Anomalous Characteristics Research Articles

Temporal and spatial changes in the b-value prior to the 2021 Luxian M S 6.0 earthquake in Sichuan, China

Using the seismic data collected since 2010 by the China Earthquake Networks Center and based on the maximum likelihood method, we analyzed the temporal and spatial anomalies of the b-value prior to the M S 6.0 Luxian earthquake on September 16, 2021. The results are as follows. (1) The Luxian earthquake broke the historical record of no M ≥ 6 earthquake occurring in the Huayingshan fault zone, revealing that the Huayingshan fault zone still has the seismogenic ability of medium and strong earthquakes. (2) Before the M S 6.0 Luxian earthquake, the b-values around the focal areas exhibited increasing–peaking–decreasing anomalous characteristics, indicating that this is an effective method of predicting the occurrence of moderate to strong earthquakes in the region. (3) In the past 10 years, the b-values of the middle segment of the Huayingshan fault zone have been relatively low, but the b-value of this section may be in an abnormal stage of slow increase, indicating that this segment may be in a stage of stress accumulation and concentration and is preparing for moderate to strong earthquakes. The middle segment of the Huayingshan fault zone may become the site of moderate to strong earthquakes in the future. We should continue to pay attention to it.

Boosting the photoresponse speed of visible-light-active bismuth ferrite thin films based on Fe-site substitution strategy and favorable heterostructure design

Although BiFeO3 (BFO) is regarded as one of up-and-comingferroelectric oxides in the field of semiconducting devices due to its anomalous optoelectronic characteristics, is it possible to exploit its potential in the application of photodetection in visible band (Vis)? To answer this question, we firstly follow therecognized strategy of Fe-site substitution by involving zinc ions in BFO, i.e. synthesize BiFe1-xZnxO3 (BFZO) by sol–gel technique and successfully shrink its energy bandgap (Eg) from 2.3 eV of pure BFO down to circa 2.0 eV; moreover, we innovatively integrate hole-transporter NiO and constitute BFZO/NiO heterostructure to further accelerate charge carrier transitions. Going through systematical investigation on Eg and leakage current of BFZO films with Zn ratio optimization, as well as energy band alignment between BFZO and NiO, the splendid photo-response speed of BFZO/NiO heterojunction is achieved. The best response time constants of photocurrent rising and decay are optimized to 0.36 ms and 0.49 ms, which are two order-of-magnitude faster than pure-BFO/NiO and one order-of-magnitude faster than single BFZ0.8O film. Such neo-heterojunction has overwhelming photoresponse properties compared to other congeneric BFO/metal-ion-doped-BFO photodetectors reported elsewhere. Hereby, it portends a promising future of conventional wide-bandgap ferroelectric oxides in the application of up-to-date high-speed Vis detection.

Anomalous electrical performance of A-site double-bivalent-doped Bi0.49Na0.5TiO3- ceramics from nominal oxygen deficiency to excess

Perovskite structural Bi 0.5 Na 0.5 TiO 3 (BNT) ferroelectrics can exhibit considerable ionic conductivity, giving a new area for the application as oxygen ion conductors. Through acceptor doping and A-site nonstoichiometry, an ionic conductive mechanism associated with well-resolved arcs in the complex impedance spectra is proposed. Different dielectric responses in ceramics can be deduced to probe the electrical inhomogeneities in separative regions, such as bulk, grain boundary, and electrode, regions. Generally, ionic conductivity only arises at the nominal oxygen deficiency composition of BNT based ceramics. Although large current leakage can exist in the BNT ferroelectrics, they overall display an insulative nature and dominate the electronic conductive contribution, and only a large main arc can be identified in the Nyquist plots. In this work, A-site bivalent doped Bi 0.49- x (SrBa) x Na 0.5 TiO 3- δ and Bi 0.49- x (SrCa) x Na 0.5 TiO 3- δ ceramics ranging from oxygen deficiency to excess are investigated. However, anomalous ionic conductive characteristics are achieved at nominal oxygen excess composition. Herein, the polarization and conductive mechanisms are discussed to elucidate the effect of compositions and their phase and microstructure on the AC impedance, dielectric, and ferroelectric performances. The inhomogeneous distribution of oxygen vacancies, resulting from element segregation or distorted phases in the respective electroactive domains, is a crucial issue in the design of BNT based dielectrics or ionic conductors.

