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

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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 *** 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 *** 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 *** 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 *** 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 *** 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 *** 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

快速滤过型净化结合气相色谱-三重四级杆串联质谱法同时检测土壤中23种有机氯农药

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化学研究与应用 2024年第6期36卷 1420-1426页

作者：范文耀曹立峰王敏捷张兰张南河南省岩石矿物测试中心河南郑州450000

本文建立了快速滤过型净化(m-PFC)结合气相色谱-三重四级杆串联质谱(GC-MS/MS)同时测定土壤中23种有机氯农药(OCPs)的方法。对影响OCPs回收率的主要因素进行优化,得出最优的萃取条件:2次静态萃取循环,每次静态萃取5min,100℃的萃取温度... 详细信息

本文建立了快速滤过型净化(m-PFC)结合气相色谱-三重四级杆串联质谱(GC-MS/MS)同时测定土壤中23种有机氯农药(OCPs)的方法。对影响OCPs回收率的主要因素进行优化,得出最优的萃取条件:2次静态萃取循环,每次静态萃取5min,100℃的萃取温度,正己烷/丙酮(1:1,V/V)为萃取液。研究发现了适合佛罗里硅土柱净化的洗脱液配比,比较了佛罗里硅土柱净化和m-PFC净化对土壤萃取液的净化效果,结果表明,m-PFC净化能减少前处理流程,提高前处理效率,且有较高回收率。23种OCPs在相应的范围内有良好的线性关系,相关系数(r^(2))均大于0.995,加标回收率为81.7%~112%,RSD为0.6%~5.8%,当取样量为20.00 g时,方法的检出限为0.004~0.029μg·kg^(-1),定量下限为0.016~0.116μg·kg^(-1)。

关键词：快速滤过型净化气相色谱-串联质谱有机氯农药土壤加速溶剂萃取

Modified Sadowski formula-based model for the slope shape amplification effect under multistage slope blasting vibration

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International Journal of Mining Science and Technology 2024年第5期34卷 631-641页

作者： Xiaogang Wu Mingyang Wang Hao Lu Yongjun zhang Wen Nie State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China State Key Laboratory of Metal Mine Safety and Health Ma’anshan 243000China School of Civil Engineering Qingdao University of TechnologyQingdao 266520China

Blasting operations,which are crucial to open-pit mine production due to their simplicity and efficiency,require precise control through accurate vibration velocity *** conventional Sadowski formula mainly focuses on blast center distance but neglects the amplification effect of blasting vibration waves by terraced terrain,from which the calculated blasting vibration velocities are smaller than the actual values,affecting the safety of the *** address this issue,our model introduces the influences of slope and time into Sadowski formula to measure safety through blast vibration *** the northern section of the open-pit quartz mine in Jinchang City,Gansu Province,China,the data of a continuous blasting slope project are referred *** findings reveal a noticeable vibration amplification effect during blasting when a multi-stage slope platform undergoes a sudden cross-sectional change near the upper overhanging *** amplification vibration coefficient increases with height,while vibration waves within rocks decrease from bottom to ***,platforms without distinct crosssectional changes exhibit no pronounced amplification during *** addition,the vibration intensity decreases with distance as the rock height difference change *** results obtained by the proposed blast vibration displacement equation incorporating slope shape influence closely agree with real-world *** to Pearson correlation coefficient(PPMCC)analysis,the average accuracy rate of our model is 88.84%,which exceeds the conventional Sadowski formula(46.92%).

关键词： Multistage slope Slope shape influence factor Continuous blasting Sadowski formula Amplification effect

Cross-border E-commerce and China's Exports during the COVID-19 Pandemic

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China & World Economy 2024年第3期32卷 215-242页

作者： Yi Che Meng Yuan Yan zhang Lin Zhao School of Business East China University of Science and TechnologyChina School of Business Xiangtan UniversityChina School of Economics Shanghai University of Finance and EconomicsChina

China's exports experienced a rapid recovery after the outbreak of the 2019 COVID-19 pandemic.A primary engine was cross-border e-commerce(CBEC)trade,which bucked the downward export trend during the *** exploring the variation in the number of CBEC comprehensive pilot zones across provinces,we identified the causal impact of CBEC on exports using monthly province-product-destination data for 2019 and *** found strong and robust evidence that CBEC contributed to exports during the pandemic by promoting the expansion of incumbent exports(intensive margin)rather than through the expansion of product categories and exporting partners(extensive margin).Specifically,higher pandemic risk suppressed the role of CBEC at the intensive margin while enhancing it at the extensive *** to developed countries benefited more from CBEC,both intensively and *** with final products,a larger number of intermediate products were exported through CBEC after the outbreak of the pandemic.

