检索结果-南通市图书馆

Dynamic learning rates algorithm for BPNN to forecast time series of dam security

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第12期17卷 1527-1530页

作者： Hu Daiping1. Wu Ruiming1. Lei Aizhong1.and Wang Qi2(1. Antai College of Economics & Management, Shanghai Jiaotong university, Shanghai 200052,{1. 2. Graduate School, lanzhou university,{3.,{1.) Antai College of Economics and Management Shanghai Jiaotong University Shanghai 200052 China Graduate School Lanzhou University Lanzhou 730000 China

Time series data of dam security have a large number of observed values and should be forecasted accurately in time. Neural networks have the powerful approach ablilities of arbitrary functions and have been broadly utilized in many domains. In this paper, a dynamic learning rate training algorithm of back-propagation neural networks for time series forecasting is proposed and the networks with this algorithm are built to forecast time series of dam security. The application results demonostrate the efficiency of modelling and the effictiveness of forecasting.

关键词： neural network dynamic learning rate forecasting dam security.

Probing Nuclear Symmetry Energy with Giant Dipole Resonances in Finite Nuclei

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

原子核物理评论 2009年第S1期26卷 181-184页

作者： CAO Li-gang1.3.MA Zhong-yu2,3.(1.Institute of modern physics,Chinese Academy of Sciences,lanzhou {3.,china 2 china Institute of Atomic Energy,Beijing 1.241.0}china 3.Center of Theoretical Nuclear physics,National Laboratory of Heavy Ion Research Facility in lanzhou,lanzhou {3.,china) Institute of modern {1. Chinese Academy of SciencesLanzhou 730000China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China china Institute of Atomic Energy Beijing 102413China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China

The relationship between the centroid energies of the isovector giant dipole resonance of finite nuclei and the symmetry energy has been studied. It is found the excitation energies of the dipole resonance in finite nuclei are correlated linearly with the symmetry energy at and below the saturation density. This linear correlation leads to the symmetry energy at the saturation density at the interval 3..0 MeV ≤ S(ρ0) ≤ 3..0 MeV,and the symmetry energy at ρ = 0.1.fm-3.at the interval 21.2-22.5 MeV. It is proposed that a precise measurement of the dipole mode in nuclei could set up an important constraint on the equation of state for nuclear matter.

关键词： symmetry energy dipole resonance Pygmy resonance

Study on the Reaction of Proteins with 5-Nitrosalicylfluorone-molybdenum(Ⅵ) Complex by Spectrophotometry in PVA 1.4 Microemulsion

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2004年第7期22卷 714-718,615页

作者：魏琴吴丹杜斌张慧欧庆瑜lanzhou Institute of Chemical {1. Chinese Academy of Sciences lanzhou Gansu {3. china School of Chemistry & Chemical Engineering Jinan University Jinan Shandong 250022 China Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou Gansu 730000 China School of Chemistry & Chemical Engineering Jinan University Jinan Shandong 250022 China

The application of 5'-nitrosalicylfluorone (5'-NSF)-molybdenum(VI) complex as a spectroscopic probe was studied. In the buffer medium of HOAc-NaOAc at 3.45 and in the presence of PVA 1.4 microemulsion, 5'-NSF-Mo(VI) complex combines protein rapidly to form a stable compound, leading to an absorbance decrease at 525 nm of 5'-NSF-Mo(VI) complex. According to this change, microdetermination of protein has been described. Bovine serum albumin (BSA) could be determined in the linear range of 0—1. g昺L-1.with the detection limit of 1. ngmL-1. Many amino acid and metal ions studied do not interfere with the assay. The method possesses high sensitivity as well as high selectivity. It can be used to determine protein in human urine and milk powder successfully. The relative standard deviations are in all instances less than 4.7%, and the recoveries are between 97.6% and 1.6.0%. Moreover, the binding number of BSA with the complex, which is determined by using molar ratio, Rosenthanl graphic and slope ratio methods, is in good agreement with each other.

