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地形因素对红松结实数量的影响
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作者 李丙金 赵玉芹 《黑龙江林业》 2003年第7期19-19,共1页
关键词 地形因素 红松 结实数量 生物学 生态学特征 气候条件
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贝加尔针茅草原围栏封育和自由放牧条件下植物结实数量的研究 被引量:33
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作者 王明玖 李青丰 青秀玲 《中国草地》 CSCD 2001年第6期21-26,共6页
在两个不同的降水年份 ,于内蒙古锡林郭勒草原东部的贝加尔针茅草原上 ,采用收获单位面积草原群落植物全部种子的办法 ,对比观察了连续自由放牧或阶段性放牧与围栏封育条件下植物结实量及结实植物种类和出现率的差异 ,同时观察了围栏内... 在两个不同的降水年份 ,于内蒙古锡林郭勒草原东部的贝加尔针茅草原上 ,采用收获单位面积草原群落植物全部种子的办法 ,对比观察了连续自由放牧或阶段性放牧与围栏封育条件下植物结实量及结实植物种类和出现率的差异 ,同时观察了围栏内、外贝加尔针茅种子生产数和狼毒单花序成花数的差异。结果表明 ,植物结实受放牧采食和降水条件的共同影响。同围栏封育相比 ,连续自由放牧不利于植物结实。而春季放牧夏秋休闲的阶段性放牧可以使植物结实性迅速恢复 ,这种影响对部分植物来说 ,甚至超越于降水的影响。 展开更多
关键词 贝加尔针茅草原 植物 结实数量 围栏封育 自由放牧
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灌水对樟子松种子园母树生长及结实的影响 被引量:2
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作者 白昀 刘小军 《陕西林业科技》 2009年第4期31-34,共4页
根据榆林市樟子松种子园建立以来的水分管理档案和抽样调查数据,分析了灌溉对母树生长及结实的影响。结果表明:灌溉能明显促进母树营养生长,也可在一定程度上提高结实数量。回归分析结果进一步表明降水量以及水热平衡关系是影响母树生... 根据榆林市樟子松种子园建立以来的水分管理档案和抽样调查数据,分析了灌溉对母树生长及结实的影响。结果表明:灌溉能明显促进母树营养生长,也可在一定程度上提高结实数量。回归分析结果进一步表明降水量以及水热平衡关系是影响母树生长的主导因子。 展开更多
关键词 樟子松 无性系 营养生长 结实数量 人工灌溉 水热状况
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中阿向冠军家乡赠肥 承诺质量始终如一
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作者 徐骞 《中国农资》 2013年第22期18-18,共1页
从许昌到平顶山的高速公路两侧,大片金黄色的小麦等着收割,由于近日的连续降雨,收割时间有所延后,而正是因为小麦收割的延迟,我们才有机会发现田间的问题。一路上,我们经常发现同一个地块的两片小麦长势迥异,部分小麦株高不足30c... 从许昌到平顶山的高速公路两侧,大片金黄色的小麦等着收割,由于近日的连续降雨,收割时间有所延后,而正是因为小麦收割的延迟,我们才有机会发现田间的问题。一路上,我们经常发现同一个地块的两片小麦长势迥异,部分小麦株高不足30cm,结实数量也低于正常水平。 展开更多
关键词 小麦株高 质量 收割时间 公路两侧 结实数量 平顶山 金黄色 降雨
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A Study of Fructification Quantitative Characteristics of Spartina alterniflora Lossel in Mangroves 被引量:7
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作者 覃盈盈 梁士楚 《Agricultural Science & Technology》 CAS 2009年第1期101-104,共4页
[Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflo... [Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflora in Mangroves conservation zone located at Hepu of Guangxi being taken as experimental material, its morphological and quantitative characteristics, as well as the weight of 100 full seeds at maturity stage in three different growth conditions( clay, loam and sand) were studied. [ Results] The results showed that Spartina alterniflora had the best growth pattern in the loam. The morphological factors of fructification of S. altemiflora grown in sand were larger then in others. In the three growth conditions the order of quantitative characteristics of fructification of S. alterniflora was clay 〉 sand 〉 loam and the seeds in spikelet at top position were more maturity than those at the button position. [ Conclusion] In good condition, the Spartina altemiflora growth was vigor but the ratio of seed-setting was low. 展开更多
关键词 Spartina altemiflora Different habitat FRUCTIFICATION Quantitative characteristics
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Influence of A Hyperons ^1S0 Superfluidity on the Direct Urca Processes with Hyperons 被引量:1
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作者 许妍 刘广洲 +2 位作者 吴姚睿 王红岩 张峰 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第9期521-524,共4页
In the framework of the relativistic mean field theory (RMFT), the relativistic energy losses of the direct Urea processes with hyperons (Y-DURCA ) for reactions A → p + e + υe and ≡^-→ A+e+υe are studied... In the framework of the relativistic mean field theory (RMFT), the relativistic energy losses of the direct Urea processes with hyperons (Y-DURCA ) for reactions A → p + e + υe and ≡^-→ A+e+υe are studied in neutron stars. We calculate the energy gap of A hyperons and investigate the effects of the ^1S0 superfluidity (SF) of A hyperons on the Y-DURCA processes. The calculated results are in line with the recent experimental data △ BAA ~ 1.01 ±0.20-0.11^+0.18 MeV. The results indicate that the ^1S0 SF of A hyperons exists in most density ranges of happening the two reactions. The theoretical cooling curves are in agreement with observation data. 展开更多
关键词 hyperons superfluidity direct Urca processes with hyperons neutron star
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Lagrangian view of time irreversibility of fluid turbulence
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作者 HaiTao Xu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2016年第1期7-15,共9页
A turbulent flow is maintained by an external supply of kinetic gradients. The scale at which energy is supplied greatly differs energy, which is eventually dissipated into heat at steep velocity from the scale at whi... A turbulent flow is maintained by an external supply of kinetic gradients. The scale at which energy is supplied greatly differs energy, which is eventually dissipated into heat at steep velocity from the scale at which energy is dissipated, the more so as the turbulent intensity (the Reynolds number) is larger. The resulting energy flux over the range of scales, intermediate between energy injection and dissipation, acts as a source of time irreversibility. As it is now possible to follow accurately fluid particles in a turbulent flow field, both from laboratory experiments and from numerical simulations, a natural question arises: how do we detect time irreversibility from these Lagrangian data? Here we discuss recent results concerning this problem. For Lagrangian statistics involving more than one fluid particle, the distance between fluid particles introduces an intrinsic length scale into the problem. The evolution of quantities dependent on the relative motion between these fluid particles, including the kinetic energy in the relative motion, or the configuration of an initially isotropic structure can be related to the equal-time correlation functions of the velocity field, and is therefore sensitive to the energy flux through scales, hence to the irreversibility of the flow. In contrast, for single- particle Lagrangian statistics, the most often studied velocity structure functions cannot distinguish the "arrow of time". Recent observations from experimental and numerical simulation data, however, show that the change of kinetic energy following the particle motion, is sensitive to time-reversal. We end the survey with a brief discussion of the implication of this line of work. 展开更多
关键词 fluid turbulence time irreversibility energy cascade Lagrangian description
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