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71.
An automatic mass spectrometric method for the quantitation of N-acetylcysteine (NAC) in human plasma has been developed. NAC was extracted from plasma with ethyl acetate and derivatized in two steps with 2-propanol and pentafluoropropionic anhydride. The volatile derivative obtained was ideal for gas chromatographic-mass spectrometric analysis. Data obtained by analysing the plasma of healthy volunteers to whom 600 mg of NAC had been orally given are reported. 相似文献
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D. G. Elson 《The Journal of the Operational Research Society》1972,23(1):31-43
It is demonstrated that mixed-integer programming can be applied successfully to the solution of certain practical site location problems. A mixed-integer model of a frequently occurring form of warehouse location problem is presented. Experience with models of this type is described with examples of computational performance. The flexibility of mixed-integer models and the approach to their use as aids to decision-making are discussed. 相似文献
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Roberto Longo 《Reports on Mathematical Physics》1977,12(1):119-124
Given a C1 algebra , the generator of a group of automorphisms δ, and a derivation D, we examine some situations in which δ+λD is a generator for small real λ. 相似文献
77.
We report ab initio calculations of the structures, binding energies, and total spins of the clusters Ni(13), Ni(19), Ni(23), Ni(26), Ni(12)Fe, Ni(11)Fe(2), Ni(18)Fe, Ni(17)Fe(2), Ni(22)Fe, Ni(20)Fe(3), and Ni(25)Fe using a density-functional method that employs linear combination of atomic orbitals as basis sets, nonlocal norm-conserving pseudopotentials, and the generalized gradient approximation for exchange and correlation. Our results show that the Fe-doped Ni clusters, which have icosahedral or polyicosahedral ground-state structures similar to those of the corresponding pure Ni clusters, are most stable with the Fe atoms occupying internal positions, as has also been inferred from experimental results on the adsorption of molecular nitrogen on the cluster surfaces. We also rule out the possibility that the experimentally observed difference between the (nonpolyicosahedral) configurations of N(2)-saturated Ni(26) and N(2)-saturated Ni(25)Fe be due to the influence of the Fe atom on the energy of the underlying metal cluster. 相似文献
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