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西昌车务段运能现状分析及扩能策略研究
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作者 刘俊杰 《河北交通职业技术学院学报》 2010年第4期61-63,共3页
通过对西昌车务段运力、装卸车能力、日均车流量的分析,得出西昌车务段目前运输能力已经相当紧张,部分线路已经超过图定能力,必须进行扩能改造才能满足日益增长的运输需求。提出了从管理提效和设备升级两方面来提高运输能力的扩能策略,... 通过对西昌车务段运力、装卸车能力、日均车流量的分析,得出西昌车务段目前运输能力已经相当紧张,部分线路已经超过图定能力,必须进行扩能改造才能满足日益增长的运输需求。提出了从管理提效和设备升级两方面来提高运输能力的扩能策略,实践证明该策略扩能效果显著。 展开更多
关键词 西昌车务段 运力分析 日均车流 装卸能力 扩能策略
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Sex-specific strategies of resource utilization and determining mechanisms of Hippophae rhamnoides in response to community succession
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作者 Baoli Fan Pengfei Gao +3 位作者 Tingting Tian Nana Ding Yongkuan Wan Xianhui Zhou 《Journal of Plant Ecology》 SCIE CSCD 2024年第4期114-130,共17页
The dioecious plant,Hippophae rhamnoides,is a pioneer species in community succession on the Qinghai-Tibet Plateau(QTP),plays great roles in various ecosystem services.However,the males and females of the species diff... The dioecious plant,Hippophae rhamnoides,is a pioneer species in community succession on the Qinghai-Tibet Plateau(QTP),plays great roles in various ecosystem services.However,the males and females of the species differ both in their morphology and physiology,resulting in a change in the ratio of male to female plants depending on the environment.To further explore the functional traits critical to this sex-based distinctive response in the alpine grassland,we have surveyed the sex ratios,measured their photosynthetic parameters,height,leaf area and biomass allocation.The results showed that(i)The males had higher Pn,light saturation point,apparent quantum efficiency,A_(max) and lower water-use efficiency(WUE),which exhibited higher utilization efficiency or tolerance to strong light,while the females indicated higher utilization efficiency for low light and water.And it showed sex-specific biomass allocation patterns.(ii)H.rhamnoides populations across the successional stages all showed a male-biased sexual allocation,which was closely related to sex-specific WUE,Pn,root biomass/total biomass and root-crown ratio.(iii)The leaf traits of H.rhamnoides changed from higher N_(area),P_(area) and leaf mass per area in the early and late to lower in the middle,which meant they moved their growth strategy from resource rapid acquisition to conservation as the succession progressed.(iv)The increasing soil total phosphorus mostly contributed to regulating the sex bias of populations and variations of traits during the succession.The results are vital for the management of grassland degradation and restoration due to shrub encroachment on the QTP. 展开更多
关键词 DIOECIOUS sex ratio shrub encroachment functional traits physiological and ecological strategies
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