Search Results (184)

The present study was carried out using a cold-drawn wire of Ni_50.8Ti at.% subjected to post-deformation solution treatment at 700 °C for 1 h to obtain a fine-grained recrystallized structure. Subsequent aging was carried out at a temperature range of 300, 430, and 500 °C for 1, 10, and 20 h. The time–temperature aging mode strongly affects the aging-induced microstructure. Variation of the aging-induced microstructure (using various aging modes) permits precise tuning of the characteristic temperature of the martensitic transformations and their specific temperature ranges upon cooling and heating. The latent heat and hysteresis exhibit different evolution vs. aging durations; this finding remains fair when using different aging temperatures. The aging mode strongly affects the stress–temperature behavior: (i) a dramatical expansion of the temperature range of realization of the transformation yield stress (σ_tr); and (ii) the magnitude of σ_tr at a chosen test temperature is generally determined by the position of the M_s temperature. An additional contribution of competing factors is discussed. The efficiency of the aging temperature under isochronous aging is significantly higher than the efficiency of the aging time under isothermal aging. Aging at 430 °C for 10–20 h provides the highest resource for the recovery strain. The strain–temperature behavior strongly depends on the relative position of the R_s and M_s temperatures (onset of B2→R and R→B19′ transformations, respectively). The regularities obtained can be used to predict the set of functional and mechanical properties of titanium nickelide. Full article

This study aimed to examine whether different rhythm idioms significantly affect the reproduction accuracy of older adults and whether the participants’ age and personal current engagement in music affect their ability to reproduce rhythm. A total of 79 older adults participated in the study. Participants were required to reproduce six different rhythm idioms, and their accuracy in rhythm reproduction was measured using the R index. The data were analyzed considering the participants’ age sub-group and current engagement in music. The findings showed differences in reproduction accuracy across various rhythm idioms, particularly in relation to steady recurring notes and dotted notes with different intervals. The highest reproduction accuracy was found for the isochronous beat pattern, while the rhythm idiom starting with longer intervals yielded the lowest accuracy. Age and current personal engagement in music did not significantly affect rhythm performance. However, the study identified a significant correlation between decreased accuracy in reproducing a steady rhythm and diminished general cognitive ability. This study indicates that rhythm performance can be indicative of cognitive abilities related to temporal information processing. The findings support the potential use of rhythm tasks to evaluate cognitive performance in older adults with varying cognitive levels. Full article

Air pollution, particularly fine particulate matter (PM), poses significant health risks to vulnerable populations such as children, older adults, and individuals with chronic illnesses. Understanding the spatial distribution of these populations and their access to air quality information is crucial for effective interventions. In urban areas like Gangseo District, the distribution of essential facilities and accessibility varies greatly. While studies have highlighted the health impacts of PM, research on optimizing air quality monitoring for at-risk groups remains limited. This study aims to identify optimal locations for air quality monitoring by analyzing the spatial distribution of vulnerable populations and facility accessibility. Using Geographic Information Systems (GIS) and isochrone maps, we identified areas with high concentrations of vulnerable groups and poor access to healthcare facilities. Our findings revealed significant disparities in access to air quality information, with some high-risk areas underserved by current monitoring systems. This study integrated demographic data and spatial analysis to propose strategic monitoring placements. The methodology can be applied to other urban settings and offers a framework for improving air quality management. This study underscores the importance of targeted air quality monitoring to protect vulnerable populations and suggests practical steps for policymakers to enhance public health. Full article

Timing and/or position-sensitive MCP detectors, which detect secondary electrons (SEs) emitted from a conversion foil during ion passage, are widely utilized in nuclear physics and nuclear astrophysics experiments. This review covers high-performance timing and/or position-sensitive MCP detectors that use SE emission for mass measurements of exotic nuclei at nuclear physics facilities, along with their applications in new measurement schemes. The design, principles, performance, and applications of these detectors with different arrangements of electromagnetic fields are summarized. To achieve high precision and accuracy in mass measurements of exotic nuclei using time-of-flight (TOF) and/or position (imaging) measurement methods, such as high-resolution beam-line magnetic-rigidity time-of-flight (Bρ-TOF) and in-ring isochronous mass spectrometry (IMS), foil-MCP detectors with high position and timing resolution have been introduced and simulated. Beyond TOF mass measurements, these new detector systems are also described for use in heavy ion beam trajectory monitoring and momentum measurements for both beam-line and in-ring applications. Additionally, the use of position-sensitive timing foil-MCP detectors for Penning trap mass spectrometers and multi-reflection time-of-flight (MR-TOF) mass spectrometers is proposed and discussed to improve efficiency and enhance precision. Full article

