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Torque model of hydro turbine with inner energy loss characteristics

Science china(Technological sciences) 2010年第10期53卷 2826-2832页

作者： ZENG Yun1,2, GUO YaKun2, ZHANG LiXiang1, XU TianMao3 & DONG HongKui4 1 Construction Engineering College, Kunming university of Science and Technology, Kunming 650051, china 2 School of Engineering, university of Aberdeen, Aberdeen AB24 3UE, UK 3 Computing Center, Kunming university of Science and Technology, Kunming 650051, china 4 Hydraulic Energy department, Yunnan Electric Power Test and Research Institute, Kunming 650217, china 1. Construction Engineering College Kunming University of Science and Technology Kunming 650051 China2. School of Engineering University of Aberdeen Aberdeen AB24 3UE UK3. Computing Center Kunming University of Science and Technology Kunming 650051 China4. Hydraulic Energy Department Yunnan Electric Power Test and Research Institute Kunming 650217 China

This paper presents the result and analysis of the composition of energy loss occurring in the hydro turbine. Two new types of energy losses,namely the hydraulic loss in the flow channel and the impact loss,are defined. All losses within the hydro turbine are divided into four types and the loss coefficients are defined accordingly. Expressions or characteristic descriptions of these losses as well as the calibration method of the loss coefficients are presented. Furthermore,the torque model of the hydro turbine where the inner energy loss takes place is established. The developed model has been used to calculate the power loss due to the mechanical friction generated by the units’ rotation to solve the difficulty of measurements of the mechanical friction loss in the hydro turbine. The definition of the impact loss explains the phenomenon that the loss of no-load is greater than that of the rated operation. A set of conversion coefficients are defined using the characteristic parameters at the rated operation,which are used to transform the parameters in the torque model into those that are easily measured. Therefore,the expression of the hydro turbine power is converted into a function that has the main servomotor displacement as its single variable. This makes the proposed model be convenient to use. Finally,the proposed model and methods are calibrated and verified using the measured data of a hydropower plant. Good agreement between the modeled results and the measurements indicates that the proposed model can represent the inner energy loss characteristics of the hydro turbine.

关键词： hydraulic loss in flow channel impact loss loss coefficients conversion coefficients

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DYNAMIC MECHANICAL BEHAVIOR OF Fe_3Al UNDER TENSILE IMPACT

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中国有色金属学会会刊：英文版 1999年第S1期9卷 138-141页

作者： Yanxiong Liu 1, Yuanming Xia 1, Mingwei Chen 2 and Dongliang Lin 2 1 department of Modern Mechanics, university of Science and Technology of china, Hefei 230027, china 2.department of Materials Science, Shanghai Jiao Tong university, Shanghai 20

The loading tests of Fe 3Al under tensile impact have been carried out by a self designed rotating circular disk tensile impact apparatus. An experimental study of Fe 3Al in the strain rate range from 80 s -1 to 1 200 s -1 was performed and the complete stress strain curves under tensile impact were obtained. On the basis of the experimental results, it is believed that Fe 3Al obviously exists dynamic ductility and effect of strain rate hardening. The yield strength, ultimate strength and failure strain increase with increasing strain rate. Based on the linear least squares fit, the relationship between the yield strength, ultimate strength, failure strain and strain rate under tensile impact was obtained. At the same time, one dimensional macro constitutive equation for Fe 3Al under tensile impact according to the elastic viscoplastic constitutive theory was derived.

关键词： Fe 3Al tensile impact dynamic ductility strain rate hardening

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Review on theoretical studies of superheavy nuclei

Review on theoretical studies of superheavy nuclei

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International Conference on Nuclear Structure Physics

作者： Zhongzhou Ren and Chang Xu department of Physics nanjing university nanjing 210008 china Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 china

＜正＞Research on superheavy nuclei is one of the hot points in nuclear physics [1-4]. We review the current theoretical studies on superheavy nuclei. The structure and decay of heavy and superheavy nuclei are systematically studied by different models [5-13]. New models of α-decay half-lives and new formulae for nuclear binding energies and spontaneous fission half-lives are presented [7-10]. The theoretical results are in good agreement with available data of heavy and superheavy nuclei. The properties of unknown superheavy nuclei are predicted.

