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No country is an island in regulating food safety:How the WTO monitors Chinese food safety laws through the Trade Policy Review Mechanism(TPRM)

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Journal of Integrative Agriculture 2015年第11期14卷 2142-2156页

作者： Francis Snyder Northwest A&F university school of Transnational Law Peking University Shenzhen Graduate School College of Europe

Established within the framework of the World Trade Organization （WTO）, the Trade Policy Review Mechanism （TPRM） reviews periodically the trade policies of all WTO Members. The review includes many aspects of food safety regulation. china＇s trade policy is reviewed every two years. This paper analyses in detail the reviews of china＇s trade policy in 2006, 2008, 2010, 2012 and 2014. It focuses in particular on food safety laws and types of standards, alignment of domestic standards with international standards, the role of different domestic institutions, transparency and notification of food safety measures under the WTO agreements on Sanitary and Phytosanitary Measures （SPS） and on Technical Barriers to Trade （TBTAgreement）, import and export, and geographical indications （GIs）. It concludes that the WTO TPRM can contribute, within its mandate, to reform of Chinese food safety laws and improvement of food safety in china. it notes that china has already undertaken substantial reforms of its system for regulating food safety. It recommends that china should continue to participate actively in the TPRM, follow its own path with regard to alignment and learn selectively from other WTO Members.

关键词： food safety food standards public health consumer welfare china Chinese food safety laws World Trade Organization WTO law Trade Policy Review Mechanism (TPRM) SPS Agreement TBT Agreement

Influence of supports on photocatalytic degradation of phenol and 4-chlorophenol in aqueous suspensions of titanium dioxide

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Journal of Environmental Sciences 2013年第2期25卷 399-404页

作者： Kashif Naeem Feng Ouyang Central Analytical Facility Division Pakistan Institute of Nuclear Science and Technology Environmental Science and Engineering Research Center Harbin Institute of Technology Shenzhen Graduate School

The photocatalytic degradation of phenol and 4-chlorophenol （4-CP） in aqueous suspensions with the use of titanium dioxide （TiO2 ） under UV irradiation was examined. The effects of different supporting materials mixed physically with TiO2 were studied to achieve maximum degradation efficiency. Among the three supports, namely activated carbon （AC）, silica （SiO2 ） and zeolite （ZSM-5）, all exhibited paramount efficiency for degradation of phenol and 4-CP and was better than TiO2 alone. The optimum concentration was found to be 50 mg for all supporting materials. The efficiency order of the three supports was as follows： AC 〉 ZSM-5 〉 SiO2 , respectively. Whilst, the degradation of phenol and 4-CP was improved from 70.6% to 87.6% and 80.6% to 89.7%, respectively, within 120 min photocatalysis in the presence of optimal amount of AC. The degradation was also comparatively enhanced in the presence of cheaper rice husk and the activity was closed to ZSM-5 and lower than AC.

关键词： 4-chlorophenol phenol photocatalytic degradation support TiO2

基于石墨烯和回收金制备便携式、可清洗太阳能蒸发器及其高效即时水净化研究（英文）

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Science china Materials 2024年

作者：李飞黄炯鹏胥丁心王程锦赵亮龚新渝李航张灿阳宋清华苏阳成会明 Tsinghua-Berkeley shenzhen Institute&Institute of Materials Research&Institute of Biopharmaceutical and Health Engineering Tsinghua Shenzhen International Graduate SchoolTsinghua University shenzhen Key Laboratory of Energy Materials for Carbon Neutrality Institute of Technology for Carbon NeutralityShenzhen Institute of Advanced TechnologyChinese Academy of Sciences Faculty of Materials Science and Energy Engineering Shenzhen University of Advanced Technology Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

太阳能蒸发器为应对全球淡水短缺问题,提供了一种可持续且高效的水净化解决方案.尽管此前的研究在最大化水蒸发速率方面取得了显著进展,但尚无单一蒸发器具备实际应用所需的所有特性,如生成饮用水的高效性、用于现场水净化的优异便携性...

太阳能蒸发器为应对全球淡水短缺问题,提供了一种可持续且高效的水净化解决方案.尽管此前的研究在最大化水蒸发速率方面取得了显著进展,但尚无单一蒸发器具备实际应用所需的所有特性,如生成饮用水的高效性、用于现场水净化的优异便携性、减少蒸发器结垢的良好可清洗性,以及良好的可重复使用性.本文提出了一种用于即时水净化的高性能光热材料制备策略.通过在具有优异机械性能的海绵中同时引入石墨烯和从电子垃圾中提取的金颗粒,实现了高效水净化.在一个太阳光强度照射下水蒸发速率达到3.55 kg/m2/h,这得益于对石墨烯原子结构的控制以及金纳米颗粒尺寸依赖性表面等离子体共振效应.此外,该材料便携性强,可折叠、可真空压缩、干燥、再使用而不影响性能,且可以通过反复清洗去除污染物结垢,从而实现重复使用.研究表明该蒸发器可以将多种类型的污染水转化为可饮用的清洁水,并且可以任意角度安装,便于追踪太阳入射角,实现太阳光的高效利用.所组装的蒸发器在户外阳光下的水蒸发速率高达9.36 kg/m2/h,所产出的净化水符合世界卫生组织的饮用水标准.

