Kang Zhengjiu, Shi
Yiming, Hu Baosheng
(Xi'an Jiaotong University, 710049 Xi'an)
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Abstract: Based on inverse QR method for recursive least squares parameter, a new method for recursive total least squares parameter estimation is presented .Moreover, a Systolic array for parallel implementation is sh own and simulation results are given at the end. The parallel iterative method makes the total least squares parameter estimation feasible in practice.
Keywords: total least squares, parameter estimation,parallel algorithm, Systolic array
Tang Benqi, Gao Yumin,
Luo Jinsheng
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract: The effects of lateral
radius of window curvature on the breakdown voltage of FLR's are analyzed and discussed by
analytical approach for the first time,and the normalized expression of the breakdown
voltage of planar junctions terminated with a single optimally placed FLR, and the
equation to determine the optimal spacing of the field ring are derived. The accuracy of
analytical expressions is verified by comparison with the quasi-3D numerical simulation
results in the published papers. This approach can be used directly and conveniently in
the optimum design for FLR's structure.
Keywords: field limiting
ring, lateral radius, breakdown voltage, spacing of rings
Zhao Yuqing, Yu Zhijun
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract: The geometry
construction and electrode voltages of ion source extraction system are optimized by using
the combined method of Powell method and simulated annealing method (PSAM). Owing to
adapting correct calculation method and effective optimal strategy, PSAM can decrease
greatly CPU time and be implemented on the microcomputer. Our practice shows that PSAM is
a practical global optimization method. It can be widely applied in the inverse problem of
electromagnetic fields and construction optimization of electric equipment.
Keywords: optimal design,
extraction system, ion source
Zhai Jiwei, Zhang
Liangying, Yao Xi
(Xi'an Jiaotong University, 710049, Xi'an)
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Abstract: The silica based
nanocomposite films were fabricated by solgel method. FT-IR analysis indicated that the
hydroxy was removed in films when heat treatment temperature was increased. The hydroxy
was obviously decreased by adding CCl4 during the heat treatment. The SEM and EDS analysis
revealed the submicrometer scale inhomogeneity on the surface film. In the inhomogeneous
region, the content of carbon is higher than that of homogeneous region. Through the heat
treatment at 800¡æ for 15 min in O2 the inhomogeneous
region disappeared. X-ray glancing incidence analysis indicated that the crystal grain
size decreased along the thickness of the thin film. With heat treatment temperature
increased, the difference of crystal grain size along the thickness was enhanced
Keywords: sol-gel,
film, hydroxy, grain size distribution
Tian Yuan, Liang Dequn
(Xi'an Jiaotong University, 710049, Xi'an)
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Abstract: A new method to locate
and segment human faces in a complex background is proposed. This system utilizes a
hierarchical knowledge based method and consists of three levels. The higher two levels
are based on detecting maximum (corresponding to faces) and minimum(corresponding to eyes)
inmultiresolution image using spline dyadic wavelet transform, and then initial selection
is made using some know- ledge e.g. the relation of scale between eyes and face, symmetry
of face, etc. The last level will make the face and eyes certainly according to the
features of face. This method can locate and segment unknown human faces spanning a wide
range of sizes in an intensity image. Some experimental results are presented
Keywords: face detection,
knowledge-based pattern recognition, multiscale ridge
Li Luping, Luo Jian,
Cheng Jingzhi
(Xi'an Jiaotong University, 710049, Xi'an)
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Abstract: Estimating the useful brain
signal from a single recorded data is aimed at to correct the possible error introduced
with the averaging techniques. Combining the correlation analysis, a new approach to
extract single trial event-related potential (ERP) is proposed. This approach, called time
frequency filter, is based on the concept of multiresolution wavelet transform. An
investigation into properties in time and frequency domain was carried out on the single
ERP and average ERP. The results from a large amount of test show that wavelet timeª²frequency
filter can effectively extract the single ERP from strong background noise
Keywords: wavelet transform, time-frequency filter,
event related potential, single-trial extracting
Cao Jianfu, Han
Chongzhao
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract: Based on
generalized frequency response functions, the parametric stability domain for a class of
nonlinear control system¡¡is discussed, and a new frequency stability
criterion is proposed. Finally, this criterion is demonstrated by a simulation example.
