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In ultrawide bandgap (UWBG) nitride and oxide semiconductors, increased bandgap (Eg) correlates with greater ionicity and strong electron–phonon coupling. This limits mobility through phonon scattering, localizes carriers via polarons and self-trapping, broadens optical transitions via dynamic disorder, and modifies the breakdown field. Herein, we use polarized optical transmission spectroscopy from 77 to 633 K to investigate the Urbach energy (Eu) for many orientations of Fe- and Sn-doped β-Ga2O3 bulk crystals. We find Eu values ranging from 60 to 140 meV at 293 K and that static (structural defects plus zero-point phonons) disorder contributes more to Eu than dynamic (finite temperature phonon-induced) disorder. This is evidenced by lack of systematic Eu anisotropy, and Eu correlating more with x-ray diffraction rocking-curve broadening than with Sn-doping. The lowest measured Eu are ∼10× larger than for traditional semiconductors, pointing out that band tail effects need to be carefully considered in these materials for high field electronics. We demonstrate that, because optical transmission through thick samples is sensitive to sub-gap absorption, the commonly used Tauc extraction of a bandgap from transmission through Ga2O3 >1–3 μm thick is subject to errors. Combining our Eu(T) from Fe-doped samples with Eg(T) from ellipsometry, we extract a measure of an effective electron–phonon coupling that increases in weighted second order deformation potential with temperature and a larger value for E||b than E||c. The large electron–phonon coupling in β-Ga2O3 suggests that theories of electrical breakdown for traditional semiconductors need expansion to account not just for lower scattering time but also for impact ionization thresholds fluctuating in both time and space. [ABSTRACT FROM AUTHOR]

Influence of chemical composition on the bandgap of AlGaInAs deposited on InP is often calculated using models for unstrained composition and then corrected for strain-induced bandgap energy changes using deformation potentials. This method relies on up to 25 coefficients, many of which are burdened with large uncertainty. In this paper, a large set of experimental data is used to verify the accuracy of existing approaches and to search for optimal deformation potentials. It is shown that the main source of inaccuracy is not the deformation potentials, but the unstrained bandgap formulas. Additionally, a novel model is proposed, yielding the highest accuracy on our dataset. For the first time, composition determination of a quaternary alloy on InP is reported using inductively coupled plasma-optical emission spectrometry, which is used as a benchmark for modeling. [ABSTRACT FROM AUTHOR]

Monolayer HfSe2, in the family of transition metal dichalcogenides (TMDCs), is a potential thermoelectric candidate due to its low thermal conductivity. While its mobility remains low as in other 2D TMDCs is inconceivable for electronic and thermoelectric applications. Earlier theoretical attempts have failed to give justification for the orders of low experimental mobility obtained for monolayer HfSe2. We calculate the carrier mobility in the framework of the density functional perturbation theory in conjunction with the Boltzmann transport equation and correctly ascertain the experimental value. We also calculate the carrier mobility with the previously employed method, the deformation potential (DP) model, to figure out the reason for its failure. We found that it is the strong electron-optical phonon interaction that is causing the low mobility. As the DP model does not account for the optical phonons, it overestimates the relaxation time by an order of two and also underestimates the temperature dependence of mobility. A strong polar type interaction is evidenced as a manifestation of a discontinuity in the first derivative of the optical-phonons at the K and Γ points as well as a dispersive optical phonon at the K point. We also included the spin–orbit coupling which leads to an energy splitting of ∼330 meV and significantly affects mobility and scattering rates. [ABSTRACT FROM AUTHOR]

In this work, we study the rectification and optimization of the transport of Brownian particles in deformable channels, both numerically and analytically. It should be noted that particle transport via channels encompasses a wide range of phenomena, such as osmosis and the passage of ions through ionic channels, particle separation, modeling the movement of dilute mixtures of microscopic particles, and so on. Throughout all of this, the volume of the point particles moving through the channel is determined by the geometry of the latter. To ensure the confinement of particles during their displacement in a deformable channel, we applied the reflection condition. The Remoissenet–Peyrad deformable potential generates a novel appealing and simple deformable channel with a shape parameter r. As such, we may change the geometry of the potential well and the potential barrier, which can be thin or wide, as well as the depth, height, and opening of the channels entrance. Characteristics that affect the systems efficiency. In the absence of an external force, the particles move due to thermal agitation and eventually achieve a condition of equilibrium where they are virtually uniformly distributed in the channels cells. They move faster or less swiftly in the presence of external forces, depending on the strength and direction of the force, as well as their mass and thermal agitation. Moreover, it appears to have a symmetry related to the shape of the channel for nonlinear mobility, effective diffusion coefficient, and efficiency of rectification. [ABSTRACT FROM AUTHOR]

Background: Digital image correlation (DIC) is widely used as a noncontact optical deformation measurement method. However, optical DIC encounters difficulties when measuring displacement and strain at high temperatures, including false deformation caused by heat haze and image overexposure caused by intense thermal radiation. X-ray imaging is not affected by these factors, so the combination of X-ray imaging and the DIC algorithm (X-DIC) holds the potential for measuring deformation during high-temperature tests. Objective: This study investigated the ability of X-DIC to measure deformation in high-temperature experiments, expand the applicable temperature range of X-DIC, and provide a reliable method for obtaining deformation measurements in high-temperature experiments. Methods: A combination of X-ray digital radiography (DR) images and the DIC algorithm was used to measure deformation. Numerical experiments based on synthetic images were used to evaluate the measurement accuracy of X-DIC, and the influence of different DIC parameters on the measurement error was discussed. Ductile iron and C/SiC composites were subjected to tensile tests at different temperatures from ambient temperature to 1000 °C, and different deformation measurement methods were used to simultaneously measure the deformation of the samples to verify the accuracy of the X-DIC results. Results: In the numerical experiments, the displacement measurement error of X-DIC is less than 0.02 px. The relative error between the X-DIC and blue-light DIC measurements of the tensile deformation of ductile iron at 500 °C is 0.65%. When the deformation of the C/SiC composite materials was measured at 1000 °C, the root mean square error (RMSE) of the strain data obtained by X-DIC and optical DIC was 1.12 × 10–4. Conclusions: These results prove that X-DIC has high measurement accuracy. Compared with optical DIC, X-DIC is insensitive to high-temperature environments and provides alternative experimental methods for high-temperature deformation measurements. [ABSTRACT FROM AUTHOR]

Background: In the mechanical testing of high-temperature structural materials, ultra-high temperature deformation measurement is very necessary and very challenging. Objective: To overcome the challenge of using single-camera stereo-digital image correlation (stereo-DIC) for ultra-high-temperature measurement. Methods: An ultraviolet single-camera stereo-DIC system combining active UV illuminations, an ultraviolet camera, a single UV narrow bandpass filter, a reflective prism and two reflectors was established. In addition, two types of high temperature speckle patterns were prepared A tensile test of C/C composites at 2600 °C was conducted to verify the effectiveness and accuracy of the developed technology. Results: The ultraviolet single-camera stereo-DIC system has excellent resistance to thermal radiation. As well, the two types of speckle patterns are available at 2600 °C. And the values of elastic modulus calculated by the developed technology and high-temperature extensometer are very close to each other, and the relative errors are less than 7%. Conclusions: The well matched strain results with high-temperature extensometer data demonstrates that the ultraviolet single-camera stereo-DIC is an effective ultra-high temperature deformation measurement technology and has great potential in characterizing the deformation response of materials at ultra-high temperatures. [ABSTRACT FROM AUTHOR]

