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991.
992.
阐述了PVA纤维的性能特点以及其在混凝土材料中的应用情况。综述了PVA增强混凝土材料的力学性能以及微观结构,分析了目前在工程应用中存在的问题,提出了该课题研究的必要性。 相似文献
993.
Sun Yukun Huo Pengju Wang Yujie Cui Ziqi Li Yang Dai Baisheng Li Runze Zhang Yonggen 《Journal of dairy science》2019,102(11):10140-10151
Body condition score (BCS) is a common tool for indirectly estimating the mobilization of energy reserves in the fat and muscle of cattle that meets the requirements of animal welfare and precision livestock farming for the effective monitoring of individual animals. However, previous studies on automatic BCS systems have used manual scoring for data collection, and traditional image extraction methods have limited model performance accuracy. In addition, the radio frequency identification device system commonly used in ranching has the disadvantages of misreadings and damage to bovine bodies. Therefore, the aim of this research was to develop and validate an automatic system for identifying individuals and assessing BCS using a deep learning framework. This work developed a linear regression model of BCS using ultrasound backfat thickness to determine BCS for training sets and tested a system based on convolutional neural networks with 3 channels, including depth, gray, and phase congruency, to analyze the back images of 686 cows. After we performed an analysis of image model performance, online verification was used to evaluate the accuracy and precision of the system. The results showed that the selected linear regression model had a high coefficient of determination value (0.976), and the correlation coefficient between manual BCS and ultrasonic BCS was 0.94. Although the overall accuracy of the BCS estimations was high (0.45, 0.77, and 0.98 within 0, 0.25, and 0.5 unit, respectively), the validation for actual BCS ranging from 3.25 to 3.5 was weak (the F1 scores were only 0.6 and 0.57, respectively, within the 0.25-unit range). Overall, individual identification and BCS assessment performed well in the online measurement, with accuracies of 0.937 and 0.409, respectively. A system for individual identification and BCS assessment was developed, and a convolutional neural network using depth, gray, and phase congruency channels to interpret image features exhibited advantages for monitoring thin cows. 相似文献
994.
Multimedia Tools and Applications - Image registration is a crucial step in the field of computer vision. However, the traditional scale invariant feature transform (SIFT) based method often... 相似文献
995.
Chaojun Cui Ye Wang Xiangze Du Li Li Mouxiao Song Wenqing Zeng Guiying Li Changwei Hu 《International Journal of Hydrogen Energy》2021,46(40):20835-20847
xNi/HTASAO5 catalysts (x = 2.5, 3.3, 4.4, 5.8, 8.2) were prepared for CO2 reforming of methane. No crystalline nickel species formed on the catalysts with lower nickel content (≤4.4%), and large Ni0 crystallite formed on 5.8% (10 nm) and 8.2 wt%Ni/HTASAO5 (17 nm), whereas the surface concentration of Ce3+ decreased with Ni loading. The initial conversion of CH4 increased from 29.5% to 46.9% with Ni loading. The xNi/HTASAO5 (x ≤ 4.4%) performed stably in the reaction due to the presence of dispersed Ni species and high surface Ce3+ content without coke formation, however, 5.8% and 8.2 wt%Ni/HTASAO5 exhibited decreased activity with time on stream, because of the formation of large Ni particles with lower surface Ce3+, leading to carbon accumulation. Thus, CH4 conversion stabilized at about 43% and no carbon formed on 4.4 wt%Ni/HTASAO5 with optimum Ni loading. 相似文献
996.
In this work, the needled carbon fiber preforms were used to make seven groups of carbon/carbon composite billets with different matrix carbon contents by controlling the processing time of chemical vapor infiltration (CVI). Cf/C–SiC composites were prepared by infiltration of SiC into these C/C composites billets using polycarbosilane (PCS) through precursor infiltration and pyrolysis (PIP). After oxy-acetylene torch testing (heat flux of 4.2 MW/m2) for 200s, 300s and 400s, respectively, it revealed that the anti-ablation properties of the Cf/C–SiC composite samples were enhanced by a higher content of SiC matrix. Additionally, specimens bearing longer duration tests showed a trend of lower average ablation rates. The lowest linear ablation rate is 0.008 mm/s and the mass ablation rate is 0.0019 g/s for those high SiC content samples tested for 400s. The SEM images of the tested samples showed the mechanism and the non-linear process of ablation resistance progression. 相似文献
997.
Qi Zhang Shihui Jiao Boran Wang Zisheng Wang Xinyan Lv Wenwen Wang Yumei Tan Canyu Cui Yan Chen 《International Journal of Hydrogen Energy》2021,46(52):26329-26339
Electrocatalytic water splitting for hydrogen production plays a vital role in the development of new energy field, but there is still a lack of low-content precious metal or cost-effective non-noble metal catalysts for the hydrogen evolution reaction (HER). Therefore, how to develop the catalysts with a smaller amount of precious metal to achieve higher performance is still a major challenge. Herein, we have fabricated Ru–Ni2P@Ni(OH)2/NF-2 heterostructure by phosphating Ni(OH)2/NF and then anchoring Ru on the surface through wet chemical strategy. Benefiting from its optimal ΔGH1 and synergistic effect, this Ru–Ni2P@Ni(OH)2/NF-2 catalyst shows superior electrocatalytic HER kinetics in alkaline electrolyte. A small overpotential of 31 mV is needed for this electrocatalyst to obtain the current densities of 10 mA cm?2 with remarkable durability over 24 h. This work provides a new strategy for the preparation of effective HER electrocatalyst with a low precious metal content. 相似文献
998.
999.
Luo Siyu Wu Yuxian Wen Zhiwei Cui Yajing Zhao Yong Chen Yongliang 《Journal of Superconductivity and Novel Magnetism》2022,35(9):2319-2325
Journal of Superconductivity and Novel Magnetism - (Li0.8Fe0.2)OHFeSe is a superconductor with high superconducting transition temperature (43 K) and stable in air, which is conducive to... 相似文献
1000.
Kuang Kun Li Yunzhe Li Bo Cui Peng Yang Hongxia Tao Jianrong Wu Fei 《Data mining and knowledge discovery》2021,35(6):2467-2497
Data Mining and Knowledge Discovery - One fundamental problem in causal inference is the treatment effect estimation in observational studies, and its key challenge is to handle the confounding... 相似文献