麦冬是一种生长在浙江的中草药,通常被种植在畦装的土地中。在收获麦冬时如果牵引的拖拉机不小心落入畦沟中,则三点悬挂的麦冬收获机的杆件易被拉断。为解决这一问题,本文研发出了一种自动水平控制系统,它由总控制器、电子控制单元(elec...麦冬是一种生长在浙江的中草药,通常被种植在畦装的土地中。在收获麦冬时如果牵引的拖拉机不小心落入畦沟中,则三点悬挂的麦冬收获机的杆件易被拉断。为解决这一问题,本文研发出了一种自动水平控制系统,它由总控制器、电子控制单元(electronic control unit, ECU)、双天线GPS接收机、拉绳传感器、油缸和液压阀组成,可使收获机一直处于水平姿态。总控制器先后采集到拖拉机的横滚角、油缸的位移量,估算出收获机的横滚角。采用比例微分(proportion integration differentiation, PID)控制算法产生液压阀的控制量。在麦冬田中的试验结果显示,左、右点之间的高程差是1.04 cm,标准差是2.39 cm,收获机可一直保持水平姿态,其构件没有再次断裂。展开更多
Mechanized construction of micro-catchments for water harvesting （WH） was successfully tested in the Badia （dry rangeland） areas in Syria and Jordan, using the ＂Vallerani＂ plow, model Delfino （50 MI/CM）, manuf...Mechanized construction of micro-catchments for water harvesting （WH） was successfully tested in the Badia （dry rangeland） areas in Syria and Jordan, using the ＂Vallerani＂ plow, model Delfino （50 MI/CM）, manufactured by Nardi, Italy. The plow was able to construct intermittent and continuous contour ridges, and could potentially be used to rehabilitate degraded rangelands. However, one major issue for large-scale implementation is the high cost and time required to manually identify contours for the plow to follow. Most existing auto-guiding systems, as usually used in road construction and agricultural land leveling, were expensive or impractical. The objective, therefore, was to add, adapt, and evaluate an auto-guiding system to enable a tractor to follow contours without demarcation through conventional surveying. A low-cost Contour Laser Guiding （CLG） system, with specifications that suit the contour ridging in undulating topographic conditions of dry rangelands, was chosen, adapted, mounted, and tested, under actual field conditions. The system consisted mainly of a portable laser transmitter and a tractor-mounted receiver, connected to a guidance display panel. The system was field-tested on 95 ha of land where the system capacity was determined under different terrains, slopes （1-8%）, and ridge spacings （4-12 m）. The easy adaptation and implementation of the CLG to the ＂Vallerani＂ unit tripled the system capacity, improved efficiency and precision, and substantially reduced the cost of constructing micro-catchments for WH. The system is recommended for large-scale rangeland rehabilitation projects in the dry areas, not only in West Asia, but worldwide.展开更多
In the framework of D6rnyei＇s L2 Motivational Self System （hereafter abbreviated as L2MSS）, this paper makes an empirical survey among learners of English in China, investigating the parameters of the three interna...In the framework of D6rnyei＇s L2 Motivational Self System （hereafter abbreviated as L2MSS）, this paper makes an empirical survey among learners of English in China, investigating the parameters of the three internal components of L2MSS among learners of various L2 proficiency levels. It is found that the strongest predictor among the three internal components of L2MSS contributing to the L2 Learning Motivation is closely related to learners＇ L2 proficiency levels. For lower-level L2 learners, the strongest predictor of L2 Learning Motivation is Second Language Learning Experience （hereafter abbreviated as SLLE）, while for higher-level L2 learners, the strongest predictor is their Ideal L2 Self. Furthermore, the overall picture of the parameters of the three internal components of L2MSS across various groups of L2 proficiency levels shows a regular pattern. That is, with the increase of L2 proficiency, the self dimension （Ideal 1.2 Self and Ought-to L2 Self, especially the former） plays an increasingly important role in its contribution to L2 Learning Motivation while the SLLE plays a decreasingly important role in the contribution to L2 Learning Motivation.展开更多
基金Project supported by the Key Agricultural Project of Ningbo Science and Technology Bureau,Zhejiang(2016C10023)Key Agricultural Project in 2017 of Yinzhou Science and Technology Bureau,Zhejiang.
文摘麦冬是一种生长在浙江的中草药,通常被种植在畦装的土地中。在收获麦冬时如果牵引的拖拉机不小心落入畦沟中,则三点悬挂的麦冬收获机的杆件易被拉断。为解决这一问题,本文研发出了一种自动水平控制系统,它由总控制器、电子控制单元(electronic control unit, ECU)、双天线GPS接收机、拉绳传感器、油缸和液压阀组成,可使收获机一直处于水平姿态。总控制器先后采集到拖拉机的横滚角、油缸的位移量,估算出收获机的横滚角。采用比例微分(proportion integration differentiation, PID)控制算法产生液压阀的控制量。在麦冬田中的试验结果显示,左、右点之间的高程差是1.04 cm,标准差是2.39 cm,收获机可一直保持水平姿态,其构件没有再次断裂。
文摘Mechanized construction of micro-catchments for water harvesting （WH） was successfully tested in the Badia （dry rangeland） areas in Syria and Jordan, using the ＂Vallerani＂ plow, model Delfino （50 MI/CM）, manufactured by Nardi, Italy. The plow was able to construct intermittent and continuous contour ridges, and could potentially be used to rehabilitate degraded rangelands. However, one major issue for large-scale implementation is the high cost and time required to manually identify contours for the plow to follow. Most existing auto-guiding systems, as usually used in road construction and agricultural land leveling, were expensive or impractical. The objective, therefore, was to add, adapt, and evaluate an auto-guiding system to enable a tractor to follow contours without demarcation through conventional surveying. A low-cost Contour Laser Guiding （CLG） system, with specifications that suit the contour ridging in undulating topographic conditions of dry rangelands, was chosen, adapted, mounted, and tested, under actual field conditions. The system consisted mainly of a portable laser transmitter and a tractor-mounted receiver, connected to a guidance display panel. The system was field-tested on 95 ha of land where the system capacity was determined under different terrains, slopes （1-8%）, and ridge spacings （4-12 m）. The easy adaptation and implementation of the CLG to the ＂Vallerani＂ unit tripled the system capacity, improved efficiency and precision, and substantially reduced the cost of constructing micro-catchments for WH. The system is recommended for large-scale rangeland rehabilitation projects in the dry areas, not only in West Asia, but worldwide.
基金supported by the Humanity and Social Sciences Planning Fund Sponsored by Chinese Ministry of Education(Grant No.10YJAZH048)
文摘In the framework of D6rnyei＇s L2 Motivational Self System （hereafter abbreviated as L2MSS）, this paper makes an empirical survey among learners of English in China, investigating the parameters of the three internal components of L2MSS among learners of various L2 proficiency levels. It is found that the strongest predictor among the three internal components of L2MSS contributing to the L2 Learning Motivation is closely related to learners＇ L2 proficiency levels. For lower-level L2 learners, the strongest predictor of L2 Learning Motivation is Second Language Learning Experience （hereafter abbreviated as SLLE）, while for higher-level L2 learners, the strongest predictor is their Ideal L2 Self. Furthermore, the overall picture of the parameters of the three internal components of L2MSS across various groups of L2 proficiency levels shows a regular pattern. That is, with the increase of L2 proficiency, the self dimension （Ideal 1.2 Self and Ought-to L2 Self, especially the former） plays an increasingly important role in its contribution to L2 Learning Motivation while the SLLE plays a decreasingly important role in the contribution to L2 Learning Motivation.
