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Research progress on the development mechanism and exploratory protection of the scaling off on earthen sites in NW China

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Science China(Technological Sciences) 2023年第8期66卷 2183-2196页

作者： DU YuMin dong WenQiang CUI Kai CHEN WenWu YANG WeiLi Institute of Culture and Heritage Northwestern Polytechnical UniversityXi’an 710072China Western Center for Disaster Mitigation in Civil Engineering of Ministry of Education of China School of Civil EngineeringLanzhou University of TechnologyLanzhou 730050China Key Scientific Research Base of the State Administration of Cultural Heritage for the Conservation and Restoration of Murals and Material Science Research Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Mechanics on Disaster and Environment in Western China College of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China

The scaling off is among the most pervasive and severe deterioration *** scaling off developed on earthen sites in Northwest China has a special and complex binary structure composed of crusted and loose *** the synergistic functions of external environmental elements such as rainfall,temperature,and wind,and rammed earth properties,this deterioration has gradually created the crust on the site’s surface,and has then evolved into exfoliation and finally fallen off,leading to the reciprocating progressive destruction of earthen ***,determining the development mechanism of scaling off and implementing targeted protection measures for the scientific conservation of earthen sites has become *** this review study,the properties of the building material causing the binary structure and the coupling effects of water,temperature,salt,and wind on the development of scaling off were determined,and the quantitative evaluation system for this deterioration development was *** interpreting the reasons for the development of the scaling off,protective measures including chemical grouting,electro-osmosis grouting,and overlay applications were *** study also pointed out the research hotspots and shortage in the study process on the scaling *** hotspots generally focused on the development mechanism of binary structure,quantitative assessment of the degree of development,and related scientific consolidation *** shortcomings around the above directions include less attention to the development characteristics and mechanism of scaling off on earthen sites under special environment types,optimization and applicability of quantitative evaluation models,and the development and feasibility of reinforcement slurries and *** study can be beneficial in providing theoretical support for the scientific conservation and engineering practice of the scaling off on the earthen sites.

关键词： scaling off earthen sites binary structure development mechanism quantitative evaluation protection

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Mechanical Property, Oxidation and Ablation Resistance of C/C–ZrB_2–ZrC–SiC Composite Fabricated by Polymer Infiltration and Pyrolysis with Preform of C_f/ZrB_2

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Journal of Materials Science & Technology 2017年第5期33卷 481-486页

作者： dong Huang Mingyu Zhang Qizhong Huang Liping Wang Kai Tong College of Materials Science and Engineering Hunan University State Key Laboratory for Powder Metallurgy Central South University

CJC-ZrB2-ZrC-SiC composites were fabricated by polymer infiltration and pyrolysis （PIP） with a preform of G/ZrB2. The carbon fibers and the resin carbon were coated with ceramic layer after PIP in the com- posites. The composite presents a pseudo-plastic fracture due to deflection of cracks and pullout of fibers. The composite has a higher bending strength by this method in comparison with the conventional PIP process due to fewer heat treatment cycles. The static oxidation test shows that the mass loss of the composites is no more than 1% after 20 rain oxidation at 1100 ~C. The ＂core-shell＂ structure between ZrC-SiC ceramic and other phases plays a positive role in preventing the inward diffusion of oxygen. The ablation resistance of the C/C-ZrB2-ZrC-SiC composite samples was tested using a plasma generator. After ablation for 120 s, the mass and linear ablation rates of the composites are 4.65 mg cm-2 s-1 and 2.46 μm s-1, respectively. The short carbon layer shows a better ablation resistance than the nonwoven carbon fabric layer after the ceramic coating is peeled off because of its higher ceramic content.

关键词： C/C composite Ceramic-matrix composites High temperature corrosion

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Application of orthogonal design to the extraction and HPLC analysis of sedimentary pigments from lakes of the Tibetan Plateau

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Science China Earth Sciences 2016年第6期59卷 1195-1205页

作者： LIANG Jie LI dong WANG MingDa ZHANG XinYu HOU JuZhi Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau ResearchChinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education College of Chemistry and Chemical Engineering Ocean University of China Second Institute of Oceanography State Oceanic Administration Key Laboratory of Marine Ecosystem and Biogeochemistry State Oceanic Administration MOE Key Laboratory for Earth Surface Processes Peking University College of Urban and Environmental Sciences Peking University

