Unified Structural Model Research Articles

The brain’s first “traffic map” through Unified Structural and Functional Connectivity (USFC) modeling

The brain’s white matter connections are thought to provide the structural basis for its functional connections between distant brain regions but how our brain selects the best structural routes for functional communications remains poorly understood. In this study, we propose a Unified Structural and Functional Connectivity (USFC) model and use an “economical assumption” to create the brain’s first “traffic map” reflecting how frequently each segment of the brain structural connection is used to achieve the global functional communication system. The resulting USFC map highlights regions in the subcortical, default-mode, and salience networks as the most heavily traversed nodes and a midline frontal-caudate-thalamus-posterior cingulate-visual cortex corridor as the backbone of the whole brain connectivity system. Our results further revealed a striking negative association between structural and functional connectivity strengths in routes supporting negative functional connections, as well as significantly higher efficiency metrics and better predictive performance for cognition in the USFC connectome when compared to structural and functional ones alone. Overall, the proposed USFC model opens up a new window for integrated brain connectome modeling and provides a major leap forward in brain mapping efforts for a better understanding of the brain’s fundamental communication mechanisms.

DESCRIPTION OF THE METHOD OF INTEGRAL EVALUATION OF THE EFFICIENCY OF DESIGNING ENERGY-EFFICIENT ECOLOGICAL SETTLEMENTS IN THE URBAN BUILDING SYSTEM

The article considers the description of the methods of integral assessment of the effectiveness of designing energy-efficient ecological settlements (hereinafter - EES) in the urban planning system, which allows to determine the potential opportunities of the territory for the formation and development of these urban planning entities. The conducted analysis will make it possible to identify "bottlenecks" in the development of territorial communities for the organization of energy-efficient ecological settlements, to develop practical recommendations for increasing the efficiency of designing energy-efficient ecological settlements, based on the existing potential of the territory. 
 As a result of the conducted research, a unified structural model of EES design was developed. The model consists of four stages, each of which defines structural elements and their relationships. A total of four stages of the model are defined. The first stage is the characterization of the territory. The territory characterization stage is one of the key stages in the system of designing ecological energy-efficient settlements. This stage involves research and data collection on the territory that will be used for the design of the ecological settlement. 
 The main goal of this stage is to determine the potential of the territory, as well as its limitations and problems that may arise during the implementation of the project. The main stages of territory characterization in the system of designing ecological energy-efficient settlements are defined as follows. Analysis of the topography of the territory: at this stage, the relief, hydrography, geological features of the territory and other factors that affect the natural environment are studied. Study of climatic conditions: the climatic regime of the territory is determined, which may include temperature, precipitation, seasonal changes, wind regime and other parameters. Soil research: at this stage, the structure, composition and quality of soils are studied, which are an important factor for the design of buildings and other engineering systems. Study of the flora and fauna: at this stage, the flora and fauna of the territory are studied, determining their diversity and level of protection. Assessment of the resource potential of the territory: at this stage, the analysis of the economic and social potential of the territory, including information on resources, is carried out. 
 For the analysis of the territories, the characteristics of sustainable development were determined as elements for the formation of the evaluation system. At the next stage, the efficiency factors of EES design were determined, which were formed into evaluation blocks: ecological, social, economic, geographical, technical, energy-saving. Based on the analysis, a system of indicators was formed, which became the basis for the formation of the evaluation model.

