Miracle-dz/UniFAR-FTUs huggingface dataset:
Investigation of ferroelectric materials by the thermal noise method: Advantages and limitations

ABSTRACT An overview of the dielectric properties of ferroelectrics by means of thermal noise method from 60s to our days is presented. Different realizations of the thermal noise method are discussed and the advantages and disadvantages are compared for bulk crystals and for thin films. A short overview of the application of the thermal noise method for measurements of dielectric properties of different objects (barium titanate and triglycine sulphate crystals and barium titanate thin films) is presented. The original method for thermal noise voltage characterization, based on digital data processing is demonstrated. The piezoactivity data for barium titanate crystals below phase transition temperature are obtained by thermal noise method. Barkhausen thermal noise data for barium titanate and triglycine sulphate crystals are analyzed below and above the phase transition temperature. The possibility of equivalent circuit analysis for thin ferroelectric films using their noise characteristics is discussed.
On regularized estimation methods for precision and covariance matrix and statistical network inference

Estimation of the covariance matrix is an important problem in statistics in general because the covariance matrix is an essential part of principal component analysis, statistical pattern recognition, multivariate regression and network exploration, just to mention but a few applications. Penalized likelihood methods are used when standard estimates cannot be computed. This is a common case when the number of explanatory variables is much larger compared to the sample size (high-dimensional case). An alternative ridge-type estimator for the precision matrix estimation is introduced in Article I. This estimate is derived using a penalized likelihood estimation method. Undirected networks, which are connected to penalized covariance and precision matrix estimation and some applications related to networks are also explored in this dissertation. In Article II novel statistical methods are used to infer population networks from discrete measurements of genetic data. More precisely, Least Absolute Shrinkage and Selection Operator, LASSO for short, is applied in neighborhood selection. This inferred network is used for more detailed inference of population structures. We illustrate how community detection can be a promising tool in population structure and admixture exploration of genetic data. In addition, in Article IV it is shown how the precision matrix estimator introduced in Article I can be used in graphical model selection via a multiple hypothesis testing procedure. Article III in this dissertation contains a review of current tools for practical graphical model selection and precision/covariance matrix estimation. The other three publications have detailed descriptions of the fundamental computational and mathematical results which create a basis for the methods presented in these articles. Each publication contains a collection of practical research questions where the novel methods can be applied. We hope that these applications will help readers to better understand the possible applications of the methods presented in this dissertation.
Complementary Disentangling and Dynamic Graph Convolution for Skeleton Based Action Recognition

In this study, we introduce a novel skeleton-based action recognition approach, the Complementary Disentangling and Dynamic Graph Convolution Network (CDD-GCN). This method combines multi-scale graph convolution and multi-head self-attention to model human body structure and motion characteristics. We employ a complementary disentangle neighbor-hoods method to generate multi-scale graphs, which eliminates the redundant dependency on nearby nodes when receiving information from distant nodes while maximally preserving the structural features of the human skeleton. In accordance with the characteristics of human skeletal sequences, we improve the self-attention mechanism by introducing temporal pooling, semantic information, graph importance tuning matrix, and high-probability graph dropout into the dynamic graph generation process, achieving more effective action connections with lower computational complexity. We integrate the self-attention mechanism with the graph convolution process at the feature level, enabling independent learning and better performance of both, and modify the multi-head feature aggregation method of self-attention to be consistent with the graph convolution process, facilitating smoother subsequent fusion. Experimental results demonstrate that the CDD-GCN achieves the state-of-the-art performance on two large-scale datasets, NTU RGB+D 60 and 120, exemplified by a 92.7% accuracy on the cross-subject benchmark of NTU RGB+D 60, while maintaining low computational costs.
Etching Kinetics of (100) Single Crystal Diamond Surfaces in a Hydrogen Microwave Plasma, Studied with In Situ Low‐Coherence Interferometry

