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QuEChERS-气相色谱质谱法测定土壤中5种氨基甲酸酯农药残留

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化学工程师 2024年第1期38卷 24-26,51页

作者：陈静文凤伟杨燕山东省临沂生态环境监测中心山东临沂276000 临沂市生态环境监察支队兰山大队山东临沂276000

建立QuEChERS-GC/MS法测定土壤中5种氨基甲酸酯农药残留的方法。实验结果表明,5种氨基甲酸酯农药标准曲线在5.00~400μg·L^(-1)浓度范围内线性关系良好,相关系数均大于0.995,加标回收率在88.7%~105.5%之间,相对标准偏差为1.86%~4.08%... 详细信息

建立QuEChERS-GC/MS法测定土壤中5种氨基甲酸酯农药残留的方法。实验结果表明,5种氨基甲酸酯农药标准曲线在5.00~400μg·L^(-1)浓度范围内线性关系良好,相关系数均大于0.995,加标回收率在88.7%~105.5%之间,相对标准偏差为1.86%~4.08%。该方法操作简单、灵敏度好、测试高效准确,可用于土壤中多种痕量氨基甲酸酯农药残留的测定。

关键词： QuEChERS 气相色谱质谱法土壤氨基甲酸酯农药残留

高效液相色谱质谱法测定水中7种苯甲酰脲类杀虫剂残留

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化学工程师 2024年第2期38卷 27-30页

作者：文凤伟杨燕陈静临沂市生态环境监察支队兰山大队山东临沂276000 山东省临沂生态环境监测中心山东临沂276000

建立了固相萃取技术富集、高效液相色谱质谱法同时测定水中氟幼脲、双苯氟脲等7种苯甲酰脲类杀虫剂残留的分析方法。水样经活化后的HLB固相萃取小柱提取浓缩,用10m L正己烷-丙酮(体积比为1∶1)洗脱柱,洗脱液氮吹至近干后加丙酮定容至1m... 详细信息

建立了固相萃取技术富集、高效液相色谱质谱法同时测定水中氟幼脲、双苯氟脲等7种苯甲酰脲类杀虫剂残留的分析方法。水样经活化后的HLB固相萃取小柱提取浓缩,用10m L正己烷-丙酮(体积比为1∶1)洗脱柱,洗脱液氮吹至近干后加丙酮定容至1m L,用高效液相色谱质谱法分析。氟幼脲、双苯氟脲等7种苯甲酰脲类杀虫剂在5.00~400μg·L^(-1)浓度范围内线性良好,方法检出限在0.03~0.08μg·L^(-1)之间,样品加标回收率为88.0%~103.4%,相对标准偏差为1.3%~4.2%。实验结果表明,该方法操作简单、灵敏度高、测试准确,可用于水中多种苯甲酰脲类杀虫剂残留的检测。

关键词：固相萃取水苯甲酰脲类杀虫剂高效液相色谱质谱法

SOLUTION CRYSTALLIZATION BEHAVIOR OF LINEAR AND STAR-SHAPED POLY(ETHYLENE GLYCOL)-b-POLY(ε-CAPROLACTONE) BLOCK COPOLYMERS

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Chinese Journal of Polymer Science 2013年第12期31卷 1717-1724页

作者： Ting Yu Jian-qiang Zhang Ya Lia Su-dan Shen wen-feng wei Peng Chen 王宗宝顾群 Ningbo Institute of Material Technology and Engineering Chinese Academy of Sciences School of Petrochemical Technology Lanzhou University of Technology Institute of Material Engineering Ningbo University of Technology

Lamellar crystals of diblock, triblock and four-arm poly（ethylene glycol）-b-poly（ε-caprolactone）（PEG-b-PCL） crystalline-crystalline copolymers were successfully obtained from their solution. Morphology and structure of lamellar crystals of crystalline-crystalline copotymers were investigated using tapping-mode atomic force microscopy （AFM） and selected area electron diffraction （SAED）. All of these samples showed the truncated-lozenge multilayer basal shapes with central screw dislocation or central stack, which were all obtained simultaneously from the oil bath. The diffraction pattern of PEG block lamellar crystal is attributed to the （120） diffracting planes and the pattern of PCL block lamellar crystal is attributed to the （1 I0） diffracting planes and （200） diffracting planes according to the SAED results. Four （110） crystal growth planes and two （200） crystal growth planes are discovered for the PCL blocks, but the （120） crystal growth planes of PEG blocks are hided in the figure of AFM. The crystalline structure of the four-arm copolymers （FA） is more disorder and confused than that of the diblock （DI） copolymer and the striated fold surface structures of lamellar crystals of four-arm copolymers （FA） are smoother than these of linear analogues, owing to the confused crystallization of blocks caused by the mutual restriction of blocks and the hindrance of the dendritic cores. In addition, the aspect ratio of FA is greater than that of the others. It is hypothesized that there are two reasons for the change of aspect ratios. First, the （200） diffracting planes of PCL crystals grew slowly compared to their （110） diffracting planes because of difference in the energy barrier. Secondly, edge dislocations on the （200） diffracting planes are also responsible for the variation of the aspect ratio. Consequently, the crystalline defects are augmented by the competing blocks crystallized simultaneously and the hindrance of the dendritic cores.

