Results of a steady TeV g-ray point-source search using data taken from the Tibet HD (1997 February -1999 September) and Tibet III (1999 November-2001 October) arrays are presented. From 0 to 60 in ...declination, significant excesses from the well-known steady source Crab Nebula and the high state of the flare-type source Markarian 421 are observed. Because the levels of significance from other positions are not sufficiently high, 90% confidence level upper limits on the flux are set assuming different power-law spectra. To allow cross-checking, two independently developed analyses are used in this work.
•Deviation from classic theory for laminar flow in rough tubes was confirmed.•Earlier transition between flow regimes was due to obstruction of roughness.•Range of transitional flow reduces with an ...increase in surface roughness.•Transitional flow disappeared in porous media with no limits between flow regimes.•Linear law for laminar flow in porous media may be an approximate expression.
This paper experimentally and theoretically investigated the differences on friction factor in rough pipes with large surface roughness. Deviation from theoretical theory for laminar flow in rough tubes was confirmed again. The product of fRe was larger than 64 and can be predicted as a quadratic equation of relative roughness. Earlier transition between flow regimes was observed. The critical Reynolds number between flow regimes decreased as the relative roughness increased. The range of Reynolds number for transitional flow regime gradually reduces with an increase in surface roughness. When relative roughness reach peak (Δ/d=1/2.4), transitional flow regime disappeared. Navier–Stokes equation was used to analyze the differences on flow behavior. It indicates flow obstruction of surface roughness caused curve flow for laminar flow in porous medium and linear law for laminar flow in porous media may be an approximate expression by neglecting the inertial forces at low Reynolds number.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Summary
Human leucocyte antigen (HLA) is a complex gene family that contains several highly polymorphic genes. Some studies have reported HLA‐A gene to have a strong role in idiopathic male ...infertility in Japanese and Yugoslavia populations. Prompted by these findings, we investigated the distributions of HLA‐A gene to ascertain their associations with idiopathic male infertility in Chinese population. Polymerase chain reaction–sequence‐based typing (PCR‐SBT) method was used for DNA typing at HLA‐A locus in 109 patients with idiopathic male infertility and 152 healthy controls in Han male population of Shaanxi Province, situated in north‐western China. In total, we detected 23 HLA‐A alleles in all infertile patients, 22 HLA‐A alleles in control subjects. However, no significant differences of these allelic frequencies were found between the patients and the control subjects, suggesting that the HLA‐A gene was unlikely a major risk factor of idiopathic male infertility in this sample population. As different populations have different HLA polymorphisms, investigation into the relationship of other HLA genes and idiopathic male infertility in our population is needed in the future.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Using 4.479×10^{8} ψ(3686) events collected with the BESIII detector, we search for the decays ψ(3686)→e^{+}e^{-}χ_{cJ} and χ_{cJ}→e^{+}e^{-}J/ψ, where J=0, 1, 2. The decays ψ(3686)→e^{+}e^{-}χ_{cJ} ...and χ_{cJ}→e^{+}e^{-}J/ψ are observed for the first time. The measured branching fractions are B(ψ(3686)→e^{+}e^{-}χ_{cJ})=(11.7±2.5±1.0)×10^{-4}, (8.6±0.3±0.6)×10^{-4}, (6.9±0.5±0.6)×10^{-4} for J=0, 1, 2, and B(χ_{cJ}→e^{+}e^{-}J/ψ)=(1.51±0.30±0.13)×10^{-4}, (3.73±0.09±0.25)×10^{-3}, (2.48±0.08±0.16)×10^{-3} for J=0, 1, 2, respectively. The ratios of the branching fractions B(ψ(3686)→e^{+}e^{-}χ_{cJ})/B(ψ(3686)→γχ_{cJ}) and B(χ_{cJ}→e^{+}e^{-}J/ψ)/B(χ_{cJ}→γJ/ψ) are also reported. Also, the α values of helicity angular distributions of the e^{+}e^{-} pair are determined for ψ(3686)→e^{+}e^{-}χ_{c1,2} and χ_{c1,2}→e^{+}e^{-}J/ψ.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Abstract Based on 4.5 fb −1 e + e − collision data collected with BESIII detector at seven energy points between 4.600 and 4.699 GeV, the branching fractions for Λ c + → pη $$ {\Lambda}_c^{+}\to ...p\eta $$ and Λ c + → pω $$ {\Lambda}_c^{+}\to p\omega $$ were measured by means of single-tag method. The branching fractions of Λ c + → pη $$ {\Lambda}_c^{+}\to p\eta $$ and Λ c + → pω $$ {\Lambda}_c^{+}\to p\omega $$ are determined to be (1.57 ± 0.11stat ± 0.04syst) × 10 −3 and (1.11 ± 0.20stat ± 0.07syst) × 10 −3, with a statistical significance of greater than 10σ and 5.7σ, respectively. These results are consistent with the previous measurements by BESIII, LHCb and Belle, and the result of Λ c + → pη $$ {\Lambda}_c^{+}\to p\eta $$ is the most precise to date.
In order to use a cheaper and homogeneous steel plate to replace the real stiffened panel in warhead tests, we numerically simulated and analyzed the deformation and failure characteristics of the ...stiffened panel as well as the force characteristics of the projectile in the warhead-target interaction. Based on the energy equivalence method, we first used the acceleration curve of the warhead in actual target penetration process as the reference for equivalent design and replaced it using a three-layered homogeneous steel plate. To visually assess their equivalence, we introduced Pearson correlation coefficient in statistical analysis to reflect their correlation. The results showed that the equivalent design method based on load characteristics make both consistent not only in the kinetic energy loss but also in the warhead's target-piercing acceleration process, thus realizing the equivalence from process to final state.
Synchrotron X-ray diffraction and transmission electron microscopy experiments are employed to investigate the mechanical stability of retained austenite in a quenching and partitioning steel. It is ...found that martensitic transformation takes place in high carbon blocky retained austenite at the onset of deformation, while low carbon film-like retained austenite, despite having a much lower carbon content, is stable at strains up to 12%. Two possible mechanisms are employed to explain these interesting findings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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