Strain engineering serves as an effective method for optimizing electronic and optical properties in semiconductor devices, with applications including the enhancement of optical emission in Ge and GeSn‐based devices, improvement of carrier mobility, and second harmonic generation in silicon photonics structures. Current methods for deformation characterization in semiconductors, such as X‐ray diffraction and Raman spectroscopy, often require bulky and expensive setups and are limited in vertical resolution. Consequently, techniques capable of measuring lattice strain while overcoming these drawbacks are highly desirable. This study proposes a proof of concept for a cost‐effective, compact, fast, and non‐destructive approach to probe non‐uniform strain fields and additional material properties by exploiting the bulk photovoltage effect. The method is benchmarked with an array of silicon nitride stripes deposited under varying pressure conditions on a germanium substrate. Initially, their surface strains are verified through Raman spectroscopy. The deformations are replicated in a finite element method platform by integrating mechanical simulations with deformation potential theory, thereby estimating the band edge energy landscape. Finally, the study discusses the theoretical behavior of the photovoltage signal, considering semiconductor properties, defects, doping, and deformation. The findings offer insights into the development of advanced techniques for strain and transport analysis in semiconductor materials. [ABSTRACT FROM AUTHOR]

Earthquake-induced crustal deformation provides valuable insights into the mechanisms of tectonic processes. Dislocation models offer a fundamental framework for comprehending such deformation, and two-dimensional antiplane dislocations are used to describe strike-slip faults. Previous earthquake deformation analyses observed that antiplane dislocations due to uniform fault slips are influenced predominantly by fault tips. Here, we state a general principle of fault geometry invariance in antiplane dislocations and exploit its theoretical consequence to define dislocation potentials that enable a streamlined crustal deformation analysis. To demonstrate the benefits of this theory, we present an analytical example and construct a rapid numerical solver for crustal deformation caused by variable fault slip scenarios using physics-informed neural networks, whose mesh-free property is suitable for modeling dislocation potentials. Fault geometry invariance and the dislocation potential may further the analysis of antiplane crustal deformation, particularly for uncertainty quantification and inversion analysis regarding unknown fault geometries in realistic crustal structures. [ABSTRACT FROM AUTHOR]

Piezoelectricity is a well-known effect in a vast number of technologically important insulators and semiconductors and exists in 20 out of the 32 three-dimensional crystal classes. The piezoelectric effect is the driving mechanism behind several classical sensors and transmitters, and also most recently, in many nanodevices. Zhong Lin Wang coined the fields piezotronics and piezo-phototronics where the piezoelectric effect plays a dominant role. Piezoelectricity couples in a linear fashion mechanical strain to electrical fields and vice versa. In solids, there is another linear coupling between strain and the electric potential, known as the deformation potential effect. While linear in its coupling nature, this effect does not require the solid to be non-centrosymmetric in contrast to the piezoelectric effect. Moreover, the deformation potential effect is quantitatively huge and leads to changes in the conduction and valence band edges of III–V and II–VI materials of, typically, 50–100 meV in the presence of 1 % strain. Therefore, the deformation potential effect is essential to determine the electronic and photonic properties of bulk and nanostructure semiconductors in the presence of strain. In this work, we compute the relative importance of piezoelectricity and the deformation potential effect in the presence of lattice mismatch and external strain. We choose p − n junctions of ZnO/GaN structures but anticipate that the general conclusions can be carried over to other material structures. The main result of the present work is that both the inclusion of the deformation potential effect and piezoelectricity is crucial to correctly compute the effect of strain on p − n junction current–voltage curves and photonic properties. In our analysis of wurtzite heterostructures, the spontaneous polarization effect is also included but this effect appears to play a minor role for electronic and photonic properties. [ABSTRACT FROM AUTHOR]

The shrinkage behavior of compacted clays is crucial for evaluating deformation and failure potentials in subgrade and earth dam engineering. A series of soil shrinkage and nuclear magnetic resonance tests were performed on the same specimen for a wide range of compacted clays under drying condition. The correlation between soil shrinkage on the macroscale and pore water evolution on the microscale was thoroughly investigated. The experimental results show that structural shrinkage depends on the initial structure of compacted clay, while the impact of compaction density on basic and residual shrinkages is relatively minimal. The distribution of the transverse relaxation time T2 in a saturated specimen effectively indicates the transitional water content from the structural to basic shrinkage using the NMR technique. Furthermore, a nearly identical maximum T2 could serve as the characteristic time for identifying the other transitional water content between basic and residual shrinkage stages in compacted clays. Two transitional water contents in the shrinkage curve and Atterberg limits are highly correlated, indicating a potential method for estimating the soil shrinkage curve of compacted clays using fundamental soil properties. [ABSTRACT FROM AUTHOR]

Large-scale man-made linear structures like high-speed railway lines have become increasingly important in modern life as a faster and more comfortable transportation option. Subsidence or longitudinal levelling deformation problems along these railway lines can prevent the line from operating effectively and, in some cases, require speed reduction, continuous maintenance or repairs. In this study, the longitudinal levelling deformation of the high-speed railway line passing through Konya province (Central Turkey) was analyzed for the first time using the Persistent Scatter Synthetic Aperture Radar Interferometry (PS-InSAR) technique in conjunction with diagnostic train measurements, and the correlation values between them were found. In order to monitor potential levelling deformation along the railway line, medium-resolution, free-of-charge C-band Sentinel-1 (S-1) data and high-resolution, but paid, X-band Cosmo-SkyMed (CSK) Synthetic Aperture Radar (SAR) data were analyzed from the diagnostic train and reports received from the relevant maintenance department. Comparison analyses of the results obtained from the diagnostic train and radar measurements were carried out for three regions with different deformation scenarios, selected from a 30 km railway line within the whole analysis area. PS-InSAR measurements indicated subsidence events of up to 40 mm/year along the railway through the alluvial sediments of the Konya basin, which showed good agreement with the diagnostic train. This indicates that the levelling deformation of the railway and its surroundings can be monitored efficiently, rapidly and cost-effectively using the InSAR technique. [ABSTRACT FROM AUTHOR]

Mining operations disrupt the structure of rock layers, leading to surface deformations and potential mining damage. This issue has been extensively studied since the 19th century using various analytical, geometric-integral, and stochastic methods. Since the 1990s, numerical methods have been increasingly applied to determine changes in the stress and strain states of rock masses due to mining activities. These methods account for numerous additional factors influencing surface deformation, offering significant advantages over classical approaches. However, modelling rock masses presents challenges, particularly in calibrating the mechanical parameters of rock layers, an area extensively researched with numerous publications. In this study, we determined the mechanical parameter values of rock layers at the advancing mining front using a custom Python script and Finite Element Method (FEM) numerical models. We also introduced a modification to evaluate the error of the estimated parameter values. Numerical analyses were conducted for the Piast–Ziemowit mine region in Poland, utilizing mining, geological, and surveying data. Our results demonstrate that accurate calibration of mechanical parameters is crucial for reliable predictions of surface deformations. The proposed methodology enhances the precision of numerical models, providing a more robust framework for assessing the impact of mining activities on rock layers. [ABSTRACT FROM AUTHOR]

