Guo Wentao

Identification of Oblate Band in Odd?Odd 184Au

High-spin states in 184Au have been populated via the 149Sm(29Si, 4n?) 184Au reaction at a beam energy of 140?MeV. Three- or higher-fold ?-ray coincidences have been measured using the multidetector array of GASP. A rotational band built on the 11? oblate ?h11/2?1??i13/2?1 structure has been newly observed, similar to those reported in 186?194Au. This result extends the knowledge of shape coexistence to the currently lightest odd?odd Au isotope.

Theoretical study on erbium ytterbium co-doped super-fluorescent fiber source

Erbium ytterbium co-doped super-fluorescent fiber source (EYD-SFS) has been simulated by a theoretical model based on rate equations and power transfer equations. The output performances of four basic structures of EYD-SFS have been expressed, and it indicated that the DPF structure is a preferable structure. The dependence of output power, mean wavelength and bandwidth stability on the pump fiber length and the concentration of Er3+ and Yb3+ have also been studied. The results indicated with a proper doping concentration of Er3+ and Yb3+ of 6.0 × 1026 ions/m3 and 1.0 × 1027 ions/m3, the optimal gain fiber length is 3.6 cm. In this condition, good performances of DPF structure of EYD-SFS have been achieved.

980 nm fiber grating external cavity semiconductor lasers with high side mode suppression ratio and high stable frequency

The coupling cavity theory is used to analyze the impact of high side mode suppression ratio (SMSR) on fiber grating external cavity semiconductor lasers (FGECSL). The high SMSR and high stable frequency FGECSLs were obtained by experiment. The center wavelength is 974 nm, SMSR is 45 dB, the center wavelength change rate reaches 3.08 ppm/?C in the temperature range of ?20 to 80 ?C.

Long-term storage life of light source modules by temperature cycling accelerated life test

Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope (IFOG). While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG.

Identification of a New Band and Its Signature Inversion in ^174Re

High spin states in 174Re are investigated via the 152Sm(27Al,5nγ)174Re reaction and γ−γ coincidence relationships are analysed carefully. A new band is identified due to its spectroscopic connection with the known π1/2−[541]⊗ν1/2−[521] band. This band is proposed to be the ground-state band built on the π1/2−[541]⊗ν5/2−[512] configuration in view of the low-lying intrinsic states in the neighbouring odd-mass nuclei. It is of particular interesting that the new band exhibits a phenomenon of low-spin signature inversion, providing a new situation for theoretical investigations.

Identification of New β-Delayed γ Rays and a Low-Spin Isomer in 176Ir

The ?+/EC decay of doubly odd nucleus 176Ir has been studied via the 146Nd(35Cl, 5n?) heavy ion fusion evaporation reaction at 210?MeV bombarding energy. With the aid of a helium-jet recoil fast tape transport system, the reaction products were transported to a low-background location for measurement. Based on the data analysis, the previously known ? rays from the decay of 176Ir are proven. Moreover, three new excited levels and ten new ? rays are assigned to 176Os. The time spectra of typical ? rays clearly indicate a long-lived low-spin isomer in 176Ir.

High-Spin States in Odd–Odd 140Pr Nucleus

High-spin level structure of doubly odd nucleus 140Pr has been investigated via the 130Te(14N,4n)140Pr reaction at beam energies from 55 to 65 MeV. Measurements of γ-ray excitation functions, γ-ray singles and γ-γ-t coincidences were performed with twelve BGO(AC)HPGe detectors. The level scheme of 140Pr, including 27 new levels and 42 new γ rays, has been established for the first time. The level structure is compared with those in the neighbouring odd–odd nuclei, and interpreted qualitatively.

Rapid evaluation method for the normal lifetime of an infrared light-emitting diode

Based on the Arrhenius model, a rapid evaluation method for an infrared diodes normal lifetime is proposed, and the theoretical model is constructed. Accelerated life testing of an infrared light-emitting diode (IRLED), which takes less time than usual, is carried out under temperature and electric current stress. Using this method, the activation energy and the IRLEDs normal lifetime are calculated and analyzed.