High-voltage dry-type bushings, serving as the crucial junctions in DC power transmission, represent equipment with the highest failure rate on the DC primary side, underscoring the critical ...importance of monitoring their condition. Presently, numerical simulation methods are commonly employed to assess the internal state of bushings. However, due to limitations in the efficiency of multi-physics field computations, the guidance provided by numerical simulation results in the field of power equipment condition assessment is relatively weak. This paper focuses on solving the electrical-thermal coupling in high-voltage dry-type bushings. Addressing the most widely used tetrahedral mesh in numerical computations, we propose an efficient solution method based on the concept of "smooth domains." This method involves partitioning the volume centroids of the elements into multiple smooth domains within the computational domain. Electric and thermal conduction matrix calculations occur within these smooth domains, rather than within the grid or element interiors. This approach eliminates the need for traditional element mapping and complex volume integration. To demonstrate the effectiveness of this method, we use high-voltage dry-type bushings as a case study, comparing the performance of our approach with traditional finite element algorithms. We verify the algorithm's computational efficiency and apply it to the analysis of typical temperature anomalies in bushings, further illustrating its suitability for electrical equipment condition assessment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A fiber/Ag-Cu films surface plasmon resonance (SPR) refractive index (RI) sensor composed of multimode fiber-no-core-fiber-multimode fiber (MMF-NCF-MMF) structure is designed. The sensing region ...length and Cu film deposition time of sensor are gradually optimized by the control variable method, which finally achieves the improvement of sensor properties. We experimentally compared the sensing performance of the fiber/Ag film and fiber/Ag-Cu films sensor. Experimental results show that the fiber/Ag-Cu films sensor has good linearity (R-square = 0.993), and its sensitivity is as high as 3957 nm/RIU in the refractive index detection range of 1.3328–1.3853, which is 1109 nm/RIU higher than the sensitivity of a conventional fiber/Ag film sensor. The sensor presented in this paper adopts the structure with composite metal film, which outperforms the common single-layer metal film in chemical stability such as oxidation resistance and mechanical hardness. Meanwhile, the SPR sensor with MMF-NCF-MMF structure has the advantages of convenient manufacture and compact structure. In conclusion, it can bestow a unique advantage in the field of biological detection or chemical analysis.
The Late Triassic Tianqiaoling flora is well-known in China, and its discovery has changed our understanding of Chinese Late Triassic phytogeographical divisions. More broadly, this flora has great ...significance for the study of phytogeography in East Asia during this time. However, the previous dating of this flora was only evidenced by plant fossils and stratigraphic correlation, and the accurate dating has still not been achieved. In this study, rhyolite samples were collected from the bottom of the Tianqiaoling Formation, which is conformally contacted the Tianqiaoling flora-bearing beds. The results of new U-Pb dating gave ages for the rhyolites of 212.8±2.5 Ma, indicating the end of Malugou Formation and initial Tianqiaoling Formation in deposition occurred in the late Norian (~227–208.5 Ma), which is contemporaneous with the peak of the Tianqiaoling flora in development. Our radiometric dating results are basically consistent with paleobiological evidence. The new age provides a key anchor point for regional stratigraphic correlation of the Tianqiaoling flora with its related Late Triassic floras, and contribute to a better understanding of the geology and phytogeography in the East Asia, particularly in the “triangle region” covering the eastern Jilin (China), South Primorye (Russia) and Southwest Japan, during the Late Triassic.
Ferrite rolling is generally used to produce deep-drawn steel sheets, which can replace cold rolling to achieve short-flow production. Realizing low-cost production of deep-drawn steel. However, the ...deep-drawn performance of ferrite rolling products is not as good as the deep-drawn performance of cold rolled products. Of which dynamic recrystallization microstructure have a great effect on the deep-drawn performance. In the present study, ferrite steel was compressed at different deformation parameters (including deformation temperatures and strain rates) in a thermo-mechanical testing system to simulate the deformation behavior during the ferrite regions. The flow behavior of the ferrite steel was studied, and processing maps of the ferrite steel were plotted. The relationship between the Zener-Hollomon parameter and the dynamic recrystallization mechanisms of the ferrite steel was studied in this paper. The microstructure evolution in the steel was characterized by optical microstructure, electron backscatter diffraction, and transmission electron microscopy. The results show that both dynamic recovery and dynamic recrystallization happened during deformation process. The main softening mechanism was dynamic recovery. Discontinuous dynamic recrystallization, continuous dynamic recrystallization and geometric dynamic recrystallization were found in ferrite steel. Meanwhile, it was found that a corresponding relationship between dynamic recrystallization mechanisms and ln Zener-Hollomon values. At high ln Zener-Hollomon value, the dynamic recrystallization mechanism was discontinuous dynamic recrystallization. At middle ln Zener-Hollomon value, the dynamic recrystallization mechanism was continuous dynamic recrystallization. At low ln Zener-Hollomon value, the dynamic recrystallization mechanism in addition to continuous dynamic recrystallization and geometric dynamic recrystallization.
