bluuebunny/crossref_metadata_2025 huggingface dataset:
Lightweight environment sensing algorithm for intelligent driving based on improved YOLOv7
Authors: Qian Guoyong , Xie Dongbo , Bi Dawei , Wang Qi , Chen Liqing , Wang Hai
Published: June 2024

Accurately and quickly detecting obstacles ahead is a prerequisite for intelligent driving. The combined detection scheme of light detection and ranging (LiDAR) and the camera is far more capable of coping with complex road conditions than a single sensor. However, immediately afterward, ensuring the real‐time performance of the sensing algorithms through a significantly increased amount of computation has become a new challenge. For this purpose, the paper introduces an improved dynamic obstacle detection algorithm based on YOLOv7 (You Only Look Once version 7) to overcome the drawbacks of slow and unstable detection of traditional methods. Concretely, Mobilenetv3 supplants the backbone network utilized in the original YOLOv7 architecture, thereby achieving a reduction in computational overhead. It integrates a specialized layer for the detection of small‐scale targets and incorporates a convolutional block attention module to enhance detection efficacy for diminutive obstacles. Furthermore, the framework adopts the Efficient Intersection over Union Loss function, which is specifically designed to mitigate the issue of mutual occlusion among detected objects. On a dataset consisting of 27,362 labelled KITTI data samples, the improved YOLOv7 algorithm achieves 92.6% mean average precision and 82 frames per second, which reduces the Model_size by 85.9% and loses only 1.5% accuracy compared with the traditional YOLOv7 algorithm. In addition, this paper builds a virtual scene to test the improved algorithm and fuses LiDAR and camera data. Experimental results conducted on a test vehicle equipped with a camera and LiDAR sensor demonstrate the effectiveness and significant performance of the method. The improved obstacle detection algorithm proposed in this research can significantly reduce the computational cost of the environment perception task, meet the requirements of real‐world applications, and is crucial for achieving safer and smarter driving.
Research and design of image style transfer technology based on multi‐scale convolutional neural network feature fusion
Authors: Liang Yongzhen , Lin Feng , Xie Wensheng , Wang Jinzhong , Nie Tian
Published: June 2024

To reduce the occurrence of information loss and distortion in image style transfer, a method is proposed for researching and designing image style transfer technology based on multi‐scale convolutional neural networks (CNNs) feature fusion. Initially, the VGG19 model is designed for coarse and fine‐scale networks to achieve multi‐scale CNN feature extraction of target image information. Subsequently, while setting the corresponding feature loss function, an additional least‐squares penalty parameter is introduced to balance the optimal total loss function. Finally, leveraging the characteristics of stochastic gradient descent iteration, image features are fused and reconstructed to obtain better style transfer images. Experimental evaluations utilize peak signal‐to‐noise ratio (PSNR), structural similarity index (SSIM), information entropy (IE), and mean squared error (MSE) as metrics for assessing the transferred images, comparing them with three typical image style transfer methods. Results demonstrate that the proposed method achieves optimal performance across all metrics, realizing superior image style transfer effects.
The impact of environment on size: Galaxies are 50% smaller in the Fornax Cluster compared to the field
Authors: Chamba Nushkia , Hayes Matthew J. ,   The LSST Dark Energy Science Collaboration
Published: June 2024

Size is a fundamental parameter for measuring the growth of galaxies and the role of the environment on their evolution. However, the conventional size definitions used for this purpose are often biased and miss the diffuse, outermost signatures of galaxy growth, including star formation and gas accretion. We address this issue by examining low surface brightness truncations or galaxy ‘edges’ as a physically motivated tracer of size based on star formation thresholds. Our total sample consists of ∼900 galaxies with stellar masses ranging from 105 M⊙ < M⋆ < 1011 M⊙. This sample of nearby cluster, group satellite, and nearly isolated field galaxies was compiled using multi-band imaging from the Fornax Deep Survey, deep IAC Stripe 82, and Dark Energy Camera Legacy Surveys. We find that the edge radii scale as Redge ∝ M⋆0.42, with a very small intrinsic scatter (∼0.07 dex). The scatter is driven by the morphology and environment of galaxies. In both the cluster and field, early-type dwarfs are systematically smaller by approximately 20% compared to late-type dwarfs. However, galaxies in the Fornax cluster are the most impacted. At a fixed stellar mass, edges in the cluster can be found at about 50% smaller radii, and the average stellar surface density at the edges is a factor of two higher, ∼1 M⊙/pc2. Our findings support the rapid removal of loosely bound neutral hydrogen (H I) in hot, crowded environments, which truncates galaxies outside-in earlier, preventing the formation of more extended sizes and lower density edges. Our results highlight the importance of deep imaging surveys to the study of low surface brightness imprints of the large-scale structure and environment on galaxy evolution.
New polarimetric study of the galactic X-ray burster GX 13+1
Authors: Bobrikova Anna , Di Marco Alessandro , La Monaca Fabio , Poutanen Juri , Forsblom Sofia V. , Loktev Vladislav
Published: June 2024

