Nuclear Magnetic Resonance Observations Research Articles

Porosity and pore structure evolution during the weathering of black shale

Pore type and pore structure evolves systematically across continuous black shale weathering profile. However, the extend and process of pore structure change is still an enigma. In this study, we try to unveil the pore structure evolution during weathering process through studying Cambrian Hetang shales in southern China. Fourteen shale samples, from protolith zone (PZ), fractured and weathered shale zone (FWZ), and saprolite zone (SZ), were collected to elucidate how porosity and pore structure develop during black shale weathering under subtropical condition. Through low pressure argon (Ar) gas adsorption (LP-ArGA), high pressure mercury intrusion (HPMI), nuclear magnetic resonance(NMR) and field emission scanning electron microscope (FESEM) observation, the results reveal significant differences in physical properties and pore structures among the PZ, FWZ, and SZ samples. Specifically, compared to PZ, FWZ and SZ samples are characterized by higher clay mineral content, lower organic matter (OM), and the absence of carbonates and pyrite. Total porosity, determined through HPMI and NMR, exhibits a gradual increase from PZ (6.70 % and 6.41 %) to FWZ (20.47 % and 13.45 %) and SZ (23.22 % and 12.48 %). Ar adsorption isotherms indicate a change in pore type from predominantly ink-bottle and slit-shaped in the PZ to mainly slit-shaped in FWZ and SZ. Integrated analysis of LP-ArGA, HPMI, NMR and SEM observation suggests a substantial decrease in the contribution of micropores to total pore volume (PV) and a concurrent increase in larger pores (meso-macropores) with the increase of weathering intensity. This results in smoother surfaces of micro-transition pores but rougher surfaces of macropores. Changes in mineralogy composition during weathering play a crucial role in influencing pore structure of shales and further accelerating the release and migration of toxic elements in black shale. Our study provides the essential theoretical foundation for the remediation of soil and water environmental pollution caused by black shale weathering.

Highly Electrophilic Intermediates in the Bypass Mechanism of Glutathione Peroxidase: Synthesis, Reactivity, and Structures of Selenocysteine-Derived Cyclic Selenenyl Amides.

Selenocysteine (Sec)-derived cyclic selenenyl amides, formed by the intramolecular cyclization of Sec selenenic acids (Sec-SeOHs), have been postulated to function as protective forms in the bypass mechanism of glutathione peroxidase (GPx). However, their chemical properties have not been experimentally elucidated in proteins or small-molecule systems. Recently, we reported the first nuclear magnetic resonance observation of Sec-SeOHs and their cyclization to the corresponding cyclic selenenyl amides by using selenopeptide model systems incorporated in a molecular cradle. Herein, we elucidate the structures and reactivities of Sec-derived cyclic selenenyl amides. The crystal structures and reactions toward a cysteine thiol or a 1,3-diketone-type chemical probe indicated the highly electrophilic character of cyclic selenenyl amides. This suggests that they can serve not only as protective forms to suppress the inactivation of Sec-SeOHs in GPx but also as highly electrophilic intermediates in the reactions of selenoproteins.

Stereodirecting Effect of Esters at the 4-Position of Galacto- and Glucopyranosyl Donors: Effect of 4-C-Methylation on Side-Chain Conformation and Donor Reactivity, and Influence of Concentration and Stoichiometry on Distal Group Participation.

When generated in a mass spectrometer bridged bicyclic 1,3-dioxenium ions derived from 4-O-acylgalactopyranosyl, donors can be observed by infrared spectroscopy at cryogenic temperatures, but they are not seen in the solution phase in contrast to the fused bicyclic 1,3-dioxalenium ions of neighboring group participation. The inclusion of a 4-C-methyl group into a 4-O-benzoyl galactopyranosyl donor enables nuclear magnetic resonance observation of the bicyclic ion arising from participation by the distal ester, with the methyl group influence attributed to ester ground state conformation destabilization. We show that a 4-C-methyl group also influences the side-chain conformation, enforcing a gauche,trans conformation in gluco and galactopyranosides. Competition experiments reveal that the 4-C-methyl group has only a minor influence on the rate of reaction of 4-O-benzoyl or 4-O-benzyl-galacto and glucopyranosyl donors and, consequently, that participation by the distal ester does not result in kinetic acceleration (anchimeric assistance). We demonstrate that the stereoselectivity of the 4-O-benzoyl-4-C-methyl galactopyranosyl donor depends on reaction concentration and additive (diphenyl sulfoxide) stoichiometry and hence that participation by the distal ester is a borderline phenomenon in competition with standard glycosylation mechanisms. An analysis of a recent paper affirming participation by a remote pivalate ester is presented with alternative explanations for the observed phenomena.