Catheter ablation for ventricular tachycardia (VT) in patients with systolic heart failure remains a critical yet challenging area of non-pharmacological therapy. Despite positive outcomes in atrial fibrillation, evidence for the efficacy of VT ablation in reducing cardiac mortality is inconclusive due to the absence of standardized ablation strategies. The primary challenges include difficulties in identifying suitable ablation targets and their deep locations within myocardial tissue. Current techniques, such as voltage mapping, provide valuable insights; however, they are limited by the presence of numerous bystander areas and the occurrence of incomplete transmural scarring. Recent advancements in functional substrate mapping have focused on identifying critical isthmuses without requiring hemodynamic stabilization during VT, thereby shifting the emphasis to the analysis of potentials during baseline rhythm. While methods like isochronal late activation mapping have improved target identification, they primarily address conduction abnormalities without adequately considering repolarization heterogeneity. This review highlights emerging technologies that utilize unipolar potentials to assess repolarization heterogeneities and identify VT isthmuses. Furthermore, novel ablation sources such as pulsed-field ablation, bipolar ablation, and ultra-low temperature cryoablation are being explored to create deeper and more durable lesions, addressing the limitations of traditional radiofrequency ablation. These advancements aim to reduce VT recurrence and improve overall treatment efficacy. Ultimately, understanding these innovative strategies is expected to optimize procedural outcomes and significantly enhance the management of patients with scar-related VT. Full article

Despite the great success in the global exploration and development of reef reservoirs, research on bioclastic shoals under reefs is still in its infancy. Bioclastic shoal reservoirs are very thin, with multiple vertical levels and fast lateral changes, which makes accurate prediction of the reservoir’s location much tougher. To further implement the reservoir distribution, under the guidance of sequence stratigraphy, the prediction of thin shoals under the control of an isochronous stratigraphic framework was established. Using the combination of spectrum shaping and F-X domain noise suppression techniques and utilizing the signal-to-noise ratio spectrum set as the reference, logging curve as supervision, and well seismic calibration and isochronal amplitude slicing as quality control, the seismic frequency band was extended, and the seismic data resolution and signal-to-noise ratio were improved. After frequency extension, the global optimal seismic automatic interpretation technique was used to construct an isochronal stratigraphic framework model. Through waveform facies-controlled inversion and waveform facies-controlled simulation techniques, the elastic properties of the shoal reservoir were obtained, from which the planar distribution of the reservoir was accurately predicted. The above methods were applied to the prediction of the bioclastic shoal reservoir in the lower submember of the Changxing formation in the Yuanba gas field (China). The plane distribution of bioclastic shoal in the first and second levels was identified, which provides a guideline for the prediction of thin shoal reservoirs. Full article

