The objective of this paper is to investigate the effects of assisted ultrasonic vibration on the surface roughness of machined surfaces in micro-end-milling. Series of slot-milling experiments were ...conducted with aluminum alloy as workpiece material. The surface roughness of slot bottom surface and vertical side wall surface of slot was studied, respectively. It is found that surface roughness of the machined slot bottom surface could increase to varying degrees because of ultrasonic vibration in most of the studied cases, and this deterioration becomes more apparent when large feed per tooth and low-spindle speed were adopted. As for the vertical side wall surface of the slot, there is an obvious improvement of surface roughness when ultrasonic vibration is applied. Based on analysis of variance analysis, further study indicates that the surface roughness of vertical side wall surface of the slot is determined by several key parameters including spindle speed, feed per tooth and amplitude in ultrasonic vibration-assisted milling. An optimal combination of these parameters is of great benefit to achieving small surface roughness.
Reductions in bleeding rates and bulk shrinkage of grouting repair materials comprise the key to solving the leakage of earth-rock dams. In this paper, an anti-seepage grouting material for ...earth-rock dam was developed by introducing mineral admixtures and graphene oxide (GO) nano sheets into low-cost clay-cement grouting materials and by adding polycarboxylate superplasticizers (PCs) to improve slurry viscosity. The experimental results show that the shear stress and viscosity of the slurry increase with the increase in GO concentration, and the slurry has a certain thixotropy. GO can provide a platform to promote the formation of hydration products and fill the pores of clay particles due to its high specific surface area and low volume; in this paper, the microstructure of clay-cement-graphene oxide (CCGO) grouting materials were improved. Therefore, the bleeding rate, bulk shrinkage rate, setting time and unconfined compressive strength (UCS) of the sample were macroscopically improved. In particular, the bleeding rate and bulk shrinkage rate were shown to be 0% when the content of GO reached 1.08 g/kg. Thus, the grouting anti-seepage and reinforcement performance of CCGO grouting materials were improved.
The primary factors responsible for inducing landslide disasters are earthquakes and rainfall. Using the strength reduction method within the finite element analysis software Abaqus, a study was ...conducted to analyze the stability of coastal geotechnical slopes. This investigation considered the combined influence of rainfall and earthquakes, taking into account the geological conditions and characteristics specific to these coastal areas. The results indicate that, under the same seismic acceleration amplitude, the shear strength of the slope soil gradually decreases as the water content increases, resulting in a decrease in the stability coefficient. Similarly, with a constant water content in the slope, an increase in seismic acceleration amplitude leads to heightened soil shear stress, consequently decreasing the stability coefficient. Maintaining constant water content while increasing seismic acceleration results in elevated soil shear stress, reduced shear strength, and a subsequent decrease in the stability coefficient. The simultaneous occurrence of intense rainfall and a strong earthquake pushes the slope to its most precarious state, causing the most significant reduction in the stability coefficient. Incorporating anti-slip piles substantially enhances the slope’s stability coefficient, and an optimal arrangement of anti-slip piles for the most unfavorable conditions is proposed.
Magnesium isoglycyrrhizinate (MI) was extracted from roots of the plant Glycyrrhiza glabra, which displays multiple pharmacological activities such as anti-inflammation, anti-apoptosis, and ...anti-tumor. Here, we aimed to investigate the effect of MI on the progression and epithelial-mesenchymal transition (EMT) of laryngeal cancer.
Forty laryngeal cancer clinical samples were used. The role of MI in the proliferation of laryngeal cancer cells was assessed by MTT assay, Edu assay and colony formation assay. The function of MI in the migration and invasion of laryngeal cancer cells was tested by transwell assays. The effect of MI on apoptosis of laryngeal cancer cells was determined by cell apoptosis assay. The impact of MI on tumor growth in vivo was analyzed by tumorigenicity analysis using Balb/c nude mice. qPCR and Western blot analysis were performed to measure the expression levels of gene and protein, respectively.
We identified that EMT-related transcription factor Twist was significantly elevated in the laryngeal cancer tissues. The expression of Twist was also enhanced in the human laryngeal carcinoma HEP-2 cells compared with that in the primary laryngeal epithelial cells. The high expression of Twist was remarkably correlated with poor overall survival of patients with laryngeal cancer. Meanwhile, our data revealed that MI reduced cell proliferation, migration and invasion and enhanced apoptosis of laryngeal cancer cells in vitro. Moreover, MI decreased transcriptional activation and the expression levels of NF-κB and Twist, and alleviated EMT in vitro and in vivo. MI remarkably inhibited tumor growth and EMT of laryngeal cancer cells in vivo.
MI restrains the progression of laryngeal cancer and induces an inhibitory effect on EMT in laryngeal cancer by modulating the NF-κB/Twist signaling. Our finding provides new insights into the mechanism by which MI inhibits laryngeal carcinoma development, enriching the understanding of the anti-tumor function of MI.