The influence of water on the failure characteristics of sandstone under uniaxial compression conditions by acoustic emission and NMR observation

Revealing the failure characteristics and damage process of rocks soaked in water is particularly critical for preventing and controlling geological disasters. To this end, we employed nuclear magnetic resonance (NMR) and an ultrasonic system to capture the variation in the T2 spectrum, different pore waters and P-wave velocity during soaking (from 0 to 120 h). Furthermore, an acoustic emission (AE)-uniaxial compression test was carried out to analyse the AE characteristics (e.g., hits, absolute energy, and events), and strength of sandstone under different soaking times. The AF (the ratio of AE counts to duration)-RA (the ratio of the AE rise time to amplitude) is used to distinguish the tensile failure shear failure of sandstone during soaking. The results showed that the increase in soaking time decreased the bound water percentage and strength while increasing the P-wave velocity and capillary water percentage. An interesting phenomenon was that the failure mode was transformed due to soaking based on the evolution of the AE response. From the above results and classical water-weakening mechanisms, we suggest that the weakening process after loading can be divided into three stages. In the initially soaking, the reduction in fracture toughness and frictional more serious caused the increase in the occurrence of tensile failure. The quartz hydrolysis and chemical deterioration may aggravate the shear failure and intergranular fracture during long-term soaking. This study clarifies the transformation of weakening mechanisms during soaking and is of great significance for understanding the microscopic damage processes in rock failure.

Hydration of Transitional Shale and Evolution of Physical Properties Constrained by Concurrent NMR and Acoustic Observations

Hydration state is a key factor affecting the pore structure and mechanical properties of shale that directly impacts the migration and then production of geofluids. We quantify the impact of the hydration state on physical properties through spontaneous imbibition experiments constrained by concurrent nuclear magnetic resonance (NMR) and acoustic observations as diagnostics of response. The long-duration experiments (24 days) are on samples from the Permian Shanxi Formation of the Ordos Basin, complemented by measurements of composition and physical properties. These shales primarily comprise quartz and clay minerals with intraparticle pores present within the clay minerals. The NMR T2 spectra indicate that mesopores (2–50 nm) comprise ∼80% of the total pore space. The imbibition rate decreases by a factor of 3 from 0.08 g/h to a stable rate of 0.03 g/h from the 1st to the 24th hour. This is accompanied by a 10% decrease in the deformation modulus from 44 to 40.3 GPa over 24 days. The reduction in the modulus is consistent with observations of the shedding and spalling of hydrophilic quartz particles from the unconstrained surface and the generation of fractures. Reduction in the imbibition rate is consistent with the swelling followed by squeezing of clay minerals and the corresponding reduction in pore diameters in the confined core of the sample, together with the reduction in saturation gradients with the progress of imbibition. Understanding the mechanisms and effects of hydration on the pore structure and mechanical properties is important in understanding the shale hydration process and defining diagnostic (acoustic and NMR) signatures that may be used in reservoir surveillance.

Structural Changes in Liposomal Vesicles in Association with Sodium Taurodeoxycholate.

Liposomes composed of soy lecithin (SL) have been studied widely for drug delivery applications. The stability and elasticity of liposomal vesicles are improved by incorporating additives, including edge activators. In this study, we report the effect of sodium taurodeoxycholate (STDC, a bile salt) upon the microstructural characteristics of SL vesicles. Liposomes, prepared by the thin film hydration method, were characterized by dynamic light scattering (DLS), small-angle neutron scattering (SANS), electron microscopy, and rheological techniques. We noticed a reduction in the size of vesicles with the incremental addition of STDC. Initial changes in the size of spherical vesicles were ascribed to the edge-activating action of STDC (0.05 to 0.17µM). At higher concentrations (0.23 to 0.27µM), these vesicles transformed into cylindrical structures. Morphological transitions at higher STDC concentrations would have occurred due to its hydrophobic interaction with SL molecules in the bilayer. This was ascertained from nuclear magnetic resonance observations. Whereas shape transitions underscored the deformability of vesicles in the presence of STDC, the consistency of bilayer thickness ruled out any dissociative effect. It was interesting to notice that SL-STDC mixed structures could survive high thermal stress, electrolyte addition, and dilution.

