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71.
A new on-line Gd preconcentration and determination system associated to flow injection (FI) method was developed. 2,2′-(1,8-dihydroxy-3,6-disulfonaphthylene-2,7-bisazo) bisbenzenearsonic acid (Arsenazo III) was used as a complexing agent at pH 2.5. A reactor containing the polyamide membrane was used for the retention of the Gd complex by chemofiltration. The complex was then removed from the reactor with buffer solution pH 9. The variables affecting the combined on-line preconcentration-absorptiometric method have been evaluated and optimised. The coupling of the on-line preconcentration and spectrophotometric flow through detection led to a detection limit of 15 μg l−1 for a preconcentration time of 5 min at 2 ml/min. The method was successfully applied to biological samples. 相似文献
72.
Plasma treatments in Radio Frequency Glow Discharges fed with NH3−H2 mixtures have been performed for modifying polyethylene surfaces. Treatment kinetics and the role of species present in the
glow have been investigated. Actinometric Optical Emission Spectroscopy has been utilized as a plasma diagnostic technique.
Electron Spectroscopy for Chemical Analysis has been utilized for studying surface composition of treated substrates, which
have been examined both astreated and after derivatization of amine-functionalities with 4-trifluoromethylbenzaldehyde vapors.
It has been found that experimental plasma parameters and plasma density of active species can be controlled to achieve selective
grafting of-NH2 among all other nitrogen-containing groups. 相似文献
73.
The Team Orienteering Problem (TOP) is the generalization to the case of multiple tours of the Orienteering Problem, known
also as Selective Traveling Salesman Problem. A set of potential customers is available and a profit is collected from the
visit to each customer. A fleet of vehicles is available to visit the customers, within a given time limit. The profit of
a customer can be collected by one vehicle at most. The objective is to identify the customers which maximize the total collected
profit while satisfying the given time limit for each vehicle. We propose two variants of a generalized tabu search algorithm
and a variable neighborhood search algorithm for the solution of the TOP and show that each of these algorithms beats the
already known heuristics. Computational experiments are made on standard instances. 相似文献
74.
75.
Vito Di Noto Lucia A. Magrì Maria Viviani Carla Marega Antonio Marigo Roberto Zannetti 《Journal of chemical crystallography》1992,22(1):59-64
FT-IR Spectroscopy with total attenuated reflectance (ATR) was used for the quantitative determination of ethyl formate coordinated in inorganic matrices such as magnesium chloride. The spectra were recorded directly on solutions obtained by dissolving the inorganic Ziegler-Natta supports in water. The method proposed is sensitive and rapid and appears to be very reliable when compared with other methods, such as solvent extraction followed by gaschromatographic or thermogravimetric analysis. 相似文献
76.
77.
G. Cassinelli E. De Vito A. Levrero 《Journal of Mathematical Analysis and Applications》1997,210(2):472
We classify all the decompositions of a quantum state as a weighted sum of one dimensional projectors. In particular we describe explicitly the set of irreducible decompositions. The physical interest in this problem rests on the possibility of interpreting the decomposition in terms of a classical mixture. 相似文献
78.
Any sequence of legal moves leads the Towers of Hanoi puzzle to an arrangement from which the final configuration must be built up. A recursive algorithm which finishes off the puzzle is considered and, assuming a uniform distribution on the possible unfinished situations, the density function of the number of moves it takes is derived. 相似文献
79.
80.
Luciano De Vito 《Archive for Rational Mechanics and Analysis》1959,3(1):60-81
Memoria presentata da G. Fichera 相似文献