| 1. |
- Chu, M.S., et al.
(författare)
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Physics of Plasmas Modeling of Feedback and Rotation Stabilization of the Resistive Wall Mode in Tokamaks
- 2004
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Ingår i: Physics of Plasmas. ; 11, s. 2497-
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Tidskriftsartikel (refereegranskat)abstract
- Steady-state operation of the advanced tokamak reactor relies on maintaining plasma stability with respect to the resistive wall mode ~RWM!. Active magnetic feedback and plasma rotation are the two methods proposed and demonstrated for this purpose. A comprehensive modeling effort including both magnetic feedback and plasma rotation is needed for understanding the physical mechanisms of the stabilization and to project to future devices. For plasma with low rotation, a complete solution for the feedback issue is obtained by assuming the plasma obeys ideal magnetohydrodynamics ~MHDs! and utilizing a normal mode approach ~NMA! @M. S. Chu et al., Nucl. Fusion 43, 441 ~2003!#. It is found that poloidal sensors are more effective than radial sensors and coils inside of the vacuum vessel more effective than outside. For plasmas with non-negligible rotation, a comprehensive linear nonideal MHD code, the MARS-F has been found to be suitable. MARS-F @Y. Q. Liu et al., Phys. Plasmas 7, 3681 ~2000!# has been benchmarked in the ideal MHD limit against the NMA. The effect of rotation stabilization of the plasma depends on the plasma dissipation model. Broad qualitative features of the experiment are reproduced. Rotation reduces the feedback gain required for RWM stabilization. Reduction is significant when rotation is near the critical rotation speed needed for stabilization. The International Thermonuclear Experimental Reactor ~ITER! @R. Aymar et al., Plasma Phys. Controlled Fusion 44, 519 ~2002!# ~scenario IV for advanced tokamak operation! may be feedback stabilized with babove the no wall limit and up to an increment of ;50% towards the ideal limit. Rotation further improves the stability.
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| 2. |
- Adeyinka, A, et al.
(författare)
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Cytogenetic heterogeneity and clonal evolution in synchronous bilateral breast carcinomas and their lymph node metastases from a male patient without any detectable BRCA2 germline mutation
- 2000
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Ingår i: Cancer Genetics and Cytogenetics. - 0165-4608. ; 118:1, s. 42-47
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Tidskriftsartikel (refereegranskat)abstract
- Two synchronous bilateral breast carcinomas and their matched lymph node metastases from a 70-year-old man were cytogenetically analyzed. All four tumors were near-diploid, and except for the primary tumor from the right breast, had a 45,X,-Y clone in common. The loss of the Y chromosome was, however, common to all four tumors, whereas metaphase cells from peripheral blood lymphocytes showed a normal 46, XY chromosome complement. The primary tumor from the right breast was monoclonal, with loss of the Y chromosome and gain of 1q, whereas its metastasis had two related clones: the 45,X,-Y clone, and the other a more complex version of the clone in the primary tumor, with inv(3), -14, and del(16)(q13) as additional changes. The primary tumor from the left breast was polyclonal with three unrelated clones: 45,X,-Y/45,XY,-18/47,XY,+20, two of which were present in its metastasis. DNA flow cytometric studies showed diploidy for both primary tumors. No mutation in the BRCA2 gene was found on analysis of DNA from peripheral blood lymphocytes. The present findings show that del(16)(q13) is a recurrent finding among male breast carcinomas and that some of the primary cytogenetic abnormalities, as well as the pattern of chromosomal changes during the progression of sporadic breast carcinoma in the male, are similar to those in the female. In addition, the loss of the Y chromosome in the tumors but not in peripheral blood lymphocytes, suggests a possible role for this abnormality in the pathogenesis of male breast carcinoma.
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| 3. |
- Almqvist, Erik, et al.
