Rational direct synthesis of [Fe(Htrz)2(trz)](BF4) polymorphs: temperature and concentration effects.

Author(s):  
Marlene Palluel ◽  
Liza el Khoury ◽  
Nathalie Daro ◽  
Sonia Buffière ◽  
Michaël Josse ◽  
...  

The [Fe(Htrz)2trz](BF4) compound is probably the most studied in the spin crossover (SCO) community since it exhibits switching properties with a large temperature range of memory effect, just above room...

2020 ◽  
Vol 12 ◽  
Author(s):  
Fang Wang ◽  
Jingkai Wei ◽  
Caixia Guo ◽  
Tao Ma ◽  
Linqing Zhang ◽  
...  

Background: At present, the main problems of Micro-Electro-Mechanical Systems (MEMS) temperature detector focus on the narrow range of temperature detection, difficulty of the high temperature measurement. Besides, MEMS devices have different response characteristics for various surrounding temperature in the petrochemical and metallurgy application fields with high-temperature and harsh conditions. To evaluate the performance stability of the hightemperature MEMS devices, the real-time temperature measurement is necessary. Objective: A schottky temperature detector based on the metal/n-ZnO/n-Si structures is designed to measure high temperature (523~873K) for the high-temperature MEMS devices with large temperature range. Method: By using the finite element method (FEM), three different work function metals (Cu, Ni and Pt) contact with the n-ZnO are investigated to realize Schottky. At room temperature (298K) and high temperature (523~873K), the current densities with various bias voltages (J-V) are studied. Results: The simulation results show that the high temperature response power consumption of three schottky detectors of Cu, Ni and Pt decreases successively, which are 1.16 mW, 63.63 μW and 0.14 μW. The response temperature sensitivities of 6.35 μA/K, 0.78 μA/K, and 2.29 nA/K are achieved. Conclusion: The Cu/n-ZnO/n-Si schottky structure could be used as a high temperature detector (523~873K) for the hightemperature MEMS devices. It has a large temperature range (350K) and a high response sensitivity is 6.35 μA/K. Compared with traditional devices, the Cu/n-ZnO/n-Si Schottky structure based temperature detector has a low energy consumption of 1.16 mW, which has potential applications in the high-temperature measurement of the MEMS devices.


2019 ◽  
Vol 89 (6) ◽  
pp. 873
Author(s):  
Г.А. Малыгин ◽  
В.И. Николаев ◽  
В.М. Крымов ◽  
С.А. Пульнев ◽  
С.И. Степанов

AbstractWe have performed experimental and theoretical investigation of the anomalous form of the compression diagrams and shape memory restoration curves in Ni_49Fe_18Ga_27Co_6 alloy crystals deformed by uniaxial compression along the [011]_ A crystallographic direction ( A -austenite) in the temperature range of 200–350 K. It is found that in the investigated temperature range, all compression diagrams contain anomalous segments of smooth and sharp decrease in deforming stresses. It is shown that the segments of a smooth decrease in stress are associated with peculiarities in martensite reaction L1_2 → 14M, while segments of a sharp drop are due to instability of martensite reactions 14M → L1_0 and L1_2 → L1_0. A possible source of reaction instability is associated with interfacial stresses at the interfaces between the martensite and austenite phases (lamellas) due to different elastic moduli of contacting phases. The magnitude of these stresses is significant in the case of 14M → L1_0 and L1_2 → L1_0 transformations, which induces a sharp drop of the deforming stress, while the restoration of the shape memory effect is of a burst nature. It is established that the contribution of interfacial stresses to the free energy of martensite transformation is smaller than the dissipative (entropy) contribution to this energy; however, interfacial stresses higher than a certain threshold strongly affect transformation kinetics and, hence, determine the strongly anomalous shape of pseudoelastic deformation curves and burst restoration of the shape memory effect.


ACS Nano ◽  
2019 ◽  
Vol 13 (8) ◽  
pp. 8669-8679 ◽  
Author(s):  
Daipayan Sarkar ◽  
Peiyuan Kang ◽  
Steven O. Nielsen ◽  
Zhenpeng Qin

2020 ◽  
Vol 44 (9) ◽  
pp. 3771-3776
Author(s):  
Zhigang Peng ◽  
Chen Chen ◽  
Qian Feng ◽  
Yong Zheng ◽  
Huan Liu ◽  
...  

We synthesized a retarder, which has excellent thickening performance in the temperature range of 90–150 °C.


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