Characterizing Nanoparticle Mass Distributions Using Charge-Independent Nanoresonator Mass Spectrometry

Due to their unique size-dependent properties, nanoparticles (NPs) have many industrial and biomedical applications. Although NPs are generally characterized based on the size or morphological analysis, the mass of whole particles can be of interest as it represents the total amount of material in the particle regardless of shape, density, or elemental composition. In addition, the shape of nonspherical NPs presents a conceptual challenge, making them difficult to characterize in terms of size or morphological characteristics. Here, we used a novel nano-electro-mechanical sensor mass spectrometry (NEMS-MS) technology to characterize the mass distributions of various NPs. For standard spherical gold NPs, mass distributions covered the range from ∼5 to 250 MDa (8 to ∼415 attograms). Applying the density of gold (19.3 g/cm3) and assuming perfect sphericity, these mass measurements were used to compute the equivalent diameters of the NPs. The sizes determined agreed well with the transmission electron microscopy (TEM) imaging data, with deviations of ∼1.4%. Subsequently, we analyzed the mass distribution of ∼50 nm synthetic silicon dioxide particles, having determined their size by electron microscopy (SEM and TEM). Their estimated density was in line with the literature values derived from differential mobility analyzer and aerosol particle mass analyzer data. Finally, we examined the intact gold nanotetrapods and obtained a mass distribution revealing their controlled polydispersity. The presence of polyethylene glycol coating was also quantified and corroborated nuclear magnetic resonance observations. Our results demonstrate the potential of NEMS-MS-based measurements as an effective means to characterize NPs, whatever their composition, shape or density.

Mechanistic Versatility at Ir(PSiP) Pincer Catalysts: Triflate Proton Shuttling from 2-Butyne to Diene and [3]Dendralene Motifs.

The five-coordinate hydrido complex [IrH(OTf)(PSiP)] (1) catalytically transforms 2-butyne into a mixture of its isomer 1,3-butadiene, and [3]dendralene and linear hexatriene dimerization products: (E)-4-methyl-3-methylene-1,4-hexadiene and (3Z)-3,4-dimethyl-1,3,5-hexatriene, respectively. Under the conditions of the catalytic reaction, benzene, and 363 K, the hexatriene further undergoes thermal electrocyclization into 2,3-dimethyl-1,3-cyclohexadiene. The reactions between 1 and the alkyne substrate allow isolation or nuclear magnetic resonance (NMR) observation of catalyst resting states and possible reaction intermediates, including complexes with the former PSiP pincer ligands disassembled into PSi and PC chelates, and species coordinating allyl or carbene fragments en route to products. The density functional theory (DFT) calculations guided by these experimental observations disclose competing mechanisms for C–H bond elaboration that move H atoms either classically, as hydrides, or as protons transported by the triflate. This latter role of triflate, previously recognized only for more basic anions such as carboxylates, is discussed to result from combining the unfavorable charge separation in the nonpolar solvent and the low electronic demand from the metal to the anion at coordination positions trans to silicon. Triflate deprotonation of methyl groups is key to release highly coordinating diene products from stable allyl intermediates, thus enabling catalytic cycling.

Development of Self-Administered Formulation to Improve the Bioavailability of Leuprorelin Acetate.

In recent years, the development of self-injectable formulations has attracted much attention, and the development of formulations to control pharmacokinetics, as well as drug release and migration in the skin, has become an active research area. In the present study, the development of a lipid-based depot formulation containing leuprorelin acetate (LA) as an easily metabolizable drug in the skin was prepared with a novel non-lamellar liquid-crystal-forming lipid of mono-O-(5,9,13-trimethyl-4-tetradecenyl) glycerol ester (MGE). Small-angle X-ray scattering, cryo-transmission electron microscopy, and nuclear magnetic resonance observations showed that the MGE-containing formulations had a face-centered cubic packed micellar structure. In addition, the bioavailability (BA) of LA after subcutaneous injection was significantly improved with the MGE-containing formulation compared with the administration of LA solution. Notably, higher Cmax and faster Tmax were obtained with the MGE-containing formulation, and the BA increased with increasing MGE content in the formulation, suggesting that LA migration into the systemic circulation and its stability might be enhanced by MGE. These results may support the development of self-administered formulations of peptide drugs as well as nucleic acids, which are easily metabolized in the skin.

