The palynology of the Plenmeller Coalfield and adjacent areas in Northern England

The samples collected in the present investigation from Featherstone, Plenmeller and adjacent areas in the North of England, yielded diverse, well preserved miospore assemblages with marked vertical variation, which compare fairly closely with those previously described from strata of the same age elsewhere. Six major Assemblages are recognised from coal and shale samples collected within Namurian and Westphalian A and B strata which have not previously been dated by miospore evidence. Oetailed comparisons are made with miospore assemblages previously described by several authors from similar stratigraphical horizons in Scotland, North England and. the Central Province. Formal taxonomic description is presented for 206 species belonging to 71 genera.tions 22 new types are described and one new combination is suggested.

Engineering surface states of carbon dots to achieve controllable luminescence for solid-luminescent composites and sensitive Be2+ detection

Luminescent carbon dots (L-CDs) with high quantum yield value (44.7%) and controllable emission wavelengths were prepared via a facile hydrothermal method. Importantly, the surface states of the materials could be engineered so that their photoluminescence was either excitation-dependent or distinctly independent. This was achieved by changing the density of amino-groups on the L-CD surface. The above materials were successfully used to prepare multicolor L-CDs/polymer composites, which exhibited blue, green, and even white luminescence. In addition, the excellent excitation-independent luminescence of L-CDs prepared at low temperature was tested for detecting various metal ions. As an example, the detection limit of toxic Be2+ ions, tested for the first time, was as low as μM.

Pabively Q-switched erbium-doped fiber laser using Fe3O4-nanoparticle saturable absorber

We experimentally demonstrate pabively Q-switched erbium-doped fiber laser (EDFL) operation using a saturable absorber (SA) based on Fe3O4 nanoparticles (FONPs). As a type of transition metal oxide, the FONPs have a large nonlinear optical response and fast response time. The FONPbased SA pobebes a modulation depth of 8.2% and nonsaturable absorption of 56.6%. Stable pabively Q-switched EDFL pulses with an output pulse energy of 23.76 nJ, a repetition rate of 33.3 kHz, and a pulse width of 3.2 μs were achieved when the input pump power was 110mW. The laser features a low threshold pump power of > 15mW.