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Matching user identities across social networks with limited profile data

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Frontiers of Computer Science 2020年第6期14卷 171-184页

作者： Ildar NURGALIEV Qiang QU Seyed Mojtaba Hosseini BAMAKAN Muhammad MUZAMMAL shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen 518055China Sberbank Moscow 121170Russia Department of Management Yazd UniversityYazd 89195-741Iran Department of Computer Science Bahria UniversityIslamabad 44000Pakistan

Privacy preservation is a primary concern in social networks which employ a variety of privacy preservations mechanisms to preserve and protect sensitive user information including age,location,education,interests,and *** task of matching user identities across different social networks is considered a challenging *** this work,we propose an algorithm to reveal user identities as a set of linked accounts from different social networks using limited user profile data,i.e,user-name and ***,we propose a framework,ExpandUIL,that includes three standalone al-gorithms based on(i)the percolation graph matching in Ex-pand FullName algorithm,(i)a supervised machine learning algorithm that works with the graph embedding,and(ii)a combination of the two,ExpandUserLinkage *** proposed framework as a set of algorithms is significant as,(i)it is based on the network topology and requires only name feature of the nodes,(i)it requires a considerably low initial seed,as low as one initial seed suffices,(ii)it is iterative and scalable with applicability to online incoming stream graphs,and(iv)it has an experimental proof of stability over a real ground-truth *** on real datasets,Instagram and VK social networks,show upto 75%recall for linked ac-counts with 96%accuracy using only one given seed pair.

关键词： social networks user identity linkage graph structure learning,maximum subgraph matching graph percolation

Breaking the energy density limit of Li NiO_(2):Li_(2)NiO_(3)or Li_(2)NiO_(2)?

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Science china Materials 2022年第4期65卷 913-919页

作者： Yining Jia Yaokun Ye Jiahua Liu Shisheng Zheng Weicheng Lin Zhu Wang Shunning Li Feng Pan Jiaxin Zheng school of Advanced Materials Peking UniversityShenzhen Graduate SchoolShenzhen518055China Fujian science&technology innovation laboratory for energy devices of china(21C-LAB) Ningde352100China

The development of next-generation layered oxide cathodes for high-energy-density electrical vehicle Li-ion batteries(LIBs)is an urgent *** existing method is achieved by continuously increasing the Ni contents of Ni-based layered oxides,but it has been limited to LiNiO_(2).To break this limit and attain increased energy densities,a promising strategy,which involves the introduction of excess Li ions into transition metal(TM)layers to form Li-excess compounds Li_(2)MO_(3)(M is a TM cation),has attracted enormous interest ***,another strategy,which has been neglected in recent years,involves the insertion of an extra layer of Li ions between the TM and original Li layers to form Li_(2)MO_(2).In this study,typical reversible Li_(2)NiO_(3) and 1T-Li_(2)NiO_(2) were selected as two representative cathodes to break the limit of LiNiO_(2),thereby availing comprehensive comparison with LiNiO_(2) regarding their overall properties as cathodes from a theoretical ***,dissimilar to the Ni^(3+)/Ni^(4+)monoelectron cationic redox associated with LiNiO_(2),a polaronic anionic redox reaction occurs in Li_(2)NiO_(3),while a reversible Ni^(2+)/Ni^(4+)double-electron redox reaction accompanied by insulator-metal transition occurs in Li_(2)NiO_(2).Owing to this double-electron cationic activity,Li_(2)NiO_(2) exhibits absolute advantages over the other two materials(LiNiO_(2) and Li_(2)NiO_(3))as cathodes for LIBs in terms of the capacity,energy density,electronic conductivity,and thermal stability,thus rendering it the most promising candidate for next-generation layered oxide cathodes with high energy densities to break the limit of LiNiO_(2).

