Perturbation Analysis of Complex Modes for Vibration System with Viscous Damping and Its Application

The sensitivity characteristics of the undamped natural frequencies and complex mode shapes of vibration system with the non-proportional viscous damping with respect to structural mass, stiffness and damping modifications are analyzed in this paper using the matrix perturbation of complex modes. The general principles for the selectivity of the design and the most sensitive positions of the structural perturbation modifications are shown thereby. This is of importance to a great computational savings in the dynamic characteristic improvement of large or complex structures. By the dynamic characteristic sensitivity analysis of a test device type RDT-1,the optimal structural design for its especial requirement of dynamic characteristics is obtained easily and the principles presented in this paper are confirmed by the numerical results of perturbation analysis.     

A NEW METHOD FOR DESIGN OF PSS PARAMETERS

The eigenvalue sensitivity methods is very useful not only in analysis of electric power system stability but also in design of the controllers. In this paper a new optimal method is proposed to design the parameters of PSS. Using this method the PSS is designed for a single machine-infinite bus system, and the results of digital simulation show that this method is very effective and useful.     

A Synchro-Solution Method for Generalized Eigenproblem and its Application in Parameter Sensitivity Analysis

A high efficient synchro-solution method for generalized eigenproblem has beenproposed ,it has also been demonstrated that how the method can be used in vibration parameter sen-sitivity analysis of the higher order non-self-adjoint vibration system such as rotor-journal bearing system.     

Analytic Method for the Free Vibration of Plane Frame Structure

The analytic method for the free vibration of plane frame structure is presented. It is achieved by transforming the general eigenvalue problem of natural frequency and vibration mode of continuously distributed property system into typical boundary value problem of ordinary differential equation (ODE). A series of ODE, corresponding to the general eigenvalue problem, is formed, and then is solved by an general ordinary differential equation solver-COLSYS. Each component of a frame structure is regarded as an element in the analytic method. This makes it more efficient than that of finite element method which needs to increase elements to get the value of high-class natural frequency and vibration mode accurately. Some applications of the method show that it can solve the free bending vibration of plane-frame structure with various types of displacement constraint. The result indicates that this method is precise and efficient.     

Modal Shape Analysis Methods of Machine Structure

The iterative Lanczos-reduce method for sensitivity analysis, the Guyan condensed method and the iterative synchronous vector methods in finite element modal are studied in order to solve the dynamic characteristic of complicated machine system. The primary reasons influenced on calculation precision are pointed out. The principia of master freedom for Guyan condensed method are put forward. The calculation precision of three methods is compared with the same standard finite element model. The iterative Lanczos-reduce method for sensitivity analysis is proved to be optimum analysis and the eigenvalue of arm in work device of hydraulic excavator in finite element model is solved with iterative Lanczos-reduce method for sensitivity analysis. The theory basis is provided for reasonable choose to solve the dynamic of complicated machine structure.     

An Analysis of the Bearing Loads of the Domestic 200MW Turbine Generator Set

The distribution of tre bearing loads of the domestic 200MW turbine generator set, which depends on their relative positions,have been studied under different supporting conditions. An iterative method has been developed to calculate all of the bearing loads, which takes the structural static indetermination and nonlinearities of the oil film forces into consideration. Variations of the bearing relative positions and their influence on the stability of the rotor-bearing system, have also been discussed.     

Sensitivity analysis of a motorcycle frame using the Monte Carlo method

Sensitivity analysis of motorcycle frames is useful for improving the design success rate. Based on sensitivity analysis theory and using the Monte Carlo and numerical simulation methods, a new 250 type integral motorcycle model was built and dynamic sensitivity analysis conducted. Sensitive design parameters that have great influence on frame vibration were discovered. By modifying the values of sensitive design parameters, the vibration of some measuring points was reduced. This reduction shows that the sensitivity analysis method is reliable and practical, and it can be used in sensitivity analyses of other complicated structures.     

Operational Deflection Shape Analysis of Large Scale Electromechanical System

Operational Deflection Shapes of large scale electromechanical system can be ex-tracted directly from multipoints response of the operating system by using of the modal shape analy-sis method. Thev can be used for engineers evaluating the practical dynamic beavior of the largescale elecltromechanical system,checking the existence of local reso,iance of the Stibsystem. and in-dentifying the wcakened positions of the rigidity of structure, In this paper the method of measuringand extracting the operational deflection shal1e of the electromecha nical system is given and theavailability of operational deflection shape is proved by analyzing the actual vibration of a large ex-haust fan system as an example.     

