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Gearbox fault diagnosis of rolling mills using multiwavelet sliding window neighboring coefficient denoising and optimal blind deconvolution

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Science China(Technological Sciences) 2009年第10期52卷 2801-2809页

作者： YUAN Jing HE ZhengJia ZI YanYang liu han State Key Laboratory for Manufacturing Systems Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China Shanghai Baosteel Industry Inspection Corporation Baosteel Group CorporationShanghai 200122China

Fault diagnosis of rolling mills, especially the main drive gearbox, is of great importance to the high quality products and long-term safe operation. However, the useful fault information is usually submerged in heavy background noise under the severe condition. Thereby, a novel method based on multiwavelet sliding window neighboring coefficient denoising and optimal blind deconvolution is proposed for gearbox fault diagnosis in rolling mills. The emerging multiwavelets can seize the important signal processing properties simultaneously. Owing to the multiple scaling and wavelet basis functions, they have the supreme possibility of matching various features. Due to the periodicity of gearbox signals, sliding window is recommended to conduct local threshold denoising, so as to avoid the "overkill" of conventional universal thresholding techniques. Meanwhile, neighboring coefficient denoising, considering the correlation of the coefficients, is introduced to effectively process the noisy signals in every sliding window. Thus, multiwavelet sliding window neighboring coefficient denoising not only can perform excellent fault extraction, but also accords with the essence of gearbox fault features. On the other hand, optimal blind deconvolution is carried out to highlight the denoised features for operators' easy identification. The filter length is vital for the effective and meaningful results. Hence, the foremost filter length selection based on the kurtosis is discussed in order to full benefits of this technique. The new method is applied to two gearbox fault diagnostic cases of hot strip finishing mills, compared with multiwavelet and scalar wavelet methods with/without optimal blind deconvolution. The results show that it could enhance the ability of fault detection for the main drive gearboxes.

关键词： multiwavelet denoising blind deconvolution gearbox fault diagnosis rolling mill

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Distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in surface water and sediments from Baiyangdian Lake in North China

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Journal of Environmental Sciences 2011年第10期23卷 1640-1649页

作者： Guohua Dai Xinhui liu Gang Liang Xu han liu Shi Dengmiao Cheng Wenwen Gong State Key Laboratory of Water Environment Simulation School of Environment Beifing Normal University Beifing 100875 China

Persistent organochlorine compounds, including hexachlorocyclohexanes （HCHs）, dichlorodiphenyltrichloroethanes （DDTs） and polychlorinated biphenyls （PCBs） were analyzed in surface water and sediments from Balyangdian Lake, North China. Total concentrations of HCHs, DDTs and PCBs in surface water were in the range of 3.13-10.60, 4.05-20.59 and 19.46-131.62 ng/L, respectively, and total concentrations of HCHs, DDTs and PCBs in sediments were 1.75-5.70, 0.91-6.48 and 5.96-29.61 ng/g dry weight, respectively. Among the groups of HCHs （sum of α-HCH, β-HCH, y-HCH and 6-HCH） and DDTs （sum of DDT, DDD and DDE）, the predominance of β-HCH, DDE and DDD in water and sediment samples was clearly observed. This observation suggested that β-HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD. For PCBs, penta-, hexa- and hepta-chlorinated congeners were the most abundant compounds in the both phases. Furthermore, the partitioning of chlorinated compounds between sediment and water was investigated to understand their transport and fates in aquatic ecosystems. The results indicated that average logs of organic carbon-normalized sediment-water partition coefficients （logK∝） for OCPs varied between 3.20 and 5.53, and for PCBs, logK∝ values ranged from 3.19 to 5.57. The observed logK∝ was lower than their equilibrium logK∝ predicted from linear model, which may be attributed to the solubility enhancement effect of colloidal matter in water phase and the disequilibrium between sediment and water.

关键词： oranochlorine pesticides polychlorinated biphenyls water sediment Baiyangdian Lake North China

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Neural-mechanism-driven image block encryption algorithm incorporating a hyperchaotic system and cloud model

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Chinese Physics B 2022年第4期31卷 175-190页

作者： Peng-Fei Fang han liu Cheng-Mao Wu Min liu School of Automation and Information Engineering Xi’an University of TechnologyXi’an 710048China School of Electronic Engineering Xi’an University of Posts&TelecommunicationsXi’an 710061China School of Engineering and Computer Science Australian National UniversityCanberra 0200Australia

An image encryption algorithm is proposed in this paper based on a new four-dimensional hyperchaotic system,a neural mechanism,a Galois field and an improved Feistel block structure,which improves the efficiency and enhances the security of the encryption ***,a four-dimensional hyperchaotic system with a large key space and chaotic dynamics performance is proposed and combined with a cloud model,in which a more complex and random sequence is constructed as the key stream,and the problem of chaotic periodicity is ***,the key stream is combined with the neural mechanism,Galois field and improved Feistel block structure to scramble and diffuse the image ***,the experimental results and security analysis show that the encryption algorithm has a good encryption effect and high encryption efficiency,is secure,and can meet the requirements of practical applications.

