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磺化改性聚四氟乙烯纤维固相萃取-高效液相色谱联用测定奶制品中的三聚氰胺

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应用化学 2011年第4期28卷 448-453页

作者：张毅韩晓燕赵培莉郭炜毅张政朴天津中医药大学实验教学部天津天津中医药大学中药学院天津市中药化学与分析重点实验室天津300193 南开大学高分子所功能高分子材料教育部重点实验室天津

采用新型固相萃取材料磺化的甲基丙烯酸缩水甘油酯接枝聚四氟乙烯(PTFE-g-GMA-SO3H)纤维填充微柱预富集和流动注射(FI)与高效液相色谱(HPLC)联用测定样品中痕量的三聚氰胺。建立了以该纤维作为吸附剂在线测定奶制品中三聚氰胺的新方法... 详细信息

采用新型固相萃取材料磺化的甲基丙烯酸缩水甘油酯接枝聚四氟乙烯(PTFE-g-GMA-SO3H)纤维填充微柱预富集和流动注射(FI)与高效液相色谱(HPLC)联用测定样品中痕量的三聚氰胺。建立了以该纤维作为吸附剂在线测定奶制品中三聚氰胺的新方法。对三聚氰胺的富集与洗脱条件进行了优化,并得出三聚氰胺的分析特性:该方法对三聚氰胺的检出限为1.13×10-2 mg/L,富集倍数为300,RSD为7.6%(n=9,三聚氰胺质量浓度为0.2 mg/L)。该方法应用于2种奶制品中的痕量三聚氰胺的测定,样品加标回收率分别为98%和102.5%。

关键词：磺化的接枝甲基丙烯酸缩水甘油酯的聚四氟乙烯纤维在线固相萃取三聚氰胺

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次磷酸的新型生产方法的研究

离子交换与吸附 2001年第3期17卷 271-275页

作者：程建忠张英喆张宝贵张政朴南开大学高分子研究所!天津 300071 南开大学环境科学与工程学院!天津 300071

本文采用电渗析法制取次磷酸，工艺简单，产品纯度高，设备投入小，适于大规模生产。

关键词：次磷酸电渗析

RFID技术在动车组零部件管理中的应用探讨

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铁路计算机应用 2013年第4期22卷 44-45页

作者：张正普张研戴建强中国铁道科学研究院电子计算技术研究所北京100081

我国动车组的快速发展和广泛使用,使其零部件的管理在生产、组装及日后维修中面临很大的压力。如何利用合理的工具使动车组零部件管理合理有序,很大程度影响动车组的运营。本文提出利用带有电子纸技术的RFID电子标签,配合后台应用程序... 详细信息

我国动车组的快速发展和广泛使用,使其零部件的管理在生产、组装及日后维修中面临很大的压力。如何利用合理的工具使动车组零部件管理合理有序,很大程度影响动车组的运营。本文提出利用带有电子纸技术的RFID电子标签,配合后台应用程序统一管理动车组零部件,不失为动车组零部件管理的一个比较理想的手段。

关键词： RFID电子标签电子纸动车组零部件管理

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药用缓释材料聚乳酸-乙醇酸共聚物的研制

天津药学 2007年第1期19卷 13-15页

作者：刘苗苗张政朴天津市计划生育研究所天津300191 南开大学高分子化学研究所天津300070

目的：合成药用聚乳酸-乙醇酸高分子缓释材料，用于某些生物药物缓、控释剂型的制备；同时探讨聚合反应条件的影响因素以及优化工艺。方法：在一定的温度和压力下，采用配位-插入聚合法通过交酯开环合成聚乳酸-乙醇酸共聚物缓释材料。... 详细信息

目的：合成药用聚乳酸-乙醇酸高分子缓释材料，用于某些生物药物缓、控释剂型的制备；同时探讨聚合反应条件的影响因素以及优化工艺。方法：在一定的温度和压力下，采用配位-插入聚合法通过交酯开环合成聚乳酸-乙醇酸共聚物缓释材料。结果：本研制合成的聚乳酸-乙醇酸共聚物（PLGA75／25和PLGA50／50）经采用多种鉴定手段表征化学结构正确，力学性能良好，玻璃转化温度为33．7℃，分子量为27000～70000，分子量分布为1．4～1．6，产品最终产率可达70％以上。结论：通过制备工艺条件的控制和优化，在一定范围内，不仅可以得到分子量大小不等和单体比例不同的聚乳酸-乙醇酸缓释材料，而且每批次之间所得分子量重现性良好，合成工艺稳定、可靠。

关键词：高分子缓释材料聚乳酸-乙醇酸共聚物

Diatomic Pd catalyst with conjugated backbone for synergistic electrochemical CO_(2)reduction

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Nano Research 2024年第6期17卷 4850-4855页

作者： Wenxuan zhang Mengran zhang Hongjuan Wang Wen zhang Min zhang MOE International Joint Laboratory of Materials Microstructure Institute for New Energy Materials and Low Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry and Chemical EngineeringTianjin University of TechnologyTianjin 300384China

Double-site catalysts have attracted widespread attention in the field of electrocatalysis due to their high metal loading,adjustable active centres,and electronic valence ***,the development of bimetallic sites catalysts that coordinate with definite atoms is still in the exploratory ***,we designed and synthesized a bimetallic palladium complex(BPB-Pd_(2))with conjugated *** supported BPB-Pd_(2)was applied to electrochemical CO_(2)reduction reaction(CO_(2)RR)for the first *** as-obtained BPB-Pd_(2)gives an exceptional Faradaic efficiency of CO(FECO)of 94.4%at−0.80 V *** hydrogen electrode(RHE),which is significantly superior to monoatomic palladium catalyst(BPB-Pd1).The density functional theory(DFT)calculations revealed that the essential reason for the outstanding activity of BPB-Pd_(2)toward CO_(2)RR was that the electronic effect between diatomic palladium reduces the free energy change for CO_(2)RR ***,BPB-Pd_(2)exhibits moderate free energy change to form COOH*intermediate,which was beneficial for the generation of CO in CO_(2)RR.

