EXAFS
EXAFS的相关文献在1983年到2022年内共计222篇,主要集中在化学、化学工业、物理学
等领域,其中期刊论文207篇、会议论文7篇、专利文献8篇;相关期刊79种,包括中国科学技术大学学报、无机材料学报、高等学校化学学报等;
相关会议6种,包括2006全国荷电粒子源、粒子束学术会议、中国化学会2002年学术会议、中国颗粒学会2002年年会暨海峡两岸颗粒技术研讨会等;EXAFS的相关文献由427位作者贡献,包括胡天斗、等、谢亚宁等。
EXAFS
-研究学者
- 胡天斗
- 等
- 谢亚宁
- 刘涛
- 孟明
- 伏义路
- 韦世强
- 姜明
- 张静
- 卞国柱
- 陶冶
- 魏正贵
- 沈百荣
- 潘纲
- 赵贵文
- 陆坤权
- 刘振林
- 吴忠华
- 寇元
- 巨新
- 李忠瑞
- 李贤良
- 洪法水
- 赵雅琴
- 吴自玉
- 夏定国
- 张东明
- 徐丽丽
- 徐勇
- 杨凌飞
- 石磊
- 秦延文
- 马礼敦
- 储旺盛
- 吉文斌
- 吕冈
- 吴瑾光
- 张桂林
- 戚泽明
- 方志刚
- 施朝淑
- 林奇生
- 段永恒
- 汪夏燕
- 罗金勇
- 范康年
- 邓景发
- 鲍骏
- LinGuo
- 何卓然
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Dong-Ho Kang;
Yong-Jun Park;
Yun-Sung Jeon;
Nam-Gyu Park
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摘要:
Perovskite solar cells (PSCs) employing formamidinium lead iodide (FAPbI_(3)) have shown high efficiency.However,operational stability has been issued due to phase instability of α phase FAPbI_(3) at ambient temperature.Excess precursors in the perovskite precursor solution has been proposed to improve not only power conversion efficiency (PCE) but also device stability.Nevertheless,there is a controversial issue on the beneficial effect on PCE and/or stability between excess FAI and excess PbI_(2).We report here extended X-ray absorption fine structure (EXAFS) of FAPbI_(3) to study local structural change and explain the effect of excess precursors on photovoltaic performance and stability.Perovskite films prepared from the precursor solution with excess PbI_(2)shows better stability than those from the one with excess FAI,despite similar PCE.A rapid phase transition from α phase to non-perovskite δ phase is observed from the perovskite film formed by excess FAI.Furthermore,the (Pb-I) bond distance evaluated by the Pb L_(III)-edge EXAFS study is increased by excess FAI,which is responsible for the phase transition and poor device stability.This work can provide important insight into local structure-stability relation in the FAPbI_(3)-based PSCs.
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Minmin Wang;
Min Li;
Yilin Zhao;
Naiyou Shi;
Hui Zhang;
Yuxue Zhao;
Yaru Zhang;
Haoran Zhang;
Wenhong Wang;
Kaian Sun;
Yuan Pan;
Shoujie Liu;
Houyu Zhu;
Wenyue Guo;
Yanpeng Li;
Yunqi Liu;
Chenguang Liu
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摘要:
The development of low-cost, efficient, and high atomic economy electrocatalysts for hydrogen evolution reaction(HER) in the entire p H range for sustainable hydrogen production is of great importance but still challenging. Herein, we synthesize a highly dispersed N-doped carbon frames(NCFs) anchored with Co single atoms(SAs) and Co nanoparticles(NPs) catalyst by a doping-adsorption-pyrolysis strategy for electrocatalytic hydrogen evolution. The Co SAs-Co NPs/NCFs catalyst exhibits an excellent HER activity with small overpotential, low Tafel slope, high turnover frequency as well as remarkable stability. It also exhibits a superior HER performance in the entire p H range. Combining with experimental and theoretical calculation, we find that Co SAs with Co-N_(3) coordination structure and Co NPs have a strong interaction for promoting synergistic HER electrocatalytic process. The H_(2)O molecule is easily activated and dissociated on Co NPs, while the generated H^(*) is easily adsorbed on Co SAs for HER, which makes the Co SAs-Co NPs/NCFs catalyst exhibit more suitable H adsorption strength and more conducive to the activation and dissociation of H_(2)O molecules. This work not only proposes a novel idea for constructing coupling catalyst with atomic-level precision, but also provides strong reference for the development of high-efficiency HER electrocatalysts for practical application.
