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941.
PengXiang Zhang GuFan Yin YuYan Wang Bin Cui Feng Pan Cheng Song 《中国科学:物理学 力学 天文学(英文版)》2016,59(8):687511
Manipulation of antiferromagnetic (AFM) spins by electrical means is on great demand to develop the AFM spintronics with low power consumption. Here we report a reversible electrical control of antiferromagnetic moments of FeMn up to 15 nm, using an ionic liquid to exert a substantial electric-field effect. The manipulation is demonstrated by the modulation of exchange spring in [Co/Pt]/FeMn system, where AFM moments in FeMn pin the magnetization rotation of Co/Pt. By carrier injection or extraction, the magnetic anisotropy of the top layer in FeMn is modulated to influence the whole exchange spring and then passes its influence to the [Co/Pt]/FeMn interface, through a distance up to the length of exchange spring that fully screens electric field. Comparing FeMn to IrMn, despite the opposite dependence of exchange bias on gate voltages, the same correlation between carrier density and exchange spring stiffness is demonstrated. Besides the fundamental significance of modulating the spin structures in metallic AFM via all-electrical fashion, the present finding would advance the development of low-power-consumption AFM spintronics. 相似文献
942.
Zhao Y Slepkov AD Akoto CO McDonald R Hegmann FA Tykwinski RR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,11(1):321-329
Monodisperse, cross-conjugated perphenylated iso-polydiacetylene (iso-PDA) oligomers, ranging from monomer 15 to pentadecamer 25, have been synthesized by using a palladium-catalyzed cross-coupling protocol. Structural characteristics elucidated by X-ray crystallographic analysis demonstrate a non-planar backbone conformation for the oligomers due to the steric interactions between alkylidene phenyl groups. The electronic absorption spectra of the oligomers show a slight red-shift of the maximum absorption wavelength as the chain length increases from dimer 17 b to pentadecamer 25, a trend that has saturated by the stage of nonamer 22. Fluorescence spectroscopy confirms that the pendent phenyl groups present on the oligomer framework enhance emission, and the relative emission intensity consistently increases as a function of chain length n. The molecular third-order nonlinearities, gamma, for this oligomer series have been measured via differential optical Kerr effect (DOKE) detection and show a superlinear increase as a function of the oligomer chain length n. Molecular modeling and spectroscopic studies suggest that iso-PDA oligomers (n>7) adopt a coiled, helical conformation in solution. 相似文献
943.
耐盐性聚丙烯酸盐类高吸水树脂的制备 总被引:20,自引:0,他引:20
耐盐性聚丙烯酸盐类高吸水树脂的制备宋彦凤,崔占臣,陈欣芳(吉林大学材料科学系长春130023)关键词丙烯酸钠,丙烯酰胺,丙烯酸羟乙酯,共聚物,吸水树脂,耐酸性高吸水树脂是一种应用比较广的功能性高分子材料[1~5].它的吸水率可高达几百倍乃至几千倍。但... 相似文献
944.
本文对微型管状离子选择电极在流动条件下的电化学特征进行了研究,并设计了新的集成微管路离子选择以电极功能块。用此微型装置测定了土壤、血清、水和药物中的K~+、Na~+、pH、Cl~-、F~-、阿托品、东茛菪碱,并和各种标准方法作了比较,获得满意分析结果。 相似文献
945.
报导了采用基于室温脉冲量子级联激光器的脉内光谱检测技术,利用中心波长为1904 cm-1的量子级联激光器,在实验室对NO气体样品进行检测的研究结果. 针对单线直接吸收光谱反演算法进行了研究,介绍了基线拟合的最小二乘算法以获取其吸光度,根据HITRAN数据库中相应吸收谱线的吸收线强,采用扫描积分实现了气体浓度的反演,避免了标气标定造成的误差及污染;通过拟合残差分析得到了系统的检测限,达到34×10-6 m.
关键词:
量子级联激光器
中红外
多项式拟合
扫描积分 相似文献
946.
947.
948.
