Hot Deformation Behavior and Microstructure Evolution Mechanisms of Ti6Al4V Alloy under Hot Stamping Conditions.

Through the study of the thermal rheological behavior of Ti6Al4V alloy at different temperatures (500 °C, 600 °C, 700 °C, and 800 °C) and different strain rates (0.1 s-1, 0.05 s-1, 0.01 s-1, and 0.005 s-1), a constitutive model was developed for Ti6Al4V alloy across a wide temperature range in the hot stamping process. The model's correlation coefficient reached 0.9847, indicating its high predictive accuracy. Hot processing maps suitable for the hot stamping process of Ti6Al4V alloy were developed, demonstrating the significant impact of the strain rate on the hot formability of Ti6Al4V alloy. At higher strain rates (>0.05 s-1), the hot processing of Ti6Al4V alloy is less prone to instability. Combining hot processing maps with hot stamping experiments, it was found that the forming quality and thickness uniformity of parts improved significantly with the increase in stamping speed. The phase composition and microstructures of the forming parts under different heating temperature conditions have been investigated using SEM, EBSD, XRD, and TEM, and the maximum heating temperature of hot stamping forming was determined to be 875 °C. The recrystallization mechanism in hot stamping of Ti6Al4V alloys was proposed based on EBSD tests on different sections of a hot stamping formed box-shaped component. With increasing deformation, the effect of dynamic recrystallization (DRX) was enhanced. When the thinning rate reached 15%, DRX surpassed dynamic recovery (DRV) as the dominant softening mechanism. DRX grains at different thinning rates were formed through both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX), with CDRX always being the dominant mechanism.

LMD and LC-MS-based chemical constituents and pharmacological effects assessment for two different processing methods of the root of Paeonia lactiflora Pall.

The plant of Paeonia lactiflora Pall. belongs to Ranunculaceae, and its root can be divided into two categories according to different processing methods, which included that one was directly dried without peeling the root of the P. lactiflora (PR), and the other was peeled the root of the P. lactiflora (PPR) after boiled and dried. To evaluate the difference of chemical components, UPLC-ESI-Q-Exactive Focus-MS/MS and UPLC-QQQ-MS were applied. The distribution of chemical components in different tissues was located by laser microdissection (LMD), especially the different ingredients. A total of 86 compounds were identified from PR and PPR. Four kind of tissues were isolated from the fresh root of the P. lactiflora (FPR), and 54 compounds were identified. Especially the content of gallic acid, albiflorin, and paeoniflorin with high biological activities were the highest in the cork, but they were lower in PR than that in PPR, which probably related to the process. To illustrate the difference in pharmacological effects of PR and PPR, the tonifying blood and analgesic effects on mice were investigated, and it was found that the tonifying blood and analgesic effects of PPR was superior to that of PR, even though PR had more constituents. The material basis for tonifying blood and analgesic effect of the root of P. lactiflora is likely to be associated with an increase in constituents such as paeoniflorin and paeoniflorin lactone after boiled and peeled. The study was likely to provide some theoretical support for the standard and clinical application.

Finite Element Simulation and Microstructural Evolution Investigation in Hot Stamping Process of Ti6Al4V Alloy Sheets.

Titanium alloy hot stamping technology has a wide range of application prospects in the field of titanium alloy part processing due to its high production efficiency and low manufacturing cost. However, the challenges of forming titanium alloy parts with large depths and deformations have restricted its development. In this study, the hot stamping process of a Ti6Al4V alloy box-shaped part was investigated using ABAQUS 2020 software. The thermodynamic properties of a Ti6Al4V alloy sheet were explored at different temperatures (400 °C, 500 °C, 600 °C, 700 °C, 800 °C) and different strain rates (0.1 s-1, 0.05 s-1, 0.01 s-1). In addition, the influence law of hot stamping process parameters on the minimum thickness of the formed part was revealed through the analysis of response surface methodology (RSM), ultimately obtaining the optimal combination of process parameters for Ti6Al4V alloy hot stamping. The experimental results of the hot stamping process exhibited a favorable correlation with the simulated outcomes, confirming the accuracy of the numerical simulation. The study on the microstructure evolution of the formed parts showed that grain refinement strengthening occurred in the part with large deformation, and the formed box-shaped parts exhibited a uniform and fine microstructure overall, demonstrating high forming quality. The achievements of the work provide important guidance for the fabrication of titanium alloy parts with large depths and deformations used in heavy industrial production.

Factors Mediating the Link Between Socioeconomic Status and Academic Outcomes of Children With Intellectual Disability.

