Hole distribution for (Sr,Ca,Y,La)_14 Cu_24 O_41 ladder compounds studied by x-ray absorption spectroscopy

The unoccupied electronic structure for the Sr_14Cu_24O_41 family of two-leg ladder compounds was investigated for different partial substitutions of Sr^2+ by Ca^2+, leaving the nominal hole count constant, and by Y^3+ or La^3+, reducing the nominal hole count from its full value of 6 per formula unit. Using polarization-dependent x-ray absorption spectroscopy on single crystals, hole states on both the chain and ladder sites could be studied. While for intermediate hole counts all holes reside on O sites of the chains, a partial hole occupation on the ladder sites in orbitals oriented along the legs is observed for the fully doped compound Sr_14Cu_24O_41. On substitution of Ca for Sr orbitals within the ladder planes but perpendicular to the legs receive some hole occupation as well.Comment: 10 pages RevTeX style with 7 embedded figures + 1 table; accepted by Phys. Rev.

Разработка системы автоматизации установки термической доподготовки тяжелой нефти

Объектом исследования является установка термической доподготовки нефти. Цель работы – разработка автоматизированной системы управления установки термической доподготовки нефти с использованием ПЛК, на основе выбранной SCADA-системы. В данном проекте была разработана система контроля и управления технологическим процессом на базе промышленных контроллеров ПЛК AllenBradley Micro 850, с применением SCADA-системы Master Scada Разработанная система может применяться в системах контроля, управления и сбора данных на различных промышленных предприятиях. Данная система позволит увеличить производительность, повысить точность и надежность измерений, сократить число аварий.The object of the study is the installation of thermal oil additional training. The work purpose – development of automated control system installation, additional training of thermal oil by using a PLC based on the selected SCADA-system. This project developed a system of monitoring and technological process control based on industrial PLC controllers Allen-Bradley Micro 850, with the use of SCADA Master Scada system Developed can be applied in systems monitoring, control and data acquisition in various industrial enterprises. This system will allow to increase productivity, to improve the accuracy and reliability of measurements to reduce the number of accidents

Self-energy of image states on copper surfaces

We report extensive calculations of the imaginary part of the electron self-energy in the vicinity of the (100) and (111) surfaces of Cu. The quasiparticle self-energy is computed by going beyond a free-electron description of the metal surface, either within the GW approximation of many-body theory or with inclusion, within the GW$\Gamma$ approximation, of short-range exchange-correlation effects. Calculations of the decay rate of the first three image states on Cu(100) and the first image state on Cu(111) are also reported, and the impact of both band structure and many-body effects on the electron relaxation process is discussed.Comment: 8 pages, 5 figures, to appear in Phys. Rev.