Structure Factor Research Articles

Correlation-induced viscous dissipation in concentrated electrolytes.

Electrostatic correlations between ions dissolved in water are known to impact their transport properties in numerous ways, from conductivity to ion selectivity. The effects of these correlations on the solvent itself remain, however, much less clear. In particular, the addition of salt has been consistently reported to affect the solution's viscosity, but most modeling attempts fail to reproduce experimental data even at moderate salt concentrations. Here, we use an approach based on stochastic density functional theory, which accurately captures charge fluctuations and correlations. We derive a simple analytical expression for the viscosity correction in concentrated electrolytes, by directly linking it to the liquid's structure factor. Our prediction compares quantitatively to experimental data at all temperatures and all salt concentrations up to the saturation limit. This universal link between the microscopic structure and viscosity allows us to shed light on the nanoscale dynamics of water and ions under highly concentrated and correlated conditions.

Anisotropic-Isotropic Transition of Cages at the Glass Transition.

Characterizing the local structural evolution is an essential step in understanding the nature of glass transition. In this work, we probe the evolution of Voronoi cell geometry in simple glass models by simulations and colloid experiments, and find that the individual particle cages deform anisotropically in supercooled liquid and isotropically in glass. We introduce an anisotropy parameter k for each Voronoi cell, whose mean value exhibits a sharp change at the mode-coupling glass transition ϕ_{c}. Moreover, a power law of packing fraction ϕ∝q_{1}^{d} is discovered in the supercooled liquid regime with d>D, in contrast to d=D in the glass regime, where q_{1} is the first peak position of structure factor, and D is the space dimension. This power law is qualitatively explained by the change of k. The active motions in supercooled liquid are spatially correlated with long axes rather than short axes of Voronoi cells. In addition, the dynamic slowing down approaching the glass transition can be well characterized through a modified free-volume model based on k. These findings reveal that the structural parameter k is effective in identifying the structure-dynamics correlations and the glass transition in these systems.

Attosecond electron microscopy by free-electron homodyne detection

Time-resolved electron microscopy aims to track nanoscale excitations and dynamic states of matter at a temporal resolution ultimately reaching the attosecond regime. Periodically time-varying fields in an illuminated specimen cause free-electron inelastic scattering, which enables the spectroscopic imaging of near-field intensities. However, access to the evolution of nanoscale fields and structures within the cycle of light requires sensitivity to the optical phase. Here we introduce free-electron homodyne detection as a universally applicable approach to electron microscopy of phase-resolved optical responses at high spatiotemporal resolution. In this scheme, a phase-controlled reference interaction serves as the local oscillator to extract arbitrary sample-induced modulations of a free-electron wavefunction. We demonstrate this principle through the phase-resolved imaging of plasmonic fields with few-nanometre spatial and sub-cycle temporal resolutions. Due to its sensitivity to both phase- and amplitude-modulated electron beams, free-electron homodyne detection measurements will be able to detect and amplify weak signals stemming from a wide variety of microscopic origins, including linear and nonlinear optical polarizations, atomic and molecular resonances, and attosecond-modulated structure factors.

A review of existing methods for predicting leachate production from municipal solid waste landfills.

Landfilling is one of the predominant methods of municipal solid waste (MSW) disposal worldwide, while the generation of leachate, a kind of toxic wastewater, is among the primary factors behind landfill instability and environmental contamination problems. Precise prediction of leachate production is crucial to landfill safety evaluation and design. This paper presents a comprehensive review of methods for predicting leachate production from MSW landfills. Firstly, compositional characteristics of MSW and leachate generation mechanism are analysed. Factors influencing leachate production are summarised based on the generation mechanism, including the components of MSW, climatic conditions, landfill structure, and environmental factors. Then, we classified the existing methods for predicting leachate production into four categories: water balance formula, water balance model, empirical formula, and artificial intelligence model methods. Advantages, disadvantages, and applicability of different leachate production prediction methods are compared and analysed. Furthermore, limitations in the existing leachate production prediction methods for MSW landfills and scope for future research are discussed.

