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91.
A.C. and d.c. electrical conductivities, thermoelectric power and dielectric constant of copper vanadate (CuV2O6) have been measured in the temperature range 300–1000 K in order to discuss the electrical conduction in the compound. The extrinsic conduction, which takes place below 500 K, has been explained by small polaron hopping mechanism while intrinsic conduction, which takes place above 500 K, has been explained by large polaron band mechanism in view of the values of activation energy and charge carrier mobility in the temperature ranges 300–500 K and 500–1000 K. 相似文献
92.
Chandra Raju 《Czechoslovak Journal of Physics》1986,36(12):1350-1357
In this paper, we show that 2m
e
m
/(m
e
2
+m
2
= (g
V/g
A)
e
2
. From this expression, the Weinberg mixing parameter is shown to be 0·2254 or 0·2746. Assuming that the electron and muon neutrino masses are degenerate, we find thatm
v = (g
V/g
A)
e
2
. (m
e
m
)/M
WL, where MWL is the mass of the standard W± boson. The neutrino mass turns out to be 6·5 eV. The -neutrino mass is found to be about 81 MeV. The masses of c, t, s and b quarks are found to be respectively 1·7 GeV, 21·2 GeV, 0·57 GeV and 2·18 GeV by assumingm
d=m
u= 0·3 GeV. All these masses agree with other estimates except the b quark which has about half of its expected value. 相似文献
93.
R. S. Tomar Prakash Bhartia 《International Journal of Infrared and Millimeter Waves》1986,7(9):1281-1295
New design data for an open suspended microstripline is reported. Two most commonly used substrate materials, namely RT-Duroid (r=2.22) and fused quartz (r=3.78) are considered. Effects of dispersion and strip thickness are included in the results which are based on a fullwave spectral-domain analysis. The data, which is computed over the complete practical ranges of frequency and parameter values, is much more reliable than the currently available quasistatic results. 相似文献
94.
The use of 1,2-naphthoquinone-2-semicarbazone-4-sulphonic acid and 1,2-naphtho-quinone-2-thiosemicarbazone-4-sulphoic acid as indicators in the titrimetric estimation of phosphate, molybdate, tungstate and sulphate with lead has been examined. The precision, accuracy and applicability of the methods have been evaluated. 相似文献
95.
[reaction: see text] Gamma,delta-unsaturated beta-diketones have been prepared by the acylation of ketones with N-acylbenzotriazoles of various aliphatic and aromatic alpha,beta-unsaturated carboxylic acids. 相似文献
96.
G.K. Surya Prakash 《Journal of fluorine chemistry》2002,117(2):103-105
1,3-Dehydroadamantane undergoes a facile reaction with tetrafluorohydrazine to give 1,3-bis(N,N-difluoroamino)adamantane, the product of 1,3-NF2 radical addition. 相似文献
97.
Summary The reversible complex formation between oxalatopentaammine cobalt(III), aluminium(III) and gallium(III) was investigated by the stopped flow technique at 30 ± 0.1 °C and I = 1.0 mol dm–3. The reactivity sequence: GaIII > AlIII is observed, however, the major path for gallium(III) was (NH3)5CoC2O4H2+ + GaOH2+ (NH3)5CoC2O4-Ga4+ + H2O. The formation and dissociation rate constants of the binuclear species have been compared with the analogous data for iron(III) and nickel(II) reported earlier. The results reflect the fact that the half-bonded exalato moiety of (NH3)5CoC2O
inf4
p+
acts as a chelating agent for the metal ions.Author to whom all correspondence should be directed. 相似文献
98.
Two bis(bipyridine) polymeric metal nitrate complexes
with 4,4’-bipyridine of simple formula like [M(bipy)2](NO3)2⋅xH2O (where M=Co, Ni and Cu; x=4, 2 and 0, respectively) have been prepared and
characterized. Their thermal decomposition has been undertaken using simultaneous
TG-DTG-DTA and DSC in nitrogen atmosphere and non-isothermal TG in air atmosphere.