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Effect of different fertilizers on methane emission from a paddy field of Zhejiang, china

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Journal of Environmental sciences 1999年第4期11卷 457-461页

作者： Ibrahim Traore, SHEN Dong\|sheng, MIN Hang, CHEN Mei\|ci, FENG Xiao\|shan (department of Environmental sciences, Zhejiang university,Hangzhou 310029, china) 浙江大学环境保护系浙江杭州浙江农业大学环境保护系浙江杭州

Methane emissions from Chinese paddy soil (Zhejiang Province) were measured over the rice growing seasons. Different fertilizers (organic and chemical) were applied, emissions of methane were high during two periods(5 days after peak tillering and 7 days after heading flowering stage) and significant effect of fertilizers was observed. Methanogenic activities in soils treated with organic manures were obviously higher than those with chemical fertilizers. Among the organic manured fields the maximum methane emission from green manure, biogas residue and beef manure treatment were 52, 20 and 19 times respectively of that given by control, and among chemical fertilizers it was NH\-4HCO\-3>CO(NH 2) 2>(NH 4) 2SO 4>NH 4Cl>NaNO 3 with 2\^4, 2, 1\^5,1\^3 and 0\^2 times respectively of that from control.

关键词： methane emission field methanogenic flora flooded rice organic and chemical fertilizer

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Spatial hearing model based on spatial feature extraction and artificial neural network

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Chinese Journal of Acoustics 2000年第2期19卷 123-127页

作者： WU Zhenyang WANG Weibin (department of Radio Engineering Southeast university nanjing 210018)

In spatial hearing, complex valued head-related transfer function (HRTF) can be represented as a real valued head-related impulse response (HRIR). By using Karhunen-Loeve expansion, the spatial features of the normalized HRIRs on measurement space can be extracted as spatial character functions. A neural network model based on Von-Mises function is used to approximate the discrete spatial character function of HRIR. As a result, a time-domain binaural model is established and it fits the measured HRIRs well.

关键词： HRTF HRIR MSE

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Microwave propagation in air drilling

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Petroleum Science 2010年第3期7卷 390-396页

作者： Meng Xiaofeng Chen Yijian Zhou Jing Meng Yingfeng Physics department Beijing Normal University Beijing 100875 China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Chengdu Sichuan 610500 China

This paper examines the feasibility in air drilling of transmitting down-hole signals by using microwaves. Firstly the basic theory of microwave propagation in the drill-pipe or casing was studied, including power loss, cutoff wavelength, and dust scattering. Theoretical analysis indicates that the microwave propagation distance in a cb214mm casing can easily reach 5,000 m. When the effect of dust particles is taken into account, the propagation distance decreases to 2,000 m. We conducted both laboratory experiments and field tests in casings commonly used in oil fields. The field tests show that the effective propagation distance of microwave in the casing is about 1,300 m. The experimental results do not match well with theoretical prediction, but are acceptable. In future commercial applications, by applying multiple relay amplifiers, the microwave propagation distance could be long enough for most drilling wells.

关键词： Microwave waveguide drill-pipe casing air drilling

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Interactions of Marsh Orchid(Dactylorhiza spp.)and Soil Microorganisms in Relation to Extracellular Enzyme Activities in a Peat Soil

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Pedosphere 2007年第6期17卷 681-687页

作者： H. KANG C. FREEMAN department of Civil and Environmental Engineering Yonsei University Seoul 120- 749 （Korea） School of Biological sciences University of Wales Bangor LL57 2UW （UK）

The nature of the interactions between microbes and roots of plants in a peaty soil were studied in a laboratory- based experiment by measuring activities ofβ-glucosidase,phosphatase,N-acetylglucosaminidase,and *** experiment was based on control(autoclaved),bacteria-inoculated,and plant(transplanted with Dactylorhiza)treatments, and samples were collected over 4 sampling *** enzyme activities were associated with the bacteria-inoculated treatment,suggesting that soil enzyme activities are mainly of microbial *** example,β-glucosidase activity varied between 25-30μmol g^(-1)min^(-1)in the bacteria-inoculated samples whilst the activity of the control ranged between 4-12μmol g^(-1)min^(-1)A similar pattern was found for all other enzymes. At the end of the incubation,the microcosms were destructively sampled and the enzyme activities determined in bulk soil,rhizospheric soil,and on the root *** measurement in different fractions of the peat indicated that higher activities were found in ***,the higher activities ofβ-glucosidase,N-acetylglucosaminidase,and arylsulphatase appeared to be associated with bacterial proliferation on the root surface,whilst a larger proportion of phosphatase appeared to be released from root surface.

