activated charcol phase loaded with 2-propylpiperidine-1-carbodithioate (ppcd) were synthesized based on chemical binding and physical adsorption approaches. the stability of a chemically modified ppcd especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of activated charcol immobilized ppcd. the application of this activ...

Single-walled carbon nanotube (SWNT) thin-film transistors hold great potential for flexible electronics. However, fabrication of air-stable n-type devices by methods compatible with standard photolithography on flexible substrates is challenging. Here, we demonstrated that by using a bilayer dielectric structure of MgO and atomic layer deposited (ALD) Al2O3 or HfO2, air-stable n-type devices c...

a new and simple method followed by atomic absorption spectrometry has been developedfor indirect determination of ascorbic acid (aa). the proposed method was based on the oxidationof aa to dehydroascorbic acid with cu2+cation(200mgl-1)in an ammonium thiocyanatesolution atph2.4. aa reduces cu2+to cu+followed by the precipitation of cu+ with scn-. then, the excess ofcu2+in the solution was measu...

some heavy metals are dangerous to health and there is rising concern about the quality of foodstuffs in some parts of the world. fish, particularly tuna fish, can concentrate huge quantities of several metals from water and they even play a significant role in human nourishment. objectives: in this study, the concentrations of mercury and four trace metals in five brands of canned tuna samples...

toxic heavy metals, such as lead (pb) and cadmium (cd) are widely used in industry and their accumulation in the living tissues may cause serious health problems and ecological hazards. twenty four moderately halophilic bacteria isolated from saline environments of iran were used to study their ability to bioremediation of lead and cadmium. amongst them, a gram-negative rod shaped bacterium, de...

The percentage composition of Al13, [AlO4Al12(OH)24(H2O)12]7+, in water treatment coagulants is an important criterion in the development and use of polymeric coagulants. Polymeric coagulants are generally used in cold climates or with highly turbid waters. Size exclusion chromatography flame atomic absorption spectrometry (SEC-FAAS) can separate Al13 and monomeric Al within 6 min. The percenta...

We demonstrate steady-state, mirrorless superradiance in a cold vapor pumped by weak optical fields. Beyond a critical pump intensity of 1 mW/cm2, the vapor spontaneously transforms into a spatially self-organized state: a density grating forms. Scattering of the pump beams off this grating generates a pair of new, intense optical fields that act back on the vapor to enhance the atomic organiza...

We present a laboratory demonstration of the Kramers-Kronig relation between the resonant absorption and refractive index in rubidium gas. Our experiment uses a rubidium vapor cell in one arm of a simple Mach-Zehnder interferometer. As the laser frequency is scanned over an atomic resonance, the interferometer output is affected by variations of both the absorption and refractive index of the g...