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2003-2017 全部
为您找到包含“National Natural Science Foundation of China”的内容共1292

Lu Yinfeng,Zhang Xiaohong

As a generalization of BCI-algebras with condition (S) and pseudo-BCK algebras with condition (pP), the notion of pseudo-BCI algebras with condition (pP) is introduced. An example of pseudo-BCI algebras with condition (pP) is given, the result that every anti-grouped pseudo-BCI algebras is with condition (pP) is proved. Some properties of pseudo-BCI algebras with condition (pP) are investigated and the branch properties of pseudo-BCI algebras with condition (pP) are discussed.

2010-10-09

Ningbo National Natural Science Foundation of China(Grant No. 2009A610078

National Natural Science Foundation of China (Grant No. 60775038

Faculty of Sciences, Ningbo University,Faculty of Sciences, Ningbo University

#Mathematics#

0评论(0 分享(0)

LI Lei,YU Jia

In recent years, the multi-document summary technology has gotten more and more attention in the field of natural language processing. However, the relationship between the topics and the level information are rarely considered, and sentence scoring is also a very important and difficult task in the multi-document summary process. The results of hLDA (hierarchical Latent Dirichlet Allocation) in the hierarchical topic modeling have been widely validated. Therefore this paper focused on the nodes in the hLDA model, researched the hLDA and semantic based sentence scoring method and presented seven algorithms to provide a strong basis for the multi-document summary.

2013-10-29

National Natural Science Foundation of China (No.61202247

National Natural Science Foundation of China (No.71231002

School of Computer Science, Beijing University of Posts and Telecommunications, 100876,School of Computer Science, Beijing University of Posts and Telecommunications, 100876

#Computer Science and Technology#

0评论(0 分享(0)

Yu Xiangqing ,Bian Hai ,Ge Qin ,Wang Wenxiu ,Yang Zhen ,Zhang Limin ,Liu Zhengmin

The study on hydrogen absorption and desorption properties of titanium under an initial hydrogen pressure of 0.25 MPa at different temperature was fulfilled, the hydrogen absorption rate constant k value is 7.364×10-3s-1 under an initial hydrogen pressure of 0.25 MPa at 773 K. The depth profile of hydrogen in titanium was performed by secondary ion mass spectroscopy, the relative hydrogen content is invariable between about 700nm and 1250nm in titanium. The X-ray diffraction and scanning electron microscope studies on titanium hydride were performed, the TiH phase was found after hydrogen desorption of titanium at 773 K after heating for 5400 seconds.

2008-11-18

the National Natural Science Foundation of China( 10605011

School of Nuclear Science and Technology,Lanzhou University,School of Nuclear Science and Technology,Lanzhou University,School of Nuclear Science and Technology,Lanzhou University,School of Nuclear Science and Technology,Lanzhou University,School of Nuclear Science and Technology,Lanzhou University,School of Nuclear Science and Technology,Lanzhou University,School of Nuclear Science and Technology,Lanzhou University

#Nuclear Science and Technology#

0评论(0 分享(0)

Wen Zhicheng,Fu Mingfu,Chen Liangsen

In the present paper, the Lagrangian finite plasticity theory is discussed based on the theory of materials with elastic range by the assumptions of the existence of a yield functional and a flow rule, to generalize the framework of A.E. Green, P.M. Naghdi and J. Casey (see Naghdi(1990), Brown et al (2003)), so that it can describe better the mechanical behaviors of anisotropic elastic-plastic materials and the strain induced anisotropy. Here the plastic strain, also called intermediate strain, is defined by the plastic stress, and the elastic response functional is assumed to be a functional of plastic strain history. As a result of this definition of intermediate strain, the elastic response functional has a special form, the normal flow rule of generally accepted Il’yushin’s Postulate is the evolution law for the plastic stress. If the plastic stress is also defined to describe the kinematical hardening, it is the kinematical hardening law. The definitions of strain, plastic strain and elastic strain are discussed from a geometric point of view. It is shown that Green-Naghdi elastic strain is the Lagrange elastic strain. The discussion of the consequences of Il’yushin’s Postulate has detailed, the necessary and sufficient condition is obtained. The rate-form of this theory is obtained. The material symmetry and strain induced anisotropy are also discussed in detail. Finally an example of isotropic elastic plastic materials is given. It has been shown that in general this model can satisfy the basic conditions such as Il’yushin postulate and uniqueness and existence of solution of flow rule for any plastic deformation.

