评价机构传动质量的新方法-当量压力角法

对压力角和传动角作为衡量机构传动质量的不足进行了分析,提出采用当量压力角的合理性与实际意义.     

任意角和弧度制概念解读

一、课标要求1.初步理解用旋转定义角的概念;理解正角、负角、零角、象限角、终边相同的角的含义;掌握所有与α角终边相同的角(包括α角)的表示方法.2.理解弧度的意义,能正确进行弧度与角度的换算,学会利用弧长解决某些实际问题.     

例谈二面角的解法

在高考的立体几何试题中,求角是经常考查的问题,其中包括求线线角、线面角和面面角．求角的步骤都是“一作、二证、三算”,即先作出角,再通过推理论证某个角就是所求,最后再计算．而二面角的解法又是其中的重点、难点,下面介绍几种常见的解法,供大家参考．     

三角函数中的“缩角”策略

在解决三角函数的有关问题时，求值，尤其是求角是常见的题型，其解一般具有唯一性．为避免增解，需要缩小角的范围．如何缩角，学生常常感到很困惑．本文从以下6个方面阐述“缩角”的有关方法，以提高学生的思维能力和解题能力．     

浅谈同角三角函数基本关系式的应用

该文主要通过同角三角函数的三个基本关系式sin^2α＋cos^2α=1,tanα/cosα,tanαcotaα=1,初步探讨了同角三角函数关系式的几个基本的应用：1．根据一个角的某个三角函数值,求该角的其余的三角函数值;2．同角三角函数式的化简和证明。     

一个角与它的射影角的大小关系探索

如图 ,∠ＢＡＣ的两边ＡＢ和ＡＣ分别与平面α相交于点Ｂ、Ｃ ,若ＡＯ⊥α于点Ｏ ,则∠ＢＯＣ叫做∠ＢＡＣ图 (1 )在平面α内的射影角。显然若∠ＢＡＣ所在的平面与α平行或垂直 ,则∠ＢＯＣ =∠ＢＡＣ或∠ＢＯＣ =1 80°。下面将探讨一个角与它的射影角的大小关系。一个角∠Ｂ     

再谈三角新体系

笔者在[1]中提出建立以和角公式为纲的三角新体系,将诱导公式调整到和角公式之后,由和角公式导出,使三角的恒等变换成为一个完善的演绎体系:三角函数的定义——同角公式—和角公式——诱导公式;倍角公式;和差倍化积和积化和差这是针对传统教材而提出的。在传统教材中将诱导公式安排在和角公式之前,中间用三角函数的性质隔开,自然造成诱     

角概念的再认识与教学策略

数学中的"角"将学生的思维从一维拓宽到二维,为了使学生更好地学习,教材特意将"角知识"分布在两个学段,形成知识螺旋。通过对角概念的再认识,提出了角概念的四个教学策略,有利于提高教学效果。     

Harris角点检测算法的实现及应用效果分析

Harris角点检测算法是一种非常有效的图像角点提取算法,提取的角点稳定可靠、均匀而且合理。用C#语言实现了Harris角点检测算法实现程序,并结合图例分析了该算法各种参数的设置。     

三分角与双曲线

三等分角问题是二千四百年前，古希腊人提出的几何三大作图问题之一。三分角问题虽是无解的，但人们在研究三分角的过程中发现了双曲线。章就三分角问题分析了三分角双曲线的性质、机械作图法并在此基础上研究对某一角的任意等分问题。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.