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To further promote the industrial application of medium/high entropy intermetallics, a bulk of FeCoNi2Al medium entropy intermetallic ingot with 16 kg as the research object was prepared in this study. Microstructure and mechanical properties of the as-cast alloy were studied and analyzed in detail. Moreover, characteristic structural components were obtained via investment casting route, by which the forming performance of the alloy was evaluated. Results show that the FeCoNi2Al medium entropy intermetallic ingot has good composition uniformity. The as-cast alloy is composed of B2 primary phase with dendritic morphology and interdendritic L12+B2 phase eutectic structure with lamellar morphology. The tensile strength of the as-cast alloy is 1115 MPa at room temperature, and the elongation is 4.6%. At 650 ℃, the tensile strength of the as-cast alloy is 434 MPa, and the elongation can reach 14.6%. Melt fluidity of the FeCoNi2Al medium entropy intermetallic is lower than that of TC4 alloy but better than that of TiAl-4822 alloy. When the thickness of the characteristic structural component is 2 mm, the plate casting is incompletely filled and a mass of shrinkage porosity is formed within the casting. Moreover, the cessation mechanism of flow for the molten alloy is due to the accumulation of solid particles at the tip of flow. Results of this research will lay a certain technical foundation for the casting process optimization and industrial application of medium/high entropy intermetallics.

The objective of this study was to investigate the umami characteristics of soy sauce using electronic tongue evaluation and amino acid composition and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI−TOF MS) analysis. The soy sauce peptides were isolated from soy sauce using XAD−16 macroporous resin combined with ethanol solution. The results showed that the soy sauce peptide fraction eluted by 60% ethanol (SS−60%) exhibited a prominent umami taste, and the umami scores were highly positively correlated with the amino acid nitrogen contents of soy sauces. The umami scores of SS−60% were significantly positively correlated with the contents of free amino acids. Especially, Phe showed the highest positive correlation with the umami scores. In addition, five characteristic ion peaks with m/z at 499, 561, 643, 649, and 855 were identified in the peptide mass fingerprinting. Therefore, this study provides new insights into the umami characteristics for the taste evaluation and reality identification of soy sauce.

The casting simulation software ProCAST was used to achieve the simulation of the filling and solidification process of the high Nb-TiAl alloy impeller investment casting. The influence of the casting and filling process on the filling and solidification characteristics of alloy melt filling, shrinkage cavity and porosity was studied, and the corresponding process was optimized. The casting test and the non-destructive testing analysis of the casting were carried out, and the anatomical analysis of the casting was performed to verify the distribution of the shrinkage cavity and porosity. The mechanical properties of the impeller at room temperature and high temperature were studied using attached test rods. The results show that ProCAST software is more accurate in predicting shrinkage cavity and porosity of the high Nb-TiAl casting, and the process scheme is optimized by simulation and prediction results to avoid the formation of large shrinkage cavity and porosity in casting, only micro shrinkage cavity less than 22 μm is existed in the final casting. All castings are fully filled, with the tensile strength about 580 MPa at room temperature and about 450 MPa at high temperature of 850 ℃.

Abstract Stretchable hydrogels have been used for a number of biomedical applications. This research focused on the study of a highly stretchable and tough hydrogel made of gelatin and polyacrylamide towards transdermal drug delivery applications. Four drug compounds, nicotine, lidocaine hydrochloride, diltiazem hydrochloride and diclofenac sodium, were used for the evaluation. The release rates of these compounds follow an order: lidocaine > diltiazem > nicotine > diclofenac, which showed a strong correlation between the release rate with their solubility in water at pH 5.5. The kinetics study showed a linear and sustainable release of all tested drugs in the first 8 hours. Experiments were conducted in vitro on replicated human skin. Cytotoxicity studies indicate hydrogel is nontoxic to human cells. The highly stretchable and tough characters of the hydrogel the strength of the hydrogel reduce the severity of wear and tear issues over time for transdermal drug release.

