Large Square Research Articles

Wannier topology and quadrupole moments for a generalized Benalcazar-Bernevig-Hughes model

We analyze a special separable and chiral-symmetric model with a quantized quadrupole moment, extending the Benalcazar-Bernevig-Hughes model [Science 357, 61 (2017)]. Using nested-Wilson loop formalism, we give an exact expression for Wannier centers, sector polarizations, and quadrupole moments. These are connected to the winding numbers of the constitutive one-dimensional chains. We prove that these winding numbers can characterize the model's Wannier topology as a $\mathbb{Z}\times\mathbb{Z}$ set. These results clearly show that the quantization of the quadrupole moment can arise without additional spatial symmetry (except for translation symmetry) for the bulk. By switching from the Wannier representation to the Bloch representation, we derive an alternative expression for the bulk quadrupole moment and obtain its exact value. Combining the bulk quadrupole and edge polarizations, we analytically calculate the corner charge in a large square system and make the bulk-boundary correspondence explicit in an edge-consistent gauge. Our work reveals the relationship between zero-energy states at the boundary, charge localization, and the bulk quadrupole of the extended model.

Experimental assessment on the size effects of square concrete-filled steel tubular columns under axial compression

In this study, eight specimens with the sectional widths (B) of 200–1000 mm and the width-to-steel tube thickness ratios (B/t) of 40 and 50 were tested to failure under axial compression to investigate the size effects of square concrete-filled steel tubular (CFST) short columns, specifically those on the failure mode, composite elastic modulus, peak axial strain, peak axial stress, ductility index, strength index, and stress development. The test results indicate that the peak axial stress, ductility index, and strength index decrease with the increasing specimen size, while the failure mode and composite elastic modulus maintain relatively steady. Under the peak axial load, the longitudinal to yield stress ratio of steel tubes increases with the increasing specimen size, while the trend of transverse to yield stress ratio is opposite. The size effect on the transverse stress in the steel tube reduces the tube confinement effect, thus degrades the compressive strength of the core concrete. Compared to the test results, both the EC4 and the GB50936 codes are unconservative in predicting the strength of large square CFST columns. Therefore, a model considering the ratio of width to thickness (B/t) and specimen size is proposed to evaluate the axial bearing capacity of square CFST short columns.

The location of benzothiazole on the skeleton of rofecoxib defines an AIEgen and its potential application as multifunctional materials

Aggregation-induced emission (AIE) fluorescent molecules with unique photoelectric properties have received extensive attention due to the wide range of applications. In this study, a novel benzothiazole-rofecoxib-based luminogen, o-RBZ, was constructed by integrating the benzothiazole unit into the rofecoxib scaffold. It showed an obvious AIE property, which was investigated and elucidated clearly by systematic experimental and theoretical research. According to single-crystal X-ray and Hirshfeld surface analysis, the highly twisted structure of o-RBZ and restricted-stacking may allow for bright emission in the solid state. Meanwhile, the theoretical calculation revealed that small oscillator strengths (f = 0.06) and a large root mean square deviation (RMSD) were mainly responsible for the large non-radiative transition rate and the suppression of luminous efficacy in DMSO. Furthermore, o-RBZ displayed apparent solvatochromism, mechanochromism, and lipid droplets-specific imaging properties (Pearson's correlative coefficient value of 0.94, low cell cytotoxicity). These findings suggest that AIE-active o-RBZ has the potential to be developed as a multi-functional material for mechanical-force sensors and lipid droplets imaging probes.

Experimental study on the effect of ambient temperature and discharge rate on the temperature field of prismatic batteries

Lithium-ion battery surface temperature is too high or too low and poor uniformity, not only affects the performance of the battery but is also prone to thermal runaway due to local overheating of the battery. In this work, by changing the discharge rate (0.5 C, 1 C, 1.5 C, and 2 C) and the ambient temperature (−20 °C, −10 °C, 0 °C, 15 °C, 25 °C, and 35 °C), the temperature change and distribution of large capacity and large size square lithium-ion power batteries under different experimental conditions were studied. The results show that the change in battery temperature is divided into three phases. I slow rise period, II fallback period, and III rapid rise period, and with the increase of discharge rate and the decrease of ambient temperature II stage will disappear, the battery temperature change gradually shows a linear increase. As the discharge rate increases and the ambient temperature decreases, both the cell temperature rise (ΔT) and temperature difference (Δt) will become larger. In addition, whether it is the increase of the discharge rate or the decrease of the ambient temperature, a large temperature difference is easily generated in the longitudinal axis direction of the lithium-ion battery during discharge, but the temperature difference generated in the lateral axis direction is just obvious in the lower ambient temperature.