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吴涵玉1;
赵晓岚1;
王威1;
何碧红1;
耿榕悦1;
范桥辉1
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摘要:
作为铀核裂变过程中重要的裂变产物,放射性铯(radiocesium, RCs)是高放废物地质处置中重点关注的核素之一.北山花岗岩与RCs相互作用的微观机制研究对于我国高放废物深地质处置库的性能和安全评价至关重要.本文结合批式实验、电子探针显微分析(EPMA)、同步辐射扩展边X射线吸收精细结构(EXAFS)和微区X射线荧光(μ-XRF)光谱技术,系统研究了不同环境条件下北山花岗岩与Cs(Ⅰ)相互作用的微观机制. EPMA和μ-XRF表明黑云母和长石类矿物是控制北山花岗岩阻滞RCs迁移的主控矿物. EXAFS光谱证明了Cs(Ⅰ)在北山花岗岩和长石类矿物表面的吸附以外层络合作用为主,且在黑云母表面上的内层络合作用较前者显著增大.尽管长石类矿物对Cs(Ⅰ)的固定能力弱于黑云母,但北山花岗岩中长石类矿物的含量较高(约占70%),因此其对Cs(Ⅰ)在北山花岗岩表面吸附的影响亦不可忽视. GAM (general adsorption model)模型能够定量地描述和预测Cs(Ⅰ)在北山花岗岩上的吸附-解吸行为,具有较高盐度的地下水可在一定程度上抑制北山花岗岩对Cs(Ⅰ)的吸附作用;但北山花岗岩上的楔形位点(FES)仍能有效固定痕量RCs,且受北山地下水的盐度和组成离子影响较小.
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Gora Dieye;
Sameh I. Ahmed;
Abdou C. Wade;
Djibril Diop
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摘要:
Negative thermal expansion of gallium arsenide has been investigated through temperature dependent Extended X-ray Absorption Fine Structure (EXAFS) measurements. The bond thermal expansion coefficient αbond has been evaluated and compared to negative expansion coefficient αtens due to tension effects. The overall thermal expansion coefficient is the sum?of?αbond?and αtens. Below 60 K, αtens is greater than αbond? yielding to a negative expansion in this temperature region. Tension effects are progressively overcome by the stretching effects in the region 60 - 300 K. The asymmetry of nearest neighbors distribution is not negligible since the gaussian approximation underestimates the bond expansion by about 0.00426 Å. This error decreases when the temperature is lowered. The accuracy in the thermal expansion evaluation and the connection between third cumulant and thermal expansion are discussed.
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杨春莉;
张生栋
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摘要:
This work apply in situ extended X-ray absorption fine structure (EXAFS)to reveal sorption speciation of Np (Ⅴ)on synthetic lepidocrocite (γ-FeOOH ).Np LⅢ-edge EXAFS analysis shows that Np (Ⅴ)is absorbed on γ-FeOOH as neptunyl ion,with no observations of multinuclear surface complexes or surface precipitates.The Fourier trans-form(FT)magnitude of the EXAFS also shows an obvious peak feature at about 3 Å(1 Å=0.1 nm),that can be attributed to a Np-Fe scattering path,consistent with the formation of an inner sphere Np (Ⅴ)-lepidocrocite surface complex. The EXAFS FT results were compared between Np(Ⅴ)speciation on difference iron mineral phases with similar composi-tions.However,it remains a question whether or not a Np-C coordination exists,indicating the possible presence of Np(Ⅴ)/carbonate species on the lepidocrocite surface.Additional studies are needed,particularly well-designed EXAFS studies,to answer this question and verify the identity of the surface complex.%本工作采用原位扩展 X 射线吸收精细结构(EXAFS)能谱首次揭示了 Np (Ⅴ)吸附于合成纤铁矿(γ-FeOOH)表面的化学形态。Np LⅢ边 EXAFS分析结果显示 Np(Ⅴ)以五价镎酰离子吸附于γ-FeOOH,未发现多核络合物与表面沉淀。傅里叶转化结果在约3Å(1Å=0.1 nm )附近的能峰可归于 Np-Fe配位层,证明了 Np(Ⅴ)-γ-FeOOH 形成了内层吸附的单一形态表面络合物。所得分析结果与 Np(Ⅴ)在相似构成的含铁矿物上的吸附形态结果进行了比较,进一步确认了 Np-Fe、Np-O 等关键配位层的存在。然而,还需要更多设计良好的EXAFS实验来确认是否存在 Np-C配位层,以确认纤铁矿界面是否存在 Np碳酸根表面络合物。
