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。

Stabilization of Uncertain Nonholonomic Dynamic Systems with Bounded Inputs

The sliding mode approach and the multi-step control strategy are exploited to propose a stabilizing controller for uncertain nonholonomic dynamic systems with bounded inputs. This controller can stabilize the system to an arbitrarily small neighborhood about its equilibrium in a finite time .Its application to a nonholonomic wheeled mobile robot is described. Simulation result shows that the proposed controller is effective

Robust Learning Control for Manipulators with Uncertainty Disturbances Based on Internal Model

In this paper, a disturbance controller is designed for making robotic system behave as a decoupled linear system according to the concept of internal model. Based on the linear system, the paper presents an iterative learning control algorithm to robotic manipulators. A sufficient condition for convergence is provided. The selection of parameter values of the algorithm is simple and easy to meet the convergence condition. The simulation results demonstrate the effectiveness of the algorithm..

内蒙古乌拉特中旗北部宝音图群研究

The Baoyintu Group, lies in Wulate-zhongqi, Inner Mongolia, is a set of medium-grade metamorphic rock series which undergoes complex deformations. It consists of pelite schist, greenschist, plagioclase amphibolite quartzite and marble. The pelite schist is the main rock type and contains the classic medium pressure metamorphic minerals. The author divided Baoyintu group into five assemblages, investigated the rock association and plotted geological section of each assemblage in this area. Based on the systemically study of structural geology, petrology, geochemistry and mineralogy, the author reconstructs the protolith, sedimentary environment and tectonic evolution, discusses the mesoscopic and microscopic structure, metamorphism, geochemistry characters and the correlation between porphyroblast growth and deformation-metamorphism. There are three phase deformations in the research area: the earliest one occurred as the Baoyintu group deformed and metamorphosed and the main structure pattern is tight fold within layers during the Dl, large scale reversed fold and two phase faults (Fl fault and F2 fault) during the D2, and superimposed fold and F3 fault during D3. The F3 trancate the Wenduermian group of Silurian. The second and third phase deformation are relate to the orogenic event of late period of early Paleozoic. According to the rock association ,characteristics of the rocks and research of geochemistry, we get some information of the sedimentary environment and tectonic evolution of Baoyintu group. The source rocks are a set of terrigenous deposits-volcanic formation which reflect the history of the tectonic setting: stable- active-restable. And there are two sedimentary cycle from first assemblage to fifth assemblage: from first assemblage to fourth assemblage is a course of progression and the fifth assemblage is a start of regression. We also get the information of the P-T-t path by studying petrographies and calculating temperature and pressure. The path is not similiat to any classic type. And the interpretation is different from the traditional opinion. The P-T-t path reflects the dynamic course of convergence and uplift, magma underplating, back-arc extension and convergence of continental margin. Applying the theory of deformation partitioning to this area, the author discuss the relationship between deformation and porphyroblast growth, and get the conclusion of the sequence of deformation and metamorphism. At the first time we measure the distribution of chemical composition within the porphyroblast by XRF, confirm the theory of deformation partitioning quantitative and get new understanding about growth phase of porphyroblast and growth mode of porphyroblast: porphyroblast grow in the manner as "rose flower", the growth is controlled by the deformation. The elements distribution in porphyroblast reflects the growth manner and indicate history of metamorphism and deformation. So, we can deduce the metmorphism and deformation from the elements distribution in porphyroblast.

青岛近岸沉积物中持久性有机污染物多氯萘和多溴联苯醚

对同一样品经索氏抽提、多级复合硅胶层析柱、渗透凝胶层析柱、氧化铝层析柱分离, 利用低分辨率气相色谱-质谱方法对青岛近岸5个表层沉积物和1个贝类样品中的31种多氯萘(PCNs)和21种多溴联苯醚(PBDEs)异构体的含量分布特征、毒性当量浓度及来源进行了研究. 总PCNs和PBDEs最高含量出现在河口处. 总PCNs含量范围为212~1209 pg/g (dw), 以3氯代PCNs为主. 总PBDEs含量范围为117~5510 pg/g (dw). 主要以6-氯以下(含6-氯)为主. 局部来源的PCNs来自垃圾焚烧、燃煤等高温过程. PBDEs则主要来自分子扩散. 除了在河口处受到城市污水污泥的影响之外, 大气沉降是青岛近海PCNs与PBDEs的重要来源. 青岛近岸贻贝中PCNs和PBDEs都相对于沉积物有富集作用. PCNs的总毒性当量浓度均低于PCBs总毒性当量浓度.

