A Method of Analyzing the Parameter Sensitivity of Large Rotor Systems and Its Application

Based upon the eigenvalue sensitivity theory of non-self-adjoit system and the component mode synthesis method,a new technique is developed to analyze the eigenvalue sensitivity to variation of parameters of large rotor-bearing system. As an application, the influence of the journal bearing parameters on the stability of a large domestic turbine-generator set is analyzed and discussed.     

Analysis on the Quasi Monte-Carlo Method and its Application in the Slope Reliability

The critical reliability slip surface with minimum value of reliability index is difficult to be obtained by the Monte-Carlo method. The simplified Bishop method was adopted to calculate the factor of safety for given circular slip surface thereby defining the performance function in reliability analysis. Six variance values of random variables were designed and four sample ranges were assumed. A quasi-Monte Carlo method was defined with fow samples. One hundred and thirty-two potential slip surfaces were randomly generated. The reliability indexes regarding those slip surfaces were calculated by Monte-Carlo method and quasi-Monte Carlo method, respectively. The comparative results show that in the case of one random variable, the reliability index from Monte Carlo method is found to be linear with that from quasi-Monte Carlo method. In the similar conditions, the wider the sample range, the smaller the tangent value of line, and Vice versa. In addition, the bigger the sample number, the bigger the tangent value of line. The Quasi-Monte Carlo method is approved to be practicable for the determination of critical reliability slip surface for homogeneous slope.     

Error Analysis between Relative Motion Solving Method and Absolute Displacement Direct Solving Method

Under multi-support earthquake excitation, the damping is proportional to the relative velocity in relative motion method, While the damping is proportional to the absolute velocity in method of direct solving absolute displacement, and the damping assuming difference may cause the calculation errors on structural responses. The structural response errors of the dynamic component of power spectral density between the two solving methods are derived by random vibration theoretical analysis in Rayleigh damping model, which include damping ratio and the ratio between excitation frequency and fundamental frequency of the structures. Based on probability theory, the variation errors of dynamic component response between the two solving methods are also derived by theoretical analysis, and some numerical examples are provided to verify the error analysis. At last, it is pointed out that the calculation errors between the two solving methods decrease with damping ratio, and it is negligible when the damping ratio of structure is less than 5%.     

Coupled Thermo-Elastic Contact Finite Element Method and It''s Application in Gearing

A new finite element method is presented in this paper to analyze the thermo- elastic contact problem with heat input on meshing tooth faces. The computational model of meshing gear has been established and the frictional heat input on meshing tooth faces is estimated. In addition, 2-D finite element analysis program for this kind of problem is listed. The test and practical examples are given to show the validity and versatility of this method.     

A New Method for First-Order Analysis of Thin-Wall Member

Based on the calculation procedure of dynamic coordinate method, the examples in this paper prove, that the first-order stress of thin-wall member is easily calculated with the new method and that a new method of first-order analysis is easily comprehended.     

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.     

宁南山区林果产业发展现状 存在问题及对策

针对宁南山区林果产业发展现状,分析了当前存在的问题。提出通过转变观念、新品种引进、示范区带动、产业带建设和水资源结合、规范技术管理、提供中介服务、提高果品深加工处理水平、制定优惠政策等措施,进一步促进宁南山区林果产业有序健康发展。     

Conflict Analysis Method in Water Resources Control and Distribution on Heihe River

Coordinating distribution of water resources of a river across more than one administrative regions is a critic issue connected with rational resource development and environment conservation among different administrative bodies and finally with the resolving problems about water resources distribution among them . By the quantitative analysis and based on META-game theory, this paper has analyzed the conflicts over water distribution among several administrative bodies within the Heihe river basin, and established mathematic models to obtain reasonable recommendation that might benefit and be acceptable to each part in the conflicts in order to end the long time dispute over water distribution in these regions.     

Application of Symmetric Galerkin Boundary Element Method in Limit Analysis of Plane Problems

Based on Melan's theorem, the symmetric Galerkin boundary element method (SGBEM) is used to discretize two dimensional structures and a computational formulation of structural limit analysis is established. The self equilibrium stress field is constructed by linear combination of several basic vectors, which are the stress differences between different iteration steps at the same increment using the traditional elastoplastic incremental method. Then the complex method is used to solve the nonlinear programming directly, so that the lower bound load multiplier of two dimensional structures is obtained. The validation of the present method has been confirmed by some numerical examples.     