关键词： protein spectrophotometry 5'-NSF-Mo(VI) complex microemulsion

Numerical study on short-circuit current of single layer organic solar cells with Schottkey contacts

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第4期53卷 1023-1027页

作者： MA ChaoZhu1.MENG WeiMin2,PENG YingQuan1.2,WANG RunSheng1.LI RongHua1.XIE HongWei1.WANG Ying1.& YE ZaoChen1.1.Institute of Microelectronics of School of Physical Science and Technology,lanzhou {1.,lanzhou {3.,china 2 Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,lanzhou {1.,lanzhou {3.,china Institute of Microelectronics of School of Physical Science and Technology Lanzhou University Lanzhou China Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education Lanzhou University Lanzhou China

The influence of the cathode work function,carriers mobilities and temperature on the short-circuit current of single layer organic solar cells with Schottkey contacts was numerically studied,and the quantitative dependences of the short-circuit current on these quantities were *** results provide the theoretical foundation for experimental study of single layer organic solar cells with Schottkey contacts.

关键词： cathode work function carrier mobility temperature short-circuit current

The characteristic spectral lines of target atoms in the impact of^(40)Ar^(q+)ions on metal surfaces

在线全文

学校读者我要写书评

暂无评论

Science china({1.,Mechanics & Astronomy) 2004年第6期47卷 729-736页

作者： ZHANG Xiao’an1.2,ZHAO Yongtao1.2,LI Fuli1.YANG Zhihu2,XIAO Guoqing2 & ZHAN Wenlong2 1.Department of Applied physics,Xi’an Jiaotong {1.,Xi’an 71.049,china 2.Institute of {3. physics,Chinese Academy of Sciences,lanzhou 730000,china Department of Applied physics Xi'an Jiaotong University Xi'an 710049 China Institute of modern {1. Chinese Academy of Sciences Lanzhou 730000 China

We report the measured results of the 200 nm—1.00 nm characteristic spectral lines of target atoms when highly charged ions40Ar q+(6≤q≤1.) with the same kinetic energy and40Ar6+ with different kinetic energies are incident upon Al, Ti, Ni, Ta and Au surfaces, respectively. The results for1.9Xe6+,1.9Xe1.+ and1.9Xe1.+ with the same kinetic energy (1.0 keV) incident upon a Ta surface are also reported. These results show that when the projectile and target are properly selected (40Ar1.+ impinges on Al,1.9Xe6+ impinges on Ta), the spectral intensity of characteristic spectral lines of the target atom is effectively enhanced, and is not strongly dependent on the kinetic energy of the incident ions.

关键词： highly charged ion, hollow atom, characteristic spectrum, spectral intensity.

Friction-reducing and antiwear behavior of metal halide-stabilized linear phosphazene derivatives as lubricants for a steel-on-steel contact

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2005年第3期48卷 282-291页

作者： ZHU Jiamei 1.2 , LIU Weimin 2 & LIANG Yongmin 2 1. School of Chemical Engineering and Technology, china {1. of Mining and Technology, Xuzhou 221.08, china 2. State Key Laboratory of Solid Lubrication, {3. Institute of Chemical physics, Chinese Academy of Sciences, lanzhou 730000, china School of Chemical Engineering and Technology China University of Mining and Technology Xuzhou China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou China

A series of novel metal halide-stabilized linear phosphazene derivatives were synthesized. The friction-reducing and antiwear abilities of the resulting products as the lubricants for a steel-on-steel contact were comparatively investigated on an Optimol SRV oscillating friction and wear tester. The morphology of the worn steel surface was observed on a scanning electron microscope, while the chemical states of some typical elements on the worn steel surface were examined by means of X-ray photoelectron spectroscopy. It was found that both the side branch structures and central metals influenced the friction-reducing and antiwear behaviors of the synthetic derivatives as the lubricants, which was related to the different adsorption activities of the organic compounds composed of different organic ingredients and metallic ions on a nascent metal surface. All the synthetic lubricants except for the iron (III) derivative showed increased antiwear abilities with increasing metallic ionic radius. A protective layer originated from the tribochemical reaction together with the adsorbed boundary lubricating layer containing organic fluorine compounds, nitrogen oxide, and Fe 3.(PO 4 ) 2 plays an important role in improving the friction and wear behavior of the steel-on-steel system.

关键词： metal halide-stabilized linear phosphazene derivatives,lubricant,steel,tribological properties.

