Structure/property relationships of active sites in disordered (amorphous/nanodomain) materials and single crystals

无序（无定形/纳米域）材料和单晶中活性位点的结构/性质关系

• 批准号: 4485-2007
• 负责人: Misra, Sushil
• 金额: $ 1.12万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=363071
• 关键词: Structure; property; relationships; active; sites

Magnetic properties of materials of significant interest in biology, medicine, and industry will be studied by multi-frequency continuous-wave (CW) and pulsed electron magnetic resonance (EMR) techniques, using paramagnetic centres as probes at active sites in these materials. The EMR technique is based on the same principle as that of MRI (Magetic resonance imaging) technique used in hospitals.   1. Multifrequency CW EMR of active sites.   The CW EMR measurements will be carried out in the temperature interval -271 C to +25 C at microwave frequencies in the 9.0 to 350 GHz range. We will measure: 1A. single crystals of rare-earth silicon oxides Y2SiO5 and La2Si2O7  doped with paramagentic ions; 1B. Amorphous materials:(i) Nanodomains: a) Dilute magnetic semiconductors (DMS).  These are oxide materials doped by cobalt and iron ions; b) Ceramics. (ii) Metalloproteins contining doubly ionized iron and triply ionized manganese ions, of importance in biology and medicine.   2. Pulsed EMR. Theoretical calculations will be carried out, taking into account the dipolar interaction between two nitroxide probes that depends on their distance, of signals for: 2A. 2D-ELDOR (two-dimensional electron-electron double resonance); 2B. DQC (double quantum coherence) and DEER (double electron-electron resonance).     The significances of the proposed research are: (1) The "single-crystals"  will  be developed as lasers, phosphors, and materials to be used as replacement  for silicon dioxide gate dielectrics. (2) The DMS samples have the potential to be developed as (spintronic) mass storage devices in hard disks of computers. (3) Novel insights into metalloproteins of interest in biology and medicine will be acquired by developing a better understanding of the properties of exchange-coupled iron centres in these proteins. (4) The pulsed EMR simulations would be used  for distance measurements in biological systems, a topic on the cutting edge of research, providing clues to blueprints in life in the human genome project.

在生物学、医学和工业中具有重要意义的材料的磁性将通过多频连续波（CW）和脉冲电子磁共振（EMR）技术进行研究，使用顺磁中心作为这些材料活性位点的探针。EMR技术的原理与医院使用的MRI（核磁共振成像）技术相同。1. 活性部位的多频连续波EMR。连续波EMR测量将在-271℃至+25℃的温度区间进行，微波频率在9.0至350 GHz范围内。我们将测量：a .稀土硅氧化物Y2SiO5和La2Si2O7掺杂顺磁离子的单晶；1 b。非晶材料：(i)纳米畴；(a)稀磁性半导体（DMS）。这些是由钴和铁离子掺杂的氧化物材料；b)陶瓷。（二）含有双电离铁离子和三电离锰离子的金属蛋白，在生物学和医学上具有重要意义。2. 脉冲EMR。将进行理论计算，考虑到两个氮氧化物探针之间的偶极相互作用取决于它们的距离，信号为：2A. 2D-ELDOR（二维电子-电子双共振）；2 b。DQC（双量子相干）和DEER（双电子-电子共振）。提出的研究意义在于：(1)“单晶”将被开发为激光器、荧光粉和替代二氧化硅栅极电介质的材料。(2) DMS样品具有在计算机硬盘中作为（自旋电子）大容量存储器件发展的潜力。(3)通过更好地理解这些蛋白质中交换偶联铁中心的性质，将获得对生物学和医学感兴趣的金属蛋白的新见解。(4)脉冲EMR模拟将用于生物系统的距离测量，这是研究的前沿课题，为人类基因组计划中的生命蓝图提供线索。