Novel heterocyclic polyimide 5(a,b) have been synthesized based on polyacrylic backbone. The synthetic route start with nucleophilic substitution of 2-amino, or 4-amino, pyridine 1(a,b) to the polyacryloyl chloride afforded poly substituted amide 2(a,b). Another nucleophilic substitution were carried with adipoyl chloride to form polyimide chloride 3(a,b). Treatment of 3(a,b) with hydrazine hydrate afforded acid hydrazide polyimide 4(a,b), which upon cyclocondensation with carbon disulfide gave the target heterocyclic polyimide. The synthesized compounds were identified by spectroscopic methods: FT-IR, 1H-NMR and 13C-NMR.
The aim of this paper, study the effect of carbon nanotubes on the electrical properties of polyvinylchloride. Samples of polyvinylchloride carbon nanotubes composite prepared by using hot press technique. The weight percentages of carbon nanotubes are 0,5,10 and 20wt.%. Results showed that the D.C electrical conductivity increases with increasing of the weight percentages of carbon nanotubes. Also, the D.C electrical conductivity changed with increase temperature for different concentrations of carbon nanotubes. The activation energy of D.C electrical conductivity is decreased with increasing of carbon nanotubes concentration.
In this paper the research introduces a new definition of a fuzzy normed space then the related concepts such as fuzzy continuous, convergence of sequence of fuzzy points and Cauchy sequence of fuzzy points are discussed in details.
The purpose of this paper is to give some results theorems , propositions and corollaries concerning new algebraic systems flower , garden and farm with accustomed algebraic systems groupoid , group and ring.
A number of ehemical ion materials were used as an absorber against solar energy. These materials were selected according to their absorption spectra in the wavelength range 300-800nm where the solar spectrum is coventrated. A solar olleetorw^esigd and The ability of each material inside the collector for absorbing the solar radiation was examined by a converter parameter “R”.According to the “R” parameter, the cohaltous and copperic ions material seems to be of higher capability for absorbing solar energy than the other materials.All the results were analyzed by means of a least-squared fitting program.
Chaotic systems have been proved to be useful and effective for cryptography. Through this work, a new Feistel cipher depend upon chaos systems and Feistel network structure with dynamic secret key size according to the message size have been proposed. Compared with the classical traditional ciphers like Feistel-based structure ciphers, Data Encryption Standards (DES), is the common example of Feistel-based ciphers, the process of confusion and diffusion, will contains the dynamical permutation choice boxes, dynamical substitution choice boxes, which will be generated once and hence, considered static,
While using chaotic maps, in the suggested system, called
Topology and its applications occupy the interest of many researching centers in the advanced world. From this point of view and because the near open sets play a very important role in general topology and they are now the research topics of many topologists worldwide and its sets doesn’t enter in fibrewise topology yet. Therefore, we use some of the near open sets to be model for introduce results and new spaces in fibrewise topological spaces. Also, there is a very important role of closure operators in constructing a topological spaces, so we introduce a new closure operators on the power set of vertices on graphs and conclusion theorems and new spaces from it. Furthermore, we discuss the relationships of connectedness between some ty
... Show MoreHiding secret information in the image is a challenging and painstaking task in computer security and steganography system. Certainly, the absolute intricacy of attacks to security system makes it more attractive.in this research on steganography system involving information hiding,Huffman codding used to compress the secret code before embedding which provide high capacity and some security. Fibonacci decomposition used to represent the pixels in the cover image, which increase the robustness of the system. One byte used for mapping all the pixels properties. This makes the PSNR of the system higher due to random distribution of embedded bits. Finally, three kinds of evaluation are applied such as PSNR, chi-square attack, a
... Show MoreNew data on jumping spiders (Salticidae) and tangle-web spiders (Theridiidae) of Armenia are provided on the basis of recently collected specimens in various regions of Armenia. One species, Ballus rufipes (Simon, 1868) is recorded as new to the Caucasus Region, in addition to the following species: Neon reticulatus (Blackwall, 1853), Pellenes brevis (Simon, 1868), Salticus scenicus (Clerck, 1757) and Synageles dalmaticus (Keyserling, 1863) that belong to a family Salticidae, are recorded in Armenia for the first time.
A further 7 species of Theridiidae are recorded in Armenia for the first time Kochiura aulica (C. L. Koch, 1838), Steatoda albomaculata (De Geer, 1778), Steatoda bipunctata (Linnaeus, 1758), Steatoda castanea Clerk, 175