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曹梦雄;
刘昊;
王海欧;
张运;
谭伟石;
时阳光
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摘要:
通过甩带快淬法制备三元合金(Fe0.81Ga0.19)100-xBx(Fe-Ga-B)和(Fe0.81Ga0.19)100-xInx (Fe-Ga-ln)薄带样品,并对Fe-Ga-B合金样品进行热处理.通过高分辨X射线衍射(HRXRD)和扩展X射线吸收精细结构谱(EXAFS)技术表征薄带的微观结构,利用振动样品磁强计和标准电阻应变仪测量了样品的磁性及饱和磁致伸缩系数.研究表明,有序的L12相降低了(Fe0.81Ga0.19)98B2样品的磁致伸缩系数.B原子添加形成的Fe2B相和modified-DO3相有利于提高Fe-Ga合金的磁致伸缩系数.但Fe2B相的饱和磁化强度小于A2相,饱和磁场却远大于A2相,因此随着B含量的增加,Fe-Ga-B薄带的饱和磁化强度逐渐减小,矫顽力逐渐增加.合金中形成的非磁性富In相使得In掺杂Fe-Ga-ln合金的磁致伸缩系数和饱和磁化强度均减小.非磁性富In相使晶格产生畸变,减弱了磁弹性效应,并且抑制了磁畴的运动,从而明显地减小了Fe-Ga带材样品的磁致伸缩系数以及饱和磁化强度,提高了Fe-Ga合金的矫顽力.
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周瀚洋;
于天麟;
敖银勇;
彭静;
翟茂林
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摘要:
二环己基-18-冠-6(DCH18C6)可以有效地从高放废液中分离90Sr,对于减小放射性废物的危害和实现高放废物的减容有重要意义.由于在实际应用中DCH18C6处于射线照射下,其结构可能会被破坏并引起络合能力的变化,因此有必要对该配合物的辐射稳定性进行研究.本文合成了Sr(NO3)2∙DCH18C6配合物晶体,并通过单晶X射线衍射(XRD)与扩展X射线吸收精细结构谱(EXAFS)等方法进行了表征,确定Sr2+与周围氧原子的配位数为10, Sr-O平均键长约为0.268 nm/0.266 nm (XRD/EXAFS).配位原子来自DCH18C6的六个氧原子以及两个作为双齿配体的硝酸根的四个氧原子.对该配合物晶体在空气中进行γ辐照, EXAFS结果表明吸收剂量为400 kGy时, Sr-O键长及配位数没有发生变化,配位结构没有被破坏,具有很好的耐辐照稳定性.显微红外光谱(Micro-FTIR)结果进一步证明辐照后冠醚环的部分C-H键氧化为羟基或羰基,但并不影响DCH18C6与Sr2+的配位结构.%Dicyclohexano-18-crown-6 ether (DCH18C6) is an efficient extractant for the removal of 90Sr from liquid radioactive waste. Because the structure and extractability of DCH18C6 might be affected by radiation during practical application, it is necessary to investigate the radiation stability of the complex of Sr2+with DCH18C6. In this work, a single crystal of Sr(NO3)2∙DCH18C6 complex was synthesized and characterized by X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The coordination number of Sr2+proved to be 10, including six crown ether O atoms and four O atoms from two bidentate nitrate groups. The average Sr-O bond length is 0.268 nm or 0.266 nm, as determined by XRD or EXAFS, respectively. EXAFS spectra proved that the coordination number and the Sr-O bond length of the complex were slightly affected by irradiation for 400 kGy. Although the micro-Fourier-transform infrared spectra indicated that some C-H bonds were oxidized to hydroxyl or carbonyl, the coordination shel of Sr2+and DCH18C6 was not damaged, indicating good radiation stability of the Sr(NO3)2∙DCH18C6 complex.
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