ABSTRACT
High Li+ conductivity, good interfacial compatibility, and nano-scale particle size have always been essential conditions for selecting inorganic fillers in high-performance composite solid electrolytes. In this study, non-milled in situ LLZO fillers with nanosize was synthesized via the sol-gel method by rapid heating sintering, which resulted in more surface defects and fewer impurities in LLZO. Compared with milled LLZO fillers, these non-milled LLZO fillers with more surface defects and fewer impurities can effectively reduce the crystallinity of PEO and agglomeration in PEO, which can form composite electrolytes with high Li+ conductivity. Most importantly, the discharge capacity of the 7.5% non-milled LLZO-PEO-based LiFePO4/Li battery is about 135.5 mA h g-1 at 1C and 60 °C. After 100 cycles, the discharge specific capacity remains at 99%. It is worth noting that nano-sized non-milled LLZO will improve the discharge capacity of LiFePO4/Li batteries to 122.1 mA h g-1 at 0.2C and 30 °C.
ABSTRACT
Magnesium phosphate cement (MPC) is a potential inorganic binder for steel coating due to setting and hardening rapidly, and bonding tightly with steel. NH4H2PO4-based MPC as a fire-retardant coating for steel was investigated in this work. MPC coatings were prepared from MPC paste and MPC mortar with expanded vermiculite (EV). The physical-mechanical properties and fireproof performance of MPC coatings were investigated in detail. An infrared thermal imager was employed to collect the temperature distribution and temperature rise with time on the coating samples automatically. The X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) analyses were carried out on the MPC coating after the fireproof test. Re-fire test and corrosion resistance were performed preliminarily on the MPC coating. The results showed that the fireproof performance of MPC coating met the fire protection requirement for steel as long as the thickness of the MPC paste coating was up to 10 mm, while the thickness of MPC mortar coating decreased to 4 mm when adding 40% EV (by mass). Dehydration and decomposition of reacted products in the hardened MPC coating were, to some extent, contributed to the excellent fireproof performance during the fire test. The slight ceramic formation and integration of MPC coating during the fire test would compensate for the decreasing of strength due to the dehydration and decomposition, so that the MPC coating would keep certain fireproof performance when undergoing fire again. MPC is suitable for a fire-retardant coating, while higher tensile bonding strength with steel and potential corrosion resistance on steel, as well as rapid surface drying and hardening can be achieved.
ABSTRACT
This paper presents the design and fabrication of an infrared scanning and tracking system for detecting mid-wave infrared (MWIR) spectral characteristics of moving targets. The infrared spectra and infrared image are integrated in this system, which is mainly composed of a two-dimensional (2D) scanning mirror, dual-band infrared lens, long-wave infrared imaging unit, MWIR spectrum-measuring unit, and processing-controlling unit. After describing the design specifications of this system, this paper analyzes the detection method and then describes how the tracking was realized by controlling the 2D scanning mirror. Experiments were carried out to verify its feasibility.
ABSTRACT
Group 13 metal atoms react with ethers under matrix isolation conditions to give a number of interesting products. This work has been extended to include the reaction of Al atoms with 1,2-epoxybutane (CH(3)CH(2)H(2)) and its isotopomers, 1,2-epoxybutane-1,1-d(2) (CH(3)CH(2)D(2)) and 1,2-epoxybutane-2-d(1) (CH(3)CH(2)H(2)). The paramagnetic species generated in the reaction have been studied by electron paramagnetic resonance (EPR) spectroscopy. Two divalent Al insertion products were spontaneously formed. Species A, with the magnetic parameters a(Al) = 855 MHz, a(H)(1) = 28.8 MHz, a(H)(2) = 13.6 MHz, and g = 2.0014, is the C(1)-O insertion radical CH(3)CH(2). Species B, thought to result from the insertion of Al atoms into the C(2)-O bond, CH(3)CH(2), has the magnetic parameters g = 2.0003, a(Al) = 739 MHz, a(H)(1) = 15.1 MHz, a(H)(2) = 18.5 MHz, and a(H)(1) = 37.8 MHz. Support for these assignments was obtained by comparing the experimental values of the Al and H hyperfine interaction (hfi) with those calculated using a DFT method. At temperatures < 150 K, there is evidence for the formation of the alkyl radical CH(3)CH(2)CH(O(-))CH(2)* due to ring opening at the C(1)-O bond, while at higher temperatures a radical with magnetic parameters similar to those reported for 1-methallyl was detected.
