一种传感器网络移动栅栏部署算法

栅栏覆盖是传感器网络研究中的热点问题,现有有关栅栏覆盖研究大多针对静态兴趣区域的栅栏覆盖,而对于实际应用中如海洋污染、森林火灾、部队行军等的栅栏覆盖应用不适用;该文主要针对动态对象研究移动传感器网络的有效栅栏覆盖;抽象了问题模型并提出了栅栏覆盖评价指标,然后结合凸优化理论提出了一种分布式的移动栅栏覆盖算法;通过3个不同场景分别测试了算法在400*600 m的区域中随机部署有50个移动传感器节点对于不同动态对象构建一条封闭栅栏带所花费的时间以及栅栏带动态形成时的移动距离;测试结果算法能够快速有效实现动态区域的栅栏覆盖。     

Influence of scanning velocity on bovine shank bone ablation with pulsed CO2 laser

The influence of scanning speed on hard bone tissue ablation is studied with a 10.6-μm laser. The groove morphology and the thermal damage created in bovine shank bone by pulsed CO2 laser are examined as a function of incident fluence by optical microscope following standard histological processing. The results show that ablation groove width, depth and ablation volume, as well as the zone of thermal injury, increase gradually with incident fluence. As compared to the result for high scanning speed, the lower scanning speed always produces larger ablation volume but thicker zone of thermal injury. It is evident that scanning speed plays an important role in the ablation process. In clinical applications, it is important to select appropriate scanning speed to obtain both high ablation rates and minimal thermal injury.     

基于主模型的协同设计软件架构技术研究

基于统一数据源的协同设计理念,结合运载火箭总体设计与数据模型特点,通过定义基础信息模型、概念模型、参数模型、外部定义模型四种数据模型,提出了针对运载火箭产品的通用主模型构建方法,并搭建了基于主模型的协同设计软件系统整体架构,此架构包含主模型管理系统、主模型建模工具及应用客户端三部分,能实现多专业协同设计过程中数据与版本的统一管理、技术状态一致性分析、谱系追踪、数据展示与应用等功能,为运载火箭的总体协同设计提供工具支撑。     

CuCl与SiO_2-TiO_2载体相互作用的密度泛函理论研究

以SiO2簇模型为基体,通过Ti原子取代建立Ti中心原子上连接0个或1个OH基团的典型SiO2-TiO2复合氧化物模型来模拟处于体相中和表面上的四配位Ti(IV)中心.采用广义梯度近似的密度泛函理论(DFT-GGA)研究了CuCl与SiO2-TiO2载体的相互作用.计算结果表明,在SiO2基体中嵌入Ti(IV)离子可以大大加强CuCl与氧化物载体之间的相互作用,使CuCl/SiO2-TiO2催化剂的结构更稳定.分子前线轨道表明Cu(I)作为催化剂的活性中心贡献了HOMO轨道,容易失去电子;Ti(IV)中心原子贡献LUMO轨道,容易得到电子,计算结果与实验事实相一致.     

Solutions with interior bubble and boundary layer for an elliptic Neumann problem with critical nonlinearity

We study positive solutions of the equation ${\mathrm{?}}^2\mathrm{\Delta }u?u+u^{\frac{n+2}{n?2}}=0$, where $n=3,4,5$ and $\mathrm{?}>0$ is small, with Neumann boundary condition in a unit ball B. We prove the existence of solutions with an interior bubble at the center and a boundary layer at the boundary ?B. To cite this article: J. Wei, S. Yan, C. R. Acad. Sci. Paris, Ser. I 343 (2006).     

正常和嵌合肿瘤乳腺温度分布特征的有限元分析

基于乳腺解剖学结构和生理学特征,建立了适合应用于正常和嵌合肿瘤乳腺三维热传递的分析模型.该模型综合考虑了乳腺代谢产热、血液灌注和动静脉血管与乳腺组织之间的热交换等因素对温度场的影响.数值研究了正常和嵌合肿瘤乳腺的温度分布特征,着重分析代谢产热、血液灌注率、乳腺肿瘤的大小、位置与数目以及空气对流系数、环境温度等因素对乳腺温度分布的影响.结果表明:血液灌注率、代谢产热、乳腺肿瘤的大小、位置与数目对乳腺温度分布特征的影响明显;环境条件对嵌含肿瘤乳腺的体表温度分布影响较大.研究结果将有助于指导乳腺红外热图像的实验并为其定性分析提供重要的参考.     

Two-weight Caccioppoli inequalities for solutions of nonhomogeneous -harmonic equations on Riemannian manifolds

In this paper, we first prove the local two-weight Caccioppoli inequalities for solutions to the nonhomogeneous -harmonic equation of the form . Then, as applications of the local results, we prove the global two-weight Caccioppoli-type inequalities for these solutions on Riemannian manifolds.

     

Measurement of crater geometries after laser ablation of bone tissue with optical coherence tomography

The feasibility of measuring crater geometries by use of optical coherence tomography (OCT) is examined. Bovine shank bone on a motorized translation stage with a motion velocity of 3 mm/s is ablated with a pulsed CO2 laser in vitro. The laser pulse repetition rate is 60 Hz and the spot size on the tissue surface is 0.5 mm. Crater geometries are evaluated immediately by both OCT and histology methods after laser irradiation. The results reveal that OCT is capable of measuring crater geometries rapidly and noninvasively as compared to histology. There are good correlation and agreement between crater depth estimates obtained by two techniques, whereas there exists distinct difference between crater width estimates when the carbonization at the sides of craters is not removed.     

Optically noninvasive measurement of the light transport properties of human meridians

To confirm the existence and properties of human meridians, the optical transport properties along the pericardium meridian and tissues around the pericardium meridian are studied noninvasively on twenty healthy volunteers in vivo and then compared with each other. Our study shows that the light propagating along the meridian and non-meridian directions both conform to the Beer's exponential attenuation law. However, statistical analysis of the results suggests that the optical transport properties of human meridian differ from those of the surrounding tissues over a low modulated frequency range (P < 0.01), and light attenuation along the pericardium meridian is significantly less than that along the non-meridian direction. These findings not only indicate the existence of acupuncture meridian from the point of view of biomedical optics, but also shed new light on an approach to investigation of human meridians.     

Theoretical analysis of backscattered polarization patterns of turbid media containing glucose

Single scattering model and Stokes-Mueller formalism are introduced to investigate the influence of glucose on backscattered polarization patterns in turbid media. Glucose molecules rotate the polarization plane and induce changes in backscattered Mueller matrix patterns. Some Mueller matrix elements present higher optical rotation as the concentration of glucose augments. Using image subtraction and integration,linear relationship between low glucose concentration in the physiological range and optical rotation degree can be derived.