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中国居民家庭食物浪费的收入弹性、效应解析及模拟分析

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农业经济问题 2022年第5期43卷 110-123页

作者：张宗利徐志刚南京农业大学经济管理学院南京210095

食物浪费不仅导致食物生产和分销过程浪费大量资源,还增加垃圾处理压力和温室气体排放,挑战粮食安全。通过理论与实证研究解析了收入增长影响家庭食物浪费的数量效应和结构效应。基于中国健康与营养调查数据的实证结果显示,收入增长会... 详细信息

食物浪费不仅导致食物生产和分销过程浪费大量资源,还增加垃圾处理压力和温室气体排放,挑战粮食安全。通过理论与实证研究解析了收入增长影响家庭食物浪费的数量效应和结构效应。基于中国健康与营养调查数据的实证结果显示,收入增长会显著提高居民家庭食物浪费量,食物浪费收入弹性为0.26,其中,数量效应表现为收入增长提高谷物类、蔬菜类和肉蛋奶类食物的浪费量,包括通过提高家庭食物浪费率对食物浪费量产生影响;结构效应表现为收入增长降低蔬菜类食物浪费量占比,提高肉蛋奶类食物浪费量占比,但对谷物类食物浪费量占比无显著影响。进一步分析发现收入增长与家庭食物浪费量之间存在非线性关系。两种方案的模拟结果均显示,2030年前我国人均食物浪费量和食物浪费总量仍会继续上升,有必要制定和实施遏制居民家庭食物浪费的具体干预措施。城乡之间存在明显差异,收入增长对农村居民家庭食物浪费的作用更强,因此干预措施制定应着重关注农村地区家庭食物浪费问题。

关键词：食物浪费收入弹性数量效应结构效应模拟预测

外包与流转:作业服务规模化是否延缓农地经营规模化——基于要素约束缓解与地租上涨的视角

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中国农村观察 2022年第2期 19-38页

作者：章丹徐志刚刘家成南京农业大学经济管理学院金善宝农业现代化发展研究院南京财经大学财政与税务学院

理论上,农业生产环节作业外包服务的要素约束缓解效应会延缓小农户转出农地,但中国农业生产环节作业外包服务市场与农地流转市场均稳步发展的现实,并不支持作业服务规模化会替代农地经营规模化的推断。本文基于江苏、四川和吉林3省265... 详细信息

理论上,农业生产环节作业外包服务的要素约束缓解效应会延缓小农户转出农地,但中国农业生产环节作业外包服务市场与农地流转市场均稳步发展的现实,并不支持作业服务规模化会替代农地经营规模化的推断。本文基于江苏、四川和吉林3省265个行政村的3期调查数据,以及来自这些行政村样本农户的2期数据,利用固定效应模型和工具变量法,从村庄农地流转市场和微观农户行为两个层面分析了农业生产环节作业外包服务供给对农地流转的影响。研究发现,作业服务规模化整体上有利于农地经营规模化。农业生产环节作业外包服务发展促使规模经营户增加农地转入、兼业化程度较高的小农户增加农地转出。究其原因,一是农业生产环节作业外包服务供给对规模经营户的要素约束缓解效应比对小农户更明显;二是农业生产环节作业外包服务供给导致农地流转市场供不应求和地租上涨,地租上涨效应对兼业化程度较高的小农户比对兼业化程度较低的小农户更明显。

关键词：外包服务农地流转要素约束缓解效应地租上涨效应

Mapping super-resolution image quality

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Light(Science & Applications) 2024年第2期13卷 178-180页

作者： Megan A.Steves Ke xu Department of Chemistry University of CaliforniaBerkeleyCA94720USA

The local quality of super-resolution microscopy images can be assessed and mapped by rolling Fourier ring correlation,even when image quality varies within a single image.

