Terahertz radiation generation in multilayer quantum-cascade heterostructures

I–V and radiative characteristics of multilayer quantum-cascade GaAs/AlGaAs heterostructures with a double metal waveguide are investigated. The I–V characteristics typical of the quantum-cascade lasers are seen. The observed threshold-intensity growth and narrow radiation spectrum are characteristic of laser generation. The measured radiation frequency was found to be about 3 THz, which coincides with the calculated value. Thus, fully domestic terahertz quantum-cascade lasers are demonstrated for the first time.     

The Role of Excitation Photons Energy in the Photoinduced Carrier Dynamics in InGaAs/InAlAs Superlattice Heterostructures

Technical Physics Letters - The influence of excitation photons energy on the relaxation times of photoexcited carriers is studied. The involved relaxation mechanisms are evaluated and the...     

Study of electronic and magnetic properties of the CuFeS<Subscript>2</Subscript> semiconductor compound in the temperature range 77–300 K

The conductivity of polycrystalline chalcopyrite (CuFeS₂) samples is studied in the temperature range 77–300 K. Some differences in the low-temperature behavior of the conductivity in different samples are observed. The nuclear magnetic resonance spectrum of Cu in the local field in CuFeS₂ is studied in detail.     

Bearing capacity of cast-in-place piles on construction sites of the volgodonsk heavy machine-building plant

Conclusions 1. The behavior of large-diameter (a shaft diameter of 1 m, a pedestal diameter of 2.2 m, and a length of up to 25 m) cast-in-place piles subject to an increasing crushing load in a stratum of wetted loess soil is characterized, as with small-diameter piles, by a clear-cut transition from an elastic to a plastic state with small settlements (up to 12 mm).2. Pile settlement owing to compression of the shaft is a significant part (0.6) of the total settlement experienced by the pile within the loading range from 0 to P_ul.3. Computations of the bearing capacities of piles performed in accordance with an approximate solution of the problem of limiting equilibrium [4, 5] are in good agreement with data obtained from static pile tests in all cases under consideration; this made it possible to use them in designing the Nos. 1 and 3 frames of the plant with a savings of 1.5 million rubles.4. Computations of pile bearing capacities, which are performed in accordance with the plan outlined in Chapter II-17-76 of the Construction Norms and Specifications should be defined more precisely.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 13–16, March–April, 1977.