ON THE STUDY OF THE INFLUENCE OF MASS DISTRIBUTION ON DYNAMIC CHARACTERISTICS OF A SPINDLE SYSTEM WITH MODALITY ANALYSIS METHOD

The modality analysis method is employed in this paper to study the influence of mass distribution on dynamic characteristics of a spindle system. It is found that there exist obvious difference between the influences of different mass distribution on the natural frequencies . and modality flexbilities of various order-mode. It is shown that the proportion of modality flexbility in the astatic flexbility can be equilibrated by means of adjusting correctly the mass distribution of the spindle system so that the cutting stability is improved as well. Experiment results are quoted to confirm, in a certain degree, the conclusion above.     

INFLUNCE OF THE SPINDLE TURNING ON STATIE DYNAMIC CHARACTERISTIC OF HYDROSTATIC GRINDER HEAD OF PROFILE GRINDING MACHINE

The theoretical analysis and testing result indicate that, a hydrodynamic effect will be taken under place the condition of a turning spindle which will rise the rigidily of the spindle system and strengthen its antivibration ability as well. Below a critical turning, speed, itis discivered that the high the turning speed is, the more obvious hyrodynamic effect and the letter static and dynamic characteristic would be.     

DYNAMIC ANALYSIS OF WET-BOTTOM BOILER WITH OPEN FURNACE

The dynamic caclucation and analysis for a wet-bottom boiler with open furnace is presented in accordance with its structual and thermal parameters.     

A DYNAMIC ANALYSIS OF UNSYMMETRICAL FRAMEWALL STRUCTURE

The frame-wall structure is good both in operational performance and mechanical property. In this paper, the shear-wall is considered as a cantilever thin-wall member, and the frame as a multistoreyed shear model. The theory of structural matrix is used to get a series of stiffness matrix formulas of theunsymmetrical framewall structure. The Largrange equation is used to get dynamic equation of the structure in the form of matrix. At last a 43 storeyed model of unsymmetrical frame-wall structure is calculated, the result is close to the test.     

DYNAMIC ANALYSIS AND NUMERICAL METHOD IN PHE DRIVE MECHANISMS OF THE STEEL-TUBE COLD-ROLLING MACHINE

In this paper, the calculating formulas for partial dynamic balance of crankslider mechanisms are derived in terms of the limear independent vector theory. The driving torque and the optimum selections for partial dynamic balance in drive mechanism of the steeltube cold-rolling machine are carried out. The method in this paper has a universal reference meaning for the partial dynamic balances of crankslider mechanisms.     

THE ELESTOPLASTIC DYNAMIC ANALYSIS OF RC PLANAR FRAMES AND ITS PROGRAM

This paper makes use of a beam-colunm model in the elastopl-astic dynamic analysis of RC planar rames.For which an improved method is presented to estabish the envelopes of moment-curvature relationships by appli-cation of RC nonlinear analysis,and a program named PFEPDA suitable to mic-rocomputer is developed.     

AN ANALYSIS ON ELIMINATING NOISE OF AE TEST BY SIMULATOR AND THE KAISER EFFECT

In the utilization of the Kaiser Effect of AE as a method of estimating the gecstress in rock, it is very important to eliminate the noise induced at the ends cf a specimen, so sponge pads are put between the upper and lower end surfaces of specimens and bearing plates. In this paper, the attenuation behavior of sounds emitted by AE simulator and propagating in sponges are quantitatively measured. The eliminaion of noise by sponge effect is confirmed by the Kaiser Effect.     

A METHOD OF SYSTEM IDENTIFICATION AND MODEL REDUCTION BASED ON TIME-DOMAIN RESPONSE OF A DYNAMIC SYSTEM

This paper combines model reduction with system identification by means of time-domain function approximation, and presents a new time domain method of direct identification of linear reduced model and model reduction, and demonstrates existence theorem of its solution and criterion of order determination. Simulation tests show that the method is simple, accurate with few data requirement.     

关于沙漠化概念的意见分歧及其成因浅析

科学概念对于学术交流和科学研究很重要。针对当前学术界关于沙漠化概念意见分歧很大的原因,本文查阅了大量文献,分析了学者们提出的不同沙漠化概念及其产生分歧的原因,研究结果表明：（1）沙漠化成因是沙漠化概念产生分歧的原因所在;（2）我国北方沙区曾经历过沙漠化正、逆过程的波动,其中有自然成因,也有人为成因,所以沙漠化概念不应局限在成因问题上;（3）沙漠化就是因风力而形成的沙质荒漠化。     