Family Fat Talk Questionnaire - Polish adaptation.

One of the dangerous phenomena that reinforces a negative attitude towards one's own body is the so-called family fat talk1, i.e. conversations initiated by carers/siblings selfdevaluing body shapes and sizes. The aim of our own research was to adapt the self-report two-factor tool Family Fat Talk Questionnaire (FFTQ) by MacDonald et al., which may be used in the prophylaxis of maladaptive behaviours towards eating and the body, especially in the adolescent population. The study covered 391 people at the turn of late adolescence and early adulthood. The following were used: (1) personal questionnaire - to control secondary variables (e.g. gender, BMI, difference between the actual and desired body weight), (2) Family Fat Talk Questionnaire in the Polish language version (FFTQ-PL) and (3) Kwestionariusz wizerunku ciała (KWCO) by A. Głębocka to check external accuracy. The research results indicate that the FFTQ-PL has satisfactory reliability and measurement accuracy, and its two-factor structure (factor 1 - "I"; factor 2 - "Family") has been confirmed. This measure is worth using in screening studies to identify people - especially adolescents - engaging in self-devaluing conversations within the family. It turns out that fat talk, especially in the case of people with a negative body image, can become a risk factor for risky eating practices.

Differences of bacterioplankton communities between the source and upstream regions of the Yangtze River: microbial structure, co-occurrence pattern, and environmental influencing factors.

The source area of the Yangtze River is located in the hinterland of the Qinghai-Tibet Plateau, which is known as the "Earth's third pole." It is the water conservation area and the natural barrier of the ecosystem of the Yangtze River basin. It is also the most sensitive area of the natural ecosystem, and the ecological environment is very fragile. Microorganisms play key roles in the biogeochemical processes of water. In this paper, the bacterioplankton communities in the source and upstream regions of the Yangtze River were studied based on 16S rRNA high-throughput sequencing, and their environmental influencing factors were further analyzed. Results showed that the upstream region had higher richness and diversity than the source region. The predominant bacterial phyla in the source and upstream regions were Proteobacteria, Firmicutes, and Actinobacteriota. The bacterial phyla associated with municipal pollution and opportunistic pathogen, such as Firmicutes and Actinobacteriota, were more abundant in the upstream. By contrast, distinct planktonic bacterial genera associated with mining pollution, such as Acidiphilium and Acidithiobacillus, were more abundant in the source region. The co-occurrence network showed that the interaction of bacterioplankton community is more frequent in the upstream. The bacterioplankton community compositions, richness, and functional profiles were affected by the spatial heterogeneity. Moreover, variation partitioning analysis further confirmed that the amount of variation in the source region independently explained by variables of altitude was the largest, followed by water nutrient. This paper revealed the spatial distribution of planktonic bacterial communities in the source and upstream regions of the Yangtze River and its correlation with environmental factors, providing information support for ensuring the health and safety of aquatic ecosystems in the Yangtze River Basin.

Dynamic structure factor of undulating vesicles: finite-size and spherical geometry effects with application to neutron spin echo experiments.

We consider the dynamic structure factor (DSF) of quasi-spherical vesicles and present a generalization of an expression that was originally formulated by Zilman and Granek (ZG) for scattering from isotropically oriented quasi-flat membrane plaquettes. The expression is obtained in the form of a multi-dimensional integral over the undulating membrane surface. The new expression reduces to the original stretched exponential form in the limit of sufficiently large vesicles, i.e., in the micron range or larger. For much smaller unilamellar vesicles, deviations from the asymptotic, stretched exponential equation are noticeable even if one assumes that the Seifert-Langer leaflet density mode is completely relaxed and membrane viscosity is neglected. To avoid the need for an exhaustive numerical integration while fitting to neutron spin echo (NSE) data, we provide a useful approximation for polydisperse systems that tests well against the numerical integration of the complete expression. To validate the new expression, we performed NSE experiments on variable-size vesicles made of a POPC/POPS lipid mixture and demonstrate an advantage over the original stretched exponential form or other manipulations of the original ZG expression that have been deployed over the years to fit the NSE data. In particular, values of the membrane bending rigidity extracted from the NSE data using the new approximations were insensitive to the vesicle radii and scattering wavenumber and compared very well with expected values of the effective bending modulus ([Formula: see text]) calculated from results in the literature. Moreover, the generalized scattering theory presented here for an undulating quasi-spherical shell can be easily extended to other models for the membrane undulation dynamics beyond the Helfrich Hamiltonian and thereby provides the foundation for the study of the nanoscale dynamics in more complex and biologically relevant model membrane systems.

