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Magnetic Resonance Letters 2023年第3期3卷 256-265,I0004页

作者： Bulat Gizatullin Carlos Mattea siegfried stapf Department of Technical Physics II TU IlmenauPO Box 100565Il

Determining the dynamics of adsorbed liquids on nanoporous materials is crucial for a detailed understanding of interactions and processes on the solid-liquid interface in many materials and porous *** of the influence of the presence of paramagnetic species on the surface or within the porous matrices is essential for fundamental studies and industrial processes such as *** resonance methods,such as electron paramagnetic resonance(EPR),nuclear magnetic resonance(NMR)and dynamic nuclear polarization(DNP),are powerful tools to address these questions and to quantify dy-namics,electron-nuclear interaction features and their relation to the physical-chemical parameters of the *** paper presents an NMR study of the dynamics of polar and nonpolar adsorbed liquids,represented by water,n-decane,deuterated water and nonane-d20,on the native silica surface as well as silica modified with vanadyl *** analysis of the frequency dependence of the nuclear spin-lattice relaxation time is carried out by separating the intra-and intermolecular contributions,which were analyzed using reorientations mediated by translational displacements(RMTD)and force-free-hard-sphere(FFHS)models,respectively.

关键词： NMR relaxation Fast field cycling Porous media DNP Porphyrins

Investigation of reinforcement of the modified carbon black from wasted tires by nuclear magnetic resonance

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1440-1446页

作者： ZHOU Jie YANG Yong-rong REN Xiao-hong stapf siegfried UNILAB Research Center for Chemical Reaction Engineering School of Material Science and Chemical Engineering Zhejiang University Hangzhou 310027. China） Institute of Macromolecular Chemistry and Technical Chemistry RWTH-Aachen Worringerweg 1 D-52056 Germany

Pyrolysis has the potential of transforming waste into recyclable products. Pyrolytic carbon black (PCB) is one of the most important products from the pyrolysis of used tires. Techniques for surface modifications of PCB have been developed. One of the most significant applications for modified PCB is to reinforce the rubber matrix to obtain high added values. The transverse relaxation and the chain dynamics of vulcanized rubber networks with PCB and modified PCB were studied and compared with those of the commercial carbon blacks using selective 1H transverse relaxation (T2) experiments and dipolar correlation effect (DCE) experiments on the stimulated echo. Demineralization and coupling agent modification not only intensified the interactions between the modified PCB and the neighboring polyisoprene chains, but also increased the chemical cross-link density of the vulcanized rubber with modified PCB. The mechanical testing of the rubbers with different kinds of carbon blacks showed that the maximum strain of the rubber with modified PCB was improved greatly. The mechanical testing results confirmed the conclusion obtained by nuclear magnetic resonance (NMR). PCB modified by the demineralization and NDZ-105 titanate coupling agent could be used to replace the commercial semi-reinforcing carbon black.

关键词： Pyrolytic carbon black (PCB) Nuclear magnetic resonance (NMR) Relaxation Dipolar correlation effect (DCE) Reinforcement

Dipolar NMR relaxation of adsorbates on surfaces of controlled wettability

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Magnetic Resonance Letters 2023年第3期3卷 220-231,I0003页

作者： siegfried stapf Igor Shikhov Christoph Arns Bulat Gizatullin Carlos Mattea Department of Technical Physics II University of Technology IlmenauPO Box 10056598684IlmenauGermany School of Minerals and Energy Resources Engineering University of New South WalesSydneyNSW2052Australia

In reservoir rocks,the term“ageing”refers to extended exposition to crude oil;a typically water-wet sandstone will then gradually become oil-wet as a consequence of the deposition of insoluble fractions of oil onto the surface *** have been aged artificially by subjecting them to a bitumen solution at elevated temperature in order to achieve comparable surface properties for three different types of rock:Bentheimer,Berea Buff and Liege *** saturated and aromatic model compounds as proxies for crude oil,the nuclear magnetic resonance(NMR)relaxation dispersion in native and aged rocks was compared and correlated to the properties of paramagnetic impurities in these rock *** liquids were found to follow the same trend as deuterated and naturally occurring oil components,suggesting they can be used as suitable tracers for wettability studies since the ^(19)F nucleus is absent in natural *** combining electron paramagnetic resonance(EPR)and dynamic nuclear polarization(DNP)it becomes possible to identify and quantify the origin of the dominating relaxation processes between native and aged rocks,providing an alternative approach to assess wettability in natural rocks.

