65 research outputs found
A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III
We established a method on measuring the \dzdzb mixing parameter for
BESIII experiment at the BEPCII collider. In this method, the doubly
tagged events, with one decays to
CP-eigenstates and the other decays semileptonically, are used to
reconstruct the signals. Since this analysis requires good separation,
a likelihood approach, which combines the , time of flight and the
electromagnetic shower detectors information, is used for particle
identification. We estimate the sensitivity of the measurement of to be
0.007 based on a fully simulated MC sample.Comment: 6 pages, 7 figure
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Joint analysis of three genome-wide association studies of esophageal squamous cell carcinoma in Chinese populations
We conducted a joint (pooled) analysis of three genome-wide association studies (GWAS) 1-3 of esophageal squamous cell carcinoma (ESCC) in ethnic Chinese (5,337 ESCC cases and 5,787 controls) with 9,654 ESCC cases and 10,058 controls for follow-up. In a logistic regression model adjusted for age, sex, study, and two eigenvectors, two new loci achieved genome-wide significance, marked by rs7447927 at 5q31.2 (per-allele odds ratio (OR) = 0.85, 95% CI 0.82-0.88; P=7.72x10ā20) and rs1642764 at 17p13.1 (per-allele OR= 0.88, 95% CI 0.85-0.91; P=3.10x10ā13). rs7447927 is a synonymous single nucleotide polymorphism (SNP) in TMEM173 and rs1642764 is an intronic SNP in ATP1B2, near TP53. Furthermore, a locus in the HLA class II region at 6p21.32 (rs35597309) achieved genome-wide significance in the two populations at highest risk for ESSC (OR=1.33, 95% CI 1.22-1.46; P=1.99x10ā10). Our joint analysis identified new ESCC susceptibility loci overall as well as a new locus unique to the ESCC high risk Taihang Mountain region
Numerical Investigation on the Thermal Performance of Nanofluid-Based Cooling System for Synchronous Generators
This paper presents a nanofluid-based cooling method for a brushless synchronous generator (BLSG) by using Al2O3 lubricating oil. In order to demonstrate the superiority of the nanofluid-based cooling method, analysis of the thermal performance and efficiency of the nanofluid-based cooling system (NBCS) for the BLSG is conducted along with the modeling and simulation cases arranged for NBCS. Compared with the results obtained under the base fluid cooling condition, results show that the nanofluid-based cooling method can reduce the steady-state temperature and power losses in BLSG and decrease the temperature settling time and changing ratio, which demonstrate that both steady-state and transient thermal performance of NBCS are improved as nanoparticle volume fraction (NVF) in nanofluid increases. Besides, although the input power of cycling pumps in NBCS has ~30% increase when the NVF is 10%, the efficiency of the NBCS has a slight increase because the 4.1% reduction in power loss of BLSG is bigger than the total incensement of input power of the cycling pumps. The results illustrate the superiority of the nanofluid-based cooling method, and it indicates that the proposed method has a broad application prospect in the field of thermal control of onboard synchronous generators with high power density
Study on Gradient-Dependent Nonlocal Damage Constitutive Models of Concrete under Freeze-Thaw Action
Cooling Ability/Capacity and Exergy Penalty Analysis of Each Heat Sink of Modern Supersonic Aircraft
The aerospace-based heat sink is defined as a substance used for dissipating heat generated by onboard heat loads. They are becoming increasingly scarce in the thermal management system (TMS) of advanced aircraft, especially for supersonic aircraft. In the modern aircraft there are many types of heat sinks whose cooling abilities and performance penalties are usually obviously different from each other. Besides, the cooling ability and performance penalty of a single heat sink is even different under different flight conditions—flight altitude, Mach number, etc. In this study, the typical heat sinks which are the fuel mass, ram air, engine fan air, skin heat exchanger, and expendable heat sink will be studied. Their cooling abilities/capacities, and exergy penalties under different flight conditions have been systematically estimated and compared with each other. The exergy penalty presented in this paper refers to the exergy loss of aircraft caused by the extra weight, drag and energy extraction of various heat sinks. The estimation models, as well as the results and discussion have been elaborated in this paper, which can be can be used to further optimize the TMS of modern advanced aircraft, for example, the layout design of various heat sinks and the improvement the control algorithm
Numerical Investigation on the Thermal Performance of Nanofluid-Based Cooling System for Synchronous Generators
Cooling Ability/Capacity and Exergy Penalty Analysis of Each Heat Sink of Modern Supersonic Aircraft
In Situ Observation on Dislocation-Controlled Sublimation of Mg Nanoparticles
Sublimation
is an important endothermic phase transition in which the atoms break
away from their neighbors in the crystal lattice and are removed into
the gas phase. Such debonding process may be significantly influenced
by dislocations, the crystal defect that changes the bonding environment
of local atoms. By performing systematic defects characterization
and in situ transmission electron microscopy (TEM) tests on a coreāshell
MgOāMg system, which enables us to āmodulateā
the internal dislocation density, we investigated the role of dislocations
on materialsā sublimation with particular focus on the sublimation
kinetics and mechanism. It was observed that the sublimation rate
increases significantly with dislocation density. As the density of
screw dislocations is high, the intersection of screw dislocation
spirals creates a large number of monatomic ledges, resulting in a
āliquid-likeā motion of solidāgas interface,
which significantly deviates from the theoretically predicted sublimation
plane. Our calculation based on density functional theory demonstrated
that the remarkable change of sublimation rate with dislocation density
is due to the dramatic reduction in binding energy of the monatomic
ledges. This study provides direct observation to improve our understanding
on this fundamental phase transition as well as to shed light on tuning
materialsā sublimation by āengineeringā dislocation
density in applications
In Situ Observation on Dislocation-Controlled Sublimation of Mg Nanoparticles
Sublimation
is an important endothermic phase transition in which the atoms break
away from their neighbors in the crystal lattice and are removed into
the gas phase. Such debonding process may be significantly influenced
by dislocations, the crystal defect that changes the bonding environment
of local atoms. By performing systematic defects characterization
and in situ transmission electron microscopy (TEM) tests on a coreāshell
MgOāMg system, which enables us to āmodulateā
the internal dislocation density, we investigated the role of dislocations
on materialsā sublimation with particular focus on the sublimation
kinetics and mechanism. It was observed that the sublimation rate
increases significantly with dislocation density. As the density of
screw dislocations is high, the intersection of screw dislocation
spirals creates a large number of monatomic ledges, resulting in a
āliquid-likeā motion of solidāgas interface,
which significantly deviates from the theoretically predicted sublimation
plane. Our calculation based on density functional theory demonstrated
that the remarkable change of sublimation rate with dislocation density
is due to the dramatic reduction in binding energy of the monatomic
ledges. This study provides direct observation to improve our understanding
on this fundamental phase transition as well as to shed light on tuning
materialsā sublimation by āengineeringā dislocation
density in applications
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