Name: high-temperature and high-pressure in situ magic angle spinning nuclear magnetic resonance spectroscopy
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The review of catalyst applications was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences, and Geosciences Catalysis Program under contract DE-AC05-RL01830 and FWP-47319. The review of biomedical applications was supported by the National Institute of Health, National Institute of Environmental Health Sciences under grant R21ES029778. Experiments were conducted at EMSL (grid.436923.9), a DOE Office of Science User Facility sponsored by the Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is a multi-program national laboratory operated by Battelle for the U.S. Department of Energy under contract DE-AC05-RL01830 and FWP-47319.

The protocol is divided into four sections which specify 1) the preparation of any solid materials being used in the system or activation or clearing of undesired adsorbed species, 2) addition of the solid and liquid materials to the NMR rotor, 3) addition of gases to the rotor, and 4) conducting the NMR experiments in the spectrometer. The procedure is representative of a typical sequence but may be modified to fit the specific needs of the experiment.
1. Pretreating solid samples
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C., 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+in+situ+129Xe+NMR+spectroscopy+and+computer+simulations+of+breathing+transitions+in+the+metal-organic+framework+Ni2(2,6-ndc)2(dabco)+(DUT-8(Ni)).">High-pressure in situ 129Xe NMR spectroscopy and computer simulations of breathing transitions in the metal-organic framework Ni2(2,6-ndc)2(dabco) (DUT-8(Ni)).</a> Journal of the American Chemical Society. 133 (22), 8681-8690 (2011).</li><li>Turcu, R. V. F., 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=Rotor+design+for+high+pressure+magic+angle+spinning+nuclear+magnetic+resonance.">Rotor design for high pressure magic angle spinning nuclear magnetic resonance.</a> Journal of Magnetic Resonance. 226, 64-69 (2013).</li><li>Jaegers, N. R., Hu, M. Y., Hoyt, D. W., Wang, Y., Hu, J. 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R., Linehan, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+supercritical+fluids+as+solvents+for+NMR+spectroscopy.">The use of supercritical fluids as solvents for NMR spectroscopy.</a> Progress in Nuclear Magnetic Resonance Spectroscopy. 47 (1), 95-109 (2005).</li><li>Deuchande, T., Breton, O., Haedelt, J., Hughes, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+performance+of+a+high+pressure+insert+for+use+in+a+standard+magic+angle+spinning+NMR+probe.">Design and performance of a high pressure insert for use in a standard magic angle spinning NMR probe.</a> Journal of Magnetic Resonance. 183 (2), 178-182 (2006).</li><li>Hoyt, D. W., 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+magic+angle+spinning+nuclear+magnetic+resonance.">High-pressure magic angle spinning nuclear magnetic resonance.</a> Journal of Magnetic Resonance. 212 (2), 378-385 (2011).</li><li>Vjunov, A., 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=Following+Solid-Acid-Catalyzed+Reactions+by+MAS+NMR+Spectroscopy+in+Liquid+Phase-Zeolite-Catalyzed+Conversion+of+Cyclohexanol+in+Water.">Following Solid-Acid-Catalyzed Reactions by MAS NMR Spectroscopy in Liquid Phase-Zeolite-Catalyzed Conversion of Cyclohexanol in Water.</a> Angewandte Chemie International Edition. 53 (2), 479-482 (2014).</li><li>Chamas, A., 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+temperature/pressure+MAS-NMR+for+the+study+of+dynamic+processes+in+mixed+phase+systems.">High temperature/pressure MAS-NMR for the study of dynamic processes in mixed phase systems.</a> Magnetic Resonance Imaging. 56, 37-44 (2019).</li><li>Hu, J. Z., 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=Sealed+rotors+for+in+situ+high+temperature+high+pressure+MAS+NMR.">Sealed rotors for in situ high temperature high pressure MAS NMR.</a> ChemComm. 51 (70), 13458-13461 (2015).</li><li>Hu, J. Z., Hu, M. Y., Townsend, M. R., Lercher, J. A., Peden, C. H. <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,+high-temperature+magic+angle+spinning+nuclear+magnetic+resonance+devices+and+processes+for+making+and+using+same.">High-pressure, high-temperature magic angle spinning nuclear magnetic resonance devices and processes for making and using same.</a> US patent. , (2015).</li><li>Jaegers, N. R., Mueller, K. T., Wang, Y., Hu, J. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variable+Temperature+and+Pressure+Operando+MAS+NMR+for+Catalysis+Science+and+Related+Materials.">Variable Temperature and Pressure Operando MAS NMR for Catalysis Science and Related Materials.</a> Accounts of Chemical Research. 53 (3), 611-619 (2020).</li><li>Dagle, V., 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=Single-step+Conversion+of+Ethanol+to+n-butenes+over+Ag-ZrO2/SiO2+catalysts.">Single-step Conversion of Ethanol to n-butenes over Ag-ZrO2/SiO2 catalysts.</a> ACS Catalysis. 10 (18), 10602-10613 (2020).</li><li>Jaegers, N. R., Wang, Y., Hu, J. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+perturbation+of+NMR+properties+in+small+polar+and+non-polar+molecules.">Thermal perturbation of NMR properties in small polar and non-polar molecules.</a> Scientific Reports UK. 10 (1), 6097 (2020).</li><li>Jaegers, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Applications of In situ Magnetic Resonance Spectroscopy for Structural Analysis of Oxide-supported Catalysts. , (2019).</li><li>Mehta, H. S., 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=A+novel+high-temperature+MAS+probe+with+optimized+temperature+gradient+across+sample+rotor+for+in-situ+monitoring+of+high-temperature+high-pressure+chemical+reactions.">A novel high-temperature MAS probe with optimized temperature gradient across sample rotor for in-situ monitoring of high-temperature high-pressure chemical reactions.</a> Solid State Nuclear Magnetic Resonance. 102, 31-35 (2019).</li><li>Hu, J. Z., 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=A+large+sample+volume+magic+angle+spinning+nuclear+magnetic+resonance+probe+for+in+situ+investigations+with+constant+flow+of+reactants.">A large sample volume magic angle spinning nuclear magnetic resonance probe for in situ investigations with constant flow of reactants.</a> Physical Chemistry Chemical Physics. 14 (7), 2137-2143 (2012).</li><li>Jiang, 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=In+situ+MAS+NMR-UV/Vis+investigation+of+H-SAPO-34+catalysts+partially+coked+in+the+methanol-to-olefin+conversion+under+continuous-flow+conditions+and+of+their+regeneration.">In situ MAS NMR-UV/Vis investigation of H-SAPO-34 catalysts partially coked in the methanol-to-olefin conversion under continuous-flow conditions and of their regeneration.</a> Microporous and Mesoporous Materials. 105 (1-2), 132-139 (2007).</li><li>Xu, S., Zhang, W., Liu, X., Han, X., Bao, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+In+situ+Continuous-Flow+MAS+NMR+for+Reaction+Kinetics+in+the+Nanocages.">Enhanced In situ Continuous-Flow MAS NMR for Reaction Kinetics in the Nanocages.</a> Journal of the American Chemical Society. 131 (38), 13722-13727 (2009).</li><li>Graham, T. R., 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=In+situ+Al-27+NMR+Spectroscopy+of+Aluminate+in+Sodium+Hydroxide+Solutions+above+and+below+Saturation+with+Respect+to+Gibbsite.">In situ Al-27 NMR Spectroscopy of Aluminate in Sodium Hydroxide Solutions above and below Saturation with Respect to Gibbsite.</a> Inorganic Chemistry. 57 (19), 11864-11873 (2018).</li><li>Zhang, X., 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=Boehmite+and+Gibbsite+Nanoplates+for+the+Synthesis+of+Advanced+Alumina+Products.">Boehmite and Gibbsite Nanoplates for the Synthesis of Advanced Alumina Products.</a> ACS Applied Nano Materials. 1 (12), 7115-7128 (2018).</li><li>Zhang, X., 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=Transformation+of+Gibbsite+to+Boehmite+in+Caustic+Aqueous+Solution+at+Hydrothermal+Conditions.">Transformation of Gibbsite to Boehmite in Caustic Aqueous Solution at Hydrothermal Conditions.</a> Crystal Growth &amp; Design. 19 (10), 5557-5567 (2019).</li><li>Hu, J. 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The method of conducting MAS NMR spectroscopic measurements outlined herein represents the state of the art for conducting high-temperature, high-pressure MAS NMR. Such methods enable the observation of interactions occurring in vacuum atmospheres up to several hundred bar and from low temperatures (well below 0 &#176;C to 250 &#176;C) in a reliable, reproducible fashion. The ability to probe systems containing mixtures of solids, liquids, and gases under flexible chemical environments enables a wide range of experiments...

