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  • IOP Publishing  (30)
  • 1
    Online Resource
    Online Resource
    IOP Publishing ; 2023
    In:  Smart Materials and Structures Vol. 32, No. 3 ( 2023-03-01), p. 034001-
    In: Smart Materials and Structures, IOP Publishing, Vol. 32, No. 3 ( 2023-03-01), p. 034001-
    Abstract: In this paper, a new method integrating the improved singular spectrum analysis and the multiscale cross-sample entropy Improved Singular Spectrum Analysis and Multiscale Cross-Sample Entropy, (ISSA-MCSEn) is developed to identify the size of early damages in thin plate-like structures. In the algorithm, with the help of improved singular spectrum analysis (ISSA), the principal components relevant to the reference and damage-induced signals are successfully extracted, and then the components related to the damage are reconstructed for damage size detection. Lastly, the multiscale cross-sample entropy (MCSEn) of the reconstructed signal is computed as a new damage index to evaluate the size of the damage. To validate the proposed ISSA-MCSEn algorithm, two different experiments are conducted on aluminum and composite fiber reinforced polymer (CFRP) plates to detect simulated crack and through-hole, respectively. Comparative performance analysis of ISSA and singular spectrum analysis (SSA) demonstrates that the total increment of the normalized MCSEn by using ISSA is 30%–81% while the one by using SSA is only 6.5%–9%, which demonstrates that the performance of the proposed ISSA is much better than SSA. The experimental results also show that the average of the normalized MCSEn of the proposed algorithm increases by over 77% and 28% as the size of the two damages in CFRP and aluminum plates changes from 0 to 8 mm and 0 to 1.2 mm, respectively. Moreover, the relationship between the normalized MCSEn and damages’ size is well linear, and the Pearson’s coefficient of their fitting curves is more than 0.99, which demonstrates that this linear relationship can be employed for damage size detection in both CRFP and aluminum plates. The linear relationship between the damage size and normalized MCSEn is used for damage detection, and the relative error between the actual and detected size is 1.64%–6.92%. In addition, the performance comparison of ISSA-MCSEn and SSA-FuzzyEn shows that the total increment of the ISSA-MCSEn algorithm due to the damage is 30%–81% while the one of SSA-FuzzyEn is only 4%–15%, which indicates that the proposed ISSA-MCSEn is more sensitive to the damage than SSA-FuzzyEn and it is more suitable for detection of small-size damages.
    Type of Medium: Online Resource
    ISSN: 0964-1726 , 1361-665X
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 1115038-5
    detail.hit.zdb_id: 2002821-0
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  • 2
    Online Resource
    Online Resource
    IOP Publishing ; 2019
    In:  IOP Conference Series: Earth and Environmental Science Vol. 300, No. 3 ( 2019-07-01), p. 032112-
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 300, No. 3 ( 2019-07-01), p. 032112-
    Abstract: Due to man-made damage, plant diseases and insect pests, environmental greening, ecological environment and other reasons, ancient and famous trees have been severely damaged. The protection of ancient trees requires diagnosis of their health and biological and chemical treatment measures. Aiming at the inconvenience, high cost and low degree of automation of manual methods for health diagnosis of ancient trees, the solution and overall architecture of a tree health diagnosis system based on OpenCV and genetic algorithm are analyzed and designed. Firstly, the leaf image mode is trained, and the color histogram is used to distinguish the leaf density and color difference between different individuals, and the fitting index is used to obtain more accurate diagnostic classification standards. Then, the matching value is calculated by genetic algorithm training through the H average value in HSVHSV and the H average value of healthy ancient trees in the histogram to obtain the matching grade. Then, the tree image is read, artificial segmentation is carried out to obtain the quasi-healthy crown score, weighted summation is carried out to obtain the leaf score, and the health grade is separated according to the ratio. Finally, the two are weighted to obtain the final health grade. The experimental results show that the system can accurately and effectively distinguish different leaf health grades according to the difference of leaf color and density, and provide quantitative data for health diagnosis research of ancient and famous trees.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2019
    detail.hit.zdb_id: 2434538-6
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  • 3
    Online Resource
    Online Resource
    IOP Publishing ; 2019
    In:  IOP Conference Series: Earth and Environmental Science Vol. 218 ( 2019-02-24), p. 012162-
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 218 ( 2019-02-24), p. 012162-