The Upper Cretaceous Yong'ancun Formation of the Jiayin area, outcropping along the Heilongjiang (Amur) River in China and yielding fossil plants and dinosaurs, has been considered Santonian in age ...mainly based on palynostratigraphic studies. Until now, there is no document on isotopic dating and guide fossils from this formation, limiting stratigraphic correlation with its equivalents from adjacent basins. This study reports a new age (84.64 ± 0.65 Ma, late Santonian) for the Yong'ancun Formation based on zircon LA-ICP-MS U–Pb dating for the first time from a rhyolitic tuff in the top of the unit. Ghoshispora, a fossil genus of megaspore of water fern is also reported for the first time, co-occurring with other valuable guide fossils such as G. zhaoi and G. triangulata. Based on the presence of Ghoshispora and plant megafossils, the flora of the Yong'ancun Formation is now interpreted to reflect a moist and warm climate, implying that the temperature dropped from high (mid-Cretaceous thermal maximum, KTM) to moderate warm and wetter conditions, at least in the Heilongjiang (Amur) inland region, close to the paleo-Pacific Ocean. The new discovery and dating evidence could provide valuable data for the correlation with the Yaojia Formation of the Songliao Basin, China.
•LA-ICP-MS U–Pb date (84.64 ± 0.65 Ma) from the rhyolitic tuff of the Yong'ancun Formation reported for the first time.•The newly found water fern megaspore Ghoshispora is a valuable stratigraphic and palaeoenvironmental fossil.•The Yong'ancun Formation is the equivalent to the Yaojia Formation of the Songliao Basin (middle to late Santonian).
The coal-bearing Jixi Basin of Heilongjiang is a unique Cretaceous basin in Northeast China, depositing non-marine alternated marine strata during transgressions in the Early Cretaceous. However, the ...ages of the Didao-, Chengzihe- and Muling formations and their relationships to transgressions and regressions have been under debate mainly due to a lack of radiometric constraints and comprehensive study of the fossils. The authors report results of new LA-ICP-MS zircon dating from the tuff of the Didao Formation in its type section (131.5 ± 1.4 Ma), which is the oldest isotopic dating data reported for the Early Cretaceous in eastern NE China. This dating result shows the earliest known volcanic activity happened in the Hauterivian stage, which implies the initial rifting of the Jixi Basin probably in the Hauterivian and caused the first sea staged regression eastward or northeastward in Jixi Basin during the Early Cretaceous. Additionally, a comprehensive study of the plant and dinoflagellate fossils, new dating, and the regional paleogeographic characteristics, indicates a Valanginian-Hauterivian age for the Didao Formation, improving the stratigraphic study of the Didao Formation in accuracy. Moreover, according to the dating in the eastern Northeast China, the four volcanic stages in this region during the Early Cretaceous can be recognized as follows (i) the Didao volcanic stage (ca. 130–132 Ma); (ii) Early Chengzihe-Boli volcanic stage (ca. 119–126 Ma); (iii) Late Chengzihe-Muling volcanic stage (ca. 110–117 Ma); (iv) the Dongshan volcanic stage (ca. 101–108 Ma).