2009-01-08

National Natural Science Foundation of China(10272055

University of Kentucky,School of Architectural Engineering, Nanchang University,School of Architectural Engineering, Nanchang University

#Mechanics#

0评论(0 分享(0)

sun chen

Orthogonal Frequency Division Multiple Access (OFDMA) has already been the main multiple access technology for 3G long term evolution(LTE) and 4G.This paper analyzes characteristics of OFDMA multiple access technology and puts forward a new OFDMA handover algorithm (sub-carriers bidirectional arrayed handover algorithm, SBA). The simulation results show that, during handover process, SBA algorithm proposed in this paper guarantees users in OFDMA system keeping the best channel SIR and QoS. Moreover, SBA algorithm decreases the extra consumption of the handover, and improves OFDMA system performance.

2009-02-09

he National Natural Science Foundation of China (60672131

beijing university of posts and telecommunications,Information & Electronics Technology Lab

#Electrics, Communication and Autocontrol Technology#

0评论(0 分享(0)

WEI Shaowen,LIU Yuxiao

Using the new physical interpretation of quasinormal modes proposed by Maggiore, we calculate the area and entropy spectra for the 3-dimensional and 5-dimensional large Ads black hole. The spectra are obtained by imposing the Bohr-Sommerfeld quantization condition and the adiabatic invariant quantity. With this semiclassical method, we find that the spacings of the area and entropy spectra aare equidistant and independent of the Ads radius of the black hole for both the casess. However, the spacings of the spectra are not the same for different dimension of space-time. The equidistant area spectra will be broken when the black hole has other paprameters (i.e., charge and angular momentum) of in a non-Einstein's gravity theory.

2010-11-18

the National Natural Science Foundation of China (No. 10705013)

Institute of Theoretical Physics, Lanzhou University,Institute of Theoretical Physics, Lanzhou University

#Physics#

0评论(0 分享(0)

ZHENG Lei,ZHANG Maicang,DONG Jianxin

Hot corrosion performances of powder metallurgy (PM) René88DT Ni-based superalloy in molten 25%NaCl+75%Na2SO4 salts at 650℃, 700℃ and 750℃ were investigated by weight loss measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Experimental results showed that PM René88DT superalloy follows a parabolic law of corrosion kinetics at 650℃, but first parabolic and then linear ones at 700℃ and 750 ℃. The changes of kinetics at 700℃ and 750℃ were concluded to be caused by severe spalling of corrosion layers. Corrosion layers on the surface of PM René88DT superalloy were detected to be composed of Cr2O3, NiO, and Ni3S2 at each temperature. Cross-sectional morphologies and corresponding elemental maps indicated that corrosion layers are composed of oxides and sulfides at all temperatures. According to these results, a cooperating mechanism of oxidation and sulfuration for hot corrosion of PM René88DT Ni-based superalloy was confirmed.

2010-12-27

National Natural Science Foundation of China (No. 50771011 and No. 51001011)

School of Materials Science and Engineering, University of Science and Technology Beijing,School of Materials Science and Engineering, University of Science and Technology Beijing,School of Materials Science and Engineering, University of Science and Technology Beijing

#Materials Science#

0评论(0 分享(0)

