Load modling and analysis of wind turbine under consideringthe space coordinate transformation

Based on coordinate transformation and mechanical analysis, load transformation between blade root and rotor coordinate system for wind turbine is derived.And an analysis model closer to actual working condition is established.Taking a 5 MW wind turbine as analysis object, analyzing results of the new model, traditional simplified model and GH Bladed model are compared, and results are good enough to validate this new model has higher reliability and accuracy.In addition, based on analyzing to load component, through access to instance data of each factor in process of coordinate transformation, the impact of each factor can be accurately analyzed, which is of great significance to control and reduce load.     

Structual Dynamic Characteristics Analysis and Improvement for Two-way Branch Exhaust Pipe Shield

The two-way branch exhaust pipe shield is the main source of surface radiate noise of a vehicle's engine.(Using) the finite element analysis software ANSYS,a finite element model of the shield is established,and then the(modal) analysis is done theoretically with this model,the result is consistent with the experiment.The result shows that this finite element model can be used for the next structual dynamic characteristics analysis.With this model,the relationship of structural parameter,structural style of the shield and the corresponding vibrative modal is analyzed.The(optimal) improved measures are adopted which is based on the practical structure of the shield.The analysis of the(improved) structure shows that the increase of natural vibration frequency is visible,the vibration noise of the shield is suppressed distinctly.     

Quantitative analysis of photoacoustic spectroscopy detection for dissolvedgas in transformer oil based on least squares regression

Current solutions solve each component's gas concentration by multi equation inverse calculation, which has disadvantage of introducing parameter errors like noise, constant pool, etc. Based on the photoacoustic spectroscopy detection principle, a novel method for photoacoustic spectroscopy quantitative analysis is proposed using least square regression, and a quantitative analysis model is constructed. Using this method in inverse calculation of the gas concentration can avoid introducing parameter errors. The analysis model is verified by the experiment on the acetylene and methane dissolved in the transformer oil.     

THE REAL RESISTIVE MODEL FOR FREQUENCY -DOMAIN ANALYSIS

A new model for frequency - domain analysis - the real resistive model which is based on Complex Network Theory is proposed in this paper. The network equations formed with the new model without contain complex numbers because there are only sources and resirtive elements in the model. A CAA algorithm for frequency analysis by using the new model is also given. It is shown that the trouble with the complex operation in the traditional algorithm has been avoided. The algorithm presented in this paper is simple and convenient,hence it is easy to popularize.     

A mathematical model on the pulverized coal blending optimization for blast furnace injection based on principal component analysis

A mathematical model of coal blending optimization for blast furnace injection is proposed. Because Chinese current blast furnaces blend pulverized coal by simple mix and traditional lab blending optimization needs plenty of work for the larger number of characteristics of pulverized coal. The new model is based on the principal component analysis indexes P1, P2 and P3 combined with the proximate analysis and elementary analysis of pulverized coal. P1, P2 and P3 are obtained from principal component analysis of the injection characteristic of pulverized coal determined by lab experiment. This model is proved to be effective on both lab experiment coal blending and actual production of BF.     

Constitute of Meteorological Data in Building Energy Analysis

Building energy analysis needs representative yearly meteorological data,the data could be selected from the past years' data according to specific regulation,it can also be produced from the meteorological math model which was built with the past data. A comparison is made between F testing method and AIC criterion method, which leads a result that the F testing method is reasonable. Mixed regression model of thirteen dimensions is established using F testing stepwise method. Test is conducted on independence and distribution of model residuals, and the result shows that the model is successful and more information can be provided for establishing model with dimension number increased. Using the above established model future meteorological data of building energy analysis can be predicted.     

河北省板栗产量预报技术的研究

本文总结了一种以预报模式为主,结合科学考察、专家经验的统计预报技术.其分析预报思路是:自身分析—相关分析—析因分析—系统分析.     