A low‐coherence interferometry (LCI) was used to measure in situ the etch rate (ER) of synthetic single crystal (SC) diamonds in H2 microwave plasma, at substrate temperatures in the broad range of 800–1370 °C. The method allows the collection of the kinetic data on a single sample without switching off the plasma. (100)‐orientated SC plates of CVD and IIa type HPHT diamond were systematically etched in pure hydrogen at pressure p = 130 Torr and microwave power density of ≈300 W cm−3. The activation energies Ea of 42 ± 5 and 32 ± 4 kCal mol−1 have been determined for the CVD and HPHT substrates. An enhanced etching rate of a subsurface defected layer with thickness of ∼1 μm or less, formed upon polishing of the samples, is revealed. Surface morphology, roughness, and the shape of etch pits produced by a selective etching of defects, were characterized with optical profilometry. CH and dimer C2 radicals were detected in the H2 plasma with optical emission spectroscopy, as a result of the diamond etching, and the emission intensity of these species was linked to the substrate etch rate.
Passenger Flow Prediction of Tianjin Metro Line 3 under Time Series Clustering

Taking Tianjin Metro Line 3 as an example, this study mainly explored the influence of forecasting methods on the accuracy of short-term passenger flow forecasting for rail transit. Based on the station's inbound and outbound passenger flow attributes, the time sequence clustering method was applied to classify urban rail transit stations into four categories, and extreme gradient boosting (XG Boost), back propagation (BP) and autoregressive moving average (ARMA) models were used to predict the short-term passenger flow of each type of stations, and the results were compared. The results show that the methods with the highest accuracy in predicting the passenger flow of the four types of stations are XG Boost, ARMA, ARMA and BP, and XG Boost shows a greater advantage in prediction time.
Influence of loading history on the response of a reinforced concrete beam

An investigation considering the influence of loading histories on the performance of a reinforced concrete beam plastic hinge is described. Twelve loading histories were considered, including conventional procedures employed in the United States, Japan and New Zealand, and artificially generated histories derived from recorded earthquake ground motions. Details of the prototype structure and the test beam are described, followed by comprehensive reporting of experimental data. Performance descriptors and further treatment of the experimental data are presented in a companion paper.
Signature change in loop quantum gravity: General midisuperspace models and dilaton gravity

Models of loop quantum gravity based on real connections have a deformed notion of general covariance, which leads to the phenomenon of signature change. This result is confirmed here in a general analysis of all midisuperspace models without local degrees of freedom. As a subclass of models, 2-dimensional theories of dilaton gravity appear, but a larger set of examples is possible based only on the condition of anomaly freedom. While the classical dilaton gravity models are the only such systems without deformed covariance, they do give rise to signature change when holonomy modifications are included.
Gamma Radiolysis of Phenyl-Substituted TODGAs: Part I

ABSTRACT The radiolytic stabilities of three phenylated analogs of N,N,N’,N’-tetraoctyl diglycolamide (TODGA) were investigated: 2-(2-(di-n-octylamino)-2-oxoethoxy)-N,N-di-n-octyl-2-phenylacetamide (PhTODGA), which has a phenyl substituent bound to a central methylene, 2-(2-(di-n-octylamino)-2-oxo-1-phenylethoxy)-N,N-di-n-octylpropanamide (PhMeTODGA), which also contains a methyl substituent bound to the methylene on the other side of the ether moiety, and, 2-(2-N-n-hexyl-N-phenylamino)-2-oxoethoxy)-N-n-hexyl-N-phenylacetamide (DHDPDGA), which has phenyl substituents located on the amide groups instead of the central methylenes. The objective of Part I of this series of papers covers was to evaluate the contribution of the phenyl group to the radiolytic stability of these diglycolamides when irradiated in a) n-dodecane, and b) n-dodecane in the presence of a nitric acid-containing aqueous phase. The results indicate that the presence of the phenyl group decreases the overall radiolytic stability compared to unsubstituted TODGA. However, the results also indicate that the phenyl groups interact with nitric acid in a cooperative fashion that enhances the radiation stability of the phenylated diglycolamide (DGA) derivatives in the presence of a nitric acid-containing aqueous phase compared to irradiation in only n-dodecane. The results are consistent with the hypothesized formation of nitric acid-phenylated DGA complexes in the n-dodecane phase that are significantly more stable with respect to gamma irradiation, compared to the phenylated DGA molecules alone.
Event-triggered and self-triggered control for linear systems with actuator saturation