High and steep dangerous rock masses (DRMs) along reservoir banks pose significant threats to navigation and the adjacent towns. Taking the Longmen DRM (LDRM) in the Three Gorges reservoir area as an example, this paper analyzed the geological background and focused on the No.5 DRM of LDRM (LDRM-5) to investigate deformation characteristics and potential failure mechanisms. Furthermore, the rockslide tsunami risk of LDRM-5 was assessed. LDRM-5 is a typical pillar-shaped DRM with a distinct binary structure prone to sliding. Its boundaries are well-defined. The lower part of LDRM-5, situated within the reservoir fluctuation zone, comprises fragmented thin-layered argillaceous limestone with Karst breccia interlayer, and was considered to control the stability of the steep slope directly. In the future, the base rock of LDRM-5 might collapse due to long-term erosion from fluctuating reservoir water and constant pressure from the slope above, potentially resulting in overall slope failure. A granular flow model was employed to assess the tsunami risk posed by LDRM-5. Results show that the rockslide-generated tsunami exhibits greater propagation velocity at the water level of 175 m, while displaying a higher wave height at 145 m water level. At 145 m water level, the tsunami run-up on the opposite bank can reach 24.3 m, posing an extremely high-risk area covering 102.55 × 104 m2 and threatening a riverbank stretch of 16.03 km. At 175 m water level, the extremely high-risk area decreases to 45.31 × 104 m2, endangering a 7.85 km riverbank stretch. This study can provide a reference for research on failure mechanisms and tsunami risks of other high-steep DRMs in reservoir areas. [ABSTRACT FROM AUTHOR]

First-principles simulations were conducted to explore various electronic properties of crystalline SiO2 (α-quartz) under ultrafast laser irradiation. Employing Density Functional Perturbation Theory and the many-body (GW) approximation, we calculated the impact of thermally excited electrons on the electronic specific heat, electron pressure, effective mass, deformation potential, electron-phonon coupling and electron relaxation time of quartz, covering a wide range of electron temperatures, up to 100,000 K. We show that the electron-phonon relaxation time of highly-excited quartz becomes twice faster compared to low-excited states. The deformation potential, which dictates atomic displacement, has a non-monotonic behavior with a well-pronounced minimum at around 16,000 K (2.7 × 1021 cm−3 of excited electrons) where the bond ionicity of the Si-O starts decreasing followed by a cohesion loss at 35,000 K due to the pressure exerted by the excited electrons on the lattice. Consequently, our calculated data, illustrating the evolution of physical parameters, can facilitate simulations of laser-matter interactions and provide predictive insights into the behavior of quartz under experimental conditions. [ABSTRACT FROM AUTHOR]

Landslide hazards pose a significant threat to lives and infrastructure, especially in mountainous regions like the Three Gorges Reservoir area. While the mechanisms driving landslide initiation and progression in reservoir environments are not fully understood. This study aimed to leverage the capabilities of Sentinel-1 satellite imagery and the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique to detect and monitor potential landslide deformations in Yunyang County, Chongqing, China. We utilized Sentinel-1 data acquired between January 1, 2020, and December 28, 2022, to generate deformation velocity maps. Twelve potential landslides were identified, primarily concentrated near residential areas and along the Yangtze River. Precipitation emerged as the primary driver of surface deformation and landslide initiation, with potential landslides in residential vicinities and along the river exhibiting significantly higher deformation rates during the wet season compared to the dry season. These sites are susceptible to slope failures and geological disasters upon reaching critical antecedent rainfall thresholds, highlighting the necessity for continuous monitoring. Other potential landslides maintained consistent deformation rates across seasons but experienced brief accelerations following heavy precipitation events. Notably, potential landslides adjacent to the Yangtze River experienced accelerated deformation during periods of significant river water level reductions, suggesting that the river's cyclical water level fluctuations influence slope stability. The study demonstrated the effectiveness of SBAS-InSAR in detecting millimetric deformations in incipient landslides, a crucial step in averting landslide disasters and ensuring public safety. [ABSTRACT FROM AUTHOR]

When it comes to hydropower dam safety, continuous and comprehensive monitoring is increasingly important. Especially for aging dams, this can pose a difficult challenge that benefits from a multimethod analysis. Here, we present the use and suitability of a geophysical method, Ground Penetrating Radar (GPR), for the non-invasive assessment of two distinct types of hydropower dams in Romania: Herculane (a concrete arch dam) and Gura Apelor (an embankment dam with a rockfill and clay core). Unlike traditional monitoring methods for dam safety in Romania, which might provide an incomplete overview, GPR offers a broader, non-destructive approach to evaluating some elements of dam integrity. Here, we present the results of surveys carried out with a 200 MHz antenna on the crests of both dams. The aim was to conduct a rapid assessment of the crest condition and identify the potential damage to the crest that may elude standard monitoring techniques. The surveys provide an imaging indicative of the structural integrity, although this is more challenging in the embankment dam, and additionally we provide significant information regarding the deformations in the upper layers. This complements data from routine topo-geodetical surveys, offering a potential explanation for the vertical displacements observed therein. We highlight several areas of potential deformation as well as degradation in subsurface structures such as rebars. The results underscore the value of GPR in supplementing established dam monitoring methods, highlighting its effectiveness in different contexts and dam types, as well as its potential in shaping future standards for dam safety management in Romania. [ABSTRACT FROM AUTHOR]

The realization of a harmonious relationship between the natural environment and economic development has always been the unremitting pursuit of traditional mineral resource-based cities. With rich reserves of iron and coal ore resources, Laiwu has become an important steel production base in Shandong Province in China, after several decades of industrial development. However, some serious environmental problems have occurred with the quick development of local steel industries, with ground subsidence and consequent secondary disasters as the most representative ones. To better evaluate possible ground collapse risk, comprehensive approaches incorporating the common deformation monitoring with small-baseline subset (SBAS)-synthetic aperture radar interferometry (InSAR) technique, environmental factors analysis, and risk evaluation are designed here with ALOS PALSAR and Sentinel-1 SAR observations. A retrospect on the ground deformation process indicates that ground deformation has largely decreased by around 51.57% in area but increased on average by around −5.4 mm/year in magnitude over the observation period of Sentinel-1 (30 July 2015 to 22 August 2022), compared to that of ALOS PALSAR (17 January 2007 to 28 October 2010). To better reveal the potential triggering mechanism, environmental factors are also utilized and conjointly analyzed with the ground deformation time series. These analysis results indicate that the ground deformation signals are highly correlated with human industrial activities, such underground mining, and the operation of manual infrastructures (landfill, tailing pond, and so on). In addition, the evaluation demonstrates that the area with potential collapse risk (levels of medium, high, and extremely high) occupies around 8.19 km2, approximately 0.86% of the whole study region. This study sheds a bright light on the safety guarantee for the industrial operation and the ecologically friendly urban development of traditional steel production industrial cities in China. [ABSTRACT FROM AUTHOR]

This article presents an analysis of thermal deformations in a large-scale vertical Lathe, examining the sources of heat and their impact on the machine's thermal deformations. The analysis was conducted using both experimental measurements and numerical simulations based on the finite element method. The study highlights the critical role of geometric accuracy, stiffness, and thermal distortions in machine tool design, affecting machining errors. Several machine tool manufacturers implement systems that minimize the impact of thermal distortions using numerical control. However, custom production lacks extensive possibilities, posing challenges in achieving requirements for predictable thermal distortions. This article analyzes the thermal distortions of a custom-produced machine tool and examines their values and consistency with the machine tool's working components' movement. The study emphasizes the predictability and directionality of thermal distortions in large-sized machine tools to maintain geometric accuracy and stiffness. Additionally, the study identifies non-technical aspects related to the division of the worktable into component parts, disrupting the axial symmetry of the construction and causing potential deformations of the workpiece due to thermal deformations. [ABSTRACT FROM AUTHOR]

