检索结果-南通市图书馆

Comparison of copper speciation in the Zhujiang River Estuary between summer and winter: implication for upwelling current

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2005年第4期24卷 72-80页

作者： long Aimin CHEN Shaoyong YAN Wen tian Zhenlong South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China

The contents of total copper, total dissolved copper, particulate copper, and free ion copper in the Zhujiang River Estuary were investigated in July 2002 and January 2003 respectively, and the spatial distribution trend of these species of copper were compared in two cruises. It was found that, in summer, the total copper content in the Zhujiang River Estuary increased with salinity, while the content office ion copper decreased with salinity. However, in winter, the contents of total copper and free ion copper both decreased with salinity. So, it could be concluded that, copper content and speciation in the Zhujiang River Estuary were regulated by other factors than runoffdiffusion such as upwelling current. In order to prove the spatial trend of rice ion copper content in the Zhujiang River Estuary, the cultivation of Dunaliella tertiolecta in waters obtained from sampling stations with different salinities was carried out, and the copper uptake by algae cells was measured then. It was found that, the cells＇ uptake of copper increased with rice ion copper, not the content of total copper.

关键词： speciation copper Zhujiang River Estuary

Some Properties for the Largest Component of Random Geometric Graphs with Applications in Sensor Networks

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2009年第4期25卷 579-592页

作者： Ge Chen tian-de Guo Chang-long Yao School of Mathematical Science Graduate University of Chinese Academy of Sciences Beijing 100049 China

In this paper we consider the standard Poisson Boolean model of random geometric graphs G（Hλ,s; 1） in Rd and study the properties of the order of the largest component L1 （G（Hλ,s; 1）） . We prove that ElL1 （G（Hλ,s; 1））] is smooth with respect to A, and is derivable with respect to s. Also, we give the expression of these derivatives. These studies provide some new methods for the theory of the largest component of finite random geometric graphs （not asymptotic graphs as s - co） in the high dimensional space （d 〉 2）. Moreover, we investigate the convergence rate of E[L1（G（Hλ,s; 1））]. These results have significance for theory development of random geometric graphs and its practical application. Using our theories, we construct and solve a new optimal energy-efficient topology control model of wireless sensor networks, which has the significance of theoretical foundation and guidance for the design of network layout.

关键词： Random geometric graph the largest component wireless sensor networks topology control

A class of transient acceleration models consistent with Big Bang cosmology

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2014年第2期14卷 129-138页

作者： tian-long Zu Jie-Wen Chen Yang Zhang Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of China

Is it possible that the current cosmic accelerating expansion will turn into a decelerating one？ Can this transition be realized by some viable theoretical model that is consistent with the standard Big Bang cosmology？ We study a class of phenomeno- logical models with a transient acceleration, based on a dynamical dark energy with a very general form of equation of state Pde = αPde -- βpdem. It mimics the cosmolog- ical constant αde → const for a small scale factor a, and behaves as a barotropic gas with pde → α-3（α＋1） with α 〉 0 for large a. The cosmic evolution of four models in the class has been examined in detail, and all yield a smooth transient acceleration. Depending on the specific model, the future universe may be dominated by either dark energy or by matter. In two models, the dynamical dark energy can be explicitly real- ized by a scalar field with an analytical potential V（O）. Moreover, a statistical analysis shows that the models can be as robust as ACDM in confronting the observational data of Type Ia supernovae, cosmic microwave background （CMB） and baryon acoustic os- cillation. As improvements over previous studies, our models overcome the problem of over-abundance of dark energy during early eras, and satisfy the constraints on dark energy from WMAP observations of CMB.

