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1.
In general,the calculating result of a comparatively regular frame-shearing wall system in tall buildings,a 4-order differential equations are established according to the deformation-coordination of beams,columns and four boundary conditions.Then a series of formulas concerning internal forces and displacement is obtained These formulas are hyperbolic functions.This paper presents a method,which changes 4-order differential equations into 2-order and solves them by the expressions of new homogeneous solutionThen the formulas of internal forces and displacements become exponential functions By this method,the calculation is very convenient The result of suggested method agrees well with the general by comparison This paper is also applicable to buildings with some part of different height of storey or stiffness.  相似文献   

2.
基于高光谱数据的滴灌甜菜叶片全氮含量估算   总被引:1,自引:0,他引:1  
本文旨在明确甜菜叶片全氮含量与高光谱地面植被遥感的定量关系,建立干旱区甜菜叶片全氮含量精确估测模型,及时监测甜菜生长状况。本研究选取新疆滴灌甜菜(Beta356)为材料,利用ASD野外高光谱仪在甜菜叶丛快速生长期、块根膨大期与糖分积累期采集各处理反射光谱,并同时测定全氮含量,分析原始光谱反射率及一阶微分光谱反射率与全氮含量的相关性,并进一步建立光谱特征参数与敏感波段植被指数全氮含量估算模型。结果表明,光谱特征参数Dr762幂函数下估算模型具有较好估算甜菜叶片全氮含量的能力,其决定系数R2=0.747,验证相对误差RE(%)为21.635,验证均方根误差RMSE为4.914;通过植被指数与叶片全氮含量建立多种函数估测模型,其中差值植被指数Dr762–Dr496下一元线性函数具有较好估算甜菜叶片全氮含量的能力,其决定系数R2=0.794,验证相对误差RE(%)为23.008,验证均方根误差为5.372。  相似文献   

3.
This paper proves some properties of the efficient margin in portfolio combinatorial investment and presents a methematical model for calculating the optimal weighted vector of portfolio combinatorial investment  相似文献   

4.
生物炭的结构及其理化特性研究回顾与展望   总被引:1,自引:0,他引:1  
建国以来,在党的正确领导下,我国作物育种和栽培研究工作,坚持理论联系实际、科学为生产服务以及“百花齐放、百家争鸣”的方针,取得了很大的成绩。为了适应形势发展的需要,中国作物学会自1962年起创刊《作物  相似文献   

5.
生物炭的结构及其理化特性研究回顾与展望   总被引:7,自引:0,他引:7  
作为新兴技术,生物炭技术及其应用在近年发展迅速,但由于来源、材质、炭化工艺等存在较大差异,导致生物炭特性及应用效果千差万别,研究结果难以比对甚至相悖,在一定程度上阻碍了生物炭研究与应用的发展。为此,本文从制约生物炭功效发挥的关键因素,即生物炭的结构及理化特性入手,系统梳理了近年有关生物炭的定义、形成、结构、元素及其主要理化特性和调控技术等方面的研究进展,总结分析了生物炭结构及其理化特性的共性、差异性特征及规律,厘清了有关生物炭特性及功能的基本观点、现状和共识。认为,生物炭的结构及其理化特性是影响生物炭作用、功能及效果的最主要因素,决定了生物炭的应用领域、范围、量级、目标和方向,采用改性或优化调控技术是发挥生物炭功效优势、潜力与价值的关键。并从资源与环境的"循环、可持续"发展角度,结合生物炭研究与应用实际,探讨了未来有关生物炭理化特性研究的基本原则和方向,旨在为生物炭基础科学研究与应用技术发展提供基础和参考。  相似文献   

6.
一种适合葡萄多种组织的总RNA提取方法   总被引:1,自引:1,他引:0  
为了解决葡萄组织中总RNA提取难度大的问题,以感染葡萄卷叶病毒-3的葡萄品种‘蛇龙珠’为试验材料,采用CTAB结合SDS法对总RNA提取方法进行了研究,建立了一套适合葡萄叶片、叶柄及韧皮部等多种组织总RNA提取的方法。结果表明,该方法在多种组织中均能获得高质量的RNA,OD260/OD280=1.8~1.9,电泳结果表明,所得RNA完整性好,无降解。同时用所得RNA进行了GLRaV-3的检测,电泳结果表明该法所得RNA可满足葡萄病毒病RT-PCR检测的质量要求。该方法操作简单,结果稳定,对其他富含多酚、多糖类植物组织总RNA的提取具有借鉴意义。  相似文献   