Establishment and analysis of dynamic mathematical model for coal gasifier

Based on the analysis of flowing combustion, gasification reaction, and lumped parameter, a three region model is established to predict the temperature and gas components of Texaco coal gasifier. Using mass balance and energy balance equations to each zone, the model takes account of gas solid two phase flow, coal pyrolysis, radiation heat transfer, and heterogeneous and homogeneous kinetic chemical reactions. Based on the model, a program is developed for dynamic and static simulation. After parameterization and simulation analysis, some important trends and conclusions are attained. Because the model can accurately predict the temperature and gas components in jet region, it has widespread engineering application value.     

Vendor-managed Inventory Model with Time-limited Free Back- orders

Based on the VMI model with completely backlogging and without backlogging, the authors develop a new VMI model with partial backlogging and time-limited free back-orders, including a single vendor and multiple buyers. This model modifies the backlogging cost proposed by some documents, and takes account of the deterioration cost in the analysis of the total inventory cost. A numerical example and sensitivity analysis are presented to illustrate the model. The theoretical evidence is provided for VMI system to make management decision.     

非独立试验数据的一般线性混合模型分析

传统方差分析模型的假设条件之一是试验数据相互独立,实际的试验数据未必能满足其条件,这使方差分析的应用范围和分析的效果受到限制。近年来,一般线性混合模型得到发展,为分析非独立试验数据提供了新途径。本文讨论了一般线性混合模型分析非独立试验数据的方法及其在SAS软件的实现,对小麦品比和玉米灌溉2个不同试验的非独立数据进行了一般线性混合模型与方差分析模型的对比分析。结果表明,与传统方差分析法相比,一般线性混合模型数据拟合效果好,在小麦品比试验使小麦品系效应比较的平均标准误降低18.4%,平均分析相对效率为1.5,而在玉米灌溉试验使灌溉效应比较和品种×灌溉交互效应比较的平均标准误降低9.1%￣10.8%,平均分析相对效率均约为1.2。因此,对非独立试验数据,一般线性混合模型分析的准确性和效率要比传统方差分析模型高。     

Study on Cusp Catastrophe Mutation of Slope Destability

A complete theoretical model for slope destabilizing mutation has been set up by studying the geomechanical model and the influences of all circumstantial factors on slope stability,and by applying nonlinear theory.This paper analyzed the influence of controlled variables in the mutation model on the slope in causing slow or fast creeping.As the limit equilibrium stability analysis method of rigid bodies has some defects in slope stability assessment,the new theory of rigidity destabilization is helpful in forming criteria for judging slope creep destabilization.This analysis explains well the underlying causes of creeping slope destabilization and proves the feasibility of studying slope creep with a mutation model.     

Research on the Minimum Number of Teeth of Double Involute Gear

To meet the needs of the multi-function and the multi-use of the modern tall buildings, the megastructure systems have been gradually emerged and used in tall buildings in many countries. In this paper, the analytical model and relative analysis method due to vertical seismic action of the megastructure are presented, including the spectrum and time-history analysis. The results of the calculation of an example show that the vertical seismic action on megastructure is remarkable. It reminds us that the vertical seismic action on megastructures can't be neglected in the design of this kind of structures. Furthermore, it is pointed out that the "story model" is not suitable to megastructures in dynamic analysis.     

Uncertainty Analysis of Long-term Deformation for Prestressed Concrete Beam

Owing to the randomness of shrinkage and creep of concrete, random analysis method should be adopted to give a reasonable result with probabilistic guarantee. Stochastic variables for long-term analysis with GL2000 model about creep and shrinkage of concrete were presented. Combining Monte Carlo sampling with the response surface method, the stochastic analysis model was performed which is on time-variant deflection of prestressed concrete bridge. The long-term deflection of a prestressed concrete bridge was analyzed by this model. Sensitivity analysis and parametric study were carried out. And the uncertainty of creep model, elastic modulus of concrete, magnitude of sustained load, and prestress forces are the most important factors for long-term deflection. Furthermore, controlling accuracy of prestress forces and delaying the loading time are helpful to inhibit long-term deflection.     

Torsional Vibration Simulation Analysis of Drilling String and Rock Bit

In this paper,the method of establishing the torsional vibration model of drilling string and rock bit and the process of simulation analysis are introduced.The interaction between bit and rock and elastic deformation of drilling string in the process of petroleum drilling which caused the torsional vibration of the drilling string and rock bit is main considered in establishing the model.The torsional model is solved by difference method.Based on the models,the simulation analysis software of drilling string and rock bit is designed,and simulation calculation and analysis of the tortional vibration of drilling string and rock bit under different conditions are computed,and the dynamic behavior and kinetics regularity of drilling string and rock bit in drilling are obtained.     

