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1.
We suggest a class of generalized Newton method in this paper. As special exampls, it contains the usual Chebyshev method, tangent-hypobolic method and steepest descent method.  相似文献   

2.
Some new developments of boundary contour method have been presented in this paper. The developments include the boundary contour method based on equivalent boundary integral equations, the traction boundary contour method as well as the application of the boundary contour method to crack problems and elastic thin plate bending problems.  相似文献   

3.
A new method with which to calculat the displacements of beams and frames is presented. The areas of tending moment diagram of beam or frame and the slope at the origin of the elastic curve are treated as some rotatable vectors with this method. Angular displacement and in-line displacement can be calculated by using the projection and moment of these vectors. This method can be used to calculate displacement of the bar and the bar syttem ( including three dimensional forms. ) , which made from linear or ncnlinear elastic materials. The cross section of the bar is changeable.  相似文献   

4.
3种椰子基因组DNA提取方法的比较   总被引:1,自引:1,他引:0  
旨在得到一套快速提取椰子DNA的方法。采用CTAB小样法、SDS-CTAB法以及PVP法提取椰子组织的DNA,并通过后续的PCR扩增和酶切等实验比较了3种方法所提取的DNA质量的优劣。将CTAB小样法提取的DNA与SDS-CTAB法和PVP法提取的DNA进行了比较,CTAB小样法提取的DNA的OD260/OD280(1.839)较另外2种方法SDS-CTAB法(1.709)和PVP法(1.613)的值更高,CTAB小样法提取的DNA适合于PCR扩增,扩增的条带清晰,且特异性好。此外,CTAB小样法提取的DNA,酶切也较为均匀。CTAB小样法能高效地提取椰子的DNA,并且能一次提取大量的高质量DNA样品,因而能满足高通量的实验要求,同提取DNA能较好地满足下游的分子生物学研究。  相似文献   

5.
三角褐指藻是一种含有较高多不饱和脂肪酸的海洋单胞藻。为了从细胞中提取不饱和脂肪酸,采用反复冻融法、超声波破碎法和匀浆法分别对三角褐指藻细胞进行破碎,并测定油脂提取率。结果表明,超声波破碎法、反复冻融法和匀浆法的最大细胞破碎率分别为91.5%,56.7%和81.2%;油脂提取率分别为18.1%,13%和13.4%。从操作的简捷性和经济效益来看,超声波破碎法优于反复冻融法和匀浆法。  相似文献   

6.
三种方法提取大肠杆菌E.coli脂多糖的比较   总被引:1,自引:0,他引:1  
康洁 《中国农学通报》2010,26(21):12-15
寻找大肠杆菌E.coli脂多糖的最佳提取方法。分别用改良热酚法、超声波处理法、煮沸法从大肠杆菌细胞壁中提取脂多糖,经纯化后分别在721分光光度仪上测其吸光值;再用三种方法提取的脂多糖分别免疫草鱼,计数法测受试草鱼血液中白细胞的数量,愈创木酚法测受试鱼不同组织中过氧化氢酶的活力(用OD值表示)。改良热酚法、超声波处理法、煮沸法提取的脂多糖在稀释15倍时其吸光值分别是1.973、1.003和1.153;改良热酚法、超声波处理法、煮沸法提取的脂多糖在稀释15倍时免疫草鱼,测得受试鱼的白细胞数量分别为159个/μL、160个/μL和135个/μL,测得受试鱼血液中的过氧化氢酶活力分别是0.09、0.083、0.078,测得脾脏中的过氧化氢酶活力分别是0.083、0.078、0.06。结论改良热酚法提取的大肠杆菌脂多糖浓度高、免疫活性强,是相对比较好的一种提取方法。  相似文献   

7.
双波长分光光度法测定土壤硝态氮的可行性研究   总被引:8,自引:0,他引:8  
为了探寻简单、快速的土壤硝态氮测定方法,以指导农业生产氮肥施用,对双波长长法测定土壤硝态氮的方法进行了探讨,并与广泛应用的反射仪法和流动分析仪测定方法进行了比较,结果表明双波长分光光度法与反射仪测定和流动分析仪测定方法高度相关,操作简便、准确,可用于土壤硝态氮的测定。  相似文献   

8.
不同尺度农田水分利用效率测定方法评述   总被引:3,自引:0,他引:3  
摘要:水分利用效率是反映作物物质生产与水分消耗之间关系的指标,在不同的学科存在不同的理解,在不同尺度有不同的计算方法。本文评述了收获法、红外气体分析法、涡度相关法、稳定同位素法测定水分利用效率的优缺点及其适用的尺度。  相似文献   

9.
以新鲜米糠为原料,采用碱法、酸法、盐法分步对米糠蛋白进行复合提取。在提取过程中,以蛋白质提取率为指标,确定料液比、pH值、温度、时间对米糠蛋白提取率的影响,通过正交试验确定这3种方法各自提取蛋白的最佳工艺,最后依次采用碱提、酸提、盐提的最佳工艺条件分步对米糠蛋白进行提取。结果表明,碱法提取新鲜米糠蛋白最佳工艺条件:时间2.5 h,pH值12,温度30℃,料液比1∶11,提取率为34.49%;酸法提取新鲜米糠最佳工艺条件:时间3 h,pH值0.05,温度35℃,料液比1∶11,提取率为25.88%;盐法提取新鲜米糠蛋白最佳工艺条件:NaCl浓度0.6 mol/L,温度35℃,料液比1∶11,提取率为15.66%。复合法提取新鲜米糠蛋白总提取率达60.12%。  相似文献   

10.
The transfer substructure method is extended to application in substructures with different linking ways,thus the field of application of this method is expanded. Its relaibility and efficacy are proved by some examples.  相似文献   