关键词： image resolution Mapping

Controllable chemical redox reactions to couple microbial degradation for organic contaminated sites remediation:A review

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Journal of Environmental Sciences 2024年第5期139卷 428-445页

作者： Bin Chen Jiang xu Lizhong Zhu College of Environmental and Resource Sciences Zhejiang UniversityHangzhou 310058China Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control Zhejiang UniversityHangzhou 310058China Zhejiang Agriculture&Forest University Lin'an 311300China

Global environmental concern over organic contaminated sites has been progressively conspicuous during the process of urbanization and industrial restructuring.While traditional physical or chemical remediation technologies may significantly destroy the soil structure and function,coupling moderate chemical degradation with microbial remediation becomes a potential way for the green,economic,and efficient remediation of contaminated sites.Hence,this work systematically elucidates why and how to couple chemical technology with microbial remediation,mainly focused on the controllable redox reactions of organic contaminants.The rational design of materials structure,selective generation of reactive oxygen species,and estimation of degradation pathway are described for chemical oxidation.Meanwhile,current progress on efficient and selective reductions of organic contaminants(i.e.,dechlorination,defluorination,-NO_(2) reduction)is introduced.Combined with the microbial remediation of contaminated sites,several consideration factors of how to couple chemical and microbial remediation are proposed based on both fundamental and practical points of view.This review will advance the understanding and development of chemical-microbial coupled remediation for organic contaminated sites.

关键词： Soil remediation Groundwater remediation Rational design Reactive species Environmental nanotechnology

Bioinspired 3D flexible devices and functional systems

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National Science Review 2024年第3期11卷 271-295页

作者： xu Cheng Zhangming Shen Yihui Zhang Applied Mechanics Laboratory Department of Engineering Mechanics Tsinghua University Laboratory of Flexible Electronics Technology Tsinghua University

Flexible devices and functional systems with elaborated three-dimensional(3D) architectures can endow better mechanical/electrical performances, more design freedom, and unique functionalities, when compared to their two-dimensional(2D) counterparts. Such 3D flexible devices/systems are rapidly evolving in three primary directions, including the miniaturization, the increasingly merged physical/artificial intelligence and the enhanced adaptability and capabilities of heterogeneous integration.Intractable challenges exist in this emerging research area, such as relatively poor controllability in the locomotion of soft robotic systems, mismatch of bioelectronic interfaces, and signal coupling in multi-parameter sensing. By virtue of long-time–optimized materials, structures and processes, natural organisms provide rich sources of inspiration to address these challenges, enabling the design and manufacture of many bioinspired 3D flexible devices/systems. In this Review, we focus on bioinspired 3D flexible devices and functional systems, and summarize their representative design concepts, manufacturing methods, principles of structure-function relationship and broad-ranging applications. Discussions on existing challenges, potential solutions and future opportunities are also provided to usher in further research efforts toward realizing bioinspired 3D flexible devices/systems with precisely programmed shapes,enhanced mechanical/electrical performances, and high-level physical/artificial intelligence.

关键词： bioinspired designs biomimetic 3D structures 3D flexible electronics 3D functional systems direct 3D manufacture 2D-to-3D assembly

Assessment of tree-ring mercury radial translocation and age effect in Masson pine:Implications for historical atmospheric mercury reconstruction

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Journal of Environmental Sciences 2024年第4期138卷 266-276页

作者： xu Liu xun Wang Dingyong Wang College of Resources and Environment Southwest UniversityChongqing 400715China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury(Hg)trends,but with the large knowledge gaps in the reliability.In this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at Mt.Jinyun in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric Hg.Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles.The Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg.We found a distinct age effect that the tree ring of young trees had the higher Hg concentration.Besides,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings.The modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in Chongqing.We finally suggest that in further Hg dendrochemistry,better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

关键词： Masson pine Tree-ring mercury Radial translocation Tree age effect

Malware Evasion Attacks Against IoT and Other Devices: An Empirical Study

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Tsinghua Science and Technology 2024年第1期29卷 127-142页

作者： Yan xu Deqiang Li Qianmu Li Shouhuai xu School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing 210023China Department of Computer Science University of Colorado Colorado SpringsColorado SpringsCO 80918USA

