No abstract available

[en] The homoclinic bifurcation and chaos in a simple pendulum subject to bounded noise excitation is studied. The random Melnikov process is derived and the mean-square criterion is used to determine the threshold amplitude of the bounded noise excitation for the onset of the chaos in the system. The threshold amplitude is also determined by vanishing the numerically calculated largest Lyapunov exponent. It is found that the two values of the threshold amplitude are comparable over a large range of the intensity value of the random frequency. Finally, the Poincare maps are constructed to show the route from periodic motion to chaos or from random motion to random chaos as the amplitude of the bounded noise excitation increases and to further verify the two threshold amplitudes

[en] Optical detection is an important technique in studies and observations of air shower muons and relevant phenomena. The muon intensity is measured in a proper energy range and to study some problems about Cerenkov radiation of cosmic rays, by a muon telescope operated with Cerenkov detectors. It is found that the measured muon intensity agrees with the integral energy spectrum of cosmic ray muons

[en] In the present study, micromorphological and anatomic characteristics of 3 Pinus L. taxa (Pinus henryi, P. massoniana and P. tabulaeformis) were compared. These taxa have both endemic and limited distribution in China. For the micromorphological studies, the pollens were examined using light microscopy (LM) and scanning electron microscope (SEM). For the anatomical studies, needle anatomy characteristics of the 3 taxa were studied. After the studies, new characteristics of corpus exine ornamentation had been found. Spiny on the regulate of corpus exine is presented in P. henryi while baculate on the rugulate of corpus exine is existed in P. tabuliformishave. However, there is not ornamentation on rugulate in P. massoniana. The features of pollen size, corpus exine ornamentation, number of microperforations, cappula ridges are significant to distinguish the 3 taxa. Number of resin canals, stomatal rows, epithelial cells and sheath cells, dimensions of cross section, dimensions of resin canals and width of needle are also important in separating these taxa. These studies give taxonomic support for recognizing P. henryi as an independent species closely related to P. massoniana. (author)

[en] We propose a procedure to extract the probability for a valence particle being out of the binding potential from the measured nuclear asymptotic normalization coefficients. With this procedure, available data regarding the nuclear halo candidates are systematically analyzed and a number of halo nuclei are confirmed. Based on these results: we obtain a very relaxed condition for nuclear halo occurrence. Furthermore, we present the scaling laws for the dimensionless quantity < r²>/R² of the nuclear halo in terms of the analytical expressions of the expectation value for the operator r² in a finite square-well potential

[en] AC losses of NbTi-Cu and NbTi-Cu-CuNi superconducting composite magnets have been measured by means of an electronic integration technique. The experimental results are presented and their qualitative comparisons are made. It is shown within our experimental range that: (1) AC losses of NbTi-Cu composite magnet are proportional to the peak value and exciting velocity of the magnetic field; and (2) AC losses of NbTi-Cu-CuNi composite magnet are also proportional to the peak value of the magnetic field, but decrease as exciting velocity increases

[en] Complex fragments ranging in charge from 7≤Z≤45 have been detected in binary coincidence following the reaction of 8.4 MeV/u²³²Th+¹²C, and are shown to arise from the binary decay of a ²⁴⁴Cm compound nucleus. This work confirms earlier radiochemical observations of very light fragments in the fission fragment mass distribution, establishes their binary character, and interprets their yield in terms of finite range potential energy barriers. 15 refs., 3 figs

[en] Highlights: • MgB₂ thin film can be fabricated on single crystal Ag(1 1 1) face. • As the thickness of Ag layer increases, the T_c and J_c of MgB₂ decreases. When the Ag layer is 20 nm thick, the reduction of T_c is about 2 K. • Single crystal Ag layer is better than polycrystalline Ag layer in MgB₂ deposition. • May enable development of MgB₂ SNS junctions with single crystal Ag in the future. - Abstract: We have recently developed a method to deposit MgB₂ thin films on single crystal Ag layers, and found that thin Ag layers reduced the the superconductivity of MgB₂ not much, which may be a possible material to fabricate MgB₂ SNS Josephson junctions. The single crystal Ag layers were deposited on (0 0 0 1) SiC substrates, and then the MgB₂ thin films were deposited on the Ag layers. All the measurements included the XRD, M–T and M–H curves. The transition temperature of MgB₂ films decreases from 39 K to 37 K, while the thickness of Ag layers grows from 0 to 20 nm, and the critical current density at 4.2 K decreases from 1.76 MA/cm² to 1.24 MA/cm², too

[en] The effects of single and double masks on focused ion beam (FIB) direct patterning and chlorine-based inductively coupled plasma reactive ion etching (ICP-RIE) were studied in order to determine the influence of twice-deposited mask layers on the verticality of the side wall of silicon-based nanostructures. When a single mask was used as the etching mask, an inclined plane with a large side angle on the top area was formed. When a double mask was used, the first mask layer of chromium (Cr) was deposited by RF (radio frequency) magnetron sputtering and then directly patterned by FIB. Then, the secondary mask layer of SiO₂, which was deposited to protect the side wall in order to retard etching and prevent the formation of an inclined plane, was deposited by RF magnetron sputtering. However, the SiO₂ on the top and bottom of the nanostructure was removed through anisotropic etching by ICP-RIE, and only SiO₂ on the side wall was retained. The experimental results show that the SiO₂ layer left on the side wall as an etching barrier can effectively maintain the verticality of the nanostructure. The measurement results show that the verticality and aspect ratio of the nanostructure are 90.8° and 5.08 (depth: 310 nm, width: 61 nm), respectively. - Highlights: ► The effects of double masks on the verticality of the side wall were studied. ► The influences of the masks on reactive ion etching were realized. ► The secondary mask protects the silicon-based nano-structures.

[en] Angular distributions of elastic scatterings for ¹⁹F + ²⁰⁸Pb system have been measured at six energies around the Coulomb barrier. It is found that the real and imaginary potentials show pronounced energy dependence in terms of the phenomenological optical model analysis. The real parts of potentials extracted from the fusion data are similar to those from the elastic data. A comparison with the neighbouring systems of ¹⁶O + ²⁰⁸Pb and ¹⁶O + ²⁰⁹Bi reveals that the ¹⁹F deformations play an important role in the fusion reaction. Based on the deformed and energy dependent barrier penetration model, the calculated fusion cross sections and mean-square spin distribution agree with the experimental data well. Moreover, it is indicated that the enhancement of fusion cross sections attributes to the dynamic polarization effects around the barrier, and to the static deformation effects further below the barrier. (author)