Seeing Puppetry: Winter Report from New York City

Seeing Puppetry: Winter Report from New York City

Algebra Tiles as Physical Manipulatives to Support Students’ Understanding of Linear Equations in One Variable

To help students in solving the linear equations in one variable, teacher can use a learning media such as algebra tiles. Algebra tiles are square and rectangle-shaped tiles that represent numbers and variables. Algebra tiles consist of three different-size pieces. The smallest tile is square shape and represents ± 1, the other tile is rectangular shape and represents ± x and the largest tile is large square shape that represents ± x2. The pieces are usually colour-coded so that one colour represents positive values and another color represents negative values. This research is a best practice that was conducted at class VII.7 SMPN 18 Tangerang. The aim of this research is to describe how the algebra tiles supports students’ understanding in solving linear equations in one variable. The competence achievement indicators are: modelling algebraic expressions using algebra tiles; solving linear equations in one variable using algebra tiles; solving linear equations in one variable without use algebra tiles. Data collection through photos, videos, worksheet and students’ work. Students did reducing and balancing ways to find the simple form of algebra tiles. The purpose of reducing or balancing of both sides of linear equations in one variable is to get how many square tiles that equals to one rectangular tile. Algebra tiles made students to be easier in solving linear equations in one variable. Students were very happy to learn mathematics using algebra tiles. The algebra tiles supports students’ understanding in solving linear equations in one variable.

Perfectly packing a square by squares of sidelength f(n)−t

In this paper, we prove that for any 1/2<t<1, there exists a positive integer N0 depending on t such that for any n0≥N0, squares of sidelength f(n)−t for n≥n0 can be packed with disjoint interiors into a square of area ∑n=n0∞f(n)−2t, if the function f satisfies some suitable conditions. The main theorem (Theorem 1.1) is a generalization of Tao's theorem in [15], which argued the case f(n)=n. As corollaries, we prove that there are such packings of squares when f(n) represents the nth element of either an arithmetic progression or the set of prime numbers. In these cases, we give effective lower bounds for N0 with respect to t. Furthermore, we consider the case that f(n) represents the nth element of the set of twin primes and prove that squares of sidelength f(n)−t for n≥n0 can be packed with disjoint interiors into a slightly larger square than theoretically expected.

Influence of pinning centers of different natures on surrounding vortices

Studies involving vortex dynamics and their interaction with pinning centers are an important issue to reach higher critical currents in superconducting materials. The vortex distribution around arrays of engineered defects, such as blind and through holes, may help to improve the superconducting properties. Thus, in this work, we used the time-dependent Ginzburg-Landau theory to investigate the vortex dynamics in superconductors of mesoscopic dimensions with a large central square defect with three different configurations: (i) a hole which passes through the sample (interface with the vacuum); (ii) a superconducting region with lower critical temperature Tc; and (iii) a region with a more robust superconductivity, i.e., with a higher Tc. Such systems can be envisaged as elementary building blocks of a macroscopic decorated specimen. Therefore, we evaluated the influence of different interfaces on the vortex dynamics and their effects in the field-dependent magnetization and time-dependent induced electric potential variation. The results show that the superheating field is independent from the nature of the defect. However, the currents crowd at the vertices of the through hole producing a lower degradation of the local superconductivity, which may increase the upper critical field. On the other hand, the last type of defect can be used to control the vortex dynamics in the main superconducting region around the defect with more accuracy. While the first two defects are attractive for the vortices, the third type is repulsive, being needed several penetrated vortices in the superconducting matrix to allow penetration of vortices into the higher Tc domain.

THE HEROIC PERIOD OF ARCHITECTURE IN UKRAINE

This article is devoted to the search for answers to several burning questions: what is the uniqueness of the industrial, civil and residential architecture of Ukraine in the 1920s - early 1930s? Does it need to be preserved? Why did foreign architectural criticism call these years the “heroic period of architecture”, yet the early Modernism of that time is still not appreciated at its true worth in its homeland? What was ‘heroic’ in the architecture of Ukraine and its first capital, Kharkiv? A brief analysis of the political and economic situation in which the newly-born independent Ukrainian Socialist Soviet Republic found itself is given. The most striking examples of modernist architecture in Ukraine are selected for argumentation. These are industrial giants such as Dniproges and Kharkiv Turbine Plant, the new cities of Zaporizhzhia and New Kharkiv, grandiose metropolitan projects: the ensemble of Svoboda Square—the largest square in Europe, as well as other examples of avant-garde architecture built or developed in those years are presented in the article. The reasons for their loss of authenticity in subsequent decades are revealed. Finally, the problem of preserving the heritage of Modernism in Ukraine in the conditions of a new war is touched upon.

