Dissipative Transitions between Bloch Bands

We study the effect of dissipative transport of two-band systems in a static electric field. With the help of numerical solutions of a stochastic Liouville equation for the density matrix, we find that the Markoffian dephasing will take electrons which are initially located in one band to equal population of the two bands, instead of undergoing Zener resonance, as they do in the absence of scattering.

Morphological and electrophysiological study on the inferior nodal extension and transitional cellular band in the rabbit atrioventricular junctional area

Background Advances in catheter ablation procedures for the treatment of supraventricular arrhythmias have created the need to understand better the morphological and electrophysiological characteristics of the inferior nodal extension (INE) and transitional cellular band (TCB) in the atrioventricular (AV) junctional area. Methods Firstly, we observed the histological features of 10 rabbit AV junctional areas by serial sections under light microscopy. Then we recorded the action potentials (APs) of transitional cells (TCs) in the INE, TCBs, AV node, and ordinary right atrial myocytes from the AV junctional area of 30 rabbits using standard intracellular microeletrode techniques. Results Under light microscopy, the INE appeared to be mostly composed of transitional cells linking upward to the AV node. Four smaller TCBs originated in the orifice of the coronary sinus, the region between the septal leaflet of the tricuspid valve and the coronary sinus, the inferior wall of the left atrium, and the superior interatrial septum, respectively, all linking to the INE or the AV node. Compared with ordinary atrial myocytes, the AP of the TCs in both the INE and the TCBs had a spontaneous phase 4 depolarization (not present in ordinary atrial myocytes), with a less negative maximum diastolic potential, a smaller amplitude, a slower maximum velocity of AP upstroke, and a longer action potential duration at 50% repolarization (APD 50) and at 30% repolarization (APD 30). The AP characteristics of these TCs were similar to those of the AV node, except that the velocities of the phase 4 spontaneous depolarization were slower and their action potential durations at 90% repolarization (APD 90) were shorter. Moreover, APD 50 and APD 30 of the TCs of the TCBs were shorter than in the case of TCs of the AV node. Conclusions The TCs of the INE and TCBs are similar to slow response automatic cells. They provide a substrate for slow pathway conduction. In addition, repolarization heterogeneity exists in the AV junctional area.

Synthesis and spectroscopic studies of Zn4B6O13 and Eu/Tb single-doped Zn4B6O13 phosphors

In this study, Zn4B6O13, Eu-and Tb-doped Zn4B6O13 phosphors were prepared by conventional solid state reaction method and the samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and photoluminescence spectroscopy（PL）. The doped rare-earth ions had little influence on the crystal structure of Zn4B6O13, but obviously affected the morphology of Zn4B6O13 particles. The PL results indicated that the 5% Eu-doped sample and 1% Tb-doped sample had the highest intensity in their respective different concentrations doped samples. The CIE chromaticity coordinates indicated that Zn4B6O13, Zn4B6O13：Eu and Zn4B6O13：Tb showed the three basic colors of blue, red and green, respectively. Evidently, the white light could appear only at appropriate intensity of blue, red and green components.