Reliability Analysis of a Repairable C (2, 3; G ) System with Repair Priority and one is＂as good as new＂

In this paper, we discuss a repairable linear C (2, 3; G) system. One repairman carries out the maintenance of the system. It is assumed that the working time and the repair time of each component in the system are both exponentially distributed and only one component after repair is as good as new. Each component is classified as either a key component or an ordinary one according to its priority role to the system’s repair. We apply the geometric process, supplementary variable technique and generalized Markov process to study a repairable linear C (2, 3; G) system. We obtain Laplace transforms of some reliability indices such as availability and reliability.Key words: repairable system; generalized Markov process; key component; geometric proces

Ticking terahertz wave generation in attoseconds

We perform a joint measurement of terahertz waves and high-order harmonics generated from noble atoms driven by a fundamental laser pulse and its second harmonic. By correlating their dependence on the phase-delay of the two pulses, we determine the generation of THz waves in tens of attoseconds precision. Compared with simulations and models, we find that the laser-assisted soft-collision of the electron wave packet with the atomic core plays a key role. It is demonstrated that the rescattering process, being indispensable in HHG processes, dominant THz wave generation as well but in a more elaborate way. The new finding might be helpful for the full characterization of the rescattering dynamics.Comment: 4 figure

tert-Butyl 6-amino-3,4-dihydro-2H-1,4-benzoxazine-4-carboxyl­ate

The title mol­ecule, C13H18N2O3, contains a benzene ring fused to an oxazine ring and one tert-but­oxy­carbonyl group bound to the N atom of the oxazine ring. A weak intra­molecular C—H⋯O inter­action occurs. In the crystal, inter­molecular N—H⋯O and C—H⋯O hydrogen bonds stack the mol­ecules down the b axis. Weak C—H⋯N contacts connect the stacks, generating a three-dimensional network

Understanding the Passivation Mechanisms and Opto-Electronic Spectral Response in Methylammonium Lead Halide Perovskite Single Crystals

Attaining control over the surface traps in halide perovskites is critical for the tunability of ultimate device characteristics. Here, we present a study on the modulation of photophysical properties, surface traps, and recombination in MAPbI(3) single crystals (MSCs) with methylamine (MA) vapor surface treatment. Transient photoluminescence spectroscopy in conjunction with density functional theory calculations reveals that nonradiative recombination related to Pb2+ becomes mitigated after MA vaporing while radiative recombination via bimolecular path tends to increase, which originates from the passivation of Pb ions with the Lewis base nitrogen in MA. In contrast to the broad photoresponse in the pristine MSC photodiodes, application of MA surface treatments leads to a spectral narrowing effect (SNE) in MSCs with the response peak width</p