(författare)
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Cardiac dysfunction in mild primary hyperparathyroidism assessed by radio-nuclide angiography and echocardiography before and after parathyroidectomy
- 2002
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Ingår i: Surgery. - : Elsevier BV. - 1532-7361 .- 0039-6060. ; 132:6, s. 1126-1132
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Tidskriftsartikel (refereegranskat)abstract
- Background.. Primary hyperparathyroidism (PHPT) is associated with increased cardiovascular morbidity for reasons that are incompletely understood. The present study was undertaken to evaluate the effects of parathyroidectomy on cardiac function especially in patients with mild PHPT Methods. Fifty patients with mild PHPT (serum calcium, 2.55 to 2.95 mmol/L) were randomized to parathyroidectomy either directly (group A) or after 1 year of observation (group B). Equilibrium radionuclide angiography (ERNA) at rest and at exercise was performed in addition to echocardiography on all patients at inclusion in the study and 1 and 2 years later. Results. Left ventricular mass index was larger (P <.05) in group B compared with group A after 2 years and showed significant correlation to the serum concentration of parathyroid hormone (but not Serum calcium) after 1 year. ERNA showed transient subclinical changes in both systolic and diastolic function Parameters after parathyroidectomy (decrease of left ventricular ejection fraction and peak fill-ingrate, with return to preoperative Levels within 1 year). Conclusions. Combined evaluation by ERNA and echocardiography has shown previously unknown aspects of parathyroid/myocardial interaction, which is consistent with an inotropic influence exerted by parathyroid hormone, and is in favor of early surgical treatment for PHPT irrespective of serum calcium levels.
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| 4. |
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| 6. |
- La Haye, R.J., et al.
(författare)
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Scaling of the Plasma Rotation Needed for Stabilizing the n = 1 Resistive Wall Mode (Ideal Kink) in the DIII D Tokamak
- 2004
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Ingår i: Nuclear Fusion. - 1741-4326 .- 0029-5515. ; 44, s. 1197-
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Tidskriftsartikel (refereegranskat)abstract
- Experiments in the DIII-D tokamak show that the n = 1 ideal kink can be stabilized by a resistive wall if the plasma is rotating fast enough. A database of the onset of the n = 1 resistive wall mode as a function of the equilibrium toroidal magnetic field, the plasma density and the toroidal rotation has been assembled for plasmas with beta between the theoretically predicted no wall and ideal wall stability limits. The critical rotation frequency is found to scale as the inverse of the Alfvén time with ? ?A 0.02 (evaluated at the q = 2 surface at ? 0.6) or ? ?S 0.7, where ?S is the sound time. The dependence of ? ? A or ? ?S on ?N/?N,no wall from 1?2 is weak and suggests the plasmas are in the 'intermediate dissipation' regime.
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| 7. |
- Bondeson, Lennart, et al.
(författare)
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Tumours of the thyroid and parathyroid
- 2004
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Ingår i: Pathology and Genetics of Tumours of Endocrine Organs (WHO Classification of Tumours; 8). - 9283224167 ; , s. 49-49
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
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| 9. |
- Jaun, André, et al.
(författare)
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Iterative solution of global electromagnetic wavefields with finite elements
- 2001
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Ingår i: Computer Physics Communications. - 0010-4655 .- 1879-2944. ; 135:1, s. 74-81
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Tidskriftsartikel (refereegranskat)abstract
- The time-independent Maxwell equations are solved iteratively in 2D geometry fur 3D global waves in plasma physics. Krylov space methods, such as the generalized- or the quasi-minimal residuals (GMRES or QMR), are applied together with an incomplete factorization (ILU) preconditioning to a formulation using nodal elements for the electromagnetic scalar and vector potentials. The plasma response is represented as a complex, frequency dependent, dielectric tensor operator and can be used for a variety of applications involving low frequency waves in a tokamak. The iterative approach does not only result in considerable memory savings, but it is also more efficient than a direct solution and paves the way for the parallelization of global wave and stability codes.
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| 10. |
- Liu, Yueqiang, 1971, et al.
(författare)
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Modeling of Resistive Wall Mode Experiments in JET
- 2004
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Ingår i: 30th EPS Conference on Plasma Physics and Controlled Fusion, June 28 - July 2, 2004, Imperial College, London, UK.. ; P1, s. 166-
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Konferensbidrag (refereegranskat)
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