FUNDAMENTALS OF URBAN PLANNING ORGANIZATION OF ENERGYEFFICIENT ECOLOGICAL SETTLEMENTS TAKING INTO ACCOUNT ENERGY EFFICIENCY INDICATORS

The article considers the basics of urban planning organization of energy-efficient ecological settlements (hereinafter - EEP) taking into account energy efficiency indicators, since the organization of these urban planning formations is a multifaceted process that is associated with various factors that are considered in various scientific fields. 
 Energy-efficient ecological settlements - can become one of the options for a comfortable ecological and energy-saving living environment (ensuring the necessary microclimatic conditions in buildings, using natural technologies in lighting and ventilation, sustainable construction of low-rise, semi-underground and underground construction, application of natural architecture techniques, selection of local and ecological materials, assessment of the life cycle of the building, provision of alternative energy sources), which can become a full-fledged living space with all the necessary conditions, starting from providing people with homes, ending with places of work. 
 The main aspects of the development of energy-efficient ecological settlements have been identified, including: - the aspect of the functional organization of the territory, taking into account orientation according to the sides of the world, landscape assessment of the territory, etc.; 
 - aspect of permaculture design; - landscape and composition aspect; - the aspect of ecological and autonomous construction (use of natural or recycled materials, design of an energy-saving building form); - the aspect of independence from energy resources (solar energy, wind energy, geothermal energy, wave energy and biomass); - aspect of water resources management (complex system of drinking water management and management of reclaimed water for irrigation and toilets, rainwater storage system, biological wastewater treatment system, flood control system). - aspect of waste utilization and recycling (processing of solid household waste, composting of organic and human waste, used as biogas for obtaining energy and fertilizers for agriculture); - the aspect of rational planning of transport links and the road-trail network for the use of ecological transport; - aspect of socio-economic development (eco-industry, tourism, educational programs and community values).
 A unified structural model of EEP design has been developed. The unified structural model is a brief description of the stages of design (sequence of actions – algorithm) for further design, which includes four stages: Stage I – determination of the territory as an EEP, Stage II – determination of EEP factors, Stage III – analysis of initial data for further design, IV stage – design of EEP. Based on the results of the research, the stages of urban planning organization of energy-efficient ecological settlements were revealed, taking into account energy efficiency indicators (on the example of the Kharkiv region), which are presented in the form of detailed schemes.

Instantaneous cutting force model considering the material structural characteristics and dynamic variations in the entry and exit angles during end milling of the aluminum honeycomb core

The structural characteristics of the material and dynamic changes in the entry and exit angles are of great significance for the accurate prediction of the cutting force during milling of the aluminum honeycomb core. In this study, an instantaneous cutting force prediction model for the aluminum honeycomb core that comprehensively considers the porous structural characteristics of the material and dynamic changes in the entry and exit angles during the machining process was developed. A unified structural model for an aluminum honeycomb core with a regular hexagonal cell structure and excellent mechanical property was established. Based on the structural characteristics of the aluminum honeycomb core, three types of thin-walled edges were considered, and the dynamic changes in their entry and exit angles were investigated by considering the cutter radius, cutting width, honeycomb core wall thickness, and relative position between the cutter and thin-walled edge. An orthogonal-to-oblique cutting transformation approach that can effectively reflect the cutting characteristics of the material was adopted to calibrate the cutting force coefficients in which cutting experiments using different cutter geometries and parameters were conducted. The aluminum honeycomb core was fixed using green, high-efficiency cryogenic liquid nitrogen. To verify the reliability of the proposed model, a series of milling experiments were carried out and the experimental and simulation results were compared. It was found that the simulated cutting force is highly consistent with the experimental result. The proposed model can accurately predict the peak values of the cutting force in the x, y, and z directions, with an average prediction error of less than 10%.

Demand Expansion and Cannibalization Effects from Retail Store Entry: A Structural Analysis of Multichannel Demand

