Search Results (113)

High-strength steel has high strength and low thermal conductivity, and its thin-walled parts are very susceptible to residual stress and deformation caused by cutting heat during the drilling process, which affects the machining accuracy and quality. High-strength steel thin-walled components are widely used in aerospace and other high-end sectors; however, systematic investigations into their temperature fields during drilling remain scarce, particularly regarding the evolution characteristics of the temperature field in thin-wall drilling and the quantitative relationship between drilling parameters and these temperature variations. This paper takes the thin-walled parts of AF1410 high-strength steel as the research object, designs a special fixture, and applies infrared thermography to measure the bottom surface temperature in the thin-walled drilling process in real time; this is carried out in order to study the characteristics of the temperature field during the thin-walled drilling process of high-strength steel, as well as the influence of the drilling dosage on the temperature field of the bottom surface. The experimental findings are as follows: in the process of thin-wall drilling of high-strength steel, the temperature field of the bottom surface of the workpiece shows an obvious temperature gradient distribution; before the formation of the drill cap, the highest temperature of the bottom surface of the workpiece is distributed in the central circular area corresponding to the extrusion of the transverse edge during the drilling process, and the highest temperature of the bottom surface can be approximated as the temperature of the extrusion friction zone between the top edge of the drill and the workpiece when the top edge of the drill bit drills to a position close to the bottom surface of the workpiece and increases with the increase in the drilling speed and the feed volume; during the process of drilling, the highest temperature of the bottom surface of the workpiece is approximated as the temperature of the top edge of the drill bit and the workpiece. The maximum temperature of the bottom surface of the workpiece in the drilling process increases nearly linearly with the drilling of the drill, and the slope of the maximum temperature increases nearly linearly with the increase in the drilling speed and feed, in which the influence of the feed on the slope of the maximum temperature increases is larger than that of the drilling speed. Full article

Driven by carbon neutrality and peak carbon policies, hydrogen energy, due to its zero-emission and renewable properties, is increasingly being used in hydrogen fuel cell vehicles (H-FCVs). However, the high cost and limited durability of H-FCVs hinder large-scale deployment. Hydrogen internal combustion engine hybrid electric vehicles (H-HEVs) are emerging as a viable alternative. Research on the techno-economics of H-HEVs remains limited, particularly in systematic comparisons with H-FCVs. This paper provides a comprehensive comparison of H-FCVs and H-HEVs in terms of total cost of ownership (TCO) and hydrogen consumption while proposing a multi-objective powertrain parameter optimization model. First, a quantitative model evaluates TCO from vehicle purchase to disposal. Second, a global dynamic programming method optimizes hydrogen consumption by incorporating cumulative energy costs into the TCO model. Finally, a genetic algorithm co-optimizes key design parameters to minimize TCO. Results show that with a battery capacity of 20.5 Ah and an H-FC peak power of 55 kW, H-FCV can achieve optimal fuel economy and hydrogen consumption. However, even with advanced technology, their TCO remains higher than that of H-HEVs. H-FCVs can only become cost-competitive if the unit power price of the fuel cell system is less than 4.6 times that of the hydrogen engine system, assuming negligible fuel cell degradation. In the short term, H-HEVs should be prioritized. Their adoption can also support the long-term development of H-FCVs through a complementary relationship. Full article

Rapidly expanding power demand in economically developing regions significantly amplifies the operational risks associated with the delayed commissioning of planned substations. This study proposes a data–physics fusion framework integrating analytic hierarchy process-based quantitative assessment with multi-voltage level grid evolution simulation. First, a novel set of evaluation indicators for assessing planned substation criticality, with weights determined through the analytic hierarchy process (AHP), was established, enabling rapid assessment of delay impacts on investments and identification of crucial substations. This approach addresses the fundamental limitation of traditional planning methodologies, which inadequately quantify the compound effects of substation commissioning delays on multi-voltage grid evolution and associated investment inefficiencies. Subsequently, a multi-voltage level grid evolution model was developed, which quantitatively measures the cascading effects of substation commissioning delays on both low-voltage grid development and multi-level grid construction investments. Case study validation demonstrated a strong linear correlation between the proposed substation importance scores and the incremental construction costs induced by delays. The simulation-driven impact assessment model exhibits superior accuracy in evaluating commissioning delay consequences on multi-voltage grid construction compared to conventional approaches. This research provides power grid planners with a robust decision support framework for optimizing substation construction scheduling and minimizing delay-related cost escalations in complex grid development scenarios. Full article

