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虚拟树木生长建模及可视化研究综述 总被引：9，自引：1，他引：9
虚拟树木,就是应用计算机模拟树木在三维空间中的生长发育状况,近年来已成为植物学、农林业、环境科学和计算机领域的研究热点.生长模型和可视化技术是它的核心内容.虚拟树木生长模型包括形态结构模型、功能模型和结构-功能模型等,其中结构-功能模型可以模拟树木与环境间的相互关系,其结果为树木的三维结构,因此它最为接近现实树木的生长,是虚拟树木生长模型的发展方向.树木形态的复杂性与计算时间和空间的矛盾一直是可视化研究中的难点.树木可视化还有不同于其他物体的特性,如多级分枝、枝条的弯曲、自相似、向光性、树木分枝间的光滑与非光滑连接等.树木可视化软件可分为2类:纯图形学软件和基于结构-功能模型的软件,其应用已涉及娱乐、商业、计算机辅助景观设计、教育、科研和林业生产等方面;但在树木构筑型数据的采集和管理、结构-功能模型的建立、树木可视化技术的研究及面向林业生产等方面仍需要大量的工作. 相似文献
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林木虚拟生长模型是应用计算机模拟树木在三维空间中的生长发育状况,而农药精确施用模型是应用计算机模拟农药按需定量喷施、与目标植物接触以及产生药效等一系列喷施作业情况。如果把两者耦合起来,将直观模拟出林木正常生长、受病虫害侵染、农药发挥效果、长势有所好转等一系列交互效果,可为调整植物保护策略、制定农药喷施方案和研制新型植保机械提供理论支持和技术支撑。文中分析了农林病虫害防治情况和农药精确施用的重要性,在综述国内外喷头雾化性能模型、沉降沉积模型（飘移模型）、施药量调节模型、雾化特性预测模型等农药施用模型研究现状的基础上,通过分析探讨两模型协同机理和林木虚拟生长模型及耦合模型实时性协同环境,提出了基于农药施用过程与防治药效的模型协同研究、基于林木形态结构模型的仿形对靶喷雾模型研究以及农药精确施用多模型交互协同研究的建议。 相似文献
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结构—功能模型在林木竞争研究中的应用 总被引：1，自引：0，他引：1
林木结构-功能模型是指能明确表达由林木生理过程和环境因子调控的植物三维结构生长和变化的一类模型, 其既考虑了树木结构的发展, 又考虑了树木生理生态过程和环境之间的交互影响。文中探讨了林木竞争经验模型的研究应用, 认为其存在的不足是缺乏反映树木内部资源获取与分配的生理生态指标以及着枝个数、枝条长度等形态属性指标等; 以目前几种主要的结构-功能模型为例, 对其在林木竞争研究中的应用以及对竞争表达的改进方面进行了评述, 最后指出目前结构-功能模型在林木竞争研究中存在的问题及未来的应用前景。 相似文献
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基于3ds Max的虚拟校园三维模型的创建 总被引：3，自引：0，他引：3
研究了基于3ds Max软件的虚拟校园三维模型的创建方法,具体讨论了校区三维建模的流程、建筑三维模型的创建、其它地物模型的创建,利用3ds Max软件建模,创建了东北林业大学校园建筑物三维模型。 相似文献
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采用ADAMS对虚拟样机进行运动学和动力学分析具有准确、方便的特点,而MATLAB能实现对虚拟样机的复杂控制。利用ADAMS和MATLAB软件提出了一种简便的飞轮转子等效动力学模型和控制系统模型的建模方法,推导出飞轮转子系统的振动数学模型并进行了静态悬浮联合仿真。仿真结果表明,该飞轮转子动力学模型能够快速起浮响应并稳定悬浮,误差符合精度要求,验证了模型的有效性,可为研究车载飞轮电池转子动态特性提供理论依据和模型参考。 相似文献
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In rhythmically growing woody species such as common oak (Quercus robur L.), stem growth is discontinuous and a bud forms at regular intervals at the shoot apex. These buds are composed of different types of leaves: laminate, aborted lamina and scale. The change in heteroblastic leaf shape from laminate to aborted lamina leaves is regarded as one of the events marking shoot growth arrest. To better understand the determinism of heteroblastic leaf shape change and thus, of rhythmicity, we studied morphogenetic events during the early days of the second flush of growth in oak, as well as changes in sucrose metabolism and abscisic acid (ABA) concentrations in control plants expressing the heteroblastic leaf shape change and in defoliated plants showing no heteroblastic leaf shape change and producing only laminate leaves. In control plants, the leaf shape change was underway on Day 5 of the second flush with the differentiation of the first two aborted lamina leaves. Sucrose concentration in the apices of control plants decreased between Days 3 and 5 during differentiation of the aborted lamina leaves. An inverse pattern was observed in defoliated plants, suggesting that sucrose acts as a signal triggering heteroblastic leaf shape changes. During the same period, acid cell wall invertase activity was high in young stem and laminate leaves of control plants, whereas the activity remained constant and low in the apices. If the laminate leaves were removed, the increase in apical sucrose concentration was proportionally higher than the decrease in apical acid vacuolar invertase activity, suggesting that, in the absence of young leaves, sucrose is imported to the apex. The sucrose concentration in the apex is therefore likely to be affected by trophic competition with the expanding laminate leaves. The decrease in apex sucrose concentration may be one of the mechanisms driving heteroblastic leaf shape change. Differentiation of aborted lamina leaves was followed by a decrease in the organogenic activity of the shoot apical meristem (SAM) between Days 7 and 9. High concentrations of ABA are associated with differentiation of aborted lamina and scale leaves and with low SAM organogenic activity. Shoot apical meristem organogenic activity remained high and ABA concentration in the apex remained low in defoliated plants producing only photosynthetic leaves. These results suggest that (1) ABA is involved in the gradual conversion of embryonic leaves to abnormal leaves, thereby regulating heteroblastic leaf shape changes and (2) changes in ABA concentration influence the intensity of SAM organogenic activity. Heteroblastic development and therefore rhythmic growth could be the result of competition between apices and laminate leaves, with competition first involving sucrose and thereafter ABA. 相似文献