The study explores the influence of socioeconomic status (SES) on the academic outcomes of children with intellectual disability (ID), and the role of parental participation and parental attitudes toward educational communicators in this process. A total of 305 children with ID from special needs schools and their parents and teachers in China completed the survey. A structural equation model was built to explore the relation between the factors. Results indicated SES not only positively predicts the academic outcomes, but also predicts academic outcomes through the chain mediation of parental participation and parental attitudes towards educational communicators. Findings show the robustness of the Family Investment Model in Chinese contexts. Moreover, the role of parental participation and parental attitudes towards educational communicators cannot be ignored.

Study on the Effect of the Pre-Forming of 22MnB5 Steel in Indirect Hot Stamping.

Based on the indirect hot-stamping test system, the effect of pre-forming on the microstructure evolution (grain size, dislocation density, martensite phase transformation) and mechanical properties of the blank in indirect hot stamping is systematically studied using ultra-high-strength steel 22MnB5. It is found that the average austenite grain size slightly decreases with the increase in pre-forming. After quenching, the martensite also becomes finer and more uniformly distributed. Although the dislocation density after quenching slightly decreases with the increase in pre-forming, the overall mechanical properties of the quenched blank are not greatly affected by pre-forming under the combined effect of the grain size and dislocation density. Then, this paper discusses the effect of the pre-forming volume on part formability in indirect hot stamping by manufacturing a typical beam part. According to the numerical simulations and experimental results, when the pre-forming volume increases from 30% to 90%, the maximum thickness thinning rate of the beam part decreases from 30.1% to 19.1%, and the final beam part has better formability and more uniform thickness distribution results when the pre-forming volume is 90%.

Investigation of the Hot Stamping-in-Die Quenching Composite Forming Process of 5083 Aluminum Alloy Skin.

Aluminum alloy has been used as the skin material for rail vehicles and automobiles to meet the requirements of environmental protection. The hot stamping-in-die quenching composite forming (HFQ) process is a promising technology to compensate for the poor formability of the aluminum alloy sheet at room temperature. In this paper, the high-temperature mechanical properties of 5083 aluminum alloy under various temperature (200 °C, 300 °C, 400 °C, 450 °C) and strain rate conditions (0.01 s-1, 0.10 s-1, 1.00 s-1) were investigated by uniaxial tensile tests. The finite element software of PAM-STAMP was employed to simulate the forming process of high-speed train skin. The effects of forming method and process parameters on the minimum thickness and springback of the skin were analyzed using the Response Surface Methodology (RSM). After parameter optimization, the forming experiment verified the simulation results and the test part met the quality requirements: the thickness above 3.84 mm and the springback within 1.1 mm. Mechanical properties of the sheet before and after HFQ were examined by uniaxial tensile tests at room temperature. It can be inferred from the comparison that the yield strength of the Al5083 sheet increases, but the elongation decreases from the HFQ process.

Isorhynchophylline inhibits inflammatory responses in endothelial cells and macrophages through the NF-κB/NLRP3 signaling pathway.

BACKGROUND: Atherosclerosis is a chronic inflammatory disease of arterial wall, which is closely related to inflammatory reaction. In this study, the anti-inflammatory effect of isorhynchophylline was studied by NF- κB / NLRP3 pathway. METHODS: (1) ApoE-/- mice were fed with high-fat diet to establish atherosclerotic model, while C57 with the same genetic background was fed with common diet as control group. Body weight was recorded and blood lipids were detected. The expression of NLRP3, NF-κB, IL-18 and Caspase-1 in aorta was detected by Western-Blot and PCR, and plaque formation was detected by HE and oil red O staining. (2) Lipopolysaccharide interfered with Human Umbilical Vein Endothelial Cells (HUVECs) and RAW264.7 to form inflammatory model, and was treated with isorhynchophylline. The expression of NLRP3, NF-κB, IL-18 and Caspase-1 in aorta was detected by Western-Blot and PCR, and the ability of cell migration was detected by Transwell and scratch test. RESULTS: (1) the expression of NLRP3, NF- κB, IL-18 and Caspase-1 in aorta of model group was higher than that of control group, and plaque formation was obvious. (2) the expressions of NLRP3, NF- κB, IL-18 and Caspase-1 in HUVECs and RAW264.7 model groups were higher than those in control group, while isorhynchophylline decreased their expression and enhanced cell migration ability. CONCLUSION: Isorhynchophylline can reduce the inflammatory reaction induced by lipopolysaccharide and promote the ability of cell migration.

Theoretical Investigation of Forming Process of Aluminum Alloy Rail Vehicle Side Window.

