bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust diagnosis and fault‐tolerant control of distributed processes over communication networks
Authors: Ghantasala Sathyendra , El‐Farra Nael H. 
Published: September 2008

AbstractThis paper develops a robust fault detection and isolation (FDI) and fault‐tolerant control (FTC) structure for distributed processes modeled by nonlinear parabolic partial differential equations (PDEs) with control constraints, time‐varying uncertain variables, and a finite number of sensors that transmit their data over a communication network. The network imposes limitations on the accuracy of the output measurements used for diagnosis and control purposes that need to be accounted for in the design methodology. To facilitate the controller synthesis and fault diagnosis tasks, a finite‐dimensional system that captures the dominant dynamic modes of the PDE is initially derived and transformed into a form where each dominant mode is excited directly by only one actuator. A robustly stabilizing bounded output feedback controller is then designed for each dominant mode by combining a bounded Lyapunov‐based robust state feedback controller with a state estimation scheme that relies on the available output measurements to provide estimates of the dominant modes. The controller synthesis procedure facilitates the derivation of: (1) an explicit characterization of the fault‐free behavior of each mode in terms of a time‐varying bound on the dissipation rate of the corresponding Lyapunov function, which accounts for the uncertainty and network‐induced measurement errors and (2) an explicit characterization of the robust stability region where constraint satisfaction and robustness with respect to uncertainty and measurement errors are guaranteed. Using the fault‐free Lyapunov dissipation bounds as thresholds for FDI, the detection and isolation of faults in a given actuator are accomplished by monitoring the evolution of the dominant modes within the stability region and declaring a fault when the threshold is breached. The effects of network‐induced measurement errors are mitigated by confining the FDI region to an appropriate subset of the stability region and enlarging the FDI residual thresholds appropriately. It is shown that these safeguards can be tightened or relaxed by proper selection of the sensor spatial configuration. Finally, the implementation of the networked FDI–FTC architecture on the infinite‐dimensional system is discussed and the proposed methodology is demonstrated using a diffusion–reaction process example. Copyright © 2008 John Wiley & Sons, Ltd.
Motility of Metal Nanoparticles in Silicon and Induced Anisotropic Silicon Etching
Authors: Peng Kuiqing , Lu Aijiang , Zhang Ruiqin , Lee Shuit‐Tong 
Published: September 2008

AbstractThe autonomous motion behavior of metal particles in Si, and the consequential anisotropic etching of silicon and production of Si nanostructures, in particular, Si nanowire arrays in oxidizing hydrofluoric acid solution, has been systematically investigated. It is found that the autonomous motion of metal particles (Ag and Au) in Si is highly uniform, yet directional and preferential along the [100] crystallographic orientation of Si, rather than always being normal to the silicon surface. An electrokinetic model has been formulated, which, for the first time, satisfactorily explains the microscopic dynamic origin of motility of metal particles in Si. According to this model, the power generated in the bipolar electrochemical reaction at a metal particle's surface can be directly converted into mechanical work to propel the tunneling motion of metal particles in Si. The mechanism of pore and wire formation and their dependence on the crystal orientation are discussed. These models not only provide fundamental interpretation of metal‐induced formation of pits, porous silicon, and silicon nanowires and nanopores, they also reveal that metal particles in the metal/Si system could work as a self‐propelled nanomotor. Significantly, it provides a facile approach to produce various Si nanostructures, especially ordered Si nanowire arrays from Si wafers of desired properties.
Connective‐Tissue Fibroblasts Established on Micropillar Interfaces are Pivotal for Epithelial‐Tissue Morphogenesis
Authors: Mussig Eva , Steinberg Thorsten , Schulz Simon , Spatz Joachim P. , Ulmer Jens , Grabe Niels , Kohl Annette , Komposch Gerda , Tomakidi Pascal 
Published: September 2008