Weakly magnetized neutron stars (WMNSs) are complex astrophysical objects with challenging phenomenology. For decades, they have been studied via spectrometry and timing analyses. It is well established that the spectrum of WMNSs consists of several components traditionally associated with the accretion disk, the boundary or spreading layer, and the wind, along with their interactions. Since 2022, WMNSs have been actively observed using the Imaging X-ray Polarimetry Explorer (IXPE). Polarimetric studies have provided new information about the behavior and geometry of these sources. One of the most enigmatic sources in this category, the galactic X-ray burster GX 13+1, was first observed with IXPE in October 2023. A highly variable polarization at levels of 2–5% was detected, with the source showing a rotation of the polarization angle (PA), suggestive of misalignment within the system. A second observation was performed in February 2024, complemented by observations from Swift/XRT. IXPE measured an overall polarization degree (PD) of 2.5% and a PA of 24°, while Swift/XRT data helped us evaluate the galactic absorption and fit the continuum. Here, we study the similarities and differences in the polarimetric properties of the source during the two observations. Our findings confirm the expected misalignment in the system and the assignment of the harder component to the boundary layer. We also emphasize the significance of the wind in the system. Additionally, we observe notable differences in the variation of polarimetric properties with energy and over time.
Parameters and resource potential of the territory of populated places in the zone of influence of stopping points
Authors: Kulichenko Nataliia , Savytskyi Mykola , Tovbych Valery
Published: June 2024

The authors did not set a goal to make a comprehensive analysis of all aspects of the formation and functioning of the settlement territories in the zone of stopping points influence.The article is a review and a problem. It provides an overview and analysis of research directly or indirectly related to the problem under consideration. The results of multivariate calculations using the regulatory documents of Ukraine are presented: parameters of the zones of transport lines and stopping points influence (width of the zones of influence, total area of construction and area of residential construction in the zone of influence of one stopping point), resource potential (housing stock, population) for the largest, large, large and small settlements and their zones (central, middle, peripheral). The performed calculations show that the territories of settlements in the zone of influence of stopping points occupy an important place in the planning structure and vital activities of settlements due to their significant resource potential − territory, population, housing stock, as well as the close relationship of their structural parameters with the parameters of the transport infrastructure. which indicates the need to consider them as a whole.
Modeling ship-wind turbine dynamics for optimal energy generation and navigation
Authors: Melnyk Oleksiy , Onyshchenko Svitlana , Kuznichenko Serhii , Sudnyk Nadiia , Nykytyuk Petro
Published: June 2024

This paper deals with modeling the dynamics of the ship-wind turbine system in order to optimize power generation and ensure safe navigation. The focus is on developing mathematical models describing the interaction of wind forces, turbine performance and ship dynamics. Numerical simulations are used to investigate the effects of varying wind conditions, turbine design and navigation parameters on energy efficiency. Control strategies are also developed to maximize the energy output of wind turbines while maintaining stability and safety of ship navigation. Model validation is performed through comparative analysis with experimental data or cases from existing wind-assisted ship propulsion systems. The aim of the study is to provide valuable practical recommendations for the implementation of wind energy technologies in maritime operations, contributing to sustainable development and environmental standards in shipping.
Air Quality in Fitness Centers: Status and Improvement Strategies
Authors: Li Guozhu , Luo Bin , Liu Maolin , Xue Haizhu , Tian Yongzhen , Meng Chong , Xie Linna
Published: June 2024

As a place where people do physical activity for health, the indoor air quality of fitness center has a significant impact on human health. To systematically understand the current state of indoor air quality in fitness centers, this study reviews recent literature on the indoor environment of fitness centers, analyzes factors that affect air quality, and proposes a series of technical strategies to improve it. The analysis reveals: 1) Significant pollution issues with the indoor air quality in fitness centers; 2) Notable variations in air quality across different functional areas and time periods; 3) Air quality can be improved by adopting appropriate technical measures. This paper recommends that future air quality management strategies should consider factors such as the intensity of physical activity and crowd density to develop ventilation strategies, aiming for targeted air quality management that varies by area and time.
Comprehensive evaluation of green development level of agriculture in Guiyang
Authors: Ma Bingnan , Hou Shuangshuang
Published: June 2024

Green agriculture is a new mode of modern agricultural development, and measuring the green agricultural development level appropriately can provide some reference for the realization of agricultural modernization in Guiyang City. The estimate index system of the green agricultural development level in Guiyang City was established and using analytic hierarchy process (AHP), the index of green agricultural development leve was calculated. The results show that the green level of production process was highest with the weight value of 0.633, and the weight value of green level of agricultural economy was lower, which was only 0.107. The overall green agricultural development level in Guiyang City was 0.259, showing a low green agricultural development level. Therefore, it has occasion to further reform the factors affecting the green agricultural development.
Urban Resilience through Green Roofing: A Literature Review on Dual Environmental Benefits
Authors: Zhang Xingyu , Soe Aung Naing , Dong Sihui , Chen Minghao , Wu Mengzhen , Htwe Thet
Published: June 2024