With the vigorous development of rail transit trains around the world and the emergence of global environmental pollution and energy shortages, the world has an urgent need for manufacturing technology for lightweight aluminum alloy rail transit train components. This paper mainly studied the superplastic forming law of 5083Al for rail transit. Through the high-temperature tensile test and blowing forming experiments, the superplastic properties of 5083Al were determined. Based on this, the die design, finite element simulation, and forming experiment of the rail vehicle side window were carried out. In order to study the superplastic deformation behavior of industrial 5083Al under complex stress conditions, the influence of the depth, area ratio, and friction coefficient of the pre-forming die on the part thickness distribution is simulated. The side window is made of a high-strength 5083Al sheet in the form of bending at both ends to ensure the strength of the connection between the overall side window and the side wall skeleton. The variation law of the side wall forming height of 5083Al box-shaped parts was studied. The efficient manufacture of parts that meet quality standards was made possible by the optimization of the pressure profile. The microstructure changes of the material after superplastic forming were studied by Energy Dispersive Spectrometer (EDS) and Electron Backscattered Diffraction (EBSD).

Deciphering the pharmacological mechanisms of Chaenomeles Fructus against rheumatoid arthritis by integrating network pharmacology and experimental validation.

Chaenomeles Fructus is a plant that can be used for both food and medicine. Modern studies have shown that Chaenomeles Fructus has anti-inflammatory and immunosuppressive effects on arthritis. However, the mechanism of action of Chaenomeles Fructus on rheumatoid arthritis (RA) and its main active ingredients are still unclear. This study was aimed at devising an integrated strategy for investigating the bioactivity constituents and possible pharmacological mechanisms of Chaenomeles Fructus against RA. The components of Chaenomeles Fructus were analyzed using UPLC-Q-Exactive orbitrap MS techniques and applied to screen the active components of Chaenomeles Fructus according to their oral bioavailability and drug-likeness index. Then, we speculated on the potential molecular mechanisms of Chaenomeles Fructus against RA through a network pharmacology analysis. Finally, the potential molecular mechanisms of Chaenomeles Fructus against RA were validated in a complete Freund's adjuvant (CFA)-induced RA rat model. We identified 48 components in Chaenomeles Fructus and screened seven bioactive ingredients. The results of the network pharmacology prediction and the experimental verification results were analyzed by Venn analysis, and the experimental results concluded that Chaenomeles Fructus mainly interferes with the inflammation of RA by inhibiting arachidonic acid metabolism and the MAPK signaling pathway. This study identified the ingredients of Chaenomeles Fructus by UPLC-Q-Exactive orbitrap MS and explained the possible mechanisms of Chaenomeles Fructus against RA by integrating network pharmacology and experimental validation.

Bioactivity-Guided Separation of Anti-Cholinesterase Alkaloids from Uncaria rhynchophlly (Miq.) Miq. Ex Havil Based on HSCCC Coupled with Molecular Docking.

As an important source of cholinesterase inhibitors, alkaloids in natural products have high potential value in terms of exerting pharmacological activities. In this study, a strategy for targeted preparation of cholinesterase inhibitors in Uncaria rhynchophlly (Miq.) Miq. ex Havil (UR) by high-speed counter-current chromatography was provided. In the method, a two-phase polar solvent system composed of ethyl acetate/n-butanol/water (1:4:5, v/v/v) was used, which isolated five alkaloids from the UR extract for the first time. All alkaloids were identified by HR-ESI-MS and NMR as 7-epi-javaniside (1), vincosamide (2), strictosamide (3), cadambine (4), and 3α-dihydrocadambine (5). The poorly resolved compounds 2 and 3 were separated by preparative HPLC (prep-HPLC). Among them, compounds 1, 4, and 5 were firstly obtained from UR. The purity of these plant isolates was 98.8%, 98.7%, 99.2%, 95.7%, and 98.5%, respectively. Compounds 1-5 exhibited an inhibitory effect on acetyl-cholinesterase and butyryl-cholinesterase with an IC50 from 1.47 to 23.24 µg/mL and 1.01 to 18.24 µg/mL. Molecular docking and inhibitory activities indicated that compound 1 showed stronger inhibitory activity on acetyl-cholinesterase and butyryl-cholinesterase.

Experimental Characterization of Viscoelastic Behaviors of Nano-TiO2/CaCO3 Modified Asphalt and Asphalt Mixture.