Vicissitude of Sogo Nur and environmental-climatic change during last 1.00 years

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2004年第Z1期47卷 61-70页

作者： JIN Heling, XIAO Honglang, SUN Liangying, ZHANG Hong, SUN Zhong & LI XiaozeKey Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, lanzhou 730000,{1. School of Resources and Environment, lanzhou university, lanzhou 730000,{1. Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China School of Resources and Environment Lanzhou University Lanzhou China

Lakes in arid zone are sensitive to climatic changes. The lacustrine sediment sequence in Sogo Nur has well and truly recorded climatic events such as the Sui-Tang Dynasty Warm Period, the Song-Liao Dynasty Cold Period, the Medieval Warm Period, the Little Ice Age and the 20th Century Warm Period. Commonly, the climate in warm Periods was relatively humid,accordingly the lake area extended and water level rose, and vice versa. Apart from climatic change, human activity is also an important factor of influencing lake vicissitude, and they played the dominant role alternatively during different periods; the factor of climatic change predominated in historical period, while since the beginning of the 20th century the utilization of water resources by human has became decisive.

关键词： granularity, soluble salt, lake vicissitude, climatic change, Sogo Nur.

Development of a Chinese land data assimilation system:its progress and prospects

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第8期17卷 881-892页

作者： Li Xin~(1.*) Huang Chunlin~1.Che Tao~1.Jin Rui~1.Wang Shugong~l Wang Jiemin~1.Gao Feng~1.Zhang Shuwen~2 Qiu Chongjian~2 Wang Chenghai~2 (1.Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,lanzhou {1.,china 2.College of Atmospheric Sciences,lanzhou university,lanzhou {1.,china) Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China College of Atmospheric Sciences Lanzhou University Lanzhou 730000 China

The objective of land data assimilation is to merge multi-source observations into the dynamics of land surface model for improving the estimation of land surface *** have developed a land data assimilation system for china's land *** this sys- tem,the Common Land Model and Simple Biosphere Model 2 are used to simulate land surface *** radiative transfer models of thawed and frozen soil,snow,lake,and vegetation are used as observation operators to transfer model predictions into estimated bright- ness temperatures.A Monte-Carlo based sequential filter,the ensemble Kalman filter,is implemented as data assimilation method to inte- grate modeling and *** system is capable of assimilating passive microwave remotely sensed data such as special sensor mi- crowave/imager (SSM/I),TRMM microwave imager (TMI),and advanced microwave scanning radiometer enhanced for EOS (AMSR- E) and the conventional in situ measurements of soil and snow.A spatiotemporally consistent assimilated dataset for soil moisture,soil temperature,snow and frozen soil,with a spatial resolution of 0.25 degree and temporal resolution of one hour,has been *** paper introduces the development of Chinese land data assimilation system and the progress made on data assimilation algorithms,land sur- face modeling,microwave remote sensing of land surface hydrological variables,and the preparation of atmospheric forcing *** dis- tinct characteristics and challenges of developing land data assimilation system and the perspectives for future development are also dis- cussed.

关键词： land data assimilation land surface model passive microwave remote sensing Kalman filter

Charmed Baryon in Diquark Model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

原子核物理评论 2009年第S1期26卷 190-193页

作者： WANG Qing-wu1.3. ZHANG Peng-ming1.2(1.Institute of {1. physics, Chinese Academy of Sciences, lanzhou 730000,{3. 2 Center of Theoretical Nuclear physics, National Laboratory of Heavy Ion Research Facility in lanzhou,lanzhou 730000,{3. 3.Graduate School of Chinese Academy of Sciences, Beijing 1.0049,{3.) Institute of modern {1. Chinese Academy of SciencesLanzhou 730000China Graduate School of Chinese Academy of Sciences Beijing 100049China Institute of modern {1. Chinese Academy of SciencesLanzhou 730000China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China

A diquark model is used to investigate single-charmed baryons. In this model,baryon is composed of two diquarks and an antiquark. Masses of lowest lying states with JP=1.2± are obtained. Baryons in our results are as heavy as other theoretic predictions and we suggest that the five-quark components should be considered in any three-quark model for studying the charmed baryons.

关键词： charm diquark pentaquark