In this paper, both event-triggered and self-triggered transmission strategies are proposed for dynamical systems subject to actuator saturation. The designed triggering condition, which is expected to save more network resources, is closely related to the cases where either the actuator saturates or it does not. The linear quadratic optimal control method is utilized to guarantee the asymptotic stability of the closed-loop systems. Global and local stability results are considered, respectively. For local stability, two sufficient conditions are presented to derive the asymptotic stability region. The minimum inter-transmission time of the proposed triggering mechanism is explicitly formulated to eliminate the Zeno behaviour. Finally, an example is provided to demonstrate the effectiveness of the theoretical results.
Black Hole Mass Decreasing, The Power and The Time of Two Black Holes in Coalescence, in The Quintessence Field

In this paper, we investigate some consequences of the black hole stabilization of Schwarzschild in the presence of quintessence type of dark energy which leads the way to the black hole mass decreasing other than the Hawking radiation process. The results show that in the quintessence field, the black hole shows a second-order phase transition, implying the existence of a stable phase. However, this stabilization implies some paradoxical effects on the black hole, which gives us a new regard about black holes, precisely we obtain the negative absolute temperature and we propose a process permitting us to appreciate well the likely cause of this phenomenon. These results allow us to give a new definition of the surface gravity for the Schwarzschild black hole in the field of quintessence, which depends on the flux of dilatation produced by the quintessence type of dark energy. Afterward, we analyze the impact of dark energy on the power and the time of two black holes needed to coalesce. Keywords: Quintessence, black hole, second-order phase transition, negative absolute temperature, gravitational waves
Effects of wing shape, aspect ratio and deviation angle on aerodynamic performance of flapping wings in hover

This numerical study is focused on assessing the effect on the aerodynamic hovering performance of wing shapes defined by the radius of the first moment of the wing area ( r 1 ¯ ) and aspect ratio (AR). In addition, the effect of introducing a deviation angle in the kinematics is examined. The performance of r 1 ¯ = 0 . 43 , 0.53, and 0.63 wings with AR of 1.5, 2.96, 4.5, and 6.0 is investigated at Reynolds numbers (Re) = 12, 400, and 13 500. The performance trends of the wing shapes have been observed to be independent of Re for both 2-angle and 3-angle kinematics. This is because high suction pressures associated with the leading-edge vortex are predominantly spread in the distal (away from the wing root) and leeward regions (towards the trailing-edge) of high flapping velocities for all the cases. While the deviation angle is detrimental to the production of lift and power economy (PE, defined as the ratio of the mean lift coefficient to the mean aerodynamic power coefficient) at Re = 12 due to strong .
The Influence of Weather Patterns and the Madden‐Julian Oscillation on Extreme Precipitation Over Sri Lanka

Sri Lanka is affected by extreme precipitation events every year, which cause floods, landslides and tremendous economic losses. We use the ERA5 reanalysis data set to understand the association of extreme precipitation events with 30 weather patterns, which were originally derived to represent the variability of the Indian climate during January–December 1979–2016. We find that weather patterns that are most common during the northeast monsoon (December–February) and second intermonsoon (October–November) seasons produce the highest number of extreme precipitation events. Furthermore, extreme precipitation events occurring during these two seasons are more persistent than those during the southwest monsoon (May–September) and first intermonsoon (March–April) seasons. We analyze the modulation of extreme precipitation events by the Madden‐Julian Oscillation, and find that their frequency is enhanced (suppressed) in phases 1–4 (5–8) for most weather patterns.
Thermodynamic and Elastic Properties of Interstitial Alloy FeC with BCC Structure at Zero Pressure

