Photophysics of single silicon vacancy centers in diamond: implications for single photon emission

Single silicon vacancy (SiV) color centers in diamond have recently shown the ability for high brightness, narrow bandwidth, room temperature single photon emission. This work develops a model describing the three level population dynamics of single SiV centers in diamond nanocrystals on iridium surfaces including an intensity dependent de-shelving process. Furthermore, we investigate the brightness and photostability of single centers and find maximum single photon rates of 6.2 Mcps under continuous excitation. We investigate the collection efficiency of the fluorescence and estimate quantum efficiencies of the SiV centers.Comment: 15 pages, 7 figures, version 2 accepted for publication in Optics Expres

Micro-Raman Mapping of 3C-SiC Thin Films Grown by Solid–Gas Phase Epitaxy on Si (111)

A series of 3C-SiC films have been grown by a novel method of solid–gas phase epitaxy and studied by Raman scattering and scanning electron microscopy (SEM). It is shown that during the epitaxial growth in an atmosphere of CO, 3C-SiC films of high crystalline quality, with a thickness of 20 nm up to few hundreds nanometers can be formed on a (111) Si wafer, with a simultaneous growth of voids in the silicon substrate under the SiC film. The presence of these voids has been confirmed by SEM and micro-Raman line-mapping experiments. A significant enhancement of the Raman signal was observed in SiC films grown above the voids, and the mechanisms responsible for this enhancement are discussed

Human Cytomegalovirus IE1 Protein Elicits a Type II Interferon-Like Host Cell Response That Depends on Activated STAT1 but Not Interferon-γ

Human cytomegalovirus (hCMV) is a highly prevalent pathogen that, upon primary infection, establishes life-long persistence in all infected individuals. Acute hCMV infections cause a variety of diseases in humans with developmental or acquired immune deficits. In addition, persistent hCMV infection may contribute to various chronic disease conditions even in immunologically normal people. The pathogenesis of hCMV disease has been frequently linked to inflammatory host immune responses triggered by virus-infected cells. Moreover, hCMV infection activates numerous host genes many of which encode pro-inflammatory proteins. However, little is known about the relative contributions of individual viral gene products to these changes in cellular transcription. We systematically analyzed the effects of the hCMV 72-kDa immediate-early 1 (IE1) protein, a major transcriptional activator and antagonist of type I interferon (IFN) signaling, on the human transcriptome. Following expression under conditions closely mimicking the situation during productive infection, IE1 elicits a global type II IFN-like host cell response. This response is dominated by the selective up-regulation of immune stimulatory genes normally controlled by IFN-γ and includes the synthesis and secretion of pro-inflammatory chemokines. IE1-mediated induction of IFN-stimulated genes strictly depends on tyrosine-phosphorylated signal transducer and activator of transcription 1 (STAT1) and correlates with the nuclear accumulation and sequence-specific binding of STAT1 to IFN-γ-responsive promoters. However, neither synthesis nor secretion of IFN-γ or other IFNs seems to be required for the IE1-dependent effects on cellular gene expression. Our results demonstrate that a single hCMV protein can trigger a pro-inflammatory host transcriptional response via an unexpected STAT1-dependent but IFN-independent mechanism and identify IE1 as a candidate determinant of hCMV pathogenicity

СТЕНД-ИМИТАТОР ТУРБОВАЛЬНОГО ДВИГАТЕЛЯ АИ-450М ДЛЯ ИСПЫТАНИЙ РЕГУЛЯТОРА ДВИГАТЕЛЯ. МЕТРОЛОГИЧЕСКОЕ ОБЕСПЕЧЕНИЕ И АТТЕСТАЦИЯ СТЕНДА

The results of the development and state verification of the specialized test equipment for the engine digital regulator RDC-450M testing are given. This equipment is the test benchimitator which gives the possibility to calibrate and to test the regulator in laboratory by imitation of engine AI-450M as the system interacting with regulato. There is described the test bench structure and the information concerning the integrated in it mathematical model of engine AI-450M. The main test bench characteristics are given and the experience and the results of its state verification are elucidated. Приведены результаты работы по разработке и государственной аттестации специализированного испытательного оборудования для испытаний регулятора двигателя цифрового РДЦ-450М — стенда-имитатора, который, имитируя двигатель АИ-450М как взаимодействующую с регулятором систему, позволяет выполнять настройку, проверку и отладку регулятора в лабораторных условиях. Описана структура стенда, даны сведения об интегрированной в его состав математической модели турбовального двигателя АИ-450М. Приведены основные характеристики стенда-имитатора и освещены опыт и результаты проведения его государственной аттестации.

МЕТОДЫ И СРЕДСТВА МОДЕЛЬНОЙ ПОДДЕРЖКИ ПРОЦЕССОВ РАЗРАБОТКИ АСУ СТЕНДОВЫМИ ИСПЫТАНИЯМИ ГАЗОТУРБИННЫХ ДВИГАТЕЛЕЙ

The main requirements to ACS of technologic process of aviation engine stand test are shown. Problem questions, arising up at the informative and mathematical providing of ACS  development and exploitation are lighted up, and the ways of their decision are grounded. Solutions on architecture and composition of hardware and programmatic part of model support facilities intended for providing of development of indicated to ACS are resulted. The variants of raising the level of mathematical model adequacy and achievement of correspondence to the engine specific example are proposed. Future investigation prospects are determined. Отражены основные требования к АСУ технологическим процессом стендовых испытаний газотурбинных двигателей. Освещены проблемные вопросы, возникшие при информационном и математическом обеспечении процессов разработки и эксплуатации АСУ стендовыми испытаниями, и обоснованы пути их решения. Приведены предлагаемые решения по архитектуре и составу аппаратной и программной части средств модельной поддержки, предназначенных для обеспечения разработки указанных АСУ. Предложены варианты повышения адекватности математической модели и достижения соответствия конкретному экземпляру двигателя. Определены перспективы дальнейших исследований.