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聚乙烯亚胺修饰氧化石墨烯材料选择性吸附分离乌龙茶叶中无机砷的研究

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食品安全质量检测学报 2022年第12期13卷 3859-3866页

作者：刘皓良罗杰高照杰林艳郭溪远程杨陈嘉慧蓝荷英陈团伟福建农林大学食品科学学院福州350002

目的将聚乙烯亚胺(polyethyleneimine,PEI)修饰于氧化石墨烯(graphene oxide,GO)表面,制备PEI@GO合成材料以实现乌龙茶叶中无机砷的选择性吸附分离,并结合原子荧光光谱法对其进行检测。方法利用傅里叶红外光谱、电镜扫描、Zeta电位分析... 详细信息

目的将聚乙烯亚胺(polyethyleneimine,PEI)修饰于氧化石墨烯(graphene oxide,GO)表面,制备PEI@GO合成材料以实现乌龙茶叶中无机砷的选择性吸附分离,并结合原子荧光光谱法对其进行检测。方法利用傅里叶红外光谱、电镜扫描、Zeta电位分析对PEI@GO进行表征,并建立基于PEI@GO的管尖固相萃取(pipette tip solid phase extraction,PTSPE)体系结合氢化物发生-原子荧光光谱法(hydride generation atomic fluorescence spectrometry,HG-AFS)实现乌龙茶中无机砷的选择性吸附分离和准确定量。结果傅里叶红外光谱图中出现N-H特征峰,表明PEI成功修饰于GO的表面,电镜下PEI@GO呈现多孔的山脊山谷结构,Zeta电位分析其等电点约为9.7,在pH 6下,5 mg PEI@GO对As(V)溶液吸附率达95.84%,所建立的PTSPE-HG-AFS法最低检出限为0.027μg/L,相对标准偏差为0.48%,不同品种乌龙茶样品中无机砷含量为13.00~122.00μg/kg,回收率在86.48%~108.98%之间。结论制备的PEI@GO材料可有效实现无机砷的选择性吸附分离,所建立的方法操作简便、灵敏度高,可准确用于实际茶叶样品中无机砷的分析检测。

关键词：聚乙烯亚胺氧化石墨烯乌龙茶叶无机砷选择性吸附分离

A new prediction method of industrial atmospheric pollutant emission intensity based on pollutant emission standard quantification

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Frontiers of Environmental Science & Engineering 2023年第1期17卷 87-97页

作者： Tienan Ju Mei Lei Guanghui guo Jinglun xi Yang Zhang yuan Xu Qijia Lou Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Industrial emissions are the main source of atmospheric pollutants in *** and reasonable prediction of the emission of atmospheric pollutants from single enterprise can determine the exact source of atmospheric pollutants and control atmospheric pollution *** on China’s coking enterprises in 2020,we proposed a quantitative method for pollutant emission standards and introduced the quantification results of pollutant emission standards(QRPES)into the construction of support vector regression(SVR)and random forest regression(RFR)prediction methods for SO_(2) emission of coking enterprises in *** results show that,affected by the types of coke ovens and regions,China’s current coking enterprises have implemented a total of 21 emission standards,with marked *** adding QRPES,it was found that the root mean squared error(RMSE)of SVR and RFR decreased from 0.055 kt/a and 0.059 kt/a to 0.045 kt/a and 0.039 kt/a,and the R2 increased from 0.890 and 0.881 to 0.926 and 0.945,*** shows that the QRPES can greatly improve the prediction accuracy,and the SO_(2) emissions of each enterprise are highly correlated with the strictness of *** predicted result shows that 45%of SO_(2) emissions from Chinese coking enterprises are concentrated in Shanxi,Shaanxi and Hebei provinces in central *** method created in this paper fills in the blank of forecasting method of air pollutant emission intensity of single enterprise and is of great help to the accurate control of air pollutants.

