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The correlation between strain rates and the mechanical properties of HTPB propellant with 90% solid content (mass fraction) was investigated by uniaxial tensile tests at different tensile rates, and the tensile fracture surface was observed by scanning electron microscope (SEM). The effects of strain rate on the mechanical properties and failure mechanisms of the propellant were analyzed. The results show that the stress--strain curve of the propellant appears an arc segment phenomenon at low tensile rates. With the increase of tensile rates, the stress--strain curves of propellant gradually changes from 5 segment to 4 segment. The initial modulus and the maximum tensile strength of the propellant show an increasing trend with an increase in the tensile rates. The maximum elongation of the propellant decreases with an increase in the strain rate, and the maximum elongation of propellant is only 33.9% when the strain rate is 1 190.48 X 10 4s 1 . With the increase of strain rate, the failure mechanism of propellant gradually changes from particle dehumidification to matrix tearing, without particle fragmentation. [ABSTRACT FROM AUTHOR]

The Line laser gear measuring center (LLGMC) is an innovative gear measurement equipment that offers high efficiency but low accuracy. One crucial factor that influences its measurement accuracy is the presence of geometric errors. In this study, we conducted a thorough analysis of these geometric errors and proposed a method for modeling spatial errors. Instead of directly considering the geometric errors, we replaced them with the installation errors of the gear and line laser probe. This approach simplifies and improves the error transmission relationship. Subsequently, the installation errors are converted into a unified representation of the height error of the incident light from the line laser. A spatial error model that considers nine installation errors is then further established. By numerically calculating the sensitivity of different error sources, we effectively identified the errors that have a significant impact on the accuracy of LLGMC. Moreover, accuracy distribution is carried out to ensure that LLGMC can meet the measurement accuracy requirements for gears with a tolerance class of 6. This article provides a theoretical foundation for the structural design and accuracy assurance of LLGMC during the research and development phase. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive theory for wavelength modulation laser heterodyne spectroscopy is presented. Some necessary simplifications based on the Taylor series are introduced, the general formulas employed to demodulate the first harmonic signal (1f), the second harmonic signal (2f), and higher harmonic signal (nf) are derived in details, and hence the formulas are suitable for an arbitrary intensity modulation amplitude and modulation index. The purpose of this paper: an overview of how the laser heterodyne harmonic signal depends on the experimental parameters of intensity modulation amplitude and modulation index is reported. This overview is helpful to choose these parameters for the best laser heterodyne harmonic signal because it initiated a new pathway for systematically analyzing the relationships between the experimental parameters and the laser heterodyne harmonic signal. [ABSTRACT FROM AUTHOR]

Network pharmacology was employed to probe into the mechanism of Fushen Granules in treating peritoneal dialysis-rela-ted peritonitis(PDRP) in rats. The main active components of Fushen Granules were searched against the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, and their targets were predicted. PDRP-related targets were retrieved from DisGeNET and other databases. The common targets shared by the drug and the disease were identified by the online tool, and protein-protein interaction(PPI) network of the common targets. The obtained 276 common targets were imported into DAVID for GO function enrichment and KEGG pathway enrichment. The main signaling pathway of Fushen Granules in the treatment of PDRP was predicted as Toll-like receptor 4(TLR4)/nuclear factor(NF)-κB. The rat model of uremia was induced by 5/6 nephrectomy. From two weeks after operation, the rat model of peritoneal dialysis(PD) was established by intraperitoneal injection of 20 mL dialysate with 1.25% glucose every day. The sham operation group and model group received 2 mL normal saline by gavage every day. The rats in Fushen Gra-nules groups were administrated with 2 mL solutions of low-(0.54 g·kg~(-1)), medium-(1.08 g·kg~(-1)) and high-dose(2.16 g·kg~(-1)) Fushen Granules every day. The bifico group received 2 mL(113.4 mg·kg~(-1)) of bifico solution every day. At the end of the 8th week, the levels of serum creatinine(Scr) and blood urea nitrogen(BUN) in each group were measured. The serum levels of hypersensitive C reactive protein(hs-CRP), tumor necrosis factor(TNF)-α, and interleukin(IL)-6 were measured, and the pathological changes in the colon tissue were observed by hematoxylin-eosin(HE) staining. The serum levels of lipopolysaccharide(LPS) and lipopolysaccharide-binding protein(LBP) of rats were measured, and the expression levels of LBP, TLR4, NF-κB p65, inhibitor of κB kinase α(IκBα), TNF-α, and IL-1β in the colon tissue were determined. Compared with sham operation group, the model group had abnormal structure of all layers of colon tissue, sparse and shorter intestinal villi, visible edema in mucosal layer, wider gap, obvious local inflammatory cell infiltration, significantly decreased body weight(P<0.01), and significantly increased kidney function index(Scr, BUN) content(P<0.01). Serum levels of inflammatory cytokines(hs-CRP, TNF-α, IL-6), LPS and LBP were significantly increased(P<0.01), protein expressions of LBP, TLR4, NF-κB p65, TNF-α and IL-1β were significantly increased(P<0.01), and protein expressions of IκBα were significantly decreased(P<0.01). Compared with model group, intestinal villi damage in colonic tissue of rats in low-, medium-and high-dose Fushen Granules groups and bifico group were alleviated to different degrees, edema in submucosa was alleviated, space was narrowed, and inflammatory cell infiltration in lamina propria was reduced. The contents of renal function index(Scr, BUN) and serum inflammatory factors(hs-CRP, TNF-α, IL-6) were significantly decreased(P<0.05 or P<0.01) in medium-and high-dose Fushen Granules groups and bifico group(P<0.05 or P<0.01). Serum LPS and LBP contents in Fushen Granules group and bifico group were significantly decreased(P<0.01), protein expressions of LBP, TLR4, NF-κB p65, TNF-α and IL-1β in Fushen Granules group were significantly decreased(P<0.05 or P<0.01), and protein expressions of IκBα were significantly increased(P<0.01). The expression of LBP protein in bifico group was significantly decreased(P<0.01). The results suggest that Fushen Granules can protect the residual renal function of PD rats, reduce the inflammatory response, and protect the colon tissue. Based on network pharmacology, TLR4/NF-κB pathway may be the main signaling pathway of Fushen granule in the treatment of PDRP. The results showed that Fushen Granules could improve intestinal inflammation and protect intestinal barrier to prevent PDRP by regulating the expression of key factors in TLR4/NF-κB pathway in colon of PD rats.