Name: high-sensitivity nuclear magnetic resonance at giga-pascal pressures: a new tool for probing electronic and chemical properties of condensed matter under extreme conditions
Uploaded: 2014-10-10T15:00:00.000+00:00
Duration: 8 min 42 s
Description: Watch this Scientific Journal Video about High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extr

This research was funded by the International Research Training Group (IRTG) &#8220;Diffusion in porous Materials&#8221;. We acknowledge the technical support from Gert Klotzsche and stimulating discussions with Steven Reichhardt, Thomas Meissner, Damian Rybicki, Tobias Herzig, Natalya Georgieva, Jonas Kohlrautz, and Michael Jurkutat.

1，安装和6H-SiC的大锥伯勒尔型砧的对齐<ol><li>修正了在安装工具活塞和XY板插入伯勒尔型砧的休息区。 </li><li>确保每个砧坐在稳稳的背板。 </li><li>采用环氧树脂，（ 例如 ，STYCAST 1266），胶砧均向自己的座位上。固化在室温下12小时，或65ºC在炉中2小时。 </li><li>为了有足够的铁砧对齐，用货币供应量M1止动螺钉对齐背板和监控两个砧的并行性。如果被发现的砧块是不平行的，除去环氧树脂和重新启动点1.2处。 </li></ol> 2垫片准备<ol><li>钻头1毫米的孔进入退火铜成为一个芯片（铜98瓦特％，为2％（重量），厚度为0.5mm）的黄铜导销。 </li><li>插入三个长5mm条直径为1毫米的非绝缘铜线插入孔中，这是沿着砧分布，以作为GUIDË引脚的铜要垫片。 </li><li>检查之间的导销和胞体正确接地。通常情况下，约0.1Ω的直流电阻是理想的。改善与少量的导电银的应用。 </li><li>广场上的莫桑石砧顶部的铜成为芯片和关闭的单元格。 </li><li>使用油压机，加压垫片约1/8底尖直径为最大化的工作稳定性。监控用千分尺卡尺压痕的实际厚度。 </li><li>钻适当的直径（底尖直径为½）在压痕中心的孔。 </li><li>中分两个通道进入预凹垫圈。信道应足够深以容纳微线圈的18微米的铜导线。 </li><li>硬化的炉中所制备的衬垫在617 K表示2至3小时。 </li></ol> 3，准备和微线圈的加载<ol><li>采用了一块1毫米铜线的d至馈通在活塞的螺纹它。固定铜线用环氧树脂和根据步骤1.3治愈它。 </li><li>选择锥子（见材料清单），其具有用于将微线圈的所需直径和固定它的一对可旋转的卡盘夹爪之间。 </li><li>胶（ 如与清漆从SCB，见材料清单）的18微米的铜导线的一端上的卡盘爪，同时保持，另一端与旋转的卡盘爪，使得导线被卷绕到锥子。 </li><li>当微线圈是所期望的几何形状，固定金属丝的另一端部上的胶为好。 </li><li>使用稀释的清漆通过在绕组的顶部施加少量固定线圈。 </li><li>使用铁氟龙胶带锥子小心地取出线圈。 </li><li>放置一些环氧树脂（见点1.3），无任何添加剂，在密封垫的频道。 </li><li>将微线圈的样品室内部并固定在引线进入通道。 </li><li>治愈的磐英根据Ÿ树脂步骤1.3。 </li><li>焊料的微线圈的热丝，另一个导销的一个引线。 </li><li>添加一些银导电浆料每个结顶。固化过程通常需要几分钟。 </li><li>用少量环氧树脂密封两个结。 </li><li>治疗根据步骤1.3环氧树脂。 </li><li>现在，检查该线圈的直流电阻的每一步之后。 </li><li>放置在微线圈的样品。要知道，任何不必要的身体接触可能会破坏线圈。 </li><li>加入精细研磨的红宝石粉末样品的压力校准。 </li><li>最后，水灾与适当的压力介质的样品室中。用石蜡油，以确保近静水条件下可达9 GPA。 </li><li>小心合上电池。 </li></ol> 4，应用和监控压力<ol><li>起初，稍微收紧货币供应M3六角沉头螺钉。 </li><li>对于加压固定在台钳细胞。现在，拧紧两个对立的螺丝配对。 </li><li>将加压的细胞在适当的细胞支架。 </li><li>调整单元的位置，以使激光束到达样品室。 </li><li>使用精细调节表聚焦红宝石粉末在激光束。 </li><li>显示器采用相应的光谱仪软件红宝石光致发光光谱。 </li><li>提取在从红宝石R1和R2线所观察到的光谱位移的样品腔的实际压力。 </li><li>平衡加压的细胞至少12小时NMR测量前。 </li></ol> 5，执行NMR实验<ol><li>安装压力盒上典型的核磁共振探头。制造一个机械车间相应的单元格持有人。 </li><li>焊接热丝到探针。检查细胞和探针之间的适当的电接触。 </li><li>现在，执行标准NMR实验。提请注意的事实是，微线圈是版y以所施加的射频功率敏感。 </li></ol>