Aimed at the great metallographic structure differences between every part of the large-scale thin-wall complex integral precise titanium alloy casting, a non-destructive evaluation method based on metallographic structure statistical analysis is proposed. Under the non-destructive condition, the casting skin structure information is given by means of handheld microscope. The casting skin structure statistic model is established. And the result of integral casting structure is given. Through comparative analysis between non-destructive evaluation (Method A) and metallography detection of the dissect sample (Method B), the results show that the non-destructive evaluation evaluates the metallographic structure effectively. The mean value and half-width of the grain size distribution curves fit the characteristic of Gaussian distribution. And the grain size mean value in both two methods increase linearly along with the casting thickness, and the slope deviation is within the limits of 6%; the half-width relative deviation increases exponentially along with the casting thickness, approached 26%.

To decrease the impact of the regular Ni/Cu/Ni coating on the magnetic performance of sintered NdFeB device, alkaline system of HEDP complexing agent was applied to directly electro-deposit copper layer on NdFeB matrix, then nickel layer was electrodeposited on the copper layer and Cu/Ni coating was finally obtained to replace the regular Ni/Cu/Ni coating. The influence of concentration of HEDP complexing agent on deposition course was tested by electrochemical testing; morphology of copper layer was characterized by SEM, XRD and TEM; the binding force of copper layer and the thermal reduction of magnetic of NdFeB caused by electrodeposited coating were respectively explored through the thermal cycle test and thermal demagnetization test. The results show that the concentration of HEDP has great impact on the deposition overpotential of copper. In the initial electrodepositing stage, copper particles precipitate at the grain boundaries of NdFeB magnets with a preferred (111) orientation. The copper layer is compact and has enough binding force with the NdFeB matrix to meet the requirements in SJ 1282-1977. Furthermore, the thermal demagnetization loss rate of the sintered NdFeB with the protection of Cu/Ni coating is significantly less than that with the protection of Ni/Cu/Ni coating.

A numerical simulation method was used to study the radio frequency plasma spheroidization process of TiAl alloy powder. The effects of velocity field and temperature field on the motion trajectory and mass change of TiAl alloy powder with different particle size were analyzed.The results show that the temperature of powder particles increases rapidly under high temperature plasma, surface evaporation cause the reduction of particle size, and particles with small size tend to evaporate quickly. The motion trajectory of particles with different sizes in the lower end of the cooling tube is different obviously, small particles tend to enter the air outlet,while the larger particles are easy to fall down to the bottom of the cooling tube to be collected. Increasing air flow rate can improve the velocity of air flow in the spheroidizing system, causing larger particles to be taken away by the air, resulting in yield reduction. The simulation results of TiAl alloy powder spheroidization are close to the experimental results refer to parameters such as powder size distribution, average particle size and powder yield, and the model is in good accordance with the actual process of the spheroidization.

The shell mold-HIP forming process of TC4 pre-alloyed powder was investigated. The shrinkage of the molding part was revealed, and the microstructure and tensile property of the alloy as well as the interface between the alloy and mold were analyzed. Results show that the molding part with complete shape and a relative density of 98% is achieved by mold-HIP forming process. During densification, there is a small amount of shrinkage along the length and width of the molding part, while it is much larger along the depth, which reaches 30% in the centre; the process results in fine uniform basketweave microstructure, with a minority of equiaxed α grains surrounding the lamellar; the plasticity of the shell mold-HIP alloy is more than 1.5 times as much the casting alloy; the ultimate tensile strength of the shell mold-HIP alloy is up to and even higher than the level of the forged alloy. There is no obvious interface reaction between the TC4 alloy and shell mold during the HIP process, while a loose layer of about 10μm is formed on the alloy surface of the part.

The application and feature of Ti alloy and TiAl alloy for aviation at home and abroad were briefly introduced. According to the patent application status in Ti alloy field, the development of Ti alloy casting technology was analyzed in the recent thirty years, especially the transformation in aviation. Along with the development of aeronautional manufacturing technology and demand of high performance aircraft, Ti alloy casting is changing towards to be large, integral and complicated, and the evolution of TiAl alloy casting increases the operating temperature of the Ti alloy casting for aviation. Moreover, the Ti alloy forming technology is no longer a single investment casting. Combining with the advantages of casting simulation technology and additive manufacturing technology, it adopts a compound way of development in order to increase its integral casting level and productive efficiency.