Dimensionless numbers on columnar structured electrodes in hydrogen/oxygen polymer electrolyte fuel cells

Platinum columnar growth was found on anode and cathode catalysts after 6 months of operation in hydrogen/oxygen cells (1 A cm−2) from original smooth microspheres layers with loads ca. 1 mg cm−2. The application of symmetric and asymmetric large frequency square wave potential programs in strong sulphuric acid solutions for catalyst preparation showed those effects. For columnar electrodes, current and potential distributions are not those expected for smooth surfaces and constitute the main reason of a mismatching between theory and experimental data. The employ of exact analytical solutions arising from mass/charge balances are a better way to envisage electrochemical profiles instead of numerical solutions. Columnar catalysts can be parameterized by a trochoid curvilinear profile knowing the radius and pass (from ex situ STM images) rendering values ca. ½ for both parameters. Polarization and power density curves were also mimicked from the obtained current and cell potential distributions for the rough columnar surfaces. Finally, Wagner, Damkoehler and Graetz numbers that typify the electrochemical reactor were developed applying these parametric equations using local variations of tangential and normal velocities, from which a general dimensionless equation was obtained.

Point estimation following a two-stage group sequential trial.

Repeated testing in a group sequential trial can result in bias in the maximum likelihood estimate of the unknown parameter of interest. Many authors have therefore proposed adjusted point estimation procedures, which attempt to reduce such bias. Here, we describe nine possible point estimators within a common general framework for a two-stage group sequential trial. We then contrast their performance in five example trial settings, examining their conditional and marginal biases and residual mean square error. By focusing on the case of a trial with a single interim analysis, additional new results aiding the determination of the estimators are given. Our findings demonstrate that the uniform minimum variance unbiased estimator, whilst being marginally unbiased, often has large conditional bias and residual mean square error. If one is concerned solely about inference on progression to the second trial stage, the conditional uniform minimum variance unbiased estimator may be preferred. Two estimators, termed mean adjusted estimators, which attempt to reduce the marginal bias, arguably perform best in terms of the marginal residual mean square error. In all, one should choose an estimator accounting for its conditional and marginal biases and residual mean square error; the most suitable estimator will depend on relative desires to minimise each of these factors. If one cares solely about the conditional and marginal biases, the conditional maximum likelihood estimate may be preferred provided lower and upper stopping boundaries are included. If the conditional and marginal residual mean square error are also of concern, two mean adjusted estimators perform well.

Automorphisms of Cartan modular curves of prime and composite level

We study the automorphisms of modular curves associated to Cartan subgroups of $\mathrm{GL}_2(\mathbb Z/n\mathbb Z)$ and certain subgroups of their normalizers. We prove that if $n$ is large enough, all the automorphisms are induced by the ramified covering of the complex upper half-plane. We get new results for non-split curves of prime level $p\ge 13$: the curve $X_{\text{ns}}^+(p)$ has no non-trivial automorphisms, whereas the curve $X_{\text{ns}}(p)$ has exactly one non-trivial automorphism. Moreover, as an immediate consequence of our results we compute the automorphism group of $X_0^*(n):=X_0(n)/W$, where $W$ is the group generated by the Atkin-Lehner involutions of $X_0(n)$ and $n$ is a large enough square.

An improved method that incorporates the estimated runoff for peak discharge prediction on the Chinese Loess Plateau

An accurate prediction of peak discharge in watersheds is critical not only for water resource management, but also for understanding the complex relationships of hydrological processes. In this study, a modified peak discharge formula based on the Chemicals, Runoff, and Erosion from Agricultural Management Systems (CREAMS) model was developed by introducing rainfall intensity and soil moisture factors. The reliability of the proposed method was tested with data from 1464 storm events in 41 watersheds and was applied to 256 storm events in five remaining typical watersheds using the optimized parameters. The results indicate that the proposed method is highly accurate in terms of model efficiency, as determined by Nash–Sutcliffe efficiencies (NSEs) of 88.60%, 74.04%, and 90.12% during the calibration, validation, and application cases, respectively. Furthermore, it performed better than the original and modified CREAMS methods. Subsequently, using the parameters derived from the initial 41 watersheds and the runoff estimated using the modified Soil Conservation Service curve number (SCS–CN) method, the proposed method was used to predict the peak discharge from the last five typical watersheds. Large NSE (63.88–80.83%) and low root mean square error (RMSE) values (0.31–35.93 m3s-1) were obtained for the five watersheds. Overall, the proposed peak discharge model, combined with the modified SCS-CN method, may accurately predict event-based peak discharge and runoff for general applications under various hydrological and geomorphic conditions in the Loess Plateau region.

