阀厅结构悬吊设备地震作用的简化计算方法

针对带悬吊阀换流站阀厅结构悬吊设备设计方法上存在的欠缺,本文对悬吊设备的设计方法进行了分析研究。根据地震作用下带悬吊阀阀厅结构的非线性动力时程分析结果以及悬吊设备的特性,建立了地震作用下悬吊设备的计算模型,提出简化计算方法,并将该简化计算方法与其他计算方法分析所得结果进行对比分析,验证了该计算方法可行合理,可为带悬吊阀阀厅结构体系的抗震设计提供相应的计算依据。

滑坡与斜坡稳定性一般条分法分析中渗流作用的简化计算

当滑体或潜在滑体内有倾斜的相对弱面或端部条块外侧面倾斜且有水压力作用时,采用一般条分法进行稳定性分析应比采用垂直条分法更为恰当。本文研究了对一般条分法也适用的渗流作用简化计算方法,首先给出土条渗透力的合理计算式,再根据水的面力与体力的关系给出土条周边孔隙水压力计算方法。同已有的计算方法相比,本文方法的合理性显著提高。

位值制思想对小学数学教学的简化作用

所谓位值制,就是用不同的空间位置表示不同的值。如今在我们看来,感觉位值制是如此简单,实际上其在数学中的地位是相当重要的。如世界著名数学家拉普拉斯曾对位值制给予高度评价,他指出:"用十个记号表示一切的数,每个记号不但有绝对的值,而且有位置的值,这种巧妙的方法出自印度。这是一个深远而又重要的思想,它今天看来如此简单,以致我们忽视了它的真正伟绩。

浅析参数在解数学竞赛题中的辅助作用

有些数学竞赛问题,通过引入或挖掘辅助参数,使得这些参数在解题中起到联系分散条件,显示隐含因素,转化命题结构,简化解题过程,促成条件与结论的有机结合,进而起到“催化”和“桥梁”的作用。下面从四个方面浅析参数在解数学竞赛题中的辅助作用。

多馈入直流输电系统换相失败风险评估简化指标

换相失败是直流输电系统最常见的故障,受端系统交流故障是其最主要的诱因之一。对于大规模多馈入交直流系统,如何准确并快速地评估受端系统交流故障导致多回直流系统同时换相失败的风险,对于保障我国电网安全稳定运行、防止大停电事故发生具有重要意义。考虑电力系统实际运行情况,基于临界交直流系统电压耦合作用因子(critical AC-DC voltage coupling factor,CADVCF),推导出简化临界交直流系统电压耦合作用因子(simplified critical AC-DC voltage coupling factor,SCADVCF)的3种计算公式,解决了受端交流系统规模过大导致的计算繁杂的问题。针对直流系统额定功率运行和非额定功率运行的场景,分别给出了不同的换相失败风险评估方法。仿真结果证明了所提简化指标和评估方法的准确性和有效性。

导数在解高考题中的妙用

我们知道，函数是中学课本最重要、最基础的内容，它犹如一根红线贯穿其中，故历年的试题中函数的知识点和函数思想均占有相当的地位，但有些试题若能巧妙利用导数的知识则可以简化计算．下面几例是近几年的高考题，我们来看一下导数在其中起着怎样的简化作用．

巧用托勒密定理

托勒密定理是中学数学中应用比较广的一个重要定理，通过构造托勒密定理的条件，能对许多几何问题和代数问题的解决起到简化作用，也可以把代数问题几何化。我们应该重视托勒密定理，可使问题的求解过程变得简捷明快。

一类函数压轴题的解法初探

函数与导数压轴题，多与“任意性”或“恒成立”相关，常常含有参数，考查多层次的数学知识和能力．下面就这个方面的问题，从分离变量、极限与连续、导数等知识人手，以期对此类问题的处理起到一种简化作用，使解题过程更容易理解、操作更加简单，层次更加分明．

浅谈换元法在解题中的功能

换元法，就是把关于字母的解析式，用另外的字母或解析式表示的方法，是一种数学解题的常用方法，深入了解换元法在解题中的作用，有助于更好地利用换元法解题，有益于培养思维的灵活性和创造性．因此，要深刻理解换元法和培养用换元法解题的意识。