关键词： image encryption neural mechanism hyperchaotic system

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Iron-Doped Titania Nanoparticles for the Photocatalytic Oxidative Degradation of Nitrite

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Chemical Research in Chinese Universities 2001年第3期17卷 281-286页

作者： XU An-wu ZHU Jing-yan GAO Yuan liu han-qin School of Chemistry and Chemical Engineering Zhongshan UniversityGuangzhou 510275P.R.China

Iron-doped titania nanoparticles exhibit a higher photocatalytic activity than pure TiO_2 for the degradation of nitrite. The optimum Fe-doped content in terms of activity is approximately 0.5%. The increase in photoactivity is probably due to the higher adsorption and the inhibition of electron-hole recombination. The photocatalytic oxidation reaction of nitrite over the Fe-doped TiO_2 catalyst follows zero-order kinetics, which is different from that over pure TiO_2. The reaction rate decreases linearly with the increase of the pH of the solution.

关键词： Nitrite degradation Photocatalytic oxidation Titania Iron doped

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3D stability analysis method of concave slope based on the Bishop method

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International Journal of Mining Science and Technology 2017年第2期27卷 365-370页

作者： Zhang Tianwen Cai Qingxiang han liu Shu Jisen Zhou Wei School of Mines China University of Mining and TechnologyXuzhou 221116China Xiaolongtan Mining Administration Kaiyuan 661699China

In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop method was employed. The sliding body was divided into strips in a three-dimensional model, and the lateral earth pressure was put into mechanical analysis and the three-dimensional stability analysis methods applicable for circular sliding in concave slope were deduced. Based on geometric structure and the geological parameters of a concave slope, the influence rule of curvature radius and the top and bottom arch height on the concave slope stability were analyzed. The results show that the stability coefficient decreases after growth, first in the transition stage of slope shape from flat to concave, and it has been confirmed that there is a best size to make the slope stability factor reach a maximum. By contrast with average slope, the stability of a concave slope features a smaller range of ascension with slope height increase, which indicates that the enhancing effect of a concave slope is apparent only with lower slope heights.

关键词： Bishop method Concave slope Three-dimensional structure Stability analysis

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Two-channel model based adaptive schlieren detection algorithm for BOS system

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Journal of Systems Engineering and Electronics 2019年第2期30卷 251-258页

作者： liu han ZhanG Yanmei ZHAO Baojun GUO Haichao ZHAO Boya School of Information and Electronics Beijing Institute of Technology National Key Laboratory of Science and Technology on Space Microwave China Academy of Space Technology

A schlieren detection algorithm is proposed for the ground-to-air background oriented schlieren(BOS) system to achieve high-speed airplane shock waves visualization. The proposed method consists of three steps. Firstly, image registration is incorporated for reducing errors caused by the camera ***, the background subtraction dual-model single Gaussian model(BS-DSGM) is proposed to build a precise background model. The BS-DSGM could prevent the background model from being contaminated by the shock waves. Finally, the twodimensional orthogonal discrete wavelet transformation is used to extract schlieren information and averaging schlieren data. Experimental results show our proposed algorithm is able to detect the aircraft in-flight and to extract the schlieren information. The precision of schlieren detection algorithm is 0.96. Three image quality evaluation indices are chosen for quantitative analysis of the shock waves visualization. The white Gaussian noise is added in the frames to validate the robustness of the proposed ***, we adopt two times and four times down sampling to simulate different imaging distances for revealing how the imaging distance affects the schlieren information in the BOS system.

关键词： background model background oriented schlieren (BOS) schlieren detection wavelet decomposition

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ENUMERATION OF ROOTED PLANAR HALIN MAPS

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Applied Mathematics(A Journal of Chinese Universities) 1999年第1期14卷 117-121页

作者： Ren han\ liu Yanpei Dept. of Math. Northern Jiaotong Univ. Beijing

Abstract A Halin map is a kind of planar maps oriented by a tree. In this paper the rooted halin maps with the vertex partition as parameters are enumerated such that a famous result on rooted trees due to Harary, Prins, and Tutte is deduced as a special case. Further, by using Lagrangian inversion to obtain a number of summation free formulae directly, the various kinds of rooted Halin maps with up to three parameters have been counted.

