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71.
D. Charalambidis B. H. Feng C. Fotakis 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1989,14(3):223-227
Photoelectron angular distributions have been measured for the three-photon resonant one-photon ionization, (3+1), of Xe via the 7s[1 1/2]0 1 and 8s[1 1/2]0 1 states. The results are in good agreement with the theoretical predictions of Tang and Lambropoulos [13] for the 8s[1 1/2]0 1, but not for the 7s[1 1/2]0 1 state. Furthermore, the results are compared to those which have been obtained by Blazewicz et al. [1] for the three-photon resonant two-photon ionization, (3+2), of Xe via the 6s[1 1/2]0 1 state. 相似文献
72.
Limited land and insufficient technicians to operate a wastewater treatment system are main restrictions for many factories.
Therefore, an ideal wastewater treatment method for a small or land-limited factory must possess merits such as high performance
efficiency, high organic loading rate, little odor, simple operation, easy maintenance, and little land required (simultaneously).
An entrapment technique to immobilize mixed microorganisms to treat organic wastewater, which was developed in the present
work, possesses these characteristics. This project was done on a laboratory scale. The microorganisms were activated sludge
(an undefined mixture of microorganisms obtained directly from a domestic wastewater treatment plan) and the mixed microorganisms
were immobilized in cellulose triacetate by means of an entrapment technique to treat organic wastewater from food industry.
After wastewater was treated by this system, the SCOD (soluble COD) removal efficiency of 81% evaluated samples exceeded 80%
in 1.5 ± 0.9 g SCOD/L/d of the volumetric loading rate and 7–10 h for the hydraulic retention time. This wastewater treatment
method can be applied to other organic industrial wastewater. 相似文献
73.
The reaction kinetics between O2? and C6H5CH2Br has been investigated in N,N′-dimethylformamide by electroanalytical techniques. A mechanism is proposed in which two molecules of the primary electrode product regenerate, via a following chemical reaction, one molecule of the original electroactive species. Furthermore, evidence for a SN2 reaction mechanism between O2? and C6H5CH2Br has been obtained. Second order rate constants resulted to be 11000 M?1s?1 and 3000 M?1s?1at room temperature and 0°C, respectively. The main products of the reaction were found to be benzylalcohol, benzaldehyde, benzene and biphenyl. 相似文献
74.
Thermodynamics and crystallization kinetics of the hydrothermal synthesis of Na4Ti4Si3O10 (NaTS) were systemically studied by both experiments and model simulation. Experimental results showed that the curve of
crystallinity with time was a characteristic signmoid in the shape that indicated the crystallization of Na4Ti4Si3O10 was a typical spontaneous nucleation process on the laboratory scale. Crystallization of NaTS belongs to the liquid-liquid
transformation mechanism and the reaction is endothermic (ΔH = 15.3 kJ/mol). A mathematic model of crystallization kinetics was developed to simulate the synthesis of NaTS. Runge-Kutta
and simplex methods were adopted to solve the partial differential equations. Model results fitted well with the experimental
data and showed that the synthesis process belongs to spontaneous nucleation and crystal growth. Moreover, the very small
crystal growth constant (5.6·10−7) and gel dissolution constant (7.0·10−7) indicate they are the rate-limiting steps of the whole synthesis process. 相似文献
75.
Lili Hu Marcus Wolf Michael Grätzel Zhonghong Jiang 《Journal of Sol-Gel Science and Technology》1995,5(3):219-226
The hydrolysis of niobium pentaethoxide precursor in the presence of triethylamine (TEA) is discussed. Three precursors with TEA/Nb(OEt)5 mole ratios of 0.25, 0.4 and 0.8 were prepared. Niobia colloids with different appearance were obtained after autoclaving the above precursors at 250°C during 12 h. The surface roughness and microstructure of niobia films prepared with the colloids by spread coating method are strongly dependent on the TEA/Nb(OEt)5 mole ratio. At a value of 0.4 TEA/Nb(OEt)5 mole ratio, a niobia film with large surface roughness can be achieved. It is opaque and mechanically stable and has differently ordered needle microstructure. The crystalline structure and photoelectrochemical property of niobia film with the largest surface roughness were examined. The effect of CO2 gas bubbling, reflux and addition of 2-methoxyethanol on the hydrolysis of Nb(OEt)5 and the nature of the Nb2O5 films is also discussed. 相似文献
76.