The Waxing Mo polymetallic deposit is located in the central part of the Lesser Xing’an–Zhangguangcai Range (LXZR), NE China. The Mo (Cu) mineralization in the deposit is dominantly hosted by quartz veinlets and stockworks and is closely related to silicification and potassic alteration, while the W mineralization is most closely related to greisenization. Zircon samples from granodiorite, biotite monzogranite, granodiorite porphyry, and syenogranite in the Waxing deposit yielded U-Pb ages of 172.3 Ma, 172.8 Ma, 173.0 Ma, and 171.4 Ma, respectively. Six molybdenite samples from porphyry Mo ores yielded a Re-Os isochron age of 172.0 ± 1.1 Ma. The granitoids in the ore district are relatively high in total alkali (Na₂O + K₂O), are metaluminous to weakly peraluminous, and are classified as I-type granitoids. The zircon samples from all granitoids showed a relatively consistent Hf isotopic composition, as shown by positive ε_Hf(t) values (3.1–8.3) and young T_DM2 ages (0.69–1.25 Ga). These results, combined with the whole-rock geochemistry, suggest that the magma source of these rocks most likely derived from partial melting of a juvenile middle-lower continental crust, with a minor contribution from the mantle. These granitoids have compositional characteristics of adakites such as relatively high Sr contents (e.g., >400 ppm) and Sr/Y ratios (e.g., >33), as well as weak Eu anomalies (e.g., Eu/Eu* = 0.8–1.1), indicating extensive fractionation crystallization of a hydrous magma. The apatite geochemistry indicates that the ore-related magma in Waxing is F-rich and has a relatively low content of sulfur. The zircon geochemistry reveals that the granodiorite, biotite monzogranite, and granodiorite porphyry have relatively high oxygen fugacity (i.e., ΔFMQ = +1.1~1.3), whereas the fO₂ values of the granite porphyry and syenogranite are relatively low (i.e., ΔFMQ = +0.1~0.5). The whole-rock and mineral geochemistry suggest that the Mo mineralization in Waxing is probably genetically related to granitoids (i.e., granodiorite, biotite monzogranite, and granodiorite porphyry), with higher oxygen fugacity and a high water content, whereas the magmatic S concentration is not the key factor controlling the mineralization. A comparison of the geochemical compositions of ore-forming and barren stocks for porphyry Mo deposits in the LXZR showed that geochemical ratios, including Eu/Eu* (>0.8), 10,000*(Eu/Eu*)/Y (>600), Sr/Y (>33), and V/Sc (>8), could be effective indicators in discriminating fertile granitoids for porphyry Mo deposits from barren ones in the region. Full article

The Zhueryu Au deposit is one of the important quartz-vein type Au deposits. It is located at the western margin of the Jidong gold belt in China and characterized by ore bodies hosted in structural fractures within the Zhueryu syenite. The H, O, and S isotopes as well as the Rb–Sr isotope age of fluid inclusions from the quartz-polymetallic sulfide ore bodies (main stage) and the zircon U–Pb isotope age from the syenite were analyzed so as to discuss the source of ore-forming fluids and constrain the Au’s mineralization age. The textural characteristics of the fluid inclusions indicate that the fluid inclusions in the quartz (QzII) are from the same stage, with no evidence of secondary fluid inclusions from the later stage. Fluid inclusion microthermometry performed on the quartz (QzII) reveals a predominance of vapor–liquid two-phase inclusions, with homogenization temperatures ranging from 177 °C to 337 °C (average: 260 °C), characteristic of a medium-low temperature hydrothermal system. Furthermore, H, O, and S isotope analyses of the ore-forming fluids yielded δD, δ¹⁸O, and δ³⁴S values ranging from +12.8‰ to +14.8‰, +9.15‰ to +9.51‰, and −8.395‰ to -1.918‰ (average: −5.826‰), respectively. These isotopic signatures, particularly the distinctly positive δD values, strongly suggest that the Zhueryu ore-forming fluids were primarily derived from metamorphic sources, contrasting with the magmatic-hydrothermal fluids implicated in the formation of many other Au deposits within the Jidong belt. The LA–ICP–MS zircon U–Pb dating yielded a concordia age of 242 ± 2 Ma (MSWD = 0.17), indicating a Middle Triassic crystallization age for the Zhueryu syenite. In contrast, the Rb–Sr dating of primary fluid inclusions hosted within quartz (QzII) yielded an isochron age of 181 ± 12 Ma (MSWD = 2.5), placing the Au mineralization event firmly within the Early Jurassic. This demonstrates that the Au mineralization is significantly younger than the host syenite, representing a distinct mineralization event. These results might have certain significance for studying the dynamics of Au mineralization in the Jidong gold belt. Full article

