Intermediate targets and segmental pathfinding

Neurons must often extend axons over fairly long distances, making multiple changes in their trajectory of growth before arriving at their final target. It has become clear that as growth cones navigate these complex projections, they typically extend toward a number of intermediate targets before they contact their final target. Recent work from a variety of systems has identified intermediate targets that seem to play similar roles in vertebrate and invertebrate nervous system development. From these examples it appears that a general model of axon guidance can be proposed whereby neurons are guided to their targets segmentally. Within each segment, an intermediate target appears to be the primary target for growth cone recognition and thus the completion of the journey to the final target is determined by a series of successful segmental pathfinding decisions.     

多传感器阵列信号的分布式恒虚警检测

对于均匀Gauss背景中的Swerlling II型起伏目标的多传感器分布式恒虚警检测,为了充分利用阵列雷达接收信号间的相位关系,采用了相干检波信号处理方式.针对局部检测统计量信息量大,通信带宽小的特点,结合实际检测中信号强度未知等困难,提出了广义似然比恒虚警(GLR-CFAR)局部处理算法.仿真结果表明,该检测方式性能接近最优性能,传感器积累对信噪比改善明显,达到3～7 dB, 提高小信号目标的检测概率,且具有实现简单的优点.因此,此方法适合用于多雷达检测场合.     

FDTD modeling of transient scattering by subsurface targets

In this paper, a two-dimensional (2-D) finitedifference time-domain method (FDTD) scheme is used to simulate the transient scattering characteristics of buried objects, which are modeled by columns of arbitrary permittivities, conductivities, and sizes. The FDTD soil is modeled by isotropic, homogeneous and lossy media. The standing-traveling wave boundary condition (STWBC) that can simplify calculation and save CPU storage is used for modeling physical absorbers inside the FDTD computational dornairL Reflection of electromagnetic pulses incident on a layered medium and transient scattering by the ground and an underground airsqu are cylinder are computed. These results verify the validity of the FDTD scheme by comparisons with those shown in some references. Numerical results presented in the final part of this paper are desirable and meaningful, explicitly distinguishing echo waves stemming from the ground and the buried ohjects.     

党建“新的伟大工程”浅释——为党的80周年诞辰而作

本文依据党的十五大精神和江泽民关于党的建设的一系列重要指示,对党的建设“新的伟大工程”的战略目标、主要任务、根本问题等的内涵作了初步的阐释。     

怎样说化学课

说课,是近年来教育界在强化教师基本功训练活动中形成的一种新型的教学研究模式.会说课,已成为现代教师必须具备的教学基本功之一.文章阐述了说课是什么和说课应注意什么等问题,并从教学目标、教学对象、教材、教学策略、教学媒体和教学评价等方面论述了应怎样说化学课.     

多被动探测器对多目标定位模型及仿真

对于探测目标间距较小的目标群,提出使用3个被动探测器的探测模型。首先,重点研究了多被动探测器对多目标进行定位的目标关联问题;然后,建立了3个被动探测器的机动模型,提出了3个被动探测器多目标定位的目标关联算法。最后,通过仿真分析了各种因素对目标关联的影响。仿真结果表明提出的3个被动探测器机动模型和目标关联算法是有效的。     

失实报道产生根源论析

失实报道严重损害了媒体的公信力,在社会上造成了恶劣影响,对舆论的导向起了负面作用。本文针对失实报道,从理论上分析其产生的根源,倡导新闻打假,并进一步阐述新闻真实性与建设和谐的舆论氛围的关系。     

广告代言人相关法律问题探究

阐述广告市场的发展蒸蒸日上,近年来,由于明星代言广告所引发的相关问题受到了媒介和学界的广泛关注。指出关于广告代言人的法律责任等相关问题的研究还没有定论。从分析问题及原因出发,提出一些对策,以利保护消费者的权利,并对我国关于广告代言人的法律完善有所裨益。     

论防止会计信息的失真

文章对当前会计信息失真的现状及产生原因进行了系统分析，并提出了防止信息失真的对策。