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SOLID-STATE variable-temperature NMR STUDY ON THE PHASE SEPARATION OF POLYETHER POLYURETHANE ZWITTERIONOMERS

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Chinese Journal of Polymer Science 1994年第4期12卷 302-308页

作者：杨光陈群王源身杨昌正邬学文 Analytical Center East China Normal University Shanghai 200062 Department of Chemistry Nanjing University Nanjing 210008 Analytical Center East China Normal University Shanghai 200062

Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments.

关键词： Polyether polyurethane variable temperature Wide-line NMR Phase separation

Effect of Curing Regime on Degree of Al^(3+) Substituting for Si^(4+) in C-S-H Gels of Hardened Portland Cement Pastes

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Journal of Wuhan University of Technology(Materials Science) 2014年第3期29卷 546-552页

作者：胡晨光胡曙光 DING Qingjun FENG Xiaoxin HUANG Xiulin School of Materials Science and Engineering Wuhan University of Technology College of Materials Science and Engineering Hebei United University School of Materials Science and Engineering Hubei University

The effect of curing regime on degree ofAl3＋ substituting for Si^4＋（Al/Si ratio） in C-S-H gels of hardened Portland cement pastes was investigated by 29Si magic angel spinning （MAS） nuclear magnetic resonance （NMR） with deconvolution technique. The curing regimes included the constant temperature （20, 40, 60 and 80 ℃） and variable temperature （simulated internal temperature of mass concrete with 60 ℃ peak）. The results indicate that constant temperature of 20 ℃ is beneficial to substitution ofAl3＋ for Si4＋, and AI/Si ratio changes to be steady after 180 d. The increase of Al/Si ratio at 40 ℃is less than that at 20℃ for 28 d. The other three regimes of high temperature increase Al/Si ratio only before 3 d, on the contrary to that from 3 to 28 d. However, the 20 ℃ curing stage from 28 to 180 d at variable temperature regime, is beneficial to the increase of AI/Si ratio which is still lower than that at constant temperature regime of 20 ℃ for the same age. A nonlinear relation exists between the Al/Si ratio and temperature variation or mean chain length （MCL） of C-S-H gels, furthermore, the amount ofAl3＋ which can occupy the bridging tetrahedra sites in C-S-H structure is insufficient in hardened Portland cement pastes.

关键词： constant temperature variable temperature degree of Al3+ substituting for Si4+ C-S-H hardened cement pastes

Charge carrier dynamics in different crystal phases of CH_(3)NH_(3)PbI_(3)perovskite

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Opto-Electronic Science 2022年第4期1卷 1-10,22-27页

作者： Efthymis Serpetzoglou Ioannis Konidakis George Kourmoulakis Ioanna Demeridou Konstantinos Chatzimanolis Christos Zervos George Kioseoglou Emmanuel Kymakis Emmanuel Stratakis Institute of Electronic Structure and Laser(IESL) Foundation for Research and Technology-Hellas(FORTH)Herakleio 70013Greece Electrical and Computer Engineering Department Hellenic Mediterranean UniversityHerakleio 71004Greece Department of Materials Science and Technology University of CreteHerakleio 70013Greece Department of Physics University of CreteHerakleio 70013Greece.

Despite that organic-inorganic lead halide perovskites have attracted enormous scientific attention for energy conversion applications over the recent years,the influence of temperature and the type of the employed hole transport layer(HTL)on the charge carrier dynamics and recombination processes in perovskite photovoltaic devices is still largely *** particular,significant knowledge is missing on how these crucial parameters for radiative and non-radiative recombinations,as well as for efficient charge extraction vary among different perovskite crystalline phases that are induced by temperature ***,we perform micro photoluminescence(pPL)and ultrafast time resolved transient absorption spectroscopy(TAS)in Glass/Perovskite and two dierent Glass/ITO/HTL/Perovskite configurations at temperatures below room temperature,in order to probe the charge carrier dynamics of different perovskite crystalline phases,while considering also the effect of the employed HTL ***,CH_(3)NH_(3)Pbb films were deposited on Glass,PEDOT:PSS and PTAA polymers,and the developed Glass/CH_(3)NH_(3)PbI_(3)and Glass/ITO/HTL/CH_(3)NH_(3)PbI_(3)architectures were studied from 85 K up to 215 K in order to explore the charge extraction dynamics of the CH_(3)NH_(3)PbI_(3)orthorhombic and tetragonal crystalline *** is observed an unusual blueshift of the bandgap with temperature and the dual emission at temperature below of 100 K and also,that the charge carrier dynamics,as expressed by hole injection times and free carrier recombination rates,are strongly depended on the actual pervoskite crystal phase,as well as,from the selected hole transport material.

关键词： transient absorption spectroscopy p-photoluminescence variable temperature perovskite crystalline phases hole transport layer charge carrier dynamics

A NOVEL METHOD FOR STUDYING THE EFFECT OF temperature ARIATIONS ON THE DEVELOPMENT RATE OF INSECTS

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A NOVEL METHOD FOR STUDYING THE EFFECT OF TEMPERATURE ARIATI...