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911.
Iftikhar Ahmad 《国际化学动力学杂志》1985,17(7):763-768
The kinetics and products of the decompositon of 9-diazofluorene by copper(II) tetrafluoroborate in acetonitrile solvent have been investigated. The reaction is first order with respect to both 9-diazofluorene and copper(II) tetrafluoroborate. A reaction mechanism has also been proposed. 相似文献
912.
The potential application of DONNAN dialysis to water softening has been studied. The selective transportation of calcium and alkaline-earth ions through a cationic membrane appeared to be an interesting process, since materials with both optimal exchange capacity and transportation properties exist now.
Preliminary investigations allowed us to optimize some of these materials, as well as the conditions of their use. Thus we have found that for the membranes handled, the 3.10-2 M concentration of brine represented the best compromise between the extraction of calcium and the leakage of chlorine through the membrane (relating to the water to be softened).
We also observed that for a low and a medium flow, the extraction rate was high enough to allow the release of calcium at a rate comparable to the classical ion-exchange process using a resin bed. 相似文献
913.
Zafar Ahmad Siddiqi Shahla Nusrat Qidwai Maimoona Jaria Mohd Shakir 《Transition Metal Chemistry》1988,13(4):244-246
Summary Reactions ofN-trimethylsilylimidazole andN-trimethyl-silyl-2-methylimidazole with CoCl2 yield chloro(imidazolato)cobalt(II), (1), or chloro(2-methylimidazolato)-cobalt(II), (2). However, the corresponding reactions of [Co(Ph3P)2Cl2] cause total removal of Ph3P along with the substitution of both the chlorine atoms yielding bis(imidazolato)cobalt(II), (3), or bis(2-methylimidazolato)cobalt(II), (4), in the form of light blue microcrystalline solids. The complexes have been characterized by elemental analysis, molecular weight, and magnetic susceptibility measurements, and i.r., reflectance and electronic spectra. The results are consistent with formulations as rare examples of two-coordinate cobalt(II) derivatives.Author to whom all correspondence should be directed 相似文献
914.
The 1H-n.m.r. signal of the drug (10–35 mg ml?1) in deuterium oxide, with maleic acid as internal reference standard, is used. The integral of the peak at 3.06 ppm with respect to 3-trimethylsilylpropionic acid is compared with that at 6.3 ppm for the internal standard. The method is quantitative and free from interference by tablet excipients. 相似文献
915.
S. Ahmad A. Mannan F. Nahid I. H. Qureshi 《Journal of Radioanalytical and Nuclear Chemistry》1992,158(1):201-210
Naturally available lateritic minerals (LM) have been used on laboratory scale for the removal of Ce, Gd and Lu radionuclides from nuclear industry and reactor effluents. The adsorption behavior using radiotracers is reported, describing factors such as the nature and strength of acids, particle size, temperature and equilibration time which influence the adsorption mechanism. The interference of various anions and organic complexing agents on sorption of these radiotracers has also been considered. The optimized physico-chemical conditions and high loading capacities suggest an, effective use of LM for the isolation of the radionuclides from industrial and reactor effluents. Leaching studies made on pelletized LM loaded with the radionuclides indicate their potential for disposal in reduced solid form for a longer period. 相似文献
916.
M. Siddique I. H. Gul I. Ahmad N. M. Butt 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(1):151-155
Fe-rich Nd-Fe-B permanent magnetic materials are of great technological interest because of their superior magnetic properties such as coercivity and large energy products. These properties can be further enhanced by the substitution of Nd or Fe. We are presenting the results of atomic replacement of iron by Ga, Dy, Nb and Si, in the base material N18Fe7 6B6, obtained by Mössbauer spectroscopy. It is observed that the net magnetization decreases for all compositions with the substitution of these elements. 相似文献
917.
Identifiability of finite mixtures using a new transform 总被引:2,自引:0,他引:2
Khalaf E. Ahmad 《Annals of the Institute of Statistical Mathematics》1988,40(2):261-265
Identifiability of finite mixtures of the following families of distributions are proved: Weibull, normal log, chi, pareto and power function. 相似文献
918.
A highly efficient gain-clamped L-band EDFA with improved noise figure characteristic is demonstrated by simply adding a broadband
C-band FBG in double-pass system. The combination of the FBG and optical circulator has created laser in the cavity for gain
clamping. By adjusting the power combination of pumps 1 and 2, the clamped gain level can be controlled. The amplifier gain
is clamped at 28.1 dB from −40 to −25 dBm with a gain variation of less than 0.5 dB by setting the pumps 1 and 2 at 59.5 and
50.6 mW, respectively. The gain is also flat from 1574 nm to 1604 nm with a gain variation of less than 3 dB. The corresponding
noise figure varies from 5.6 to 7.6 dB, which is 0.8 to 2.6 dB less than those of unclamped amplifier. 相似文献
919.
Hamdi M. Hassaneen Ahmed M. Farag Ahmad S. Shawali Mohamed S. Algharib 《Journal of heterocyclic chemistry》1987,24(3):577-580
The regioselectivity of the cycloadditions of α,β-unsaturated nitrilimine derived from N-phenylcinnamo-hydrazidoyl chloride 2 to C = Se, C = S and C = C double bonds of the resonance stabilized selenocyanate and thiocyanate anions, enol tautomer of dibenzoylmethane and benzalacetophenone was investigated. The results indicate that the reactions studied are dipole-LUMO-dipolarophile-HOMO controlled and that the larger orbital coefficient in the LUMO of N-phenylcinnamonitrilimine is on the carbon atom bearing the styryl group. The structures of the cycloadducts were assigned and confirmed on the basis of their elemental analyses and spectra. 相似文献
920.
Hafiz Ghulam Abbas Saeeda Asghar Maqbool Ahmad Shahid 《Journal of Radioanalytical and Nuclear Chemistry》1995,189(1):45-50
A method for labeling of anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAb) BW 431/26 is described. For preparations of99mTc-anti-CEA complex, a solution (1 ml) of tetrasodium-1,1,3,3-propanetetetraphosphate dihydrate (2.7 mg), stannous chloride dihydrate (0.12 mg) and sodium chloride (0.2 mg) in 5 ml of 0.9% saline was added to a vial containing monoclonal antibody (2 mg) from mouse (MAb BW 431/26), D-glucitol (2 mg) and sodium sulfate (2 mg) to obtain a clear solution. A quantitative labeling yield of the MAb BW 431/26 was achieved by addition of 5 ml (40.5 mCi, 1.5 Gbq) technetium-99m-pertechnetate (99mTcO4) generator eluate at room temperature within 10 minutes. The radiochemical purity determined by ITLC (Gelman, SG) plates was >95%. 相似文献