检索结果-南通市图书馆

A Routing Protocol for Urban Vehicular Multi-hop Data Delivery

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2016年第2期25卷 348-356页

作者： CHANG Sang-woo LEE Sang-sun Department of Electronic Engineering Hanyang University

Vehicular ad-hoc network(VANET) has distinctive environments such as highly dynamic topology, frequently disconnected network, hard delay constraints for safety-related application, and various communications environments based on highway or urban traffic scenarios. Therefore, development of a suitable routing protocol that considers these characteristics of VANET should be needed. In this paper we propose the improved distance-based VANET routing protocol in urban traffic environments. We apply approaches to multi-hop broadcast scheme for reliable packet dissemination in the intersection and stable route decision scheme based on the adaptive waiting time. The performance is evaluated under simulation which is implemented with the Manhattan urban traffic model. The results show the improved performance as compared with other protocols.

关键词： Distance-based routing protocol Vehicle-to-vehicle communication Waiting time Urban traffic environments Vehicular ad-hoc network(VANET)

Ce改性Fe_2O_3/γ-Al_2O_3催化剂的表征及催化活性研究

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

功能材料 2006年第6期37卷 915-918页

作者：刘琰孙德智哈尔滨工业大学市政环境工程学院黑龙江哈尔滨150090

采用浸渍焙烧法分别制备了Fe2O3/γ-Al2O3和Ce改性的Fe2O3/-γAl2O3催化剂,采用BET、XRD、XPS和XRF对其结构进行了表征,并用于常温常压CWPO工艺中,考察了Ce的掺杂对Fe2O3/-γAl2O3催化剂催化活性和稳定性的影响。结果表明,Ce的掺杂提高... 详细信息

采用浸渍焙烧法分别制备了Fe2O3/γ-Al2O3和Ce改性的Fe2O3/-γAl2O3催化剂,采用BET、XRD、XPS和XRF对其结构进行了表征,并用于常温常压CWPO工艺中,考察了Ce的掺杂对Fe2O3/-γAl2O3催化剂催化活性和稳定性的影响。结果表明,Ce的掺杂提高了活性组分在载体表面的分散度,在相同的CWPO工艺条件下,Ce的掺杂使得Fe2O3/-γAl2O3催化剂处理偶氮染料废水的催化活性提高了10%左右。

关键词：催化湿式过氧化氢氧化工艺常温常压催化剂偶氮染料废水处理

Estimation of carbon dioxide flux and source partitioning over Beijing, China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第12期25卷 2429-2434页

作者： Tao Song Yuesi Wang Yang sun State key laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences

The magnitude and partitioning of carbon dioxide emission from the urban area in Beijing, China was estimated based on a statistical approach. Results showed that the urban surface is a net source of CO2 to atmosphere. The main sources of CO2 are vehicles, which accounted for 75.5% and 38.9% of CO2 emission in summer and winter, respectively. At midday in summer, the CO2 uptake of-0.034 mg/（m^***） indicated that vegetation is an important sink of CO2 in summer. Comparison between the annual emission rates of CO2 from the statistical approach and that directly measured by the eddy covariance technique implies that a bottom-up emission approach is a viable means to estimate CO2 emission in an urban area.

关键词： C02 emission source eddy covariance

Structural eigenvalue analysis under the constraint of a fuzzy convex set model

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2018年第4期34卷 653-666页

作者： Wencai sun Zichun Yang Guobing Chen College of Power Engineering Naval University of Engineering

In small-sample problems, determining and controlling the errors of ordinary rigid convex set models are difficult. Therefore, a new uncertainty model called the fuzzy convex set（FCS） model is built and investigated in detail. An approach was developed to analyze the fuzzy properties of the structural eigenvalues with FCS constraints. Through this method, the approximate possibility distribution of the structural eigenvalue can be obtained. Furthermore, based on the symmetric F-programming theory, the conditional maximum and minimum values for the structural eigenvalue are presented, which can serve as nonfuzzy quantitative indicators for fuzzy problems. A practical application is provided to demonstrate the practicability and effectiveness of the proposed methods.

关键词： Structural eigenvalue Fuzzy Convex set Conditional extreme Symmetric F-programming

Blind detection of liquefaction by existing methods for New Zealand M_L6.3 earthquake on Feb. 22,2011

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2011年第4期10卷 465-474页

作者： sun Rui Tang Fuhui Chen Longwei Institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China

Real-time liquefaction monitoring and warning techniques are new ways to mitigate liquefaction hazard. A key point is to establish a reverse liquefaction detection method based on seismic records. However, the existing methods are quite limited and the reliability requires verification. On Feb. 22, 2011 an earthquake of magnitude 6.3 struck at New Zealand＇s South Island. Remarkable liquefaction phenomena were reported, which provide an opportunity to verify the existing liquefaction detection methods. 27 acceleration records within 50 km to the epicenter were selected to perform a blind detection by using the existing methods, including Miyajima method, Suzuki method, Kostadinov-Yamazaki method and Yuan-sun method. The blind detection results indicate that Yuan-sun method gives correct results for seven confirmed sites, and Suzuki method and Yuan-sun method yield correct detection for a reported non-liquefied site. Four methods including the Yuan-sun method give identical detection for four sites and three methods also including the Yuan-sun method give identical detection for ten sites. Besides, there are five sites, for which the four methods give opposite detection.