Impact of Hydroxypropyl Methylcellulose Acetate Succinate Critical Aggregation Concentration on Celecoxib Supersaturation.

Polymers play an important role in amorphous solid dispersions (ASDs), enhancing stability in the solid state and maintaining supersaturation in aqueous solutions of intrinsically low-water-soluble drug candidates. Hydroxypropyl methylcellulose acetate succinate (HPMCAS) is widely used in ASDs due to its hydrophobic/hydrophilic balance and ionizability of the substituent functionalities. While colloid formation of HPMCAS in solution due to this hydrophobic/hydrophilic balance has been studied, the impact of the polymer conformation (random coil vs aggregated) on drug supersaturation of ASDs is not well understood. To our knowledge, this is the first report where the critical aggregation concentration for three grades of HPMCAS (HF/MF/LF) has been determined via fluorescence spectroscopy using the environment-sensitive probe pyrene. The specific impact of polymer conformation (random coil vs aggregate) on the model drug celecoxib (CLX) has been elucidated with fluorescence quenching and nuclear magnetic resonance (NMR) spectroscopy. A negative deviation of the Stern-Volmer plot indicated that aggregated HPMCAS effectively blocked the quencher's access to CLX. This is further supported by NMR observations, where NMR spectra indicate a larger change of chemical shift of the -NH group of CLX when HPMCAS is above its aggregated concentration, suggesting strong H-bonding interactions between aggregated HPMCAS and CLX. Finally, the supersaturation-precipitation study shows that all three grades of HPMCAS in the aggregated state significantly enhanced CLX supersaturation compared to the nonaggregated state, indicating that polymer aggregation plays a critical role in maintaining drug supersaturation.

Study on the water state, migration, and microstructure modification during the process of salt-reduced stewed duck.

High salt content is one of the major problems for stewed products. To help address this issue, the effect of salt reduction on water migration in stewed ducks was investigated through diverse approaches, including water activity (Aw) and water-holding capacity (WHC) assay, as well as low-field nuclear magnetic resonance (LF-NMR) and scanning electron microscopy (SEM) observation. Our results showed that Aw value remained stable, while centrifugal loss decreased, and cooking loss increased significantly (p<0.05). The analysis of NMR indicated that, during the marinating stage, the proportion of immobilized water increased from 86.86%-89.66% (sodium chloride group) and 90.51% (salt-reduced group), respectively. After 2 h, the free water content became 0, and then became stable until the end of marinating. In the stewing stage, at the beginning 20min, relaxation time of immobilized water decreased to about 35ms and the ratio of immobilized water significantly reduced (p<0.05) by 5.38% (sodium chloride group) and 5.95% (salt-reduced group), respectively. Free water peak was detected upon stewing of 10min, and 20min later, there was no significant difference in the proportion of free water (p>0.05). In general, no significance was observed in water behavior and microstructure of stewed duck meat between the salt reduction group and sodium chloride group. In addition, SEM analysis revealed that marinating could expand the muscle fiber gap to accommodate more immobilized water. However, the fiber was looser at the initial stage of stewing and then became more compact. PRACTICAL APPLICATION: This work demonstrates potentially feasible to produce salt-reduced duck products.

Synergetic effects of matrix components and diagenetic processes on pore properties in the Lower Cambrian shale in Sichuan Basin, South China

Synergetic effects of matrix components and diagenetic processes on pore properties were investigated from macroscale to nanoscale. Methods were combined to explore shales selected from well J1 in South China, in terms of elements measurement, organic geochemistry analysis, X-ray diffraction, nuclear magnetic resonance and direct imaging observation (2D wide horizon and 3D reconstruction). Three lithofacies were identified and porosity/permeability decrease in the order: authigenic siliceous shale > detrital clastic-rich shale > carbonate-rich shale. Further, different porous properties among lithofacies can be detected via image stitching technology, to achieve compatibility of large vision and high resolution. In this way, pore parameters are intuitively linked to related matrixes, which facilitates the elaboration of internal relationship between properties of pores and diagenetic mechanisms of matrixes. Authigenic siliceous shale is characterized by small pore size distribution (30–60 nm), high SEM-based surface porosity (6.04%) and good connectivity rate (60.66%), which is attributed to authigenic quartzes providing pre-existing frameworks and abundant OM contributing pore volumes. Detrital clastic-rich shale is characterized by broad pore size distribution (20–600 nm), moderate SEM-based surface porosity (3.09%) and fair connectivity rate (27.84%), since abundant detrital grain and lean OM trigger the domination of inorganic-related pore which are isolated with large diameters and small amounts. Carbonate-rich shale is characterized by small pore size distribution (10–100 nm), low SEM-based surface porosity (0.77%) and poor connectivity rate (12.86%), due to strong compaction, intensive cementation and limited OM migration. Even with similar geological history, diverse pore types and porous properties can be detected among the three lithofacies, which may attribute to different matrix components and their diagenetic processes. At over-mature stage, brittle minerals (quartz and calcite/dolomite) control OM distribution and prevent secondary pores from compaction. Whereas, ductile matrixes (clay and OM) provide the dominant pore volumes. Especially, OM can facilitate connectivity with porous attribute and migrating ability.