AbstractPolydimethylsiloxane (PDMS) pillar arrays are applied as a biomechanical microenvironment to establish gingival connective‐tissue fibroblasts (GCTFs) and to further analyze the pivotal role of GCTFs in epithelial‐tissue morphogenesis. GCTFs are known to exert successful adhesion and growth on fibronectin immobilized on pillar heads, over time, concomitant with the increased gene expression of vimentin and collagen type‐I. GCTF‐populated pillar arrays clearly reveal that epithelial‐tissue morphogenesis of immortalized human gingival keratinocytes (IHGKs), co‐cultured for 7 and 14 days, parallels the in vivo phenotype more closely, when compared with GCTF‐free control arrays. This in vivo‐like phenotype is substantiated by higher mRNA levels for keratin 1, involucrin and filaggrin differentiation markers. Furthermore, it is reflected by a tissue‐specific protein orientation of the aforementioned molecules, and also of the cell‐to‐cell contact forming desmoplakin and the basement membrane constituents, laminin‐5, laminin‐1/10, and collagen type‐IV. These experiments suggest that the in vivo‐like phenotype of the IHGK is governed by the GCTFs growing on the micropillar interfaces. Moreover, they form the basis for the optimization or neogeneration of biomaterials by varying predefined microenvironmetal parameters to achieve an in vivo‐like cell growth and differentiation, indispensable for tissue morphogenesis during regeneration.
Diffusion Controlled and Temperature Stable Microcapsule Reaction Compartments for High‐Throughput Microcapsule‐PCR
Authors: Mak Wing Cheung , Cheung Kwan Yee , Trau Dieter 
Published: September 2008

AbstractA novel approach to perform a high number of individual polymerase chain reactions (PCR) in microcapsule reaction compartments, termed “Microcapsule‐PCR” was developed. Temperature stable microcapsules with a selective permeable capsule wall were constructed by matrix‐assisted layer‐by‐layer (LbL) Encapsulation technique. During the PCR, small molecular weight building blocks – nucleotides (dNTPs) were supplied externally and diffuse through the permeable capsule wall into the interior, while the resulted high molecular weight PCR products were accumulated within the microcapsule. Microcapsules (∼110.8 µm average diameter) filled with a PCR reaction mixture were constructed by an emulsion technique having a 2% agarose core and a capsule formed by LbL coating with poly(allylamine‐hydrochloride) and poly(4‐styrene‐sulfonate). An encapsulation efficiency of 47% (measured for primer‐FITC (22 bases)) and 98% PCR efficiency was achieved. Microcapsules formed by eight layers of polyelectrolyte and subjected to PCR cycling (up to 95 °C) demonstrated good temperature stability without any significantly changes in DNA retention yield and microcapsule morphology. A multiplex Microcapsule‐PCR experiment demonstrated that microcapsules are individual compartment and do not exchange templates or primers between microcapsules during PCR cycling.
Organic‐Oxide Cathode Buffer Layer in Fabricating High‐Performance Polymer Light‐Emitting Diodes
Authors: Lee Tsung‐Hsun , Huang Jung‐Chun‐Andrew , Pakhomov Georgi L'vovich , Guo Tzung‐Fang , Wen Ten‐Chin , Huang Yi‐Shun , Tsou Chuan‐Cheng , Chung Chia‐Tin , Lin Ying‐Chang , Hsu Yao‐Jane 
Published: September 2008

AbstractSpin‐casting or thermal evaporation in vacuum of a salt‐free, neutral, organic‐oxide ultra‐thin film as a buffer layer with an aluminum (Al) cathode has become an alternative approach for fabricating high‐performance organic and polymer light‐emitting diodes (O/PLEDs). [Guo et al., Appl. Phys. Lett. 2006, 88, 113501 and Appl. Phys. Lett. 2006, 89, 053507] The electroluminescence efficiency of phenyl‐substituted poly(para‐phenylene vinylene) copolymer‐based PLEDs is 0.16 cd A−1 when Al is used as the device cathode, but is approximately two orders of magnitude higher, 14.53 cd A−1, when an organic oxide/Al composite cathode is used. The polymer/metal junction in PLEDs with and without depositing an ultra‐thin organic oxide interlayer is studied by X‐ray photoelectron spectroscopy. Experimental results indicate that the deposition of an Al electrode causes the oxidation at the surface of the light‐emissive polymer layer. Introducing an organic‐oxide cathode buffer layer suppresses the oxidation and the diffusion of the Al atoms into the functional polymer layer. The formation of a carbide‐like (negative carbon) thin layer, which accompanies interfacial interactions, is critical to the injection of electrons through the Al cathode. The balanced charge injection is responsible for the substantially improved device performance. This process is specific to the organic oxide/Al interface, as revealed by a comparison with similar device configurations that have Ag as the electrode, in which no significant interaction in the interface is observed.
Surfactant‐Free, Self‐Assembled PVA‐Iron Oxide/Silica Core–Shell Nanocarriers for Highly Sensitive, Magnetically Controlled Drug Release and Ultrahigh Cancer Cell Uptake Efficiency
Authors: Hu Shang‐Hsiu , Liu Dean‐Mo , Tung Wei‐Lin , Liao Chen‐Fu , Chen San‐Yuan 
Published: September 2008