Spectroscopic analysis of samples is an analytical tool used to gain valuable information about materials of interest such as their chemical state, structure, or reactivity. In a simplistic view, nuclear magnetic resonance (NMR) is one such technique that utilizes a strong magnetic field to manipulate the spin state of atomic nuclei to better understand the chemical environment of the species of interest. The nuclear spin state refers to the relative direction of the magnetic moment induced by the motion of the spinning nucleus, a positively charged particle. In the absence of a magnetic field, the nuclear spins are randomly oriented but in the presence of a magnetic field, nuclear spins preferentially align with the external field of the magnet in a low energy spin state. This splitting of spin states to discrete energy values is known as the Zeeman effect. The difference between these energy levels (&#916;E) is modeled by Equation 1: 
<img alt="Equation 1" src="/files/ftp_upload/61794/61794equ01.jpg" /> 
where h is Plank&#8217;s constant, B0 is the strength of the external magnetic field and &#947; is the gyromagnetic ratio of the nucleus. The chemical environment of these spins also applies slight perturbations to these energy levels. Radio waves of corresponding frequencies can be used to excite the nuclei, which generates a transverse magnetization due to spins gaining phase coherence as longitudinal magnetization (based on the population of spins in parallel and anti-parallel states) is decreased. As the nuclei continue precessing about the axis of the magnetic field, the rotating magnetic movement creates a magnetic field that is also rotating and generating an electric field. This field modulates the electrons in the NMR detection coil, generating the NMR signal. Slight differences in the chemical environment of the nuclei in the sample affect the frequencies detected in the coil.
NMR analysis of solid samples introduces complexities not found in fluids. In fluids, the molecules tumble at fast rates, averaging the chemical environment spatially around the nuclei. In solid samples, no such averaging effect occurs, introducing an orientation-dependent chemical environment and broad spectral lines in the NMR signal. To mitigate these challenges, a technique known as magic angle spinning (MAS) is employed1,2. In MAS NMR, the samples are quickly rotated (several kilohertz) at an angle of 54.7356&#176; with respect to the external magnetic field using an external spinning mechanism to address the orientation-dependent (anisotropic) interactions of NMR. This substantially narrows the NMR features and enhances the spectral resolution by averaging the orientation-dependent terms of the chemical shift anisotropy, dipolar interactions, and quadrupolar interactions. Two notable exceptions do hinder the line narrowing abilities of MAS NMR. The first is strong homonuclear coupling sometimes present in 1H NMR that requires high spinning speeds (~70 kHz) to remove. However, the significantly elevated temperatures of the high temperature applications will greatly suppress the 1H homonuclear interaction by imparting enhanced thermal motion such that a much reduced sample spinning rate can be utilized for significantly enhanced spectral resolution. Furthermore, with the technology continuously evolving, rotors with smaller diameters can now be fabricated to achieve spinning rates far exceeding 5 kHz, which helps to further suppress the 1H homonuclear dipolar interactions. The second exception is residual second-order quadrupolar interactions for nuclei with spin that exceeds one-half since only the first order term is eliminated at the magic angle, leaving more complex lineshapes that can only be improved by stronger external magnetic fields. It should be emphasized that 2D MQMAS techniques can be readily incorporated into the current technology so that a true isotropic chemical shift spectrum can be obtained in a similar way as to the standard MQMAS experiments3.
MAS NMR has enabled detailed characterization of solid materials, strengthening the quality of observations. However, the necessity of spinning the samples in NMR rotors (the sample holder) at high rates also imposes challenges in conducting experiments at elevated temperatures and pressures which may be more relevant to the conditions of interest. It may, at times, be desirable to examine materials under conditions that are relatively harsh for NMR rotors. A number of efforts have successfully adapted liquid-state NMR technologies to conduct high-temperature, high-pressure NMR4,5,6,7; however, commercial rotor caps used for solid-state MAS NMR may be expelled from the rotor at high pressures, causing significant damage to the equipment. Such effects may be compounded by examining a decomposition reaction that greatly increases the pressure in the sample holder. As such, new designs are required to effectively and safely conduct in situ NMR experiments. For example, the rotor must adhere to several qualities for effective use in MAS NMR, namely non-magnetic, lightweight, durable, temperature resistant, low NMR background material, sealable, high-strength, and chemical resistant. The pressures the rotor must withstand are quite large. Not only must the rotor withstand the pressure of the sample contained within (e.g., high-pressure gas), the rotation of the device imparts centrifugal force which has its own contribution to the total system pressure8, PT, by equation 2: 
<img alt="Equation 2" src="/files/ftp_upload/61794/61794equ02.jpg" /> 
RI and RO are the inner and outer rotor radii, respectively, &#969; is the rotational frequency in radians per second, and Ps is the sample pressure.
A number of strategies have been developed to address these concerns9. Early examples resembled flame-sealed tubes10,11,12 or polymer inserts13,14, which were insufficient for extended, fine-controlled operation at elevated temperatures and pressures. Iterations to rotor designs have suffered from limitations in the maximum operating temperature imparted by the use of epoxy or sample volume reductions from ceramic inserts8,15,16. A recent technology reduces unit production costs by employing simple snap-in features in a commercial rotor sleeve, but offers relatively less control over the conditions with which it can operate17. The design employed herein is an all-zirconia, cavern-style rotor sleeve milled with a threaded top18. A cap is also threaded to allow for a secure seal. Reverse threading prevents sample rotation from loosening the zirconia cap and an O-ring constitutes the sealing surfaces. This rotor design is visible in Figure 1 and similar rotors and instructions to make them have been patented19. Such a strategy enables high mechanical strength, chemical resistance, and temperature tolerance.
These designs are suitable for temperatures and pressures of at least 250 &#176;C and 100 bar, limited in temperature by readily-available NMR probe technology. When combined with specialized sample preparation equipment, it represents a truly powerful technique that has been employed for far-reaching applications as carbon sequestration, catalysis, energy storage, and biomedicine20. Such equipment includes a way to pretreat the solid materials to remove unwanted surface species such as water. A furnace is often employed for this step. A dry box is typically used to load the solid samples into the NMR rotor. From there, the rotor is transferred into an exposure device which enables the rotor to be opened under a tightly controlled atmosphere to load a desired gas or mixture into the rotor. Such a device is depicted in Figure 2.

