唤起“求知欲”，治疗“厌学症”

本文分析了求知欲的由来及消退原因，“厌学症”的形成及治疗方案，试图唤起学生的求知欲，治疗他们的“厌学症”。     

Cells of the connective tissue differentiate and migrate into pollen sacs

In angiosperms, archesporial cells in the anther primordium undergo meiosis to form haploid pollen, the sole occupants of anther sacs. Anther sacs are held together by a matrix of parenchyma cells, the connective tissue. Cells of the connective tissue are not known to differentiate. We report the differentiation of parenchyma cells in the connective tissue of two Gordonia species into pollen-like structures (described as pseudopollen), which migrate into the anther sacs before dehiscence. Pollen and pseudopollen were distinguishable by morphology and staining. Pollen were tricolpate to spherical while pseudopollen were less rigid and transparent with a ribbed surface. Both types were different in size, shape, staining and surface architecture. The ratio of the number of pseudopollen to pollen was 1:3. During ontogeny in the connective tissue, neither cell division nor tetrad formation was observed and hence pseudopollen were presumed to be diploid. Only normal pollen germinated on a germination medium. Fixed preparations in time seemed to indicate that pseudopollen migrate from the connective tissue into the anther sac.     

大气环境影响评价的不确定性分析

就我国大气环境影响评价目前存在的问题进行了阐述，提出了应当正确引导和规范大气环境影响评价，发展“标准化”的计算方法和评价方法，使影响预测结果具有代表性的可比性。     

天然河流纵向离散系数的最优化计算方法及其应用

提出了计算天然河流纵向离散系数的最优化方法，并用此法对岷江蕨溪段的试验数据进行处理，计算出了该段河流的纵向离散系数。     

浅谈对管理者的安全教育

"安全生产,教育为本",管理者安全教育是企业全员教育的重要组成部分,加强对管理者的安全教育是新世纪现代企业管理中的一项新的课题,是上级主管部门、企业党委和行政领导的一项重要的任务,是能否抓好安全生产,使各项工作顺利开展的关键.     

课堂教学案例开发的思考和实践

本文通过对教学案例涵义及类型进行分析,提出教学案例开发思路与方法,说明案例开发在培养人才中的作用和意义。     

英国的医疗废物分类管理方法

本文简要介绍了英国对医疗废物的分类，以及根据废物管理的等级制度．对医院垃圾实行的分类收集方法．以期能对我国完善有关医院垃圾分类收集的规章制度提供建议。     

川中丘陵区典型土地利用方式下磷素迁移的初步研究

通过野外定位观测,对川中丘陵区坡耕地、水田与林地地表径流水中磷素迁移形态、迁移通量进行了初步研究。结果表明,坡耕地、林地磷素迁移以颗粒吸附态为主,水田磷素迁移以水溶性磷为主,所有土地利用类型径流中总磷含量已超过水体富营养化的标准。坡耕地、水田和林地地表径流水中磷迁移的通量分别为0.88 kg/(hm2.a),0.15 kg/(hm2.a)与0.33 kg/(hm2.a)。     

沈阳市“十一五”期间的空气污染防治

根据沈阳市环境空气面临的问题,确定“十一五”期间空气环境质量保护目标、指标,提出改善空气环境质量的对策措施,保证沈阳市大气环境质量的持续改善。