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51.
The impedance rise that results from the accelerated aging of high-power lithium-ion cells containing LiNi0.8Co0.15Al0.05O2-based positive and graphite-based negative electrodes is dominated by contributions from the positive electrode. Data from various diagnostic experiments have indicated that a general degradation of the ionic pathway, apparently caused by surface film formation on the oxide particles, produces the positive electrode interface rise. One mechanistic hypothesis postulates that these surface films are components of the negative electrode solid electrolyte interphase (SEI) layer that migrate through the electrolyte and separator and subsequently coat the positive electrode. This hypothesis is examined in this article by subjecting cells with LiNi0.8Co0.15Al0.05O2-based positive and Li4/3Ti5/3O4-based negative electrodes to accelerated aging. The impedance rise in these cells was observed to be almost entirely from the positive electrode. Because reduction products are not expected on the 1.55 V Li4/3Ti5/3O4 electrode, the positive electrode impedance cannot be attributed to the migration of SEI-type fragments from the negative electrode. It follows then that the impedance rise results from mechanisms that are “intrinsic” to the positive electrode. 相似文献
52.
Ernest B. Cady Ann Lorek Yakito Takei John S. Wyatt Juliet M. Penrice A. David Edwards Donald Peebles Marzena Wylezinska Huw Owen-Reece Vincent Kirkbride Christopher E. Cooper Richard F. Aldridge Simon C. Roth Guy Brown David T. Delpy E. Osmund R. Reynolds 《Magma (New York, N.Y.)》1994,2(3):437-439
The aim of this study was to reproduce the delayed (secondary) cerebral energy failure previously described in birth-asphyxiated newborn infants and to investigate relationships between primary insult severity and the extent of the delayed energy failure. Phosphorus (31P) magnetic resonance spectroscopy (MRS) at 7 T was used to study the brains of 12 newborn piglets during an acute, reversible, cerebral hypoxic-ischemic episode which continued until nucleotide triphosphates (NTP) were depleted. After reperfusion and reoxygenation, spectroscopy was continued for 48 h. High-energy metabolite concentrations returned to near normal levels after the insult, but later they fell as delayed energy failure developed. The time integral of NTP depletion in the primary insult correlated strongly with the minimum [phosphocreatine (PCr)]/[inorganic orthophosphate (Pi)] observed 24–48 h after the insult. (Linear regression analysis gave slope –8.04 h–1; ordinate intercept=1.23;r=0.92;P<0.0001.) This model is currently being used to investigate the therapeutic potential of various cerebroprotective strategies including hypothermia. 相似文献
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54.
CF Chang LJ Kiser JE Bailey M Martins WC Gibson KA Schaberg DM Mirvis WB Applegate 《Canadian Metallurgical Quarterly》1998,279(11):864-869
In July 1996, Tennessee initiated a managed mental health and substance abuse program called TennCare Partners. This publicly funded "carve-out" experiment started chaotically and soon deteriorated into a crisis. Many patients did not receive care or lost continuity of care, and the traditional "safety net" mental health system nearly disintegrated. This qualitative case study sought to ascertain the impact of the TennCare Partners program. It points out that the program's difficulties stemmed directly from a flawed design that spread funds previously earmarked for severely mentally ill patients across the entire Medicaid population. States contemplating similar reforms should strive to protect vulnerable patients by risk-adjusting capitation payments and by focusing resources on care for severely mentally ill persons. States should also minimize program complexity and ensure the accountability of managed care networks for their patients' behavioral health care needs. 相似文献
55.
The technique of Fabry-Perot CCD annular-summing spectroscopy, with particular emphasis on applications in aeronomy, is discussed. Parameter choices for optimizing performance by the use of a standard format CCD array are detailed. Spectral calibration methods, techniques for determining the ring pattern center, and effects imposed by limited radial resolution caused by superpixel size, variable by on-chip binning, are demonstrated. The technique is carefully evaluated experimentally relative to the conventional scanning Fabry-Perot that uses a photomultiplier detector. We evaluate three extreme examples typical of aeronomical spectroscopy using calculated signal-to-noise ratios. Predicted sensitivity gains of 10-30 are typical. Of the cases considered, the largest savings in integration time are estimated for the day sky thermospheric O(1)D case, in which the bright sky background dominates the CCD read noise. For profile measurements of faint night sky emission lines, such as exospheric hydrogen Balmer-α, long integration times are required to achieve useful signal-to-noise ratios. In such cases, CCD read noise is largely overcome. Predictions of a factor of 10-15 savings in integration time for night sky Balmer-α observations are supported by field tests. Bright, isolated night sky lines such as thermospheric O(1)D require shorter integration times, and more modest gains dependent on signal level are predicted. For such cases it appears from estimate results that the Fabry-Perot CCD annular-summing technique with a conventional rectangular format may be outperformed by a factor of 2-5 by special CCD formats or by unusual optical coupling configurations that reduce the importance of read noise, based on the ideal transmission for any additional optics used in these configurations. 相似文献
56.
WANG Yong WANG Wei & LIU GuoPing Research Center of Information Control Dalian University of Technology Dalian China Faculty of Advanced Technology University of Glamorgan Pontypridd CF DL UK CTGT Center in Harbin Institute of Technology Harbin 《中国科学:信息科学(英文版)》2010,(6):1216-1223
This paper deals with the problem of exponential stability for a class of linear discrete switched systems with constant delays.The switched systems consist of stable and unstable subsystems.Based on the average dwell time method, some switching signals will be found to guarantee exponential stability of these systems.The explicit state decay estimation is also given in the form of the solutions of linear matrix inequalities(LMIs).An example relating to networked control systems(NCSs) illustrates the effect... 相似文献
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58.
It is not generally appreciated that pseudoxanthoma elasticum (PXE) can be associated with epidermal perforation by elastic fibers. We report an example of this phenomenon. The term "perforating PXE" is suggested and a distinction is made from elastosis perforans serpiginosa (EPS). We believe that most reported cases of coexistence of PXE and EPS are perforating PXE and that the coexistence of EPS has not been clearly demonstrated. 相似文献
59.
Emotional support is known to provide psychosocial benefits for women with breast cancer, but women can experience a mismatch between support that is wanted and support that is received from their personal supporter. The role of wanted and unwanted support in psychosocial adjustment was examined in 79 women recovering from breast cancer. Four distinct patterns of desired support actions were found using cluster analysis. Patterns of wanted support were not related to better or worse psychosocial adjustment. However, a misalignment of support between the provider and the receiver significantly influenced psychosocial adjustment, and unwanted but received support (support commission) was uniquely associated with poor psychosocial adjustment. Clinical interventions using the support instrument could help match support providers' actions to receivers' preferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
Miller Joshua D.; Reynolds Sarah K.; Pilkonis Paul A. 《Canadian Metallurgical Quarterly》2004,16(3):310
The authors examined the validity of D. R. Lynam and T. A. Widiger's (2001) prototypes for personality disorders (PDs) derived from the facets of the 5-factor model (FFM) of personality in 2 clinical samples. In the 1st sample (N = 94), there was good agreement between the prototypes generated by experts and the profiles reported by patients. These FFM PD similarity scores also demonstrated good convergent and discriminant validity with results from a semistructured interview and a self-report measure of Axis II pathology. In the 2nd sample (N = 132), the FFM PD similarity scores demonstrated excellent longitudinal stability and good predictive validity with regard to consensus ratings of PD features. The implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献