Mechanism study of the Mn‐substituted magnesium borate: decreased sintering temperature and improved dielectric property

Author(s):  
Rui Peng ◽  
Yongcheng Lu ◽  
Yuanxun Li ◽  
Hua Su ◽  
Liang Shi ◽  
...  
2017 ◽  
Vol 883 ◽  
pp. 3-6
Author(s):  
Sadia Tasnim Mowri ◽  
Quazi Delowar Hossain ◽  
M.A. Gafur ◽  
Aninda Nafis Ahmed ◽  
Muhammad Shahriar Bashar

(Bi2O3Fe2O3)0.8(Nb2O5)0.2 was synthesized by solid state reaction method. (Bi2O3Fe2O3)0.8(Nb2O5)0.2 was made for the investigation of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Dielectric property. XRD pattern reveals that three phases were obtained with Bismuth Iron Niobium Oxide. SEM elicits that grain size increases with the enhancement of sintering temperature. Dielectric property decreases with the augmentation of frequency.


2012 ◽  
Vol 512-515 ◽  
pp. 1155-1159 ◽  
Author(s):  
Xin Ye Yang ◽  
Xiao Hui Wang ◽  
An Ji ◽  
Long Tu Li

Both BaTi4O9 and Ba2Ti9O20 have the best microwave properties among many compounds in BaO-TiO2 system. The microwave performance of the ceramics in BaO-TiO2 system, which were prepared by conventional solid state method, was investigated in this paper. The study indicates that the (Ti,Zr)/Ba ratio has a great effect on the dielectric properties of the ceramic due to different BaTi4O9/Ba2Ti9O20 ratio. The pure BaTi4O9 ceramic exhibits the most outstanding microwave properties, with εr=35.55 and Q×f=43300GHz. On the contrary, the dielectric property of the pure Ba2Ti9O20 ceramic was not good enough, which should be doped with some additive additions. WO3 was incorporated into the system and the sintering temperature was adjusted to improve the microwave dielectric property. The Q×f was increased to 38000GHz by adding 1.35mol% WO3 due to the formation of a little BaWO4 phase. When sintered at a higher temperature (1380°C), the BaO-TiO2 system ceramic has εr =37.04 and Q×f =44874GHz.


Author(s):  
Gareth Thomas

Silicon nitride and silicon nitride based-ceramics are now well known for their potential as hightemperature structural materials, e.g. in engines. However, as is the case for many ceramics, in order to produce a dense product, sintering additives are utilized which allow liquid-phase sintering to occur; but upon cooling from the sintering temperature residual intergranular phases are formed which can be deleterious to high-temperature strength and oxidation resistance, especially if these phases are nonviscous glasses. Many oxide sintering additives have been utilized in processing attempts world-wide to produce dense creep resistant components using Si3N4 but the problem of controlling intergranular phases requires an understanding of the glass forming and subsequent glass-crystalline transformations that can occur at the grain boundaries.


2013 ◽  
Vol 67 (9) ◽  
pp. 991-994
Author(s):  
Shinichi Kitagawa

2019 ◽  
Author(s):  
Huaimin Wang ◽  
Zhaoqianqi Feng ◽  
Weiyi Tan ◽  
Bing Xu

<p>Selectively targeting cell nucleolus remains a challenge. Here we report the first case that D-peptides form membraneless molecular condensates with RNA for targeting cell nucleolus. A D-peptide derivative, enriched with lysine and hydrophobic residues, self-assembles to form nanoparticles, which enter cells through clathrin dependent endocytosis and mainly accumulate at cell nucleolus. Structural analogue of the D-peptide reveals that particle morphology of the assemblies, which depends on the side chain modification, favors the cellular uptake. Contrasting to those of the D-peptide, the assemblies of the corresponding L-enantiomer largely localize in cell lysosomes. Preliminary mechanism study suggests that the D-peptide nanoparticles interact with RNA to form membraneless condensates in the nucleolus, which further induces DNA damage and results in cell death. This work illustrates a new strategy for rationally designing supramolecular assemblies of D-peptides for targeting subcellular organelles.</p>


Author(s):  
Ashutosh Mohanty ◽  
Diptikanta Swain ◽  
Sharada Govinda ◽  
Tayur N. Guru Row ◽  
D. D. Sarma

2018 ◽  
Vol 31 (3) ◽  
pp. 26 ◽  
Author(s):  
Laheeb. A. Mohammed ◽  
Kareem. A. Jasim

   on this research is to study the effect of nickel oxide substitution on the pure phases superconductor Tl0.5Pb0.5Ba2Can-1Cun-xNixO2n+3-δ (n=3) where x=(0,0.2,0.4,0.6,0.8.and 1.0). The specimens in this work were prepared with used  procedure of solid state reaction with sintering temperature 8500C for 24 h .we used technical (4-prob)to calculated and the critical temperature Tc . The results of the XRD diffraction analysis showed that the structure for pure and doped phases was tetragonal with phases high-Tc phase (1223),(1212) and low-Tc phase (1202)  and add to the presence of some impure phase. It was noted the value a=b,c  the parameter of  the lattice increment  with the increment of Ni content. The increment of (NiO) concentration effects electrical resistivity, dielectric constant and the hardness.


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