Dynamic FEM Analysis of Automobile and Software Development

In this article, modal analysis technology about dynamic analysis was studied. Free interface model comprehensive method was used to dynamic analysis and design of automobile structure based on theory background of model analysis, test technology conditions, data reliability and precision. In order to test the efficient and possibility of the method, main vibration features about space double layer has been calculated based on this method, comparing this with the precise solution of finite element method, the result shows that this method is suitable not only for simple interfaces between components but also for high reductive interfaces. In addition, the method also has high comprehensive precision. Furthermore it creates conditions to dynamic analysis in automobile structures.     

Sky luminance distribution model by ant colony systems

The sky luminance distribution model is developed by information analysis methods with ant colony system. A new arithmetic is given to solve complex optimization heuristic algorithm. The coefficient values of sky luminance distribution function are obtained by optimization analysis with ant colony system and on which a set of practical software is developed. It can provide an intuitive and easy calculation. The model has higher precision, which can provide valuable results on high precision and standard daylighting design.     

多个数值预报产品对山西3次强降水过程预报性能的对比分析

为更好地释用数值模式的预报产品,采用客观分析和ETS评分方法,运用T639-thin模式、ECMWF-thin模式、Japan_thin模式及NECP模式对2014年7月发生在山西的3次降水过程的预报性能进行了效果检验和对比分析。分析结果表明：4家模式对欧亚大陆中高纬环流形式以及地面系统的调整和演变均有较强的预报能力;4家数值模式预报产品基本能把握雨带的走向,但对强降水过程中降水强度的模拟与实况相比偏差较大,而且对强降水中心的预报稳定性也较差;对于ETS评分,NECP模式的评分在3次过程中均较高,并且不同数值模式的24 h时效预报效果要优于其他预报时效。总体来看,对于环流形式的演变,EC模式模拟效果是最好的,其次是NECP模式,T639模式和日本模式次之;对于降水量级以及落区的预报,NECP模式预报较准确,具有较高的参考价值,其次是EC模式,而T639模式和日本模式预报的稳定性较差。     

毛竹林叶片磷和钾含量的不同尺度光谱响应研究

研究不同尺度光谱对毛竹林叶片磷和钾含量的响应机制,为实时掌握毛竹林生长状况和营养水平有理论意义和实践指导价值。以毛竹林叶片与冠层2个尺度的原始光谱为数据源,通过一阶微分光谱等光谱变换,采用回归统计分析构建不同尺度磷素和钾素含量与敏感波段的光谱估算模型,并对其稳定性和预测性进行精度评价。结果表明：叶片光谱分析中以磷含量一阶微分光谱为变量的线性回归方程模型拟合精度高达74.90%,且在建立专一性较高的磷素含量估算模型上更有优势;冠层光谱分析中以钾含量一阶微分光谱为变量的线性方程模型拟合精度高达78.71%,且在建立专一性较高的钾素含量估算模型上更有优势;同时,一阶微分光谱可降低空间异质性以提高光谱估算模型反演精度。     

Model Analysis of Tower Crane Structure Based on ANSYS

In this paper,a complete dynamic model of the tower crane is set up by the finite element software ANSYS and then the QTZ25 tower crane model is calculated.Through comparing the results,the feasibility of this method is proven.This method is a new approach to fast and precise analysis on dynamical model of tower crane structure.     

Power model and tarepower characteristic of CNC machine tool feed system

A power model of a CNC machine tool feed system is proposed based on analyzing the power characteristic of each component in the CNC machine tool feed system. And the tarepower characteristic and its dominant affecting factors are analyzed by using the power model. The analysis results show that the tarepower of feed system is a monotone increasing quadratic function in term of the feed speed. Meanwhile, the feed speed and load mass both affect tarepower, but the influence of load mass is minuteness. Some experiments are conducted on a 3-axis CNC milling and the experimental results justify the theoretical analysis.