On the anomalous diffusion of proton in Y-doped BaZrO3 perovskite oxide

Proton transport in perovskite oxides (ABO3) is a complex dynamical process involving hydroxide ion rotation and proton transfer. Combining ab initio molecular dynamics (AIMD) and machine-learning molecular dynamics (MLMD) simulations of proton dynamics in Y-doped BaZrO3 perovskite oxide, we systematically illustrate the anomalous characteristics of proton motion. At short times, proton performs superdiffusion through the OH wag and proton transfer. At intermediate times, the larger rotation angle results in the larger plateau value. At longer times, proton diffusion first becomes subdiffusive due to the hydroxide ion rotations then gradually turns to normal diffusion. A theoretical model is also offered to quantitatively describe this abnormal proton diffusion. In all, this work provides a more complete understanding of proton dynamics in perovskite oxides.

Diagnosing anomalous characteristics of atmospheric water cycle structure during seasonal-scale drought events: A case study in middle and lower reaches of Yangtze River

Anomalous characteristics of the atmospheric water cycle structure are highly significant to the mechanisms of seasonal-scale meteorological droughts. They also play an important role in the identification of indicative predictors of droughts. To better understand the causes of seasonal meteorological droughts in the middle and lower reaches of the Yangtze River (MLRYR), characteristics of the atmospheric water cycle structure at different drought stages were determined using standardized anomalies. The results showed that the total column water vapor (TCWV) was anomalously low during drought occurrence periods. In contrast, there were no anomalous signals at the drought persistence and recovery stages in the MLRYR. Moreover, there was no significant temporal correlation between the TCWV anomaly and seasonal-scale drought index (the 3-month standardized precipitation index (SPI3)). During drought events, water vapor that mainly originated from the Bay of Bengal was transported southwest of the MLRYR. Meanwhile, the anomalous signal of water vapor transport was negative at the drought appearance stage. At the drought persistence stage, the negative anomalous signal was the most significant. Water vapor flux divergence in the MLRYR showed significant positive anomalous signals during drought events, and the signal intensity shifted from an increasing to a decreasing trend at different drought stages. In addition, a significant positive correlation existed between the anomaly of water vapor flux divergence and regional SPI3. Overall, water vapor flux divergence is more predictive of droughts in the MLRYR.

Statistical Global Investigation of Pre-Earthquake Anomalous Geomagnetic Diurnal Variation Using Superposed Epoch Analysis

Recent studies reported that the diurnal variation of the geomagnetic field exhibited anomalous characteristics several months before earthquakes (EQs). However, the statistical significance of such anomalies detected using the diurnal variation range ratio (DVRR) method still requires verification as only a limited number of EQs occurring in certain seismoactive zones were included. In this study, the DVRR method was employed in conjunction with the superposed epoch analysis (SEA) to perform a large-scale study. A total of 157 EQs that occurred between 2000 and 2019 were investigated using vast geomagnetic field data collected from 92 ground-based magnetometer stations spread across multiple global regions. The case study conducted on the May 13, 2011, M6.1 Honshu (Japan) EQ showed that the diurnal variation of the vertical geomagnetic component disappeared around a week before the EQ. The case study also demonstrated the effectiveness of the DVRR method in minimizing solar disturbance influences, further proving that the observed anomalies were not caused by the Sun. The subsequent SEA revealed statistically significant increases in anomaly counts before the occurrence of EQs for all three geomagnetic components. The number of anomalies gradually increased approaching the day of EQs with temporal lags between the components. Furthermore, a control group analysis confirmed the findings by demonstrating that the increases were not coincidental and several explanations have been suggested, focusing primarily on the emergence and generation mechanisms of the anomalies. Results from this study showed that the anomalies were significant and were potentially precursors to the succeeding EQs.

