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  • 1
    Electronic Resource
    Electronic Resource
    Tests of local transport theory and reduced wall impurity influx with highly radiative plasmas in the Tokamak Fusion Test Reactor (1999)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 877-884 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electron temperature (Te) profile in neutral beam-heated supershot plasmas (Te0∼6–7 keV ion temperature Ti0∼15–20 keV, beam power Pb∼16 MW) was remarkably invariant when radiative losses were increased significantly through gas puffing of krypton and xenon in the Tokamak Fusion Test Reactor [McGuire et al., Phys. Plasmas 2, 2176 (1995)]. Trace impurity concentrations (nz/ne∼10−3) generated almost flat and centrally peaked radiation profiles, respectively, and increased the radiative losses to 45%–90% of the input power (from the normal ∼25%). Energy confinement was not degraded at radiated power fractions up to 80%. A 20%–30% increase in Ti, in spite of an increase in ion–electron power loss, implies a factor of ∼3 drop in the local ion thermal diffusivity. These experiments form the basis for a nearly ideal test of transport theory, since the change in the beam heating power profile is modest, while the distribution of power flow between (1) radiation and (2) conduction plus convection changes radically and is locally measurable. The decrease in Te was significantly less than predicted by two transport models and may provide important tests of more complete transport models. At input power levels of 30 MW, the increased radiation eliminated the catastrophic carbon influx (carbon "bloom") and performance (energy confinement and neutron production) was improved significantly relative to that of matched shots without impurity gas puffing. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.873327
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  • 2
    Electronic Resource
    Electronic Resource
    Far infrared tangential interferometry/polarimetry on the National Spherical Tokamak Experiment : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 710-713 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Measurement of the core BT(r,t) value is essential in the National Spherical Tokamak Experiment (NSTX), since the effects of paramagnetism and diamagnetism in the NSTX are expected to be considerably greater than that in higher aspect ratio tokamaks. Therefore, without independent BT(r,t) measurement, plasma parameters dependent upon BT such as the q profile and local β value cannot be evaluated. Tangential interferometer/polarimeter systems (eight channels) [H. Park, L. Guttadora, C. Domier, W. R. Geck, and N. C. Luhman, Jr., First and Second NSTX Research Forums, Princeton, NJ, 1997 (unpublished)] for the NSTX will provide temporally and radially resolved toroidal field profile [BT(r,t)] and two-dimensional electron density profile [ne(r,t)] data. The outcome of the proposed system is extremely important to the study of confinement, heating, and stability of the NSTX plasmas. The research task is largely based on utilizing existing hardware from the TFTR multichannel infrared interferometer system [D. K. Mansfield, H. K. Park, L. C. Johnson, H. Anderson, S. Foote, B. Clifton, and C. H. Ma, Appl. Opt. 26, 4469 (1987) and H. K. Park, D. K. Mansfield, and C. L. Johnson, Proceedings of the 3rd International Symposium on Laser-Aided Plasma Diagnostic, Los Angeles, CA, 28–30 Oct. 1987 (unpublished), pp. 96–104] which will be reconfigured into a tangential system for NSTX, and to develop the additional hardware required to complete the system. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149364
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  • 3
    Electronic Resource
    Electronic Resource
    The artificial AT-rich block enhanced the production of bovine growth hormone in Escherichia coli (1999)
    Springer
    Bioprocess engineering 21 (1999), S. 293-298 
    Details
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In order to increase the synthesis of bovine growth hormone (bGH) using T7 promoter system in E. coli, the artificial AT-rich block was introduced into the upstream region of a consensus Shine-Dalgarno (SD) sequence and the spacer region (between SD and ATG codon) was enriched with A and T nucleotides. The cells harboring pTAJ plasmids with AT-rich block produced bGH in the range of 3% to 25% and the cells harboring pTBJ plasmids with AT-rich sequence in the spacer region from 0.8% to 20% of total cell proteins. This result suggests that AT rich block and AT nucleotides in the spacer region destabilize mRNA secondary structure, depending on the downstream coding information of bGH gene and also, implying that the disruption of mRNA secondary structure might be a major factor for regulating bGH expression in the translational initiation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009074
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  • 4
    Electronic Resource
    Electronic Resource
    Laser photochromic velocimetry estimation of the vorticity and pressure field – two-dimensional flow in a curved vessel (1999)
    Springer
    Experiments in fluids 26 (1999), S. 55-62 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Laser photochromic velocimetry was successfully used to determine details of a steady two-dimensional flow field. In the plane of symmetry of a 90° curved tube at a Reynolds number of 250, the axial and radial velocity fields were measured using laser photochromic velocimetry combined with a technique involving interpolation of the photochromic data. The wall shear stress, vorticity, and pressure field were also estimated. The experimental results were compared with those from numerical simulation. The agreement was remarkably good lending validity to the interpolation method used for this flow field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003480050264