Background/Objectives: Microneedles represent an innovative transdermal drug delivery approach, especially for protein antigens. This study aimed to develop a dual-functional, dissolvable microneedle system loaded with β-glucan and fucoidan in a hyaluronic acid matrix to achieve transdermal immunomodulation and reactive oxygen species (ROS) regulation, exploring its potential in inflammatory disease management and antigen delivery. Methods: The microneedles were fabricated using a two-step casting method. Their morphology, mechanical strength, and dissolution kinetics were characterized. In vitro experiments evaluated the ROS-modulating effects on human dermal fibroblasts, while in vivo studies on C57 mice investigated immune activation and lymph node accumulation of ovalbumin antigen. Results: The microneedles exhibited a mechanical strength exceeding 7.45 N/needle and dissolved within 50 s. β-glucan transiently reduced ROS levels at 6 h followed by a rebound, whereas fucoidan sustained ROS suppression after 12 h. In mice, β-glucan-loaded microneedles triggered local immune activation, and fucoidan-incorporated microneedles enhanced ovalbumin accumulation in lymph nodes by 2.1-fold compared to controls. Conclusions: Integrating β-glucan’s immunostimulatory and fucoidan’s ROS-scavenging/lymphatic-targeting properties within a single microneedle platform offers a promising multifunctional strategy for treating inflammatory diseases and delivering protein antigens. Full article

The pigmentation and coloration of P. vannamei are primarily determined by the type and concentration of dietary carotenoids, with carotenoid-rich macroalgae serving as effective dietary supplements to enhance pigment accumulation and improve commercial quality. Five experimental diets were formulated with 3% brown algae (Saccharina japonica, SJ group; Sargassum fusiforme, SF group), red algae (Neoporphyra haitanensis, NH group), or 0.1% purified carotenoids (zeaxanthin, ZT group; fucoxanthin, FX group). The results showed that both macroalgae and carotenoid supplementation significantly enhanced weight gain rate (WGR) and specific growth rate (SGR) compared to the control group, with the zeaxanthin and fucoxanthin groups exhibiting the greatest improvements (1.6-fold and 1.3-fold, respectively). The N. haitanensis-supplemented diet, which had the highest carotenoid content, resulted in the most pronounced carotenoid accumulation (2.58-fold increase). Carotenoids were mainly deposited in the exoskeleton, followed by the hepatopancreas, with minimal accumulation in muscle tissue. α-Carotene and β-carotene contributed most to exoskeleton deposition, while lutein and zeaxanthin had weaker effects, and fucoxanthin showed no significant influence. Tissue-specific distribution patterns were observed: α-carotene and β-carotene were localized in the exoskeleton; fucoxanthin and zeaxanthin were found only in the exoskeleton and hepatopancreas, and astaxanthin was present in all three tissues. Furthermore, astaxanthin diesters (C20:5 and C22:6) were primarily detected in the exoskeleton and hepatopancreas, while monoesters (C16:0 and C18:0) were specific to muscle. These findings suggest that targeted supplementation of algal-derived carotenoids can enhance both growth and pigmentation in P. vannamei, providing a theoretical basis for the development of functional feeds to improve shrimp commercial quality. Full article