Traditional seismic wave-based tunnel advanced geological forecasting techniques are primarily designed for drill and blast method construction tunnels. However, given the fast excavation speed and limited prediction space in tunnel boring machine (TBM) construction tunnels, traditional methods have significant technical limitations. This study analyzes the characteristics of different types of TBM construction tunnels and, considering the practical construction conditions, identifies an effective observation system and data acquisition method. To address the challenges in advanced forecasting for TBM construction tunnels, a method of ellipsoid positioning velocity analysis, which takes into account the constraints of three-component data directions, is proposed. Based on the characteristics of the advanced forecasting observation system, this method compares the maximum values on the spatial isochronous ellipsoidal surface to determine the average velocity of the geological layer rays, thereby enabling accurate inversion of the spatial distribution ahead. Utilizing numerical simulation, a model for the advanced detection of typical unfavorable geological formations is established by obtaining the wave field response characteristics of seismic waves in three-dimensional space, and the velocity structure of the model is retrieved through this velocity analysis method. In the engineering example, the fracture property, water content, and weathering degree of the surrounding rock are predicted accurately. Full article

Over the last several decades, cities have seen concentrated development and population increase. It is a global process, still unfinished, that has simultaneously generated strong territorial imbalances because of socioeconomic backwardness and depopulation of rural areas. The alternative proposed by all institutions is a polycentric urban system, so that cities contribute to decentralizing this development towards their respective areas of influence, thus stabilizing the populations in them. Extremadura is a paradigmatic example, since it has a polycentric system of small cities that have been able to retain half of the population in rural areas. The objective of this article, first, is to define the urban structure and, based on this, typify the range, the hierarchy of the system and its territorial distribution, for which a multivariate analysis is applied. Secondly, a series of isochrones and displacement ranges are defined to analyze urban accessibility, which is key to determining the degree of decentralization of development and population stability. However, a wide peripheral and remote strip remains in the region, for which a concrete proposal is finally made for discussion. Full article

Objective: There is a demand to make hospital management information beyond basic key performance indicators (KPIs) accessible for clinicians. Methods: We developed an interactive application (IAPP) in R Shiny to visualize such information. We provided the IAPP source code online. As a use case, we recorded basic KPIs (numbers of patients (NPs), reimbursed valuation ratios (RVRs), mean length of stay (LOS)), main diagnoses (MDGNs), main procedures (MPRCs), and catchment area (CA) by district from April 2022 to March 2024 at the index department in central Germany, where a neurotrauma and spinal surgery service was resumed on 1 April 2022. Case mix indexes (CMIs) were calculated. We retrieved information about online-reported patient satisfaction (ORPS) from an online physician rating platform between January 2022 and March 2024. Information on longitudes and latitudes of the index department and neighbouring hospitals was collected. We calculated car travelling isochrones (CTIs) of the hospitals as a proxy variable for accessibility. Chi-square and Fisher’s exact served as statistical tests. Results: During the observation period, the monthly NPs increased from 26 to 43, the RVR showed a 3.96-fold increase, the CMI showed a 2.41-fold increase, and the LOS reached a steady state in the 2nd year after service resumption. CA (p = 0.03), MDGNs, and MPRCs diversified. ORPS trended towards better overall evaluation after service resumption (p = 0.09). CTI mapping identified a unique market position of the index department. Conclusions: The IAPP makes extended hospital management data accessible to clinicians, can inform other stakeholders in healthcare, and can be tailored to local conditions. Full article

Gas well production involves various stages, including stable, variable, and declining production. However, existing production-capacity equations typically apply only to the stable production stage, limiting their effectiveness in evaluating gas well productivity across all stages. To address this, the material balance equation and Darcy’s equation were employed to account for changes in average formation pressure due to pressure drop funnels. The concept of a pressure-conversion skin factor was introduced, and its approximation was developed, leading to the establishment and solution of a full-stage productivity equation. Numerical simulations were then conducted to verify the accuracy and applicability of this equation. The findings are as follows: ① The full-stage productivity equation remains effective even when production rates and pressure are not constant, with the only potential source of inaccuracy being the approximative solution for the pressure conversion-skin factor. ② Numerical simulations demonstrated that the approximate solution closely matched the numerical simulation results for average formation pressure across various production stages and fundamental parameters, showing a consistent trend and high precision. The approximate and independent approximation solutions for absolute open-flow capacity were nearly identical, indicating the full-stage productivity equation’s applicability throughout the production of gas wells. ③ Application results revealed that the full-stage productivity equation offers superior accuracy compared to the modified isochronous well test. ④ The approximate solution generally provides slightly higher accuracy, and the independent approximate solution effectively eliminates the influence of gas leakage radius. Therefore, the use of the approximate solution is recommended to calculate the average formation pressure and the independent approximate solution to calculate the absolute open-flow capacity. The full-stage productivity equation developed in this study is not constrained by the production system, making it suitable for productivity evaluation across all stages of gas well production. This has significant implications for the effective development of gas fields. Full article