The analytic expressions for the thermodynamic and elastic quantities such as the mean nearest neighbor distance, the free energy, the isothermal compressibility, the thermal expansion coefficient, the heat capacities at constant volume and at constant pressure, the Young modulus, the bulk modulus, the rigidity modulus, and the elastic constants of binary interstitial alloy with body-centered cubic (BCC) structure, and the small concentration of interstitial atoms (below 5%) are derived by the statistical moment method. The theoretical results are applied to interstitial alloy FeC in the interval of temperature from 100 to 1000 K and in the interval of interstitial atom concentration from 0 to 5%. In special cases, we obtain the thermodynamic quantities of main metal Fe with BCC structure. Our calculated results for some thermodynamic and elastic quantities of main metal Fe and alloy FeC are compared with experiments.
Turbulence Models for Predicting Wall Shear Flows with Heat Transfer in Engineering Applications

iii Abstract In order to apply the low-Reynolds-number two-equation heat-transfer models to an engineering calculation of turbulent heat and mass transfer and fluid flows, several turbulence models are improved. First, the modified low-Reynolds-number (LRN) k–ε model is proposed for applying a turbulent boundary layer flow with pressure gradient. In particular, the turbulent boundary layer flow with adverse pressure gradient (APG) does not maintain the standard log-law profile, i.e., Ū = 2.44 ln y + 5.0, in which the mean more rapidly reaches the log-law region than a zeropressure gradient (ZPG) flow. Since almost all low-Reynolds-number k–ε models adopt the nondimensional distance y in the wall-reflection function, these models must give the velocity profile along the standard log-law. The proposed model includes the nondimensional pressuregradient parameter P in the wall-reflection function. Therefore, the proposed model improves the prediction of turbulent quantities in the APG flow. The model adopts the quasi-dissipation rate, ε̃, for the calculation stability, the so-called k–ε̃ model. Though the ε̃-equation, whose boundary condition can be put at 0 at the wall is employed in the model, the turbulent Reynolds number is defined using the net ε. Therefore, the wall-limiting behaviour of the Reynolds shear stress is satisfied exactly like the k–ε model. Second, to analyze turbulent heat transfer with various thermal boundary conditions, the LRN two-equation heat transfer model is improved. The quasi-dissipation rate of the temperature variance, ε̃θ, is adopted to the model for calculation stability. The proposed LRN twoequation heat transfer model is used together with the LRN linear k–ε̃ or LRN nonlinear k–ε̃ model for the calculation, and satisfies exactly the wall-limiting behaviour of turbulent heat-flux in the cases of both existing and non-existing temperature fluctuation at the wall. Agreement with the experimental and the direct numerical simulation (DNS) data is quite satisfactory. Next, the transport equation for the dissipation rate of the temperature variance, εθ, is modeled rigorously (term to term) using the trustworthy DNS database. The DNS database gives some turbulent quantities in detail, in which the budget of εθ is contained. In the modelling, the terms of εθ-equation are modeled in correspondence with the rigorous terms. The turbulent diffusion terms are especially modeled with the conventional gradient diffusion-type model and new large-scale motion model. Thus, the predicted budgets of εθ-equation are in good agreement with the DNS data. Since the εθ-equation is modified rigorously, the modeled equation
Statistical inference for heteroscedastic semi-varying coefficient EV models under restricted condition

This paper studies the estimation and testing problems for a class of heteroscedastic semi-varying coefficient errors-in-variables models under additional restricted condition. Initial restricted estimates for the regression coefficients and varying coefficients are first constructed based on the profile least squares procedure without considering the heteroscedasticity, then a bias-corrected kernel type restricted estimate for the variance function is proposed, which in turn is used to construct re-weighted bias-corrected restricted estimates of the regression coefficients and the varying coefficients. The large sample properties including the consistency and asymptotic normality are thoroughly investigated. To test hypotheses on the parametric component, we propose a test statistic based on the profile Lagrange multiplier, and show that its asymptotic null distribution is standard chi-squared distribution. Some simulation studies are conducted to evaluate the finite sample performance of the proposed methods.
NITROGEN ISOTOPIC RATIO OF COMETARY AMMONIA FROM HIGH-RESOLUTION OPTICAL SPECTROSCOPIC OBSERVATIONS OF C/2014 Q2 (LOVEJOY)