Split dynamic mechanical relaxation of an inhomogeneous dielectric and the insights into its anomalous characteristics

The split relaxations of an inhomogeneous polymer were investigated in this paper, with special attention paid to the application of classic dynamic mechanical analysis (DMA) to inhomogeneous dielectrics. The single relaxation peak of the pristine epoxy resin split to two peaks after thermal ageing, concerning its transition toward an inhomogeneous skin-core structure. Moreover, the relaxation corresponding to the skin-layer, which only took up a small proportion in volume, anomalously dominated the entire relaxation response. The core-layer’s response was even unidentifiable when its proportion was below 65 vol%. This was found strongly correlated with the non-uniform distribution of applied stress during DMA test which kinetically affected the viscoelastic response received from the specimen. Since potential misjudgment could be induced in this case, it should be a critical issue deserving more attention.

Enabling Automatic Detection of Anomalies in Wastewater: A Highly Simplified Approach to Defining “Normal” in Complex Chemical Mixtures

Wastewater treatment demands management of influent conditions to stabilize biological processes. Generally wastewater collection systems lack advance warning of approaching water parcels with anomalous characteristics, which could then be diverted for testing or pre-treatment. A major challenge in achieving this goal is identifying anomalies against the complex chemical background of wastewaters. This work evaluates unsupervised clustering methods to characterize “normal” wastewater characteristics, using >17 months of 10-min resolution absorbance spectrometry data collected at an operating wastewater treatment facility. Comparison of results using K-means, GMM, Hierarchical, and DBSCAN clustering shows minimal intra-cluster variability achieved using K-means. The four K-means clusters include three representing 99% of samples, with the remaining cluster (<0.3% of samples) representing atypical measurements, demonstrating utility in identifying both underlying modalities of wastewater characteristics and outliers. K-means clustering provides a better separation than grouping based on factors such as month, precipitation, or flow (with 25% overlap at 1-σ level, compared to 93, 93, and 83%, respectively) and enables identification of patterns that are not visible in factor-driven grouping, e.g., shows that summer and November months have a characteristic type of behavior. When evaluated with respect to wastewater influent changes occurring during the SARS-CoV-2 pandemic, the K-means approach shows a distinct change in strength of diurnal patterns when compared to non-pandemic periods during the same season. This method may therefore be useful both as a tool for fast anomaly detection in wastewaters, contributing to improved infrastructure resilience, as well for providing overall analysis of temporal patterns in wastewater characteristics.

Contributions of biofilm-induced flow heterogeneities to solute retention and anomalous transport features in porous media

Microbial biofilms are ubiquitous within porous media and the dynamics of their growth influence surface and subsurface flow patterns which impacts the physical properties of porous media and large-scale transport of solutes. A two-dimensional pore-scale numerical model was used to evaluate the impact of biofilm-induced flow heterogeneities on conservative transport. Our study integrates experimental biofilm images of Paenibacillus 300A strain in a microfluidic device packed with cylindrical grains in a hexagonal distribution, with mathematical modeling. Biofilm is represented as a synthetic porous structure with locally varying physical properties that honors the impact of biofilm on the porous medium. We find that biofilm plays a major role in shaping the observed conservative transport dynamics by enhancing anomalous characteristics. More specifically, when biofilm is present, the pore structure in our geometry becomes more spatially correlated. We observe intermittent behavior in the Lagrangian velocities that switches between fast transport periods and long trapping events. Our results suggest that intermittency enhances solute spreading in breakthrough curves which exhibit extreme anomalous slope at intermediate times and very marked late solute arrival due to solute retention. The efficiency of solute retention by the biofilm is controlled by a transport regime which can extend the tailing in the concentration breakthrough curves. These results indicate that solute retention by the biofilm exerts a strong control on conservative solute transport at pore-scale, a role that to date has not received enough attention.