Pre-hospital emergency medical service (PHEMS) is critical for the treatment outcomes of life-threatening injuries and time-sensitive illnesses. Response time, influenced by traffic conditions and the site planning of pre-hospital emergency medical facilities (PHEMFs), is the main indicator for evaluating PHEMS. In 2020, the Beijing government released the “Special Plan for Spatial Layout of Pre-hospital Emergency Medical Facilities in Beijing (2020–2022)”. This paper evaluates the functional efficiency and spatial equity of this plan within Beijing’s central six districts using isochrone measures to assess the accessibility of the planned PHEMFs. The isochrone coverages of the area and population were calculated, and the temporal-spatial characteristics of isochrones were concluded. The analysis revealed that while the current planning meets several objectives, challenges in service availability and equity persist. Although 10-min isochrone coverage was high, 8-min coverage was insufficient, particularly during peak hours. This highlights gaps in service accessibility that necessitate additional emergency stations in underserved areas. The current planning approach leads to significant overlap at administrative boundaries, causing service oversupply and increased costs, which calls for a city-wide planning perspective that breaks administrative boundaries to optimize resource allocation. Traffic conditions significantly impact service coverage, with congestion reducing coverage in central areas and better coverage near traffic hubs. Future planning should strategically place stations based on traffic patterns and population distribution to enhance emergency medical service accessibility and equity in urban areas. Full article

Recent developments in ultrashort and intense laser systems have enabled the generation of short and brilliant proton sources, which are valuable for studying plasmas under extreme conditions in high-energy-density physics. However, developing sensors for the energy selection, focusing, transport, and detection of these sources remains challenging. This work presents a novel and simple design for an isochronous magnetic selector capable of angular and energy selection of proton sources, significantly reducing temporal spread compared to the current state of the art. The isochronous selector separates the beam based on ion energy, making it a potential component in new energy spectrum sensors for ions. Analytical estimations and Monte Carlo simulations validate the proposed configuration. Due to its low temporal spread, this selector is also useful for studying extreme states of matter, such as proton stopping power in warm dense matter, where short plasma stagnation time (<100 ps) is a critical factor. The proposed selector can also be employed at higher proton energies, achieving final time spreads of a few picoseconds. This has important implications for sensing technologies in the study of coherent energy deposition in biology and medical physics. Full article

Analysing the spatial distribution patterns of the urban tourism and leisure industry is crucial for meeting the dual demands of residents and visitors for a better quality of life. Most existing studies on spatial distribution characteristics and the accessibility of leisure tourism have been carried out individually and lack the relationship between the tourism and leisure industry and accessibility. Based on Qingdao’s POI data, spatial visualisation methods and Geodetector are used to explore spatial distribution, accessibility, and influencing factors. (1) It is found that the overall and various types of the tourism and leisure industry in Qingdao exhibit clustered distribution, with an imbalance between coastal and inland areas. (2) There are notable spatial disparities in overall accessibility within Qingdao, with most regions falling within the 70-min isochrone. The spatial distribution of accessibility at the county level aligns with the overall accessibility patterns. (3) Various factors influence the spatial distribution of the tourism and leisure industry. Per capita disposable income is the primary factor affecting the spatial layout of Qingdao’s tourism and leisure industry. After interacting with other factors, GDP per capita and tourist trips become key influencing factors. These findings can promote the sustainable development of urban tourism in Qingdao and provide a valuable reference for other cities. Full article