TEMPERATURE-AND TIME-RESOLVED SPECTROSCOPY OF CuUnS SEMICONDUCTOR NANOCRYSTALS WITH ZnS
نویسندگان
چکیده
THE SCIENCE OF VIRGINIA’S AQUACULTURE FEED PRICES. Brian L. Nerrie, Virginia Cooperative Extension, Virginia State University, Petersburg, VA 23806. Aquaculture feed costs are between 50-60% of the operating expenses. Aquaculture’s growth has resulted from improved knowledge of the nutritional requirements of aquacultured products. Initially nutrients were supplied by natural pond foods, and later by enhanced fertilization to improve pond productivity. Aquaculture feeds were developed that enabled farmers to provide uniform-size products to satisfy consumer demand for high quality affordable protein. Small changes in feed prices result in larger influences on product cost. Feed grains are a major component of aquaculture feeds. Increases in feed prices have resulted from alternative uses of acreage used for feed grain production especially biofuel development, decreased supply due to international demand for feed grains and local transportation costs. Economies of size in Virginia’s aquaculture industry add to prices.
منابع مشابه
Photothermal absorption spectroscopy of individual semiconductor nanocrystals.
Photothermal heterodyne detection is used to record the first room-temperature absorption spectra of single CdSe/ZnS semiconductor nanocrystals. These spectra are recorded in the high cw excitation regime, and the observed bands are assigned to transitions involving biexciton and trion states. Comparison with the single nanocrystals photoluminescence spectra leads to the measurement of spectral...
متن کاملSpectroscopy of neutral and charged exciton states in single CdSe/ZnS nanocrystals
We report a low temperature spectroscopic study of the lowest-energy exciton states in single CdSe/ZnS colloidal nanocrystals. In their neutral charge state, the zero-phonon lines of the lowest two levels of the band-edge exciton fine structure are directly observed in the photoluminescence spectrum. The attribution of these lines is confirmed by polarization-resolved studies of the photolumine...
متن کاملTHE INVESTIGATION ON SYNTHESIS AND OPTICAL PROPERTIES OF Ag-DOPED ZnS NANOCRYSTALS BY HYDROTHERMAL METHOD
Ag-doped ZnS nanocrystals were synthesized by hydrothermal method in propanetriol solutions. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) characterizations were used to determine the structure and morphology of ZnS: Ag nanocrystals. The as-prepared nanoparticles are approx...
متن کاملAbsorption cross-section spectrum of single CdSe/ZnS nanocrystals revealed through photoluminescence excitation spectroscopy
The absorption spectrum represents an important aspect of single semiconductor nanocrystals (NCs), revealing the morphology and orientation of the NCs. By conducting quantitative photoluminescence excitation spectroscopy based on a single-photon counting method, we succeed in clarifying the absorption cross-section spectrum of neutral excitons in single CdSe/ZnS NCs. With the values of the abso...
متن کاملThe synthesis and study of nanostructured materials have become a major interdisciplinary area of research over the past 20 ye
Pure and doped ZnS nanocrystalline phosphors were prepared at room temperature using a chemical synthesis method. Transmission electron microscopy observation shows that the size of the ZnS crystals is in the 2-3 nm range and SAED pattern confirms the cubic and crystalline nature of the observed samples, which are in agreement with X-Ray analysis. Interesting luminescence characteristics such a...
متن کامل