The Effect of Islamic Corporate Governance, Firm Characteristic on Capital Structure and Financial Performance of Sharia Commercial Banks Registered the Financial Services Authority

This study examines the relationship between Islamic corporate governance, firm characteristics on capital structure and financial performance in Islamic Commercial Banks. The data analysis technique uses Partial Least Square (PLS), with structural equations (SEM) based on components or variants, on annual data from 2017 to 2021. The findings show that three determinants significantly affect the financial performance of the five hypotheses proposed. Islamic corporate governance has a significant effect on financial performance in a negative direction, and a significant positive effect on capital structure Firm characteristic has no significant effect on capital structure and financial performance. Capital structure factors influence financial performance. The practical implications of this study emphasize the important role of the sharia supervisory board and independent commissioners in improving the financial performance of Islamic commercial banks

Latitudinal variation and driving factors of above-ground carbon proportion of large trees in old-growth forests across China

Large trees play a vital role in forest carbon stocks, dominating the distribution of community biomass. However, climate change and deforestation are reducing large trees globally, resulting in regional differences in their contribution to carbon stocks. Here, we examined the latitudinal change pattern and drivers of large trees' contributions to stand carbon stocks. Above-ground carbon storage was calculated for 530 plots in old-growth forests across China. Linear regression was used to calculate latitudinal variation in the proportion of above-ground carbon in large trees (i.e., AGC proportion). Variance partitioning and multiple linear regression were used to calculate the relative importance of species diversity, stand structure, functional traits, and environmental factors to AGC proportion. The study found that AGC proportion decreased with increasing latitude, averaging at 64.44 %. Stand structure, particularly the coefficient of variation of DBH, was identified as the key drivers of the AGC proportion. The number of common species (Hill's 1D) had no direct effect on the AGC proportion, while wood density, maximum tree height, and leaf nitrogen-to‑phosphorus ratio showed negative effects. The mass-ratio effects on AGC proportion were stronger than diversity effects. Climate variables primarily affected the AGC proportion through stand variables. These results indicate that simultaneously managing high diversity and AGC proportion may pose challenges. Moreover, considering the substantial contribution of large trees to carbon stocks, their storage capacity and sensitivity to environmental changes exert significant control over forest carbon cycles. Therefore, preserving and enhancing the carbon sink function of old-growth forests in the face of climate change and disturbance may depend primarily on protecting existing large trees and soon-to-be large-diameter trees.

Ab Initio Path Integral Monte Carlo Simulations of the Uniform Electron Gas on Large Length Scales.

The accurate description of non-ideal quantum many-body systems is of prime importance for a host of applications within physics, quantum chemistry, materials science, and related disciplines. At finite temperatures, the gold standard is given by ab initio path integral Monte Carlo (PIMC) simulations, which do not require any empirical input but exhibit an exponential increase in the required computation time for Fermionic systems with an increase in system size N. Very recently, computing Fermionic properties without this bottleneck based on PIMC simulations of fictitious identical particles has been suggested. In our work, we use this technique to perform very large (N ≤ 1000) PIMC simulations of the warm dense electron gas and demonstrate that it is capable of providing a highly accurate description of the investigated properties, i.e., the static structure factor, the static density response function, and the local field correction, over the entire range of length scales.

Designer pair statistics of disordered many-particle systems with novel properties.

