Gas dynamic CO2-He-(N2) laser investigations

Experiments on IR laser action and gain measurements are reported for a CO2-containing gas mixture flow that cools as a result of expansion. The mixture is preheated by a reflected shock wave, and the gas is expanded into a vacuum through a slit. Laser action is obtained in a CO2-He mixture, while the addition of nitrogen increases the gain. The gain was found to depend on the distance from the slit and the gas pressure before the slit.     

Determination of likelihood of the development of pleural empyema in patients with cancer after pneumonectomy

Management of 150 patients with lung cancer after pneumonectomy has shown that the basic factors causing the onset of postoperative pleural empyema are chronic nonspecific pulmonary diseases, pronounced obstructive syndrome and right heart overload, tumor histology, local tumor size and cancer complications, duration and techniques of surgery, duration of controlled lung ventilation, as well as the onset of postoperative suppurative tracheobronchitis and surgical wound suppuration. The likelihood of empyema development may be assessed only upon analysis of the combination of risk factors with reference to their low informative value, preoperative patients' condition and intraoperative factors which have an equal impact on the onset of this complication. The efficacy of the algorithm elaborated is as follows: if the likelihood of empyema development exceeds 50%, it occurs in 96.3% of cases, if the likelihood of the complication is less than 10%, the postoperative period is uncomplicated in 87.8% of patients.     

Lateral transport and far-infrared radiation of electrons in In x Ga1 − x As/GaAs heterostructures with the double tunnel-coupled quantum wells in a high electric field

It is shown that the far-infrared radiation of electrons in the selectively doped heterostructures with double tunnel-coupled quantum wells in high lateral electric fields strongly depends on the level of doping of the wells. At a high impurity concentration in a narrow well, higher than (1−2) × 10¹¹ cm⁻², the radiation is caused only by indirect intrasubband electron transitions. At a lower concentration, along with the indirect transitions, the direct intersubband transitions also contribute to the radiation. These transitions become possible in high electric fields due to the real-space electron transfer between the quantum wells.