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1.
Sub-critical crack growth rates of soda-lime-silicate glass and less brittle glass with different fictive temperatures were compared using the DCDC method under both dry and humid atmospheres in order to investigate the origin of the unique mechanical features of the less brittle glass developed by Ito and his collaborators. In both dry and humid atmospheres, the crack velocity of the soda-lime-silicate glass was slower than that of the less brittle glass. For both glasses, the glass sample with higher fictive temperature showed a slower crack growth rate under both dry and humid atmospheres. These observations can be explained by the tendency for the plastic flow at the crack tip; the soda-lime-silicate glass is expected to show easier plastic flow under tension than the less brittle glass, and also the samples with higher fictive temperatures are expected to show easier plastic flow, leading to greater fracture toughness, KIC, and slower crack growth rate. 相似文献
2.
We take the viewpoint that X(1576) is the tetraquark state which consists of a scalar diquark and an antiscalar-diquark in relative P-wave, and calculate its mass in the framework of the QCD sum rule approach. The numerical value of the mass mx= (1.66 =k 0.14) GeV is consistent with the experimental data. There might be some tetraquark components in the vector meson X(1576). 相似文献
3.
A. Bailini 《Applied Surface Science》2006,252(13):4364-4367
The effect of inert gas ionization on the dynamics of a laser ablation plume expanding through a background inert gas is studied. Charge transfer reactions between ablated ions and neutral background gas atoms yield to the formation of a charged layer on the plume expansion front. The energy lost by ablated ions when the plume is slowed down is calculated. The observed microstructure differences between carbon films prepared by pulsed laser deposition in helium, where the ionization mechanism is absent and respectively in argon, where it is present, are well correlated to model predictions. 相似文献
4.
5.
Ke-Ming Wang Bo-Rong Shi Xiang-Dong Liu Tian-Bing Xu Pei-Ran Zhu Jun-Si Zhu Qing-Tai Zhao 《Applied Physics A: Materials Science & Processing》1992,55(4):332-334
The effect of 2.0 MeV Cu+ irradiation on Si(100) crystal has been studied by the Rutherford backscattering/channeling technique. Analysis of the lattice disorder distribution has been performed under 100 direction of tilting off from the target normal: 7°, 30°, and 45° as well as different doses. The lattice disorder distributions in Si(100) have been compared with TRIM'89 simulation. The results show that the lattice disorder distributions in Si(100) under different irradiation angles seem to be in good agreement with TRIM'89 simulation. When the dose increases up to 8.7×1014 ions/cm2, the defect concentration increases leading to the formation of an amorphous layer. 相似文献
6.
The spin structure of protons will be discussed by using MIT-bag model and considering constituent quarks to be combined from current quarks and gluons. It will be shown that the gluonic degrees of freedom play an important role in prediction of the recent EMC results. 相似文献
7.
V.?Yu.?Grishina L.?A.?Kondratyuk W.?CassingEmail author M.?Mirazita P.?Rossi 《The European Physical Journal A - Hadrons and Nuclei》2005,25(1):141-150
Using the Quark-Gluon Strings Model --combined with Regge phenomenology-- we perform a comparative analysis of Λ, Σ0, Λ(1520) and Θ+ production in binary reactions induced by photon, pion and proton beams on the nucleon. We find that the existing experimental data on the γp↦K+Λ differential and total cross-sections can be described very well by the model for photon energies 1-16 GeV and - t < 2 GeV2 assuming a dominant contribution of the K* Regge trajectory. Moreover, using the same parameters we also reproduce the total γp↦K+Σ0 and γp↦K+Λ(1520) cross-sections suggesting a “universality” of the Regge model. In order to check the consistency of the approach we evaluate the differential and total cross-sections for the reaction π-p↦K0Λ which is also found to be dominated by the K* Regge trajectory. Using the apparent “universality” of the Regge model we extend our scheme to the analysis of the binary reactions γp↦¯0Θ+, π-p↦K-Θ+ and pp↦Σ+Θ+ as well as the exclusive and inclusive Θ+ production in the reactions pp↦p¯0Θ+ and pp↦Θ+X. Our detailed studies demonstrate that Θ+ production does not follow the “universality” principle, thus suggesting an essentially different internal structure of the exotic baryon relative to conventional hyperons or hyperon resonances. 相似文献
8.
W. Deconinck 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):653-655
An experimental search for the Θ(1540)- and Λ(1520)-resonance was performed in quasi-real photoproduction on deuterium at the HERMES experiment. While evidence for Θ(1540) was found in the decay channel pK
0
S→pπ
+
π
-, no evidence for the corresponding anti-particle was found. In some models it is expected that the Θ(1540) and the Λ(1520) have similar production mechanisms. The photoproduction cross-sections for the Λ(1520) in the decay channel Λ(1520)→pK
- and the corresponding anti-particle are determined. The partial photoproduction cross-sections for Λ(1520) and ˉ(1520) are obtained as σ
Λ(1520) = 65.3±8.8(stat)±6.9(syst)nb and σ
ˉ(1520) = 9.8±2.6(stat)±0.9(syst)nb, corresponding to a ratio R
Λ(1520) = σ
ˉ(1520)/σ
Λ(1520) = 0.15±0.05(stat)±0.02(syst). 相似文献
9.
A mixed-propagation picture for the expansion of an ablation plume through a buffer gas at different pressures is proposed after a brief discussion of the available analytical expansion models. Using parameter values deduced by the model the size of carbon clusters formed during plume propagation in helium is evaluated and compared with experimental data. Starting from experiments on silver plume propagation through molecular oxygen the size of silver clusters is predicted. 相似文献
10.
Semiconductor nanostructures with narrow band gap were synthesized by means of laser chemical vapor deposition (LCVD) of elements from iron carbonyl vapors [Fe(CO)5] under the action of Ar+ laser radiation (λL = 488 nm) on the Si substrate surface. The temperature dependence of the specific conductivity of these nanostructures in the form of thin films demonstrated typical semiconductor tendency and gave the possibility to calculate the band gap for intrinsic conductivity (Eg) and the band gap assigned for impurities (Ei), which were depended upon film thickness and applied electrical field. Analysis of deposited films with scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated their cluster structure with average size not more than 100 nm. Semiconductor properties of deposited nanostructures were stipulated with iron oxides in different oxidized phases according to X-ray photoelectron spectroscopy (XPS) analysis.These deposited nanostructures were irradiated with Q-switched YAG laser (λL = 1064 nm) at power density about 6 × 107 W/cm2. This irradiation resulted in the crystallization process of deposited films on the Si substrate surface. The crystallization process resulted in the synthesis of iron carbide-silicide (FeSi2−xCx) layer with semiconductor properties too. The width of the band gap Eg of the synthesized layer of iron carbide-silicide was less than for deposited films based on iron oxides Fe2O3−x (0 ≤ x ≤ 1). 相似文献