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931.
Mohsen Rostamizadeh Malek Taher Maghsoodlou Sayyed Mostafa Habibi‐Khorassani Nourallah Hazeri Faramarz Rostami Charati Mohammad Amin Kazemian Brian W. Skelton Mohamed Makha 《Heteroatom Chemistry》2011,22(6):715-722
The reaction between dialkyl acetylenedicarboxylates and NH heterocyclic compounds in the presence of triethyl phosphite leads to stable phosphorus ylide derivatives in good yields. The X‐ray crystallographic data and theoretical study show that there is a resonance between two bonds of C19P1 and C191O191 in phosphorus ylide 4d . This compound crystallizes in the orthorhombic system, space group (Pca21), with unit cell parameters a = 17.3699(3) Å, b = 13.5500(2) Å, c = 18.4627(3) Å, α = 90°, β = 90°, γ = 90°, Z = 8, and V = 4345.4(12) Å3. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:715–722, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20739 相似文献
932.
Let K(a (p); λ, μ) be a graph with p parts, each part having size a, in which the multiplicity of each pair of vertices in the same part (in different parts) is λ (μ, respectively). In this paper we consider the following embedding problem: When can a graph decomposition of K(a (p); λ, μ) be extended to a Hamiltonian decomposition of K(a (p+r); λ, μ) for r > 0? A general result is proved, which is then used to solve the embedding problem for all ${r \geq \frac{\lambda}{\mu a}+ \frac{p-1}{a-1}}$ . The problem is also solved when r is as small as possible in two different senses, namely when r = 1 and when ${r = \frac{\lambda}{\mu a} - p+1}$ . 相似文献
933.
In this paper, we investigate the topologically weak concepts of topological groupoids by giving the concepts of α-topological groupoid and α-topological subgroupoid. Furthermore, we show the role of the density condition to allow α-topological subgroupoid inherited properties from α-topological groupoid and the irresoluteness property for the structure maps in α-topological groupoid is studied. We also give some results about the fibers of α-topological groupoids. 相似文献
934.
Wang Zhen Mazhar Hussain Muhammad Kamran Siddiqui Sana Javed Sadia Khalid Naima Amin 《International journal of quantum chemistry》2024,124(1):e27295
This study delves into a comprehensive physical analysis of entropy measures applied to sodium oxide . A key idea in information theory and thermodynamics, entropy is essential to comprehending the stability of a system. The study clarifies the intricate relationships and physical properties of by combining theoretical analysis with statistical methods, providing important knowledge for material design and industrial operations. In a chemical graph, atoms are shown by vertices while their bonding are illustrated by edges. Sodium oxide is a major contributor to manufacture glass, it also has potential applications in sequestration, transparent materials, biomedical devices and nano grating glass. A topological index is a relationship between the molecular graph and its topology. We have computed various graph entropies based on different topological indices of chemical graph of sodium oxide. Further we have integrated these graph entropies with distinct thermodynamical measures of sodium oxide by developing mathematical models between both quantities. We have developed these mathematical frameworks in MATLAB. All the models are selected relying on the least mean squared error or sum of squared error. 相似文献
935.
Design of a Simple Integrated Coupler for SPP Excitation in a Dielectric Coated Ag Thin Film 下载免费PDF全文
A simple integrated coupler is proposed for the efficient excitation of surface plasmon polariton (SPP) mode in a thin metal film. The SPP mode is generated in a single Ag-dielectric interface by the incident field and coupled with an Ag thin film. The coupling efficiency at different wavelengths using two different dielectrics, gallium lanthanum sulfide (GLS) and aluminum gallium arsenide (AIGaAs) is calculated by analyzing the SPP propagation dynamics with the finite difference time domain method. A maximum coupling efficiency of 70~ is obtained at a wavelength of 46Ohm when GLS is used, whereas the corresponding value obtained for A1GaAs is 60~o at 56Onto. The proposed structure can be used to excite SPPs in a nano-thin film from an external bulky source and is easier to fabricate since a single interface metal-dielectric configuration is used to excite the metal-thin film. 相似文献
936.