This paper presents an ultrasonic driving and detection system based on a CMUT array using MEMS technology. Among them, the core component CMUT array is composed of 8 × 8 CMUT array elements, and each CMUT array element contains 6 × 6 CMUT units. The collapse voltage of a single CMUT unit obtained through finite element analysis is 95.91 V, and the resonant frequency is 3.16 MHz. The driving section achieves 64-channel synchronous driving, with key parameters including an adjustable excitation signal frequency ranging from 10 kHz to 5.71 MHz, a delay precision of up to 1 ns, and an excitation duration of eight pulse cycles. For the echo reception, a two-stage amplification circuit for high-frequency weak echoes with 32 channels was designed, achieving a gain of 113.72 dB and −3 dB bandwidth of 3.89 MHz. Simultaneously, a 32-channel analog-to-digital conversion based on a self-calibration algorithm was implemented, with a sampling rate of 50 Mbps and a data width of 10 bits. Finally, the experimental results confirm the successful implementation of the driving system’s designed functions, yielding a center frequency of 1.4995 MHz and a relative bandwidth of 127.9%@−6 dB for the CMUT operating in silicone oil. This paper successfully conducted the transmit–receive integrated experiment of the CMUT and applied Butterworth filtering to the echo data, resulting in high-quality ultrasonic echo signals that validate the applicability of the designed CMUT-based system for ultrasonic imaging. Full article

Ganoderma capense, a member of the Ganoderma genus within the Polyporaceae family, has long been recognized for its high nutritional value and extensive use in traditional medicine. Its primary distribution is in China and South Africa, with the type locality being South Africa. This species is rich in a diverse array of bioactive compounds, including various polysaccharides, glycopeptide macromolecules, and various small-molecule compounds, such as sesquiterpenes, triterpenes, steroids, and alkaloids. Research indicates that these chemical constituents exhibit numerous pharmacological properties, including antioxidant, anti-inflammatory, and anti-tumor activities, as well as inhibition of acetylcholinesterase, reduction in blood lipids, and promotion of neural synapse growth. Apart from its use in traditional Chinese medicine, the components of G. capense are utilized globally for the treatment of a wide range of diseases, including Alzheimer’s disease, febrile convulsions, HIV, and diabetes. This underscores the extensive medical applications of G. capense, emphasizing its significance in contemporary and traditional healthcare. This review summarizes the latest research findings on the bioactive compounds and pharmacological effects of G. capense, compiled from databases such as PubMed, Web of Science, and Elsevier. This study aimed at providing researchers in this field with in-depth scientific insights and guidance, promoting further application and development in the pharmaceutical and food industries, and serving as a reference for subsequent exploration of active substances and the development of new disease treatments. Full article

The long-term coexistence of sea cucumber-associated microorganisms with their host enables them to jointly withstand the unique marine ecological environment, and possess great potential for producing various natural products. However, under conventional laboratory conditions, most biosynthetic gene clusters (BGCs) in these microorganisms remain silent, necessitating the establishment of effective activation strategies for exploring bioactive secondary metabolites (SMs). Histone acetylation status regulates chromatin structure and plays a crucial role in cellular physiology and fungal secondary metabolism. Penicillium sclerotiorum SD-36 was isolated from sea cucumbers in our previous study. Genome sequencing results indicate that this strain harbors as many as 52 BGCs, suggesting it holds a wealth of genetic resources essential for synthesizing diverse SMs. Here, we describe the impact of a class 1 histone deacetylase (HDAC), PsHos2, on secondary metabolism of sea cucumber-associated Penicillium sclerotiorum SD-36. The colony morphology and SM profile of ΔPsHos2 exhibited significant changes, with the emergence of multiple new compound peaks. Six compounds, including five azaphilones, which are characterized by a pyranoquinone core structure, were isolated from ΔPsHos2, and seventeen unreported potential azaphilone-related nodes were obtained using molecular networking based on LC-MS/MS. Transcriptome analysis revealed that PsHos2 influenced the expression of 44 BGC core genes. Specifically, seven genes within cluster 86.1, the putative BGC for azaphilones, were upregulated, including two polyketide synthase (PKS) genes. The results indicate that regulation based on class 1 HDACs is an important strategy for enhancing SM synthesis in sea cucumber-associated fungi and expanding the resources of marine natural products. Full article