Assessment of uncertainty and sensitivity analyses for ORYZA model under different ranges of parameter variation

We explore the effects of different ranges of parameter variation (RPV) on sensitivity and uncertainty analyses for ORYZA_V3 model. In this study, a latin hypercube sampling (LHS) technique is used to generate parameter sample sets, and a regression-based method is employed for the sensitivity analysis on 16 crop parameters. Then, a top-down concordance coefficient (TDCC) is calculated to assess the stability of parameter sensitivity rankings across diverse RPV. Furthermore, coefficients of variation (CV) and 90% confidence intervals (90CI) of daily model outputs are analyzed by considering uncertainty in observations. We find that the increasing RPV multiplies the CV of daily model outputs, whereas the RPV has no effect on the CV’s change rule over time. The 90CI of model outputs include most of the observations when the RPV is more than ±30% perturbation. The standardized regression coefficient (SRC) of some parameters are obviously minified when the RPV is ±5% or ±50% perturbation. The results highlights the importance of RPV selection in the sensitivity and uncertainty analysis of crop model, and ±30% perturbation was suggested when the RPV cannot be specifically obtained.     

转基因玉米CM8101特异性定性PCR检测方法

旨在为转基因安全监管提供技术支撑,本研究建立了转基因玉米CM8101定性检测方法。根据CM8101转基因玉米插入序列信息,于3′端侧翼序列处设计PCR引物。通过扩增体系优化、特异性测试、灵敏度测试、稳定性测试等技术参数的测试建立了转基因玉米CM8101定性检测方法。结果表明:本特异性检测方法各项参数符合相关转基因分子检测标准的要求,具有良好的品系特异性,方法检测灵敏度可达0.1%。CM8101是中国自主研发的具有产业化应用前景的转基因玉米新品系,本方法为品系和其衍生产品的鉴定提供技术手段。     

Dynamic characteristics research of gear coupling rotor system in gas turbine

Taking the sliding bearing into account, the lateral vibration analysis models of two single rotor were built respectively using the transfer matrix method. The transmission matrix of herringbone gear coupled unit is derived. Using whole transfer matrix method, the lateral torsional coupling analysis model of herringbone gear rotor system is set up, and the vibration characteristics of gear rotor bearing system in gas turbine is analyzed. Through numerical calculation and anlysis, the eigenvalue of gear rotor system, the Logarithmic decrement and the critical speed are obtained. The result shows that the working speed of this gear rotor bearing system is far away from the critical speed, therefore the system is stable and safe.     

基于GIS和地统计学的土壤养分空间变异特征研究 ————以新疆农七师125团为例

基于地理信息系统(GIS)和地统计学，以地理信息系统软件ArcGIS为平台，采用Geostatisical Analyst地统计分析模块中的Kriging插值方法研究了新疆农七师125团土壤养分的空间变异性。应用GIS能够将系统变量的属性数据同地理数据相结合，使大区域范围内进行地统计学分析变得较为方便，研究结果表明，全氮、有机质、速效磷、速效钾均具有中等的空间相关性，但变异尺度不同。分析中还发现Kriging插值模型的选择及Crossin—ValNation交叉验证的检验与系数修正均影响分析工作的结果精度。     

The Application of Extrapolation of FEM to the Eigen Value Problems of Waveguide

On the basis of the method of linear finite element and taking the advantage of the theory of finite element extrapolation,the paper discusses the method for calculating the eigenvalue of waveguide.The results show the method is simple and has higher accuracy.     

不同大小辽东栎种子的脱水敏感性

以采自宁夏六盘山区的辽东栎种子为材料,在缓慢脱水和快速脱水条件下,研究了不同大小种子的脱水耐性。结果表明,轻度脱水对种子萌发具有促进作用,但种子萌发率随着脱水时间的延长和含水量的继续减少而显著降低;不论是缓慢脱水还是快速脱水,不同大小种子的萌发速率和萌发指数均随脱水时间的延长持续减小或波动性减小,且都在缓慢脱水36h后和快速脱水8h后显著降低;活力指数在缓慢脱水72h和快速脱水24h前的各脱水阶段均不同程度地增大,但在缓慢脱水120h和快速脱水48h后显著减小。大种子含水量和萌发率在脱水过程中始终显著高于小种子;尽管不同大小种子间的萌发率仅在脱水后期差异显著,但大种子萌发速率、萌发指数和活力指数均显著大于小种子,且在脱水处理后期所有萌发参数在不同大小种子间均差异显著。     

