112 research outputs found
Creation of two-level liquid cooling system of PC
This paper devoted to creation of two-level liquid cooling system of PC. We found the solution to change a traditional air cooling system for the liquid cooling system with ethylene glycol as a coolant. The cooling system managed to reduce the temperature by up to 4-10°C while down time and ~11°C while load time
Resonance vector mode locking
A mode locked fibre laser as a source of ultra-stable pulse train has revolutionised a wide range of fundamental and applied research areas by offering high peak powers, high repetition rates, femtosecond range pulse widths and a narrow linewidth. However, further progress in linewidth narrowing seems to be limited by the complexity of the carrier-envelope phase control. Here for the first time we demonstrate experimentally and theoretically a new mechanism of resonance vector self-mode locking where tuning in-cavity birefringence leads to excitation of the longitudinal modes sidebands accompanied by the resonance phase locking of sidebands with the adjacent longitudinal modes. An additional resonance with acoustic phonons provides the repetition rate tunability and linewidth narrowing down to Hz range that drastically reduces the complexity of the carrier-envelope phase control and so will open the way to advance lasers in the context of applications in metrology, spectroscopy, microwave photonics, astronomy, and telecommunications
Structure-related bandgap of hybrid lead halide perovskites and close-packed APbX3 family of phases
Metal halide perovskites APbX3 (A+ = FA+ (formamidinium), MA+
(methylammonium) or Cs+, X- = I-, Br-) are considered as prominent innovative
components in nowadays perovskite solar cells. Crystallization of these
materials is often complicated by the formation of various phases with the same
stoichiometry but structural types deviating from perovskites such as
well-known the hexagonal delta FAPbI3 polytype. Such phases are rarely placed
in the focus of device engineering due to their unattractive optoelectronic
properties while they are, indeed, highly important because they influence on
the optoelectronic properties and efficiency of final devices. However, the
total number of such phases has not been yet discovered and the complete
configurational space of the polytypes and their band structures have not been
studied systematically. In this work, we predicted and described all possible
hexagonal polytypes of hybrid lead halides with the APbI3 composition using the
group theory approach, also we analyzed theoretically the relationship between
the configuration of close-packed layers in polytypes and their band gap using
DFT calculations. Two main factors affecting the bandgap were found including
the ratio of cubic (c) and hexagonal (h) close-packed layers and the thickness
of blocks of cubic layers in the structures. We also show that the dependence
of the band gap on the ratio of cubic (c) and hexagonal (h) layers in these
structures are non-linear. We believe that the presence of such polytypes in
the perovskite matrix might be a reason for a decrease in the charge carrier
mobility and therefore it would be an obstacle for efficient charge transport
causing negative consequences for the efficiency of solar cell devices
Qualimetric researches of educational resources: standardizing of light conditions in the light booth
Separation of variables for the quantum SL(2,R) spin chain
We construct representation of the Separated Variables (SoV) for the quantum
SL(2,R) Heisenberg closed spin chain and obtain the integral representation for
the eigenfunctions of the model. We calculate explicitly the Sklyanin measure
defining the scalar product in the SoV representation and demonstrate that the
language of Feynman diagrams is extremely useful in establishing various
properties of the model. The kernel of the unitary transformation to the SoV
representation is described by the same "pyramid diagram" as appeared before in
the SoV representation for the SL(2,C) spin magnet. We argue that this kernel
is given by the product of the Baxter Q-operators projected onto a special
reference state.Comment: 26 pages, Latex style, 9 figures. References corrected, minor
stylistic changes, version to be publishe
Genome Sequencing and Comparative Analysis of Saccharomyces cerevisiae Strains of the Peterhof Genetic Collection
The Peterhof genetic collection of Saccharomyces cerevisiae strains (PGC) is a large laboratory stock that has accumulated several thousands of strains for over than half a century. It originated independently of other common laboratory stocks from a distillery lineage (race XII). Several PGC strains have been extensively used in certain fields of yeast research but their genomes have not been thoroughly explored yet. Here we employed whole genome sequencing to characterize five selected PGC strains including one of the closest to the progenitor, 15V-P4, and several strains that have been used to study translation termination and prions in yeast (25-25-2V-P3982, 1B-D1606, 74-D694, and 6P-33G-D373). The genetic distance between the PGC progenitor and S288C is comparable to that between two geographically isolated populations. The PGC seems to be closer to two bakery strains than to S288C-related laboratory stocks or European wine strains. In genomes of the PGC strains, we found several loci which are absent from the S288C genome; 15V-P4 harbors a rare combination of the gene cluster characteristic for wine strains and the RTM1 cluster. We closely examined known and previously uncharacterized gene variants of particular strains and were able to establish the molecular basis for known phenotypes including phenylalanine auxotrophy, clumping behavior and galactose utilization. Finally, we made sequencing data and results of the analysis available for the yeast community. Our data widen the knowledge about genetic variation between Saccharomyces cerevisiae strains and can form the basis for planning future work in PGC-related strains and with PGC-derived alleles.PBD acknowledges the Russian Foundation for Basic Research (www.rfbr.ru) for grant 14-04-31265. OVT and SGIV acknowledge the Russian Foundation for Basic Research for grant 15-29-02526. JVS acknowledges the Russian Science Foundation (www.rscf.ru) for grant 14-50-00069 and the Saint-Petersburg State University for grant 1.38.426.2015. PBD, AGM, EAR, and JVS acknowledge the Saint-Petersburg State University for research grant 1.37.291.2015. PBD and OVT acknowledge the Saint-Petersburg City Committee on Science and High School (knvsh.gov.spb.ru/) for grants 15404 and 15919, respectively. PBD, AGM, JVS, and SGIV acknowledge the Saint-Petersburg State University for research grant 15.61.2218.2013. PBD acknowledges the Saint-Petersburg State University for research grant 1.42.1394.2015
Detection of Pionium with DIRAC
The aim of the DIRAC experiment at CERN is to provide an accurate determination of S-wave pion-pion scattering lengths from the measurement of the lifetime of the pi+ pi- atom. The measurement will be done with precision comparable to the level of accuracy of theoretical predictions, formulated in the context of Chiral Perturbation Theory. Therefore, the understanding of chiral symmetry breaking of QCD will be submitted to a stringent test
Climate variability during the past 2,000 years and past economic and irrigation activities in the Aral Sea basin
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594).
Conclusions:
GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
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