Keywords: nonlinear
control system, generalized frequency response function, stability
กก
Gan Wenquan, Wang
Zhaohui, Hu Baosheng
(X'ian Jiaotong University, 710049, Xi'an)
[Return]
Abstract: This
paper presents a hybrid model for short-term load forecasting that integrates artificial
neural networks (ANN) and fuzzy expert system. Radical basis function(RBF) network is
introduced and an orthogonal least square alogorithm (OLS) is used to determine RBF
function centers. The initial load is forecasted by the trained RBF networks, and then,
the fuzzy expert systems modify the initial load considering the possibility of load
variation due to changes in temperature and the load behavior of holiday. Day-types are
divided into five classes in this paper. Test results show that the hybrid model can
forecast load with a higher accuracy and a faster speed.
Keywords: load
forecasting, ANN, RBF, OLS, fuzzy expert system
A Hybrid Genetic-Based Parametric Synthesis for Classifier
Gao Chunhua, Li Renhou
(Xi'an Jiaotong University, 710049, Xi'an)
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Abstract:
Concerning classifier problem, which is a pattern recognition problem in narrow sense,
this paper analyzed the complexity of implementation based on multiª²layer
forward neural network(MFNN), and proposed a hybrid method of genetic algorithm(GA) and
mathematical programming to train weight distribution for parametric synthesis of
classifier. At the last, the results of simulation test were described.
Keywords: pattern
classifier, neural network, genetic algorithm, nonlinear programming
Study on Hydrodynamic Characteristics of Oil-Gas-Water Three-Phase Slug Flow in Vertical Tubes
Wang Yueshe, Wei
Xiaojin, Zhou Fangde
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
With the high speed motion analyzer and the optical-fiber void fraction measurement
device, an experimental study on hydrodynamic characteristics of oil- gas-water
three-phase slug flow in vertical tubes has been made. The results showed that
short-time-averaging void fraction is an effective method for flow pattern recognition.
And by changing the ratio of water to oil in the threeª²phase flow system, its
influence on averaging void fraction was found out. Finally, averaging liquid lengths were
also obtained in each case with the high speed motion analyzer
Keywords: three-phase
flow, slug flow, void fraction, liquid slug
A Model for Predicting Slug Frequency Based on Growingof Finite-AmplitudeInterfacial Wave
Liu Lei, Liu Yun, Zhou
Fangde
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
A model for predicting slug frequency of horizontal slug flow was derived based on the
concept of equilibrium liquid film and the potential analysis for finite-amplitude
interfacial wave in stratified flow. Slug formation due to bridging the up wall of
horizontal pipe by growing interfac ial wave was assumed. Slug frequencies of air-water
flow were measured by elect rical probe in a horizontal pipe with a diameter of 24mm, and
the ratio of l ength to diameter over six hundreds. The predicted results agree well with
the test data.
Keywords: two-phase
flow, slug flow, interfacial wave, frequency, horizontal pipe
Non- Linear Analysis of the Interfacial Stability of Gas-Liquid Two- Phase
Separated Flow
Li Guangjun, Guo Liejin, Chen Xuejun
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract: From the complete two-fluid
modeling equations of gas-liquid twoª-phase separated flow, a set of non-linear
hyperbolic governing equations were deduced by omitting the effect of the surface tension
and assuming a quasi- steady-state for the gas phase. These characteristic equations were
solved by using characteristic line and finite difference. The propagation and growth of
the interfacial disturbances in space with time were investigated by using the numerical
results in terms of gas and liquid superficial velocities. The comparisons of the
non-linear stabili- ty results with those of the linear stability analysis and
experimental data showed that the nonª²linear stability analysis not only can
confirm the conclusions based on the linear stability analysis, but also can give an
insight into the growth and propagation of the interfacial disturban- ces on the interface
of gas-liquid two-phase flow.
