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排序方式: 共有746条查询结果,搜索用时 31 毫秒
91.
Kjellberg T. Hagberg M. Eriksson N. Larsson A.G. 《Photonics Technology Letters, IEEE》1993,5(10):1149-1152
The authors discuss the operation of InGaAs/AlGaAs grating-coupled surface-emitting lasers with threshold-current densities as low as 118 A/cm2, to the best of our knowledge the lowest reported for a surface emitter. The low threshold-current density is the result of high reflectivity and low absorption gratings in conjunction with a lateral effective refractive index step in the gain section. The gratings were fabricated using electron-beam lithography and chemically assisted ion-beam etching, producing uniform rectangular gratings. A thin etch-stop layer incorporated in the epitaxial structure made it possible to combine precise control of the grating position with a strained-layer SQW-GRINSCH structure for optimum low-threshold currents 相似文献
92.
E Hagstr?m-Toft J Bolinder S Eriksson P Arner 《Canadian Metallurgical Quarterly》1995,44(10):1170-1175
The effect of three types of phosphodiesterase (PDE) inhibitors on in vivo antilipolysis was investigated in healthy subjects using a 2-h euglycemic, hyperinsulinemic (40 mU.m-2.min) clamp together with microdialysis of abdominal subcutaneous adipose tissue. During hyperinsulinemia (approximately 330 pmol/l), the circulating glycerol concentration was reduced to approximately 50% of the basal level of 53.2 +/- 3.6 mumol/l, indicating an antilipolytic effect. The decrease in adipose tissue dialysate glycerol, which mirrors the change in interstitial glycerol concentration, was about 40% during hyperinsulinemia when Ringer's solution alone was perfused. Local perfusion with a selective PDE IV inhibitor, rolipram (10(-4) mol/l), did not influence the insulin-induced decrease in dialysate glycerol (F = 0.8 vs. perfusion with Ringer's solution by two-factor analysis of variance [ANOVA]), although rolipram increased the dialysate glycerol level by 144 +/- 7% of the baseline value. However, local perfusion with a selective PDE III inhibitor, amrinone (10(-3) mol/l), or a nonselective PDE inhibitor, theophylline (10(-2) mol/l), abolished the ability of insulin to lower dialysate glycerol (F = 16.5, P < 0.01 and F = 8.5, P < 0.01, respectively, as compared with perfusion with Ringer's solution). The findings could not be explained by changes in the local blood flow (as measured by a microdialysis--ethanol escape technique), which was not affected by hyperinsulinemia in the presence or the absence of PDE inhibitors in the dialysis solvent. We conclude that PDEs play an important role in mediating the antilipolytic effect of insulin in vivo and that PDE III is the dominant isoenzyme modulating this effect. 相似文献
93.
94.
All available thermodynamic and phase diagram data have been critically assessed for all phases in the CaO-Al2O3, Al2O3-SiO2, and CaO-Al2O3-SiO2 systems at 1 bar pressure from 298 K to above the liquidus temperatures. All reliable data for the binary systems have been
simultaneously optimized to obtain, for each system, one set of model equations for the Gibbs energy of the liquid slag and
all solid phases as functions of composition and temperature. The modified quasichemical model was used for the slag. With
these binary parameters and those from the optimization of the CaO-SiO2 system reported previously, the quasichemical model was used to predict the thermodynamic properties of the ternary slag.
Two additional small ternary parameters were required to reproduce the ternary phase diagram and ternary activity data to
within experimental error limits. The calculated optimized phase diagram and thermodynamic properties are self-consistent
and are the most reliable currently available estimates of the true values. 相似文献
95.
96.
A practical approach to detect and identify ceftazidime-hydrolyzing extended-spectrum mutants of OXA-10 beta-lactamase is presented. Large numbers of bacteria were screened by colony hybridization, a 720-bp part of blaOXA was amplified by PCR from the hybridization-positive isolates, and the products were digested by PvuII and HaeIII. 相似文献
97.
98.
A Eriksson J Ekholm B Hultén E Karlsson J Karlsson 《Canadian Metallurgical Quarterly》1976,7(1):159-165
1. (Methyl-3H)decamethonium dichloride was injected intravenously into the tail vein of dystrophic and normal mice of the Bar Harbour strain 129 ReJ/dy in paralysing doses. 2. Scintillation counts were made of 1 mm sections of diaphragm and tibialis anterior which showed a normal distribution of tritiated decamethonium in the dystrophic animals. 3. Intraperitoneal injections of L-(gamma-3H)leucine were made into dystrophic and normal mice. Examination of diaphragm and tibialis anterior by scintillation counting showed the abnormal uptake typical of dystrophic involvement of murine muscle. 4. The normal distribution of (methyl-3H)decamethonium dichloride uptake by the dystrophic muscle does not support the concept of active denervation in this disease. 相似文献
99.
Fuel-rich catalytic combustion of methane in zero emissions power generation processes 总被引:1,自引:0,他引:1
S. Eriksson M. Wolf A. Schneider J. Mantzaras F. Raimondi M. Boutonnet S. Jrs 《Catalysis Today》2006,117(4):447-453
A novel catalytic combustion concept for zero emissions power generation has been investigated. Catalysts consisting of Rh supported on ZrO2, Ce-ZrO2 or -Al2O3 were prepared and tested under fuel-rich conditions, i.e. for catalytic partial oxidation (CPO) of methane. The experiments were performed in a subscale gas-turbine reactor operating at 5 bar with exhaust gas-diluted feed mixtures.
The catalyst support material was found to influence the light-off temperature significantly, which increased in the following order Rh/Ce-ZrO2 < Rh/ZrO2 < Rh/-Al2O3. The Rh loading, however, only had a minor influence. The high activity of Rh/Ce-ZrO2 is probably related to the high dispersion of Rh on Ce-ZrO2 and the high oxygen mobility of this support compared to pure ZrO2. The formation of hydrogen was also found to increase over the catalyst containing ceria in the support material. 相似文献
100.
S. Eriksson 《Displays》1992,13(4):187-192
An experimental determination of perceptual thresholds for jitter in VDUs is reported. For jitter of a vertical line in a highly structured surround the jitter thresholds (jitter amplitude) varied between 5 and 10 seconds of arc depending on the frequency of the jitter. For jitter generated in a VDU designed for text presentation the displacement threshold of jitter (with a 10% criterion) was found to be 29 seconds of arc. 相似文献