Impulse ultrawideband (UWB) synthetic aperture radar (SAR) combines high-azimuth-range resolution with robust penetration capabilities, making it ideal for applications such as through-wall detection and subsurface imaging. In such systems, the performance of UWB antennas is critical for transmitting high-power, large-bandwidth impulse signals. However, two primary factors degrade radar imaging quality: (1) inherent limitations in antenna radiation efficiency, which lead to low-frequency signal loss and subsequent time-domain ringing artifacts; (2) impedance mismatch at the antenna terminals, causing standing wave reflections that exacerbate the ringing phenomenon. This study systematically analyzes the mechanisms of ringing generation, including its physical origins and mathematical modeling in SAR systems. Building on this analysis, we propose a Bayesian ringing suppression algorithm based on sparse optimization. The method effectively enhances imaging quality while balancing the trade-off between ringing suppression and image fidelity. Validation through numerical simulations and experimental measurements demonstrates significant suppression of time-domain ringing and improved target clarity. The proposed approach holds critical importance for advancing impulse UWB SAR systems, particularly in scenarios requiring high-resolution imaging. Full article

Medium- to long-term wind power output scenarios are crucial for power system planning and operational simulations. This paper proposes a two-stage hidden Markov model-based approach for modeling the time series output of multiple wind farms. First, based on the key features of the wind power output sequence, the daily typical patterns of wind power output are extracted. Then, the process of simulating the wind power output time-series is modeled as a two-layer temporal model. The upper layer uses a discrete hidden Markov model to describe the day-to-day transition process of wind power output patterns and the lower layer uses a Gaussian mixture hidden Markov model to describe the fluctuation process of wind power output values within each output pattern. Finally, the upper models corresponding to each quarter and the lower models corresponding to each pattern are trained respectively and the time-series scenarios of wind power output for multiple wind farms are generated quarter-by-quarter and day-by-day through Monte Carlo sampling. Validation using real-world wind power data demonstrates that the proposed method can effectively generate medium- to long-term output scenarios for multiple wind farms. Compared to traditional methods, the proposed method shows improvements in terms of accuracy, statistical characteristics, temporal correlation, and mutual correlation. Full article

Drought stress, being a crucial abiotic stress factor, and its recovery mechanism after rehydration are important in regulating crop production. This meta-analysis investigates the effects of drought stress followed by rewatering (DSRW) on crop productivity and water use efficiency (WUE) in Chinese cropping systems, synthesizing data from 90 studies (1997–2023) encompassing 2606 experimental observations. Results indicate that DSRW significantly reduced crop yield (CY) across plant types, with monocots (20.31% decline) outperforming dicots (23.64%) and woody plants (19.98% decline) showing greater resilience than herbaceous species (21.52%). WUE improved in woody plants (+7.81%) but declined in herbaceous crops (−9.44%), with notable increases in Chenopodiaceae (+59.39%) and Malvaceae (+11.35%). Mild drought stress (>65% field capacity) followed by short-term rewatering during early growth stages minimized CY losses (−19.60%) and WUE reduction (−6.89%), outperforming moderate or severe stress. Physiological analyses revealed DSRW-induced declines in photosynthetic parameters (e.g., net photosynthetic rate: −11.54%) but enhanced antioxidant enzyme activities (CAT: +18.21%, SOD: +10.23%) and osmoregulatory substance accumulation (proline: +16.22%). The study highlights the compensatory potential of strategic rewatering timing and intensity, advocating for early-stage, mild drought interventions to mitigate yield losses, which provide a practical value for promoting the sustainable development of water-saving agriculture. Future research should address regional climatic variability and crop quality responses to DSRW, advancing climate-resilient agricultural practices. Full article