AbstractSurfactant‐free, self‐assembled iron oxide/silica core–shell (SAIO@SiO2) nanocarriers were synthesized as bifunctional magnetic vectors that can be triggered for the controlled release of therapeutic agents by an external magnetic field. In addition, drug release profiles can be well‐regulated through an ultrathin layer of silica shell. The hydrophobic drug molecules were encapsulated within the iron oxide‐PVA core and then further covered with a thin‐layer silica shell to regulate the release pattern. Remote control of drug release from the SAIO@SiO2 nanocarriers was achieved successfully using an external magnetic field where the core phase being structurally disintegrated to a certain extent while subjected to magnetic stimulus, resulting in a burst release of the encapsulated drug. However, a relatively slow and linear release restored immediately, directly after removal of the stimulus. The nanostructural evolution of the nanocarriers upon the stimulus was examined and the mechanism for controlled drug release is proposed for such a core–shell nanocarrier. Surprisingly, the surfactant‐free SAIO@SiO2 nanocarriers demonstrated a relatively high uptake efficiency from the HeLa cell line. Together with a well‐regulated controlled release design, the nanocarriers may provide great advantages as an effective cell‐based drug delivery nanosystem for biomedical applications.
Growth, Cathodoluminescence and Field Emission of ZnS Tetrapod Tree‐like Heterostructures
Authors: Chen Zhi‐Gang , Zou Jin , Liu Gang , Yao Xiangdong , Li Feng , Yuan Xiao‐Li , Sekiguchi Takashi , Lu Gao Qing , Cheng Hui‐Ming 
Published: September 2008

AbstractWe report the growth mechanism, cathodoluminescence and field emission of dual phase ZnS tetrapod tree‐like heterostructures. This novel heterostructures consist of two phases: zinc blende for the trunk and hexagonal wurtzite for the branch. Direct evidence is presented for the polarity induced growth of tetrapod ZnS trees through high‐resolution electron microscopy study, demonstrating that Zn‐terminated ZnS (111)/(0001) polar surface is chemically active and S‐terminated (${\bar 1}$${\bar 1}$${\bar 1}$)/(000$\bar 1$) polar surface is inert in the growth of tetrapod ZnS trees. Two strong UV emissions centered at 3.68 and 3.83 eV have been observed at room temperature, which are attributed to the bandgap emissions from the zinc blende trunk and hexagonal wurtzite branch, indicating that such structures can be used as unique electromechanical and optoelectronic components in potential light sources, laser and light emitting display devices. In addition, the low turn‐on field (2.66 Vµm−1), high field‐enhancement factor (over 2600), large current density (over 30 mAcm−2 at a macroscopic field of 4.33 Vµm−1) and small fluctuation (∼1%) further indicate the availability of ZnS tetrapod tree‐like heterostructures for field emission panel display. This excellent field‐emission property is attributed to the specific crystallographic feature with high crystallinity and cone‐shape patterned branch with nanometer‐sized tips. Such a structure may optimize the FE properties and make a promising field emitter.
Enhancement and Concurrence of Emissions from Multiple Fluorophores in a Single Emitting Layer of Micellar Nanostructures
Authors: Yoo Seong Il , Lee Jae‐Hyun , Sohn Byeong‐Hyeok , Eom Intae , Joo Taiha , An Sung Jin , Yi Gyu‐Chul 
Published: September 2008

AbstractFor concurrent emission of multiple fluorophores from a single emitting layer with a highly efficient energy transfer from antenna molecules to emitting molecules by fluorescence resonance energy transfer (FRET), a paradoxical requirement in an emitting layer is necessary, that is, close placement of an emitting fluorophore and a harvesting molecule, and isolation of emitting fluorophores. Here we demonstrate how to overcome this paradox by full utilization of a micellar nanostructure consisting of a core and a corona, that is, the core is used as a place for FRET between light‐collecting donors and light‐emitting fluorophores, and the corona is used as a barrier for FRET between light‐emitting fluorophores. Enhancement of light emission from fluorophores was achieved by locating emitting fluorophores and light‐harvesting molecules at the same core of micelles. Moreover, with the same micellar nanostructure, concurrent emission of multiple fluorophores with enhanced intensity was induced by isolating them in independent micelles, the corona structure of which worked as an effective blockade for FRET.
Protein–Polymer Hybrid Amphiphiles
Authors: Dirks A. (Ton) J. , Nolte Roeland J. M. , Cornelissen Jeroen J. L. M. 
Published: September 2008