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	<li>Hemley, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Percy+Bridgman&#180;s+Second+Century.">Percy Bridgman&#180;s Second Century.</a> High Pressure Research. 30 (4), 581-619 (2010).</li><li>Grochala, W., Hoffmann, R., Feng, J., Ashcroft, N. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Chemical+imagination+at+work+in+very+tight+places.">The Chemical imagination at work in very tight places.</a> Angewandte Chemie (International Edition in English). 46 (20), 3620-3642 (2007).</li><li>Ma, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transparent+dense+sodium.">Transparent dense sodium.</a> Nature. 458 (7235), 182-185 (2009).</li><li>Eremets, M. I., Troyan, I. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conductive+dense+hydrogen.">Conductive dense hydrogen.</a> Nat Mater. 10 (12), 927-931 (2011).</li><li>Jayaraman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diamond+anvil+cell+and+high-pressure+physical+investigations.">Diamond anvil cell and high-pressure physical investigations.</a> Rev Mod Phys. 55 (1), 65-108 (1983).</li><li>Bertani, R., Mali, M., Roos, J., Brinkmann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+diamond+anvil+cell+for+high-pressure+NMR+investigations.">A diamond anvil cell for high-pressure NMR investigations.</a> Rev Sci Instrum. 63 (6), 3303 (1992).</li><li>Lee, S. -. H., Luszczynski, K., Norberg, R. E., Conradi, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NMR+in+a+diamond+anvil+cell.">NMR in a diamond anvil cell.</a> Rev Sci Instrum. 58 (3), 415 (1987).</li><li>Lee, S. -. H., Conradi, M. S., Norberg, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+NMR+resonator+for+diamond+anvil+cells.">Improved NMR resonator for diamond anvil cells.</a> Rev Sci Instrum. 63 (7), 3674 (1992).</li><li>Pravica, M. G., Silvera, I. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+magnetic+resonance+in+a+diamond+anvil+cell+at+very+high+pressures.">Nuclear magnetic resonance in a diamond anvil cell at very high pressures.</a> Rev Sci Instrum. 69 (2), 479 (1998).</li><li>Lee, S. -. H., Conradi, M., Norberg, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+motion+in+solid+H2+at+high+pressures.">Molecular motion in solid H2 at high pressures.</a> Phys Rev B. 40 (18), 12492-12498 (1989).</li><li>Vaughan, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Apparatus+for+Magnetic+Measurements+at+High+Pressure.">An Apparatus for Magnetic Measurements at High Pressure.</a> Rev Sci Instrum. 42 (5), 626 (1971).</li><li>Yarger, J. L., Nieman, R. A., Wolf, G. H., Marzke, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Pressure+1H+and+13C+Nuclear+Magnetic+Resonance+in+a+Diamond+Anvil+Cell.">High-Pressure 1H and 13C Nuclear Magnetic Resonance in a Diamond Anvil Cell.</a> Journal of Magnetic Resonance Series A. 114 (2), 255-257 (1995).</li><li>Okuchi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+type+of+nonmagnetic+diamond+anvil+cell+for+nuclear+magnetic+resonance+spectroscopy.">A new type of nonmagnetic diamond anvil cell for nuclear magnetic resonance spectroscopy.</a> Physics of the Earth and Planetary Interiors. , 143-144 (2004).</li><li>Kluthe, S., Markendorf, R., Mali, M., Roos, J., Brinkmann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure-dependent+Knight+shift+in+Na+and+Cs+metal.">Pressure-dependent Knight shift in Na and Cs metal.</a> Phys Rev B. 53 (17), 11369-11375 (1996).</li><li>Graf, D. E., Stillwell, R. L., Purcell, K. M., Tozer, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonmetallic+gasket+and+miniature+plastic+turnbuckle+diamond+anvil+cell+for+pulsed+magnetic+field+studies+at+cryogenic+temperatures.">Nonmetallic gasket and miniature plastic turnbuckle diamond anvil cell for pulsed magnetic field studies at cryogenic temperatures.</a> High Pressure Research. 31 (4), 533-543 (2011).</li><li>Pravica, M., Silvera, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NMR+Study+of+Ortho-Para+Conversion+at+High+Pressure+in+Hydrogen.">NMR Study of Ortho-Para Conversion at High Pressure in Hydrogen.</a> Physical Review Letters. 81 (19), 4180-4183 (1998).</li><li>Haase, J., Goh, S. K., Meissner, T., Alireza, P. L., Rybicki, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+sensitivity+nuclear+magnetic+resonance+probe+for+anvil+cell+pressure+experiments.">High sensitivity nuclear magnetic resonance probe for anvil cell pressure experiments.</a> Rev Sci Instrum. 80 (7), 73905 (2009).</li><li>Meissner, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+Approach+to+High-Pressure+Nuclear+Magnetic+Resonance+with+Anvil+Cells.">New Approach to High-Pressure Nuclear Magnetic Resonance with Anvil Cells.</a> J Low Temp Phys. 159 (1-2), 284-287 (2010).</li><li>Meier, T., Herzig, T., Haase, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moissanite+Anvil+Cell+Design+for+Giga-Pascal+Nuclear+Magnetic+Resonance.">Moissanite Anvil Cell Design for Giga-Pascal Nuclear Magnetic Resonance.</a> Rev Sci Instrum. 85 (4), 43903 (2014).</li><li>Boyer, R. F., Collings, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Materials Properties Handbook: Titanium Alloys. , (1994).</li><li>Xu, J. -. a., Yen, J., Wang, Y., Huang, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh+pressures+in+gem+anvil+cells.">Ultrahigh pressures in gem anvil cells.</a> High Pressure Research. 15 (2), 127-134 (1996).</li><li>Xu, J. -. a., Mao, H. -. k., Hemley, R. J., Hines, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+moissanite+anvil+cell+a+new+tool+for+high-pressure+research.">The moissanite anvil cell a new tool for high-pressure research.</a> J Phys Condens Matter. 14 (44), 11543-11548 (2002).</li><li>Xu, J. -. a., Mao, H. -. k., Hemley, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+gem+anvil+cell+high-pressure+behaviour+of+diamond+and+related+materials.">The gem anvil cell high-pressure behaviour of diamond and related materials.</a> J Phys Condens Matter. 14 (44), 11549-11552 (2002).</li><li>Meissner, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+magnetic+resonance+at+up+to+10.1+GPa+pressure+detects+an+electronic+topological+transition+in+aluminum+metal.">Nuclear magnetic resonance at up to 10.1 GPa pressure detects an electronic topological transition in aluminum metal.</a> J Phys Condens Matter. 26 (1), 15501 (2014).</li><li>Meissner, T., Goh, S. K., Haase, J., Williams, G. r. a. n. t. . V. M., Littlewood, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-pressure+spin+shifts+in+the+pseudogap+regime+of+superconducting+YBa2Cu4O8+as+revealed+by+17O+NMR.">High-pressure spin shifts in the pseudogap regime of superconducting YBa2Cu4O8 as revealed by 17O NMR.</a> Phys Rev B. 83 (22), (2011).</li><li>Goh, S. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+pressure+de+Haas&#8211;van+Alphen+studies+of+Sr2RuO4+using+an+anvil+cell.">High pressure de Haas&#8211;van Alphen studies of Sr2RuO4 using an anvil cell.</a> Current Applied Physics. 8 (3-4), 304-307 (2008).</li><li>Tateiwa, N., Haga, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluations+of+pressure-transmitting+media+for+cryogenic+experiments+with+diamond+anvil+cell.">Evaluations of pressure-transmitting media for cryogenic experiments with diamond anvil cell.</a> Rev Sci Instrum. 80 (12), 123901 (2009).</li><li>Hahn, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin+Echoes.">Spin Echoes.</a> Phys Rev. 80 (4), 580-594 (1950).</li><li>Boehler, R., Ross, M., Boercker, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melting+of+LiF+and+NaCl+to+1+Mbar+Systematics+of+Ionic+Solids+at+Extreme+Conditions.">Melting of LiF and NaCl to 1 Mbar Systematics of Ionic Solids at Extreme Conditions.</a> Physical Review Letters. 78 (24), 4589-4592 (1997).</li><li>Funamori, N., Sato, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cubic+boron+nitride+gasket+for+diamond-anvil+experiments.">A cubic boron nitride gasket for diamond-anvil experiments.</a> Rev Sci Instr. 79 (5), 053903 (2008).</li><li>Forman, R. A., Piermarini, G. J., Barnett, J. D., Block, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure+measurement+made+by+the+utilization+of+ruby+sharp-line+luminscence.">Pressure measurement made by the utilization of ruby sharp-line luminscence.</a> Science. 176 (4032), 284-285 (1972).</li></ol>

