scholarly journals Single-crystalline perovskite wafers with a Cr blocking layer for broad and stable light detection in a harsh environment

RSC Advances ◽  
2018 ◽  
Vol 8 (27) ◽  
pp. 14848-14853 ◽  
Author(s):  
Qian Wang ◽  
Dongliang Bai ◽  
Zhiwen Jin ◽  
Shengzhong (Frank) Liu

Perovskite single-crystalline wafer based photodetectors are prepared with broad photodetection, and show little degradation at high-temperature or with storage under ambient-conditions.

2010 ◽  
Vol 97 (22) ◽  
pp. 223507 ◽  
Author(s):  
H. H. Radamson ◽  
M. Kolahdouz ◽  
S. Shayestehaminzadeh ◽  
A. Afshar Farniya ◽  
S. Wissmar

Author(s):  
Britta Laux ◽  
Sebastian Piegert ◽  
Joachim Ro¨sler

High temperature diffusion brazing is a very important technology for filling cracks in components from single-crystalline nickel-base superalloys as used in aircraft engines and stationary gas turbines: alloys, which are similar to the base material, are enhanced by a fast diffusing melting-point depressant (MPD) like boron or silicon, which causes solidification by diffusing into the base material. Generally, epitaxial solidification of single-crystalline materials can be achieved by use of conventional braze alloys, however, very long hold times are necessary to provide a complete diffusion of the MPD out of the braze gap. If the temperature is lowered before diffusion is completed, brittle secondary phases precipitate, which serve as nucleation sites for stray grains and, therefore, lead to deteriorating mechanical properties. It was demonstrated in earlier works that nickel-manganese-based braze alloys are appropriate systems for the braze repair of particularly wide gaps in the range of more than 200 μm, which allow a significant shortening of the required hold times. This is caused by the complete solubility of manganese in nickel: epitaxial solidification can be controlled by cooling in addition to diffusion. In this work, it will be shown that the nickel-manganese-based systems can be enhanced by chromium and aluminium, which is with regard to high-temperature applications a very important aspect. Furthermore, it will be demonstrated that silicon, which could be identified as appropriate secondary MPD in recent works, can be replaced by titanium, as this element has additionally a γ′ stabilizing effect. Several braze alloys containing nickel, manganese, chromium, aluminium and titanium will be presented. Previously, the influence of the above mentioned elements on the nickel-manganese-based systems will be visualized by thermodynamic simulations. Afterwards, different compositions in combination with a heat treatment, which is typical for nickel-base superalloys, will be discussed: a microstructure, which is very similar to that within the base material can be presented.


2009 ◽  
Vol 1 (1) ◽  
pp. 963-966 ◽  
Author(s):  
G. Tortissier ◽  
L. Blanc ◽  
A. Tetelin ◽  
J-L. Lachaud ◽  
M. Benoit ◽  
...  

Food Research ◽  
2019 ◽  
pp. 808-813
Author(s):  
Ubong A. ◽  
C.Y. New ◽  
L.C. Chai ◽  
Nur Fatihah A. ◽  
Nur Hasria K. ◽  
...  

Bacillus cereus spores are capable of surviving the harsh environment and more often, they cause great concern to the dairy industry. The current research was conducted to study the effect of temperature on germination and growth of B. cereus spores in UHT chocolate milk; the study was carried out at 8°C, 25°C and 35°C over a span of seven days. The results showed that no growth was observed at 8°C. At 25°C, a rapid increase in growth was observed as early as Day 1, from an initial count of ten spores to 4.01 log10 CFU/mL. Meanwhile, at 35°C, the growth on Day 1 was more rapid in which the count promptly increased to 8.07 log10 CFU/mL. Analysis of graph trend showed that the number of vegetative cells decreased while the number of spores increased with incubation time due to nutrients exhaustion. This study fills up the data gap towards understanding the possible issues that might arise in the actual scenario and at the same time, suggests a suitable approach to minimize infection risk caused by B. cereus spores.


1997 ◽  
Vol 481 ◽  
Author(s):  
Michael F. Bell ◽  
Georges Dénès ◽  
Zhimeng Zhu

ABSTRACTPrecipitation reactions from aqueous solutions of calcium nitrate and tin(II) fluoride result in the formation of two metastable phases, depending on the reaction conditions. Crystalline CaSn2F6 and the microcrystalline Ca1-xSnxF2 solid solution are obtained, the latter crystallizing in the cubic fluorite (CaF2) type with total Ca/Sn disorder. Both phases are fluoride ion conductors. Electrical conductivity measurements versus temperature and bulk density measurements show that both phases are far from thermodynamic equilibrium at ambient conditions, and thus are metastable. Both decompose to a mixture of SnF2 and CaF2 at high temperature. In addition, CaSn2F6 is chemically unstable in an aqueous medium, in which it looses SnF2 to give the microcrystalline Ca1-xSnxF2 solid solution.


2013 ◽  
Vol 2013 (HITEN) ◽  
pp. 000075-000081
Author(s):  
Ramesh Khanna ◽  
Srinivasan Venkataraman

Harsh Environment approved components/ designs require high reliability as well as availability of power to meet their system needs. The paper will explore the various design constrains imposed on the high temperature designs. Down hole oil and gas industry requires high reliability components that can withstand high temperature. Discrete component selection, packaging and constrains imposed by various specification requirements to meet harsh environment approval are critical aspect of high-temp designs. High temperature PCB material, PCB layout techniques, trace characteristics are an important aspect of high-temperature PCB design and will be explored in the article. Buck Converters are the basic building blocks, but in order to meet system requirements to power FPGA's where low output voltage and high currents are required. Converter must be able to provide wider step down ratios with high transient response so buck converters are used. The paper with explore the various features of a buck-based POL converter design. Low noise forces the need for Low-dropout (LDO) Regulators that can operate at high Temperatures up to 210°C. This paper will address the power requirements to meet system needs.


2015 ◽  
Vol 2015 (HiTEN) ◽  
pp. 000111-000115
Author(s):  
Piers R. Tremlett

A polymer based electronic packaging system has been developed that is capable of operating at temperatures over 175°C and up to 225°C. This system is being developed to be a lead free, non-hermetic and able to deliver miniature or functionally dense circuits. It will be suitable for sensor systems where amplification, signal digitisation and autonomy are important whilst operating in a harsh environment such as high temperature.


Fuel ◽  
2014 ◽  
Vol 135 ◽  
pp. 340-351 ◽  
Author(s):  
Ji Zhang ◽  
Wei Jing ◽  
William L. Roberts ◽  
Tiegang Fang

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