We have previously reported that a porous membrane of polyethylene terephthalate (PET) enables significant augmentation of human pluripotent stem cell (hPSC) proliferation and differentiation. The interaction between hPSCs and the PET surface induces β-catenin-mediated wingless/integrated (Wnt) signaling, leading to upregulation of the expression of adhesion molecules in hPSCs. In this study, we sought to unveil mechanisms underlying the role of the PET membrane in hPSC self-renewal and metabolism. We discovered that physicochemical cues of the PET membrane considerably alter hPSC metabolism by increasing the cell yield and suppressing the generation of toxic byproduct, indicating an effective cell self-renewal and a less apoptotic culture environment in the membrane culture system. Furthermore, we discovered that a caspase-8 medicated apoptotic pathway plays a profound role in obstructing hPSCs grown on a traditional tissue culture plate (TCP). Treating hPSCs seeded on a TCP surface with a caspase-8 inhibitor significantly suppressed cellular apoptotic pathway and improved cell proliferation and metabolism. Our experimental results provided valuable insights into signal pathways influencing hPSC self-renewal during routine maintenance and expansion, which would shed light on large-scale preparation of hPSCs for clinical applications.

In this research, Ti-15V-3Cr-3Al-3Sn alloy ingots were prepared using ceramic mold and centrifugal casting. The Ti-15V-3Cr-3Al-3Sn setting casting, for aeronautic engine, with 1.5 mm in thickness was manufactured. The alloy melting process, precision casting process, and problems in casting application were discussed. Effects of Hot Isostatic Pressing and heat treatment on the mechanical properties and microstructure of the Ti-15V-3Cr-3Al-3Sn alloy were studied.

Using TiAl alloy to substitute superalloy is a hot topic in aeroengine industry because of its low density,high elevated temperature strength, and anti-oxidization ability. In this research, Ti-47.5AL-2Cr-2Nb-0.2B alloy was used as the test material. By applying a combination process of ceramic shell mold and core making, vacuum arc melting and centrifugal pouring, and heat isostatic pressing (HIP) and heat treatment (HT) etc., the TiAl vortex agitator casting for aeroengine was successfully made. This paper introduced key techniques in making the TiAl vortex agitator with investment casting process, provided some experimental results including mechanical properties and machinability, and explained some concerns that could affect applications of TiAl castings.

Abstract: A study on the interaction between TiAl alloy and zirconia was carried out in argon atmosphere. The micrographic observations of the cross-section perpendicular to the interface were obtained using a scanning electron microscope with a dedicated energy dispersive spectrometer (SEM/EDS). The results showed that firstly TiAl alloy spreads on the ceramic surface, and then infiltrates into the pores between ceramic particles accompanied by a chemical reaction. The whole ceramic mold is broken into tiny blocks. A multiple fission reaction mechanism was developed to explain the interaction between TiAl alloy and zirconia.

3,4-bis(3-nitrofurazan-4-yl) furoxan (DNTF) is one of the third-generation energetic compounds with excellent comprehensive properties, which can be added to polymer bonded explosive (PBX) to improve energy levels and regulate sensitivity, so the compatibility of DNTF with other components in PBX, especially the binder, is the first question. Herein, two typical hydrocarbon polymers commonly used in PBX, which are hydroxyl-terminated polybutadiene (HTPB) and polyisobutylene (PIB), were selected as the binder, and the compatibility of HTPB and PIB with DNTF was investigated by differential scanning calorimetry (DSC), the vacuum stability test (VST), and in situ infrared spectroscopy (in situ IR). The results of compatibility experiments were verified by using the binding energy and solubility parameter criteria in molecular dynamics (MD). Experimental and MD simulation results showed that DNTF could be compatible with PIB but incompatible with HTPB. The frontier molecular orbital theory in quantum chemistry (QC) was adopted to explore the frontier orbital electron distribution and energy levels of DNTF/HTPB and DNTF/PIB composite systems to better understand the microscopic compatibility mechanism. The compatibility results of the two composite systems were explained from the perspective of electron transfer. All these can deduce that a hydrocarbon polymer binder with a saturated carbon–hydrogen bond at the end of the molecular chain has good compatibility with DNTF, compared with a hydroxyl group, which has bad compatibility with DNTF. [ABSTRACT FROM AUTHOR]