106 research outputs found

    Vibration control of a tunnel boring machine using adaptive magnetorheological damper

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    With a large number of tunnel boring machines (TBM) being used in various tunnel constructions, the vibration problem under complex geological conditions have become increasingly prominent. In order to solve the problem, this article investigates the application of an adaptive magnetorheological (MR) damper on the vibration reduction of a TBM. The MR damper could reduce the horizontal vibration of the TBM system and adjust its dragging force on the propulsive system under different geological conditions. The MR damper can also provide large enough damping force even under a small amplitude vibration, which is required by TBM. In this paper, an MR damper was designed, prototyped and its properties were tested by an MTS system, including its current-dependency, amplitude-dependency and frequency-dependency features. A scaled TBM system incorporated with the MR damper was built to evaluate the vibration reduction effectiveness of the MR damper on the TBM system. The experimental test results demonstrate that the displacement and the acceleration amplitudes of the TMB vibration could be reduced by 52.14% and 53.31%, respectively

    Expression of aquaporin 5 in primary carcinoma and lymph node metastatic carcinoma of non‑small cell lung cancer

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    Aquaporin 5 (AQP5), a water channel protein, is highly expressed in non‑small cell lung cancer (NSCLC) tissues compared with adjacent normal tissues. AQP5 expression in lung cancer tissues is associated with a poor prognosis. The present study aimed to analyze the expression of AQP5 and investigate its role in primary and lymph node metastatic NSCLCs. An immunohistochemical labeled streptavidin-biotin method was used to determine the expression of AQP5 in 94 cases of NSCLC primary carcinoma, which included 51 cases accompanied by lymph node metastasis. The results revealed that the expression of AQP5 was significantly higher in adenocarcinomas compared with squamous cell carcinomas (P=0.002). In addition, the percentage of AQP5 expression in the primary carcinomas with lymph node metastasis was significantly higher compared with those without lymph node metastasis (P=0.024). However, no statistically significant difference in the percentage of AQP5 expression was observed between the metastatic and the primary carcinomas (P=0.377). The expression of AQP5 exhibited a correlation with the tumor‑node‑metastasis staging of NSCLC (P=0.027). The percentage of AQP5 expression in stage III and IV tumors was higher than that in stage I and II tumors. In addition, AQP5 expression was correlated with the survival rate of NSCLC patients (P=0.051). In conclusion, the results of the present study provide evidence for the AQP5‑facilitated incidence, progression and metastasis of NSCLC.published_or_final_versio

    Evaluation of precipitable water vapor from five reanalysis products with ground-based GNSS observations

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    At present, the global reliability and accuracy of Precipitable Water Vapor (PWV) from different reanalysis products have not been comprehensively evaluated. In this study, PWV values derived by 268 Global Navigation Satellite Systems (GNSS) stations around the world covering the period from 2016 to 2018 are used to evaluate the accuracies of PWV values from five reanalysis products. The temporal and spatial evolution is not taken into account in this analysis, although the temporal and spatial evolution of atmospheric flows is one of the most important information elements available in numerical weather prediction products. The evaluation results present that five reanalysis products with PWV accuracy from high to low are in the order of the fifth generation of European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis (ERA5), ERA-Interim, Japanese 55-year Reanalysis (JRA-55), National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), and NCEP/DOE (Department of Energy) according to root mean square error (RMSE), bias and correlation coefficient. The ERA5 has the smallest RMSE value of 1.84 mm, while NCEP/NCAR and NCEP/DOE have bigger RMSE values of 3.34 mm and 3.51 mm, respectively. The findings demonstrate that ERA5 and two NCEP reanalysis products have the best and worst performance, respectively, among five reanalysis products. The differences in the accuracy of the five reanalysis products are mainly attributed to the differences in the spatial resolution of reanalysis products. There are some large absolute biases greater than 4 mm between GNSS PWV values and the PWV values of five reanalysis products in the southwest of South America and western China due to the limit of terrains and fewer observations. The accuracies of five reanalysis products are compared in different climatic zones. The results indicate that the absolute accuracies of five reanalysis products are highest in the polar regions and lowest in the tropics. Furthermore, the effects of different seasons on the accuracies of five reanalysis products are also analyzed, which indicates that RMSE values of five reanalysis products in summer and in winter are the largest and the smallest in the temperate regions. Evaluation results from five reanalysis products can help us to learn more about the advantages and disadvantages of the five released water vapor products and promote their applications.Peer ReviewedPostprint (published version

    Development and evaluation of a versatile semi-active suspension system for high-speed railway vehicles

