Shallow gas in the muddy sediments of Eckernförde Bay, Germany

The seafloor of central Eckernförde Bay is characterised by soft muddy sediments that contain free methane gas. Bubbles of free gas cause acoustic turbidity which is observed with acoustic remote sensing systems. Repeated surveys with subbottom profiler and side scan sonar revealed an annual period both of depth of the acoustic turbidity and backscatter strength. The effects are delayed by 3–4 months relative to the atmospheric temperature cycle. In addition, prominent pockmarks, partly related to gas seepage, were detected with the acoustic systems. In a direct approach gas concentrations were measured from cores using the gas chromatography technique. From different tests it is concluded that subsampling of a core should start at its base and should be completed as soon as possible, at least within 35 min after core recovery. Comparison of methane concentrations of summer and winter cores revealed no significant seasonal variation. Thus, it is concluded that the temperature and pressure influences upon solubility control the depth variability of acoustic turbidity which is observed with acoustic remote sensing systems. The delay relative to the atmospheric temperature cycle is caused by slow heat transfer through the water column. The atmospheric temperature cycle as ‘exiting function’ for variable gas solubility offers an opportunity for modelling and predicting the depth of the acoustic turbidity. In practice, however, small-scale variations of, e.g., salinity, or gas concentration profile in the sediment impose limits to predictions. In addition, oceanographic influences as mixing in the water column, variable water inflow, etc. are further complications that reduce the reliability of predictions.

Glutathione-capped CdTe quantum dots for the sensitive detection of glucose

A simple and sensitive assay system for glucose based on the glutathione (GSH)-capped CdTe quantum dots (QDs) was developed. GSH-capped CdTe QDs exhibit higher sensitivity to H2O2 produced from the glucose oxidase catalyzed oxidation Of glucose, and are also more biocompatible than other thiols-capped QDs. Based on the quenching of H2O2 on GSH-capped QDs, glucose can be detected. The detection conditions containing reaction time, the concentration of glucose oxidase and the sizes of QDs were optimized and the detection limits for glucose was determined to be 0.1 mu M; two detection ranges of glucose from 1.0 mu M to 0.5 mM and from 1.0 mM to 20 mM, respectively Were obtained. The detection limit was almost a 1000 times lower than other QDs-based optical glucose sensing systems. The developed glucose detection system was simple and facile with no need of complicated enzyme immobilization and modification of QDs.

Regulation of the Edwardsiella tarda Hemolysin Gene and luxS by EthR

Edwardsiella tarda is a pathogen with a broad host range that includes human and animals. The E. tarda hemolysin (Eth) system, which comprises EthA and EthB, is a noted virulence element that is widely distributed in pathogenic isolates of E. tarda. Previous study has shown that the expression of ethB is regulated by iron, which suggests the possibility that the ferric uptake regulator (Fur) is involved in the regulation of ethB. The work presented in this report supports the previous findings and demonstrates that ethB expression was decreased under conditions when the E. tarda Fur (Fur(Et)) was overproduced, and enhanced when Fur(Et) was inactivated. We also identified a second ethB regulator, EthR, which is a transcription regulator of the GntR family. EthR represses ethB expression by direct interaction with the ethB promoter region. In addition to ethB, EthR also modulates, but positively, luxS expression and AI-2 production by binding to the luxS promoter region. The expression of ethR itself is subject to negative autoregulation; interference with this regulation by overexpressing ethR during the process of infection caused (i) drastic changes in ethB and luxS expressions, (ii) vitiation in the tissue dissemination and survival ability of the bacterium, and (iii) significant attenuation of the overall bacterial virulence. These results not only provide new insights into the regulation mechanisms of the Eth hemolysin and LuxS/AI-2 quorum sensing systems but also highlight the importance of these systems in bacterial virulence.

基于现场总线的工业机器人联网

本文根据国内工业机器人技术开发和应用现状及其技术发展趋势 ,进行了基于现场总线的工业机器人联网技术的研究和开发 ,并将机器人作为生产线底层设备 ,实现了工业机器人网络的互联 .本文介绍了这个系统的硬件结构、上位监控机软件实现、控制器软件实现以及系统完成的功能 .

