After the students graduate from junior middle school , they only mast the ordinary knowledge and some of them ca n ' t even read newspapers well , still less mastering the technology of production and the knowledge of management . therefore , it is quite necessary to develop and do some research about the pattern of exbracurricular biology and scientific education for the peasants " service in the middle school in the countryside . secondly , this thesis sets forth the basis , current situation and aim about the pattern research of biology scientific education for the peasants " service 论文首先论述了在农村初中课程和教材中呈现的大一统形式，与城市学校课程及教材相差无几，缺乏地方性和特色性，由于片面追求升学率，很少涉及农村农业和农民问题，导致绝大部分学生不能成为优秀学生而白白浪费时间，造成学生不能学以致用，毕业回家时，只具备最基本的文化知识，甚至有的学生连报纸都念不下来，更谈不上掌握生产技术、管理知识，因此在国际基础教育课程改革的大背景下，发展农村初中课外生物科技教育为农服务模式的研究是完全可行和可能的，也是十分必要的。
Results show that the spatial distribution of the precipitation of the west is very uneven and obviously different in every quarter ; the characteristics of precipitation is droughty and less - rain in almost all part in winter . plentiful in summer , spring and autumn are transition phases , rainfall of autumn is more than that of spring in the most of region ; relative variability of each season rainfall is bigger than that of year , the variability is biggest in winter , but smallest in summer . alike between spring and autnmn and comprative in numerical value ; the area of least precipitation is in talimu basin and the northwest of chaidamubasin , not in the northwest of china 研究发现：西部地区年降水量的空间分布极不均匀，局地差异大；冬季绝大部分地区干旱少雨，夏季雨量丰沛，春秋季是过渡阶段，大部分地区秋雨多于春雨；各季降水量的相对变率大于年变率，夏季最小，冬季最大，春秋两季相似，数值上与冬季相差无几；我国雨量最少的地区位于柴达木盆地西北部和塔里木盆地，并不在我国的最西北角。
Though the water levels cross one section are almost equal , the velocities differ greatly . at the some cross - section , the velocity in the in the quirk may be double as that on the floodplain . the water surface will rise hi the southern branch because of the improper diffluence ratio , if using the designed diffluence col 淮河入海水道河口段水位值横向分布相差无几，而流速的横向变化较大，泓滩平均流速差最大可达一倍以上，在现有的分流口设计条件下，若按设计的南北汊分流比，南分流口有壅水现象发生，如果南汊分流增大到800m ~ 3 / s左右时，则水流较为通畅。
So it is not enough if we only execute linear analysis to a cable - stayed bridge ; 2 ) when live loads are distributed to full span the effects of geometric nonlinear for the structure are smaller than to two side spans or mid - span only ; 3 ) linear analysis is enough to live loads since the difference between linear analysis and nonlinear analysis to the structure is relatively small under live loads ; 4 ) the effects of every geometric nonlinear element to decision final shape parameters are very little , and the results of linear and nonlinear are nearly equal ; 5 ) under construction the effects of geometric nonlinear to cable - stayed bridges must be considered 2 )活载作用下，加载方式不同，非线性的影响结果也不一样，其中按全桥满布方式进行加载时受几何非线性的影响最小。 3 )活载作用下，可以用线性分析的手段对活载进行近似计算，以便减少计算量。 4 )各非线性因素对结构最终形态确定参数的影响非常小，线性结果与非线性结果相差无几。