Urban areas face significant environmental challenges, notably rainwater management and the urban heat island effect. As sustainable ecological infrastructures, Green roofs provide dual benefits in addressing these issues. The literature review thoroughly explores how effective green roofs are at boosting urban resilience by mitigating Urban Heat Island effects and enhancing stormwater control. Findings across various studies indicate that green roofs could significantly reduce surface and ambient temperatures, with some studies reporting surface temperature reductions of up to 30 °C. Additionally, green roofs contribute to stormwater management by retaining at lseast 51% of annual rainfall, thereby reducing runoff volume and peak flow rates. By synthesizing data from 28 case studies worldwide, this review highlights the substantial environmental benefits green roofs offer in urban settings. Our analysis suggests that broader implementation and further research into green roof technologies are essential for sustainable urban development. This paper calls for increased integration of green roofs into urban planning to leverage their environmental benefits, particularly in mitigating climate change impacts and enhancing urban ecological systems.
Pouring Vitality and Reconstructing Memory：Baosteel Industrial Heritage Landscape Renovation Design Study
Authors: Zhao Ruoyu
Published: June 2024

[Objective]Taking the brownfield of Baosteel industrial site as an example, this study proposes a landscape renovation program based on the theoretical foundation of ecological restoration in response to the problems of soil destruction, water pollution, landscape fragmentation, and loss of field area memory. [Objective]Combine history and culture with ecological restoration in order to preserve special historical relics, so as to promote the reconstruction of the land ecosystem in the factory area and improve the utilization rate of the land in the field area. [Methods] 1. Soil was sampled by five-point sampling method to assess the degree and distribution of soil pollution. 2. Elemental content testing was carried out for Baosteel FGD wastewater. 3. Industrial landscape renovation cases were analyzed. 4. Landscape remediation measures at three levels: space, historical value of the plant, and biological level are proposed according to the soil and water conditions. [Conclusion] It will provide some references and lessons for industrial brownfield renovation, and help to improve the ecological quality and recreational value of brownfield sites of Baosteel industrial sites with multiple measures.
Factors influencing residents’ waste management behavior: A case study in Beijing, China
Authors: Xu Mengmeng , Liu Pingping
Published: June 2024

With the continuous increase of the total amount of municipal solid waste in China, waste management has become an urgent matter. To address this challenge, the Chinese government recently launched a new waste management system. Previous studies have confirmed the effectiveness of incorporating intrinsic motivation factor into the theory of planned behavior for predicting green behavior, however, the interaction between variables in the model has not been fully explored in the Chinese context. Therefore, this study extended the theory of planned behavior with moral norms to evaluate the household waste management behavior of Beijing residents. With 342 residents as samples, hierarchical multiple regression was used for analysis. The empirical result showed that all determinants in the extended model positively predict behaviors. Moral norms were the most important determinants of behavior, followed by subjective norms, and then perceived behavioral control and attitude. In addition, moral norms played a mediating role in the influence of attitudes and subjective norms on behavior. These findings will help expand and improve understanding of the key factors affecting residential waste management, make reasonable recommendations for environmental protection and sustainable development.
Study on adhesion mechanism of fouling organisms on marine steel surface based on inverted microscope
Authors: Shen Kai , Li Yi , Wu Xia , Jung Hyun-Do , Li Weirong , Liu Zhihui , Zafariddin Nuriddinov Khusniddin , Mashrukovna Abdujabbarova Umida , Li Yanfang , Lv Zhaoyang , Giyasov Shukhrat , Tie Di
Published: June 2024

Marine stainless steel is immersed in seawater for a long time, and its surface will inevitably adhere layer by layer to form biofilm, which will lead to microbial corrosion of the material. Therefore, it is necessary to master the microbial adhesion mechanism to better control the occurrence of fouling. However, at present, the observation method is to dye by fluorescence microscope or fix the fouling organisms and then observe them by scanning electron microscope (SEM). These methods all damage the cell activity of algae, and only the results of algae attachment can be observed, which is not conducive to further study of algae attachment mechanism. Based on the inverted microscope platform, the observation of algae attached to the metal surface found that the thinner the substrate of the sample liquid, the clearer the image of algae attached to the metal surface, and further found that the dominant algae in the liquid could complete the attachment and aggregation behavior on the metal surface within 1 hour to 2 hours. The conclusions obtained in this paper will guide the study on the attachment mechanism of fouling organisms on metal surfaces and provide a preliminary basis for the design of prevention and control strategies and time points of fouling organisms.
Analysis on environmental monitoring of persistent organic pollutants
Authors: Li Kai
Published: June 2024

Persistent organic pollutants will cause harm to living organisms and the environment, so it is necessary to strengthen environmental monitoring, find pollutants in time and take effective measures to control them. This paper analyzes the characteristics of persistent pollutants, from the water, atmosphere, soil these dimension analysis of environmental monitoring, and put forward the corresponding Suggestions, including improve the environmental monitoring system, the advanced monitoring system and detection methods,reasonable layout of monitoring points, intensify environmental protection propaganda, grasp the influence of pollutants, transmission law, etc., to provide reference for pollution control.
Analysis of concentrations of nitrate salts of PM2.5 in downwind marine atmospheres related to gas-particle partitioning and different sources in China
Authors: Zhang Qian , Yao Xiaohong
Published: June 2024