In this paper, we investigate the demand response of a firm’s existing customers to retail store entry and which aspects of the response are demand-expanding and which cannibalize online sales. The empirical goal of the paper is to separately identify the effects of customer-to-store distance on purchase frequency, channel choice, and expenditure per purchase, using transaction-level data from a multichannel apparel brand. Our identification strategy exploits within-customer variation in distance resulting from store entry during a period of rapid retail expansion. We establish retail distance effects using descriptive regressions before developing a unified structural model that affords rich counterfactual analyses and further controls for product category preferences. We find material effects of decreasing retail store distance on purchase frequency and retail channel choice but not expenditures per purchase. Our structural model ascribes mechanisms to these effects in the form of increased brand consideration, higher retail utility from nonmonetary factors (e.g., reduced driving times), and infungibility of monetary transportation costs with budgets for apparel. Our estimates imply that a 10% reduction in retail store distance increases retail channel expenditures by 1.9% and decreases online channel expenditures by 1.2%, resulting in a 0.4% increase in total expenditures. Through counterfactual experiments, we demonstrate that retail expansion can ultimately limit the ability of the firm to price discriminate across channels because reducing transportation costs weakens the firm’s ability to enforce channel-based segmentation schemes. This paper was accepted by Matthew Shum, marketing. Supplemental Material: The online appendix and data are available at https://doi.org/10.1287/mnsc.2022.4308 .

A Structural Equation Model on Happiness among Adolescents in South Korea

Purpose This study was conducted to develop a unified structural model that defines relationships among the factors that affect happiness in adolescents in South Korea. Methods This study was performed using the dataset from the 2018 Korean Children and Youth Panel Survey (KCYPS). The study participants were 2590 adolescents recruited through probability proportional to size (PPS) sampling. The data were analyzed using descriptive statistics, Pearson’s correlation coefficient, and structural equation modeling to determine the factors that influence adolescents' happiness. Results Our proposed structural model demonstrated a fine fitness level. Our proposed structural model was also able to describe happiness for adolescents with 68.2% accuracy. Positive social support, high self-esteem, and low depression were confirmed as key factors that influence happiness among adolescents. Meanwhile, physical symptoms were not shown to influence happiness for adolescents in South Korea. Conclusion We suggest that intervention is required to increase happiness in adolescents. Specifically, there is a need for combinational interventions that help adolescents in South Korea increase their social support and self-esteem while reducing their depression. Key words: Happiness; Models; Structural; Adolescent; Social support 주요어: 행복감, 구조모형, ì²­ì†Œë „, ì‚¬íšŒì  지지

Utilizing a unified structure model in (3 + 1)-dimensional superspace to identify a homologous phase (Ga1−αAlα)2O3(ZnO)min ZnO-based thermoelectric composites

A unified structure model in (3 + 1)-dimensional superspace proved suitable for identification of a homologous phase (Ga1−αAlα)2O3(ZnO)mby the profile fitting of powder X-ray diffraction intensities for thermoelectric composite materials in the pseudoternary system ZnO–Al2O3–Ga2O3. A homologous compound of the phase parameterm≃ 37 was found to coexist with (Al,Ga)-doped ZnO in samples sintered at 1723 K in air. The thermoelectric properties of the composite materials were closely related to the phase fractions. The higher the phase fraction of (Al,Ga)-doped ZnO with the wurtzite structure, the higher the electrical conductivity. On the other hand, the homologous compound with the long-period structure was effective in lowering the thermal conductivity of the materials.

Методическая система формирования инфографической компетенции курсантов военного вуза

The research objective includes development and presentation of the author’s original methodology to develop military students’ infographic competence in the process of foreign language teaching. The article considers the problem of using infographics while teaching a foreign language to military students with the purpose to develop their infographic competence, the essence and specificity of which are revealed. The researcher’s attention is focused on identifying structural components of a methodological system for formation of military students’ infographic competence. Scientific originality of the study lies in the fact that the author develops a unified structural model of her original methodological system, which allows achieving optimal organization of foreign language teaching focused on forming military students’ infographic competence. The research findings justify efficiency of the proposed methodology.

