emit electrons when treated with heat in a process called thermionic emission. lanthanum boride crystals are used as electron emission sources for electron microscopes and ion thrusters used in spacecraft . the thermionic emission of electrons of lanthanum compounds is also exploited in carbon arc lamps...
& lighting we are able to supply different kinds of solar street lighting & lamps from china. ) free maintenance ; ) acid-lead battery ; ) special controller for solar lamp ; ) hours' working with full battery ; ) zinc-plated and plastic-coated steel frame with whole knit stainless steel fasteners....
ral heather violet ral claret violet ral blue lilac ral traffic purple ral purple violet ral signal violet ral pastel violet ral green blue ral ultramarine blue ral sapphire blue ral black blue ral brilliant blue ral azure blue ral gentian blue ral steel blue ral light blue ral cobalt blue ral pigeon...
ral heather violet ral claret violet ral blue lilac ral traffic purple ral purple violet ral signal violet ral pastel violet ral green blue ral ultramarine blue ral sapphire blue ral black blue ral brilliant blue ral azure blue ral gentian blue ral steel blue ral light blue ral cobalt blue ral pigeon...