In order to explore the concentration characteristics and sources of major inorganic ions in marine atmospheric PM2.5, this study explores the concentration features of major inorganic ions in PM2.5 under the marine atmospheric observations of the offshore ~2000 km coastline of China in the downwind direction of the land-based sources. The observation results showed that the concentration of NO3- ranged from 0.03-10 μg m-3 with a variation of three orders of magnitude, and the main contributing species in PM2.5 was NO3- in the high concentration level observation period. The E-AIM results showed that NH3, HNO3 did not reach thermodynamic equilibrium with NH4+, NO3-, and ammonium nitrate was in volatile state, both during the day and at night. The results of the source analysis using PMF showed that there were three factors with identifiable contributions to NO3-, with Factor 1 considered to be a source of ship emissions, Factor 2 reflecting aerosols under low and medium pollution scenarios, and Factor 3 being aerosols under heavy pollution scenarios. Factor 3 was the main contributing source of NO3- concentration with a contribution of 84%, followed by Factor 2 (contribution of 15%) and the lowest contribution by Factor 1 (0.7%).
Analysis of viral aerosol distribution characteristics in typical body positions of patients under local exhaust air
Authors: Li Xulin , Wu Qiang , Zhang Endi , Wu Yuhao
Published: June 2024

In this paper, CFD numerical simulation and experiment were used to simulate the diffusion process of human exhaled aerosol particles, and the influence of human lying down, sitting and standing posture on the diffusion of aerosol particles under local exhaust air conditions was studied. The results show that different body positions have significant effects on local exhaust air effect. Only 13.2% of the aerosol particles could be removed by local exhaust air in the lying state. The exclusion rate in sitting posture was 25.4%; The exclusion rate for standing posture was 20.6%. Local exhaust air alone is not enough to prevent infection. It is recommended to adopt the combination of mixed ventilation and local exhaust air, which may have a better effect on preventing cross infection, indoor particulate matter transmission and controlling pollution.
Insights into the efficient degradation of metformin - An emerging antidiabetic medicine by UV/Sulfite process
Authors: Gu Yurong , Liu Xiaoming , Han Qi , Wang Feng
Published: June 2024

The growing utilization of metformin (MET) in diabetes treatment has resulted in its occurrence in wastewater treatment plants, where conventional techniques were proved inadequate in eliminating it. The present study evaluated the potential of UV/sulfite system in degrading MET and analyzed the influence of common factors (i.e UV intensity, dosage of reagent, the pH value of reaction solution) on the target contaminant removal. In comparison with both direct UV photolysis and merely sulfite reduction, the UV/sulfite process had a remarkable enhancement in MET removal, with 96.54% of MET (initial concentration of 15 mg/L) being degraded within 30 minutes. A strong linear relationship (R2 > 0.99) was observed between MET degradation kinetics and UV intensity. The increase of sulfite dosage and solution pH could promote MET degradation to a certain extent in the studied system. Additionally, the hydrated electron (eaq-) was found played the principle role in MET removal through scavenging reactions.
Distribution of magnetic susceptibility of surface dust in Xining City and its indicative significance to heavy metal pollution
Authors: Zhang Qi , Chongyi E , Xian Baji , Peng Qiang , Zhang Zhaokang , Zhang Shuaiqi
Published: June 2024

The establishment of heavy metal pollution grade standards based on the magnetic susceptibility of surface dust can provide a simpler magnetic method for the evaluation of heavy metal pollution of surface dust. A total of 251 urban soil surface samples were collected in Xining City, and As, Cd, Cr, Cu, Ni, and Pb were determined V and Zn contents, as well as low-frequency magnetic susceptibility (χLF) and high-frequency magnetic susceptibility (χHF). The common Kriging interpolation method was used to explore the spatial distribution of χLF, and the pollution load index (PLI) was used to evaluate the degree of soil heavy metal pollution, and the correlation analysis between PLI and χLF was established。 The results showed that the average PLI of the seven heavy metals in the urban soil samples of Xining City was 2 34. Moderate pollution, Zn is the most important pollution factor. The average value of soil χLF was 125. 7 × 10-8m3 kg-1, which decreased from “northwest-southeast”, and the high-value area appeared in the northwest near Xining Special Steel along the line. The regression equation between soil heavy metal PLI and χLF was y=3.36E-06x2+0.01x+0.9092, showing a significant positive correlation (p<0.01). The χLF of surface dust can be used to evaluate the degree of heavy metal pollution of surface dust in Xining City: when the χLF of surface dust is ≤66.05 × 10-8m3 kg-1, it is pollution-free; When 66.05 × 10-8m3 kg-1<χLF≤437.332 × 10-8m3 kg-1, it is slightly polluted. When 437.332 × 10-8m3 kg-1<χLF≤652.02 × 10-8m3 kg-1, it is moderately polluted. When χLF > 652.02 × 10-8m3 kg-1, it is an intensity pollution.
Dossier : « La recherche au défi de la crise des temporalités » : Les temps de l’environnement, d’une construction interdisciplinaire commune à la crise des temporalités
Authors: Sajaloli Bertrand , Dournel Sylvain , Lespez Laurent , Luglia Rémi , Valette Philippe , Beck Corinne , Marinval Marie-Christine
Published: June 2024