    Type of Medium: Online Resource
    ISSN: 1755-1315
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2019
    detail.hit.zdb_id: 2434538-6
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  • 4
    In: Environmental Research Letters, IOP Publishing, Vol. 4, No. 4 ( 2009-10), p. 045206-
    Type of Medium: Online Resource
    ISSN: 1748-9326
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2009
    detail.hit.zdb_id: 2255379-4
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  • 5
    Online Resource
    Online Resource
    IOP Publishing ; 2019
    In:  IOP Conference Series: Materials Science and Engineering Vol. 605, No. 1 ( 2019-08-01), p. 012001-
    In: IOP Conference Series: Materials Science and Engineering, IOP Publishing, Vol. 605, No. 1 ( 2019-08-01), p. 012001-
    Abstract: The gasification test was carried out with pine particle as raw material, how temperature and steam flow rate affect gas gasification performance index was studied by using self-made gasification test system platform. The results show that the volume fraction of hydrogen increases, the volume percentage of carbon monoxide decreases and CH4 content decreases with the increase of temperature in steam flow rate of 0.3kg/h; Its the gas volume fraction of the trend is similar with the steam flow rate of 0.3kg/h, but the total gas energy with the temperature increased first and then reduced and the total gas increased by 28393.39KJ/Kg at 800 °C; The steam flow from 0.3kg/h to 0.6kg/h, the low calorific value of gas varies from 10 to14MJ/m 3 , the increase of the calorific value of gas is 2111. 36KJ/m 3 .
    Type of Medium: Online Resource
    ISSN: 1757-8981 , 1757-899X
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2019
    detail.hit.zdb_id: 2506501-4
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  • 6
    Online Resource
    Online Resource
    IOP Publishing ; 2020
    In:  IOP Conference Series: Materials Science and Engineering Vol. 729, No. 1 ( 2020-01-01), p. 012023-
    In: IOP Conference Series: Materials Science and Engineering, IOP Publishing, Vol. 729, No. 1 ( 2020-01-01), p. 012023-
    Abstract: When most oil fields have entered high water cut stage, the distribution of oil and water is more and more complex. Profile control and water shutoff is an important technology for water control and oil stabilization. Some types of water invasion in special reservoirs such as bottom water coning or edge water propelling in horizontal wells, water invasion in micro facture and big pore carry more challenges for profile control and water shutoff technology. Beyond that this technology is also affected by the plugging agent injection’s uncertainty and migration randomness. On the basis of earlier research, this paper introduces the plugging agent formulas, technology and field application of three types of technologies which are as follows, casing channeling treatment technology, water invasion plugging technology in interlayer and water invasion in horizontal well. The three types of fixed point sealing technology can achieve the accurate injection of shutoff agent and good results had obtained in site test.
    Type of Medium: Online Resource
    ISSN: 1757-8981 , 1757-899X
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2020
    detail.hit.zdb_id: 2506501-4
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  • 7
    Online Resource
    Online Resource
    IOP Publishing ; 2021
    In:  IOP Conference Series: Earth and Environmental Science Vol. 859, No. 1 ( 2021-09-01), p. 012096-
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 859, No. 1 ( 2021-09-01), p. 012096-
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2434538-6
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  • 8
    Online Resource
    Online Resource
    IOP Publishing ; 2023
    In:  Journal of Physics: Conference Series Vol. 2569, No. 1 ( 2023-08-01), p. 012002-
    In: Journal of Physics: Conference Series, IOP Publishing, Vol. 2569, No. 1 ( 2023-08-01), p. 012002-
    Abstract: Electric tractors as a kind of green agricultural machinery, in reducing carbon emissions, saving resources, and other aspects have outstanding advantages. Therefore, the development and research of electric tractors are of great significance. In this paper, a new dual-motor coupled drive system applicable to electric tractors is proposed, and the structure and transmission characteristics of the system are analyzed in conjunction with the tractor operation requirements. At the same time, the drive system model is built in MATLAB/Simulink environment for simulation and verification. Finally, hardware-in-the-loop experiments were conducted using the Speedgoat platform. The simulation and experimental results prove that the electric tractor with this dual-motor coupled drive system has better power performance. The economic performance is better compared with the single-motor drive system, and the whole vehicle range can be extended by 1.23 h.
