pb, Cd, Cr, Cu and Zn concentrations in the wastewater surpassed the recommendations for irrigation water.

关键词： Nutrients trace minerals pig farm Chinese standard.

AGRICULTURAL GREEN DEVELOPMENT TO ACHIEVE FOOD SECURITY AND CARBON REDUCTION IN THE CONTEXT OF CHINA'S DUAL CARBON GOALS

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Frontiers of Agricultural Science and Engineering 2023年第2期10卷 262-267页

作者： Yulong YIN Kai HE Zhong CHEN Yangyang LI Fengling REN Zihan WANG Yingcheng WANG Haiqing GONG Qichao ZHU Jianbo SHEN xuejun liu Zhenling CUI College of Resources and Environmental Sciences National Academy of Agriculture Green DevelopmentKey Laboratory of Plant-Soil Interactions(Ministry of Education)Key Laboratory of Low-carbon Green Agriculture(Ministry of Agriculture and Rural Affairs)China Agricultural UniversityBeijing 100193China

The agricultural sector,a major source of greenhouse gas emissions,and emissions from agriculture must be reduced substantially to achieve carbon(C)*** on a literature analysis and other research results,this study investigated the effects and prospects of C reduction in agricultural systems under different scenarios(i.e.,methods and approaches)in the context of China's dual C goals,as those working in the agricultural sector have yet to reach a consensus on how to move *** views,standards,and countermeasures were analyzed to provide a reference for agricultural action supporting China's C neutrality goal.

关键词： agriculture carbon neutrality carbon peak food security carbon mitigation strategies