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为了给油茶林施肥管理提供科学依据,通过不同模式施肥,对油茶叶片生长和叶片养分含量进行研究,探讨油茶叶片各生长指标与叶片养分含量之间的关系。结果表明:各模式对油茶叶片生长指标和叶片养分含量均有显著促进作用,叶形指数与其它指标有负显著相关性,比叶重与其它指标间有正显著相关性,叶片养分中N、P、K的含量与其它指标间均存在显著相关性,说明施肥模式与叶片生长间关系密切。各模式对油茶叶片的肥效作用由大到小排列依次为:M5、M4、M2、M3、M1、M0、CK。 相似文献
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为给进一步开展野杏种质资源多样性及亲缘关系研究提供参考,选取新疆霍城大西沟不同区域分布的野杏单株,利用DPS7.05数据处理软件对枝叶形态性状指标进行聚类分析和主成分分析,探讨新疆野杏株间枝叶形态特征差异。聚类分析结果显示,系统聚类将62个野杏单株的15个枝叶形态性状分为4大类;主成分分析结果表明,前7个主成分的累计贡献率约为89.04%,影响较大的因子是叶片长度、叶片宽度、长宽比、叶柄长、叶面积、叶背绒毛、叶缘形态、新梢长度和粗度等。数量分类结果能反映出各单株间的遗传差异,大西沟野杏具有丰富的多样性,通过主成分分析选出了野杏分类的主要性状。通过聚类分析能清楚反映出所选野杏单株间的亲缘关系。 相似文献
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Leaves are of fundamental importance to plants,representing their facility to generate power and are the sensing units of plants towards the environment.An attempt was made to characterize and compare the variations of leaf morphology of various Populus deltoides Bartr.clones by studying the winter buds and other leaf parameters of fully developed leaves.To achieve these objectives,forty-three exotic and indigenous clones of P.deltoides Bartr.were evaluated for different parameters.On the basis of various morphological characteristics the results reveal that each clone has a distinct color pattern of leaves.Different colors observed in these clones varied from light green through green to dark green.Two distinct lengths of the leaf apex were found,i.e.,short and long; as well both acuminate and acute apex types were found.Erratic distribution of serration of leaves was also found.In this study,the morphological traits of leaves provided discriminatory grounds for separating various populations of P.deltoides Bartr.clones.Winter bud studies indicate that different clones vary considerably with regard to shape,color,shape of leaf scars and exudation. 相似文献
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选取磴口、民勤唐古特白刺,敦煌东湖附近洪积扇中部、底部生长的泡泡刺为研究对象,通过叶片扫描与Image-Pro Plus6.0图像处理软件分析获得叶片形态参数(长、宽、周长和面积),应用同位素分析获得叶片δ13C值。结果表明:随着水分有效性的增加,白刺叶片面积具有增加趋势,叶片面积在增加过程中,叶片长、宽增幅具有非同步性;相同叶片宽度,生长于水分条件较好地区的唐古特白刺和泡泡刺叶片更长。虽然磴口、民勤及敦煌东湖附近洪积扇中部、底部水分环境存在较大的差异,但生长于这些区域的唐古特白刺及泡泡刺叶片δ13C值的差异不显著(P>0.05)。叶片周长/面积比是连接叶片形态变化与植物水分生理的重要因子;白刺叶面积增加过程中,叶片长度的优先增加有利于减缓周长/面积比的下降速率,从而使白刺保持较高的水分利用效率。 相似文献
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The spatial pattern of the crown spread ofQuercus glauca in a hardwood community was investigated in order to consider the effect of the patterns on its survival in a secondary hardwood
community. The shape of a crown was defined by the spatial spread of the leaves (PCM crown), and by the spread of their branches
(elliptic cylinder crown). The stem volume growth rate of a tree was strongly correlated with the corresponding total leaf
area, which was then significantly correlated with the defined crown volume. This indicated that the stem volume growth depended
on the crown volume as well as the total leaf area. An increase in leaf area was largely attained by the spatial volume of
the crown, not by an increase in the leaf area density. The leaves inside the crown began to spread horizontally relative
to the crown size as the total leaf area and tree size increased. On the other hand, for the crowns representing the branch
spread, the crown shape (crown width/depth ratio) did not differ by internal leaf area and tree size. Such a spatial pattern
was likely to be adaptive for a species that dominates at a mid-stage of secondary sere. 相似文献