EXHIBITION TECHNIQUES OF INSTALLATIONS MADE ON THE BASIS OF THE IDENTITY OF THE PARIS LE BON MARCHÉ DEPARTMENTAL STORE SPACE

With the development of the industry, a department store type has emerged in order to provide easy access to the products. department store; It is a variety that exhibits different product groups with multiple departments in a single architectural volume and is offered for sale, and started to be applied as of the 18th century. The first example is the Le Bon Marché department store in Paris, France. These large square meter stores, which are also a center of socialization, have gone to identity structuring as alternatives have emerged and even contain the same products. Le Bon March”, being the first of its kind, grew with increasing demand and went into professional structuring in order to differentiate itself from the environment, and it was revised by the important architects of the period. As a result of the visual identity it has created, it has started to host both fashion product sales and eating and drinking activities by hosting many brands. The sociality that has developed as of the 21st century has brought a new dimension to the exhibition spaces by reflecting in the commercial action. Department stores have turned into centers for arts organizations as well as selling products in this direction. Installation type, which is the application and expression type of art, started to take place in department stores at this stage. Le Bon Marché's deep historical value has turned the art of installation into an area where it will integrate with spatial identity. At this stage, the spatial identity of the installations in the departmental store, the artist and the applications exhibited by integrating with the style in his works are seen. In the study, which is considered within the scope of qualitative research, the exhibition techniques created on the basis of spatial identity are handled with case studies and literature support, and it is reached how the installations can be rationalized in the spatial identity of the department store. Keywords: Department Store, Identity, Space Design, Installation, Exhibition Techniques.

Data Mining Method of Intelligent Market Management Based on Collaborative Recommendation Algorithm.

In order to solve the problems of low coverage and accuracy and large mean absolute error and root mean square error when traditional algorithms recommend market management data, this paper proposes an intelligent market management data mining method based on a collaborative recommendation algorithm. According to the preference value of the attribute characteristics of market management data, predict and score the attribute characteristics of market management data; use data mining technology to preprocess the information of market management data, combined with the design of collaborative filtering recommendation algorithm; and realize the collaborative filtering recommendation of market management data. With 50 recommendations, AGCAN improves the accuracy of MovieLens-1M by 43.81%, 5.43%, 1.87%, 0.42%, and 1.67%, respectively, compared with the five benchmark algorithms. For MovieLens-100K, compared with the five benchmark algorithms, AGCAN improves the accuracy by 51.17%, 10.52%, 3.37%, 0.1%, and 0.30%, respectively. Compared with the five benchmark algorithms, Amazon-baby and AGCAN have improved the accuracy by 34.37%, 28.12%, 31.25%, 29.1%, and 3.12%, respectively. The algorithm proposed in this paper uses a graph neural network to mine useful information between users and projects, but it lacks the use of other personalized interest information of users, such as user interest, user purchase time, and so on.

From lab to factory: A calibration transfer strategy from HSI to online NIR optimized for quality control of green tea fixation

Fixation is the key step of green tea processing, usually with moisture content as the quality evaluation indicator. Near-infrared (NIR) spectroscopy has been widely used in tea moisture detection but is mostly realized in the laboratory, and online detection in tea processing is limited. This study explores the possibility of calibration transfer from lab-based hyperspectral imaging (HSI) to online NIR to enable the rapid detection of moisture during the fixation step. Raw spectral data were preprocessed, and direct standardization (DS) and partial least-squares regression (PLS) were used for data calibration and modeling, respectively. The results showed that there were observable differences in the spectral data of the same sample obtained by different instruments. The prediction model based on HSI failed to be transferred directly to the online NIR and has a large root mean square error of prediction (RMSEP) value. Spectral preprocessing with a standard normal variate (SNV) transformation reduced the differences between the instruments. When 40 standard samples were used, the established transferable SNV-DS-PLS model based on HSI achieved the optimal prediction performance with a correlation coefficient of prediction (Rp), RMSEP, and ratio of prediction to deviation (RPD) of 0.94, 2.24%, and 2.76, respectively, for the 50 validated tea samples obtained from online NIR. In conclusion, the model transfer across instruments was successfully realized, and tea moisture detection was brought from the laboratory to the tea factory, which provided a reference model for online moisture detection for other agricultural products.