We investigate the non-adiabatic effect of time-dependent deformations in the Milky Way (MW) halo potential on stellar streams. Specifically, we consider the MW's response to the infall of the Large Magellanic Cloud (LMC) and how this impacts our ability to recover the spherically averaged MW mass profile from observation using stream actions. Previously, action clustering methods have only been applied to static or adiabatic MW systems to constrain the properties of the host system. We use a time-evolving MW–LMC simulation described by basis function expansions. We find that for streams with realistic observational uncertainties on shorter orbital periods and without close encounters with the LMC, e.g. GD-1, the radial action distribution is sufficiently clustered to locally recover the spherical MW mass profile across the stream radial range within a |$2\sigma$| confidence interval determined using a Fisher information approach. For streams with longer orbital periods and close encounters with the LMC, e.g. Orphan–Chenab (OC), the radial action distribution disperses as the MW halo has deformed non-adiabatically. Hence, for OC streams generated in potentials that include an MW halo with any deformations, action clustering methods will fail to recover the spherical mass profile within a |$2\sigma$| uncertainty. Finally, we investigate whether the clustering of stream energies can provide similar constraints. Surprisingly, we find for OC-like streams, the recovered spherically averaged mass profiles demonstrate less sensitivity to the time-dependent deformations in the potential. [ABSTRACT FROM AUTHOR]

Understanding ultrafast response of a semiconductor is necessary for next-generation optoelectronic device applications. Here, we investigate the ultrafast response of an archetypal semiconductor Ge [111] crystal upon photoexcitation at two pump wavelengths, 800 nm (fundamental) and 400 nm (second harmonic, UV radiation), using time-resolved x-ray diffraction (TXRD). The simulated TXRD profiles using a proposed four-layer model and Takagi–Taupin equations reveal that the strain propagation is primarily due to electron diffusion. Intriguingly, the initial (<100 ps) fast decrease in the induced strain for second harmonic excitation suggests that the strain originates from the deformation potential (DP) effect. The higher photon energy (second harmonic pump) excites the electrons to higher conduction band valleys, resulting in DP-induced strain compared to the fundamental pump, which only generates thermo-elastic strain. The DP strain, estimated from the DP coefficient (simulated via density functional theory-based electronic structure simulations) and electron density (simulated from experimental results), shows an excellent agreement with the observed strain. The strain after ∼100 ps delay for second harmonic excitation and strain from fundamental excitation are attributed to the thermo-elastic effect as confirmed by the density-dependent two-temperature model. Our study reveals the long-lasting DP effect in Ge [111], which provides an opportunity to avoid heating in optoelectronic devices due to the thermo-elastic effect at the initial time scale. [ABSTRACT FROM AUTHOR]

Hg 1 − x Cd x Te alloys are unique because by increasing the Cd content x, one modifies the band structure from inverted to normal, which fundamentally modifies the dispersion of bulk, surface or edge (in the case of quantum wells) energy states. Using alloys with x close to the concentration xc at which the band inversion transition is observed and with additional application of hydrostatic pressure (p), one creates a favorable playground for studying the evolution of Dirac matter and its topological properties. In this work, cryogenic magnetospectroscopy in quantizing magnetic fields (B) in the far-infrared is used to study inter-Landau-level transitions in high-quality Hg 1 − x Cd x Te MBE-grown epitaxial layers with x ≈ x c as a function of p up to 4.2 kbar. Special attention is paid to elucidate the role of the substrate and buffer layers, which usually modify the pressure coefficients of epitaxial layers. For this purpose, comparative measurements were carried out on as-grown epilayers with a GaAs substrate and on free-standing layers obtained by etching off the substrate. Spectra registered as a function of B (at given p) were analyzed with the help of the Kane model modified to include magnetic field. The pressure coefficient as well as the difference between conduction and valence band deformation potentials of the free-standing layer were determined at 2 K. Surprisingly, the deformation potentials and pressure coefficients of the epitaxial layer and those of the free-standing layer differed by no more than 10% in the pressure range up to 4.2 kbar. This finding questions the common belief of a dominant influence of the substrate on the pressure coefficients of epitaxial layers. We attribute the smallness of this difference to the presence of a highly disordered CdTe buffer separating the substrate from the epitaxial layer, which relaxes the transmission of strain from the substrate to the layer. Our results contribute to a better understanding of pressure experiments carried out on epitaxial layers on a substrate. [ABSTRACT FROM AUTHOR]

This study evaluates metallic yield dampers, specifically slit steel dampers, for protecting steel beam-to-column connections during seismic events. Finite element model simulations were conducted for the damper and its connection. Analysis of circular parameters, like the radius slot, showed that appropriately sized slit dampers exhibit advantageous seismic behavior. Moment-rotation, hysteresis curves, and plastic stresses comparisons indicate efficient energy absorption. The maximum moment was 25% lower than conventional samples. The slit steel damper model with a ductility factor of 3.5 allows significant plastic deformation before potential failure. Results emphasize the slit damper's potential for optimal performance in steel frames, suggesting its use for efficient energy absorption. [ABSTRACT FROM AUTHOR]

Presently it is important to remove mechanically disturbed layer on wafer surface during creation of up-to-date microelectronic products. Rapid thermal treatment with optical pulses of second duration is one of the applicable methods for removing disturbances in crystal lattice emerging after ion implantation. However the crystal structure of mechanically disturbed layer on wafer planar side is still unclear. Researches by transmission electronic method, analysis of diffraction reflection curve and electronic Auger spectroscopy has failed to provide reliable data about the state of crystal lattice in surface layer of at least 30 nm thickness. Hence it was impossible to suggest a model of solid phase recrystallization and to present its mathematical description. The goals of the work were as follows: – identify of silicon crystal lattice state in surface layer of 30 nm thickness before and after rapid thermal treatment by backward reflected electrons diffraction method using raw Si wafers surface; – analysis of contamination element composition on the surface of raw silicon before and after rapid thermal treatment; – model development for solid phase recrystallization of surface disturbed layer after rapid thermal treatment and its mathematical description. Images of back ward reflected electrons diffraction using surface layer of raw silicon wafers' of 30 nm thickness and also the results of the planar surface of raw silicon wafers' cleaning from impurities are provided. Processes reducing the activating energy of mechanically disturbed silicon layer recrystallization process were suggested and its mathematical description was provided. Parameters of rapid thermal treatment mitigating the thermal impact on silicon wafer for recrystallization of mechanically disturbed layer on its planar surface ware defined.

Highlights Glass fiber reinforced polymer (GFRP) composite tubes have become increasingly popular in crashworthiness applications. On the other hand, square section GFRP tubes are prone to damage in a catastrophic failure mode in the early stages of the crushing process. At this point, triggering mechanisms have great potential to ensure deformation in progressive mode and improve the compression performance of GFRP tubes. Motivated by these facts, this paper aims to optimize the compression performance of square GFRP tubes by implementing notch‐type triggering mechanisms. The effects of notch width, number and length on the axial compression response of tubes were investigated to determine the optimal trigger configurations that would maximize specific energy absorption (SEA) and minimize peak crushing force (PCF). Experiments were conducted based on Taguchi L9 orthogonal array design, and Taguchi coupled Weighted Aggregated Sum Product Assessment (WASPAS) method was employed for optimizing multiple responses. The optimization results revealed that the proposed trigger mechanisms induced progressive crushing by preventing catastrophic failure, thereby significantly improving the compression performance of GFRP tubes. In particular, the results showed that the PCF of intact GFRP tube decreased by up to 38%, while SEA increased by up to 130% with the help of proposed trigger mechanism. The compression performance of square GFRP tubes improved by notch‐type triggering. The notch width, length and number were chosen as design parameters. Taguchi experimental design was used to find the best configuration of design parameters. The optimum configurations were examined through the entropy‐WASPAS approach. The results revealed that significant improvements can be achieved using trigger mechanism. [ABSTRACT FROM AUTHOR]