Sedimentary pigments are useful proxy indicators of phytoplankton biomass, community structure, primary productivity and human influence in lacustrine and oceanic ecosystems. Pigments are relatively labile due to their complex chemical structures, which makes the extraction and analysis of sedimentary pigments challenging. In addition, it is important to select appropriate methods to study sedimentary pigments in regions which lack previous investigations. In this study, we adopted the L9（34） orthogonal design to develop methods of extraction and HPLC （high performance liquid chromatography） analysis of sedimentary pigments at two lakes on the Tibetan Plateau： meromictic lake-Dagze Co and dimictic lake-Jiang Co. The orthogonal design comprises 9 combinations of various parameters for extraction and HPLC analysis. The results show that the type and volume of solvent are the most important factors for pigment extraction, and the mobile phase and column selection are the most important for HPLC analysis. For the study sites, we found that the best methods to extract sedimentary pigments are as follows： the use of a mixture of acetone：methanol：water （80： 15：5, v：v：v） as the extraction solvent; sol- vent/sample ratio of 10 mL/g; sonication for 30 s and standing extraction for 6 h. The best methods for HPLC analysis are as follows： Zorbax Eclipse plus C8 column with mobile phase A, methanol：acetonitrile：0.25 M aqueous pyridine （50： 25：25, v ： v ： v） and mobile phase B, methanol： acetonitrile： acetone （20： 60： 20, v： v： v）; pH of mobile phase A adjusted to 6 with acetic acid; and HPLC column temperature maintained at 40~C. The study provides an experimental basis for future investigations of past changes in primary productivity and the response of lake ecosystems to climate change and human activities on the Tibetan Plateau.

关键词： Tibetan Plateau Sedimentary pigments Pigment extraction Pigment analysis Orthogonal design

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Comparative mammalian cell cytotoxicity of wastewater with elevated bromide and iodide after chlorination,chloramination, or ozonation

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Journal of Environmental Sciences 2017年第8期29卷 296-301页

作者： Shengkun dong Thanh H.Nguyen Michael J.Plewa Department of Civil and Environmental Enoineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA Department of Crop Sciences University of Illinois at Urbana-Champaign Urbana IL 61801 USA Safe Global Water Institute Uniuersity of Illinois at Urbana-Champaign Urbana IL 61801 USA

Recycling wastewater is becoming more common as communities around the world try to better control their water resources against an increased frequency of either prolonged droughts or intense flooding. For communities in coastal areas, wastewaters may contain elevated levels of bromide（Br^-） and iodide（I^-） from seawater intrusion or high mineral content of source waters. Disinfection of such wastewater is mandatory to prevent the spread of pathogens, however little is known about the toxicity of wastewater after disinfection in the presence of Br^-and I^-. In this study we compared the induction of chronic cytotoxicity in mammalian cells in samples of municipal secondary wastewater effluent amended with elevated levels of Br^-/I^-after disinfection by chlorine, chloramines or ozone to identify which disinfection process generated wastewater with the lowest level of adverse biological response. Chlorination increased mammalian cell cytotoxicity by 5times as compared to non-disinfected controls. Chloramination produced disinfected wastewater that expressed 6.3 times more cytotoxicity than the non-disinfected controls and was 1.3 times more cytotoxic than the chlorinated samples. Ozonation produced wastewater with cytotoxicity comparable to the non-disinfected controls and was at least 4times less cytotoxic than the chlorine disinfected wastewaters. These results indicate that compared to chlorination and chloramination, ozonation of wastewater with high Br^-/Ilevels yielded the lowest mammalian cell cytotoxicity, suggesting its potential as a more favorable method to disinfect wastewater with minimizing the biological toxicity in mind.

关键词： Cytotoxicity Ozonation Chlorination Chloramination Wastewater Bromide Iodide Disinfection

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Experimental research on electrochemical machining of titanium alloy Ti60 for a blisk

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Chinese Journal of Aeronautics 2016年第1期29卷 274-282页

作者： Chen Xuezhen Xu Zhengyang Zhu dong Fang Zhongdong Zhu Di College of Mechanical and Electrical Engineering Nanjing University of Aeronautics & Astronautics

