Fitness based Differential Evolution

Differential Evolution (DE) is a well known and simple population based probabilistic approach for global optimization. It has reportedly outperformed a few Evolutionary Algorithms and other search heuristics like Particle Swarm Optimization when tested over both benchmark and real world problems. But, DE, like other probabilistic optimization algorithms, sometimes exhibits premature convergence and stagnates at suboptimal point. In order to avoid stagnation behavior while maintaining a good convergence speed, a new position update process is introduced, named fitness based position update process in DE. In the proposed strategy, position of the solutions are updated in two phases. In the first phase all the solutions update their positions using the basic DE and in the second phase, all the solutions update their positions based on their fitness. In this way, a better solution participates more times in the position update process. The position update equation is inspired from the Artificial Bee Colony algorithm. The proposed strategy is named as Fitness Based Differential Evolution ( $FBDE$ ). To prove efficiency and efficacy of $FBDE$ , it is tested over 22 benchmark optimization problems. A comparative analysis has also been carried out among proposed FBDE, basic DE, Simulated Annealing Differential Evolution and Scale Factor Local Search Differential Evolution. Further, $FBDE$ is also applied to solve a well known electrical engineering problem called Model Order Reduction problem for Single Input Single Output Systems.     

Time-Domain Quantification of Multiple-Quantum-Filtered Na Signal Using Continuous Wavelet Transform Analysis

The application of continuous wavelet transform (CWT) analysis technique is presented to analyze multiple-quantum-filtered (MQF) ²³Na magnetic resonance spectroscopy (MRS) data. CWT acts on the free-induction-decay (FID) signal as a time-frequency variable filter. The signal-to-noise ratio (SNR) and frequency resolution of the output filter are locally increased. As a result, MQF equilibrium longitudinal magnetization and the apparent fast and slow transverse relaxation times are accurately estimated. A developed iterative algorithm based on frequency signal detection and components extraction, already proposed, was used to estimate the values of the signal parameters by analyzing simulated time-domain MQF signals and data from an agarose gel. The results obtained were compared to those obtained by measurement of signal height in frequency domain as a function of MQF preparation time and those obtained by a simple time-domain curve fitting. The comparison indicates that the CWT approach provides better results than the other tested methods that are generally used for MQF ²³Na MRS data analysis, especially when the SNR is low. The mean error on the estimated values of the amplitude signal and the apparent fast and slow transverse relaxation times for the simulated data were 2.19, 6.63, and 16.17% for CWT, signal height in frequency domain, and time-domain curve fitting methods, respectively. Another major advantage of the proposed technique is that it allows quantification of MQF ²³Na signal from a single FID and, thus, reduces the experiment time dramatically.     

Heterobimetallic heterocyclic derivatives of indium(III)

Reactions of InCl₃ with potassium salts of bifunctional tridentate (L¹H₂HOC₆H₄CH NCH₂CHMeOH) and monofunctional bidentate (L²HHOC₆H₄CHN-i-Bu) Schiff bases in 1:1 and 1:2 molar ratio in benzene afford complexes In(L¹)Cl and In(L²)₂Cl, respectively. On reaction with potassium isopropoxymetallates KB(O-i-Pr)₄, KAl(O-i-Pr)₄, KTi(O-i-Pr)₅, and KNb(O-i-Pr)₆, they produce interes- ting heterobimetallic heterocyclic complexes. These are characterized by elemental (N, B, Al, Ti, and Nb) analyses, molecular weight measurements, and spectral [IR, NMR (¹H, ¹³C, ¹¹B, and ²⁷Al)] studies. Probable structures are suggested for them. © 2003 Wiley Periodicals, Inc. 15:21–25, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.hc10206     

1‐(2‐Hydro­xy‐4‐methoxy­phenyl)‐3‐(2,3,4‐tri­methoxy­phenyl)­prop‐2‐en‐1‐one

The title compound, C₁₉H₂₀O₆, crystallizes in the centrosymmetric space group P2₁/c with one mol­ecule in the asymmetric unit. The mol­ecule is approximately planar and the dihedral angle between the phenyl rings is 11.0 (1)°. The H atoms of the central propenone group are trans. There is an intramolecular O—H⃛O hydrogen bond and the mol­ecules are crosslinked by four intermolecular C—H⃛O hydrogen bonds, producing a three‐dimensional network.     