The authors have nothing to disclose.

一个新的，有前途的方法，以千兆帕斯卡的压力进行核磁共振被描述。这种方法开启了大门，各种各样的NMR实验，由于其出色的灵敏度和分辨率。然而，在该协议部分中所述的几个步骤是至关重​​要的实验的结果。特别是，在制备微线圈和其在所述Cu-成为垫圈固定是非常困难的，并且需要一定的经验。在下文中，一些重要的提示被给出，这将有助于该技术的第一次成功应用。 使用商业阿波罗或布鲁克核磁共振波谱仪固态核磁共振的应用得到了所有提交的数据。磁铁是标准的大口径布鲁克磁体的磁场范围从7.03至17.6 T.简单自制的核磁共振用于标准的核磁共振实验探针进行了改造，以保持砧细胞。 在LAC-TM2的细胞机箱应根据在补充给定的蓝图来制造。特别注意了，为了避免任何种类的间隙要支付给该活塞的制造和在单元的外壳及其对应的导管。通常情况下，较好的大于10微米的精度有一定要求，以确保在压力单元的负载下有足够的工作稳定性。良好的机加工车间可以达到0.01〜0.015毫米的尺寸精度。所需的M4六角埋头螺栓可以被制造为好，或者从专门的公司（ 例如，见材料清单）购买。在整个细胞制剂，可使用非磁性的工具，因为每个污染的铁磁材料将影响实验的结果。因此，使用钛手术刀或玻璃创作钻石雕刻渠道进入铜要垫片时。 在编号3的步骤中，需要为获得最佳结果几个特殊的工具。用于制备微 - 共IL，既可以用于一组卡盘爪或车床。为微线圈的绕组，圆锥形锥子可以使用（通常在直径为180微米至450微米）。对于样品装载，一条线或一个非常尖锐的针应该被采用。需要注意的是线圈的总高度不应超过垫圈的预凹痕的厚度是很重要的。通常情况下，微线圈制成的3至5个圈（使用18微米的铜导线）具有小于100微米的高度，足以为1000μm和800μm的底尖刻砧。关键的是要监控的微线圈的直流电阻在每一步下列步骤3.10。通常，预期的电阻应该在1Ω跨细胞，如果电阻分解为kΩ或连MΩ，细胞必须被打开，并且程序重新启动时，开始在步骤3.1。 应避免射频微线圈的变形。根据经验，人们发现，在上述6 GPA压力吨他的Cu-成为垫片开始变平与压力，减少容易低于50微米的样品孔的高度，以4个以上的变形最微线圈变为相当。如果砧座具有较小的底尖大小是为了达到较高的压力下使用时，所得到的试料室将大大减少体积（从垫圈设计为最大化的工作稳定性的要求而产生）。例如，通过从一对为1mm至0.8mm的底尖砧去，样本量将是约10 NL减少到3 NL和微线圈的匝数会减少从6至图4（若为18μm铜线被使用）。这通常会导致数量级为约一个数量级的降低的信噪比（SNR）。 在这一点上，我们想强调，该垫片材料的选择可能是至关重要的。所引入的铜被密封垫可能无法如以上10GPa的压力，因为该样品腔WIL的上述变形期望适合升最终破坏射频微线圈。另一种垫圈材料可以是铼，它具有高得多的机械强度和非磁性。另一种建立方法被引入由伯勒尔等人 29，其中所述垫圈的内金属区域被置换为金刚石/环氧树脂混合物;其他组30用于立方氮化硼作为垫片材料;为了改善高度到样品腔的直径之比。这种方法被认为是优于以前使用的金属垫片。在这一点上，作者收集与此有前途的技术，它会在其他地方发表了一些经验。 一定的压力运行后的钛螺丝以及艾伦一套钥匙的线程和螺栓会穿脱。因此，他们需要一个机加工车间或修订的完全替代。选择用于该实验的权利压力介质是至关重要的。压力校准步骤4.4，可以很容易地完成用市售光谱仪系统来观察，R 1和R 2线的红宝石粉末的压力引起的变化。关于这个公知技术的进一步信息中给出的文献31。 hydrostaticity的损失是由线宽的R 1和R 2频谱的红宝石光致发光的急剧增加来表示。 1甲醇/乙醇混合物中，这是为了提供静水条件达在10GPa的范围内的压力:最好的结果可以通过使用液态氮，液态惰性气体或4来实现。 该技术的限制，相对于标准的NMR实验，位于任魔角旋转技术的交通不便。这极大地限制了分辨率大约5ppm。在另一方面，在1 H-NMR测量，此刻，不推荐，由于庞大的各种杂散信号的质子所产生dominantl从供环氧树脂和微线圈的聚氨酯绝缘以及大多采用压力传递介质。在这里提到的另一个重要的一点是，每个实验的成功取决于样品固有的自旋松弛时间的设置每个取样时间的长度。由于快速的光谱积累期望以减少总的测量时间，应避免使用具有非常长T 1的样品。 它必须指出，一个1 H-NMR可能与我们的设计可行，由于广泛使用的环氧树脂，清漆，和绝缘导线的用于微线圈。不过，如果对质子实验所需的一个需要通过和 - 大替代含材料1H（或使用2H合成在可能的情况）。 在高静水压力下的所有其他方法进行核磁共振遭受低信噪比，因此相当长所需的数据采集时间，WHICH提供了大量的实验是不可能的。所示的微线圈的办法，克服由螺旋的显着改善填充因数的那些障碍，我们已经表明，核磁共振上高度相关的和不相关的电子系统是可能的。 最后，我们相信，我们的新顶砧技术，代表了现代凝聚态研究的一个重大发展。我们已经表明，这种方法使研究人员能够在压力高达10GPa的进行高灵敏度的NMR实验。第一应用证明砧细胞NMR带给现代材料的电子和化学结构的研究，该功率。

