无线传感器网络中的分布式节点定位方法

提出一种基于流形学习的分布式Hessian局部线性嵌入（DHLLE）定位方法,给出了基于流形学习算法的定位框架.DHLLE方法采用同情最邻近算法来选择节点邻居列表,并应用Hessian局部线性嵌入（HLLE）算法获取传感器网络节点的局部映射,再通过对局部映射合并获得所有节点的全局映射,最后通过对参考节点进行坐标匹配以取得所有节点的全局坐标.仿真结果表明,DHLLE方法能够快速、准确地对节点进行定位,且复杂度低,节点能耗小,其性能超过了分布式加权多维定标等算法.     

最佳视角3-D激光扫描路径的自动确定方法

在3-D激光自动扫描测量中,传感器测量视角的选择直接影响测量数据的完整性和准确性。该文提出了背影轮廓法和凸包法相结合的最佳视角确定方法。利用背光板得到不同角度被测物的背影轮廓图像,根据背影轮廓法得到被测物体的粗略表面数据。以表面数据的凸包多边形作为线结构光传感器的扫描路径,改变传感器的测量视角,完成对被测物的自动扫描。实验结果表明:该方法适用于复杂外形表面的扫描,能够得到完整准确的表面3-D数据。     

领会创新思路激发创新活力

党的十七大高举中国特色社会主义伟大旗帜,充分肯定我国依靠自主创新所取得的重大成绩,同时为科技型企业的发展明确了方向。走中国特色自主创新道路,必须切实领会党中央的创新思路,激发创新活力。企业应积极开展产业集群技术联盟工作,围绕集群企业的共性科技需求,整合科技资源,共建创新平台,降低研发成本,扩大生产规模,提高科技创新效率和自主创新能力。     

电镀Zn-Fe-SiO2复合材料的性能研究

镀锌与Zn-Fe合金广泛用于钢铁零件的防护,但是仍存在钝化液毒性大、环境污染严重、耐蚀性低、氢脆高等不足。本文采用无氰电镀技术制备了Zn-Fe-SiO2复合材料,并测试了Zn-Fe-SiO2复合材料的耐蚀性、孔隙率和氢脆性等综合性能,同时与电镀Zn及Zn-Fe合金进行了对比。实验结果表明:电镀Zn-Fe-SiO2复合材料的耐蚀性及其它综合性能均优于镀锌与Zn-Fe合金,无需钝化处理,环境友好,应用前景广阔。     

微弱光信号检测电路的设计与实现

本文从PIN光伏探测器的特性入手,针对光电检测中放大微弱信号而带来的信噪比和稳定性问题,设计了一种具有电压、电流滤波和相位补偿功能的低噪声光电信号放大电路,并对电路进行了实验分析和实用化处理。     

Right prefrontal laterality of Chinese boys during a Chinese high conflict Stroop task measured by multi-channel near-infrared spectroscopy imaging

Some studies have shown that native Chinese speakers have different laterality in matched Stroop tasks from native English speakers. Recently, many imaging data, which show left laterality of English-matched Stroop interference, have been reported. And a few functional imaging studies have been conducted to investigate the phenomenon of the Chinese version of Stroop task. In this study, functional activity in the lateral prefrontal cortex of a group of normal Chinese boys with functional near-infrared imaging during a Stroop color-word task was measured to show different Stroop interferences in the prefrontal cortex. The results show obvious fluctuation of the cerebral blood volume in the right prefrontal cortex in all boys, which agrees with the finding of previous studies, that is, Chinese native boys have right laterality in their brain when the Chinese version of Stroop color-word task is applied.     