Effect of Dynamic Imbibition on the Development of Ultralow Permeability Reservoir

To explore the methodology for improving ultralow permeability reservoir recovery, cores of ultralow permeability reservoirs in China’s Ordos Basin were selected to study the dynamic imbibition micromechanism of crude oil in nanopore throat through core-flooding laboratory experiment and nuclear magnetic resonance (NMR) observation. In the meantime, the microimbibition characteristics and dynamic discharge of oil between matrix and fracture in partially closed boundary reservoirs were simulated to utmostly reflect the actual reservoir conditions. Our findings suggest that dynamic imbibition between fracture and matrix serves the core technology for improving the recovery of ultralow permeability reservoirs, while the main factors affecting dynamic imbibition efficiency include wettability, permeability, injection rate, fracture, water huff and puff cycles, and soaking time. Wettability, in particular, weighs the most, and imbibition can take place either on water-wet rocks or transformed oil-wet rocks with an imbibition agent added in during the waterflooding process. Meanwhile, the higher the permeability is in place, the greater the dynamic imbibition recovery might achieve. The experiments indicate that the dynamic imbibition recovery of a fractured core is 16.26% higher than that of a nonfractured core. Additionally, fractures can not only enhance imbibition recovery but also accelerate the occurrence of dynamic imbibition. The optimal water injection rate of dynamic imbibition is 0.1 mL/min; the reasonable huff and puff cycle of the ultralow permeability reservoirs tends to be two to three cycles; the optimal soaking time of ultralow permeability reservoir is speculated to be 30 days. Finally, the field practice shows that after Stimulated Reservoir Volume (SRV) and dynamic imbibition in 5 horizontal wells in An83 oilfield, there is a remarkable drop in water cut and a noticeable rise in oil production. This research underpins the significance of a dynamic imbibition effect in the development of ultralow permeability oilfield.

Recent progress in solid-state nuclear magnetic resonance of half-integer spin low-γ quadrupolar nuclei applied to inorganic materials.

An overview is presented of recent progress in the solid-state nuclear magnetic resonance (NMR) observation of low-γ nuclei, with a focus on applications to inorganic materials. The technological and methodological advances in the last 20years, which have underpinned the increased accessibility of low-γ nuclei for study by solid-state NMR techniques, are summarised, including improvements in hardware, pulse sequences and associated computational methods (e.g., first principles calculations and spectral simulation). Some of the key initial observations from inorganic materials of these nuclei are highlighted along with some recent (most within the last 10years) illustrations of their application to such materials. A summary of other recent reviews of the study of low-γ nuclei by solid-state NMR is provided so that a comprehensive understanding of what has been achieved to date is available.

Effect of sulfate on C-S-H at early age

The effect of increasing sulfate contents on the hydration of white cement was studied with a multi-technique approach. Quantitative X-Ray Diffraction (XRD) revealed that adding more gypsum in the cement resulted in more ettringite formation. Combining isothermal calorimetry, advanced in-situ 1H nuclear magnetic resonance (NMR) and early scanning electron microscopy (SEM) observations, it was possible to correlate the depletion of the gypsum with a change in C-S-H morphology, from needle-like to agglomerated C-S-H, together with a change in C-S-H gel pore content. Nevertheless, the content of C-S-H interlayer water remained similar and no change in C-S-H pore sizes were observed when increasing the sulfate content. The data allowed to calculate the volume composition of hydrated cement pastes at 3 days of hydration. The more gypsum was added to the cement, the lower was the bulk C-S-H volume due to lower gel pore content and the higher was the content of capillary porosity.