Simulation Analysis on Decreasing Vibration of Motorcycle Engine Suspension System

With the development of high-speed and high-power, the motorcycle vibration from engine become one of the major factors affecting the performances of motorcycle. Elastic suspension structure is adopted between the engine and frame for the vibration during the process of designing a certain type of motorcycle with 200 cc engine in some enterprise.Through optimization of the suspension system performance parameters, inherent frequency of suspension system keeping away from the activated frequency of engine in common use is essential. Isolation performance is improved and the vibration is solved. As a result, the comfort is improved.     

THE FREQUENCY DOMAIN DISCRIMINATIONS OF SEVERAL VIBRATIONS ON THE TURBOGENERATOR

The frequency spectrum analyses of several vibration on No. 4 Unit in a power plant are made and the experience of the future failure diagnosis on turbogenerator is collected in this paper.     

Testing and modal analysis on multi stage planetarygearbox housing of shield tunnelling machine

The finite element model is developed for the multi stage planetary gearbox housing in shield tunnelling machine (STM), and the the eigenvalue problem is solved by using block Lanczos method, and then the low order natural frequencies and corresponding modes are extracted. Based on the theory of experimental modal analysis, the modal testing is made for the gearbox housing by pulse excitation method. The least squares complex frequency domain (LSCF) estimation method is used to analyze the modal data, and the natural characteristics of housing is obtained. According to the modal assurance criterion (MAC), the experimental modal parameters are validated. Modal analysis shows that the experimental data is coincided with analytical results, which indicates the accuracy of the theoretical model and testing method. The coupling sympathetic vibration is disappearing between the gears train and housing, the local vibration is large at the high speed side of gearbox housing, and the torsional mode is outstanding under operating condition. The research results provide theoretical basis and experimental support for the structural optimization of the gearbox of STM.     

Sensitivity analysis for a complex crop model applied to Durum wheat in the Mediterranean

Complex crop models with large parameter sets and high temporal resolution need a parsimonious screening method to identify the most important parameters for the genotype by environment interaction in a specific context. Morris’ method of sensitivity analysis, changing parameters “One-at-a-Time” (OAT) was applied to yield formation of Durum wheat (DW) in two different Mediterranean sites (Italy, Tunisia) and rainfall regimes (average, ?25%). 46 crop and site-specific parameters were screened and ranked for their sensitivity, and our objective was also to determine the minimum requirements for the parameter sampling strategy. The number of levels and trajectories for sampling the multi-dimensional parameter space were varied between 4 and 8 and 4 and 10, respectively.Key results are that (1) Parameters for development and early light interception ranked higher than those for photosynthesis and assimilate partitioning, of which the latter also showed some redundancy. (2) Parameters referring to transpiration and water stress response are ranked in 11th position or greater; however, their rank differed greatly between sites in response to natural and imposed water shortage. (3) Ranking for sensitivity is stable within each site, but differs among sites; the choices of level and trajectory number have a similar impact on the ranking stability. Finally, first order sensitivity rank (strength, μ*) is similar to 2nd order sensitivity (spread, σ), which indicates that parameters with a high effect on output show also high interaction with other parameters or non-linearities. Overall, Morris’ method proves an effective and reliable tool to identify key phenotypic crop and management parameters and to select traits for optimizing yield in different environments.     

A TIME AND FREQUENCY DOMAIN METHOD FOR IDENTIFICATION OF PHYSICAL PARAMETERS

In this paper, a-method using the complex modal theory to identify physical parameters of system with viscous damping is discussed. A procedure is present to calculate the mass, clamping, and stiffness matrices from the measured data in time and frequency domains. The double least squares approach is used to identify modal parameters. In identification of physical parameters, the data of different measured point is used in calculation for more accurate results.     

热风干燥智能控制系统的设计

根据热风干燥工艺特性,借助自研开发的热风干燥实验台,基于PLC设计了热风干燥智能控制系统。针对热风干燥实验台温度非线性、大滞后和惯性大的特点,采用模糊—PI控制器,保证了温度控制精度和稳定性。该控制系统实现了温度、湿度、风速和干燥时间的分阶段设置和显示,趋势曲线显示和历史数据下载功能。