Amin AS Mohammed TY Mousa AA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(11):2577-2584
Yttrium reacts with 5-(4'-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (I), 5-(2'-bromophenylazo)-6-hydroxypyrimidine-2,4-dione (II), 5-(2',4'-dimethylphenylazo)-6-hydroxypyrimidine-2,4-dione (III), 5-(4'-nitro-2',6'-dichlorophenylazo)-6-hydroxypyrimidine-2,4-dione (IV), 5-(2'-methyl-4'-hydroxyphenylazo)-6-hydroxypyrimidine-2,4-dione (V) to form a dark pink complexes, having an absorption maximum at 610, 577, 596, 567 and 585 nm, respectively. The complex formation was completed spontaneously in theil buffer solution and the resulting complex was stable for at least 3 h after dilution. Under the optimum conditions employed, the molar absorptivities were found to be 1.60 x 10(4), 1.29 x 10(4), 1.96 x 10(4), 1.45 x 10(4) and 1.21 x 10(4) l mol(-1) cm(-1) and the molar ratios were (1:1) and (1:2) (M:L). The linear ranges were found within 95 microg of yttrium in 25 ml solution. One of the characteristics of the complex was its high tolerance for calcium and hence a method of separation and enrichment of microamounts of yttrium by using calcium oxalate precipitate was developed and applied to measure yttrium in nickel-base alloys. Interfering species and their elimination have been studied. The precision and recovery are both satisfactory. 相似文献
937.
Mohd Asyadi Azam Nor Syafira Abdul Manaf Elyas Talib Mohd Shahril Amin Bistamam 《Ionics》2013,19(11):1455-1476
Carbon nanomaterial especially carbon nanotube (CNT) possesses remarkably significant achievements towards the development of sustainable energy storage applications. This article reviews aligned CNTs grown from chemical vapor deposition (CVD) technique as electrode material in batteries and electrochemical capacitors. As compared to the entangled CNTs, aligned or well-organized CNTs have advantages in specific surface area and ion accessibility in which more electrolyte ions can access to CNT surfaces for better charge storage performance. CVD known as the most popular technique to produce CNTs enables the use of various substrates and CNT can grow in a variety of forms, such as powder, films, aligned or entangled. Also, CVD is a simple and economic technique, and has good controllability of direction and CNT dimension. High purity of as-grown CNTs is also another beauty of the CVD technique. The current trend and performance of devices utilizing CNTs as electrode material is also extensively discussed. 相似文献
938.
Yasir Jamil Humaima Saeed M. Raza Ahmad Shakeel Ahmad Khan Hashim Farooq Muhammad Shahid K. M. Zia Nasir Amin 《Applied Physics A: Materials Science & Processing》2013,110(1):207-210
Laser ablation propulsion is a form of beam-powered propulsion in which a pulsed laser ablates a target material thus producing thrust. We report in this work the measurements of various parameters related to laser-induced micropropulsion in toluene diisocyanate-based polyurethane polymer, aluminum and Co–Ni ferrite. The targets were irradiated by a Q-switched pulsed Nd–YAG laser at 1064 nm (pulse duration 5 ns) under atmospheric conditions. A contact-free optical triangulation method was used to measure the laser ablation induced thrust in the samples. The measurements and calculations depict that Co–Ni ferrite is better in terms of critical propulsion parameters C m and I sp. It has been observed that the propulsion parameters depend on the energy per pulse of the incident laser beam. 相似文献
939.
Alaa S. Amin 《光谱学快报》2013,46(6):1003-1011
Abstract A new modified Spectrophotometric procedures are presented for the determination of three pharmaceutical antibiotic compounds through charge-transfere complexation reaction with chloranil. The complex shows an absorption mAxima at 550 nm, having a molar absorptivity coefficient of 5.55×103,7.81×103 and 1.38×104 1. mol?1cm?1 for ampicillin, amoxycillin and neomycin, respectively. Optimization of the reaction conditions has been investigated Obediance to Beer's law (40μg/ml) permitted the assay of thes drugs in its dosage forms A variety of pharmaceutical dosage forms containing ampicillin, amoxycillin and neomycin are successfully analysed by the proposed procedure. 相似文献
940.
This Letter is a study of the effects of higher dimensional gravity and Brans–Dicke (BD) scalar field on cosmic acceleration in 5-D BD cosmological model. We assume a flat cosmological model in which the matter content of the universe is either cold dark matter or radiation. In a framework to study attractor solutions in the phase space we simultaneously constrain the model parameters with the observational data for distance modulus. The phase space analysis illustrates that the universe begins from an unstable state in the past and eventually reaches an asymptotically stable state (attractor). We examine the model by performing Hubble parameter test in addition to statefinder diagnosis. We also reconstruct the equation of state parameter, the scale factor in 3-D space and along extra dimension. The results show that due to the presence of extra dimension and Brans–Dicke scalar field in the model, the universe undergoes a period of acceleration. 相似文献