The knowledge of exact analytical functional forms for the pair correlation function g2(r) and its corresponding structure factor S(k) of disordered many-particle systems is limited. For fundamental and practical reasons, it is highly desirable to add to the existing database of analytical functional forms for such pair statistics. Here, we design a plethora of such pair functions in direct and Fourier spaces across the first three Euclidean space dimensions that are realizable by diverse many-particle systems with varying degrees of correlated disorder across length scales, spanning a wide spectrum of hyperuniform, typical nonhyperuniform, and antihyperuniform ones. This is accomplished by utilizing an efficient inverse algorithm that determines equilibrium states with up to pair interactions at positive temperatures that precisely match targeted forms for both g2(r) and S(k). Among other results, we realize an example with the strongest hyperuniform property among known positive-temperature equilibrium states, critical-point systems (implying unusual 1D systems with phase transitions) that are not in the Ising universality class, systems that attain self-similar pair statistics under Fourier transformation, and an experimentally feasible polymer model. We show that our pair functions enable one to achieve many-particle systems with a wide range of translational order and self-diffusion coefficients D, which are inversely related to one another. One can design other realizable pair statistics via linear combinations of our functions or by applying our inverse procedure to other desirable functional forms. Our approach facilitates the inverse design of materials with desirable physical and chemical properties by tuning their pair statistics.

Changes in Functional Groups and Crystal Structure of Coal Tar Pitch with Respect to Carbonization Temperature

In this study, changes in the microstructure of coal-tar pitch (CTP) during successive processes, including pyrolysis, polycondensation, and crystallization, were examined in connection with the resulting variations in structure factors, as measured by X-ray diffraction (XRD) analysis, and functional groups, as confirmed by Fourier transform infrared (FTIR) spectroscopy. To this end, four zones were defined based on variations in crystallinity, which were indicated by d002 and Lc. Each zone was further characterized by interpreting crystallinity development in relation to changes in functional groups and specimen height. At around 400 °C, polycondensation occurred as the C-Har and C-Hal peaks decreased in intensity. These peak reductions coincided with the formation of mesophase spheres, resulting in enhanced crystallinity. Subsequently, at around 500 °C, the peak intensity of C-H and COOH decreased, which was attributed to the release of large amounts of gases. This led to sharp volume changes and a temporary reduction in crystallinity. All these results suggest that changes in the functional groups of CTP at lower temperatures (600 °C or less) during the carbonization process are closely associated with variations in its crystallinity. The major findings of the present study provide valuable insights for designing highly effective processes in the manufacturing of synthetic graphite blocks using CTP as a binder material, including by selecting appropriate temperature ranges to minimize volume expansion and crystallinity degradation and determining the lowest possible carbonization temperature to ensure adequate binder strength.

Importance of forest stand structures for gross rainfall partitioning on China’s Loess Plateau

Large-scale ecological restoration in the arid and semi-arid Loess Plateau region of northern China is challenged by the intensifying water stress due to the changes in precipitation regimes. Although the importance of Gross Precipitation Partitioning (GRP) has been well recognized in forest hydrology, especially in dry areas, the processes are not understood because site- or region-specific factors complicate the accurate quantifications. This study integrates meta-analysis and field observation to compare patterns of GRP in forest stands that had different origins (plantations vs. native forests) and tree species (deciduous vs. evergreen) compositions. We aimed at quantifying the dominant biotic and abiotic factors controlling each of the GRP components to form empirical relationships between the GRP components and the influencing factors via the Boosted Regression Trees (BRT) model. We found a convergence in the GRP components among the examined stands that have diverse tree species and origins. Our results indicated that, unlike stem flow (SF) and canopy interception (Ic), the throughfall (TF) did not differ between natural and plantation stands. Meanwhile, from the perspective of species composition, the broadleaf forest stands had significantly higher SF rates than the coniferous stands. We found that stand structures exerted limited influence on TF, but significantly affected SF and Ic. We hypothesized that the residence time of the GRP components was important in explaining the matrix of influencing factors. The cumulative influences of stand structure factors played a more important role than species in most conditions. Based on the most influential factors (cumulative explanatory power > 70 %) selected from the BRT model, we successfully built a general formula to represent the GRP processes across the diverse forest stands in the Loess Plateau. Our study provides insights into the underlying mechanism of GRP for developing more realistic forest hydrological models. An improved understanding of GRP and better models are important for guiding large scale reforestation efforts that account for hydrological processes across stand species and origins.