The icy materials present in comets provide clues to the origin and evolution of our solar system and planetary systems. High-resolution optical spectroscopic observations of comet C/2014 Q2 (Lovejoy) were performed on 2015 January 11 (at 1.321 au pre-perihelion) with the High Dispersion Spectrograph mounted on the Subaru Telescope on Maunakea, Hawaii. We derive the 14N/15N ratio of NH2 (126 ± 25), as well as the ortho-to-para abundance ratios (OPRs) of the H2O+ ion (2.77 ± 0.24) and NH2 (3.38 ± 0.07), which correspond to nuclear spin temperatures of >24 K (3σ lower limit) and 27 ± 2 K, respectively. We also derive the intensity ratio of the green-to-red doublet of forbidden oxygen lines (0.107 ± 0.007). The ammonia in the comet must have formed under low-temperature conditions at ∼10 K or less to reproduce the observed 14N/15N ratio in this molecule if it is assumed that the 15N-fractionation of ammonia occurred via ion–molecule chemical reactions. However, this temperature is inconsistent with the nuclear spin temperatures of water and ammonia estimated from the OPRs. The interpretation of the nuclear spin temperature as the temperature at molecular formation may therefore be incorrect. An isotope-selective photodissociation of molecular nitrogen by protosolar ultraviolet radiation might play an important role in the 15N-fractionation observed in cometary volatiles.
Extreme Precipitation‐Temperature Scaling in California: The Role of Atmospheric Rivers

The sensitivity of atmospheric river (AR)‐induced precipitation to climate change is primarily driven by increases in atmospheric water vapor with warming. However, the rate at which AR‐based precipitation intensifies with warming and whether this rate differs from non‐AR events remains uncertain. This work uses multiple statistical models to estimate regional, extreme precipitation‐temperature scaling rates in California for AR and non‐AR events. Scaling rates are determined using cold‐season daily and hourly precipitation, along with multiple temperature variables to assess robustness of the results. We find that regional scaling rates for ARs are consistently larger than non‐ARs, especially for hourly event maxima (posterior median scale rates of 5.7% and 2.4% per °C for ARs and non‐ARs, respectively). ARs remain near saturated (i.e., high relative humidity) and exhibit more lift and a stronger increase in specific humidity aloft with warming as compared to non‐ARs, helping to explain the difference in precipitation‐temperature scaling rates.
The Design of Quasi-Optimal Higher Order Sliding Mode Control via Disturbance Observer and Switching-Gain Adaptation

In this paper, a quasi-optimal higher order sliding mode control (HOSMC) scheme is designed using disturbance observer (DOB) and adaptive techniques. The overall HOSMC scheme is constituted by three portions: 1) a switch-based quasi-optimal control law that ensures rapid finite-time stabilization of the origin, producing a nominally uncertainty-free system, based on a perturbed chain of integrators; 2) a DOB which estimates the lumped uncertainties with lower frequencies; and 3) an adaptive controller designed to deal with the fast-varying terms of these lumped uncertainties over the pass-band of the DOB. Since the adaptive controller and the DOB work in a cooperative manner, the only requirement is that the switching gain be greater than the bound of the DOB estimation error, instead of the bound of the lumped uncertainties. As a consequence, overestimation in the adaptive controller can be avoided by resorting to the equivalent control. Simulation results confirm the capabilities of the proposed control strategy.
Vibrational IR Spectra of Solid Carbon Monoxide

The vibrational energy levels of solid carbon monoxide are calculated, by considering a local Hamiltonian with the Morse potential with the use of the U(2) algebra. Each bond of the molecule is changed by a corresponding Lie algebra, and, finally, the local Hamiltonian is constructed with the help of interacting Casimir and Majorana operators. Only the fundamental infrared stretching modes of vibration of solid carbon monoxide are then calculated, by using that Hamiltonian, and are compared with the experimental results.