关键词： Lamellar crystal Topological structure PEG-b-PCL Edge dislocation Aspect ratio.

A Novel Adaptive Cooperative Location Algorithm for Wireless Sensor Networks

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International Journal of Automation and computing 2012年第5期9卷 539-544页

作者： wen-Jiang feng Xiao-wei Bi Rong Jiang College of Communication Engineering,Chongqing University,Chongqing 400044,China College of Communication Engineering Chongqing University Chongqing China

To overcome the disadvantages of the location algorithm based on received signal strength indication(RSSI) in the existing wireless sensor networks(WSNs),a novel adaptive cooperative location algorithm is *** tolerate some minor errors in the information of node position,a reference anchor node is *** the other hand,Dixon method is used to remove the outliers of RSSI,the standard deviation threshold of RSSI and the learning model are put forward to reduce the ranging error of RSSI and improve the positioning precision *** are run to evaluate the performance of the *** results show that the proposed algorithm offers more precise location and better stability and robustness.

关键词： Wireless sensor networks(WSNs) adaptive cooperative location positioning precision received signal strength indication(RSSI) Dixon method

Interparticle energy transfer between NaNdF_(4) and NaYbF_(4) in self-assembled nanostructures

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Journal of Rare Earths 2024年第6期42卷 1029-1035,I0001页

作者： Xinyu Chen Haoze Yang Yuyang Gu Chenqing wen Yishuo Sun Jiaming Ke wei feng Department of Chemistry and State Key Laboratory of Molecular Engineering of Polymers Fudan University Shanghai200433China

Forster resonance energy transfer(FRET)is a widely used spectroscopic *** development of donor-acceptor combinations is essential to advance this *** make the energy transfer efficiency independent of the external environment,we explored the potential of constructing donor—acceptor combinations with lanthanide ion-doped nanoparticles(LNPs),in which the 4f electrons of the lanthanide ions are shielded by the 5s and 6p ***-radiative energy transfer between LNPs was demonstrated in self-assembled nanostructures and core-shell structure of LNPs was used to control the distance between donor and acceptor in self-assembled *** emission intensity ratio of donor and acceptor illustrates that the energy transfer efficiency decreases significantly with increasing distance and the effective energy transfer distance is 8.5 nm,showing the potential of using LNPs as donor-acceptor pairs in the construction of distance-dependent energy transfer system.

关键词： Lanthanide nanoparticles Self-assembly Energy transfer Distance Epitaxialgrowth Rare earths

Significantly Enhanced Melt Memory Effect of Metallocene-made Isotactic Polypropylene Containing Talc

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Chinese Journal of Polymer Science 2024年第2期42卷 213-222,I0008页

作者： Hong-wen Sun Fu-Shan Wang Yan Gao Fu-Qing wei Jia-Chun feng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China Lanzhou Petrochemical Corporation of PetroChina Lanzhou730060China Lanzhou Petrochemical Research Center Petrochemical Research Institute of PetroChinaLanzhou730060China

The melt memory effect is a widely observed phenomenon in semi-crystalline polymers. In practical applications, various additives are usually introduced into polymers, which may affect their melt memory behavior. In this work, the effect of talc on the melt memory effect of metallocene-made isotactic polypropylene(M-PP) was investigated in detail by using the differential scanning calorimetry. The results indicated that the introduction of talc significantly strengthened the melt memory effect of M-PP. Specifically, the upper limit temperature of Domain II increased from 161 ℃ to 174 ℃, resulting in a substantial widening of the temperature range of Domain IIa from 1 ℃ to 14 ℃. Analysis of the crystal orientation of the M-PP containing talc cooled from various Ts suggested that the remarkably enhanced melt memory effect could be ascribed to the stabilization of oriented nuclei facilitated by talc. This stabilizing effect was likely attributable to the prefreezing effect or the sorption interaction between talc and the M-PP chains.