La réflexion sur les temporalités des liens nature-société a occasionné de riches travaux au sein des différentes disciplines des sciences humaines et sociales (SHS) dès les années 1970. En dressant une historiographie des temps de la nature dans les SHS, en insistant sur les controverses et sur les résultats conceptuels (anthroposystème, héritage, crise, résilience…) de cette historiographie, c’est une épistémologie du temps qui apparaît, scandée en trois étapes : la construction interdisciplinaire des temps de l’environnement, la crise opérationnelle des temporalités pour lesquelles le rapport au vivant constitue un creuset d’engagement, enfin l’affirmation de la contribution des sciences géohistoriques à la gouvernance de l’environnement.
Apport de l’intelligence artificielle dans la prévision de croissance mandibulaire : revue systématique de la littérature
Authors: Brouchet Edouard , de Brondeau François , Boileau Marie-José , Makaremi Masrour
Published: June 2024

L’orthodontiste intervient principalement auprès d’enfants en cours de croissance. L’examen clinique initial ne fournit qu’une image statique qui doit être interprétée en tenant compte de son évolution potentielle. Une prédiction précise de la croissance mandibulaire, permettrait au praticien d’améliorer le diagnostic, la planification du traitement et ainsi la prise en charge du patient.

De nombreux travaux de recherche ont été menés, basés sur des signes structuraux, des analyses céphalométriques et des valeurs d’agrandissement moyen, mais restent imprécis. Les limites rapportées comprennent principalement une variabilité interindividuelle extrême, des schémas de croissance variables selon l’âge, un manque de signes structuraux caractéristiques avant la puberté, l’utilisation de normes statistiques et de résultats dépendant directement de l’expérience du clinicien. À ce jour, il n’existe aucun consensus sur la meilleure méthode pour prédire la croissance mandibulaire, et l’orthodontiste ne peut se fier uniquement à son intuition d’expert.

Ces dernières années, la combinaison de l’intelligence artificielle (IA) et des sciences cognitives dans le domaine médical a révolutionné l’interprétation des radiographies. Les techniques d’apprentissage automatique (ML) et profond (DL) représentent une approche novatrice grâce à leur capacité à analyser d’énormes volumes de données tout en éliminant les biais humains.

L’objectif de cette revue systématique était d’examiner les différents résultats des prévisions de croissance mandibulaire par intelligence artificielle chez des patients en cours de croissance. Ces résultats suggèrent que nous ne sommes encore qu’aux débuts de l’orthodontie tirant parti du diagnostic et de la prise de décision de l’IA, mais ces modèles de prévision de croissance devraient devenir, dans un avenir proche, des systèmes de support clinique fiables pour les orthodontistes.
The photodissociation dynamics and ultrafast electron diffraction image of cyclobutanone from the surface hopping dynamics simulation
Authors: Peng Jiawei , Liu Hong , Lan Zhenggang
Published: June 2024

The comprehension of nonadiabatic dynamics in polyatomic systems relies heavily on the simultaneous advancements in theoretical and experimental domains. The gas-phase ultrafast electron diffraction (UED) technique has attracted significant attention as a unique tool for monitoring photochemical and photophysical processes at the all-atomic level with high temporal and spatial resolutions. In this work, we simulate the UED spectra of cyclobutanone using the trajectory surface hopping method at the extended multi-state complete active space second order perturbation theory (XMS-CASPT2) level and thereby predict the results of the upcoming UED experiments in the Stanford Linear Accelerator Laboratory. The simulated results demonstrate that a few pathways, including the C2 and C3 dissociation channels, as well as the ring opening channel, play important roles in the nonadiabatic reactions of cyclobutanone. We demonstrate that the simulated UED signal can be directly interpreted in terms of atomic motions, which provides a unique way of monitoring the evolution of the molecular structure in real time. Our work not only provides numerical data that help to determine the accuracy of the well-known surface hopping dynamics at the high XMS-CASPT2 electronic-structure level but also facilitates the understanding of the microscopic mechanisms of the photoinduced reactions in cyclobutanone.
Contributions beyond direct random-phase approximation in the binding energy of solid ethane, ethylene, and acetylene
Authors: Pham Khanh Ngoc , Modrzejewski Marcin , Klimeš Jiří
Published: June 2024

The random-phase approximation (RPA) includes a subset of higher than second-order correlation-energy contributions, but stays in the same complexity class as the second-order Møller–Plesset perturbation theory (MP2) in both Gaussian-orbital and plane-wave codes. This makes RPA a promising ab initio electronic structure approach for the binding energies of molecular crystals. Still, some issues stand out in practical applications of RPA. Notably, compact clusters of nonpolar molecules are poorly described, and the interaction energies strongly depend on the reference single-determinant state. Using the many-body expansion of the binding energy of a crystal, we investigate those issues and the effect of beyond-RPA corrections. We find the beneficial effect of quartic-scaling exchange and non-ring coupled-cluster doubles corrections. The nonadditive interactions in compact trimers of molecules are improved by using the self-consistent Hartree–Fock orbitals instead of the usual Kohn–Sham states, but this kind of orbital input also leads to underestimated dimer energies. Overall, a substantial improvement over the RPA with a renormalized singles approach is possible at a modest quartic-scaling cost, which encourages further research into additional RPA corrections.
Photoabsorption cross section measurements of acetylene in the nonionizing region using the double-ion chamber method
Authors: Kim Hyun
Published: June 2024