Polymer type effect on PLGA-based microparticles preparation by solvent evaporation method with single emulsion system using focussed beam reflectance measurement

Aim This study aimed to investigate the effect of polymer type on solidification rate of PLGA polymeric microparticles and particle size/distribution of the emulsion droplets/hardened PLGA polymeric microparticles during solvent evaporation process using FBRM (Focussed Beam Reflectance Measurement). Methods PLGA polymeric microparticles were prepared by an O/W solvent evaporation method using various PLGA polymers, including PLGA Resomer® RG503H, RG502H and RG752H. The particle size mean, chord length distribution (CLD), and chord count of the emulsion droplets/hardened microparticles were monitored by FBRM. The morphology of polymeric microparticles were characterised by optical microscopy and scanning electron microscopy (SEM). Results The transformation of the emulsion droplets into solid microparticles occurred within the first 30 (± 1.04), 34 (± 1.15) and 37 (± 0.82) min and square weighted mean chord lengths are 64.08 (± 3.18), 52.36 (± 5.27) and 42.18 (± 4.61) µm when PLGA Resomer® RG503H, RG502H and RG752H were used respectively. Larger square weighted mean chord length of PLGA polymeric microparticles gave lower chord counts. PLGA RG752H microparticles gave smallest square weighted mean chord length and the chord counts was the highest. The CLDs measured by FBRM showed that a larger particle size mean gave longer CLD and a lower peak of particle number. SEM data revealed that the morphology of microparticles was influenced by type and physical properties of polymer. Conclusions FBRM can be employed for online monitoring of the shift in the microparticle CLD and detect transformation of the emulsion droplets into solid microparticles during the solvent evaporation process. The microparticle CLD and transformation process were strongly influenced by polymer type.

Uniform inference in linear panel data models with two-dimensional heterogeneity

This paper studies uniform inference in a linear panel data model when the slope coefficients may exhibit heterogeneity over both the individual and time dimensions and they can be correlated with the regressors. We propose a generalized two-way fixed effects (GTWFE) estimation procedure to estimate the model. To establish the asymptotic properties of the GTWFE estimators, we invert a number of large dimensional square matrices by approximating them with quasi-Kronecker structured matrices. We establish the asymptotic normality of our GTWFE estimators and show that their convergence rates depend on the unknown degree of parameter heterogeneity. To make a uniform inference on the common slope component, we propose a novel triple-bootstrap procedure to estimate the asymptotic variance. Simulations show the superb performance of our estimators and inference procedure. We apply our method to study the relationship between savings and investments, and find significant parameter heterogeneity along both the individual and time dimensions.

Analysis of consumers' purchase behavior preference in e-commerce platform based on lightgbm algorithm

Aiming at the problem of large mean square error of regression coefficient in traditional e-commerce platform consumer purchase behavior preference analysis, this paper designs an e-commerce platform consumer purchase behavior preference analysis based on lightgbm algorithm. Firstly, the index system of consumer purchase behavior preference on e-commerce platform is constructed. Then, based on lightgbm algorithm, the classification variables of consumer purchase behavior preference data are trained. Then, the weight of consumer purchase behavior preference index is calculated. Finally, the analysis curve of consumer purchase behavior preference on e-commerce platform is fitted to realize preference analysis. The experimental results show that the mean square error of regression coefficient of the experimental group is significantly lower than that of the control group, which can solve the problem of large mean square error of regression coefficient of traditional preference analysis.

Double-layer acoustic metasurface for the suppression of the Mack second mode in hypersonic boundary-layer flow

An acoustic metasurface consisting of two layers of perforated plates is proposed for suppression of the Mack second mode in hypersonic boundary-layer flow. The upper layer with very tiny holes is permeable to acoustic waves and hardly alters the background hypersonic boundary-layer flow, offering rather low resistive and inductive components of surface acoustic impedance. The bottom layer with large and sparse square holes is attached to a rigid wall surface and forms a periodic array of chambers, each covering multiple holes of the upper layer, which can adjust the impedance phase by working as a capacitive component. Based on a linear stability analysis of hypersonic boundary-layer instability, such an acoustic metasurface satisfying the required surface impedance is designed and numerically investigated. The results show that the metasurface can efficiently suppress the Mack second mode over a relatively wide bandwidth. This work provides an alternative strategy for the design of porous walls for hypersonic boundary-layer stabilization.