关键词： cosmology: theory -- methods: analytical

Novel technology of electroless Ni-W-P on plastics and its interface behavior

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第Z1期14卷 136-139页

作者： WANG tian-xu HU Yong-jun MENG Ji-long College of Mechanical Engineering South China University of TechnologyGuangzhou 510641 China College of Mechanical Engineering South China University of TechnologyGuangzhou 510641 China College of Mechanical Engineering South China University of TechnologyGuangzhou 510641 China

The electroless Ni-W-P coatings on polyoxymethylene(POM) were prepared. The POM was pretreated by hot spraying Al powder on it. Before the electroless Ni-W-P deposition, the POM with Al coating was flash plated in alkaline bath. The mechanism of Ni-W-P deposition was studied and the technology was optimized. The XRD analysis shows that the "as-deposited" Ni-W-P plating has mixed crystalline structure. The hardness value of deposits is more than HV700. The abrasion resistance of deposits is six times more than that of POM. Bending test was used to determine the cohesion between the deposits and the substrates. SEM was used to study the behavior of surface abrasion and interface bonding condition. The reason for the excellent cohesion was interpreted.

关键词： plastics electroless plating interface Ni alloy

Fuzzy Chaos Control for Vehicle Lateral Dynamics Based on Active Suspension System

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第4期27卷 793-801页

作者： HUANG Chen CHEN long JIANG Haobin YUAN Chaochun XIA tian School of Automobile and Traffic Engineering Jiangsu University

The existing research of the active suspension system（ASS） mainly focuses on the different evaluation indexes and control strategies. Among the different components, the nonlinear characteristics of practical systems and control are usually not considered for vehicle lateral dynamics. But the vehicle model has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, the nonlinear dynamic model of lateral system is considered and also the adaptive neural network of tire is introduced. By nonlinear analysis methods, such as the bifurcation diagram and Lyapunov exponent, it has shown that the lateral dynamics exhibits complicated motions with the forward speed. Then, a fuzzy control method is applied to the lateral system aiming to convert chaos into periodic motion using the linear-state feedback of an available lateral force with changing tire load. Finally, the rapid control prototyping is built to conduct the real vehicle test. By comparison of time response diagram, phase portraits and Lyapunov exponents at different work conditions, the results on step input and S-shaped road indicate that the slip angle and yaw velocity of lateral dynamics enter into stable domain and the results of test are consistent to the simulation and verified the correctness of simulation. And the Lyapunov exponents of the closed-loop system are becoming from positive to negative. This research proposes a fuzzy control method which has sufficient suppress chaotic motions as an effective active suspension system.

关键词： chaos control fuzzy active suspension system vehicle lateral dynamics

RGB Image‑ and Lidar‑Based 3D Object Detection Under Multiple Lighting Scenarios

在线全文

学校读者我要写书评

暂无评论

Automotive Innovation 2022年第3期5卷 251-259页

作者： Wentao Chen Wei tian xiang Xie Wilhelm Stork School of Automotive Studies Tongji UniversityShanghaiChina Karlsruhe Institute of Technology 76131 KarlsruheGermany

In recent years,camera-and lidar-based 3D object detection has achieved great ***,the related researches mainly focus on normal illumination conditions;the performance of their 3D detection algorithms will decrease under low lighting scenarios such as in the *** work attempts to improve the fusion strategies on 3D vehicle detection accuracy in multiple lighting ***,distance and uncertainty information is incorporated to guide the“painting”of semantic information onto point cloud during the data ***,a multitask framework is designed,which incorpo-rates uncertainty learning to improve detection accuracy under low-illumination *** the validation on KITTI and Dark-KITTI benchmark,the proposed method increases the vehicle detection accuracy on the KITTI benchmark by 1.35%and the generality of the model is validated on the proposed Dark-KITTI dataset,with a gain of 0.64%for vehicle detection.

关键词： 3D object detection Multi-sensor fusion Uncertainty estimation Semantic segmentation PointPainting

Evolution of Artificial Base Pairs with Hydrogen Bond Complementarity

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2020年第2期36卷 151-156页

作者： tian Jimniao CHEN Sikai WANG xiang LI Juan Institute of Molecular Medicine State Key laboratory of Oncogenes and Related GenesRenji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200127P.R.China Key Laboratory for Analytical Science of Food Safety and Biology Ministry of EducationFujian Provincial Key Laboratory of Analysis and Detection Technology for Food SafetyState Key Laboratory of Photocatalysis on Energy and EnvironmentCollege of ChemistryFuzhou UniversityFuzhou 350108.P.R.China