A meteorological overview of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign over the southeastern Atlantic during 2016–2018: Part 1 – Climatology

Abstract. In 2016–2018, the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) project undertook 3-month-long deployments to the southeastern (SE) Atlantic Ocean using research aircraft to better understand the impact of biomass burning (BB) aerosol transport to the SE Atlantic Ocean on climate. In this (part 1 of the meteorological overview) paper, the climatological features at monthly timescales are investigated. The southern African easterly jet (AEJ-S), defined as the zonal easterlies over 600–700 hPa exceeding 6 m s−1 around 5–15∘ S, is a characteristic feature of the mid-level circulation over southern Africa that was also during the deployment months of August 2017, September 2016, and October 2018. Climatologically, the AEJ-S develops at lower altitudes (∼ 3 km; 700 hPa) between 5–10∘ S in August, while it develops at around 4 km (∼ 600 hPa) and further south (5–15∘ S) in September and October, largely driven by the strong sensible heating over the African plateau. Notable meteorological anomalous characteristics during the 3 deployment months, compared to climatology (2000–2018), include the following: (1) during August 2017, the AEJ-S was weaker than the climatological mean, with an additional anomalous upper-level jet aloft (∼ 6 km) around 10∘ S. August 2017 was also drier over the SE Atlantic at 600–700 hPa than climatology, with a stronger Benguela low-level jet (LLJ) at 925–950 hPa along the Namibian coast of the SE Atlantic. Consistent with this, the southern Atlantic anticyclone was also stronger and closer to the coast than the August climatological mean. (2) During September 2016, the AEJ-S intensity was similar to the climatological mean, although the heat low and vertical motion over the land was slightly stronger compared to the September climatology. The LLJ and the large-scale southern Atlantic anticyclone were stronger than the climatological mean. (3) During October 2018, the AEJ-S was slightly weaker compared to the climatological mean, as was the LLJ and the southern Atlantic anticyclone. October 2018 was wetter over the Benguela coastal region at 600 hPa than the climatological mean. During all the deployment months, the sea surface temperatures (SST) over the SE Atlantic were warmer than the climatological means, but the monthly mean low cloud fraction was only noticeably reduced in August 2017. A weak August 2017 AEJ-S can explain low offshore black carbon (BC) mixing ratios within the European Centre for Medium-Range Weather Forecasts (ECMWF) Copernicus Atmosphere Monitoring Service (CAMS) reanalysis, although the BC peak altitude, at 2–3 km, is below that of the AEJ-S. The upper-level wave disturbance and the associated anomalous circulation also explain the weakening of AEJ-S through the reduction of the strength of the heat low over the land during August 2017.

Применение алгоритма Isolation Forest для обоснования уникальности водоемов в группе карстовых озер

Improving the scientific foundations for the development and expansion of the network of specially protected natural areas requires the search for algorithms that could be used to identify unique ecosystems. Algorithmization of the anomaly identification process provides an opportunity not only to process large amounts of data but also leads to obtaining objective and comparable estimates. The purpose of this research is to identify the most optimal mechanisms for identifying anomalous values for the morphometric characteristics of karst lakes, which may indicate the uniqueness of the entire lake ecosystem. Within the framework of this article, the study was carried out based on a mathematical analysis of samples built for various characteristics based on the WORLDLAKE database. Statistical methods and the Isolation Forest (iForest) machine learning algorithm were used as methods of analysis. As a result of applying the iForest algorithm to a sample of morphometric parameters of karst lakes, consisting of 738 objects, 43 anomalous water bodies were identified. An expert assessment of the final set of lakes for the uniqueness of their ecosystems showed that the chosen method for identifying anomalous values is well suited for the task at hand. Many lakes with an anomaly index above 60% can be recognized as unique due to the unusualness of their abiotic characteristics; a number of them also have a peculiar biota. The anomalous objects included such well-known lakes as Tserik-Kol’, Crveno, Salda Lake, Trihonida, Vegoritida, Petron, etc. Moreover, for most of them, anomalies were detected for several parameters at once. Thus, the applied algorithm for identifying anomalous morphometric characteristics of lakes made it possible to obtain interesting samples for further expert analysis of the entire lake ecosystem for its uniqueness.

