The rapid, broad wavelength scanning capabilities of advanced diode lasers allow extension of traditional diode-laser absorption techniques to high pressure, transient, and generally hostile environments. Here, we demonstrate this extension by applying a vertical cavity surface-emitting laser (VCSEL) to monitor gas temperature and pressure in a pulse detonation engine (PDE). Using aggressive injection current modulation, the VCSEL is scanned through a 10 cm-1 spectral window at megahertz rates - roughly 10 times the scanning range and 1000 times the scanning rate of a conventional diode laser. The VCSEL probes absorption lineshapes of the ~ 852 nm D2 transition of atomic Cs, seeded at ~ 5 ppm into the feedstock gases of a PDE. Using these lineshapes, detonated-gas temperature and pressure histories, spanning 2000 - 4000 K and 0.5 - 30 atm, respectively, are recorded with microsecond time response. The increasing availability of wavelength-agile diode lasers should support the development of similar sensors for other harsh flows, using other absorbers such as native H2O.
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http://dx.doi.org/10.1364/oe.10.000505 | DOI Listing |
Acc Chem Res
May 2024
Advanced Materials and Catalysis Group, Center of Chemistry for Frontier Technologies, State Key Laboratory of Clean Energy Utilization, Institute of Catalysis, Department of Chemistry, Zhejiang University, Hangzhou 310058, P. R. China.
ConspectusThe development of an advanced energy conversion system for water electrolysis with high efficiency and durability is of great significance for a hydrogen-powered society. This progress relies on the fabrication of electrocatalysts with superior electrochemical performance. Despite decades of advancements in exploring high-performance noble and non-noble metal electrocatalysts, several challenges persist at both the micro- and macrolevels in the field of water electrolysis.
View Article and Find Full Text PDFJ Colloid Interface Sci
July 2023
Qingyuan Innovation Laboratory, Quanzhou, Fujian 362801, China; Fujian Engineering Research Center of Advanced Manufacturing Technology for Fine Chemicals, College of Chemical Engineering, Fuzhou University, Fuzhou, Fujian 350108, China. Electronic address:
The study about simultaneously enhancing the resistive switching level and ambient-air-stability of perovskite-based memorizers will promote its commercialization. Here, a new 3D perovskite (TAZ-H)PbBr (TAZ-H = protonated thiazole) has been fabricated as FTO/(TAZ-H)PbBr/Ag device, which only exhibits binary memory performance with the high tolerant temperature of 170 °C. After encapsulating by polyvinylpyrrolidone (PVP), the (TAZ-H)PbBr@PVP composite-based device can demonstrate ternary resistive switching behavior with considerable ON2/ON1/OFF ratio (10: 10:1) and high ternary yield (68 %).
View Article and Find Full Text PDFActa Pharm Sin B
March 2023
National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610041, China.
Establishment of vaginal immune defenses at the mucosal interface layer through gene vaccines promise to prevent infectious diseases among females. Mucosal barriers composed of a flowing mucus hydrogel and tightly conjugated epithelial cells (ECs), which represent the main technical difficulties for vaccine development, reside in the harsh, acidic human vaginal environment. Different from frequently employed viral vectors, two types of nonviral nanocarriers were designed to concurrently overcome the barriers and induce immune responses.
View Article and Find Full Text PDFMicromachines (Basel)
February 2023
College of Mechanical and Vehicle Engineering, Changchun University, Changchun 130022, China.
Since shaft parts operate under harsh environments for a long time, many critical parts suffer from corrosion, wear and other problems, leading to part failure and inability to continue in service. It is imperative to repair failed parts and increase their service life. An orthogonal experimental scheme is designed to numerically simulate the process of laser cladding of Inconel 718 alloy powder on 4140 alloy structural steel based on the ANSYS simulation platform, derive the relationship equation of cladding layer thickness according to the heat balance principle, establish a finite element model, couple three modules of temperature field, stress field and fluid field, and analyze different modules to realize the monitoring of different processes of laser cladding.
View Article and Find Full Text PDFSci China Life Sci
July 2023
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
The uplift of the Tibetan Plateau significantly altered the geomorphology and climate of the Euroasia by creating large mountains and rivers. Fishes are more likely to be affected relative to other organisms, as they are largely restricted to river systems. Faced with the rapidly flowing water in the Tibetan Plateau, a group of catfish has evolved greatly enlarged pectoral fins with more numbers of fin-rays to form an adhesive apparatus.
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