关键词： Rocks Wettability Relaxometry NMR DNP Oil

Binary fluids in mesoporous materials: Phase separation studied by NMR relaxation and diffusion

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Magnetic Resonance Letters 2023年第2期3卷 108-117,I0003页

作者： siegfried stapf Niklas Siebert Timo Spalek Vincent Hartmann Bulat Gizatullin Carlos Mattea Technische Physik Ⅱ/Polymerphysik Technische Universitat IlmenauD-98684IlmenauGermany

Relaxation and diffusion measurements were carried out on single and binary liquids filling the pore space of controlled porous glass Vycor with an average pore size of about 4 *** dispersion of the longitudinal relaxation time Tr is discussed as a means to identify liquid-surface interaction based on existing models developed for metal-free glass *** addition,the change of T1 and T2 with respect to their bulk values is discussed,in particular T2 serves as a probe for the strength of molecular *** the native glass surface is polar and contains a large amount of hydroxyl groups,a pronounced interaction of polar and protic adsorbate liquids is expected;however,the T dispersion,and the corresponding reduction of T2,are also observed for non-polar liquids such as alkanes and *** liquids are employed for simplifying data analysis in binary systems,but also for separating the respective contributions of intra-and intermolecular interactions to the overall relaxation *** the lack of paramagnetic impurities in the glass material,H and 2H relaxation dispersions of equivalent molecules are frequently found to differ from each other,suggesting intermolecular relaxation mechanisms for the'H *** variation of the T dispersion when comparing single and binary systems gives clear evidence for the preferential adsorption of one of the two liquids,suggesting complete phase separation in several *** of the apparent tortuosity by self-diffusion experiments supports the concept of a local variation of sample composition within the porespace.

关键词： NMR relaxation Fast field cycling Porous media Binary fluids Phase separation

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Editorial

Magnetic Resonance Letters 2023年第2期3卷 87-89页

作者： Ruiliang Bai Xueqian Kong siegfried stapf Wei Wang Fangrong Zong Zhejiang University School of Medicine China. Institute of Translational Medicine Shanghai Jiao Tong UniversityChina Department of Mathematics and Natural Sciences Technische Universitat IlmenauGermany. Department of Chemistry and Chemical Engineering Lanzhou UniversityChina School of artificial intelligence Beijing University of Post and TelecommunicationChina

Porous media are ubiquitous and characterized by a wide range of distinct morphological and topographical properties,often difficult to access by conventional *** a unique technology,magnetic resonance has been applied extensively for several decades to non-invasively characterize the structure,interactions and dynamics of fluids in porous media,as well as these media *** does this via spectroscopy,relaxometry,diffusion,or imaging *** special issue is dedicated to an editorial and a selection of outstanding talks/posters presented at the 15th International Bologna Conference Magnetic Resonance in Porous Media(MRPM15).

关键词： media Porous porous

Phase Structures of Nascent Polyethylene Powder Studied by Wideline Proton NMR

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Chinese Journal of Chemistry 2007年第6期25卷 863-868页

作者：严小伟王靖岱任晓红阳永荣蒋斌波 VODA, Mihai Adrian BERTMER, Marko stapf, siegfried College of Material Science and Chemical Engineering Zhejiang University Hangzhou Zhejiang 310027 China Institute of Technical and Macromolecular Chemistry RWTH Aachen University Worringerweg 1 52074 Aachen Germany

The wideline proton NMR spectra of polyethylene powder samples were analyzed in terms of contributions from three components：（1） a rigid part with immobile chains, （2） a soft region with liquid-like character which produces a Lorentzian contribution to the spectrum, and （3） an intermediate region in which the rotation of methylene groups about C-C bonds is partially hindered. The relative mass fractions as well as chain mobilities varied greatly among samples produced by different polymerization techniques. The NMR crystallinity agreed well with that estimated by WAXD and was much higher than DSC crystallinity, indicating an inclusion of the contribution from a crystalline-amorphous interphase. The crystalline defects in the rigid part could be significantly affected by processing parameters when employing the same type of polymerization technique. The intermediate region in the NMR spectra was analyzed according to the comparison between bimodal high density polyethylene and corresponding linear unimodal one. It was found that the mass fraction of the NMR interphase could be an indication of the percentage of tie molecules between crystalline lamellae and thus may significantly affect the mechanical properties of polymeric material.

