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71.
Ralston J.D. Weisser S. Eisele K. Sah R.E. Larkins E.C. Rosenzweig J. Fleissner J. Bender K. 《Photonics Technology Letters, IEEE》1994,6(9):1076-1079
Modulation bandwidths of 24 GHz (Ibias=25 mA) and 33 GHz (Ibias=65 mA) are demonstrated for 3×100 μm2 In0.35Ga0.65As/GaAs multiple quantum well ridge-waveguide lasers with undoped and p-doped active regions, respectively. These performance enhancements have been achieved both by lowering the growth temperature of the high-Al-mole-fraction cladding layers and by utilizing short-cavity devices, fabricated with dry-etched facets using chemically-assisted ion-beam etching. Both the undoped and p-doped lasers also demonstrate modulation current efficiency factors exceeding 5 GHz/mA1/2, the best reported results for any semiconductor laser 相似文献
72.
The direct irradiation of the monomethoxybarrelene 8 gives cyclooctatetraene product 18 (Φ = 0.075) via the anti-Epiotis aromatic-vinyldiester [2π+2π] bridging route, and two semibullvalenes 16 (Φ = 0.075) and 17 (Φ = 0.075) from di-π-methane rearrangements initiating from vinyl-vinyldiester bridging. Benzophenone sensitization yields 16 (Φ =0.11) and 17 (Φ = 0.11). The dimethoxybarrelene 9 gives only semibullvalene 10 , this resulting from di-π-methane rearrangement involving the vinyl and vinyldiester bridges, upon direct (Φ = 0.009) or benzophenone sensitized irradiations (Φ = 0.38). 10 undergoes a vinylcyclopropane rearrangement to give semibullvalene 11 upon direct or acetone sensitized irradiations (Φ = 0.008). 相似文献
73.
With the help of an extended Cabibbo model for the weak hadronic vector current which includes the 10 and ¯10 representations to account for possibleΔS=-ΔQ transitions, a prediction is made for the quantity (1-¦x¦2)/¦1?x¦2 wherex=A(K0→πüe?¯v)/A(¯K0→πüe?¯v) using the experimental branching ratio Γ(K?→ π0e?¯v/Γ(K L 0 →πüe?¯v). From the known charge asymmetry in the decay of the long lived kaon one then obtains Re?. 相似文献
74.
The conduction properties of lecithin bilayer membranes in iodine-containing solutions are examined from a potentiodynamic experimental approach. Voltammetric data obtained by using a variety of forms (derived from charge-transfer type interactions) of iodide implicate the triiodide ion as the charge carrier accounting for the diffusion-limited voltammetric response whereas the charge transport of iodide seems to be limited by transmembrane diffusion. The data are used to support one of the many proposed mechanisms for conductance of iodide in membranes. 相似文献
75.
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77.
Reaction of benzyl-2,2-diphenyl-4-pentenylamine with a catalytic 1:2 mixture of [PtCl2(H2C=CH2)]2 (2.5 mol %) and PPh3 in dioxane at 120 degrees C for 16 h led to isolation of 1-benzyl-2-methyl-4,4-diphenylpyrrolidine in 75% yield. A number of gamma- and delta-amino olefins underwent intramolecular hydroamination to form the corresponding pyrrolidine derivatives in moderate to good yield. The reaction displayed excellent functional group compatibility and low moisture sensitivity. 相似文献
78.
T. Kaljuvee A. Trikkel R. Kuusik V. Bender 《Journal of Thermal Analysis and Calorimetry》2005,80(3):591-597
Summary The results of investigation of MgO participation in the binding of SO2 with lime-containing materials as sorbents are presented. Experiments of SO2 binding into solid phase using model samples of reactive grade MgO and CaO varying the mole ratio of MgO/CaO from 9:1 to 1:9 were carried out. Besides, dolomite and limestone samples with different MgO/CaO mole ratio (from 1.24 to 0.13) and samples of ashes formed at combustion of Estonian oil shale (containing 35-40% of carbonates) and its semicoke were studied Initial samples, intermediate and final products were subjected to chemical, IR-spectroscopy, X-ray and BET specific surface area analyses. The results of the present study confirmed the active participation of MgO in the binding of SO2 into the solid phase. In addition to CaSO4 the formation of Ca,Mg-double sulphate CaMg3(SO4)4 and -MgSO4 was observed. The presence of CaMg3(SO4)4 was fixed in a large temperature range 400-900°C and that of -MgSO4 in between 500-700°C. The optimum temperature range for formation and durability of CaMg3(SO4)4 was 700-800°C. 相似文献
79.
The determination of the concentration of hydrolytic enzyme solutions: alpha-chymotrypsin, trypsin, papain, elastase, subtilisin, and acetylcholinesterase 总被引:30,自引:0,他引:30
80.
A self-consistent calculation of thes- andp-wave resonance inπK-scattering is attempted using as input the exchanged resonances themselves and the exchange of a?-meson. While this approximation to the left-hand cut fails in thes-wave problem it produces ap-wave resonance but for a much too strong?-coupling. Position and width depend very sensitively on the inelastic region. Suppressing this region by a subtraction at threshold the subtraction constant can be adjusted to yield the observed position. The corresponding width is close to the experimental values for reasonable?-coupling. 相似文献