We systematically investigate the passive harmonic mode locking (HML) of the bound states of two solitons in a fiber laser that has been mode locked by nonlinear polarization rotation (NPR). The experiment shows that the stable HML state of the bound solitons (BSs) with a fixed and discrete separation is obtained. The repetition rate changes by increasing the pump power and slightly altering the polarization state in the cavity. The dynamic is similar to the HML of a single-pulse operation. In our experiment, the repetition rate can be turned from the fundamental mode locking up to ninth-order HML when the pump power is increased from 168 to 476.1 mW. Once the BSs are obtained, their separation is fixed at 1.5 ps, regardless of the HML order. Under the direct BS interaction, the BS trains are very stable and easily reproducible. This HML behavior of BSs confirms that the BS is another intrinsic feature of the laser, except for the single soliton.

Spectroscopic and Langmuir probe measurements are presented to characterize the argon glow discharge plasma generated by a cost-effective 50 Hz AC power source. Optical emission spectra (400-700 nm) are recorded for different gas flow rates and filling pressures at constant power level. The plasma parameters (electron temperature and density) are deduced from the relative intensities of Ar-I and Ar-II lines. The variation in the intensity ratio of the selected emission lines, electron temperature and density is studied as a function of gas flow rate and filling pressure. Slight increase in the intensity ratio I 2 (426.62 nm)/I 1 (404.44 nm) of the emission lines is observed whereas the electron temperature and density are found to decrease with increase in gas flow rate and filling pressure.

Nanostructured TiO2 films are deposited on a silicon substrate using 150-W power from the RF magnetron sputtering at working pressures of 3 to 5 Pa, with no substrate bias, and at 3 Pa with a substrate bias of −50 V. X-ray diffraction (XRD) analysis reveals that TiO2 films deposited on unbiased as well as biased substrates are all amorphous. Surface properties such as surface roughness and wettability of TiO2 films, grown in a plasma environment, under biased and unbiased substrate conditions are reported according to the said parameters of RF power and the working pressures. Primary rat osteoblasts (MC3T3-E1) cells have been cultured on nanostructured TiO2 films fabricated at different conditions of substrate bias and working pressures. The effects of roughness and hydrophilicity of nanostructured TiO2 films on cell density and cell spreading have been discussed.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-015-0732-7) contains supplementary material, which is available to authorized users.

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Drought stress negatively affects the cotton production all over the world. The negative impact of drought varies for different species due to some morphological and root attributes that help some species to better stand under drought. But the extent of disturbance varies for different cotton species. To find out such variation, two cotton species (Gossypium hirsutum and Gossypium arboreum) were studied under normal and drought conditions for 2 years. Two genotypes for each species were included, i.e. PC-1 and COMILLA (G. arboreum) and IUB-13 and IUB-65 (G. hirsutum). The experiment was laid out under a completely randomized design following factorial arrangement. Genotype × treatment × year interaction of cotton genotypes was studied for different root, morphological, physiological and fibre-related traits. Traits such as above ground dry biomass, above ground fresh biomass, chlorophyll contents, leaf area, seed cotton yield, sympodial branches/plant, fibre strength and ginning out-turn were higher in G. hirsutum genotypes as compared to G. arboreum genotypes. However less reduction under drought in all above mentioned traits was recorded for G. arboreum, than G. hirsutum. Furthermore, root traits; primary root length, lateral root numbers, root fresh weight and root dry weight were enriched under drought condition in G. arboreum genotypes than in G. hirsutum genotypes, which is a clear manifestation of higher drought tolerance ability in G. arboreum genotypes transferrable to G. hirsutum genotypes through interspecific crossing or other means.