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Science China Earth Sciences 2011年第2期54卷 249-258页

作者： dai lu WENG ChengYu State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China

Pollen grains deposited in marine sediments are transported from land to sea by wind or surface water *** analyzed pollen collected from the air and seawater from the coast of the Yellow Sea near China and into the western Pacific Ocean between December 2008 and January 2009 during the cruise "KX08-973".Results showed that abundant pollen grains of Artemisia and Chenopodiaceae were probably transported to the continental shelf of the East China Sea,the East Philippine Sea and the equatorial regions of the Pacific Ocean by the winter *** pollen may have even traveled over 2000 km from the East Asia continent to the tropical Pacific ***,a gradual decline of temperate components and an increase in tropical components was observed towards the tropical *** spores were rare in the air samples,but much more abundant in seawater samples,even though they were collected in nearly the same areas,which indicates that most fern spores were carried to the ocean by flowing *** results suggest that the winter monsoon may be the major pollen carrier and transporter in the study area during winter.

关键词： Western Pacific Ocean pollen and spores winter monsoon sea surface wind field HYSPLIT model

A Fast Compression Framework Based on 3D Point Cloud Data for Telepresence

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International Journal of Automation and computing 2020年第6期17卷 855-866页

作者： Zun-Ran Wang Chen-Guang Yang Shi-lu dai College of Automation Science and Engineering South China University of TechnologyGuangzhou 510640China

In this paper,a novel compression framework based on 3D point cloud data is proposed for telepresence,which consists of two *** is implemented to remove the spatial redundancy,i.e.,a robust Bayesian framework is designed to track the human motion and the 3D point cloud data of the human body is acquired by using the tracking 2D *** other part is applied to remove the temporal redundancy of the 3D point cloud *** temporal redundancy between point clouds is removed by using the motion vector,i.e.,the most similar cluster in the previous frame is found for the cluster in the current frame by comparing the cluster feature and the cluster in the current frame is replaced by the motion vector for compressing the current *** hrst,the B-SHOT(binary signatures of histograms orientation)descriptor is applied to represent the point feature for matching the corresponding point between two *** second,the K-mean algorithm is used to generate the cluster because there are a lot of unsuccessfully matched points in the current *** matching operation is exploited to find the corresponding clusters between the point cloud data of two ***,the cluster information in the current frame is replaced by the motion vector for compressing the current frame and the unsuccessfully matched clusters in the curren t and the motion vectors are transmit ted into the rem ote *** order to reduce calculation time of the B-SHOT descriptor,we introduce an octree structure into the B-SHOT *** particular,in order to improve the robustness of the matching operation,we design the cluster feature to estimate the similarity bet ween two *** tai results have shown the bet ter performance of the proposed method due to the lower calculation time and the higher compression *** proposed met hod achieves the compression ratio of 8.42 and the delay time of 1228 ms compared with the compression ratio of 5.99 and the delay time of 2163 ms in

关键词： 3D point cloud compression motion estimation signatures of histograms orientation 3D point cloud matching predicted frame and intra frame.

Modal parameter identification and damping ratio estimation from the full-scale measurements of a typical Tibetan wooden structure

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Earthquake Engineering and Engineering Vibration 2016年第4期15卷 681-695页

作者： dai lu Yang Na S.S.Law Yang Qingshan School of Civil Engineering Beijing Jiaotong University

Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structural characteristics under normal environmental loadings and their behavior under dynamic loadings. In this research, a typical Tibetan wooden wall-frame building is selected to study its dynamic characteristics. Field measurements of the structure were conducted under environmental excitation to collect acceleration responses. The stochastic subspace identification （SSI） method was adopted to calculate the structural modal parameters and obtain the out-of-plane vibration characteristics of the slab and frames. The results indicated that the wall-frame structure had a lower out-of-plane stiffness and greater in-plane stiffness due to the presence of stone walls. Due to poor identified damping ratio estimates from the SSI method, a method based on the variance upper bound was proposed to complement the existing variance lower bound method for estimating the modal damping ratio to address the significant damping variability obtained from different points and measurements. The feasibility of the proposed method was illustrated with the measured data from the floor slab of the structure. The variance lower and upper bound methods both provided consistent results compared to those from the traditional SSI method.