关键词： Industrial atmospheric pollutants Pollutant emission standards Quantitative method Machine learning Single enterprise

Low‑Temperature Oxidation Induced Phase Evolution with Gradient Magnetic Heterointerfaces for Superior Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第1期17卷 191-204页

作者： Zizhuang He Lingzi Shi Ran Sun Lianfei Ding Mukun He Jiaming Li Hua guo Tiande Gao Panbo Liu School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an 710129People’s Republic of China School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072People’s Republic of China

Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching,adjusting dielectric/magnetic resonance and promoting electromagnetic(EM)wave absorption,but still exist a significant challenging in regulating local phase ***,accordion-shaped Co/Co_(3)O_(4)@N-doped carbon nanosheets(Co/Co_(3)O_(4)@NC)with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and lowtemperature oxidation *** results indicate that the surface epitaxial growth of crystal Co_(3)O_(4) domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components,which are beneficial for optimizing impedance matching and interfacial ***,gradient magnetic heterointerfaces simultaneously realize magnetic coupling,and long-range magnetic ***,the synthesized Co/Co_(3)O_(4)@NC absorbents display the strong electromagnetic wave attenuation capability of−53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz,both are superior to those of single magnetic domains embedded in carbon *** design concept provides us an inspiration in optimizing interfacial polarization,regulating magnetic coupling and promoting electromagnetic wave absorption.

关键词： Magnetic heterointerfaces Phase evolution Interfacial polarization Magnetic coupling Electromagnetic wave absorption

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超压凝析气藏的流体相态和物理性质

石油学报 2004年第4期25卷 71-74页

作者：郜国喜袁士义宋文杰李海平罗凯塔里木油田勘探开发研究院新疆库尔勒841000 中国石油勘探开发研究院北京100083 西南石油学院

在国内发现的高温高压凝析气藏越来越多 ,所以须加强对这类气藏流体相态和物性的实验和理论研究。应用某气田地面油气样品 ,在实验室配制了高含蜡凝析气流体 ,研究了高含蜡凝析气在压力很高时的相态和物理参数。通过流体等质膨胀实验 ,... 详细信息

在国内发现的高温高压凝析气藏越来越多 ,所以须加强对这类气藏流体相态和物性的实验和理论研究。应用某气田地面油气样品 ,在实验室配制了高含蜡凝析气流体 ,研究了高含蜡凝析气在压力很高时的相态和物理参数。通过流体等质膨胀实验 ,确定了流体露点压力和相应的实验特性 ,给出了超高压下的压缩因子等数据。采用Dranchk等人的关系式计算了流体在超高压状态下的偏差因子。结果表明 ,计算值明显小于实验数值 ,误差大于 10 % ,且随压力的增大误差也增大。地层流体含有大量的蜡组分 ,在流体压力大于露点压力时。

关键词：高温高压凝析气藏高含蜡凝析气流体相态压缩因子物理性质

Kloosterman Sums and a Problem of ***

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Chinese Annals of Mathematics,Series B 2020年第3期41卷 361-370页

作者： Ping xi yuan YI School of Mathematics and Statistics Xi’an Jiaotong UniversityXi’an 710049China

A classical problem of D. H. Lehmer suggests the study of distributions of elements of Z/pZ of opposite parity to the multiplicative inverse mod p. Zhang initiated this problem and found an asymptotic evaluation of the number of such elements. In this paper, an asymptotic formula for the fourth moment of the error term of Zhang is proved,from which one may see that Zhang’s error term is optimal up to the logarithm *** method also applies to the case of arbitrary positive integral moments.

关键词： D.H.Lehmer problem Kloosterman sum Moment

Atropoenantioselective synthesis of heterobiaryl N-oxides via dynamic kinetic resolution

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Science China Chemistry 2022年第12期65卷 2512-2516页

作者： xi yuan Jian Wang College of Chemistry and Materials Science Anhui Normal UniversityWuhu241002China School of Pharmaceutical Sciences Tsinghua UniversityBeijing100084China

A highly efficient enantioselective construction of heterobiaryl N-oxides was developed.A series of axially chiral heterobiaryl N-oxides were generated via the cascade reaction of aminobenzamides with heterobiaryl aldehydes in the presence of chiral phosphoric acids.A number of atropisomers were afforded in moderate to good yields with excellent enantioselectivities and *** results demonstrate that the heterobiaryl N-oxides can be utilized as efficient chiral ligands in asymmetric catalysis.