The Internet of Things(loT)has grown rapidly due to artificial intelligence driven edge computing.While enabling many new functions,edge computing devices expand the vulnerability surface and have become the target of malware attacks.Moreover,attackers have used advanced techniques to evade defenses by transforming their malware into functionality-preserving variants.We systematically analyze such evasion attacks and conduct a large-scale empirical study in this paper to evaluate their impact on security.More specifically,we focus on two forms of evasion attacks:obfuscation and adversarial attacks.To the best of our knowledge,this paper is the first to investigate and contrast the two families of evasion attacks systematically.We apply 10 obfuscation attacks and 9 adversarial attacks to 2870 malware examples.The obtained findings are as follows.(1)Commercial Off-The-Shelf(COTS)malware detectors are vulnerable to evasion attacks.(2)Adversarial attacks affect COTS malware detectors slightly more effectively than obfuscated malware examples.(3)Code similarity detection approaches can be affected by obfuscated examples and are barely affected by adversarial attacks.(4)These attacks can preserve the functionality of original malware examples.

关键词： Android malware obfuscation adversarial examples

Twisted Integration of Complex Oxide Magnetoelectric Heterostructures via Water‑Etching and Transfer Process

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Nano-Micro Letters 2024年第1期16卷 360-369页

作者： Guannan Yang Guohua Dong Butong Zhang xu xu Yanan Zhao Zhongqiang Hu Ming Liu State Key Laboratory for Manufacturing Systems Engineering Electronic Materials Research LaboratoryKey Laboratory of the Ministry of EducationEngineering Research Center of Spin Quantum Sensor ChipsUniversities of Shaanxi ProvinceSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China

Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering.In recent years,lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations.Moreover,twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures.A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process,which could provide some insight in to the physical phenomena.In this work,the La_(0.67)Sr_(0.33)MnO_(3)(001)/0.7Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.3PbTiO_(3)(011)(LSMO/PMN-PT)heterostructures with 45.and 0.twist angles were assembled via water-etching and transfer process.The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO.A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO[110]easy axis is observed for the 45°Sample by applying a 7.2 kV cm^(−1)electrical field,significantly different from a uniaxial anisotropy with LSMO[100]easy axis for the 0°Sample.The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45°twist angle causes different lattice distortion of LSMO,thereby enhancing both the fourfold and uniaxial anisotropy.This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures.

关键词： Magnetoelectric heterostructures Twist angle Epitaxial lift-off Magnetic anisotropy Ferromagnetic resonance

农业生产机械服务是否延缓了小农户土地转出?

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农林经济管理学报 2023年第5期22卷 662-670页

作者：朱玮强高群徐志刚南京农业大学经济管理学院江苏南京210095

基于黑龙江、浙江、河南和四川四省512户小农户调查数据,采用OLS模型分析农业生产机械服务对小农户土地转出的影响及异质性。结果表明:1)农业生产机械服务缓解小农户土地经营的要素约束效应不明显,相反,其推高地租并促进小农户土地转出... 详细信息

基于黑龙江、浙江、河南和四川四省512户小农户调查数据,采用OLS模型分析农业生产机械服务对小农户土地转出的影响及异质性。结果表明:1)农业生产机械服务缓解小农户土地经营的要素约束效应不明显,相反,其推高地租并促进小农户土地转出效应显著;2)要素约束缓解效应不明显主要源于额外且确定的机械服务费用和不明显的要素减量和效率提升;3)异质性结果显示,农业生产机械服务要素约束缓解效应因小农户劳动力女性化程度提高而强化,不因劳动力老龄化程度提高而变化。据此,建议进一步推进农业生产机械服务发展,针对不同类型农户提供差异性服务,丰富服务内容,提升服务质量,完善配套政策,促进农业生产规模化发展。

关键词：农业生产机械服务土地转出要素约束缓解效应地租上涨效应劳动力禀赋异质