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141.
Robert Burger Patrick Reith Victor Akujobi Jens Ducrée 《Microfluidics and nanofluidics》2012,13(4):675-681
This work presents a novel magnetic actuation scheme for advanced particle handling on our previously introduced, centrifugal microfluidic platform for array-based analysis of individual cells and beads. The conceptually simple actuation is based on the reciprocating motion of an elastomeric membrane featuring an integrated permanent magnet and a stationary magnet aligned along the orbit of a disc-based chamber. This compression chamber is placed at the downstream end of the particle capture chamber to induce centripetally directed, hydrodynamic lift forces on particles trapped in V-shaped geometrical barriers. Towards high frequencies of rotation, the on-disc magnet ceases to follow the rapidly oscillating magnetic field, so that the magnetic actuator is disabled during the initial, sedimentation-based filling of the trap array. At reduced spin speeds, the residence time of the magnetic actuator is sufficient to displace the magnetic actuator, resulting in a flow through the V-cup array that re-distributes, and eventually fully depletes, the previously trapped beads from the array. The same magnetic deflection scheme is also demonstrated to accelerate mixing, e.g. for upstream sample preparation. 相似文献
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143.
By mapping the small-angle X-ray scattering (SAXS) from a looped poly-(para-phenylene terephtalamide) (aramid, PPTA) filament using a synchrotron X-ray microbeam, we investigate the effects of axially compressive and tensile strain on internal fibrillar structures. Unique observations of oscillations in the highly anisotropic SAXS patterns indicate a regular internal structure. Upon increase of the applied compressive strain, a significant decrease in oscillation frequency is observed in the scattering pattern. With an increase in imposed tensile strain an increase in oscillation frequency in the scattering pattern is observed. One model capable of describing the intensity is a model of stacked cylinders. These cylinders could be part of the fibrillar structure present in the PPTA fibres, which consist of cylinder- to tape-like objects, the presence of which is supported by SEM images. One hypothetical physical interpretation presented here for the appearance of a regular internal structure is the occurrence of fibrillar separation in regions undergoing axially compressive strain, and the appearance of strain relief/slip planes between packs of fibrils in regions undergoing tensile strain. Compaction of these packs upon increase of tensile strain could increase the repetition distance in the structure as multiple packs combine to form a single pack. 相似文献
144.
Elmar Strassburger Thomas Hutzler Jens Klimke 《Journal of the American Ceramic Society》2013,96(9):2718-2721
Contrary to the moderate ballistic advantage of Al2O3 ceramics over MgAl2O4 polycrystals, the present study shows a reverse ratio of the ballistic strength of alumina and spinel single crystals: Spinel single crystals outperform sapphire and exhibit a similarly high stability as submicrometer Al2O3 ceramics. The results correlate with different cleavage of single crystalline spinel and sapphire, changing the fragmentation on ballistic impact. 相似文献
145.
Three types of 1,4-diazabutadiene stabilized low-valent iridium complexes, namely [IrCl(cod)(MesDAB)] (1), [IrCl(coe)(MesDAB)] (2) and [IrCl(MesDAB)2] (3), have been prepared from 1,4-bis(2,4,6-trimethylphenyl)-1,4-diaza-1,3-butadiene (MesDAB) and [IrCl(cod)]2 or [IrCl(coe)2]2, respectively. The complexes have been investigated by NMR spectroscopy and X-ray diffraction experiments. While tetra-coordinated 2 and penta-coordinated 3 maintain their solid state structure in solution, penta-coordinated 1 shows fluxional behavior. The crystal structures determined indicate strong π-backbonding towards the MesDAB ligand in all cases. 相似文献
146.
147.
Future Scenarios: What are the Future Services and Applications? 总被引:1,自引:1,他引:0
Christian Kloch Jens Enevold Kristensen Bent Bilstrup 《Wireless Personal Communications》2010,53(3):315-327
With the change of paradigm within user-machine interaction, there is an increasing demand for seamless interoperability between
different technologies as well as more intuitive ways of utilizing the applications on the devices. This implies that the
underlying technologies must support the appropriate bandwidth, mobility and quality at the right cost in order for the end-user
to perceive the infrastructure appropriate for the services and corresponding applications of the future. In addition, it
is required that interoperability will be realized at the semantic level and not just the syntactical level. The purpose of
the paper is to present the authors’ thoughts of a new Information and Communication Technology paradigm and to highlight
what might have an impact on the realization/deployment of such a paradigm. 相似文献
148.
149.
Personality and social relationships were assessed twice across a 4-year period in a general population sample of 489 German young adults. Two kinds of personality–relationship transaction were observed. First, mean-level change in personality toward maturity (e.g., increase in Conscientiousness and decrease in Neuroticism) was moderated by the transition to partnership but was independent of other developmental transitions. Second, individual differences in personality traits predicted social relationships much better than vice versa. Specifically, once initial correlations were controlled for, Extraversion, Shyness, Neuroticism, self-esteem, and Agreeableness predicted change in various qualities of relationships (especially with friends and colleagues), whereas only quality of relationships with preschool children predicted later Extraversion and Neuroticism. Consequences for the transactional view of personality in young adulthood are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
150.
The topic of this paper is minimum cost operative planning of pressurized water supply networks over a finite horizon and
under reliable demand forecast. Since this is a very hard problem, it is desirable to employ sophisticated mathematical algorithms,
which in turn calls for carefully designed models with suitable properties. The paper develops a nonlinear mixed integer model
and a nonlinear programming model with favorable properties for gradient-based optimization methods, based on smooth component
models for the network elements. In combination with further nonlinear programming techniques (Burgschweiger et al. in ZIB
Report ZR-05-31, Zuse Institute Berlin, 2005), practically satisfactory near-optimum solutions even for large networks can be generated in acceptable time using standard
optimization software on a PC workstation. Such an optimization system is in operation at Berliner Wasserbetriebe. 相似文献