The optical image sub-pixel correlation (SPC) technique is an important method for monitoring large-scale surface deformation. RapidEye images, distinguished by their short revisit period and high spatial resolution, are crucial data sources for monitoring surface deformation. However, few studies have comprehensively analyzed the error sources and correction methods of the deformation field obtained from RapidEye images. We used RapidEye images without surface deformation to analyze potential errors in the offset fields. We found that the errors in RapidEye offset fields primarily consist of decorrelation noise, orbit error, and attitude jitter distortions. To mitigate decorrelation noise, the careful selection of offset pairs coupled with spatial filtering is essential. Orbit error can be effectively mitigated by the polynomial fitting method. To address attitude jitter distortions, we introduced a linear fitting approach that incorporated the coherence of attitude jitter. To demonstrate the performance of the proposed methods, we utilized RapidEye images to extract the coseismic displacement field of the 2019 Ridgecrest earthquake sequence. The two-dimensional (2D) offset field contained deformation signals extracted from two earthquakes, with a maximum offset of 2.8 m in the E-W direction and 2.4 m in the N-S direction. A comparison with GNSS observations indicates that, after error correction, the mean relative precision of the offset field improved by 92% in the E-W direction and by 89% in the N-S direction. This robust enhancement underscores the effectiveness of the proposed error correction methods for RapidEye data. This study sheds light on large-scale surface deformation monitoring using RapidEye images. [ABSTRACT FROM AUTHOR]

The creep characteristics and potential deformation patterns of gangue backfill material are crucial in backfill mining operations. This study utilizes crushed gangue from the Gangue Yard in Fuxin City as the research material. An in-house designed, large-scale, triaxial gangue compaction test system was used. Triaxial compaction creep tests were conducted on gangue materials with varying particle size distributions. Analysis was performed based on different particle sizes, stresses, and confinement pressures. The study investigates the creep characteristics of the gangue under different conditions and explores the underlying causes. It reveals the relationship between the creep deformation of gangue materials and the passage of time. Mathematical methods are applied to develop a triaxial compaction creep power law model for gangue backfill materials. Finally, the creep results are fitted using an empirical formula approach. [ABSTRACT FROM AUTHOR]

The stable MnS monolayer was recently predicted using first-principles density functional theory (DFT) including Hubbard U (DFT+U) correction and Monte Carlo (MC) simulations. It is shown to exhibit an indirect band gap of 0.68 eV semiconductor with a high Neel temperature (TN) of 720 K and an in-plane easy axis magnetic anisotropy energy (MAE). The considered on-site Hubbard U correction takes into account only the Mn (3d) localized nature. To correct the intersite errors due to strong hybridization between bonded Mn (3d) and S (2p) states, the Hubbard +V inter-site parameter should be added to the calculations. In this study, the band gap of MnS is found to be increased to 1.24 eV (twice that for DFT+U) after considering the inter-site V correction (DFT+U+V). Since the MnS monolayer prefers an in-plane easy axis for the MAE, the estimated Berezinskii Kosterlitz Thouless transition (BKT) transition temperature is as high as 1667.8 K. The carrier mobility is calculated based on the deformation potential and effective mass and it is found that holes (2.12 cm²v-1S-1) are twice the size of these electrons (1.21 cm²v-1S-1). The results are expected to improve the potential of the MnS monolayers in multiple AFM spintronic device applications. [ABSTRACT FROM AUTHOR]

In bridge structure monitoring and evaluation, deformation data serve as a crucial basis for assessing structural conditions. Different from discrete monitoring points, spatially continuous deformation modes provide a comprehensive understanding of deformation and potential information. Terrestrial laser scanning (TLS) is a three-dimensional deformation monitoring technique that has gained wide attention in recent years, demonstrating its potential in capturing structural deformation models. In this study, a TLS-based bridge deformation mode monitoring method is proposed, and a deformation mode calculation method combining sliding windows and surface fitting is developed, which is called the SWSF method for short. On the basis of the general characteristics of bridge structures, a deformation error model is established for the SWSF method, with a detailed quantitative analysis of each error component. The analysis results show that the deformation monitoring error of the SWSF method consists of four parts, which are related to the selection of the fitting function, the density of point clouds, the noise of point clouds, and the registration accuracy of point clouds. The error caused by point cloud noise is the main error component. Under the condition that the noise level of point clouds is determined, the calculation error of the SWSF method can be significantly reduced by increasing the number of points of point clouds in the sliding window. Then, deformation testing experiments were conducted under different measurement distances, proving that the proposed SWSF method can achieve a deformation monitoring accuracy of up to 0.1 mm. Finally, the proposed deformation mode monitoring method based on TLS and SWSF was tested on a railway bridge with a span of 65 m. The test results showed that in comparison with the commonly used total station method, the proposed method does not require any preset reflective markers, thereby improving the deformation monitoring accuracy from millimeter level to submillimeter level and transforming the discrete measurement point data form into spatially continuous deformation modes. Overall, this study introduces a new method for accurate deformation monitoring of bridges, demonstrating the significant potential for its application in health monitoring and damage diagnosis of bridge structures. [ABSTRACT FROM AUTHOR]

The dynamics of a three-layer dome with a discrete-symmetric lightweight reinforced with ribs under a concentrated impact on its top was studied. The study explores the behavior of a three-layer dome, uniquely designed with discrete, symmetrically placed, lightweight ribs for reinforcement, when subjected to a concentrated impact at its apex. The supporting layers of the dome are made with different thicknesses. Each supporting layer of the dome differs in thickness, offering a complex structure for analysis. In the analysis of the elements of the elastic structure, the Timoshenko model of the theory of shells and rods was used under independent static and kinematic hypotheses for each layer. According to the Hamilton–Ostrogradsky variational principle, the equations of motion of asymmetric three-layer hemispherical shells with a discrete-symmetric lightweight rib-reinforced aggregate under axisymmetric local impulse loading were obtained. An appropriate finite element model of the shell was created, which reflects the relationship between the potential energy of deformations in the body and the potential of applied forces. A detailed finite element model was developed to capture the interplay between the dome's deformation energy and the force applied, facilitating a nuanced exploration of the dome's dynamic response. The numerical results of the study of the dynamics of a three-layer elastic structure with asymmetric thickness based on the finite element method were obtained The influence of geometrical and physical–mechanical parameters of asymmetric layers of a spherical dome on its dynamic behavior during a concentrated impact on its top was studied and new mechanical effects were investigated. Through numerical analysis, the dome's asymmetrical layer thickness and the physical and mechanical characteristics of these layers were examined to determine how they influence the dome's reaction to concentrated impacts. This investigation reveals novel mechanical behaviors and underscores the significance of geometrical and material properties in the dome's dynamic performance [ABSTRACT FROM AUTHOR]

LiteBIRD is a space mission aimed to measure the polarization signal of the cosmic microwave background (CMB). One of the telescopes of LiteBIRD is the low-frequency telescope which has two aluminum reflectors. The reflectors are designed with thin surfaces to minimize the weight of the reflectors. Due to the thinness of the surfaces, there is a potential risk of deformation due to machining and thermal stresses. We need to establish the fabrication methodology to achieve the required surface accuracy and maintain it throughout the operation period. This paper describes the fabrication and prototyping of the half-scaled reflector and the evaluation of the surface accuracy as a demonstration. We confirmed that we can achieve an accuracy of the reflector surface of less than 10 μ m RMS. Additionally, the deformation after the thermal cycle test was less than 2 μ m RMS. These meet our requirements for CMB observation. [ABSTRACT FROM AUTHOR]