Xia Siqing,Yan Ning,Zhu Jun,Zhang Yongming

The extensive use of phenol compounds and the inability to remove these compounds during wastewater treatment have resulted in the widespread occurrence of phenols in the natural environment. Phenols have been linked to serious risks to human and environmental health. Hence the need to develop methods for the removal of phenols from wastewater and source waters is a pressing challenge for our time. In this study, light ceramic particles were immersed in activated sludge acclimated to degrade phenol, and microorganisms were allowed to attach to the particles surface to form biofilm, then the ceramic particles with biofilm were moved into the photolytic circulating-bed biofilm reactor (PCBBR) made of quartz glass, which was used for degradation of phenol by three protocols: photolysis with UV light alone (P), biodegradation alone (B), and the two mechanisms operating simultaneously (photobiodegradation, P&B). The experimental results indicated that phenol removal rate was quickest by B experiment. However, P&B experiment gave more complete mineralization of phenol than that by other protocols. During P&B experiment, the microorganisms grown on porous ceramic carrier still kept the bioactivity degrading phenol, even under UV light irradiation. But the dominant members of the bacterial community changed dramatically after the intimately coupled photo-biodegradation, according to molecular biological analysis to the biofilm. Whereas Beijerinckia sp. was the dominant strain in the inoculum, it was replaced by Thauera sp. MZ1T that played a main role on degrading phenol during P&B experiment.

2010-12-28

National Natural Science Foundation of China (50978164 and 50678102) and the Special Foundation of Chinese Colleges and Universities Doctoral Discipline

College of Environmental Science and Engineering, Tongji University, College of Environmental Science and Engineering, Tongji University,Department of Environmental Engineering, Shanghai Normal University,Department of Environmental Engineering, Shanghai Normal University

#Environmental Science and Techology#

0评论(0 分享(0)

JIN Jing,CAO Shoufan,LIU Hongtao,GAO Jiping,WANG Luping

Filling modification is an important method to improve the performance of UHMWPE. In this article, the basalt fibers were used to fill the UHMWPE because of their outstanding tribological performance. Firstly, in order to maintain the UHMWPE's excellent impact toughness, the UHMWPE composites with the filler content of 5 wt.%-20 wt.% were prepared. Then the impact toughness and tribological performances of the composites were tested. Also the wear mechanism was analyzed. The results indicated that the UHMWPE composites' impact toughness was decreased when filled with the basalt fibers. Under the same experimental conditions, the friction coefficient of the UHMWPE composites filled with basalt fibers was decreased to some extent, and the wear loss of the composites was significantly reduced. The analysis showed that the wear type of the UHMWPE composites was changed when filled with the basalt fibers. So the wear-resistant performance of the UHMWPE composites was effectively enhanced.

2010-12-28

National Natural Science Foundation of China (Grant No. 51075387

School of Materials Science and Engineering, China University of Mining & Technology,School of Materials Science and Engineering, China University of Mining & Technology,School of Materials Science and Engineering, China University of Mining & Technology,School of Materials Science and Engineering, China University of Mining & Technology,School of Materials Science and Engineering, China University of Mining & Technology

#Materials Science#

0评论(0 分享(0)

JIN Jing,CAO Shoufan,LIU Hongtao,GAO Jiping,WANG Luping

Filling modification is an important method to improve the performance of UHMWPE. In this article, the basalt fibers were used to fill the UHMWPE because of their outstanding mechanical performance. In order to maintain the UHMWPE's excellent impact toughness, the UHMWPE composites with the filler content of 5 wt.%-20 wt.% were prepared. Then some of the mechanical performances of the composites were tested. The results indicated that the impact strength of UHMWPE composites was significantly decreased as the weight percentage of the basalt fibers was increased. The strength, hardness and creep resistance of the UHMWPE composites were all increased in a large degree with the increase of the content of basalt fibers. So, with the content of basalt fibers, some of the mechanical performances of the UHMWPE composites were excellently improved.

2010-12-28

National Natural Science Foundation of China (Grant No. 51075387

School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221116, China,School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221116, China,School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221116, China,School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221116, China,School of Materials Science and Engineering, China University of Mining & Technology, Xuzhou 221116, China

#Materials Science#

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