Fuzzy Reliability Modeling of Mechanical Meta-action Assembly Accuracy

Meta-action assembly units are the basic units to ensure the reliability of mechanical function. For the problem that the reliability of meta-action assembly units are difficult to be finely modeled. Combined with the fuzziness of assembly process, this paper introduces fuzzy theory into the reliability analysis of meta-action assembly accuracy.By analyzing the structure of meta-action assembly units, it is concluded that meta-action assembly units are composed of support member, power source, transmission fastener and actuator.Then, an unified structural model of meta-action assembly units is established; according to the mechanism of assembly accuracy, the accuracy information of a meta-action assembly unit is mapped to each assembly item (assembly item is consisted of individual part feature and corresponding part feature). Combined with the fuzzy feature of assembly information, the concepts of assembly accuracy reliability and assembly accuracy fuzzy reliability are proposed. By analyzing the fuzzy characteristics of assembly accuracy of assembly items, membership function of assembly accuracy is determined. According to probability definition of the fuzzy events, a fuzzy reliability model of the meta-action assembly accuracy is established. In view of whether the assembly project of scientific research enterprise has faults, a large number of historical data are analyzed, and the overall 0-1 distribution of observation data is obtained. Precision test of fuzzy reliability model is got on by maximum likelihood estimation of the 0-1 distribution. The example shows that the reliability value obtained by using the model is different from the test result by 0.0029. The results indicate that the method has greater feasibility, simplicity and flexibility.

Business environment reforms, innovation and firm productivity in transition economies

This paper explores the role of business environment reforms in enhancing innovation and the productivity performance of individual firms in transition economies. Using a large sample of firm-level data from the Business Environment and Enterprise Performance Survey (BEEPS V round) across 28 transition economies, this paper examines the link between business environment reforms and firm R&D and innovation and productivity performance within a unified structural model. In this paper, we utilize a novel approach to measure business environment reforms. As a basis for constructing a business environment reforms (BER) index, we use subjective valuations of the constraints facing firms for doing businesses vis-a-vis various dimensions of the business environment. The index is calculated as a difference between the aggregated mean scores for innovator and non-innovator firms (by country and size of locality). The lower the difference, the better the business environment is in terms of providing firms with more stimulus to invest in innovations. The estimates of the structural model proved our hypothesis on the impact of business environment reforms on the relationships between R&D investments, innovation and labor productivity. We found strong support for the impact of the BER index on the intensity of R&D and innovation as well as on labor productivity. This paper supports the early findings that R&D is an important determinant of innovation and that innovation is a driver of labor productivity. However, our outcomes show that the patterns of the influence on a firm’s performance differ across the various dimensions of the business environment.

A unifying structural and functional model of the coronavirus replication organelle: Tracking down RNA synthesis.

Zoonotic coronavirus (CoV) infections, such as those responsible for the current severe acute respiratory syndrome-CoV 2 (SARS-CoV-2) pandemic, cause grave international public health concern. In infected cells, the CoV RNA-synthesizing machinery associates with modified endoplasmic reticulum membranes that are transformed into the viral replication organelle (RO). Although double-membrane vesicles (DMVs) appear to be a pan-CoV RO element, studies to date describe an assortment of additional CoV-induced membrane structures. Despite much speculation, it remains unclear which RO element(s) accommodate viral RNA synthesis. Here we provide detailed 2D and 3D analyses of CoV ROs and show that diverse CoVs essentially induce the same membrane modifications, including the small open double-membrane spherules (DMSs) previously thought to be restricted to gamma- and delta-CoV infections and proposed as sites of replication. Metabolic labeling of newly synthesized viral RNA followed by quantitative electron microscopy (EM) autoradiography revealed abundant viral RNA synthesis associated with DMVs in cells infected with the beta-CoVs Middle East respiratory syndrome-CoV (MERS-CoV) and SARS-CoV and the gamma-CoV infectious bronchitis virus. RNA synthesis could not be linked to DMSs or any other cellular or virus-induced structure. Our results provide a unifying model of the CoV RO and clearly establish DMVs as the central hub for viral RNA synthesis and a potential drug target in CoV infection.