This paper reports first-principles calculations on nanosheets of Ge–Sb–Te compounds, namely Sb 2 Te 3 , GeSb 2 Te 4 and Ge 2 Sb 2 Te 5 under two crystalline atomic stakings S1 and S2. Sb 2 Te 3 , GeSb 2 Te 4 and Ge 2 Sb 2 Te 5 -S1 are semiconductors with a narrow band gap ranging between 0.7 and 0.74 eV as evaluated with the HSEsol functional. The transport properties have been investigated by Boltzmann transport theory together with deformation potential theory. The strain effects on their electronic and thermoelectric properties as well as on their dynamical properties have been investigated. A valence band convergence is found in the equilibrium structures, which is an efficient approach to improve the thermoelectric performance of materials. Sb 2 Te 3 , GeSb 2 Te 4 and Ge 2 Sb 2 Te 5 -S1 possess high TE performance in a wide range of temperature, and the highest values of zT are 2.94, 2.63 and 2.27, respectively. [ABSTRACT FROM AUTHOR]

The heavily faulted Martian terrains of Ceraunius Fossae and Tractus Fossae, south of the Alba Mons volcano, have previously only been considered as parts of larger tectonic studies of Alba Mons, and consequently the complexity of the faulting remains unclear. As these terrains are in the midst of the large Tharsis volcanoes, the study of their surface deformation has the potential to help unravel the volcano‐tectonic deformation associated with the growth of Tharsis as well as to decipher details of the magma‐tectonic processes responsible for graben formation. Here, we distinguish between faults and collapse structures based on image and topographic evidence. We mapped ∼12,000 faults, which we grouped into three distinct fault groups based on orientation, morphology, and relative ages. These show a temporal evolution in the mapped fault orientations from NE to N‐S to NW with associated changes in stress orientations. We also mapped collapse features and categorized them into four different groups: pit‐crater chains, catenae, u‐shaped troughs and chasmata. Examining the four collapse structure groups reveals that they are likely four progressive stages in the erosional evolution of pit‐crater chains. Together, this revealed a structural history heavily influenced by lateral diking from both local (radial to Alba Mons, Pavonis Mons and Ascraeus Mons) and regional (radial to Tharsis) sources, and vertical diking from a proposed Ceraunius Fossae centered magma source. This, along with an updated crater size‐frequency distribution analysis of the unit ages, reveals a highly active tectonic and magmatic environment south of Alba Mons in the Middle Amazonian. Plain Language Summary: The large‐scale faults surrounding the dome of the Alba Mons volcano on Mars have been studied intensely, while the faulted area south of Alba Mons has received relatively little attention. Closer inspection of these southern terrains, namely Ceraunius Fossae and Tractus Fossae, reveals that this area is far more complex in structure and more recent in activity than previously thought. In this study, we mapped and measured all the faults in the study areas. In addition to the faults, the surface of the study area is covered in "collapse structures." These are circular to trough‐like features created when the surface material has fallen into a subsurface cavity. We mapped and characterized these faults and collapse structures, in order to determine the history of events and which geological process created them. We found three distinct extensional faulting events, and examples of four types of collapse structures. These events all took place within 2.4–1.4 billion years ago during the Amazonian period. Together, these results show that magmatic activity drove structure deformation, both from the surrounding Alba Mons, Ascraeus Mons and Pavonis Mons volcanoes, and also from a local large magmatic source situated directly underneath Ceraunius Fossae. Key Points: Three fault populations and four types of collapse features are mapped and analyzed in Ceraunius Fossae and Tractus FossaeWe present a four‐stage structural evolution of the area, with dike‐induced deformation being the prevalent processThe stages of activity in the study area all occurred during the Amazonian, with activity from a local magmatic source beneath Ceraunius Fossae [ABSTRACT FROM AUTHOR]

Understanding and predicting the charge carriers in two-dimensional materials is critical for advancements in electronic devices. Numerous research efforts focus on optimizing their functionality to unveil their full potential for expected applications. 2D materials such as graphene exhibit unique electronic, mechanical, thermodynamic and transport characteristics, making them promising candidates for nano electronic devices. Herein, we report 2D phosphorene-like (P-AsP3) and graphene-like arsenic tri phosphide (G-AsP3) monolayers. Our findings reveal that both monolayers possess semiconducting nature, where P-AsP3 exhibits a direct bandgap of 1.51 eV and is anisotropic in carrier transport, while G-AsP3 possesses an indirect bandgap of 2.62 eV and is isotropic in carrier transport. The phonon dispersion curve and molecular dynamics (MD) simulations at 500 K confirm their dynamic and thermodynamic stability. Deformation potential theory (DPT) was applied to determine the carrier mobilities of electrons and holes along the x (armchair) and y (zigzag) directions. In the armchair direction, electron mobility significantly increases from 212 cm2 V−1 s−1 in the P-AsP3 monolayer to 1412 cm2 V−1 s−1 in the G-AsP3 monolayer, and for holes, it rises from 367 cm2 V−1 s−1 to 1003 cm2 V−1 s−1, respectively. A suitable bandgap and high carrier mobility highlight their potential for nanoelectronic devices. [ABSTRACT FROM AUTHOR]

A meta-porphyritic granitoid in the Makrohar Granulite Belt, Central India contains extensive myrmekite. This work evaluates the controls of fluid in relation to deformation and the formation of myrmekite all along the periphery of an alkali-feldspar megacryst. Two different myrmekite morphologies are present: (1) vermicular intergrowth of plagioclase (An38–39) and quartz (Myr1); and (2) polygonal aggregates of coarse plagioclase (An45–46) and quartz (Myr2). Petrographic features suggest that myrmekite Myr1 nucleates on alkali-feldspar and plagioclase porphyroclasts and the myrmekite front moved into the alkali feldspar by replacing it; and that myrmekite Myr2 and the secondary biotite which replaces plagioclase porphyroclasts and garnet form together. Deformation had a decisive role in forming the polygonal aggregates of Myr2, however field and microtextural features do not support any significant control of deformation during the formation of Myr1. Reaction modelling and a mass-balance calculation suggest that Ca and Na are added to, and K is removed from, the alkali feldspar during the myrmekite formation at nearly constant Si and Al. However, the secondary biotite-forming reaction, consumes K and releases Ca. Interpretation of the reaction textures in different isothermal–isobaric sections of μK2O–μCaO in the KCFASH system suggest that CaO and K2O moved in opposite directions for myrmekitisation and along their respective chemical potential gradients created between the sites of formation of myrmekite and secondary biotite. The feedback mechanism which operated between the two reaction sites was controlled by infiltration of brine-rich fluid in the meta-granitoid during a regional hydration event (550–600oC and 5–6 kbar). Volume reduction of ~10% during the formation Myr1 and Myr2 drew the brine-rich fluid towards the alkali feldspar and thus facilitated the process of myrmekite formation. Variation in the morphology of quartz in the myrmekite is attributed to the cooling of the complex. [ABSTRACT FROM AUTHOR]

