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棉田残膜留量及棉秆带出残膜量的跟踪测定
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作者 刘忠元 《新疆农垦科技》 1990年第6期20-21,共2页
一、调查目的 148团近年回收棉田残膜的一个重要方式,是用铲秆机将残膜随棉秆带出。为了弄清棉田残膜及棉秆带出田外残膜的具体数量,以便进一步开展残膜回收,减轻或消灭残膜污染提供理论依据。 二、调查方法 选取连作两年和麦棉轮作的... 一、调查目的 148团近年回收棉田残膜的一个重要方式,是用铲秆机将残膜随棉秆带出。为了弄清棉田残膜及棉秆带出田外残膜的具体数量,以便进一步开展残膜回收,减轻或消灭残膜污染提供理论依据。 二、调查方法 选取连作两年和麦棉轮作的覆膜棉田各一块,每块地随机取样3个点,每样点测定面积为1个平方米,分表土层和0—30厘米耕层测定。棉秆上所带残膜量同样在这两种不同覆膜次数的地块中测定,方法是在抱出田外的棉秆中随机取出一定数量的棉秆,然后将棉秆。 展开更多
关键词 棉田 残膜留量 跟踪测定
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影响奶牛血清甲状腺素(T_4)水平的研究 被引量:1
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作者 徐魁梧 戴杏庭 +3 位作者 徐芬义 蔡虎生 陈宝明 吴迪 《中国奶牛》 1993年第3期43-45,51,共4页
奶牛血液中的一些生理指标一般是相对恒定的,但常因外界及机体状况的改变致使某些指标发生变化。甲状腺素(T<sub>4</sub>)参与机体代谢的调节,影响免疫性状,对奶牛的生产和生殖机能有重要的作用。国内外学者如Hemken(197... 奶牛血液中的一些生理指标一般是相对恒定的,但常因外界及机体状况的改变致使某些指标发生变化。甲状腺素(T<sub>4</sub>)参与机体代谢的调节,影响免疫性状,对奶牛的生产和生殖机能有重要的作用。国内外学者如Hemken(1976),Miller(1981),向(土寿)(1981)对奶牛T<sub>4</sub>进行了测定,结论不尽一致。为进一步摸清影响甲状腺素含量的原因,1989年我们在南京农业大学实验牧场对20头奶牛进行了一年的跟踪测定。 展开更多
关键词 T4 奶牛饲养 生殖机能 血清甲状腺素 泌乳牛 奶牛血清 生理指标 牛群 跟踪测定 黑白花
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光电经纬仪的通用传感器接口
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作者 徐抒岩 《光学精密工程》 EI CAS CSCD 1994年第3期70-73,共4页
论述了现代光电经纬仪采用多传感器的必要性。提出了多传感器的通用数据接口并进行了详细描述。
关键词 光电经纬仪 传感器 接口 导弹 跟踪测定
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胡椒油微胶囊的试验研究
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作者 林草 《世界热带农业信息》 2005年第7期23-23,共1页
关键词 胡椒油 微胶囊 试验研究 改性淀粉 总碱含量 壁材 非挥发性 跟踪测定 保存效果 保存技术
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Passive target tracking with intermittent measurement based on random finite set 被引量:4
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作者 罗小波 范红旗 +1 位作者 宋志勇 付强 《Journal of Central South University》 SCIE EI CAS 2014年第6期2282-2291,共10页
In the tracking problem for the maritime radiation source by a passive sensor,there are three main difficulties,i.e.,the poor observability of the radiation source,the detection uncertainty(false and missed detections... In the tracking problem for the maritime radiation source by a passive sensor,there are three main difficulties,i.e.,the poor observability of the radiation source,the detection uncertainty(false and missed detections)and the uncertainty of the target appearing/disappearing in the field of view.These difficulties can make the establishment or maintenance of the radiation source target track invalid.By incorporating the elevation information of the passive sensor into the automatic bearings-only tracking(BOT)and consolidating these uncertainties under the framework of random finite set(RFS),a novel approach for tracking maritime radiation source target with intermittent measurement was proposed.Under the RFS framework,the target state was represented as a set that can take on either an empty set or a singleton; meanwhile,the measurement uncertainty was modeled as a Bernoulli random finite set.Moreover,the elevation information of the sensor platform was introduced to ensure observability of passive measurements and obtain the unique target localization.Simulation experiments verify the validity of the proposed approach for tracking maritime radiation source and demonstrate the superiority of the proposed approach in comparison with the traditional integrated probabilistic data association(IPDA)method.The tracking performance under different conditions,particularly involving different existence probabilities and different appearance durations of the target,indicates that the method to solve our problem is robust and effective. 展开更多
关键词 passive target tracking maritime target joint detection and tracking intermittent measurement random finite set poor observability
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Sliding-mode control of path following for underactuated ships based on high gain observer 被引量:1
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作者 秦梓荷 林壮 +1 位作者 孙寒冰 杨东梅 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第12期3356-3364,共9页
A nonlinear robust control strategy is proposed to force an underactuated surface ship to follow a predefined path with uncertain environmental disturbance and parameters.In the controller design,a high-gain observer ... A nonlinear robust control strategy is proposed to force an underactuated surface ship to follow a predefined path with uncertain environmental disturbance and parameters.In the controller design,a high-gain observer is used to estimate velocities,thus only position and yaw angle measurements are required.The control problem of underactuated system is transformed into a control of fully actuated system through adopting an improved line-of-sight(LOS) guidance law.A sliding-mode controller is designed to eliminate the yaw angle error,and provide the control system robustness.The control law is proved semi-globally exponentially stable(SGES) by applying Lyapunov stability theory,and numerical simulation using real data of a monohull ship illustrates the effectiveness and robustness of the proposed methodology. 展开更多
关键词 underactuated ship path following sliding-mode control line-of-sight guidance high gain observer
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