关键词： polyethylene powder wideline NMR phase structure

PE100管材料的聚集态结构和性能的固体NMR分析

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维普期刊数据库

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材料研究学报 2008年第2期22卷 157-163页

作者：严小伟历伟任晓红王靖岱阳永荣 siegfried stapf Bernhard Blumich 浙江大学化学工程系化学工程国家重点实验室杭州310027 Institut fur Technische Chemie und Makromolekulare Chemie Rheinisch-Westfalische Technische HochschuleWorringerweg 1D-52056 AachenGermany

PE100管材料基体树脂中界面区的含量比较高(高于10%),而完全无定形区的含量极低.界面区含量表征非晶区中运动部分受阻的链段所占的比重,因而上述结果意味着PE100管材料中非晶区中链段表现出强烈的缠结倾向.界面区的含量(或非晶区的组成... 详细信息

PE100管材料基体树脂中界面区的含量比较高(高于10%),而完全无定形区的含量极低.界面区含量表征非晶区中运动部分受阻的链段所占的比重,因而上述结果意味着PE100管材料中非晶区中链段表现出强烈的缠结倾向.界面区的含量(或非晶区的组成特征)决定了材料的耐慢速裂纹增长性能,而固相区含量则决定了材料的力学强度,两种影响因素的平衡决定了最终管材料的长期使用性能.

关键词：有机高分子材料 PE100管材料固体核磁共振聚集态结构力学性能

The free-electron laser FLASH

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High Power Laser Science and Engineering 2015年第3期3卷 28-40页

作者： siegfried Schreiber Bart Faatz Deutsches Elektronen-Synchrotron

FLASH at DESY, Hamburg, Germany is the first free-electron laser(FEL) operating in the extreme ultraviolet(EUV)and soft x-ray wavelength range. FLASH is a user facility providing femtosecond short pulses with an unprecedented peak and average brilliance, opening new scientific opportunities in many disciplines. The first call for user experiments has been launched in 2005. The FLASH linear accelerator is based on TESLA superconducting technology, providing several thousands of photon pulses per second to user experiments. Probing femtosecond-scale dynamics in atomic and molecular reactions using, for instance, a combination of x-ray and optical pulses in a pump and probe arrangement,as well as single-shot diffraction imaging of biological objects and molecules, are typical experiments performed at the facility. We give an overview of the FLASH facility, and describe the basic principles of the accelerator. Recently,FLASH has been extended by a second undulator beamline(FLASH2) operated in parallel to the first beamline, extending the capacity of the facility by a factor of two.

关键词： bunch compression free-electron laser high-gain FEL process photo injector SASE superconducting accelerator undulator

Finite Element Simulations of Crack Propagation in Al_(2)O_(3)/6061Al Composites

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Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 853-861页

作者： Galina Lasko Ulrich Weber siegfried Schmauder Institut für Materialprüfung Werkstoffkunde und Festigkeitslehre(IMWF)Universitat Stuttgart

In this work, the local fracture initiation behaviour of an Al2O3/6061Al composite is studied numerically. The damage behaviour of the microstructure is evaluated in consideration of the path and the amount of damage as well as the stress-strain performance of the microstructure. The damage behaviour of the ductile matrix has been simulated using the damage parameter D. For the simulation of fracture of the ceramic particles, a normal stress criterion is applied. For the analysis of the damage behaviour of the transition zone between particulate and matrix, both damage models （D parameter and normal stress criteria） are applied in this region. Parameter studies of crack propagation prediction in the Al2O3/6061Al composite on the basis of an Element Elimination technique have been performed for two differently heat-treated variants resulting in different mechanical properties. In addition, residual stress effects on the damage behaviour are examined for various microstructural situations.

关键词： Metal matrix composites Simulation Crack propagation Finite element method Element elimination technique

Cellular precision modulation of JAK1:tailoring therapies for allergic lung inflammation

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Signal Transduction and Targeted Therapy 2024年第7期9卷 2843-2844页

作者： Xiaocheng Yan siegfried Ussar Research Unit Adipocytes&Metabolism(ADM) Helmholtz Diabetes CenterHelmholtz Zentrum MünchenGerman Research Center for Environmental Health GmbH85764 NeuherbergGermany German Center for Diabetes Research(DZD) 85764 NeuherbergGermany

In a recent publication published in Cell,Tamari et *** a previously unrecognized role of JAK1 signaling in vagal sensory neurons regulating the immune response to allergic lung inflammation.1 The authors show that sensory neuromodulation could be an important therapeutic avenue for the treatment of lung *** is now well established that the number of patients suffering from allergic disorders,like those suffering from obesity and the metabolic syndrome,is rapidly increasing world-wide,accelerating the burden on individual health and healthcare ***,basic and clinical researchers urgently need to develop novel therapeutics and approaches to limit or prevent disease development or progression.

关键词： JAK1 allergic lung