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刘兴辰 《东北林业大学学报》1993,21(2):100-105
对透视基本理论进行了推导,创立了一种新的视点内移作图法。这种方法是将视点移到图纸幅面之内。不用灭点而直接在水平投影图上作图,不但所占板面很小,而且能准确地定出视点位置,从而可容易地估出视观效果。方法简单,作图迅速。 相似文献
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本文总结了十五年来冬小麦育种工作的经验,结果表明,制定正确的育种目标是育种成败的关键.育种目标要适应生产的发展,要纠正脱离实际的过高的产量指标,在高产的基础上逐步改善品质.为了满足本地区不同条件下种植的小麦与其前后茬粮食作物,实现全年各茬均衡增产及连年持续丰产的要求,必须培育一整套品种,尤其要重视早熟品种的选育.还应要求冬小麦良种的性状在确保稳产的基础上去求高产;强调具备越冬抗寒性,抗多种病害,高抗倒伏,并能保持较大的生物学产量.文内设计及评价了产量构成因素不同组配的四种类型:多穗型、中间型、大穗(或穗重)型和耐晚播早熟型. 相似文献
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本文是研究透视仿射对应在正投影中,如何求直线和平面的交点,点到直线的距离,两平面的交线,平面与立体的截交线等问题。以解决在画法几何中作图繁、误差大的问题,达到提高解题速度,解决工程实际问题。 相似文献
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党的十六届三中全会明确提出的科学发展观使人成为社会发展的目标主体,反映了人类在发展理论上的不断深化.科学发展观的提出内含着深刻的人学思考.马克思主义人学理论为科学发展观的提出提供了理论根据.正因为科学发展观以马克思主义人学理论为指导,注重以人为本,才彰显了其科学性.也正是得益于坚实的马克思主义人学基础,科学发展观达到了对经济社会发展问题的新的更高的认识境界. 相似文献
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本文从地形林相图的网格高程数据矩阵出发,将隐藏线消除问题化为隐藏点的清除问题。并在此基础上定义两类隐藏点。通过三维图象的透视投影变换和与森林资源DBASE数据的联网,可绘制彩色森林立体专业图,并成功地解决了铁路线型库的问题。该系统为森林立体专业图奠定理论依据。 相似文献
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Jim Bender 《Agriculture and Human Values》1998,15(2):153-160
Jane Smiley's award winning and disturbing novel, A Thousand Acres, invites a critical appraisal of a popular assumption for proponents of sustainable agriculture: that family farming and sustainable agriculture are (at least indirectly) mutually reinforcing. This process begins with a plot that presents an Iowa multigenerational farm family headed by an acutely dominant father. Consequences of this dominance include subjugation of everyone involved with the farming operation, varieties of abuse of the daughters, and primitive non-environmental farming. Also in the novel three structural components of the family farm/rural setting aggravate the nightmarish situation: multigenerational participation in one farming operation, children remaining on the farm, uninterrupted, into adulthood, and the power of community appearances. It is argued that these components contribute not only to the family problems, but also to making the poor farming that emerges in this family not very coincidental. This analysis, if correct, raises many issues about farm structure and farming practices. They include how the younger generation(s) of family farm structures cope with their situations, whether aspects of family farms skew who decides to remain to farm, family farm ownership and transfer structure, how well farmers understand their own farms, and the case for voluntarism regarding environmental issues in farming. One theme throughout the essay is that the novel enables better recognition and appreciation of the subtle relationship between family problems and farming practices. 相似文献
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提出了目前的透视图不能作效果图的新论点,并从理论上进行了证明。同时也列出了改造目前透视图的几种方法,通过比较,确立了在透视图上增加带有标尺的图框线和指引线为最好形式。改造后的透视图不但可作效果图,而且也有反求功能。同时也使透视图的形式与其它工程图样相统一。 相似文献