Low-temperature Studies Research Articles (Page 1)

Tectonic and exhumation history of the Shillong plateau − Mikir Massif, NE India: Constraints from low-temperature thermochronological study

Theoretical study of low temperature anomaly in velocity of sound in cuprates

High pressure - low temperature study on NdBaMn2O6 double manganites

Rare earth thulium tri chloride (TmCl3) has consistent distribution of brick shaped, rectangular particles with monoclinic crystal structure and 92 nm crystallite size. Density of dislocation is 1.181 × 1014m-2 . The calculated strain is 3.788 × 10−4 . The refractive index is 3.067, and the energy gap is 5.26 eV. Optical studies on TmCl3 assigns energy level transitions. Low-temperature magnetic studies upto 20K have revealed intriguing phase transitions between 50 and 99K which may be paramagnetic to antiferromagnetic transition. Investigation of aqueous solution of TmCl3 exhibits wider potential window 2.86V indicating electrochemically superior nature of the electrolyte.

Perfluorooctanoic acid (PFOA) is a pervasive global pollutant, persisting in the atmosphere without natural degradation pathways and posing significant ecological and health risks. Using two surface-specific techniques, sum frequency generation (SFG) spectroscopy and surface excess coverage, we investigated changes in monolayers of PFOA and the non-halogenated analogue, octanoic acid (OA), at room and near-freezing temperatures. SFG spectra showed that OA monolayers were influenced only by bulk concentration, remaining less impacted by the temperature. PFOA monolayers are acidic at lower temperatures, regardless of the concentration. The temperature did not significantly impact the surface excess concentrations; however, changing the sample pH greatly influenced surface propensity, with acidic PFOA samples having twice the surface concentration as the deprotonated analogue, perfluorooctanoate (PFO-), samples at any temperature. These results reveal that pH plays a significant role in low-temperature studies and gives potential insight into the ice nucleation efficiency of PFOA.

Abstract Low-temperature thermochronology, including fission track (FT) and (U–Th–Sm)/He thermochronometry, has been widely used to constrain the exhumation history of orogenic systems over timescales of 106–108 years. This research employed simple numerical modeling to evaluate the applicability of low-temperature thermochronometry to young orogenic systems uplifted in geologically recent periods such as the Pliocene and Quaternary, such as those in the Japanese Islands. Such orogenic systems are at the younger limit of the applicability because this time scale corresponds to the younger limit of applicability of the major low-temperature thermochronometers and also corresponds to the minimum period required for an orogenic system to be denuded by more than ~ 2–3 km after the start of uplift, which is the lower limit detectable by the major low-temperature thermochronometers. Time‒temperature paths were generated for varying uplift rates, uplift onsets, and model onsets (equivalent to the rock formation age). These paths were then converted into cooling ages for four thermochronometers: apatite and zircon FT and (U–Th–Sm)/He dating. The calculations were conducted using two models: a constant-elevation model and an increasing-elevation model. The modeling results are summarized in look-up tables, illustrating relationships between uplift rates, uplift onsets, rock formation ages and ratios of cooling age and rock formation age. The results indicate that differences in formation age and elevation change minimally impact cooling ages. The modeled dates generally align with measured cooling ages in regions where the rate and timing of uplift are well constrained, supporting the reliability of the modeling approach. Consequently, the derived relationships between uplift rates and cooling ages provide a practical method for roughly classifying mountain uplift rates based on cooling ages, without requiring complex simulations. Finally, these relationships were applied to previously reported cooling ages to visualize the distribution of uplift rates across the Japanese Islands over the past few million years. These results provide a benchmark for the low-temperature thermochronological studies, not only in the Japanese Islands, but also in mobile belts around the world that have begun to uplift in the past few million years.