红枫湖有机氯污染物的生物地球化学

本研究以红枫湖为主要研究对象，对环境各介质中PCBs和OCPs进行了研究，讨论了理化因素TOC、粒度、SPM、微生物等对于PCBs和OCPs的影响，对各介质中PCBs和OCPs的组成进行了分析，讨论了红枫湖地区PCBs和OCPs的来源，并对其污染水平进行了评价，得到以下几点认识： 1、对红枫湖水体和沉积物的理化性质进行了分析，和洱海进行了对比。湖泊沉积物有机质含量和C/N比值表明红枫湖沉积物有机质主要来源于河流输入和湖泊内部，洱海主要以湖泊内源为主，与后面PCBs和OCPs分析结果相符。湖泊沉积物有机质及DNA呈现同一规律，表层是有机质和DNA的含量较高的区域，表层至底层整体呈逐渐降低的趋势，表明表层是微生物量和活性最高的层段，有机质的降解主要发生在此区域。湖泊沉积物粒度与有机质和DNA变化趋势一致，暗示了有机质的降解过程主要发生在表层，SRI和SRB的分析表明微生物在有机质降解过程中起着至关重要的作用。 2、红枫湖沉积物中7种PCBs的含量范围在3.2～31.6ng/g之间，主要以PCB28和PCB52为主。其中PCB28的含量范围在0.5～4.6ng/g，平均为1.8ng/g， PCB52含量在0.4～28.1ng/g。PCB28和PCB52低氯取代的PCBs占PCBs总量的60%以上。各点沉积物中PCBs的组成基本一致，其含量的变化主要与其输入来源和环境条件相关。沉积物中PCBs随深度整体呈现降低的趋势，但表层含量比次表层低，表明近年PCBs的输入降低。PCBs与TOC和粒径呈现较显著的正相关关系，与其自身的理化性质相关，PCBs具有较高的憎水性，倾向于在颗粒态中分布，也暗示了其来源。 3、红枫湖沉积物中13种OCPs的组成主要以HCHs和DDTs为主。其中HCHs的含量范围1.6～8.9ng/g，平均值为3.2ng/g，沉积物柱均值表现为HW>DB>HE>JJD；DDTs的含量范围在0.9～25.7ng/g，平均值为7.8ng/g，沉积物柱均值表现为HW>HE>DB>JJD。HCHs按其组成来看，以β-HCH和γ-HCH为主，DDTs以p,p’-DDE和p,p’-DDT为主。α-HCH/γ-HCH的比值在范围在0.1~3.0之间，表明HCH在环境中发生了改变，而且林丹的用量高于混合HCHs。DDT/DDE+DDD的比值基本都小于1，暗示DDTs在环境中发生了较长期的变化，β-HCH和p,p’-DDE的高含量也暗示了大气来源可能也是红枫湖地区OCPs的主要来源之一。 4、红枫湖湖水、汇入汇出河流及其周边土壤中PCBs和OCPs的分析，显示PCBs和OCPS在过滤后水中含量较低，主要分配在悬浮颗粒物中，悬浮颗粒物中的PCBs和OCPs组成与周边土壤中的组成基本一致。HCHs和DDTs的组成和α-HCH/γ-HCH、DDT/DDE+DDD的比值暗示水中悬浮颗粒物及其PCBs和OCPs主要来源于周边土壤和大气沉降。 5、 红枫湖后五鱼体内PCBs主要以4～6氯取代的PCBs的同系物为主，OCPs以HCHs和DDTs为主。鱼体内PCBs和OCPs对于水体的富集系数达到102～105。PCBs富集系数随氯取代数目的增加而增加，表明其生物有效性随氯取代数目的增加而增加，高氯取代的PCBs更容易通过食物链在高营养级生物体内富集，对人体造成危害。 6、 大气总悬浮颗粒物TSP中及背景区土壤中PCBs和OCPs的分析，与其它环境介质中结果基本一致。红枫湖地区大气、水、沉积物、生物和土壤各环境介质中PCBs和OCPs的组成基本一致，表明其来源具有一致性。α-HCH/γ-HCH和 DDT/DDE+DDD的值，及β-HCH、p,p’-DDE的高的比例，暗示红枫湖地区OCPs在环境中经历了较长时间的变化，而且大气长距离传输对于该区OCPs和PCBs的来源具有一定的贡献。从各因子的分析可以得出，红枫湖为该地区PCBs和OCPs的汇。 7、我国PCBs和DDTs、HCHs的含量除了典型区外，在国内外都处于较低和中等污染水平，红枫湖地区整体处于较低污染水平。根据Long和Chapman等对沉积物中POPs的评价方法，红枫湖沉积物中PCBs只有一个样品处于ERL和ERM之间，其它都低于ERL值，表明PCBs对生物造成不利影响的可能性较低；DDTs的值大部分处于ERL和ERM值之间，对生物造成不利影响的可能性较大；γ-HCH的值都低于TEC值，对生物的潜在影响较小。

Simultaneous chiral separation using a combinatorial molecular imprinting phase

Molecular imprinting chiral stationary phase against Cbz-L-Serine (Cbz-L-Ser) and Cbz-L-Alaine (Cbz-L-Ala) were prepared utilizing acrylamide + 2-vinylpyridine as combined basic functional monomers. Cross-selectivity was used to obtain simultaneous chiral separations of Cbz-DL-Ser and Cbz-DL-Ala by connecting two columns packed with Cbz-L-Ser and Cbz-L-Ala imprinted chiral stationary phase, respectively.