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			<td>1) Preparation of Solids Samples</td>
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			<td>Gas maniforld</td>
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			<td>Gas Mass Flow Controllers</td>
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			<td>Vacuum Pump</td>
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			<td>Tube Furnace</td>
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			<td>Temperature Controller</td>
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			<td>Thermocouple</td>
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			<td>Quartz Tube</td>
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			<td>Isolation Valves</td>
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			<td>Quartz Wool</td>
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			<td>2) Loading solid samples into the rotor</td>
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			<td>Dry glove box</td>
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			<td>High-temperature, high-pressure NMR rotor</td>
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			<td>Sample funnel</td>
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			<td>Sample packing rod</td>
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			<td>Rotor holder</td>
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			<td>Analytical Balance</td>
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			<td>Microsyringe</td>
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			<td>Rotor cap bit</td>
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			<td>3) Addition of gases to the rotor</td>
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			<td>NMR loading chamber</td>
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			<td>Rotor stage and appropriately sized inserts</td>
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			<td>Vacuum Pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gas maniforld</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gas Mass Flow Controllers</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum Pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Heating Tape</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature Controller</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocouple</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Allen wrench</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Threaded rod</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Wrenchs</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pressure Gauge</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>High-pressure syringe pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid syringe pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4) Conducting the NMR experiments</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MAS NMR probe</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NMR spectrometer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Computer to control the spectrometer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