While the high energy densities and long cycle lifetimes of Li-ion batteries have enabled them to become an important form of energy storage, these properties are greatly diminished at lower temperatures.1 The battery electrolyte plays a key role in these performance reductions as many processes involving Li+ transport kinetics are negatively impacted by low temperatures.2 To mitigate the effects of operating Li-ion batteries in cold environments, researchers have put considerable effort into designing thermal management systems to prevent batteries from operating outside their optimized temperatures.3 While extensive work has been performed to understand and limit the effects of low temperatures on Li-batteries during operation, limited information exists on passive battery exposure to cold environments, particularly at more extreme temperatures where solidification of the electrolyte can occur. Thus, we employ micro-Raman spectroscopy to characterize the temperature-dependent, solidification dynamics of commercial, carbonate-based electrolytes (1 M LiPF6 in varied ratios of ethylene carbonate (EC) and dimethyl carbonate (DMC)). During electrolyte cooling, phase transitions for EC and DMC are observed which induce spatial heterogeneity in the electrolyte composition whereby some regions become solidified while others remain liquid with elevated concentrations of LiPF6. Such changes in the electrolyte composition may impact Li-ion batteries stored at low temperatures as well as batteries utilized in space applications where thermal management is transiently unavailable and may even impact batteries operated in cold environments in addition to the reductions in other temperature-dependent properties.References Petzl, M.; Kasper, M.; Danzer, M. A. Lithium plating in a commercial lithium-ion battery – a low-temperature aging study. J. Power Sources 2015, 275, 799–807.Hubble, D.; Brown, D. E.; Zhao, Y.; Fang, C.; Lau, J.; McCloskey, B. D.; Liu, G. Liquid electrolyte development for low-temperature lithium-ion batteries. Energy Environ. Sci. 2022, 15, 550–578.Kim, J.; Oh, J.; Lee, H. Review on battery thermal management system for electric vehicles. Appl. Therm. Eng. 2019, 149, 192–212.

The precision control over the directional crystallization of low-dimensional solids enables access to 0D, 1D, and 2D nanoscale morphologies with physical properties that are drastically altered from its parent, bulk structure. However, these synthetic processes are often limited by the lack of directionality and anisotropy that can be used as a means to modulate crystallization dynamics, especially in non-thermodynamic conditions. In this talk, I will discuss our efforts in demonstrating how the quasi-1D sublattice of an anisotropic 2D van der Waals (vdW) crystal, like GaTe, can be harnessed to generate 1D nanowires in the absence of any catalyst or substrate modification. We demonstrate that precise control over the diffusion and deposition rates in our growth conditions yields ultrathin nanostructures that preserve the native, direct band gap monoclinic structure. The resulting nanostructures crystallized in either the thermodynamically favored nanosheet morphology or the kinetically favored nanowire morphology that reached thicknesses down to 10 ± 5 nm. We show using low-temperature photoluminescence studies confinement into ultrathin nanowires result in unusually enhanced photoluminescence with peaks possessing narrow linewidths in the technologically important near-IR region. These anisotropic 1D GaTe nanowires that display remarkably strong emissive behavior hold promise for use in densified and miniaturized optical and optoelectronic devices as stand-alone building blocks or as coupled with other 1D and 2D vdW materials.

Lithium plating is a key degradation mechanism which results from operating in cold temperatures (or high C-rates) and can ultimately contribute to catastrophic failure of lithium-ion batteries via short circuit. Predicting the onset of lithium plating via non-invasive methods could allow for Battery Management Systems to modify cell operating conditions to minimise cell degradation and extend cell lifetime. In order to detect lithium plating reliably, the dependence between reversible and irreversible lithium plating must be understood better. This work aims to address this gap by analysing the relaxation voltage response after individual vs. successive charge pulses.Examining the behaviour of lithium-ion batteries at extreme cold temperatures enhances visual features associated with lithium plating. A two-plateau relaxation voltage occurs following a constant-current charge pulse (of sufficiently high C-rate), with the lower plateau corresponding to the expected open circuit voltage. Several authors [1-5] have reported this feature and attributed it to lithium stripping. It has been identified in both cold [1], and room temperature after a fast charge [2]. Schindler et al. [3] differentiated the relaxation profile to quantify a ‘time period’ (differential voltage relaxation analysis, DVRA) and showed an inverse exponential relationship between ‘time period’ and the magnitude of the lithium stripping current. Von Lüders et al. [4] used in-situ neutron diffraction to determine the amount of lithium stripped during relaxation, finding a linear relationship with the ‘time period’. Mei et al. [5] used graphite half-cells, proposing that: the upper plateau indicates that lithium plating dominates, the lower plateau indicates that intercalation dominates, while the mixed potential region marks the transition where the two phenomena compete. There is very little consensus in the literature regarding whether the ‘time period’ can be attributed to the amount or rate of lithium being stripped.This work focuses on interpreting features in the voltage profile indicative of lithium plating, by using the commercial 21700 cylindrical cell Molicel P45B. This cell is particularly suitable for low temperature studies, as it is rated for discharge down to -40°C. For different temperatures, we compare cell voltage features for individual pulses around different SOC’s and C-rates to those for successive pulses (GITT charge protocol, Figure B), for cells at beginning of life and during degradation (Figure B and C). The ‘time period’ of fresh cell voltage relaxation is found to be larger than that of the degraded cell. This indicates that a fresh cell is subject to either relatively more reversible lithium plating or a slower rate of lithium stripping during relaxation. In addition to examining the ‘time period’ as an indicator of reversible plating, degradation mode analysis (DMA) is used to quantify the amount of irreversible plating. The impact of cell state of health and heat generation on the quantification of lithium plating/stripping from DVRA is studied on a cell with a thermocouple inserted into its core, thus rendering core-to-surface thermal gradients measurable.This study has provided significant detail to our understanding of the conditions which cause reversible and irreversible plating, and the impact these have on cell performance and lifetime. Non-invasive detection of lithium plating and stripping remains a challenge, as DMA and DVRA reveal that reversible and irreversible lithium plating are coupled. The DVRA ‘time period’ results are affected by cell degradation: they cannot be a useful indicator of reversible plating in the absence of carefully controlled cell history and degradation quantification.