A one-pot strategy for deoxygenative alkylation of alcohols with quinoxalin-2(1H)-ones was developed by using xanthate salts as alcohol-activating groups for radical generation in the presence of ...tricyclohexylphosphine under visible-light-promoted conditions. The remarkable features of this reaction include a broad substrate scope, excellent functional group tolerance, mild conditions, and simple operation. Moreover, the synthetic utility of this reaction was validated by the success of two-step one-pot reactions, scale-up synthesis, and chemoselective radical monodeoxygenation of diols.
A photochemical approach toward RCOCF
-substituted pyrrolo1,2-
indolediones was developed by the radical cascade difluoroalkylation/cyclization reaction of unactivated 1-acryloyl-2-cyanoindoles with ...ethyl iododifluoroacetate or iododifluoramides under visible-light irradiation. This transition-metal- and photosensitizer-free protocol afforded diverse difluoroalkylated pyrrolo1,2-
indolediones in moderate to good yields under mild reaction conditions. Most appealingly, the reaction can proceed smoothly under sunlight irradiation, which opens a new avenue toward difluoroalkylated pyrrolo1,2-
indolediones.
A photochemical approach toward RCOCF2-substituted pyrrolo1,2-aindolediones was developed by the radical cascade difluoroalkylation/cyclization reaction of unactivated 1-acryloyl-2-cyanoindoles ...with ethyl iododifluoroacetate or iododifluoramides under visible-light irradiation. This transition-metal- and photosensitizer-free protocol afforded diverse difluoroalkylated pyrrolo1,2-aindolediones in moderate to good yields under mild reaction conditions. Most appealingly, the reaction can proceed smoothly under sunlight irradiation, which opens a new avenue toward difluoroalkylated pyrrolo1,2-aindolediones.
Phosphogypsum-based cementitious materials (PGCM) are commonly selected as substitutes to ordinary Portland cement (OPC), however, drawbacks, such as a restricted capacity for CO2 sequestration and ...reduced mechanical properties upon carbonation, limit the potential applications of PGCM. This study investigates the carbonation process mechanism of PGCM and explores to modify the hydration product classes of PGCM by using two silica-rich solid wastes, which are waste glass powder (WGP) and silica fume (SF). This innovative approach resulted in an improved carbon capture capacity and enhanced mechanical properties of PGCM. The addition of SF and WGP increased the compression strength of PGCM by 15.5% and 19.0%, respectively. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were utilized to investigate the hydration mechanism of PGCM supplemented with SF and WGP, in order to gain a comprehensive understanding of their properties. The addition of SF and WGP to PGCM resulted in a 9.9% and 21.6% increase in thermal conductivity, respectively. Furthermore, the addition of SF and WGP facilitated higher CO2 sequestration rates for PGCM (49.76% and 44.05%, respectively), while after carbonation, the strength loss rates were reduced to 16.8% and 13.35%, respectively. Finally, a simple sustainability analysis showed that the utilisation of silica-rich waste in PGCM has environmental sustainability benefits.
•Silica-rich waste was used to enhance the CO2 capture capacity and mechanical properties of PGCM.•The 56-day compressive strength of PGCM with a 9% addition of waste glass powder reached 37.6 MPa.•The incorporation of silica-rich waste into PGCM enhances its thermal conductivity.•The additions of silica fume and waste glass powder facilitated higher CO2 sequestration rates for PGCM (49.76% and 44.05%, respectively).•The utilisation of silica-rich waste in PGCM has environmental sustainability benefits.
The surface roughness and optoelectronic property of SnO2 film are improved by introducing hydroxyl groups on FTO surface, resulting in the champion power conversion efficiency of the corresponding ...perovskite solar cells is improved from 18.28% to 19.51%.
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•The more hydroxyl groups are introduced on the surface of FTO glass.•The interface between FTO glass and SnO2 film is strengthened.•The SnO2 film with low defect density shows high electrical conductivity.•The SnO2 film shows a suitable energy level alignment with perovskite layer.•The champion device exhibits an elevated efficiency of 19.51% and better stability.
Interfacial engineering has been considered as an effective technique to improve the photovoltaic performance of perovskite solar cells (PSCs). Here, the interface between tin oxide (SnO2) film and fluorine-doped tin oxide (FTO) glass is dealt with a piranha solution, resulting in more hydroxyl groups on the surface of FTO glass. SnO2 film is fabricated by spin-coating SnCl2·2H2O precursor. Our results demonstrate that SnO2 film exhibits high electricalconductivity, low electron trap density, and suitable energy level. Furthermore, SnO2 film with low roughness is beneficial to fabricate high-quality perovskite film. Then, the PSCs with the structure of FTO/SnO2/Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3/Spiro-OMeTAD/Au are also fabricated. The highest power conversion efficiency (PCE) of PSCs increases from 18.28% to 19.51%, and the average PCE enhances from 17.82% to 18.89%. The optimized PSC shows the long-term stability and remains 97% of its initial PCE after 4000 h on-shelf lifetime test.
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