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AN INVESTIGATION OF FLOW CHARACTERISTIC OF AERATED DRAG REDUCTION IN TUBE

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Journal of Hydrodynamics 2002年第3期14卷 102-105页

作者： Dai Guang qing, Yang Qing State Key Hydraulics Laboratory of High Speed Flows, sichuan University, Chengdu 610065, ChinaZhang Rong Net Education Institute, sichuan University, Chengdu 610065, China Hydraulics Lab. of High Speed Flows Sichuan Univ. Chengdu 610065 China

Under the aerated conditions of wall and top in tube, the turbulent flow in the tube was measured by using LDA. The turbulent structure of the flow field and the mechanism of aerating drag reduction in the tube were discussed. It is shown that the energy dissipations of turbulence flow and mean flow will reduce and the flow velocity (or flow rate) will increase by injecting mini bubbles to the wall or top of tube, namely the effect of aerating drag reduction is attained.

关键词： tube turbulent flow aeration drag reduction

Theoretical analysis and experiment of micromechanics and mechanics-optics coupling of distributed optic-fiber crack sensing

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中国科学：技术科学英文版 2011年第S1期54卷 185-191页

作者： LIU HaoWu 1,2,CHEN Jiang 2,SUN Man 3 & DING Rui 2 1 State Key Laboratory of Hydraulics and Mountain River Engineering,sichuan University,Chengdu 610065,China 2 School of Water Resource Hydropower,sichuan University,Chengdu 610065,China 3 School Electrical Engineering and Information,sichuan University,Chengdu 610065,China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu China School of Water Resource Hydropower Sichuan University Chengdu China School Electrical Engineering and Information Sichuan University Chengdu China

The micromechanical behaviors and mechanics-optics coupling effects of optic-fiber-concrete complex in the distributed optic-fiber sensing concrete-crack technology,which was used in health monitoring of Wu Gorge Bridge on Yangtze River and a large dam successfully,have been investigated.A micromechanical theoretical analysis method and micromechanical frictional contact bi-interface model,as well as a modified optical theoretical analysis method of the mechanics-optics coupling effects are presented.A series of verification experiments,including mechanical experiments and mechanics-optics coupling experiments,have been *** results of micromechanical theoretical analysis and the analysis of the modified theory of mechanics-optics coupling along with mechanical and optical experimental data are shown to be in close *** the micromechanical theory and the modified theory of mechanics-optics coupling with their analysis methods can not only enhance credibility of this novel distributed sensing technology but also provide a way to understand its sensing mechanism and optimize its technical details and system.

关键词： optic-fiber sensing mechanics-optics coupling micromechanics health monitoring concrete structure crack detection

Autecology and conservation status of Magnolia sargentiana Rehder & Wilson(Magnoliaceae) in the Dafengding region,southern sichuan Province,China

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Journal of Systematics and Evolution 2009年第6期47卷 525-534页

作者： ~1Jing WANG ~1Ya TANG~* ~1Zheng-Hua XIE ~2Mian-Yue ZHANG 1(Laboratory for Biodiversity and Environmental Studies,Department of Environmental Sciences,sichuan University,Chengdu 610065,China) 2(Administrative Division of Mamize Provincial Nature Reserve,Leibo,sichuan 616550,China) (Laboratory for Biodiversity and Environmental Studies Department of Environmental Sciences Sichuan University Chengdu 610065 China) (Administrative Division of Mamize Provincial Nature Reserve Leibo Sichuan 616550 China)

This paper reports the first population ecology study of the endangered Magnolia sargentiana Rehder & Wilson(Magnoliaceae).Magnolia sargentiana is a protected species in China,but little is known about its present status in the *** 2007 and 2008,we surveyed the population and conservation status of *** in the Provincial Mamize Nature Reserve and the National Meigu Dafengding Nature Reserve,sichuan Province, southwestern *** regeneration is poor because of unfavorable environmental conditions and anthropogenic *** buds and bark *** are used in traditional Chinese medicine and their collection by local people over the period 1983-1994 has led to marked population *** collection of flower buds and bark is now banned,but hewing branches for firewood and grazing continues to have a negative impact on the recovery of *** *** protect the species,we require a ban on hewing branches,closure of primary forests to reduce the impact of humans and ungulates,better education of local people,and increased awareness of wildlife conservation.

关键词： Magnolia sargentiana medicinal plant plant conservation vulnerable species

Shape Memory Effect of As-aged Fe-14Mn-5Si-8Cr-4Ni-0.2C Alloy

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Journal of Materials Science & Technology 2000年第4期16卷 424-426页

作者： Yuhua WEN, Ning LI and Mingjing TU (Department of Materials Shaping and Controlling Engineering, sichuan University, Chengdu 610065, China) Department of Materials Shaping and Controlling Engineering Sichuan University Chengdu 610065 China

The effects of aging temperature on shape memory effect, mechanical properties and microstruc-ture of Fe-14Mn-5Si-8Cr-4Ni-0.2C shape memory alloy have been studied. The results showed that the second phase particles rich in chromium, manganese and silicon precipitate during aging, and thereby increase the hardness and strength of the alloy. The shape recovery ratio can be remarkably improved by aging and a maximum value can be obtained at 1223 K, which is 68% higher than that of the specimen in solid solution state. When the aging temperature is below 1223 K, the amount of second phase particles increases as the aging temperature increases. The size of austenite grain increases with increasing aging temperature. When the temperature is over 1223 K, the second phase particles can not precipitate. The lack of second phase particles and the increase of grain size make the hardness and shape recovery ratio drastically decrease, when the temperature is over 1223 K.

