Інтегральні генераторні модулі міліметрового діапазону

The designs of integrated generating modules of a millimeter range with summation of capacity of separate diodes and passive parametrical stabilization are submitted.Представлены конструкции интегральных генераторных модулей мм-диапазона с суммированием мощности отдельных диодов и пассивной параметрической стабилизацией.Представлені конструкції інтегральних генераторних модулів мм- діапазону з складанням потужностей окремих діодів та пасивною параметричною стабілізацією

Quantum chemical calculations of X-ray emission spectroscopy

The calculation of X-ray emission spectroscopy with equation of motion coupled cluster theory (EOM-CCSD), time dependent density functional theory (TDDFT) and resolution of the identity single excitation configuration interaction with second order perturbation theory (RI-CIS(D)) is studied. These methods can be applied to calculate X-ray emission transitions by using a reference determinant with a core-hole, and they provide a convenient approach to compute the X-ray emission spectroscopy of large systems since all of the required states can be obtained within a single calculation removing the need to perform a separate calculation for each state. For all of the methods, basis sets with the inclusion of additional basis functions to describe core orbitals are necessary, particularly when studying transitions involving the 1s or- bitals of heavier nuclei. EOM-CCSD predicts accurate transition energies when compared with experiment, however, its application to larger systems is restricted by its computational cost and difficulty in converging the CCSD equations for a core-hole reference determinant, which become increasing problematic as the size of the system studied increases. While RI-CIS(D) gives accurate transition energies for small molecules containing first row nuclei, its application to larger systems is limited by the CIS states providing a poor zeroth order reference for perturbation theory which leads to very large errors in the computed transition energies for some states. TDDFT with standard exchange-correlation functionals predicts transition energies that are much larger than experiment. Optimization of a hybrid and short-range cor- rected functional to predict the X-ray emission transitions results in much closer agreement with EOM-CCSD. The most accurate exchange-correlation functional identified is a modified B3LYP hybrid functional with 66% Hartree-Fock exchange, denoted B66LYP, which predicts X-ray emission spectra for a range of molecules including fluorobenzene, nitrobenzene, ace- tone, dimethyl sulfoxide and CF3Cl in good agreement with experiment

Efficiency of cluster generation in a magnetron discharge

The processes in the magnetron discharge involving metal atoms and metal clusters are analyzed. The efficiency of conversion of metal atoms in clusters is found in stationary magnetron discharge. The scheme of pulse magnetron discharge is considered with a variation of the buffer gas pressure after the electric pulse that provides an increase in the cluster generation efficiency in comparison with the stationary discharge

Processes of combustion of aluminium particles in gas discharge

The regime of combustion of aluminium microparticles involving oxidant molecules is analyzed if heating of these particles leads to evaporation of aluminium atoms from the particle surface which form aluminium nanoclusters and they, in turn, partake in chemical reactions. It is shown that the chemical process cannot provide the particle heating for this regime, and it results from particle heating by an external field of gas discharge

Angular and velocity distribution of nano-size cluster beams in a gas flow

The present work analyzes the cluster relaxation in the gas beam for clusters formed in a gas aggregation nanocluster sources in the framework of the small transition region model. The model applied provides plausible values for cluster velocities which are in a good agreement with measured ones and in the fair agreement with simulated by other researchers. The effect of separation of clusters of different masses in the beam due to dependence of their transversal velocity on the cluster mass is also studied

Clusters as a diagnostics tool for gas flows

The example of a gas flowing through an orifice into the surrounding rarefied space is used to demonstrate the possibility of using clusters for diagnosing gas flows. For the conditions studied (it takes a cluster velocity about the same time to relax to the gas velocity as it does to reach the orifice), information on the flow parameters inside the chamber is obtained from the measurement of the cluster drift velocity after the passage through an orifice for various gas consumptions. Other possible uses of clusters in gas flow diagnostics are discussed as well

Thermal fragmentation of nano-size clusters on surfaces

Nano-size silver clusters deposited on a silicon surface with a native-oxide layer undergo rapid thermal annealing, and after fast cooling a partial fragmentation into smaller clusters is observed. The observations are explained by a simple model where the behavior of a liquid droplet on a surface is characterized by the surface tension for a free droplet and the surface tension at the interface with the silicon surface. A method is suggested for the determination of the ratio of these parameters. Within the framework of this model cluster fragmentation into several smaller droplets is caused by thermal fluctuations due to droplet oscillations. The model could prove useful for controlling the size of nano-particles on a surface