Embryonic development and organogenesis of Chinese giant salamander, Andrias davidianus

The morphology and organogenesis of Chinese giant salamander, Andrias davidianus, in its different developmental periods and stages are described in detail, which provides an intact criterion for distinguishing different stages of its developmental process. Based on the external morphological and internal histological features, six periods including 20 stages of organogenesis of Chinese giant salamander are established, which are cleavage period, blastula period, gastrula period, neurula period, organogenesis stage and hatching stage. Generally, the embryonic development of Chinese giant salamander is consistent with those of Eastern newt, Cynops orientalis, and Black spots frog, R. nigromaculata. However, they have some differences in the early cleavage process and the development of digestive system. The cleavage of Chinese giant salamander, A. davidianus is not a discoidal division type, which is different from other species reported. And the first three cleavages being meridional and a retardant development of its digestive system without halter and sucker existing are the evident features of the embryonic development of Chinese giant salamander.     

Test of magnetic susceptibility and grain-size age models of loess

Ages of the stratigraphic boundary MIS1/2 and MIS3/4 of the Yuanbu loess section in Linxia are used as the basis of the nodal control age. The age of MIS1/2 and MIS3/4 are obtained from the latest international research result—the climatic events recorded in the stalagmite in the Hulu Cave in Nanjing, that MIS1/2 is 11.5 kaB.P. and MIS3/4 is 59.8 kaB.P.. The ages of the two climatic events contain three nodal age control models (Model 1: 0 kaB.P.—59.8 kaB.P.; Model 2: 0 kaB.P.—11.5 kaB.P. and 11.5 kaB.P.—59.8 kaB.P.; Model 3: 11.5 kaB.P.—59.8 kaB.P.), which are used as the nodal control age separately. The deposition times of various stratigraphic horizons are calculated by using the magnetic susceptibility age model and grain-size age model, and then compared with each other. In addition, the AMS14C age, OSL age and the ages of YD and H events are compared with the ages of the corresponding horizons calculated by the three models of nodal control ages. From the analyses of lithologic characters and climatic stages it has been found that both the magnetic susceptibility age model and the grain-size age model have some defects. Because the accurate control ages are selected as the nodal points of the glacial period or interglacial period, the stratigraphic deposition times determined by the high resolution of magnetic susceptibility age model and grain-size age model approximate to the actual ages. As for the relative accuracy of the two age models, the magnetic susceptibility age model is more accurate than the grain-size age model.     

Right prefrontal laterality of Chinese boys during a Chinese high conflict Stroop task measured by multi-channel near-infrared spectroscopy imaging

Some studies have shown that native Chinese speakers have different laterality in matched Stroop tasks from native English speakers.Recently,many imaging data,which show left laterality of English-matched Stroop interference,have been reported.And a few functional imaging studies have been conducted to investigate the phenomenon of the Chinese version of Stroop task.In this study,functional activity in the lateral prefrontal cortex of a group of normal Chinese boys with functional near-infrared imaging during a Stroop color-word task was measured to show different Stroop interferences in the prefrontal cortex.The results show obvious fluctuation of the cerebral blood volume in the right prefrontal cortex in all boys,which agrees with the finding of previous studies,that is,Chinese native boys have right laterality in their brain when the Chinese version of Stroop color-word task is applied.     

Local orthogonal transform for a class of acoustic waveguides

There are some curved interfaces in acoustic waveguides. To compute wave propagation along the waveguides with some marching methods, flattening of the internal interfaces is needed. In this paper, a local orthogonal coordinate transform and an equation transform are constructed to solve the two-dimensional Helmholtz equation for the waveguides bounded by a flat top, a flat bottom and two curved internal interfaces with three layered media. The curved internal interfaces are flattened by the local orthogonal coordinate transform, and the corresponding transformed Helmholtz equation can be solved by some marching methods. This treatment can be extended in multilayered medium waveguides. The one-way reformulation based on the Dirichlet-to-Neumann (DtN) map is then used to reduce the boundary value problem to an initial value problem. Numerical implementation of the resulting operator Riccati equation uses a large range step method to discretize the range variable and a truncated local eigenfunction expansion to approximate the operators. This method is particularly useful for solving long range wave propagation problems in slowly varying waveguides with multilayered medium structure.