Anomalous Kinetic Characteristics of Hydrogen Transport through Pd–Cu Membranes Modified by Pentatwinned Flower-Shaped Palladium Nanocrystallites with High-Index Facets

Anomalous Kinetic Characteristics of Hydrogen Transport through Pd–Cu Membranes Modified by Pentatwinned Flower-Shaped Palladium Nanocrystallites with High-Index Facets

An Ionospheric Anomaly Monitor Based on the One Class Support Vector Algorithm for the Ground-Based Augmentation System

An ionospheric anomaly is the irregular change of the ionosphere. It may result in potential threats for the ground-based augmentation system (GBAS) supporting the high-level precision approach. To counter the hazardous anomalies caused by the steep gradient in ionospheric delays, customized monitors are equipped in GBAS architectures. A major challenge is to rapidly detect the ionospheric gradient anomaly from environmental noise to meet the safety-critical requirements. A one-class support vector machine (OCSVM)-based monitor is developed to clearly detect ionospheric anomalies and to improve the robust detection speed. An offline-online framework based on the OCSVM is proposed to extract useful information related to anomalous characteristics in the presence of noise. To validate the effectiveness of the proposed framework, the influence of noise is fully considered and analyzed based on synthetic, semi-simulated, and real data from a typical ionospheric anomaly event. Synthetic results show that the OCSVM-based monitor can identify the anomaly that cannot be detected by other commonly-used monitors, such as the CCD-1OF, CCD-2OF and KLD-1OF. Semi-simulation results show that compared with other monitors, the newly proposed monitor can improve the average detection speed by more than 40% and decrease the minimum detectable gradient change rate to 0.002 m/s. Furthermore, in the real ionospheric anomaly event experiment, compared with other monitors, the OCSVM-based monitor can improve the detection speed by 16%. The result indicates that the proposed monitor has encouraging potential to ensure integrity of the GBAS.

Rethinking the Characteristic Parameters of Typhoon Activity Frequency in the Western North Pacific

ABSTRACT Typhoons are among the most dangerous weather systems on earth and can cause devastating disasters. Although great improvements have been made in the prediction of typhoon tracks during the past decades, typhoon frequency remains a major challenge in operational forecasting and climate prediction. Typhoon genesis frequency focuses on the frequency of formation of a single typhoon. However, the accumulation of single typhoons cannot effectively represent the anomalous characteristics of the corresponding circulation because of considerable differences among the typhoons, such as life history, track, and intensity. The occurrence of multiple typhoons or a single typhoon lasting for a long time over a particular region is usually closely related to the atmospheric circulation over that region. Therefore, in this study, the frequency of typhoons during a certain period and region is used to measure typhoon activity in the western North Pacific (WNP). It is found that the variation of typhoon existence frequency is different from that of typhoon genesis frequency. Typhoon existence frequency greatly improves the connection between typhoon activity and large-scale air–sea interactions (such as the El Niño–Southern Oscillation) and can better indicate the difference in weather and climate corresponding to typhoon activity anomalies. Further investigation reveals that typhoon existence frequency in the WNP during typhoon season is closely related to the North Pacific tripole pattern of sea surface temperature (SST) anomaly (NPSST) and the SST anomaly along the eastern coast of Australia in the South Pacific (SPSST) in the spring (April). A regression model using the NPSST and SPSST indices in April as predictors proved to have good skill in predicting the existence frequency of typhoons in the WNP during typhoon season.