Artificial base pairs,from the perspective of synthetic biology,are designed to contain the features of modularity,orthogonality,and *** the development of artificial base pairs has beat endowed with responsibility to understand the biological process,improve the recognition capacity and stability of aptamers,and develop the nucleoside drugs,diagnosis,and drag *** this review,we first gave a concise introduction of artificial base pairs based on their interaction modes including alternative hydrogen bonding,hydrophobic interaction,and metal *** we displayed the detailed information of artificial base pairs with hydrogen bonding interaction,and analyzed how the changes of their structures affect their ***,we highlighted the applications of functional artificial base pairs in aptamer discovery,diagnosis,and drug ***,an insight into the remaining challenges and future perspective of the artificial bases was provided.

关键词： Artificial base pair Nucleic add Hydrogen bonding base pair Hydrophobic base pair Metal-base pair Aptamcr

Response of a transmission tower-line system at a canyon site to spatially varying ground motions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第2期12卷 103-120页

作者： Hong-nan LI Feng-long BAI Li tian Hong HAO State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China Sehool of Civil and Resource Engineering University of Western Australia WA 6009 Australia

Collapses of transmission towers were often observed in previous large earthquakes such as the Chi-Chi earthquake in Taiwan and Wenchuan earthquake in Sichuan,China. These collapses were partially caused by the pulling forces from the transmission lines generated from out-of-phase responses of the adjacent towers owing to spatially varying earthquake ground motions. In this paper,a 3D finite element model of the transmission tower-line system is established considering the geometric nonlinearity of transmission lines. The nonlinear responses of the structural system at a canyon site are analyzed subjected to spatially varying ground motions. The spatial variations of ground motion associated with the wave passage,coherency loss,and local site effects are given. The spatially varying ground motions are simulated stochastically based on an empirical coherency loss function and a filtered Tajimi-Kanai power spectral density function. The site effect is considered by a transfer function derived from 1D wave propagation theory. Compared with structural responses calculated using the uniform ground motion and delayed excitations,numerical results indicate that seismic responses of transmission towers and power lines are amplified when considering spatially varying ground motions including site effects. Each factor of ground motion spatial variations has a significant effect on the seismic response of the structure,especially for the local site effect. Therefore,neglecting the earthquake ground motion spatial variations may lead to a substantial underestimation of the response of transmission tower-line system during strong earthquakes. Each effect of ground motion spatial variations should be incorporated in seismic analysis of the structural system.

关键词： Transmission tower-line system Canyon site Spatially varying ground motions Coherency loss Local site effect

Metal-ligand coordinated Ca(DS)_2/C_(14)DMAO/H_2O system:Phase behavior and rheological property

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2011年第3期54卷 490-496页

作者： LI xiang tian HongShan DING Qi SONG AiXin Department of Chemistry and Chemical Engineering Henan University of Urban Construction Pingdingshan 467000 China Key Laboratory of Colloid and Interface Chemistry (Shandong University) Ministry of Education Jinan 250100 China

A metal-ligand coordinated surfactant system formed by calcium dodecylsulfate(Ca(DS)2)/tetradecyldimethylamine oxide (C14DMAO)/H2O was studied in terms of surface tension,conductivity,negative-staining TEM,phase behavior and rheological *** C14DMAO solution,when Ca(DS)2 is added,metal-ligand complexes form between the Ca 2+and N→O group of *** this metal-ligand driving force,different phases can be obtained at different concentrations and different ratios of Ca(DS)2 and *** the fixed C14DMAO concentration,L1-phase consisting of spherical micelles forms at *** the addition of Ca(DS)2,the spherical micelles elongate to be wormlike micelles and then after an L1/L-two phase region,the birefringent vesicle-phase(Lv-phase)region is *** Ca(DS)2 concentration continues to increase,a gel-phase region is found after the Lv-phase region and then precipitates of undissolved Ca(DS)2 *** transition between different phases is affected by temperature *** wormlike micellar solutions and vesicle solutions were checked by rheological measurements and showed apparent viscoelasticity at high surfactant concentrations.

关键词： metal-ligand phase behavior Lvphase wormlike micellar phase rheological property