The mode and mechanism of diabetic periodontitis-induced alveolar-osteocyte death are still unclear. This study aimed to investigate the occurrence of ferroptosis in alveolar osteocytes during ...diabetic periodontitis and the therapeutic potential of resveratrol to alleviate osteocyte ferroptosis. Diabetic periodontitis was induced in C57/BL6-male mice and treated with or without resveratrol. Periodontitis pathogenicity was analyzed by micro-CT and histology, and alveolar-osteocyte ferroptosis was analyzed by immunohistochemistry. MLOY4 osteocytes were treated with
-derived lipopolysaccharide (LPS)+advanced glycosylated end products (AGEs) mimicking diabetic periodontitis condition in vitro, with or without resveratrol or ferrostatin-1 (ferroptosis inhibitor). Osteocyte ferroptosis and expression of inflammatory mediators were analyzed. Diabetic periodontitis aggravated periodontitis pathogenicity and inhibited the expression of GPX4 and SLC7A11 in alveolar osteocytes and resveratrol alleviated these effects. LPS+AGEs triggered osteocyte ferroptosis in vitro as indicated by the downregulated GPX4 and SLC7A11, upregulated malondialdehyde, disrupted mitochondrial morphology, and overexpressed pro-inflammatory mediators IL-1β, TNF-α, SOST, RANKL, and IL-6, and ferrostatin-1 or resveratrol treatment reversed these effects. LPS+AGEs upregulated pIKBα and pNF-κB p65 expression in osteocytes, and resveratrol or ferrostatin-1 reversed this effect. In conclusion, diabetic periodontitis triggers alveolar osteocyte ferroptosis possibly via disruption of the SLC7A11/GPX4 axis, and resveratrol has therapeutic potential to correct this biological event.
The Lujiatun Unit of the Yixian Formation yields the only three-dimensionally preserved fossils from the Early Cretaceous Jehol Biota and crops out only in western Liaoning. Here, we report a new ...fossil site for the Jehol Biota with three-dimensionally preserved fossils from Ningcheng, Inner Mongolia. The fossils that have been discovered at this new site are predominantly dinosaurs and include a Sinovenator-like troodontid skeleton, three isolated sauropod teeth, some disarticulated skeletons of neornithischians and ceratopsians, and fragmentary lower jaws from a lizard and a mammal. The faunal composition, as well as the lithological features of the fossil beds, are comparable with those of the Lujiatun Unit of the Yixian Formation at Beipiao, western Liaoning, China. This discovery expands the geographical range of the Lujiatun-like dinosaurian assemblage of the Jehol Biota, and increases the biodiversity of the Jehol Biota in the Ningcheng Basin, China.
Defect detection is one of the key factors in fabric quality control. To improve the speed and accuracy of denim fabric defect detection, this paper proposes a defect detection algorithm based on ...cascading feature extraction architecture. Firstly, this paper extracts these weight parameters of the pre-trained VGG16 model on the large dataset ImageNet and uses its portability to train the defect detection classifier and the defect recognition classifier respectively. Secondly, retraining and adjusting partial weight parameters of the convolution layer were retrained and adjusted from of these two training models on the high-definition fabric defect dataset. The last step is merging these two models to get the defect detection algorithm based on cascading architecture. Then there are two comparative experiments between this improved defect detection algorithm and other feature extraction methods, such as VGG16, ResNet-50, and Xception. The results of experiments show that the defect detection accuracy of this defect detection algorithm can reach 94.3% and the speed is also increased by 1-3 percentage points.
The Saima alkaline rock-hosted niobium–tantalum deposit (hereafter referred to as the Saima Deposit) is situated in the Liaodong Peninsula, which constitutes the eastern segment of the northern ...margin of the North China Craton. The rock types of the Saima Deposit include phonolite, nepheline syenite, and aegirine nepheline syenite, which hosts niobium–tantalum ore bodies. In this study, the primary niobium-bearing minerals identified include loparite, betafite, and fersmite. The Saima pluton is characterized as a potassium-rich, low-sodium, and peraluminous alkaline pluton. Trace element characteristics reveal that the metallization-associated syenite is enriched in large-ion lithophile elements (LILEs) such as K and Rb but is relatively depleted in high-field strength elements (HFSEs). As indicated by the rare earth element (REE) profile, the Saima pluton exhibits a high total REE content (∑REE), dominance of light REEs (LREEs), and scarcity of heavy REEs (HREEs). The Sr-Nd-Pd isotopic data suggest that aegirine nepheline syenite and nepheline syenite share consistent isotopic signatures, indicating a common origin. The Saima alkaline pluton displays elevated ISr values ranging from 0.70712 to 0.70832 coupled with low εNd(t) values between −12.84 and −11.86 and two-stage model ages (tDM2) from 1967 to 2047 Ma. These findings indicate that the metallogenic materials for the Saima Deposit derive from both an enriched mantle source and some crustal components. The lithium (Li) isotopic fractionation observed during the genesis of the Saima pluton could be attributed to the differential diffusion rates of 6Li and 7Li under non-equilibrium fluid–rock interactions.
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