Ti60 （Ti-5.6A1-4.8Sn2Zr-1Mo-0.35Si-0.7Nd） is a high-temperature titanium alloy that is now used for important components of aircraft engines. Electrochemical machining （ECM） is a promising technique that has several advantages, such as a high machining rate, and can be used on a wide range of difficult-to-process materials. In this paper, orthogonal experiments are conducted to investigate ECM of Ti60, with the aim of determining the influences of some electrochemical pro- cess parameters on the surface roughness. The most important parameter is found to be the frequency of the pulsed power supply. It is found that using suitably optimized parameters for ECM can greatly decrease the surface roughness ofa workpiece. A surface roughness of approximately 0.912 μm can be obtained with the following optimal parameters： NaC1 electrolyte concentration 13wt%, voltage 20 V, pulse frequency 0.4 kHz, duty cycle 0.3, temperature 23 ℃, and anode feed rate 0.5 mm/min. Furthermore, blisk blades have been successfully processed using these optimized parameters

关键词： Blisk Electrochemical machining(ECM) Surface roughness Titanium alloy Ti60

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Evaluating the accuracy performance of Lucas-Kanade algorithm in the circumstance of PIV application

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Science China(Physics,Mechanics & Astronomy) 2015年第10期58卷 60-75页

作者： PAN Chong XUE dong XU Yang WANG JinJun WEI RunJie Fluid Mechanics Key Laboratory of Ministry of Education Institute of Fluid Mechanics Beihang University Beijing Micro Vec Incorporated Company

Lucas-Kanade(LK) algorithm, usually used in optical flow filed, has recently received increasing attention from PIV community due to its advanced calculation efficiency by GPU acceleration. Although applications of this algorithm are continuously emerging,a systematic performance evaluation is still lacking. This forms the primary aim of the present work. Three warping schemes in the family of LK algorithm: forward/inverse/symmetric warping, are evaluated in a prototype flow of a hierarchy of multiple two-dimensional vortices. Second-order Newton descent is also considered here. The accuracy & efficiency of all these LK variants are investigated under a large domain of various influential parameters. It is found that the constant displacement constraint, which is a necessary building block for GPU acceleration, is the most critical issue in affecting LK algorithm's accuracy, which can be somehow ameliorated by using second-order Newton descent. Moreover, symmetric warping outbids the other two warping schemes in accuracy level, robustness to noise, convergence speed and tolerance to displacement gradient, and might be the first choice when applying LK algorithm to PIV measurement.

关键词： PIV Lucas-Kanade (LK) algorithm accuracy performance FFT-PIV algorithm

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Learning stratified 3D reconstruction

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Science China(Information Sciences) 2018年第2期61卷 224-239页

作者： Qiulei dong Mao SHU Hainan CUI Huarong XU Zhanyi HU Institute of Automation Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Computer Science and Technology Xiamen Institute of Technology

Stratified 3 D reconstruction, or a layer-by-layer 3 D reconstruction upgraded from projective to affine, then to the final metric reconstruction, is a well-known 3 D reconstruction method in computer vision. It is also a key supporting technology for various well-known applications, such as streetview, smart3 D, oblique photogrammetry. Generally speaking, the existing computer vision methods in the literature can be roughly classified into either the geometry-based approaches for spatial vision or the learning-based approaches for object vision. Although deep learning has demonstrated tremendous success in object vision in recent years,learning 3 D scene reconstruction from multiple images is still rare, even not existent, except for those on depth learning from single images. This study is to explore the feasibility of learning the stratified 3 D reconstruction from putative point correspondences across images, and to assess whether it could also be as robust to matching outliers as the traditional geometry-based methods do. In this study, a special parsimonious neural network is designed for the learning. Our results show that it is indeed possible to learn a stratified 3 D reconstruction from noisy image point correspondences, and the learnt reconstruction results appear satisfactory although they are still not on a par with the state-of-the-arts in the structurefrom-motion community due to largely its lack of an explicit robust outlier detector such as random sample consensus(RANSAC). To the best of our knowledge, our study is the first attempt in the literature to learn3 D scene reconstruction from multiple images. Our results also show that how to implicitly or explicitly integrate an outlier detector in learning methods is a key problem to solve in order to learn comparable3 D scene structures to those by the current geometry-based state-of-the-arts. Otherwise any significant advancement of learning 3 D structures from multiple images seems difficult, if not

关键词： stratified 3D reconstruction learning deep neural networks outlier detector spatial vision

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Natural product-induced oxidative stress-synergistic anti-tumor effects of chemotherapeutic agents

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Traditional Medicine Research 2024年第3期9卷 10-23页