关键词： China's exports COVID-19 pandemic cross-border e-commerce extensive margin of trade intensive margin of trade

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航空发动机机匣数控加工参数研究

制造技术与机床 2024年第8期 9-15页

作者：张新运王泽箫曹岩董建耿楠西安工业大学机电工程学院陕西西安710021

航空发动机机匣作为发动机的主要零部件,通常选用高温合金毛坯加工而成,铣削力等评价指标将严重影响此类零件的加工效率以及加工质量。首先,通过研究机匣的加工工艺,应用DEFORM-3D软件对材料为镍基合金GH4169的机匣粗铣加工过程进行了... 详细信息

航空发动机机匣作为发动机的主要零部件,通常选用高温合金毛坯加工而成,铣削力等评价指标将严重影响此类零件的加工效率以及加工质量。首先,通过研究机匣的加工工艺,应用DEFORM-3D软件对材料为镍基合金GH4169的机匣粗铣加工过程进行了铣削仿真分析,以铣削力为评价指标,通过仿真分析,得到不同铣削参数下铣削力的变化规律。其次,针对仿真结果进行方差分析,得出不同指标对铣削力的影响大小,根据仿真结果对参数进行拟合,建立机匣铣削加工过程中铣削力预测模型。最后,运用遗传算法进行算法寻优,得到一组最优的铣削参数,为机匣实际加工提供指导依据。

关键词：机匣加工工艺有限元仿真预测模型算法寻优

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Analysis of the interaction between bolt-reinforced rock and surface support in tunnels based on convergence-confinement method

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 1936-1951页

作者： Zhenyu Sun Dingli zhang Qian Fang Yanjuan Hou nanqi Huangfu Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing100044China

To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockbolts and the surface *** rock mass is assumed to be elastic-brittle-plastic material,obeying the linear Mohr-Coulomb criterion or the non-linear Hoek-Brown *** to the strain states of the tunnel wall at bolt and surface support installation and the relative magnitude between the bolt length and the plastic depth during the whole process,six cases are categorized upon solving the *** case is divided into three stages due to the different effects of the active rockbolts and the passive surface *** fictitious pressure is introduced to quantify the threedimensional(3D)effect of the tunnel face,and thus,the actual physical location along the tunnel axis of the analytical section can be *** using the bolt-rock strain compatibility and the rocksurface support displacement compatibility conditions,the solutions of longitudinal tunnel displacement and the reaction pressure of surface support along the tunnel axis are *** proposed analytical solutions are validated by a series of 3D numerical *** parametric studies are conducted to examine the effect of the typical parameters of rockbolts and surface support on the tunnel displacement and the reaction pressure of the surface support under different rock *** results show that the rockbolts are more effective in controlling the tunnel displacement than the surface support,which should be installed as soon as possible with a suitable *** tunnels excavated in weak rocks or with restricted displacement control requirements,the surface support should also be installed or closed timely with a certain *** proposed method provides a convenient alternative approach for the optimization of rockbolts and surface support

关键词： Analytical model Longitudinal tunnel displacement Fictitious pressure Active rockbolts Surface support reaction pressure Tunnel design

Convergence Towards the Population Cross-Diffusion System from Stochastic Many-Particle System

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Communications in Mathematical Research 2024年第1期40卷 43-63页

作者： Yue Li Li Chen Zhipeng zhang Department of Mathematics Nanjing UniversityNanjing 210093P.R.China Institute for Analysis and Scientific Computing Vienna University of TechnologyWiedner Hauptstrafβe 8-10Vienna 1040Austria School of Business Informatics and Mathematics University of MannheimMannheim 68131Germany

In this paper,we derive rigorously a non-local cross-diffusion system from an interacting stochastic many-particle system in the whole *** convergence is proved in the sense of probability by introducing an intermediate particle system with a mollified interaction potential,where the mollification is of algebraic *** main idea of the proof is to study the time evolution of a stopped process and obtain a Gronwall type estimate by using Taylor's expansion around the limiting stochastic process.