关键词： Li-ion battery Li_(2)NiO_(3)and Li_(2)NiO_(2) double-electron redox anionic redox theoretical perspective

Resilience patterns of human mobility in response to extreme urban floods

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National Science Review 2023年第8期10卷 121-133页

作者： Junqing Tang Pengjun Zhao Zhaoya Gong Hongbo Zhao Fengjue Huang Jiaying Li Zhihe Chen Ling Yu Jun Chen school of Urban Planning and Design Shenzhen Graduate School Peking University 2. Key Laboratory of Earth Surface System and Human-Earth Relations of Ministry of Natural Resources of China Shenzhen Graduate SchoolPeking University school of Urban and Environmental Sciences Peking University Key Research Institute of Yellow River Civilization and Sustainable Development&Collaborative Innovation Center on Yellow River Civilization Henan Province and Ministry of Education Henan University 5. Key National Geomatics Center of China

Large-scale disasters can disproportionately impact different population groups, causing prominent disparity and inequality, especially for the vulnerable and marginalized. Here, we investigate the resilience of human mobility under the disturbance of the unprecedented ‘720’ Zhengzhou flood in china in 2021 using records of 1.32 billion mobile phone signaling generated by 4.35 million people. We find that although pluvial floods can trigger mobility reductions, the overall structural dynamics of mobility networks remain relatively stable. We also find that the low levels of mobility resilience in female, adolescent and older adult groups are mainly due to their insufficient capabilities to maintain business-as-usual travel frequency during the flood. Most importantly, we reveal three types of counter-intuitive, yet widely existing,resilience patterns of human mobility(namely, ‘reverse bathtub’, ‘ever-increasing’ and ‘ever-decreasing’ patterns), and demonstrate a universal mechanism of disaster-avoidance response by further corroborating that those abnormal resilience patterns are not associated with people’s gender or age. In view of the common association between travel behaviors and travelers’ socio-demographic characteristics, our findings provide a caveat for scholars when disclosing disparities in human travel behaviors during flood-induced emergencies.

关键词： disaster resilience urban flood human mobility Zhengzhou flood mobile phone data

Catalytic enantioselective domino alkenylation-alkynylation of alkenes: stereoselective synthesis of 5–7 membered azacycles and carbocycles

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Science china Chemistry 2023年第6期66卷 1701-1706页

作者： Zhaoming Ma Lantian Sun Jianrong Steve Zhou State Key Laboratory of Chemical Oncogenomics Guangdong Provincial Key Laboratory of Chemical GenomicsSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China Department of Chemistry Hong Kong Baptist UniversityHong KongChina

Enantioselective domino alkenylation-alkynylation of olefins is achieved for the first time,using terminal alkynes directly as *** new reaction enables facile construction of azacycles carrying quaternary stereocenters,including 5–7 membered pyrrolidines,piperidines and ***,alkynyl groups in azacyclic products provide a useful handle for derivatization that formed both fused and bridged azabicycles.

关键词： membered cycles synthesis

Modeling the pressure drop of wet gas in horizontal pipe

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Chinese Journal of Chemical Engineering 2017年第7期25卷 829-837页

作者： Peining Yu Yi Li Jing Wei Ying Xu Tao Zhang graduate school at shenzhen Tsinghua UniversityShenzhen 518055China CFHI Tianjin C-E Electrical Automation Co.Ltd Tianjin 300457China school of Electrical Engineering and Automation Tianjin UniversityTianjin 300072China

A model for gas–liquid annular and stratified flow through a horizontal pipe is investigated, using the two-phase hydrokinetics theory. Taking into consideration the flow factors including the void fraction, the friction between the two phases and the entrainment in the gas core, the one-dimensional momentum equation for gas has been solved. The differential pressure of the wet gas between the two tapings in the straight pipe has been modeled in the pressure range of 0.1–0.8 MPa. In addition a more objective iteration approach to determine the local void fraction is proposed. Compared with the experimental data, more than 83% deviation of the test data distributed evenly within the band of ± 10%. Since the model is less dependent on the specific empirical apparatus and data,it forms the foundation for further establishing a flow measurement model of wet gas which will produce fewer biases in results when it is extrapolated.

关键词： Gas-liquid flow Pressure drop Hydrodynamics Model

Study on scattering correction in fast neutron tomography at NECTAR facility

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Science china(Physics,Mechanics & Astronomy) 2014年第2期57卷 244-250页

作者： LIU ShuQuan BCHERL Thomas ZOU YuBin WANG Sheng LU YuanRong GUO ZhiYu State Key Lab of Nuclear Physics and Technology & school of Physics Peking University Technische Universit t München ZTWB Radiochemie München RCMWalther-Meissner-Str. 3Garching 85748Germany

Fast neutron tomography has been established as an inspection and detection tool at the NECTAR facility at the FRM-II reac- tor. Scattered neutrons from the object become a major disturbance and bring in artifacts and deviations in reconstruction re- suits, especially for hydrogenous material object. In this article, an iterative scattering correction method for fast neutron to- mography was proposed. In each loop of iteration the scattering component of the projections will be simulated by Mon- te-Carlo program MCNPX based on the previous reconstruction result and then it will be subtracted from original projections. The differences between scattering components at different perspectives were quantitatively evaluated and an average scatter- ing component image was used for all projections finally. Smooth and uniform slices with more clear edges were obtained and the new reconstructed attenuation coefficients are quite close to the real one compared to the results without scattering correc- tion, in which case the relative error of the reconstructed attenuation coefficients is about 10%-30%.

关键词： fast neutron scattering correction neutron tomography NECTAR