关键词： Tibetan wooden structure field test modal parameters damping ratio variance upper/lower bound

Surface tuning of LaCoO_(3) perovskite by acid etching to enhance its catalytic performance

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Rare Metals 2021年第3期40卷 555-562页

作者： lu dai Xin-Bo lu Guo-Hai Chu Cheng-Huan He Wang-Cheng Zhan Guo-Jun Zhou China Tobacco Zhejiang Industrial Co. LtdHangzhou 310024China Research Institute Catalysis School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

The stoichiometric LaCoO_(3) and nonstoichiometric LaCo_(1.2)O_(3) perovskite catalysts were prepared by citric acid sol-gel method,and then,LaCoO_(3) perovskite was etched with nitric *** structure,surface composition and reducibility of the catalyst were studied by X-ray diffraction(XRD),nitrogen desorption,transmission electron microscope(TEM),temperature program reduction of H_(2)(H_(2)-TPR) and X-ray photoelectron spectroscopy(XPS).It was found that nitric acid etching did not change the crystal structure and the overall morphology of the LaCoO_(3) catalyst,but it can cause the exposure of B-site Co metal to the surface of the *** a result,after acid etching,the reducibility of the LaCoO_(3) catalyst was improved,leading to the improvement in the catalytic activity of the LaCoO_(3) catalyst for CO oxidation and C_(3)H_(8) ***,the catalytic activity of the LaCoO_(3) catalyst after acid etching was higher than that of LaCo_(1.2)O_(3) and CoOx/LaCoO_(3) catalyst.

关键词： Perovskite oxide Acid etching CO oxidation Propane combustion

Magnetic interactions in a proposed diluted magnetic semiconductor(Ba_(1-x)K_x)(Zn_(1-y)Mn_y)_2P_2

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Chinese Physics B 2018年第6期27卷 369-375页

作者： Ruifeng Wang lu dai Yanci Yan Kunling Peng Xu lu Xiaoyuan Zhou Guoyu Wang Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials ＆ Micro-nano Devices Renmin University of China Beijing 100872 China

By using first-principles electronic structure calculations, we have studied the magnetic interactions in a proposed BaZn2P2-based diluted magnetic semiconductor（DMS）. For a typical compound Ba（Zn（0.944）Mn（0.056））2P2 with only spin doping, due to the superexchange interaction between Mn atoms and the lack of itinerant carriers, the short-range antiferromagnetic coupling dominates. Partially substituting K atoms for Ba atoms, which introduces itinerant hole carriers into the p orbitals of P atoms so as to link distant Mn moments with the spin-polarized hole carriers via the p–d hybridization between P and Mn atoms, is very crucial for the appearance of ferromagnetism in the compound. Furthermore, applying hydrostatic pressure first enhances and then decreases the ferromagnetic coupling in（Ba0.75 K0.25）（Zn（0.944）Mn（0.056））2P2 at a turning point around 15 GPa, which results from the combined effects of the pressure-induced variations of electron delocalization and p–d hybridization. Compared with the BaZn2 As2-based DMS, the substitution of P for As can modulate the magnetic coupling effectively. Both the results for BaZn2 P2-based and BaZn2As2-based DMSs demonstrate that the robust antiferromagnetic（AFM） coupling between the nearest Mn–Mn pairs bridged by anions is harmful to improving the performance of these Ⅱ–Ⅱ–Ⅴ based DMS materials.

关键词： magnetic semiconductor p-d hybridization magnetic coupling first-principles calculations

Microstructure characteristics and mechanical properties of Al/Mg joints manufactured by magnetic pulse welding

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Journal of Magnesium and Alloys 2023年第7期11卷 2366-2375页

作者： Congcong Zhu Shiwei Xu Wenli Gao Yifan Meng Sen Lin lu dai College of Materials Science and Engineering Hunan UniversityChangsha 410082China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China Beijing Spacecrafts Beijing 100094China

The effective connection of 1050 Al and AZ31 Mg was realized by magnetic pulse *** maximum tensile-shear force of the dissimilar Al/Mg metal lap joint reached 97%of that of the 1050 Al alloy base material by optimizing the process *** microstructure of dissimilar Al/Mg welded joints was analysed by Scanning Electron Microscope(SEM),Energy Dispersive Spectrometer(EDS)and Electron Backscattered Diffraction(EBSD).The results show that the key to obtaining high shear strength of Al/Mg dissimilar metal joints is mainly due to the following two *** the one hand,grain refinement and element interdiffusion occur at the *** the other hand,no intermetallic compounds are formed at the interface.

关键词： Al/Mg dissimilarmaterials Magneticpulsewelding Mechanicalproperties Interface EBSD

Why Greater Cash Holdings and Short-Term Debt Simultaneously Persist？ The Case of Transition Economy

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Frontiers of Business Research in China 2015年第2期9卷 207-242页

作者： lu dai Qingbin Meng Maozhu Sun School of Business Renmin University of China Beijing 100872 China