The periodic storage and release of water in reservoirs have the potential to accelerate deformation or trigger ancient landslides. Interferometric synthetic aperture radar (InSAR) technology, renowned for its wide coverage and high precision, has emerged as an effective technique for the identification and monitoring of landslides. This study utilized spaceborne InSAR technology to identify and interpret landslides in the Liujiangxia reservoir area in China, leading to the detection of a total of 20 landslides. Moreover, among these 20 landslides, the landslide with substantial deformation (LJX02) was chosen, and the wavelet quantitative analysis technique was employed to investigate the correlation and time lag between various elevation positions of this landslide, the reservoir water level, and rainfall. The study successfully demonstrated that the deformation of the landslide lagged behind the reservoir water level by 152.10-182.50 days (from low to high elevation) and was delayed by 45.60-68.44 days compared to rainfall (from high to low elevation). [ABSTRACT FROM AUTHOR]

Since the implementation of the Materials Genome Project by the Obama administration in the United States, the development of various computational materials' databases has fundamentally expanded the choice of industries such as materials and energy. In the field of thermoelectric materials, the thermoelectric figure of merit (ZT) quantifies the performance of the material. From the viewpoint of calculations for vast materials, the ZT values are not easily obtained due to their computational complexity. Here, we show how to build a database of thermoelectric materials based on first-principle calculations for the electronic and heat transport of materials. Firstly, the initial structures are classified according to the values of bandgap and other basic properties using the clustering algorithm K-means in machine learning, and high-throughput first principle calculations are carried out for narrow-bandgap semiconductors which exhibit a potential thermoelectric application. The present framework of calculations mainly includes a deformation potential module, an electrical transport performance module, a mechanical and a thermodynamic properties module. We have also set up a search webpage for the calculated database of thermoelectric materials, providing search facilities and the ability to view the related physical properties of materials. Our work may inspire the construction of more computational databases of first-principle thermoelectric materials and accelerate research progress in the field of thermoelectrics. [ABSTRACT FROM AUTHOR]

The highly strained, phenylene‐derived organic cages are typically regarded as very rigid entities, yet their deformation potential and supramolecular properties remain underexplored. Herein, we report a pliable conjugated phenylene nanocage by synergistically merging rigid and flexible building blocks. The anisotropic cage molecule contains branched phenylene chains capped by a calix[6]arene moiety, the delicate conformational changes of which endow the cage with a remarkably deformable cavity. When complexing with fullerene guests, the cage showcases excellent guest‐adaptivity, with its cavity volume capable of swelling by as much as 85 %. [ABSTRACT FROM AUTHOR]

Random polypropylene is considered an alternative material to regular polypropylene for applications where improved impact and creep resistance, as well as stiffness, are required. Random polypropylene nanocomposites reinforced with dimethyldichlorosilane-treated silica particles were prepared using meltmixing. The effect of varying the nanoparticles' content on the structural, mechanical, damping and thermal behavior of the nanocomposites was investigated. The results indicated the improved deformation potential, fracture toughness, and energy storage capacity of the matrix with increasing the filler content. It was observed that the use of high filler fractions limited the reinforcing efficiency of the SiO2 nanoparticles due to the formation of large agglomerates. The nanoparticles' segregation was initially advised by modeling Young's modulus but was also confirmed by electron imaging. Examination of the thermal properties of the nanocomposites indicated the limited effect of the nanoparticles on the melting behavior along with the thermal stability of the matrix. These results confirmed the usage of silica nanoparticles as a way of further improving the mechanical and thermomechanical properties of random polypropylene. [ABSTRACT FROM AUTHOR]

Negative Poisson's ratio (NPR) metamaterials are attractive for their unique mechanical behaviors and potential applications in deformation control and energy absorption. However, when subjected to significant stretching, NPR metamaterials designed under small strain assumption may experience a rapid degradation in NPR performance. To address this issue, this study aims to design metamaterials maintaining a targeted NPR under large deformation by taking advantage of the geometry nonlinearity mechanism. A representative periodic unit cell is modeled considering geometry nonlinearity, and its topology is designed using a gradient-free method. The unit cell microstructural topologies are described with the material-field series-expansion (MFSE) method. The MFSE method assumes spatial correlation of the material distribution, which greatly reduces the number of required design variables. To conveniently design metamaterials with desired NPR under large deformation, we propose a two-stage gradient-free metamaterial topology optimization method, which fully takes advantage of the dimension reduction benefits of the MFSE method and the Kriging surrogate model technique. Initially, we use homogenization to find a preliminary NPR design under a small deformation assumption. In the second stage, we begin with this preliminary design and minimize deviations in NPR from a targeted value under large deformation. Using this strategy and solution technique, we successfully obtain a group of NPR metamaterials that can sustain different desired NPRs in the range of [-0.8, -0.1] under uniaxial stretching up to 20% strain. Furthermore, typical microstructure designs are fabricated and tested through experiments. The experimental results show good consistency with our numerical results, demonstrating the effectiveness of the present gradient-free NPR metamaterial design strategy. [ABSTRACT FROM AUTHOR]

Using first-principles density functional theory based approach, we investigate the tunability of the thermoelectric properties of perovskite MgSiO3. We find that the thermoelectric properties are strongly correlated with the electronic structure and can, therefore, be modulated with uni-axial tensile and compressive strains. Key thermoelectric parameters, such as the Seebeck coefficient (S), show non-monotonic behavior, displaying large shifts with the application of 1 % uni-axial tensile strain. The relevance of this small strain value also appears in structural distortion of the oxygen octahedra and band convergence in the electronic band structure. The band structure modifications also introduce a strong strain dependence of the relaxation time, as defined within the deformation potential approach. As a result, an improvement of up to 35 % is observed in zT with the application of 1 % tensile strain. Our results highlight a possible new route to improving thermoelectric performance in perovskite oxide thermoelectrics. [ABSTRACT FROM AUTHOR]

The properties of most III–V semiconductor materials in the wurtzite structure are not known because of their metastable character. However, recent advances in the growth of III–V wurtzite nanorods open new perspectives for applications. In this work, we present a systematic computational study of bulk wurtzite III–V semiconductors, using predictive ab initio methods, to provide a necessary base knowledge for studying the nanostructures. The most important physical properties of bulk systems, i.e., lattice constants, elasticity, spontaneous polarization, piezoelectricity, band structures, deformation potentials, and band offsets, have been studied. Comparison with the available experimental and theoretical data shows the high credibility of our results. Moreover, we provide a complete set of parameters for a six-band k ⋅ p model, which is widely used for simulating devices based on semiconductor heterostructures. [ABSTRACT FROM AUTHOR]

This article aims to study the shock resistance capability of multi-element alloys. In this study, we utilized nonequilibrium molecular dynamics-based simulations with an embedded atom method potential to predict the deformation governing mechanism in a multi-elemental alloy system subjected to shock loading. The evolution of shock front width, longitudinal stress, shear stress, and dislocation density were investigated for different polycrystalline multi-element systems containing different mean grain sizes of 5, 10, and 18 nm, respectively. In order to quantify the effect of lattice distortion, average atom (A-atom) potential for quinary (high entropy) and ternary (medium entropy) configurations was also developed in this work. The random composition of multi-element alloys was replaced with single atom-based A-atom arrangements to study the effect of lattice distortion on shock resistance capabilities of high entropy alloy and medium entropy alloy. It was predicted from simulations that a higher value of lattice distortion component in the CoCrCuFeNi alloy leads to provide superior resistance against shock wave propagation as compared to the ternary alloy CrFeNi. In nanocrystalline configurations, dislocations, and stacking faults, only dislocations governed the deformation mechanics in monocrystalline configurations. The simulations indicate that grain size significantly affects the rates of generation of secondary/partial dislocations, hence affecting the stresses and the deformation mechanism of the structures. [ABSTRACT FROM AUTHOR]

