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We experimentally studied a passive mode-locked square-wave fiber laser with net-normal dispersion by using a nonlinear amplifying loop mirror. The output pulse width of the square-wave pulse (SWP) can be extended with the increasing of the pump power as well as single pulse energy. The SWP can be amplified without shape distortion when the mode-locked laser is injected into an erbium-ytterbium codoped fiber amplifier. Then, by inputting the amplified SWPs into a single mode fiber (SMF), a supercontinuum (SC) can be observed with the spectral range of about 1550 to 1850 nm. Broader and flatter SC with the 20-dB spectral range of about 1550 to 1950 nm can also be generated using a segment of dispersion-shifted fiber instead of SMF. [ABSTRACT FROM AUTHOR]

The crystal structure stability as well as electric conductance of (Sr/Ca)2CuO2Cl2compound with K2NiF4 structure was Investigated up to 31 GPa using diamond anvil technique. It seems that (Sr/Ca)2CuO2Cl2 is quite stable under pressure but with obvious anisotropic compressibility. The equation of state (EOS) obtained shows relative large bulk modulus. [ABSTRACT FROM AUTHOR]

One of the important problems of applied superconductivity is to understand, well describe and control the electromagnetic response due to flux motion. We show that the transport properties of type-II superconductors can be well described by a nonlinear response function. In connection with the superconducting-normal state (S-N) resistive transition we find further a model R(T, H) equation which fairly agrees with the experimental data of MgB[sub 2] as well as the untwined high critical temperature YBCO crystals. Instead of the constant R in the Ohm's law of normal metals, combining with Maxwell equations, this nonlinear resistance function over wide range of temperature, field and current provides a useful basis for engineering design and analysis. [ABSTRACT FROM AUTHOR]

Analyzes the properties of high-quality c-axis Nd[sub 1+x]Ba[sub 2-x]Cu[sub 3]O[sub 7-d] (Nd123) thin films produced by the laser ablation method. Resistivity of deposited films; Composition of the films under varied deposition conditions; Effect of laser fluence on the thin films.

Practical applications of the MgB2 prepared by the in situ method are usually limited because of the pores formed by the volatility of Mg. In order to improve the performance of MgB2 bulks, MgB2 bulks were fabricated through an in situ synthesis method with composites of B powder, Mg powder, and 10–100 wt% Mg(BH4)2 powder. The superconducting properties and grains structure of these MgB2 bulks were investigated, such as onset superconducting transition temperature (Tc), critical current density (Jc), porosity, resistivity (ρ), and grain connectivity. For the MgB2 bulk prepared from 80 wt% Mg(BH4)2 powder added composites, the Jc (1 T) value at 5 K was 4.1 × 105 A cm−2 and the onset Tc value was 37.5 K. Moreover, the microstructure of these MgB2 bulks was also analyzed using scanning electron microscope (SEM). The MgB2 bulk with less pores can be prepared with moderate Mg(BH4)2 powder added composite as precursor. The composites also provide raw materials for preparing high-quality in situ MgB2 superconducting wires. [ABSTRACT FROM AUTHOR]