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以涿廊高速公路为例,利用1999~2010年的年均降水量、年均气温、日照时间、年积温数据和杨树、柳树、紫穗槐、爬山虎、紫花苜蓿的生长条件,基于主成分分析和层次分析法建立高等级公路边坡植被适应性评价模型。结果表明:在一定区域范围内,利用主成份和层次分析法,构建的高等级公路边坡护坡植被适应性评价模型是可行的,并为植被适应性评价探索了一条新方法和途径。 相似文献
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豚草传播特性的初步观察 总被引:6,自引:0,他引:6
豚草具有很强的生态适应性,其种子萌发受温度的制约明显,豚草从侵入某一地区到进入稳定阶段以前,其群聚度往往与侵入时间的长短呈正相关,当外界阻力达到或接近足够阻止豚草种群在该地区的继续扩展时,此种群就进入了稳定阶段。建议采取综合防除措施。 相似文献
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福建绿竹地理种源的生长适应性 总被引:8,自引:0,他引:8
郑维鹏 《南京林业大学学报(自然科学版)》2003,27(5):51-54
以不同的选择指标,在不同的试验点选择与当地环境相适宜的优良种源,结果表明:种源问的差异随着造林时间的延长逐渐增强;标准枝的叶片数各处理间的差异显性较其它性状大。试验期间永安试验点各种源笋产量较稳定,福安和永安种源在永安地区生长良好,而适宜在龙海大力推广的是漳州和永安种源。 相似文献
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C. Bertoluzza V. Doldi J. Jimnez S. Montes 《International Journal of Approximate Reasoning》2008,48(2):481-498
Measuring the degree of non-adaptability of a partition to a criterion, represented by a reference partition, is an essential step in pseudo-questionnaires theory. In this work we characterize axiomatically the measure of non-adaptability in a general context. We base it on pre-orders on the set of all the possible experiences (complete or incomplete partitions). The construction of this measure is crucial for practical applications. It can be done in a natural way starting from the atoms of the partitions and constructing the non-adaptability measure by a process of successive aggregations made by suitable aggregation operators. 相似文献
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Based on neurophysiological evidence, theoretical studies have shown that walking can be generated by mutual entrainment of oscillations of a central pattern generator (CPG) and a body. However, it has also been shown that the time delay in the sensorimotor loop destabilizes mutual entrainment, and results in the failure to walk. Recently, it has been reported that if (a) the neuron model used to construct the CPG is replaced by physiologically faithful neuron model (Bonhoeffer–Van der Pol type) and (b) the mechanical impedance of the body (muscle viscoelasticity) is controlled depending on the angle between two legs, the phase relationship between CPG activity and body motion could be flexibly locked according to the loop delay and, therefore, mutual entrainment can be stabilized. That is, locomotor control adaptive to the loop delay can emerge from the coupling between CPG and body. Here, we call this mechanism flexible-phase locking. In this paper, we construct a system of coupled oscillators as a simplified model of a walking system to theoretically investigate the mechanism of flexible-phase locking, and to analyze the simplified model. The analysis suggests that the following are required as the essential mechanism: (i) an asymptotically stable limit cycle of the coupling system of CPG and body and (ii) a sign difference between afferent and efferent coupling coefficients. 相似文献
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针对古书院矿151306工作面易于积聚能量的坚硬顶板地质条件,垮落来压时会对支架形成冲击载荷,支架需具有良好的适应性才能保证工作面安全生产.按照液压支架的选型原则进行理论计算和参数验证,最终确定选用ZZ8800/14/26D型液压支架.采用全程矿压观测方法,在151306工作面布设测线,观测支架初支撑力、末支撑力及时间平均工作阻力.结果表明,在整个工作面回采过程中,ZZ8800/14/26D型液压支架运行状况良好,能够满足支撑顶板的要求.研究成果对坚硬顶板条件下液压支架选型与适应性分析具有指导意义。 相似文献
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本文首先定性描述了汽车驾驶员必须具备的身体素质,然后用多元统计分析方法对测试结果进行统计分析.文中提出的方法可供制定汽车驾驶员职业适应性标准参考. 相似文献
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金跃峰 《山西师范大学学报:自然科学版》2000,14(1):86-90
“马家军”的成功已是世界田坛当今最热门的话题之一。专家都在研究、探索“马家军”训练的真缔,以求移植于其他田径项目,本文力求从运动生理学角度对马氏训练方法作初步探讨。 相似文献