11.
Some paper have presented the abstract element class of FEM, which the specific element class such as the triangle Element,the quadrilateral Element can be derived from. The substructure is the specific element class as the class derived form the abstract element class. The Object-Oriented FEM needs changing rearly when the sub-structural function is added to it. The Choleshi's disintegration of the sub-structural stiff is done and using the resolved triangular matrix many times can greatly reduce the work of the cohering matrix. The definition of the substructure class and the comparison between the sub_structural method and the normal method.  相似文献   

12.
《保鲜与加工》2003,(10):39-41
Galerkin method based on the variation principle is used to solve differential and integral equations. The boundary problem of Laplace equation is changed into the variational equation which is equivalent to the boundary integral equation. Using linear element, it is solved by Galerkin boundary element method. In computation of stiffness matrix, the exactly integral formula is used in the first order integral expression, The numerical integral formula is used in the second order integral expression. Thus the problem of calculation of double singular integral is carried out. The numerical experiments also prove this method is reliable. The error of Galerkin boundary element is tested with numerical experimentation.  相似文献   

13.
Based on object-oriented method, the classes of object-oriented finite element are defined. The finite element program of static, dynamic characteristics and stability analyses for spatial frame structures is developed with c++ object_oriented language which is successfully incorporated into a computer simulation system of derricks. The results of static, dynamic characteristics and stability analysis for the derricks of F320-A and JJ250/42-K types, obtained with the developed system, are consistent with those obtained by a commercial software, which illustrates the correctness of object-oriented FEM and the reliability of the simulation software.  相似文献   

14.
A symmetric successive over ralaxation preconditioned conjugate gradient method is used to calculate nonlinear electromagnetic field. The storage and the computer time of the method discussed hfire are compared with those of Newton's iteration.  相似文献   

15.
湖南水稻干旱评估方法研究   总被引:2,自引:2,他引:0  
为了探讨双季早稻、双季晚稻、一季稻干旱影响定量评估方法,统计各熟制水稻各生育期综合气象干旱指数、水分亏缺指数与水稻受旱率、成灾率、单位面积粮食减产量的相关,分析各熟制水稻干旱影响敏感期;基于相关系数,定量计算综合气象干旱指数、水分亏缺指数组合成综合评估指标所占的权重,组建各熟制水稻旱情综合评估指标;基于各熟制水稻旱情综合评估指标,结合抗旱能力,通过多元回归建立各熟制水稻受旱率、成灾率、单位粮食减产量评估模型。结果表明:(1)湖南季节性干旱特征明显,对于双季晚稻,各生育期干旱出现频率基本接近,干旱影响期为返青分蘖期和幼穗形成期;双季早稻、一季稻各生育期干旱出现频率差异较大,以水稻生长后期干旱出现频率高,而水稻干旱影响敏感期也在水稻生长后期。(2)双季早稻干旱灾害评估模型历史同级拟合率平均为77.6%,级差一级以下的拟合率为91.1%;双季晚稻同级拟合率为70.9%,级差一级以下的拟合率为83.0%;一季稻同级拟合率为61.8%,级差一级以下的拟合率为84.5%。基于降水、需水、可供水等因子建立水稻干旱灾害评估模型,物理意义清楚,准确率较高,可为水稻干旱影响定量评估提供技术支持。  相似文献   

16.
This paper presents the numerical implementation of boundary element method incorporated into a non overlapping domain decomposition method for solving the Navier equations of linear elastodynamics problems by Fourier transformation. Several examples are presented.  相似文献   

17.
大豆杂交种异地鉴定及选育方法初探   总被引:2,自引:2,他引:0  
为了研究大豆杂交种杂种优势大小及其稳定性,进一步探讨杂交大豆选育方法,通过对2006—2010年异地鉴定试验初次测产及二次测产结果进行分析。结果表明,大豆杂交种同常规对照品种比较,具有较强的杂种优势,增产效果显著。大豆杂交种各产量性状间差异明显,这是由杂交种的遗传基础决定的,与杂交种的亲本的遗传基础及配合力有关。杂交种产量优势主要来自于三粒荚数、四粒荚数、单株荚数、单株粒数、单株产量、分枝数等产量性状,为杂交大豆新品种选育提供了依据。同时指出了大豆杂交种异地鉴定中存在的问题及解决方法。  相似文献   

18.
澳洲坚果叶面积测定方法比较   总被引:2,自引:0,他引:2  
为确定不同品种澳洲坚果叶面积测定的最佳方法,找出系数回归法测量澳洲坚果叶面积的最佳参数,对3种叶面积测量方法进行比较,对不同叶片参数与叶面积间的关系进行回归分析。结果表明,同一品种经方格法、画纸称重法、图像处理法测定的叶面积均无显著性差异,3种方法测定结果的相关系数都在0.999以上,说明3种方法均可作为澳洲坚果叶面积测定的可靠方法;不同品种的各叶片参数与叶面积间的回归系数并不相同,在利用系数回归法测量澳洲坚果叶面积时,叶长宽积是最能反映实际叶面积的叶片参数。本研究可为澳洲坚果的生理研究和生产实践提供重要参考。  相似文献   

19.
In this paper, a dynamic substructure method for analysing the transient response of the large structure is proposed. The method is based or, the combination of the reduced dynamic-stiffness composition method and the step-by-stop integration method. Its main feature is that the computational effort may be reduced significantly. Several examples are given to prove its reliability, effectiveness and accuracy.  相似文献   

20.
综合介绍了有机生产中控制有害生物的技术措施,主要有:生态学技术措施、农业措施、物理措施以及生物药剂防治措施等,为有机农业生产中有害生物的管理提供了思路和方法。  相似文献   

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