AbstractBiohybrid amphiphiles composed of a protein head group and a hydrophobic polymer tail self‐assemble in water in a similar way as low molecular weight surfactants. Owing to the presence of the protein, biohybrid amphiphiles, and their assemblies, however, hold the additional feature of a built‐in (bio)functionality. These compounds therefore are promising building blocks for the synthesis of functional nanometer‐sized materials. We discuss recent advances in the relatively young field of protein–polymer hybrid amphiphiles, which so far mainly involved exploratory and fundamental studies providing a conceptual basis for the development of more complex systems with interesting applications in the future.magnified image
Halbleiterquantenpunkte für die Bioanalyse
Authors: Gill Ron , Zayats Maya , Willner Itamar 
Published: September 2008

AbstractHalbleiternanopartikel (oder Halbleiterquantenpunkte) verfügen über einzigartige photophysikalische Eigenschaften (z. B. eine größenabhängige Fluoreszenz), zeigen hohe Fluoreszenzquantenausbeuten und sind gegen photochemische Zersetzung stabil. Dies ermöglicht ihre Verwendung als Markierungen für die optische Parallelanalyse von Immunkomplexen und DNA‐Hybridisierungen oder zur Verfolgung katalytischer biochemischer Umwandlungen. So können die Replizierung oder Telomerisierung von Nucleinsäuren, die Oxidation von Phenolderivaten durch Tyrosinasen oder die Hydrolyse von Peptiden durch Proteasen anhand des resonanten Fluoreszenzenergietransfers oder des lichtinduzierten Elektronentransfers analysiert werden. Durch Photoanregung von Quantenpunkt‐Biomolekül‐Hybriden, die mit Elektroden verbunden sind, gelingt die photoelektrochemische Übersetzung biologischer Erkennungsprozesse oder katalytischer Umwandlungen. Beispiele sind die Erzeugung eines Photostroms durch CdS‐Nanopartikel, die über DNA‐Doppelstränge mit einer Elektrode verknüpft sind, oder das Auftreten von Photoströmen als Folge biochemischer Umwandlungen. Beim elektrochemischen DNA‐ oder Protein‐Nachweis binden mit Nucleinsäuren oder Proteinen funktionalisierte Halbleiternanopartikel an biologische Komplexe. Nach der anschließenden Zersetzung der Nanopartikel lassen sich die Ionen nachweisen, und der Erkennungsprozess wird offenkundig.
Alles begann mit einem Irrtum: Die Nomofungin/Communesin‐Story
Authors: Siengalewicz Peter , Gaich Tanja , Mulzer Johann 
Published: September 2008

AbstractDie Communesin/Nomofungin/Perophoramidin‐Story ist ein eindrucksvolles Beispiel dafür, wie biogenetische Überlegungen falsche Strukturzuordnungen korrigieren und Synthesechemiker zu neuen fruchtbaren Überlegungen inspirieren können. Nach intensiven Bemühungen anderer Arbeitsgruppen, die in der Totalsynthese von Perophoramidin durch Funk im Jahr 2004 gipfelten, gelang Qin et al. 2007 die erste Totalsynthese eines Communesins.
Postsynthetische DNA‐Modifizierung mithilfe der kupferkatalysierten Azid‐Alkin‐Cycloaddition
Authors: Gramlich Philipp M. E. , Wirges Christian T. , Manetto Antonio , Carell Thomas 
Published: September 2008

AbstractDie Markierung von DNA ist von größter Bedeutung für die Biomedizin und bildet die Basis für die Konstruktion DNA‐basierter funktionaler Nanomaterialien. Seit kurzem zählt die Kupfer(I)‐katalysierte Huisgen‐Cycloaddition von Aziden mit Alkinen (CuAAC) zum Repertoire der DNA‐Markierungsmethoden. Diese Methode ermöglicht die Modifizierung von DNA mit beispielloser Effizienz. Nicht nur kleine Oligonucleotide, sondern auch ganze Genfragmente können so hochgradig chemisch modifiziert werden. Die CuAAC‐Reaktion liefert die markierten Polynucleotide, meist nach einfacher Ausfällung, in ausgezeichneter Reinheit und ist auf dem besten Wege, die Synthese funktionalisierter DNA‐Stränge zu revolutionieren. Die Methode wird von entscheidender Bedeutung für die Erzeugung neuer diagnostischer Systeme und für die nanotechnologische Forschung sein.
Tip‐Enhanced Near‐Field Optical Microscopy
Authors: Hartschuh Achim 
Published: September 2008