活用导数知识简解函数压轴题

关于函数与导数压轴题，多与“任意性”或“恒成立”等相关，有的含有参数，有的讨论非常繁琐．学生在处理这样的问题时，易错不全，甚至是一筹莫展．下面就这个方面的问题，改编了一下各地考试中的压轴题，从分离变量、极限与连续、导数等知识人手，以期对此类问题的处理起到一种简化作用，使解题教程更易理解、操作，使学习略显轻松．

Limit equilibrium stability analysis of slopes under external loads

Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip surface along the force action line, were considered. Meanwhile, four basic distribution patterns of external load were used, of which complex external loads could be composed. In analysis process, several limit equilibrium methods, such as Swedish method, simplified Bishop method, simplified Janbu method, Spencer method, Morgenstern-Price(M-P) method, Sarma method, and unbalanced thrust method, were also adopted to contrast their differences in slope stability under the external load. According to parametric analysis, some conclusions can be obtained as follows:(1) The external load, with the large magnitude, small inclination angle, and acting position close to the slope toe,has more positive effect on slope stability;(2) The results calculated using modes I and II of external load are similar, indicating that the calculation mode of external load has little influence on slope stability;(3) If different patterns of external loads are equivalent to each other, their slope stability under these external loads are the same, and if not, the external load leads to the better slope stability,as action position of the resultant force for external load is closer to the lower sliding point of slip surface.

Simplification of Double Folding Model Calculations in Study of Interaction Between Two Deformed Nuclei

The Double Folding （DF） model calculation of the internuclear potential in heavy-ion interactions when the participant nuclei are deformed in their ground states involves a six-dimensional integral. Using the multipole expansion in these calculations, the DF six-dimensional integral reduce to the sum of the products of three single-dimensional integrals. In this paper we have presented a procedure for the calculation of the radius dependent functions in the multipole expansion of the nuclear density and their Fourier transforms. We have also reduced the DF model integrals to the sum of the single dimensional integrals using the obtained relations for the radius dependent functions in the multipole expansion and their Fourier transforms.

Quadratic investigation of geochemical distribution by backward elimination approach at Glojeh epithermal Au(Ag)-polymetallic mineralization, NW Iran

The correspondence analysis will describe elemental association accompanying an indicator samples.This analysis indicates strong mineralization of Ag,As,Pb,Te,Mo,Au,Zn and to a lesser extent S,W,Cu at Glojeh polymetallic mineralization,NW Iran.This work proposes a backward elimination approach(BEA)that quantitatively predicts the Au concentration from main effects(X),quadratic terms(X2)and the first order interaction(Xi×Xj)of Ag,Cu,Pb,and Zn by initialization,order reduction and validation of model.BEA is done based on the quadratic model(QM),and it was eliminated to reduced quadratic model(RQM)by removing insignificant predictors.During the QM optimization process,overall convergence trend of R2,R2(adj)and R2(pred)is obvious,corresponding to increase in the R2(pred)and decrease of R2.The RQM consisted of(threshold value,Cu,Ag×Cu,Pb×Zn,and Ag2-Pb2)and(Pb,Ag×Cu,Ag×Pb,Cu×Zn,Pb×Zn,and Ag2)as main predictors of optimized model according to288and679litho-samples in trenches and boreholes,respectively.Due to the strong genetic effects with Au mineralization,Pb,Ag2,and Ag×Pb are important predictors in boreholes RQM,while the threshold value is known as an important predictor in the trenches model.The RQMs R2(pred)equal74.90%and60.62%which are verified by R2equal to73.9%and60.9%in the trenches and boreholes validation group,respectively.

三相异步电动机的自锁控制电路的探讨

三相异步电动机由于其结构简单,价格低廉,使用维护方便,坚固耐用等优点,因此在工、农业及其他各个领域中都获得了广泛的使用.据统计,我国及世界上一些发达国家,在所有的电能消耗中,电动机的耗能占60%～67%,而在所有的电动机的耗能中三相异步电动机又居首位.凡是控制三相异步电动机连续运转的控制电路中,都包含着接触器自锁控制这个基本电路的元素.