由于在上个世纪初高静水压力凝聚态珀西·布里奇曼的标志性实验，高压物理学领域已经发展迅速1。大量的有趣的现象是已知的下几个GPA 2的压力下发生。此外，凝聚态系统的高压反应已经告诉我们很多关于他们的电子基态和激发态3,4。 不幸的是，技术的凝聚态的千兆帕斯卡压力的电子性质的研究并不多见，与X射线或直流电阻测量一路领先5。特别地，电子或核磁矩与电子自旋（ESR）或核磁共振（NMR）实验中，检测被绑定到几乎不可能在一个典型的高压砧座单元，其中一个需要从检索的信号来实现一个小v通过砧座和密封垫圈olume供奉。 几个小组已尝试通过使用复杂的安排，要解决这个问题，例如，两个分割线对射频（RF）线圈沿砧块6的侧面缠绕;单或双环流发针谐振器7,8; 。甚至分裂铼垫圈作为RF拾取线圈9， 见图1不幸的是，这些方法仍然从低信号对噪声比（SNR）遭遇，限制了实验应用到大- γ核如1 H 10。有兴趣的读者可以称作其它高压谐振电路实验11 - 15。 Pravica和Silvera 16报告后的核磁共振砧细胞与12.8 GPA，谁研究了邻对位氢转换的最高压力。 随着应用核磁共振极大的兴趣研究量子固体的性质，我们集团很感兴趣，有核磁共振可在高压下，也是如此。最后，在2009年它可以证实高灵敏度砧细胞NMR的确是可能的，如果谐振无线电频率（RF）微线圈是在高压腔包围的样品17直接放置。在这样的方法中，NMR灵敏度是由几个数量级的（主要是由于急剧增加填充的RF线圈的因子），其变得更加具有挑战性NMR实验可能的， 例如在粉末样品的提高，17 O NMR高温超导体在长达7 GPA 18。超导这些材料可以通过施加压力大大放大了，现在就可以按照这个过程与当地的电子探头，承诺根本的洞察管理流程。另一实例为核磁共振高压下的功率从出现什么是believ编为常规参考实验:为了测试引入新砧细胞核磁共振，最著名的材料中的一种测定 - 简单的铝金属。随着压力的增加，从人们所期望的自由电子系统的NMR位移的一个意想不到的偏差被发现。增加下压力的反复实验，也表明新的结果确实是可靠的。最后，与带结构的计算然后将其发现的结果是，铝的费米表面，而无法通过计算年前被检测到的拓扑过渡的表现形式，在计算能力低。的调查结果的环境条件推断表明，这种金属的使用几乎无处不在的特性是由这个特殊的电子状态的影响。 为了追求许多不同的应用的特殊设计的砧座单元（前细胞已经从Cavend进口ISH实验室改造核磁共振）已经制定出来。目前，所使用自制的底盘是能够使用对800微米的底尖刻6H-SiC的砧块到达压力高至25京帕。核磁共振实验，成功地进行了高达10.1 GPa时为止。这种新的细胞的NMR性能被证明是优良19。其主要成分是钛铝（6）-Vanadium（4）与超低间隙水平（等级23），提供约800屈服强度MPa 20。由于它的非磁特性（磁化率χ是约5ppm）它是用于在砧座单元机架的适当材料。引入细胞（ 见图2中的所有自制的压腔设计概述）的整体尺寸小到足以放入普通标准孔核磁共振磁体。最小的设计中，LAC-TM1，这是只有20毫米高和1​​7毫米的直径，也符合典型的小，冷孔磁铁（30毫米孔直径）。第lAC-TM2，这是最新的底盘作者设计，使用四个M4内六角沉头螺栓（做出来的相同的合金作为电池机箱）作为压力驱动机构，允许在内部压力的平稳控制（安装在蓝图补充部分）。 通常情况下，金刚石砧使用，以便产生上述为100GPa最高压力。许茂和21 - 23已经证明，莫桑石砧提供高压的研究具有成本效益的替代方案，高达约60 GPA的压力。因此，碳硅石砧块被用于引入GPA NMR方法。最好的结果是用自Charles＆科尔瓦德的砧座部定制大锥6H-SiC的砧块。与这些细胞中，压力达10.1 GPa时使用800微米的底尖刻砧被发现导致非常好的NMR灵敏度。为了进行比较，李等人报道的1 SNR核为1 H NM自来水中的R，而引入微线圈的方法的SNR显示出25的值对于其体积的七分之一，即使在稍微较低的磁场。 有了这项新措施，以高灵敏度压腔核磁共振可以追求的承诺令人兴奋的新洞察现代材料的物理和化学多种应用。然而，一如既往的灵敏度和分辨率最终限制NMR的应用，特别是，如果一个人的爱好有高得多的压力需要小型的底尖大小。然后，人们不仅以优化电池设计具有更小的RF线圈，而且还考虑增加核极化方法。

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high-sensitivity nuclear magnetic resonance at giga-pascal pressures: a new tool for probing electronic and chemical properties of condensed matter under extreme conditions

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe.