7.
史激光 《中国农学通报》2013,29(32):286-290
为了解锡林郭勒草地土壤主要养分的分布及变化规律,利用2006—2011年土壤主要养分测定资料,应用一元线性回归、线性倾向估计、相关分析等数理统计方法进行分析。结果表明:锡林郭勒草地土壤主要养分有机质、全氮、全磷、全钾含量分别为22.371 g/kg、1.053 g/kg、0.36 g/kg、23.737 g/kg,逐层0~5,5~10,10~20,20~30 cm含量变化趋势均随着深度的增加而递减,平均递减率分别为-0.361、-0.031、-0.004、-0.051 (g/kg)/cm,且存在一定的相关性。逐年变化趋势有机质呈显著上升趋势,趋势相关系数为0.8087,通过0.05显著性水平检验,上升速率为1.457 (g/kg)/年。全钾呈显著下降趋势,趋势相关系数为-0.903,通过0.001显著性水平检验,下降速率为2.4806 (g/kg)/年。全氮、全磷变化趋势不显著,变化速率分别为0.015、0.012 (g/kg)/年,不同草原类型土壤养分变化与总体存在一定差异。  相似文献   

8.
In this paper, the total input earthquake energy and influencing effects for shear type,shear-bending type, bending type aseismic structures of the single freedom system and multiple freedom elastic-plastic system are analyzed by synthesizing various effects and employing the timehistory analysis method. Based on the analysis results, the total input earthquake energy spectrum is presented.The simplified methods for analyzing the total input energy of multiple freedom elastic-plastic systems are proposed to provide some basis for developing aseismic structure design method and Double-Failure Criteria.  相似文献   

9.
This paper presents a new subgradient of set-valuedmapping and discusses its close properties and its no empty convexproperties.Under proper conditions,it proves to be true.  相似文献   

10.
以超声波辅助法对大兴安岭金莲花中总黄酮的最佳提取工艺条件进行研究。以温度、料液比、乙醇体积分数、超声时间为提取影响因素,通过正交试验优化提取工艺。结果表明,各因素对总黄酮提取的影响次序为:料液比>超声时间>温度>乙醇体积分数,超声波辅助法的最佳工艺提取条件为:提取温度为50℃,料液比1:55,乙醇体积分数75%,超声时间40 min,总黄酮的提取率达4.659%。  相似文献   

11.
According to the characteristics of plane strain problem of elastic and plastic mechanics, the bi parametric expressions were derived for stress components satisfying the generalized Hoek Brown failure criterion. Being substituted into the static equilibrium partial differential equations, a group of first order hyperbolic pseudo linear differential equation partial differential equations was obtained. Utilizing the determinant method and proper variable transformation, the characteristic direction and the differential relation equation for the stress partial differential equations were acquired. The characteristic direction indicted that in plastic zone obliquely intersecting conjugate shear slip surfaces formed two families of non orthogonal slip lines, in which conjugate angle varied with the limit stress state and the material physical properties of Hoek Brown rock mass. Since the principal direction of the maximum principal stress was circumferential in perfectly elasto plastic surrounding rock of the plastic zone around a circular opening suffering the symmetric initial stress field, the angle between the tangential direction of slip line with the principal direction of the maximum principal stress was the function of the minimum principal stress(i.e. the radial stress). Combined with the analytical solution, the polar coordinate differential equation was derived and furthermore, the polar coordinate curve equation for the slip line was obtained.  相似文献   

12.
服装热阻是影响人体热舒适的重要因素之一,夜间睡眠状态下的被服系统总热阻包括人体所穿服装热阻与整个床褥系统热阻。针对低气压环境,目前,尚缺乏被服热阻实验数据,也没有可参考的被服系统总热阻的理论计算模型。以人体睡眠状态被服系统总热阻计算方法为依据,引入气压修正项对相关参数进行修正,建立了适用于低气压环境的被服系统总热阻的修正计算模型,并用模型计算了冬夏典型被服系统总热阻,分析了气压减小对总热阻的影响,发现冬夏季被服系统总热阻均随大气压力降低而升高,增加百分比最大值均为42%,且均出现在被子覆盖率为23.3%的条件下,当海拔低于3 000 m时,由被子覆盖率引起的被服系统总热阻增加系数不超过0.05。  相似文献   

13.
回归克里格在土壤全氮空间预测上的应用   总被引:5,自引:2,他引:3  
王库 《中国农学通报》2013,29(20):142-147
精确地了解表层土壤养分的空间分布,是生态环境保护,合理施肥及精准农业的基础。普通克里格法以区域化变量理论为基础,在土壤空间制图中得到了广泛的应用,但该方法过分依赖样点数据数量和质量,忽视了影响土壤养分的环境要素,因而该方法在空间预测上存在缺陷。研究以使用环境辅助变量的回归克里格法在土壤全氮空间插值效果及空间制图应用,并与普通克里格做比较,对二者的制图效果及插值精度进行评价。结果表明,回归克里法能充分地利用容易获取环境辅助变量,预测精度明显地高于普通克里格。在制图效果上,回归克里格法得到的预测图更能体现环境要素的作用痕迹,预测图在空间上过渡自然、平缓,很少有在过渡区域表现突变的现象,制图效果更符合全氮空间分布的实际。因此,回归克里格法适合环境因素影响明确,且与特定环境要素存在线性相关或特定趋势的土壤属性的预测和制图。  相似文献   

