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81.
82.
Henrik Schulz 《Discrete Applied Mathematics》2009,157(16):3485-3493
In this paper we introduce an algorithm for the creation of polyhedral approximations for certain kinds of digital objects in a three-dimensional space. The objects are sets of voxels represented as strongly connected subsets of an abstract cell complex. The proposed algorithm generates the convex hull of a given object and modifies the hull afterwards by recursive repetitions of generating convex hulls of subsets of the given voxel set or subsets of the background voxels. The result of this method is a polyhedron which separates object voxels from background voxels. The objects processed by this algorithm and also the background voxel components inside the convex hull of the objects are restricted to have genus 0. The second aim of this paper is to present some practical improvements to the discussed convex hull algorithm to reduce computation time. 相似文献
83.
Per Helvig Christensen Steen Mørup Henrik Topsøe Bjerne Steffen Clausen 《Hyperfine Interactions》1986,28(1-4):945-948
Bimetallic Fe-Co alloy catalysts supported on silica have been studied by use of combined Mössbauer absorption and emisson spectroscopy. Effects of carburization on samples with different particle size are discussed. 相似文献
84.
85.
Henrik Ramsay 《欧洲无机化学杂志》1909,42(1):1137-1140
86.
Management review of the quality-management system is an item in many quality standards and a requirement of the ISO 9001:2000
standard and of laboratory standards ISO 15189 and ISO 17125, and others. These reviews are conducted to ensure that the top
management is informed and involved in the quality-management system with respect to continuing adequacy and effectiveness,
and opportunities for improvement of the system. The management review is a process that should be conducted and audited utilizing
the process approach. A process approach is defined as “An activity using resources and managed in order to enable the transformation
of inputs into outputs” (ISO 9001:2000). All identified main processes in the quality system should be monitored through data
collection by appropriate methods, assuring that data are valid, representative, and adequate. For management review data
must be collected and presented in an accessible form so that processes can be evaluated according to objectives, goals, resources,
etc. On the basis of this information the laboratory management makes the necessary decisions and ensure that actions are
taken that improve the effectiveness of the quality-management system. As output from the management review process, there
should be evidence of decisions regarding: change of quality policy and objectives; plans and possible actions for improvements;
corrective actions as appropriate; increased customer satisfaction; and planning of resources needs. Identification of the
processes involved and using the process approach in the management review ensures the continual improvement of the quality
system.
Presented at the conference Quality in the Spotlight, March 2006, Antwerp, Belgium. 相似文献
87.
In this paper we evaluate the rotational viscosity and the two spin viscosities for liquid water using equilibrium molecular dynamics. Water is modeled via the flexible SPC/Fw model where the Coulomb interactions are calculated via the Wolf method which enables the long simulation times required. We find that the rotational viscosity is independent of the temperature in the range from 284 to 319 K. The two spin viscosities, on the other hand, decrease with increasing temperature and are found to be two orders of magnitude larger than that estimated by Bonthuis et al. [Phys. Rev. Lett. 103, 144503 (2009)] We apply the results from molecular dynamics simulations to the extended Navier-Stokes equations that include the coupling between intrinsic angular momentum and linear momentum. For a flow driven by an external field the coupling will reduce the flow rate significantly for nanoscale geometries. The coupling also enables conversion of rotational electrical energy into fluid linear momentum and we find that in order to obtain measurable flow rates the electrical field strength must be in the order of 0.1?MV?m(-1) and rotate with a frequency of more than 100 MHz. 相似文献
88.
Henrik Andersson Bertil Kågedal Carl-Fredrik Mandenius 《Analytical and bioanalytical chemistry》2010,398(3):1395-1402
Troponin T (TnT) is a useful biomarker for studying drug-induced toxicity effects on cardiac cells. We describe how a surface
plasmon resonance (SPR) biosensor was applied to monitor the release of TnT from active HL-1 cardiomyocytes in vitro when
exposed to cardiotoxic substances. Two monoclonal human TnT antibodies were compared in the SPR immunosensor to analyse the
TnT release. The detection limit of TnT was determined to be 30 ng/ml in a direct assay set-up and to be 10 ng/ml in a sandwich
assay format. Exposure of the cardiomyocytes to doxorubicin, troglitazone, quinidine and cobalt chloride for periods of 6
and 24 h gave significant SPR responses, whereas substances with low toxicity showed insignificant effects (ascorbic acid,
methotrexate). The SPR results were verified with a validated immunochemiluminescence method which showed a correlation of
r
2 = 0.790. 相似文献
89.
As wind turbines get larger, worries have emerged that the turbine noise would move down in frequency and that the low-frequency noise would cause annoyance for the neighbors. The noise emission from 48 wind turbines with nominal electric power up to 3.6 MW is analyzed and discussed. The relative amount of low-frequency noise is higher for large turbines (2.3-3.6 MW) than for small turbines (≤ 2 MW), and the difference is statistically significant. The difference can also be expressed as a downward shift of the spectrum of approximately one-third of an octave. A further shift of similar size is suggested for future turbines in the 10-MW range. Due to the air absorption, the higher low-frequency content becomes even more pronounced, when sound pressure levels in relevant neighbor distances are considered. Even when A-weighted levels are considered, a substantial part of the noise is at low frequencies, and for several of the investigated large turbines, the one-third-octave band with the highest level is at or below 250 Hz. It is thus beyond any doubt that the low-frequency part of the spectrum plays an important role in the noise at the neighbors. 相似文献
90.
Sigfridsson A Haraldsson H Ebbers T Knutsson H Sakuma H 《Magnetic resonance imaging》2011,29(2):202-208