关键词： Stochastic particle systems cross-diffusion system mean-field limit population dynamics

Heteroatom tuning in agarose derived carbon aerogel for enhanced potassium ion multiple energy storage

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Carbon Energy 2024年第3期6卷 239-254页

作者： Kaijun Xie Xin Liu Haolin Li Long Fang Kai Xia Dongjiang Yang Yihui Zou Xiaodong zhang State Key Laboratory of Bio-fibers and Eco-textiles Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological TextilesInstitute of Marine Biobased MaterialsCollege of Chemistry and Chemical EngineeringCollege of Environmental Science and EngineeringQingdao UniversityQingdaoChina

The incorporation of heteroatoms into carbon aerogels(CAs)can lead to structural distortions and changes in active sites due to their smaller size and electronegativity compared to pure ***,the evolution of the electronic structure from single-atom doping to heteroatom codoping in CAs has not yet been thoroughly investigated,and the impact of codoping on potassium ion(K+)storage and diffusion pathways as electrode material remains *** this study,experimental and theoretical simulations were conducted to demonstrate that heteroatom codoping,composed of multiple heteroatoms(O/N/B)with different properties,has the potential to improve the electrical properties and stability of CAs compared to single-atom *** states near the Fermi level have revealed that doping with O/N/B generates a greater number of active centers on adjacent carbon atoms than doping with O and O/N *** a result of synergy with enhanced wetting ability(contact angle of 9.26°)derived from amino groups and hierarchical porous structure,ON-CA has the most optimized adsorption capacity(−1.62 eV)and diffusion barrier(0.12 eV)of K^(+).The optimal pathway of K^(+)in ON-CA is along the carbon ring with N or O *** K^(+)storage material for supercapacitors and ion batteries,it shows an outstanding specific capacity and capacitance,electrochemical stability,and rate ***,the assembled symmetrical K^(+)supercapacitor demonstrates an energy density of 51.8 Wh kg^(−1),an ultrahigh power density of 443Wkg^(−1),and outstanding cycling stability(maintaining 83.3%after 10,000 cycles in 1M KPF6 organic electrolyte).This research provides valuable insights into the design of highperformance potassium ion storage materials.

关键词： agarose carbon aerogels O/N/B codoping potassium-ion battery potassium-ion supercapacitor

Evolution of China's Role in the Structure of Global Carbon Emission Transfers:An Empirical Analysis Based on Network Governance

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China & World Economy 2024年第1期32卷 130-166页

作者： Bingbing zhang Lelan Kong Zhehong Xu Chuanwang Sun School of Economics and Management Nanjing Agricultural University Jiangsu Provincial Center for Agricultural Foreign Cooperation and Communication China Paula and Gregory Chow Institute for Studies in Economics Xiamen UniversityChina China Center for Energy Economics Research School of Economics and MOE Key Laboratory of EconometricsXiamen UniversityChina

This paper reconsiders the roles of China and some developed countries in the network of carbon emission transfers via international trade in value added from a new perspective of network *** search intensity(NSI)and the extended gravity model are used with cross-country panel data to analyze the mechanism of China's engagement in network governance of carbon emission *** results show that from 2000 to 2009,China was a net exporter of carbon emissions,even though it shifted from the semi-periphery to the core in the network of carbon emissions embodied in ***,NSI had a significant positive impact on carbon emissions embodied in *** China's important role in the global production network and division of labor,NSI may also affect industrial structure and the quality of the ecological environment to a large *** study analyses the network governance mechanism of China's participation in global carbon *** results suggest that the technical complexity of export products and product heterogeneity do not change the positive impact of NSI on carbon emissions.

关键词： carbon emission transfers gravity model network governance network search intensity