14.
微波技术提取冰糖脐橙皮中的总黄酮   总被引:1,自引:0,他引:1  
采用微波技术,用碱性乙醇水溶液浸提、盐酸酸析,从冰糖脐橙皮中提取总黄酮。以总黄酮得率为评价指标,用紫外可见分光光度法检测,L16(45)正交实验筛选出的最佳工艺条件为:料液比1∶10,乙醇体积分数为60%,微波时间5min,微波功率350W,NaOH质量分数为1%。按优选的最佳工艺实验3次,总黄酮得率为6.11%,相对标准偏差(RSD)为0.43%(n=3)。  相似文献   

15.
This paper inferred a new high-speed method of tool-life testing from the differential median theorem of the pluralistic function. The characteristic of the method is that by using one cutting edge and doing one wear curve the tool life equation T=Cvx can be obtained.The drain on the workpiece and time of the method decreased by 2/3 as compared with that of the conventional testing method. The test has verified the method in the paper.  相似文献   

16.
The limit of convergent continuous function sequencemay be discontinuous.This makes difficults both in theory and applica-tion.For example,it makes the condition for operation of limits of integralof the function sequence become very strong.In general,it requiresuniform convergence to the function sequence.Therefore it is very imp-ortant to study such convergence as the limit of continuous function sequence,the limit is continuous.This paper studies a known substrong converg-ence of a function sequence in topological space and proves the necessaryand sufficient conditionof this convergence.  相似文献   

17.
利用乙醇提取法、热水提取法和碱提酸沉法,对小叶锦鸡儿不同部位的总黄酮提取进行比较。结果表明,利用体积分数70%的乙醇提取是一种比较好的提取方法。以乙醇作溶剂来提取小叶锦鸡儿不同部位的总黄酮,其中花中黄酮得率最高,达到2.16%,叶中次之,茎皮部最低。对小叶锦鸡儿黄酮类化合物作的定性检验结果表明,小叶锦鸡儿叶和花中可能含有黄酮类、黄酮醇类、异黄酮类、查耳酮和二氢黄酮类,茎皮部可能含有黄酮类、黄酮醇类、异黄酮类和查耳酮。  相似文献   

18.
研究了啤酒花CO2萃余物中总黄酮的提取纯化工艺。采用单因素试验确定乙醇体积分数、提取时间、提取温度和料液比对提取效果的影响;通过正交试验,得到最佳提取工艺条件为:乙醇体积分数为60%,料液比为1∶30,温度为70℃,提取时间为90 min,在该提取条件下总黄酮质量分数为62.7 mg/g;经饱和的水正丁醇溶液萃取,可得到纯度为20.3%的黄酮提取物;经聚酰胺树脂分离纯化,可得到总黄酮纯度为62.2%的提取物。  相似文献   

19.
曹凡  向阳  曾勇  廖勇 《中国农学通报》2016,32(27):165-170
由于油菜收获期南方气候阴雨潮湿,对油菜籽进行及时干燥非常重要。掌握油菜籽烘干特性和最佳烘干工作参数对于研制新型高效节能油菜籽干燥设备具有重要意义。本文基于总重检测原理研制了一种实验装置,实现了烘干过程中的参数控制和数据实时采集。应用该设备对油菜籽烘干特性进行了研究,以介质温度、穿透风速以及缓苏时间作为烘干特性的主要影响因素,以提高降水速率和降低单位能耗为研究目标,进行了单因素和多因素试验。试验结果表明,基于总重检测的油菜籽烘干特性研究方法具有结果直观、测量准确、数据连续性好的优点。并得到了油菜籽烘干最佳工作参数为:介质温度75℃、穿透风速0.358m/s、缓苏时间30min。  相似文献   

20.
After considering the features of the differential equations which have described the dynamic behaviours of HVDC systems, a fast algori -thm is presented for these equations. Compared with the fourth Runge-Kutta Method,this method has less amount of calculation with the same precision, numerical stability and other properties. Therefore, the use of the method has greatly increased the speed of the digital simulation of HVDC systems.In this paper an example of calculation is given, and the results obtained hv using this example are compared with the results obtained by calculating with the fourth Runge-Kutta Method. The speed of simulation by using this method is about 1.8 timss as fast as that by using the fourth Runge-Kutta Method.  相似文献   

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