共查询到19条相似文献,搜索用时 62 毫秒
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笔者发现在现行的中学化学课本中,所讲述的化合价与高校相关专业化学课本中的化合价定义是不相符的,因为在中学,化合价事实上主要讲的是氧化数的概念。在此,本文参考有关文献,结合化学键理论的发展,对化合价和氧化数的定义、数值确定及其区别做一简要的论述。 相似文献
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本提出一种名为选定氧化数法的配平方法,用于比较复杂的一元氧化还原反应方程的配平,把分散的各元素氧化数的个别计算和配平,归结为只有2种化学式氧化数代数和的计算和配平,应用十分简便,降低了配平的难度。 相似文献
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本文提出一种名为选定氧化数法的配平方法,用于比较复杂的一元氧化还原反应方程的配平.把分散的各元素氧化数的个别计算和配平,归结为只有2种化学武氧化数代数和的计算和配平.应用十分简便,降低了配平的难度. 相似文献
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本文用选定氧化数法配平有机氧化还原反应方程,避免了烃基碳氢元素繁多的氧化数的数值计算,使氧化还原反应方程中氧化数代数和不等于零的物质只有两种,只要配平这两种物质的氧化数的代数和即可。应用简便,降低了配平的难度。 相似文献
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用共价键的均裂和异裂法计算有机物各原子的氧化数 总被引:1,自引:0,他引:1
杨定乔 《黄冈师范学院学报》1997,(4)
应用Lewis的结构式,采用共价键的均裂和异裂方法,计算有机物分子中各原子的氧化数,方法简单,容易计算. 相似文献
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本文证明自然数方幂和可以用多项式表示,并用两种方法给出其系数包含Bernoulli数的几种精确表示式。 相似文献
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JACK M. WOLFE 《Journal of Educational Measurement》1971,8(3):221-222
Where two sets of measurements can each be grouped into below average, average and above average classifications with an equal number assigned to each of the below average and above average classifications, a 3 by 3 table can then be tabulated with frequency counts. The exact value of the product moment coefficient of correlation can then be calculated very simply by means of the formula, r = (DIFF)/2m, where DIFF is the difference between the sum of the corner numbers on the positive diagonal and the sum of the corner numbers on the negative diagonal, and m equals the number in each of the below average and above average classifications for each variable. The formula for r is applicable to negative as well as positive correlation. 相似文献
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糖类化合物手性碳原子R/S构型判别已在生物化学教学中引用,本文在教学实践中通过改写Fischer投影式,建立起几条改写规则,能达到快速、简捷判别手性中心R/S构型的效果。 相似文献
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孙俊逸 《赣南师范学院学报》1990,(Z1)
本文给出求可逆方阵的逆矩阵和利用线性代数方程组AX=b的系数矩阵A的一个初始近似逆阵P求解方程组的迭代算法,这种算法具有迭代格式简单,能有效地控制求解过程中的舍入误差的影响,灵活确定迭代次数等特点。 相似文献
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Christer Frey 《Learning, Media and Technology》1976,2(4):127-130
In Sweden radio and television programs for educational purposes are produced by a special unit within Sveriges Radio (SR), but there is also a production unit outside the organization SR producing educational programs, in the first place for adults (TRU). In the near future these two units are to be joined into one. In the Educational Program Department of SR there is a special group concerned with research and development questions. For the time being there are four full‐time posts as researchers, and within the framework of the budget of the program department the research group has it's own budget for research and evaluation of radio and television in instruction. The aim of this internal research ‐‐ exemplified in this paper ‐ is to give producers such experience as can be of value both for the assessment of individual products and for production work in the long run. 相似文献
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许洪 《昆明师范高等专科学校学报》1988,(1)
本文论证了用液体透镜法测量凸透镜的曲率半径和液体折射率可作为普通物理实验,着重指出实验的关键是设法测准透镜和液体透镜组的焦矩,介绍为测准焦距作者所设计的三孔挡光片,以及测量透镜的焦距的自准方法。 相似文献