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61.
N. I. Foster R. Dannals H. D. Burns N. D. Heindel 《Journal of Radioanalytical and Nuclear Chemistry》1981,65(1-2):95-105
Pyrrolidyl triazenes prepared by interception of the diazonium transient in the Sandmeyer reaction of amines can serve as
useful intermediates in the iodination and radioiodination of aryl rings. Decomposition of such triazenes in the presence
of iodide is acid-catalyzed and is sensitive to choice of solvent, acid, and triazene structure. A condition variation study
by HPLC of four different solvent systems and two non-nucleophilic acids was carried out on the123I iodination of the triazenes of p-nitroaniline, p-anisidine and p-toluidine. This method has proven useful in radiolabeling
of two pharmaceutical analogs which were not amenable to labeling through the classic Sandmeyer method. 相似文献
62.
We report measurements of the optic index of reflection as a function of temperature, n(T), for several highly disordered ferroelectrics: PLZT ceramic [Pb1?xLax(Zr0.65Ti0.35)1?x/4O3 where x = 0.08] and single crystals of Pb3(MNb2)O9 where M = Zn and Mg. The results are qualitatively different from the unusual displacive ferroelectric behavior and the difference is clearly due to local disorder. 相似文献
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66.
Summary Interference with the lead plate test for fluoride by borate and fluoborate can be eliminated by applying tests for silica and borate to the water drop, these tests allowing positive identification of the presence of silica and borate in the sample.
Part XX: Mikrochim. Acta [Wien]1964, 790. 相似文献
Zusammenfassung Die durch Borat und Fluoborat verursachte Störung des Fluoridnachweises nach dem Bleiplattenverfahren läßt sich durch Prüfung auf Kieselerde und Borat im Wassertropfen vermeiden, deren Anwesenheit in der Probe hiermit eindeutig feststellbar ist.
Résumé On peut éliminer l'interférence des fluorures avec les borates et les fluoborates dans l'essai à la lame de plomb en effectuant la recherche de la silice et des borates sur une goutte d'eau, ce qui permet l'identification positive de la présence de silice et de borate dans l'échantillon.
Part XX: Mikrochim. Acta [Wien]1964, 790. 相似文献
67.
A diode-pumped Nd:KGd(WO4)2 laser mode locked by a saturable Bragg reflector (SBR) is passively stabilized to suppress Q-switched mode locking and to extend the parameter range of continuous-wave mode locking. An indium phosphide plate exhibiting two-photon absorption and free-carrier absorption is used for passive stabilization. The intracavity pulse energy for the onset of stable continuous-wave mode locking is reduced by a factor of 4 compared with the laser without stabilization. By increasing the modulation depth of the SBR, pulse shortening by 30% is achieved and bandwidth-limited 6.2-ps pulses are measured. 相似文献
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This paper presents an application of a monomial approximation method for solving systems of nonlinear equations to the design of civil engineering frame structures. This is accomplished by solving a set of equations representing the state known as fully-stressed design, where each member of the structure is stressed to the maximum safe allowable level under at least one of the loading conditions acting on it. The monomial approximation method is based on the process of condensation, which has its origin in geometric programming theory. A monomial/Newton hybrid method is presented which permits some of the design variables to be free in sign, while others are strictly positive. This hybrid method is well suited to the structural design application since some variables are naturally positive and others are naturally free. The proposed method is compared to the most commonly used fully-stressed design method in practice. The hybrid method is shown to find solutions that the conventional method cannot find, while doing so with less computational effort. The impact of this approach on the activity of structural design is discussed. 相似文献
70.
An improved spectral editing method for solids is described which allows one to obtain a set of subspectra in roughly two-thirds the amount of time as our original CPPI editing method for the same signal to noise. This improvement is afforded by a new pulse sequence that is used to acquire a (13)CH + (13)CH(2) spectrum which has very little (13)CH(3) or nonprotonated carbon contamination. By using this new sequence the (13)CH-only subspectrum is obtained much more efficiently. Criteria for optimizing the signal to noise in the edited subspectra are discussed. Copyright 2000 Academic Press. 相似文献