Separation and quantitative determination of the cerium group lanthanides by gas-liquid chromatography

A gas chromatographic method is reported for the separation and subsequent quantitative determination of the cerium group lanthanides. The lanthanides (RE) are synergistically extracted from aqueous solution with the polyfluorinated beta-diketone 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione, H(FHD), as ligand, and di-n-butylsulphoxide, DBSO, as neutral donor. The composition of the extracted species is reported to be RE(FHD)(3) .2DBSO. Thermogravimetric analysis of the complexes is reported. Analytical curves were prepared and found to be usable over the range of 0.1-10 mug of metal. Individual lanthanides were determined with 99.0 % recovery with a relative mean deviation of +/-2.0%. Mixture of lanthanides were analyzed with 101.2% recovery with a relative mean deviation of +/-2.2%.     

Tea CO2 laser-induced deuterium exchange in the ammonia—fluoroform-d system

Vibrational excitation of CDF₃ and NH₃ at 970 cm^?1 by a TEA CO₂ laser results in deuterium—hydrogen exchange suppressing the IR-laser-induced multiphoton chemistry of CDF₃.     

The isomers of Si2H4: disilene and silylsilylene

Geometries and relative energies of the lowest singlet and triplet states of disilene and silylsilylene have been investigated using ab initio SCF and CI methods. At the most reliable level of theory employed, singlet disilene is predicted to be 8–10 kcal/mol more stable than singlet silylsilylene.     

Some Algebras Similar to the Enveloping Algebra of s1(2)

Abstract

Consider the algebra R = ?[A,B,H] subject to relations

where and . We study these algebras for different f and ç. We study highest weight modules and finite dimensional simple modules. We introduce the categories ^p with p ≥ 1, with an interesting decomposition in categories ^p _I and ^p _II . We also consider the BGG-category and develop new techniques towards the study of .     

Parametric analysis of four wave mixing in DWDM systems

The developments made over the years in WDM (Wavelength Division Multiplexing), on one side, produced compensation of increasing traffic and channel capacity, but on other side, pertinently caused WDM systems to undergo different linear and non-linear effects thereby degrading the performance as such. To overcome linear effects is relatively convenient and manageable, however, the non-linear effects including four wave mixing (FWM) is not only difficult to eliminate but also highly incompatible from system point of view. In this research, valid parameters which lead to generation and enhancement of FWM, are discussed, simulated and based on exhaustive sets of obtained results, a detailed analysis has been carried out to reduce the FWM. The simulated results obtained by exploiting nine important parameters using Optisys simulator, divulge very incisive information for the removal of nonlinear effects in WDM. The authors are reasonably confident to extend their results as a contribution in the subject area.     

Performance enhancement of Absolute Polar Duty Cycle Division Multiplexing with Dual-Drive Mach-Zehnder-Modulator in 40 Gbit/s optical fiber communication systems

We modeled and analyzed a method to improve receiver sensitivity of the Absolute Polar Duty Cycle Division Multiplexing (AP-DCDM) transmission system by using Dual-Drive Mach-Zehnder-Modulator (DD-MZM). It is found that by optimizing the bias voltage in DD-MZM, the sensitivity of the AP-DCDM can be improved. The optimizations lead towards the larger eye opening. As opposed to the previous work, in terms of receiver sensitivity and dispersion tolerance, similar performance for all channels was achieved. In comparison to the previously reported AP-DCDM system, this work resulted in almost 3.6 dB improvement of the receiver sensitivity, came together with acceptable chromatic dispersion tolerance.