关键词： heterobiaryl N-oxides dynamic kinetic resolution chiral phosphoric acids atroposelectivity organocatalysis

The excluded-volume effect in microscopic pedestrian simulations

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Chinese Physics B 2012年第1期21卷 539-548页

作者： guo Ren-Yong guo xi College of Computer Science Inner Mongolia UniversityHohhot 010021China School of Public Administration Inner Mongolia UniversityHohhot 010021China

We propose a pedestrian position update rule, which is added to a microscopic pedestrian model to avoid pedestrian overlap. In the rule, the step size of a pedestrian moving in a selected direction at each update is in inverse proportion to the repulsive actions imposed by other pedestrians moving in a direction with an exponential rate. The positions of the pedestrians are then updated in each small time interval. In this way, a barrier between the pedestrians can be generated, and after updating their positions the pedestrians do not overlap with each other. The modified model is compared to the original model through a simulation of the evacuation process of pedestrians in a closed area. The simulation results indicate that the modified model is superior to the original model in several aspects.

关键词： pedestrian model excluded-volume effect discrete dynamic system

Sulfur dioxide sensing properties of MOF-derived ZnFe_(2)O_(4) functionalized with reduced graphene oxide at room temperature

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Rare Metals 2021年第6期40卷 1604-1613页

作者： Lan-Juan Zhou xi-xi Zhang Wen-yuan Zhang College of Control Science and Engineering China University of Petroleum(East China)Qingdao 266580China United Microelectronics Center Chongqing 401332China

In this paper,ZnZnFe_(2)O_(4) nanorods were prepared using Zn/Fe metal organic framework(MOF)as precursors,and ZnZnFe_(2)O_(4)/reduced graphene oxide(rGO)was prepared by hydrothermal *** morphology and composition of the ZnZnFe_(2)O_(4)/rGO nanocomposite were characterized,and the results showed that the MOF-derived ZnZnFe_(2)O_(4) nanorods are uniformly modified on the surface of *** ZnZnFe_(2)O_(4)/rGO nanocomposite exhibits better SO_(2) gas sensing performance than the single ZnZnFe_(2)O_(4) nanorods at room *** sensing characteristics of single ZnZnFe_(2)O_(4) film sensor,single rGO film sensor and ZnZnFe_(2)O_(4)/rGO composite film sensor at SO_(2)gas concentration(1×10^(-6)-100×10^(-6))were *** response of ZnZnFe_(2)O_(4)/rGO composite sensor can reach 18.32%at room *** with single ZnZnFe_(2)O_(4) and rGO film sensors,the ZnZnFe_(2)O_(4)/rGO composite sensor has better transient response,good sensitivity and *** this work,the improvement of the sensor performance is not only due to the p-n heterostructure between ZnZnFe_(2)O_(4) nanorods and rGO nanosheets,but also to the excellent electrical properties of *** provides a new idea for the detection of SO_(2) at room temperature.

关键词： Ternary metal oxide ZnFe_(2)O_(4)nanorods Reduced graphene oxide SO_(2)gas sensor

高速转轴密封微间隙润滑气膜形成与影响因素研究

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化工机械 2021年第1期48卷 84-88,105页

作者：邹龙庆刘佳琪付海龙王玥郭晰元东北石油大学机械科学与工程学院东北石油大学环渤海能源研究院

以天然气井高压旋转控制头为工程背景,利用流体动压机理,针对高转速轴密封问题,提出通过在密封橡胶与轴微间隙接触界面建立润滑气膜,以有效解决橡胶干摩擦失效问题。在胶芯内壁构建螺旋槽,改变柱状摩擦副接触面结构,以产生气体动压效应... 详细信息

以天然气井高压旋转控制头为工程背景,利用流体动压机理,针对高转速轴密封问题,提出通过在密封橡胶与轴微间隙接触界面建立润滑气膜,以有效解决橡胶干摩擦失效问题。在胶芯内壁构建螺旋槽,改变柱状摩擦副接触面结构,以产生气体动压效应。通过建立柱面微间隙气膜模型,实现了气膜流场数值模拟,并验证了螺旋槽结构参数、转速变化等因素对气膜的影响规律。结果表明:偏心率是润滑气膜形成的必要条件;在偏心率和转速一定的条件下,螺旋槽与轴转动方向相反且旋向为50°时,气膜压力最大,可获得最佳气体动压效应。

关键词：高速转轴密封气膜密封胶芯微间隙动压效应偏心率