The spraying time of nitrogen fertilizer is a key factor to consider when fertilizing with an intelligent micro-sprinkler irrigation system. This study aims to investigate the impact of nitrogen fertilizer spraying time on the seed oil quality of tree peony, with the expectation of providing theoretical support for the application of intelligent micro-sprinkler irrigation systems in the production of tree peony. In 2022 and 2023, foliar nitrogen application was conducted on Paeonia ostii ‘Fengdan’ utilizing an intelligent micro-spray irrigation system, with four distinct nitrogen fertilizer spraying times (3:00–4:00, 7:00–8:00, 14:00–15:00, and 19:00–20:00). Based on this, the study assessed nitrogen metabolism indicators in leaves and seeds at various growth stages and the fatty acid composition of seed oil in Paeonia ostii ‘Fengdan’. The results revealed that foliar nitrogen application between 14:00 and 15:00 significantly enhanced the levels of free amino acids (FAA), nitrate reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT) activity in both leaves and seeds. Furthermore, the ratio of α-linolenic acid in the seed oil was significantly increased. Correlation analysis demonstrated a positive or highly significant positive correlation between the levels of nitrogen metabolism indicators and the ratio of unsaturated fatty acids. In conclusion, foliar nitrogen application between 14:00 and 15:00 significantly enhances the FAA content and the activity of nitrogen metabolism enzymes within the leaves and seeds and promotes the synthesis of unsaturated fatty acids in seed oil. This study contributes to the efficient and high-quality cultivation of tree peony. Full article

Bone tissue is intrinsically electroactive, and electrical signaling is one of its key regulatory mechanisms. The electroactive poly (vinylidene fluoride trifluoroethylene) (PVTF), due to its piezoelectricity, can provide electrical stimulation to cells, regulating their proliferation and osteogenic differentiation. Collagen I (COL) is the main organic component of bone and is involved in various physiological processes of bone. A crucial question that remains to be explored is whether electroactive materials can meet the requirements for GBR membranes and what synergistic effects electrical signals and collagen’s biochemical signals might have on cellular behavior. In this study, PVTF/COL composite films were prepared using polydopamine (PDA). It was found that collagen modification could increase the surface Kelvin potential of PVTF from −5.07 V to 2.22 V, reduce the WCA from 98.9° to 33.2°, and maintain the tensile strength of PVTF at 24.94 MPa. Additionally, the composite film significantly promoted the adhesion and proliferation of bone marrow stem cells (BMSCs), and the ALP activity on PPC3 films after 7 days was 5.6 times higher than that on P films. This study presents a novel and effective approach for surface modification of PVTF and explores its potential applications in GBR. Full article

Axial force and deformation during drilling significantly impact the hole quality of thin-walled high-strength steel components. This study analyzed the drilling process of thin-walled AF1410 steel, focusing on axial force, deformation, drill cap formation, and hole exit edge characteristics. The effects of cutting speed (12.6–37.7 m/min) and feed rate (0.01–0.1 mm/r) were also examined. Initially, the steel plate undergoes elastic, outward bulging deformation. Axial force, driven by elastic resistance, rises from 114.9 N to 322.1 N as feed rate increases from 0.025 mm/r to 0.1 mm/r, with minimal influence from cutting speed. As drilling progresses, axial force increases slowly. Near the hole exit, plastic deformation occurs beneath the drill bit, causing material to yield and form a drill cap. This results in a sharp rise in axial force, with maximum values increasing from 314.2 N to 525.3 N at higher cutting speeds and from 314.2 N to 840.1 N at higher feed rates. The formation characteristics of the drill cap directly affect hole edge defects, with larger thickness and width leading to more pronounced burrs. Full article

This study investigated the effects of dietary iron supplementation on water quality, plant growth, and fish health in an aquaponic system over 90 days. Iron supplementation significantly improved plant growth, with increased plant height, stem diameter, leaf count, and fruit yield in tomatoes (Solanum lycopersicum) and pak choi (Brassica rapa subsp. Chinensis) (p < 0.05). The water pH fluctuated with varying iron content, and higher iron levels promoted better plant growth by improving iron availability (p < 0.05). During the first 60 days, all red blood cell counts and hemoglobin levels increased, but the growth and nutritional composition of mirror carp (Cyprinus carpio var. specularis) showed no significant differences. By day 90, fish in the T3 group (800 mg/kg iron) exhibited significantly reduced growth and feed conversion rates (p < 0.05). Histological analysis of liver tissue indicated iron-induced liver damage; additionally, excessive iron intake suppressed erythropoiesis, leading to lower red blood cell counts and hemoglobin levels (p < 0.05). The results indicate that moderate iron supplementation improves plant growth, but excessive iron can negatively impact fish health, particularly liver function and blood formation. These findings provide valuable insights for optimizing iron levels in aquaponic systems. Full article