同异分析法在粒用高粱杂交种评价中的应用

采用同异分析法对吉林省农业科学院2018-2020年登记的11个高粱杂交种的产量、生育期、株高、穗长、穗粒重和千粒重等11个主要性状进行了综合分析和评价,按照联系度值排先后顺序,即吉杂225、吉杂235、吉杂236、吉杂227、吉杂224、吉杂229、吉杂228、吉杂157、吉杂149、吉杂233和吉杂237。结果表明,同异分析法能够综合、客观地评价供试杂交种,可为育种者提供更多的信息来改良品种,是开展育种工作的良好方法。     

Boundaty Element Method for Analysis of Thick Plates on Two- Parameter Elastic Foundations

This paper discusses the Reissner's plates on elastic foundation.The elastic foundation is considered as two- paramerer and its effect to thick plates are taken into account by a set of govering differential equations. According to the foundamental solutions for bending problem on two- parameter foundation derived, three boundary integral equations denoted by generalized displacement functions are established. This method is suitable to solve the bending problem of thin or thick plates on two- parameter foundation with arbitary boundary condition, arbitary shape and arbitary load conditions     

Envelope Analysis Technique and Its Application in the Gear Failure Vibration Diagnosis

The gear failure vibration diagnosiS in a gearbox is of great importance in manyfields.Through theoretical analysis and engineering application,two methods of gear vibration en-velope analysis technique are discussed in this paper.Zoom Hilbert transform en velope and zcomnarrow-band en velope are formed by applying zoom technique to Hilbert transform demodulationand narrow-band demodulation in order to increase the frequency resolution of demodulation spec-trum.     

Boundary Element Method of Material Parameter Identification in 3-D Infinite Problem

A 3 D boundary element method and dual boundary control technique of material parameter identification were proposed in this paper. The infinite boundary element was used for infinite problem in geomechanics.The computational result shows the validity of the proposed method.     

超临界CO_2萃取法与水蒸气蒸馏法提取月见草油成分的GC-MS分析

采用超临界CO2萃取法和水蒸气蒸馏法提取月见草油,并应用GC-MS对该两种方法提取的月见草油成分进行对比分析。结果表明:两种方法提取的月见草油化学成分仅有1种相同,为2,4-癸二烯醛;水蒸气蒸馏法提取鉴定的20种成分占挥发油总量的98.56%,其中有19种属脂肪酸类,占98.33%,以棕榈酸乙酯含量最高,占41.56%;超临界CO2萃取法提取鉴定的18种化合物,占挥发油总成分的91.08%,其包含醇、醛、烯、萜、烷烃及不饱和脂肪酸等多个种类,以β-谷甾醇的含量最高,达52.58%。     

Nonlinear Analysis Technique of Refined Plastic-hinge Method for Steel Frame Structures

The refined plastic-hinge method is one of the simplified advanced analysis methods. The second order effects of the whole structure and its members, geometric imperfections and residual stress as well as the feature of semi-rigid connections can be taken into account in this method. The refined plastic-hinge method can be used in advanced analysis and design of planar steel frames, while its use in the advanced analysis of space frames needs to be developed. The technique associated with the dealing of different inelastic factors in advanced analysis of both the planar and space steel frames with practical refined plastic-hinge method and the available way to extend planar frame analysis to space frame analysis are reviewed in detail. The problems of the refined plastic-hinge method for advanced analysis are discussed in this paper.     

Application of Revised BP -NN Method to Landslide Stability Analysis in the Three Gorges Area

Using the revised BP-NN,this paper presented the neural network method for landslide stability analysis in the Three Gorges area.By choosing 30 typical landslides in this area as examples,the stability state estimated by the revised BP-NN method is highly consistent to that by conventional transfer coefficient method.And the method presented in this paper has following advantages:the input parameters are easily obtained and this method does not deeply rely on investigation quality and shear strength parameters of slips and is a quite simple one.The BP-NN method is a new measure to stability analysis of landslides in the Three Gorges area,which is especially suitable to the stability prediction of landslides before investigation.     

Curvature Force Method for Nonlinear Analysis of Prestressed Concrete Frame

In this paper, based on the structure characters and load applying means, a method called as curvature force method is put forward and proved in the nonlinear analysis of bonded prestressed concrete frame. Based on the nonlinear program, the simulation calculation was carried out on test results of two prestressed concrete frames by this method. The results from calculation are identical with the experiment ones. So it may be added to the methods for the nonlinear analysis of prestressed concrete frame.     

金银花挥发油闪式提取工艺优化及在卷烟中的应用研究

为研究金银花挥发油的闪式提取条件及卷烟中的应用价值,采用响应面法分析并优化金银花挥发油的闪式提取工艺,选取提取电压,提取时间和液料比为随机因子,在单因素试验的基础上,根据Box-Benhnken中心组合方法进行3因素3水平的试验设计,以金银花挥发油得率为响应值,进行响应面分析（RSA）;并对金银花挥发油进行单料卷烟加香试验。结果表明：提取电压为151.61 V,提取时间为45.16 s,液料比为9.77:1为金银花挥发油提取的最佳工艺条件;在此工艺条件下金银花挥发油得率可达到0.1756%,拟合得到的模型较好地符合实际。闪式提取法是一种高效、快速提取金银花挥发油的方法。卷烟加香也表明：金银花挥发油具有改善和修饰卷烟香气、增加清香香韵、减轻刺激性的作用。金银花挥发油可用于卷烟加香。