Sign-reversible valley-dependent Berry phase effects in 2D valley-half-semiconductors

Manipulating valley-dependent Berry phase effects provides remarkable opportunities for both fundamental research and practical applications. Here, by referring to effective model analysis, we propose a general scheme for realizing topological magneto-valley phase transitions. More importantly, by using valley-half-semiconducting VSi2N4 as an outstanding example, we investigate sign change of valley-dependent Berry phase effects which drive the change-in-sign valley anomalous transport characteristics via external means such as biaxial strain, electric field, and correlation effects. As a result, this gives rise to quantized versions of valley anomalous transport phenomena. Our findings not only uncover a general framework to control valley degree of freedom, but also motivate further research in the direction of multifunctional quantum devices in valleytronics and spintronics.

Sinuosity of Atmospheric Circulation over Southeastern China and Its Relationship to Surface Air Temperature and High Temperature Extremes

Linking sinuosity, a fairly recently developed metric, with high temperature extremes (HTEs) can be both useful and insightful to better understand the physical mechanisms behind HTEs. However, it is not clear whether there exists a relationship between the sinuosity changes and HTE changes in present and future climate conditions over southeastern China. In this paper, the anomalous characteristics of the atmospheric circulation are quantified by sinuosity. Three sinuosity metrics are used in this study: individual sinuosity (SIN), aggregate sinuosity (ASIN), and comprehensive sinuosity (CSIN). Furthermore, we examine the relationship between sinuosity changes and HTE changes in present and future climate conditions. ASIN is strongly correlated with surface air temperature (SAT). We find that the influence of individual sinuosity (SIN) at different latitudes on the SAT of southeastern China is different. The SIN of low (middle) latitude isohypses has significant positive (negative) correlations with the SAT of southeastern China. The SIN of high-latitude isohypses is rather limited and can therefore be ignored. The projected relationship between the sinuosity changes and HTE changes in the late 21st century suggests similar results. The change in SAT is related to the changes in climate variables over southeastern China in the future, and these changes increase with the increase in Z500 or V850 and the decrease in U500. Moreover, the frequencies of large (small) comprehensive sinuosity (CSIN) values at low (mid) latitudes will increase. At the end of the 21st century, Z500 isohypses at different latitudes will have an obvious poleward shift. Our results indicate that measuring the aggregate waviness of the midtropospheric flow (via sinuosity) can provide insight regarding HTEs, and the climate model output can be used to examine the future likelihood of increased HTE.

Influence of Liquid Inclusions to Explosive Instability of Ice

The influence of the nuclei of the liquid phase arising during mechanical deformations of polycrystalline ice at temperatures below -40 ... -45 C on its explosive instability is considered. The nucleus of the liquid phase appear in ice when part of the hydrogen bonds are broken when high pressure is applied to ice crystals. The resulting clusters can have characteristics close to those of bulk metastable water. It is known that such water in the region of negative temperatures has anomalous thermodynamic characteristics. In particular, at a temperature of -60 C and a pressure of 100 MPa, there is a second critical point of water for the liquid-liquid transition. It was found that the transition occurs between the two types of water LDL (low density water) and HDL (high density water), with the Widom line coming out into the one-component region of the water phase diagram. This line is the locus of increased fluctuations in entropy and density. Near atmospheric pressure, the temperature on the Widom line is -45 C. If the pressure inside the ice and its temperature turn out to be close to the line of coexistence of LDL and HDL, then liquid inhomogeneities can become a source of mechanical instability of the medium due to the growth of fluctuations in the energy of molecules and destruction of the ice structure. Such conditions can occur at temperatures below -45 C and pressures above 100 MPa.