Abstract The present work investigated the mixed crystal structure of multiferroic material Yb0.9Sr0.1MnO3 and studied the influence of nanocrystalline size on its physical properties. The X-ray and neutron diffraction analysis of Yb0.9Sr0.1MnO3 reveals a mixed orthorhombic/hexagonal phase. The average crystallite size observed from XRD and SEM analysis is ~ 70–85 nm. The orthorhombic phase, characterized by a space group Pnma (No. 62), decreases from 45 to 5% with heat treatment, while quantity of the hexagonal phase characterized by a space group P6 3 cm (No.185) increases accordingly. It is found that the lattice parameters of hexagonal crystal system at room temperature are a = b = 6.06479Å, c = 11.42647Å, γ = 120° and the orthorhombic one are a = 5.390Å, b = 7.5440Å and c = 5.430Å. Two antiferromagnetic ordering temperature points of Yb0.9Sr0.1MnO3 are observed near 87 K and 120 K, attributed to C-type antiferromagnetic ordering and Γ2-type antiferromagnetic ordering, respectively. The magnetic moment of the Γ2 antiferromagnetic phase was deduced to be 3.4μB/Mn at 2.5 K. The magnetic moment of the C-type antiferromagnetic phase was found to be 1.2μB/Mn at 2.5 K. A theoretical model describing the magnetization as a function of crystal structure and temperature, based on the Monte Carlo simulation is presented. The internal energy was calculated based on the Ising model, a crucial part of the methodology. The magnetization behavior exhibits a first-order phase transition at low H while a second-order phase transition at high H. Theoretical calculations not only confirmed but also validated the experimental results and their interpretation, providing a solid foundation for the study.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [specify authors given name] Last name [specify authors last name]. Also, kindly confirm the details in the metadata are correct.Ok

The liquid crystalline compound, forming the glass of the smectic CA* phase, is investigated by X-ray diffraction in the 18-298 K range. The characteristic distances within the smectic CA* phase are determined, and the specific volume is estimated. The electron density profile along the smectic layer normal is inferred and compared with the results of the density functional theory calculations. Observations of the selective reflection of the visible light investigate the helical ordering within the smectic CA* glass. The results indicate slow change with temperature of the smectic layer spacing, intermolecular distances, and electron density distribution below the glass transition temperature. The change in the temperature dependence of the specific volume is well below the glass transition temperature. Meanwhile, the relative range of the short-range order within the smectic layers and the helix pitch are rather constant in the glassy state.

Abstract The properties and creation of optical centers in diamond are essential for applications in quantum technology. Here, we study the photoluminescence (PL) spectroscopy behavior at low temperatures of diamond subjected to electron irradiation and annealing heat treatment. Through temperature variation testing, it was found that the NV− center intensity of diamond with a nitrogen content of 150 ppm before treatment is insensitive to the experimental temperature, but significantly increases with decreasing temperature after treatment, showing sensitivity to temperature. In addition, the H3 center also shows an increasing trend with decreasing temperature. The results of annealing diamond with a nitrogen content of 730 ppm showed that even at a low temperature of 93 K, no NV− centers were detected, but there were a large number of Ni-N related centers, especially NE8 centers. Our findings can promote a deeper understanding of the behavioral characteristics of HPHT-diamond optical centers in low-temperature environments.