Thermal effects versus spin nematicity in a frustrated spin- 12 chain

The spin-nematic phase is an intriguing state of matter that lacks usual long-range dipolar order, yet it exhibits higher multipolar order. This makes its detection extremely difficult and controversial. Recently, nuclear magnetic resonance (NMR) has been proposed as one of the most suitable techniques to confirm its existence. We report a $^{17}$O NMR observation of the reduction of the local magnetization in the polarized state of the frustrated spin-1/2 chain $\beta$-TeVO$_4$, which was previously proposed to be a fingerprint of the spin-nematic behavior. However, our detailed study shows that the detected missing fraction of the magnetization, probed by NMR frequency shift, is thermally activated, thus undermining the presence of the spin-nematic phase in the investigated compound. This highlights the importance of careful considerations of temperature-dependent NMR shift that has been overlooked in previous studies of spin nematicity.

Efficient and green catalytic degradation of high crosslinked rigid PU foam and recovery value-added products via selective cleavage of C–O and C–N bonds

The degradation and recovery of waste rigid polyurethane foam (RPUF) have confronted enormous challenge because of its three-dimensional network. An efficient strategy was developed for chemical recycling of high value-added aromatic polyamines and polyether polyols via selective cleavage of carbamate and urea bonds from RPUF and characterized by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Ray (FT-IR). The carbamate and urea bonds were readily cleaved using (NH2)2CO/CH3CH2OH as degradation system at 180 °C for 10 h. Nevertheless, the C–C bonds and C–O–C of ether linkages as framework structure remained intact in the degradation process. Eventually, the high value-added products including aromatic polyamines and polyether polyols were retrieved. A feasible mechanism for degradation was proposed based on the NMR observations.

Emergent Prethermalization Signatures in Out-of-Time Ordered Correlations.

How a many-body quantum system thermalizes-or fails to do so-under its own interaction is a fundamental yet elusive concept. Here we demonstrate nuclear magnetic resonance observation of the emergence of prethermalization by measuring out-of-time ordered correlations. We exploit Hamiltonian engineering techniques to tune the strength of spin-spin interactions and of a transverse magnetic field in a spin chain system, as well as to invert the Hamiltonian sign to reveal out-of-time ordered correlations. At large fields, we observe an emergent conserved quantity due to prethermalization, which can be revealed by an early saturation of correlations. Our experiment not only demonstrates a new protocol to measure out-of-time ordered correlations, but also provides new insights in the study of quantum thermodynamics.

Surface nuclear magnetic resonance observations of permafrost thaw below floating, bedfast, and transitional ice lakes

Lakes in Arctic systems contribute to hydrologic storage, biogeochemical cycling, and permafrost thaw. Here, we have used surface nuclear magnetic resonance (NMR) measurements on lakes of Alaska’s North Slope to investigate the extent of permafrost thaw below lakes with different annual ice conditions. Our purpose is to understand if annual lake ice conditions are related to development of thawed permafrost below lakes. We investigated 10 lakes and two terrestrial permafrost control sites using surface NMR and direct measurement under spring conditions when lake ice is nearly at its thickest. We did not observe unfrozen water below our surveyed bedfast ice lakes, whereas unfrozen water (indicating permafrost thaw) was measured below floating ice lakes. We found that transitional ice lakes, ones that alternate between floating and bedfast ice conditions over multiyear timescales depending on winter ice growth and lake level conditions, have complex vertical unfrozen water content profiles attributed to sporadic periods of thaw. Based on that finding, we speculate that predicting the presence of talik based on remotely sensed lake ice conditions is unreliable. We applied a scheme to subtract the lake water signal from the NMR data and found the resulting inversions to be improved.

Observation of Discrete-Time-Crystal Signatures in an Ordered Dipolar Many-Body System.

A discrete time crystal (DTC) is a robust phase of driven systems that breaks the discrete time translation symmetry of the driving Hamiltonian. Recent experiments have observed DTC signatures in two distinct systems. Here we show nuclear magnetic resonance observations of DTC signatures in a third, strikingly different system: an ordered spatial crystal. We use a novel DTC echo experiment to probe the coherence of the driven system. Finally, we show that interactions during the pulse of the DTC sequence contribute to the decay of the signal, complicating attempts to measure the intrinsic lifetime of the DTC.