This study observes and explores a puzzle in Chinese firms whereby both cash holdings and short-term debt simultaneously account for more than 20% of total assets for at least two consecutive years over the sample period. This phenomenon conflicts with the principle of corporate value maximization, and is not clearly explained by the classical theories in corporate finance. Based on the implications in the extant literature and discussions of institutional constraints of the transition economy in China, this paper develops four hypotheses that are involved with agency conflicts between the largest shareholders and creditors and the formation of this puzzling financial structure. The empirical analyses suggest that the largest shareholders with tunneling motives seek to hold more cash to serve their private interests and/or the consequent operational deficit of the listed corporations. To the ends, these corporations tend to manage the timing of short term debt financing to increase cash reserves temporarily at the end of year. Essentially, greater cash holdings on the balance sheet of these corporations related with the puzzle become a misleading signal for potential creditors, possibly contributing to the refinancing of short-term debt of these listed firms for the following year. Hence, the puzzling financial structure is connected with the timing of debt financing and adverse selection of creditors. This study enriches the stream of literature on cash holdings and debt maturity, and provides new evidence on the impact of agency problems of the largest shareholders on the association between cash holdings and debt maturity in the context of a transition economy.

关键词： cash holdings short-term debt agency conflicts tunneling largestshareholders puzzle financial policy

Lipids, lipid metabolism and Kaposi's sarcoma-associated herpesvirus pathogenesis

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Virologica Sinica 2017年第5期32卷 369-375页

作者： lu dai Zhen Lin Wei Jiang Erik K.Flemington Zhiqiang Qin Department of Genetics Louisiana State University Health Sciences Center Louisiana Cancer Research Center New Orleans 70112 USA Department of Pediatrics East Hospital Tongji University School of Medicine Shanghai 200120 China Research Center for Translational Medicine and Key Laboratory of Arrhythmias East Hospital TongjiUniversity School of Medicine Shanghai 200120 China Department of Pathology Tulane University Health Sciences Center Tulane Cancer CenterNew Orleans 70112 USA Department of Microbiology and Immunology Division of Infectious Diseases Department of MedicineMedical University of South Carolina Charleston 29425 USA

Lipids are essential for mammalian cells to maintain many physiological functions. Emerging evidence has shown that cancer cells can develop specific alterations in lipid biosynthesis and metabolism to facilitate their survival and various malignant behaviors. To date, the precise role of cellular lipids and lipid metabolism in viral oncogenesis is still largely unclear with only a handful of literature covering this topic to implicate lipid metabolism in oncogenic virus associated pathogenesis. In this review, we focus on the role of lipid biosynthesis and metabolism in the pathogenesis of the Kaposi's sarcoma-associated herpesvirus, a common causative factor for cancers arising in the immunocompromised settings.

关键词： Kaposi’s sarcoma-associated herpesvirus(KSHV) herpesvirus lipid metabolism

Leader-Follower Formation Control of Fully Actuated USVs With Prescribed Performance and Collision Avoidance 36

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Leader-Follower Formation Control of Fully Actuated USVs Wit...

Study on growing correlation length prior to the earthquakes occurred in Gansu Province and its nearby area

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作者： Shi-lu dai Shude He Fei luo Ning Wang School of Automation Science and Engineering South China University of Technology Centre for Robotics and Neural Systems Plymouth University

ISBN: (纸本)9781538629185

This paper addresses robust leader-follower formation control problem with prescribed performance and collision avoidance for a group of fully actuated unmanned surface vehicles（USVs）.The dynamic surface control（DSC） technique is employed to introduce a first-order low-pass filter in the kinematic design such that the utilization on the leader vehicle’s acceleration is avoided in the kinetics control *** modelling uncertainties and external disturbances are discussed,in which they are lumped together and an observation mechanism is presented to estimate the total ***,disturbance-observer-based formation controller is designed using backstepping procedure,error transformation,and Lyapunov *** proposed formation controller ensures uniformly ultimate boundedness of all closed-loop signals with guaranteeing prescribed performance of formation errors and avoids the collision between the follower and its *** results demonstrates the effectiveness of the proposed controller.

关键词： Formation control prescribed performance collision avoidance unmanned surface vehicles(USVs) disturbances

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Acta Seismologica Sinica(English Edition) 2004年第5期17卷 564-570页

作者： RONG dai-lu(荣代潞) LI Ya-rong(李亚荣) LIU Xu-zhou(刘旭宙) Lanzhou Base of Center for analysis and Prediction China Earthquake AdministrationLanzhou730000China Lanzhou Base of Center for analysis and PredictionChina Earthquake AdministrationLanzhou730000China Lanzhou Base of Center for analysis and PredictionChina Earthquake AdministrationLanzhou730000China

The growing correlation length prior to the moderate-great earthquakes occurred in Gansu Province and its nearby area since 1986 has been studied using the method of single-link cluster analysis (SLC). According to different conditions in the source area, the circular spatial window centered in the epicenter and the parallelgrammic spatial window along the fault belt have been selected. The results show that the phenomena of growing correlation length have been observed before the earthquakes studied in the paper.

关键词： moderate-great earthquake correlation length single-link cluster analysis Gansu