查询词典 harvesting

Key words: biomathematics; optimal harvesting problem; stochastic differential equation; mutualism model; harvesting cost

关键 词：生物数学；最优捕获问题；随机微分方程；互惠模型；捕获费用

A predator model with refuge and toxicity is studied. By constructing a suitable Dulac function, it is shown that there is no limit cycle in the first quadrant, thus the globally stability of the equilibrium is proved. Further more, the paper analyzes the influence of refuge, toxicity and harvesting. It is amazing that ① if the death rate of predator is big or the harvesting effort is big, the existence of the predator is unrelated with refuge; if the death rate of predator and the harvesting effort are small, and the refuge is small enough, the population of both species is increased as the increase of refuge;② if d2=0, the increase of d1 has no influence on the prey population, while the population of predator is decreased.

研究一类有避难所、毒素作用和外界捕获影响的捕食系统，通过构造恰当的Dulac函数，证明系统在第一象限没有极限环，从而证明了平衡点的全局稳定性；分析了避难所、毒素、捕获作用对该系统最终种群数量的影响，发现：①当捕食者的死亡率大或其被捕获得多时，两种群的绝灭与避难所的存在无关；当捕食者的死亡率小、被捕获得多且避难所足够小时，随着食饵避难所的增加，捕食者种群数量也随之增加；②当毒素d2=0时，毒素d1的增加对食饵种群最终数量没有影响，而使捕食者种群数量下降。

Abstract］ Objective To compare the indican content of folium isatidis in different origin and different harvesting period.Methods By HPLC on different areas, different harvesting times,determined indican.

目的 对比不同产地及不同采收时期青叶中吲哚苷含量方法采用HPLC法对不同产地、不同采收时期的大青叶中的吲哚苷进行了测定。

This study deals with precipitation fluctuations in the transitional zone between the arid and semiarid regions of northwest China from the 1950s to the 1990s,discusses spatial variation of 250 mm isohyet during the dry years and wet years; and systematically studies rainfall harvesting system relative to runoff inducing catchments, water storage and highly efficient utilization and evaluates the influence of rainwater harvesting on regional development and environment conservation.

分析了干旱半干旱区过渡带降水的时空变异性，确定了250 mm降水量线在丰枯年份的空间摆动幅度。

Then analyze the local stability of the model. The optimal harvesting policy for harvesting the prey species is studied.

然后分析了模型的局部稳定性，得到了对食饵进行捕获的最优捕获策略。

Presently, the main harvesting of Arundo donaxl is traditional manual ways, the working conditions are bad, the harvesting efficiency is low and the cost is high. To harvest Arundo donaxl on schedule and maintaining the quality and quantity is key to ensure the bumper harvest and yield, the croppers income and the timely supply as industrial material, the mechanization harvest has been urgent for the industrialization of Arundo donaxl planting and timely harvest.

然而，目前芦竹的收割仍主要采用传统的手工方式收割，劳动环境艰苦，收割效率低且成本高，按期保质保量收割芦竹是芦竹种植场丰产丰收，实现种植场农民增收和保证其作为工业原料来源的关键。

The result showed that the volume, dry weight and total sugar content of root gradually reduced with the harvest frequency, but the reductive sugar content in root increased. While the harvesting frequency was two times per year, the volume and dry weight of alfalfa root showed an decreasing at beginning and then increasing when the first harvesting was at different growth stages and the lowest values were at flowering period however, it was not significant for brome.

结果表明：随刈割次数增加，两种牧草根体积、根干重和根部总含糖量逐渐减小，而根系还原糖含量呈逐渐增加的趋势；在年刈割两次，首次刈割分别在不同生育时期试验处理中，苜蓿根体积和干重呈先减后增趋势，首次刈割在盛花期根体积和干物质含量均最低，而无芒雀麦变化不明显。

The effect of harvesting height on the grass yield and quality of two varieties of Lolium multiflorum was studied and the result showed that the different harvesting height greatly affected the fresh yield, dry mater yield, quality and growth characteristics.

多花黑麦草Lolium multifolium具有很强的再生性和耐刈性，为了确定最佳的刈割利用方式，在有限的耕地中获得较高的产量和效益，采用小区试验的方法，研究了不同刈割高度对多花黑麦草特高和杰威产草量和品质的影响。

Percent of 〓C photosynthesized into plant at early harvesting redistributed to fruit at profuse harvesting.

始采期固定的〓C到盛采期仍有1/4分配于果实中，其对果实的贡献至少可持续一个月。

The harvesting cost by hand is 6 times higher than that by machine harvester, so machine harvesting of sugarcane is a vital factor to reduce the production and improve international competitiveness. As an important composition part of sugarcane harvester, the mechanism capability influence windrowing quality and working efficiency directly.

作为甘蔗收获机的一个重要组成部件，夹持输送装置性能好坏直接影响到甘蔗输送铺放质量和整机工作效率，因此研究夹持输送装置的工作机理，探索不同运动参数和结构参数下的夹持输送质量、铺放质量和功耗大小，为夹持输送装置和甘蔗收获机械的设计提供依据，具有重要的实用价值。

This is not an ordinary box, which is used as a background picture of the dialog box, very pretty.

详细说明：这可不是一个一般的对话框，它是用图片作为背景的对话框，非常好看。

Conceal me what I am,and be my aid for such disguise as haply shall become the form of my intent.

遮掩我的身份，帮助我，我的面具将成为我的目的。