AbstractSpectroscopic methods with high spatial resolution are essential for understanding the physical and chemical properties of nanoscale materials, including quantum structures and biological surfaces. An optical technique is reviewed that relies on the enhanced electric fields in the proximity of a sharp, laser‐irradiated metal tip. These fields are utilized for spatially confined probing of various optical signals, thus allowing for a detailed sample characterization far below the diffraction limit. In addition, tip‐enhanced fields also provide the sensitivity crucial for the detection of nanoscale volumes. After outlining the principles of near‐field optics, the mechanisms contributing to local field enhancement and how it can be used to enhance optical signals are discussed. Different experimental methods are presented and several recent examples of Raman and fluorescence microscopy with 10 nm spatial resolution of single molecules are reviewed.
Recycled PCB flour reinforced linear low‐density polyethylene composites enhanced by water cross‐linking reaction
Authors: Kuan Chen‐Feng , Kuan Hsu‐Chiang , Ma Chen‐Chi M. , Chen Chia‐Hsun , Lin Kun‐Chang , Peng Hsin‐Chin 
Published: September 2008

AbstractRecycled printed circuit board (PCB) flour reinforced linear low‐density polyethylene (LLDPE) composites were prepared successfully. Water cross‐linking technique was adopted to improve the physical characteristics of the composites. Composites were compounded using a twin‐screw extruder and treated with a coupling agent (vinyltrimethoxysilane, VTMOS) and a compatibilizer (polyolefin elastomer grafted with melaic acid, POE‐g‐MA). They were then moisture‐cross‐linked in hot water. The composite that was cross‐linked in water exhibited better mechanical properties than the noncross‐linked composite because of strong chemical bonding between the filler and the polyolefin matrix. When the PCB flour content reaches 60 wt% following 4 h of water cross‐linking, the tensile strength and the flexural strength are increased by 18.8% (12.8–15.2 MPa) and 13.2% (21.9–24.8 MPa) respectively. Scanning electron microscopy (SEM) images of the fracture surfaces of water cross‐linked composites indicated that good interfacial strength existed between the filler and the polyolefin matrix. Thermal analyses of water cross‐linked composites indicated that the thermal degradation temperature and the heat deflection temperature (HDT) of the composite increased with the increasing of water cross‐linking time. The HDT of the composite rose from 55.8 to 83 °C. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
Influence of a pore‐former and PTFE in the performance of the direct ethanol fuel cell
Authors: Biswas S. K. , Sambu P. , Basu S. 
Published: September 2008

AbstractThe direct ethanol fuel cell (DEFC) is a promising fuel cell device, which could provide power to portable and microelectronic equipment in the future. In the present investigation, the influence of a pore‐former, polytetrafluoroethylene (PTFE) and catalyst loadings in the electrocatalyst of the anode on DEFC performance is studied. The decal transfer method is used to prepare the membrane electrode assembly (MEA) using PtRu/C (40:20% by wt) as the anode catalyst, and Pt/C (40% by wt) as the cathode catalyst, a pore‐former, PTFE dispersion and Nafion ionomer. The pore‐former used is 10% (by wt) NaHCO3 in the catalyst ink during the preparation of MEA. The voltage‐current characteristics of DEFC were monitored at different loadings of the catalyst, PTFE and a pore‐former in MEA. The DEFC performance improved with the use of a pore‐former and higher loading of PTFE in MEA. Higher DEFC performance is obtained because PTFE, along with the network of pores in the anode side allowed easy removal of reaction species, thereby rendering the catalyst site available for ethanol oxidation. Further, the use of a pore‐former and PTFE at the anode allowed higher loading of electrocatalyst resulting in an increase in the performance of DEFC. The DEFC, with 1 mg cm−2 of catalyst loading at the anode and cathode, 10% (by wt) NaHCO3 of a pore‐former, 20% (by wt) PTFE loading in catalyst ink gives maximum power density of 8.5 mW cm−2 at a current density of 31.3 mA cm−2. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
Steady‐state target calculation for constrained predictive control systems based on goal programming
Authors: Li Shaoyuan , Zheng Yi , Wang Baiping 
Published: September 2008

AbstractA new method of steady‐state target calculation for constrained model predictive control (MPC) using goal programming has been developed to solve the problem that the result is not satisfactory when the optimization problem is infeasible or the feasible region is away from the desired working point owing to system dynamics. In this model, soft constraints adjustment and target relaxation have been adopted simultaneously to coordinate with the result. The goal priority factors are introduced to describe the priority of constraints and targets; thereby, the steady‐state target calculation is transformed into a goal‐programming problem with a standard linear programming form and is solved with some calculation in real time. Simulation is processed with the example of the Shell heavy oil fractionators' benchmark problem, and the result shows the validity of the proposed algorithm. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.