Quantum effects on dynamic structure factors in dense magnetized plasmas

Quantum effects on dynamic structure factors in dense magnetized plasmas

Ministry of Law and Human Rights Supervision Functions on Notary Organizations

The aim of this research is to analyze the urgency of regulating the supervision of notary organizations by the Ministry of Law and Human Rights and to analyze what factors influence the legal vacuum in the supervision of notary organizations by the Ministry of Law and Human Rights. The legal research method used is normative legal research, the approach used in this research is a statutory approach and a conceptual approach. The legal materials in this research are primary, secondary and tertiary legal materials. The urgency of regulating the supervision of notary organizations by the Ministry of Law and Human Rights is very urgent or important to be promulgated in the form of a Ministerial Regulation as an Implementing Regulation of Article 82 point 5 UUJN Amendment, to obtain legal certainty from the Ministry of Law and Human Rights so as to increase professionalism and quality of work as well as providing legal certainty and protection for clients and the wider community. And the factors that influence the lack of legal supervision of notary organizations by the Ministry of Law and Human Rights are: first, the legal substance factor (Legal Substance), the absence of a Ministerial Regulation as a legal basis for determining, coaching and supervising notary organizations. Second, the legal structure factor (Legal Structure) of Notary Organizations should be established by the Ministry of Law and Human Rights as an institution with authority to develop and supervise notary organizations. However, the absence of a Ministerial Regulation as a legal instrument that regulates the determination, guidance and supervision in accordance with the mandate of Article 82 means that the Ministry of Law and Human Rights does not have the authority to determine, guide and supervise notary organizations. Third, legal culture, this dualism in management shows an unhealthy notary organizational culture.

Institutions, urban space, and residential markets in globalizing Shanghai: A comparative study of housing sale and rental prices

ABSTRACT China’s skyrocketing residential market has raised concerns about housing affordability in metropolitan areas. Current literature usually overlooks the various mechanisms between sale and rent, which may unfold more fundamental structural forces beyond housing location and attributes. This study constructs an analytical framework to investigate how global, regional, and local development contexts, including institutional forces, urban spatial structure, human capital, and neoclassical factors, affect apartment sales and rental prices in Shanghai, China. These factors collectively shape the city’s residential market, but renters and buyers may show different housing preferences. Such variation is highly related to their residential status, as renters may prioritize job opportunities while buyers value service amenities more. From the spatial perspective, suburban areas are more inclusive than urban centers, as globalization and institutional factors have exacerbated inequality in the residential housing market in urban centers, and homeownership is changing the patterns of segregation in Chinese cities.

Identifying the latent relationships between factors associated with traffic crashes through graphical models

Traffic safety field has been oriented toward finding the relationships between crash outcomes and predictor variables to understand crash phenomena and/or predict future crashes. In the literature, the main framework established for this purpose is based on constructing a modelling equation in which crash outcome (e.g., frequencies) is examined in relation to explanatory variables chosen based on the problem at hand. Despite the importance and success of this approach, there are two issues that are generally not discussed: 1) the latent relationships between factors associated with crashes are oftentimes not the focus of analysis or not observed; and 2) there are not many tools to make informed decisions on which variables might have an impact on the crash outcome and should be included in a safety model, particularly when observations are limited. To address these issues, this paper proposes the use of graphical models, namely a Markov random field (MRF) modelling, Bayesian network modelling, and a graphical XGBoost approach, to disclose relationship topologies of explanatory variables leading to fatal and incapacitating injury pedestrian crashes. The application of graph learning models in traffic safety has a high potential because they are not only useful to understand the mechanism behind the crash occurrence but also can assist in devising accurate and reliable prevention measures by identifying the true variable structure and essential factors jointly acting towards crash occurrence, similar to a pathological examination.