图3示出了如何在完全组装压力盒，布线和安装到一个典型的NMR探针样子。在下文中，几个实验进行审查，应使读者能够收集有关的优点和引入的技术的范围广泛的概述。 <img alt="图1" src="/files/ftp_upload/52243/52243fig1highres.jpg" /> 图1:不同的方法适用于高压核磁共振:（一）拆分对线圈围绕砧侧面，以及从Bertani 等铼垫片。 （转载自Bertani 等 4版权所有1992年的权限，AIP出版社有限责任公司）（B）发针谐振器由Lee 等人 。 （转载与权限Lee 等 6版权所有1992年，AIP出版社有限责任公司）（C）Pravica 等 。介绍的方法使用分离垫片连同一圈盖电感的射频耦合线圈。 （转载自Pravica 等 7权限） <a href="https://www.jove.com/files/ftp_upload/52243/52243fig1large.jpg" target="_blank">点击此处查看本图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/52243/52243fig2highres.jpg" /> 图2:各种高中压压腔设计，核磁共振:所有设计单元的底盘由一个简单的活塞缸设置没有与除平面可调锥形砧垫板进一步铁砧对齐机制。的圆筒型电池TM0和TM1特别适合于单晶的NMR研究，其中一个适当的晶体取向可通过沿其对称轴旋转的细胞来实现。所有机架的整体尺寸不超过40毫米，使它们在标准大孔核磁共振磁铁使用。的最小设计尺寸（TM1）使其能够用于即使对于小口径磁铁（总尺寸20毫米×18毫米）。 <img alt="图3" src="/files/ftp_upload/52243/52243fig3highres.jpg" /> 高压区图3（A）照片，以4圈的微线圈充满液态镓样品，宝石粉和传压介质（B）安装LAC-TM1在自制的核磁共振探头。 （三）探头连接微线圈的高压区域的原理接线，见29。 <a href="https://www.jove.com/files/ftp_upload/52243/52243fig3large.jpg" target="_blank">请点击这里查看该图的放大版本。</a> 一）铝粉高达27铝核磁共振至10.1 GPA <stroNG&gt; 24，核磁共振的YBa 17 O 2的Cu 4 O 8到6.4的GPA 25 第一个实验用的卡文迪许实验室的剑桥大学，被广泛用于解哈斯车尔芬测量26铍铜金刚石压腔的设计进行的。小区被准备好用于高灵敏度NMR实验在Leipzig和代表性结果现在将讨论。 在第一组实验中涉及的是被认为是合适的参考化合物的金属铝的调查。两种不同砧细胞被利用，配备有1000微米底尖直径压力达4.2 GPA砧，并与800微米culets砧压力达10.1GPA。对应的微线圈为螺线管以10圈（直径为300μm），和9圈（200微米的直径），并在和0.8mm底尖砧块，分别。绝缘铜导线的直径为15μm。压力细胞加载细碎铝粉末（纯度3N，325目）和小的红宝石芯片用作压力传感器。作为压力传递介质，芫花7373和甘油被用来提供静水条件高达至少为5GPa 27。 NMR测定中的7.03Ť磁场在室温进行，11.75 T和17.6 T（字段相关的测量是必要的，调查谱线增宽机制）。谐振电路的品质因数Q是大约16的所有单元。与章动的实验中，π/ 2的脉冲长度被确定为大约2微秒，在约1瓦的平均RF功率脉冲。这些参数导致的平均射频磁场振幅乙1中的谐振磁墨字符识别邻线圈的关于B 1 =π/（2γN t个π/ 2）= 11公吨（27 A1的旋磁比为6.98∙10 7 RADT -1 -1）。这估计是3只的因子比理论数字越小，B 1 = [（μ0，QP）/（2ωV线圈 ）]½= 35 mT的，并且表明，大多数的RF功率确实驱动铝谐振和良好的灵敏度检测可以预期，以及。例如，在6.3 GPa时1024的信号进行累计，得到令人满意的光谱。具有大约50毫秒的脉冲重复时间，总的测量时间为每光谱仅约1分钟。该班 ​​被引用到水氯化铝样品。 <img alt="图4" src="/files/ftp_upload/52243/52243fig4highres.jpg" /> 图4的27 Al核磁共振对金属铝p更旧的:（一）取得的频谱高达10.1 GPA;（二）观察总线宽（红色方块）约77 ppm的提高到145 ppm的10.1 GPA;（三）记录自由感应衰变为11.74磁场T（蓝色），17.6 T（红色）和两个（绿色）之间的差;（D）得到的自旋回波，在升高的压力下为不同的脉冲间隔时间。从迈斯纳等 23重印图1 <a href="https://www.jove.com/files/ftp_upload/52243/52243fig4highres.jpg" target="_blank">点击此处查看本图的放大版本。</a> 最重要的结果是从自由电子行为的奈特位移（1640 ppm的在环境压力下）的一个意想不到的偏差随着压力的升高。作为后续的带结构的计算结果显示这是由于费米表面的，这是迄今未知的利弗席兹过渡。另外一个unusUAL增加的字段无关的线宽在高压下被发现，不能尚未解释的。它可以由一个结构禁止四极相互作用引起的，或者它可以由于接近客霍夫奇异信号发生间接间核磁偶极子耦合的。可替换的压力梯度可能是这一发现背后，但是由于不同的传输介质得到了相似的结果，并与线宽为场独立，从立方结构仅偏差可以解释的结果。 这个例子说明，人们甚至可以了解著名的系统，随后可以定量测试，导致了国家的最先进的计算的校准信息的重要细节。例如，由于仅s状电子支配移位，我们甚至了解他们如何参与在费米表面的变化。 第二组实验中涉及的T 17 O核磁共振他的高温超导体的YBa 2铜4 O 8。这些实验是背后的高灵敏度压腔核磁共振的发展动力。随温度的NMR位移基本上已知的这个和其他超导体，甚至对于不同的掺杂水平。然而，由于这些系统还没有完全理解，一个是感兴趣的具有另一种合适的参数在手，人们可以在调查如何影响的核磁共振信号而变化。因为它是已知的，在这些系统中的17 O NMR由电子自旋（和无轨道影响）支配，它更倾向于对压力依赖性的研究。在这里，砧细胞用1毫米（2〜3 GPa）的0.8毫米（4.2〜6.3 GPa）的底尖碳硅石砧块被使用。的微线圈的尺寸类似于那些用于上述的金属铝的实验。