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Long JW Logan MS Rhodes CP Carpenter EE Stroud RM Rolison DR 《Journal of the American Chemical Society》2004,126(51):16879-16889
We have developed crystalline nanoarchitectures of iron oxide that exhibit superparamagnetic behavior while still retaining the desirable bicontinuous pore-solid networks and monolithic nature of an aerogel. Iron oxide aerogels are initially produced in an X-ray-amorphous, high-surface-area form, by adapting recently established sol-gel methods using Fe(III) salts and epoxide-based proton scavengers. Controlled temperature/atmosphere treatments convert the as-prepared iron oxide aerogels into nanocrystalline forms with the inverse spinel structure. As a function of the bathing gas, treatment temperature, and treatment history, these nanocrystalline forms can be reversibly tuned to predominantly exhibit either Fe(3)O(4) (magnetite) or gamma-Fe(2)O(3) (maghemite) phases, as verified by electron microscopy, X-ray and electron diffraction, microprobe Raman spectroscopy, and magnetic analysis. Peak deconvolution of the Raman-active Fe-O bands yields valuable information on the local structure and vacancy content of the various aerogel forms, and facilitates the differentiation of Fe(3)O(4) and gamma-Fe(2)O(3) components, which are difficult to assign using only diffraction methods. These nanocrystalline, magnetic forms retain the inherent characteristics of aerogels, including high surface area (>140 m(2) g(-1)), through-connected porosity concentrated in the mesopore size range (2-50 nm), and nanoscale particle sizes (7-18 nm). On the basis of this synthetic and processing protocol, we produce multifunctional nanostructured materials with effective control of the pore-solid architecture, the nanocrystalline phase, and subsequent magnetic properties. 相似文献
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应用原子吸收光谱法测定了内蒙古地产的笃斯茎、叶中的Cu,Fe,Zn,Mn,Ca,Mg等六种人体必需微量元素及宏量元素的含量。从而为评价笃斯的品质及其药理、药效提供了具有一定价值的数据。 相似文献
14.
Abstract Computer simulation studies of the energy distribution of transmitted ions such as alpha-particles, He-, and B-ions through crystalline silicon, using the enhanced binary-collision cascade simulator MARLOWE, will be reviewed. The enhancement includes an additional electronic-energy loss (EEL) model which takes into account explicitly both the target electron density variation via the structure factors and the electron density of the projectile. Investigations of the stopping power for He ions and protons in silicon, at intermediate- and high-energies, based on the adapted EEL model and a velocity-dependent effective charge will be presented. The overall agreement between the calculated and experimentally determined stopping power data and the simulated and measured transmission spectra will be demonstrated. Effects of energy-loss straggling, core-electron contribution to the energy loss at high-energies and charge-state effects at low energies on the transmission spectra will also be discussed. 相似文献
15.
Liang‐Jin Xu Sujin Lee Xinsong Lin Logan Ledbetter Michael Worku Haoran Lin Chenkun Zhou He Liu Anna Plaviak Biwu Ma 《Angewandte Chemie (International ed. in English)》2020,59(33):14120-14123
Zero‐dimensional (0D) organic metal halide hybrids, in which organic and metal halide ions cocrystallize to form neutral species, are a promising platform for the development of multifunctional crystalline materials. Herein we report the design, synthesis, and characterization of a ternary 0D organic metal halide hybrid, (HMTA)4PbMn0.69Sn0.31Br8, in which the organic cation N‐benzylhexamethylenetetrammonium (HMTA+, C13H19N4+) cocrystallizes with PbBr42?, MnBr42?, and SnBr42?. The wide band gap of the organic cation and distinct optical characteristics of the three metal bromide anions enabled the single‐crystalline “host–guest” system to exhibit emissions from multiple “guest” metal halide species simultaneously. The combination of these emissions led to near‐perfect white emission with a photoluminescence quantum efficiency of around 73 %. Owing to distinct excitations of the three metal halide species, warm‐ to cool‐white emissions could be generated by controlling the excitation wavelength. 相似文献
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Wang F Weidt S Xu J Mackay CL Langridge-Smith PR Sadler PJ 《Journal of the American Society for Mass Spectrometry》2008,19(4):544-549
Reactions of the anticancer complex [(eta(6)-bip)Ru(en)Cl](+) (where bip is biphenyl and en is ethylenediamine) with the tripeptide glutathione (gamma-L-Glu-L-Cys-Gly; GSH), the abundant intracellular thiol, in aqueous solution give rise to two ruthenium cluster complexes, which could not be identified by electrospray mass spectrometry (ESI-MS) using a quadrupole mass analyzer. Here we use Fourier transform ion cyclotron mass spectrometry (nanoLC-FT-ICR MS) to identify the clusters separated by nanoscale liquid chromatography as the tetranuclear complex [{(eta(6)-bip)Ru(GSO(2))}(4)](2-) (2) and dinuclear complex [{(eta(6)-bip)Ru(GSO(2))(2)}(2)](8-) (3) containing glutathione sulfinate (GSO(2)) ligands. Use of (18)OH(2) showed that oxygen from water can readily be incorporated into the oxidized glutathione ligands. These data illustrate the power of high-resolution MS for identifying highly charged multinuclear complexes and elucidating novel reaction pathways for metallodrugs, including ligand-based redox reactions. 相似文献
18.
采用普通溶液法合成了配合物[Zn(eiqnthz)_2]·DMF(1)和[Zn3(piqnthz)_2Cl_2]·2H_2O(2)(Heiqnthz=N,N′-乙酰异喹啉甲酰肼,H2piqnthz=N,N′-丙酰异喹啉甲酰肼)。通过X射线单晶衍射分析、X射线粉末衍射分析、红外光谱分析、热重分析以及荧光光谱分析等分析方法对2个配合物进行结构测定和性质表征。结构分析表明配合物1是单核结构,单斜晶系,空间群为C2/c,锌离子周围有4个氮原子和2个氧原子与之配位,形成一个畸变的N4O2八面体构型。配合物2属于单斜晶系,C2/c空间群,三核结构。中心原子Zn(1)、Zn(2)、Zn(3)均为5配位,Zn(1)、Zn(3)位于分子两端并且是变形四角锥配位构型,Zn(2)位于中间形成三角双锥配位构型,整体呈V字型。荧光分析表明Heiqnthz、H2piqnthz与锌(Ⅱ)离子配位后其荧光都发生较大的红移。 相似文献
19.
LIU Yan-Ping CHEN Zhao-Yang BA Wei-Zhen FAN Yan-Wei DU Yan-Zhao PAN Shi-Lie GUO Qi 《中国物理C(英文版)》2008,32(5)
The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity.Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-acoess and hazardous.In addition.optical fiber dosimeters are immune to electrical and radio-frequency interference.In this paper,a novel remote optical fiber radiation dosimeter is described.The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL.The measuring range of the dosimeter is from 0.1 to 100 Gy.The equipment is relatively simple and small in size,and has low power consumption.This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. 相似文献
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