804 research outputs found
Reconsideration of the QCD corrections to the decays into light hadrons using the principle of maximum conformality
In the paper, we analyze the decays into light hadrons at the
next-to-leading order QCD corrections by applying the principle of maximum
conformality (PMC). The relativistic correction at the -order level has been included in the discussion, which gives about
contribution to the ratio . The PMC, which satisfies the renormalization
group invariance, is designed to obtain a scale-fixed and scheme-independent
prediction at any fixed order. To avoid the confusion of treating -terms,
we transform the usual pQCD series into the one under the
minimal momentum space subtraction scheme. To compare with the prediction under
conventional scale setting, , after applying the PMC, we obtain
, where the
errors are squared averages of the ones caused by and . The PMC prediction agrees with the recent PDG value within errors, i.e.
. Thus we think the mismatching
of the prediction under conventional scale-setting with the data is due to
improper choice of scale, which however can be solved by using the PMC.Comment: 5 pages, 2 figure
RF-thermal-structural-RF coupled analysis on the travelling wave disk-loaded accelerating structure
Travelling wave (TW) disk-loaded accelerating structure is one of the key
components in normal conducting (NC) linear accelerators, and has been studied
for many years. In the design process, usually after the dimensions of each
cell and the two couplers are finalized, the structure is fabricated and tuned,
and then the whole structure characteristics can be measured by the vector
network analyzer. Before the structure fabrication, the whole structure
characteristics are less simulated limited by the available computer
capability. In this paper, we described the method to do the
RF-thermal-structural-RF coupled analysis on the TW disk-loaded structure with
one single PC. In order to validate our method, we first analyzed and compared
our RF simulation results on the 3m long BEPCII structure with the
corresponding experimental results, which shows very good consistency. Finally,
the RF-thermal-structure-RF coupled analysis results on the 1.35m long NSC KIPT
linac accelerating structure are presented.Comment: 5 pages, 16 figures, Submitted to the Chinese Physics C (Formerly
High Energy Physics and Nuclear Physics
Ultrafast all-optical switching via coherent modulation of metamaterial absorption
We report on the demonstration of a femtosecond all-optical modulator
providing, without nonlinearity and therefore at arbitrarily low intensity,
ultrafast light-by-light control. The device engages the coherent interaction
of optical waves on a metamaterial nanostructure only 30 nm thick to
efficiently control absorption of near-infrared (750-1040 nm) femtosecond
pulses, providing switching contrast ratios approaching 3:1 with a modulation
bandwidth in excess of 2 THz. The functional paradigm illustrated here opens
the path to a family of novel meta-devices for ultra-fast optical data
processing in coherent networks.Comment: 5 pages, 4 figure
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Circulating microRNAs: A Potential Role in Diagnosis and Prognosis of Acute Myocardial Infarction
Rapid and correct diagnosis of acute myocardial infarction (AMI) plays a crucial role in saving patients' life. Although some biomarkers (such as cardiac troponin and creatine kinase) are available for AMI diagnosis so far, there is still a clinical need for novel biomarkers, which can reliably rule in or rule out AMI immediately on admission. Circulating microRNAs (miRNAs) are a potential choice for novel biomarkers in AMI diagnosis and prognosis with high sensitivity and specificity. Circulating microRNAs are endogenous miRNAs that are detectable in whole blood, serum, or plasma in a highly stable form. Until now, around 20 circulating miRNAs were reported to be closely associated with AMI. In this minireview, we summarized recent available data on the correlation between circulating miRNAs and AMI. Some miRNAs, such as miR-208, miR-499, miR-133, and miR-1, were given special attention, since they may have a potential prospect in diagnosis and prognosis of AMI
A General Procedure for the Regioselective Synthesis of Aryl Thioethers and Aryl Selenides Through C–H Activation of Arenes
A general procedure for the synthesis of aryl thioethers and aryl selenides in one-pot through sequential iridium-catalyzed C–H borylation and copper-promoted C–S and C–Se bond formation is described. Functional groups including chloro, nitro, fluoro, trifluoromethyl, and nitrogen-containing heterocycles were all tolerated under the reaction conditions. Importantly, not only aryl thiols and selenides but also their alkyl analogs were suitable coupling partners, and the products were obtained in good yields with high meta regioselectivity
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