当样品富含17 O，这样的实验在粉末样品仍然相当CHALL欢乐游戏。对进行测量时的11.75Ť磁场在温度从85 K到室温。核磁共振信号记录通过积累哈恩呼应28。通过改变射频脉冲电源，该π/ 2和π-脉冲的持续时间被发现是1.7微秒3.4微秒。的脉冲间隔是通常为30微秒。在RT下，Q因子为约12。乙1 -field为25 mT的在1瓦的平均RF功率脉冲，在好根据该预测值（43 mT）表示。通常的采集时间大约14小时的一个频谱。这个相当长的测量时间是由于相对低的拉莫尔频率和共振17 O核的粉末样品中的低数目。同样，这些第一实验证明，提供非常令人振奋的结果。这种材料（2的YBa铜4 O 8）获得了"果蝇"进行广泛的核磁共振实验中，早期。它是一种化学计量的材料，但显示的赝能隙特性，是这样的特性对于这个类的材料，但它不被理解。通过施加压力，温度换档的依赖性显著变化。赝特征逐渐消失随着压力的增加，类似，如果一个增加了对其它系统的掺杂水平会发生什么。此外，相当意外的，人们发现，这种情况下由两个移位部件的变化:其中一个稍微降低（它具有的温度在环境压力信号的相关性），行为类似，所述第二部件的金属是几乎不可见，在环境压力，但是被大大放大的压力和支配的移位以6.4 GPA的最高压力。 <img alt="图5" src="/files/ftp_upload/52243/52243fig5highres.jpg" /> 图5 17 O核磁共振上的YBa 2铜4 </stroNG&gt; O 8到6.4的GPA上图:观察17O核磁共振谱在6.3 GPA在110 K的观察线宽约为1500ppm的。下:录氧核磁共振谱。四个不同的17 O信号可以被识别（从平面，顶点和连锁氧而产生），即使是在温度105和110 K。转载图2与许可迈斯纳等人之间的更高的压力。24 <a href="https://www.jove.com/files/ftp_upload/52243/52243fig5highres.jpg" target="_blank">，请点击这里查看大图这个数字。</a> 有了这样惊人的结果，作者决定从事更深入的设计自制的高灵敏度压腔装置。 二）69,71嘎核磁共振液态镓的1.8 GPA 或明镜量化引入的碳硅石砧细胞中更详细的性能，液态镓被选择作为试验样品。用5N的纯度水平获得液态镓样品。微线圈的加载是通过液化一小块镓，随后填充入微线圈来实现的。为了获得这份报告中显示的数据，没有同位素增强样品进行使用; 69 Ga和71镓同位素的天然丰度被发现是足够的。 存在在升高的压力达2 GPA镓的液体状态。因此，非常敏感的高分辨率测量，可以进行这样的系统上。 图6示出了一些典型的69,71 Ga的核磁共振谱在室温，并为1.8GPa的压力。对进行测量时的11.74 1T的磁场用的砧座单元配备有两个800微米的底尖刻6H-SiC的伯勒尔型砧座，和一个4匝微线圈为200μm内直径由18微米直径的铜线。 Q因子为约18在120.5 MHz和150.3兆赫。该π/ 2脉冲的长度进行了调查在约150毫瓦的平均RF脉冲功率，并分别确定为3微秒和2μs的时间分别为69 Ga和71镓，。对应的磁场振幅被发现是28 MT和25 mT的与所述估计非常吻合。实验中，信号与噪声的比率被发现是信噪比（69 Ga）的= 0.8和SNR（71 Ga）的= 0.5在1 MHz的噪声带宽。以下ref的计算。如图19所示，预期的SNR计算为1和1.2的69 Ga和71镓，分别。据估计，仅4.6∙10 16和3∙10 16共振核的69 Ga和71嘎促成的NMR信号（微线圈的填充率为约50％）。 图6:69 Ga和液态镓的71尕核磁共振在1.8 GPA两个核磁共振积极镓核记录NMR谱。（蓝:69嘎，红色:71 Ga）的1.8 GPA在室温（主框架）。用的信号的频率与含水镓（NO 3）溶液的比较所得到的共振位移。左边边界:从垂头实验原子核均在150毫瓦平均脉冲功率得到的结果。右小图:从π获得的数据- π/ 2反转恢复实验<a href="https://www.jove.com/files/ftp_upload/52243/52243fig6highres.jpg" target="_blank">，请点击这里查看该图的放大版本。</a> 图6中的左端插入图示出了章动试验具有不同脉冲长度的典型结果。<html> 图6的右边小图显示了在一个π-π/ 2的反转恢复实验用于提高脉冲间隔时间所获得的观测信号强度的依赖性。使用单一指数法，自旋-晶格松弛率R 1被确定为，R 1 69 = 1740 -1和R 1 71 = 2020 -1。所有的光谱记录的11.74吨的磁场，并且是500次扫描的积累。这导致只有3秒为令人满意的光谱的总的数据采集时间（脉冲重复时间（RT）被选择为足够的关系:RT≥5 / R 1）。该数据的详细分析将在其他地方给出。 <img alt="图S1" fo:content-width="3in" src="/files/ftp_upload/52243/52243supfig1highres.jpg" width="300" /> 补充图1的蓝图LAC-TM2活塞。/www.jove.com/files/ftp_upload/52243/52243supfig1highres.jpg"目标="_ blank将"&gt;请点击这里查看该图的放大版本。 <img alt="图S2" fo:content-width="3in" src="/files/ftp_upload/52243/52243supfig2highres.jpg" width="300" /> 补充图2。蓝图的LAC-TM2壳。 <a href="https://www.jove.com/files/ftp_upload/52243/52243supfig2highres.jpg" target="_blank">请点击这里查看该图的放大版本。</a> <img alt="图中三" fo:content-width="3in" src="/files/ftp_upload/52243/52243supfig3highres.jpg" width="300" /> 补充图3蓝图的LAC-TM2的XY。 <a href="https://www.jove.com/files/ftp_upload/52243/52243supfig3highres.jpg" target="_blank">请点击这里查看该图的放大版本。</a>

