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The inexpensive, endurable sealing members are among the key components determining the performance and durability of proton exchange membrane fuel cells (PEMFCs). However, there is a lack of effective in situ measurement to monitor the sealing performance change in the fuel cell operation environment. Therefore, the durability of a sealing material should be assessed previously to its application. The present work investigates four types of commercially available sealing silicone rubbers, and five groups of aging tests are carried out to compare their properties and durability in a simulated PEMFC environment, including compression set, stress relaxation, compression stress–strain, solution soaking, and low‐temperature characterization. Furthermore, to comprehensively evaluate the performance of these four types of silicone rubbers and screen out the most suitable one, a comprehensive evaluation table of sealing materials selection based on weight factor was established through an expert survey method, by which the experimental results of all the silicone rubbers can be weighted and scored. This method can be widely used in the fuel cell industry. [ABSTRACT FROM AUTHOR]

Perfluoro sulfonic acid (PFSA)-membrane fuel cells for heavy-duty vehicle applications require elevated operating temperature, which may negatively impact the durability of proton exchange membrane fuel cells (PEMFCs). This study evaluated a 10 kW stack by conducting a 100 h driving cycle test in near-water boiling temperature. Performance degradation varied in different regions of the membrane electrode assembly (MEA), with severe degradation observed near the coolant outlet (near-water boiling temperature) and the hydrogen inlet. The rapid degradation of the MEA was examined through an analysis of its electrochemical properties, morphology, pore size, mechanical properties, degree of graphitization, and elemental composition in different regions. It was found that elevated temperatures accelerated the degradation of the PEM, leading to polymer melting, corrosion of carbon support, and the aggregation and growth of Pt nanoparticles within the MEA, ultimately the MEA structural breakdown. the MEA supporting structural breakdown. The combination of high temperatures and the loss of fluoride ions from the MEA resulted in damage to the bipolar plate coatings. Under the collaborative influence of these factors, the average voltage degradation rate of the PEMFC stack was 1.44 %@1.0 A cm−2, and the single cell with the worst degradation was up to 8.6 %@1.0 A cm−2. [ABSTRACT FROM AUTHOR]

Chitinase-3 like-protein-1 (CHI3L1), a glycoprotein belonging to the glycoside hydrolase family 18, binds to chitin; however, this protein lacks chitinase activity. Although CHI3L1 is not an enzyme capable of degrading chitin, it plays significant roles in abnormal glucose and lipid metabolism, indicating its involvement in metabolic disorders. In addition, CHI3L1 is considered a key player in inflammatory diseases, with clinical data suggesting its potential as a predictor of cardiovascular disease. CHI3L1 regulates the inflammatory response of various cell types, including macrophages, vascular smooth muscle cells and fibroblasts. In addition, CHI3L1 participates in vascular remodeling and fibrosis, contributing to the pathogenesis of cardiovascular disease. At present, research is focused on elucidating the role of CHI3L1 in cardiovascular disease. The present systematic review was conducted to comprehensively evaluate the effects of CHI3L1 on cardiovascular cells, and determine the potential implications in the occurrence and progression of cardiovascular disease. The present study may further the understanding of the involvement of CHI3L1 in cardiovascular pathology, demonstrating its potential as a therapeutic target or biomarker in the management of cardiovascular disease. [ABSTRACT FROM AUTHOR]

Tip enhanced Raman spectra of AB-stacked bilayer graphene (BLG) and twisted bilayer graphene (TwBLG) nanofragments have been studied by using density functional theory. Different from a normal Raman spectrum of BLG, a unique Raman band Gr+ is observed in its tip enhanced Raman spectrum and assigned as a split of the G band. We attribute this split to the nonuniformity distribution of the charge on carbon atoms. Compared with BLG, the Gr+ band intensity of TwBLG is dramatically enhanced at a small twist angle and decreases with the angle increasing. Interlayer Coulomb interaction represented in the Gr+ mode of TwBLG matches well with the atom vibration strength distribution of the Gr+ band at different twist angles, and thereby the properties of the Gr+ band can be tuned by the twisted angle. The results may help to further understand the Raman spectra of TwBLG and provide deep insights for exploring vibrational modes of two-dimensional nanomaterials. [ABSTRACT FROM AUTHOR]

Nonthermal plasma (NTP) can oxidize and decompose particulate matter (PM) of diesel engines at low temperatures (≤200°C), exhibiting good application prospects. PM samples were collected under different diesel engine loads and were oxidized using an NTP method. The volatile fraction (VF) mass fraction of the PM samples decreases under low engine loads (<70%) and increases under high engine loads (≥70%) after the NTP treatment. NTP can remove aldehyde groups in PM and weaken the volatilization of PM. A higher temperature is needed for the VF to reach its maximum volatilization rate after the NTP treatment. The relative content of the small molecules is significantly higher after the NTP treatment. [ABSTRACT FROM AUTHOR]

The garnet-type solid Li-ion conductor, Li6.4La3Zr1.4Ta0.6O12, is viewed as a promising solid-state electrolyte for the next-generation high-performance Li-ion battery because of its high ionic conductivity and stability. The previous researches, in order to avoid Li volatilization loss during solid-state reaction of sintering, mother powder with the same composition as green bodies was usually used to cover the samples, it would waste the expensive raw materials and increase the fabrication cost. In this study, a new method was proposed to prepare the Li6.4La3Zr1.4Ta0.6O12 ceramic solid-state electrolyte where the Li loss is compensated by the outside Li2CO3. Samples prepared by this method have pure garnet phase and compact micromorphology with few pores. These samples have a high Li-ion conductivity of 2.9×10−4 S/cm and a low activation energy of 0.37 eV at room temperature. The electronic conductivity is 1.08×10−8 S/cm, which can be neglected for solid-state electrolyte. [ABSTRACT FROM AUTHOR]