MRET treated water as a tool to mitigate mRNA jab side effects: A review

The viral RNA (ribonucleic acid) was found in virtually every organ in the body, which means the spike proteins as well. There are antibodies (like the “vaccine” is supposed to create) but they’re irrelevant because, based on a study from Japan, we now know that the spike S1 protein is what does the damage. That means the spike proteins created by the mRNA will be in every organ as well, and we now know it is the spike proteins that do the damage. Another significant mRNA jab side effect was found by Israeli researchers. They discovered a link between Pfizer’s COVID-19 vaccine and a rare blood disease called thrombotic thrombocytopenic purpura (TTP). Any formation of proteins depends on Van der Waals interactions. The Van der Waals forces depend in its turn on dielectric property of the protein molecules and water since all biochemistry needs water environment. It is practically impossible to change dielectric property/electrical charge of the proteins, but it is quite easy to modify dielectric property of water. There are research data indicating relation between dielectric constant of the human body tissue (TDC) and temperature: 35° C - 74.9 F/m (TDC) and 40° C - 73.2 F/m (TDC). It shows that normal homeostasis of the human body is allowed at certain range of electrodynamic van der Walls interactions following the small range of tissue dielectric property about 75 - 73 F/m. It allows us to suggest that dielectric property of human body tissue is very important physiological parameter. Considering mentioned above ideas, it allows us to hypothesize that most of biochemical proteins building mechanisms in a healthy human body require certain physiological range “window” of van der Waals interactions and hydrogen bonding between proteins molecules and water - salt medium. In theory, this physiological “window” of van der Waals weak electromagnetic forces may be significantly different from the range of electrodynamic van der Waals interactions required for life sustains formations of DNA/RNA proteins of viruses. Thus, modification of water - based medium electrodynamic parameters of the human tissues that are favorable for the homeostasis of the body (in the range of physiological “window”) can lead to significant change of van der Walls interactions and hydrogen bonding that may result in the inhibition and interruption of proper formation of spike proteins chains. Such scenario obviously disables coronavirus life sequence of attachment and fusion with human cell membranes. We suggest such agent which can interrupt pathogenic microorganism’s life sequence is MRET (Molecular Resonance Effect technology) water with anomalous electrodynamic characteristics. MRET water can be consumed on the regular basis by human subjects to prevent infections of pathogenic microorganisms.

Magnesium Diffusion from MgO Substrates in Sol–Gel‐Derived NiO Epitaxial Films: Effects of Heat Treatment Temperature and Li Doping

The effects of heat treatment temperature and Li doping on the structural properties of sol–gel‐derived NiO epitaxial films on MgO (100) substrates are investigated. X‐ray diffraction measurements indicate that the out‐of‐plane lattice parameters of undoped NiO films increase as the heat treatment temperature increases. This increase is particularly significant in films treated above 900 °C, in which out‐of‐plane and in‐plane lattice parameters are larger than the expected values for bulk NiO. This result cannot be explained by the strain originating in the lattice mismatch between NiO and MgO. In addition, the bandgap drastically increases in undoped films treated above 900 °C. Secondary ion mass spectrometry depth profiling demonstrates that undoped films treated above 900 °C are Ni1−xMgxO alloys generated by the diffusion of Mg from MgO substrates into NiO films, resulting in the anomalous characteristics of the prepared films. Furthermore, it indicates that the diffusion of Mg is reduced in Li‐doped films, which can be explained on the basis of defect chemistry, in which Ni vacancies decrease with the increase in Li concentration. Consequently, the increases in the lattice parameter and bandgap at high heat treatment temperatures are reduced in Li‐doped films.

Large slip, long duration, and moderate shaking of the Nicaragua 1992 tsunami earthquake caused by low near-trench rock rigidity

Large earthquake ruptures propagating up to areas close to subduction trenches are infrequent, but when they occur, they heavily displace the ocean seafloor originating destructive tsunamis. The current paradigm is that the large seafloor deformation is caused by local factors reducing friction and increasing megathrust fault slip, or prompting the activation of ancillary faults or energy sources. As alternative to site-specific models, it has been proposed that large shallow slip could result from depth-dependent rock rigidity variations. To confront both hypotheses, here, we map elastic rock properties across the rupture zone of the M S7.0-M W7.7 1992 Nicaragua tsunami earthquake to estimate a property-compatible finite fault solution. The obtained self-consistent model accounts for trenchward increasing slip, constrains stress drop, and explains key tsunami earthquake characteristics such as long duration, high-frequency depletion, and magnitude discrepancy. The confirmation that these characteristics are all intrinsic attributes of shallow rupture opens new possibilities to improve tsunami hazard assessment.