20%高渗毒死蜱乳油防治棉花棉铃虫田间药效试验初报

20%高渗毒死蜱乳油在二代棉铃虫发生盛期防治,每公顷施用有效成分270g时药后1、3和7d的矫正防效分别达83.99%、89.08%和89.73%,速效性和持久性均显著优于12%路路通乳油每公顷施用量1800ml效果（67.63%、74.61%、76.54%）。从保顶效果看,20%高渗毒死蜱乳油每公顷施用有效成分270g时为89.30%,显著优于对照12%路路通乳油1800ml每公顷施用效果80.70%。     

ORTHOGONAL COLLOCATION METHOD AND IT APPLICAIONS IN THE CALCULATION OF DYNAMIC CHARACTERISTICS OF HEAT EXCHANGER

Being a kind of MWR, the orthogonal colloacation method can be conveniently used to reduce the initial-boundary value problems of the partial differential equations to initial value problems of ordinary differential equations. In this paper, the orthogonal collocation method is introduced in detail and by using it the dynamic characteristics of a steam-water heater are investigated.     

Power Lines Icing Characteristics of the Three Gorges District and a Model of the Accumulation of Ice on Electric on Electric Power Lines

Based on the study of accidents investigation of the electrical power lines because of icing in the district of Three Gorges,this paper analyzes the icing conditions and characteristics of various ice accreted and develops a model of the accumution of hard rime on electrical lines.     

Study on Compensation Standard of the Urban House Dismantlement Based on Game Theory

It is a hot question in recent years in China about the urban house dismantlement and development, and the low compensation standard of the urban house dismantlement has been thought to be the main reason that cause dispute of the urban house dismantlement. After a two-player game model is built, the paper solves mix-strategy Nash equilibrium of game and analyzes the influence of improving compensation to game equilibrium. It is concluded that, if government only improve policy of compensation standard to issue, the resident ready to move with their house to be dismantled can enjoy the great benefit shortly, but the long-term policy result is to reduce the incidence of the urban house dismantlement and slow down paces that the old city transforms.     

青海高原放牧藏母羊规范养殖技术的研究

本文就青海高寒草地放牧藏母羊的规范养殖技术进行了探索。通过高寒草地放牧绵羊4种不同生产模式研究,结果表明：生产模式Ⅰ和生产模式Ⅱ,羔羊初生重、2月龄重及2月龄日增重有极显著差异 (P<0.01);生产模式Ⅰ和生产模式Ⅱ母羊产羔率和2月龄羔羊的成活率高于生产模式Ⅲ和生产模式Ⅳ,差异极显著(P<0.01);生产模式Ⅰ和生产模式Ⅱ母羊生产单位羔羊利润明显高于生产模式Ⅲ和生产模式Ⅳ,达到了牧民增收,减少天然草场载畜量,保护草地生态的目的,最终实现了“保护草地生态,增加牧民收入”双赢的高原藏母羊生产模式。 关键词： 放牧绵羊,羔羊,生产模式,断奶重,繁殖成活率     

A Description for Pseudoelasticity and Shape Memory Effect of SMA

Pseudoelasticity and shape memory effect(SME) are the most fundamental properties of shape memory alloys (SMAs), which can be attributed to the combination of the individual property of each phase of SMAs that are dynamically composed of austenite and martensite. Based on the theory of mixture, a constitutive model is proposed, in which, the behavior of austenite is further assumed to be linear elastic while that of martensite elastoplastic. The behavior of SMA under different temperature is described and compared with experimental observation. Compared with the existing model, the proposed model is simple, physically distinct and can easily be applied in practical engineering problems.     

An Approach for Estimating the Final Ultimate-bearing Capacity of Driven Pile In Soft Clay

The prefabricated pile,driven in soft clay,can squeeze the soil laterally in a certain scope around the pile,and the void ratio is reduced significantly;consequently,the shear bearing capacity is raised.But the soil parameter,which is used to estimate the capacity of pile,is reduced according to the soil state before the pile was driven.Then,a certain difference appears when the pile is working.The calculation result usually is partial to conservative.This paper analyzes the squeezing mechanism of the pile using the theory of cylindrical cavities expansion.And a formula,which is used to estimate the increment of shear bearing capacity of soil around the pile when excess pore water pressure from pile driving distributes completely,is presented based on the unique relation between the shear bearing capacity and the density of the soil.This formula can be used to estimate the final ultimate-bearing capacity of the pile.The calculated results by the proposed formula are in good agreement with those of the site measurement.     

永久基本农田后期管护中农民参与意愿及其影响因素研究

研究旨在从农民参与意愿角度剖析其在永久基本农田后期管护的影响因素,以改善永久基本农田"重建轻管"的现状,为永久基本农田后期管护提出建议和对策.运用二元Logistic模型,根据河南省洛阳市新安县的485户农户对永久基本农田后期管护意愿的问卷调查数据,以农民参与永久基本农田后期管护意愿为因变量,从个人基本特征、家庭基本特...