scholarly journals Influence of the method for producing radiotransparent ceramics based on the system SrO—BaO—Al2O3—SiO2 on its properties

2017 ◽  
Vol 117 ◽  
pp. 167-175
Author(s):  
E. V. Chefranov ◽  
E. Yu. Fedorenko ◽  
R. V. Krivobok ◽  
G. V. Lisachuk ◽  
I. A. Gusarova

The results of the study of samples of radiotransparent ceramics based on the system SrO—BaO—Al2O3—SiO2 which have been made in one-step and two-step process have been presented. A comparative analysis of their sintering characteristics and dielectric properties have shown that materials which were obtained by a two-stage process are characterized by a relatively high degree of sintering (W = 2..72 ÷ 3.97 %, Papp = 2901 ÷ 3180 kg/m3), sufficient values of dielectric losses tangent (tgδ = 0.000258 ÷ 0.000313), however, their dielectric permittivity (ε = 12.11 ÷ 14.38) don’t reach the specified level. It was concluded that it is necessary to modify the compositions of the basic oxide system using small additives that intensify sintering and provide high-temperature stability of solid solutions of slawsonite and celsian.

2020 ◽  
Vol 19 (2) ◽  
pp. 136-151
Author(s):  
Shivani Singh ◽  
Meenakshi Dhanawat ◽  
Sumeet Gupta ◽  
Deepak Kumar ◽  
Saloni Kakkar ◽  
...  

: Alzheimer’s disease (AD) is a multifarious and developing neurodegenerative disorder. The treatment of AD is still a challenge and availability of drug therapy on the basis of symptoms is not up to the mark. In the context of existence, which is getting worse for the human brain, it is necessary to take care of all critical measures. The disease is caused due to multidirectional pathology of the body, which demands the multi-target-directed ligand (MTDL) approach. This gives hope for new drugs for AD, summarized here in with the pyrimidine based natural product inspired molecule as a lead. The review is sufficient in providing a list of chemical ingredients of the plant to cure AD and screen them against various potential targets of AD. The synthesis of a highly functionalized scaffold in one step in a single pot without isolating the intermediate is a challenging task. In few examples, we have highlighted the importance of this kind of reaction, generally known as multi-component reaction. Multi-component is a widely accepted technique by the drug discovery people due to its high atom economy. It reduces multi-step process to a one-step process, therefore the compounds library can be made in minimum time and cost. This review has highlighted the importance of multicomponent reactions by giving the example of active scaffolds of pyrimidine/fused pyrimidines. This would bring importance to the fast as well as smart synthesis of bio-relevant molecules.


2011 ◽  
Vol 1323 ◽  
Author(s):  
Joachim D. Pedersen ◽  
Kwok Siong Teh

ABSTRACTThis paper reports a plasma-assisted, rapid, ambient-pressure, low-temperature one-step process for depositing conformal, non-porous nanocrystalline ZnO thin film on various substrates ranging from Si (100), fused quartz, glass, muscovite, c- and a-plane sapphire (Al2O3), to the common polymer polyimide (KaptonTM). The as-synthesized polycrystalline films range in thickness from 20nm to 200nm, deposited at a growth rate ranging from 2 nm/min to 50 nm/min. The lowest deposition temperature achieved with this method is 180°C and progress is being made in further lowering this temperature. The as-deposited films are highly oriented in the caxis, with (002) being the dominant planes.


2019 ◽  
Author(s):  
Mark Workentin ◽  
François Lagugné-Labarthet ◽  
Sidney Legge

