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61.
A unique method of coupling computational fluid dynamics (CFD) to model predictive control (MPC) for controlling melt temperature in plastic injection molding is presented. The methodology is based on using CFD to generate, via open-loop testing, a temperature and input dependent system model for multi-variable control of a three-heater barrel on an injection molding machine. Results clearly show the benefit of temperature and input dependent system models for MPC control, and that CFD can be used to dramatically reduce the time associated with open-loop testing through physical experiments. 相似文献
62.
W. Pfeiffer F. Sattler S. Vogler G. Gerber J.-Y. Grand R. Möller 《Applied physics. B, Lasers and optics》1997,64(2):265-268
Direct illumination of the tunneling gap in an ultrahigh vacuum scanning tunneling microscope with ultrashort pump-probe laser
pulses may offer ultimate spatial and temporal resolution in surface experiments. The electronic bandwidth of the tunneling
gap ( 1 THz) does not limit the time resolution. Our experiments show that multiphoton photoelectron emission from the sample limits
the application of this detection scheme at high laser fluence. However, a substrate specific pump-probe effect in the photoelectron
yield with femtosecond transients is observed on Tantalum and on GaAs(110) surfaces.
Received: 5 November 1996 相似文献
63.
T. Pfeifer D. Walter C. Winterfeldt C. Spielmann G. Gerber 《Applied physics. B, Lasers and optics》2005,80(3):277-280
We demonstrate the generation of arbitrarily shaped spectra of coherent soft X-ray radiation by adaptive control of the driving laser pulse. The selection of both narrow and wide spectral ranges as well as suppression of high-harmonic emission in a selected wavelength region is achieved. Feedback-controlled spectral engineering of coherent soft X-rays paves the way to shaping of soft X-ray pulses and coherent control of electron dynamics in the sub-femtosecond regime. 相似文献
64.
K. -H. Speidel L. Kleinen A. Gohla R. Ernst H. Busch G. Jakob U. Grabowy V. Roth J. Gerber 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(4):389-393
Measurements of transient magnetic fields (TF) were performed for the first time in the amorphous compounds of Fe80B20 and Fe85B15 for 24Mg(2+), 28Si(2+), 48Ti(2+) and 56Fe(2+) probe ions employing light and heavy ion beams. The motivation for these experiments was to investigate whether ion beam induced attenuations of TF are substantially weaker in these materials than in crystalline Fe. This expectation was indeed satisfied. The attenuations observed were found to be smaller at least by a factor of 2. 相似文献
65.
T. A. Bullions M. Wei F. E. Porbeni M. J. Gerber J. Peet M. Balik J. L. White A. E. Tonelli 《Journal of Polymer Science.Polymer Physics》2002,40(10):992-1012
Bulk poly(ethylene terephthalate) (PET) and bisphenol A polycarbonate (PC) samples have been produced by the coalescence of their segregated, extended chains from the narrow channels of the crystalline inclusion compounds (ICs) formed between the γ‐cyclodextrin (CD) host and PET and PC guests, which are reported for the first time. Differential scanning calorimetry, Fourier transform infrared, and X‐ray observations of PET and PC samples coalesced from their crystalline γ‐CD‐ICs suggest structures and morphologies that are different from those of samples obtained by ordinary solution and melt processing techniques. For example, as‐received PC is generally amorphous with a glass‐transition temperature (Tg) of about 150 °C; when cast from tetrahydrofuran solutions, PC is semicrystalline with a melting temperature (Tm) of about 230 °C; and after PC/γ‐CD‐IC is washed with hot water for the removal of the host γ‐CD and for the coalescence of the guest PC chains, it is semicrystalline but has an elevated Tm value of about 245 °C. PC crystals formed upon the coalescence of highly extended and segregated PC chains from the narrow channels in the γ‐CD host lattice are possibly more chain‐extended and certainly more stable than chain‐folded PC crystals grown from solution. Melting the PC crystals formed by coalescence from PC/γ‐CD‐IC produces a normal amorphous PC melt that, upon cooling, results in typical glassy PC. PET coalesced from its γ‐CD‐IC crystals, although also semicrystalline, displays a Tm value only marginally elevated from that of typical bulk or solution‐crystallized PET samples. However, after the melting of γ‐CD‐IC‐coalesced PET crystals, it is difficult to quench the resultant PET melt into the usual amorphous PET glass, characterized by a Tg value of about 80 °C. Instead, the coalesced PET melt rapidly recrystallizes during the attempted quench, and so upon reheating, it displays neither a Tg nor a crystallization exotherm but simply remelts at the as‐coalesced Tm. This behavior is unaffected by the coalesced PET sample being held above Tm for 2 h, indicating that the extended, unentangled nature of the chains in the noncrystalline regions of the coalesced PET are not easily converted into the completely disordered, randomly coiled, entangled melt. Apparently, the highly extended, unentangled characters of the PC and PET chains in their γ‐CD‐ICs are at least partially retained after they are coalesced. Initial differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared, and X‐ray observations are described here. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 992–1012, 2002 相似文献
66.
V. V. Glagolev R. M. Lebedev G. D. Pestova S. S. Shimansky M. Kravčíková M. Seman L. Šándor A. Dirner J. Hlaváčová G. Martinská J. Urbán K. U. Khairetdinov H. Braun J. P. Gerber P. Juillot A. Michalon A. K. Kacharava Z. P. Menteshashvili N. S. Nioradze Z. R. Salukvadze T. Sobczak J. Stepaniak 《Zeitschrift fur Physik C Particles and Fields》1993,60(3):421-425
4He-p collisions at two values of4He momenta 8.6 GeV/c and 13.6 GeV/c as well as the3He-p collisions at 13.5 GeV/c have been studies using the one-meter JINR hydrogen bubble chamber. Total, elastic, topological and reaction cross sections have been measured. The cross sections have been determined on a sample of minimum biased events. 相似文献
67.
M.B. Goldberg E. Konejung W. Knauer G.J. Kumbartzki P. Meyer K.-H. Speidel J. Gerber 《Physics letters. A》1976,58(4):269-271
PAC measurements on the 4.43 MeV 12C(2+) state on recoil in magnetized iron at velocities υion = 0.058c, 0.071c yield integral nuclear precession angles of Φ = ?0.18 (30), +0.17 (39) mrad respectively. Evidently, the high electron-spin-polarization transfer to the innermost carbon orbits implied by a previous measurement (υion = 0.03c, Φ = +0.85 (14) mrad) is suppressed at higher ion velocities. 相似文献
68.
69.
G. Hadjipanaysis S.C. Cornelison J.A. Gerber D.J. Sellmyer 《Journal of magnetism and magnetic materials》1980,21(1):101-107
We have studied the magnetic and electrical properties of several amorphous rare-earth—transition-metal alloys obtained by splat cooling. Low-field susceptibility, high-field magnetization and electrical resistivity measurements were made between 1.6 and 300 K. Mössbauer results are reported for (Gd65Fe35)90B10 at the temperatures of 80 and 300 K. Resistivity measurements show both positive and negative coefficients and in some cases maxima or minima that are associated with magnetic ordering or Kondo-type scattering, respectively. 相似文献
70.
Czechoslovak Journal of Physics - 相似文献