Keywords: gas-liquid
two-phase flow, interfacial stabilities, non-linear stability analysis, characteristic
line, finite difference
Analyzing
the Mechanics Characteristics of Turbine Long Blade by Using the Complete Bending-Twisting
Beam Finite Element Method
Zhu Baotian, Wu Houyu
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract: In the paper£¬ the
static and dynam ic characteristics of the 680 mm blade,905 mm blade and 851 mm blade are
calculated and analyzed by using the complete bending-twisting beam finite element model
and method. The calculating results are in agreement with experiment.It shows that the
proposed model and method have their engineering application value
Keywords: FEM,
turbine blade, coupled ben ding-twisting, stress,frequency
Modifed
QUICK Scheme and Its Application
in Slug Flow
Wei Xiaojin, Wang Yueshe, Zhou Fangde
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
An non-uniform grid based scheme-modified QUICK has been developed. Calculations of
several classic questions in numeric al heat transfer show good agreement. Using the QUICK
and the well known SIMPLEC method, flow field around Taylor bubbles in upward flow and the
reason- able sh ape and velocity have been figured out
Keywords: slug
flow, Taylor-bubbles, QUICK scheme, SIMPLEC method
Pool
Boiling of R134a outside a Horizontal Enhanced Tube
Li Fangming, Li Peiwen, Li Wu, Tao Wenquan
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
Pool boiling outside a horizontal enhanced tube with the new refrigerant R134a was
experimentally investigated. The correlation amon g the heat transfer coefficient, heat
flux and saturation pressure was obtained by using the multi-variables linear least-square
method. The enhancement characteristics of heat transfer coefficient of the enhanced tube
against smooth tube we re also analyzed. The results showed that for the enhanced tube
studied the boiling heat transfer coefficients of R134a is lower than that of R22.
Keywords: substitute
refrigerant, boiling heat transfer, heat transfer enhancement
Numerical
Simulation and Analysis on £Ç-£Í Refrigerator Working in the
Liquid Helium Temperature Region
He Yaling, Zhao Jiawei, Xu Mingyao,Chen Zhongqi
(Xi'an Jiaotong University, 710049, Xi'an)
Zhang Liang
(Cryogenic Laboratory, Academic Sinica China)
[Return]
Abstract:
Numerical analysis on a two-stage C-M refriger at or with magnetic regenerator
material(Er3Ni and ErNi2) working in liquid h
elium temperature region was carried out. The effects of variable properties of real gas
and material, characteristic of valve, coupled heat transfer of regener ator, mutual
influence of first and second stage, and so on, were considered in the model. Numerical
simulation results are in good agreement with those of expe rimental study.
Keywords:
refrigerator, refrigeration cycle, numerical simulation
Flow- Visualization Study on Secondary Flow in Turbine Cascade under Large Negative
Incidence
Chang Jianzhong, Feng Zhenping, Shen Zuda
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract: In
this paper, oil-film technique is applied to the study of the secondary flow and vortex
structure in turbine cascade with the va rious pitch and inlet pressure condition under
large negative incidence. The obt ained results are shown with photographs and the
structures of flow fields are analyzed in detail. The flow-visualization study reveals the
development of se c ondary flow in cascade passage, and is helpful to understand the
mechanism of lo ss production of secondary flow.
Keywords: secondary flow,
flow-visualization, pitch, pressure, incidence
Research
on Theories of Reliability Design of Straight Side Combined Frame's Tension Rod
Zhao Shengdun, Han Huilan, Wang Jiezhi
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
On the basis of analysing problem of traditional design method of straight side combined
frame's tension rod, necessity that the tension rod is designed with reliability theories
is put forward.Active stress and failure mechanism are thoroughly analysed. Expressions of
range , amplitude, mean and cyclic characteristics of stress acting on the tenision rod in
the course of operation are first proposed,thus establishing a complete theory of
reliability design for the tension rod, seemingly first time in the literature
Keywords: straight
side press, frame, tension rod, mechanical reliability
Influences
of Different Fluid Flow Models on Calculated Results of Mold Filling
Yang Bingjian, Cai Linning, Su Junyi
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
Based upon the calculation of flu id flow with the commercial software PHOENICS, the free
surface during the mold filling is tracked to solve the conserved scalar equation by using
van Leer scheme.The different filling processes in cavities are simulated with several
fluid flow models such as laminar assumption,K- urbulent model and algebraic stress model,
and the influences of different models on the computed results are presented. It is
demonstrated that each fluid flow model has its own applicaiton limitation. The choice
principles of models are suggested for the mold filling according to the order magnitude
of Reynolds number and the geometric shape of the cavity
Keywords: fluid
flow model, mold filling, numerical simulation, PHOENICS
Research
on the Distributed Concurrent Cooperative Solving Model of CAIP
Peng Junsong, Bai ZuoLin, Zhao Rujia
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
STRIPS planning system grammar pattern and graph theory are used in discussing the
knowledge-based world model of the general inspection planning, the abstract planning
hierarchy and the relevant task decomposition algorithm to build the distributed
concurrent cooperative solving model of IDPIP, the integrated developing platform for the
intelligent inspectio n planning based on distributed concurrent problem solving
Keywords:
inspection planning, distributed concurrent cooperative solving, task decomposition
A
New Method for Machining Curved
Surface of Piston
Zhou Limin, Zhao Wanhua, Hui Yanbo, Lu Bingheng
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstrac:
A new method for machining the curved surf ace of piston is presented. Using the vibration
technology and the special CNC, a practical machining tool for machining piston is
developed. The result of test ing and experiment has proved that the system has high
efficiency£¬ high preci si on and a certain flexibility.
