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11.
1. Contrary to the observations of earlier workers, it has been shown that formic acid can be quantitatively oxidixed by ceric sulphate in the presence of concentrated sulphuric acid. 2. Tartaric, malonic, malic and glycolic acids can also be oxidized completely to carbon dioxide and water by the following general procedure : to a known amount of the organic acid is added ceric sulphate (excess) solution in dilute sulphuric acid and the mixed solution refluxed for ten to fifteen minutes. Concentrated sulphuric acid (double the volume of the reaction mixture) is then added taking care that formic acid is not lost during the addition, and the mixture again refluxed for 45 to 50 minutes. The excess ceric sulphate is determined by titrating against ferrous ammonium sulphate. 3. The complete oxidation of the above acids provides satisfactory methods for their quantitative estimation. 相似文献
12.
13.
Allaf AW 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(7):1499-1503
Gas-phase infrared spectra of polyphosphazenes (phosphonitrilic halides trimer), (NPX2)3 where X=F, Cl and Br have been recorded. The molecules were generated for the first time by an on-line process using solid (NPCl2)3 as a precursor passed over heated sodium fluoride and potassium bromide at about 550 and 700 degrees C for (NPF2)3 and (NPBr2)3 production, respectively. The products were characterized by the infrared spectra of their vapors. The low-resolution gas-phase Fourier transform infrared spectra reported for the first time show strong bands centered at 1295, 1215 and 1200 cm-1, assigned to nu7(E'), in plane PN stretching mode of (NPX2)3, where X=F, Cl and Br, respectively. 相似文献
14.
n-Propyl tin trichloride and its complexes with bases as pyridine, α, β-and γ-picolines, isoquinoline, piperidine, morpholine, aniline and benzylamine have been prepared. The complexes have been characterised by their I.R. and molar conductance measurements. Assignments for some I.R. frequencies have been reported and discussed. Molar conductance values of some of the complexes in nitrobenzene categories them to be uni-univalent electrolytes. 相似文献
15.
Abstract— The relationship between energy metabolism and UV-induced (251 nm) DNA repair has been investigated in leukocytes obtained from peripheral blood of chronic myeloid leukaemia patients. Energy supply was modulated by using inhibitors of respiratory (antimvcin-A) and glycolytic (2-deoxy-o-glucose and other glucose analogues) pathways for adenosine-triphosphatc (ATP) production. DNA repair was measured by the unscheduled DNA synthesis technique. Parameters of energy metabolism like glucose utilization. lactate production and ATP content of cells. were measured under similar experimental conditions. The observations made indicate the following results: (1) ATP for DNA repair can be supplied by the respiratory and/or by the glycolytic pathway. (2) In the absence of respiration, the rate of glycolysis bears a linear correlation with DNA repair. (3) A minimum threshold rate of ATP-production is necessary for DNA repair. 相似文献
16.
Raman spectra of NaNO2 have been studied as a function of hydrostatic pressure to 40 kbar at 295 and 348 K. Slight changes in slope of mode frequency versus pressure plots support the view that a structural anomaly exists at 9 ± 1 kbar. The absence of qualitative changes in the Raman spectra allow the space group of NaNO2 IV to be specified as one of P1, P2, B2, Pm or Bm. The Raman spectrum of NaNO3 has been studied to 87 kbar. The changes observed are fully consistent with a second-order transition to a phase with symmetry C63v, as indicated by previous X-ray work, although the transition is sluggish. 相似文献
17.
18.
Pentafluoropyridine has been analysed in the frequency range of 8 to 18 GHz at dry ice temperature, using a conventional 100 kHz Stark modulated microwave spectrometer. The rotational constants and centrifugal distortion constants are A = 1481.539 ± 0.003 MHz, B = 1075.348 ± 0.004 MHz and C = 623.101 ± 0.001 MHz; and dJ = ?0.39 ± 0.06 kHz, dJK = 1.86 ± 0.27 kHz, dK = 0.70 ± 0.1 kHz, dEJ = (0.3 ± 0.03) × 10?6 and dEK = (?1.5 ± 0.2) × 10?6. The electric dipole moment has been found to be 0.98 ± 0.08 D and the values of the quadrupole coupling constants are xaa = 1.94 ± 0.22 MHz, xbb = ?4.08 ± 0.06 MHz and xcc = 2.14 ± 0.22 MHz. A simple analysis based on Townes and Dailey theory points to a considerable increase in the π-electron density and excess charge on the nitrogen site. 相似文献
19.
Ghadwal Rajendra Singh Sharma Malti Singh Anirudh Mehrotra Ram C. 《Transition Metal Chemistry》2004,29(4):419-424
Complexes of the types VO(L)(R-deaH), VO(R-dea)(LH), and VO(L)(OGOH)[L = deprotonated form of N-(1-hydroxyethyl) naphthaldimine; R-dea = deprotonated form of a N-substituted diethanolamine, with R = H or Ph; G = CH2CH2, CHMeCHMe, CMe2CMe2, CHMeCH2CMe2, CMe2CH2CH2CMe2] have been prepared by the equimolar reactions of VO(OPr
i
)3, LH2, and an appropriate diethanolamine or glycol in benzene. All of these coloured solid complexes have been characterised by elemental (C, H, N, and V) analyses and by spectroscopic (i.r., electronic, 1H-, 51V-n.m.r) studies. The relative lability of the hydroxy group(s) of N-(1-hydroxyethyl)naphthaldiamine, diethanolamine, and glycol has also been investigated. 相似文献
20.
B. B. Sharma 《Czechoslovak Journal of Physics》1979,29(11):1185-1188
This paper presents a numerical solution for an isotropic elastic circular plate. Effects of shear and rotatory inertia are included in a manner analogus to Timoshenko's one dimensional theory of bars. Matrix method has been employed to solve the set of equations obtained by using finite difference approximations. The use of IBM 1620 Computer was made for the computation of results showing thereby that even small machines could be used to handle the problem by the suggested approach.Notation 2
the Laplace two dimensional operator
-
h
thickness of plate
-
a
diameter of plate
-
v
Poisson's ratio
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E
Young's modulus of elasticity
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G
shear modulus
-
G
K
2
E/2(1 +v)
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K
a constant
-
density of the plate material
-
q
superimposed normal load per unit plate area
-
D
Eh
3/12(1–v2)
-
deflection of a point normal to the plane of plate
-
W
amplitude of harmonic deflection
-
M
amplitude of harmonic moment 相似文献