Watch this Scientific Journal Video about High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extr

High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

Nuclear magnetic resonance is one of the most important spectroscopic tools. Here, the development of a new approach under high pressure, currently up to 10.1 GPa, is presented. This opens a new window into condensed matter physics and chemistry, where high-pressure research is of great importance.

高灵敏度核磁共振的千兆帕斯卡压力:一种新的工具，用于极端条件下探测电子和化工凝聚态的性质

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their ...

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Nanyang Technological University

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Unit 1

Principles of Nuclear Magnetic Resonance

SCIENTISTS IN ACTION

11.5K 次观看.  University of Leipzig. Nuclear magnetic resonance is one of the most important spectroscopic tools. Here, the development of a new approach under high pressure, currently up to 10.1 GPa, is presented. This opens a new window into condensed matter physics and chemistry, where high-pressure research is of great importance.

视频: High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

Hyperpolarized Xenon for NMR and MRI Applications

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature 1. Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration 2.
Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization 7 and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method.
The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials 8,9. Moreover, the Xe NMR signal is extremely sensitive to its molecular environment 6. This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas 10,11. Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode.

The production of hyperpolarized xenon by means of spin exchange optical pumping (SEOP) is described. This method yields a ~10000-fold enhancement of the nuclear spin polarization of Xe-129 and has applications in nuclear magnetic resonance spectroscopy and imaging. Examples of gas phase and solution state experiments are given.

超极化氙NMR和MRI的应用

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 ...

科研

工程学

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

在极端的压力和温度的合成和Microdiffraction

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Simulation of the Planetary Interior Differentiation Processes in the Laboratory

A planetary interior is under high-pressure and high-temperature conditions and it has a layered structure. There are two important processes that led to that layered structure, (1) percolation of liquid metal in a solid silicate matrix by planet differentiation, and (2) inner core crystallization by subsequent planet cooling. We conduct high-pressure and high-temperature experiments to simulate both processes in the laboratory. Formation of percolative planetary core depends on the efficiency of melt percolation, which is controlled by the dihedral (wetting) angle. The percolation simulation includes heating the sample at high pressure to a target temperature at which iron-sulfur alloy is molten while the silicate remains solid, and then determining the true dihedral angle to evaluate the style of liquid migration in a crystalline matrix by 3D visualization. The 3D volume rendering is achieved by slicing the recovered sample with a focused ion beam (FIB) and taking SEM image of each slice with a FIB/SEM crossbeam instrument. The second set of experiments is designed to understand the inner core crystallization and element distribution between the liquid outer core and solid inner core by determining the melting temperature and element partitioning at high pressure. The melting experiments are conducted in the multi-anvil apparatus up to 27 GPa and extended to higher pressure in the diamond-anvil cell with laser-heating. We have developed techniques to recover small heated samples by precision FIB milling and obtain high-resolution images of the laser-heated spot that show melting texture at high pressure. By analyzing the chemical compositions of the coexisting liquid and solid phases, we precisely determine the liquidus curve, providing necessary data to understand the inner core crystallization process.

The high-pressure and high-temperature experiments described here mimic planet interior differentiation processes. The processes are visualized and better understood by high-resolution 3D imaging and quantitative chemical analysis.

模拟行星内部分化过程中的实验室

A planetary interior is under high-pressure and high-temperature conditions and it has a layered structure. There are two important processes that led to ...

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR

The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of metabolic transformations. Hyperpolarization via dissolution DNP circumvents part of the sensitivity issues thanks to the large out-of-equilibrium nuclear magnetization stemming from the electron-to-nucleus spin polarization transfer. The high NMR signal obtained can be used to monitor chemical reactions in real time. The downside of hyperpolarized NMR resides in the limited time window available for signal acquisition, which is usually on the order of the nuclear spin longitudinal relaxation time constant, T1, or, in favorable cases, on the order of the relaxation time constant associated with the singlet-state of coupled nuclei, TLLS. Cellular uptake of endogenous molecules and metabolic rates can provide essential information on tumor development and drug response. Numerous previous hyperpolarized NMR studies have demonstrated the relevancy of pyruvate as a metabolic substrate for monitoring enzymatic activity in vivo. This work provides a detailed description of the experimental setup and methods required for the study of enzymatic reactions, in particular the pyruvate-to-lactate conversion rate in presence of lactate dehydrogenase (LDH), by hyperpolarized NMR.

The sensitivity enhancement provided by dissolution dynamic nuclear polarization (DNP) enables following metabolic processes in real time by NMR and MRI. The characteristics and performances of a dedicated dissolution DNP setup designed for study enzymatic reactions are discussed.

溶出动态核极化仪器用NMR实时酶反应速率测量

The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of ...

化学

High-pressure, High-temperature Deformation Experiment Using the New Generation Griggs-type Apparatus

In order to address geological processes at great depths, rock deformation should ideally be tested at high pressure (&#62; 0.5 GPa) and high temperature (&#62; 300 &#176;C). However, because of the low stress resolution of current solid-pressure-medium apparatuses, high-resolution measurements are today restricted to low-pressure deformation experiments in the gas-pressure-medium apparatus. A new generation of solid-medium piston-cylinder (&#34;Griggs-type&#34;) apparatus is here described. Able to perform high-pressure deformation experiments up to 5 GPa and designed to adapt an internal load cell, such a new apparatus offers the potential to establish a technological basis for high-pressure rheology. This paper provides video-based detailed documentation of the procedure (using the &#34;conventional&#34; solid-salt assembly) to perform high-pressure, high-temperature experiments with the newly designed Griggs-type apparatus. A representative result of a Carrara marble sample deformed at 700 &#176;C, 1.5 GPa and 10-5 s-1 with the new press is also given. The related stress-time curve illustrates all steps of a Griggs-type experiment, from increasing pressure and temperature to sample quenching when deformation is stopped. Together with future developments, the critical steps and limitations of the Griggs apparatus are then discussed.

Rock deformation needs to be quantified at high pressure. A description of the procedure to perform deformation experiments in a newly designed solid-medium Griggs-type apparatus is here given. This provides technological basis for future rheological studies at pressures up to 5 GPa.

新一代格雷型装置高压高温变形试验

In order to address geological processes at great depths, rock deformation should ideally be tested at high pressure (&#62; 0.5 GPa) and high temperature ...

环境科学

High Pressure Single Crystal Diffraction at PX^2

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the GSECARS 13-BM-C beamline at the Advanced Photon Source. The DAC program at 13-BM-C is part of the Partnership for Extreme Xtallography (PX^2) project. BX-90 type DACs with conical-type diamond anvils and backing plates are recommended for these experiments. The sample chamber should be loaded with noble gas to maintain a hydrostatic pressure environment. The sample is aligned to the rotation center of the diffraction goniometer. The MARCCD area detector is calibrated with a powder diffraction pattern from LaB6. The sample diffraction peaks are analyzed with the ATREX software program, and are then indexed with the RSV software program. RSV is used to refine the UB matrix of the single crystal, and with this information and the peak prediction function, more diffraction peaks can be located. Representative single crystal diffraction data from an omphacite (Ca0.51Na0.48)(Mg0.44Al0.44Fe2+0.14Fe3+0.02)Si2O6 sample were collected. Analysis of the data gave a monoclinic lattice with P2/n space group at 0.35 GPa, and the lattice parameters were found to be: a = 9.496 &#177;0.006 &#197;, b = 8.761 &#177;0.004 &#197;, c = 5.248 &#177;0.001 &#197;, &#946; = 105.06 &#177;0.03&#186;, &#945; = &#947; = 90&#186;.