The double-ion chamber (DIC) method has been used to measure photoabsorption cross sections in the ionization region of the sample gas. In this study, we introduce a method to extend the wavelength region of the DIC measurements beyond the ionization threshold wavelength by using the photoion currents from the impurities in the sample gas. To verify this method, the photoabsorption cross sections of C2H2 (ionization threshold wavelength λth = 108.8 nm) have been measured from 105 to 137 nm. The natural impurity, acetone (λth = 127.8 nm), contained 1% in high-purity grade acetylene (C2H2) sample gas, allowing for measurements in the non-ionizing region of C2H2 up to 127.7 nm. By adding 1% benzene (λth = 134.6 nm) in the sample gas, measurements were possible even further, to 134.5 nm. This new method enables the measurement of the photoabsorption cross section by photoions that are produced from the impurities in the sample gas in a substantial amount. The current measurement methodology aligns well with the previous measurements of Suto and Lee [Suto and Lee, J. Chem. Phys. 80, 4824 (1984)].
Isotopic effects on the rotational (de-)excitation rate coefficients of ortho-CH3Cl colliding with He
Authors: Ajili Yosra , Ben Abdallah Driss , Hochlaf Majdi
Published: June 2024

Chloromethane, CH3Cl, is the first organohalogen molecule to be detected in the interstellar medium. Using the recently generated accurate three-dimensional potential energy surface (3D-PES) for the weakly bound CH335Cl–He complex, we deduced that of CH337Cl–He. Both 3D-PESs were incorporated later into dynamical computations code for nuclear motions treatments of each isotopologue colliding with He. We determined the state-to-state (de-)excitation cross sections for transitions among the 105 lowest rotational levels of both ortho-CH335Cl and ortho-CH337Cl (up to jkɛ = 206±). For total energies up to 100 cm−1, we used the quantum close-coupling methodology, and we adopted the coupled state approach for higher energies (up to 2500 cm−1). Rate coefficients for temperatures ranging from 5 to 150 K are then deduced after averaging these cross sections over a Maxwell–Boltzmann velocity distribution. Computations show that isotopic effects are weak, validating the use of collision rates of ortho-CH335Cl for ortho-CH337Cl and vice-versa. However, we expect that our results will be helpful to accurately determine the abundances of these isotopologues in the interstellar medium and, more generally, for understanding the complex and still not fully elucidated chemistry of chlorine containing molecular species there.
Relativistic Douglas–Kroll–Hess calculations of hyperfine interactions within first-principles multireference methods
Authors: Wysocki Aleksander L. , Park Kyungwha
Published: June 2024

A relativistic magnetic hyperfine interaction Hamiltonian based on the Douglas–Kroll–Hess (DKH) theory up to the second order is implemented within the ab initio multireference methods, including spin–orbit coupling in the Molcas/OpenMolcas package. This implementation is applied to calculate relativistic hyperfine coupling (HFC) parameters for atomic systems and diatomic radicals with valence s or d orbitals by systematically varying active space size in the restricted active space self-consistent field formalism with restricted active space state interaction for spin–orbit coupling. The DKH relativistic treatment of the hyperfine interaction reduces the Fermi contact contribution to the HFC due to the presence of kinetic factors that regularize the singularity of the Dirac delta function in the nonrelativistic Fermi contact operator. This effect is more prominent for heavier nuclei. As the active space size increases, the relativistic correction of the Fermi contact contribution converges well to the experimental data for light and moderately heavy nuclei. The relativistic correction, however, does not significantly affect the spin-dipole contribution to the hyperfine interaction. In addition to the atomic and molecular systems, the implementation is applied to calculate the relativistic HFC parameters for large trivalent and divalent Tb-based single-molecule magnets (SMMs), such as Tb(III)Pc2 and Tb(II)(CpiPr5)2 without ligand truncation using well-converged basis sets. In particular, for the divalent SMM, which has an unpaired valence 6s/5d hybrid orbital, the relativistic treatment of HFC is crucial for a proper description of the Fermi contact contribution. Even with the relativistic hyperfine Hamiltonian, the divalent SMM is shown to exhibit strong tunability of HFC via an external electric field (i.e., strong hyperfine Stark effect).
Direct measurement of tensile mechanical properties of few-layer hexagonal boron nitride (h-BN)
Authors: Zhou Jingzhuo , Zhu Mengya , Han Ying , Zhou Xuefeng , Wang Shanmin , Chen Juzheng , Wu Hao , Hou Yuan , Lu Yang
Published: June 2024

Hexagonal boron nitride (h-BN) has excellent thermal conductivity and dielectric properties, which shows great potential for low-dimensional devices. However, mechanical properties of h-BN have not been comprehensively investigated through experiments. In this work, we conduct in situ direct tensile tests on freestanding single-crystal few-layer h-BN nanosheets with various layer numbers from 3 to 8, with an elaborate sample transfer and characterization protocol. Young's modulus of 573.8 ± 101.4 GPa and a tensile fracture strain up to 3.2% are revealed, which are comparable to its monolayer counterpart. Moreover, we find a tough-to-brittle transition in few-layer h-BN with the increase in layer number, which is attributed the interplay between the van der Waals interaction and in-plane covalent bonding. These findings could open up new possibilities in mechanical research of van der Waals materials and provide guidance for the design of h-BN-based devices and composites.
Glassy dynamics in a liquid of anisotropic molecules: Bifurcation of relaxation spectrum
Authors: Kumar Shubham , Sarkar Sarmistha , Bagchi Biman
Published: June 2024