关键词： Metallocene-made isotactic polypropylene Talc Melt memory effect Crystal orientation

Deformation of Rigid Conjugate Self-dual Galois Representations

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1599-1644页

作者： Yi feng LIU Yi Chao TIAN Liang XIAO wei ZHANG Xin wen ZHU Institute for Advanced Study in Mathematics Zhejiang UniversityHangzhou 310058P.R.China Morningside Center of Mathematics AMSSChinese Academy of SciencesBeijing 100190P.R.China New Cornerstone Lab Beijing International Center for Mathematical ResearchPeking Ui Beijing 100871P.R.China Department of Mathematics Massachusetts Institute of TechnologyCambridge MA 02139United States Department of Mathematics Stanford UniversityStanfordCA 94305United States

In this article,we study deformations of conjugate self-dual Galois *** study is ***,we prove an R=T type theorem for a conjugate self-dual Galois representation with coefficients in a finite field,satisfying a certain property called ***,we study the rigidity property for the family of residue Galois representations attached to a symmetric power of an elliptic curve,as well as to a regular algebraic conjugate self-dual cuspidal representation.

关键词： Galois deformation rigid conjugate self-dual Galois representations

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Axial enantiomers with donor-regulated TADF feature for multicolor circularly polarized electroluminescence

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Science China Chemistry 2024年第6期67卷 2039-2045页

作者： Chen-Hao Guo wen-Long Zhao Ke-Ke Tan wei-Chen Guo Liheng feng Chuan-feng Chen Meng Li School of Chemistry and Chemical Engineering Shanxi UniversityTaiyuan030006China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

This study optimized the TADF feature of axial chiral enantiomers through precise donor engineering,and multicolor CP-TADFwas achieved in the axial chiral *** pairs of axial enantiomers with donor-regulated TADF feature,namely(R/S)-TPCBD,(R/S)-DPCBD,and(R/S)-DPACBD,were synthesized by introducing carbazole donors with different substituents onto biphenyl cyanide *** the electron-donating ability of donors increases,the emission of these axial enantiomers ranges from 455,476 to 552 nm,their singlet-triplet energy gaps(ΔE_(ST))gradually decrease from 0.30,0.22 to 0.02 e V,accompanied by an increasement in the transition rate(k_(RISC))of RISC process,and the k_(RISC)of DPACBD could reach up to 7.16×10^(5)s^(-1).These axial enantiomers also exhibit mirror-image CD and circularly polarized luminescence(CPL)***,OLEDs based on TPCBD,DPCBD,and DPACBD as emitter were then fabricated,which displayed blue,green,and orange electroluminescence with EQE_(max)of 13.0%,16.4%,and 25.0%,*** results also exhibited a phenomenon of device efficiency increasing with the enhancement of donor ***,the CP-OLEDs using(R/S)-TPCBD,(R/S)-DPCBD and(R/S)-DPACBD as emitters displayed intense CPEL signals with g_(EL)values of 3.4×10^(-3)/-4.1×10^(-3),3.2×10^(-3)/-3.1×10^(-3)and2.3×10^(-3)/-2.1×10^(-3),*** convenient molecular engineering of donor regulation in the same molecular skeleton,CP-TADF materials with multicolor CPEL and improved device performance could be conveniently achieved.

关键词： axial chirality thermally activated delayed fluorescence circularly polarized luminescence electroluminescence organic light-emitting diodes

A novel refined dynamic model of high-speed maglev train-bridge coupled system for random vibration and running safety assessment

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Journal of Central South University 2024年第7期31卷 2532-2544页

作者： MAO Jian-feng LI Dao-hang YU Zhi-wu CAI wen-feng GUO wei ZHANG Guang-wen School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-speed Railway Construction Technology Changsha 410075China China Railway Group Limited Beijing 100039China China Railway Eryuan Engineering Group Co. Ltd.Chengdu 610031China

Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic *** motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element *** model is proven to be applicable by comparing with Monte Carlo *** applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability ***,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are *** results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.

关键词： maglev train-bridge interaction electromagnetic force-air gap model stochastic dynamic analysis running safety assessment probability density evolution method