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991.
Z P Li C S Tang J Y Su 《Science in China. Series B, Chemistry, life sciences & earth sciences》1991,34(5):599-605
Results from a systematic experiment on isolated perfused rat heart and isolated myocytes of adult rat showed that the mechanism of calcium influx during myocardial ischemia-reperfusion is due to the development of intracellular sodium overload during ischemic period; on reperfusion, the high intracellular Na+ content activated the reverse direction of Na(+)-Ca2+ exchange over myocardial sarcolemma (SL), thus a large quantity of extracellular Ca2+ fluxed over the SL to the intracellular space, forming a condition of intracellular Ca2+ overload, which leads to irreversible damage of the myocardium. 相似文献
992.
993.
Günter Georg Hoffmann Hans-Jürgen Hochkamp 《Fresenius' Journal of Analytical Chemistry》1992,344(4-5):227-228
Summary The application of a digital signal processor (DSP) to Fourier-transform infrared spectroscopy is described, which allows for near real-time display of the transformed interferograms as spectra. 相似文献
994.
Using a Bostick Gun as a plasma source, we have been investigating the effects of a moving plasma front on the frequency of an incident R.F. signal. We have been able to measure frequency shifts of 10 MHz frequency with a 2.6 GHz signal. The density is such that the plasma frequency is well above the transmitter frequency 1.3 meters from the plasma source. No magnetic field is used. 相似文献
995.
A. A. Vertiy S. P. Gavrilov S. G. Chumachenko 《International Journal of Infrared and Millimeter Waves》1991,12(4):367-375
Trancated equations have been obtained by the Green's functions method for a slowly varying amplitude of a transverse magnetic field component in a paramagnetic layer under conditions of the electron paramagnetic resonance (EPR). A magnetic susceptibiliti of the substence has been found from the Bloch equation for a homogeneously line breadth of the EPR. In a stationary case a solution of a nonlinear boundary-value problem is redused to a solution of two boundary problems for amplitude and phase equations. It is shown that unstable regimes of the electrodynamic system under inves tigation are possible.Electrodynamic characteristics of a nonlinear resonator of the Fabry-Pero type filled with a saturated paramagnetic medium have been analyzed numerically in a non-stationery case. 相似文献
996.
Transmission spectra of very thick TGS single crystals (e.g. thickness 8 mm) observed in the Far IR at 7 K do not need a high spectral resolution and nevertheless give evidence of Lorentz oscillators with damping coefficients as small as those considered for water vapour at a pressure of 0.2 atmospheres. 相似文献
997.
本文测定了几种二茂铁有机锡衍生物的119Sn,13C NMR谱。对其中几种衍生物的13C NMR谱进行了归属,从而进一步验证了这类化合物的结构。着重讨论了结构如化合物中取代基X的改变对119Sn化学位移的影响。并对结构如
类化合物N→Sn异侧配位的问题进行了讨论。 相似文献
998.
999.
本文阐述了伺服系统结构设计中估算系统固有频率的必要性,介绍了一种分析和计算经纬仪方位伺服系统扭转振动固有频率的方法。 相似文献
1000.
Ge segregation during the growth of Si1 − xGex alloys (x = 5, 10, 20, and 40%) was studied using X-ray photoelectron spectroscopy. The alloys were grown in thicknesses up to 20.0 nm at 500°C to measure quantitatively the amount of segregated surface Ge. The length of alloy needed to reach steady-state growth edge was found to decrease with increasing alloy concentration (4.8, 2.8, 2.4, and 2.0 nm, respectively). It was found that each alloy had a complete monolayer of Ge on the surface and an increasing amount of segregated Ge in the second layer (20, 55, 80, and 95%, respectively) during steady-state growth. An increase in the temperature of alloy growth (400–750°C) resulted in an increase in the leading edge of alloy growth but did not change the amount of segregated Ge during steady-state growth. We propose that film stress is responsible for the amount of Ge segregation. 相似文献