基于QNX实时系统的行为辅助机器人控制系统

论文设计研制了行为辅助机器人验证平台,以此平台为基础可以针对行为辅助机器人进行力控制研究。针对机器人力控制的实际要求,设计了行为辅助机器人柔性关节结构,辨识了系统参数。基于QNX实时操作系统设计了控制系统软件。机器人控制系统软件主要包括传感器数据采集和控制算法两部分,可以满足柔性关节控制需求。

网络遥操作机器人采样系统模型与控制研究

网络遥操作机器人系统是网络技术与机器人技术相结合的产物。它延伸了操作者的感知和操作能力，使操作者可以置身于安全的环境中而完成危险环境中的作业任务；提高了机器人对工作环境的适应能力，辅之以操作者的决策，机器人可以工作于非结构化的工作环境中。网络遥操作机器人技术作为机器人学的一个重要分支，近十几年来受到许多研究机构和研究人员的关注和重视。 本文针对网络遥操作机器人采样控制结构，通过控制策略解决非结构环境下网络遥操作机器人的实时控制问题。为此，首先研究了网络遥操作机器人采样系统建模问题。目前，关于网络遥操作机器人采样系统模型大多是针对单采样周期的，主从端不同采样周期的统一模型目前还没有相关报道。由于操作者是网络遥操作机器人采样系统的组成部分，因此若建立网络遥操作机器人采样系统模型首先要建立操作者模型。然而由于操作者建模问题比较复杂，目前在遥操作系统建模时，一般都避开了操作者建模问题。本文在分析了现有的遥操作控制方式和遥操作系统模型的基础上，主要针对网络遥操作机器人采样系统模型和控制问题进行研究。 操作者模型研究方面，主要以操作者用小臂操作具有力反馈功能的操纵杆为例，研究操作者操作操纵杆过程的动态模型建模方法。首先对人体骨骼肌肌肉力学模型中不可测量，即肌肉激活度，通过实验进行研究，得出在操作者保持紧张程度不变情况下“肌肉激活度”与肌肉收缩长度的关系。在此基础上，考虑手臂的动力学特性、操纵杆的动力学特性，建立了肌肉力驱动的手臂—操纵杆系统动力学模型。在操作者模型的基础上，设计动态补偿器，补偿操作者操作操纵杆的动态过程，解决由于肌肉动态特性被污染所造成的操作者所想与所做不一致的问题，克服操作者操作时延，提高网络遥操作机器人系统的性能。 遥操作机器人采样系统模型研究方面，首先针对主从端不同采样周期的网络遥操作机器人采样控制结构，通过引入双端口RAM的方法，实现网络遥操作机器人系统主从端的采样同步；在网络遥操作机器人采样同步控制结构模型的基础上，建立从端离散状态空间表达式，利用提升技术对从端离散状态空间表达式按遥操作周期提升，利用采样系统理论得到主从端统一的网络遥操作机器人采样系统模型；最后对从端系统提升前后的稳定性、可控性、可观测性进行分析，得出从端系统提升前后稳定性、可控性、可观测性不变的结论。 遥操作控制策略研究方面，提出基于时延预测的采样切换控制方法。首先对互联网节点间的网络时延进行测试分析，得出任意两个网络节点间时延分布规律，即任意时间段内网络时延的概率密度都可以用平移Gamma分布曲线描述。采用拟合样本概率密度曲线的方法，对平移Gamma参数进行预估，得出平移Gamma分布的种类，进而根据平移Gamma分布的种类，确定出网络时延的均值，最后确定出期望的采样周期；为了实现任意采样周期下切换系统的稳定控制，对采样切换系统的稳定性进行了研究，得到如下结论，即如果从端系统一致渐进稳定，则对从端实行任意采样切换控制时网络遥操作机器人采样系统是稳定的。 为了对所研究内容进行实验验证，以移动机器人为被控对象，搭建了一个具有力反馈控制和局部自主功能的网络遥操作机器人采样系统实验平台。用人工势场法建立了虚拟力模型并给出了虚拟力在力反馈操纵杆上的实现方法；以移动机器人自主避障为例，给出了从端自主的模糊控制设计方法和实验系统遥操作软件设计方法。 实验结果证明了所提出的模型和控制方法是有效的、可行的，对于建立性能良好的网络遥操作机器人系统具有现实意义。本文所研究的许多结论，对于一般网络遥操作机器人系统的理论研究和实际应用也具有一定的参考价值。

Micro-systems for Optical Protein-Chip

Protein-Chip as micro-assays for the determination of protein interaction, the analysis, the identification and the purification of proteins has large potential applications. The Optical Protein-Chip is able to detect the multi-interaction of proteins and multi-bio-activities of molecules directly and simultaneously with no labeling. The chip is a small matrix on solid substrate containing multi-micro-area prepared by microfabrication with photolithography or soft lithography for surface patterning, and processed with surface modification which includes the physical, chemical, and bio-chemical modifications, etc. The ligand immobilization, such as protein immobilization, especially the oriented immobilization with low steric hindrance and high bio-specific binding activity between ligand and receptor is used to form a sensing surface. Each area of the pattern is corresponding to only one bioactivity. The interval between the areas is non-bioactive and optically extinctive. The affinity between proteins is used to realize non-labeling microassays for the determination of protein identification and protein interaction. The sampling of the chip is non-disturbing, performed with imaging ellipsometry and image processing on a database of proteins.