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    With the increase in speed of high-speed trains, their vibration will become fiercer and fiercer, especially when the lateral resonance of the car body occurs. This paper develops a versatile semi-active suspension system with variable stiffness (VS) magnetorheological elastomer (MRE) isolators and variable damping (VD) magnetorheological (MR) dampers for high-speed trains, aiming to improve ride comfort by avoiding car body resonance and dissipating vibration energy. As the first step, a multifunction VSVD semi-active suspension system for high-speed railway vehicles was designed and prototyped, including four VS-MRE isolators and two VD-MR dampers. After that, a scaled train model, composing of a car body and a secondary lateral suspension system was designed and built to evaluate the performance of the new VSVD suspension system; a control strategy based on short-time Fourier transform (STFT) and sky-hook was proposed to control the new suspension system. Two different excitations, harmonic excitation and random excitation, were applied to evaluate the train\u27s VSVD suspension. As a comparison, four alternative suspension systems, including passive-off suspension, passive-on suspension, pure VS suspension, and pure VD suspension were also evaluated. The evaluation results verified that the VSVD suspension of the train can avoid lateral resonance of car body and dissipate the vibration energy efficiently. The comparison verified that the VSVD suspension system outperforms the passive-off suspension, passive-on suspension, pure VS suspension, and pure VD suspension

    Light adaptation strategies of Quercus mongolica at different ages in four plantations

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    This study investigated the allocation strategies of non-structural carbohydrates and functional traits in Quercus mongolica seedlings of different ages under different light conditions. The study took place at the Urban Forestry Demonstration Base in Harbin City, Heilongjiang Province, China. Seedlings of three age classes were collected in two light environments, the forest edge and the forest understory. By measuring specific leaf area, biomass, soluble sugar concentration and starch concentration, we revealed the growth adaptation strategies and responses to different light conditions in Q. mongolica seedlings of different age classes. Our results show that the adaptation strategies of seedlings of different age classes are very different. First, our study showed a strong coordination of soluble sugars between roots, stems, and leaves of 1−2 year old Q. mongolica seedlings, indicating an efficient partitioning of carbon between organs at this age. In 3−4 year old Q. mongolica seedlings, a significant negative correlation was observed between starch in the roots and soluble sugars in the leaves, indicating the transformation of various non-structural carbohydrates. In addition, 5−6 year old seedlings start to increase their investment in the above-ground part to achieve a height advantage. In conclusion, this study improves our understanding of the light adaptation strategies of Q. mongolica seedlings and provides valuable insights for the natural regeneration and management of Q. mongolica forest vegetation

    Visual In-Context Prompting

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    In-context prompting in large language models (LLMs) has become a prevalent approach to improve zero-shot capabilities, but this idea is less explored in the vision domain. Existing visual prompting methods focus on referring segmentation to segment the most relevant object, falling short of addressing many generic vision tasks like open-set segmentation and detection. In this paper, we introduce a universal visual in-context prompting framework for both tasks. In particular, we build on top of an encoder-decoder architecture, and develop a versatile prompt encoder to support a variety of prompts like strokes, boxes, and points. We further enhance it to take an arbitrary number of reference image segments as the context. Our extensive explorations show that the proposed visual in-context prompting elicits extraordinary referring and generic segmentation capabilities to refer and detect, yielding competitive performance to close-set in-domain datasets and showing promising results on many open-set segmentation datasets. By joint training on COCO and SA-1B, our model achieves 57.757.7 PQ on COCO and 23.223.2 PQ on ADE20K. Code will be available at https://github.com/UX-Decoder/DINOv.Comment: technical repor

    Application and development of Deuterium Metabolic Imaging in tumor glucose metabolism: visualization of different metabolic pathways

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    Cancer metabolism has emerged as a pivotal area of research recently. The ability to visualize and comprehend the metabolic processes of cancer holds immense clinical value, particularly in the diagnosis of malignant tumors and the assessment of treatment responses. Deuterium Metabolic Imaging (DMI), as a robust, simple, and versatile MR spectroscopic imaging tool, demonstrates promise in tumor diagnosis and treatment efficacy assessment. This review explored the latest developments and applications of DMI in oncology across various tumor metabolic axes, with a specific emphasis on its potential for clinical translation. DMI offers invaluable insights into tumor biology, treatment responses, and prognostic outcomes. Notably, DMI can identify early responses to immunotherapy, a prominent area of current research interest. In conclusion, DMI harbors the potential to evolve into a convenient and efficient imaging technique in clinical practice, thereby advancing precision medicine and improving the diagnosis and evaluation of cancer treatments

    detrex: Benchmarking Detection Transformers

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    The DEtection TRansformer (DETR) algorithm has received considerable attention in the research community and is gradually emerging as a mainstream approach for object detection and other perception tasks. However, the current field lacks a unified and comprehensive benchmark specifically tailored for DETR-based models. To address this issue, we develop a unified, highly modular, and lightweight codebase called detrex, which supports a majority of the mainstream DETR-based instance recognition algorithms, covering various fundamental tasks, including object detection, segmentation, and pose estimation. We conduct extensive experiments under detrex and perform a comprehensive benchmark for DETR-based models. Moreover, we enhance the performance of detection transformers through the refinement of training hyper-parameters, providing strong baselines for supported algorithms.We hope that detrex could offer research communities a standardized and unified platform to evaluate and compare different DETR-based models while fostering a deeper understanding and driving advancements in DETR-based instance recognition. Our code is available at https://github.com/IDEA-Research/detrex. The project is currently being actively developed. We encourage the community to use detrex codebase for further development and contributions.Comment: project link: https://github.com/IDEA-Research/detre
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