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Facet-dependent transformation and toxicity of nanoscale zinc oxide in the synthetic saliva

Journal of Environmental Sciences 2024年第5期139卷 170-181页

作者： Xiang Zhang Yunpeng huang jikun Wang Jie Tang YangMei Nali Zhu Zhigang Li Lingxiangyu Li YaweiWang School of Environment Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Key Laboratory of Systems Health Science of Zhejiang Province Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Department of Chemistry University of PennsylvaniaPhiladelphia 19104USA

The nanoscale zinc oxide(n-ZnO)was used in food packages due to its superior antibac terial activity,resulting in potential intake of n-ZnO through the digestive system,wherein n-ZnO interacted with saliva.In recent,facet engineering,a technique for controlling the exposed facets,was applied to n-ZnO,whereas risk of n-ZnO with specific exposed facets in saliva was ignored.ZnO nanoflakes(ZnO-0001)and nanoneedles(ZnO-1010)with the pri mary exposed facets of{0001}and{1010}respectively were prepared in this study,investigat ing stability and toxicity of ZnO-0001 and ZnO-1010 in synthetic saliva.Both ZnO-0001 and ZnO-1010 partially transformed into amorphous Zn_(3)(PO_(4))_(2)within 1 hr in the saliva even containing orgnaic components,forming a ZnO-Zn_(3)(PO_(4))_(2)core-shell structure.Neverthe less,ZnO-1010 relative to ZnO-0001 would likely transform into Zn_(3)(PO_(4))_(2),being attributed to superior dissolution of{1010}facet due to its lower vacancy formation energy(1.15 eV than{0001}facet(3.90 eV)).The toxicity of n-ZnO to Caco-2 cells was also dependent on the primary exposed facet;ZnO-0001 caused cell toxicity through oxidative stress,whereas ZnO-1010 resulted in lower cells viability than ZnO-0001 through oxidative stress and mem brane damage.Density functional theory calculations illustrated that·O_(2)^(-)was formed and released on{1010}facet,yet O_(2)^(2-)instead of·O_(2)^(-)was generated on{0001}facet,leading to low oxidative stress from ZnO-0001.All findings demonstrated that stability and toxicity of n-ZnO were dependent on the primary exposed facet,improving our understanding o health risk of nanomaterials.

关键词： The exposed facet Nanoscale ZnO Chemical transformation Synthetic salica Nanotoxicity

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China's Rural Transformation and Policies:Past Experience and Future Directions

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Engineering 2022年第11期18卷 21-26页

作者： jikun huang China Center for Agricultural Policy School of Advanced Agricultural SciencesPeking UniversityBeijing 100087China

1.Introduction China’s rural areas have experienced a significant transformation in the past four decades.During the period 1978-2019,agricultural production increased at an average rate of 5.4%per year[1].Although China’s water availability per capita is only one fourth of the global average and the nation’s cultivated land is only9%of the global total,China’s increased agricultural production has largely met the food needs of one fifth of the world’s population[2].

关键词： Rural Transformation agricultural

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The economic value of grassland ecosystem services: A global meta-analysis

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Grassland Research 2022年第1期1卷 63-74页

作者： Huifang Liu Lingling Hou Nannan Kang Zhibiao Nan jikun huang State Key Laboratory of Grassland Agro-ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhouChina China Center for Agricultural Policy(CCAP) School of Advanced Agricultural SciencesPeking UniversityBeijingChina

Background:Grasslands provide a wide variety of ecosystem services that contribute to human wellbeing.While an increasing number of studies are evaluating the monetary value of grassland ecosystem services,most of them focus on specific grassland ecosystem services at regional or local scales,and they use different assessment methods.Methods:This paper provides a comprehensive assessment of the economic value of global grassland ecosystem services based on a meta-analysis of 702 observations from 134 primary studies.Results:The economic values of different ecosystem services cover a wide range of grassland types,regions,and estimation methods.The annual economic value per hectare ranges from$3955 for semidesert grasslands to$5466 for tropical grasslands.On average,regulating services have the highest value,which is approximately four times that of provisioning services or approximately eight times that of food supply services.Several factors impact the estimated ecosystem service values,including the evaluation method,source and year of publication,and study site.The results indicate that the annual economic value of global grasslands exceeds$20.8 trillion.Conclusions:The findings of this study not only provide useful information for understanding the economic value of various ecosystem services associated with different types of grasslands but also have important policy implications for the ecological conservation of grassland globally.