Isothermal TG has been performed at decomposition temperature range of the
complexes to evaluate the kinetics of decomposition by applying model-fitting
as well as isoconversional method. Possible mechanistic pathways have also
been proposed for the thermolysis. Ignition delay measurements have been carried
out to investigate the response of these complexes under the condition of
rapid heating. 相似文献
99.
Cloud point (C(P)) was measured for ternary mixtures of different ionic surfactants such as sodium dodecyl sulfate (SDS), dodecyltrimethylammonium bromide (DTAB), and dimethylene bis(dodecyldimethylammonium bromide) (12-2-12) plus triblock polymer (TBP) ((PEO)(2)(PPO)(15.5)(PEO)(2)) plus water, keeping the concentration of TBP constant and varying the surfactant concentration from pre- to postmicellar regions. These experiments were also performed in the presence of different fixed amounts of NaBr to evaluate the salt effect on the clouding behavior of these ternary mixtures. The C(P) value of TBP exhibits a drastic change at the cmc of each surfactant. The cmc values thus obtained both in the absence and in the presence of NaBr were used to evaluate counterion binding (beta) with the Corrin-Harkins method. beta values were also used to evaluate the thermodynamic parameters of these ionic surfactants. The results suggest that the beta values evaluated using this method, especially at low [TBP], are in good agreement with those reported in the literature. 相似文献
100.
NMR spectroscopic studies reveal that binding of Na(+) by tris(2-methoxyphenyl)amine (3) brings two of these tripod ethers together about the metal ion; the related double-tripod-ether ionophore 1,2-bis[2-(bis(2-methoxyphenyl)amino)phenoxy]ethane (4), in which two triarylamines are covalently attached, binds LiI, LiBPh(4), NaI, NaBPh(4), and KB(4-ClPh)(4). Dynamic NMR puts lower limits on binding free energies of 4 for Na(+) (71.8 kJ mol(-)(1)) and K(+) (66.8 kJ mol(-)(1)) ions. X-ray studies of 3(2).NaBPh(4), 4.NaBPh(4), 4.NaB(4-ClPh)(4), and 4.KB(4-ClPh)(4).CH(3)NO(2) show eight-coordinate M(+) ions bound between crystallographically independent, homochiral triarylamine tripod ethers in structures reminiscent of alkali metal [2.2.2] cryptates. Complexes crystallize as follows: 3(2).NaBPh(4), monoclinic, P2(1)/c, Z = 4, a = 10.701(3) ?, b = 37.593(3) ?, c = 13.774(2) ?, and beta = 98.24(2) degrees; 4.NaBPh(4), triclinic, P&onemacr;, Z = 2, a = 12.157(1) ?, b = 14.811(1) ?, c = 15.860(2) ?, alpha = 105.400(8) degrees, beta = 91.594(9) degrees, and gamma = 95.354(8) degrees; 4.NaB(4-ClPh)(4), monoclinic, P2(1)/n, Z = 4, a = 13.652(5) ?, b = 18.75(1) ?, c = 22.805(5) ?, and beta = 92.21(5) degrees; 4.KB(4-ClPh)(4).CH(3)NO(2), monoclinic, Pn, Z = 2, a = 13.663(4) ?, b = 12.228(3) ?, c = 18.712(8) ?, and beta = 91.45(3) degrees. They show variable N-M-N angles; 3(2).NaBPh(4) is surprisingly bent ( angleN-Na-N = 154.5 degrees ), while the 4.M(+) complexes are normal: nearly linear for Na(+) ( angleN-Na-N = 178.6, 178.1 degrees ) and again bent with the larger K(+) ( angleN-K-N = 164.5 degrees ). Finally, free 4 is structurally similar to 3; it crystallizes in the triclinic space group P&onemacr;, with Z = 2, a = 8.068(1) ?, b = 14.599(2) ?, c = 16.475(3) ?, alpha = 115.43(1) degrees, beta = 92.51(1) degrees, and gamma = 90.40(1) degrees. 相似文献