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 output from the NMR spectrometer takes the form of a free induction decay (FID) which is the time-domain signal from the excited spins as they relax back to thermodynamic equilibrium. Such an FID resembles Figure 3. When Fourier transformed from the time domain to the frequency domain (frequency to PPM by Equation 3, whereby the difference absolute frequency and a reference is divided by the carrier frequency of the NMR spectrometer), it represents the NMR spectrum for which each peak in...

Watch this Scientific Journal Video about High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy at JoVE.com

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

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.

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

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Interpreting Nuclear Magnetic Resonance Spectra

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In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

대량 선택 이온 소프트 랜딩에 의해 준비 잘 정의 된 표면의 제자리 SIMS 및 IR 분광법

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using ...

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Sequencing of Plant Wall Heteroxylans Using Enzymic, Chemical (Methylation) and Physical (Mass Spectrometry, Nuclear Magnetic Resonance) Techniques

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This protocol describes the specific techniques used for the characterization of reducing end (RE) and internal region glycosyl sequence(s) of ...

In Situ Monitoring of Diffusion of Guest Molecules in Porous Media Using Electron Paramagnetic Resonance Imaging

In Situ Monitoring of Diffusion of Guest Molecules in Porous Media Using Electron Paramagnetic Resonance Imaging

전자 상자성 공명 영상을 이용하여 다공성 미디어에서 고객 분자의 확산의 제자리 모니터링에

A method is demonstrated to monitor macroscopic translational diffusion using electron paramagnetic resonance (EPR) imaging. A host-guest system with ...

High Pressure Single Crystal Diffraction at PX^2

고압 PX에서 단결정 회절 ^ 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 ...

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

준비 및<em&gt; 체외</em&gt; 자기 공명 영상에 대한 덴드리머 기반 대조 대리인의 특성

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

제자리에서 검색 및 핵 현미경 분석을 사용 하 여 금속 산화물 나노 입자의 단일 셀 정량화

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

효율적인 고온 화학을위한 비평 형 마이크로 웨이브 플라즈마

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose ...

Microfluidic Dry-spinning and Characterization of Regenerated Silk Fibroin Fibers

미세 드라이 회전 및 재생성된 실크 Fibroin 섬유의 특성

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables ...

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

추출 및 카 테 콜 아민 신경 전달 물질과 그들의 대사 산물의 고압 액체 크로마토그래피로 분석 하는 편리한 방법

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and ...

In Situ Lithiated Reference Electrode: Four Electrode Design for In-operando Impedance Spectroscopy

원래의 Lithiated 참조 전극: 4 개의 전극 디자인-operando 임피던스 분광학에 대 한

Extending operating voltage of Li-ion batteries results in higher energy output from these devices. High voltages, however, may trigger or accelerate ...