关键词： ecosystem services economic value grassland screening criteria systematic literature review

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Genetically modified(GM)rice versus non-GM rice:Pesticide use and yield

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Science China(Life Sciences) 2020年第5期63卷 785-787页

作者： Fangbin Qiao Ruifa Hu jikun huang China Economics and Management Academy Central University of Finance and EconomicsBeijing 100081China School of Management and Economics Beijing Institute of TechnologyBeijing 100081China School of Economics and Management Jiangxi Agricultural UniversityNanchang 330045China School of Advanced Agricultural Sciences Peking UniversityBeijing 100089China

Dear Editor,The economic benefits of genetically modified(GM)crops have been well-documented in the literature(huang et al.,2002;huang et al.,2005;Qiao,2015;Qiao et al.,2016).Previous studies showed that the global economic gain that the GM crops had generated at the farm level approximated 100 billion USD in 1996-2011(Brookes and Barfoot,2013).More importantly,this significant benefit had helped dozens of millions of farmers,with most of them being small poor farmers in developing countries.Given their high profitability and other benefits,GM crops had been widely adopted in the world.By 2015,the cumulative sown area for GM crops reached 2 billion hm2,with GM crops being grown in 28 countries(James,2015).

关键词： crops modified Pesticide

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数字技术促进农业农村发展:机遇、挑战和推进思路

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中国农村经济 2024年第1期 21-40页

作者：黄季焜苏岚岚王悦北京大学现代农业研究院北京大学现代农学院中国农业政策研究中心中国社会科学院农村发展研究所

理论上,数字技术在农业农村发展各领域都有潜在的重要作用,但相关实际进展与成效如何以及未来如何推进还缺乏系统的研究。本文的研究目的是厘清数字技术促进农业农村发展的机遇、面临的挑战和发展经验,探索未来发展思路和相关推进措施... 详细信息

理论上,数字技术在农业农村发展各领域都有潜在的重要作用,但相关实际进展与成效如何以及未来如何推进还缺乏系统的研究。本文的研究目的是厘清数字技术促进农业农村发展的机遇、面临的挑战和发展经验,探索未来发展思路和相关推进措施。分析表明:各级政府、农业企业、互联网企业和金融机构都高度重视以数字技术促进农业农村发展,并积极开展试点示范与应用;推进智慧农业和数字乡村建设需分清当前、近期和中长期各应用场景的发展路线图,否则事倍功半;许多应用场景面临需求导向、顶层设计、技术创新、成本收益、数字鸿沟和农民受益等诸多挑战。基于以上分析,本文总结了智慧农业与数字乡村发展的必要条件和充分条件,并提出数字技术促进农业农村发展的思路和政策启示。

关键词：农业农村发展数字技术智慧农业数字乡村数字鸿沟

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China's Labor Transition and the Future of China's Rural Wages and Employment

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China & World Economy 2013年第3期21卷 4-24页

作者： Qiang Li jikun huang Renfu Luo Chengfang Liu Beijing Forestry University Center for Chinese Agricultural Policy Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of Sciences

This paper contributes to the assessment of China＇s rural labor markets. According to our data, the increase in off-farm employment that China experienced during the 1980s and 1990s continued during the 2000s. Our analysis shows that migration has become the most prevalent off-farm activity, although the destination of migrants is shifting from outside of one＇s province to destinations closer to home. The present paperfinds that large shares of male and female individuals, especially those under 40 years, are working off the farm. These findings represent an important contribution to the labor economics field. First, the results of the present paper reveal that the labor transition from the agricultural sector to the non-agricultural sector for key segments of China＇s rural labor force is nearly complete. Second, although a large share of China ＂s rural labor force work in agriculture, most of these workers are older men and women （and likely would not be willing to take low-wage, labor-intensive jobs）. Third, the rising unskilled wage rate in China is partially a result of the tightening of the labor force in the young age cohorts. Finally, due to factors associated with the one child policy and other demographic transition forces, successive age cohorts will continue to fall in absolute number in the coming decade. Assuming China＇s growth continues, we expect to see further wage increases since it will take higher wages to coax more workers to work off the farm.

关键词： China labor force participation rural wages

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Impact of China-ASEAN Free Trade Area on China's International Agricultural Trade and Its Regional Development

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China & World Economy 2007年第5期15卷 77-90页

作者： huanguang Qiu Yang Jun jikun huang Ruijian Chen Associate professor Center for Chinese Agricultural Policy Chinese Academy of Sciences Beijing China Professor Center for Chinese Agricultural Policy Chinese Academy of Sciences Beijing China Ph. D candidate Center for Chinese Agricultural Policy Chinese Academy of Sciences Beijing China

This study aims to examine the impact of the China-ASEAN Free Trade Area （CAFTA） on China＇s international agricultural trade and its regional agricultural development, using the Global Trade Analysis Project model and the China Agricultural Decision Support System. Our analysis showed that：（i） CAFTA will improve resource allocation efficiencies for both China and ASEAN and will promote bilateral agricultural trade and, hence, will have positive effects on the economic development of both sides; （ii） CAFTA will accelerate China＇s export of the agricultural commodities in which it has comparative advantages, such as vegetables, wheat and horticultural products, but at the same time bring about a large increase in imports of commodities such as vegetable oil and sugar; and （iii） CAFTA will have significantly varying impacts on China＇s regional agricultural development because of large differences in the agricultural production structure in each region. Our results indicate that agriculture in the northern, northeastern and eastern regions of China will benefit from CAFTA, whereas agriculture development in southern China will suffer. Those regional specific impacts are quite different from the effects brought by multilateral free trade treaties, such as those of the WTO, which usually have positive effects on south China but negative impacts on the northern and western parts of China.