作者： Shu-Fan Wang Shi-Qi dong Quan dong Wen-Xin Lin Mei dong Duo Liu Department of Pharmacy Harbin Medical University Cancer HospitalHarbin 150086China

Reactive oxygen species are closely related to tumor *** recent years,reactive oxygen species has become a hot spot in tumor therapy,and many natural substances in nature contain compound components with anti-tumor ***,there is a lack of discussion on the synergistic anti-tumor effects of natural products in combination with chemotherapeutic drugs through reactive oxygen *** terms“natural products”,“reactive oxygen species”,“anti-tumor”,and“chemotherapy”were used to identify the synergistic effects of natural *** conducted a systematic literature search in PubMed and Web of Science databases for relevant research articles and reviews published in recent *** systematically summarized the studies related to anti-tumor active ingredients in natural compounds in the field of reactive oxygen species in recent years.A total of 77 relevant literatures were *** them,45 literatures containing various natural products such as terpenoids,flavonoids,alkaloids,*** anti-tumor effects by regulating reactive oxygen species levels,and 32 literatures regarding adjunctive role of natural products in anti-tumor *** this study,we found that natural products exert anti-tumor effects by elevating reactive oxygen species *** provides strong theoretical support for future clinical studies.

关键词： nature products tumor reactive oxygen species combination chemotherapy oxidative stress

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Microstructure and Tribological Behavior of Self-lubricating(Si:N)-DLC/MAO Coatings on AZ80 Magnesium Substrate

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Acta Metallurgica Sinica(English Letters) 2013年第6期26卷 693-698页

作者： Wei YANG Zhennan DENG dong ZHANG Peiling KE Aiying WANG School of Materials Science and Chemical Engineering Xi an Technological University Ningbo key laboratory of Marine Protection Materials Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences Department of Prosthodontics School & Hospital of StomatologyWenzhou Medical College

The combined micro arc oxidation （MAO） and a hybrid beam deposition process was used to deposit duplex （Si：N）-DLC/MAO coatings on AZ80 magnesium alloy. The microstructure and composition of the duplex coatings were analyzed by Raman spectroscopy, X-ray photoelectron spectroscope （XPS）, scanning electron microscope （SEM） and atomic force microscopy （AFM）. Tribological behaviors of the coatings were studied by ball-on-disk friction test. It was found that the ID/IG ratio of the （Si：N）-DLC （diamond-like carbon） top films increases with decreasing C2H2/N2 ratio. The （Si：N）-DLC top film with SigN4 was formed on the MAO coated sample as the C2H2/N2 ratio was 10sccm：5sccm, which showed an increasing critical load compared with the pure DLC directly deposited on the Mg alloy substrate. As a result, the （Si：N）-DLC/MAO coating exhibited an advanced wear protection for the substrate.

关键词： Mg alloy Micro arc oxidation DLC Coating Microstructure Tribologicalbehavior

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Non-fragile switched H_∞ control for morphing aircraft with asynchronous switching

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Chinese Journal of Aeronautics 2017年第3期30卷 1127-1139页

作者： Haoyu CHENG Chaoyang dong Weilai JIANG Qing WANG Yanze HOU School of Aeronautic Science and Engineering Beihang University Beijing 100083 China College of Electrical and Information Engineering Hunan University Changsha 410082 China School of Automation Science and Electrical Engineering Beihang University Beijing 100083 China Institute of Manned Space System Engineering Beijing 100094 China

This paper deals with the problem of non-fragile linear parameter-varying（LPV） H_∞ control for morphing aircraft with asynchronous *** switched LPV model of morphing aircraft is established by Jacobian linearization approach according to the nonlinear *** data missing is taken into account in the link from sensors to controllers and the link from controllers to actuators,which satisfies Bernoulli *** non-fragile switched LPV controllers are constructed with consideration of the uncertainties of controllers and asynchronous switching *** parameter-dependent Lyapunov functional method and mode-dependent average dwell time（MDADT） method are combined to guarantee the stability and prescribed performance of the *** sufficient conditions on the solvability of the problem are derived in the form of linear matrix inequalities（LMI）.In order to achieve higher efficiency of the designing process,an algorithm is applied to divide the whole set into subsets *** results are provided to verify the effectiveness and superiority of the method in the paper.

关键词： Asynchronous switching Data missing Morphing aircraft Non-fragile H_∞ control Switched linear parameter varying system

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