关键词： Mn Shape Memory Effect of As-aged Fe-14Mn-5Si-8Cr-4Ni-0.2C Alloy As Fe Cr Ni Si

CHARACTERISTIC ANALYSIS OF THE PLUNGING OF TURBIDITY CURRENTS

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Journal of Hydrodynamics 2010年第2期22卷 274-282页

作者： AN Rui-dong LI Jia State key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China College of Water Recourse and Hydropower Sichuan University Chengdu 610065 China

Turbidity currents are flows driven by suspended sediment of flood-induced turbid river water with excess *** currents are often the governing factor in reservoir sedimentation by transporting fine materials over long distances and delivering the majority of deposition,which thus reduces the storage ***,the design and operation of a reservoir requires an accurate prediction of its occurrence condition and plunging position,which is the objective of the present *** article presents a verified algebraic slip mixture model including momentum,continuity and algebraic velocity expressions to simulate 2-D turbidity *** experiments in a multiphase flume were carried *** number,sediment concentration and densimetric Froude number were used as parameters in the occurrence condition *** plunging of turbidity currents may produce reflux and backflow due to the diving flow at the surface of the clear *** similar experimental results were also obtained by PIV measurements

关键词： turbidity current plunge suspend sediment algebraic slip mixture model densimetric Froude number

Influence of La and RE on the Underside Shrinkage of ZA27 Alloy

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Journal of Rare Earths 1999年第2期17卷 47-51页

作者： Chen Yungui, Tu Mingjing, Shen Baoluo, Gao Shengji (Department of Metal Materials, sichuan University, Chengdu 610065, China) Department of Metal Materials Sichuan University Chengdu 610065 China

The effect of pure La and mischmetal(RE) on underside shrinkage of ZA27 alloy with cooling rate of 32 min-1 was investigated. The results show that the volumes of the underside shrinkage and the total shrinkage(underside shrinkage plus internal shrinkage) of the alloy decrease as the content of La or RE increases. When the contents of La and RE exceed 03%04%(mass fraction) respectively, the underside shrinkage is eliminated and the internal shrinkage moves upwards gradually. The mechanism that the underside shrinkage is eliminated is the falling of La and RE compounds and their accumulation on the bottom of the ZA27 alloy sample. Since La and RE can not effectively prevent phases(Al base solid solution) in the alloy from rising, the internal shrinkage is still close to the bottom of the ZA27 sample.

关键词： Rare earths Lanthanum Zinc base alloy Underside shrinkage

Effect of barium on the refinement of primary aluminum and eutectics in a hypoeutectic Al-Si alloy

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Rare Metals 2003年第3期22卷 192-196页

作者： LI Wei, FAN Hongyuan, ZHANG Xianju, and SHEN BaoluoSchool of Manufacturing Science and Engineering, sichuan University, Chengdu 610065, China School of Manufacturing Science and Engineering Sichuan University Chengdu 610065

The effect of barium on the refinement of primary aluminum and on themodification of eutectics in a hypoeutectic aluminum-silicon alloy was investigated. The resultsindicate that barium not only modifies the eutectic silicon but also refines the primary aluminumand there is a relationship between the retained barium and the second spacing of primary *** of barium-treated commercial Al-Si hypoeutectic alloy show that barium is a bettermodifier than sodium when there is a longer holding time.

关键词： non-ferrous metal barium modification primary aluminum eutectic Al-Sialloy

Characterization of the Microstructure Changes of Polypropylene Induced by Pan-milling

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Chinese Journal of Structural Chemistry 2002年第1期21卷 7-12页

作者： LU Can-Hui WANG Qi ( The state Key Laboratory of Polymer Materials Engineering, Polymer Research Institute, sichuan University, Chengdu 610065 ) Polymer Research Institute Sichuan University The State Key Laboratory of Polymer Materials Engineering Chengdu 610065

The microstructure changes of polypropylene induced by a complex combination of shearing, friction, compression and stretching actions during pan-milling were revealed by spectroscopic techniques. X-ray diffraction analysis showed that the structure of polypropylene transferred from crystal into amorphous after undergoing enough milling operation. No transformation between crystal forms was observed. The study of the high-frequency region of the Raman spectrum between 2800 and 3100cm-1 of polypropylene indicated that molecular motion and chain deformation of PP led to amorphization and deterioration of packing regularity during pan-milling. By co-panmilling PP with bis-(2,2,6,6-tetramethyl-4-piperidinyl) sebacate under ambient condition, ESR signals of free radicals formed by mechanochemical scission of main chain were observed, and an increase of ESR intensity with milling was detected.

关键词： polypropylene microstructure change mechanochemistry pan-milling

FUZZY NEURAL NETWORK FOR MACHINE PARTS RECOGNITION SYSTEM

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Chinese Journal of Mechanical Engineering 2003年第3期16卷 334-336页

作者： Luo XiaobinYin GuofuChen KeHu Xiaobing Luo YangInstitute of CAD&CAM,sichuan University,Chengdu 610065, China Institute of CAD&CAM Sichuan University Chengdu 610065

The primary purpose is to develop a robust adaptive machine parts recognitionsystem. A fuzzy neural network classifier is proposed for machine parts classifier. It is anefficient modeling method. Through learning, it can approach a random nonlinear function. A fuzzyneural network classifier is presented based on fuzzy mapping model. It is used for machine partsclassification. The experimental system of machine parts classification is introduced. A robustleast square back-propagation (RLSBP) training algorithm which combines robust least square (RLS)with back-propagation (BP) algorithm is put forward. Simulation and experimental results show thatthe learning property of RLSBP is superior to BP.

关键词： Fuzzy neural network Image processing RLSBP algorithm Machine partsclassification