In experimental and theoretical studies of glass transition phenomena, one often finds a sharp crossover in dynamical properties at a temperature Tcr. A bifurcation of a relaxation spectrum is also observed at a temperature TB≈Tcr; both lie significantly above the glass transition temperature. In order to better understand these phenomena, we introduce a new model of glass-forming liquids, a binary mixture of prolate and oblate ellipsoids. This model system exhibits sharp thermodynamic and dynamic anomalies, such as the specific heat jump during heating and a sharp variation in the thermal expansion coefficient around a temperature identified as the glass transition temperature, Tg. The same temperature is obtained from the fit of the calculated relaxation times to the Vogel–Fulcher–Tammann (VFT) form. As the temperature is lowered, the calculated single peak rotational relaxation spectrum splits into two peaks at TB above the estimated Tg. Similar bifurcation is also observed in the distribution of short-to-intermediate time translational diffusion. Interrogation of the two peaks reveals a lower extent of dynamic heterogeneity in the population of the faster mode. We observe an unexpected appearance of a sharp peak in the product of rotational relaxation time τ2 and diffusion constant D at a temperature Tcr, close to TB, but above the glass transition temperature. Additionally, we coarse-grain the system into cubic boxes, each containing, on average, ∼62 particles, to study the average dynamical properties. Clear evidence of large-scale sudden changes in the diffusion coefficient and rotational correlation time signals first-order transitions between low and high-mobility domains.
Nationwide law enforcement impact on the pet bird trade in China
Authors: Liang Zhijian , Hu Sifan , Zhong Jia , Wei Qian , Ruan Xiangdong , Zhang Li , Lee Tien Ming , Liu Yang
Published: June 2024

Conservation enforcement is a direct strategy to combat illegal wildlife trade in open markets. Yet, its large-scale effectiveness has not been widely assessed due to the lack of extensive market data. Between August 2016 and June 2017, a national coordinated enforcement campaign led by the leading Chinese authority to combat illegal migratory bird trade coincided with the largest-ever pet bird market survey across China by voluntary birdwatchers before and after the enforcement, which served as a unique natural experiment. Across 73 markets from 22 Chinese provinces, the dataset contains 140,723 birds of 346 species from 48 families and recorded a drastic decline in bird abundance traded after enforcement. Notably, species protected under China's Wildlife Protection Law declined significantly, while commercially bred species increased, although responses to enforcement were spatially heterogeneous. Our model showed that the national protection level was the best predictor for the trend of traded species, even after accounting for confounding factors such as regional baseline enforcement pressure and wild native bird populations. However, the widely traded native songbirds were not offered adequate national protection. Future policies should consider the pet bird trade patterns, target key areas of trade, and develop a more systematic market survey design to monitor trade.
Intrinsic-strain-induced ferroelectric order and ultrafine nanodomains in SrTiO
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Authors: Zhang Peixi , Li Qiang , Li Zhiguo , Shi Xiaoming , Wang Haoyu , Huo Chuanrui , Zhou Lihui , Kuang Xiaojun , Lin Kun , Cao Yili , Deng Jinxia , Yu Chengyi , Chen Xin , Miao Jun , Xing Xianran
Published: June 2024

Nano ferroelectrics holds the potential application promise in information storage, electro-mechanical transformation, and novel catalysts but encounters a huge challenge of size limitation and manufacture complexity on the creation of long-range ferroelectric ordering. Herein, as an incipient ferroelectric, nanosized SrTiO
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was indued with polarized ordering at room temperature from the nonpolar cubic structure, driven by the intrinsic three-dimensional (3D) tensile strain. The ferroelectric behavior can be confirmed by piezoelectric force microscopy and the ferroelectric TO1 soft mode was verified with the temperature stability to 500 K. Its structural origin comes from the off-center shift of Ti atom to oxygen octahedron and forms the ultrafine head-to-tail connected 90° nanodomains about 2 to 3 nm, resulting in an overall spontaneous polarization toward the short edges of nanoparticles. According to the density functional theory calculations and phase-field simulations, the 3D strain-related dipole displacement transformed from [001] to [111] and segmentation effect on the ferroelectric domain were further proved. The topological ferroelectric order induced by intrinsic 3D tensile strain shows a unique approach to get over the nanosized limitation in nanodevices and construct the strong strain-polarization coupling, paving the way for the design of high-performance and free-assembled ferroelectric devices.
Chapter 2. Italy
Authors: Bisanti Armando
Published: June 2024

This chapter traces a synthetic picture of Latin literature in Italy between the fifth and fourteenth centuries in its relations with political and cultural history. Generally speaking, the development of medieval Latin literature in Italy is examined with reference to literary genres and geographical areas, with particular attention to auctores and their works. Among the most significant authors are Boethius, Cassiodorus, Venantius Fortunatus, Gregory the Great, Paul the Deacon, Liutprand of Cremona, Peter of Eboli, Salimbene, Iacopo da Varazze, Dante, Petrarch and Boccaccio.
Chapter 3. France et Belgique
Authors: Giraud Cédric
Published: June 2024

