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81.
Inspired by the work of D.G.Kelly and S.Sherman on general Griffiths inequalities on correlations in Ising ferromagnets, we
formulate and prove Griffith–Kelly–Sherman-type inequalities for the ferromagnetic Potts model with a general number q of local states. We take as local state space for the q-state Potts model the set F
c
= { − l, − l + 1, ⋯ ,l − 1,l},where
l=\fracq-12l=\frac{q-1}{2}. The important properties of F
c
for what follows are that |F
c
| = q and F
c
= − F
c
. 相似文献
82.
In this article, a passive neurowavelet based on islanding detection technique for grid‐connected inverter‐based distributed generation has been developed. Connecting distributed generator to the distribution network has many benefits such as increasing the capacity of the grid and enhancing the power quality. However, it gives rise to many problems. This is mainly due to the fact that distribution networks are designed without any generation units at that level. Hence, integrating distributed generators into the existing distribution network is not problem‐free. Unintentional islanding is one of the encountered problems. Islanding is the situation where the distribution system containing both distributed generator and loads is separated from the main grid as a result of many reasons such as electrical faults and their subsequent switching incidents, equipment failures, or preplanned switching events like maintenance. The proposed method utilizes and combines wavelet analysis and artificial neural network to detect islanding. Discrete wavelet transform is capable of decomposing the signals into different frequency bands. It can be utilized in extracting discriminative features from the acquired voltage signals. Passive schemes have a large nondetection zone (NDZ) and concern has been raised on active method due to its degrading power quality effect. The main emphasis of the proposed scheme is to reduce the NDZ to as close as possible and to keep the output power quality unchanged. The simulations results, performed by MATLAB/Simulink, shows that the proposed method has a small NDZ. Also, this method is capable of detecting islanding accurately within the minimum standard time. © 2014 Wiley Periodicals, Inc. Complexity 21: 309–324, 2015 相似文献
83.
Sanagi MM Nasir Z Ling SL Hermawan D Ibrahim WA Naim AA 《Journal of AOAC International》2010,93(4):1322-1330
Linearity assessment as required in method validation has always been subject to different interpretations and definitions by various guidelines and protocols. However, there are very limited applicable implementation procedures that can be followed by a laboratory chemist in assessing linearity. Thus, this work proposes a simple method for linearity assessment in method validation by a regression analysis that covers experimental design, estimation of the parameters, outlier treatment, and evaluation of the assumptions according to the International Union of Pure and Applied Chemistry guidelines. The suitability of this procedure was demonstrated by its application to an in-house validation for the determination of plasticizers in plastic food packaging by GC. 相似文献
84.
Ahmad VU Zubair M Abbasi MA Kousar F Rashid MA Rasool N Tareen RB 《Natural product research》2006,20(1):69-74
Phytochemical investigation of Platytaenia multicaule resulted in the isolation of two new ceramides, N-triacontylpentadecanamide and 1,3,4-trihydroxy-2,dodecanoylamino-(24E)-unacotenene, along with two known compounds, beta-sitosterol and beta-sitosterol glycoside. The structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR analyses, including COSY, NOESY, HMQC, and HMBC correlations. 相似文献
85.
Mohd Nasir M. N. Al-Mansoori M. H. Abdul Rashid H. A. Choudhury P. K. Yusoff Z. 《Laser Physics》2008,18(4):446-448
In this paper, we demonstrate a multiwavelength Brillouin erbium fiber laser in a Fabry-Perot cavity. The design utilized a bidirectional oscillation provided by a fiber Bragg grating filter and a fiber loop mirror at each end of the laser cavity. A stable operation of 25 Brillouin-Stokes lines was obtained at around a 1559-nm band. 相似文献
86.
Chaitanya A. K. Koppisetty Waqas Nasir Francesco Strino Gustaf E. Rydell Göran Larson Per-Georg Nyholm 《Journal of computer-aided molecular design》2010,24(5):423-431
Norovirus strains are known to cause recurring epidemics of winter vomiting disease. The crystal structure of the capsid protein
of VA387, a representative of the clinically important GII.4 genocluster, was recently solved in complex with histo-blood
group A- and B-trisaccharides. However, the VA387 strain is known to bind also to other natural carbohydrates for which detailed
structural information of the complexes is not available. In this study we have computationally explored the fit of the VA387
with a set of naturally occurring carbohydrate ligands containing a terminal α1,2-linked fucose. MD simulations both with
explicit and implicit solvent models indicate that type 1 and 3 extensions of the ABO-determinant including ALeb and BLeb pentasaccharides can be well accommodated in the site. Scoring with Glide XP indicates that the downstream extensions of
the ABO-determinants give an increase in binding strength, although the α1,2-linked fucose is the single strongest interacting
residue. An error was discovered in the geometry of the GalNAc-Gal moiety of the published crystal structure of the A-trisaccharide/VA387
complex. The present modeling of the complexes with histo-blood group A-active structures shows some contacts which provide
insight into mutational data, explaining the involvement of I389 and Q331. Our results can be applicable in structure-based
design of adhesion inhibitors of noroviruses. 相似文献
87.
88.
Warda Rahim Jonathan M. Skelton Christopher N. Savory Ivana R. Evans John S. O. Evans Aron Walsh David O. Scanlon 《Chemical science》2020,11(30):7904
Accurately modelling polymorphism in crystalline solids remains a key challenge in computational chemistry. In this work, we apply a theoretically-rigorous phonon mode-mapping approach to understand the polymorphism in the ternary metal oxide Bi2Sn2O7. Starting from the high-temperature cubic pyrochlore aristotype, we systematically explore the structural potential-energy surface and recover the two known low-temperature phases alongside three new metastable phases, together with the transition pathways connecting them. This first-principles lattice-dynamics method is completely general and provides a practical means to identify and characterise the stable polymorphs and phase transitions in materials with complex crystal structures.Using a phonon mode-mapping approach, we recover the known experimental phases of the ternary oxide Bi2Sn2O7 and identify three new metastable phases, highlighting the utility of the method for polymorph prediction on many other complex materials. 相似文献
89.
A new and convenient spectrophotometric method for the estimation of vanadium(IV) with NTA is described. The minimum ratio of metal ion to ligand, working pH, wavelength for maximum absorbance of the complex ion, and the effect of various cations and anions are described. The complex ion obeys Beer's law in the concentration range 1–32 mmol/liter of the vanadium(IV) ion. It is observed that iron(II), cobalt(II), nickel(II), copper(II), and oxidizing anions such as chromate and nitrite interfere in this determination, whereas managanese(II), chromium(III), iron(III), and anions like nitrate, chloride, bromide, iodide, thiocyanate, sulfate, and sulfite do not have any effect. Excessive amounts of acetate, phosphate, oxalate, tartrate and thiosulfate must also be avoided in this determination. Anions and cations which interfere in the determination of vanadium(IV) by NTA should not be present in the system. 相似文献
90.