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of intrapancreatic neuronal activation on cholecystokinin-induced exocrine secretion of isolated perfused rat pancreas (1999)
    Springer
    Pflügers Archiv 437 (1999), S. 511-516 
    Details
    ISSN: 1432-2013
    Keywords: Key words Cholecystokinin ; Cysteamine ; Intrapancreatic neuron ; Islets ; Pancreatic secretion ; Pertussis toxin ; Somatostatin ; Somatostatin antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The role of intrapancreatic neurons in the action of cholecystokinin (CCK) on pancreatic exocrine secretion of the totally isolated, perfused rat pancreas was investigated. Intrapancreatic neurons were activated by applying electrical field stimulation (EFS) to the isolated pancreas for 45 min. When applying EFS, spontaneous pancreatic secretions of fluid and amylase increased until the second 15-min period of EFS and then decreased during the third 15-min period. Atropine (2 µM) notably reduced the EFS-evoked pancreatic secretions of fluid and amylase. The CCK-induced (10 pM) pancreatic secretions of fluid and amylase elevated further in the first 15-min period of EFS and then gradually resumed to the levels observed during application of CCK alone in the third 15-min period of EFS. However, the CCK-induced pancreatic secretions remained elevated even in the third 15-min period of EFS when an action of endogenous somatostatin was inhibited by cyclo-(7-aminoheptanonyl-Phe-d-Trp-Lys-Thr[BZL]) (10 nM) or pertussis toxin (200 ng/ml). EFS further elevated spontaneous exocrine secretion by the cysteamine-treated (300 mg/kg) pancreas, but this was markedly reduced, to normal levels, by infusing somatostatin (100 pM). EFS increased the numbers of immunoreactive somatostatin cells in the Langerhans’ islets. The results indicate that intrapancreatic neuronal activation influences CCK-induced pancreatic secretions in a dual-phase pattern in the rat: an increase during the early phase and a decrease during the late phase. Endogenous somatostatin released from the islets appears to inhibit the enhancing effect of neuronal activation on CCK-induced pancreatic secretion. Of the intrapancreatic neurons, the cholinergic ones appear to predominate in EFS’s effects on CCK-induced pancreatic secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050811
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  • 6
    Electronic Resource
    Electronic Resource
    B-Spline Surface Approximation to Cross-Sections Using Distance Maps (1999)
    Springer
    The international journal of advanced manufacturing technology 15 (1999), S. 876-885 
    Details
    ISSN: 1433-3015
    Keywords: Keywords: B-spline; Cross-section; Distance map; Surface approximation; Surface skinning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001700050145
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  • 7
    Electronic Resource
    Electronic Resource
    Low Rank Approximation of a Hankel Matrix by Structured Total Least Norm (1999)
    Springer
    BIT 39 (1999), S. 757-779 
    Details
    ISSN: 1572-9125
    Keywords: Overdetermined linear systems ; rank reduction ; Hankel structure ; Toeplitz structure ; structured total least norm ; total least squares ; 1-norm ; 2-norm ; singular value decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The structure preserving rank reduction problem arises in many important applications. The singular value decomposition (SVD), while giving the closest low rank approximation to a given matrix in matrix L 2 norm and Frobenius norm, may not be appropriate for these applications since it does not preserve the given structure. We present a new method for structure preserving low rank approximation of a matrix, which is based on Structured Total Least Norm (STLN). The STLN is an efficient method for obtaining an approximate solution to an overdetermined linear system AX ≈ B, preserving the given linear structure in the perturbation [E F] such that (A + E)X = B + F. The approximate solution can be obtained to minimize the perturbation [E F] in the L p norm, where p = 1, 2, or ∞. An algorithm is described for Hankel structure preserving low rank approximation using STLN with L p norm. Computational results are presented, which show performances of the STLN based method for L 1 and L 2 norms for reduced rank approximation for Hankel matrices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022347425533
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  • 8
    Electronic Resource
    Electronic Resource
    Crystal Structure of A2+ (Mg1/3Nb2/3)O3, (A2+ = Sr2+ and Ca2+) Ceramics (1999)
    Springer
    Journal of materials science 18 (1999), S. 691-694 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006636026757
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of Hydrogenation and Thermal Annealing on the Electrical Properties of Au/p–ZnSe/n–GaAs Diodes (1999)
    Springer
    Journal of materials science 18 (1999), S. 467-469 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006642430837
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  • 10
    Electronic Resource
    Electronic Resource
    Mn K-Edge X-Ray Absorption Spectroscopic Study of Mn-Doped Zn2SiO4 Phosphors (1999)
    Springer
    Journal of materials science 18 (1999), S. 621-624 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006698918579
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