关键词： synthesis electrocatalysis CO_(2)reduction bimetallic palladium complex synergistic catalysis

N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu Yuan Yao zhang Xiaoyan zhang Junjie zhang Shen’gen zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis

Reversing free-electron transfer of sulfide cocatalyst for exceptional photocatalytic H_(2)evolution

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Journal of Materials Science & Technology 2024年第4期171卷 147-149页

作者： Yanfeng zhang Zhenyi zhang National Experimental Chemistry Teaching Center Hebei Key Laboratory of Inorganic Nano-materialsCollege of Chemistry and Materials ScienceHebei Normal UniversityShijiazhuang 050024China Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning ProvinceSchool of Physics and Materials EngineeringDalian Minzu UniversityDalian 116600China

Recently,Yu and co-workers deeply explore the potential impact of free electron transfer between co-catalysts and photocatalyst carriers on H_(2)evolution efficiency of active sites over MoS_(2+x).They pro-pose an electron-reversal tactics to evade the unexpected electron transfer and synchronously regulate the above transfer in a beneficial orientation for weakening hydrogen adsorption on S ***,this highlight not only discusses and summarizes the essences of electron reversal and the optimized H ad-sorption/desorption mechanism,but also emphasizes the significance of femtosecond transient absorp-tion spectroscopy(fs-TAS)and in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)for revealing charge transfer dynamics and *** anticipate that this highlight can disseminate a new per-spective on the roles of photocatalyst carriers in improving cocatalytic H_(2)-production kinetics.

关键词： Photocatalysis Cocatalyst Electron reversal Antibonding-orbital occupancy S–H bonds

Inter-well internal resonance analysis of rectangular asymmetric cross-ply bistable composite laminated cantilever shell under transverse foundation excitation

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1353-1370页

作者： Lele REN Wei zhang Yufei zhang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanics Guangxi UniversityNanning 530004China Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures College of Mechanical EngineeringBeijing University of TechnologyBeijing 100124China

The chaotic dynamic snap-through and complex nonlinear vibrations are investigated in a rectangular asymmetric cross-ply bistable composite laminated cantilever shell,in cases of 1:2 inter-well internal resonance and primary *** transverse foundation excitation is applied to the fixed end of the structure,and the other end is in a free *** first-order approximate multiple scales method is employed to perform the perturbation analysis on the dimensionless two-degree-of-freedom ordinary differential motion control *** four-dimensional averaged equations are derived in both polar and rectangular coordinate *** from the obtained frequency-amplitude and force-amplitude response curves,a detailed analysis is conducted to examine the impacts of excitation amplitude,damping coefficient,and tuning parameter on the nonlinear internal resonance characteristics of the *** nonlinear softening characteristic is exhibited in the upper stable-state,while the lower stable-state demonstrates the softening and linearity *** simulation is carried out using the fourth-order Runge-Kutta method,and a series of nonlinear response curves are *** the excitation amplitude further elucidates the global bifurcation and chaotic dynamic snap-through characteristics of the bistable cantilever shell.

关键词： bistable composite laminated cantilever shell inter-well internal resonance primary resonance chaotic dynamic snap-through complex nonlinear vibration

Oxygen reduction electrocatalysis:From conventional to single-atomic platinum-based catalysts for proton exchange membrane fuel cells

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Frontiers in Energy 2024年第2期18卷 206-222页

作者： Cheng YUAN Shiming zhang Jiujun zhang Institute for Sustainable Energy/College of Sciences Shanghai UniversityShanghai 200444China

Platinum(Pt)-based materials are still the most efficient and practical catalysts to drive the sluggish kinetics of cathodic oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).However,their catalysis and stability performance still need to be further improved in terms of corrosion of both carbon support and Pt catalyst particles as well as Pt loading *** on the developed synthetic strategies of alloying/nanostructuring Pt particles and modifying/innovating supports in developing conventional Pt-based catalysts,Pt single-atom catalysts(Pt SACs)as the recently burgeoning hot materials with a potential to achieve the maximum utilization of Pt are comprehensively reviewed in this *** design thoughts and synthesis of various isolated,alloyed,and nanoparticlecontained Pt SACs are *** single-atomic Pt coordinating with non-metals and alloying with metals as well as the metal-support interactions of Pt single-atoms with carbon/non-carbon supports are emphasized in terms of the ORR activity and stability of the *** advance further research and development of Pt SACs for viable implementation in PEMFCs,various technical challenges and several potential research directions are outlined.

关键词： oxygen reduction electrocatalysis Pt singleatom catalysts conventional Pt-based catalysts design thoughts and synthesis metal-support interactions