一个定量讨论非含氧酸酸性强弱的公式

非含氧酸是无机酸中最简单的一种酸,它们的成酸元素是位于周期系ⅥA、ⅦA的元素。同周期元素或同族元素所成的非含氧酸其酸性强弱的变化规律,可以通过对成酸元素的电负性、原子半径数值的分析比较而得出。但是,在讨论非含氧酸时,往往不只是进行这种粗糙的相对比较,而需要了解各种非含氧酸的强度数值。因为只有了解到了各种非含氧酸的强度数值,才能严格地比较它们的酸性强弱。例如,氢硒酸、氢氟酸二者酸性强弱如何呢?显然从Se和F的电负性、原子半径是难以比较的。要解决这类问题,有待于进行具体的定量计算。     

无机含氧酸及其盐缩合性规律

本文对主族元素含氧酸及其盐缩合性规律进行了探讨,得出同周期含氧酸元素从左至右,缩合性减弱,以第二周期最为明显.同一主族元素含氧酸缩合性从上向下增强.易挥发的含氧酸,酸性又较强的,不易缩合,而难挥发的含氧酸,酸性较弱的容易缩合.影响含氧酸缩合能力的因素主要与酸的强度,成酸元素的电负性,中心原子R与O之间的作用能有关.     

影响无机含氧酸强度的结构因素

从无机含氧酸结构出发，研究了结构与酸强度之间的关系。     

短周期元素含氧酸及其盐缩合性探讨

从若干酸分子(盐)失去水分子形成多酸(多酸盐)的过程叫缩合反应.多酸亦叫缩合酸,其结构通常为链状、环状或笼状,那么含氧酸的缩合性与哪些因素有关呢?以下主要从酸强度、成酸元素的电负性以及中心原子与氧原子间的成键情况,来分析短周期元素含氧酸及其盐的缩合性.……     

短周期元素含氧酸及其盐缩合性探讨

从若干酸分子(盐)失去水分子形成多酸(多酸盐)的过程叫缩合反应。多酸亦叫缩合酸，其结构通常为链状、环状或笼状，那么含氧酸的缩合性与哪些因素有关呢?以下主要从酸强度、成酸元素的电负性以及中心原子与氧原子间的成键情况，来分析短周期元素含氧酸及其盐的缩合性。     

应用RAS法预见含氧酸的强度

RAS意指酸性相对强度(Relative Acidic Strength)。用它可以预见含氧酸的强度,其具体方法如下:     

含氧酸酸强度规律的研究

分析了影响含氧酸强度的主要因素 ,提出了一种含氧酸强度指数与元素在元素周期表中的位置间的计算方法 .     

含氧酸酸强度规律的研究

分析了影响含氧酸强度的主要因素，提出了一种含氧酸强度指数与元素在元素周期表中的位置间的计算方法。     

谈“含氧酸”一节的教法改进

师范院校化学专业现行教材［１］“含氧酸”部分是对非金属各论的高度概括和总结,为含氧酸的两大性质：酸强度和氧化性提供了重要的理论依据,对学生今后从事中学教学具有重大的指导意义。然而,在讲授这部分内容时,许多学生常感接受困难。究其原因,一是由于“含氧酸”教学涉及物质结构知识,本身很抽象,学生尤其是初学者理解比较困难;二是现行的许多教材由于篇幅限制,没能把一些实际问题加以归纳、总结。本文就此两点对“含氧酸”一节教学做经验总结,以帮助学生更好地理解和运用含氧酸的有关性质。现将想法、做法及体会分述如下：先…     

含氧酸强度特征与判断

根据含氧酸的组成和结构、鲍林的含氧酸半定量规则及有关的文献资料,提出了含氧酸的强度主要特征和含氧酸酸性判断规则,并列举文献资料数据进行论证．     

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?     

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…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.