pulsed injection
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Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 605
Author(s):  
Voitech Stankevic ◽  
Nerija Zurauskiene ◽  
Skirmantas Kersulis ◽  
Valentina Plausinaitiene ◽  
Rasuole Lukose ◽  
...  

The results of colossal magnetoresistance (CMR) properties of La0.83Sr0.17Mn1.21O3 (LSMO) films grown by pulsed injection MOCVD technique onto various substrates are presented. The films with thicknesses of 360 nm and 60 nm grown on AT-cut single crystal quartz, polycrystalline Al2O3, and amorphous Si/SiO2 substrates were nanostructured with column-shaped crystallites spread perpendicular to the film plane. It was found that morphology, microstructure, and magnetoresistive properties of the films strongly depend on the substrate used. The low-field MR at low temperatures (25 K) showed twice higher values (−31% at 0.7 T) for LSMO/quartz in comparison to films grown on the other substrates (−15%). This value is high in comparison to results published in literature for manganite films prepared without additional insulating oxides. The high-field MR measured up to 20 T at 80 K was also the highest for LSMO/quartz films (−56%) and demonstrated the highest sensitivity S = 0.28 V/T at B = 0.25 T (voltage supply 2.5 V), which is promising for magnetic sensor applications. It was demonstrated that Mn excess Mn/(La + Sr) = 1.21 increases the metal-insulator transition temperature of the films up to 285 K, allowing the increase in the operation temperature of magnetic sensors up to 363 K. These results allow us to fabricate CMR sensors with predetermined parameters in a wide range of magnetic fields and temperatures.


2021 ◽  
Vol 13 (7) ◽  
pp. 1215-1222
Author(s):  
Néstor Méndez-Lozano ◽  
Miguel Apátiga-Castro ◽  
E. M. Rivera-Muñoz ◽  
Alejandro Manzano-Ramírez ◽  
Rodrigo Velázquez-Castillo

ABSTRACTAmorphous calcium phosphate particles were synthesized for the first time by the Pulsed Injection Chemical Vapor Deposition technique onto silicon wafers, using Trimethyl Phosphate and Calcium Lactate mixed in a methanol solution as the precursor. The particles were deposited at a substrate temperature of 500, 550, and 600 °C obtaining the best results at 500 °C in terms of nucleation, density, morphology, and Ca/P ratio. The functional groups and vibrational modes, elemental composition, and surface morphology, were studied using Fourier Transform Infrared Spectroscopy, Raman Spectroscopy, and X-ray Energy Dispersion Spectrometry, and Scanning Electron Microscopy, respectively. The presence of the phosphate group characteristic of calcium phosphate was also observed. Uniform growth of the microstructures as the growth time and the temperature of the substrate increases were also observed, together with agglomerates of calcium phosphate in microstructures of 10, 50, and 100 nm in diameter. In these calcium phosphate agglomerates, calcium and phosphorus presence were observed, which is an important feature due to the Ca/P ratio gives information regarding biocompatibility.


Author(s):  
Sujin Park ◽  
Ji-Hwan Seol ◽  
Li Xu ◽  
Dennis Sylvester ◽  
David Blaauw
Keyword(s):  

2021 ◽  
pp. 2101375
Author(s):  
Yi Zhu ◽  
Bowen Wang ◽  
Ziyuan Li ◽  
Jian Zhang ◽  
Yilin Tang ◽  
...  

Author(s):  
Philipp A. Pickerodt ◽  
Moritz B. T. Hofferberth ◽  
Thilo Busch ◽  
Martin Russ ◽  
Mahdi Taher ◽  
...  

Abstract Purpose Admixture of nitric oxide (NO) to the gas inspired with mechanical ventilation can be achieved through continuous, timed, or pulsed injection of NO into the inspiratory limb. The dose and timing of NO injection govern the inspired and intrapulmonary effect site concentrations achieved with different administration modes. Here we test the effectiveness and target reliability of a new mode injecting pulsed NO boluses exclusively during early inspiration. Methods An in vitro lung model was operated under various ventilator settings. Admixture of NO through injection into the inspiratory limb was timed either (i) selectively during early inspiration (“pulsed delivery”), or as customary, (ii) during inspiratory time or (iii) the entire respiratory cycle. Set NO target concentrations of 5–40 parts per million (ppm) were tested for agreement with the yield NO concentrations measured at various sites in the inspiratory limb, to assess the effectiveness of these NO administration modes. Results Pulsed delivery produced inspiratory NO concentrations comparable with those of customary modes of NO administration. At low (450 ml) and ultra-low (230 ml) tidal volumes, pulsed delivery yielded better agreement of the set target (up to 40 ppm) and inspiratory NO concentrations as compared to customary modes. Pulsed delivery with NO injection close to the artificial lung yielded higher intrapulmonary NO concentrations than with NO injection close to the ventilator. The maximum inspiratory NO concentration observed in the trachea (68 ± 30 ppm) occurred with pulsed delivery at a set target of 40 ppm. Conclusion Pulsed early inspiratory phase NO injection is as effective as continuous or non-selective admixture of NO to inspired gas and may confer improved target reliability, especially at low, lung protective tidal volumes.


2020 ◽  
Author(s):  
Yi Zhu ◽  
Bowen Wang ◽  
Ziyuan Li ◽  
Jian Zhang ◽  
Yilin Tang ◽  
...  

Abstract High-efficiency and wavelength-tunable light emitting diode (LED) devices will play an important role in future advanced optoelectronic systems. Traditional semiconductor LED devices typically have a fixed emission wavelength that is determined by the energy of the emission states. Here, we developed a novel high-efficiency and wavelength-tunable monolayer WS2 LED device, which operates in the hybrid mode of continuous-pulsed injection. This hybrid injection enables highly enhanced emission efficiency (> 20 times) and the effective size of emission area (> 5 times) at room temperature. The emission wavelength of WS2 monolayer LED device can be tuned over more than 40 nm by driving AC voltages, from exciton emission to trion emission, and further to defect emissions. The quantum efficiency of defect electroluminescence (EL) emission is measured to be more than 24.5 times larger than that from free exciton and trion EL emissions. The separate carrier injection in our LED also demonstrate advantage in allowing to visualize and distinguish defect species in real space. Those defects are assigned to be negatively charged defects. Our results open a new route to develop high-performance and wavelength-tunable LED devices for future advanced optoelectronic applications.


Fuel ◽  
2019 ◽  
Vol 257 ◽  
pp. 116081 ◽  
Author(s):  
Yan Lei ◽  
Jiaxing Liu ◽  
Tao Qiu ◽  
Yunqiang Li ◽  
Yupeng Wang ◽  
...  

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