Iridium(III) Complexes Bearing Pyrene‐Functionalized 1,10‐Phenanthroline Ligands as Highly Efficient Sensitizers for Triplet–Triplet Annihilation Upconversion 下载免费PDF全文
Yue Lu Junsi Wang Dr. Niamh McGoldrick Xiaoneng Cui Prof. Dr. Jianzhang Zhao Colin Caverly Dr. Brendan Twamley Dr. Gearoid M. Ó Máille Bryan Irwin Robert Conway‐Kenny Prof. Dr. Sylvia M. Draper 《Angewandte Chemie (International ed. in English)》2016,55(47):14688-14692
“Chemistry‐on‐the‐complex” synthetic methods have allowed the selective addition of 1‐ethynylpyrene appendages to the 3‐, 5‐, 3,8‐ and 5,6‐positions of IrIII‐coordinated 1,10‐phenanthroline via Sonogashira cross‐coupling. The resulting suite of complexes has given rise to the first rationalization of their absorption and emission properties as a function of the number and position of the pyrene moieties. Strong absorption in the visible region (e.g. 3,8‐substituted Ir‐3 : λabs=481 nm, ?=52 400 m ?1 cm?1) and long‐lived triplet excited states (e.g. 5‐substituted Ir‐2 : τT=367.7 μs) were observed for the complexes in deaerated CH2Cl2. On testing the series as triplet sensitizers for triplet–triplet annihilation upconversion, those IrIII complexes bearing pyrenyl appendages at the 3‐ and 3,8‐positions ( Ir‐1 , Ir‐3 ) were found to give optimal upconversion quantum yields (30.2 % and 31.6 % respectively). 相似文献
949.
以碳纳米管(CNT)作为低铂载量膜电极(CCM)催化层(0.1 mgPt·cm-2)添加剂,研究了CNT的添加方式对催化层微观结构以及膜电极性能的影响.结果表明,与常规低铂载量催化层相比,在其表面喷涂一层CNT或将CNT均匀分散到Pt/C催化层中均有利于提升低铂载量膜电极的输出性能,在70℃和100%相对湿度条件下最高输出功率比常规低铂载量膜电极的0.522 W·cm-2分别提升了22.4%和60.0%,并且均匀分散添加方式优于分层添加方式.其原因在于分层添加CNT后改善了低铂催化层和气体扩散层之间的接触界面,降低了催化层与扩散层间的接触电阻,而均匀分散添加方式除了可降低界面接触电阻外,还显著改善了低铂催化层中的气体传输,大幅提升了Pt催化剂的利用效率,使得膜电极电化学反应电阻明显降低.进一步对均匀分散添加方式中CNT的载量进行优化,表明CNT添加量为37.5 μg·cm-2时电池输出性能最佳,70℃和100%相对湿度条件下的最大输出功率达到0.91 W·cm-2.本研究工作表明,将CNT均匀分散添加到催化层中是一种有效提升低铂载量膜电极性能的方法. 相似文献
950.
Yating Liu Yunhai Liu Xiaohong Cao Rong Hua Youqun Wang Cui Pang Ming Hua Xiaoyan Li 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):231-239
The cross-linked chitosan (CS) gels synthesized by using glutaraldehyde (GLA), epichlorohydrin (EC), and ethylene glycol diglycidyl
ether (EGDE) as cross-linkers respectively were used to investigate the adsorption of U(VI) ions in an aqueous solution. The
pure chitosan (PCS) and the cross-linked chitosan gels were characterized by FTIR and SEM analysis. The kinetic, thermodynamic
adsorption and adsorption isotherms of U(VI) ions onto unmodified and modified cross-linked chitosan were studied in a batch
adsorption experiments. The effect of pH, contact time and temperature on the adsorption capacity were also carried out. At
the optimum pH, the maximum adsorbed amount of PCS, GLACS, ECCS and EGDECS were 483.05, 147.05, 344.83 and 67.56 mg/g, respectively.
The uranium (VI) adsorption process of PCS and ECCS followed better with pseudo-second-order kinetic model, while GLACS and
EGDECS followed pseudo-first-order kinetic model well. The results obtained from the equilibrium isotherms adsorption studied
of U(VI) ions were analyzed in two adsorption models, namely, Langmuir and Freundlich isothms models, the results showed that
the Langmuir isotherm had better conformity to the equilibrium data. The thermodynamic parameters such as enthalpy (ΔHo), entropy (ΔSo), and Gibbs free energy (ΔGo) showed that the adsorption process was both spontaneous and endothermic. 相似文献