Chu-Fang Wang Cheng-Hsiung Ke Jenq-Yann Yang 《Journal of Radioanalytical and Nuclear Chemistry》1993,173(1):195-203
Tea has been one of the most popular simulating beverages which is both heavily produced and consumed in Taiwan. The determination of minor or trace elements in drinking tea and tea leaves is therefore important for estimating the daily intake of Taiwanese considered as a safety indicator. In order to accurately and precisely determine the concentrations of trace elements in samples, several analytical methods such as AAS, NAA and ICP-AES are suggested. This paper attempts to utilize all three methods to determine the concentrations of minor or trace elements in different types of tea leaves and the extracts percolated from them. The influence of fermentation processes on the concentration levels of minor or trace elements in tea samples is investigated. Because only free metal ions are bioavailable for the human body, it is necessary to determine their concentrations in drinking tea. The dissolution of trace elements in drinking tea is therefore studied by simulating the common Chinese style of tea percolation. Concentrations of thirteen elements including Zn, Mn, Ca, Cu, Ni, Al, K, Mg, Cd, Pb, Na, Co and Sc are determined. 相似文献
77.
《Radiation Physics and Chemistry》2007,76(3):483-486
Secondary electrons, formed in biological tissues by high-energy particle impact, significantly contribute to the fragmentation of small molecules and to single- and double-strand brakes in DNA. Differential spectra of electrons emitted in the collisions of decelerating swift ions are of vital importance for estimating ion impact radiation damages. We demonstrate that the so-called Fermi-shuttle-type acceleration mechanism can produce a significant enhancement in the emission of high-energy secondary electrons. Double differential cross-sections for electron emission, measured in the collisions of N+ and N2+ ions with Ar targets at 750 keV/u impact energy, clearly show this effect. The measured cross-sections are in good agreement with the theoretical results of CTMC calculations. Multiple scattering contribution to the Ar spectra above 300 eV is proved to be significant. 相似文献
78.
A modification of the procedure reported byJohnson andWalseth
1 for the preparation of (-32P)ATP:(-32P)GTP with a specific activity of more than 5000 Ci/mmol was made firstly, then it was used as the phosphate donor in the reaction catalyzed by the polynucleotide kinase, to transfer its radioactive phosphate to the 5-position of the 3-AMP, resulting (5-32P)3-ADP. After that, (5-32P)3-ADP was hydrolysed to (5-32P)AMP under the catalysis of Nuclease P1, the late was then phosphorylated to produce (-32P)ATP by the action of myokinase and pyruvate kinase. By this method, we firstly prepared (-32P)ATP with a specific activity of more than 4000 Ci/mmol which was measured by HPLC analysis. 相似文献
79.
《Radiation Physics and Chemistry》2007,76(2):204-208
Positron annihilation lifetime spectroscopy (PALS) based on a pulsed slow positron beam was applied to study mesoporous silica films, synthesized using amphiphilic PEO–PPO–PEO triblock copolymers as structure-directing agents. The pore size depends on the loading of different templates. Larger pores were formed in silica films templated by copolymers with higher molecular-weights. Using 2-dimensional PALS, open porosity of silica films was also found to be influenced by the molecular-weight as well as the ratio of hydrophobic PPO moiety of the templates. 相似文献
80.
A method for the determination of fluoride by reversed-phase, high-performance liquid chromatography (RP-HPLC) is described. Fluoride, La3+ and alizarin complexone form F-La3+-alizarin complexone ternary complex, which is separated from the matrix on a RP, Ultrasphere C18 column (250 × 4.6 mm, 5 μm) using methanol-water (19:81, v/v) mobile phase at 1.00 mL min?1; detection at 568 nm. The calibration graph was linear from 1.0–150 ng mL?1 for fluoride with a correlation coefficient: 0.9993 (n=6). The detection limit was 0.2 ng mL?1. The method was successfully applied to the determination of fluoride in river and tap water. Recovery was: 94–102%, RSD in the range: 1.9 –3.6%. 相似文献