The purpose of this paper is to promote the application of nano-TiO2/CaCO3 in bituminous materials and present an experimental characterization of viscoelastic behaviors of bitumen and bituminous mixture modified by nano-TiO2/CaCO3. In this work, a series of viscoelastic behavior characterization tests were conducted, including dynamic shear rheometer (DSR) test for bitumen, uniaxial static compression creep test and dynamic modulus test for bituminous mixture. Moreover, various viscoelastic models with clear physical meanings were used to evaluate the influence of nano-TiO2/CaCO3 on the macroscopic performance of bitumen and bituminous mixture. The results show that bitumen and its mixtures are time-temperature dependent. The Christensen-Anderson-Marasteanu (CAM) model of frequency sweep based on DSR test indicated that adding nano-TiO2/CaCO3 can effectively capture the sensitivity of temperature. In addition, the incorporation of nano-TiO2/CaCO3 in bituminous mixture can significantly enhance the high-temperature anti-rutting, and slightly improve the low-temperature anti-cracking as well. At the same time, the modified Burgers model can accurately describe the viscoelastic behavior of bituminous mixtures in the first two creep stages, reflecting the consolidation effect of bituminous mixture. Also, the generalized Sigmoidal model can accurately grasp the characteristics of the relationship between dynamic modulus and reduced frequency and achieve good prediction effects in a wider frequency range.

Characterizing thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite.

The effects of different parameters on oxidation rate are non-linear, interactive and diversified in which the change of adequacy of O2 supply is an important indicator. The influence of microstructure on oxidation rate became stronger worsening the fitting linearity to calculate the activation energy based on present method with the decreased adequacy of O2 supply due to the increase of temperature, the decrease of gas flow rate, etc. Here, we proposed a method to characterize thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite. The proposed method improved the linearity and reduced the standard error of Arrhenius plots of oxidized graphite IG-110 (10 L/min reactant gas) and ET-10 (0.2 L/min reactant gas). The value of activation energy of graphite IG-110 oxidized under ASTM D7542 condition is calculated as 220 kJ/mol by this method echoing the results of previous studies with sufficient O2 supply. For the conditions with less O2 supply at low gas flow rate and/or high temperature, the change of microstructure of oxidized graphite should be obtained as an important factor influencing oxidation rate of graphite.

[Identification of Salvia shandongensis new species based on sequences of the plastid psbA-trnH intergenic region].

To identify Salvia shandongensis and its relatives at molecular level, the psbA-trnH intergenic region of three species including Salvia shandongensis, Salvia miltiorrhiza and S. miltiorrhiza f. alba were amplified and sequenced. Sequences were assembled with CodonCode Aligner. The K2P genetic distances between Salvia shandongensis and its relatives were calculated and UPGMA tree was performed by MEGA5.0. The results indicated that the lengths of psbA-trnH regions of Salvia shandongensis were about 391 bp, while the lengths of psbA-trnH regions of Salvia miltiorrhiza and S. miltiorrhiza f. alba were about 386 bp. The psbA-trnH sequences showed considerable variations between species and thus were revealed as a promising candidate for barcoding of Salvia shandongensis and its relatives. The intra-specific genetic distances of Salvia shandongensis were 0, while the intra-specific genetic distances of Salvia miltiorrhiza and S. miltiorrhiza f. alba were 0.002 and 0.001 respectively. Additionally, the genetic distance of Salvia shandongensis and Salvia miltiorrhiza ranged from 0.034 to 0.04, and the genetic distance of Salvia shandongensis and S. miltiorrhiza f. alba ranged from 0.005 to 0.008, the intra-specific genetic distances of Salvia shandongensis were much smaller than that of Salvia miltiorrhiza and S. miltiorrhiza f. alba; clustering results showed that there were obvious differences between Salvia shandongensis, Salvia miltiorrhiza and S. miltiorrhiza f. alba, which was consistent with morphological characteristics. This study not only firstly provides the scientific basis for establishing the taxonomy position in molecular level and revealing their genetic relationships of S. shandongensis, S. miltiorrhiza and S. miltiorrhiza f. alba; but also provides DNA molecular identification scientific basis for the development of new medicinal plant resources of Salvia shandongensis. Our results suggest that the psbA-trnH intergenic spacer region can be used as a barcoding to identify Salvia shandongensis, Salvia miltiorrhiza and S. miltiorrhiza f. alba.

Protective effects of gallium, germanium, and strontium against ovariectomized osteoporosis in rats.

The effects of trace elements of gallium (Ga), germanium (Ge), and strontium (Sr) on ovariectomized (OVX) osteopenic rats were studied in this paper. The urine calcium content, serum calcium, and phosphorus contents, bone mineral content, mineral dissolution, and mechanical strength of the osteopenic rats were analyzed respectively. After the rats were fed with Ga, Ge, and Sr diet for 8 weeks, respectively, the urine calcium content decreased (P < 0.01). Plasma calcium and phosphate concentrations decreased in the order of OVX group > Ge group > Sr group > Ga group > Sham group. Mineral content increased in the order of OVX group < Ge group < Sr group < Ga group < Sham group. A dramatic decrease in calcium solubility was found both in the gallium and strontium treated animals (P < 0.05). However, the same result did not occur in germanium treated groups. The data provide an important proof of concept that gallium and strontium might be a new potential therapy for the management of postmenopausal osteoporosis in humans.