A multi-branch hand pose estimation network with joint-wise feature extraction and fusion

The study of 3D hand pose estimation from a single depth image is regarded as a detection-based or regression-based problem among most of the existing deep learning-based methods, and this approach does not fully exploit the geometry of the hand, such as its structural and physical constraints. To overcome these weaknesses, we design a network with three simple parallel branches that correspond to the three functional parts of the hand. This observation is motivated by the biological viewpoint that each finger plays a different role in performing grasping and manipulation. In each branch, we perform a more detailed regression in two stages – top-down joint location regression followed by bottom-up hand pose regression – which fully exploits both the local and global structure of a hand. Finally, we further make use of the hand structure and physical constraints to refine each joint by its auxiliary points. The proposed network is a unified structure and function model that is more appropriate for hand pose estimation. Our system does not require pose pre-processing or feedback since it can directly perform training and predicting from end-to-end. The experimental results on three public datasets demonstrate that the proposed system achieves performance comparable to state-of-the-art methods.

Company?s intellectual capital impact on market value of Baltic countries listed enterprises

Research background: Currently the topic of a company?s intellectual capital is being widely investigated by various researchers. Nevertheless, only a small number of studies on the company?s intellectual capital impact on its market value were conducted. What is more, the concept of a company?s intellectual capital itself is not unified. There are some discrepancies in defining a company?s intellectual capital, unifying structural model of the company?s intellectual capital, and harmonizing the research methods and models of how to evaluate a company?s intellectual capital.
 Purpose of the article: The aim of the article is to examine various scientific approaches of the company?s intellectual capital and its impact on the market value of a respective company; to prepare a model of company?s intellectual capital and its impact on the market value. What is more, the aim of this article is to check and test the model effectiveness using an example of the Baltic States listed companies.
 Methods: Data on 58 Baltic States? companies that are listed in Nasdaq Baltic stock exchange were taken as the basis of the research. Based on four component model (human capital, structural capital, juridical capital, relational capital) a set of indicators for assessing company?s intellectual capital was formed. Expert evaluation was used in order to assign weights for different structural parts of intellectual capital. An exploratory factor analysis was conducted in order to find out what factors are the most significant for a company?s intellectual capital. In order to find out how specific elements affect company?s intellectual capital, a pair-wise multiple correlation and regression analysis were used. An average comparison method was used to reveal differences between companies of different countries.
 Findings & Value added: The study contributes to the Baltic States? knowledge on intellectual capital. It was detected that it is appropriate to use human capital, structural capital, juridical capital, and relational capital structural parts as components of company?s intellectual capital while investigating its impact on market value of a respective company. According to the obtained results, the model of a company?s intellectual capital and its impact on the market value was created, optimized, and its validity checked using exploratory factor analysis. The model was used to test the Baltic States listed companies and how their intellectual capital affects the market value. It was identified that intellectual capital in the listed companies of the Baltic States has a positive impact on their market value. Nevertheless, the study revealed that intellectual capital structural parts do not equally affect the market value of listed companies. The findings support the conclusion that human capital and relational capital have the greatest influence on the market value of listed companies. Companies where structural capital comprises the largest proportion of intellectual capital had lower levels of intellectual capital aggregated index, which could be examined in future studies.

A unified structural model of the mammalian translocator protein (TSPO).

The translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor (PBR), is a membrane protein located on the outer mitochondrial membrane. Experimentally-derived structures of mouse TSPO (mTSPO) and its homologs from bacterial species have been determined by NMR spectroscopy and X-ray crystallography, respectively. These structures and ligand interactions within the TSPO binding pocket display distinct differences. Here, we leverage experimental and computational studies to derive a unified structural model of mTSPO in the presence and absence of the TSPO ligand, PK11195, and study the effects of DPC detergent micelles on the TSPO structure and ligand binding. From this work, we conclude that that the lipid-mimetic system used to solubilize mTSPO for NMR studies thermodynamically destabilizes the protein, introduces structural perturbations, and alters the characteristics of ligand binding. Furthermore, we used Rosetta to construct a unified mTSPO model that reconciles deviating features of the mammalian and bacterial TSPO. These deviating features are likely a consequence of the detergent system used for structure determination of mTSPO by NMR. The unified mTSPO model agrees with available experimental NMR data, appears to be physically realistic (i.e. thermodynamically not frustrated as judged by the Rosetta energy function), and simultaneously shares the structural features observed in sequence-conserved regions of the bacterial proteins. Finally, we identified the binding site for an imaging ligand VUIIS8310 that is currently positioned for clinical translation using NMR spectroscopy and propose a computational model of the VUIIS8310-mTSPO complex.