In this work we present a clean one-step process for modifying headgroups of self-assembled monolayers (SAMs) on gold using photo-enabled click chemistry. A thiolated, cyclopropenone-caged strained alkyne precursor was first functionalized onto a flat gold substrate through self-assembly. Exposure of the cyclopropenone SAM to UV-A light initiated the efficient photochemical decarbonylation of the cyclopropenone moiety, revealing the strained alkyne capable of undergoing the interfacial strain-promoted alkyne-azide cycloaddition (SPAAC). Irradiated SAMs were derivatized with a series of model azides with varied hydrophobicity to demonstrate the generality of this chemical system for the modification and fine-tuning of the surface chemistry on gold substrates. SAMs were characterized at each step with polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) to confirm successful functionalization and reactivity. Furthermore, to showcase the compatibility of this approach with biochemical applications, cyclopropenone SAMs were irradiated and modified with azide-bearing cell adhesion peptides to promote human fibroblast cell adhesion, then imaged by live cell fluorescence microscopy. Thus, the “photoclick” methodology reported here represents an improved, versatile, catalyst-free protocol that allows for a high degree of control over the modification of material surfaces, with applicability in materials science as well as biochemistry.<br>


Alloy Digest ◽  
1989 ◽  
Vol 38 (1) ◽  

Abstract UNS NO6455 is a nickel-chromium-molybdenum alloy with outstanding high-temperature stability as shown by high ductility and corrosion resistance even after long-time aging in the range 1200-1900 F. The alloy also has excellent resistance to stress-corrosion cracking and to oxidizing atmospheres up to 1900 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-367. Producer or source: Nickel and nickel alloy producers.


Alloy Digest ◽  
1987 ◽  
Vol 36 (7) ◽  

Abstract UNS No. R54620 is an alpha-beta titanium alloy. It has an excellent combination of tensile strength, creep strength, toughness and high-temperature stability that makes it suitable for service to 1050 F. It is recommended for use where high strength is required. It has outstanding advantages for long-time use at temperatures to 800 F. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ti-86. Producer or source: Titanium alloy mills.


The temperature factor is one of the limiting factors for obtaining high yields of crops, so one of the main tasks of selection is to search for temperature-resistant genotypes and to create on their basis the banks of crops with high temperature stability. The first step to solving this problem is to conduct a rapid assessment of the temperature plasticity of large populations and to isolate breeding-valuable genotypes from them. There are numerous methods that allow, in the short term with minimal technical and material costs, to carry out an initial assessment of a large number of genotypes at sporophytic level and differentiate them by resistance to the temperature factor. These methods include the method of estimating pollen populations. These studies have repeatedly been conducted on many cultures, their correctness is due to the expression of a large part of the plant genome, both at the diploid and haploid levels of development and demonstrated by many studies in this direction. The aim of our study was to study the stability of gametophyte and sporophyte of collecting varieties and varieties of winter rape to elevated temperatures, to study the correlation between the heat resistance of sporophyte and gametophyte.


2007 ◽  
Vol 336-338 ◽  
pp. 498-501
Author(s):  
Xian Feng Jiang ◽  
Min Fang Han ◽  
Su Ping Peng

The all processes for manufacturing materials parts of solid oxide fuel cell (SOFC) are discussed in the paper. The films are made in one step by the ways of APS, VPS, EVD, which are usually used to produce the electrolyte and interconnect. The films are thin and good gas-resistance, but with relatively high cost. All parts of SOFC are made by the following ways, such as sol-gel, tape casting, tape calendaring and screen printing, which are suitable for manufacturing samples in industry with the cheapest process by co-sintered together ways.


2021 ◽  
Vol 10 (4) ◽  
pp. 675-703
Author(s):  
Dongxu Li ◽  
Xiaojun Zeng ◽  
Zhipeng Li ◽  
Zong-Yang Shen ◽  
Hua Hao ◽  
...  

AbstractDielectric ceramic capacitors, with the advantages of high power density, fast charge-discharge capability, excellent fatigue endurance, and good high temperature stability, have been acknowledged to be promising candidates for solid-state pulse power systems. This review investigates the energy storage performances of linear dielectric, relaxor ferroelectric, and antiferroelectric from the viewpoint of chemical modification, macro/microstructural design, and electrical property optimization. Research progress of ceramic bulks and films for Pb-based and/or Pb-free systems is summarized. Finally, we propose the perspectives on the development of energy storage ceramics for pulse power capacitors in the future.


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