关键词： Dactylorhiza extracellular enzyme peat rhizosphere wetland

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Two Families of Liapunov Functions for Functional Differential Systems

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Acta Mathematica Sinica,English Series 1999年第2期15卷 197-206页

作者： Yi Zhang, department of Computer Science and Engineering, university of Electronic Science and Technology of china, Chengdu 610054, P. R. chinaMeijuan Wang, department of Basic Studies, East china university of Technology, 516 Jungong Road Shanghai 2.0093, P. R. china department of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu P. R. China department of Basic Studies East China University of Technology Shanghai P. R. China

Two families of Liapunov functions are employed to study the global stability and bound- edness of functional differential systems. New stability and boundedness theorems are obtained. Ap- plications of these theorems... 详细信息

关键词： Liapunov Function Razumikhin Technique Stability Infinite Delay

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A theoretical model of electrostatic ultrasonic transducers with micro air-gap structure

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Chinese Science Bulletin 1998年第9期43卷 728-731页

作者： GE Lifeng (GE Li-Feng) department of Physics, Anhui university, Hefei 230039, china department of Physics Anhui University Hefei China

A new plate-on-air-spring model (or called short tube or DK model) for modelling the behaviour of electrostatic air-coupled ultrasonic transducers is developed and verified by accurate predictions of natural frequenci... 详细信息

关键词： electrostatic ultrasonic transducer micro air-gap structure modelling.

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Sensory control of lipid accumulation in nematode Caenorhabditis elegans

Sensory control of lipid accumulation in nematode Caenorhabd...

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中国遗传学会“发育、遗传和疾病”研讨会

作者： Xuemei Xu~(+++) Dayong Wang~(+++) +department of Genetics and Developmental Biology,Southeast university,nanjing 210009,china ++Key Laboratory of Developmental Genes and Human Disease in Ministry of Education,Southeast university,nanjing 210009,china

Body fat regulation is a complex process that affects behavior,physiology,and metabolism of an organism in order to balance energy intake with energy *** alarming worldwide increase in obesity has intensified the search to identify genes that control the development,differentiation,and function of fat-storing *** elegans is an attractive choice for the systematic identification of components of fat *** using RNA-mediated interference(RNAi)to disrupt the expression of each of the 16,757 worm genes,Ashrafi et al.(2003)have systematically screened the C. elegans genome for genes necessary for normal fat ***,many other nematode genes controlling the body fat still remain to he identified,since not all genes would be responsive to the RNAi *** the current work,mutations of 47 genetic loci controlling the cilia structure,and functions of sensory and interneurons were screened for the possible lipid accumulation defects compared to wild-type by using Sudan black and Nile Red staining to visualize the fat *** of 16 genetic loci(tax-2,tax-4,daf-11,daf-21,the-1,ttx-1,osm-9,daf-2,gpc-1,daf-7,gcy-5,ttx-3,the-13,daf-10,osm-1 and osm-6)increased the fat storage,whereas mutations of 3 genetic loci(tax-6,che-11 and osm-3)reduced the lipid *** addition,mutations of genes of daf-21,tax-6,tax-4,the-13 and osm-6 also results the defects of body bends,and/or head thrashes,and/or brood size,and/or the number of eggs in *** interaction assay further indicated that TGF-beta signaling act upstream of most of these identified genes,and daf-lO,daf-11,daf-21,che-1,gcy-5,ttx-3,che-13,osm-1 and osm-6 functions upstream of the insulin signaling by interacting with the daf-2 and daf-16,respectively,to regulate the lipid ***,the genes involved in the sensory control of lipid accumulation and the pathways mediated by these genetic loci were identified and elucidated in ***

关键词： lipid accumulation sensory control genetic interaction C.elegans

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