关键词： free trade area agricultural trade regional development model analysis

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Gender and Off-farm Employment： Evidence from Rural China

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China & World Economy 2016年第3期24卷 18-36页

作者： Xiaobing Wang Linghui Han jikun huang Linxiu Zhang Scott Rozelle Associate Professor School of Advanced Agricultural Sciences Peking University China. Researcher Research Institute of Fiscal Science Ministry of Finance and the National Institute for Fiscal Studies Tsinghua University China Professor School of Advanced Agricultural Sciences Peking University China Professor Center for Chinese Agricultural Policy Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences China Professor Freeman Spogli Institute for International Studies Stanford University USA

The goal of the present paper is to examine how the expansion of the economy from 2000 has affected rural off-farm labor market participation. Specifically, we seek to determine whether off-farm labor increased after 2000, what forms of employment are driving trends in off-farm labor and whether gender differences can be observed in off- farm employment trends. Using a nationally representative dataset that consist of two waves of surveys conducted in 2000 and 2008 in six provinces, this paper finds that off- farm labor market participation continued to rise steadily in the early 2000s. However, there is a clear difference in the trends associated with occupational choice before and after 2000. In addition, we find that rural oy^farm employment trends are diffbrent for men and women. Our analysis also shows that the rise of wage-earning employment corresponds with an increasing unskilled wage for both men and women.

关键词： gender rural China self-employment wages

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A dual-route optical emission spectroscopy diagnostic with wide spectral range and high wavelength resolution on HL-2A tokamak

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Plasma Science and Technology 2024年第3期26卷 25-30页

作者：陈越高继昆龙婷聂林高金明马尧黄渊田文静刘延民朱晓东庄革钟武律许敏 School of Physical Sciences School of Nuclear Sciences and TechnologyUniversity of Science and Technology of ChinaHefei 230026People's Republic of China Southwestern Institute of Physics Chengdu 610041People's Republic of China Tsinghua University Beijing 100084People's Republic of China

A dual-route optical emission spectroscopy(D-OES)diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2 A tokamak.This diagnostic is composed of an imaging system,a beam-splitting system for dual-route measurements,fiber bundles,a spectrometer system,and a control and acquisition system.One route is used to obtain wide-spectral-range spectra,and the other route is used to acquire high-wavelengthresolution line shapes.The spectral resolution of the wide-range spectrometers is 0.8 nm with a coverage of 800 nm(@200-1000 nm).The spectral resolution of the high-resolution spectrometer is 0.01 nm with a coverage of 6 nm(@200-660 nm).The spatial resolution of each route of D-OES is about 4 cm with 11 channels.The temporal resolution is 16 ms at maximum in the single-channel mode.Wide-range spectra(containing Balmer series and a Fulcher band)and highly resolved Ha line shapes are obtained by D-OES in the hydrogen glow discharge in the lab.D-OES measurements are carried out in the high-density deuterium experiments of HL-2A.The electron density n_(e)and deuterium temperature T_(D) in the X-point multifaceted asymmetric radiation from the edge(MARFE)region are derived simultaneously by fitting the measured D_(a) shape.The density n_(e)is observed to increase from~8.7×10^(18)m^(-3)to~7.8×10^(19)m^(-3),and the temperature T_(D)drops from~14.4 eV to~2.3 eV after the onset of MARFE in the discharge#38260.

关键词： optical emission spectroscopy Balmer series tokamak

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基于区块链技术的农产品质量安全追溯体系:实践、挑战与建议

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农业经济问题 2024年第5期 33-47页

作者：胡雯黄季焜陈富桥饶思航易红梅北京大学现代农学院中国农业政策研究中心北京100871 中国农业科学院茶叶研究所杭州310008

区块链技术具有去中心化和信息难以篡改的技术特征。基于区块链技术的农产品溯源体系能有效激励农产品供应链各主体采取措施保障农产品质量安全。在加速布局追溯体系建设、优化数字化发展的环境下,中国农产品区块链溯源技术迎来重要发... 详细信息

区块链技术具有去中心化和信息难以篡改的技术特征。基于区块链技术的农产品溯源体系能有效激励农产品供应链各主体采取措施保障农产品质量安全。在加速布局追溯体系建设、优化数字化发展的环境下,中国农产品区块链溯源技术迎来重要发展机遇,涌现了一些政府主导的创新实践,但总体而言该技术应用仍处于初级阶段。本文系统地梳理了砀山酥梨、潍坊韭菜、西湖龙井茶三个实践案例,研究发现目前农产品区块链溯源技术应用仍面临溯源成本高、产品溢价难预期、利益分配机制不健全等关键挑战。为促进中国农产品区块链溯源体系建立,本文根据国内外实践经验提出以下建议:实施重点环节溯源以降低成本和优化溯源体系;提供公开透明的公众投诉渠道以提升产品溢价;采用闭环式运作且配套严格的质量安全监管制度。

关键词：区块链技术农产品溯源供应链食品安全实践

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