Small scale, grain size and substrate effects in nano-indentation experiment of film-substrate systems

The mechanical properties of film-substrate systems have been investigated through nano-indentation experiments in our former paper (Chen, S.H., Liu, L., Wang, T.C., 2005. Investigation of the mechanical properties of thin films by nano-indentation, considering the effects of thickness and different coating-substrate combinations. Surf. Coat. Technol., 191, 25-32), in which Al-Glass with three different film thicknesses are adopted and it is found that the relation between the hardness H and normalized indentation depth h/t, where t denotes the film thickness, exhibits three different regimes: (i) the hardness decreases obviously with increasing indentation depth; (ii) then, the hardness keeps an almost constant value in the range of 0.1-0.7 of the normalized indentation depth h/t; (iii) after that, the hardness increases with increasing indentation depth. In this paper, the indentation image is further investigated and finite element method is used to analyze the nano-indentation phenomena with both classical plasticity and strain gradient plasticity theories. Not only the case with an ideal sharp indenter tip but also that with a round one is considered in both theories. Finally, we find that the classical plasticity theory can not predict the experimental results, even considering the indenter tip curvature. However, the strain gradient plasticity theory can describe the experimental data very well not only at a shallow indentation depth but also at a deep depth. Strain gradient and substrate effects are proved to coexist in film-substrate nano-indentation experiments. (c) 2006 Elsevier Ltd. All rights reserved.

The characterization of plastic flow in three different bulk metallic glass systems

Plastic deformation behaviors of Zr52.5Al10Ni10Cu15Be12.5, Mg65Cu25Gd10 and Pd43Ni10Cu27P20 bulk metallic glasses (BMGs) are studied by using the depth-sensing nanoindentation, macroindentation and uniaxial compression. The significant difference in plastic deformation behavior cannot be correlated to the Poisson's ratio or the ratio of shear modulus to bulk modulus of the three BMGs, but can be explained by the free volume model. It is shown that the nucleation of local shear band is easy and multiple shear bands can be activated in the Zr52.5Al10Ni10Cu15Be12.5 alloy, which exhibits a distinct plastic strain during uniaxial compression and less serrated flow during nanoindentation. (c) 2006 Elsevier B.V. All rights reserved.

Design and path planning for a remote-brained service robot

This paper presents a novel robot named "TUT03-A" with expert systems, speech interaction, vision systems etc. based on remote-brained approach. The robot is designed to have the brain and body separated. There is a cerebellum in the body. The brain with the expert systems is in charge of decision and the cerebellum control motion of the body. The brain-body. interface has many kinds of structure. It enables a brain to control one or more cerebellums. The brain controls all modules in the system and coordinates their work. The framework of the robot allows us to carry out different kinds of robotics research in an environment that can be shared and inherited over generations. Then we discuss the path planning method for the robot based on ant colony algorithm. The mathematical model is established and the algorithm is achieved with the Starlogo simulating environment. The simulation result shows that it has strong robustness and eligible pathfinding efficiency.

Design and path planning for a remote-brained service robot

This article introduced an effective design method of robot called remote-brain, which is made the brain and body separated. It leaves the brain in the mother environment, by which we mean the environment in which the brain's software is developed, and talks with its body by wireless links. It also presents a real robot TUT06-B based on this method which has human-machine interaction, vision systems, manipulator etc. Then it discussed the path planning method for the robot based on ant colony algorithm in details, especially the Ant-cycle model. And it also analyzed the parameter of the algorithm which can affect the convergence. Finally, it gives the program flow chat of this algorithm.

Spatial-temporal characteristics of siping urban expansion based on remote sensing and GIS

Based on the RS and GIS methods, Siping city is selected as a study case with four remote sensing images in 25 years. Indices of urban morphology such as fractal dimension and compactness are employed to research the characteristics of urban expansion. Through digital processing and interpreting of the images, the process and characteristics of urban expansion are analysed using urban area change, fractal dimension and compactness. The results showed that there are three terms in this period. It expended fastest in the period of 1979~1991, and in the period of 1992~2001, the emphases on urban redevelopment made it expended slower. And this is in agreement with the Siping Statistical Yearbook. This indicates that the united of metrics of urban morphology and statistical data can be used to satisfactorily describe the process and characteristics of urban expansion. © 2008 IEEE.

Stabilization of Dynamic Systems for Multiple Omni-Directional Mobile Robots

本文考虑了由2个全方位移动机器人组成的混合动力学系统的协调拟镇定问题.利用机器人位置之间的向量与机器人目标之间向量的内积,设计了多步拟镇定律,该控制律能够在避碰后按指数速率运动到目标点,且在整个过程中两机器人之间的距离不小于避碰的安全距离.最后对2个全方位移动机器人进行了仿真,验证了所给方法的有效性。