Aqueous Precursor Induced Morphological Change and Improved Water Stability of CsPbBr3 Nanocrystals

In the literature, lead halide perovskites are very notable for their degradation in the presence of polar solvents, such as water. In contrast, in this research, it is observed that adding a minor amount of water into the precursor solution can improve the stability and photoluminescence quantum yield of CsPbBr₃ nanocrystals through a ligand-assisted reprecipitation (LARP) method. In this way, the shape and phase transformation from CsPbBr₃ nanoplates to CsPbBr₃/Cs₄PbBr₆ nanorods and Cs₄PbBr₆ nanowires can be controlled with increasing water content in the precursor solution. Upon adding water up to an ideal amount, CsPbBr₃ maintains its phase and nanoplate morphology. The key role of water amount for tuning the crystallinity, stability, morphology, optical properties, and phase transformation of cesium lead halide perovskite nanocrystals will be beneficial in the future commercialization of optoelectronics.     

Low energy excitations in spin glasses

We discuss the nature of excitations that govern the low temperature thermodynamic behaviour of spin glasses and propose that the spin glass state is a space-time dependent ground state of a system of interacting spins wherein rotational invariance is broken spontaneously.     

Bayes estimation of number of signals

Bayes estimation of the number of signals, q, based on a binomial prior distribution is studied. It is found that the Bayes estimate depends on the eigenvalues of the sample covariance matrix S for white-noise case and the eigenvalues of the matrix S ₂ (S ₁+A)^–1 for the colored-noise case, where S ₁ is the sample covariance matrix of observations consisting only noise, S ₂ the sample covariance matrix of observations consisting both noise and signals and A is some positive definite matrix. Posterior distributions for both the cases are derived by expanding zonal polynomial in terms of monomial symmetric functions and using some of the important formulae of James (1964, Ann. Math. Statist., 35, 475–501).     

Laser-induced damage in InSb at 1.06 μm wavelength—a comparative study with Ge, Si and GaAs

This paper deals with the study of laser-induced damage in n-type single crystal InSb irradiated with a Nd: glass laser of 1.06 μm wavelength and 300 μs pulse duration. Samples of different surface quality were prepared by mechanical lapping and polishing by diamond paste. Evolution of damage morphological features observed at different power densities is discussed. Damage threshold results are analysed in terms of a thermal model taking into account the temperature dependence of various physical parameters and using the finite difference method of calculation. A comparative study of laser induced damage in InSb, Ge, Si and GaAs irradiated under similar conditions is also presented.     

Spectrophotometric determination of palladium after coprecipitation of its 9,10-Phenanthrenequinone monoximate on microcrystalline naphthalene

Summary A spectrophotometric method has been developed for the microdetermination of Pd(II) as its 9,10-Phenanthrenequinone monoximate, by coprecipitation on solid naphthalene and dissolution in chloroform. The method can be applied to the determination of palladium in certain synthetic mixtures.

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Spektrophotometrische Bestimmung von Palladium nach Mitfällung seines 9,10-Phenanthrenchinonmonoximates auf mikrokristallines Naphthalin

Zusammenfassung Ein spektrophotometrisches Verfahren zur Mikrobestimmung von Pd(II) als 9,10-Phenanthrenchinonmonoximat durch Mitfällung auf festes Naphthalin und Lösung in Chloroform wurde ausgearbeitet. Dieses Verfahren eignet sich zur Bestimmung von Palladium in gewissen synthetischen Gemischen.

     

Anionic-nonionic surfactant interaction by nuclear magnetic resonance

Summary The interaction between anionic (sodium dodecyl benzene sulfonate) surfactant and nonionic (Tri and Tetra propylene glycol monomethyl ether) surfactant was studied using nuclear magnetic resonance measurement. It was observed that the addition of sodium dodecyl benzene sulfonate to the solution of nonionic surfactant (Tri and Tetra propylene glycol mono methyl ether) caused an upfield shift of the central protons of the nonionic surfactants. The aromatic protons of sodium-dodecyl benzene sulfonate undergo a very small, almost negligible, downfield shift. The changes in the chemical shift values and the integration values of the polypropylene protons and benzene protons was interpreted in terms of mixed micelle formation with the simultaneous presence of highly fluid mixed micelles of varying compositions.With 2 figures and 2 tables