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1.
de Farias RF de Souza JM de Melo JV Airoldi C 《Journal of colloid and interface science》1999,212(1):123-129
The effects exhibited by adsorbed conducting polyaniline on the redox process on a molybdenum oxide surface were studied. Thermogravimetric results indicate a 4% polyaniline deposition. Cyclic voltammograms of the adsorbed polymer on MoO3 show that polyaniline exerts remarkable effects on the molybdenum blue oxidation-reduction process, with oxidation and reduction potentials of 0.33 and 0.18 V, respectively. This effect strongly enhances the electrode response, and can be used as an important tool in qualitative and/or quantitative determinations of molybdenum in solution as well as in any substrate. Copyright 1999 Academic Press. 相似文献
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A. Abdoulaye S. S. Soulayman G. Chabanis J. C. Giuntini J. V. Zanchetta I. Brach 《Ionics》1996,2(1):39-45
On the basis of experimental measurements of the electrical conductivity of the Nafaujasite zeolites (NaY), treated under
vacuum up to 673 K for 24 hours, we clearly demonstrate that the behavior of the measured conductivity σac of the dehydrated zeolite NaY, over an interval of high frequency change, may be described by a power-law function: σac=A▹s. The exponent s, in this case, should be considered as temperature and frequency dependent when the parameter A is a temperature
dependent function. On the other hand, when considering the measured conductivity as a sum of two terms (σac=σ0+σ′(▹)) resulting from the contributions of the dc and the ac components respectively, we find that one of them obeys the
Arrhenius law while the other can be expressed as A▹s. Parameter s is practically frequency independent when the frequency of the applied electrical field is higher than a characteristic
value ▹c A comparison with the measurements performed on NaY dehydrated at 435 K is also included.
Paper presented at the 2nd Euroconference on Solid State Ionics, Funchal, Madeira, Portugal, Sept. 10–16, 1995 相似文献
4.
Vara Prasad JV 《Organic letters》2000,2(8):1069-1072
[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity. 相似文献
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R. Rimet R. Buder C. Schlenker R. Roques J.V. Zanchetta 《Solid State Communications》1981,37(9):693-697
The α and β phases of MnGa2S4-α and β have been prepared and characterized. Single crystals of the α-phase have been grown by the vapor phase transport method ; their structure found monoclinic, space group C 2/c, has been refined by the X-ray technique and the positional and thermal parameters are reported. Both compounds are antiferromagnetic with Néel temperatures of 23.5 K and 11 K, for α and β respectively. EPR spectra show a single line, exchange-narrowed at 300 K, with a strong critical broadening above TN. These results are discussed in relation with the crystal structure and the possible superexchange interactions between the Mn2+. 相似文献
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A Continuous-Wave Ho:YA103 Laser with Output 8.5 W Pumped by a 1.91μm Laser at Room Temperature 下载免费PDF全文
A cw high efficient Ho:YAI03 laser pumped by 1.91 μm diode-pumped Tm:YLF laser at room temperature is realized. The maximum output power reaches 8.5 W when the incident pump power is 15.6 W. The slope efficiency is 63.7%, and the Tm:YLF to Ho:YAP optical conversion efficiency is 54.5%. The laser wavelength is 2118.3nm when the transmission of output coupler is 30%. The beam quality factor is M2 -1.39 measured by the traveling knife-edge method. 相似文献
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G. Chabanis V. Mouton A. Abdoulaye J. C. Giuntini J. V. Zanchetta J. Vanderschueren 《Ionics》1995,1(2):177-182
We report the study of the dielectric relaxation mechanisms in the zeolite Na-X, “Faujasite”, by means of the method of Thermally
Stimulated Depolarization Currents (TSDC), and polarization conductivity versus frequency. We give particular interest to
the effect of adsorption on the evolution of dielectric parameters. Two distinct relaxation processes attributed to adsorbed
water were found by TSDC measurements. Moreover, the polarization conductivity gives two sets of values of the potential barrier
height. The evolution of the polarization conductivity as a function of the rate p/p° is comparable to the curve showing the
isothermal water adsorption.
Paper presented at the 1st Euroconference on Solid State Ionics, Zakynthos, Greece, 11–18 Sept. 1994 相似文献
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The ac dielectric response obtained on a set ofxAgI-(1−x)AgPO3 samples (x=0.15, 0.30 and 0.50) is analysed, using the Inverse and Ill-Posed Problem approach, in terms of a distribution
function of relaxation times. It is then shown that the shape of the distribution function becomes narrower and more symmetric
when both temperature T and the mobile cation content x increase. Although no quantitative model enables yet to explain this
new experimental fact and only qualitative speculations can be proposed, it opens new prospects for theoretical approaches.
Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998. 相似文献
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F. Salam J. Ch. Giuntini S. Sh. Soulayman J. V. Zanchetta 《Applied Physics A: Materials Science & Processing》1995,60(3):309-312
We clearly demonstrate, on the basis of experimental measurements of the electrical conductivity of (Ag2S)
x
-(GeS2)1-x
glasses, that the power-law behaviour of the polarization ac conductivity,
ac=A
s
, can be used. The exponents, in this case, should be considered as a function of temperature and frequency. Moreover, the parameters depends on details of the structure, i.e., the nature of disorder. 相似文献