Stacking sequence variations in vaterite resolved by precession electron diffraction tomography using a unified superspace model

As a metastable phase, vaterite is involved in the first step of crystallization of several carbonate-forming systems including the two stable polymorphs calcite and aragonite. Its complete structural determination would consequently shed important light to understand scaling formation and biomineralization processes. While vaterite’s hexagonal substructure (a0 ~ 4.1 Å and c0 ~ 8.5 Å) and the organization of the carbonate groups within a single layer is known, conflicting interpretations regarding the stacking sequence remain and preclude the complete understanding of the structure. To resolve the ambiguities, we performed precession electron diffraction tomography (PEDT) to collect single crystal data from 100 K to the ambient temperature. The structure was solved ab initio and described over all the temperature range using a unified modulated structure model in the superspace group C12/c1(α0γ)00 with a = a0 = 4.086(3) Å, b = sqrt{{bf{3}}}a0 = 7.089(9) Å, c = c0 = 8.439(9) Å, α = β = γ = 90° and q = tfrac{{bf{2}}}{{bf{3}}}a* + γc*. At 100 K the model presents a pure 4-layer stacking sequence with γ = tfrac{{bf{1}}}{{bf{2}}} whereas at the ambient temperature, ordered stacking faults are introduced leading to γ < tfrac{{bf{1}}}{{bf{2}}}. The model was refined against PEDT data using the dynamical refinement procedure including modulation and twinning as well as against x-ray powder data by the Rietveld refinement.

Identification of a secondary phase Ga2O3(ZnO) m in Ga-doped ZnO thermoelectric materials by a (3 + 1)-dimensional superspace model

A unified structure model for the homologous compounds Ga2O3(ZnO) m in (3 + 1)-dimensional superspace was modified by refinements for samples of Ga2O3:ZnO = 1:n (n = 15, 23, 28, 33, 38). The first-order sine terms in the modulation functions decreased with increasing phase index m. The diffraction intensities of the thermoelectric material Ga2O3:ZnO = 1:98 were best fitted by a two-phase model containing the wurtzite structure (Ga-doped ZnO) and the homologous compound Ga2O3(ZnO) s , where s = 38.

A Structural Equation Model on Korean Adolescents' Excessive Use of Smartphones

PurposeAuthors develop a unified structural model that defines multirelationships between systematic factors causing excessive use of smartphones and the corresponding results. MethodsA survey was conducted with adolescents who live in Seoul, Pusan, Gangneung, Donghae, and Samcheok from February to March 2016. Authors used SPSS, version 22.0, and AMOS, version 22.0, to analyze the survey results at a .05 significance level. To investigate demographic characteristics of the participants and their variations, descriptive analysis was used. The maximum likelihood estimate method was adopted to verify the fitness of the hypothetical model and the hypotheses therein. Authors used χ2 statistics, goodness-of-fit index, adjusted goodness-of-fit index, comparative fit index, normed fit index, incremental fit index, root mean square residual, and root mean square error of approximation to verify the fitness of our structural model. Results(1) The proposed structural model demonstrated a fine fitness level. (2) The proposed structural model could describe the excessive use of a smartphone with 88.6% accuracy. (3) The absence of the family function and relationship between friends, impulsiveness, and low self-esteem were confirmed as key factors that cause an excessive use of smartphones. (4) Furthermore, impulsiveness and low self-esteem are closely related to the absence of family functions and relations between friends by 68.3% and 54.4%, respectively. ConclusionAuthors suggest that nursing intervention programs from various angles are required to reduce adolescents' excessive use of smartphones. For example, family communication programs would be helpful for both parents and children. Consultant programs about relationships with friends would also be helpful.

