襄阳夏枯草(Prunella vulgaris)群落基本特征

报道了湖北省襄阳市一野生夏枯草种群。种群面积为8～10 m2,植株数为30～40株,为小种群。频度为100%,盖度为10%,密度约4株/m2。果穗平均数为5.6个/株。过度耕作和采摘是导致夏枯草中药材资源减少的重要原因。     

企业货运铁路取送车作业智能优化方法

针对综合布局(同时具有放射状和树枝状)的企业货运铁路专用线的特点,提出了一种智能优化方法.该方法在建立取送作业模型的基础上,对问题进行分解,提出了两级优化策略,即先并行求解各车间内树枝状取送作业的子优化问题、再综合求解车间之间放射状取送作业优化问题.依据该优化策略,设计了一种融合遗传算法和蚁群算法的遗传精英蚁群优化算法(GAASelite)求解取送车作业优化问题.实验仿真结果证明,该方法能有效地优化铁路取送车作业问题.     

On-line trajectory generation of midcourse cooperative guidance for multiple interceptors

The cooperative interception trajectories generation of multiple interceptors to hypersonic targets is studied.First,to solve the problem of on-line trajectory generation of the single interceptor,a generation method based on neighborhood optimal control is adopted.Then,when intercepting the strong maneuvering targets,the single interceptor is insufficient in maneuverability,therefore,an on-line multiple trajectories generation algorithm is proposed,which uses the multiple interceptors intercept area(IIA)to cover the target's predicted intercept area(PIA)cooperatively.Through optimizing the interceptors'zero control terminal location,the trajectories are generated on-line by using the neighborhood optimal control method,these trajectories could make the IIA maximally cover the PIA.The simulation results show that the proposed method can greatly improve the interception probability,which provides a reference for the collaborative interception of multiple interceptors.     

建瓯市土地利用程度变化及其驱动力分析

利用“土地利用程度变化模型”、GIS软件等来研究建瓯市土地利用的动态变化．并将分析结果用图表形式表示，直观显示了建瓯市从1998—2000年的土地利用变化情况，用相关分析方法探讨建瓯市土地利用程度变化差异的驱动力，并对其今后的发展提出适当的建议．     

漆酚树酯的热氧化分析

用差热分析的方法探讨了漆酚树酯的热氧化情况，测定了反应活化能，讨论了影响漆酚树酯热稳定性的因素     

以科学发展观促进固原经济快速发展

阐述了科学发展观的重大指导意义,探讨了如何以科学发展观指导固原经济又好又快地发展。     

青银高速济南黄河大桥46m现浇箱梁支架施工

以青银高速公路济南黄河大桥为例,详细介绍了46m连续箱梁如何采用自制门式钢支架施工,并阐述了支架的性能和工作原理。     

Synthesis of high molecular weight polylactic acid from aqueous lactic acid co-catalyzed by tin(II)chloride dihydrate and succinic anhydride

Poly(lactic acid) (PLA) is widely used as biodegradable plastic and biomedical materials due to its excellent me- chanical properties and biodegradable characterization. The price of poly(lactic acid) has gradually become com- petitive to the average alkene polymers since the method for the preparation of lactic acid from starch fermentation has been developed. With the decline of petroleum re- serves, much attention is devoted to polylactic acid due to its environmentally benignancy and its …     

浅述钢筋混凝土结构施工期可靠性分析与控制

结构在施工期可靠度的分析对于保证结构施工安全具有重要的意义,本文结合钢筋混凝土结构在施工期的特点,对结构在施工期内的荷载及抗力的特点进行了分析,并对施工期的可靠性分析方法及施工期结构的可靠性控制进行了阐述.     

汽车轮胎温度智能监测与控制系统的研究

汽车在行驶的过程中由于行驶时间过长、天气温度过高、与地面的摩擦等一系列原因,经常会使汽车的轮胎温度过高,轻则会对车辆行驶造成影响,重则造成交通事故.本文介绍一种基于89C2051单片机的轮胎温度监测系统,分析该系统的原理及其软、硬件设计.系统通过温度传感器对轮胎温度实时监测,并通过数码管进行显示与处理,能大大提高汽车行驶的安全性.