Mid-infrared w quantum-well lasers for noncryogenic continuous-wave operation

We review the recent progress of electrically injected and optically pumped mid-IR lasers based on antimonide quantum wells with the type II W configuration. W quantum-well diodes have achieved cw operation up to 195 K at lambda = 3.25 mum. Optically pumped devices that employ the diamond pressure bond heat sink have reached 290 K at 3 mum and 210 K at 6 mum. Pulsed power conversion efficiencies of up to 7% at 220 K have been attained by use of an optical pumping injection cavity approach, in which an etalon cavity for the pump beam significantly enhances its absorptance. The angled-grating distributed-feedback configuration has been used to obtain near-diffraction-limited output for an optical pumping stripe width of 50 mum.     

High-power (1W,CW) single-lobe operation of LPE-grown GaInAsP/GaInP ( lambda =0.8 mu m) separate-confinement single-quantum-well broad-area lasers

Liquid-phase epitaxy was used to grow single-quantum-well separate-confinement laser structures with a GaInAsP active layer. Broad-area devices with 100 mu m-wide stripes that were fabricated from these structures emit over 1 W of optical power per facet at a wavelength of 0.8 mu m in continuous room-temperature operation. A stable single-lobed far-field pattern with a beam divergence as low as 0.6 degrees is obtained in pulsed operation.<>     

Analysis of electromagnetic processes in the traction network under the interaction of electric locomotives in the regeneration and traction modes

An analysis of the results of simulation of electromagnetic processes in the “traction substation-catenary-electric locomotive” system with electric locomotives working in the feed zone in the traction and regenerative braking modes at different distances from the traction substation is carried out. A real-time computing complex was used for simulation. The mutual influence of electric locomotives and dispensing of active and reactive power was reviewed.     

The radiation therapy of skin cancer of the face

Results of three-year radiotherapy are assessed in 586 patients with skin cancer, with tumors localized on the skin of the face in 484 of these. The results of treatment were found to depend on the histological structure of the tumor and disease stage: 100% cure was attained in patients with basal-cell carcinomas and T1 stage, whereas only 7% of patients with T4 stage were cured; in patients with squamous-cell carcinoma these figures were, respectively, 96.2 and 10%.     

Changes in the sterol content of soybean oil after its thermal processing

A study was made of alterations in the composition of soybean oil sterols after thermal treatment. It was established that in heat-exposed oils, the content of total sterols dropped 20 to 50%. Analysis of a sample of free sterols from soybean oil heated for 13 h demonstrated a slight decrease in the content of stigmast-5-en-3 beta-ol at the expense of a rise in the concentration of delta 5-avenasterol, citrostadienol, and 24-methylene cycloartanol.     

Low-threshold, high-power, 1.3-μm wavelength, InGaAsP-InPetched-facet folded-cavity surface-emitting lasers

A 1.3-μm wavelength, InGaAsP-InP folded-cavity, surface-emitting laser with CH₄-H₂ reactive ion-etched vertical and 45° angled facets was demonstrated for the first time. Continuous-wave threshold currents of 32 mA have been achieved, with >15 mW CW power for the surface-emitted light. These surface-emitting lasers with two dry-etched facets are suitable for wafer-level testing and for monolithic integration with other InP-based photonic devices     

The use of cathodoluminescence for the development of durable self-glowing crystals based on solid solutions YPO<Subscript>4</Subscript>-EuPO<Subscript>4</Subscript>

Local cathodoluminescence spectroscopy has been suggested for the development of durable self-glowing crystals based on crystalline solid solutions (Y, Eu)PO₄. Nonradioactive ions of Eu³⁺ in these crystals cause strong luminescence in the visible range, initiated by small admixture (less than 1 wt %) of α-radioactive ²³⁸Pu. The intensity of self-glowing depends on the Y: Eu ratio and the ²³⁸Pu content. The optimal Y: Eu ratio responsible for the most intensive luminescence has been identified. The principal features of cathodoluminescence emission in (Y, Eu)PO₄ crystals of various chemical compositions are being discussed. The text was submitted by the authors in English.     

Study of the effect of rations containing dietary fiber on the level of total lipids and cholesterol in the blood and liver of the rat during a 6.5-month experiment

The influence of the following food fibers: wheat bran, citrus pectin, microcrystallized cellulose, methyl cellulose, was studied in experiments on male Wistar rats. Basing on the data obtained it has been suggested that the diets with pectin are conducive to secretion of general lipids and sterols from the liver. Comparison of the action of natural food fibers (wheat bran, pectin) with artificial fibers (microcrystallized cellulose, methyl cellulose) has not revealed any changes in the blood cholesterol level. At the same time a lower content of total lipids and cholesterol was recorded in the liver of rats that had received pectin and bran.