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81.
We show in this paper that little noise penalty is incurred by using readily available bipolar junction transistors in place of GaAs MESFETs in the first stage of high-speed optical transimpedance preamplifiers. 相似文献
82.
The temperature dependence of the rate of the reaction of OH with 2-(dimethylamino)-ethanol, (CH3)2NCH2CH2OH (DMAE) was investigated over the temperature range, 234 to 364 K. The reaction was studied using the flash photolysis-resonance fluorescence technique. The room temperature rate constant determined for this reaction was (10.3 ± 2.0) × 10?11 cm3 molecule?1 s?1, with essentially no temperature dependence evident within the uncertainty in the experiments. A value of (9.0 ± 2.0) × 10?11 cm3 molecule?1 s?1 is believed to best describe the reaction over the entire temperature range. The room temperature rate constant is about twice the value reported previously for this reaction. The overall reaction of OH with DMAE was apportioned to the reactivity of OH for abstracting individual H- atoms from different types of C? H bonds and the O? H bond within the molecule. This technique predicts the overall rate constant for the OH-DMAE reaction to within about 15% of the experimental value and makes it possible to estimate the yields of the initial radical products of the OH attack on DMAE. A mechanism is proposed for the subsequent atmospheric reactions that would occur in the photooxidation of DMAE. 相似文献
83.
84.
A relationship is derived between CN concentration and atomization efficiency in the C2H2-N2O flame. The relationship is examined under various experimental conditions and β values are estimated for a number of elements. The possibility of complex vapour phase oxide formation by U is considered. 相似文献
85.
Radio astronomical data available on the galactic background radiation has been carefully examined to deduce information on the existence or otherwise of a Galactic Radio Halo. It is shown that, though considerable doubt has been recently expressed by some regarding its existence, no convincing and quantitative reasoning has been so far advanced towards this; on the other hand, there are substantial arguments in its favour. 相似文献
86.
Summary We have calculated the energy spectrum of secondary protons produced in the atmosphere as a function of the atmospheric depth
and zenith angles at a location with zero geomagnetic cut-off. In this calculation, we have included all relevant energy losses
and production processes. It is shown that the protons produced from the target nuclei through recoil and evaporation processes
dominate the spectrum below 350 MeV. These calculations have been carried out over an energy region from 20 MeV to 40 GeV
and up to a depth of 40 g/cm2 of the atmosphere over a latitude with zero geomagnetic cut-off for both the periods of minimum and maximum solar modulation. 相似文献
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90.
R.J. Mcdonald A.J. Pacheco G.J. Wozniak H.H. Bolotin L.G. Moretto C. Schück S. Shih R.M. Diamond F.S. Stephens 《Nuclear Physics A》1982,373(1):54-80
Both the magnitude and alignment of the transferred angular momentum in the reaction 165Ho + 165Ho have been measured as a function of Q-value via continuum γ-ray multiplicity and anisotropy techniques. The spin transfer and the continuum γ-ray anisotropy increase throughout the quasi-elastic region. The spin transfer as a function of Q-value saturates at ~ 35?/fragment, the anisotropy peaks at a value of ~2 and then decreases to near unity for the largest Q-values. The observed anisotropies are in good agreement with predictions from an equilibrium statistical model in which thermal excitation of angular-momentum-bearing collective modes and neutron evaporation give rise to in-plane components of the angular momentum. 相似文献