DELIMITATION OF THE TERRITORIES BEING UNDER THE INFLUENCE OF AGGLOMERATION

Presently, the significance of major cities is increasing. This is confirmed by the trends in the spatial development of territories. Major cities are the centres of gravitation of closely located settlements, and together they form an integrated system – an agglomeration. Over the past few years, such spatial formations as agglomeration become more and more popular. In the course of study of agglomeration processes there are the issues most of which do not yet have a decisive answer, in particular the issue of agglomeration territories delimitation. With this in view, the paper considers existing domestic and foreign methods for delimiting agglomerations. The spatial structure of an agglomeration was determined. Key criteria used for distinguishing a territory as an agglomeration are suggested. There has been developed the method of delimitation of the territories being under the influence of agglomeration, including the development of a unified structural model. The structure of the model is made up of five stages, namely: recognition of the territory as agglomeration; characterization of the city centre (core) of the agglomeration; delimitation of the territories being under the influence of agglomeration in two directions (considering and ignoring the administrative and territorial division); characterization of the territories being under the influence of agglomeration; checking the development of the territories being under the influence of agglomeration. Indicators were developed to evaluate the degree of appurtenance of a region to zone of agglomeration influence. They help identifying better the most investment attractive administrative regions and determine those of them that are perspective and can be included in the future in the zone of influence of an agglomeration.

Orientational order-disorder γ ↔ β ↔ α′ ↔ α phase transitions in Sr2B2O5 pyroborate and crystal structures of β and α phases

Crystal structures of γ-, β- and α-Sr2B2O5 polymorphs resulting from the γ ↔ (at 565 K) β ↔ (at 637 K) α′ ↔ (at 651 K) α sequence of reversible first-order phase transitions are studied by high-temperature single-crystal X-ray diffraction, high-temperature X-ray powder diffraction, differential scanning calorimetry and impedance spectroscopy. Out of these phases, the structure of γ-Sr2B2O5 was already known whereas the structures of β- and α-Sr2B2O5 were determined for the first time. The sequence of phase transitions is associated with an unusual change of symmetry, with triclinic intermediate β-Sr2B2O5 phase and monoclinic low-temperature γ-Sr2B2O5 as well as high-temperature α-Sr2B2O5 phase. Taking the α-Sr2B2O5 phase with space group P21/c as a parent structure, the γ-Sr2B2O5 phase was refined as a twofold superstructure with symmetry P21/c, whereas the β-Sr2B2O5 phase was a sixfold superstructure with symmetry P{\overline 1}. To construct a unified structure model for all Sr2B2O5 modifications, phases of γ- and β-Sr2B2O5 were also refined as commensurately modulated structures using the basic unit cell of the parent α-Sr2B2O5. The phase transitions are related to the orientational order–disorder arrangement of B2O5 pyroborate groups, where the degree of disorder grows towards the high-temperature phase. Thermal expansion is strongly anisotropic and dictated by preferable orientations of BO3 triangles in the structure. The intermediate phase α′-Sr2B2O5, stable over a narrow temperature range (637–651 K), features the largest anisotropy of expansion for the known borates: α11 = 205, α22 = 57, α33 = −81 × 10−6 K−1.

Galvanomagnetic Transport Properties and Gilbert Damping in Ferromagnetic PdCo Alloys

The spin-orbit driven phenomena, such as the anisotropic magnetoresistance (AMR), the anomalous Hall conductivity (AHC), and the Gilbert damping in disordered fcc-PdCo alloys were studied from first principles using a unified electronic structure model. In PdCo alloys around equiconcentration composition partial order can exist and we investigate its effect on the transport properties and Gilbert damping. It was found that the partial order significantly improves agreement of the calculated AMR ratio and the experiment as compared to the random alloy case. The influence of ordering on the AHC and the Gilbert damping is much weaker.