Results 1 - 10 of 68
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[en] Using the 1.31 × 10"1"0 J/ψ events and the data above open charm collected at BESIII detector, we studied and observed a lot of exotics, including X(3872), X(3823), Y(2175), Y(4140), Z_c(3900), Z_c(4020), and so on. Some of them are confirmed, some of them are observed for the first time, and some of them are searched, but with no obvious signal.
[en] Containment leak tightness and structural integrity test (hereinafter referred to as the containment test) is an important nuclear power plant comprehensive test, with participating departments, contractors, referred systematic, professional, long test time and so, you need to work closely with all parties to complete. Article describes the organization and preparation Fuqing Nuclear Units l and 2 during the commissioning containment test, test implementation and evaluation of test results, analysis and evaluation of the significance of the test, lack of Units l and 2 summarize the test, proposes follow-up unit recommendation for improvement. (authors)
[en] Electrolysis of solid chalcopyrite (CuFeS_2) against a graphite inert anode has been studied in equimolar NaCl-KCl melt at 700 °C. During electrolysis, S"2"− ions are released from the solid CuFeS_2 cathode, transfer to the graphite anode and discharge to S_2 gas. The reduction mechanism of CuFeS_2 was investigated by cyclic voltammetry, potentiostatic and constant voltage electrolysis together with spectroscopic and scanning electron microscopic analyses. The reduction contains mainly three stages: the insertion of Na"+ or K"+ into CuFeS_2, forming L_xCuFeS_2 (L = Na or K, x ≤ 1); the partial reduction of L_xCuFeS_2 to L_x_-_wCuFe_1_-_yS_2_-_z and Fe; the complete reduction to a mixture of Cu and Fe, which can be magnetically separated. After the separation, pure Cu can be obtained by leaching out the residual Fe with acid. Electrolysis at a cell voltage of 2.4 V has led to a rapid reduction of CuFeS_2. The current efficiency and energy consumption were 85% and 1.68 kWh/kg-CuFeS_2, respectively.
[en] Fe(x)/Mo(y) multilayered thin films (MLF) with y=7.0 nm and x=0.7, 1.3, 2.6, 3.6, 13.0 nm were fabricated by radio frequency (RF) sputtering. X-ray diffraction evidences that these films have a good periodicity and bcc structure for both Fe and Mo layers. Moessbauer spectra at room temperature (RT) are used to investigate the structure and the local magnetic properties of the interfaces between Fe and Mo layers. It is found that the interfaces present alloying features, i.e. the Fe atoms are randomly substituted by Mo atoms. Magnetic anisotropy which forces magnetic moments to lie in the film plane and reduced magnetic moments in interface region were observed. The specific magnetization of the films exhibits a BT3/2 dependence with very large values of B which can be attributed to the distribution of exchange interaction in the interfaces. (orig.)
[en] A method is introduced for the measurement of the integrated luminosity of the fast reconstructed data sample taken in BES II Ψ(3770) scan experiment. By using this method, the authors measured the integrated luminosity of the data sample taken at every energy points
[en] The band structure, density of states of AlxGa1−xN and InyGa1−yN was performed by the first-principles method within the local density approximation. The calculated energy gaps of the AlN, Al0.5Ga0.5N, GaN, In0.5Ga0.5N and InN were 5.48, 4.23, 3.137, 1.274 and 0.504 eV, which were in agreement with the experimental result. The dielectric functions, absorption coefficient and loss function were calculated based on Kramers–Kronig relations. Further more, the relationships between electronic structure and optical properties were investigated theoretically. For AlxGa1−xN and InyGa1−yN materials, the micromechanism of the optical properties were explained.
[en] The electron transfer within several dipeptides and their corresponding phosphorylated dipeptides was studied by electron pulse radiolysis, laser photolysis and electron spin resonance. The electron transfer rate constants were calculated by data modeling and kinetic analysis. It is found that the phosphoryl group in peptides participates the electron transfer process, and reduces the electron transfer rate in all cases. These are very important in life science since every biological process refers to the phosphorylation and nonphosphorylation of protein. It may be concerned in personalities and individualities of the personae. (author)
[en] Relativistic free-motion time-of-arrival theory for massive spin-1/2 particles is systematically developed. Contrary to the nonrelativistic time-of-arrival operator studied thoroughly in the previous literatures, the relativistic time-of-arrival operator possesses self-adjoint extensions because of the particle-antiparticle symmetry. The nonrelativistic limit of our theory is in agreement with the nonrelativistic time-of-arrival theory
[en] We report cascaded combiners for a high power continuous wave (CW) fiber laser in this paper. The cascaded combiners are fabricated with an improved lateral splicing process. During the fusing process, there is no stress or tension between the pump fiber and the double-cladding fiber. Thus, the parameters of the combiner are better than those that have been reported. The coupling efficiency is 98.5%, and the signal insertion loss is 1%. The coupling efficiency of the cascaded combiners is 97.5%. The pump lights are individually coupled into the double-cladding fiber via five combiners. The thermal effects cannot cause damage to the combiners and the cascaded combiners can operate stably in high power CW fiber lasers. We also develop a high power CW fiber laser that generates a maximum 780 W of CW signal power at 1080 nm with 71% optical-to-optical conversion efficiency. The fiber laser is pumped via five intra-cavity cascaded combiners and five extra-cavity cascaded combiners with a maximum pump power of 1096 W and a pump wavelength of 975 nm. (paper)
[en] Traditionally, the zitterbewegung (ZB) of the Dirac electron has just been studied at the level of quantum mechanics. Seeing the fact that an old interest in ZB has recently been rekindled by the investigations on spintronic, graphene, and superconducting systems, etc., this paper presents a quantum-field-theory investigation on ZB and obtains the conclusion that, the ZB of an electron arises from the influence of virtual electron-positron pairs (or vacuum fluctuations) on the electron. (atomic and molecular physics)