Local structure of concentrated NaFSA solutions in propylene carbonate studied by X-ray and neutron diffraction methods

Abstract The microscopic structure of 10 mol% NaFSA [FSA: bis(fluorosulfonyl)amide]-propylene carbonate (PC) solution has been investigated by means of X-ray and neutron diffraction techniques. The solvation structure of Na+ has been determined from least-squares fitting analysis of X-ray intermolecular difference interference terms observed for 10 mol% NaFSA-PC solution and pure liquid PC. In the present solution, onaverage, 6(1) PC molecules are involved in the first solvation shell of Na+ with intermolecular distance rNaO = 2.26(7) Å, and bond angle ∠Na+…O = C = 169(9)°. Intermolecular correlation between neighboring PC molecules in the solution has been derived from simultaneous least-squares fitting analysis of observed H–H, H–X, and X–X (X: atoms except for H) intermolecular partial structure factors determined from neutron diffraction data for H/D isotopically-substituted sample solutions. An indication of anti-parallel configuration of the nearest neighbor PC molecules has been suggested.

Self-Assembly and Antimicrobial Activity of Lipopeptides Containing Lysine-Rich Tripeptides.

The conformation and self-assembly of two pairs of model lipidated tripeptides in aqueous solution are probed using a combination of spectroscopic methods along with cryogenic-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS). The palmitoylated lipopeptides comprise C16-YKK or C16-WKK (with two l-lysine residues) or their respective derivatives containing d-lysine (k), i.e., C16-Ykk and C16-Wkk. All four molecules self-assemble into spherical micelles which show structure factor effects in SAXS profiles due to intermicellar packing in aqueous solution. Consistent with micellar structures, the tripeptides in the coronas have a largely unordered conformation, as probed using spectroscopic methods. The molecules are found to have good cytocompatibility with fibroblasts at sufficiently low concentrations, although some loss of cell viability is noted at the highest concentrations examined (above the critical aggregation concentration of the lipopeptides, determined from fluorescence dye probe measurements). Preliminary tests also showed antimicrobial activity against both Gram-negative and Gram-positive bacteria.

Translation, cross-cultural adaptation and validation of the Arabic multimorbidity treatment burden questionnaire (MTBQ-A): A study of adults with multimorbidity

BackgroundStudies internationally have found that a high treatment burden is associated with several long-term conditions and poor quality of life. ObjectivesTo translate, culturally adapt, and provide evidence of reliability, validity, and factor structure of the Multimorbidity Treatment Burden Questionnaire for use among Arabic-speaking adults with multimorbidity. MethodsStandard guidelines for the cross-cultural adaptation of self-report measures were followed. The original 10-item MTBQ was translated into Arabic by professional translators using forward-backward translation. An expert group, including the creator of the MTBQ, participated in the cultural adaptation and content validity, followed by cognitive interviewing and pilot testing. The questionnaire was then tested on 177 Arabic-speaking patients with multimorbidity recruited from community pharmacies in the United Arab Emirates. The distribution of responses, dimensionality, internal consistency reliability, and construct validity were examined. ResultsThe content validity of the MTBQ-A was good (Content Validity Index = 0.94), and cognitive interviews found that the items were well understood. The scale showed positive skewness and high floor effects. Factor analysis supported a two-dimensional structure (factor loadings >0.4): factor one was named “Self-management and social support,” and factor two was named “Burden of visiting health care services and health care professionals”. The questionnaire had good internal consistency (α = 0.83). As predicted, a higher MTBQ score in both factors was associated with poor health-related quality of life in all dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression (p values < 0.05); and negatively correlated with self-efficacy in taking medication (p < 0.01) and in learning about medication (p < 0.01). ConclusionsThe Arabic MTBQ is a valid and reliable measure of treatment burden with good construct validity and internal consistency. This easy-to-understand questionnaire can be used to assess the perceived treatment burden among Arabic-speaking patients with multimorbidity.