关键词： New Zealand earthquake liquefaction detection methods blind detection

Leveraged fault identification method for receiver autonomous integrity monitoring

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2015年第4期28卷 1217-1225页

作者： sun Yuan Zhang Jun Xue Rui School of Electronic and Information Engineering Beihang University

Receiver autonomous integrity monitoring（RAIM） provides integrity monitoring of global positioning system（GPS） for safety-of-life *** the process of RAIM, fault identification（FI） enables navigation to continue in the presence of fault *** by satellite geometry, the leverage of each measurement in position solution may differ ***, the conventional RAIM FI methods are generally based on maximum likelihood of ranging error for different measurements, thereby causing a major decrease in the probability of correct identification for the fault measurement with high *** this paper, the impact of leverage on the fault identification is *** leveraged RAIM fault identification（L-RAIM FI） method is proposed with consideration of the difference in leverage for each satellite in ***,the theoretical probability of correct identification is derived to evaluate the performance of L-RAIM FI *** experiments in various typical scenarios demonstrate the effectiveness of L-RAIM FI method over conventional FI methods in the probability of correct identification for the fault with high leverage.

关键词： Fault identification Global positioning system Leverage Navigation systems Receiver autonomousintegrity monitoring

AEROELASTIC PROPERTIES OF SANDWICH BEAM WITH PYRAMIDAL LATTICE CORE CONSIDERING GEOMETRIC NONLINEARITY IN THE SUPERSONIC AIRFLOW

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2015年第6期28卷 639-646页

作者： Fengming Li zhiguang Song Chunchun sun College of Mechanical Engineering Beijing University of Technology P.O. Box 137 School of AstronauticsHarbin Institute of Technology Hong Du Aviation Industry Group

The equation of motion of sandwich beam with pyramidal lattice core in the supersonic flow considering geometric nonlinearity is formulated using Hamilton＇s principle. The piston theory is used to evaluate aerodynamic pressure. The structural aeroelastic properties are analyzed using frequency- and time-domain methods, and some interesting phenomena are observed. It is noted that the flutter of sandwich beam occurs under the coupling effect of low order modes. The critical flutter aerodynamic pressure of the sandwich beam is higher than that of the isotropic beam with the same weight, length and width. The influence of inclination angle of core truss on flutter characteristic is analyzed.

关键词： sandwich beam pyramidal lattice core geometric nonlinearity aeroelastic flutter supersonic flow

Integrated lifting line/surface panel method for optimal propeller design with consideration of hub effect

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2019年第6期31卷 1218-1230页

作者： Wen-yu sun Guo-fu Huang China Ship Scientific Research Center Wuxi 214082China

An optimal marine propeller design method is proposed,which integrates the lifting line and surface panel method and is characterized by the use of the surface panel method to take the hub effect into *** developing an integrated approach instead of an iterative method for the calculation of the interaction between the hub and the designed blades,the hub effects on the optimal circulation can be accounted for throughout the theoretical design *** new integrated method provides a fast and accurate enough method to model the straight forward hub surface,in the optimal propeller design.A systematic design procedure from the basic design inputs to the blade geometry determination is performed and the designed propellers are validated by the surface panel method and the RANS *** design and analysis cases are considered by different approaches with comparison and *** a comparative study including different hub geometries is also performed to reveal the mechanism of the hub effect on the distributions of the propeller optimal loads.

关键词： Optimal circulation design lifting line method surface panel method hub effect

Efficient photocatalytic overall water splitting achieved with polymeric semiconductor-based Z-scheme heterostructures

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

Science China Chemistry 2021年第6期64卷 875-876页

作者： Xupeng Zong Wenshuai Jiang Zaicheng sun Center of Excellence for Environmental Safety and Biological Effects Beijing Key Laboratory for Green Catalysis and SeparationDepartment of Chemistry and BiologyBeijing University of TechnologyBeijing 100124China

Developing new technology to utilize solar power as alternative energy is imperative to meet the challenge of fossil fuel consumption and consequently environmental *** overall water splitting is regarded as an ideal reaction for realizing solar-to-chemical energy *** to date,many particle-suspension systems have been studied on a laboratory-scale with inorganic semiconductors including metal oxides,(oxy)nitrides.

关键词： splitting utilize polymeric