关键词： 1991 MR Subject Classification 05C45

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Pore-based architecture and representative element volume evaluation in artificial sand packs and natural rock cores

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Petroleum Science 2022年第4期19卷 1473-1482页

作者： Peng-Fei Lv Yu liu Feng liu Wen-Zhe Yang han-Tao liu Bo Zhang Yong-Chen Song School of Energy and Power Engineering North University of ChinaTaiyuanShanxi030051China Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of TechnologyDalianLiaoning116024China Tianjin Refrigeration Technology Key Laboratory Tianjin University of CommerceTianjin300134China School of Chemical and Biological Engineering Taiyuan University of Science and TechnologyTaiyuanShanxi030024China

The phenomenon of multiphase flow in porous media is confronted in various fields of science and industrial applications. Owing to the complicated porous structure, the flow mechanisms are still not completely resolved. A critical and fundamental question is the variation of pore structure and REV sizes among different types of porous media. In this study, a total of 22 porous samples were employed to systematically evaluate the pore-based architecture and REV sizes based on X-ray CT image analysis and pore network modelling. It is found that the irregular grain shapes give rise to large specific areas,narrow and thin throats in identical sand packs. The packs with more types of sands, or composited by the sands with larger difference in diameter, have larger specific area, smaller tortuosity and pore *** on the REV measurement through porosity solely, the REV sizes of sand packs are generally in the order of magnitude of 10^(-2) m L, while it is at least one order of magnitude smaller in rock cores. Our result indicates that the combination of porosity and Euler number is an effective indicator to get the REV sizes of porous samples.

关键词： Pore structure REV Sand pack Rock core Pore network modelling

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Organoid extracellular vesicle-based therapeutic strategies for bone therapy

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Biomaterials Translational 2023年第4期4卷 199-212页

作者： han liu Jiacan Su Institute of Translational Medicine Shanghai UniversityShanghaiChina Organoid Research Center Shanghai UniversityShanghaiChina National Center for Translational Medicine(Shanghai)SHU Branch Shanghai UniversityShanghaiChina Department of Orthopedics Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghaiChina

With the rapid development of population ageing,bone-related diseases seriously affecting the life of the *** the past few years,organoids,cell clusters with specific functions and structures that are self-induced from stem cells after three-dimensional culture in vitro,have been widely used for bone ***,organoid extracellular vesicles(OEVs)have emerging as promising cell-free nanocarriers due to their vigoroso physiological effects,significant biological functions,stable loading capacity,and great *** this review,we first provide a comprehensive overview of biogenesis,internalisation,isolation,and characterisation of *** then comprehensively highlight the differences between OEVs and traditional ***,we present the applications of natural OEVs in disease *** also summarise the engineering modifications of OEVs,including engineering parental cells and engineering OEVs after ***,we provide an outlook on the potential of natural and engineered OEVs in bone-related ***,we critically discuss the advantages and challenges of OEVs in the treatment of bone *** believe that a comprehensive discussion of OEVs will provide more innovative and efficient solutions for complex bone diseases.

关键词： bone therapy engineering modifications extracellular vesicles nanotechnology organoid extracellular vesicles

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Geochronology, Geochemistry, and Sr–Nd–Hf Isotopes of the Balazha Ore-Bearing Porphyries： Implications for Petrogenesis and Geodynamic Setting of Late Cretaceous Magmatic Rocks in the Northern Lhasa Block, Tibet

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Acta Geologica Sinica(English Edition) 2018年第5期92卷 1739-1752页

作者： liu Wei WANG Baodi YANG Xiaoyong YUAN Sihua liu han LIAO Zhongli CAS Key Laboratory of Crust-Mantle Materials and Environments University of Science and Technology of China Hefei 230026 China Chengdu Center China Geological Survey Chengdu 610081 China Institute of Disaster Prevention Sanhe 065201 HebeL China

The study of Late Cretaceous magmatic rocks, developed as a result of magmatism and related porphyry mineralization in the northern Lhasa block, is of significance for understanding the associated tectonic setting and mineralization. This paper reports zircon chronology, zircon Hf isotope data, wholerock Sr–Nd isotope data, and geochemistry data of Balazha porphyry ores in the northern Lhasa block. Geochemical features show that Balazha ore-bearing porphyries in the northern Lhasa block belong to high-Mg# adakitic rocks with a formation age of ～90 Ma; this is consistent with the Late Cretaceous magmatic activity that occurred at around 90 Ma in the region. The age of adakitic rocks is similar to the molybdenite Re–Os model age of the ore-bearing porphyries in the northern Lhasa block, indicating that the diagenesis and mineralization of both occurred during the same magmatism event in the Late Cretaceous. The Hf and Sr–Nd isotope data indicate that these magmatic rocks are the product of crust–mantle mixing. Differing proportions of materials involved in such an event form different types of medium-acid rocks, including ore-bearing porphyries. Based on regional studies, it has been proposed that Late Cretaceous magmatism and porphyry mineralization in the northern Lhasa block occurred during collision between the Lhasa and Qiangtang blocks.

关键词： adakitic rocks collision porphyry deposit Mesozoic Tibet

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