This chapter takes a chronological journey through the history of medieval Latin in France, focusing on the great Renaissance periods of the ninth and twelfth centuries. Particular emphasis is placed on the role of educational institutions in fostering the growth of intellectual life and, by extension, literary culture. The end of the Middle Ages is not neglected because, despite the undeniable rise of French in the thirteenth-fourteenth centuries, Latin retained its traditional place at the top of the language ladder and consolidated its role as the language of national and international scholarly communication.
Chapter 4. Germany and Austria
Authors: Mairhofer Daniela
Published: June 2024

This chapter deals with the Medieval Latin language and literature in modern-day Germany and Austria. The first part focuses on the development of the Latin language and literature in those places, while the second part offers a survey of texts relevant from a literary and cultural perspective, which are arranged by genre and discussed in the context of Medieval Latin literary history more generally.
Chapter 5. Switzerland
Authors: Stotz Peter
Published: June 2024

The territory now known as Switzerland was a contact zone for a range of ethnicities, linguistic areas and literary influences. There was no such thing as a specifically Swiss literary landscape in the Latin Middle Ages. Nor did the first beginnings of the formation of a state come into view until the late Middle Ages. In the western areas, significant influence from Gaul/France can be detected. The south-east belongs to the Rhaeto-Romance cultural area. In the east, settled by the Alemanni, the environs of Lake Constance, with the abbeys of St. Gall and Reichenau, were highly productive. Basel was oriented towards the north and the Upper Rhine. Literature was first produced in monasteries and bishoprics, later increasingly in towns. The most popular genres were hagiography and regional historiography, followed by spiritual poetry, theological and profane literature, and didactic poetry.
Chapter 7. Portugal (950–1400)
Authors: Alberto Paulo Farmhouse
Published: June 2024

This brief overview of the literary production of medieval Portugal shows the paths of continuity and communication with the production of other territories in the Iberian Peninsula and beyond into medieval Europe. The same genres and topics, the same anxieties and expectations, were dealt with by scholars from similar angles and using the same language, within a constant exchange of ideas and texts comprehensible to all, in a period when educated Europe shared the same cultural patterns and language.
Chapter 10. Czech lands
Authors: Doležalová Lucie
Published: June 2024

The study presents a brief overview of Latin literature in the Czech lands from its beginnings at the end of the tenth century until ca. 1526. Special attention is paid to its blossoming during the reign of Charles IV (1346–1378), as well as to the European anomaly – the Hussite movement – during the fifteenth century.
Chapter 14. Baltic countries
Authors: Bugiani Piero
Published: June 2024

Latin literature from the Baltic countries is inextricably tied up with the German crusaders and the religious orders that accompanied them. Their interests are reflected in their writings, which are predominantly either historical and ethnographic or devotional. The chronicles and histories often display the biases and agendas of their authors, serving as ammunition in a rivalry between the various crusading orders and the newly established episcopates, all vying for authority.
Chapter 15. Africa (fifth-sixth century)
Authors: Bisanti Armando
Published: June 2024

After a brief introduction on the developments of Latin literature in Roman Africa and the problem of Africitas, this chapter traces a synthetic picture of Latin literature in Africa under the Vandalic domination (fifth-sixth century), in its relations with political and cultural history. The progress of Latin literature in Africa under the Vandals is examined with particular attention to auctores and their works. Among the most significant writers are Dracontius, Fulgentius, Corippus and the poets of the Antologia Latina (especially Luxorius).
Chapter 21. A “postcolonial” approach to medieval Latin literature?
Authors: Stella Francesco
Published: June 2024

The chapter proposes an unconventional approach to the interpretation of medieval and post-medieval Latin textuality as post-colonial literature, in the sense of “expressed in a cultural system that in the post-Roman age is inevitably different from the writer’s native one and in a language other than the mother tongue”. This approach allows a new understanding of medieval Latin literature and early modernity as a secondary system of cultural production and of language as a communication code that can be analyzed with the linguistic tools of SLA.
Chapter 27. Liturgy, drama, preaching, and narration
Authors: Boynton Susan
Published: June 2024

Medieval Latin liturgy, drama, and preaching are living, oral arts of performance as well as texts. They all constitute forms of storytelling and draw on narrative texts. In different yet related ways, liturgy, drama, and preaching are all exegetical in nature and share aspects of Biblical commentary. The written record offers insight into the performance of liturgy, drama, and preaching, which took on their full meaning in the moment of celebration and utterance.
Chapter 34. The conquest of literacy
Authors: Verbaal Wim
Published: June 2024

This contribution attempts to problematize the concept of vernacularization during the Western Middle Ages. Taking modern research on endangered languages as its point of departure, it distinguishes between two periods of vernacularisation, the earlier one determined by the desire to standardize vernacular writing (literization), the other one by a factor of literarization, i.e., creating a literary language and field. In both periods, Latin as the hegemonic language constitutes the catalyst for these processes as they develop within the vernacular field.