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

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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, China 2. Graduate School, lanzhou university, lanzhou 730000, China) Antai College of Economics & 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.

Microstructures and corrosion properties of casting in situ Al_3Ti-Al composites

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Rare Metals 2010年第1期29卷 78-85页

作者： CHEN Tijun LI Jian HAO Yuan Gansu Key Laboratory of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050 China School of Material Science and Engineering Xi＇an Shiyou University Xi ＇an 710065 China

The effects of Ti content and the alloying elements of Si and Cu on the microstructures of casting in situ Al3Ti-Al composites were investigated. Simultaneously, their corrosion properties were also discussed. The results indicate that the aspect ratios of Al3Ti platelets in different Al based composites are different although all of them are in flaky shape. The morphologies of Al3Ti phase are not only determined by Ti content, but are also related to the alloying elements. The grain refining role of Al3Ti phase in the pure Al and Al-Cu based composites is more effective than that in the Al-Si based composite. The addition of Ti decreases the corrosion resistance of pure Al and Al alloys. The corrosion resistances of the composites are dependent on both the corrosion characteristics of the corresponding matrixes and the distribution of Al3Ti platelets.

关键词： metal matrix composite microstructure corrosion resistance alloying element morphology

ASYMMETRIC　MICHAEL－TYPE　ALKYLATION　OF　CHIRAL　IMINES　DIASTEREOSELECTIVE　SYNTHESIS　OF（＋）－α－CYPERONE　AND　（－）－10－EPI－α－CYPERONE

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Chinese Chemical Letters 1996年第8期7卷 695-696页

作者： Zhao Ming XIONG Jiong YANG Yu Lin LI Ren An LIAO Zheng Ming LI(State Key Laboratory of Applied Organic Chemistry and Instute of Organic Chemistry, lanzhou university,lanzhou 730000, State Key Laboratory of Elemento-Organic Chendsny, Nankai university, State Key Lab. of Appl. Organ. Chem. Instute of Organic Chemistry Lanzhou University Lanzhou 730000 State Key Lab. Elemento-Organ. Chem. Nankai University Tianjin 300071

A novel diastereoselective route to (+)-a-cyperone(1) and (-)-10-epi-a-Cyperone(2) hasbeen developed. The key step involves an asymmetric Michael addition of the correSPonding chiralimine, derived from R-(+)-dihydroca... 详细信息

关键词： EPI ALKYLATION AND

A NEW ALKALOID FROM CELASTRUS ANGULATUS

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Chinese Chemical Letters 1993年第3期4卷 219-220页

作者： Yong Qiang TU Yu Xin CUI Yong Xiang MA Department of Chemistry,lanzhou university,lanzhou,730000

A new β-dihydroagarofuran alkaloid Ⅰ was isolated from Celastrus *** structure was established on the basis of 1D and 2D NMR analysis,and x-ray diffraction.

关键词： A NEW ALKALOID FROM CELASTRUS ANGULATUS

INTRA-ION PAIR ELECTRON TRANSFER OF PHOTOEXCITED METHYLENE BLUE BORATE

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Chinese Chemical Letters 1995年第7期6卷 597-600页

作者： Xiu Zhi WANG Han Qing CHEN Er Jian WANG (Institute of Photographic Chemistry, Academia Sinica, Beijing 100101National Laboratory of Applied Organic Chemistry, lanzhou university, lanzhou,730000) Acad Sinica Inst Photog Chem Beijing 100101 Peoples R China lanzhou Univ Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China

The photochemical reaction of methylene blue (n-butyltriphenyl) borate, MBRBPh3 was examined. The ultrafast quenching rate and large negative value of Delta G indicated that the intra-ion pair ET plays an important role in photoreaction of MBRBPh3. The sequent boron- carbon bond cleavage of butyltriphenylboranyl radical intermediate was found by GC-MS and photo-CIDNP studies.

关键词： ION INTRA-ION PAIR ELECTRON TRANSFER OF PHOTOEXCITED METHYLENE BLUE BORATE

Stereochemical Effects in Mass Spectrometry ( Ⅶ )——Negative Ion Fast Atom Bombardment Mass Spectro-metry of Saccharides with Areneboronic Acids as Reagents

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Chemical Research in Chinese Universities 1992年第3期8卷 231-238页

作者： YANG Hou-jun (Department of Chemistry, Tsinghua university, Beijing, 100084)CHEN Yao-zu (Department of Chemistry, lanzhou university, lanzhou, 730000)ZHAO Fan-zhi, LI Hai-quan, ZHAI Jian-jun and CHEN Nen-yu (Instrumental Analysis & Research Center, lanzhou university, lanzhou, 730000)

1-Naphthylboronic acid and 2, 4-dimethylphenylboronic acid can react stereospecif-ically with hydroxy groups of saccharides on the probe tip of a fast atom bombardment mass spectrometer to form characteristic negatively-charged boronate ions. On the basis of the relative abundances of these characteristic ions, the epimers of mono- and di-saccharides may be distinguished. This approach was proved to be a simple and effective means for identifying sugars. The collisional activation moss spectra of these characteristic ions are also discussed.

关键词： Reaction mass spectrometry Stereochemical effect Saccharides

Highly Stereoselective Synthesis of (E, E)-3,7-Dimethyl-2,6-decadiene-1,10-diol

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Chinese Chemical Letters 1999年第7期10卷 547-548页

作者： Zuo Sheng LIU Jiong LAN Li Zeng PENG Yu Lin LI Ya Cheng XING Wen CEN (National Laboratory of Applied Organic Chemistry and Institute of Organic Chemistry.lanzhou university lanzhou 730000Department of Chemistry, Qingdao university. Qingdao 266071) lanzhou Univ Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China lanzhou Univ Inst Organ Chem Lanzhou 730000 Peoples R China Ocean Univ Qingdao Dept Chem Qingdao 266071 Peoples R China

A total synthesis of (E,E)-3,7-dimethyl-2,6-decadiene-1,10-diol, using 1,3-transformation of 2, 3-epoxy alcohol and Claisen rearrangement of allyl vinyl ether as key steps, is described.

关键词： 2,3-epoxy alcohol 1,3-transformation : Claisen rearrangement synthesis

C_(14) ACETYLENES FROM ARTEMISIA FEDDEI^1

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Chinese Chemical Letters 1992年第4期3卷 283-284页

作者： Ren Xiang TAN, Zhong Jian JIA①and Yu ZHAO Institute of Organic Chemistry, lanzhou university, lanzhou 730000 Shi Lan FENG Department of Pharmacy, lanzhou Medical College, lanzhou 730000

The phytochcmical investigation of the aerial parts of Artemisia feddei Levl. et Vant. gave a pair of novel C_(14) acetylenic spiroketals.

关键词： pair ACETYLENES FROM ARTEMISIA FEDDEI~1

State Key Laboratory of Applied Organic Chemistry

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Progress in Natural Science:Materials International 2000年第3期 81-82页

作者： lanzhou university, lanzhou 730000, China

The State Key Laboratory of Applied Organic Chemistry (SKLAOC) was founded in 1987 withthe approval of the State Planning Commission. Professor Liu Zhongli is the director of the Laboratoryand Professor Zhang Lihe, an academician of the Chinese Academy of Sciences, is the chairman of itsacademic *** are 30 faculty members,among them 21 are professors,working in theLaboratory.

关键词： State Key Laboratory of Applied Organic Chemistry CIDNP