No. Due to their apparently extreme optical to X-ray properties, Narrow Line Seyfert 1s (NLSy1s) have been considered a special class of active galactic nuclei (AGN). Here, we summarize observational results from different groups to conclude that none of the characteristics that are typically used to define the NLSy1s as a distinct group – from the, nowadays called, Broad Line Seyfert 1s (BLSy1s) – is unique, nor ubiquitous of these particular sources, but shared by the whole Type 1 AGN. Historically, the NLSy1s have been distinguished from the BLSy1s by the narrow width of the broad Hb emission line. The upper limit on the full width at half maximum of this line is 2000kms−1 for NLSy1s, while in BLSy1s it can be of several thousands

The Bi2Se3 compound was synthesis by fusing initial compounds consisting of
extra pure elements in stoichiometric ratio from elements compound, charged inside
quartz ampoule. The crystal growth of Bi2Se3 carried out using Brighaman technique
process from melting f (Bi+Se ) at temperature of 810 ºC for about 48 hrs. Single crystal
of Bi2Se3 has been grown in direction (211) after slow cooling on account of heat
gradient to zone furnaces at cooling rate (1-3) C/hr. The structure study of the compound
was determined by x-ray diffraction technique, which it has bismuthinite structure and
orthorhombic unit cell with lattice parameters of a=10.2678 Å, b=11.2392 Å and
c=5.1737 Å

Silver sulfide and the thin films Ag2Se0.8Te0.2 and Ag2Se0.8S0.2 created by the thermal evaporation process on glass with a thickness of 350 nm were examined for their structural and optical properties. These films were made at a temperature of 300 K. According to the X-ray diffraction investigation, the films are polycrystalline and have an initial orthorhombic phase. Using X-ray diffraction research, the crystallization orientations of Ag2Se and Ag2Se0.8Te0.2 & Ag2Se0.8S0.2 (23.304, 49.91) were discovered (XRD). As (Ag2Se and Ag2Se0.8Te0.2 & Ag2Se0.8S0.2) absorption coefficient fell from (470-774) nm, the optical band gap increased (2.15 & 2 & 2.25eV). For instance, the characteristics of thin films made of Ag2Se0.8Te0.2 and Ag2Se0.8S0.2

Dam and powerhouse operation sustainability is a major concern from the hydraulic engineering perspective. Powerhouse operation is one of the main sources of vibrations in the dam structure and hydropower plant; thus, the evaluation of turbine performance at different water pressures is important for determining the sustainability of the dam body. Draft tube turbines run under high pressure and suffer from connection problems, such as vibrations and pressure fluctuation. Reducing the pressure fluctuation and minimizing the principal stress caused by undesired components of water in the draft tube turbine are ongoing problems that must be resolved. Here, we conducted a comprehensive review of studies performed on dams, powerhouses, a

Coherent density fluctuation model (CDFM) has been used to calculate the
proton momentum distributions (PMD) and elastic electron scattering form factors,
F(q), of the ground state for some even mass nuclei of fp-shell, such as 52Cr, 58Fe and
64Ni nuclei. Both of the PMD and F(q) have been expressed in terms of the weight
function ( ( ) )
2
f x which is determined by means of the charge density
distributions (CDD) of the nuclei and determined from theory and experiment. The
feature of the long-tail behavior at high momentum region of the PMD’s has been
obtained by both the theoretical and experimental weight functions. The calculated
form factors of these nuclei are in reasonable agreement with those of th

In this paper, inelastic longitudinal electron scattering form factors C2 and C4
transitions have been studied in Ti 48,50
and Cr 52,54
nuclei with the aid of shell
model calculations. The core polarization transition density was evaluated by
adopting the shape of Tassie model togther with the derived form of the ground state
two-body charge density distributions (2BCDD's). The following transitions have
been investigated; 0 2 2 2 1 1
   and 0 2 4 2 1 1
   of Ti 48 , 0 3 2 3 1 1
   and
0 3 4 3 1 1
   of Ti 50 , 0 2 2 2 1 1
   and 0 2 4 2 1 1
   of Cr 52 and
0 3 2 3 1 1
   and 0 3 4 3 1 1
   of Cr 54 nuclei. It is fou

The main purpose of this paper, is to introduce a topological space , which is induced by reflexive graph and tolerance graph , such that  may be infinite. Furthermore, we offered some properties of  such as connectedness, compactness, Lindelöf and separate properties. We also study the concept of approximation spaces and get the sufficient and necessary condition that topological space is approximation spaces.