Oriented growth of MCM-22 zeolite films

MCM-22 zeolite films have been grown with layers vertical to the substrate under hydrothermal synthesis conditions, and characterized by X-ray diffraction and scanning electron microscopy.

Correct identification of polychlorinated biphenyls in temperature-programmed GC with ECD detection

A method has been developed for peak identification of PCBs in GC with ECD detection under different temperature programs and isothermal conditions on two commonly used columns (DB-5 and DB-1701). This was achieved by means of accurate calibration of retention times based on the concept of the relative retention index P-i and retention times of the selected PCB internal standards. The P-i was calculated from the predicted retention times with the database of the retention parameters (A, B) and the migration equations. Through comparison of the calibrated and experimental retention times of PCBs in technical samples, it was shown that the developed method was effective for correct PCB comprehensive, quantitative, congener-specific (CQCS) analyses.

Growth of zeolite KSO1 on calcined kaolin microspheres

Zeolite KSO1 was successfully synthesized on calcined kaolin microspheres (ca. 60-80 mu m) in situ, and characterized by powder X-ray diffraction, scanning electronic microscopy and nuclear magnetic resonance spectroscopy.

Photoelectron spectroscopy of ammonia via a fast predissociative state

We report a study on resonance enhanced multiphoton ionization photoelectron spectroscopy (REMPI-PES) involving the fast predissociative (A) over tilde state of ammonia, using nano- and femtosecond lasers. The multiphoton scheme involves (1 + 1), (2 + 2), (2 + 2) + 1 and (2 + 2) + 2 photon processes. We have found a progression of stretching vibrations nu(1) in the PE spectrum when pumping NH3 (A) over tilde upsilon(2) = 0, 1 and 3 as intermediate states. The stretching vibration intensity distributions in the photoelectron spectrum are calculated by using the Chebychev method of the wavepacket propagation. The femtosecond spectrum shows a similar feature to the nanosecond spectrum. However, high laser power also causes band broadening and shifting effect as well as above threshold multiphoton ionization.

A practical approach to the degradation of polychlorinated biphenyls in transformer oil

A practical and efficient disposal method for hydrodechlormation of polychlorinated biphenyls (PCBs) in transformer oil is reported. Transformer oil containing PCBs was treated by nanometric sodium hydride (nano-NaH) and transition metal catalysts. High destruction and removal efficiency (89.8%) can be attained by nano-NaH alone under mild conditions. The process exhibits apparent characteristics of a first order reaction. The reductive ability of nano-NaH was enhanced by the addition of transition metal catalysts. In the presence of TiCl4, 99.9% PCBs was hydrodechlorinated. The complex reducing reagents, Ni(OAc)(2) + i-PrONa, show extra hydrodechlorinating activity for di-chlorinated biphenyls. (c) 2004 Elsevier Ltd. All rights reserved.

Reversible regeneration of molybdenum carbonyl species on an alumina thin film

The thin alumina film-supported metallic molybdenum model catalyst was prepared by thermal decomposition of MO(CO)6, and CO chemisorption on the catalyst was investigated in-situ by thermal desorption spectroscopy (TDS) and X-ray photoelectron spectroscopy (XPS). The results showed that a molybdenum-carbonyl-like species was formed on the alumina surface at low temperature by high coordination of CO with the surface metallic molybdenum nanoparticles, indicating a reversible regeneration of molybdenum carbonyl on the alumina surface. CO chemisorption on the model catalyst surface caused the Mo 3d XPS peak to shift toward higher binding energy. The formed molybdenum carbonyl species appeared at about 240 K in the TDS. The supported metallic molybdenum nanoparticles were quite different from the bulk molybdenum in chemical properties, which indicated a prominent particle-size effect of the clusters.

Saying isn't necessarily believing: influencing self-theories in computing

Simon, B., Hanks, B., Murphy, L., Fitzgerald, S., McCauley, R., Thomas, L., and Zander, C. 2008. Saying isn't necessarily believing: influencing self-theories in computing. In Proceeding of the Fourth international Workshop on Computing Education Research (Sydney, Australia, September 06 - 07, 2008). ICER '08. ACM, New York, NY, 173-184.

Influence of blood donation on O-2 uptake on-kinetics, peak O-2 uptake and time to exhaustion during severe-intensity cycle exercise in humans

Thatcher, Rhys, et al., 'Influence of blood donation on O-2 uptake on-kinetics, peak O-2 uptake and time to exhaustion during severe-intensity cycle exercise in humans', Experimental Physiology (2006) 91(3) pp.499-509 RAE2008