In the laser powder bed fusion (LPBF) process, fast solidification of molten powders and significant temperature gradients generate substantial residual stresses in the build part. The induced residual stresses can result in excessive deformation and potential crack initiation and propagation. Development of a predictive reliable model is thus of paramount importance to predict the induced residual stresses in LPBF process without cost and complexities associated with experimental tests. High-fidelity thermo-mechanical models to predict the residual stresses and distortion in the macro-scale are generally impractical owing to their high level of computational time. Recently, the modified inherent strain methodology has proven to be a viable alternative for predicting residual stresses and distortions efficiently. In this study, a multi-scale finite element-based model of the LPBF process for Inconel-718 is developed utilizing modified inherent strain method to estimate the accumulated stress in the process. The stress formation and inherent strain values were evaluated in a micro-scale deposition considering the effect of LPBF process parameters using Abaqus/standard. The material constitutive models, including kinematic hardening, elastic-perfectly plastic, isotropic hardening, and Johnson–Cook model, and their effect on the evolution of plastic strain were investigated. The precision of the prediction was examined based on the quantity of equivalent layers, employing the agglomeration approach in part-scale analysis and subsequently confirmed experimentally through the fabrication of a printed cantilever beam. The proposed framework showed that the kinematic hardening model performed better than other material models, with an error of less than 6% when compared to experimental measurements. Moreover, the study highlights the significance of selecting the most appropriate material model for future studies involving the integration of advanced artificial neural networks and process parameter optimization to achieve precise and computationally efficient predictions. [ABSTRACT FROM AUTHOR]

The paper reveals some remarkable form-invariance features of the 'Jacobi-reference' canonical Sturm–Liouville equation (CSLE) in the particular case of the density function with the simple pole at the origin. It is proven that the CSLE under consideration preserves its form under the two second-order Darboux–Crum transformations (DCTs) with the seed functions represented by specially chosen pairs of 'basic' quasi-rational solutions (q-RSs), i.e., such that their analytical continuations do not have zeros in the complex plane. It is proven that both transformations generally either increase or decrease by 2 the exponent difference (ExpDiff) for the mentioned pole while keeping two other parameters unchanged. The change is more complicated in the latter case if the ExpDiff for the pole of the original CSLE at the origin is smaller than 2. It was observed that the DCTs in question do not preserve bound energy levels according to the conventional supersymmetry (SUSY) rules. To understand this anomaly, we split the DCT in question into the two sequential Darboux deformations of the Liouville potentials associated with the CSLEs of our interest. We found that the first Darboux transformation turns the initial CSLE into the Heun equation written in the canonical form while the second transformation brings us back to the canonical form of the hypergeometric equation. It is shown that the first of these transformations necessarily places the mentioned ExpDiff into the limit-circle (LC) range and then the second transformation keeps the pole within the LC region, violating the conventional prescriptions of SUSY quantum mechanics. [ABSTRACT FROM AUTHOR]

Application of displacement based seismic design in light‐frame timber construction This contribution deals with a displacement based seismic design procedure in timber construction. After a short explanation of the calculation methods regulated by standards, two different models are described with which the non‐linear behaviour of bracing elements in timber construction can be predicted to be included in a displacement based seismic design. In addition to the proposal in the current draft of Eurocode 8, an own approach is presented. The models are compared for different configurations of light frame timber shear walls and the differences are shown. Subsequently, displacement based seismic design is carried out on a two‐storey and a four‐storey reference building, taking into account different design configurations of the bracing system. It can be shown that a displacement based seismic design behaves very robustly in relation to changes of the input parameters and that there is a high potential to quantify hidden potentials in terms of deformation capacity in a structure. [ABSTRACT FROM AUTHOR]

Deformation monitoring plays a pivotal role in assessing dam safety. Interferometric Synthetic Aperture Radar (InSAR) has the advantage of obtaining an extensive range of deformation, regardless of weather conditions. The Datengxia Water Conservancy Hub is the largest in-construction dam in China. To effectively assess the in-construction dam safety, the SBAS-InSAR (Small Baseline Subset-InSAR) technique and 86 Sentinel-1 images (from 11 February 2020, to 16 January 2023) have been employed in this study to monitor the deformation over the reservoir and its surrounding areas. The reliability of the SBAS-InSAR monitoring results over the study area was demonstrated by the in situ monitoring results. And the InSAR results show that the central section of the left dam exhibits the most substantial cumulative deformation, attributed to the maximal water pressure. This is closely followed by the left end of the dam, which reflects a similar but smaller deformation. However, the in-construction cofferdam facilities make the right-end section of the left dam more robust, and the deformation is the most stable. Additionally, significant deformation of the auxiliary dam slope has been identified. Moreover, the analysis indicated that the deformation of the four upstream slopes is closely related to the precipitation, which potentially poses a threat to the safety of the Datengxia Dam. [ABSTRACT FROM AUTHOR]

Strain engineering has been extensively explored to modulate the various intrinsic properties of flexible inorganic semiconductor films. However, experimental characterization of tensile and compressive strain-induced modulation of optoelectronic properties and their differences has not been easily implemented in flexible inorganic semiconductor films. Herein, the strain-dependent structural, optical, and optoelectronic properties of flexible ZnO films under pre-tensile and pre-compressive strains are systemically investigated by a Mueller matrix ellipsometry-based quantitative characterization method combined with x-ray diffraction and first-principle calculation. With extended prestress-driven deposition processing under bi-direction bending modes, pre-tensile and pre-compressive strains with symmetric magnitudes can be achieved in flexible ZnO films, which allows precise observation of the strain-driven asymmetric modulation of optoelectronic properties. When the applied prestrain varies approximately equally from 0% (baseline) to −0.99% (compression) and 1.07% (tensility), respectively, the relative changes for the c-axis lattice constant are 0.0133 and 0.0104 Å, respectively. Meanwhile, the dependence factors of the bandgap energy on the pre-compression and pre-tensile strains were determined as −0.0099 and −0.0156 eV/%, respectively, and the complex refractive index also presents an asymmetric varying trend. With the help of the strain–stress analysis and the first-principle calculation, the intriguing asymmetric strain-optical modulation effect could be attributed to the biaxial strain mechanism and the difference in the deformation potential between the two prestrain modes. These systematic investigation consequences are thus promising as a basis for the booming applications of the flexible inorganic semiconductor ensemble. [ABSTRACT FROM AUTHOR]

The anti-dip bedding rock slopes have threatened global infrastructure construction and urban expansion seriously. Taking the Guang'an Village rockslide as an example, this paper firstly studied the deformation characteristics of the rockslide with anti-dip bedding structure based on in-situ investigation and monitoring, and then the relevant influencing factors were summarized. On this basis, a new evolution model of continuous-pushing-section pressing locked-section and the instability mechanism of the rock slope were proposed. Finally, the applicability of the model and the deformation tendency of the rock slope were further discussed. A catastrophic sliding event has once occurred in the Guang'an Village rockslide in 2017, after which the deformation of the potential source area III (PSA-III) was accelerating. The presence of the sliding-prone geological structure provides the basic conditions for the deformation of the rock slope and the development of the sliding zone. Rainfall is the major external trigger that promotes the deformation. As the sliding zone extends forward, the overlying deformation body will keep on pushing against the preceding rock mass, which will contribute to the forward extension of the sliding zone as well. When the final locked section is crushed, the rock slope will lose balance. According to the observation in the field, the PSA-III is in the late stage of the deformation-increasing phase currently. This study can provide a reference for the analysis of failure mechanism and the design of monitoring and mitigation of other large anti-dip bedding rock slides. [ABSTRACT FROM AUTHOR]