Keywords: piston,
curved surface, machining
Experimental
Studies on the Fatigue Strength of Concrete under the Complex Stress State
Yu Maohong, Zhao Junhai
(Xi'an Jiaotong University, 710049, Xi'an)
Zheng Shujun
(Northwestern Research Institute of Hydraulic and Power Engineering)
Dong Wenshan, Zhang Chunyan, Zhang Ning
(Xi¡äan Aeroengine Institute)
[Return]
Abstract:
The fatigue strength of a thin concrete tu be under the complex stress states is studied.
Based on the twin shear strength theory and three series of tension-torsion experiments of
the concrete tube, an empirical experession is proposed which can predict the multiaxial
fatigue streng th of concrete tube under stress state.
Keywords: multi
axial fatigue, twin shear strength theory, concrete
Numerical
Approach on the Strain Softening Behaviour of So ft Rock
Liao Hongjian, Ning Chunming, Yu Maohong
(Xi'an Jiaotong University, 710049, Xi'an)
Masaru Akaishi
(Tokai University, Japan)
Zhao Shude
(Xi'an University of Architecture & Technology)
[Return]
Abstract: This
paper is concerned with a new concept of mo delling the strain softening behaviour of
diatomaceous soft rocks based on the laboratory investigation. An approximate solution was
described for a stress-strain-time relation taking account of strain softening phenomenon.
The treatment of the post peak behaviour in the calculation is discussed and comparisons
of th e experimental observations of normally consolidated and overconsolidated specim ens
with numerically simulated results are given. It is shown that the strain ra te effect and
strain softening behaviours are controlled by the time-dependent stress strain relation.
Keywords: soft rock, strain
softening, strain rate, stress-strain-time relationship
Study
on Unsaturated Polyester/Polyurethane Two-Component Coating
Zhang Xinsheng, Lu Fengji, Ding Ailin
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
This paper presents the preparation of two-comp onent coating which is synthesized by
unsaturated polyester resin end-blocked b y hydroxy and prepolyurethane end-blocked by
isocyanate. It is a fine decorativ e coating with high lustre, high fullness and can cure
at ambient temperature. Molecule structure of unsaturated polyester is designed to control
the whole prop erties of the coating. The step reation between hydroxy and isocyanate is
not re tarded by oxygen in the air, and the coating has good surface hardness. The
cross-linking system is also discussed.
Keywords: unsaturated
polyester, polyurethane, cross-link, synthesis, coating
The
ComputerAided Test of the Refrigeration Compressor Internal Performance
Wang Yi, Yang Zhenkun, Han Yali, Liu Dajiang
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Abstract:
This paper introduces the basic structure of a refrige ration compressor internal
performance automatic test system. It is composed of transducersกข transmitters and microcomputer. Its hardware and software function are
described. The microcomputer system calibration and error analysis are stud ied. Finally,
a testing result is given.
Keywords: refrigeration
compressor, test system, microcomputer, transmitter, system calibration
A
Computer Image Processing System for Infrared Thermovision
Zhao Mingtao, Zhang Guangming, Hou Chenggang,Wang Yuwen
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]
Development
of Vertical down Basic Electrode
Used in Pipewelding
Chen Ziqiang, Shen Fenggang, Pan XideXue Jin
(Xi'an Jiaotong University, 710049, Xi'an)
[Return]