In this report, we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell at the GSECARS 13-BM-C beamline at the Advanced Photon Source. ATREX and RSV programs are used to analyze the data.

高压单晶衍射PX ^ 2

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the ...

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic glasses (MGs). Despite their amorphous nature, the identification of hyperfine interactions unveils faint structural modifications. For this purpose, we have employed two techniques that utilize nuclear resonance among nuclear levels of a stable 57Fe isotope, namely M&#246;ssbauer spectrometry and nuclear forward scattering (NFS) of synchrotron radiation. The effects of heat treatment upon (Fe2.85Co1)77Mo8Cu1B14 MG are discussed using the results of ex situ and in situ experiments, respectively. As both methods are sensitive to hyperfine interactions, information on structural arrangement as well as on magnetic microstructure is readily available. M&#246;ssbauer spectrometry performed ex situ describes how the structural arrangement and magnetic microstructure appears at room temperature after the annealing under certain conditions (temperature, time), and thus this technique inspects steady states. On the other hand, NFS data are recorded in situ during dynamically changing temperature and NFS examines transient states. The use of both techniques provides complementary information. In general, they can be applied to any suitable system in which it is important to know its steady state but also transient states.

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Here, we present a protocol to describe ex situ and in situ investigations of structural transformations in metallic glasses. We employed nuclear-based analytical methods which inspect hyperfine interactions. We demonstrate the applicability of M&#246;ssbauer spectrometry and nuclear forward scattering of synchrotron radiation during temperature-driven experiments.

结构转换的原位和原位研究方法: 金属玻璃结晶的实例

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic ...

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States

High-pressure is a well-known perturbation method that can be used to destabilize globular proteins and dissociate protein complexes in a reversible manner. Hydrostatic pressure drives thermodynamical equilibria toward the state(s) with the lower molar volume. Increasing pressure offers, therefore, the opportunities to finely tune the stability of globular proteins and the oligomerization equilibria of protein complexes. High-pressure NMR experiments allow a detailed characterization of the factors governing the stability of globular proteins, their folding mechanisms, and oligomerization mechanisms by combining the fine stability tuning ability of pressure perturbation and the site resolution offered by solution NMR spectroscopy. Here we present a protocol to probe the local folding stability of a protein via a set of 2D 1H-15N experiments recorded from 1 bar to 2.5 kbar. The steps required for the acquisition and analysis of such experiments are illustrated with data acquired on the RRM2 domain of hnRNPA1.

We provide a detailed description of the steps required to assemble a high-pressure cell, set up and record high-pressure NMR experiments, and finally analyze both peak intensity and chemical shift changes under pressure. These experiments can provide valuable insights into the folding pathways and structural stability of proteins.

检测蛋白质低洼构象状态的高压NMR实验

High-pressure is a well-known perturbation method that can be used to destabilize globular proteins and dissociate protein complexes in a reversible ...

生物化学

An Externally-Heated Diamond Anvil Cell for Synthesis and Single-Crystal Elasticity Determination of Ice-VII at High Pressure-Temperature Conditions

The externally-heated diamond anvil cell (EHDAC) can be used to generate simultaneously high-pressure and high-temperature conditions found in Earth&#8217;s and planetary interiors. Here we describe the design and fabrication of the EHDAC assemblies and accessories, including ring resistive heaters, thermal and electrical insulating layers, thermocouple placement, as well as the experimental protocol for preparing the EHDAC using these parts. The EHDAC can be routinely used to generate megabar pressures and up to 900 K temperatures in open air, and potentially higher temperatures up to ~1200 K with a protective atmosphere (i.e., Ar mixed with 1% H2). Compared with a laser-heating method for reaching temperatures typically &#62;1100 K, external heating can be easily implemented and provide a more stable temperature at &#8804;900 K and less temperature gradients to the sample. We showcased the application of the EHDAC for synthesis of single crystal ice-VII and studied its single-crystal elastic properties using synchrotron-based X-ray diffraction and Brillouin scattering at simultaneously high-pressure high-temperature conditions.

This work focuses on the standard protocol for preparing the externally-heated diamond anvil cell (EHDAC) for generating high-pressure and high-temperature (HPHT) conditions. The EHDAC is employed to investigate materials in Earth and planetary interiors under extreme conditions, which can be also used in solid state physics and chemistry studies.

在高压-温度条件下用于冰-VII合成和单晶弹性的外热金刚石铁锤细胞

The externally-heated diamond anvil cell (EHDAC) can be used to generate simultaneously high-pressure and high-temperature conditions found in ...

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Nuclear magnetic resonance (NMR) spectroscopy represents an important technique to understand the structure and bonding environments of molecules. There exists a drive to characterize materials under conditions relevant to the chemical process of interest. To address this, in situ high-temperature, high-pressure MAS NMR methods have been developed to enable the observation of chemical interactions over a range of pressures (vacuum to several hundred bar) and temperatures (well below 0 &#176;C to 250 &#176;C). Further, the chemical identity of the samples can be comprised of solids, liquids, and gases or mixtures of the three. The method incorporates all-zirconia NMR rotors (sample holder for MAS NMR) which can be sealed using a threaded cap to compress an O-ring. This rotor exhibits great chemical resistance, temperature compatibility, low NMR background, and can withstand high pressures. These combined factors enable it to be utilized in a wide range of system combinations, which in turn permit its use in diverse fields as carbon sequestration, catalysis, material science, geochemistry, and biology. The flexibility of this technique makes it an attractive option for scientists from numerous disciplines.

The molecular structures and dynamics of solids, liquids, gases, and mixtures are of critical interest to diverse scientific fields. High-temperature, high-pressure in situ MAS NMR enables detection of the chemical environment of constituents in mixed phase systems under tightly controlled chemical environments.

高温高压原位魔角旋转核磁共振光谱

Nuclear magnetic resonance (NMR) spectroscopy represents an important technique to understand the structure and bonding environments of molecules. There ...