城市学校应特别重视劳动教育课

劳动教育是全面发展教育的重要组成部分,在学校教学中应占有重要地位。因为这门课负有教育学生热爱劳动,养成正确的劳动习惯和形成良好的劳动观念,树立以劳动为光荣,以好逸恶劳、不劳而获、奢侈浪费为耻辱的观点,以及培养学生掌握劳动知识、技能技巧的重任.然而,现今特别是城市学校劳动教育课却没有得到应有的重视.人们看到,今天的学生,尤其是大中城市的学生,一般家庭条件较好,对劳动的重要性和必要性认识很不够,劳动观念十分淡薄,谈不上什么劳动习惯,好象劳动与他们毫无关系,甚至认为劳动(主要指脏和粗的劳动)是种低下的可耻的事.这种现象对青少年全面发展的培养乃至对社会所起的作     

加强数学思想在交变电流教学中的渗透

在交变电流的知识体系中 ,一些物理量的制约关系 ,与数学中一些数量制约有着相似之处。正弦式交流电的图象与正弦曲线完全吻合 ,它们满足相同的规律。研究数学的思维方法 ,在交变电流中体现出来 ,在教学中渗透这种思想 ,可开阔学生思维 ,提高其解题能力     

师专有机化学实验课程改革的探索

文章根据师专有机化学实验的现状,提出改善实验环境,优化课程结构,规范操作训练,增加微型实验,开放实验室和严格考核制度等改革措施,并简要介绍实验教学改革的经验和实践效果.     

芍药属的研究(1)——国产几个野生种核型的报道

In the present paper 8 species with 15 populations of the genus Paeonia L. (if P. papaveracea and P. japonica are recognised as species) were collected from Sichuan, Shaanxi and Hebei provinces (see the Appendix for detail of the materials).  The micrographs of their somatic metaphase (also Mii in the case of P.veitchii) are shown in Plates 1-4, the karyo- type formulae, ranges of chromosome length and classification of karyotypes according to Steb- bins (1971) are shown in Table 5: the idiograms in Figs. 1-2, and the parameters of chromo- somes in Table 1-4.  The essential points are mentioned as follows:        (1)   Chromosomes of the various species in the section Modan have so far been examined and they are all diploid, the two species in the section Onaepia are also diploid, and thus tetraploids exist only in the section Paeonia.        (2)  Chromosomes in the genus Paeonia are relatively stable except for the differentiation of ploidy.  The karyotypes (Table 1-4) show no differences among different taxa in Sect. Modan and the same can also be said about the taxa in Sect. Paeonia (Table 1).  Not only are the karyotypes very similar, but also among the members within  either section have the same parameters of chromosomes, and, differences, if occur, are not statistically significant. Between the two sections, however, the situation is different. The arm ratios of the first pairs of chromosomes in Sect. Modan are 1.53, 1.52 and 1.48 (Table 1), but those in Sect. Paeonia are 1.12-1.28 (Table 2-4), 95% confidence limits are 1.46-1.60 for the section Modan and 1.07-1.28 (1.21-1.35 only for PB85078) for the section Paeonia, not overlapping, which indi- cates that the two sections have differentiated in respect of the first pairs of chromosomes.        (3)The population PB85024, which belongs to the P. obovata complex, has a karyotype of 2B (stebbins, 1971), which is a new one in the genus Paeonia. This karyotype is a stable one, for several individuals in the population are uniform in this respect, which shows that Steb- bins’ (1971) generalization that all the species in Paeonia have 2A does not hold true.        (4)  Three populations of P. obovata complex studied in this work from Sichuan and Shaanxi are all tetraploids, and one from Hebei is a diploid.  From the present work and the previcus reports, the materials from Japan and Korea, no matter whether flowers are pink or white, are diploids, those from Heilongjiang Province (with both pink and white flowers) (Liu Ming-yuan, personal communication) and from Heibei Province (with pink flowers) in China are also diploids, the one from Sakhalin (pink flowers) is tetraploid, those from Priamur of the Soviet Union are a tetraploid (with white flowers) and a diploid (with pink flowers), and those from Shaanxi (the Qinling Range) and western Sichuan (with both pink and white flowers) are all tetraploids.  As far as we have now known, ploidy in this parti- cular complex is correlated with the geographical distribution: diploids are found in the cen- tral part, tetraploids occur in the northern limits, and in the south  letraploids are the only cytotype.      (5)  The materials of P. mairei from western Sichuan and Shaanxi (the Qinling Range) are found all to be tetraploids, which shows that two cytotypes, diploid and tetraploid, exist in this  species,  but the geographical distribution pattern of these two cytotypes is to be revealed in the future investigation.     

浅析平锻机润滑系统的改进过程

主要论述的是SH315吨平锻机润滑系统从干油润滑到稀油润滑改进方案的确定过程.实现了稀油润滑系统的改进.经过改进后的润滑系统是一种循环的压力供油系统,可以及时地带走摩擦副产生的热量,也可以最大限度地减少摩擦磨损,还在润滑油的回收、保证经济效益等方面有着良好的效果.     

谈寒冷地区沥青混凝土施工质量控制

以207国道锡林浩特至桑根达来段为例,着重阐述寒冷地区沥青混凝土面层AC一16C密级配混合料的施工质量控制过程。锡桑公路全长156km,基层、底基层为水泥稳定级配碎石半刚性基层。设计强度为2．OMpa。面层为4cm厚的密级配沥青混凝土AC一16C混合料。目标配合比由天津市公路工程质量检测中心设计,并进行水稳和车辙试验,残留稳定度和动稳定度满足新规范要求。在实际施工中,特别强调是施工过程的质量控制,同时重视试验数据的准确性和指导性,发现问题及时处理。具体施工过程控制如下。     

VPN技术与知识产权保护及读者权益维护探讨

文章从法理角度讨论了尊重知识产权和维护读者权益间的矛盾,并介绍了利用VPN技术寻求两者间的平衡的尝试。     

如何写出一篇长文章?

正能写出一篇好长文的能力是不分专业和学科的,每个领域都需要。一个让你的独立思考能力快速提升的好方法是尝试写几篇一两万字以上、没有什么废话的长文章。要想学会写好文章,关键一点是需要你养成经常写的习惯。     

写好论文帮你建立思考框架

写论文应该是大学生大一就主动去尝试的行为,而不是等到大四才忙着复制粘贴。
　　剥笋法很直观地表明学习一门知识应该是“知其然更要知其所以然”。不带怀疑和批判的态度去学习是很难学到知识的。