试论滑坡基本地质模型

滑坡基本地质模型是工程地质学研究的一个基础理论问题。本文在综合滑坡分类体系基础上 ,从滑坡活动各要素的地位与作用出发 ,遴选最能表征其活动特点的主要因素 ,作为建模的基本要素 ,形成滑坡基本地质模型体系。随着勘探阶段的不同 ,针对不同的应用目的 ,可以建立滑坡具体地质模型体系。     

Laws of nature that define biological action and perception

We describe a physical approach to biological functions, with the emphasis on the motor and sensory functions. The approach assumes the existence of biology-specific laws of nature uniting salient physical variables and parameters. In contrast to movements in inanimate nature, actions are produced by changes in parameters of the corresponding laws of nature. For movements, parameters are associated with spatial referent coordinates (RCs) for the effectors. Stability of motor actions is ensured by the abundant mapping of RCs across hierarchical control levels. The sensory function is viewed as based on an interaction of efferent and afferent signals leading to an iso-perceptual manifold where percepts of salient sensory variables are stable. This approach offers novel interpretations for a variety of known neurophysiological and behavioral phenomena and makes a number of novel testable predictions. In particular, we discuss novel interpretations for the well-known phenomena of agonist-antagonist co-activation and vibration-induced illusions of both position and force. We also interpret results of several new experiments with unintentional force changes and with analysis of accuracy of perception of variables produced by elements of multi-element systems. Recently, this approach has been expanded to interpret motor disorders including spasticity and consequences of subcortical disorders (such as Parkinson's disease). We suggest that the approach can be developed for cognitive functions.     

中国现当代文学学科研究的一个新视域—五四时期至1950年代初期中国籍作者的域外华文书写

五四时期至1950年代初期,中国籍作者在海外创作了大量的华文书写,这些作品已然成为中国现当代文学的域外延伸部分。然而长期以来,中国大陆学术界并未将其整体性地纳入中国现当代文学学科研究领域,而是笼统地将其归类于海外华文文学学科,由此局囿了中国现当代文学学科研究的广度和深度。从历史角度和客观史实来看,本时段的域外华文书写具有无可争辩的中国文学属性,并且是中国现当代文学“主潮”跨越国家疆域后所开拓的“海外支流”。同时由于特殊的历史原因,本时段的域外华文书写具有“双重归属”的特性,即其一方面属于中国现当代文学学科的“华侨文学”,另一方面又属于海外华文文学领域的“华人文学”。在跨越国家疆域和学科分类的视角下,将其整体性地纳入中国现当代文学学科的研究领域,可以为中国现当代文学学科提供新的研究视域并开拓新的研究空间。     

用核磁共振方法研究弱交联高分子体系的微观运动状态及微观结构特征

用核磁共振１３Ｃ自旋－自旋弛豫时间Ｔ２表征了以离子微区为表观交联点的以甲基丙烯酸丁酯－丙烯酸共聚物为基础的弱交联高分子体系的微观链运动特征，及体系中溶剂分子的运动特征，结果表明：聚合物主链表现为快、慢两种运动状态，聚合物体系存在多相结构；溶剂分子也表现出两种不同的运动状态，从而间接反应了聚合物体系的微观结构。     

Nematic liquid crystals formed by living amoeboid cells

Interacting cells have the ability to form liquid crystal phases: (i) A cluster of a polar nematic liquid crystal is formed by cells which emit molecules for attracting other cells and (ii) an apolar nematic liquid crystal is formed by elongated cells which have an anisotropic steric repulsion. The angle distribution function is predicted by using the characteristics of an automatic controller where the extracellular guiding field is approximated by two-dimensional mean-field. The nematic liquid crystal state is quite well described by the model. Received 7 September 1998 and Received in final form 4 March 1999     

Synchronization of rotating helices by hydrodynamic interactions

Some types of bacteria use rotating helical flagella to swim. The motion of such organisms takes place in the regime of low Reynolds numbers where viscous effects dominate and where the dynamics is governed by hydrodynamic interactions. Typically, rotating flagella form bundles, which means that their rotation is synchronized. The aim of this study is to investigate whether hydrodynamic interactions can be at the origin of such a bundling and synchronization. We consider two stiff helices that are modelled by rigidly connected beads, neglecting any elastic deformations. They are driven by constant and equal torques, and they are fixed in space by anchoring their terminal beads in harmonic traps. We observe that, for finite trap strength, hydrodynamic interactions do indeed synchronize the helix rotations. The speed of phase synchronization decreases with increasing trap stiffness. In the limit of infinite trap stiffness, the speed is zero and the helices do not synchronize.Electronic supplementary material Two movies, comparing the dynamics for strong and weak anchoring, are only available in electronic form at and are accessible for authorised users.     

浅水海豚三维空间定位与发声源级测量

详细阐述了单水听器和水听器阵列进行海豚定距定位的几何模型,以及利用不同接收通道间的时延差计算空间坐标的方法,结合实验数据计算了海豚在水中的三维空间坐标和回声定位信号的声源级,并开展了海豚运动轨迹追踪分析。结果表明,相对于单水听器,水听器阵列对测量环境和海豚行为的限制较少,但对采集设备的同步性和硬件连接有较高要求。误差分析表明水听器阵列在大于3 m的距离,定位误差可降低到5%以下。研究结果为精确计算海豚发声源级及海豚的声呐性能及行为研究提供了技术支撑。     

基于运动方向估计的管道滤波算法

管道滤波算法提出了从时域角度解决弱小目标检测问题的思路,对于红外强起伏天空背景中弱点目标的检测问题,管道内强噪音的干扰以及低信噪比的条件会导致检测概率降低的情况出现.本文提出了一种运动方向估计的管道滤波算法,分析了红外弱点目标的运动特性,依据弱点目标在相邻帧间位置具有连贯性的特征,建立了弱点目标的运动方向估计模型.在模型中利用弱点目标逐帧检测的先验位置信息,估计弱点目标的运动方向和轨迹,根据估计结果去除管道内噪音对弱点目标的干扰.仿真结果表明,该方法能够很好地抑制管道内噪音的影响,提高弱点目标的检测概率,增强弱点目标抗管道内噪音干扰的能力.