Growth of all-carbon horizontally aligned single-walled carbon nanotubes nucleated from fullerene-based structures

All-carbon single-walled carbon nanotubes (SWCNTs) were successfully synthesized, nucleated using a fullerene derivative. A systematic investigation into the initial preparation of C₆₀ fullerenes as growth nucleators for the SWCNTs was conducted. Enhancement in the yield of the produced SWCNT has been achieved with exploring different dispersing media for the fullerenes, the period, and environment of the initial thermal treatment of the fullerenes in addition to the use of different fullerene-based structures. The systematic studies significantly advance our understanding of the growth of the all-carbon catalyst-free single-walled carbon nanotubes. Field-effect transistors were fabricated using the catalyst-free SWCNT and then electrically characterized, showing current capacity as high as the well-studied catalyst-assisted nanotubes.     

Approximate syllogisms – on the logic of everyday life

Since Aristotle it is recognised that a valid syllogism cannot have two particular premises. However, that is not how a lay person sees it; at least as long as the premises read many, most etc, instead of a plain some. The lay people are right if one considers that these syllogisms do not have strict but approximate (Zadeh) validity. Typically there are only particular premises available in everyday life and one is dependent on such syllogisms. – Some rules on the usage of particular premises are given below.     

In situ spectroelectrochemistry of poly(N,N'-ethylenebis(salicylideneiminato)Cu(II))

In situ ESR, UV-visible, and FT-IR-ATR spectroelectrochemistry were used to study the charge transfer for electrochemically synthesized poly(N,N'-ethylenebis(salicylideneiminato)Cu(II)), which represents a macromolecular metal chelate with ESR-active central metal ions. Structural evidence for different charged states in electroactive poly(Cu(II)-salen) was obtained from ESR, UV-visible, and FT-IR spectra under reversible redox cycling. The changes in a characteristic broad ESR line without hyperfine splitting originating from Cu(II) as well as in the corresponding UV-visible and infrared spectra are discussed in order to describe an electron transfer to the redox-active sites within the polymer chains in detail.     

Microfabricated system for parallel single-cell capillary electrophoresis

Performing single-cell electrophoresis separations using multiple parallel microchannels offers the possibility of both increasing throughput and eliminating cross-contamination between different separations. The instrumentation for such a system requires spatial and temporal control of both single-cell selection and lysis. To address these problems, a compact platform is presented for single-cell capillary electrophoresis in parallel microchannels that combines optical tweezers for cell selection and electromechanical lysis. Calcein-labeled acute myloid leukemia (AML) cells were selected from an on-chip reservoir and transported by optical tweezers to one of four parallel microfluidic channels. Each channel entrance was manufactured by F2-laser ablation to form a 20- to 10-microm tapered lysis reservoir, creating an injector geometry effective in confining the cellular contents during mechanical shearing of the cell at the 10-microm capillary entrance. The contents of individual cells were simultaneously injected into parallel channels resulting in electrophoretic separation as recorded by laser-induced fluorescence of the labeled cellular contents.     

Simulation-based optimization of personnel assignment planning in sequenced commercial vehicle assembly: A software tool for iterative improvement

This paper presents a simulation-based planning software for high complexity production settings which currently undergoes first real-data industry application tests in commercial vehicle assembly. The system will also be applicable in other industries with a sufficiently high number of products and variants. The solution enables the forecasting of required personnel and temporary additional workers (“floaters”) for every cycle at the production line. It periodically collects process times, sequence and feature data for the vehicles. The cumulated workload is calculated under consideration of flexibilities. A web-based user interface enables to set and change reference data, define process simulations and to compile diagrams and charts for the analysis of the results of the different simulation runs. Various filters as to time periods, vehicle types or feature variants allow the planner a target-oriented analysis and provide feedback for improving production line tacting. Finally, some qualitative results of a first industry test in commercial vehicle assembly give feedback about the usability of existing analytical features and desirable additional features.     

Fault detection and isolation in manufacturing systems with an identified discrete event model

In this article a generic method for fault detection and isolation (FDI) in manufacturing systems considered as discrete event systems (DES) is presented. The method uses an identified model of the closed-loop of plant and controller built on the basis of observed fault-free system behaviour. An identification algorithm known from literature is used to determine the fault detection model in form of a non-deterministic automaton. New results of how to parameterise this algorithm are reported. To assess the fault detection capability of an identified automaton, probabilistic measures are proposed. For fault isolation, the concept of residuals adapted for DES is used by defining appropriate set operations representing generic fault symptoms. The method is applied to a case study system.     

Work-hardening stages of AA1070 and AA6060 after severe plastic deformation

Based on the concept of work-hardening for fcc metals, the commercially pure aluminum AA1070 (soft annealed) and the aluminum alloy AA6060 (peak-aged) were investigated. Equal-channel angular pressing (ECAP) was used to introduce very high strains and an ultrafine-grained microstructure. Compression tests were performed in a wide range of strain rates between 10⁻⁴ and 10³ s⁻¹ subsequently. The results show that strain path and the corresponding dislocation structure are important for the post-ECAP yielding and the following hardening response. Furthermore, the precipitates of the alloy clearly constrain the interactions of dislocations in work-hardening stage III—causing lower strain rate sensitivity and retarding the process of grain refinement as well. If compared to the pure aluminum, the precipitates avoid hardening in stage V where an additional rate and temperature-dependent effect contributes—supposedly caused by the interaction of deformation-induced vacancies and dislocations.     

Anomalous Dispersion of LO Phonons inLa.1.85Sr0.15CuO4

The dispersion of the highest energy LO phonon branch in La. _1.85 Sr _0.15 CuO ₄ in the (100) direction has been reinvestigated by high resolution inelastic neutron scattering. In contrast to what has been recently reported by McQueeney et al. (Phys. Rev. Lett. 82. , 628 (1999)), we find that the dispersion is continuous throughout the Brillouin zone. These results are in conflict with the idea of charge stripe order existing on a time scale which is long compared to that of the LO frequencies. On the other hand, the strong softening and boradening of LO phonons observed on doping might be taken as a precursor phenomenon to a stripe order phase with a periodicity of about 4 lattice constants. also at