Different coastal sands of the city of El Jadida are used to filter wastewater from a cardboard manufacturing plant combined with fly ash and bottom ash （by-products of a local power plant）. The performances of five...Different coastal sands of the city of El Jadida are used to filter wastewater from a cardboard manufacturing plant combined with fly ash and bottom ash （by-products of a local power plant）. The performances of five matrices of these elements are compared in infiltration-percolation in vertical columns. The study of particle size sand is performed beforehand. The chemical and mineralogical composition of fly ash and bottom ash are produced by X-ray fluorescence and X-ray diffraction respectively. The wastewater samples were collected during a complete cycle of production of the cardboard. The heavy metals content before and after filtration was obtained by atomic emission spectrometry with inductively coupled plasma （ICP-AES）. The parameters analyzed were： total suspended solids （TSS）, organic matter COD, BODs, the potential hydrogen pH and heavy metals （iron, zinc and arsenic）. The results are very conclusive and respect the essence of control required by Moroccan regulations （law 1606-06） related to discharges from the papermaking and cardboard industry.展开更多
We study the oscillations in the spontaneous emission rate of an atom near a dielectric slab. The emission rate is calculated as a function of system size using quantum electrodynamics. It exhibits multi-periodic osci...We study the oscillations in the spontaneous emission rate of an atom near a dielectric slab. The emission rate is calculated as a function of system size using quantum electrodynamics. It exhibits multi-periodic oscillations. Four frequencies of the oscillations are extracted by Fourier transforms. They agree with actions of photon closed-orbits going away and returning to the atom. These oscillations are explained as manifestations of quantum interference effects between the emitted photon wave near the atom and the returning photon waves travelling along various closed-orbits.展开更多
We quantitatively study the Raman and photoluminescence （PL） emission from single-layer molybdenum disulfide （MoS2） on dielectric （SiO2, hexagonal boron nitride, mica and the polymeric dielectric Gel-Film） and c...We quantitatively study the Raman and photoluminescence （PL） emission from single-layer molybdenum disulfide （MoS2） on dielectric （SiO2, hexagonal boron nitride, mica and the polymeric dielectric Gel-Film） and conducting substrates （Au and few-layer graphene）. We find that the substrate can affect the Raman and PL emission in a twofold manner. First, the absorption and emission intensities are strongly modulated by the constructive/destructive interference within the different substrates. Second, the position of the Alg Raman mode peak and the spectral weight between neutral and charged excitons in the PL spectra are modified by the substrate. We attribute this effect to substrate-induced changes in the doping level and in the decay rates of the excitonic transitions. Our results provide a method to quantitatively study the Raman and PL emission from MoSa-based vertical heterostructures and represent the first step in ad hoc tuning the PL emission of 1L MoS2 by selecting the proper substrate.展开更多
文摘Different coastal sands of the city of El Jadida are used to filter wastewater from a cardboard manufacturing plant combined with fly ash and bottom ash （by-products of a local power plant）. The performances of five matrices of these elements are compared in infiltration-percolation in vertical columns. The study of particle size sand is performed beforehand. The chemical and mineralogical composition of fly ash and bottom ash are produced by X-ray fluorescence and X-ray diffraction respectively. The wastewater samples were collected during a complete cycle of production of the cardboard. The heavy metals content before and after filtration was obtained by atomic emission spectrometry with inductively coupled plasma （ICP-AES）. The parameters analyzed were： total suspended solids （TSS）, organic matter COD, BODs, the potential hydrogen pH and heavy metals （iron, zinc and arsenic）. The results are very conclusive and respect the essence of control required by Moroccan regulations （law 1606-06） related to discharges from the papermaking and cardboard industry.
基金The project supported by the Chinese National Key Basic Research Special Fund, the Natural Science Foundation of Beijing, and National Natural Science Foundation of China under Grant No. 90403028
文摘We study the oscillations in the spontaneous emission rate of an atom near a dielectric slab. The emission rate is calculated as a function of system size using quantum electrodynamics. It exhibits multi-periodic oscillations. Four frequencies of the oscillations are extracted by Fourier transforms. They agree with actions of photon closed-orbits going away and returning to the atom. These oscillations are explained as manifestations of quantum interference effects between the emitted photon wave near the atom and the returning photon waves travelling along various closed-orbits.
文摘We quantitatively study the Raman and photoluminescence （PL） emission from single-layer molybdenum disulfide （MoS2） on dielectric （SiO2, hexagonal boron nitride, mica and the polymeric dielectric Gel-Film） and conducting substrates （Au and few-layer graphene）. We find that the substrate can affect the Raman and PL emission in a twofold manner. First, the absorption and emission intensities are strongly modulated by the constructive/destructive interference within the different substrates. Second, the position of the Alg Raman mode peak and the spectral weight between neutral and charged excitons in the PL spectra are modified by the substrate. We attribute this effect to substrate-induced changes in the doping level and in the decay rates of the excitonic transitions. Our results provide a method to quantitatively study the Raman and PL emission from MoSa-based vertical heterostructures and represent the first step in ad hoc tuning the PL emission of 1L MoS2 by selecting the proper substrate.