Post-mineralization processes and preservation of porphyry deposits controlled by regional tectonic events: A comparative low-temperature thermochronology study of the Hadamiao and Bilihe porphyry Au deposits, north China

Calcium sulfate minerals are found in multiple environments on Earth and Mars, with chloride (Cl) salts widely distributed on both planets. Low-temperature studies have explored geochemical processes, including the formation of transient liquid water and ion migration on Mars. Some Cl-salts (e.g., NaCl and CaCl2) can dissolve gypsum (CaSO4·2H2O) in certain environments, making gypsum-Cl salt interactions significant. Additionally, gypsum's geochemical transformation at high temperatures reveals dehydration pathways crucial for understanding Mars' aqueous history and potential for life. This study examines gypsum dehydration through (i) thermal analyses and (ii) interactions with Cl-salts over a temperature range of -90 to 400 °C. We applied three spectroscopic techniques (Raman, visible/near-infrared, and mid-IR) plus X-ray diffraction (XRD) to analyze these samples under variable conditions. This study also provides a low-temperature spectral data set for gypsum and gypsum-Cl salt mixtures, beneficial for orbital analyses. Our findings reveal that experimental (i) heating rates, (ii) temperature ranges, (iii) relative masses of gypsum and Cl-salts, and (iv) dehydration environments (e.g., in situ and in vacuo) influence Ca-sulfate phase formation. Although we find different results in some cases, this study demonstrates that changing experimental conditions affects the detectability and transformation of gypsum. Further, these results indicate that the geochemical environmental conditions on Mars play a role in gypsum's geochemical transformation to dehydrated components. This study also provides structural and chemical data for Ca sulfate assemblages from vibrational spectroscopy and XRD, which extends our knowledge of gypsum and related materials under variable conditions, thus aiding orbital and surface planetary analyses that may help to advance our understanding of planetary geochemistry on Mars.

It has been found that hetero layers of typical β-ZnSe and atypical α-ZnSe modifications can be obtained by the isovalent substitution method. Isovalent impurities are formed which predetermine the formation of dominant radiation with a quantum yield of η = 12–15% in the short wavelength edge region. Low-temperature studies and λ-modulation techniques allowed us to identify the radiation components. This radiation is generated by interband recombination and exciton annihilation. The high temperature stability of the radiation was confirmed over temperature variations including 77, 300, and 480 K.

Low-temperature fabrication, magnetoresistance and spin pumping studies of polycrystalline few-layer 1T’-MoTe2 films

After undergoing biological treatment, wastewater still contains substances with endotoxic activity, such as lipopolysaccharide. However, due to the increasing practice of treating wastewater to make it suitable for drinking (potable reuse), the removal of these endotoxic active materials is crucial. These substances can be harmful to human health, leading to a condition called endotoxaemia. Furthermore, environmental endotoxins pose risks to pharmaceutical manufacturing processes and the quality of the final pharmaceutical products. Ultimately, the most significant concern lies with the patient, as exposure to such substances can have adverse effects on their health and well-being. Activated carbon has a proven efficiency for endotoxin removal; rice husk (RH), as a type of natural lignocellulosic agricultural waste, is a unique carbon precursor material in terms of its availability, large-scale world production (over 140 million tons annually), and is characterized by the presence of nanoscale silica phytoliths, which serve as a template to create additional meso/macropore space within the nanoscale range. High surface area RH/lignin-derived honeycomb monoliths were prepared in this study via extrusion, followed by carbonization and physical and chemical activation to develop additional pore space. The nanoporosity of the carbon honeycomb monoliths was established by means of low-temperature nitrogen adsorption studies, using calculations based on QSDFT equilibrium and BJH models, as well as mercury intrusion porosimetry (MIP) and SEM investigations. An alternative method for the elimination of the bacterial lipopolysaccharide (LPS)-a conventional marker-using filtration in flowing recirculation systems and the adsorbent activity of the monoliths towards LPS was investigated. Since LPS expresses strong toxic effects even at very low concentrations, e.g., below 10 EU/mL, its removal even in minute amounts is essential. It was found that monoliths are able to eliminate biologically relevant LPS levels, e.g., adsorption removal within 5, 30, 60, 90, and 120 min of circulation reached the values of 49.8, 74.1, 85.4, 91.3%, and 91.6%, respectively.

Negative Magnetization and Spin-Phonon Coupling in Faceted Nd2FeCrO6 Double Perovskite

Exhumation response to oceanic plateau accretion and oroclinal bending: Low-temperature thermochronology study of Wrangellia terrane on southern Vancouver Island, Canada

Episodic cooling of the Hannan-Micangshan Dome at the northern margin of the Yangtze Block, Central China: Response to progressive convergence in the eastern Tethys since the Mesozoic