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91.
A. El-Toukhy A. F. M. Hefny L. El Sayed M. F. Iskander 《Monatshefte für Chemie / Chemical Monthly》1982,113(2):171-180
The reaction of bis(N-salicylidene)dicarboxylic acid dihydrazides (H4
Lig) with cobalt(II) salts was investigated. Chelates of the types Co(H3
Lig)X ·nH2O, Co2(H2
Lig)X
2, Co3(H3
Lig)2
X
4, Co(H2
Lig) ·nH2O and Co(H3
Lig)2 ·nH2O (X=Cl, Br, I or SCN) were isolated and characterized by their infrared and electronic spectra as well as their magnetic properties.
Koordinationsverbindungen von Hydrazinderivaten mit Übergangsmetallen, 23. Mitt.: Kobalt(II)-Chelate von Bis(N-salicyliden)dicarbonsäuredihydraziden
Zusammenfassung Die Reaktion von Bis(N-salicyliden)dicarbonsäuredihydraziden (H4 Lig) mit Kobalt(II)-Salzen ergab Chelate vom Typ Co(H3 Lig)X ·nH2O, Co2(H2 Lig)X 2, Co3(H3 Lig)2 X 4, Co(H2 Lig) ·nH2O and Co(H3 Lig)2 ·nH2O (X=Cl, Br, I oder SCN). Die Charakterisierung erfolgte mittels IR, Elektronenspektren und magnetischer Eigenschaften.相似文献
92.
Yang Zhong-zhi Branka Kova
Edgar Heilbronner Sayed Eltamany Henning Hopf 《Helvetica chimica acta》1981,64(7):1991-2001
The photoelectron (PE.) spectra of thirteen methyl-substituted [2.2]paracyclophanes have been recorded and analyzed, to assess the influence of methyl-substitution on their ionization energies. It is shown that this influence is qualitatively and quantitatively the same as for benzenes and other π-systems. Comparison with the previous results obtained for the [2r]cyclophanes (r=2 to 6) strongly suggests that the hyperconjugative model for alkyl-group/π-system interactions is more appropriate than the inductive one. 相似文献
93.
The acoustic environment of courtyard housing has been studied and the ability of the courtyard to attenuate external noise examined. A scale-model was used to study the effect of the ground treatment, the source and the receiver locations, the depth of the courtyard and the position and arrangement of openings in the walls.Experimental results obtained from the model, together with a simple procedure for predicting the sound pressure levels inside the courtyard, are presented. 相似文献
94.
Ali Ali Arafa Ibrahim Sayed Shafie Fathi Sultan Ahmed Sultan 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1956,7(3):256-264
The thermoelectric power of natural specimens of lead sulphide crystals has been measured between room temperature and 700° K. Specimens which are of then-type remain as such throughout the temperature range. Thep-type specimens, however, show an initial small rise followed by a gradual decrease and a subsequent change of sign ata temperature which, in some specimens, is well defined. Further increase of temperature results in a negative extremum. From this stage onwards there seems to develop a common behaviour for both types of specimens. Some crystals which were initially of thep-type changed over to then-type and remained as such throughout subsequent investigation. Among the crystals one showed a metallic conduction and an extraordinary large thermoelectric power. 相似文献
95.
A perturbed hard-sphere equation of state (EOS) has been previously employed to predict pressure–volume–temperature properties
of some ionic liquids (ILs) with phosphonium-, pyridinium-, and pyrrolidinium cations. In this work, we have extended the
considered EOS to another class of ILs in compressed states. This class consists of 14 imidazolium-based ILs. The predicted
densities were compared with those obtained from the experiment, over a broad pressure range from 0.1 to 200 MPa. From 1,122
data points examined for the aforementioned ILs, the total average absolute deviation was found to be 1.05%. 相似文献
96.
The optical properties of ethylene vinyl acetate (EVA) film have been studied. The effects of gamma irradiations on the optical spectrum of EVA films have been investigated using spectrophotometric measurements of reflectance and transmittance in the wavelength range 200–1100 nm. The absorption spectra were recorded in the UV–vis region for the unirradiated and irradiated films (from 0 to 50 kGy). Optical constants such as refractive index (n), extinction coefficient (K), and complex dielectric constant have been determined, as well as the optical dispersion parameters and high frequency dielectric constants. A large dependence of the fundamental optical constants on the irradiation dose was noticed. On irradiation, a higher refractive index was obtained as compared with that for unirradiated film. The dispersion parameters, such as E 0 (single‐oscillator energy), E d (dispersive energy), and M ?1 and M ?3 (moments), are discussed in terms of the single‐oscillator Wemple–DiDomenico model. 相似文献
97.
