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Analysis on the daily courses of water potential of nine woody species from Cerrado vegetation during wet season 被引量:5
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作者 张文辉 马瑞萍 《Journal of Forestry Research》 CAS CSCD 2000年第1期7-12,共6页
The water potential (Ψ) daily courses of 9 woody species from Cerrado vegetation in different weather conditions during wet season were observed and analyzed. The adjusting strategies of 9 species could be divided in... The water potential (Ψ) daily courses of 9 woody species from Cerrado vegetation in different weather conditions during wet season were observed and analyzed. The adjusting strategies of 9 species could be divided into 3 groups according to Cluster Analysis and based on the data observed on the January 18, March 20 and April 6. The Ψ values of the first group, which included 2 species, were maintained at the higher level consistently. The Ψ values of the second group, which included 5 species, were intermediate level. The Ψ values of the third group, which included 2 species, were kept in the lower level. The Ψ values of all species always kept pace with the weather condition, especially water condition. During the clear day only one Ψ value peak for all species occurred at midday (12∶30–13∶30). When the overcast or raining occurred for a short period, the fluctuation of Ψ values would appear after about 15–30 min responding to the change of weather condition. Even in the same group under the same external circumstance, there was a clear variation of the leaf Ψ values among different species, which showed that the strategy diversity for plant to balance water relation. From January to April, the Ψ values of 9 species reduced in response to the drought condition. The species with the lower values of water saturation deficiency at turgid loss point (W sdtlp) the osmotic potential at saturation (πsat), the osmotic potential at turgid lose point (πtip) or lower predawn water potential (Ψpd) usually had the lower Ψ values at midday. The mechanism of water balance controlled by many systems has been assumed. 展开更多
关键词 Wet season Water balance strategy Osmotic potential Water potential Woody species
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Service Scheduling Based on Edge Computing for Power Distribution IoT 被引量:2
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作者 Zhu Liu Xuesong Qiu +2 位作者 Shuai Zhang Siyang Deng Guangyi Liu 《Computers, Materials & Continua》 SCIE EI 2020年第3期1351-1364,共14页
With the growing amounts of multi-micro grids,electric vehicles,smart home,smart cities connected to the Power Distribution Internet of Things(PD-IoT)system,greater computing resource and communication bandwidth are r... With the growing amounts of multi-micro grids,electric vehicles,smart home,smart cities connected to the Power Distribution Internet of Things(PD-IoT)system,greater computing resource and communication bandwidth are required for power distribution.It probably leads to extreme service delay and data congestion when a large number of data and business occur in emergence.This paper presents a service scheduling method based on edge computing to balance the business load of PD-IoT.The architecture,components and functional requirements of the PD-IoT with edge computing platform are proposed.Then,the structure of the service scheduling system is presented.Further,a novel load balancing strategy and ant colony algorithm are investigated in the service scheduling method.The validity of the method is evaluated by simulation tests.Results indicate that the mean load balancing ratio is reduced by 99.16%and the optimized offloading links can be acquired within 1.8 iterations.Computing load of the nodes in edge computing platform can be effectively balanced through the service scheduling. 展开更多
关键词 PD-IoT edge computing service scheduling load balancing strategy ant colony algorithm
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Untethered quadrupedal hopping and bounding on a trampoline
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作者 Boxing WANG Chunlin ZHOU +3 位作者 Ziheng DUAN Qichao ZHU Jun WU Rong XIONG 《Frontiers of Mechanical Engineering》 SCIE CSCD 2020年第2期181-192,共12页
For quadruped robots with springy legs,a successful jump usually requires both suitable elastic parts and well-designed control algorithms.However,these two problems are mutually restricted and hard to solve at the sa... For quadruped robots with springy legs,a successful jump usually requires both suitable elastic parts and well-designed control algorithms.However,these two problems are mutually restricted and hard to solve at the same time.In this study,we attempt to solve the problem of controller design with the help of a robot without any elastic mounted parts,in which the untethered robot is made to jump on a trampoline.The differences between jumping on hard surfaces with springy legs and jumping on springy surfaces with rigid legs are briefly discussed.An intuitive control law is proposed to balance foot contact forces;in this manner,excessive pitch oscillation during hopping or bounding can be avoided.Hopping height is controlled by tuning the time delay of the leg stretch.Together with other motion generators based on kinematic law,the robot can perform translational and rotational movements while hopping or bounding on the trampoline.Experiments are conducted to validate the effectiveness of the proposed control framework. 展开更多
关键词 hopping and bounding gait compliant mechanism compliant contact balance control strategy legged locomotion control quadruped robot
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Study on the Current US Strategic Adjustment in the Middle East
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作者 WANG Bo 《Asian Journal of Middle Eastern and Islamic Studies》 2013年第1期82-99,共18页
After the end of the Cold War,the US pushed its hegemonic strategy fully in the Middle East depending on its position as the only super power in the world and tried to establish its hegemony in the Middle East with mi... After the end of the Cold War,the US pushed its hegemonic strategy fully in the Middle East depending on its position as the only super power in the world and tried to establish its hegemony in the Middle East with military interference and political reconstruction.However,the Iraq war that the US launched in 2003 has not only consumed much of its own strength but also caused many conditions that the US cannot deal with,such as the increase of the Iranian theocratic power,the expanding of terrorism,and the spread of Islamic people’s uprisings.Faced with the combination and the development of anti-US forces,the US has to adjust its strategy and replace military hegemony with an offshore balancing strategy.The offshore balancing strategy stresses that the US should transfer the responsibility of maintaining the regional security to the allies in this region and encourages them to form a balance to contain the hostile Islamic forces.At the same time,the US should withdraw its military force from the Middle East region.It will be helpful to avoid the hostile Islamic forces to prompt the anti-US sentiment and to maintain hegemony for the US in the region with a more cover way. 展开更多
关键词 US Middle East strategy Adjustment Offshore Balancing strategy
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