    Type of Medium: Online Resource
    ISSN: 1742-6588 , 1742-6596
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 2166409-2
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  • 9
    In: Europhysics Letters, IOP Publishing, Vol. 135, No. 6 ( 2021-09-01), p. 68001-
    Abstract: Taking advantage of the birefringence of crystal, this paper proposes an effective optical system to detect the residual stress at the surface of toughened glass. A theoretical model based on matrix optics is built to describe the optical distribution of a probe light in the system, and the simulation outputs two complementary images whose mode patterns are determined by the phase delay arising from the surface-stress–induced birefringence. The experimental results confirm the simulation results that the mode pattern varies accordingly while the phase delay varies in 2 period. Features of interference fringes are extracted by dedicated image recognition algorithm and form their own feature data sets. Comparing the experimental data sets with the simulation ones, the phase delay of each experimental pattern can be deduced, so the stress of the sample point can be calculated. Our device's surface stress scanning results of toughened glass are very close to the commercial instrument SCALP-04's ones, with the relative deviation between them below 6%. Our system provides an efficient and simple way to measure present stress distribution on the surface of transparent materials, and owing to its fewer instruments involvement, broad detecting distance, and high signal-to-noise ratio, our system can be developed into integrated products. This method can also be applied in different materials such as high polymer, silicide, etc., where only the wavelength of the laser needs to be modified.
    Type of Medium: Online Resource
    ISSN: 0295-5075 , 1286-4854
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 1465366-7
    detail.hit.zdb_id: 165776-8
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  • 10
    Online Resource
    Online Resource
    IOP Publishing ; 2022
    In:  Smart Materials and Structures Vol. 31, No. 3 ( 2022-03-01), p. 035015-
    In: Smart Materials and Structures, IOP Publishing, Vol. 31, No. 3 ( 2022-03-01), p. 035015-
    Abstract: In this research, a new method based on singular spectrum analysis (SSA) and fuzzy entropy is developed for damage detection on thin wall-like structures, and the normalized fuzzy entropy is employed as an indicator to identify the severity of the damage. The lead zirconate titanate (PZT) transducers are used in this research to generate and detect the Lamb waves. During the detection, the collected signals from the PZT sensors are firstly decomposed and reconstructed by SSA to extract the feature of the damage, and then the reconstructed signals with the feature of the damage are processed to obtain the normalized fuzzy entropy. An experimental setup of an aluminium plate with added magnets is fabricated to validate the proposed method. The experimental results show that when magnets are attached on the aluminium plate, the normalized fuzzy entropy is smaller than that when there are no magnets. That is because when magnets are placed on the plate, the movement and some vibration modes of Lamb waves are disturbed by the added magnets and this disturbing effect can be enhanced by increasing the number and locations of the added magnets, and eventually the complexity and nonlinearity of the waves are weakened. The experimental results of a single damage with different number of magnets indicate that the normalized fuzzy entropy decreases linearly as the number of the added magnets increases, which demonstrates that the proposed method can be used to detect the severity of the damage. Moreover, the experimental results of multi-damage on different locations indicate that the normalized fuzzy entropy is relevant with both the total number and locations of the added magnets. The normalized fuzzy entropy decreases linearly as the total number of the magnets increases, and the entropy of a single damage is smaller than that of the multi-damage with the same total number of magnets, which demonstrates that the proposed method also can be used for multi-damage detection on a thin plate. This study provides us a new approach to identifying a single or multiple damages on thin wall-like structures.
    Type of Medium: Online Resource
    ISSN: 0964-1726 , 1361-665X
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 1115038-5
    detail.hit.zdb_id: 2002821-0
    Location Call Number Limitation Availability
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