A new transparent bulk glass from the system 76TeO2?·?10ZnO?·?9.0PbO?·?1.0PbF2?·?3.0Na2O doped with Er3+ (TZPPN doped with Er3+) has been prepared using the conventional melt-quenching method. Results of differential thermal analysis (DTA) measurements indicate good thermal stability of this glass. The refractive indices at different wavelengths, the optical energy gap, the Sellmeier gap energy and the dispersion energy have been estimated. The Judd–Ofelt parameters, Ω t (t?=?2,?4,?6) of Er3+ were evaluated from optical absorption spectra. Electric dipole, magnetic dipole type transition probabilities, spectroscopic quality factors, branching ratio and radiative lifetimes of several excited states of Er3+ have been predicted using intensity Judd–Ofelt parameters. The spectroscopic properties indicate that TZPPN glass doped with Er3+ is a promising candidate for laser applications and may be suitable for upconversion fibre optical devices. 相似文献
98.
Javid Jouzdani Seyed Jafar Sadjadi Mohammad Fathian 《Applied Mathematical Modelling》2013,37(18-19):8467-8483
In this paper, dynamic dairy facility location and supply chain planning are studied through minimizing the costs of facility location, traffic congestion and transportation of raw/processed milk and dairy products under demand uncertainty. The proposed model dynamically incorporates possible changes in transportation network, facility investment costs, monetary value of time and changes in production process. In addition, the time variation and the demand uncertainty for dairy products in each period of the planning horizon is taken into account to determine the optimal facility location and the optimal production volumes. Computational results are presented for the model on a number of test problems. Also, an empirical case study is conducted in order to investigate the dynamic effects of traffic congestion and demand uncertainty on facility location design and total system costs. 相似文献
99.
The synthesis of a new series of annulated thieno[2,3‐b]pyridines was performed. Ester compound 1 underwent heterocyclization upon reaction with phenylisothiocyanate and formamide to afford pyrimidines 2 and 3 , respectively. Thienopyrimidine 5 was resulted via reaction of amino derivative 1 with triethyl orthoformate to afford the non‐isolable intermediate 4 , which allowed hydrazinolysis with hydrazine hydrate to afford the target compound. Pyrimidine type 5 was condensed with p‐nitrobenzaldehyde to afford Schiff base 6 . Refluxing of ester 1 with ethyl cyanoacetate and diethyl malonate followed by base‐mediated heterocyclization afforded condensed pyridines 8 and 9 , respectively. The tetracyclic pyrazine derivative 14 was obtained from the reaction of amino compound 1 with 2,5‐dimethoxytetrahydrofuran followed by hydrazinolysis to give carbohydrazide 11 , which undergo diazotization followed by Curtius rearrangement. The antibacterial results illustrated no significant results for the investigated compounds except compound 5 , which has moderate activity against Gram‐positive bacteria. 相似文献
100.
Mohamed G. Assy Hassan A. El‐Sayed Nabil H. Ouf Ahmed Hamza Hesham A. Morsy 《Journal of heterocyclic chemistry》2019,56(10):2954-2959
A simple and direct synthetic methodology for a novel series of azines and their annulated systems was performed. Heterocyclization of acyl isothiocyanate 2 with urea or malononitrile gave s‐triazine 4 and 1,3‐oxazine 7 derivatives, respectively. The reaction of heteroallene 1 with acetylacetone tolerated 2‐thioxopyridine derivative 9 . The latter compound underwent heterocyclization with urea, hydrazine hydrate, or phenyl hydrazine to give the annulated pyridines 10 – 12 . Pyrimidinethione 14 was resulted from reaction of acylisothiocyanate with enamine 13 . Condensation of compound 14 with hydrazine hydrate, phenyl hydrazine, urea, and 3‐nitrobenzaldehyde in the presence of ethyl cyanoacetate or sodium hydroxide afforded 15 – 20 , respectively. 相似文献